The voltage level higher and higher, current transformer secondary winding current accuracy, the correct action related to the protection and testing, measurement accuracy

With the development of network, more and more high voltage level, current transformer secondary winding current accuracy, the correct action related to the protection and testing, measurement accuracy. Early vote in the substation when tested on the current transformer is to ensure correct operation of relay protection and  Circuit breaker , measurement accuracy of the necessary conditions. Currently, we use more feedthrough current air circuit breaker  windings are measured difference method and the method of ampere-turns, etc., because these two methods can not simulate actual field, often overlooked in the calibration of the external magnetic field, resulting in on-site verification when the measurement error increases. Found the problem in the Substation, we check for current  power transformers , the use of other current comparative law, that the last increase 200A current, secondary display 0.2A, test connection. The results showed that the seven 330kV current transformer windings error tolerance. Experimental data show that the phase current transformer current measured value is found from the above data, all winding current into and out of imbalance, and laboratory equipment from the current transformers were tested farther, the smaller the error, the greater the contrary.