report on status of state wise ufr & df/dt ... 132kv hanuman garh 1 48.8hz, inst. no ok yes yes...

REPORT ON STATUS OF

STATE WISE

UFR & df/dt RELAYS

IN NR GRID

CONTENTS

1 SUMMARY REPORT

2 STATE WISE STATUS

A) Rajasthan System

B) Uttar Pradesh System

C) Punjab System

D) DTL System

E) Haryana System

F) Uttrakhand System

G) Jammu & Kashmir System

H) Himachal Pradesh System

I) Chandigarh System

Summary Report: Under frequency and df/dt relays in NR Grid

INTRODUCTION:

The Under Frequency Load shedding (UFLS) scheme of Northern Region was reviewed before synchronisation of the NR-Central Grid. As decided in the meeting taken by Member (GO&D), on 5th July 2006, the three settings of UFRs in NR are 48.8, 48.6 and 48.2Hz. These settings were to be implemented w.e.f. 19-August 2006.

Accordingly, as recorded in OCC (Operation Coordination Committee) of NRPC, the State wise load relief of the flat UFR relays is as given below:

NR system State wise load relief-UFR Flat UFR Load Relief in MW States Peak-

MW met 2006-07

48.8Hz 48.6Hz 48.2Hz Total

Punjab 6558 180 220 250 650 Haryana 4201 110 140 150 400 Rajastan 4946 120 150 225 495

Delhi 3736 110 140 150 400 UP 7531 190 240 275 705

Uttarakhand 991 30 30 50 110 HP 873 20 20 75 115 J&K 1309 40 50 75 165

Chandigarh 247 0 10 0 10 TOTAL 30392 800 1000 1250 3050

df/dt relay settings: The df/dt settings were carried out for the individual regions separately in the past as a safety net of the respective Regions. A sub-group was constituted by the Operation Co-ordination Sub-Committee of OCC of the Northern Region Power Committee (NRPC) in its 9th meeting held on 15-Dec2006 to review the settings of df/dt relays, consisting of members from NRLDC,UPPCL,DTL,RVPNL & NRPC. Subsequently the OCC recommended the following settings of df/dt relays in the Northern Region. It was required to be ensured that the df/dt relays do not overlap the areas under flat UFRs as well as the SPS loads and identified manual load shedding. Accordingly the state wise load relief of the df/dt relays is as given below:

NR System df/dt relay operation Load relief in MW

States Peak MW

Met 2006-

07

Stage-I 49.9Hz&

0.1Hz/sec

Stage-II

49.9Hz &

0.2Hz/sec

Stage-III

49.9Hz &

0.3Hz/sec

Total

Punjab 6558 430 490 490 1410

Haryana 4201 280 310 310 900

Rajastan 4946 330 370 370 1070

Delhi 3736 250 280 280 810

UP 7531 500 280 280 1060

Uttarakhand 991 70 70 70 210

HP 873 50 70 70 190

J&K 1309 90 90 90 270

Chandigarh 247 0 50 50 100

TOTAL 30392 2000 2010 2010 6020

The settings in the existing df/dt relays were to be revised to obtain the desired relief by the constituents by 29th Feb 2008. The constituents who had to procure additional relays were required to commission same by May, 2008.

The NR system state wise combined load relief as per the flat and df/dt under frequency relays above are shown as under:

NR system state wise Total load relief with UFRs & df/dt relays in NR State Peak-

MW met 2006-07

Expected Flat UFR Load Relief (MW)

Total Expected Load Relief with df/dt relays (MW)

Expected combined Flat UFR and df/dt load relief (MW)

Punjab 6558 650 1410 2060 Haryana 4201 400 900 1300 Rajasthan 4946 495 1070 1565 Delhi 3736 400 810 1210 UP 7531 705 1060 1765 Uttrakahand 991 110 210 320 HP 873 115 190 305 J & K 1309 165 270 435 CHD 247 10 100 110 Total 30392 3050 6020 9070

After the grid disturbance incidents on 30th & 31st July 2012, NRPC vide their letter NRPC/OPR/105/07/ dated 22-08-2012, directed POWERGRID to assist the collection of information regarding UFRs and df/dt relays installed in the NR constituents.

Accordingly, a survey was conducted with visit to sites for collection of the field data of the 175 stations of constituents reported to be installed with UFRs and df/dt relays in NR systems of Rajasthan, UP, Punjab, Delhi, Haryana, Uttrakhand, J&K, HP and Chandigarh. The constituent wise numbers of stations audited from 23rd August 2012 to 3rd September 2012 are as follows:

Constituents Nos of Stns.



A: Rajasthan 50 D: Delhi 24 G: J & K 7

B: UP 30 E: Haryana 20 H: HP 3

C: Punjab 28 F: Uttrakahand 11 I: Chandigarh 2

During the process of gathering the field data it was observed that at a number of stations the UFRs and df/dt relays were either not installed or the settings were not as per the NRPC

recommendations. In a number of cases the UFRs and df/dt relays were found to be non-operative due to various reasons. The GPS time of operation was not available in the relays. The facility of relay operation data downloading for the analysis of the relay operations was also not available even for the newly installed UFRs and df/dt relays.

The following is the state wise summary report of the field data of UFRs and df/dt relays in the NR system:

A] Rajasthan System:

The status of Rajasthan system UFRs and df/dt operations during the July’12 grid disturbance incidents with NRPC recommended settings is as under: Sl NRPC recommended UFR & df/dt settings Expected load

relief (MW) Status of operation of UFRs and df/dt relays in Rajasthan system as per NRPC recommendations

1a UFR setting - 48.8Hz 120 Out of total 12 stns, the UFRs operated at 07 stns( Bhadra, Hanumangarh, Kotputli,132kV Bharatpur, Kuchaman, Mia Alwar, & Padampur). No operation at balance 5 stations.

