CT Sizing Calculation of 11kV System-Rev0-Ver3

THIS SUBMISSION IS DECLARED TO BE STRICTLY IN ACCORDANCE WITH THE REQUIREMENTS OF THE CONTRACT

SIGNATURE

QATAR POWER TRANSMISSION SYSTEM EXPANSION PHASE VII (Substations) CONTRACT NO. GTC/123/2006

SIEMENS CONSORTIUM-GTC/123/2006 SIEMENS AG GERMANY

SIEMENS LIMITED INDIA

SUBSTATION NAME / CIRCUIT NAME

Mosemeer, Abu Hamour central, Al Soudan, Ain Khalid South, Al Wadi, MIC-2, MIC-3,QRE,EDS,Khore Community, Al Dhahiya West, Al Jumailyah, Khore Junction, NDQ, Muraikh North, South West Wakrah-1, NBK-2, Abu Thaila Modification, RLF-3, Al Dhahiya, Al Waab Super, MIC Super, Wakrah-2, Lusail Development Super1,Ain Hamad, Ain Khalid south.

PROJECT DRAWING NUMBER

PH7-3B-10-15-C001

SUBCONTRACTOR / SUPPLIER

0 REV

29-11-2007 DATE

DRAWING/DOCUMENT DESCRIPTION

FIRST ISSUE MODIFICATION

R.K. DRAWN SCALE

DESIGN REPORT FOR CURRENT TRANSFORMER (CT) & VOLTAGE

N.A.

TRANSFORMER (VT) SIZING FOR 11kV SYSTEM Document No.:-

TOTAL NO. OF PAGES VER

SIEMENS

V.H CHECK

GTC123-BN00-AQA-10001

91 PAGES 3

V.A. APPRD SIZE A4

SIEMENS

PROJECT:GTC/123/2006

Index

S.No.

DESCRIPTION

PAGE NUMBER

1

PURPOSE

1

2

DESIGN INPUT

1

3

ASSUMPTIONS

1

4

DESIGN CRITERIA

2

5

CALCULATIONS

2

6

RESULT OF STUDY

3

7

ATTACHMENTS

3

ANNEXURE 1

6-80

ANNEXURE 2

81-82

ANNEXURE 3

83

ANNEXURE 4

84-90

ANNEXURE 5

91

PH7-3B-10-15-C001, Rev 0

Page 2 of 91

SIEMENS 1.0


PURPOSE: This document is intended to establish the minimum sizes of -

Current transformer in terms of Knee point voltage & Rated burden

-

Voltage transformer in terms of Rated burden for various feeders of 11KV for the following mentioned substations: Mosemeer Abu Hamour Central Al Soudan Al Wadi Al Jumailyah Khore Junction MIC -2 MIC -3 QRE EDS Khore Community Al Dhahiya West Muraikah North South West Wakrah 1 NDQ NBK -2 RLF-3 MIC Super Al Dhahiya Al Waab Super Lusail Development Super 1 Wakrah 2 Abu Thaila substation modification Ain Hamad Ain Khalid south

2.0

DESIGN INPUT : 1. Project contract document 2. Relay catalogue for relay burden

PH7-3B-10-15-C001, Rev 0

Page 3 of 91

SIEMENS

3.0


ASSUMPTIONS : 1. Power Transformer 32/40MVA, 66/11kV, %age impedance at principal tapping is assumed as 16.33%. 2. Power Transformer 20/25MVA, 66/11kV, %age impedance at principal tapping is assumed as 12.58%.. 3. Power Transformer 7.5/10MVA, 33/11kV, %age impedance at principal tapping is assumed as 12%. 4. Power Transformer 25/30MVA, 33/11kV, %age impedance at principal tapping is assumed as 12.58%. 5. 500kVA, 11/0.415kV Earthing Transformer, %age impedance at principal tapping is assumed as 9.60% 6. 1000kVA, 11/0.415kV Earthing Transformer, %age impedance at principal tapping is assumed as 6.00 % 7. 2000kVA, 11/0.415kV Earthing Transformer, %age impedance at principal tapping is assumed as 12.0%

4.0

DESIGN CRITERIA: KNEE POINT VOLTAGE Apart from rated short time rating of the system, to arrive at minimum knee point voltage, value for steady state through fault current values needs to be determined. Considering the rated capacity of the bus bars of 11kV, the fault level considered is 31.5kA. PARAMETERS FOR CABLE BETWEEN CT & RELAY PANEL Cross section taken is 4 mm2. Calculation for resistance at 75 deg. C: Resistance at 20 deg. C = 4.61 ohms / Km Value of Alpha (Temp. coefficient) at 20 deg. C for copper = 0,00393 / deg. C Resistance at 75 deg. C = 4.61 (1 + 0.00393 (75-20)) = 5.61 ohms / kM Calculation of Loop resistance of the cable between CT & Relay panel: Taking length of cable between CT & Relay panel as 50 meter Loop resistance = 2 x Length of cable (in kM) X resistance at 75 deg. C (in ohms/kM) = (2 x 70 x 5.61) / 1000 = 0.785 ohms Considering 20% safety margin as per contract requirement, (clause 12), = 0.785 * 1.2 = 0.942 ohms All CT sizing calculations, have been done for a cable length of 50mts. This is the maximum length possible.

PH7-3B-10-15-C001, Rev 0

Page 4 of 91

SIEMENS


RATED BURDEN Rated burden selected for a CT/VT shall be more than the sum of relay/metering burden connected across CT/VT.

5.0

CALCULATIONS: Calculations performed for the CT/VT parameters are enclosed in following annexure: Annexure # 1: CT Knee point voltage calculations for the 11kV feeders Annexure # 2: CT burden (in VA) calculations for the 11kV feeders Annexure # 3: VT burden (in VA) calculations for 11kV the feeders

6.0

RESULT OF STUDY: Calculation results show that selected parameters for CT/VT are adequate to meet the minimum requirements.

7.0

ATTACHMENTS: 1. Annexure # 1: CT Knee point voltage calculations for 11kV feeders 2. Annexure # 2: CT burden (in VA) calculations for 11kV feeders 3. Annexure # 3: VT burden (in VA) calculations for 11kV feeders 4. Annexure # 4: Relay back-up sheets 5. Annexure #5: LSOH Power Cable Data Sheet

PH7-3B-10-15-C001, Rev 0

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SIEMENS

ANNEXURE 1

Incomer Feeder (Typical bay no: A18,A28) Type:1 Configuration 40MVA, 66/11kV transformer,Earthing/auxiliary transformer rating of 500kVA Applicable substations:Mosemeer,Abu Hamour central,Al Wadi,MIC-2,MIC-3,QRE,Khore Community,Al Dhahiya West, NBK-2, Al Soudan, Ain Khalid south

66kV side Core-1 50/1 Class-PX Vk≥100 Rct≤1.2 Io<30ma at Vk

66/11KV 32/40MVA ONAN/ONAF

11/0.415KV 500KVA

Cable and trafo differential protection (7SD52)

Core-3 2500/1 Class-PX Vk≥250 Rct≤9 Io<30ma

To partial busbar differential protection (7SJ61)

Core-2 2500/1 Class-5P20/1.0 Rct≤8 10VA

To Directional Overcurrent & earth fault / Metering (6MD6 & 7SJ62)


To Transformer REF (11kV side) & Main differential protection (7SJ61 & 7UT613)

Core-1 750/1 Class-PX Vk≥250 Rct≤6 Io<25ma 15VA

Core-1 750/1 Class-5P20 15VA

To Back-up earth fault (7SJ61)


11kV Bus


Core-2 50/1 Class-PX Vk≥100 Rct≤1.2 Io<30ma

To REF protection for Earthing transformer (7SJ61)

To REF protection for 11kV side (7SJ61)


Feeder =A18, =A28

Note: - 40 MVA LV side Core-4 is not applicable for NDQ, Muraikh North, South West Wakrah-1, NBK-2

CT knee point voltage calculation for 7SJ61 relay for 11kV Incomer Feeders =A18,=A28 (connected across core-1 ) Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

Length of cable between CT and Relay Cable Resistance for 4 mm²at 75°C 20% margin on Cable resistance Loop Resistance ( 2R L )

= = = = =

Loop Burden in VA Current Transformer resistance (R ct) CT Internal Burden in VA

= = =

PH7-3B-10-15-C001, Rev 0

2500 /1 1 amp. 70 meter 5.610 Ohms/Km 5.61x1.2 Ohms/Km 6.732 Ohms/Km 0.942 Ohms (I)² x 0.942 = 9.00 Ohms (I)² x 9 =

(Relay will be mounted in Relay panel)

0.942 9.00

Page 6 of 91


SIEMENS

ANNEXURE 1

Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): = I High set point = The required K'SSC

20

atleast

IN Value 20 will be selected for calculations RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = 2*0.05 RBC = (Loop Burden+ Relay Burden)

= =

b) Knee point voltage : The calculated value of knee point voltage is

=

0.100 VA 1.042 VA

(0.942+0.1)

Ihigh set point x I2N x (Ri+RBC) 1.3 x Ipn

Knee Point voltage required

20% margin on Vk value

=

20 x (9+1.042) x 1 1.3

=

154.49 volts

=

185.39

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition To establish that CT rated knee point volatge is atleast 2 times that voltage developed across the CT in case of through fault condition with one of the CT saturated, the formula used is : (For determining the Voltage developed across CT, a current of 1.5 times of the maximum possible through fault current has been considered) Vk > 2 x 1.5 x I f x (Rct + 2RL ) Where If is magnitude of through fault current Considering infinite source,the maximum through fault current on 40 MVA transformer would be: %age impedance at 40 MVA = 0.1633 Taking a negative tolerance of 15% = 0.1388

Vk

If

=

If

=

40 1.732 x 11 x 0.1388 15.1262 kA 1.5x15126.2x(9+0.942 )x2

>

2500 >

180.46

volts

The minimum CT knee point Voltage shall be selected more than above

PH7-3B-10-15-C001, Rev 0

Page 7 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7UT613 relay for 11kV Incomer Feeders =A18,=A28 (connected across core-1 ) Formula Used a) Transient dimensioning factor (k td): 3 For transformer, k td = b) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC I SCC x ktd = I PN Where: ISSC = symmetrical short-circuit current IPN = CT rated primary current ISN = CT rated secondary current Considering infinite source at 11 kV ,the maximum through fault current on 40 MVA transformer would be: %age impedance at 40 MVA = 0.1633 Taking negative tolerance of 15% = 0.1388 ISSC

=

ISSC

=

40 1.732 x 11 x 0.1388 15.1262 kA

K'SSC

=

15126.2 x 3

K'SSC to be considered for calculations

=

2500 18.15

Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA Relay Burden = 2*0.05 = RBC = (Loop Burden+ Relay Burden) =

0.100 VA 1.042 VA

(0.942+0.1)

c) Knee point voltage : The calculated value of knee point voltage is

=

(RBC+ Ri ) X ISN X K'SSC 1.3


=

(1.042 + 9) x 1 x 18.15 1.3

Knee Point voltage required 20% margin on Vk value

= =

140.20 168.24

volts volts


PH7-3B-10-15-C001, Rev 0

Page 8 of 91


SIEMENS

ANNEXURE 1

Adequacy checking calculations for 7SJ62 and 6MD6 relay for 11kV Incomer Feeders =A18,=A28 (connected across core-2 ) a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC

=

Also K'SSC

=

20 atleast RBN+ Ri x KSSC RBC + Ri

Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA

=

RBN = Nominal Burden of CT in VA

=

10 VA

Relay Burden = 2*0.05 RBC = (Loop Burden+ Relay Burden)

=

0.100 VA 1.042 VA

=

8.0 VA

(0.942+0.1) =

K'SSC

=

(10+8) x20 (1.042+8)

Calculated Value for K' SSC

=

39.81

>

20

Since the selected K' SSC is more than Minimum required K' SSC (20), Hence selected CT is OK

PH7-3B-10-15-C001, Rev 0

Page 9 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7SJ61 type used for Partial Bus bar protection Feeders =A18,=A28 (connected across core-3 ) Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

2500 1 amp.

