In the demanding field of electrical power systems, the DC High-Voltage Generator is an indispensable instrument for ensuring the reliability and safety of high-voltage electrical equipment. These devices are engineered to perform precise DC withstand voltage tests and leakage current tests on critical assets such as power cables, transformers, generators, and metal oxide arresters (MOA). The evolution of this technology has shifted from traditional bulky designs to advanced, portable, and highly efficient systems that comply with stringent international and industry standards, including DL/T 848.1-2019, the general technical specification for high-voltage test devices.

Core Technology and Design Innovations

Modern DC High-Voltage Generators leverage cutting-edge power electronics to achieve superior performance. Key technological advancements include:

• High-Frequency PWM Conversion: The use of high-frequency pulse-width modulation (PWM) technology and voltage/current double-closed-loop feedback control significantly enhances voltage regulation and load regulation. This results in high voltage stability and low ripple output, ensuring accurate and reliable test results.

• Advanced Circuit Topologies: To achieve an ultra-high voltage gain efficiently, contemporary designs incorporate sophisticated circuits. Research highlights the use of coupled inductors integrated with quadratic boost circuits and voltage multiplier cells (such as the Cockcroft-Walton multiplier network) to achieve a substantial step-up conversion. This approach minimizes power dissipation in magnetic components and reduces voltage stress on active switching devices.

• Modular and Resonant Designs: For high-power applications, a modular approach using multiple full-bridge LLC resonant circuits is employed. This design not only facilitates easier maintenance but also allows power switches to operate with Zero-Voltage Switching (ZVS) and output diodes with Zero-Current Switching (ZCS), boosting overall conversion efficiency to levels as high as 93.9%.

Stringent Compliance with Technical Standards

Adherence to established standards is a cornerstone of reliable high-voltage testing equipment. Reputable DC High-Voltage Generators are designed and manufactured in accordance with a comprehensive set of regulations, which typically include:

• DL/T 848.1-2019: General specification for high-voltage test devices - Part 1: High voltage DC generator (the updated version replacing DL/T 848.1-2004).

• DL/T 474.2-2006: Field insulation test implementation guide - DC high voltage tests.

• GB/T 16927.1: High-voltage test techniques - General definitions and test requirements.

• IEC 61975: High-voltage direct current (HVDC) installations - System tests.

These standards ensure that the apparatus meets strict criteria for measurement accuracy, voltage stability (e.g., within ±1% for durations up to 60 seconds), and operator safety.

Key Features for Modern Applications

Today's generators come equipped with a host of user-centric and safety-oriented features:

• Intelligent 0.75U Function: A dedicated one-touch button that automatically sets the output voltage to 75% of the test value, specifically simplifying the procedure for testing the DC reference voltage of metal oxide surge arresters.

• Comprehensive Protection Systems: Integrated protection mechanisms include zero-position interlock, over-voltage, over-current, and breakdown protection, utilizing nanosecond-level sensors to swiftly safeguard both the operator and the equipment under test.

• Precision and Usability: Features such as smooth voltage adjustment from zero, digital dial switches for voltage setting, high-resolution displays, and compact, portable designs make these instruments both powerful and easy to use in various field conditions.

Conclusion

The technological landscape of DC High-Voltage Generators is defined by a relentless pursuit of higher efficiency, greater precision, and enhanced safety. By integrating advanced power conversion topologies like coupled inductors and LLC resonant circuits, and by strictly conforming to industry standards such as DL/T 848.1-2019, these devices provide an indispensable solution for the power industry's diagnostic and preventive maintenance needs. For any entity dedicated to maintaining the highest levels of grid reliability and equipment integrity, investing in a state-of-the-art DC High-Voltage Generator is not just an operational decision, but a strategic one.