NERC Requirements for Setting Load-Dependent Power Plant Protection: PRC-025-1

Transcription

1 NERC Requirements for Setting Load-Dependent Power Plant Protection: PRC Chuck Mozina, Consultant Beckwith Electric Company

2 NERC Reliability Standards Transmission System Generator Coordination - PRC STATUS OF STANDARD: + Approved by NERC Aug Approved by FERC July Effective Date For Compliance Starts Oct. 1, Time to Implement Months PURPOSE: To Set Load-Responsive Generator Protective Relays at Level such that Generators do not Trip During System Disturbances, Avoiding Damage to Generator. APPLICABILITY: Generator Owners, Transmission Owners, Distribution Providers APPLIES TO: + Generating Unit(s) + Generator Step-Up Transformer. + Auxiliary Transformers that Supply Auxiliary Power When Generator is On-Line + Backup Transmission Line Protection for Lines Exiting Power Plants

3 NERC PRC-023 Transmission System Loadability J X Z3 Zrelay 30 = 0.85 x VL-L 3 3 Max. Torque Angle 30 0 R

4 NERC Generator Setting Guide Western Protective Relay Conference 2014

5 Basic Generator Excitation System NERC Simulation Increased Load at Generator Transmission Bus to Pull Down Voltage to 0.85 PU

6 PRC Load-Dependent Generator Relays

7 PHASE DISTANCE IMPEDANCE BACKUP (21)

8 System Phase Fault Backup (21) For a fault at F, the approximate apparent impedance effect is:

9 Transformation from MW-MVAR to R-X Plot MVA = kv 2 Z ( R c ) R v MW MVAR R-X PLOT

10 Phase Backup (21) Setting Criteria: Options PRC-025-1

11 Phase Backup (21) Setting Criteria: Option #1 PRC-025-1

12 Phase Backup (21) Setting Criteria: Option #2 PRC-025-1

13 Phase Backup (21) Setting Criteria: Option #3 PRC-025-1

14 IEEE PHASE BACKUP (21) SETTING COORDINATION 30.0 jx LONGEST LINE (WITH IN FEED), 75.5 OHMS GCC GCC ZONE2 Can t Provide Remote BU due to Loadability Constraints SH OR T E ST LI N E (NO INFEED) ZONE 2 50% to 67% OF RPFA MTA ZONE1 SYSTEM May have to Upgrade Transmission System Protection Delineated Pri & BU and Local BF. RPFA ZONE TRANSFORMER HIGH SIDE R -5.0

15 NERC vs. IEEE PHASE BACKUP (21) SETTING COORDINATION Proposed NERC Test Points NERC Test Point Converted to an Impedance at Close to.95 pu voltage (Option 1)

16 IS LOAD ENCROACHMENT A GOOD IDEA? SUGGESTED BY PRC NERC Test Points NERC Test 1.0pu Mw + j [1.5 Mw pu] Mvars

17 Voltage Control/Restraint Overcurrent (51V)

18 Voltage Control/Restraint Overcurrent (51V) Not as Good as 21 Method of Providing Phase Fault Transmission System Backup Difficult to Coordinate with Transmission Line Impedance Relays Originally Designed for Industrial System Backup Protection

19 VOLTAGE RESTRAINT (51VR) CHARACTERISTIC Voltage Restraint Characteristic Tap Setting as % of Tap Setting at Rated Voltage Input Voltage (% of rated voltage)

20 PHASE BACKUP (51VR) SETTING CRITERIA: OPTIONS PRC-025-1

21 PHASE BACKUP (51VR) SETTING CRITERIA: OPTION #1 PRC-025-1

22 PHASE BACKUP (51VR) SETTING CRITERIA: OPTION #2 PRC-025-1

23 PHASE BACKUP (51VR) SETTING CRITERIA: OPTION #3 PRC-025-1

24 PHASE BACKUP (51VC) SETTING CRITERIA: OPTIONS PRC-025-1

25 GENERATOR STEP-UP TRANSFORMERS (GSU) & AUXILIARY TRANSFORMERS

26 GSU 51T APPLICATION Western Protective Relay Conference 2014

27 GSU (51T) SETTING CRITERIA: OPTIONS GSU PRC Western Protective Relay Conference 2014

28 GENERATOR STEP-UP 51T TRANSFORMERS OPTION #1 PRC-025-1

29 GENERATOR STEP-UP 51T TRANSFORMERS OPTION #2 PRC-025-1

30 AUXILARY TRANSFORMERS COVERED BY PRC-025-1

31 AUXILARY TRANSFORMERS (51) SETTING CRITERIA: OPTION PRC-025-1

32 POWER PLANT TRANSMISSION LINE BACKUP PROTECTION

33 Transmission Line Backup Relays (21)

34 Transmission Line Backup Relays (21)

35 TRANSMISSION LINE BACKUP (21) SETTING CRITERIA: OPTION #1 PRC-025-1

36 TRANSMISSION LINE BACKUP (21) SETTING CRITERIA: OPTION #2 PRC-025-1

37 Conclusions As a Result of NERC Analysis of 2003 Blackout Data, NERC Developed Voltage Ride-Through Criteria for Power Plants. The Voltage Ride-Through Setting Options are Outlined in NERC Standard for Load Responsive Relays (PRC-025-1). Adopted by FERC on July 2014 with Order Effective as of Order Oct.1, The Standard will Result in Very Limited Remote Backup by Generator 21 and 51V relays. This May Require Upgrade of Transmission Line Protection for Lines Exiting Power Plants.

38 NERC Requirements for Setting Load-Dependent Power Plant Protection: PRC Questions?