基于Rogowski谐振原理及小波能谱的暂态保护

Transient Protection Based on Rogowski Coil Resonance Theory and Wavelet Energy Spectrum

提出一种基于Rogowski谐振原理和小波能谱的配电网单端暂态保护新方案,即在线路边界接入Rogowski谐振装置,以此改变线路边界谐振频率处暂态信号传输特性,从而区分区内外故障,以实现配电网的全线速动.通过小波变换模极大值确定故障发生时刻,然后提取故障时间段内谐振频段信号和低频段信号,并计算频段信号能量比值大小即可获得可靠的保护判据.最后通过PSCAD/EMTDC仿真验证该保护方案的有效性,并且该方案在不同的故障状况下均能可靠地区分区内外故障.

The paper presents a new single terminal transient protection scheme for distribution network based on Rogowski coil resonance theory and wavelet energy spectrum.The transmission characteristics of transient signal of the line boundary were changed by introducing Rogowski coil resonance equipment,and the internal fault was distinguished from the external fault.Consequently,an immediate trip was realized among the distribution network.After determining the fault moment by wavelet modulus maxima,the high and low frequency band signals in the fault period were extracted so that a reliable protection criterion was obtainted by calculating ratio of high-frequency energy and lower-frequency energy.Finally,PSCAD/EMTDC simulation results prove the effectiveness of the proposed protection scheme,which is reliable to discriminate internal and external faults under different conditions.