光耦器件瞬态饱和对微机保护装置的影响及对策

提出在快速瞬变扰动的作用下，光耦器件将产生瞬时饱和现象。指出瞬变扰动从直流电源、交流电流、电压端口施加时，即使开关量输入没有任何信号，光耦器件的输出也一直存在电平跌落、再恢复的过程，该过程伴随着每一个瞬变脉冲，相当于光耦器件已经导通，影响开关量输入的正确性。光耦器件用于串行口、开关量输出等回路时也存在上述现象。因此认为光耦器件瞬时饱和现象是普遍存在的，对微机保护装置影响较大，同时提出基于硬件、软件的解决方案。

RESEARCH ON TRANSIENT SATURATION OF OPTO-COUPLERS FOR ELECTRICAL FAST TRANSIENT/BURST

This paper presents a particular problem with opto-couplers that the short transient pulse can couple into the base of the receiving phototransistor and cause its saturation, which is named as transient saturation. It is found that when the electrical fast transient/bursts (EFTs) are "poured" into the ports of the DC power AC voltage and AC current circuits, although there is no useful signal, the level of output of opto-coupler falls off and comes back with every waveform of repetitive EFTs. This effectively "blinds" the opto-coupler. This saturation will affect opto-couplers' isolation and digital inputs' validity. The paper concludes that the "transient saturation" phenomenon can happen when opto-couplers are used in serial communication port and binary output port. The hardware and software solutions to opto-couplers' saturation are also suggested.