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 pulse signal generation, noise discrimination and observation. 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 converted into a pulse A of a prescribed amplitude by a binary-coding circuit 11a. After the AC voltage is stepped down, a time difference between the pulse and a processing system is corrected by a phase-shifting circuit 15a, and a signal generating circuit 16a gives a pulse every time when a phase angle of the voltage reaches a prescribed value, while a gate 17 selects these pulses and gives a pulse S1. Based on signals A-C and S1, a logic circuit 12 gives a pulse S2 of 'H' when the signals A-C are of partial discharge. Using the signals S2 and A-C, a logic circuit 13 judges the pulses to be of a partial discharge when the one-phase or two-phase outputs A-C and the signal S2 are 'H' and adds 1 to a count circuit 19. Noise can be removed accurately from the discharge pulse by using the characteristics of the phase angle and the partial discharge pulse according to this constitution, and therefore the partial discharge can be measured with high precision.