1b UFR setting - 48.6Hz 150 Out of total 3 stations, UFR at one stn operated (Kekri) & No-operation took place at balance 2 stations.

1c UFR setting - 48.2Hz 225 Setting not implemented

2a df/dt Stg-1 freq 49.9 Hz Slope 0.1Hz/sec 330 1 No df/dt relay operated at 220KV Bharatpur.

2b df/dt Stg-2 freq 49.9 Hz Slope 0.2Hz/sec 370 Out of total 4 stations df/dt relay operated at 1 station(Sujangarh,) & no operation at balance 3 stations.

2c df/dt Stg-3 freq 49.9 Hz Slope 0.3Hz/sec 370 Out of 5 stations, df/dt operated at 4 stns(Bali, Nagaur, Chomu & Hindaun) on 30th & 31st July’12 and 1 station(Bhinmal) df/dt operated only on 31-07-12.

Total

UFRs- 495

Df/dt- 1070

UFRs relief (30th / 31st ): 52 / 38 MW

Df/dt relief (30th / 31st ): 175 / 153 MW

The load relief data is as assessed and recorded in log sheet or gathered from field survey is attached as annexure-A for various constituent stations

Status of Rajasthan Station where UFRs & df/dt relays were declared installed to NRPC Sr. No.

Name of Substation

Nos of UF relays at Stn

FLAT UFR Setting (Hz),Inst. Or Time delay

Df/dt Setting Hz (Hz/sec),Inst./Time delay

Status of Power Supply

Operation on 30.07.12


1 220 KV Bharatpur 2 No 49.9Hz, 0.1Hz/s, Inst.

OK Yes Yes

2 220 kv Sujangarh 2 No 49.9Hz, 0.2Hz/s, Inst.

OK Yes Yes

3 220 kv Nagur 2 No 49.9Hz, 0.3 Hz/s, Inst.

OK Yes Yes

4 220 kv Bali 2 47.8Hz, Inst.

49.9Hz, 0.3Hz/s, Inst.

OK Yes Yes

5 220 kv Chomu 2 48.8Hz, ∆t:0.04s


OK Yes Yes

6 220 kv Hinduan 2 48.8Hz, Inst.


OK Yes Yes

7 220 kv Kotpulti 3 48.8Hz, Inst.


OK Yes Yes

8 220 kv Kuchman 2 48.8Hz, Inst.

49.9Hz,0.2Hz/s,Inst.

OK Yes Yes

9 132 kv Bhadra 1 48.8Hz, Inst.

No OK Yes Yes

10 132 kv Bharatpur 1 48.8Hz, Inst.

No OK Yes Yes

11 132 kv Bherunda 1 No No OK *Yes *Yes

12 220 kv Dausa 2 No No OK *Yes *Yes 13 132 kv

Govindgarh 1 No No OK *Yes *Yes

14 132kv Hanuman garh

1 48.8Hz, Inst.

No OK Yes Yes

15 132 kv Kekri 1 48.6Hz, Inst.

No OK Yes Yes

16 220 kv Mia Alwar 1 48.8Hz, Inst.

No OK Yes Yes

17 132 kv Newai 1 No No OK *Yes *Yes

18 220 KV Padampur 1 48.8Hz, Inst.

No OK Yes Yes

19 132 kv Renwal 1 No No OK *Yes *Yes

20 132 KV Weir 1 No No OK *Yes *Yes

21 132 kv Deedwana 1 No No OK *Yes No

22 132 kv Makrana 1 No No OK *Yes No

23 220 kv Bhinmal 2 No 49.9Hz, 0.2Hz/s, Inst.

OK No Yes

24 132 kv Jhunjhunnu

1 No No OK No *Yes

25 132 kv Shahpura 1 No No OK No *Yes

26 220 kv Alwar 1 48.8Hz, Inst

No OK No No

27 132 kv Bagar 1 48.6Hz, Inst.

No OK No No

28 132 kv Bagru 1 48.6Hz, Inst.

No OK No No

29 220 kv Balotra 2 No 49.9Hz, 0.1Hz/s, Inst.

OK No No

30 132 kv Bhansur 1 48.8Hz, Inst.

No OK No No

31 220 kv Bilara 2 48.8, Inst. 49.9Hz, 0.1Hz/s, Inst.

OK No No

32 132 kv Dechu 1 48.8Hz, Inst.

No OK No No

33 132 kv Phulera 2 No 49.2Hz, 0.2Hz/s, Inst.

OK No No

34 132 kv Fatehpur 1 48.8Hz, Inst.

No OK No No

35 132 kv Merta 1 48.6Hz, ∆t:0.04s

No OK No No

36 220 kv Pindwara 1 47.7Hz, Inst.

No OK No No

37 132 kv Rajisar 1 48.8Hz, Inst.

No OK No No

38 220 kv Sikar 1 48.8, 48.2,47.9,47.0Hz, Inst.

No OK No No

39 220 kv Sirohi 1 47.7Hz, Inst.

No OK No No

40 132 kv Thanagaji 1 48.8Hz, Inst.

No OK No No

41 220 kv Tinwari 1 48.7Hz, Inst.