Length of cable between CT and Relay Cable Resistance for mm²at 75°C 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =

70 5.610 6.732 0.942

Loop Burden in VA Current Transformer resistance (R ct)

=

=

meter Ohms/Km Ohms/Km Ohms

(I)² x 0.942 = 9.00 Ohms

CT Internal Burden in VA = (I)² x 9 Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): = I High set point = 20 The required K'SSC

=


0.942 9.000

atleast

IN RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = 2*0.05 = = RBC = (Loop Burden+ Relay Burden) b) Knee point voltage :

0.100 VA 1.042 VA

(0.942+0.1) Ihigh set point x I2N x (Ri+RBC)

The calculated value of knee point voltage is

=


=


= =

1.3 x Ipn 20 x (1.042+9) x 1 1.3 154.49 185.39

volts volts


PH7-3B-10-15-C001, Rev 0

Page 10 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7SD5 relay for 11kV incoming feeders =A18, =A28(connected across Core-4) Current Transformer Ration (CTR) = 2500 /1 = 1 amp. Relay Normal Current (IN) Length of cable between CT and Relay Cable Resistance for 4 mm²at 75°C 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =


=

CT Internal Burden in VA

=

70 meter 5.610 Ohms/Km 6.732 Ohms/Km 0.942 Ohms =

Formula Used a) Transformer dimensioning factor (k td): For line differential protection ktd

(I)² x 0.942 = 9.00 Ohms (I)² x 9

=

=


0.942 9.000

1.20

b) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC

=

I SCC x ktd I PN

Where: ISSC = symmetrical short-circuit current IPN = CT rated primary current ISN = CT rated secondary current Considering infinite source at 11kV, the maximum through fault current on 40 MVA trafo would be : %age impedance at 40 MVA = 0.1633 Taking negative tolerance of 15% = 0.1388 = 40 ISSC 1.732 x 11 x 0.1388 ISSC

=

K'SSC

15.1262 kA

=

15126.2x1.2 2500


=

Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA Relay Burden = 2*0.05 = = RBC = (Loop Burden+ Relay Burden)

7.26

0.100 VA 1.042 VA

(0.942+0.1)


=



=

(1.042+9) x1x7.26 1.3


= =

56.08 67.30

volts


PH7-3B-10-15-C001, Rev 0

Page 11 of 91


SIEMENS

ANNEXURE 1

CT calculation for 7SJ61 relay for 11kV Incomer Feeders =A18,=A28 (connected across 11kV Neutral side CTs of 500KVA) Current Transformer Ration (CTR) = 2500 /1 = 1 amp. Relay Normal Current (IN) Length of cable between CT and Relay

=

Cable Resistance for 4 mm²at 75°C 20% margin on cable resistance

= = =

Loop Resistance ( 2R L )

=



70 meter 5.610 Ohms/Km 5.61x1.2 6.732 Ohms/Km

(As per contract document)

0.942 Ohms =

(I)² x 0.942 = 9.00 Ohms (I)² x 9 =

= =

0.942 9.00

Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): =

The required K'SSC

I High set point =

20

atleast


= =

b) Knee point voltage : The calculated value of knee point

=


=


= =

0.100 VA 1.042 VA

(0.942+0.1)

Ihigh set point x I2N x (Ri+RBC) 1.3 x Ipn 20 x (9+1.042) x 1 1.3 154.49 185.39

volts


Vk

If

=

If

=

40 1.732 x 11 x 0.1388 15.1262 kA

1.5x15126.2x(9+0.942 )x2

>

2500 >

180.46

volts


PH7-3B-10-15-C001, Rev 0

Page 12 of 91


SIEMENS

ANNEXURE 1

CT calculation for 7SJ61 type used for REF protection of 11kV side of Earthing transformer (Applicable for Phase and Neutral side CTs) Current Transformer Ration (CTR) = 50 /1 = 1 amp. Relay Normal Current (IN) Length of cable between CT and Relay Cable Resistance for 4 mm²at 75°C 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =


=


=


70 meter 5.610 Ohms/Km 6.732 0.942 Ohms =

(I)² x 0.942 = 1.20 Ohms (I)² x 1.2

0.942

=

1.2

Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC

=

I High set point =

20

atleast

IN Value 20 will be selected for calculations Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = 2*0.05 RBC = (Loop Burden+ Relay Burden)

= =


=


=

20% margin on vk value

= =

0.100 VA 1.042 VA

(0.942+0.1) Ihigh set point x I2N x (Ri+RBC) 1.3 x Ipn 1.2 x (1.2+1.042) x 1 1.3 34.49 41.39

volts

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition Vk > 1.5(I f x (Rct + 2RL ) x 2) Where I f is magnitude of through fault current

Considering infinite source,the maximum through fault current on 500 KVA transformer would be: = =

%age impedance at 500 KVA Overall Impedance ( taking 15% negative tolerance) If =

500 1.732 x 11 x 0.0816

If =

321.6172 A

0.0960 0.0816

As the through fault current could be ground fault current which can be max 750A, the stablility is being checked for this max value. Vk

>

1.5 x 750 x (1.2 + 0.942 ) x 2 50

>

96.39

volts


PH7-3B-10-15-C001, Rev 0

Page 13 of 91


SIEMENS

ANNEXURE 1

CT calculation for 7SJ61 type used for REF protection of 11kV side of Earthing transformer (Applicable for 500 KVA HV Neutral side CTs) Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

750 amp. 1 amp.

a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC = Also K'SSC

=

20 atleast

RBN+ Ri x KSSC RBC + Ri

Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA RBN = Nominal Burden of CT in VA Relay Burden = 0.05 RBC = (Loop Burden+ Relay Burden)

= = = =

K'SSC

=

(15+6) x20 6+0.992


=

60.06

6.0 VA 15 VA 0.050 VA 0.992 VA

>

20


PH7-3B-10-15-C001, Rev 0

Page 14 of 91


SIEMENS

ANNEXURE 1

Adequecy check for 7SJ61 type used for O/C protection of 11kV side of Earthing transformer Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

50 amp. 1 amp.


=

20 atleast



= = = =

K'SSC

=

(15+1.2) x20 1.2+0.992


=

147.80

1.2 VA 15 VA 0.050 VA 0.992 VA

>

20


PH7-3B-10-15-C001, Rev 0

Page 15 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7SJ61 type used for REF protection of 433 V side of Earthing transformer (Applicable for Neutral side CTs) Current Transformer Ration (CTR) = 750 /1 = 1 amp. Relay Normal Current (IN) Length of cable between CT and Relay Cable Resistance for 4 mm²at 75°C 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =


=



(I)² x 0.942 = 6.00 Ohms


0.942

=

6.000

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1)


volts

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition To establish that CT rated knee point volatge is atleast 2 times that voltage developed across the CT in case of through fault condition with one of the CT saturated, the formula used is : (For determining the Voltage developed across CT, a current of 1.5 times of the maximum possible through fault current has been considered) Vk > 2 x 1.5 x I f x (Rct + 2RL ) Where If is magnitude of through fault current Considering infinite source, the maximum through fault current on 500 KVA transformer would be: = =


If = Vk

0.0960 0.0816

500 1.732 x 0.415 x 0.0816 8.5248 kA

>

1.5x8524.8x(6+0.942 )x2 750

>

236.72

volts


PH7-3B-10-15-C001, Rev 0

Page 16 of 91


SIEMENS

ANNEXURE 1

Incomer Feeder (Typical bay no: A18,A28) Type:2 Configuration 25MVA, 66/11kV transformer,Earthing/auxiliary transformer rating of 500kVA Applicable substations:Al Jumailyah, Khore Junction

66kV side Core-1 50/1 Class-PX Vk≥100 Rct≤1.2 Io<30ma at Vk


11/0.415KV 500KVA

Cable and trafo differential protection (7SD52)







Core-1 750/1 Class-PX Vk≥250 Rct≤6 Io<25ma 15VA




11kV Bus






Feeder =A18, =A28


= =


= = = = =


= = =

PH7-3B-10-15-C001, Rev 0



0.942 9.00

Page 17 of 91


SIEMENS

ANNEXURE 1


20

atleast


= =


=

0.100 VA 1.042 VA

(0.942+0.1)




=

20 x (9+1.042) x 1 1.3

=

154.49 volts

=

185.39


Vk

If

=

If

=

25 1.732 x 11 x 0.1069 12.2750 kA

>

1.5x12275x(9+0.942 )x2 2500

>

146.45

volts


PH7-3B-10-15-C001, Rev 0

Page 18 of 91


SIEMENS

ANNEXURE 1


=

ISSC

=

25 1.732 x 11 x 0.1069 12.2750 kA

K'SSC

=

12275 x 3


=

2500 14.73


0.100 VA 1.042 VA

(0.942+0.1)


=



=

(1.042 + 9) x 1 x 14.73 1.3


= =

113.78 136.54

volts volts


PH7-3B-10-15-C001, Rev 0

Page 19 of 91


SIEMENS

ANNEXURE 1


=

Also K'SSC

=



=


=

10 VA


=

0.100 VA 1.042 VA

=

8.0 VA

(0.942+0.1) =

K'SSC

=

(10+8) x20 (1.042+8)


=

39.81

>

20


PH7-3B-10-15-C001, Rev 0

Page 20 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7SJ61 type used for Partial Bus bar protection Feeders =A18,=A28 (connected across core-3 ) Current Transformer Ration (CTR) = 2500 Relay Normal Current (IN) = 1 amp. Length of cable between CT and Relay = 70 meter Cable Resistance for mm²at 75°C = 5.610 Ohms/Km 20% margin on cable resistance = 6.732 Ohms/Km = 0.942 Ohms Loop Resistance ( 2R L ) Loop Burden in VA = (I)² x 0.942 = = 9.00 Ohms Current Transformer resistance (R ct) CT Internal Burden in VA = (I)² x 9 = Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): = I High set point = 20 The required K'SSC IN RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = 2*0.05 = = RBC = (Loop Burden+ Relay Burden) b) Knee point voltage : The calculated value of knee point

=


=


= =


0.942 9.000

atleast

0.100 VA 1.042 VA

(0.942+0.1) Ihigh set point x I2N x (Ri+RBC) 1.3 x Ipn 20 x (1.042+9) x 1 1.3 154.49 185.39

volts volts


PH7-3B-10-15-C001, Rev 0

Page 21 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7SD5 relay for 11kV incoming feeders =A18, =A28(connected across Core-4) Current Transformer Ration (CTR) = 2500 /1 = 1 amp. Relay Normal Current (IN) Length of cable between CT and Relay Cable Resistance for 4 mm²at 75°C 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =


=


=


Formula Used a) Transformer dimensioning factor (k td): For line differential protection ktd

(I)² x 0.942 = 9.00 Ohms (I)² x 9

=

=


0.942 9.000

1.20

b) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC

=

I SCC x ktd I PN

Where: ISSC = symmetrical short-circuit current IPN = CT rated primary current ISN = CT rated secondary current Considering infinite source at 11kV, the maximum through fault current on 25 MVA trafo would be : %age impedance at 25 MVA = 0.1258 Taking negative tolerance of 15% = 0.1069 = 25 ISSC 1.732 x 11 x 0.1069 ISSC

=

K'SSC

12.2750 kA

=

12275x1.2 2500


=


5.89

0.100 VA 1.042 VA

(0.942+0.1)


=



=

(1.042+9) x1x5.89 1.3


= =

45.50 54.60

volts


PH7-3B-10-15-C001, Rev 0

Page 22 of 91


SIEMENS

ANNEXURE 1


=


= = =


=


70 meter


5.610 Ohms/Km 5.61x1.2 6.732 Ohms/Km


0.942 Ohms =

(I)² x 0.942 = 9.00 Ohms (I)² x 9 =

= =

0.942 9.00


The required K'SSC

I High set point =

20

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1)


volts


Vk

If

=

If

=

25 1.732 x 11 x 0.1069 12.2750 kA

>

1.5x12275x(9+0.942 )x2 2500

>

146.45

volts


PH7-3B-10-15-C001, Rev 0

Page 23 of 91


SIEMENS

ANNEXURE 1


= = = =


=


=



(I)² x 0.942 = 1.20 Ohms (I)² x 1.2

0.942

=

1.2


=

I High set point =

20

atleast


= =


=


=


= =

0.100 VA 1.042 VA


volts

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition Vk > If x (Rct + 2RL ) x 2 Where I f is magnitude of through fault current

Considering infinite source,the maximum through fault current on 500 KVA transformer would be: %age impedance at 500 KVA Overall Impedance ( taking 15% negative tolerance)

= =

If =

500 1.732 x 11 x 0.0816

If =

321.6172 A

0.0960 0.0816


750 x (1.2 + 0.942 ) x 2

>

50 >

64.26

volts


PH7-3B-10-15-C001, Rev 0

Page 24 of 91


SIEMENS

ANNEXURE 1

Adequecy check for 7SJ61 type used for REF protection of 11kV side of Earthing transformer (Applicable for 500 KVA HV Neutral side CTs) Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

750 amp. 1 amp.


