unit of 600MW, the largest capacity made by Fuji Electric, was put in commercial operation following a satisfactory trial operation. This unit is an up-to-date, high-efficiency, coal-fired thermal power plant with a large-capacity tandem turbine based on European technology.
It is a highly automated plant that has a complete monitor functions by adopting CRT operation, large displays and a field monitor as well as a full computerized system and digital controllers.
This paper introduces an outline of the plant and its automated control and the result of trial operation.

The steam turbine unit 1 is of a 4-cylinder, tandem compound construction and has the largest capacity for this construction in Japan. In the manufacturing process, the most effort was made to increase thermal efficiency and to stabilize shaft vibrations in the coupled rotor system. As the result of test operation, it was confirmed that the shaft vibrations were below 30μm (p-p) at all the bearing points without a field balancing process, and heat rate at the rated load of 600MW achieved 1,812.6kcal/kWh under the guarantee value of 1,830kcal/kWh.

The 670MVA unit 1 generator put in commercial operation in May 1993 contains new technologies such as improvements in stator core end cooling and stator coil fixing and stress-reduced slots of rotor with a cross section obtained by optimum design. To simplify operation and maintenance, a direct gas cooling system for the stator and rotor and a brushless excitation system have been adopted. The monitoring technic has been improved by the computerized watching of operation.

Increasing importance has been attached to the optimization and effectiveness check of operation and control, environmental protection and preventive maintenance programs in recent large-scale thermal power plants. This paper gives an outline of the monitor and diagnosis system and the operation and maintenance guidance system that Fuji Electric has developed and applied to existing steam turbine plants. The application of these systems is an essential way to realize the high-performance high-reliability operation of steam-turbine plants.

More than 60% of existing thermal power plants are equipped with aged equipment operated more than 100,000 hours, while the operation of these plants is becoming severer. Needs for the improvement of aged equipment is increasing rapidly. Concerning equipment maintenance, Fuji Electric has aimed at preventive or predictive maintenance instead of former post-maintenance and has dealt with innovation works of superannuated equipment. This paper introduces an outline of innovation technology for steam turbines and generators and digitization technology for aged electrical control equipment citing examples.

All one-through boilers in Japan utilize all volatile treatment, which have generally shown a quite good effect of corrosion protection. In some boilers, however, a sharp increase in boiler pressure drop has occurred.
In West Germany, oxygenated water treatment by dosing small quantities of oxygen gas has been applied to many units with excellent results.
The Hokkaido Electric Power Co., Inc. placed an order with Fuji Electric for study on the application of oxygenated water treatment in Sunagawa Power Station No.4 unit scheduled up to 1994. This paper gives an interim report of the study.

The number of hydraulic power plants which need to be remodeled or replaced in future is increasing, and clients' needs tend toward freedom from maintenance, economy, and environ-mental protection.
This paper describes Fuji Electric's preventive steps to be taken to remodel or to replace an existing turbine and generator and their technical characteristics.
The paper is particularly prepared to provide customers with references for their innovation plants.

Requirements for efficient and simplified maintenance in hydraulic power plants have been increasing recently and this has caused a movement to apply knowledge engineering to preventive maintenance that depended on the veteran maintenance staff.
This paper introduces an example of an operation and maintenance support system incorporating an expert system which can be in place of the veteran maintenance staff.

Regarding insulation diagnosis technology for generators in thermal and hydraulic power plants, this paper describes developments in line with the philosophy of plant maintenance, progress in insulating material and actual data of insulation aging and introduces the latest diagnosis.
Especially the change of thermoplastic compound insulation to epoxy thermosetting insulation posed a new problem for insulation diagnosis technology, to which a solution will be be found in the new future. Physicochemical aging diagnosis that can directly estimate the aging situation of insulation materials will be an advantageous means.

The synchronous condenser among voltage stabilizing equipment for power systems is being adopted reconsidering the advantage of a voltage source with large overload capacity. Influences on the environment such as noise and vibration due to a large rotating machine and maintenance labor for brushes, cooling water and lubrication oil were demerits, but these have been overcome by incorporating modern rotating machine technology. This paper introduces a 61.4MVA synchronous condenser for The Tokyo Electric Power Co., Inc. as an example which has realized low noise and vibration and reduction in operation and maintenance labor.