工频试验变压器快速保护装置中限流电抗器的参数选择

Optimization of Current Limiting Chokes in Quick Protection Device of Test Transformer

工频试验时，试品放电后产生的恢复过电压最大值可达试验电压幅值的２ 倍．快速保护装置通过将试验变压器原边经限流电抗器快速短路的方法可有效抑制此类过电压．其中限流电抗器的参数决定了装置动作时短路电流的大小和过电压倍数．提出了优化选择该参数时应遵循的原则，建立了仿真计算的数值模型，给出了一种收敛速度较快的逐次估算逼近方法，并用电磁暂态程序对一套实际工频试验系统进行了仿真计算，结果完全达到了预期目标．

High recovery voltages in the case of a disruptive discharge on the test object is liable to increase up to twice the rated value of the test voltage. Normal methods can't prevent this quickly ascending overvoltages. The new quick protection device can guarantee an effective protection against the recovery voltages after discharge by shortcircuiting the primary terminals of testing transformer via current limiting chokes in a very short time. This paper gave a rule for parameter setting of current limiting chokes which determine the value of short circuit current and the overvoltage multiple, established numerical models for optimization calculation using EMTP (electro magnetic transient program), and gave a successive parameter estimation method to obtain high convergence rate. The optimization calculation results and relative waveforms of an actual testing system were presented.