=

20 atleast



= = = =

K'SSC

=

(15+6) x20 6+0.992


=

60.06

6.0 VA 15 VA 0.050 VA 0.992 VA

>

20


PH7-3B-10-15-C001, Rev 0

Page 25 of 91


SIEMENS

ANNEXURE 1


= =

50 amp. 1 amp.


=

20 atleast



= = = =

K'SSC

=

(15+1.2) x20 1.2+0.992


=

147.80

1.2 VA 15 VA 0.050 VA 0.992 VA

>

20


PH7-3B-10-15-C001, Rev 0

Page 26 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7SJ61 type used for REF protection of 433 V side of Earthing transformer (Applicable for Neutral side CTs) Current Transformer Ration (CTR) = 750 /1 Relay Normal Current (IN) = 1 amp. Length of cable between CT and Relay Cable Resistance for 4 mm²at 75°C 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =


=



(I)² x 0.942 = 6.00 Ohms

CT Internal Burden in VA = (I)² x 6 Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC = I High set point = 20

0.942

=

6.000

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1)


volts

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition To establish that CT rated knee point volatge is atleast 2 times that voltage developed across the CT in case of through fault condition with one of the CT saturated, the formula used is : (For determining the Voltage developed across CT, a current of 1.5 times of the maximum possible through fault current has been considered) Vk > 2 x 1.5 x I f x (Rct + 2RL ) Where If is magnitude of through fault current Considering infinite source, the maximum through fault current on 500 KVA transformer would be: %age impedance at 500 KVA Overall Impedance ( taking 15% negative tolerance) If =

If = Vk

= =

0.0960 0.0816

500 1.732 x 0.415 x 0.0816 8.5248 kA

>

1.5x8524.8x(6+0.942 )x2 750

>

236.72

volts


PH7-3B-10-15-C001, Rev 0

Page 27 of 91


SIEMENS

ANNEXURE 1

Incomer Feeder (Typical bay no: A18,A28) Type:3 Configuration 40MVA, 66/11kV transformer,Earthing/auxiliary transformer rating of 1000kVA Applicable substations : NDQ, Murraikh North, South west wakrah,Lusail Development Super 1

66kV side Core-2 100/1 Class-5P20 15VA


Core-3 400/1 Class-PX Vk≥250 Rct≤9 Io<30ma at Vk

Core-1 100/1 Class-PX Vk≥100 Rct≤0.4 Io<30ma at Vk/2

11/0.415KV 1000KVA











11kV Bus




Feeder =A18, =A28


= =


= = = = =


= = =

PH7-3B-10-15-C001, Rev 0



0.942 9.00

Page 28 of 91


SIEMENS

ANNEXURE 1


20

atleast


= =


=

0.100 VA 1.042 VA

(0.942+0.1)




=

20 x (9+1.042) x 1 1.3

=

154.49 volts

=

185.39


Vk

If

=

If

=

40 1.732 x 11 x 0.1388 15.1262 kA 1.5x15126.2x(9+0.942 )x2

>

2500 >

180.46

volts


PH7-3B-10-15-C001, Rev 0

Page 29 of 91


SIEMENS

ANNEXURE 1


=

ISSC

=

40 1.732 x 11 x 0.1388 15.1262 kA

K'SSC

=

15126.2 x 3


=

2500 18.15


0.100 VA 1.042 VA

(0.942+0.1)


=



=

(1.042 + 9) x 1 x 18.15 1.3


= =

140.20 168.24

volts volts


PH7-3B-10-15-C001, Rev 0

Page 30 of 91


SIEMENS

ANNEXURE 1


=

Also K'SSC

=



=


=

10 VA


=

0.100 VA 1.042 VA

=

8.0 VA

(0.942+0.1) =

K'SSC

=

(10+8) x20 (1.042+8)


=

39.81

>

20


PH7-3B-10-15-C001, Rev 0

Page 31 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7SJ61 type used for Partial Bus bar protection Feeders =A18,=A28 (connected across core-3 ) Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

2500 1 amp.

Length of cable between CT and Relay #REF! 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =

70 5.610 6.732 0.942


=

=


(I)² x 0.942 = 9.00 Ohms


=


0.942 9.000

atleast

IN RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = 2*0.05 RBC = (Loop Burden+ Relay Burden)

= =

b) Knee point voltage :

0.100 VA 1.042 VA

(0.942+0.1) Ihigh set point x I2N x (Ri+RBC)

The calculated value of knee point voltage is

=


=


= =

1.3 x Ipn 20 x (1.042+9) x 1 1.3 154.49 185.39

volts volts


PH7-3B-10-15-C001, Rev 0

Page 32 of 91


SIEMENS

ANNEXURE 1


=


= = =


=


=


=




0.942 Ohms =

(I)² x 0.942 = 9.00 Ohms (I)² x 9

0.942

=

9.00


The required K'SSC

I High set point =

20

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1)


volts


Vk

If

=

If

=

40 1.732 x 11 x 0.1388 15.1262 kA

1.5x15126.2x(9+0.942 )x2

>

2500 >

180.46

volts


PH7-3B-10-15-C001, Rev 0

Page 33 of 91


SIEMENS

ANNEXURE 1


= = = =


=


=



(I)² x 0.942 = 0.40 Ohms (I)² x 0.4

0.942

=

0.4


=

I High set point =

20

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1) Ihigh set point x I2N x (Ri+RBC) 1.3 x Ipn 20 x (0.4+1.042) x 1 1.3 22.18 26.62

volts

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition Vk > 1.5(I f x (Rct + 2RL ) x 2) Where I f is magnitude of through fault current

Considering infinite source,the maximum through fault current on 1000 KVA transformer would be: %age impedance at 1000 KVA Overall Impedance ( taking 15% negative tolerance) If =

If =

= =

0.0600 0.0510

1000 1.732 x 11 x 0.051 1029.1751 A


1.5 x 750 x (0.4 + 0.942 ) x 2

>

100 >

30.20

volts


PH7-3B-10-15-C001, Rev 0

Page 34 of 91


SIEMENS

ANNEXURE 1

Adequacy check for 7SJ61 type used for REF protection of 11kV side of Earthing transformer (Applicable for 1000 KVA HV Neutral side CTs) Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

750 amp. 1 amp.


=

20 atleast



= = = =

K'SSC

=

(15+6) x20 6+0.992


=

60.06

6.0 VA 15 VA 0.050 VA 0.992 VA

>

20


PH7-3B-10-15-C001, Rev 0

Page 35 of 91


SIEMENS

ANNEXURE 1


= =

100 amp. 1 amp.


=

20 atleast



= = = =

K'SSC

=

(15+1.2) x20 1.2+0.992


=

147.80

1.2 VA 15 VA 0.050 VA 0.992 VA

>

20


PH7-3B-10-15-C001, Rev 0

Page 36 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7UT613 relay for 11kV Incomer Feeders to 1000 KVA EAT-(connected across core-3 ) Formula Used a) Transient dimensioning factor (k td): = 3 For transformer, k td b) Effective symmetrical short-circuit current factor (K' SSC): I SCC x ktd The required K'SSC = I PN

Where: ISSC = symmetrical short-circuit current IPN = CT rated primary current ISN = CT rated secondary current

Considering infinite source at 11 kV ,the maximum through fault current on 1 MVA transformer would be: %age impedance at 1 MVA = 0.0600 Taking negative tolerance of 15% = 0.0510 ISSC

=

1 1.732 x 11 x 0.051

=

ISSC

=

K'SSC

= K'SSC to be considered for calculations

1.0292 kA 1029.17505444336 x 3 400 7.72

=

7.72

=

(0.942+0.1)

Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA Relay Burden = 2*0.05 RBC = (Loop Burden+ Relay Burden)

=


=



=

(1.042 + 9) x 1 x 7.72 1.3


= =

59.62 71.55

0.100 VA 1.042 VA

volts volts


PH7-3B-10-15-C001, Rev 0

Page 37 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7SJ61 type used for REF protection of 433 V side of Earthing transformer (Applicable for Neutral side CTs) Current Transformer Ration (CTR) = 1500 /1 Relay Normal Current (IN) = 1 amp. Length of cable between CT and Relay Cable Resistance for 4 mm²at 75°C 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =


=



(I)² x 0.942 = 7.50 Ohms

CT Internal Burden in VA = (I)² x 7.5 Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC = I High set point = 20

0.942

=

7.500

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1)

Ihigh set point x I2N x (Ri+RBC) 1.3 x Ipn 20 x (7.5+1.042) x 1 1.3 131.42 157.70

volts

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition To establish that CT rated knee point volatge is atleast 2 times that voltage developed across the CT in case of through fault condition with one of the CT saturated, the formula used is : (For determining the Voltage developed across CT, a current of 1.5 times of the maximum possible through fault current has been considered) Vk > 2 x 1.5 x I f x (Rct + 2RL ) Where If is magnitude of through fault current Considering infinite source, the maximum through fault current on 1000 KVA transformer would be: %age impedance at 1000 KVA Overall Impedance ( taking 15% negative tolerance) If =

If = Vk

= =

0.0600 0.0510

1000 1.732 x 0.415 x 0.051 27.2793 kA 1.5x27279.3x(7.5+0.942 )x2

>

1500 >

PH7-3B-10-15-C001, Rev 0

460.58

volts

Page 38 of 91


SIEMENS

ANNEXURE 1

Incomer Feeder (Typical bay no: A18,A28) Type:4 Configuration 25MVA, 66/11kV transformer,Earthing/auxiliary transformer rating of 1000kVA Applicable substations:Abu Thaila Substation Modification





11/0.415KV 1000KVA











11kV Bus




Feeder =A18, =A28


= =


= = = = =


= = =

PH7-3B-10-15-C001, Rev 0



0.942 9.00

Page 39 of 91


SIEMENS

ANNEXURE 1


20

atleast


= =


=

0.100 VA 1.042 VA

(0.942+0.1)




=

20 x (9+1.042) x 1 1.3

=

154.49 volts

=

185.39


Vk

If

=

If

=

25 1.732 x 11 x 0.1069 12.2750 kA

>

1.5x12275x(9+0.942 )x2 2500

>

146.45

volts


PH7-3B-10-15-C001, Rev 0

Page 40 of 91


SIEMENS

ANNEXURE 1


=

ISSC

=

25 1.732 x 11 x 0.1069 12.2750 kA

K'SSC

=

12275 x 3


=

2500 14.73


0.100 VA 1.042 VA

(0.942+0.1)


