十脉冲下限压型SPD级间串联退耦电感前后能级匹配研究

退耦电感是限压型浪涌保护器(SPD)级联配合核心元件, 对于限压型SPD能级匹配具有重要影响。针对退耦电感与限压型SPD能级匹配问题, 基于行波传输理论建立多级限压型SPD能量匹配模型, 并结合更接近自然雷击的10个8/20μs多脉冲试验进行研究, 试验结果可知: 恒定波阻抗下, 增大SPD线路间退耦电感值, 可有效减缓雷电瞬态过电压上升速率。SPD并联时, 氧化锌压敏电阻压敏电压对前后级分流比影响较小, 与残压值呈正相关关系。SPD级联电感值越大, 前级SPD泄流越多, 后级SPD箝压水平越高, 能级匹配效果越好。当出现磁饱和时, 前级SPD泄流显著降低, 后级SPD的泄流显著增加, 为避免出现该现象, 实际装设SPD时, 级间选装的退耦电感值在合理范围内应稍大于理论电感值。 

ARESEARCH ON ENERGY LEVEL MATCHING OF SERIES DECOUPLING INDUCTANCE BETWEEN STAGES OF TEN-PULSE LOWER-LIMITING SURGE PROTECTOR

Decoupling inductors are the core components of voltage-limiting surge protector(SPD) cascade coordination and they have an important impact on the energy level matching of voltage-limiting SPD. The present study focuses on the coupling between decoupling inductors and voltage-limiting SPDs. In the present research, a multi-level voltage-limiting SPD energy matching model is established based on the traveling wave transmission theory, and it is combined with 10 8/20μs multi-pulse tests that are closer to natural lightning strikes. The test results show that under constant wave impedance, increasing the decoupling inductance value between SPD lines can effectively slow down the rate of lightning transient overvoltage rise. When SPDs are connected in parallel, the zinc oxide varistor voltage has little effect on the shunt ratio of the front and rear stages and is positively correlated with the residual voltage value. The larger the SPD cascade inductance value, the more the pre-SPD leakage, the higher the post-SPD clamping level, and the better the energy level matching effect. When magnetic saturation occurs, the leakage current of the front-stage SPD is significantly reduced, and the leakage current of the subsequent-stage SPD is significantly increased. To avoid this phenomenon, when SPD is installed, the decoupling inductance value between the stages should be within a reasonable range and slightly larger than the theoretical inductance value.