35kV母线CVT高压侧熔断器异常爆裂原因及解决方案研究

Research on the reason of the 35 kV bus CVT high-voltage side fuse abnormal bursting and the solution scheme

为了解决甘肃天水电网35kV侧母线CVT在电力电容器合闸时,其高压侧熔断器发生异常爆裂的事故,通过对电力电容器合闸过电压的Matlab仿真分析,得到了引起该事故的原因。电力电容器合闸过程产生的过电压激发CVT中间变压器铁芯饱和,进而引发CVT内部非线性电感和电容铁磁谐振,产生谐振过电流,使熔断器发生爆裂。针对这一原因,文中从限制电力电容器合闸过电压和对CVT消谐两个方面提出了解决方案。仿真验证这些方案具有可行性。

The fuse fixed on the high-voltage side of CVT that measures the 35kV bus voltage burst when closing the capacitors in Tianshui power network. Through using Matlab simulation to analyze the over-voltage when closing capacitors, the reason for this accident is gained .The over-voltage which is produced by closing capacitors inspires the transformer core saturation that triggers the nonlinear inductances and capacitances in CVT ferro resonance. Then over-current is produced that leads to burst in the fuse. For this reason, this paper brings forward the solutions from restricting the over-voltage in closing capacitors and eliminating resonance for CVT. Simulation verifies that these schemes are feasible.