Generator Relay Settings

TITLE :

DOCUMENT NO. PE-DG-233-510-E017 REV NO. : 0 DATE : 14/05/2007 SHEET : 1 OF 21

RELAY SETTING CALCULATIONS FOR GENERATOR RELAY PANELS

JPL, OP JINDAL SUPER TPP (4 X 250 MW) GENERATOR PARAMETERS RATED OUTPUT RATED VOLTAGE RATED CURRENT RATED FREQUENCY RATED POWER FACTOR DIRECT AXIS SUB-TRANSIENT REACTANCE (SATURATED) Xd” DIRECT AXIS TRANSIENT REACTANCE (SATURATED) Xd’ DIRECT AXIS SYNCHRONOUS REACTANCE (SATURATED) Xd TOLERANCE ON REACTANCE MAXIMUM CONTINUOUS NEGATIVE PHASE SEQUENCE CURRENT (I2) MAXIMUM VALUE OF I22t

: : : : : : :

294.12MVA 250 MW 16.5 kV 10291 A 50 Hz 0.85 LAG 15.5%

:

22.8% 165%

: :

+ 15% 8%

:

10

GENERATOR TRANSFORMER PARAMETERS (CUSTOMER SCOPE) RATING IMPEDANCE VOLTAGE RATIO TAP CHANGER RANGE

: : : :

315MVA 14% + 10% TOL. AT PRINCIPAL TAP 420/ 16.5 kV + 5% TO –5%

UNIT AUXILIARY TRANSFORMER PARAMETERS (CUSTOMER SCOPE)

RATING IMPEDANCE VOLTAGE RATIO TAP CHANGER RANGE RATED HV SIDE CURRENT

: : : : :

20 MVA 10% + 10% TOL. AT PRINCIPAL TAP 16.5/6.9 kV + 10% TO –10% 699.839 A

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JPL, OP JINDAL SUPER TPP (4 X 250 MW) GENERATOR PROTECTION RELAY (GR1 & GR2) DEVICE NO. TYPE OF RELAY

A.

: :

GR1 & GR2 7UM62

GENERATOR BACK UP IMPEDANCE PROTECTION (21G1[GR1], 21G2[GR2])

IMPEDANCE OF GT (ZT)

CT RATIO VT RATIO

= =

14.0% 0.14 P.U.

=

0.14 ×

= = =

16.5 x16.5 OHM 315

0.121 OHM 12500 / 5 A

16500 / 3

V

110 / 3 IMPEDANCE ZONE Z1

= =

70% OF ZT CT RATIO 0.7 x Z × T VT RATIO

12500 110 / 3 × 5 16500 / 3

=

0.7 x 0.121 x

=

1.4114 OHM

SELECTED Z1

=

1.5 OHM

TIME DELAY OF ZONE Z1

=

1.00 SECOND (*)

IMPEDANCE ZONE Z2

=

100% OF ZT

=

Z

=

T

×

CT RATIO VT RATIO

0.121 x

12500 110 / 3 × 5 16500 / 3

=

2.008 OHM

SELECTED Z2

=

2.10 OHM

TIME DELAY OF ZONE Z2

=

2.00 SECOND (*)

*: TIME DELAY TO BE COORDINATED AT SITE WITH DISTANCE PROTECTION

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JPL, OP JINDAL SUPER TPP (4 X 250 MW) B.

UNDER VOLTAGE RELAY FOR 40G1 & 40G2 (27G1[GR1] & 27G2[GR2])

VOLTAGE SETTING RANGE TIME SETTING RANGE VOLTAGE SETTING TIME SETTING

: : : :

10.0 – 125.0V 0 – 60 SECOND 77V 10 SECOND

C. GENERATOR REVERSE POWER PROTECTION (32G [GR1] In case of a reverse power, the turbine set must be disconnected from the system as the turbine operation is not permissible without a certain minimum steam throughput (cooling effect) or, in case of a gas turbine set, the motor load would be too heavy for the network. For the primary test, the reverse power should be measured with the actual protection. The user should select a setting of 0.5 times the value of the measured motoring energy. This value can be found under the percentage operational measured values. The feature to correct angle faults of the current and voltage transformers should be used especially for very large machines with a particularly low motoring energy. The pickup value is set in percent of the secondary apparent power rating SNsec = √3 · UNsec · INsec If the primary motoring energy is known, it must be converted to secondary quantities using the following formula:

with Psec SNsec PMach SN, Mach UN Mach IN Mach UN prim IN prim

= = = = = = = = =

Psec = S N sec

Secondary power corresponding to setting value secondary nominal power = √3 · UNsec · INsec Machine power corresponding to setting value -0.5% of 250 MW = -1.25 MW Nominal apparent power of the machine = 294 MVA Nominal voltage of the machine = 165000 V Nominal current of the machine = 10291 A Primary Nominal Voltage of the voltage transformers = 165000 V Primary nominal current of the current transformer = 125000 A

− 1.25 ×16500 ×10291 294 ×16500 ×12500

SETTINGS SELECTED : RECOMMENDED POWER SETTING TIME SETTING (CLASS B) TIME SETTING (CLASS A)

=

: : :

-0.350%

-0.5% 2 SECONDS 10 SECONDS

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JPL, OP JINDAL SUPER TPP (4 X 250 MW) D.

