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SF6 reference Capacitor - 400kV 50pF compressed gas standard capacitor

Genneal Information:

Compressed air standard capacitor is a necessary instrument in every HV test lab. It is used to

measure the capacitance of capacitor, cable, sleeve, insulator, transformer winding, and insulating

material, as well as tanδ of dielectric loss. At the same time, it can also be used as HV capacitor for

pressure sharing device of HV measuring capacitor. Under certain condition, it can be used as HV

coupling capacitor during partial discharge measurement.

Product Description


Standard capacitor is used as comparison reference, which is assorted to precise measurement to

inductance value, loss, capacitance, and dielectric loss value of HV equipment such as reactor,

cable, transformer, sleeve, and capacitors etc. The standard capacitor is equipped with HV pole

which can be connected with other HV parts in HV measuring circuit without partial discharge.

Standard capacitor is designed for indoor application, movable.

For extra high voltage, discrete capacitor grading is used to realize linear distribution of electric field,

so as to maintain an ambient humidity above 95% (without condensate water). Standard capacitor

has high voltage endurance and extremely stable humidity and voltage factor.


Specification :

  • 50 pF capacity, 400 kV nominal tension, SF6 insulated, electrodes to avoid corona that meets the following specifications.

  • Tangent delta: <10-5

  • Changes in capacity between 0% and 100% voltage: <5*10-5

  • Stability in time: 0.01% / year.

  • Temperature variation: 3 X 10 -5 K-1

  • Pressure variation: <1% / year

  • Frequency variation between 50 Hz and 1 kHz: <10-5

  • Partial discharge <5 pC



- Accuracy of the calibration at its rated operating range: Primary voltage: from 0% to 100% Vn.

- Testing frequency supported at industrial power frequency.



Ø Insulation sleeve and steel sheet made bottom and cover for casing. Bottom and cover are

fastened on both sides of insulation sleeve with stainless bolts and rings;

Ø Shielding case of capacitor is made of stainless pipe;

Ø HV/LV poles of capacitor is coaxial pole;

Ø Capacitor is equipped with pressure gauge and vent valve.

Ø Capacitor is filled with SF6. Pressure is 450±50kPa at 20 ℃.

Ø Capacitor frame is installed with universal wheel.

Ø External shielding plug socket of capacitor is adaptable to all kinds of bridge plugs



Application conditions:

  • RH: <80%

  • Ambient T: -5~+40℃

  • Altitude: <1000 m

  • Rated voltage 400kV

  • Withstand voltage: 440kV

  • Rated frequency: 50Hz

  • Capacitance: 50pF

  • Capacitance stability: 0.01%/%/year

  • Capacitance value accuracy: <5*10-5

  • SF6 working pressure: 450±50KPa

  • Capacitor tanδ: <1X10-5

  • Capacitance pressure factor absolute value: ≤2.2×10-3/0.1Mpa

  • Capacitance voltage factor absolute value: ≤3×10-5

  • Capacitance temperature factor absolute value: ≤3×10-5/℃

  • Capacitor shall bear 2Xrated air pressure test/72h.

  • Sealing: ≤1% leakage rate/y

  • Electric safety protection: LV pole overpotential protection

  • Gas standard capacitor installation dimension:

  • Base plate: 1650mm*1650

  • Height: 3600mm

  • Weight: <980kg


Complete supply:

  • Standard capacitor: 1set

  • Exclusive grading ring: 1piece

  • Exclusive measuring cable: 1piece

  • Junction box: 1piece

  • Factory inspection report: 1copy

  • Certificate: 1copy

  • Technical manual: 2copies

  • 0.05% measurement bridge 1 set

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