What does the excitation screen mean, and what is the excitation controller

The provision of a working magnetic field for generators and other generators (electrical equipment that works using the principle of electromagnetic induction) is called excitation. Sometimes a device that provides rotor power to the rotor of a generator is also called excitation.

Excitation is a device that provides stator power to the stator of a generator or synchronous motor. According to the different excitation methods of DC motors, it can be divided into other excitation, and excitation, series excitation, compound excitation, etc., in the rotation process of DC motors, excitation is to control the voltage of the stator to produce magnetic field changes, change the speed of DC motors, and change the excitation also plays a role in changing the speed.

As early as the late 60s, Harbin Electric Machinery Factory, Shanghai Electric Machinery Factory, Dongfang First Motor Factory and other manufacturers successively designed and produced 100MW, 125MW, 200MW and 300MW units. At the same time, with reference to the technology of the former Soviet Union, equipped with AC exciter static rectifier excitation system, in the early 80s, China introduced 300MW and 600MW units of Westinghouse Company of the United States, 300MW units of Harbin Motor Factory still use static rectifier excitation system, 300MW units of Shanghai Electric Motor, 600MW units of Harbin Electric Machinery Factory all use AC exciter rotary rectifier excitation system.

According to the rectification method, it can be divided into two categories: rotary excitation and static excitation. Among them, rotary excitation includes DC AC and brushless excitation; Static excitation includes a static exciter with an electric potential source and a static exciter with a composite power supply.

The screen used to place the generator excitation system.

It's supposed to be pre-excited, right? That is, before the motor starts, the stator coil of the motor is passed with a certain direct current to make the motor establish a certain magnetic field in advance, and then a large starting torque can be obtained when starting!

Prepare for more torque at start-up.

Hello, this function can realize the fast start of the motor.

Friend, the excitation controller is used to control the excitation voltage of the excitation winding on the generator, so as to obtain the smooth shape of the output voltage of the power generation. A controller made of components such as voltage regulator control.

The demagnetization switch is used to prevent the generator from overvoltage when the generator is shut down, when the generator is shut down and the motor outlet switch is broken, because there are still some loads in the original, the rotor is still supplied with a larger working current than the no-load excitation current, when the switch is disconnected, all the excitation current and the increase of the turbine speed caused by the disconnection of the external load, these two parts are all used to establish the voltage, so that the voltage of the generator is higher than the rated voltage, and the generator will have an overvoltage when the demagnetization switch is not put in. Electrical breakdown of the windings. To put it bluntly, it is used for anti-generator overvoltage protection.

Degaussing screen: It is a cabinet used to install demagnetization switches and demagnetization resistors.

Magnetic field rheostat: It is used to adjust the excitation current, that is to say, if the DC circuit wants to reduce the current flowing through Senxian, it can connect a resistor in series, and the magnetic field rheostat is used for this. The demagnetization switch is a two-position two-way switch, which communicates the generator with the DC excitation circuit during normal operation, and communicates with the demagnetization resistance when the generator rotor winding is shut down for dry spring dismantling and discharge.

The magnetic field rheostat is connected in series in the DC excitation circuit.

The power supply and its ancillary equipment that supply the excitation current of the synchronous generator are collectively referred to as the excitation system. It is generally composed of two main parts: the excitation power unit and the excitation regulator. The excitation power unit provides excitation current to the synchronous generator rotor; The excitation regulator, on the other hand, controls the output of the excitation power unit based on the input signal and the given regulation criteria.

The automatic excitation regulator of the excitation system plays a considerable role in improving the stability of the parallel group of the power system. In particular, the development of the modern power system has led to the trend of reducing the stability limit of the unit, and has also promoted the continuous development of excitation technology.

DC classification: The excitation mode of DC motor can be divided into four categories: separate excitation, parallel excitation, series excitation, and compound excitation.

Rectifier classification: rotary excitation.

Rotary excitation includes DC AC and brushless excitation.

2.Stationary excitation.

Stationary excitation includes a static exciter with an electric potential source and a static exciter with a composite power supply.

According to the AC power supply method of generator excitation.

AC excitation (other excitation) system.

Powered by an AC exciter coaxial to the generator. The system can be divided into four ways:

1) AC exciter (magnetic field rotation) plus stationary silicon rectifier (brushed).

2) AC exciter (magnetic field rotation) plus stationary thyristor rectifier (brushed).

3) AC exciter (armature rotation) plus silicon rectifier (brushless).

4) AC exciter (armature rotation) plus thyristor rectifier (brushless).

2.Fully static excitation (self-excitation) system.

The transformer is used for power supply, when the excitation transformer is connected to the machine end of the generator or connected to the factory power bus of the unit generator set, it is called the self-excitation mode, and the excitation converter of the machine end excitation transformer and the generator stator series series is combined to supply power to the generator rotor. There are also four ways to combine this:

1) DC side in parallel.

2) DC side in series.

3) AC side parallel.

4) AC side in series.

By measuring the generator voltage and comparing it with the given voltage, the deviation is calculated according to the PID method, and the control voltage is converted into the corresponding phase shift angle to change the output voltage of the thyristor rectifier bridge and the sub-voltage), so as to achieve the purpose of controlling the generator voltage.