GENERATOR LOW FORWARD POWER PROTECTION (37G [GR2])

The setting of the forward power protection depends strongly on the intended purpose. General setting guidelines are not possible. The pickup values are set in percent of the secondary apparent power rating SNsec = √3 · UNsec · INsec. Consequently, the machine power must be converted to secondary quantities:

with Psec SNsec PMach SN, Mach UN Mach IN Mach UN prim IN prim

= = = = = = = = =

Secondary power corresponding to setting value secondary nominal power = √3 · UNsec · INsec Machine power corresponding to setting value 0.5% of 250 MW = 1.25 MW Nominal apparent power of the machine = 294 MVA Nominal voltage of the machine = 165000 V Nominal current of the machine = 10291 A Primary Nominal Voltage of the voltage transformers = 165000 V Primary nominal current of the current transformer = 125000 A

Psec = S N sec

1.25 ×16500 ×10291 = 294 ×16500 ×12500

SETTINGS SELECTED : RECOMMENDED POWER SETTING TIME SETTING

0.350%

: :

0.5% 0 SECOND

TIME DELAY RELAY FOR 37G1 (SOFT TIMER-1 IN & GR2) TIME SETTING RANGE TIME SETTING

: :

0 – 5.0 SEC. 2.0 SECOND

TIME DELAY RELAY FOR 37G1 & 37G2 (SOFT TIMER-2 IN GR2) TIME SETTING RANGE TIME SETTING

E.

: :

0 - 50.0 SEC. 10.0 SECOND

GENERATOR FIELD FAILURE PROTECTION (40G1[GR1], 40G2[GR2])

CONDUCTANCE INTERSECT CHAR. 1 INCLINATION ANGLE OF CHAR. 1 CHAR. 1 TIME SETTING RANGE CONDUCTANCE INTERSECT CHAR. 2 INCLINATION ANGLE OF CHAR. 2 CHAR. 2 TIME SETTING RANGE CONDUCTANCE INTERSECT CHAR. 3 INCLINATION ANGLE OF CHAR. 3 CHAR. 3 TIME SETTING RANGE

: : : : : : : : :

0.25 – 3.00 50o – 120o 0 – 60 SECOND 0.25 – 3.00 50o – 120o 0 – 60 SECOND 0.25 – 3.00 50o – 120o 0 – 60 SECOND

TITLE : RELAY SETTING CALCULATIONS FOR GENERATOR RELAY PANELS

JPL, OP JINDAL SUPER TPP (4 X 250 MW)


Characteristic Curves The following figure shows the loading diagram of the synchronous machine in the admittance plane (P/U2; –Q/U2) with the statistic stability limit which crosses the reactive axis near 1/Xd (reciprocal value of the synchronous direct reactance).

Figure E-1 Admittance Diagram of Turbo Generators The underexcitation protection in the 7UM62 makes available three independent, freely combinable characteristics. As illustrated in the following figure, it is possible for example to model static machine stability by means of two partial characteristics with the same time delays (T CHAR. 1 = T CHAR 2). The partial characteristics are distinguished by the corresponding distance from the zero point (1/xd CHAR. 1) and (1/xd CHAR. 2) as well as the corresponding inclination angle α1 and α2 If the resulting characteristic (1/xd CHAR.1)/α1; (1/xd CHAR.2)/α2 is exceeded (in the following figure on the left), a delayed warning (e.g. by 10 s) or a trip signal is transmitted. The delay is necessary to ensure that the voltage regulator is given enough time to increase the excitation voltage.




