The monitor and control system for a power plant was composed of a supervisory switchboard and independent control units for each function combined together. Recently, the adoption of information and communication systems and digital control devices have advanced the integration of monitor and control systems and size reduction by integrating control devices. Also, improvements in value added in plant operation such as maneuverability and visual recognizability enhancement using multifunctional indicators such as CRT and error monitor with personal computer have been promoted. This paper outlines trends of supervising, control, and protection systems.

Fuji Electric proposes a new control system applied to thermal power plants for utilities in consideration of future technical trends. Digitization has advanced not only in computers and controllers composing control systems but also in devices for clectrical equipment. Therefore, in designing a total control system, careful consideration should be given to the technical trends of these devices.

This control and protection system is supplied to the independent power producer in Taiwan. This paper introduces an outline of the following items: (1) unified digital controller for the electrohydraulic governor (EHG) and automatic voltage regulator (AVR), i.e. the main control functions of the turbine and generator (2) entirely electrified turbine protection system without oil trip system (3) automatic valve test system (4) CRT operation system for the EHG and AVR (5) digital protective relays for the generator.

In recent control systems for thermal power plants, with improvement in the performance of human computer interface (HCI), the application of intelligent HCI, including CRT operation, operation support and maintenance support, has been pushed forward. This paper introduces the boiler control system of a thermal power plant for utilities using a CRT operation system and an integrated boiler control system realizing the optimum operation of two or more non-utility thermal power plants.

Aiming at the space reduction and maintenance labor reduction and automation of monitor and control systems, Fuji Electric developed a digital control system for non-utility power plants and commercialized it as FDICS-G series. Also it developed a one-cycle high-speed vacuum circuit breaker as a cogeneration system protective device to instantaneously isolate the generator from the power system and an islanding generator operation detector to make possible reverse power flow operation to the power system. This paper introduces an outline of these devices and the personal computer MMI system with FDICS-G.

The digitization of control systems for hydroelectric power plants is in progress. Aiming to sharply reduce the cost and number of control panels, Fuji Electric developed a monitor-control-protection-integrated panel composed of a processor integrating conventional control, governor, and automatic voltage regulator functions, a large-screen programmable operation display for human communication interface, and digital multifunctional protective relays. Also it developed a centralized monitor system to improve maneuverability, enhance functions, and reduce maintenance labor, and realized sharp cost reduction.

From among maintenance support systems developed to improve maintenance efficiency in hydroelectric power plants, this paper introduces the plant status display and remote RAS (reliability, availability and serviceability) transmission systems. The plant status display system reduces maintenance work on site by the centralized management of information on generating equipment operation on the personal computer screen. The remote RAS transmission system helps quick restoration by automatically transmitting fault data to the manufacturer when a fault occurs in a programmable controller supplied to the plant.

The application of digital protective relays to generator protection started from hydroelectric power plants and reaches thermal power plants. Citing the digital protective relays applied to generator protection in the 600-MW thermal power plant as an example, this paper describes the protection functions of generator, the dual protective scheme, and hardware configuration.

High-level automation has been applied to monitor and control in various plants; however, still much inspection work by ITV imaging and direct observation is left along with the problems of a burden to the inspector and human errors. This paper introduces examples of monitoring and inspection simplified with image processing technology (detection of oil leakage, spark, steam leakage, and fine carbon particles), examples of functions to prevent wrong recognition (entry of an inspector, change in illumination states, plate shaking, and camera vibration), and the application of neural network technology to image processing.

Combined cycle power generation has become predominant in thermal power plants owing to its high efficiency, manageability to power demands, and superiority from the aspect of environment protection. Because of plant operation restrictions, high speed and reliability are required of the controller of a gas turbine, one of the main components of a combined cycle plant. Fuji Electric has developed a controller to meet the requirements and also its simulator. The simulation and fail-safe tests of 300 items conducted with them produced excellent results with respect to performance and reliability.

The control system coordinating generator excitation and governing systems for improving power system stability is under preparation for practical use. A new control system has been developed from this technology according to the decentralized control theory, and its principal design as well as system controllability analysis has been completed. High-level simulation technology is indispensable to the investigation of this control system and the analyses of various phenomena in a large-scale power system. This paper outlines the new control system development and its analysis environment.