In the daily operation and maintenance, equipment handover testing, and preventive testing of the power system, AC withstand voltage testing is a key link in testing the insulation performance of equipment. With the increasing demand for on-site testing, portable AC resonance testing systems have gradually become the first choice for power workers due to their advantages of small size, light weight, and easy on-site operation. However, facing the dazzling array of products on the market, how to choose a suitable set of equipment? Wuhan UHV Power Technology Co., Ltd., based on years of industry experience, provides professional references for you from the following dimensions.

1、 Clearly define testing requirements and accurately match voltage and capacity

The first step in choosing a portable AC resonance testing system is to clarify the testing object and testing standards. Different voltage levels and capacities of power equipment have vastly different requirements for testing systems. For example, for switches and busbars with voltage levels of 10kV and below, smaller capacity models can be selected; For cables, main transformers, GIS and other equipment with voltage levels of 35kV and above, higher voltage levels and larger capacity systems are required.

The perspective of technical parameters, a properly configured series resonant device typically has a rated capacity range of 75kVA to 10000kVA (customizable), a maximum rated voltage of 800kV (customizable), and a working frequency of 30-300Hz. When selecting a device, users need to accurately calculate the required device capacity and voltage level based on the capacitance and test voltage of the tested object, in order to avoid improper equipment selection that may result in abnormal testing or resource waste.

2、 Pay attention to portability and on-site applicability

Portability is the core consideration in on-site testing. Compared with traditional power frequency withstand voltage equipment, the variable frequency series resonant withstand voltage device has a small volume and light weight, making it very easy to operate and transport on site. The series resonant device of Wuhan UHV pays special attention to this point in its design - the entire device is lightweight, easy to carry, and can be quickly assembled and disassembled on site, making it particularly suitable for frequent power testing in different locations.

 A technical principle perspective, a series resonant power supply utilizes resonant reactors and the capacitance of the test object to generate high voltage and high current through resonance. The power supply only needs to provide the active consumption part of the system, and the required power for the test is only 1/Q of the test capacity. This greatly reduces the weight and volume of the system, which is only 1/10 to 1/30 of that of ordinary test devices. At the same time, the equipment has strong adaptability to the working environment and can operate stably under conditions of ambient temperature ranging -10 ℃ to 40 ℃, relative humidity not exceeding 90% RH, and altitude not exceeding 3000m.

3、 Examine the security protection function

High voltage testing prioritizes safety. An excellent portable AC resonance testing system must have a comprehensive safety protection mechanism. The series resonance device of Wuhan UHV is equipped with various protection functions such as overvoltage, overcurrent, zero position starting, and system detuning (flashover). These functions can effectively protect the safety of the test subject and test personnel during the testing process - for example, when the test subject breaks down, the device can quickly detune, reduce the circuit current, and avoid large short-circuit currents burning the fault point. In the series resonance state, when the weak point of the insulation of the test sample is broken down, the circuit current quickly drops to 1/Q of the normal test current, effectively avoiding equipment damage and safety accidents.

4、 Evaluate technical performance and waveform quality

The waveform quality of the test voltage directly affects the accuracy of the test results. A high-quality portable AC resonance testing system should be able to output pure sine waves with waveform distortion controlled at a low level. The output waveform of the Wuhan UHV series resonant device is a sine wave with a waveform distortion rate of ≤ 1%; Its harmonic content is less than 0.3%, which can effectively protect equipment such as main transformers and generators. As a resonant filtering circuit, this device can effectively improve the distortion of the output voltage waveform and prevent harmonic peaks causing false breakdown of the test sample.

In addition, the control system using advanced DSP platform technology can improve the control accuracy and stability of the device, achieving intelligent control. The equipment usually has multiple working modes such as fully automatic mode, manual mode, automatic tuning, and manual boost mode, making it convenient for users to flexibly choose according to the on-site situation.

5、 Consider the manufacturer's qualifications and after-sales service

When choosing equipment, the manufacturer's technical strength and after-sales service cannot be ignored. It is recommended to choose manufacturers with ISO certification and industry qualifications. Wuhan UHV, as an enterprise deeply engaged in the field of high-voltage electrical measurement for nearly 22 years, integrates scientific research, development, production, sales, and service, and has become a leader in the high-voltage electrical measurement industry. It provides professional technical support and comprehensive after-sales service to users, and can provide customized services according to their special needs.

In summary, selecting a suitable portable AC resonance testing system requires comprehensive consideration of multiple aspects such as voltage level, capacity requirements, portability, safety protection, technical performance, and manufacturer qualifications. Only by clarifying one's own needs and conducting a comprehensive evaluation of all dimensions can one select the ideal equipment that is truly suitable for on-site conditions, ensuring accurate and safe testing.