What is compensation equipment in power system ?

    Compensation equipment in power systems is mainly used to improve power quality, improve voltage stability and increase power factor, thereby optimizing system efficiency and reducing losses. The role, working principle and types of compensation equipment are as follows:

1. Role

    1. Improve power factor: In power systems, loads usually contain inductive components (such as motors, transformers, etc.), which causes the current to lag behind the voltage and reduce the power factor of the system. Low power factor means more reactive power, requiring more current to transmit the same active power, increasing line losses and equipment load. Compensation equipment reduces the system's reactive demand on the power grid by providing reactive power and improving the power factor.

    2. Voltage regulation: Compensation equipment can stabilize the voltage in the system and prevent voltage fluctuations, especially when high-power equipment is started and stopped, compensation equipment can play a role in voltage support.

    3. Reduce losses: By reducing reactive power transmission, compensation equipment reduces the current of the transmission line, thereby reducing power losses and improving the transmission efficiency of the system.

    4. Reduce the risk of equipment overload: Compensation equipment reduces reactive power transmission in the system, reduces the load of equipment such as generators and transformers, and extends the service life of the equipment.

2. Working Principle

    The working principle of the compensation equipment is mainly to adjust the voltage and power factor in the system by providing or absorbing reactive power. Reactive power is the electrical energy generated by inductive or capacitive loads. It cannot be directly used to do work, but the balance of reactive power in the power system is crucial to the stable operation of the power grid. The compensation equipment balances the impact of inductive or capacitive loads on the system by exchanging reactive power with the power grid.

3. Types

Compensation equipment can be divided into the following categories according to different functions and working principles:

1. Static VAR compensator (SVC):

- Working principle: SVC dynamically adjusts the reactive power in the system by adjusting the operating status of reactors and capacitors. The injection or absorption of reactive power is adjusted by thyristor rectifiers and filters to quickly respond to changes in system voltage.

- Function: SVC is mainly used to quickly respond to voltage fluctuations and is widely used in high-voltage transmission systems.

2. Shunt capacitor:

- Working principle: The shunt capacitor group offsets the reactive power generated by the inductive load by providing capacitive reactive power and improves the power factor.

- Function: Mainly used to improve the power factor in the distribution system, suitable for inductive loads that run for a long time.

3. Series capacitor:

- Working principle: The series capacitor is directly connected to the transmission line to compensate for the inductive reactance of the line and reduce the reactive power consumption of the line.

- Function: Improve the transmission capacity of the transmission line, reduce line losses, and is suitable for long-distance transmission systems.

4. Static synchronous compensator (STATCOM):

- Working principle: STATCOM is based on power electronics technology and controls the injection or absorption of reactive power by adjusting the output voltage of the inverter. Compared with SVC, STATCOM has a faster response speed and can maintain reactive power compensation function at low voltage.

- Function: Mainly used for dynamic voltage regulation and reactive power control, especially for distributed power sources such as wind farms and photovoltaic power stations.

5. Synchronous phase condenser:

- Working principle: Synchronous phase condenser is a rotating mechanical equipment that can provide reactive power according to demand, and controls the output of reactive power by adjusting the excitation current of the rotor.

- Function: It can continuously provide stable reactive power and is widely used in high-voltage transmission systems and power plants.

    The compensation equipment in the power system improves the power factor, stabilizes the voltage, and reduces power loss by providing or absorbing reactive power. Common compensation equipment includes shunt capacitors, series capacitors, SVC, STATCOM, and synchronous phase condensers.