Communication Aided Tripping. Common Methods, Schemes and Considerations

Transcription

1 Communication Aided Tripping Common Methods, Schemes and Considerations Presented by: Matt Horvath, P.E. March 13, 2017

2 Content Summary Background Purpose Methods and Mediums Schemes Considerations Application: 69 kv to 500 kv AC Transmission Lines 2

3 Content Traditional titlestep Distance Protection Content Developed area in 1910 s Instantaneous First Level Zone 1 coverage» ~ Second 60% of Level line Remaining ~ 40% of line cleared in Zone 2 time Zone 2 Relay 1 X X Remote Bus Zone 1 Relay 1 Remote Bus 3 3

4 Content Faster Fault title Clearing Required Content I 2 t damage area too high System First Level stability jeopardized Line is too electrically short to allow zone 1 reach setting Sequential tripping cases 4 4

5 Content Sequential titletripping Content May not area be possible for one terminal to detect faults: Fault Types Fault location Third Level Week source terminal Three terminal lines Strong Infeed Generally not acceptable 5 5

6 Content Goals For title Comm-Aided Tripping Content If Both area Terminals Can Communicate: 1. First Speed Level 2. Coverage 3. Primary 4. Simultaneous 5. Any Fault Type 6 6

7 COMM Aided Tripping Schemes Current Based (Communications Centered) Directional Comparison (Communications Assisted/Aided) 7

8 Content Direct Underreaching title Transfer Trip Content area Basic Logic for DUTT Scheme 8 8

9 Content DUTT Scheme title Continued Content area Advantages High speed operation for any line fault location Will» Second not over-trip Level for remote line faults Disadvantages Will not operate for faults beyond the underreach zone if Remote terminal is open Communications channel is inoperative DUTT signal is converted to trip without any local supervision 9 9

10 Content Permissive titleunderreaching Transfer Trip Content area Basic Logic for PUTT Scheme 10 10

11 Content PUTT Scheme title Continued Content area Advantages Same as DUTT, but added security provided by overreaching ements at receiving terminal Disadvantages Will not operate for faults beyond the underreach zone if Remote terminal is open Communications channel is inoperative Requires under and overreaching elements 11 11

12 Content Zone Acceleration title Content area Basic Logic for Zone Acceleration (Extension) Scheme 12 12

13 Content Zone Acceleration title Scheme Continued Content area Advantages Same as DUTT but with increased security for faults beyond» Second the Level standard underreach elements Disadvantages Will not operate for faults beyond the underreach zone if Remote terminal is open Communications channel is inoperative 13 13

14 Content Permissive titleoverreaching Transfer Trip Content area Basic Logic for POTT Scheme 14 14

15 Content POTT Scheme title Continued Content area Advantages Security Inherently well supervised, requires» Second Local fault Level detection by overreaching zone Permissive signal received from remote end Disadvantages Dependability Will not operate for internal faults when: Remote terminal is open Communication channel is inoperative 15 15

16 Content Directional titlecomparison Blocking Content area Basic Logic of DCB Scheme 16 16

17 Content DCB Scheme title Continued Content area Advantages Dependability Will continue to operate regardless of: Open terminal Communication channel failure Disadvantages Security Over-tripping concern No supervision during COMM channel failure Slight time delay 17 17

18 Content Directional titlecomparison Unblocking Content area 18 18

19 Content DCUB Scheme title Continued Content area Advantages Essentially same security as the POTT scheme May have dependability similar to that of the DCB scheme Disadvantages Requires additional & continuous Guard signal 19 19

20 Important Considerations Current Reversal Breaker Open Keying Echo Key Logic Week Infeed 20

21 Content Current Reversal title Content area Initial faulted state on parallel line: Zone 2A Key 21 21

22 Content Current Reversal title Continued Content area First breaker on faulted line opens: Zone 2B Key 22 22

23 Content Preventing titlecurrent Reversal Missoperation Content area Reverse Blocking zone Dropout Timer Criteria Third for Level dropout timer Maintains a block for Zone 2 permissive tripping until it expires Breaker C Opening Time + Zone 2 Reset Time + Channel Reset Delay Effective for both POTT and DCUB schemes Typical dropout timer delay ~ 4 8 cycles 23 23

24 Content Open Breaker title Conditions Content Problem area Key Solutions Continuous open-breaker keying Permissive-trip echo-keying Logic 24 24

25 Content Week Infeed title Logic Content area Zone 2A Strong Source Terminal Key A Zone 2B Weak Source Terminal Results: Terminal A: Trips by Time-Delayed Backup Terminal B: Possible Sequential Trip Solution in Relay B: Key B Supervise with Phase-to-Phase and/or Zero Sequence Overvoltage Element Trip Logic: Supervision AND Permissive Key 25 25

26 Content Echo Keying title Content Problems area Open Terminal» Weak Second Infeed Level Echo Supervision Duration Time Delay Pickup Time Delay Block Time Delay Strong Source Terminal Zone 2A Key A Zone 2B Weak Source Terminal Echo Key B 26 26

27 Communication Methods and Mediums On-OFF Frequency Shift Pulse-Code Phase-shift Keying Various Digital Telecommunications Operating Speed & Security 27

28 Content Pilot Wires title(copper) Content Developed area in 1930 s Telephone First Level Wire Twisted Pair 50Hz, 60Hz or DC 28 28

29 Content Audio Frequency title Tones Content Leased area or utility owned telecom lines Common frequency range:» Second 1 khz Level to 3 khz Line route flexibility Channel availability 29 29

30 Content Power-Line titlecarrier Content Developed area in 1930 s Superimposed First Level on transmission lines Line tuner & Coupling capacitor Line/Wave Traps Off/On or Frequency Shift 30 30

31 Content Microwave title Content area Developed in 1940 s First 1 GHz Level to 300 GHz» Point to Point Second Level 31 31

32 Content Digital Channels title Content Dedicated area Fiber Multiplexed First Level Fiber Systems SONET, T1 Digital Microwave, Radio link, or Telecom Line 32 32

33 Conclusion Comm-Aided Tripping Achieves: 1. Speed 2. Coverage 3. Primary 4. Simultaneous 5. Any Fault Type 33

34 References Industry Standards IEEE C Guide for Protective Relay Applications to Transmission Lines IEEE C Guide for Power System Protective Relay Applications of Audio Tones Over Voice Grade Channels Other Useful References Blackburn, Lewis J. and Domin, Thomas J. Protective Relaying Principles and Applications Reference Text, Third Edition, 2007 Schweitzer, Edmund O. and Kumm, John J. Statistical Comparison and Evaluation of Pilot Protection Schemes, Whitepaper, 23 rd WPRC

35 Questions? Thank You 35