组合波作用下负载性质对电涌保护器配合影响研究

Study of Influence of Load Properties on SPD Coordination under Combination Wave

负载性质对于组合波冲击下的浪涌保护存在一定影响,研究负载性质对电涌保护器(SPD)配合的影响具有重要意义。利用PSCAD软件搭建组合波发生电路,采用IEEE推荐的氧化锌压敏电阻等效模型,分析阻性、容性、感性负载幅值对负载端过电压的影响,讨论负载性质对前后级SPD电流分流比与吸收能量的影响。仿真结果表明:阻性负载和容性负载对负载端过电压数值影响不大,感性负载对负载端过电压数值影响较大;电容幅值越小,负载端过电压波形振荡越明显。前后级SPD分流比随着负载幅值的增加而降低;分流比受连接电缆长度影响较大,前后级SPD连接电缆越长,分流比越高。随着负载幅值的增大,前后级SPD能量吸收比均有所增加。阻性负载和容性负载下SPD配合效果较感性负载好。

Load properties have some influence on characteristics of voltage and current surges under combination wave, so it is necessary to study on the effect of load properties on surge protection device （SPD） coordination. The combination wave generator （CWG） is established in PSCAD as well as the IEEE ZnO varistor model. The characteristics of voltage and current surges with different types of loads are analyzed. Current split ratio and absorbed energy ratio of pre and post stage SPDs are also discussed. The simulation results show that： resistive load and capacitive load have a little effect on overvohage across equipment under test （EUT）, which is opposite to inductive load; waveform of the overvohage shows more significant oscillation with the increasing of capacitive load. Current split ratio of pre and post stage SPDs all decreases with the rise of load amplitudes which is in contrast with length of cable line. Absorbed energy ratio of pre and post stage SPDs all increases with the rise of load amplitudes. Appropriate coordination effect is particularly obvious under resistive and capacitive loads.