Current transformer secondary overvoltage protection
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Explanation
Currenttransformer (CT)in the power system, widelyused in time measurementand control, normalwork, the currenttransformer secondaryside is similar toshort-circuit condition, the output voltageis very low.In theoperation of the secondarywinding open circuit,orabnormal current flows throughthe primary winding,(thundering current,over-current resonantcapacitor charging current, the inductorcurrent starts, etc.),will beknownin thegeneration of secondaryor even thousands ofvoltsvoltsovervoltage.This is not onlyharmfulto the secondarysystem insulation, but also theradical and burning transformers, and even endangerthe lives and safetyof staff.UseZD-CTcurrent transformer secondaryover-voltageprotection device caneffectively preventopen current transformercaused the accident.
Main purpose
ZD-CTcurrent transformer secondaryover-voltageprotection is mainlyused for a varietyof CT secondaryside of the abnormalover-voltageprotection.Protective devices connected toboth ends ofthe secondary winding,small leakage duringnormal operation,ahigh-impedancestate.When an abnormalovervoltageprotection devices rapidlyaction and short circuitfault locationis displayed onthe panel,and a passivesignal output.When troubleshooting, circuit restitutionafter heagainput into normal operation.ZD-CTcurrent transformer secondaryover-voltageprotection CTsecondary side of thedifferential winding, over-currentwinding, measuringwindingbus protection, standby windingand so on.
Technical Specifications
1, the normalleakage current: <1Ma 2, theturn-on voltageUc: 150V ± 10% 3,on-timeTs: 500ms ≤ Ts ≤ 250ms 4,remote relay contactcapacity: AC220V/5A 5, the protection relaycontact capacity: AC220V/15A 6,using the CT size: the secondary peakis greater than 150V 7, the protection current: ≥ 5A 8, the working environment: Temperature:-200C ~ 700C Humidity: ≤ 95% RH 9,reset:press the "reset" button;automatically "reset" 10, the seismic performance: 10 ~ 50-10HZ 2g 3min 11, anti-interference: 4.4KV / M 12,Dimensions: CTB-1: 48 × 48 × 90 (mm) CTB-(2 ~ 6): 145 × 90 × 73 (mm) 13, voltage: 2KV 50HZ 1min 14, Installation: surface layout, rail orfixed installation
Main features
1, the normalworkhours, into theprotection of the currentdoes not exceed0.1Ma,CT does not affectnormal operation. 2, when theA (orB, C), Nvoltage is higher than150Vshorted CTBA (orB, C, N). 3, the relaycontact capacity greater than15A.Therefore, failure to makereliable short-circuitthe CT secondary side. 4, the relaycontacts with a holdfunction,press the "reset" buttonto remove protection. 5, if thepower to liftfailure, power downautomatically after the deviceis reset. 6, the deviceprovides a pair ofnormally open contacts anda pair of normallyclosed contacts.Can be accessed byall kindsof light alarmor provide comprehensiveprotectionso remote. When the protective action, normally open, normally closedto open.
Wiring diagram
Under normal circumstances, transformersare connected to theA, B, Cphase, the smallconnectionintwophases,an individualconnected toaphase.Mostarestar connected, a fewdelta connection.This productcurrent transformersecondary windingprotectionfor thestar connection.Secondary windingsA, B, Cconnected to the protectorcorresponding toA, B, Cterminals.A, B, Cthree-phasesecondarycenter(virtual groundN)connected to theprotection of the"N"terminals.If we confineA, Bwindings, C phasewiring can not,will not affect theprotection work. AC220V50Hzpower accessprotectionfor internalelectrical components,threepassive signalline leadsfor the user tousean external ACor DCcan be.For example, the commonand normally closedcablegreenlights,lights thatprotection work.Commonand normally opencable connection, "red" lightoralarm,the workthatprotectionhasdetected a secondarywindingopen circuit failure.
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