基于人工过零技术的直流真空分断过程分析及验证

Analysis and test for the DC Vacuum interruption process based on the artificial current zero technology

针对人工过零直流真空分断过程,分析研究了影响真空分断特性的主要因素,并通过试验样机对直流真空分断过程进行了验证。研究结果表明,通过提高直流短路故障识别及快速真空开关分断速度降低弧后触头间隙的初始金属蒸汽浓度,在快速真空开关支路串联饱和电抗器减小电流过零后的电流变化率,为快速真空开关并联阻容缓冲电路减缓弧后暂态恢复电压的上升过程,设计快速真空开关动触头的最佳位移曲线并确定最佳燃弧区间避免换流分断过程中产生阳极斑点,从而改善大电流真空电弧后介质恢复特性,提升分断性能。研究成果为开发工程实用的直流真空断路器奠定了实践基础。

Aiming at the process of DC vacuum interruption with artificial current zero,some main factors influencing on the vacuum breaking characteristic were analyzed and studied.And the DC vacuum interruption process was verified by the prototype test.The research results indicate that the post arc dielectric recovery characteristic for a high current vacuum arc is improved,prompting a more reliable interruption process through some improvements as followed.The post arc initial metal vapor density was reduced by speeding up the DC fault detection and the fast vacuum switch(FVS)breaking.A much lower current rate of fall after zero is realized with a saturable reactor connected with the FVS in series.Adding a resistor&capacitor snubber parallel connected with the FVS makes the post arc transient recovery voltage rise more slowly.And the vacuum arc anode spot is avoided though a optimum design of FVS breaking movement characteristic and arcing interval.The achievement is worthy for development of a practical DC VCB.