Figure E-2 Stator circuit criterion: Pick–Up Characteristic in Admittance Diagram A further characteristic (1/xd CHAR.3 /α1 can be matched to the dynamic stability characteristic of the synchronous machine. Since stable operation is impossible if this characteristic is exceeded, immediate tripping is then required (time stage T CHAR 3). The primary setting values can be read out directly from the diagram. The related values must be converted for the protection setting. The same conversion formula can be used if the protection setting is performed with the predefined synchronous direct reactance.

with xdsec xd INMach UNMach UN, CTprim IN, CT prim

related synchronous direct reactance, secondary, mach related synchronous direct reactance of the machine = Nominal current of the machine = Nominal Voltage of the Machine = Primary Nominal Voltage of the voltage transformers = Nominal primary CT current =

1 x d sec

=

1 10291 16500 • • = 0.498 1.65 16500 12500

1.65 10291 A 16500 V 16500 V 12500 A

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multiplied by a safety factor of 1.05, the setting value of CHAR. 1 = 1.05 x 0.498 = 0.5229 with an angle of 80o. Time delay setting 2.0 Second. CHAR. 2 is set to 0.9 times CHAR. 1 = 0.9 x 0.5229 = 0.4706 with an angle of 90o. Time delay setting 2.0 Second. CHAR. 3 is set to 2 times CHAR. 2 = 2 x 0.4706 = 0.9412 with an angle of 100o. Time delay setting 0.3 Second.

F.

GENERATOR NEGATIVE SEQUENCE PROTECTION (46G1[GR1], 46G2[GR2])

SETTING RANGE NEGATIVE PHASE SEQ. CURRENT TRIP NEGATIVE PHASE SEQ. CURRENT ALARM TRIP DELAY ALARM DELAY NEGATIVE SEQUENCE FACTOR, Ksec TIME FOR COOL DOWN, tcooldown

with I2 max prim IN Machine IN CT prim

: : : : : :

10 - 100% 3.0 – 30% 0 – 60 SECOND 0 – 60 SECOND 2.0 – 100.0 SECOND 0 – 50000 SECOND

Permissible thermal inverse current of the motor Nominal current of the machine Primary nominal current of the current transformer

= =

Generator continuous negative phase sequence current capability

=

10291 A 12500 A

I 2 max prim I N Machine

= I2> (ALARM)

=

10291 8 ⋅ % 12500

I2>> (TRIP)

=

65% ⋅

=

65%

=

53.51% with time delay of 1.5 second

6.59% with time delay 20 second.

I N Machine I N CT prim

10291 12500

Negative sequence factor, Kprimary

Ksec

=

8%

I 2 max prim

=

(

=

10 second

=

Kprimary ⋅ (

=

⎛ 10291 ⎞ 10 ⎜ ⎟ second ⎝ 12500 ⎠

=

6.77 SECOND

I N Machine

)2 ⋅ t

I N Machine I N CT prim 2

)2

TITLE :




tcooldown

G.

=

(I

K primary

I N Machine )

2

2 max prim

=

10 second (0.08)2

=

1563 SECOND

GENERATOR DEAD MACHINE PROTECTION (50GDM1[GR1], 50GDM2[GR2])

CURRENT SETTING RANGE BASE MVA GENERATOR TRANSIENT REACTANCE (SATURATED) (Xd’) MAXIMUM VALUE OF Xd’ CONSIDERING TOL. GENERATOR TRANSFORMER IMPEDANCE MAXIMUM VALUE OF GT IMPEDANCE CONSIDERING TOLERANCE 400kV SYSTEM FAULT LEVEL

: = =

0.1 – 20.0 A 294 MVA 22.8%

= = = =

1.15×22.8 26.22% 14.0% 1.1×14.0%

= = = =

15.4% 40kA √3x40x400 MVA 27712 MVA

=

294 27712

= = = = = =

0.0106 P.U. 1/(0.154 + 0.0106 + 0.2622) 1/0.4268 2.343 P.U. 10291 A 10291 × 5

= = = =

12500 4.12 A 4.12 x 2.343 9.653 A (i.e. 234% of FLC of generator) 4.12 A

=

4.2 A

400kV SYSTEM IMPEDANCE AT 294MVA BASE

SHORT CIRCUIT CURRENT (P.U.)ISC GENERATOR CURRENT CT SECONDARY CURRENT CORRESPONDING TO 10291 A SHORT CIRCUIT CURRENT (IN AMP) HOWEVER, RELAY IS SET AT RATED FULL LOAD CURRENT OF GENERATOR RECOMMENDED CURRENT SETTING

TIME DELAY RELAY FOR FOR 50GDM1 & 50GDM2 (SOFT TIMER-TDPU IN GR1 & GR2) TIME SETTING RANGE TIME SETTING

: :

0.1 – 1.0 SEC. 1.0 SECOND

TIME DELAY RELAY FOR FOR 50GDM1 & 50GDM2 (SOFT TIMER-TDDO IN GR1 & GR2) TIME SETTING RANGE TIME SETTING

: :

0.1 – 1.0 SEC. 1.0 SECOND



H.


