DC high voltage generator commonly known as direct high voltage

DC high voltage generator (commonly known as "direct high voltage") is an extremely basic and core test instrument in power preventive tests.

Combined with the series resonance devices, transformer testers and other equipment you have systematically understood before, DC high voltage generators play an irreplaceable role in power insulation detection. If series resonance devices are mainly used for AC withstand voltage tests of large capacitance equipment, then DC high voltage generators are more adept at providing stable and pure DC high voltage for high-voltage equipment, specifically used to detect insulation defects and leakage conditions of equipment.

The following is a detailed analysis of the core principles, technical characteristics and applications of DC high voltage generators for you:

⚡️ Core Working Principle

The core task of a DC high voltage generator is to convert ordinary power frequency AC (220V/50Hz) into high-quality, highly stable DC high voltage. Its technical route has undergone obvious iterations:

Traditional power frequency voltage doubling rectification: Early equipment was bulky, obtaining DC high voltage through power frequency transformer boosting and then rectifying and filtering, which was inefficient and heavy.

Modern medium and high frequency voltage doubling rectification (mainstream technology): Modern portable direct high voltage generators generally adopt PWM (Pulse Width Modulation) technology and high-power IGBT devices. It first inverts the power frequency AC into medium and high frequency AC of several kilohertz, then boosts it through a medium and high frequency transformer and obtains DC high voltage through voltage doubling rectification circuits. This "high-frequency inversion - voltage doubling rectification" technical route greatly reduces the volume and weight of the transformer, enabling the equipment to be miniaturized and lightweight, while the output DC voltage has extremely low ripple coefficient and extremely high stability.

⚙️ Core Test Functions

DC high voltage generators are mainly used to conduct the following two types of key tests on high-voltage electrical equipment:

DC withstand voltage test: Apply DC high voltage higher than its rated voltage to the equipment to assess its insulation strength under DC voltage and determine whether there are local defects in the insulation.

Leakage current test: During the process of applying DC high voltage, precisely measure the tiny current flowing through the insulation inside the tested object. The magnitude of the leakage current and its variation pattern with voltage and time are important bases for judging whether the insulation is damp, dirty or aged.

✨ Main Technical Characteristics

Modern intelligent DC high voltage generators have the following significant characteristics:

Portable and stable output: Adopting integrated or split portable design, the total weight of the machine is usually only about a dozen kilograms, which is very convenient for on-site handling. The output voltage stability is high, and the ripple coefficient can usually be controlled at 0.5% or even lower, ensuring accurate test data.

Intelligent and automated: Many new devices adopt AIPWM (Artificial Intelligence Pulse Width Modulation) technology and have fully automatic test modes. For example, for zinc oxide arresters, it can automatically complete boosting, finding the 1mA reference voltage (U1mA), automatically reducing voltage and measuring the leakage current at 0.75 times U1mA with one click, without manual intervention.

Comprehensive safety protection: Built-in multiple protection functions, including overvoltage protection, overcurrent protection, zero-position start protection, poor grounding protection and disconnection protection. Once an abnormality is detected, it can quickly cut off the high-voltage output within microseconds to ensure the safety of personnel and equipment.

Convenient data management: Equipped with a large-screen LCD display, it can display parameters such as voltage, current and time in real time. Built-in perpetual calendar, supports storage of test data, on-site printing and export, facilitating subsequent file management.