交流系统强振荡期间直流输电控制保护响应仿真

目前，针对交直流混联大电网中交流系统失步振荡期间，直流输电控制保护响应特性的研究鲜见。文中通过PSCAD仿真和实时数字仿真（RTDS），分析了交直流混联大电网系统中交流电网强振荡时直流输电控制保护系统的响应特性。仿真中，交流电网包括真实电网和虚构电网，直流输电系统包括单一直流和多馈入直流。仿真结果表明，直流输电系统在振荡前2个周期内不会闭锁，稳定控制系统有充足的处理时间。直流控制保护系统的非线性特性造成2个极闭锁时间存在差异，有利于避免双回、双极同时闭锁。振荡期间直流控制保护系统的调节和换相失败造成直流输送功率大幅度波动。

Simulation on Response of HVDC Transmission Control and Protection During Strong Oscillation in AC System

At present, there are few researches on the response characteristics of control and protection system for DC transmission during the out-of-step oscillation of AC systems in large-scale AC/DC hybrid power grid. This paper analyzes the response characteristics of the control and protection system for DC transmission with a strong oscillation in AC grid of the large-scale AC/DC hybrid power grid based on PSCAD simulation and real-time digital simulation (RTDS). In the simulation, a real AC grid, a fictitious AC grid, and single- and multi-infeed DC transmission systems are set up. The simulation results show that the DC transmission system will not be blocked in the first 2 cycles of oscillation so that the stability control system has sufficient processing time. There is a difference in the blocking time of the two poles caused by the non-linear characteristics of the DC control and protection system, which helps to avoid the simultaneous blocking of double circuits and two poles. During oscillation, the adjustment of the DC control and protection system and commutation failure will cause the DC transmission power to fluctuate greatly.