This paper discusses electrical plant and systems technology in basic material industry and heavily equipped industry that are major in industrial structure such as iron and steel, nonferrous metals, pulp and paper, synthetic fiber and film, oil refinery, chemicals, cement, and glass industry. It also gives an outlook on environmental change around these fields and the technical trends of basic technologies in these fields such as control technology, plant engineering, information systems, power electronics and power conversion systems, and substation systems.

Attention has been given to H∞ control theory that can handle a multi-input and multi-output system in the frequency area and can design a control system taking plant variation into consideration. The H_∞ control has a possibility of meeting higher control requirements in application to objects beyond the control capacity limit of former technology. This paper gives an outline of the theory and describes an application to a motor system with the motor and load elastically connected by a shaft and an application to a loop length control system in bar mills.

Support systems to secure productivity improvement and high quality have been indispensable for recent electrical plant engineering remarkably rich in software. This paper gives the contents and effectiveness of concurrent engineering capable of directly improving productivity, and an outline of data repository it is based on and actual examples. As for substantial improvement of quality, the other target of the support system, it gives an example of descriptive language for specifications, an outline of the simulation system, and an example of project management system supplementary to the support system.

Fuji Electric established integrated systems of electrical control (E), instrumentation (I), and computer (C) to be used in general industrial plants. Corresponding to the E-I-C ratio of a plant, the company is ready to supply an EIC, EC, IC, or EI integrated control system of which hardware and software are each standardized taking over the technology and experience of each plant control system.
This paper describes basic points in structuring an integrated control system and an outline of the key components.

Recent plants have made a rapid progress in functions and speed with the development of computers and controllers, and they demand advanced operation monitors. The part played by man-machine interfaces becomes more important and various support functions to help operators and maintenance persons are required. This paper gives an outline of operation-monitoring systems with CRT display used in the fields of substations, iron and steel plants, DC arc furnaces, and processing lines.

The progress of information society demands higher power quality and the change in social conditions and living environment such as increase in labor cost and awareness of environmental protection strongly demand labor-saving maintenance and equipment in harmony with environment.
The development of related systems such as sensing and digital systems are necessary to constitute new substation systems. This paper introduces preventive maintenance systems, digital protective systems with protection, control and transmission functions, and compact spot network systems using gas-insulated equipment and molded transformers.

Recent variable-speed drives in the industrial world have changed from DC machines to AC machines. In particular, the inverter is the mainstream in variable-speed systems.
With the progress of semiconductor power devices, various inverters of a large-capacity transistor type, IGBT type and GTO type have been produced in series and mostly used for energy saving in pump and blower drives and for automated systems.
This paper describes inverters arranged in new series and examples of their applications.

Fuji Electric has delivered 11 units of observer-controlled GTO inverters using DC link diode converters for bar mill drive, resulting in power factor and rolling characteristic improvement. Also it has developed a system easy to operate, software with high control performance, and a comfortable operator-friendly control room. Loop control based on the H_∞ control theory is characterized by high robustness and quick response, which will eliminate misrolling due to mill speed setting error. This paper introduces the variable-speed AC drive, advanced control, information and control system used for the rod and section mills.

Various electric power conversion systems are used in industrial plants. Semiconductor devices have made remarkable progress in capacity, functions, and control such as PWM control recently, which has enhanced the performance of converters and widened the scope of their application. More and more importance is attached to their performance and reliability from a viewpoint of productivity improvement. This paper describes recent technical trends of a power supply for steel-making arc furnaces, a large-current DC power supply for electrolysis, and small-capacity DC power supplies citing Fuji Electric's examples of application.

Various electron devices have been used as loads in power supply networks, the energy base of social life, showing a sharp change in capacity. High-quality power supply by compensating for disturbances appear on power networks is demanded more strongly than before. Above all, reactive power including high harmonics is an important factor that affects power quality and how to compensate for this is a key technology to keep or improve power quality. This paper outlines typical reactive power compensation technologies laying emphasis on equipment utilizing latest semiconductor technology, citing Fuji Electric's examples.

The development and practical use of high-performance semiconductor elements has made possible manufacturing power supplies to meet various frequency and power required by different heating conditions and capacities. Fuji Electric has manufactured many high-frequency power supplies of 0.1 to 500kHz and 10 to 8,000kW for various induction heaters. Since induction heaters are heating means satisfying rationalization, quality improvement, and environmental protection now socially required, their use will spread more and more in future. This paper describes application of induction heaters and power supplies Fuji Electric has supplied.