With the continuous improvement of voltage levels in the power system, the demand for AC withstand voltage testing of capacitive equipment such as cross-linked cables, GIS equipment, and large generators is increasing. The power frequency resonance testing system  has become the mainstream equipment in the field of high-voltage power testing due to its advantages of small power capacity, light equipment volume and weight, and good output voltage waveform. However, facing numerous brands and models in the market, how to scientifically and reasonably choose a resonance testing system that suits one's own needs? Wuhan UHV Power Technology Co., Ltd. provides professional advice from the following dimensions based on nearly 22 years of industry experience.

1、 Clearly identify the type of test sample and accurately match the voltage level

The first step in selection is to clarify the type and voltage level of equipment that needs to be tested in this unit. The capacitance values and withstand voltage levels of different test samples vary greatly, and the required specifications of resonant devices are also completely different. For example, a voltage withstand test can be conducted on a 10kV, 300mm ² power cable. If the length is 1km, a device equipped with a 22kV reactor can be selected; If the cable length increases to 3km or the voltage level is raised to 110kV, a larger capacity model needs to be selected accordingly. For the voltage withstand test of the generator, the device model should be determined based on the capacity and phase capacitance of the generator. When conducting AC withstand voltage tests on 110kV GIS and SF6 switches, a higher voltage level reactor combination is required.

Wuhan UHV suggests that the technical department should first confirm the highest voltage level of the equipment under their jurisdiction before procurement. The equipment specifications required for a 10kV distribution network and a 110kV substation are completely different. Improper selection not only results in resource waste, but may also lead to abnormal testing.

2、 Pay attention to technical parameters to ensure performance meets standards

The core technical parameters of the resonance testing system directly determine the accuracy and reliability of the experiment. Users should focus on the following aspects:

Output frequency range: Currently, the output frequency of mainstream devices is 30-300Hz, which can adapt to the testing frequency requirements of different types of power equipment.

Waveform quality: A high-quality resonant device should be able to output pure sine waves with a waveform distortion rate of ≤ 1.0%, effectively preventing harmonic peaks causing false breakdown of the test sample.

Quality factor (Q value): The higher the Q value, the greater the voltage amplitude generated during resonance, and the higher the test efficiency. The quality factor of Wuhan UHV equipment can reach 30~90.

Protection function: Complete overvoltage, overcurrent, flashover protection and other functions are indispensable. When the weak point of the insulation of the test sample is broken down, the circuit current should be able to quickly decrease to avoid large short-circuit currents burning the fault point.

In addition, measurement accuracy is also an important consideration indicator. The device adopts a dual chip architecture of DSP+FPGA and dynamic frequency tracking algorithm, which can control the resonance frequency error within ± 0.05Hz and greatly improve the testing accuracy.

3、 Consider usage scenarios and consider environmental adaptability

The usage environment of the equipment directly affects the selection decision. For units with high frequency of outdoor use, it is recommended to choose models with dust-proof and waterproof shells; In the cold winter environment of northern regions, wide temperature screen models should be selected to avoid slow response of LCD screens. For outdoor construction sites without mains power, it is also necessary to consider the battery life of the equipment and, if necessary, backup generators or high-capacity mobile power sources.

The series resonant device of Wuhan UHV has strong adaptability to the working environment, and can operate stably under the conditions of ambient temperature -10 ℃~40 ℃, relative humidity ≤ 90% RH, and altitude ≤ 3000m.

4、 Evaluate the strength of manufacturers and attach importance to after-sales service

Equipment procurement is not just about buying products, but also about buying services. Users should comprehensively consider the manufacturer's production experience, quality control system, and industry reputation when selecting. A comprehensive after-sales service system is equally important. Operation training after equipment arrival, technical support during use, regular calibration and replacement of vulnerable parts are all important components of equipment lifecycle management.

5、 Reasonably prepare the budget and select configurations as needed

The price of the series resonant withstand voltage test device varies greatly due to differences in brand, range, and accuracy. Economic products are suitable for daily testing of 10kV distribution equipment; The standard type covers voltage levels 35kV to 110kV, with data storage and communication functions, and is the most commonly purchased specification by power supply companies; The high-precision type is used for metrological verification and precision measurement, and the price is usually more than twice that of the standard type.

Wuhan UHV experts remind that procurement costs are only a part of the total cost of ownership, and later costs such as calibration, maintenance, and replacement should also be included in the budget considerations. The delivery time for regular models is generally 7 to 15 working days, while customized specifications may take 20 to 30 working days. It is recommended to prepare a procurement plan in advance.

Choosing a suitable power frequency resonance testing system requires comprehensive consideration of multiple dimensions such as voltage level matching, technical parameter performance, environmental adaptability, manufacturer strength, and budget cost. Wuhan UHV Power Technology Co., Ltd., with its rich product line, excellent product quality, and comprehensive service system, can provide professional solutions for power testing of different voltage levels and application scenarios, helping the safe and stable operation of the power system.