Thunder impact high-voltage generator

1、 Core Definition and Technical Principles

Lightning overvoltage is one of the common operating conditions in power systems, characterized by rapid voltage rise, high peak value, short duration, and the ability to instantly penetrate equipment insulation and cause faults. The core definition of a lightning impulse high-voltage generator refers to a specialized high-voltage testing equipment that uses technologies such as capacitor energy storage, resistor voltage division, and spark gap discharge to generate lightning impulse voltage waveforms that meet the standards of the power industry, simulate the electromagnetic environment when lightning strikes equipment, and evaluate the insulation tolerance of the equipment.

The technical principle is based on the "Marx circuit" energy storage and discharge mechanism, which is currently the mainstream way of generating impulse voltage: through a rectifier circuit composed of multiple high-voltage silicon stacks, the power frequency AC power supply is converted into DC high voltage, and multiple sets of series connected energy storage capacitors are charged in parallel to store sufficient electrical energy in the capacitors; When the capacitor voltage reaches the set value, the control triggering system sequentially breaks down the spark gaps at all levels, and the series capacitors instantly switch to a series discharge state. By matching the parameters of the wave head resistance and wave tail resistance, a standard lightning full wave with a rising edge of 1.2 μ s and a wave tail of 50 μ s or other specific waveform impulse voltage is formed at both ends of the test sample. Throughout the process, the measurement system synchronously collects voltage waveforms and response data of the test sample, and determines whether there are defects in the equipment insulation through waveform analysis - if the insulation is intact, the waveform is stable and distortion free; If there are weak links, phenomena such as voltage drops and waveform abnormalities may occur.

2、 Core Structure and Design Highlights

The lightning impact high-voltage generator adopts a modular hierarchical structure, and the various components work together to achieve energy conversion and waveform control. The core components include five major systems. The energy storage charging system consists of a high-voltage rectifier, a current limiting resistor, and multiple sets of energy storage capacitors. The capacitors are made of high-frequency high-voltage polypropylene capacitors, which have excellent temperature resistance and insulation performance. The single unit capacity is usually 0.1-1 μ F; The triggering system is divided into two modes: automatic and manual. The automatic triggering adopts photoelectric triggering technology, with a triggering accuracy of 1 μ s, ensuring the synchronization of gap breakdown; The waveform control system controls the voltage rise speed through the wave head resistance (tens to hundreds of ohms), and the wave tail resistance (thousands to tens of thousands of ohms) determines the wave tail attenuation time. With the help of a tuning inductor, multiple waveform switching can be achieved; The measurement system consists of a high-voltage voltage divider, oscilloscope, and data acquisition card. The voltage divider has a voltage division ratio error of ≤ 1%, and the oscilloscope bandwidth is ≥ 1GHz to ensure accurate waveform capture; The safety protection system is equipped with high-voltage interlocking, overcurrent protection, emergency stop button, and infrared warning is set up in the test area to ensure the safety of personnel and equipment.

The design highlights are reflected in three aspects: first, high waveform accuracy. By optimizing the Marx circuit parameters and using high-precision waveform modulation components, the waveform parameter deviation is controlled within ± 3%, meeting strict testing standards; Secondly, the energy is controllable and adopts a graded energy storage design. The voltage of a single-stage capacitor can reach 50-200kV, and the peak value of the impulse voltage can be flexibly adjusted by increasing or decreasing the number of stages (from several hundred kV to several MV); Thirdly, it is easy to operate. Modern models are equipped with intelligent measurement and control systems, which can complete parameter settings, charging, triggering and other operations through touch screens. Waveform data is automatically stored and analyzed, greatly reducing the difficulty of operation.

3、 Core functions and significant advantages

The functional design of the lightning impact high-voltage generator meets the testing requirements of high-voltage equipment, and its core functions combine professionalism and practicality. The waveform generation function supports multiple standard waveforms such as 1.2/50 μ s lightning full wave, 1.2/20 μ s cutoff wave, and 250/2500 μ s operation wave. Some models can customize waveform parameters to meet the testing requirements of different devices; The energy regulation function achieves precise control of impact energy by changing the charging voltage and the level of energy storage capacitors, and is suitable for various test objects from low-voltage cables to ultra-high voltage transformers; The data processing function can display the impact waveform in real time, automatically calculate key parameters such as peak voltage, wave head time, and wave tail time, and generate test reports that meet the standards; The remote control function supports remote operation through Ethernet or dedicated software, avoiding exposure of test personnel to high voltage environments.

Compared to traditional testing equipment, its advantages are extremely prominent: firstly, the test scenario is realistic, and the generated impulse waveform is highly consistent with the natural lightning overvoltage, which can effectively expose the hidden defects of equipment insulation; Secondly, the testing efficiency is high, with a single impact test taking only a few seconds. Coupled with an automatic control system, batch testing can be achieved, greatly improving production quality inspection efficiency; Thirdly, it has a wide range of adaptability and can achieve voltage coverage from 100kV to 10MV through module combination, meeting the needs of devices with different voltage levels; The fourth is strong security, with multiple security protection mechanisms and remote operation design to reduce the risk of high-voltage testing.