MEASURING APPARATUS OF PARTIAL DISCHARGE

• Main Authors: TSUNODA YOSHIO, SAKAMOTO ATARU, NAKAGAWA MASAYOSHI
• Format: Patent
• Language: English
• Published: 01.09.1989
• Subjects: MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; TESTING

PURPOSE:To remove noise from a discharge pulse accurately and to conduct highly- precise measurement of partial discharge, by providing means of discharge pulse detection, gate signal generation and arithmetic processing. CONSTITUTION:A three-phase AC voltage being applied to cables, a pulse is discriminated from the voltage of a cable Ca by a transformer PTa, and it is amplified and then subjected to polarity discrimination. Negative and positive pulses are inputted separately to binary-coding circuits 12a and 13a and converted into pulses of prescribed amplitudes respectively. Meanwhile, an AC component is stepped down, a time difference between the pulse and a processing system is corrected in a phase-shifting circuit 17, and a pulse S1 is delivered from a gate signal generating circuit 18 every time when the phase angle of the impressed AC voltage reaches a prescribed value. Using signals A<->-C<-> and A<+>-C<+>, discrimination circuits 14 and 15 conduct logical operations and deliver outputs S2 and S3. Subsequently, an AND gate 19 receives these outputs S1-S3 as inputs and delivers same to a count circuit 20. Since noise can be removed from a partial discharge pulse accurately by using the characteristics of the AC voltage, the polarity of the discharge pulse, etc. according to this constitution, highly precise measurement of partial discharge can be conducted.