配电网超低频振荡的仿真计算研究

STUDY AND SIMULATION CALCULATION OF VERY LOW FREQUENCIES OSCILLATIONS IN POWER DISTRIBUTION SYSTEM

通过数学分析得出系统等值对地电容较大时 ,接地故障消失激发的超低频振荡会产生危及系统安全的过电流 ;EMTP仿真计算表明超低频振荡最大过电压 <2 .0p .u .,而其过电流最大倍数却可高达 5 2 8p .u .;通过分析提出了TV高压侧中性点串联电阻、系统装设消弧线圈等 。

Single-phase earth faults and arcing ground faults appeare frequently in the distribution system of neutral point isolated. If the ground capacitance is correspondingly large, faults disappeare will excite very low frequencies oscillations. It is found in this paper, oscillation over current may be endangering stability and safety of electric equipments. A systemic simulation using Electro-magnetic Transient Program (EMTP) about these oscillations is presented, the result is that the highest voltage in very low frequencies oscillations is less than 2.0p.u but the highest current is 528p.u. The paper also presents some method to eliminate over current which restrain those over current effectively, such as primary neutral point of TVs grounded by resistor or using arc suppression coil.