=



=

(1.042 + 9) x 1 x 14.73 1.3


= =

113.78 136.54

volts volts


PH7-3B-10-15-C001, Rev 0

Page 41 of 91


SIEMENS

ANNEXURE 1


=

Also K'SSC

=



=


=

10 VA


=

0.100 VA 1.042 VA

=

8.0 VA

(0.942+0.1) =

K'SSC

=

(10+8) x20 (1.042+8)


=

39.81

>

20


PH7-3B-10-15-C001, Rev 0

Page 42 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7SJ61 type used for Partial Bus bar protection Feeders =A18,=A28 (connected across core-3 ) Current Transformer Ration (CTR) = 2500 Relay Normal Current (IN) = 1 amp. Length of cable between CT and Relay = 70 meter #REF! = 5.610 Ohms/Km 20% margin on cable resistance = 6.732 Ohms/Km = 0.942 Ohms Loop Resistance ( 2R L ) Loop Burden in VA = (I)² x 0.942 = = 9.00 Ohms Current Transformer resistance (R ct) CT Internal Burden in VA = (I)² x 9 = Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): = I High set point = 20 The required K'SSC IN RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = 2*0.05 = = RBC = (Loop Burden+ Relay Burden) b) Knee point voltage : The calculated value of knee point

=


=


= =


0.942 9.000

atleast

0.100 VA 1.042 VA


volts volts


PH7-3B-10-15-C001, Rev 0

Page 43 of 91


SIEMENS

ANNEXURE 1


=


= = =


=





0.942 Ohms =

(I)² x 0.942 = 9.00 Ohms (I)² x 9 =

= =

0.942 9.00


The required K'SSC

I High set point =

20

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1)


volts


Vk

If

=

If

=

25 1.732 x 11 x 0.1069 12.2750 kA

>

1.5x12275x(9+0.942 )x2 2500

>

146.45

volts


PH7-3B-10-15-C001, Rev 0

Page 44 of 91


SIEMENS

ANNEXURE 1


= = = =


=


=



(I)² x 0.942 = 0.40 Ohms (I)² x 0.4

0.942

=

0.4


=

I High set point =

20

atleast


= =


=


=


= =

0.100 VA 1.042 VA


volts

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition Vk > If x (Rct + 2RL ) x 2 Where I f is magnitude of through fault current


If =

= =

0.0600 0.0510

1000 1.732 x 11 x 0.051 1029.1751 A


750 x (0.4 + 0.942 ) x 2

>

100 >

20.13

volts


PH7-3B-10-15-C001, Rev 0

Page 45 of 91


SIEMENS

ANNEXURE 1

Adequecy check for 7SJ61 type used for REF protection of 11kV side of Earthing transformer (Applicable for 1000 KVA HV Neutral side CTs) Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

750 amp. 1 amp.


=

20 atleast



= = = =

K'SSC

=

(15+6) x20 6+0.992


=

60.06

6.0 VA 15 VA 0.050 VA 0.992 VA

>

20


PH7-3B-10-15-C001, Rev 0

Page 46 of 91


SIEMENS

ANNEXURE 1


= =

100 amp. 1 amp.


=

20 atleast



= = = =

K'SSC

=

(15+1.2) x20 1.2+0.992


=

147.80

1.2 VA 15 VA 0.050 VA 0.992 VA

>

20


PH7-3B-10-15-C001, Rev 0

Page 47 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7UT613 relay for 11kV Incomer Feeders to 1000 KVA EAT-(connected across core-3 ) Formula Used a) Transient dimensioning factor (k td): = 3 For transformer, k td b) Effective symmetrical short-circuit current factor (K' SSC): I SCC x ktd The required K'SSC = I PN

Where: ISSC = symmetrical short-circuit current IPN = CT rated primary current ISN = CT rated secondary current

Considering infinite source at 11 kV ,the maximum through fault current on 1 MVA transformer would be: %age impedance at 1 MVA = 0.0600 Taking negative tolerance of 15% = 0.0510 ISSC

=

ISSC

=

K'SSC

=


=


1 1.732 x 11 x 0.051 1.0292 kA 1029.17505444336 x 3 400 7.72

0.100 VA 1.042 VA

(0.942+0.1)

c) Knee point voltage : The calculated value of knee point

=

(RBC+ Ri ) X ISN X K'SSC


=

(1.042 + 9) x 1 x 7.72 1.3


= =

59.62 71.55

volts volts


PH7-3B-10-15-C001, Rev 0

Page 48 of 91


SIEMENS

ANNEXURE 1


= = = =


=



(I)² x 0.942 = 7.50 Ohms

CT Internal Burden in VA = (I)² x 7.5 Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): = I High set point = 20 The required K'SSC

0.942

=

7.500

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1)

Ihigh set point x I2N x (Ri+RBC) 1.3 x Ipn 20 x (7.5+1.042) x 1 1.3 131.42 157.70

volts



If = Vk

0.0600 0.0510

1000 1.732 x 0.415 x 0.051 27.2793 kA

>

1.5x27279.3x(7.5+0.942 )x2 1500

>

460.58

volts


PH7-3B-10-15-C001, Rev 0

Page 49 of 91


SIEMENS

ANNEXURE 1

Incomer Feeder (Typical bay no: A18,A28) Type:5 Configuration 40MVA, 66/11kV transformer,Earthing/auxiliary transformer rating of 2000kVA Applicable substations:MIC Super , Al Dhahiya,Al Waab Super, Wakrah 2, EDS




Core-3 400/1 Class-PX Vk≥100 Rct≤9 Io<30ma at Vk/2

11/0.415KV 2000KVA











11kV Bus




Feeder =A18, =A28


= =


= = = = =


= = =

PH7-3B-10-15-C001, Rev 0



0.942 9.00

Page 50 of 91


SIEMENS

ANNEXURE 1


20

atleast


= =


=

0.100 VA 1.042 VA

(0.942+0.1)




=

20 x (9+1.042) x 1 1.3

=

154.49 volts

=

185.39


Vk

If

=

If

=

40 1.732 x 11 x 0.1388 15.1262 kA

>

1.5x15126.2x(9+0.942 )x2 2500

>

180.46

volts


PH7-3B-10-15-C001, Rev 0

Page 51 of 91


SIEMENS

ANNEXURE 1


=

ISSC

=

40 1.732 x 11 x 0.1388 15.1262 kA

K'SSC

=

15126.2 x 3


=

2500 18.15


0.100 VA 1.042 VA

(0.942+0.1)


=



=

(1.042 + 9) x 1 x 18.15 1.3


= =

140.20 168.24

volts volts


PH7-3B-10-15-C001, Rev 0

Page 52 of 91


SIEMENS

ANNEXURE 1


=

Also K'SSC

=



=


=

10 VA


=

0.100 VA 1.042 VA

=

8.0 VA

(0.942+0.1) =

K'SSC

=

(10+8) x20 (1.042+8)


=

39.81

>

20


PH7-3B-10-15-C001, Rev 0

Page 53 of 91


SIEMENS

ANNEXURE 1


=


=


= =


0.942 9.000

atleast

0.100 VA 1.042 VA


volts volts


PH7-3B-10-15-C001, Rev 0

Page 54 of 91


SIEMENS

ANNEXURE 1


=


= = =


=


70 meter


5.610 Ohms/Km 5.61x1.2 6.732 Ohms/Km


0.942 Ohms =

(I)² x 0.942 = 9.00 Ohms (I)² x 9 =

= =

0.942 9.00


The required K'SSC

I High set point =

20

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1)


volts


Vk

If

=

If

=

40 1.732 x 11 x 0.1388 15.1262 kA

>

1.5x15126.2x(9+0.942 )x2 2500

>

180.46

volts


PH7-3B-10-15-C001, Rev 0

Page 55 of 91


SIEMENS

ANNEXURE 1


= = = =


=


=



(I)² x 0.942 = 0.60 Ohms (I)² x 0.6

0.942

=

0.6


=

I High set point =

20

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1) Ihigh set point x I2N x (Ri+RBC) 1.3 x Ipn 20 x (0.6+1.042) x 1 1.3 25.26 30.31

volts

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition Vk >1.5( I f x (Rct + 2RL ) x 2) Where I f is magnitude of through fault current


If =

= =

0.1200 0.1020

2000 1.732 x 11 x 0.102 1029.1751 A


750 x (0.6 +, 0.942 ) x 2x1.5

>

200 >

17.34

volts


PH7-3B-10-15-C001, Rev 0

Page 56 of 91


SIEMENS

ANNEXURE 1

Adequacy check for 7SJ61 type used for REF protection of 11kV side of Earthing transformer (Applicable for 2000 KVA HV Neutral side CTs) Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

750 amp. 1 amp.

a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC = =

Also K'SSC

20 atleast

RBN+ Ri x KSSC


=


=

15 VA

Relay Burden = 0.05 RBC = (Loop Burden+ Relay Burden)

= =

0.050 VA 0.992 VA

K'SSC

=

6.0 VA

(15+6) x20 6+0.992


=

60.06

>

20


PH7-3B-10-15-C001, Rev 0

Page 57 of 91


SIEMENS

ANNEXURE 1


= =

200 amp. 1 amp.

a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC = =

Also K'SSC

20 atleast

RBN+ Ri x KSSC


=


=

15 VA

Relay Burden = 0.05 RBC = (Loop Burden+ Relay Burden)

= =

0.050 VA 0.992 VA

K'SSC

=

1.2 VA

(15+1.2) x20 1.2+0.992


=

147.80

>

20


PH7-3B-10-15-C001, Rev 0

Page 58 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7UT613 relay for 11kV Incomer Feeders to 2000 KVA EAT-(connected across core-3 ) Formula Used a) Transient dimensioning factor (k td): 3 For transformer, k td = b) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC

=

I SCC x ktd I PN

Where: ISSC = symmetrical short-circuit current IPN = CT rated primary current ISN = CT rated secondary current Considering infinite source at 11 kV ,the maximum through fault 40 current on 2 MVA transformer would be: %age impedance at 2 MVA = 0.1200 Taking negative tolerance of 15% = 0.1020 ISSC

2

=

1.732 x 11 x 0.102 ISSC

=

K'SSC

=


=


1.0292 kA 1029.17505444336 x 3 400 7.72

0.100 VA 1.042 VA

(0.942+0.1)


=



=

(1.042 + 9) x 1 x 7.72 1.3


= =

59.62 71.55

volts volts


PH7-3B-10-15-C001, Rev 0

Page 59 of 91


SIEMENS

ANNEXURE 1


= = = =


=



(I)² x 0.942 = 15.00 Ohms

CT Internal Burden in VA = (I)² x 15 Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC = I High set point = 20

0.942

=

15.000

atleast


= =


=


=


= =

0.100 VA 1.042 VA

(0.942+0.1)


volts



If = Vk

0.1200 0.1020

2000 1.732 x 0.415 x 0.102 27.2793 kA 1.5x27279.3x(15+0.942 )x2

>

3000 >

434.89

volts


PH7-3B-10-15-C001, Rev 0

Page 60 of 91


SIEMENS

ANNEXURE 1

Incomer Feeder (Typical bay no: A18,A28) Type:6 Configuration: 10MVA, 33/11kV transformer Applicable substations:Ain Hamad 33 KV SIDE

Core-2 750/1 Class - 5P20 15 VA

8.47ohm 750A, 30s NER

33/11 KV 7.5/10MVA ONAN/ONAF

Backup earth fault (7SJ61)

Core-3 800/1 Class - PX Vk≥250 Rct≤9 Io=30mA at Vk/2 Core-2 600-300/1 Class - 5P20/1.0 20 - 10 VA

Core-1 600-300/1 Class - PX Vk≥600 - 300 Rct≤9 - 4.5

Core-1 600-300/1 Class - PX Vk≥ Rct≤9 - 4.5 Io=30mA at Vk/2

11kV side REF Protection (7SJ61)

Partial Bus Bar protection (7SJ61)



Io=30mA at Vk/2

11kV Bus

Feeder =A18, =A28


= =

600 /1 1 amp.