GENERATOR DEFINITE TIME OVERLOAD PROTECTION (51G1[GR1] & 51G2[GR2]) [USING CFC]

CURRENT SETTING RANGE TIME SETTING RANGE CT RATIO GENERATOR OUTPUT GENERATOR FULL LOAD CURRENT AT 95% OF RATED VOLTAGE CT SECONDARY CURRENT CORRESPONDING TO 10833.42 A GENERATOR OVERLOAD CAPABILITY CURRENT SETTING TIME SETTING CFC DIAGRAM IS SHOWN BELOW

: : : : = = = = : : :

0.10 – 20.0 A 0 – 60 SECOND 12500/5 A 250 MW 250 × 1000 3 × 16.5 × 0.95 x 0.85 10833.42 A

A

10833.42 x5 A 12500 4.33 A 10% FOR 3 MINUTES 4.77 A 25 SECOND

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JPL, OP JINDAL SUPER TPP (4 X 250 MW) I.

GENERATOR OVERVOLTAGE PROTECTION (59G1[GR1]) & 59G2[GR2])

The setting of limit values and time delays of the overvoltage protection depends on the speed with which the voltage regulator can regulate voltage variations. The protection must not intervene in the regulation process of the faultlessly functioning voltage regulator. For this reason, the two-stage characteristic must always be above the voltage time characteristic of the regulation procedure. VOLTAGE SETTING (DEF TIME TRIP) TIME SETTING (DEF TIMETRIP) VOLTAGE SETTING (INSTANTANEOUS) TIME SETTING (INSTANTANEOUS)

: : : :

132 V 1SEC 149 V 0.05 SEC

J.

VOID

K.

GENERATOR VT VOLTAGE SUPPLY SUPERVISION RELAY [60FL(VT1)[GR1] & 60FL(VT2)[GR2]]

RATED VOLTAGE NO SETTING IS REQUIRED ON THE RELAY

L.

:

110V

100% GENERATOR STATOR EARTH FAULT PROTECTION (64G[GR1])

SETTING RANGES/STEPS WARNING STAGE R< TRIPPING STAGE R<< CURRENT STAGE I>> 20 Hz VOLTAGE FAILURE SUPERVISION BLOCK U20< BLOCK I20< TRANSFORMER ANGLE ERROR CORRECTION CT ANGLE W1 TRIP DELAY ALARM DELAY SETTINGS TRANSFORMATION FACTOR, S/E/F -FACTOR

PICK UP VALUE OF THE WARNING STAGE OF STATOR EARTH FAULT PROTECTION TIME DELAY OF THE WARNING STAGE PICK UP VALUE OF THE TRIPPING STAGE OF STATOR EARTH FAULT PROTECTION TIME DELAY OF THE TRIPPING STAGE

: : :

20 – 700 OHM 20 – 700 OHM 0.02 – 1.50 A

: : :

0.3 – 15.0 V 5 – 40 mA -60 TO +60

: :

0 – 60 SECOND 0 – 60 SECOND

=

TRETr2 x (TRVD / TRICT)

= : :

TRETr TRANSFORMATION RATIO OF THE NGT = 16500/240 V TRVD TRANSFORMATION RATIO OF THE VOLTAGE DIVIDER = 500/200 V TRICT TRANSFORMATION RATIO OF THE INTERMEDIATE CURRENT TRANSFORMER = 600/5 A (16500/240)2 x [(500/200)/(600/5)] 98.458 10000/98.458 OHM

: : :

102 OHM (*) 10 SECOND 3000/98.458 OHM

: :

30.46 OHM 1 SECOND


JPL, OP JINDAL SUPER TPP (4 X 250 MW) NGT PERCENT IMPEDANCE NGT PRIMARY IMPEDANCE, R

PICK VALUE OF THE CURRENT TRIPPING STAGE S/E/F I>>

= =

5.0 P.U.

= =

182 OHM 0.2 × NGT PRIMARY VOLTAGE

16.5 2 × 0.05 0.075

= :

R 0.2 × 16500 5 x 600 182 0.15 A 1V

:

10 mA (*)

:

0 DEG (*)

=

PICK-UP THRESHOLD OF 20 Hz UNDER VOLTAGE BLOCKING PICK-UP THRESHOLD OF 20 Hz UNDER CURRENT BLOCKING ANGLE ERROR COMPENSATION OF EARTHING CT AND INERMEDIATE CT


x

1 TRICT

* : FINAL SETTINGS SHALL BE DONE DURING COMMISSIONING BASED ON PRIMARY TESTS TO BE CARRIED OUT AT SITE AS PER OPERATING INSTRUCTION OF THE RELAY.

