1、IEEE C37.234 Guide for Protective Relay Application to Power System Buses B.Kasztenny (Chairman), S.Conrad (Vice-Chairman), P.Beaumont, K.Behrendt, O.Bolado, J.Boyle, G.Brunello, J.Burger, F.Calero, S.Chano, G.Dalke, A.Darlington, H.DoCarmo, D.Fontana, Z.Gajic, J.Holbach, L.Kojovic, F.Lopez, D.Lukac
2、h, D.McGinn, J.Miller, P.Mysore, J.OBrien, B.Pickett, S.Sambasivan, G.Sessler, V.Skendzic, J.Smith, D.Tholomier, M.Thompson, J.Uchiyama, D.Ware, D.Weers, R.Whittaker, R.Young, S.ZochollPresentation to the Main Committee of PSRC, January 14, 2010, Orlando, FL迈鼎 http:/Table of Contents Definitions Bus
3、 configurations Introduction to bus protection Relay input sources Bus protection methods Application of bus protection schemes AnnexesDefinitions 23 new terms defined Bus protection and primary equipmentbreaker substitution Temporary usage of a bus tie breaker in a multiple bus configuration to sub
4、stitute for one of the network elements circuit breakers, typically for the maintenance of the latter; also known as breaker transfercheck zone Nonselective part of a multi-zone bus protection system measuring current flows around the entire station and supervising selective tripping from individual
5、 bus zones of protectionstub bus Area of a bus or line that becomes isolated from the original zone of protection or an area that loses protection due to the loss of sensing to zone protection relaysBus design considerations Continuity of service for the bus and essential network elements Equipment
6、maintainability and network switching flexibility Economical and footprint constraints Sectionalizing requirements to avoid exceeding breaker fault duties Ease of future bus expansionBus arrangements Single bus Main and transfer bus Double-bus double-breaker Double-bus single-breaker Breaker-and-a-h
7、alf Ring busMain and transfer busMain and transfer busIntroduction to bus protection Zones of protection Bus protection methods Scheme selection guidelinesZones of protectionDynamic zones of protectionDynamic zones of protectionDynamic zones of protection Zones of protectionBus protection methods Di
8、fferential Differentially-connected overcurrent Instantaneous Time-delayed Percentage-restrained differential Restrained Advanced microprocessor based High-impedance differential Resistor-stabilized overcurrent High-impedance Partial differential overcurrent Fault busBus protection methods Zone-inte
9、rlocked schemes Simple blocking Directional blocking Time-coordinated relays overlapping the bus Protection (sensors) built into the gas isolated switchgear* Not covered in the GuideScheme selection criteria Bus arrangement and flexibility Fixed vs. switchable buses Availability and characteristics
10、of CTs For reconfigurable buses, availability of auxiliary contacts of disconnect switches Performance requirements Security, Selectivity, Speed, Sensitivity Cost and complexityScheme selection Relay input sources Current transformers Types Accuracy classes Equivalent circuit & time to saturation No
11、 universal CT requirements Voltage Transformers Voltage trip supervision Directional blocking schemes Position of switches and breakersDetailed scheme review Section 7 gives in-depth review of each method following a consistent patternTheory of operationSetting considerationsCT requirementsApplicati
12、on considerationsExample High-impedance schemeVoltage setting:Above the maximum voltage for an external fault assuming that one CT saturates completely High enough so that pickup current is above the short circuit current on the secondary of any PT or station service transformer inside the bus zoneB
13、elow the accuracy class voltage rating of the lowest accuracy class CT in the differential circuit Low enough so that pickup current is below the minimum fault current for the busExample High-impedance schemeCT requirements:CTs dedicated to bus protection (cannot be shared)Equal CT ratios*The accura
14、cy class voltage rating of the CT with the lowest accuracy class above the selected voltage setting, with margin* Ratio matching covered but discouragedApplication of bus protection Partial differential Loads Capacitor banks Application with overcurrent and distance relays Combined bus and transform
15、er zone Buses with directly connected grounding transformers Application of auxiliary transformers Generally discouragedApplication of bus protection Applications with paralleled CTs Generally discouraged Guidelines includedApplication of bus protection Application of auxiliary tripping relays Locko
16、ut relays Non-lockout relays Ratings Automatic reclosing after bus faults Dynamic bus replica Check-zone Voltage trip supervisionDynamic bus replicaPosition of switches and breakers“If not opened, then closed” logicIn-service transferIn-service transferIn-service transferCheck zoneCheck zoneApplicat
17、ion of bus protection Application of CT trouble detection Detection methods Fallback strategies Reliable, selective tripping at the differential zone boundary Line-side CT Bus-side CT Bus coupler considerations The role of Breaker Failure protectionLine-side CTBus coupler considerationsBus coupler c
18、onsiderationsApplication of bus protection CT column ground fault protection In-zone grounds Surge arresters Safety grounds and circulating current while testing In-zone grounding of out-of-service elements In-service transfer of network elements and breaker substitutionBreaker substitutionApplicati
19、on of bus protection Stub bus considerations Breaker Failure considerations Backup protectionLocal backup Duplicated relays BF, batteries, wiring Reverse-looking distance relays Overcurrent relaysRemote backupAnnexes Setting example for a high-impedance scheme (Annex A) Logic example for double-bus
20、single-breaker configuration (Annex B) Bus and Breaker Failure protection Two zones, check zone and voltage supervision In-service transfers and breaker substitution Setting guidelines for differentially connected OC schemes (Annex C)C37.234 Highlights Complex bus arrangements and switching Advanced bus protection topics (reconfigurable buses, mP relays) Balanced coverage of high- and low-impedance schemes Protection scheme selection guidelines CT requirements given per scheme List of application considerations Detailed examples for most common schemes
