输电线路谐波过电压保护实现方法

在弱联系电网中，一台普通主变压器空载合闸后，随着其引发的励磁涌流注入到电网中，极有可能在系统末端产生较大的谐波畸变导致系统末端出现严重的谐波过电压，造成设备与负荷的损毁，带来严重的经济损失。为解决现有输电线路过电压保护无法反应谐波过电压的问题，提出了输电线路谐波过电压保护实现方法。该方法可正确反应输电线路中的基波过电压和谐波过电压，有效隔离谐波过电压在电网中的传播，保护设备免受谐波过电压的伤害。并通过试验验证了所提方法的有效性。

Implementation Method of Harmonic Overvoltage Protection for Transmission Line

In weak link power grids, after a normal main transformer closing without load,the inrush current is injected into power grid. It is very likely to cause large harmonic distortion at the end of the system, thus lead to serious harmonic overvoltage, which can cause damage to electrical equipment and load and bring serious economic losses. In order to solve the problem of over voltage protection which is unable to respond to harmonic overvoltage for the existing transmission lines, the method of harmonic overvoltage protection for transmission lines is put forward. The proposed method can correctly respond to fundamental overvoltage and harmonic overvoltage of transmission line, effectively isolate the propagation of harmonic overvoltage in power grid and protect equipment from harmonic overvoltage damage. The effectiveness of the proposed method is verified by experiments.