No OK No No

42 220 kv Reengus 1 No No Not Commissioned

No No

43 132 kv Sultana 1 No No Relay Defective

No No

44 132 kv Kankroli 0 NA NA NA No No

45 220 kv Khetri Nagar

0 NA NA NA No No

46 132 kv Neemkathana

0 NA NA NA No No

47 220 kv Ratnagarh 0 NA NA NA No No 48 132 kv Sardhana 0 NA NA NA No No

49 132 kv Sriganganagar

0 NA NA NA No No

50 220 kv Dhod 0 NA NA NA No No

• Relays are presently being used for rotational load shedding where UFR and df/dt col. indicated No / No

From the above it can be summarized as follows: At 7 stations (Dhod, Kankroli, Khetrinagar, Neem-ka-thana, Ratangarh, Sardana, & Sriganganagar where no UFRs were installed and at another 2 stations i.e.Rengus the UFR was not commissioned and at Sultana relay was found defective. At 16 stations(Alwar, Bagar,Bagru, Balotra, Bhansur, Bilara, Dechu, Phulera, Fathehpur, Merta, Pindwara, Sirohi, Rajisar, Sikar, Thanagaji & Tinwari) the UFRs were installed but did not operate. A total of 15 numbers of UFR & df/dt relay out of 50 locations operations took place in Rajasthan system as mentioned in the table above at recommended frequency settings. In addition the RLSS UF relays at 10 stations. Out of these, 6 stations ( Bheruanda, Dausa, Govindgarh, Newai, Renwal, & Weir) operated during both grid incidents while at 4 stations operated on 1 incident each i.e. at Deedwana & Makrana RLSS UF relays operated on 30-07-12 & Jhunjunu & Shahpura on 31-07-12 only.

B] Uttar Pradesh System:

The status of UFRs and df/dt operations during the July’12 grid disturbance incidents with NRPC recommended settings in the UP system is as under:

Sl NRPC recommended

UFR & df/dt settings Expected load relief (MW)

Status of operation of UFRs and df/dt relays in UP system as per NRPC recommendations.

1a UFR setting - 48.8Hz 190 No relay operation took place at 06 stations.

1b UFR setting - 48.6Hz 240 02 stations relays operated.(Chinnat & 220kVSarojini nagar) & not operated at balance 2 stations.

1c UFR setting - 48.2Hz 275 No relay operated at 02 stations.

2a df/dt Stg-1 freq 49.9 Hz Slope 0.1Hz/sec

500 Setting not implemented

2b df/dt Stg-2 freq 49.9 Hz Slope 0.2Hz/sec

280 Only 1 operated at Najibabad on 31-07-12. This did not operate on 30-07-12 GD incident. Not operated at balance 1 station for this setting.

2c df/dt Stg-3 freq 49.9 Hz Slope 0.3Hz/sec

280 No relay operation at all the 02 stations.

Total

UFRs- 705

df/dt- 1060


df/dt relief (30th / 31st ): 0 / 7 MW

Status of UP Stations where UFRs & df/dt relays were declared installed to NRPC Sr. No.

Name of Substation







1 220 kv Muradnagar

1 48.2, ∆t:0.15s 48.8, 0.2 Hz/s OK Yes Yes

2 220 kv CB Ganj 1 48.8, ∆t: 0.6s No OK Yes Yes

3 220 kv Chinnat 1 48.6Hz ,Inst. No OK Yes Yes

4 220 kv Sarojni nagar

1 48.6,Inst. No OK Yes Yes

5 132 kv Najibabad 2 48.8, ∆t:0.15 s 49.9, 0.2 Hz/s OK No Yes 6 220 KV

Sahibabad 1 48.2, ∆t: 0.15s 49.9, 0.4 Hz/s OK No Yes

7 220 kv Saharanpur

1* 48.0, Inst. 48.5, 0.6 Hz/s *Not operational

No No

8 220 kv Panki 1* 48.6, ∆t: 0.15 s 49.6, 0.3 Hz/s *Not operational

No No

9 220 kv Nara 1 47.8, Inst. 49.9, 0.2 Hz/s OK No No 10 132 kv Lalukheri 1 48.8, Inst. 49.9Hz 0.3

Hz/s OK No No

11 Khurja 1 48.8, 48.3,48.2, ∆t:0.15s

49.9Hz, 0.2Hz/s

NA No No

12 220 kv Modipuram

1 48.2, Inst. 49.9Hz,0.3 Hz/s

OK No No

13 220 kv Firozabad 0 No No NA No No

14 400 kv Sarojni nagar

0 No No NA No No

15 220 kv Sultanpur 0 No No OK No No

16 132 kv Gazipur - I 0 No No NA No No

17 132 kv Kasganj 0 No No NA No No

18 220 kv Etah 0 No No NA No No 19 132 kv Aurai 0 No No NA No No 20 220 kv Barut 1* No No *NO No No

21 132 kv Saidpur 1* 48.8,Inst. No *NO No No 22 132 kv Rampur 1 48.8, ∆t: 0.15s No OK No No 23 132 kv Kauri ram 1* 48.8, Inst. No *NO No No 24 132 kv Philibhit 1 48.8, Inst. No NA No No 25 132 kv Rasra 1* 48.8, 48.6, Inst. No *NO No No 26 220 kv Sonik 1 48.8 Inst. No OK No No 27 220 kv Reewa

Road 1* 48.6,Inst. No *NO No No

28 132 kv Kunda 1* 48.4, ∆t: 0.15s No *NO No No 29 132 kv

Bhupiamau 1* 48.4, ∆t: 0.15s No *NO No No

30 132 kv Kerakat 1* 48.2, Inst. No NA No No

*Not Operational From the above table, it can be summarized as follows: A total of 3 numbers of UFR & df/dt relay operations took place in UP system at recommended frequency settings out of the total 30 stations and could not enable the target combined load relief of 1765MW during each grid disturbance incidents. At 7 stations of UP there were no UFRs installed.(Aurai, Gazipur-1, Kasganj, Etah, Firozabad, Sultanpur & 400kV Sarojininagar). At 3 stations (CB Ganj, Najibabad & Shibabad UFR & df/dt Relays operated through RLSS. At another 17 stations the UFRs were not operationed (Saharnpur, Panki, Nara, Lalukheri, Khurja, Modipuram, Barut, Saidpur, Rampur, Kauriram, Pilibhit, Rasra, Sonit, Reva road, Kunda, Bhupiamau & Kerakat).