M.

GENERATOR STATOR EARTH FAULT PROTECTION (64G1[GR1])

The criterion for the occurrence of an earth fault in the stator circuit is the emergence of a neutral displacement voltage. Exceeding the set value U0> therefore causes pickup for stator earth protection. Pickup value of earth fault detection =

=

(100% − 95%) ×VT SECONDARY VOLTAGE V 100% (100% − 95%) ×110 V 100%

= 5.5 V VOLTAGE SETTING

:

5.5 V

TIME SETTING

:

0.2 SECOND

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JPL, OP JINDAL SUPER TPP (4 X 250 MW) N.

GENERATOR STATOR EARTH FAULT PROTECTION (64G2[GR2])

The criterion for the occurrence of an earth fault in the stator circuit is the emergence of a neutral displacement voltage. Exceeding the set value U0> therefore causes pickup for stator earth protection. TRVD TRANSFORMATION RATIO OF THE VOLTAGE DIVIDER = 500/200 V Pickup value of earth fault detection =

(100% − 95%) × NGT SEC VOLTAGE / TR VD V 100%

(100% − 95%) × 240 × =

100%

200 500 V

= 4.8 V VOLTAGE SETTING TIME SETTING

O.

: :

4.8 V 0.2 SECOND

GENERATOR ROTOR EARTH FAULT PROTECTION (64R[GR1])

SETTING RANGES/STEPS WARNING STAGE RE< WARN AND RE
: : :

5 – 80 KOHM 1 – 10 KOHM 0.00 – 1.00mA

: : : : : :

0 – 60 SECOND 0 – 60 SECOND 40 KOHM 5 KOHM 10 SECOND 1 SECOND

: CHARGE Qc DURING POLARITY REVERSAL 0.02 mA (*) BELOW WHICH THE MEASURING CIRCUIT IS ASSUMED TO BE OPEN *: THE FINAL SETTING OF CHARGE Qc HAS TO BE DETERMINED DURING COMMISSIONING.

P.

UNDER FREQUENCY PROTECTION (81G1[GR1], 81G2[GR2])

By configuring the rated frequency of the power system and the frequency threshold for each of the stages f1 PICKUP to f4 PICKUP in each case the function is established as either overfrequency or underfrequency protection. Set the pickup threshold lower than nominal frequency if the element is to be used for underfrequency protection. FIRST STAGE – ALARM FREQUENCY SETTING RANGE(f1) TIME SETTING RANGE (t1) FREQUENCY SETTING (f1) TIME SETTING (t1) SECOND STAGE – CLASS C TRIPPING FREQUENCY SETTING RANGE(f2) TIME SETTING RANGE (t2) FREQUENCY SETTING (f2)

: : : :

40 - 66 Hz 0 - 600 SEC. 48.5 Hz 2.5 SECOND

: : :

40 - 66 Hz 0 - 100 SEC. 47.4 Hz

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: TIME SETTING (t2) 2.0 SECOND Q. GENERATOR DIFFERENTIAL PROTECTION (87G[GR1]) Pick up value of differential current, IDIFF> Time delay T IDIFF> Pick up value of high set trip, IDIFF>>

: : : :

0.1 I/IN Machine 0.00 SECOND

1 (I/IN Machine) X d' 1 (I/IN Machine) 0.228

Time delay T IDIFF>> Slope 1 of tripping characteristic Base Point of Slope 1 Slope 2 of tripping characteristic Base Point of Slope Pick up for Add-on stabilization

: : : : : : :

4.385 (I/IN Machine) 0.00 SECOND 0.15 0.00 (I/IN Machine) 0.5 0.00 (I/IN Machine) 4.00 (I/IN Machine)

Duration of Add-on stabilization

:

15 CYCLES

R.

GENERATOR OUT OF STEP (POLE SLIPPING) RELAY (98G1[GR1], 98G2[GR2])

CT RATIO, TRCT VT RATIO, TRVT

: :

12500/5 A

SOURCE IMPEDANCE (Zs)

: : = =

kV2/FAULT MVA 16.52/27712 0.00982OHM

Zd-Zc

=

GENERATOR POLE SLIPPING IMPEDANCE (ZG) Zb

= = = =

=

GENERATOR TRANSFORMER IMPEDANCE (ZT) Zc

= = = =

=

=

16500 110 V / 3 3

ZS ×

TRCT TRVT

0.00982 ×

12500 110 3 × 5 16500 3

0.1632 OHM 0.85 X 0.155 X 16.52/294 0.1220 OHM

ZG ×

TRCT TRVT

0.1220 ×

12500 110 3 × 5 16500 3

2.03293 OHM 0.14 X 16.52/315 0.121 OHM

ZT ×

TRCT TRVT

0.121×

12500 110 3 × 5 1 6500 3

2.01634 OHM




Figure Q1 : Polygonal Out-of-Step Characteristic with Typical Power Swings




Figure Q2 : Power swing polygon and impedance vectors with angle δ = Zb + Zc = 2.03293 + 2.01634 = 4.0492 OHM Ztot Za

