The role of electric railways as the means of rapid, mass transportation becomes more and more important. Fuji Electric's basic concept when considering prospects for electric railways is such that the basic support is "reinforcing transportation capacity," which is supported by "safety" as the base and "reducing total cost" and "friendly to people" on both sides. This paper describes the market trends and Fuji Electric's present status and prospects for technical subjects in line with these four supports in each field of rolling stock and ground facilities.

Fuji Electric has developed a 3-level inverter system using its world-class high-voltage IGBTs (2,000V, 400A). In this system, an inverter individually drives a motor. The new methods for motor control and anti-slip control provide superior acceleration performance and comfortableness, particularly in the rain. Fuji Electric's original low-loss snubber circuit realized high-efficiency, small and lightweight inverters. The controller with self-diagnosis and the inverter without fan accomplished high reliability and easy maintenance.

Recently, with the improvement of passenger services such as air conditioning, high capacity auxiliary power supply for DC electric cars has been in great demand and static inverters have come into use. The market needs these static inverters to be of small size, light weight, low noise, easy maintenance, and low energy consumption. Fuji Electric has developed a new static inverter using a high-voltage insulated-gate bipolar transistor (2,000V, 400A) to meet the above requirements. This paper introduces an outline and test results of the new static inverter.

The main stream of recent traction motors is cage induction motors. This paper introduces the latest technologies of design and manufacturing used in the Shinkansen and commuter trains to meet the customer requirements for traction motors of light weight, high speed, and easy maintenance. Concrete items such as optimum temperature design procedures, frameless stators, aluminum rotors, insulated bearings, long life grease, and heat resistant insulation are described.

To cut down the rising construction cost, the extention of the Sapporo City subway Toho route was planned to have a reduced tunnel section. An essential problem for running the existing trains in this part is to develop a pantograph with a small lay down height and a large operating range. Following various plans and testis on operation stability, functions, life, and maintenance, Fuji Electric completed a pantograph with a lay down height of 170?, the first lozenge pantograph for rigid trolley bars with electrical rails in Japan. This paper introduces the development items, test items, and features of this pantograph.

In the Tokaido Shinkansen, a main artery of railway traffic, transportation capacity is increased by raising its railway schedule density. Nevertheless, the railway load is strongly demanded to have no bad influences on the power system. Above all, a sudden change in reactive power causes a voltage fluctuation in the power system, and so var compensation is a key to increase the transportation capacity. This paper introduces an outline of a self-commutated static var compensator using up-to-date power electronics technology.

The self-commutated static var compensator was equipped in a certain substation of the Tokaido Shinkansen, the first among electric railways. To grasp phenomena and characteristics with this equipment linked to the power system, digital simulation using an electro-magnetic transients program (EMTP) was carried out. The simulation was modeled on the system as faithfully as possible. This paper introduces the model contents and analysis examples, consisting of DC overvoltage phenomena according to power system starting methods, control response characteristics of the equipment, and field train load inrush phenomena.

Railway substations as power supply facilities for electric railways that bear rapid, mass transportation demand high reliability, economy, and harmony with the environment. Their control and protective systems have generally been digitized. This paper outlines railway substation system requirements and technologies to embody them, the transitions of control and protective systems and the latest ones.

Urban electric railways have been introducing regenerative electric cars, which use power regeneration inverters and thyristor rectifiers for effective use of regenerated energy during car breaking. These converters require a natural cooling system; a heat pipe cooling can embody the system. This paper describes how to grasp natural air cooling inside a heat pipe cooled converter and the comparison of heat convection analysis by the finite element method with measurements in the test.

Aiming at improvement in reliability, system function and performance using advanced static devices and automatic monitor and inspection functions, programmable controllers, digital protective relays, and information processing equipment have been introduced increasingly. The information processing equipment is used for storing maintenance data such as past records and inspection results and data for grasp trend of load such as measurements and integrating power consumption. Recently, to make this stored data effectively used by the maintenance section, systems with client-server model processing equipment for make remote terminals possible with ease.

In power control and equipment management systems, advanced functions such as automation of routine work and reinforcement of countermeasuring functions for trouble were achieved, and recently, the introduction of systems aiming to use control data for maintenance positively and to manage maintenance have increased. In the background, the flow of information processing equipment toward open systems and downsizing as well as the needs of the times has greatly contributed to the trend. This paper describes the technical trends of power control and equipment management systems for electric railways and recent examples.