Since the development of information network society demanded high-quality, high-reliability of electric power supply, electric power utilities have rapidly equipped with distribution automation systems to meet the demands. In this paper, distribution SCADA systems now in practical use are classified according to functions and compared in the features. Also it introduces the tendency of the technical development of the automatic meter reading system, load control system, information service for customers and others under development which structure a totalized distribution automation system.

Distribution automation systems utilizing computers have been developed aiming at increasing operation efficiency of distribution networks, labor saving in business, and power supply reliability because of social demands for stable electric power supply.
This paper introduces an outline of the distribution automation computer systems furnished at Ohito Business Office, Numazu Branch and Hitachiomiya Business Office, Ibaragi Branch of The Tokyo Electric Power Co., Inc. in March, 1988, having the merits of a "voice-announcement man-machine system" and "easy maintenance" due to adaptability to the change of equipment.

The Kansai Electric Power Co., Inc. and Fuji Electric, aiming at efficient and reliable operation of distribution networks and shortening of power failure duration, have developed a distribution SCADA system and started demonstrative operation in the actual power system.
The system was designed in line with fail-safe and easy maintemance in principla because it should control the distribution networks including a vast number of equipment over a wide area.
This paper gives an outline of the distribution SCADA system and describes the features of the specification based on the above design philosophy.

Fuji Electric developed a distribution automation system aiming to improve reliability of electric power supply and shortening of operation interval, and delivered it to Nagano, and Toyohashi Business Offices of the Chubu Electric Power Co., Inc. in March, 1987.
These systems were designed with consideration of improved operability, compact hardware, high reliability, and a fail-safe system; especially, the remote terminal units are microcomputerized with superior environmental characteristics such as high tolerance level of temperature rise, water resistance, and surge tolerability for the purpose of withstanding severe climatic outdoor conditions.

The automatic meter reading system which automatically collects measured values at customers over a wide area by means of transmission lines is studied actively toward practical use. Studies of the system were started around 1970, and now various functions, for example, centralized load control and load survey, have been included in it in addition to data collection. Distribution line carriers, private communication lines, telephone networks, or optical fiber cables are used for the transmission line.
This paper describes the system functions, transmission lines, hardware, and problems to be solved with respect to the technical tendency of the systems.

Attempts to prolong the life of aged plants are going on. Also severe operation of frequent start and stop has become usual. Preventive maintenance technology is indispensable in order to maintain stable power supply under these circumstances. This paper introduces the diagnostic technology of remaining life and its actual examples with respect to steam turbines. Also it outlines the aging and maintenance items of principal parts, parts life prediction, and protective monitoring technology with respect to turbogenerators.

Recently, various preventive maintenance and diagnostic techniques for substations have been developed on the basis of advanced sensor and data processing technology. Monitoring systems for equipment take a leading part in them.
This paper describes the necessity of monitoring systems for equipment, and an outline of preventive maintenance and diagnostic techniques for substations, particularly transformers and switchgear, developed by Fuji Electric so far.

Since maintenance work allotted to staff increased in unmanned substations and plants are becoming old, higher efficiency and higher grade of maintenance and improvement of equipment reliability by preventive maintenance technology have been expected.
This paper outlines the GIS monitoring system at Imabari Substation of Shikoku Electric Power Co., Inc. which monitors GIS conditions automatically in a on-line mode and the measuring equipment of characteristics of circuit breaker (CB-MEC) developed by joint study with The Chubu Electric Co., Inc. which is portable and useful for patrol inspection.

Yasuji Shimizu Masayuki Sekimoto Hironobu Naito

High-voltage rotating machines are playing an important role in various industrial fields. Recently, the proportion of old machines used for many years, for example, 10 years or even over 20 years, has increased, and therefore, need for their insulation diagnosis has greatly increased.
This paper describes an outline of insulation deterioration, the basis of diagnosis, and Fuji Electric's insulation diagnostic system developed from it and put into practical use, and also introduces a few recent studies on insulation diagnosis.

The supervisory control system for substations demands a multifunctional system and high performances in information quantity, contents, and speed. Since conventional cyclic digital transmission telecontrol equipment is difficult to meet these demands, The Chubu Electric Power Co., Inc. and Fuji Electric have jointly developed intelligent telecontrol equipment (ITG). This paper introduces the transmission system, system configuration, and intelligent functions, and the high-precision clock device necessary for accurate timing signals as well.