500 kV GIS变电站隔离开关操作对二次电缆的影响

Influence of 500 kV GIS Substation Disconnect Switch Operation on Secondary Cables

特快速暂态过电压(very fast transient over-voltage,VFTO)经电容式电压互感器(capacitive voltage transformer,CVT)传播,会在其二次侧形成很大的干扰,影响二次设备的正常操作和运行。该论文建立了CVT等值计算电路模型,对二次电缆上的骚扰电压进行了推导计算,基于电磁暂态仿真软件建立了某500 kV GIS变电站VFTO对二次电缆骚扰的整体仿真模型,对二次电缆末端的骚扰电压进行了仿真分析,研究了二次电缆长度、屏蔽层接地方式对于骚扰的影响,并提出了采用螺旋管阻尼母线、屏蔽层两端接地、采通多股导线、加装滤波电容的组合抗干扰措施,大大降低了二次电缆骚扰电压的幅值和谐波成份。

When the very fast transient overvoltage(VFTO)propagates through capacitive voltage transformers(CVT),it can create significant interference on their secondary sides,and affect the normal operation and functioning of secondary equipment.In this paper,the CVT equivalent calculation circuit model is established,and the disturbance voltage of the secondary cable is deduced and calculated.Based on the electromagnetic transient simulation software,the overall simulation model of the secondary cable disturbance caused by the VFTO in a 500 kV GIS substation is established,the interference voltage at the end of the secondary cable is simulated and analyzed,and the effects of the length of the secondary cable and the grounding mode of the shield on the disturbance are studied.It also puts forward the combined anti-interference measures of using spiral tube damping busbar,grounding at both ends of the shield,using multi-strand conductors and installing filter capacitors,which greatly reduce the amplitude and harmonic components of the disturbance voltage of the secondary cable.