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4. CAPACITIVE VOLTAGETRANSFORMERS ANDCOUPLING CAPACITORSOil-paper insulation› 420 kV Capacitivevoltage transformers.Fingrid, Visulahti(Finland).34Instrument transformers High voltage
4. CAPACITIVE VOLTAGE TRANSFORMERS AND COUPLING CAPACITORS Oil-paper insulationINTRODUCTIONCapacitive voltage transformers isolate themeasuring instruments, meters, relays, protections, etc., from the high voltage power circuitand provide a scaled replica of the voltage inthe HV line.They enable transmission of high frequencysignals through the high voltage (HV) lines.Coupling capacitors are only used for couplinghigh frequency communication signals, makingthem equivalent to the capacitive part of a CVT.Capacitive voltagetransformer:model DFK up to 800 kV,model DDB up to 170 kV.Coupling capacitor:model DFN up to 800 kV,model DDN up to 170 kV.› Model DFK› Model DDNInstrument transformers High voltage› Model DDB35
4. CAPACITIVE VOLTAGE TRANSFORMERS AND COUPLING CAPACITORS Oil-paper insulationSECTIONS1.2.3.4.5.6.Primary terminalOil volume compensating systemInsulator (porcelain or silicone rubber)CapacitorsIntermediate voltage tapHigh frequency terminal7. Inductive voltage transformer8. Oil level indicator9. Carrier accessories10. Oil sampling valve11. Grounding terminal12. Secondary terminal box123467589121011› Capacitive voltage transformer36› Coupling capacitorInstrument transformers High voltage
4. CAPACITIVE VOLTAGE TRANSFORMERS AND COUPLING CAPACITORS Oil-paper insulationAPPLICATIONSIdeal for installation at metering points dueto its very high accuracy class and extremelysteady capacitance.2. Protection for high voltage lines andsubstations.Transmission of high-frequency signals throughthe high voltage lines (PLC).Helps to reduce voltage peaks in the line.Examples of applications:1. Revenue metering.3. Transmission of high frequency signals.M› 400 kV Capacitivevoltage transformers.R.E.E. (Spain).Instrument transformers High voltage37
4. CAPACITIVE VOLTAGE TRANSFORMERS AND COUPLING CAPACITORS Oil-paper insulationDESIGN AND MANUFACTURECapacitive voltage transformers consist of aseries of capacitors connected in series ontop of a tank in which the electromagneticunit (inductive transformer (5), series reactor(8) and auxiliary elements) is housed. Thesecapacitors form a voltage divider (2, 3)between the high voltage terminal (1) and thehigh frequency terminal (4).12345The capacitors, impregnated with high gradedielectric oil, are housed in one or moreinsulators. Each of them forms an hermeticallysealed independent unit, with a very stablecapacitance over time.678The high frequency terminal (4) for the PLCsignal comes out of one side through a pieceof resin that separates the capacitive unit fromthe inductive voltage transformer.The medium voltage inductive voltagetransformer is immersed in mineral oil andhoused inside an hermetically sealed metallictank.The secondary terminals are located insidethe secondary terminal box (7) enablingconnection; sufficient space is available toinstall protection elements such as fuses orcircuit breakers.1.2.3.4.5.6.7.8.6Primary terminalCapacitorsCapacitorsHigh frequency terminalInductive voltage transformerFerroresonance suppression circuitSecondary terminal boxCompensating reactor› Grounding switch forsafety handling duringoperation.› Protection devices forthe secondaries maybe installed inside theterminal block.38Instrument transformers High voltage
4. CAPACITIVE VOLTAGE TRANSFORMERS AND COUPLING CAPACITORS Oil-paper ›››High stability of capacity, and therefore ofaccuracy.Reliable ferroresonance suppression system that does not affect transient responseor accuracy.Excellent mechanical resistance to seismicforces.Pressure relief device to guarantee maximum safety.Robust mechanical strength and reducedsize due to a compact design that is easyto transport, store and install, and whichreduces visual impact.Hermetically sealed to guarantee completewater tightness with the minimum volume ofoil or gas (Each unit is tested individually).OPTIONS:››››Silicone rubber insulation.››Sealable secondary terminals.›››Carrier accessories.Ground switch for the inductive part.Wide range of primary and secondaryterminals.Line traps can be mounted on top of theCVT.Different cable glands and accessoriesavailable.Wide range of capacitances.Secondary terminal protectioninside the terminal box.devicesOil level compensating system that effectively regulates changes in oil volume.Maintenance-free throughout their lifespan.Environmental-friendly design through theuse of materials that are recyclable andresistant to the elements. Its advanced design adheres to environmental regulationsthrough the use of high quality insulatingoils, free of PCB.Excellent response under extreme weatherconditions (from -55 C; up to 55 C),altitudes over 1,000 m.a.s.l., seismic hazardareas, violent winds, etc.Maximum safety andreliability within acustom-mmade design.Each transformer is routine tested for partialdischarges, tangent delta (DDF), insulationand accuracy and designed to withstand allthe type tests included in the standards.Compliance to any international standards:IEC, IEEE, UNE, BS, VDE, SS, CAN/CSA, AS,NBR, JIS, GOST, NF Officially homologated in-house testingfacilities.Instrument transformers High voltage39
4. CAPACITIVE VOLTAGE TRANSFORMERS AND COUPLING CAPACITORS Oil-paper insulationRANGEARTECHE capacitive voltage transformersand coupling capacitors are named withdifferent letters (DDB or DFK for transformers;DDN or DFN for capacitors) followed by 2 or3 numbers indicating the maximum voltage ofthe network for which they are designed.The tables show the ranges of both types ofdevices currently built by ARTECHE. Thesecharacteristics are merely indicative; they canbe manufactured to comply with any domesticor international standard.Standard accuracy classes and powers:››HHAccording to IEC standards100 VA Class 0,2 / 3P250 VA Class 0,5 / 3PAccording to IEEE standards0.3 WXYZ1.2 WXYZ, ZZHigher accuracy classes and burdens available.AAAA› Coupling capacitor› Capacitive voltage transformer› 245 kV Capacitivevoltage transformers.NEPCO (Jordan).› 525 kV Capacitivevoltage transformers.UTE (Uruguay).40Instrument transformers High voltage
4. CAPACITIVE VOLTAGE TRANSFORMERS AND COUPLING CAPACITORS Oil-paper insulationCapacitive voltage transformersRated insulation 5001530045070101270DFK-420420DFK-525(525) 550DFK-765(765) roximate dimensions and weights. For special requirements, please consult. Higher capacities available upon request.Coupling capacitorsRated insulation 5035007700105004504335495DFN-525(525) 55030006200131254505300890DFN-765(765) 801950142597521001550Approximate dimensions and weights. For special requirements, please consult. Higher capacities available upon request.Instrument transformers High voltage41
Capacitive voltage transformer: model DFK up to 800 kV, model DDB up to 170 kV. Coupling capacitor: model DFN up to 800 kV, model DDN up to 170 kV. 4. CAPACITIVE VOLTAGE TRANSFORMERS AND COUPLING CAPACITORS Oil-paper insulation › Model DDN › Model DDB They enable transmission of high frequency signals through the high voltage (HV) lines.
