Receiving and distribution control systems are indispensable equipment for factories and buildings to fulfills the functions. The progress of information-orientated society and the application of sophisticated distribution control systems demand increasing reliability of power supply systems. Fuji Electric has been made efforts to develop new products of distribution control to meet these market needs. This paper introduces recent new products such as high and low voltage circuit breakers, switches, protective relays, automatic power factor regulators and transformers as major components and FI-Net as networks formed with components.

With an increasing demand for higher reliability of power supply installations in information society, requirements for reliable high-voltage breakers and measures against reduction of the maintenance engineers are becoming intense.
To meet these market trends, Fuji Electric has developed a new vacuum circuit breaker that is highly safe and reliable, easy to use, and easy for protective coordination.
This paper gives an outline of the features, construction, and test results of the new breaker.

From the viewpoint of stable quality power supply and measures against reduction in maintenance engineers, there is an increasing demand for system reliability improvement, preventive maintenance, and maintenance free. Fuji Electric has developed a new intelligent vacuum circuit breaker, which incorporates preventive maintenance functions to monitor the vacuum, an abnormal temperature rise in the main circuit terminals and trip coil breaking and transmission functions to send and receive status and control information in addition to the Auto-VCB functions.
This paper outlines the specifications and functions.

To meet the revision of JIS C 4620 for high-voltage receiving switchgear cubicles, Fuji Electric reduced the insulating barrier size of high-voltage AC load-break switches with fuses used for main isolators and remodeled them to make mounting easier. Further, to raise the load-break capacity, the rated current of a current-limiting fuse mounted on the switch was increased to 75A.
This paper introduces the new switch with a fuse that includes the revision in the standard and other recent technical trends.

Fuji Electric commercialized molded transformers first in Japan in 1975. Since than, the company has acculmulated many experiences being favorably noticed by the market and has made developments and a lineup for them to meet market needs. Concentrating the latest design and production technologies, we have developed new type molded transformers by molding the primary and secondary windings together in a body and completed a lineup of them. This paper introduces an outline of the transformers and lineup.

Fuji Electric previously sold 30- to 225-A frame TWIN BREAKERS with outside dimensions unified to both molded-case circuit breakers and earth leakage circuit breakers. The company has recently developed SUPER-TWIN BREAKERS for upper class 400- to 800-A frames which contain the internal attachment of a full cassette construction that allows later setting and realize higher flexibility. Now Fuji Electric's TWIN BREAKER series has a lineup for all the major frames from 30A to 800A frame and can still more contribute to flexible installation on sophisticated low - voltage switchboards and control boards and reduction in total board cost.

Recent intelligent buildings and highly computerized systems have demanded high-reliability, stable power supply. The TWIN BREAKERS with solid-state overcurrent relay are molded-case circuit breakers and earth leakage circuit breakers made highly intelligent with the latest electronics on the basis of the concept of TWIN BREAKERS and contribute to stable supply of electric power by predictive warning/display and various adjustment functions.
This paper introduces an outline of the features and functions of these new TWIN BREAKERS.

The stable supply of electric power is intensely demanded in advanced information society. It is necessary to detect an abnormality in electric installations and to isolate it against failures caused by its influence. The protective relay (OCR and others) is one of essential devices playing the role.
Recent remarkable progress in electronics has pushed electronics application to protective relays.
Fuji Electric has commercialized general-purpose static protective relays with such a background. This paper introduces an outline of these products.

Under the acute situation of power supply as shown in the lowering of actual supply for contract power, there is a growing tendency of saving energy, and demand for automatic power factor regulators is expected to increase. This paper outlines a newly developed regulator. The features are: (1) Calculationless setting by direct inputting numeric values, (2) Wide voltage input and control voltage rating common to 100- and 200-V circuits, (3) Capacitor control at minimum times of make/break for even and uneven capacitors, (4) Input polarity diagnosis and polarity-inverting function dispensing a wiring change for reversed polarity input.

As machines became larger and had more functions, the control panels have become sophisticated and large in capacity. There is a growing tendency of downsizing and standardizing control panels accordingly. Fuji Electric has commercialized a new type very thin circuit protector to meet these needs.
This is an epoch-making product that has improved in breaking capacity with mounting space reduced compared with the former type and realized common use for both AC and DC circuits with the same type. This paper outlines its target, features, specifications, construction and application.

The FI-Net (Fuji Intelligent Network) includes devices and systems developed so that a data transmission system can be composed easily by means of signal multiplex transmission in supervision, control and protection for the high-voltage and low-voltage electric equipment in factories and others.
FI-Net can easily add a function of transmission to the standard devices such as distribution apparatus, control apparatus and measuring instruments and can make an economical data transmission system.
This paper introduces an outline and features of these products.

With regard to high- and low-voltage electric installations in factories and in the fields of construction work, aiming at energy saving and stable power supply as well as the high functions and reliability of individual devices, demand for information networks to cover these installations is becoming intense steadily.
This paper describes the monitoring and control of system apparatus in electric installations in the field of construction work citing Fuji Electric's monitor and control system for construction-use distribution panels.

A distribution system usually has high- and low-voltage switchboards and a main transformer separately installed. Fuji Electric has developed an epoch-making distribution system that unites them with a transformer as the core.
The construction is such that high- and low-voltage circuit breaker units with an attachment function are fixed to the frames of a transformer designed so as to unite them and no separate switchboards are required. The development aimed to reduce installation space, construction time and total cost and it nearly achieved expected effects.