Length of cable between CT and Relay #REF! 20% margin on Cable resistance Loop Resistance ( 2R L )

= = = = =

70 meter 5.610 Ohms/Km 5.61x1.2 Ohms/Km 6.730 Ohms/Km 0.942 Ohms


= = =

PH7-3B-10-15-C001, Rev 0

(I)² x 0.942 = 9.00 Ohms (I)² x 9 =


0.942 9.00

Page 61 of 91


SIEMENS

ANNEXURE 1


20

atleast

IN Value 20 will be selected for calculations RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = 2*0.05 = RBC = (Loop Burden+ Relay Burden)

=


=

0.1 VA 1.042 VA

(0.942 + 0.1)




=

Ratio 600/1 20 x (9 + 1.042) x 1 1.3

Ratio 300/1 20 x (4.5 + 1.042) x 1 1.3

=

154.49 volts

85.26 volts

=

185.39

102.31

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition To establish that CT rated knee point volatge is atleast 2 times that voltage developed across the CT in case of through fault condition with one of the CT saturated, the formula used is : (For determining the Voltage developed across CT, a current of 1.5 times of the maximum possible through fault current has been considered) Vk > 2 x 1.5 x I f x (Rct + 2RL ) Where If is magnitude of through fault current Considering infinite source,the maximum through fault current on 10 MVA transformer would be: %age impedance at 10 MVA = 0.1200 Taking a negative tolerance of 15% = 0.102 If

=

If

=

10 1.732 x 11 x 0.102 5.146 kA Ratio 600/1

Vk

>

Ratio 300/1

1.5 x 5146 x (9 + 0.942 ) x 2

1.5 x 5146 x (4.5 + 0.942 ) x 2

600 >

255.81

300 volts

280.05

volts


PH7-3B-10-15-C001, Rev 0

Page 62 of 91


SIEMENS

ANNEXURE 1

CT knee point voltage calculation for 7UT613 relay for 11kV Incomer Feeders =A18,=A28 (connected across core-1 ) Formula Used a) Transient dimensioning factor (k td): 3.00 For transformer, k td = b) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC I SCC x ktd = I PN Where: ISSC = symmetrical short-circuit current IPN = CT rated primary current ISN = CT rated secondary current Considering infinite source at 11 kV ,the maximum through fault current on 10 MVA transformer would be: %age impedance at 10 MVA = 0.1200 Taking negative tolerance of 15% = 0.1020 ISSC

=

ISSC

=

10.00 1.732 x 11 x 0.102 5.146 kA Ratio 600/1

K'SSC K'SSC to be considered for calculations

=

5146 x 3

5146 x 3

=

600 25.73

300 51.46



=

Ratio 300/1

(0.942 + 0.1)

0.1 VA 1.042 VA

(RBC+ Ri ) X ISN X K'SSC 1.3 Ratio 600/1


=

(1.042 + 9) x 1 x 25.73 1.3


= =

198.75 volts 238.51 volts

Ratio 300/1 (1.042 + 4.5) x 1 x 51.46 1.3 219.38 volts 263.25 volts


PH7-3B-10-15-C001, Rev 0

Page 63 of 91


SIEMENS

ANNEXURE 1


=

Also K'SSC

=


=

(0.942 + 0.1)

20 atleast

Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA RBN = Nominal Burden of CT in VA Relay Burden = 2*0.05 = RBC = (Loop Burden+ Relay Burden)

K'SSC

=

Ratio 600/1 (20 + 8) x 20 (1.042 + 8)


=

61.93

0.1 VA 1.042 VA Ratio 300/1 (10 + 4) x 20 (1.042 + 4) 55.53

> 20 20 Since the selected K' SSC is more than Minimum required K' SSC (20), Hence selected CT is OK

PH7-3B-10-15-C001, Rev 0

Page 64 of 91


SIEMENS

ANNEXURE 1


=


=


= =


0.942 9.000

atleast

0.100 VA 1.042 VA


volts volts


PH7-3B-10-15-C001, Rev 0

Page 65 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for REF protection with 7SJ61 relay (connected across LV neutral core-1) Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC = I High set point = IN

20 atleast

RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden =0.05VA RBC = (Loop Burden+ Relay Burden)

0.05 VA =

(0.942 + 0.05) Ratio 600/1


=

Knee Point voltage required 20% margin on Vk value (As per contract document)

(0.992 + 9) x 1 x 20

= =

0.992 VA Ratio 300/1 (0.992 + 4.5) x 1 x 20

1.3

1.3

153.72 184.47

84.49 101.39

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition To establish that CT rated knee point volatge is atleast 2 times that voltage developed across the CT in case of through fault condition with one of the CT saturated, the formula used is : (For determining the Voltage developed across CT, a current of 1.5 times of the maximum possible through fault current has been considered) Vk > 2 x 1.5 x I f x (Rct + 2RL ) Where If is magnitude of through fault current Considering infinite source,the maximum through fault current on 10 MVA transformer would be: %age impedance at 10 MVA = 0.1200 Taking a negative tolerance of 15% = 0.1020 If

=

If

=

10 1.732 x 11 x 0.102 5.146 kA

Ratio 600/1 Vk

>

>

1.5 x 5146 x (9 + 0.942 ) x 2

Ratio 300/1 1.5 x 5146 x (4.5 + 0.942 ) x 2

600

300

255.81

280.05


PH7-3B-10-15-C001, Rev 0

Page 66 of 91


SIEMENS

ANNEXURE 1

Adequecy check for 7SJ61 type used for O/C protection of 11kV side of Earthing transformer -Core-2 Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

750 amp. 1 amp.


=


Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA RBN = Nominal Burden of CT in VA Relay Burden = 0.05 RBC = (Loop Burden+ Relay Burden) K'SSC

20 atleast

= = = = =

2.2 VA 15 VA 0.050 VA 0.992 VA

(15+2.2) x20 2.2+0.992


=

107.76

>

20


PH7-3B-10-15-C001, Rev 0

Page 67 of 91


SIEMENS

ANNEXURE 1

Incomer Feeder (Typical bay no: A18,A28) Type:7 Configuration 30MVA, 33/11kV transformer,Earthing/auxiliary transformer rating of 1000kVA Applicable substations:RLF-3

33kV side 33/11KV 25/30MVA ONAN/ONAF

NER

Core-1 75/1 Class-PX Vk≥250 Rct≤0.4 Io<30ma at Vk





Core-1 2500/1 Class-PX Vk≥ 250 Rct≤9 Io<30ma

To Transformer Main differential protection ( 7UT613)

11kV Bus

Feeder =A18, =A28


= =

Length of cable between CT and Relay Cable Resistance for 4 mm²at 75°C 20% margin on Cable resistance Loop Resistance ( 2RL )

= = = = =

Loop Burden in VA Current Transformer resistance (Rct) CT Internal Burden in VA

= = =

PH7-3B-10-15-C001, Rev 0



0.942 9.00

Page 68 of 91


SIEMENS

ANNEXURE 1

Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC = I High set point =

20

atleast


= =


=

0.100 VA 1.042 VA

(0.942+0.1)



=


20 x (9+1.042) x 1 1.3

=

154.49 volts

=

185.39

The minimum CT knee point Voltage shall be selected more than above Stability check for REF protection for through fault condition To establish that CT rated knee point volatge is atleast 2 times that voltage developed across the CT in case of through fault condition with one of the CT saturated, the formula used is : (For determining the Voltage developed across CT, a current of 1.5 times of the maximum possible through fault current has been considered) Vk > 2 x 1.5 x If x (Rct + 2RL ) Where If is magnitude of through fault current Considering infinite source,the maximum through fault current on 30 MVA transformer would be: %age impedance at 30 MVA = 0.1258 Taking a negative tolerance of 15% = 0.1069 If

=

If

=

Vk

30 1.732 x 11 x 0.1069 14.7300 kA 1.5x14730x(9+0.942 )x2

>

2500 >

175.73

volts


PH7-3B-10-15-C001, Rev 0

Page 69 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7UT613 relay for 11kV Incomer Feeders =A18,=A28 (connected across core-1 ) Formula Used a) Transient dimensioning factor (ktd): For transformer, ktd 3 = b) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC I SCC x ktd = I PN Where: ISSC = symmetrical short-circuit current IPN = CT rated primary current ISN = CT rated secondary current Considering infinite source at 11 kV ,the maximum through fault current on 30 MVA transformer would be: %age impedance at 30 MVA = 0.1258 Taking negative tolerance of 15% = 0.1069 ISSC

=

ISSC

=

30 1.732 x 11 x 0.1069 14.7300 kA

K'SSC

=

14730 x 3


=

2500 17.68


0.100 VA 1.042 VA

(0.942+0.1)


=



=

(1.042 + 9) x 1 x 17.68 1.3


= =

136.57 163.89

volts volts


PH7-3B-10-15-C001, Rev 0

Page 70 of 91


SIEMENS

ANNEXURE 1


=

Also K'SSC

=



=


=

10 VA

= (0.942+0.1) =

0.100 VA 1.042 VA


=

K'SSC

=

(10+8) x20 (1.042+8)

Calculated Value for K'SSC

=

39.81

8.0 VA

>

20


PH7-3B-10-15-C001, Rev 0

Page 71 of 91


SIEMENS

ANNEXURE 1

CT Knee point voltage calculation for 7SJ61 type used for Partial Bus bar protection Feeders =A18,=A28 (connected across core-3 ) Current Transformer Ration (CTR) Relay Normal Current (IN) Length of cable between CT and Relay Cable Resistance for mm²at 75°C 20% margin on cable resistance Loop Resistance ( 2RL ) Loop Burden in VA Current Transformer resistance (Rct) CT Internal Burden in VA Formula Used a) Effective symmetrical short-circuit The required K'SSC

RBC = Connected Burden across CT in Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = 2*0.05 RBC = (Loop Burden+ Relay Burden)

= = = = = = = = =

=

2500 1 amp. 70 meter 5.610 Ohms/Km 6.732 Ohms/Km 0.942 Ohms (I)² x 0.942 = 9.00 Ohms (I)² x 9 =

I High set point = IN

20

= =


=


=


= =

(Relay will be

0.942 9.000

atleast

0.100 VA 1.042 VA

(0.942+0.1) Ihigh set point x I2N x 1.3 x Ipn 20 x (1.042+9) x 1 1.3 154.49 185.39

volts volts

The minimum CT knee point Voltage

PH7-3B-10-15-C001, Rev 0

Page 72 of 91


SIEMENS

ANNEXURE 1

Outgoing Feeder (Typical bay no: A10,A20) Type:1 Applicable substations:All substations with 11kV switchgear except Ain Hamad

11kV Bus

Core-1 400-300/1 Class-PX Vk≥250-300

To Pilot wire differential, Cable overload protection (SOLKOR)

Rct≤1.75-1.25 Io<30ma Core-2 400-300/1 Class-5P20/1.0 Rct≤3-2 VA Burden -10 VA

To Feeder Overcurrent & earth fault protection / metering (7SJ61 + 6MD6)

CT Knee point voltage calculation for SOLKOR type relay used for Pilot wire protection Applicable for 11kV Outgoing Feeders Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

Length of cable between CT and Relay Cable Resistance for 4 mm²at 75°C 20% margin on cable resistance

= = = = =

Loop Resistance (2RL ) Loop burden in VA; (I) 2 x 2RL Current Transformer resistance (R ct)

=

Short time rating of 11kV system (I sc)

=

Formula Used Knee point voltage requirement V k

>

300 /1 1 amp. 70 5.610 5.61 x 1.2 6.732 0.942

meter Ohms/Km


Ohms/Km Ohms

0.942 VA

=

1.25 Ohms 31.50 kA

50 / In + If / In * (Rct + 2Rl)

