Principle and basic knowledge of generator and turbine gener

2018-11-05

　　Characteristics of diesel generating set: what is diesel generating set? In the words of two teachers, the diesel engine is used to drive the generator, and the energy of diesel oil is converted into electric energy. According to its different uses, it can be divided into land diesel generator set and marine diesel generator set.

　　1. the basic principles of operation:

　　This is essential for diesel engines to drive generators. The energy of diesel is transformed into electric energy. In the cylinder of diesel engine, the clean air filtered by air filter is fully mixed with the high-pressure atomized diesel fuel injected from the injector. Under the pressure of the piston upward, the volume is reduced and the temperature rises rapidly, reaching the ignition point of diesel fuel. Diesel oil is ignited, the mixture burns violently, the volume expands rapidly, and pushes the piston down. It is called "work". Each cylinder works in a certain order, and the thrust acting on the piston turns into the force driving the crankshaft to rotate through the connecting rod, thus driving the crankshaft to rotate. If the brushless synchronous alternator is coaxially installed with the crankshaft of the diesel engine, the rotating of the diesel engine can drive the generator's rotor. By using the principle of electromagnetic induction, the generator will output the induced electromotive force, and the current can be generated through the closed load loop. The basic principle of the generator set is described here. In order to obtain usable and stable power output, a series of diesel engine and generator control, protection devices and circuits are needed.

　　Structural analysis of 2. diesel generating set:

　　A common diesel generating set is mainly composed of three parts: diesel engine, generator and control system. There are two kinds of connection modes between diesel engine and generator. One is flexible connection, i.e. connecting the two parts with a coupler, the other is rigid connection, and connecting the steel connector of generator and the flywheel of diesel engine with high-strength bolts. At present, the diesel generating units in the market use more rigid connections. After the diesel engine and generator are connected, they are installed on the common chassis, and then equipped with various protective sensors, such as water temperature sensors, through which the operation status of the diesel engine can be visually displayed to the operator. And with these sensors, you can set an upper limit. When the limit is reached or exceeded, the control system will warn in advance. If the operator fails to take measures, the control system will automatically shut down the unit. This is the way the diesel generator sets take to protect themselves. Sensors play the role of receiving and feeding back all kinds of information. It is the control system of diesel generating set that really displays these data and performs protection function. The control screen is usually installed on the generator, which is called backpack control screen. Some parts of the control screen are placed in the operating room independently, which is called split control screen. Connect the cable, generator and sensor to show the electrical parameters and the operating parameters of the diesel engine respectively. In addition, there are chassis, coupling, radiator, fuel tank, and some are equipped with muffler and hood.

　　A generating unit driven by a hydraulic turbine can be called a hydroelectric generating set. Different from the natural conditions of hydropower stations, the variation range of capacity and speed of hydro-generating units is quite different. Usually, small hydro-generators and high-speed hydro-generators driven by impact turbines mostly adopt horizontal structure, while large and medium-sized generators mostly adopt vertical structure. Because most hydropower stations are far away from the city, they usually need to supply power to the load through a long transmission line. Therefore, the power system puts forward higher requirements for the operation stability of hydro-generators: motor parameters need to be carefully selected; rotor inertia needs to be greater. Therefore, unlike the turbogenerator described in the previous article, the hydro-generator has a large diameter and a short length of rotor. It takes a short time to start and connect to the grid, and has flexible operation and dispatch. Besides general power generation, it is especially suitable for peak shaving units and accident standby units. According to the current technology, the maximum capacity of the hydro generating set has reached 700 thousand kilowatts.