The SF6 insulated standard capacitor can be used together with a C and tan delta measuring bridge as a comparison standard for exact measurements of the capacitance and tan delta of HV equipment such as cables, transformers, bushings, capacitors, etc. The standard capacitors of the series NK or 3370 can also be used as an AC divider for the exact measurements of AC voltages in the industrial frequency range (with add. internal electrode or add. secondary part).
The capacitor is provided with a top electrode which allows partial discharge free interconnections to the other elements of the HV circuit. The capacitor is built as steel pressure vessel, with bushing for voltages up to 30 kV included. Above this voltage the measuring capacitance Cs is formed by the metallic pressure tank and the corresponding internal concentric electrode. The electrodes are insulated from each other with SF6 gas. All capacitors are fitted with a pressure indicator and filling valve. Surge arrestors protect the measuring output from transients.
Datasheet:
3370 Standard Gas Capacitor Features
Highly stable capacitance with no influence from atmospheric pressure and humidity
Very low internal dissipation factor (tan delta) and PD free
Use for exact measurements of capacitance and tan delta together with a tan delta measuring bridge
Use as an AC divider for exact measurements of AC voltages
Simultaneous tan delta and voltage measurement possible upon request
Linear field distribution at very high voltages
Higher voltage withstand capability even at humidity levels up to 95 % without condensation
High temperature and voltage coefficient stability is granted