10kV配电网内部过电压研究

Research on Internal Over-Voltage of 10kV Power Distribution Network

针对某变电站10 k V配电网内部过电压频发现状,利用ATP-EMTP计算了投切电容器组、铁磁谐振的过电压水平,提出了相应抑制措施。研究表明:切除电容器组过电压水平高于投电容器组,其两相重燃过电压高达3.6 p.u.,建议加避雷器限制;对地电容较小时系统易发生基频谐振,大于0.2μF时发生分频谐振,采用励磁特性较好的PT能有效抑制铁磁谐振。

Aiming at the current situation that the over-voltage took place frequently in certain substation of 10kV power distribution network, this paper used software ATP-EMTP to calculate the over-voltage level of switching capacitor bank and ferroresonance, and proposed the corre-sponding braking measures. Research shows that when the over-voltage level of turn-off capacitor bank was higher than that of turn-on capacitor bank, its two-phase reburning over-voltage was up to 3.6p.u., so as to adopt arrester limitation; when the earth capacitance was small, the funda-mental resonance took place in the system easily and if the capacitance was more than 0.2μF, the fractional frequency resonance took place, so as to adopt the voltage transformer with better excitation characteristics to suppress ferroresonance effectively.