=

0.289 x 4.0492 =

1.17 OHM

Measurement is enabled only if the positive sequence component of the currents has exceeded a minimum threshold 3502 I1> RELEASE (overcurrent pickup). Also because of the symmetry condition, a maximum value of negative sequence current 3503 I2< RELEASE must not be exceeded. I1> RELEASE = I2< RELEASE =

S.

120% IN GENERATOR 20% IN GENERATOR

GENERATOR TRANSFORMER OVER FLUXING PROTECTION (99GT1[GR1], 99GT2[GR2])

GENERATOR TRANSFORMER OVERFLUXING WITHSTAND CAPABILITY AND OPERATING TIME OF THE RELAY (INVERSE UNIT) ARE TABULATED BELOW: GENERATOR TRANSFORMER RELAY OPERATING TIME OVERFLUXING WITHSTAND CAPABILITY (INVERSE UNIT) VALUE TIME 1.10 2400 SECOND 36 SECOND 1.15 660 SECOND 16 SECOND 1.20 230 SECOND 9 SECOND 1.25 90 SECOND 5.76 SECOND 1.30 40 SECOND 4 SECOND 1.35 14 SECOND 2.94 SECOND 1.40 6 SECOND 2.25 SECOND U/f > PICKUP U/f > TIME DELAY U/f >> PICKUP U/f >> TIME DELAY

: : : :

1.10 10 SECOND 1.40 1 SECOND

TITLE :



JPL, OP JINDAL SUPER TPP (4 X 250 MW) GENERATOR INTERTURN FAULT PROTECTION (64GIT) DEVICE NO. TYPE OF RELAY

: :

64GIT 7SJ62

In case of single turn inter turn fault, unbalance produced in faulty phase leads to a voltage 0.939 p.u. in the faulty phase, with other two phase voltages being normal. Voltage across open delta secondary →

→

→

VOD = ( VR + VY + VB ) N, where, N is inverse of the transformation ratio of IVT1

⎜VOD ⎜

= N [V(0.883) + VCos 120° + jVSin 120° + VCos 240° + jVSin240°] = 0.939 V = VB = V = NV (0.939 - 0.5 + j 0.866 - 0.5 - j 0.866) = NV (0.939 - 1) = NV (- 0.061) = 0.061 V. N

IVT1 ratio

=

110

= = =

√3 √3 110/√3 V 0.061 x [110/√3] x [(80/√3)/(110/√3)] 2.72 V

VOD As VR VY VOD

V ⎜VOD⎜

80 =

1 N

IVT2 ratio is such so that relay at minimum setting is able to pick up on single turn fault and at the same time does not experience more than 200V IVT2 secondary is therefore chosen such that it does not reflect more than 200V for complete one phase of generator winding short circuited (there being no voltage from NGT secondary for inter turn faults). Under this condition, ⎜ VOD ⎜ = 1 x [110/√3] x [(80/√3)/(110/√3)] = 46.188 V Limiting values of open delta voltage are therefore 2.72 V and 46.188 V. IVT2 should step up open delta secondary voltage to more than relay pick-up value of 5.4 V but less than 200 V for a primary voltage of 46.188 V Choosing IVT2 secondary of 110V, the primary rating is = 110 x 46.188 200 = 25.4 V IVT2 ratio is 25.4/110 V.

TITLE :




This gives a voltage of [(110 x 2.72)/ 25.4] = 11.7V on a single turn fault which is sufficient to ensure positive operation of relay for a setting of 10V. VOLTAGE SETTING TIME MULTIPLIER SETTING

: :

10V 0.1

GENERATOR VT VOLTAGE SUPPLY SUPERVISION RELAY (60VT1, 60VT2, 60VT3 DEVICE NO. TYPE OF RELAY RATED VOLTAGE NO SETTING IS REQUIRED ON THE RELAY

: : :

60VT1, 60VT2 & 60VT3 MVAPM32 110V

: : :

97G VAA11 110V

GENERATOR ON RELAY (97G) DEVICE NO. TYPE OF RELAY RATED VOLTAGE NO SETTING IS REQUIRED ON THE RELAY

GRP GROUP 1 DC SUPPLY SUPERVISION RELAY (80G1) DEVICE NO. TYPE OF RELAY NO SETTING IS REQUIRED ON THE RELAY

: :

80G1 VAG11

GRP GROUP 2 DC SUPPLY SUPERVISION RELAY (80G2) DEVICE NO. TYPE OF RELAY NO SETTING IS REQUIRED ON THE RELAY

: :

80G2 VAG11




GENERATOR TRANSFORMER PROTECTION RTELAY – GTR2 (51NGT/ 87GT)

DEVICE NO. TYPE OF RELAY A.

