In order to accomplish high reliability and maintenance reduction for substation equipment, Fuji Electric proposed a concept of an advanced substation. Research and development thereafter resulted in the practical use of fully gas-insulated substations, highly reliable control systems for substation equipment, and a highly reliable operating mechanism for switchgear. It is expected that optical data transmission networks to connect maintenance support systems, operation support systems, protection systems, and supervision and control systems with each other will be standardized in the near future.

In order to realize the efficient maintenance and operation of its increasing power installations, Chubu Electric Power Co. Inc. started in 1989 to develop the latest substation that can reduce maintenance and inspection labor and shorten outage duration in case of a fault, utilizing up-to-date digital, optical, and sensor technologies. Fuji Electric tackled systems engineering and equipment development jointly with the company.
Chubu Electric Power Co. Inc. and three manufactures including Fuji Electric have completed the first practical substation, Kira Substation, and set it working in June 1993.

There is much demand for the reliability improvement, maintenance labor reduction, and downsizing in medium voltage switchgear.
Fuji Electric has put on the market a newly developed unit suitable for fully gas-insulated substations. The unit has realized improvement in environmental protection by adopting gas insulation, maintenance labor reduction by applying new technology. Reliability improvement with solid-state or optical control circuits, and compactness. The unit is also provided with a fault locator for quick restoration in case of a fault.

The reliability of high-voltage switchgear in substations has been improved by applying gas-insulated switchgear (GIS). Troubles are mostly caused by operating mechanisms and control circuits. Poor contact is the main cause of troubles in control circuits, so electronic control circuit is developed using a programmable controller, sensors, and semiconductor devices. To improve the reliability of operating mechanisms, operating power is reduced by adopting a newly developed interrupting chamber, and a greaseless operating mechanism aiming at maintenance-free equipment is under full-scale model tests.

Since transformers are static equipment, they are reliable intrinsically. With regard to a self-cooled load-tap-changing transformer, it is an essential point to improve the reliability of its load tap-changer, the only control part movable. Fuji Electric has developed a new motor-driving mechanism to drive the load tap-changer (LTC drive). The LTC drive is characterized by the prevention of poor contact error and maintenance-free construction (greaseless and oiling-free) developed under the concept of maintenance labor reduction, equipment reliability improvement, and function enhancement.

Demand for increase in power supply and improvement in power quality increases an amount of equipment in a maintenance man's charge. To meet the situation, Fuji Electric has been developing equipment monitor and maintenance support systems utilizing sensor technology and systems engineering.
This paper describes developments in sensor and signal-processing technologies and examples of a maintenance support system and data editing.

In recent years, power demands have been concentrating in cities and society has come to think much of environmental comfortableness; hence, there has been increasing demands for substation equipment in harmony with environment.
This paper describes Fuji Electric's technical developments in connection with noise reduction, vibration reduction, downsizing, measures to prevent disasters, and designs for exterior views suitable for environmental conditions.

Recent progress in electronics has elevated protection and control technology and system functions year after year in order to supply stable, high-quality electric power.
This paper describes the methods, configurations, and characteristics of the transformer backup protection, busbar protection, busbar separation protection, and VQ control systems provided for substation protection and control which incorporate DUF series digital relays with a 32-bit microprocessor.

Demand for mini-uninterruptible power systems has been increasing to meet the spread of small-computer-applied equipment. Recent demands for smaller size, lighter weight, lower cost, and naturally superior output performance have grown stronger. In addition, importance has been attached not only to output performance, but also to input performance.
Utilizing the latest power electronics, Fuji Electric has developed a small, light, high-performance 1kVA model (M-UPS 01F). This paper introduces its features, specifications, and characteristics.

Remarkable progress in computerized equipment (downsizing and performance improvement) has been intensifying demand for a smaller, lighter, higher performance power system, i.e. mini uninterruptible power system (Mini-UPS).
To meet the demand, Fuji Electric has developed a small, light, high-performance new type Mini-UPS (2kVA, 3kVA, and 5kVA) by adopting a high-frequency insulated SMR converter using an IGBT for the switching element. This paper introduces its specifications, features, circuitry configurations, and test results.

With regard to current leads to supply current to a superconducting coil from an external power source, Fuji Electric has developed the following:
(1)Current lead for fusion devices (30kA, 20kV),
(2)Current lead for short time ratings (transient 100kA),
(3)Current lead for AC use (5kA),
(4)Fin type current lead for accelerators (5kA), and
(5)Current lead incorporating high temperature superconductors (1kA).
This paper introduces their features, configurations, and performance.

With regard to Fuji Electric's developments among superconducting equipment for the fusion reactor under R & D, this paper introduces their outline, placing emphasis on superconducting coils.
Particularly described are the details of the development of an advanced disk type superconducting coil which is expected suitable for large scale coils, and the features, main specifications and characteristics of the large scale superconductor test facility, gyrotron, and superconducting bus-line.