| 摘要 |
Power system overvoltage protection is primarily accomplished by the application of Metal Oxide Varistors (MOVs). MOV voltage limiting capability may be enhanced by the application of power electronics. For instance, capacitor voltage suppression may be accomplished using a DVS system during switching to reduce inrush transient overvoltages or to remove trapped charges. This is achieved by dynamically changing the arrester characteristics. The DVS approach involves integrating an MOV block with anti-parallel thyristor pairs. A single DVS unit may be used to reduce inrush transient overvoltages when energizing. When de-energizing, the trapped charge is suppressed by sequentially bypassing several units. EMTP-based simulations demonstrate the overvoltage reduction may be reasonably accomplished. Potential benefits include improvement in power quality, life extension of equipment by reducing reactive switching overvoltages, use of conventional switchgear and a relatively fast switching response for reactive power control.
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