: :

GTR1 7UT613

GENERATOR TRANSFORMER BACKUP EARTH FAULT PROTECTION (51NGT)

CURRENT SETTING RANGE, IE > TIME SETTING RANGE CT RATIO CURRENT SETTING, IE > TIME SETTING

0.25 – 175.00 A 0.0 – 60.0 SECOND 500/1 A 0.1 A 2.0 SECOND [TO BE GRADED WITH 400KV SYSTEM] THE ABOVE TIME SETTING SHALL BE CO-ORDINATED WITH LINE PROTECTION. [CUSTOMER MAY PLEASE ADVISE 220kV SIDE DISTANCE PROTECTION TIME SETTING]

B.

: : : : :

GENERATOR TRANSFORMER DIFFERENTIAL PROTECTION (87GT)

Pick up value of differential current, IDIFF> Time delay T IDIFF> Pick up value of high set trip, IDIFF>>

: : :


1 (I/IN GT) X d" 1 (I/IN GT) 0.14(0.9)

:

Selected Pick up value of high set trip, IDIFF>> Time delay T IDIFF>> Slope 1 of tripping characteristic Base Point of Slope 1 Slope 2 of tripping characteristic Base Point of Slope 2 Pick up for Add-on stabilization Duration of Add-on stabilization

7.9365 (I/IN GT) 10 (I/IN GT) 0.00 SECOND 0.20 0.20 (I/IN GT) 0.80 2.00 (I/IN GT) 4.00 (I/IN GT) 15 CYCLES

: : : : : : : : :

GENERATOR TRANSFORMER RESTRICTED EARTH FAULT PROTECTION (64RGT [GTR1] A. GENERATOR TRANSFORMER RESTRICTED EARTH FAULT PROTECTION (64RGT) DEVICE NO. TYPE OF RELAY CT RATIO RCT

: : : :

MAXIMUM FAULT CURRENT (HV SIDE)

:

64RGT 7SJ61 500/1A 5.0 OHM MVA × 1000 3 × HVVOLTAGE × Z(min.)

A

TITLE :




315 × 1000

= = =

FAULT CURRENT ON CT SECONDARY

3 × 420 × 0.14x0.9 3436.7095 A

3436.7095 ×

1 A 500

=

6.87 A

:

If (RCT + 2RL)

= =

NEGLECTING LEAD RESISTANCE 6.87 X5.0 34.35 V

VOLTAGE ACROSS THE RELAY UNDER THROUGH FAULT CONDITION

SET THE RELAY AT 5% 0F 1A SETTING CURRENT CURRENT REQUIRED FOR RELAY OPERATION VALUE OF STABILISING RESISTOR

: = =

0.05 A 0.05 A

VALUE OF STABILISING RESISTOR

= :

687 OHM 700 OHM

34.35 0.05

OVERALL DIFFERENTIAL PROTECTION RELAY – GTR3 ( 87OA)

DEVICE NO. TYPE OF RELAY Pick up value of differential current, IDIFF> Time delay T IDIFF> Pick up value of high set trip, IDIFF>>

: : : : : :

SELECTED IDIFF>> Time delay T IDIFF>> Slope 1 of tripping characteristic Base Point of Slope 1 Slope 2 of tripping characteristic Base Point of Slope 2 Pick up for Add-on stabilization Duration of Add-on stabilization

A

: : : : : : : : :

87GT 7UT635 0.1 I/IN Machine 0.00 SECOND

1 (I/IN OA) X d" 1 (I/IN OA) 0.14 x0.9 7.9365 (I/IN OA) 10.0 (I/IN OA) 0.00 SECOND 0.20 0.20 (I/IN OA) 0.80 2.0(I/IN OA) 4.00 (I/IN OA) 15 CYCLES

TITLE :




UNIT AUXILIARY TRANSFORMER PROTECTION RELAY UATAR1/ UATBR1 (50/51UAT, 64UAT) DEVICE NO. TYPE OF RELAY

A.

