400kv Busbar Protection

SETTING RECOMMENDATION

APPLN 2012

For M/s. HVPNL LTD.

400KV BUSBAR PROTECTIONS

CONFIDENTIAL The information contained in this document is not to be communicated either directly or indirectly to any person not authorised to receive it.

SETTING CALCULATION FOR BUSBAR PROTECTION RELAYS 400KV BUSBAR PROTECTIONS CUSTOMER

:M/s HVPNL LTD

PROJECT

:400/220/66/33KV S/S AT FARIDABAD (NAWADA)

Prepared By

Sudheendra.K

Date

17.08.2012

Approved By

Sreenatha Rao. R.S.N.V

Revision

Rev.0

Page 1 of 6

GRID

400KV BUSBAR PROTECTION 1. SUBSTATION INFORMATION Settings and configuration of the P741 Numerical bus bar protection scheme is arrived based on the substation information provided by ALTOM SYSTEMS/HVPNL as detailed below. 2000 CTR - Primary of all feeders 1 CTR - Secondary of all feeders 2000 V CT knee Point for all feeders 15 Ohms CT resistance for all feeders 3000 A Maximum Load level in a feeder 245 A Minimum load current in a feeder 6 kA Minimum Short circuit level (ASSUMED) 40 kA Maximum Short circuit level 3000 A Maximum loading of 1 bar (ASSUMED) Two Main System Number of independent bars Maximum breaking time of CB

100 m sec (assumed 40msec breaker op. time + arcing time)

2. SETTING CRIETERIA OF MiCOM P741 – CENTRAL UNIT

6 values have to be entered in MiCOM P741 central unit Note: All values in CU is for base current of 2000A. 1.ID>1 (from 0.01 to 0.5 A (secondary value)) During normal operation the differential current in the scheme should be zero or negligible. Any abnormality is detected via a given threshold ID>1. This element is using for CT supervision. Recommended setting should be more than 2 % of maximum CT ratio and less than “Minimum Loaded feeder Current”. Recommended setting is 40 A. (NOTE : IF THE SPILL CURRENT IS MORE THAN 90A SHALL BE ADJUSTED AT SITE ACCORDINGLY) 2. Slope k1 setting range is from 0% to 50%. Recommended setting is 0% , as the minimum loading current is very less and CTs are of same ratio & similar magnetising characteristics.

FOR M/S. HVPNL - NAWADA 400KV BUSBAR PROTECTION, Rev-0

Page 2 of 6

M/S. ALSTOM T&D INDIA LTD, 19/1, G.S.T.ROAD, PALLAVARAM, CHENNAI - 600043.

3. Slope k2 setting range is from 20% to 90%, and recommendation is 65% , as the CTs are of same ratio & similar magnetizing characteristics and to provide stability for through faults. A trip is only permitted if this differential current exceeds the set slope of the bias characteristic. Recommended value for normal application is 65%. 4. Slope KCZ setting range is from 0% to 90%, it should be less than Icc min (1 bar) / (((Independent bar - 1) x IloadMax (1 bar)) + Icc min (1 bar)). Recommended setting is 30%. 5.ID>2 (from 0.5 to 30 A (secondary value)) as low as possible The main differential current element of MiCOM P741 will only be able to operate if the differential current reaches a threshold ID>2. In general, this setting will be adjusted above highest normal full load current in order to avoid mal operation even max loaded feeder CT fails. Normally recommended setting is more than 110 -180% of max load level. We shall choose ID>2, more than max loading considering (high instantaneous loading) and less than 50% of minimum short circuit level. Recommended setting is 2000*1.2= 2400 A 6.ID>1 Alarm Timer (from 100ms to 600 s) shall be greater than the longest protection time (such as line, over current, etc…) Recommended time delay is 5 secs. GROUP 1 DIFF BUSBAR PROT GROUP 1 Diff Phase Fault GROUP 1 CZ Parameters Phase Slope kcz 30.00% IDCZ>2 Current 2400 Amp GROUP 1 Zone Parameters Phase Slope k2 65.00% ID>2 Current 2400 Amp GROUP 1 Common Phase Slope k1 0.00% 40.00 Amp ID>1 Current ID>1 Alarm Timer 5.00 sec Diff Earth Fault Disable P741 Central unit blocking modes: GROUP1 Busbar Option: CZ circ flt mode Alarms Latched Zx circ flt mode Alarms Latched Circ flt reset time 60 secs Circ flt block mode Block / phase. Cz PU error Alarms Latched Zx PU error Alarms Latched 5 secs PU error timer 60 secs PU error reset time


Page 3 of 6


3.SETTING CRITERIA OF MICOM P743 – PERIPHERAL UNITS CT & VT RATIOS: For all feeders Phase CT Primary Phase CT Sec'y RBPh / RBN Power Parameters:For all feeders Standard Input Knee Voltage Vk RCT Sec'y Eff. Burden Ohm

2000 Amp 1 Amp --------(TO BE ENTERED AT SITE) British Standard 2000 V 15 Ohms ----------(TO BE ENTERED AT SITE)

NOTE: RBPh/RBn, Vk, Rct & Effective Burden values are very important to detect /confirm the CT Saturation condition. 4. CB Fail Protection: 50 LBB CB Fail: For all feeders I< (under current)

Recommended setting is 20% of CTR. The setting is 400 A.

