Diesel Power Plant

an electrical installation equipped with one or several electric current generators driven by diesel engines.

Diesel power plants are divided into two main classes: stationary and mobile. Stationary diesel power plants use four-stroke diesel engines (less frequently, two-stroke diesel engines), with power ratings of 110, 220, 330, 440, and 735 kilowatts (kW). Stationary diesel power plants are classed as average in their power rating if the rating does not exceed 750 kW; large diesel power plants can have a power rating of 2,200 kW or more. The advantages of a diesel power plant are favorable economy of operation, stable operating characteristics, and an easy and quick start-up. The main disadvantage is the comparatively short interval between major overhauls. Diesel power plants are used mainly for servicing areas remote from transmission lines or areas where sources of water supply are limited and where the construction of a steam power plant or of a hydroelectric power plant is not feasible. Stationary diesels are usually equipped with synchronous generators.

The economic efficiency of a diesel power plant is improved considerably if the waste heat of the engine (55 to 60 percent of total heat release in currently available engines) can be used for preheating of fuel and oil or for domestic heating within the power station building or adjacent premises. In diesel power plants with a high power rating (above 750 kW) the waste heat can be used in a heating system serving a whole block or a whole town area in proximity to the power station.

Automatic protection against exceeding maximum or minimum limits for the temperature of cooling water and oil, the oil pressure, and the rotational speed (rpm) is built into diesel power plants; protection is also provided in the event of a short circuit in the line. Three levels of automation for stationary diesels are used: automatic regulation of the rotational speed (rpm) and of the temperature of the cooling water and oil, along with automatic emergency signaling and protection in the event of a breakdown; automatic or remotely controlled start-up and shutdown of the diesel engines, an automatic check of conditions required for connecting load to the line, synchronization with other units and with the power system, and a load connection and load distribution with units operating in parallel; and automatic refilling of the feeder tanks for fuel, oil, and water and of the air feed vessels, an automatic (trickle) charging of start-up batteries and of batteries used in auxiliary operations, and automatic control of the auxiliary equipment.

Mobile diesel power plants are widely used in agriculture and forestry and by expeditions involved with geological exploration. In these applications, diesel power plants can be used as a source of electricity for energy or lighting networks; they can be used as the main, auxiliary, or standby power source. In transportation, diesel power plants are a basic power source (for instance, in diesel-electric locomotives and in diesel ships). In mobile diesel power plants, the high-speed diesels serve as prime movers. A mobile diesel power plant includes the diesel-electric unit itself, spare parts, instruments and accessories, a set of cables for making connections to the load, and fire-fighting equipment. Automated diesel power plants with a power rating up to 10 kW are often mounted on a single-axle truck trailer; power plants rated 20 kW or more are usually installed on two-axle, covered trailers. Such a mobile station comprises not only the diesel-electric unit but also the power distribution cabinet (or panel), a cabinet containing the automatic controls, the remote control console, heating and ventilation equipment, rectifiers, and the storage batteries that feed the automatic controls or automated systems.

The first mobile diesel power plants in the USSR were built in 1934 and were known as diesel trains. Such diesel trains have all the power plant equipment installed on platforms or in cars. The power ratings of diesel trains are 1, 2.5, 4.5, and 10 megawatts.

The electric part of the power plant of a diesel train consists of a synchronous generator delivering a voltage of 3–10 kilovolts, assembled or unitized compartments containing high-voltage leads (overhead leads or cables), distribution equipment for voltages of 230–380 volts (required for lighting and for auxiliary motors of the power plant), the storage battery, and operating power circuits and the battery charger.