: :

UATAR1, UATBR1 7SJ61

UAT HV OVER CURRENT PROTECTION (50/51UAT)

CT RATIO LOAD ON 6.6kV UNIT BUS PRIOR TO STARTING OF BFP MOTOR STARTING CURRENT OF BFP MOTOR STARTING MVA OF BFP MOTOR

: :

800/1A 12.52 MVA*

= 2.8404 kA = sqrt(3) x 2.8404 x 6.6 = 32.47 MVA LOAD DETAILS ON 6.6kV UNIT BUS DURING STARTING OF BFP MOTOR ARE TABULATED BELOW (*): LOAD DESCRIPTION BASE LOAD PRIOR TO STARTING OF BFP MOTOR STARTING MVA FOR BFP MOTOR TOTAL MVA LOAD ON UAT DURING STARTING OF BFP MOTOR UT HV SIDE CURRENT

CT SECONDARY CURRENT CORRESPONDING TO 1470 A CURRENT SETTING TIME SETTING

MVA 12.52

COS φ 0.85

SIN φ 0.526

MW 10.64

MVAR 6.58

32.47

0.2

0.979 TOTAL

6.49 17.13

31.79 38.37

= = =

(17.13) 2 + (38.37) 2

= =

42.02 MVA 42.02 kA 3 × 16.5 1.4704 KA (1470x1)/800 A

= : :

1.8375 A 1.9 A 0.9 SECOND

*:

M/s JPL to check and confirm at their end, as Electrical System Design (JPL scope) has not been done by BHEL. Data indicated is from a similar 250MW project. However, exact loads on unit bus may vary based on rating of the drives & down stream LT loads.

B.

UNIT AUXILIARY TRANSFORMER RESTRICTED EARTH FAULT PROTN (64RUAT)

CT RATIO RCT

: :

MAXIMUM FAULT CURRENT (HV SIDE)

:

2000/1A 2.0 OHM MVA × 1000 3 × LVVOLTAGE × Z(min.)

=

FAULT CURRENT ON CT SECONDARY

= = =

20 × 1000 3 × 6.9 × 0.1 x 0.9 27892.13 A

18596 × 9.298 A

1 2000

A

A

TITLE :



JPL, OP JINDAL SUPER TPP (4 X 250 MW) VOLTAGE ACROSS THE RELAY UNDER THROUGH FAULT CONDITION

:

If (RCT + 2RL)

= =

NEGLECTING LEAD RESISTANCE 9.298 X2.0 18.59 V

SET THE RELAY AT 10% 0F 1A SETTING CURRENT CURRENT REQUIRED FOR RELAY OPERATION VALUE OF STABILISING RESISTOR

: = =

0.1 A 0.1 A

VALUE OF STABILISING RESISTOR

= :

185.9 OHM 250 OHM

18.59 0.1

UNIT AUXILIARY TRANSFORMER PROTECTION RELAY UATAR2/ UATBR2 (87UAT, 51NUAT)

A.

UNIT AUXILIAR TRANSFORMER DIFFERENTIAL PROTECTION (87UAT)

Pick up value of differential current, IDIFF> Time delay T IDIFF> Pick up value of high set trip, IDIFF>>

: : : :

Time delay T IDIFF>> Slope 1 of tripping characteristic Base Point of Slope 1 Slope 2 of tripping characteristic Base Point of Slope 2 2nd Harmonic content Cycle Time for Cross-blocking 2nd Harmonic 5th Harmonic content Cycle Time for Cross-blocking 5th Harmonic Limit IDIFFmax of 5th Harm.Restraint Pick up for Add-on stabilization Duration of Add-on stabilization Increase of Trip Char. During Start B.

: : : : : : : : : : : : : :


1 (I/IN UAT) X d" 1 (I/IN UAT) 0.09 11.11 (I/IN UAT) 0.00 SECOND 0.25 0.00 (I/IN UAT) 0.50 2.5 (I/IN UAT) 15% 3 CYCLE 30% 0 CYCLE 1.5 (I/IN UAT) 4.00 (I/IN UAT) 15 CYCLES OFF

UNIT AUXILIARY TRANSFORMER LV BACKUP EARTH FAULT PROTECTION (51NUAT)

CURRENT SETTING RANGE, IE > : 0.05 – 35.00 A TIME SETTING RANGE : 0.0 – 60.0 SECOND CT RATIO : 200/1 A : 0.05 A CURRENT SETTING, IE > : 2.0 SECOND TIME SETTING THE ABOVE TIME SETTING SHALL BE CO-ORDINATED WITH LINE PROTECTION. [CUSTOMER MAY PLEASE ADVISE 220kV SIDE DISTANCE PROTECTION TIME SETTING]

Generator Relay Settings

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