C] Punjab System:

The status of Punjab system UFRs and df/dt operations during the July’12 grid disturbance incidents with NRPC recommended settings is as under: Sl NRPC recommended UFR &

df/dt settings Expected load relief (MW)

Status of operation of UFRs and df/dt relays in Punjab system as per NRPC recommendations.

1a UFR setting - 48.8Hz 180 Out of total 4 stations at 02 stations UF relays operated.(Barnala & Wadalgranthi) & did not operate at balance 2 stations.

1b UFR setting - 48.6Hz 220 Setting not implemented 1c UFR setting - 48.2Hz 250 At all the 3 stations relays have operated (Jalandhar and

Jamalpur on both incidents & Sangrur only on 30-07-12) 2a df/dt Stg-1 freq 49.9 Hz Slope

0.1Hz/s 430 Setting not implemented


490 Not operated at 1 station(Jamalpur)


490 Not operated at 1 station(Rajpura)

Total

UFRs- 650

df/dt- 1410

UFRs relief (30th / 31st ): 297 / 267MW


Status of Punjab Stations where UFRs & df/dt relays were declared installed to NRPC Sr. No.

Name of Substation



Df/dt Setting Hz (Hz/sec),Inst./ Time delay




1 220 kv Barnala 1 48.8 Hz,Inst No OK Yes Yes

2 220 kv Wadala Granti

1 48.8Hz,Inst. No OK Yes Yes

3 220 kv Sangrur 1 48.2Hz,Inst. No OK Yes No

4 220 kv Jalandar BBMB

1 48.2Hz,Inst. No OK Yes Yes

5 220 kv Jamalpur BBMB

2 48.2Hz,Inst 49.9Hz/s,0.2Hz/s,Inst.

OK Yes Yes

6 220 kv Jamsher 1 No 48.8 Hz,0.2 Hz/s,Inst.

OK Yes Yes

7 132 kv Hosiharpur 1 No 48.8 Hz,0.3 Hz/s,Inst.

OK Yes Yes

8 132 kv Banga 1 48.8 Hz,∆t-0.15s

No OK Yes Yes

9 132 kv Bhogpur 2 48.8 Hz,∆t-0.1s

No OK Yes Yes

10 132 kv Doraha 1 48.59Hz, ∆t-0.15s

No OK Yes Yes

11 220 kv Goraya 1 48.2Hz,∆t-0.05s

No OK Yes Yes

12 220 kv Sultanpur 1 No 48.8Hz,0.1 Hz/s,Inst

OK Yes No

13 220 kv Almoh 1 48.8Hz,Inst No OK No No

14 220 kv Dhandari 1 48.21Hz, Inst No OK No No 15 132 kv Ropar 1 48.8Hz, Inst. No OK No No

16 220 kv Rajpura 1 No 49.9Hz,0.3Hz/s,Inst

OK No No

17 220 kv Gobindgarh – 1

1 No No NA No No

18 220 kv Bhutari 0 NA NA NA No No

19 132 kv Samad bhai

0 NA NA NA No No

20 132 kv Bagh Purana

0 NA NA NA No No

21 132 kv Dharamkhot

0 NA NA NA No No

22 132 kv Malout 0 NA NA NA No No

23 220kv Patiala-Patran

0 NA NA NA No No

24 220 kv Sunam 0 NA NA NA No No

25 220 kv Dhuri 0 NA NA NA No No 26 132 kv Kotakpura 0 NA NA NA No No

27 220 kv Patti 0 NA NA NA No No

28 220 kv Jagraon 0 NA NA NA No No

From the above it can be summarized as follows:

At total 5 numbers of substations, UFR & df/dt relays operation took place in Punjab system at recommended frequency settings out of the total 28 stations and could not enable the target combined load relief of 2060MW during each grid disturbance incidents.

Additional time delays were set from 50-150ms at 48.8 & 48.2Hz for the flat UFR relays for which the exact time of tripping during the disturbance could not be ascertained in absence of the non availability of GPS time and data downloading facility in the relay.

D] Delhi System:

The survey of DTL substation was conducted from 23.08.2012 to 30.08.2012 and total of 24 substations were covered. All substations are 220 KV except Rohtak Road which is 66KV substation under control of NDPL. The 220KV Rajghat S/S is also reported to be independent of DTL and in premises of Rajghat Power Station. All other substations are controlled by DTL and Under Frequency relays used at these S/Stns are maintained by DTL.

At all the substations, under frequency relay SPAF 340-C3 of ABB make is used. At Rajghat substation in addition to the ABB make SPAF 340-C3 relay used in 04 feeders, another ABB make relay RXFE -4 is also used for two feeders. The ABB make relay SPAF 340-C3 is with four under frequency elements which can be set for U/F or df/dt function used for 04 independent outputs (O/P). There is no separate df/dt relay used at any substation. At most of the substations one O/P is used for df/dt function. However, out of total 24 stations df/dt function is configured in 16 stations in DTL system.

One number flat under-frequency operation output is set for very low value, generally less than 48Hz. The operation of this flat frequency setting is scheduled to trip all the X, Y and Z group feeders ( Flat) through the PLC unit of the RLSS. The tripping from this is irrespective of the set rotational schedule in the PLC unit.

