Generator Excitation System

Overview

The generator excitation system refers to the power source and its associated equipment that supply the excitation current to a synchronous generator. It primarily consists of two main components: the excitation power unit and the excitation regulator.

Types of Excitation Systems

The generator excitation system can be categorized into several types, including:

DC Exciters

Brushless Exciters

AC Exciters

In recent years, the development and application of new technologies, processes, and components have led to continuous improvements in generator excitation methods. In the field of automatic excitation regulation devices, many new types of regulators have also been developed and widely used.

System Composition

Excitation Power Unit:

Provides DC excitation current to the rotor windings of the synchronous generator.

Excitation Regulator:

Controls the output of the excitation power unit based on input signals and given control criteria.

The excitation system is composed of the excitation power unit and the excitation regulator. The entire system, including the excitation regulator, the excitation power unit, and the generator itself, is known as the excitation system control system.

Main Functions

The main functions of the excitation system include:

1. Maintaining Terminal Voltage Stability:

· Regulates the excitation current according to the generator load changes to maintain the terminal voltage at a set value.

2. Controlling Reactive Power Distribution:

· Controls the reactive power distribution among generators running in parallel.

3. Improving Static Stability:

· Enhances the static stability of generators running in parallel.

4. Improving Transient Stability:

· Enhances the transient stability of generators running in parallel.

5. Field Forced Demagnetization:

· Performs forced demagnetization when internal faults occur in the generator to minimize fault damage.

6. Excitation Limiting:

· Implements maximum and minimum excitation limits according to operational requirements.

Summary

The excitation system is a crucial component of the generator, having a significant impact on the safe and stable operation of the power system and the generator itself. The continuous progress in excitation technology, driven by the development of modern power systems and the trend of reduced stability limits in generating units, is essential for ensuring the efficient, safe, and stable operation of power systems.