Where: In = Rated current, amps. = 1A If = Primary current under maximum steady state through fault cnditions. N = CT ratio = 400-300/1A RL = Lead resistance of single lead from relay to current transformer Rct = Secondary resistance Lead resistance of single lead from relay to current transformer If = Maximum through fault current = 50 x In 50 0.05 ohm Guard relay burden per element (R G) = Knee point voltage requirement V k

>

Ratio 300/1

Required parameters for CTs


50 / In + If / In * (Rct + 2R L + 2RG) Ratio 400/1

>

50/1+50/1 x (1.25+0.942+2x0.05)

50/1+50/1 x (1.75+0.942+2x0.05)

>

164.60

189.60

>

197.52

227.52


PH7-3B-10-15-C001, Rev 0

Page 73 of 91


SIEMENS

ANNEXURE 1

Adequacy checking calculation for 7SJ61 & 6MD6 relay for 11kV Cable feeders (connected across core-2) a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC

=

Also K'SSC

=


=

(0.942+0.1)

20 atleast

Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA RBN = Nominal Burden of CT in VA Ri = Internal CT burden in VA Relay Burden = 2*0.05 RBC = (Loop Burden+ Relay Burden)

=

0.100 VA 1.042 VA

Ratio 300/1

Required parameters for CTs K'SSC

=

(10+2) x20 (1.042+2)


=

78.90

>

20

Ratio 400/1 (+3) x20 (1.042+3) 14.84 20

Since the calculated K' SSC is more than Minimum required K' SSC (20), Hence selected CT is OK

PH7-3B-10-15-C001, Rev 0

Page 74 of 91


SIEMENS

ANNEXURE 1

Outgoing Feeder (A30,A40) Type:2 Applicable substations:Ain Hamad

11kV Bus

Core-1 100/1 Class - 5P10 10VA

To Over current / Earth fault (7SJ61)

Core-2 100/1 Class - 1.0 10VA

Metering

Core-1 750/1 Class - PX Vk≥ Rct≤6 Io<25mA

11/0.415 kV 500 KVA ONAN/ONAF

415V side REF Protection (7SJ61)

Core-1 750/1 Class - PX Vk≥ Rct≤6 Io<25mA

415V side REF Protection (7SJ61)

Adequacy checking calculations for 7SJ61 relay for 11kV Incomer Feeders (connected across core-1) Current Transformer Ration (CTR) Relay Normal Current (IN)

= =

100 /1 1 amp.

Length of cable between CT and Relay

=

70 meter

Cable Resistance for 4.0mm 2 at 750C 20% margin on cable resistance Loop Resistance ( 2R L )

= = =

5.610 Ohms/Km 6.732 Ohms/Km 0.942 Ohms


= = =

(I)² x 0.942 = 1.500 Ohms (I)² x 1.5 =

a) Effective symmetrical short-circuit current factor (K' SSC): = The required K'SSC =


Ri = Internal CT burden in VA RBN = Nominal Burden of CT in VA Relay Burden = 2*0.05 = RBC = (Loop Burden+ Relay Burden)

=

(0.942+0.1)

K'SSC

=

(10 + 1.5) x 20

Also K'SSC

0.942 1.50

20 atleast

Where RBC = Connected Burden across CT in VA

0.1 VA 1.042 VA

(1.042 + 1.5) Calculated Value for K' SSC

=

90.48

>

20.00


PH7-3B-10-15-C001, Rev 0

Page 75 of 91


SIEMENS

ANNEXURE 1

CT knee point voltage calculations for 7SJ61 type used for REF protection of 415 V side of 315kVA transformer (Applicable for Phase and Neutral side CTs) Current Transformer Ration (CTR) = 750 /1 = 1 amp. Relay Normal Current (IN) Length of cable between CT and Relay Cable Resistance for 4.0mm 2 at 750C 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =


= =

70 meter 5.610 Ohms/Km 6.732 Ohms/Km 0.942 Ohms (I)² x 0.942 = 6.000 Ohms

CT Internal Burden in VA = Formula Used a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC

=

(I)² x 6

IHigh set point =

0.942

=

6.000

20

atleast

IN Value 20 will be selected for calculations Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = .1 VA RBC = (Loop Burden+ Relay Burden)

=


=


=


= =

0.1 VA 1.042 VA

(0.942+0.1)

Ihigh set point x I2N x (Ri+RBC) 1.3 x Ipn 20 x (6 + 1.042) x 1 1.3 108.34 130.01

volts



If = Vk

0.0960 0.082

500 (1.732 x415 x 0.0816) 8.525 kA

>

1.5 x 8525 x (6 +0.942) x 2 750

>

236.72

volts


PH7-3B-10-15-C001, Rev 0

Page 76 of 91


SIEMENS

ANNEXURE 1

Bus Coupler (Typical bay no.A12) Type:1

Applicable substations: All substations with 11kV switchgear except Ain Hamad

11kV Bus-2

11kV Bus-1 Core-1 2500/1 Class-PX Vk≥250 Rct≤9 Io<30ma

Core-2 2500/1


Class-PX


Vk≥250 Rct≤9 Io<30ma Core-1 2500/1 Class-5P20/1.0 Rct≤8.5 10 VA

To Overcurrent/Earth fault and Metering (6MD6 + 7SJ61)

CT Knee point voltage calculation for 7SJ61 type used for Partial Bus bar differential protection Applicable for I/C and B/C Current Transformer Ration (CTR) = 2500 /1 = 1 amp. Relay Normal Current (IN) Length of cable between CT and Relay Cable Resistance for 4 mm²at 75°C 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =


=

70 5.610 6.732 0.942 =

(I)² x 0.942 = 9.00 Ohms


=


(I)² x 9

I High set point =

=

20


0.942 9.000

atleast

IN RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = 2*0.05

=

RBC = (Loop Burden+ Relay Burden)

0.100 VA =

(0.942+0.1)

1.042 VA



=


=

20 x (9+1.042) x 1 1.3


= =

154.49 185.39

volts volts


PH7-3B-10-15-C001, Rev 0

Page 77 of 91


SIEMENS

ANNEXURE 1

Adequacy checking calculation for 7SJ61 & 6MD6 relay (connected across core-2 ) a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC

=

Also K'SSC

=


=

(0.942+0.1)

20 atleast

Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA RBN = Nominal Burden of CT in VA Relay Burden = 2*0.05 RBC = (Loop Burden+ Relay Burden)

=

K'SSC

=

(10+8.5) x20 (1.042+8.5)


=

38.78

0.100 VA 1.042 VA

>

20.00


PH7-3B-10-15-C001, Rev 0

Page 78 of 91


SIEMENS

ANNEXURE 1

Bus Coupler (A12) Type:2 Applicable substations:Ain Hamad

11kV Bus-2

11kV Bus-1

Core-2 800/1

Core-1 800/1 Class-PX Vk≥250 Rct≤9 Io<30mA at Vk/2


Class-PX


Vk≥250 Rct≤9 Io<30mA at Vk/2 Core-1 800/1 Class-5P20/1.0 Rct≤8.5 15 VA

To Overcurrent/Earth fault and Metering (6MD6 + 7SJ61)

CT knee point voltage calculations for 7SJ61 type used for Partial Bus bar differential protection Applicable for I/C and B/C Current Transformer Ration (CTR) = 800 /1 = 1 amp. Relay Normal Current (IN) Length of cable between CT and Relay Cable Resistance for 4.0mm 2 at 750C 20% margin on cable resistance Loop Resistance ( 2R L )

= = = =


= =

70 meter 5.610 Ohms/Km 6.730 Ohms/Km 0.942 Ohms (I)² x 0.942 = 9.00 Ohms


=

(I)² x 9

I High set point =

=

20

0.942 9.000

atleast

IN RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA I2N = Relay Normal Current Relay Burden = 0.1 VA

0.1 VA

RBC = (Loop Burden+ Relay Burden)

=

(0.942+0.1)

1.042 VA



=


=

20 x (9+1.042) x 1 1.3


= =

154.49 185.39

volts volts


PH7-3B-10-15-C001, Rev 0

Page 79 of 91


SIEMENS

ANNEXURE 1

Adequacy checking calculation for 7SJ61 & 6MD6 relay (connected across core-1 ) a) Effective symmetrical short-circuit current factor (K' SSC): The required K'SSC

=

Also K'SSC

=


=

(0.942+0.1)

20 atleast

Where RBC = Connected Burden across CT in VA Ri = Internal CT burden in VA RBN = Nominal Burden of CT in VA Relay Burden = 2*0.05 = 0.10VA RBC = (Loop Burden+ Relay Burden)

K'SSC

=

(15+8.5) x20 (1.042+8.5)


=

49.26

0.1 VA 1.042 VA

>

20.00


PH7-3B-10-15-C001, Rev 0

Page 80 of 91


SIEMENS Sr. No.

1

2

Feeder Description

4

6

CT Ratio used

CT Knee Point CT Resistance Voltage (V) (ohms)

Relays connected

Relay Burden (in VA)

VA burden due to Secondary leads

Total VA burden

Remarks

Applicable substations

Rated Burden selected= 10 VA

Al Jumailyah, Khore Junction,Mosemeer,Abu Hamour central,Al Wadi,MIC-2,MIC-3,QRE,Khore Community,Al Dhahiya West, NBK-2, Al Soudan, Ain Khalid south,Abu Thaila Substation Modification,NDQ, Murraikh North, South west wakrah,Lusail Development Super 1,MIC Super , Al Dhahiya,Al Waab Super, Wakrah 2, EDS,RLF-3

Bay =A18,=A28 (Incomer feeder) Core-1, Cl. PX

2500/1

Core-2, 5P20/1.0

2500/1

250

9

7SJ61

7UT613

0.050

0.050

0.942

1.042

6MD6

7SJ62

0.050

0.050

0.942

1.292

Ammeter

0.250

Core-3, Cl. PX

2500/1

250

9

7SJ61

0.050

0.942

0.992

Core-4, Cl. PX

2500/1

250

9

7SD52

0.050

0.942

0.992

50/1 50/1 2500/1 50/1 750/1 750/1

100

1.20

250 100

9.0 1.20

250

6

7SJ61 7SJ61 7SJ61 7SJ61 7SJ61 7SJ61

0.050 0.050 0.050 0.050 0.050 0.050

0.942 0.942 0.942 0.942 0.942 0.942

0.992 0.992 0.992 0.992 0.992 0.992

Mosemeer,Abu Hamour central,Al Wadi,MIC-2,MIC3,QRE,Khore Community,Al Dhahiya West, NBK-2, Al Soudan, Ain Khalid south,Al Jumailyah, Khore Junction

Earthing transformer (500KVA) Core-1, Cl. PX Core-2, 5P20/1.0 Trafo Neutral, Cl. PX (11kV side) Trafo Neutral, Cl. PX (11kV side) Trafo Neutral, 5P20/1.0 (11kV side) Trafo Neutral, Cl. PX (415 V side)

3

ANNEXURE 2



Earthing transformer (1000KVA) Core-1, Cl. PX Core-2, 5P20/1.0 Trafo Neutral, Cl. PX (11kV side) Trafo Neutral, Cl. PX (11kV side) Trafo Neutral, 5P20/1.0 (11kV side) Trafo Neutral, Cl. PX (415 V side)

100/1 100/1 2500/1 100/1 750/1 1500/1

Earthing transformer (2000KVA) Core-1, Cl. PX Core-2, 5P20/1.0 Core-3, Cl. PX Trafo Neutral, Cl. PX (11kV side) Trafo Neutral, Cl. PX (11kV side) Trafo Neutral, 5P20/1.0 (11kV side) Trafo Neutral, Cl. PX (415 V side)

200/1 200/1 400/1 2500/1 200/1 750/1 3000/1

Bay =A12 (Bus sectionalizer) T1, Core-1, 5P20/1.0

100

0.40

250 100

9.0 0.40

500

7.50

100

0.60

100 250 100

9.00 9.0 0.40

450

15.00

2500/1

7SJ61 7SJ61 7SJ61 7SJ61 7SJ61 7SJ61

0.050 0.050 0.050 0.050 0.050 0.050

0.942 0.942 0.942 0.942 0.942 0.942

0.992 0.992 0.992 0.992 0.992 0.992

7SJ61 7SJ61 7UT613 7SJ61 7SJ61 7SJ61 7SJ61

0.050 0.050 0.050 0.050 0.050 0.050 0.050

0.942 0.942 0.942 0.942 0.942 0.942 0.942

0.992 0.992 0.992 0.992 0.992 0.992 0.992

0.942

1.292

7SJ61

6MD6 Ammeter

0.050

0.050


NDQ, Murraikh North, South west wakrah,Lusail Development Super 1,Abu Thaila Substation Modification.



