高压直流换流阀阻尼电容全工况试验方法研究

Research on Testing Method in Full Working Condition of Damping Capacity in HVDC Valve

阻尼电容是直流换流阀的重要组成部件,起着抑制晶闸管关断过电压和提供晶闸管控制单元能量等作用,其运行可靠性决定着换流阀的安全稳定运行,需要对其全工况下运行性能进行考核,而电压、电流及其变化率峰值的复现是关键。为此,提出了一种基于全桥子模块级联的电路拓扑及其控制方法,实现了输出电压波形可实时控制,仿真验证了整流、逆变和90°暂态运行工况下阻尼电容电气应力。基于所提出的电路拓扑,研制了波形可编程控制电压源,试验复现了整流、逆变和90°暂态运行工况下阻尼电容电气应力。提出的试验方法和研制的试验平台能验证直流换流阀阻尼电容全工况下的长期运行可靠性,为换流阀安全稳定运行提供了支撑,同时还可验证其它应用场景下的电容全工况下的长期运行可靠性。

Damping capacitor is an important component of DC valve,which can restrain over-voltage when thyristor turns off and provides energy for thyristor control unit,and its operational reliability determines the safe and stable opera-tion of the converter valve.Therefore,its long-term operational performance in full working condition needs to be examined,and the peak reproduction of voltage,current and changing rate is the key problem.In this paper,a circuit to-pology and its controlling method based on full-bridge sub-modules in series are presented,and the output voltage waveform can be controlled in real time.The electrical stresses of damping capacitor under rectifying mode,inverting mode and 90°transient operating mode are verified by simulations.Based on the proposed circuit topology,a voltage source whose waveform is controlled programmablly is developed.The electrical stresses of the damping capacitor are reproduced in the tests under the modes of rectifying,inverting and 90°transient operating modes.The proposed test method and the developed test platform can be adopted to verify the long-term operation reliability in full working condi-tion of the damping capacitance of thyristor valve,and provide supports for the safe and stable operation of the converter valve.At the same time,the method can also be adopted to verify the long-term operational reliability in full working condition of capacitors in other applied scenarios.