550kV GIS站VFTO计算及抑制方法研究

Study on VFTO Calculation and Inhibition Method of 550kV GIS Station

VFTO对设备的危害随着额定电压的提高而增大,超特高压VFTO的抑制对保障GIS变电站设备安全运行起到重要作用。文中提出一种阻尼母线的设计思想,该阻尼母线由镂空螺线管及与之并联的电阻组成,在工频下,对母线的绝缘性能、通流能力及力学性能不造成影响,在高频下,行波电流在电感端形成高电压,其两端阻尼电阻可在高压作用下吸收行波能量。文中建立某550kV典型GIS站VFTO计算模型,分别对该550kV GIS变电站检修转运行8种情况的40种操作方式下变电站各主要节点VFTO情况进行分析,得到隔离开关操作产生最大VFTO的分布图。依据最大VFTO幅值分布情况加装阻尼母线,经计算,由隔离开关操作产生的高幅值VFTO次数显著减少,整站VFTO最大幅值由3.0 p.u.降低至2.2 p.u.而将母线Ⅰ右端出现的3.0 p.u.的幅值降低至了1.4 p.u.。研究结果表明:阻尼母线可有效降低VFTO幅值及频率,对降低由于VFTO造成的GIS内部设备、外部连接设备以及二次设备的安全问题有显著效果。

The damage of VFTO to the equipment increases suppression of VFTO is of great importance to guarantee the safe with the increase of the rated voltage, and the operation of the equipment of the GIS substation. Bus design thought, this paper puts forward a kind of damping of the damper bus consists of hollow out solenoid and parallel with the resistance, under power frequency, the insulation performance of busbar, flow capacity and mechanical properties of impact, under the high frequency, the traveling wave current form high voltage through the inductor, the wave energy can be absorbed by the two end damping resistors under the high voltage. This paper set up a typical 550 kV GIS station VFTO calculation model, the analysis of the VFTO situation of the main nodes of the substation are analyzed under the cases of the 550 kV GIS substation maintenance turns 40 kinds of operating mode under the eight kinds of running condition, the distribution diagram of the maximum VFTO generated by disconnector operation is obtained. According to the largest VFTO amplitude distribution of busbar equipped with damping, by the calculation, high amplitude VFTO produced by isolating switch operation times is significantly reduced, site VFTO most large amplitude reduced from 3.0 p.u. to 2.2 p.u., and bus bar I right end of 3.0 p.u. amplitude reduced to 1.4 p.u.. In this paper, the research results show that the damping bus can effectively reduce the VFTO amplitude and frequency, to reduce caused by VFTO GIS internal equipment, external connection equipment and secondary equipment safety issues have a significant effect.