Retrip timer TBF1/tBF3: A re-trip can be applied after a time tBF1/tBF3. Here we are issuing the retrip command after 50ms of main trip. CBF timer TBF2/tBF4: When both the local trip & retrip have failed, the countdown continues with a second timer adjusted to have a value of tBF2/tBF4. Recommended setting is “maximum breaking time of CB” + 100 msec. Recommended tBF2 & 4 setting is 200msec. GROUP 1 CB FAIL Control By I< Current Set for all feeders I> Status GROUP 1 Internal Trip CB Fail Timer 1 CB Fail Timer 2 GROUP 1 External Trip CB Fail Timer 3 CB Fail Timer 4 5. Dead Zone Protection: Dead Zone setting for all feeders:

I< 400 Disabled 50ms 200.0ms 50ms 200.0ms

Dead zone tripping is provided to sense the fault in-between CT and breaker when breaker is open. Dead zone setting shall be more than maximum loading & less than 80 % of the minimum fault current. Time delay of 50 m secs shall be given to avoid mal operation during arcing period, CB scattering during fault, where CB Open has been realised by PU. I>DZ Current setting I> DZ time delay


2400 50 m sec

Page 4 of 6

Amp


Group 1 Io supervision : Internal CT / AD converter of PU can be monitored by comparing the measured 3Io and derived neutral (IN =IR + IY + IB). Error co efficient shall be kept at 40% in order to detect internal CT (PU) failure. 40% Error factor KCE 5 secs Alarm delay 6A. SETTING SUMMARY FOR CENTRAL UNIT – P741 Group1 DIFF BUSBAR PROT Range/Options available Description Minimum Maximum Phase slope KCZ 0% 90% IDCZ>2 current 50A 30.0kA Phase slope K2 20% 90% ID>2 current 50A 30.0kA ID>1 current 10A 500A Phase slope K1 0% 50% ID>1 Alarm timer

100ms

600 s

Adopted Settings 30% 2400 65% 2400 90A 0% 5 secs

Remarks Check zone slope Check zone threshold Main zone slope Main zone threshold Circuitry fault pickup Circuitry fault slope Circuitry fault alarm delay

Group1 Busbar Option Range/Options available Minimum Maximum

Description

Adopted Settings

Remarks

CZ circ flt mode

Blocking latched, Alarms latched, self reset, Alarms Resetting mode Alarms latched & no block, Alarms SR & no block circuitry fault

Zx circ flt mode

Blocking latched, Alarms latched, self reset, Alarms Resetting mode of main Alarms latched & no block, Alarms SR & no block zones circuitry fault

Circuitry t reset

5s

600 s

60 s Blocking / phase

of

CZ

Circuitry fault reset time Blocking modes on circuitry fault

Circ block mode

Blocking/ phase , 3 phase block

CZ PU Error mode

Blocking latched, Alarms latched, self reset, Alarms Resetting mode Alarms latched & no block, Alarms SR & no block during CZ error

of

PU

Zx PU Error mode

Blocking latched, Alarms latched, self reset, Alarms Resetting mode of Alarms latched & no block, Alarms SR & no block during main zone error

PU

PU Error timer 2s 600 s PU Error reset 5s 600 s 6B. SETTING SUMMARY FOR PHERIPHAL UNIT – P743 Range/Options available Description Minimum Maximum CT, VT Ratios: Phase CT Primary


1A

30.0 kA

Page 5 of 6

5secs 60secs Adopted Settings

Alarm delay of PU error Reset time of PU error Remarks

2000 A for all CT Primary Rating feeders


Phase CT Secondary

1A

5A

1A

CT Secondary Rating

RBph/RBN

0.5

10

**

Ratio of Phase & neutral CT leads resistance

Standard Input

British Standard / IEC

British Standard

Knee Voltage Vk

20 V

5000 V

RCT Sec

0.1 Ω

50 Ω

Effective Burden ohm Group1 Dead Zone Protection:

0.1 Ω

200 Ω

Description I> DZ Current Set I> DZ Time Delay IN> DZ Current Set Group1 CB Fail: Description Control by I< CB Fail Timer 1 CB Fail Timer 2 CB Fail Timer 3 CB Fail Timer 4 Group1 Supervision: Description Error Factor Kce Alarm Delay Tce


2000 V for all CT Knee point Voltage feeders 15 Ohms forall CT sec resistance feeders **

Range/Options available Minimum Maximum 60 A 4800 A 0 sec 100 sec Enable/Disable

Adopted Settings

Range/Options available Minimum Maximum I<, 52a, I< & 52A 60 A 1200 A 0 sec 10 sec 0 sec 10 sec 0 sec 10 sec 0 sec 10 sec

Adopted Settings

Range/Options available Minimum Maximum 1% 100% 0 sec 10 sec

Page 6 of 6

CT Standard

Effective burden of lead

Remarks

2400 50 msec Disable

Remarks

I< 400 50 msec 200 msec 50 msec 200 msec Adopted Settings

Remarks

40% 5 sec


400kv Busbar Protection

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