The Rotational Load Shedding Scheme has been used with the distribution feeders which are divided into three groups viz X, Y & Z for purpose of under frequency load shedding. There are some essential loads (feeders) which are kept out of U/F load shedding by DTL. The other two outputs are used for flat under frequency RLSS operation as per the set schedule of rotational load shedding system (RLSS) for tripping X or Y or Z group of feeders through programmable logic control (PLC) unit. The RLSS PLC operates on 24V DC or 230V AC supply using different kind of power supply module in each case. At some of the S/S the PLC was out due to unhealthy power supply/ faulty UPS of the PLC unit.

The df/dt relay operation was evident at 2 stations only where all the X,Y & Z Groups were indicated to be recorded with UF Relay operation codes.During the grid incidents the X,Y&Z groups tripped party at both these stations of Shalimar bagh & Park street except on 30-07-12 on which X,Y&Z groups tripped at Shalimar bagh. The wiring TB fuse at Park Street for the 33KV Motia Khan feeder was found to be blown off. The exact time and initiating UF element causing the tripping could not be ascertained in absence of GPS time and the relay operation codes for the four elements which were generally missing in the operation records at the stations other than Park Street and Shalimar Bagh stations. The facility for data downloading from the SPAF relays was not available. The actual load relief at various frequencies as per NRPC setting in the four elements (including the two RLSS elements) could not be ascertained in view of above.

The status of UFRs and df/dt relay operations during the July’12 grid disturbance incidents with NRPC recommended settings is as under:

Sl NRPC recommended UFR & df/dt settings

Expected load relief (MW)

Status of operation of UFRs and df/dt relays in Delhi system as per NRPC recommendations.

1a UFR setting - 48.8Hz 110 Setting not implemented

1b UFR setting - 48.6Hz 140 Setting not implemented

1c UFR setting - 48.2Hz 150 05 stations operative (Sarita Vihar, Geeta Colony,Kashmeri Gate , Rajghat & South of Wazirabad with time delay 0.15s).




280 Out of total 5 stations the df/dt relay at 1 station operated(Shalimar Bagh) No df/dt relay operated at balance 4 stations for this setting.


280 Out of total 3 stations df/dt operated at 1 station( Park street-49.0Hz). No df/dt relay operated at balance 2 stations for this setting.

Total

UFRs- 400

df/dt- 810



It is obvious from the above that only 5nos. flat UFRs and 2nos df/dt relays operated in DTL system. Additional time delays were set between 150-300ms in these relays and exact timing of the load relief during the disturbance could not be ascertained in absence of UF relay data downloading facility. Thus total of 7 numbers of UFRs & df/dt relay operations took place in DTL system at recommended frequency settings out of the total 24 stations and could not enable the target combined load relief of 1210MW during each grid disturbance incidents.

Status of Delhi Stations where UFRs & df/dt relays were declared installed to NRPC

Sr. No.

Name of Substation




RLSS power supply




1 Shalimar Bagh

1 47.9Hz,Δt-

0.15s 49.9Hz,0.2Hz

/s,Δt-0.3s 24 V DC OK df/dt trip:

X,Y,Z df/dt trip : X,Y(partly),Z trip

2 Park Street 2 47.8Hz,Δt-

0.15s 49.0Hz,0.3 Hz/,Δt-0.15s

24 V DC OK* df/dt trip: Grp-X,Y,Z (partly)

df/dt trip: Grp-X,Y,Z (partly)

3 Rajghat 2 48.2,48.0,47.7Hz,Δt-0.15s

No PLC not used

NA Flat UFR trip: X,Y, Z

Flat UFR trip: X,Y, Z

4 South of Wazirabad

1 48.2Hz,Δt-

0.15s 49.0Hz,0.2Hz/s,Δt-0.15s

24 V DC OK Flat U/F trip: X, Y, Z trip

Flat U/F trip: X, Y, Z trip

5 Patparganj 2 48.0,47.7Hz,Δt-0.15s

No 24 V DC OK Flat UFR trip:X, Y(partly), Z

Flat U/F trip: X(partly), Y(partly), Z(partly) trip

6 Papankalan 1 47.9Hz,Δt-

0.15s 48.1Hz,0.4Hz/s,Δt-0.150s

230V AC thro inverter

OK RLSS trip:Grp-X(partly)+Z(partly)

RLSS trip: Grp-X (partly) + Z(partly)

7 Geeta Colony

1 48.2,48.3Hz,Δt:-0.15s

No 24 V DC OK RLSS trip : Grp X & Z

RLSS trip : X,Y ,Z tripped

8 Sarita Vihar 2 48.2Hz,Δt-

0.15s 49.2Hz,0.2 Hz/s,Δt-0.15s


Fail RLSS trip: Grp-Z

RLSS trip: Grp-Z

9 Najafgarh 1 47.7Hz,Δt-

0.15s 49.9Hz,0.2Hz/s,Δt-0.3s


OK RLSS trip: X trip

RLSS trip: X trip

10 Mehrauli 1 47.6 Hz, Δt:

150 msec 48.2Hz,0.3Hz/s,Δt-0.15s

24 V DC OK RLSS trip: Grp-X

RLSS trip: Grp-X

11 Kashmere Gate

1 47.8,48.2Hz,Δt-0.15s

No 24 V DC OK** No tripping Flat U/Ftrip: Grp- X,Y, Z

12 Gazipur 1 47.2 Hz, Δt:

150 msec 49.9 Hz,0.2Hz/s,Δt-0.15s

24 V DC OK** No tripping No tripping

13 Gopalpura 1 47.6HzΔt-

0.15s

49.9Hz,0.3Hz/s,Δt-0.15s


14 IP Extension

1 47.7 Hz, Δt:

