变电站空投主变压器对电容器组的影响仿真研究

Simulation Study of the Influence on Capacitor Banks when Switching on a No-load Main Transformer in Substation

采用PSCAD/EMTDC电磁暂态仿真软件,对变电站空投主变压器时相邻主变压器电容器组所受的影响进行了仿真研究。首先,从原理上分析由空投主变压器引起的和应涌流现象,以及由此对电容器组谐波分布的影响;其次,通过建模仿真,得出空投主变压器时相邻运行变压器电容器组的波形及谐波分量,并进一步分析影响电容器组谐波水平的可能因素。仿真结果表明,变电站空投主变压器时,可能使相邻并联运行变压器电容器组支路的谐波分量出现大幅度增加,从而引起电容器组过电流;除系统内部因素如变压器饱和特性、系统等值电阻等之外,变压器合闸时刻、合闸时的系统运行方式以及电容器组的投切情况等外部因素都会影响电容器组的谐波放大水平。

With electromagnetic transient simulation software PSCAD/EMTDC, the influence on the main transformer capacitor banks when an adjacent no-load main transformer is switched on is simulated and researched. First, the resultant phenomenon of sympathetic inrush current and its influence on the harmonic distribution of capacitor banks are analyzed theoretically. Then the waveforms and harmonic components of the adjacent transformer capacitor banks in operation when a no-load main transformer is switched on are achieved by modeling simulation. Finally, the possible factors that will affect the harmonic level of capacitor banks are analyzed. The result shows that in substations, it is possible the harmonic components of the transformer capacitor banks will increase greatly when an adjacent no-load main transformer is switched on, which will result in overcurrent of the capacitor banks. Moreover, besides the system internal factors such as transformer saturation characteristics and system equivalent resistance, the external factors such as the switching-in time of transformer, the system operation mode when switching, and the switching of capacitor banks will also affect the harmonic component level of the capacitor banks.