MIC Super , Al Dhahiya,Al Waab Super, Wakrah 2, EDS



Common for all substations with 11kV switchgear except Ain Hamad

0.250

T1, Core-2, Cl. PX

2500/1

9

7SJ61

0.050

0.942

0.992

T2, Core-1, Cl. PX

2500/1

9

7SJ61

0.050

0.942

0.992

PH7-3B-10-15-C001, Rev 0

Mosemeer,Abu Hamour central,Al Wadi,MIC-2,MIC3,QRE,Khore Community,Al Dhahiya West, NBK-2, Al Soudan, Ain Khalid south,Al Jumailyah, Khore Junction

Page 81 of 91


SIEMENS Sr. No.

7

8

Feeder Description

CT Ratio used

Outgoing Feeders =Typ. A10,A20 T1, Core-1, Cl. PX T2, Core-1, 5P20/1.0

400-300/1 400-300/1

Bay =A18,=A28 (Incomer feeder) Core-1, Cl. PX Core-2, 5P20/1.0

600-300/1 600-300/1 800/1

Core-3, Cl. PX 9

ANNEXURE 2

Bay =A18 & =A28 (LV neutral) Core-1, Cl. PX Core-2, 5P20

CT Knee Point CT Resistance Voltage (V) (ohms)

100/1 100/1 750/1

11 Bay =A12,=A22 (Bus sectionalizer) T1, Core-1, CL5P20/1.0 T1, Core-2, Cl. PX T2, Core-1, Cl. PX

800/1 800/1 800/1

VA burden due to Secondary leads

Total VA burden

0.050

0.942 0.942

0.050 0.050


Applicable substations

4.442 1.292


Common for all substations with 11kV switchgear except Ain Hamad

0.942 0.942

1.042 1.292


0.942

0.992

SOLKOR 7SJ61

600-300

9-4.5

250

9

7SJ61 6MD6 Ammeter 7SJ61

9-4.5

7SJ61

0.050

0.942

0.992

7SJ61

0.050

0.942

0.992

6.00

7SJ61

0.050

0.942

0.992

250 250

8.5 9 9

7SJ61 7SJ61 7SJ61

0.942 0.942 0.942

1.092 0.992 0.992

300-250

1.25-1.75

SOLKOR 7SJ61

0.942 0.942

4.442 1.292

6MD6 Ammeter 7UT613 7SJ62

6MD6

3.500 0.050 0.250

Remarks

1.75-1.25

600-300/1 750/1

10 Bay =A30 & =A40 (315kVA transformer feeders) Core-1, 5P10/1.0 Core-2, Cl. 1.0 Cl. PX (415V side)

Relays connected

0.050 0.050 0.250 0.050

0.050 0.050 0.050

0.050

Ain Hamad

Ain Hamad Rated Burden selected= 15 VA

Rated Burden selected= 10 VA Rated Burden selected= 10 VA

Ain Hamad


Ain Hamad

12 Outgoing Feeders =A90, =A70, =A50, =A10,= A20, =A60, =A80, =A100, T1, Core-1, Cl. PX T2, Core-2, 5P20/1.0

400-300/1 400-300/1

PH7-3B-10-15-C001, Rev 0

6MD6 Ammeter

3.500 0.050 0.250

0.050


Ain Hamad

Page 82 of 91


SIEMENS Sr. Feeder Description No. 1 Bay =A14 -T15 Winding-1, 1.0/3P

ANNEXURE 3

VT Ratio used

Relays connected

Total VA Remarks burden

11/ √3 : 0.11/√3

6MD6 Voltmeter

0.050 1.400

1.450


11/ √3 : 0.11/√3

6MD6 Voltmeter

0.050 1.400

1.450


2

Bay =A24 -T16 Winding-1, 1.0/3P

3

Bay =A18, =A28 (Incomer feeder) Winding-1, 1.0/3P

11/ √3 : 0.11/√3

6MD6 Voltmeter AVR

4

Outgoing Feeders (Typ.) =A10,A20 Winding-1, 1.0/3P

11/ √3 : 0.11/√3

6MD6 Voltmeter

PH7-3B-10-15-C001, Rev 0


7SJ62

.

0.050 1.400 1.000

0.050

2.500


0.050 1.400

0.050

1.500


Page 83 of 91

A 2 Overview

CT dimensioning formulae

CT design according to BS 3938/IEC 60044-1 (2000)

K'ssc = Kssc · Rct + Rb (effective) Rct + R' b with K'ssc

W Ktd ·

The design values according to IEC 60044 can be approximately transfered into the BS standard definition by following formula:

I SCC max (required) I pn

The effective symmetrical short-circuit current factor K'ssc can be calculated as shown in the table above.

VK

=

(Rb

+ Rct ) •I sn •K ssc

2

13 .

Example: IEC 600/1, 5P10, 15 VA, Rct = 4 . 60044:

The rated transient dimensioning factor Ktd depends on the type of relay and the primary DC time constant. For relays with a required saturation free time from w 0.4 cycle, the primary (DC) time constant TP has only little influence.

IEC PX or BS: VK =

(15 + 4) •1 •10 V = 146 V 1.3

Rct = 4 .

For CT design according to ANSI/IEEE C 57.13 please refer to page 2/56

Table 2/1 CT requirements

Relay type

Transient dimensioning factor Ktd

Overcurrent-time protection 7SJ511, 512, 531 7SJ45, 46, 60 7SJ61, 62, 63, 64

–

Line differential protection (pilot wire) 7SD600

–

K'ssc =

K'ssc =

Transformer 1.2 1.6

Busbar / Line 1.2 1.6

Gen. / Motor 1.2 1.6

Transformer / Generator differential protection 7UT612 7UT613, 633, 635 7UM62

Transformer 4 3 4

Busbar / Line 4 3 –

Gen. / Motor 5 5 5

Distance protection 7SA522, 7SA6, 7SD5xx*) *) with distance function

I High set point I pn

at least: 20

Line differential protection (without distance function) 7SD52x, 53x, 610 (50 Hz) 7SD52x, 53x, 610 (60 Hz)

Busbar protection 7SS5, 7SS600

Min. required sym. shortcircuit current factor K’ssc

Min. required kneepoint voltage VK VK =

I High set point 13 . •I pn

at least:

I scc max (ext. fault) I pn

VK =

· (Rct + R'b) · Isn

20 · (Rct + R'b) · Isn 13 .

I scc max (ext. fault) · (Rct + R'b) · Isn 13 . •I pn

and:

and:

3 ( K' ssc •I pn )end1 4 = = 4 ( K' ssc •I pn )end2 3

3 (VK •I pn / I sn )end1 4 = = 4 (VK •I pn / I sn )end2 3

K'ssc = I Ktd · scc max (ext. fault) I pn

VK =

and (only for 7SS):

Ktd ·

I scc max (ext. fault) · (Rct + R'b) · Isn 13 . •I pn

and (only for 7SS): 100 · (Rct + R'b) · Isn (measuring range) 13 .

K'ssc = 100 (measuring range) VK =

for stabilizing factors k = 0.5 0.5 primary DC time constant TP [ms] = 30 Ktd (a) 1 Ktd (b) 4

PH7-3B-10-15-C001, Rev 0 Siemens SIP · 2006

K'ssc =

= 50

= 100 = 200 Ktd (a) ·

2 5

4 5

4 5

I scc max (close -in fault) I pn

and:

and: Ktd (b) ·

VK = Ktd (a) ·

I scc max (zone 1- end fault) I pn

Ktd (b) ·

I scc max (close -in fault) · (Rct + R'b) · Isn 13 . •I pn I scc max (zone 1-end fault) · (Rct + R'b) · Isn 13 . •I pn

Page 84 of 91 2/53

A 2 Overview

Protection Coordination

Relay burden

Example 2: Stability-verification of the numerical busbar protection relay 7SS52

The CT burdens of the numerical relays of Siemens are below 0.1 VA and can therefore be neglected for a practical estimation. Exceptions are the busbar protection 7SS60 and the pilot-wire relays 7SD600.

2

Intermediate CTs are normally no longer necessary as the ratio adaptation for busbar and transformer protection is numerically performed in the relay. Analog static relays in general have burdens below about 1 VA. Mechanical relays, however, have a much higher burden, up to the order of 10 VA. This has to be considered when older relays are connected to the same CT circuit. Fig. 2/93

I SCC.max. I pn

In any case, the relevant relay manuals should always be consulted for the actual burden values. =

30 ,000 A = 50 600 A

Burden of the connection leads

According to table 2/1 on page 2/53 Ktd = ½) K'ssc Rb

1 •50 = 25 2 15 VA = = 15 . 1 A2

The resistance of the current loop from the CT to the relay has to be considered:

=

Rrelay

= 0.1 .

Rlead

=

R'b

= Rl + Rrelay = 0.3 . + 0.1 . = 0.4 .

K'ssc

=

=

l

= single conductor length from the CT to the relay in m.

Specific resistance:

2 •0.0175 •50 = 0.3 . 6 4 . + 15. Rct + Rb •K ssc = 4 . + 0.4. Rct + R' b

2 •. •l A

Rlead

. • mm 2 (copper wires) at 20 °C m

.

= 0.0175

A

= conductor cross-section in mm2

•10 = 43.2

Result: The effective K'ssc is 43.2, the required K'ssc is 25. Therefore the stability criterion is fulfilled.

CT design according to ANSI/IEEE C 57.13 Class C of this standard defines the CT by ist secondary terminal voltage at 20 times rated current, for which the ratio error shall not exceed 10 %. Standard classes are C100, C200, C400 and C800 for 5 A rated secondary current. This terminal voltage can be approximately calculated from the IEC data as follows: ANSI CT definition Vs.t.max

= 20 •5 A •Rb •

with Rb

=

Pb I sn

Vs.t.max

=

2

K ssc 20

and I Nsn = 5 A , we get

Pb •K ssc 5A

Example: IEC 600/5, 5P20, 25 VA 60044: ANSI C57.13:

2/56 PH7-3B-10-15-C001, Rev 0

Vs.t.max =

(25 VA •20) = 100 V, acc. to class C100 5A

PageSiemens 85 of 91 SIP · 2006

A 4 Technical Data

4.1

General Device Data

4.1.1

Analog Inputs

Current Inputs Nominal Frequency

fNom

50 Hz or 60 Hz

Nominal Current

INom

1 A or 5 A

Ground Current, Sensitive

INs

= linear range 1.6 A 1)

Burden per Phase and Ground Path - at INom = 1 A - at INom = 5 A - for sensitive ground fault detection at 1 A

(adjustable)

Approx. 0.05 VA Approx. 0.3 VA Approx. 0.05 VA

Current overload capability - Thermal (rms)

100· INom for 1 s 30· INom for 10 s 4· INom continuous 250· INom (half-cycle)

- Dynamic (peak value)

Current overload capability for high-sensitivity input INs 1) - Thermal (rms)

300 A for 1 s 100 A for 10 s 15 A continuous 750 A (half-cycle)

- Dynamic (peak value) 1)

4.1.2

only in models with input for sensitive ground fault detection (see ordering data in Appendix A.1)