150 msec No 230V

AC thr’ inverter

OK** No tripping No tripping

15 IP Station 1 48.2,48.0Hz,Δt-0.15s

No 24 V DC OK** No tripping No tripping

16 Kanjhawal 1 48.2Hz,Δt-

0.15s 49.2 Hz,0.2Hz/s,Δt-0.15s

24 V DC fail No tripping No tripping

17 Lodhi Road 1 47.8Hz,Δt-

0.15s 49.9Hz,0.2Hz/s

230 V AC

fail No tripping No tripping

18 Narela 1 47.6Hz,Δt-

0.5s 49.9Hz,0.2Hz/,Δt-0.3s

24 V DC fail No tripping No tripping

19 Nariana 1 47.7Hz,Δt-

0.15s 49.9Hz,0.3Hz/s,Δt-0.15s



20 Okhla 1 47.9Hz,Δt-

0.15s 49.0Hz,0.3Hz/s,Δt-0.15s


21 Rohini 1 47.9Hz,Δt-

0.15s 49.2 Hz, 0.2 Hz/sec, Δt:

150 msec


22 Rohtak Road

1 48.2Hz,Δt-

0.15s No 24 V DC fail No tripping No tripping

23 Sabzi Mandi 1 48.2,47.9Hz,Δt-0.15s

No 230V AC thro inverter

fail No tripping No tripping

24 Vasant Kunj 1 47.8Hz,Δt-

0.15s

49.0 Hz,0.2Hz/c,Δt-0.15s



** Possible auxiliary supply to PLC unit on a/c of back-up UPS battery problem at the time of disturbance. From the above table, it can be summarized as follows: No relay operated at 13 stations – Gazipur, Gopalpura, IP Extension, IP Station, Kanjhawal, Lodhi Road, Narela, Nariana, Okhla, Rohini, Rohtak Road, Sabzi Mandi & Vasant Kunj The 4 nos of UFRs operated under the Rotational Load Shedding Scheme(RLSS) at 4 stations took place in Delhi system during July’2012 grid disturbance incidents are as under:

• 48.0 & 47.6, 47.7 Hz ∆t=150ms: Operated at 3 stations (Mehrauli & Najafgarh-X, Patparganj-X+Z)

• 47.9Hz Time delay 150ms: Operated at 1station (Papankalan-X+Z partly )

E] Haryana System:

The status of Haryana system UFRs and df/dt operations during the July’12 grid disturbance incidents with NRPC recommended settings is as under: Sl NRPC recommended UFR & df/dt settings Expected load

relief (MW) Status of operation of UFRs and df/dt relays in Haryana system as per NRPC recommendations

1a UFR setting - 48.8Hz 110 Operation at 01 station- Nission only on 31st July’12.


1c UFR setting - 48.2Hz 150 Operated at 1 stn (Shahbad-48.6Hz, ∆t- 0.15s)

2a df/dt Stg-1 freq 49.9 Hz Slope 0.1Hz/sec 280 Setting not implemented

2b df/dt Stg-2 freq 49.9 Hz Slope 0.2Hz/sec 310 Out of total 8 stations, df/dt relays at 03 stations operated (Dadri-BBMB, Dhulkot & BBMB-Hissar) No relay operation at balance 5 stations.

2c df/dt Stg-3 freq 49.9 Hz Slope 0.3Hz/sec 310 Out of total 4 stations, relay at 02 stations operated (Palwal & Sirsa) No relay operation at balance 2 stations.

Total

UFRs- 400

df/dt- 900

UFRs relief (30th / 31st ): 55 / 35MW

df/dt relief (30th / 31st ): 412/ 129 MW

Status of Haryana Station where UFRs & df/dt relays were declared installed to NRPC is as under:

Sr. No.

Name of Substation



Df/dt Setting Hz (Hz/sec),Inst./ Time delay




1 220 kv Dadri BBMB 1 48.2Hz,

∆t:0.5s 49.9Hz, 0.2Hz/s,Inst.

OK Yes Yes

2 220 kv Dulkote BBMB

1 No 49.9Hz, 0.2Hz/s,Inst.

OK Yes Yes

3

220 kv Hisar BBMB 2 48.6Hz, ∆t:0.5s & 48.2Hz, ∆t:0.15s

49.9Hz, 0.2Hz/s,Inst.

OK Yes Yes

4 220 kv Jagdhari BBMB

1 No 49.9Hz, 0.2Hz/s,Inst.

OK Yes Yes

5 220 kv Palwal 2 48.2Hz,

∆t:0.1s 49.9Hz, 0.3Hz/s, Inst.

OK Yes Yes

6 220 kv Shahbad 1 No 49.9Hz,

0.2Hz/s,Inst. OK Yes Yes

7 220 kv Sirsa 1 48.8Hz,

∆t:0.16s 49.9Hz, 0.3Hz/s, Inst.

OK Yes Yes

8 220 kv Nissing 1 48.8Hz, Inst. 48.8Hz,0.2

Hz/s,Inst. OK No Yes

9 220 kv Badshahpur 1 No 49.9Hz,

0.3Hz/s, Inst. OK No No

10 220 kv Hisar IA 2 48.61Hz,

∆t:5.1s No OK No No

11 220 kv Kaithal 1 No 49.9Hz, 0.4Hz/s,Inst. OK No No

12 220 kv Karnal 2 No No OK No No

13 220 kv Kurushetra 1 No 49.9Hz,0.2Hz/s,Inst. OK No No

14 220 kv BBMB Narela 1

48.8Hz, ∆t:0.15s

49.9Hz,0.2Hz/s,Inst. OK No No

15 220 kv Narnaul 1 No 49.28Hz,0.2Hz/s,Inst OK No No

16 220 kv Narwana 2 48.8Hz, ∆t:0.15s No OK No No

17 400 kv Panipat BBMB 1

48.8Hz, ∆t:0.16s

49.9Hz, 0.2Hz/s,Inst. OK No No

18 220 kv Pehowa 1 No 49.9Hz, 0.2Hz/s,Inst. OK No No

19 220 kv Rewari 1 48.8Hz, Inst. 49.9Hz, 0.3Hz/s, Inst. OK No No

20 220 KV Tepla 1 No No OK No No


At 7 stations the UFRs and df/dt relays operated with settings as per NRPC recommendations on both the grid incidents in July’2012. At 1 station (Nissing) the UFR operated only on 31st July’12 incident.

