新型双馈入直流输电系统无功调节特性分析

Analysis on Reactive Power Regulation in New Type Double-infeed HVDC System

针对多馈入直流输电（MIDC）系统的稳定性问题，将电压源型高压直流输电（VSC-HVDC）引入MIDC系统组成一种新型双馈入直流输电（DIDC）系统。在基于dq同步旋转坐标下，提出VSC-HVDC的基于有功、无功独立解耦控制策略，实现了DIDC的协调控制。充分利用VSC-HVDC对无功快速调节的能力，将其与常规无功补偿装置进行配合运行，提高系统稳定运行的能力。在PSCAD／EMTDC仿真环境下实验结果表明，在系统发生扰动的情况下，DIDC系统能够更有效地维持逆变侧母线电压的稳定，防止无功补偿装置振荡性投切，减少HVDC换相失败的概率，提高HVDC^4系统运行的可靠性。

To solve the stability problem of multi-infeed direct current （MIDC） transmission system, a new type double-infeed direct current （DIDC）system is introduced, which consists of a high voltage direct current （HVDC） subsystem and a voltage source converter-based HVDC （VSC-HVDC） subsystem. Based on dq synchronous rotating coordinate, an independent decoupling control strategy for active power and reactive power in VSC-HVDC system is proposed. And the coordinated control of DIDC is implemented. With capability of fast reactive power regulation in the VSC-HVDC system, stable operation of DIDC system can be achieved by coordinating conventional reactive power compensation devices into VSC-HVDC system. Experiments on PSCAD/EMTDC simulation platform show that, under disturbance circumstance, the DIDC system control can not only effectively maintain the stability of bus voltage at inverter side, but also prevent reactive power compensation devices from frequent switching and reduce the commutation failure risk, which is in favor of improvement of operation reliability of the system.