Auxiliary Voltage

DC Voltage Voltage supply using integrated converter Rated auxiliary DC VAux

24/48 VDC

60/110/125 VDC

Permissible Voltage Ranges

19 to 58 VDC

48 to 150 VDC

Rated auxiliary DC VAux

110/125/220/250 VDC

Permissible Voltage Ranges

88 to 300 VDC

Permissible AC ripple voltage, Peak to Peak, IEC 60 255-11

15 % of the auxiliary voltage

Power Input

Quiescent

Approx. 3 W

Energized

Approx. 7 W

Bridging Time for Failure/Short Circuit, IEC 60255–11 (in not energized operation)

268

PH7-3B-10-15-C001, Rev 0

= 50 ms at V = 110 VDC = 20 ms at V = 24 VDC

7SJ61 Manual Page 86 of 91 C53000-G1140-C118-7

A 4.1 General

4.1

General

4.1.1

Analog Inputs

Nominal frequency

fN

50 Hz or 60 Hz (adjustable)

IN

1 A or 5 A

Current Inputs Nominal current Power Consumption per Phase and Earth Path - at IN = 1 A

Approx. 0.05 VA

- at IN = 5 A

Approx. 0.3 VA

- for sensitive earth fault detection at 1A

Approx. 0.05 VA

Current Overload Capability per Current Input - thermal (rms)

100 · IN for 1 s 30 · IN for 10 s 4 · IN continuous

- dynamic (pulse current)

250 · IN (half-cycle)

Current Overload Capability for Sensitive Earth Current Input - thermal (rms)

300 A for 1 s 100 A for 10 s 15 A continuous

- dynamic (pulse current)

750 A (half-cycle)

Requirements for current transformers 1st Condition: For a maximum fault current the current transformers must not be saturated under steady-stateconditions n' = 30 2nd Condition: The operational accuracy limit factor n' must be at least 30 or a non- or saturated period of t'AL of at least 1/4 AC cycle after fault inception t'AL = 1/4cycle must be ensured 3 rd Condition: Maximum ratio between primary currents of current transformers at the ends of the protected object

Voltage inputs Nominal voltage UN

80 V to 125 V (adjustable)

Measuring range

0 V to 218.5 V (rms)

Power consumption

At 100 V

= 0.1 VA

Voltage overload capability per phase - thermal (rms)

7SD5 Manual PH7-3B-10-15-C001, C53000-G1176-C169-1

230 V continuous

Rev 0

Page 87 of 91

519

A 4

Page 10 of 10 PH7-3B-10-15-C001, Rev 0

Page 88 of 91

A

PH7-3B-10-15-C001, Rev 0

Page 89 of 91

AVR TECHNICAL DATA SHEET

PH7-3B-10-15-C001, Rev 0

A

Page 90 of 91

A

Sr

LV CABLES

UNIT

1 LV POWER CABLES 1.1 Manufacturer 1.2 Cable type 1.3 Standards 1.4 Rated Voltage V 1.5 Test Voltage (1 min) VAC/min 1.6 Conductor 1) Cross sectional area (Nominal) mm² 2) Material Copper 3) Design (Stranded, sectoral ect) 4) Overall diameter (Approx) mm 5) No. of cores 1.7 Insulation 1.8 Fillers Material - Polypropylene 1.9 Armour bedding Type Nominal Thickness mm 1.10 Armour Type of wire Number of wires No. Diameter of wires - Nominal mm * Wire size higher than specified in BS 6724 1.11 Outer covering Material Nominal Thickness mm Min. thickness mm 1.12 Completed cable Overall diameter - Approx mm Weight per meter - Approx kg Maximum drum length m 1.13 Cable drums Overall diameter - Approx m Width - Approx m Weight loaded - Approx kg 1.14 Continuous current carrying capacity based on the conditions Laid in the ground (Touching each other) a) One circuit A b) Two circuits A c) Three circuits A Drawn in to ducts a) One circuit A b) Two circuits A c) Three circuits A In air One circuit at 50 °C A 1.15 Max conductor temp °C 1.16 Conductor short circuit current carrying capacity for 1 sec. Cable loded as above prior to kA short ckt & final conductor temp of °C 1.17 Min radius of bend around which cable can be laid a) Laid direct m b) In ducts m c) In air m 1.18 Ducts Nominal internal diameter of pipes or mm ducts through which cable can be pulled 1.19 Maximum dc resistance per km of cable at 20 °C of conductor ohm/Km 1.20 Maximum ac resistance of conductor per km of cable at max. ohm/Km conductor temp - 90 °C 1.21 insulation resistance per km of cable per core Mohm 1.22 Manufacturer quality assurance according to ISO 9000, 9001, 9003 & 9004 1.23 Type test certificate to be issued by independent laboratory

REQUIRED 4CX4

4CX6

4CX10

4CX120

4CX150

1CX240

1CX120

1CX95

2CX10

2CX6

2CX16

2CX25

DATA OFFERED 2CX35 3CX4

3CX6

Polypropylene fillers - Wherever necessary

3CX10

3CX16

3CX35

5CX10

5CX6

10 6 16 25 35 4 6 10 16 35 10 6 Copper Copper Copper Copper Copper Copper Copper Copper Copper Copper Copper Copper anded/Circuanded/Circuanded/Circutranded/Sectranded/Secanded/Circ t uanded/Circuanded/Circuanded/Circutranded/Sectanded/Circuanded/Circular 4.02 3.12 4.8 N.A. N.A. 2.52 3.12 4.02 4.8 N.A. 4.02 3.12 2 2 2 2 2 3 3 3 3 3 5 5 XLPE XLPE XLPE XLPE XLPE XLPE XLPE XLPE XLPE XLPE XLPE XLPE

1.4 0.92

27 1.25*

0.8

18.7 750 1000

1.5 1.00

30 1.25

0.8

1200 1040 1110

21.1 960 1000

1.5 1.00

102 82.62 71.40

1200 1040 1345

21.3 1195 1000

1.6 1.08

107 85.60 74.90

131 106.11 91.70

1400 1040 2030

26.1 1850 1000

152 121.60 106.40

187 151.47 130.90

1600 1070 3150

32.0 2860 1000

LSOH Type LTS-1 LSOH Type LTS-1 1.7 1.9 1.16 1.32

Galvanized Steel Wire Armour 35 37 36 1.25 1.25 1.6

163 90

17.16 250

293 90

258 206.40 180.60

312 252.72 218.40

1800 1130 3710

47.1 6900 500

2.3 1.64

44 2.5

1.4

100

8 x OD 8 x OD 8 x OD

21.45 250

335 90

291 232.80 203.70

349 282.69 244.30

2000 1135 4395

51.4 8190 500

2.4 1.72

48 2.5

1.4

100


34.32 250

510 90

421 336.80 294.70

480 388.80 336.00

1600 1070 3030

32.8 2740 1000

1.8 1.24

44 1.6

1

100


17.16 250

328 90

315 252.00 220.50

332 268.92 232.40

1800 1130 1720

32.8 1460 1000

1.6 1.08

AWA 31 1.6*

1

100


13.59 250

282 90

281 224.80 196.70

292 236.52 204.40

1200 1040 1360

22.3 1210 1000

1.6 1.08

28 1.6*

0.8

100


0.57 250

43 90

46 36.80 32.20

56 45.36 39.20

1000 700 560

14.7 460 1000

1.4 0.92

23 1.25*

0.8

100


1.43 250

74 90

77 61.60 53.90

94 76.14 65.80

1200 740 845

18 715 1000

1.5 1.00

29 1.25*

0.8

100


0.86 250

55 90

58 46.40 40.60

70 56.70 49.00

1000 700 650

15.9 550 1000

1.4 0.92

25 1.25*

0.8

100


2.29 250

98 90

99 79.20 69.30

121 98.01 84.70

1200 1040 1055

20.4 905 1000

1.5 1.00

33 1.25

0.8

100


3.58 250

128 90

127 101.60 88.90

157 127.17 109.90

1200 1040 1135

20.4 985 1000

1.6 1.08

32 1.25

0.8

100


5.01 250

158 90

153 122.40 107.10

188 152.28 131.60

1200 1040 1545

23.3 1395 1000

0.57 250

37 90

39 31.20 27.30

47 38.07 32.90

1000 710 615

15.3 515 1000

LSOH Type LTS1 LSOH Type LTS 1 1.7 1.4 1.16 0.92

100


0.86 250

46 90

48 38.40 33.60

59 47.79 41.30

1000 710 725

16.6 625 1000

1.4 0.92

Galvanised Steel Wire 30 22 24 1.6 1.25* 1.25*

1

100


100


1.43 250

64 90

65 52.00 45.50

79 63.99 55.30

1200 740 970

19.5 840 1000

1.5 1.00

32 1.25

0.8

100


2.29 250

83 90

83 66.40 58.10

102 82.62 71.40

1200 1040 1175

21.6 1025 1000

1.6 1.08

36 1.25

0.8

100


5.01 250

134 90

128 102.40 89.60

157 127.17 109.90

1400 1040 2010

25.7 1830 1000

1.8 1.24

34 1.6

1

100


1.43 250

64 90

65 52.00 45.50

79 63.99 55.30

1200 1040 1280

22.9 1130 1000

1.6 1.08

39 1.25

0.8

100


0.86 250

46 90

48 38.40 33.60

59 47.79 41.30

1200 1040 1010

20 860 1000

1.5 1.00

33 1.25

0.8

4 Copper Standed/Circular 2.52 2 XLPE

OCI Cu/XLP/SWA/LSOH BS 6724 600/1000 3500 (5 min)

2CX4

TECHNICAL PARTICULARS - LSOH POWER CABLES

OFFERED 4CX25 4CX50

DATA 4CX16

Polypropylene fillers - Wherever necessary

16.4 600 1000 1200 740 880

79 63.99 55.30

83 66.40 58.10

109 90

7.15 250

100


3.08

2.33

1.83

1.47

1.15

0.927

0.727

0.494

0.387

0.197

0.153

0.16

0.124

0.0968

0.0754

0.197

0.153

0.247

0.193

5.88

4.61

2.33

1.83

3.93

3.08

1.47

1.15

0.927

0.727

0.668

0.524

5.88

4.61

3.93

3.08

2.33

1.83

1.47

1.15

0.668

0.524

2.33

1.83

3.93

3.08

0.8

1000 710 690

59 47.79 41.30

65 52.00 45.50

83 90

3.58 250

100


Polymeric LSOH 0.8

47 38.07 32.90

48 38.40 33.60

64 90

2.29 250

100


Polymeric LSOH 1 1

39 31.20 27.30

46 90

1.43 250

100


0.8

37 90

0.86 250

100


3.93

44 1.6

0.57 250

100


0.8

4 6 10 16 25 50 120 150 240 120 95 Copper Copper Copper Copper Copper Copper Copper Copper Copper Copper Copper Standed/Circular anded/Circuanded/Circutranded/Sectranded/Sectranded/Sectranded/Sectranded/Sectanded/Circuanded/Circuanded/Circu 2.52 3.12 4.02 N.A. N.A. N.A. N.A. N.A. 18.4 13 11.4 4 4 4 4 4 4 4 4 1 1 1 XLPE XLPE XLPE XLPE XLPE XLPE XLPE XLPE XLPE XLPE XLPE

OMAN CABLES Cu/XLP/SWA/LSOH Cu/XLP/SWA/LSOH BS 6724 600/1000 4000/min 600/1000 4000

Cu Stranded

XLPE

LSOH

90

100


4.61

COMPLY

Will be calculated form the insulation resistance constant at 90 °C I.e. 3.67 megaohm.km COMPLY

5.88

Will be calculated form the insulation resistance constant at 90 °C I.e. 3.67 megaohm.km COMPLY COMPLY

Page 91 of 91

PH7-3B-10-15-C001, Rev 0

CT Sizing Calculation of 11kV System-Rev0-Ver3

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