Understanding DC High-Voltage Generators for Electrical Testing

DC high-voltage generators are specialized testing devices designed to produce high direct current voltages for various electrical testing applications. These sophisticated instruments are essential for assessing the insulation strength of power equipment and conducting research on high-voltage phenomena. According to industry standards, they're primarily used for DC withstand tests on equipment like power cables, capacitors, and other electrical apparatus with significant capacitance.

Technology and Working Principles

Modern DC high-voltage generators employ advanced PWM high-frequency pulse width modulation technology and utilize high-power IGBT components along with imported electronic parts for enhanced reliability :cite[1]. The systems incorporate high-voltage multiplier circuits and implement voltage feedback systems to significantly improve output stability. The technical architecture ensures precise voltage control with measurement accuracy typically achieving 1.0% (full scale) ±1 digit, with the highest resolution reaching 0.1% kV for voltage and 0.1% μA for current measurements :cite[1].

There are two primary circuit configurations for these systems. Basic rectifier circuits generate voltage through half-wave or full-wave rectification, while more advanced series multiplier circuits connect multiple voltage multiplier stages in series to achieve higher output voltages :cite[3]. These series systems can theoretically reach outputs of 2nUm (where n represents the number of stages), though in practice, the number of stages rarely exceeds five due to increasing voltage drop and ripple with each additional stage :cite[9].

Key Technical Specifications and Standards Compliance

DC high-voltage generators are manufactured to comply with specific industry standards including ZBF 24003-90 and DL/T 848.1-2019 in China, with international equivalents such as IEC 60060-2 governing high-voltage test techniques :cite[1]:cite[2]. These standards establish rigorous requirements for measurement systems used in high-voltage testing, ensuring accurate and reliable results.

Technical parameters vary by model with standard units typically offering outputs ranging from 60kV to 400kV, with current outputs from 2mA to 10mA depending on the specific application requirements :cite[1]. The ripple coefficient is generally maintained at 1.0% or lower, with voltage stability within 0.5% even with line voltage fluctuations of ±10% :cite[1]. Modern units feature intelligent protection systems including low-voltage overcurrent, high-voltage overvoltage, poor grounding protection, and emergency stop buttons, with fault response times in the nanosecond range for critical protection functions :cite[1].

Applications in Power Equipment Maintenance

DC high-voltage generators serve critical functions across multiple industries including electric power utilities, industrial plants, railways, and chemical facilities :cite[1]. Their primary applications include:

• Insulation strength tests on zinc oxide arresters and magnetic blow arresters

• DC withstand voltage tests on power cables with large capacitance

• Insulation testing for transformers, generators, and switches

• Leakage current measurements to assess insulation condition

• Extended applications in industrial processes including electron microscopy and electrostatic spraying :cite[1]

For zinc oxide arrester testing specifically, specialized models incorporate automated testing modes and dedicated 0.75UDC-1mA manual trigger buttons that simplify the measurement process without requiring manual calculations :cite[1].

Safety Considerations and Operational Guidelines

Operating DC high-voltage generators requires strict adherence to safety protocols. Personnel must possess high-voltage testing certification and follow established electrical safety standards :cite[1]. Critical safety measures include implementing two distinct disconnection points in the power supply before it reaches the tester, maintaining appropriate safety distances, and using discharge rods with current-limiting resistors when testing capacitive loads like cables :cite[1].

At voltages of 200kV and above, the DC high-voltage field can create different DC potentials on nearby personnel, potentially causing mild electric shocks if individuals contact each other or grounded objects :cite[1]. Proper discharge procedures for capacitive test objects require gradually approaching the discharge rod to allow for air gap ionization before establishing direct contact and finally connecting the ground wire :cite[1].

Future Trends and Technological Developments

The evolution of DC high-voltage generator technology continues with emphasis on enhanced intelligence capabilities, improved portability, and stricter compliance with evolving international standards :cite[2]:cite[5]. Recent updates to measurement standards, including GB/T 16896.3-2024, reflect the ongoing refinement of requirements for digital recording instruments used in high-voltage tests :cite[8].

Research continues into both isolated and non-isolated DC-DC converter topologies, with transformerless designs gaining attention for their potential to reduce size and weight while maintaining high voltage gain capabilities :cite[6]. As power systems evolve worldwide, DC high-voltage testing equipment continues to adapt with improved safety features, more precise measurement capabilities, and enhanced durability for demanding field applications.