METHOD FOR TESTING LIGHTNING IMPULSE VOLTAGE OR TRANSFORMER

摘要

PURPOSE:To obtain a method for testing which discriminates the dielectric breakdown of a winding by comparison of voltage and current waveforms with good accuracy by carrying out a test while changing non-linear resistors in such a manner that the performance characteristic of the non-linear resistors when a full wave declining voltage is impressed thereto and the performance characteristic when a full wave test voltage is impressed thereto are made the same. CONSTITUTION:Both terminals of the low voltage winding 12 are grounded. One end of the high voltage winding 13 is connected to a voltage impressing terminal 21 and the other end to a tap winding 14. The 2nd non-linear resistor 16 is short circuited by a short circuit device 18 and only the 1st non-linear resistor 15 is shunted and connected to the tap winding 14 to apply the full wave declining voltage thereto. The voltage and current waveforms are then observed on an oscilloscope, etc. by a voltage divider and resistor 22 connected to the terminal 21. The device 18 is opened to impress the full wave test voltage to the resistor and the waveforms are observed. The limiting voltage is so selected that the currents flowing in the non-linear resistors are made approximately equal in each test. The voltage waveform generated at the winding 14 is compared with an approximately resembling waveform and a fault is discriminated from the presence or absence of the waveform distortion.