Design of High-Voltage Power Supplies in Electrical Equipment Insulation Testing

The insulation performance of electrical equipment is a key factor in ensuring the safe and stable operation of power systems. As the core equipment for insulation testing, the design quality of high-voltage power supplies directly determines the accuracy and reliability of test results. Insulation testing covers various scenarios such as insulation resistance measurement, withstand voltage testing, and partial discharge detection. Different testing requirements impose diverse demands on the output characteristics, control accuracy, and safety protection of high-voltage power supplies. A reasonable design of high-voltage power supplies requires a deep integration of power electronics technology, automatic control theory, and safety engineering concepts to meet the diverse needs of electrical equipment insulation testing.
1. Design of Output Characteristics of High-Voltage Power Supplies for Insulation Testing
Insulation resistance measurement typically requires DC high-voltage output, with a voltage range generally between 500V and 10kV, and requires measurement accuracy at the nanoampere (nA) level for the output current. The high-voltage power supply design employs a feedback loop composed of high-precision resistive voltage dividers and operational amplifiers. Combined with digital signal processing technology, the voltage output ripple is controlled within 0.1%, ensuring the accuracy of insulation resistance measurement results. In withstand voltage testing scenarios, the power supply needs to provide continuous and stable AC or DC high voltage, with voltage amplitudes reaching tens of kilovolts. At this time, the power supply adopts a phase-shifted full-bridge topology and soft-switching technology to reduce switching losses and improve output efficiency. Meanwhile, the flexible adjustment of the output voltage is achieved through multi-winding transformer design, adapting to the testing requirements of different devices.
2. Intelligent Control and Precise Regulation Design
Modern high-voltage power supplies for insulation testing emphasize intelligent control and precise regulation capabilities. The control system constructed based on programmable logic controllers (PLCs) or digital signal processors (DSPs) can achieve functions such as ramp-up voltage, stepwise adjustment, and automatic voltage reduction. For example, in partial discharge detection, the power supply needs to increase the voltage at a specific slope according to a preset program, maintain stability after reaching the test voltage, and monitor the current signal in real-time. Once abnormal discharge is detected, it immediately triggers the protection mechanism and records the data. In addition, by integrating communication interfaces (such as RS485, Ethernet), high-voltage power supplies can be connected to automated testing systems, enabling remote control and data sharing, and improving testing efficiency and management levels.
3. Safety Protection and Reliability Design
During insulation testing, the safety protection of high-voltage power supplies is of utmost importance. At the hardware level, multiple isolation technologies are adopted, including transformer isolation and optoelectronic isolation, effectively isolating the test circuit from operators and preventing electric shock risks. At the same time, a fast overcurrent protection circuit is designed. When the output current exceeds the threshold, the power supply can be cut off within microseconds to avoid equipment damage. At the software level, multi-level permission management and operation confirmation mechanisms are set up to prevent safety accidents caused by misoperations. In addition, the reliability of the power supply system is enhanced through redundant design and hot backup technology, ensuring stable operation under long-term continuous testing conditions.
4. Modular and Compatibility Design
To meet the insulation testing requirements of different types of electrical equipment, high-voltage power supplies adopt a modular design concept. The power supply system is divided into independent units such as power modules, control modules, and display modules, and each module is connected and communicates through standardized interfaces. Users can flexibly combine modules according to actual testing needs to achieve customized configuration of power output voltage, current, waveform, and other parameters. At the same time, the power supply design fully considers compatibility with various testing instruments (such as partial discharge detectors, insulation resistance meters). Through unified signal interfaces and protocols, an integrated insulation testing platform is constructed, improving the versatility and expandability of the testing system.
The design of high-voltage power supplies for electrical equipment insulation testing needs to comprehensively consider multiple factors such as output characteristics, control accuracy, and safety protection. Through technological innovation and optimized design, high-performance, safe, and reliable high-voltage testing power supplies can be created, providing solid guarantees for the insulation performance evaluation of electrical equipment and contributing to the safe and stable operation of power systems.