The non-glowing discharge withstand voltage test device is the core testing equipment in the field of insulation performance detection for high-voltage electrical equipment. The most core technical feature of this device is that the local discharge quantity of itself is extremely low under high-voltage output conditions, which can be controlled within 5 picocoulombs (pC) in conventional cases. This characteristic completely avoids the problem of background interference in the test system, ensuring that the local discharge signals obtained during the detection can truly and accurately reflect the actual insulation state of the tested equipment, providing a reliable basis for insulation performance judgment.
With the continuous upgrade of voltage levels in the current power system, the assessment standards for the reliability and stability of power equipment have become increasingly strict. The application value of the non-glowing discharge withstand voltage test device has become increasingly prominent, widely used in key links such as quality control of power equipment manufacturing, on-site acceptance and handover of power projects, and daily preventive maintenance of equipment. It is an indispensable core equipment for the safe operation of high-voltage electrical equipment.
I. Technical Principle and Equipment Classification
Based on different technical routes, the current mainstream non-glowing discharge withstand voltage test devices can be divided into three categories. Each type of equipment has its own structural principle, performance characteristics, and applicable scenarios, which can adapt to the detection requirements of different high-voltage electrical equipment.
(1) Frequency-Variable Series Resonance Type Device
The core working principle of the frequency-variable series resonant type device is the frequency regulation resonant technology. By precisely adjusting the power supply output frequency, the inductance of the reactor and the equivalent capacitance of the tested equipment form a stable resonant circuit. Under the resonant state, the entire circuit exhibits purely resistive characteristics, and the power supply only needs to provide a small amount of active power to compensate for the loss of the circuit operation, while the reactive power can be exchanged cyclically between the reactor and the tested equipment, thereby achieving the effect of high test voltage output with a small-capacity power supply.
This type of device has a compact overall structure, small size, and light weight, with low requirements for on-site power supply capacity, and has extremely strong adaptability. The output voltage of this device is a standard sine wave, with a waveform distortion rate that can be controlled below 3%, and an excellent quality factor, which can significantly reduce energy consumption during the test process. It is mainly used for on-site acceptance tests of power cables, gas-insulated fully enclosed combined electrical apparatus (GIS), generators, large transformers, etc.
(2) Gas-filled Non-glowing Discharge Test Transformer
The gas-filled non-glowing discharge test transformer abandons the traditional transformer oil-paper insulation structure and uses sulfur hexafluoride (SF₆) gas as the core insulation medium. Sulfur hexafluoride gas has excellent insulation performance and arc-extinguishing performance, and the medium itself does not have conditions for local discharge, fundamentally eliminating the interference problem of the equipment’s insulation structure.
The local discharge performance of this type of device is at the industry-leading level. The background local discharge quantity of conventional products can be controlled below 3 picocoulombs, and high-precision models can maintain stable within the range of 1 to 3 picocoulombs. Compared with traditional equipment, it completely eliminates the environmental hazard of oil leakage, and has stronger adaptability to complex on-site environments such as high temperature, high humidity, etc. It is mainly applicable to the factory quality inspection of high-voltage level GIS equipment, gas-insulated transmission lines (GIL), and can also meet the withstand voltage test requirements for 110 kilovolts and above voltage level power transformers and insulation bushings.
(3) Non-glowing Induction Withstand Voltage Device
The non-glowing induction withstand voltage device relies on the excitation transformer to drive the series resonant circuit and is a testing device specifically developed for electromagnetic voltage equipment. This device can output twice the rated frequency high-voltage withstand voltage, effectively avoiding the over-saturation problem of the equipment core during the test, and ensuring the accuracy of the withstand voltage test and local discharge detection results from a technical perspective.
The core function of this device is to detect and verify the electrical withstand strength of the transformer winding insulation, and is mainly adapted to the induction withstand voltage test and local discharge measurement operations of power transformers and voltage transformers of 110 kilovolts to 500 kilovolts and above voltage levels.
II. Core Key Technical Parameters During the equipment selection and practical operation, it is necessary to focus on checking the core technical parameters. Each parameter indicator directly determines whether the equipment can meet the requirements of high-voltage test experiments for different scenarios. The core parameters are as follows:
(1) Partial Discharge Quantity
The partial discharge quantity is the most core and crucial performance indicator of the non-discharge withstand voltage test device. According to industry general standards, the background partial discharge of the device itself should be controlled within 5 picocoulombs. For high-precision and highly demanding detection scenarios, high-precision equipment with a background partial discharge of 1 to 3 picocoulombs or lower should be selected. The lower the background noise of the equipment, the higher the recognition accuracy of the weak insulation defect signals generated by the tested equipment, and the more accurate the detection results will be.
(2) Output Voltage and Capacity
The rated output voltage of the device needs to fully cover the higher standard test voltages corresponding to the tested equipment, and the rated capacity needs to meet the capacitance current demand generated by the operation of the tested equipment. For large-capacity test samples such as long-distance power cables and large-capacity transformers, the device equivalent capacitance value and standard test voltages need to be combined to accurately calculate the reactive power required for the test, so as to determine the appropriate equipment capacity configuration and avoid insufficient test capacity affecting the detection effect.
(3) Frequency Regulation Range
The conventional frequency regulation range of the variable frequency series resonance type device is 30 to 300 hertz. For special structures and materials of niche test samples, a wider frequency regulation range needs to be relied on to precisely match the circuit resonance conditions and meet the various requirements of industry test standards to ensure the smooth conduct of the test.
(4) Waveform Quality and Stability
The output voltage of the equipment needs to be a standard pure sine wave. According to industry general requirements, the waveform distortion rate should be controlled within 3% to 5%; the frequency stability should be better than or equal to 0.05%, which can achieve high-precision stable control of voltage and frequency during the test, avoiding interference to the test data caused by waveform distortion and frequency fluctuations.
III. Application Scenarios and Selection Suggestions
Different types of non-discharge withstand voltage test devices have significantly different performance advantages and applicable scenarios. It is necessary to select based on the detection object and working environment to ensure test efficiency and detection accuracy.
For on-site交接 tests of long-distance power cables， the variable frequency series resonance type device is preferred. Power cables generally have the characteristic of large capacitance， and this device reduces the on-site power supply capacity requirement through the resonance principle， while the device is portable and suitable for various outdoor on-site conditions， with extremely strong on-site practicability.
For the factory test and on-site withstand voltage detection scenarios of high-voltage level GIS equipment， the gas-filled non-discharge test transformer is suitable. This device has an extremely low background partial discharge level， which can accurately capture the tiny insulation defects inside the equipment， meeting the high-precision quality inspection and acceptance standards for high-voltage equipment.
For the induction withstand voltage special tests of power transformers and voltage transformers， a non-discharge induction withstand voltage device is selected. The dedicated multiple-frequency high-voltage output characteristic of the equipment can effectively avoid the problem of iron core over saturation， accurately verifying the withstand performance and operational reliability of the equipment winding insulation.
Post time: Jun-01-2026