换流器同步机模拟控制中的小干扰稳定策略

基于同步电机模拟控制的电压源换流器可以对电力系统稳定发挥积极作用。为此,提出了一种适用于同步电机模拟控制的小干扰稳定辅助控制策略,该策略通过在电压源换流器的同步电机模拟控制中加入一个简单的一阶环节,即小干扰稳定模块来实现。推导了加入小干扰稳定模块后的电压源换流器的动态方程,并通过小信号分析揭示了该模块阻尼振荡的作用机理,指出了其可以在整个系统稳定运行区间内增大阻尼的特性。在PSCAD/EMTDC软件环境中建立了基于本文控制策略的单站无穷大系统和三机九节点系统,并进行了详细电磁暂态仿真。仿真结果表明配置小干扰稳定模块后的电压源换流器,不但可以增大单站无穷大系统的阻尼,而且能够与传统同步发电机协同配合,阻尼多机电力系统的振荡。

Small-signal Stability Enhancement Scheme for the Synchronous Generator Emulation Control of Voltage Source Converter

The voltage source converter with the synchronous generator emulation control(SGEC) strategy is expected to play a positive role in power system stability. We put forwad a small-signal stability enhancement scheme for the SGEC strategy of the voltage source converter, which is realized by adding a simple first-order unit to the SGEC strategy. The dynamic equation of SGEC strategy with the proposed small-signal stability enhancement scheme is derived. In the corresponding small-signal equation, the power system damping is found to be increased with the stability enhancement scheme. A single-converter infinite-bus system as well as a 3-machine 9-bus system with the proposed control scheme are established in PSCAD/EMTDC software environment, and detailed electromagnetic transient simulations are performed. The simulation results show that the oscillations in the two studied systems are both damped with the small-signal stability enhancement scheme, and the voltage source converter coordinates well with the conventional synchronous generators.