網(wǎng)絡(luò)互動營銷幾個關(guān)鍵點(diǎn)

1、網(wǎng)絡(luò)互動營銷幾個關(guān)鍵點(diǎn)Table of ContentsDefinitionsBus configurationsIntroduction to bus protectionRelay input sourcesBus protection methodsApplication of bus protection schemesAnnexesDefinitions23 new terms definedBus protection and primary equipmentbreaker substitution Temporary usage of a bus tie breaker in

2、a multiple bus configuration to substitute 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

3、 selective tripping from individual 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 considerationsContinuity of service for the bus and ess

4、ential network elementsEquipment maintainability and network switching flexibilityEconomical and footprint constraintsSectionalizing requirements to avoid exceeding breaker fault dutiesEase of future bus expansionBus arrangementsSingle busMain and transfer busDouble-bus double-breakerDouble-bus sing

5、le-breakerBreaker-and-a-halfRing busMain and transfer busMain and transfer busIntroduction to bus protectionZones of protectionBus protection methodsScheme selection guidelinesZones of protectionDynamic zones of protectionDynamic zones of protectionDynamic zones of protection Zones of protectionBus

6、protection methodsDifferentialDifferentially-connected overcurrentInstantaneousTime-delayedPercentage-restrained differentialRestrainedAdvanced microprocessor basedHigh-impedance differentialResistor-stabilized overcurrentHigh-impedancePartial differential overcurrentFault busBus protection methodsZ

7、one-interlocked schemesSimple blockingDirectional blockingTime-coordinated relays overlapping the busProtection (sensors) built into the gas isolated switchgear* Not covered in the GuideScheme selection criteriaBus arrangement and flexibilityFixed vs. switchable busesAvailability and characteristics

8、 of CTsFor reconfigurable buses, availability of auxiliary contacts of disconnect switchesPerformance requirementsSecurity, Selectivity, Speed, SensitivityCost and complexityScheme selection Relay input sourcesCurrent transformersTypesAccuracy classesEquivalent circuit & time to saturationNo univers

9、al CT requirementsVoltage TransformersVoltage trip supervisionDirectional blocking schemesPosition of switches and breakersDetailed scheme reviewSection 7 gives in-depth review of each method following a consistent patternTheory of operationSetting considerationsCT requirementsApplication considerat

10、ionsExample 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 zoneBelow the accu

11、racy 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 accuracy class volt

12、age rating of the CT with the lowest accuracy class above the selected voltage setting, with margin* Ratio matching covered but discouragedApplication of bus protectionPartial differentialLoadsCapacitor banksApplication with overcurrent and distance relaysCombined bus and transformer zoneBuses with

13、directly connected grounding transformersApplication of auxiliary transformersGenerally discouragedApplication of bus protectionApplications with paralleled CTsGenerally discouragedGuidelines includedApplication of bus protectionApplication of auxiliary tripping relaysLockout relaysNon-lockout relay

14、sRatings Automatic reclosing after bus faultsDynamic bus replicaCheck-zoneVoltage trip supervisionDynamic bus replicaPosition of switches and breakers“If not opened, then closed logicIn-service transferIn-service transferIn-service transferCheck zoneCheck zoneApplication of bus protectionApplication

15、 of CT trouble detectionDetection methodsFallback strategiesReliable, selective tripping at the differential zone boundaryLine-side CTBus-side CTBus coupler considerationsThe role of Breaker Failure protectionLine-side CTBus coupler considerationsBus coupler considerationsApplication of bus protecti

16、onCT column ground fault protectionIn-zone groundsSurge arrestersSafety grounds and circulating current while testingIn-zone grounding of out-of-service elementsIn-service transfer of network elements and breaker substitutionBreaker substitutionApplication of bus protectionStub bus considerationsBreaker Failure considerationsBackup protectionLocal backupDuplicated relaysBF, batteries, wiringReverse-looking distance relaysOvercurrent relaysRemote backupAnnexesSetting example for a high-impedance scheme (Anne