At balance 12 stations the UFRs & df/dt relays were installed but have not operated during each grid disturbance incidents of July’12 out of the total 20 stations and could not enable the target combined load relief of 1300MW from Haryana system.

F] Uttrakhand System:

The status of Uttrakhand system UFRs and df/dt operations during the July’12 grid disturbance incidents with NRPC recommended settings is as under: Sl NRPC recommended UFR & df/dt settings Expected load

relief (MW) Status of operation of UFRs and df/dt relays in Uttrakhand system as per NRPC recommendations.

1a UFR setting - 48.8Hz 30 At 1 station (Kashipur) UFR operated only on 31-07-12



2a df/dt Stg-1 freq 49.9 Hz Slope 0.1Hz/sec 70 Setting not implemented

2b df/dt Stg-2 freq 49.9 Hz Slope 0.2Hz/sec 70 At 2 station df/dt relay operated (Rishikesh & Chilla 50Hz set freq. sl 0.2s).

2c df/dt Stg-3 freq 49.9 Hz Slope 0.3Hz/sec 70 Setting not implemented

Total

UFRs- 110

df/dt- 210



Status of Uttrakhand Stations where UFRs & df/dt relays were declared installed to NRPC Sr. No.

Name of Substation







1 132 kv Jwalpur 1 48.6Hz ∆t-0.6s

No OK Yes Yes

2 132 kv Chilla 1 No 50Hz, 0.2 Hz/sec

OK Yes Yes

3 220 kv Rishikesh 1 No 49.9Hz, 0.2Hz/sec

OK Yes Yes

4 132 kv Kashipur 1 48.8Hz Inst No NA No Yes

5 132 kv Kulhal 0 No No NA No No

6 132 kv Mazra 1 48.2Hz Inst No Ok No No

7 132 kv Rorkee 1 48.6Hz, ∆t-0.15s

No Not Commissioned

No No

8 132 kv Dhakarni 0 No No NA No No

9 132 kv Haldwani 1 47.7Hz, Inst. No OK No No

10 220 kv Khodri 1 Relay installed on 27.08.12

No Relay installed on 27.08.12

NA NA

11 132 kv Bhowali 1-FCX Not Connected

NA NA NA NA

From the above it can be summarized as follows: At total 3 numbers of substations the UFR & df/dt relays operation took place on both grid incidents in July’12 as per NRPC relay settings. However at Kashipur UFR operation took place on 31-07-12 only. The target combined load relief of 320MW during each grid disturbance incidents could not be achieved.

G] Jammu & Kashmir System: The status of J&K system UFRs and df/dt operations during the July’12 grid disturbance incidents with NRPC recommended settings is as under: Sl NRPC recommended UFR &

df/dt settings Expected load relief (MW)

Status of operation of UFRs and df/dt relays in J&K system as per NRPC recommendations.

1a UFR setting - 48.8Hz 40 Setting not implemented









Total

UFRs- 165

Df/dt- 270



Status of J&K Stations where UFRs & df/dt relays were declared installed to NRPC is as under: Sr. No.

Name of Substation Nos of UF relays at Stn


Df/dt Setting Hz (Hz/sec), Inst./Time delay




1 220/132/33 kV L'dhampur

1 (MFVUM) 48.49Hz,Inst. No OK Yes Yes

2 132 kV Khillani(Doda) 1 (MFVUM) 47.96Hz,Inst. No OK No No

3 132/33 kV Akhnoor 1 (MFVUM) Not operational

No OK NA NA

4 132/66 kV Hiranagar 1 (MFVUM) Not operational

No NA NA NA

5 132/33 kV Jhajjarkotli 1 (MFVUM) Not operational

No NA NA NA

6 132/33 kV Miran Sahib

1 (MFVUM) Not operational

No OK NA NA

7 220/132/33 kV Udhampur

0 No No NA NA NA

From the above it can be summarized as follows

No UFRs were provided at 1 stations (Udhampur) also UFRs were not operational at another 5 stations (Hiranagar, Jhajjarkotli ,Akhnoor, Miran Sahib & Khillani(Doda)).

At 1 station of L’dhampur(48.49Hz different than the NRPC recommendation) the UFR was reported to have been operated during the grid disturbance incidents. In J&K system no UFRs & df/dt relay operated at recommended frequency settings out of the total 7 stations and could not enable the target combined load relief of 435MW during each grid disturbance incidents.

H] Himachal Pradesh System: The status of HP system UFRs and df/dt operations during the July’12 grid disturbance incidents

with NRPC recommended settings is as under: Sl NRPC recommended


Status of operation of UFRs and df/dt relays in HP system as per NRPC recommendations.

1a UFR setting - 48.8Hz 20 1b UFR setting - 48.6Hz 20

Operated at 1 station (Darlaghat-48.8 & 48.6Hz ∆t- 0.1s)

1c UFR setting - 48.2Hz 75 Not operated at 1 station 2a df/dt Stg-1 freq 49.9 Hz

Slope 0.1Hz/sec 50

Not operated at 1 station 2b df/dt Stg-2 freq 49.9 Hz

Slope 0.2Hz/sec 70 Setting not implemented



Total

UFRs- 115

df/dt- 190



Status of Himachal Pardesh Station where UFRs & df/dt relays were declared installed to NRPC is as under:

Sr. No.



