Introducing a Practical Guide to Generator Excitation Systems

The excitation system of generators is pivotal in electricity production, ensuring both uninterrupted and stable electricity generation and safeguarding the secure operation of power systems. Understanding the fundamental principles and components of generator excitation systems is essential for optimizing generator efficiency and ensuring system stability. This article provides a comprehensive introduction to these principles, the primary functions of excitation systems, and methodologies for adjusting excitation parameters, aiming to deepen readers' understanding of operating and maintaining this critical system.
 

Basic Principles of Generator Excitation Systems

Understanding the basic principles of generator excitation systems is crucial. The excitation system of a generator generates a magnetic field in the excitation winding through excitation current. The interaction between the excitation magnetic field and the rotor magnetic field induces electromotive force, thus generating output voltage. The main components of the excitation system include:
 

• Excitation power source: Provides excitation current.
• Excitation winding: Generates a magnetic field through excitation current.
• Voltage regulator: Maintains stable output voltage.
• Excitation controller: Monitors and regulates the entire excitation system.

These components work together to ensure the generator can stably output electricity. A thorough understanding of the structure and principles of the generator's excitation system is essential before adjusting excitation parameters.
 

Main Functions of Generator Excitation Systems

The excitation system of synchronous generators typically uses a DC power source to provide DC to the generator rotor winding. The system consists of excitation power units and excitation regulators. The excitation power unit includes rectifiers and their AC power sources, providing DC excitation power to the excitation winding. The excitation regulator automatically adjusts the excitation current output by the excitation power unit based on changes in generator voltage and operating conditions. The entire system constitutes a feedback control system through the excitation regulator, excitation power unit, and generator to meet operational requirements.
 

1. Maintaining Generator Terminal Voltage at a Given Value

When the generator load changes, the excitation system adjusts the strength of the magnetic field to maintain a constant terminal voltage. Maintaining voltage levels is the primary task of the excitation control system for several reasons.
 

Ensuring Safe Operation of Power System Equipment

All operating equipment in the power system has its rated operating voltage and maximum operating voltage. Maintaining the generator terminal voltage at an allowable level is essential for the safe operation of generator and power system equipment. Generator operating procedures stipulate that the operating voltage of large synchronous generators shall not exceed 110% of the rated value.
 

Ensuring the Economy of Generator Operation

Operating the generator near its rated value is the most economical. If the generator voltage drops, the stator current required to output the same power will increase, increasing losses. Regulations stipulate that the operating voltage of large generators shall not be lower than 90% of the rated value; when the generator voltage is below 95%, the generator should operate at a reduced load. Other electrical equipment also has this problem.
 

Improving Voltage Capacity and Stability Requirements

The excitation control system has a significant effect on improving static stability, dynamic stability, and transient stability, which is the simplest, most economical, and effective measure.
 

2. Meeting Load Requirements

The generator excitation system also needs to adjust the generator output voltage according to actual load requirements to ensure current load requirements. This ensures normal operation of load equipment and ensures the safe operation of the power system.
 

3. Improving Generator Efficiency

The generator excitation system can optimize the voltage and current waveforms of the generator output by adjusting the excitation current of the generator, thereby improving generator efficiency. This not only helps reduce energy consumption but also reduces generator losses and maintenance costs.
 

4. Ensuring Stable Operation of Power Systems

The generator excitation system not only ensures stable output voltage of the generator but also enhances the stability of the power system. The generator excitation system can help control the voltage and frequency of the power system and counteract the impact of load fluctuations on the stability of the power system.
 

Generator Excitation Parameter Adjustment

Implementing generator excitation parameter adjustments requires following certain steps and methods.
 

1. Selecting an Appropriate Adjustment Scheme

Choose the appropriate adjustment scheme based on the specific generator model and parameter requirements.
Refer to technical manuals of equipment and guidance provided by manufacturers.
 

2. Setting the Excitation Power Source Reasonably

Ensure that the excitation current and excitation voltage meet the design requirements.
Adjust the output of the excitation power source to operate within a safe and efficient range.
 

3. Adjusting the Voltage Regulator

Adjust voltage regulator parameters to stabilize output voltage within the rated range.
Regularly inspect and maintain the voltage regulator to ensure normal operation.
 

4. Monitoring and Regulating the Excitation System

Real-time monitoring and adjustment of the excitation system through the excitation controller.
Record and analyze operational data to promptly identify and resolve potential issues.
 

5. Regular Maintenance and Overhaul

Regular maintenance and overhaul of the excitation system to ensure normal operation of all components.
Replace aging or damaged components to prevent downtime or performance degradation due to equipment failure.

Generator excitation systems are crucial in electricity production, ensuring stable generator output and enhancing power system safety and stability. Understanding their principles and components optimizes generator efficiency, meeting diverse load requirements. Proper parameter adjustments and regular maintenance improve energy efficiency and equipment lifespan, ensuring reliable electricity production support.