脉冲封锁保护方式在静止无功发生器中的应用

APPLICATION OF PULSE BLOCKING PROTECTION METHOD IN STATCOM

静止无功发生器（ＳＴＡＴＣＯＭ）装置设计中的一个关键问题是保护系统的设计。脉冲封锁保护方式可使装置在经受瞬时扰动或故障后迅速投入使用，不必经历缓慢的启动并网过程。文中以国内第１台±３００ｋｖａｒＳＴＡＴＣＯＭ工业样机为例，分析了变压器磁路不饱和与饱和两种情况下脉冲封锁引起直流侧过电压的机理。引入的抑制直流侧过电压的附加电路已成功运用于±３００ｋｖａｒＳＴＡＴＣＯＭ。现场测试结果表明了分析的正确性及抑制过电压的有效性。

The protection system plays a very important role in STATCOM equipment. The pulse blocking protection method can make STATCOM go into operation immediately after the instant when transient disturbance or system fault disappears. Based on the analysis of the first 300 kvar STATCOM prototype in China , this paper illustrates the principle of DC side over-voltage in two cases: linear transformer model, transformer model with saturation. The DC side high voltage will damage the capacitor and inverter. A novel assistant circuit to suppress the DC side over-voltage is introduced and it has been successfully employed in 300 kvar STATCOM prototype. This kind of pulse blocking method is not only suitable for STATCOM, but also for all other FACTS and power electronic devices based on self-commutated voltage source inverter.