Df/dt Setting Hz (Hz/ sec) ,Inst./Time delay




1 132 kv ACC Barmana 1 48.8, 48.6Hz, Inst.

No OK No No

2 132 kv Darlaghat 1 48.8, 48.6Hz, ∆t:0.1s

No OK Yes Yes

3 220 kv Kunihar 2 48.2Hz, Inst. 49.9Hz, 0.1Hz/s, Inst.

OK No No

From the above it can be summarized as follows

Only at 1 station (Darlaghat), UFR with time delay setting operated out of the total 3 stations. No UFR & df/dt relays operation took place in HP system at the NRPC recommended frequency settings. Accordingly the targeted combined load relief of 305MW during each grid disturbance incidents could not be achieved.

I] Chandigarh System: The status of Chandigarh system UFRs and df/dt operations during the July’12 grid disturbance incidents with NRPC recommended settings is as under: Sl NRPC recommended


Status of operation of UFRs and df/dt relays in CHD system as per NRPC recommendations.

1a UFR setting - 48.6Hz 10 Setting not implemented correctly. 2a df/dt Stg-2 freq 49.9 Hz

Slope 0.2Hz/sec 50


50

Setting not implemented

Total

UFRs- 10

df/dt- 100



Status of Chandigarh Stations where UFRs & df/dt relays were declared installed to NRPC is as under Sr. No.


FLAT UFR Setting (Hz), Inst. Or Time delay

Df/dt Setting Hz (Hz/sec), Inst./Time delay




1 66 kv Ind. Area Phase - I CHD

1 48.5,∆t: 10 sec No OK No No

2 66 kv Ind. Area Phase - II CHD

1 48.5,∆t: 8 sec No OK No No


The two stations (66kV Ind. Area Ph-I & Ph-II) relays were observed to be set at 48.5Hz each with time delays of 10 seconds and 8 seconds respectively and remained inoperative during grid incidents.

No UFR & df/dt relay operation took place in CHD system at recommended frequency settings out of the total 2 stations. Hence targeted relief of 110MW during each grid disturbance incidents could not be achieved.

J] Conclusion:

After the audit carried out for df/dt and under frequency relays at 175 substations of 9 constituents, the status of the relays are as follows:

State Peak load typical

Expected Flat UFR Load Relief

Total Expected Load Relief with df/dt relays

Expected combined Flat UFR and df/dt load relief

Installed as per NRPC/ Consituents (Total stations)

No of stations where UFRs & df/dt relays are not provided

No of stations where UFRs & df/dt relays not-operated as per NRPC recommendations

No of Stations with UFRs &df/dt relay operated as per NRPC recommendation

% of UFRs & df/dt relay operation as per NRPC recommendations

MW MW MW MW Nos Nos Nos Nos %

Punjab 6558 650 1410 2060 28 12 11 5 18%

Haryana 4201 400 900 1300 20 0 13 7 35%

Rajasthan 4946 495 1070 1565 50 9 26 15 30%

Delhi 3736 400 810 1210 24 0 17 7 29%

UP 7531 705 1060 1765 30 7 20 3 10%

Uttrakahand

991 110 210 320 11 4 4 3 27%

HP 873 115 190 305 3 0 3 0 0%

J & K 1309 165 270 435 7 4 3 0 0%

CHD 247 10 100 110 2 0 2 0 0%

Total 30392 3050 6020 9070 175 36 99 40 23%

It may be observed from above that out of total 175 stations of various constituents of NR, the UFRs and df/dt relays operated at 40 numbers of stations which were set as per the NRPC recommendations. Thus a total of only 23% of the total number of stations were reported to have provided relief during the grid incidents of July’2012.

� Against the total targeted load relief of 6020MW through df/dt relays, 14% was reported on 30th July’12 and the same was only 9% on 31-07-12. Where time delays have been provided in the df/dt relays the same may be reviewed for the instantaneous setting.

� The load relief under UFR was reported to be 25% on 30th July’12 incident and 24% on 31-07-12 against the total targeted relief of 3050MW.

� The combined UFR & df/dt load relief on 30th July’12 and 31st July’12 were 18% and

14% respectively against the target relief of 9070MW.

� It was also observed during the site visits that the testing of UFRs was initially done during commissioning only. Records of any periodic testing were not evident from the site feedback reports. From a number of places non-availability of the test kits was reported from the sites.

K ] Suggestions:

I. The UFR & df/dt relays which have not operated during the July2012 grid incidents,

are required to be tested to make them functional on emergent basis.

II. The balance under frequency and df/dt relays are to be installed and commissioned by the constituents at the designated sub-stations to provide the desired relief urgently as committed at NRPC meetings.

III. The installed relays are required to be relooked for fresh settings and re-commissioning with instantaneous tripping of df/dt as per the recommendation of NRPC without any time delay.

IV. Review of flat under frequency and df/dt settings considering present load scenario.

V. Review of load relief at each substation with feeders details for various voltage level.

VI. The under frequency and df/dt may be replaced with numerical type so that following features can be achieved: • Storage of past data • Remote status monitoring at ALDC/SLDC/RLDC • Remote programming • Remote on line real-time load flow of each feeders for load shedding • Time synchronisation from remote • Tripping from remote under special protection scheme • Easy for developing islanding scheme for the constituents by monitoring the relay

condition with trip circuit healthy and real time load flow on feeders

VII. Installation of OPGW / Fibre optic for direct speech (hot line) / data communication with ALDC/SLDC/RLDC.

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report on status of state wise ufr & df/dt ... 132kv hanuman garh 1 48.8hz, inst. no ok yes yes...

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