No. 1331
Survey results for the current specification and operation of protection relays in Japan and trends in overseas technology
Investigating R&D Committee on "Survey results for the current specification and operation of protection relays in Japan, and trends in overseas technology"
Keyword : protection relay, specification
Protection relays operate to secure the integrity of the power system by the tripping of the appropriate circuit breakers when abnormal power system conditions or power equipment failures occur. The influence of power system faults is thereby minimized by the use of protection relays. The speed, sensitivity, reliability and functionality of protection relays necessary to fulfill the social demand for higher power quality have a close relationship to the power system configuration and the individual operation of the power system. In Japan, continuous progress has been made in the development of protection relay technology to solve the various difficulties caused by the increasing complexity and expansion of power systems. As a consequence, the protection relays employed by Japanese power companies have individual specifications suited to the respective needs of each power system.
This technical report describes the results of a systematic survey particular to the protection relays used by each power company in Japan; (1) Specification of a typical protection relay system, (2) Basic concept of power system configurations including the protection relay and its operation.
For comparison, this report provides content related to overseas protection relays; (3) Specification of overseas protection relay systems and trends in relevant standards, (4) Analysis of the differences between domestic and overseas protection relay technology.
This committee is composed of universities, power companies, manufacturers and CRIEPI. This technical report is intended to help not only professional engineers, but also students who will be involved in this area of technology.

©2007. The Institute of Electrical Engineers of Japan