NK SERIES, 3370 Standard Capacitors The SF6 insulated standard capacitor is used together with a C and tan delta measuring bridge (e.g. 2840). As a comparison standard for exact measurements of the capacitance and tan of HV equipment like cables, transformers, bushings, capacitors, etc. The capacitor is provided with a top electrode which allows partial discharge free interconnections to the other elements of the HV circuit. The SF6 insulated standard capacitor is designed for indoor service and is mobile designed. The standard capacitors of the series NK or 3370 are used for: SPECIAL FEATURES For very high voltages a grad with discrete capacitor elements achieves a linear field distribution. These results in higher voltage withstand capability even at humidity levels up to 95 % without condensation. High temperature and voltage coefficient stability is granted. Exact measurements of the capacitance and tan delta Exact measurements of AC voltages (AC divider) in the industrial frequency range (with add. internal electrode or add. secondary part). 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.

TECHNICAL DATA OF NK SERIES Type NK Base frame dimension B (*1): for 3370 NK/1000/30 (1000pF, 30kV) the capacitance specification is 5 % (*2): only up to 2500 V (for NK 5 only)big b

TYPICAL ELECTRICAL STANDARD CAPACITOR MEASUREING CAPACITANCE AND TAN The standard capacitors are used in conjunction with bridges for measuring capacitance and tan due to their very stable capacitance and very low inherent losses. Capacitance and tan bridge type 2840 MEASURING GENERAL TECHNICAL DATA Stability of the capacitance Loss of pressure tan Insulation resistance Voltage drift (0 ... Un) Frequency drift (10 ... 1000 Hz) Operating temperature Storage temperature The standard capacitors are used in Transformer Measuring Systems (like TMS 580) due to their very high accuracy as voltage dividers....

BASIC SCOPE OF SUPPLY SPECIAL VERSIONS 1 standard capacitor with top electrode 1 mobile base frame 2 spare surge arrestors 1 instruction manual 1 test report Additional capacitance C13 for voltage measurement CALIBRATION Our basic standard for calibrating each standard capacitor is a PTB (Germany) calibrated internal standard. A standard capacitor should be re-calibrated every year. Haefely Test AG can provide these services, in our Basel works or on-site. ROUTINE TESTS IN THE FACTORY Normally, the capacitance, tan , and partial discharge values are tested before and after the 1,1 Un overvoltage...