|Present State and Trends of Load Supply System Protection Relay Systems|
|Investigating R&D Committee on Present State and Trends of Load Supply System Protection Relay System|
|For power systems in Japan the increase in demand for power, large-scale power sources have increasingly been concentrated and distributed unevenly. Electric power transmission has become larger in scale and more complicated with bulk power transmission, multi-circuit, multi-terminal and others.
On the other hand, with the progress in the liberalization of the electric power industry, business activities need to be further improved in efficiency and the existing equipment needs to be utilized more effectively. Thus, constraints on power system operation are expected to be severer.
In particular, for load supply system protection relays, all phenomena that may occur in various system configurations including types of grounding, such as influence of zero-phase circulating current due to multi-circuit, and melting of small-diameter conductors, must be taken into consideration. For years electric power companies have made efforts to realize the optimum protection function based on the characteristics of the power systems they each own.
For the purpose of contributing to more efficient establishment of equipment and more stable operation of power systems in the future with the understanding of these facts, the Technical Committee on Power Protective Relay of the Institute of Electrical Engineers of Japan set up Investigating R&D Committee on Present State and Trends of Load Supply System Protection Relay System. The committee made surveys on system configurations and fault experiences and protection relay system configurations and actual applications mainly for the load supply systems of the electric power companies for 2 years, from August 2002 to July 2004. Moreover, surveys on various phenomena and measures to handle them, characteristics and issues of protection relay systems, actual state in foreign countries and future trends were also conducted.
This report which presents measures to handle various phenomena specific to load supply systems, efficient equipment configurations based on the measures and other related information can serve as a technical resource for engineers.
©2005. The Institute of Electrical Engineers of Japan