抄録
This paper presents a new scheme of protection and fault location in multi-terminal high voltage lines. The new protection scheme is PCM (Pulse Code Modulation) current differential protection using OPGW (Optical Fiber Ground Wire). This scheme can be applied to protection upto 8-terminal transmission lines. This scheme has coped with the miss trip in the cause of CT-saturation. But this way have an opposite result what obstruction of trip during 4-cycle. Then, we propose the index for use of cope with the miss trip for CT-saturation.
And above system get various information at each terminal (e.g. current data and CB-condition et al). Then, we have devloped fault location scheme using this information. It has two kinds of technique using the synchronized current data of multi-terminal lines. One technique is to measure current diversion ratio with current of each terminal. The other technique is to measure impedance using current of each terminal and voltage. This scheme can automatically choose between the two technique at fault type. The equipment using this scheme has obtained a good result in field.
