适用于逆变型电源接入的故障方向判别新方法

Novel method of fault direction identification for inverter-interfaced power supply access

由于新能源电源馈出的短路故障特性与同步发电机存在较大差异,当传统方向元件应用于新能源场站的联络线和集电线时,无法保证其动作的正确性。因此根据逆变型电源馈出的短路电流的特点,提出一种适用于逆变型电源接入的故障方向判别新方法。该方法利用序电压进行故障类型判断,在此基础上,根据正、反方向故障时各序电流比值和电流幅值差异,进行故障方向辨识。数字仿真结果表明,该方法在不同故障类型下均能正确判断故障方向,且受过渡电阻的影响较小,具有良好的工程应用价值。

The characteristics of short circuit current of renewable energy sources are quite different from those of traditional generators.When applied to tie lines and collector lines of renewable energy stations,the traditional direction components may not operate correctly.A novel method of fault direction identification suitable for the inverter-interfaced power supply access based on the fault features of renewable energy sources is proposed.The fault type is judged by sequence voltage,and the fault direction is identified according to the difference of sequence current ratio and current amplitude between forward and backward faults.The digital simulative results show that the proposed method can correctly judge the fault direction in different fault types,and is less affected by the transition resistance,so it has good engineering application value.