Synchronous Generator Excitation System Performance and Development

The excitation system is a core component of synchronous generators, and its performance and reliability have a crucial impact on power supply quality, generator stability, and reliability. This article systematically elaborates on the important role and technological evolution of synchronous generator excitation systems from four aspects: composition, development history, performance requirements, and future prospects.

Composition of the Excitation System

During the operation of synchronous generators, the excitation winding requires a direct current (DC) power supply to provide DC current for establishing a constant magnetic field. Based on the generator's external characteristics, the generator needs to adjust the excitation current in real-time to ensure a constant output voltage when the load changes. This task is accomplished by the excitation system, which mainly consists of the following two parts:

1. Excitation Power Source

It provides DC excitation current to the generator's excitation winding to generate a stable magnetic field. The excitation power source is a key part for the generator to establish voltage and regulate output.

2. Excitation Regulator

It adjusts the excitation current according to the operating state of the generator, either manually or automatically, to meet the dynamic demands of system operation. By regulating the output of the excitation power unit, voltage control and system stability are achieved. The excitation system, through monitoring changes in the generator's voltage, current, and other parameters, forms an excitation control system with the generator, providing effective regulation for the generator's operation.

Development History of the Excitation System

The development of the excitation system has evolved from traditional to modern, with technological innovations closely following the increasing demands of power systems and advancements in electronic technology. From early mechanical designs to today's intelligent systems, excitation technology has shown significant innovation and adaptability.

1. Traditional Excitation System

In early excitation systems, the excitation power unit mainly used DC excitation machines, and the regulator was primarily of electromechanical or electromagnetic types. Although these systems were simple and reliable, their regulation speed was slow, and dynamic performance was insufficient, making it difficult to meet the high standards of modern power systems.

2. Semiconductor Excitation System

With the increase in synchronous generator capacity and the widespread application of high-power semiconductor components, excitation systems began to use semiconductor rectifiers as the excitation power unit, equipped with regulators made up of semiconductor components. This system, known as the semiconductor excitation system, has the following advantages:

Fast regulation speed and significantly improved response characteristics.
Simplified system structure and more reliable operation.
Significantly enhanced dynamic performance to adapt to complex operating conditions.

3. Microcomputer Excitation System

In recent years, the rapid development of computer and control technology has propelled the excitation system towards intelligence and integration. The excitation regulator with a microcomputer at its core (hereinafter referred to as the "microcomputer excitation regulator") has been widely applied, with the following features.
 
Simple hardware: Modular design, small size, and high reliability.
Powerful software: Supports complex control algorithms for high-precision regulation and multifunctional operation.
Excellent performance: High steady-state voltage accuracy and dynamic response speed.
Decreasing costs: With technological maturity, its cost-performance advantage becomes increasingly apparent.

Due to its outstanding performance, the microcomputer excitation regulator has been widely used in large generator units both domestically and internationally, showing a broad development prospect.

Performance Requirements of the Excitation System

To meet the high reliability and quality demands of modern power systems, the excitation system should have the following performance characteristics.

Adequate excitation power: Provides sufficient excitation current for the generator during no-load and full-load conditions to meet normal operation requirements.
High dynamic response capability: Rapidly adjusts excitation current in the event of sudden load changes or short circuits in the generator, maintaining stable output voltage.
High steady-state voltage accuracy: Ensures high precision of the generator's output voltage during static operation, avoiding voltage fluctuations that affect the normal operation of electrical equipment.
Strong excitation capability: Provides strong excitation current in a short time when the generator's voltage severely drops or when starting large-capacity asynchronous motors, quickly restoring system voltage to the set value.
Reliability and convenience: The system should have high reliability, maintaining stability under various operating conditions, and features small size, light weight, and ease of installation and maintenance.

Future Prospects

With the increasing complexity of power systems and higher energy efficiency requirements, the excitation system will further develop in the following areas.

Intelligence and digitalization: The introduction of artificial intelligence and big data technology will enable smarter operation state monitoring and optimized regulation in excitation systems.
Higher integration: Integrating excitation regulators, power units, and monitoring systems onto a unified platform to enhance system reliability and convenience.
Green energy-saving technology: Excitement systems will focus more on energy-saving designs, using more efficient semiconductor devices and advanced control algorithms to reduce energy loss.
Modular design: Excitement systems will move towards modular development, facilitating quick installation, maintenance, and upgrades, adapting to diverse application scenarios.

Conclusion

The performance of the synchronous generator excitation system is the foundation for the stable operation of generators and high-quality power supply. With the rapid progress of modern electronic technology, excitation systems have evolved from traditional mechanical and electrical equipment to intelligent microcomputer excitation systems, achieving significant progress in efficiency, precision, and reliability. Looking to the future, excitation systems will continue to develop in the direction of intelligence, digitalization, and energy-saving, providing solid support for technological innovation in the power industry and safeguarding efficient and stable power supply.