STUDY FOR THE INTRODUCTION OF DIGITAL COMMUNICATION USING OPTICAL FIBRE CABLES BETWEEN CONTROL ROOMS AND SWITCHYARD

Many copper cables for supervision, trip, measurements and control commands are laid between the switchyard equipment and the control room in the conventional substation. Therefore, it is difficult to remove the existing cables when the equipment is renewed, and to arrange the cable pits when the equipment is newly installed. In addition, since a large number of cables are connected, there is a problem that the construction period becomes longer. Therefore, to update the equipment easily, we studied the system configuration and information exchange method by digital communication technology reducing the number of cables between the switchyard equipment and the control room. We developed a prototype system, and field tests were conducted for the practical application of inter-equipment optical digital communication in a substation of the East Japan Railway Company. In the field test, we evaluated the prototype system compared to the conventional system not only by the performance test such as operation and transmission, but also by noise resistance performance test, workability check, and weather resistance check. We applied optical fibre cables to connect among the developed protection relay unit and field unit, instead of copper cables. In the substation, we evaluated abnormalities in power supply voltage, transmission line, CPU, etc. in outdoor environment. Also, we confirmed that trip signals and VT information are properly acquired by simulating relay operation, and we evaluated the redundancy in system configuration and protection performance. In conclusion, by using optical fibre cables for control cables except power supplies such as equipment and lighting, we confirmed that it is possible to significantly reduce the number of cables, and that work would become more efficient. We also confirmed that there were no problems about noise resistance, redundancy, and weather resistance.