AC voltage withstand test equipment? Wuhan UHV specializes in producingAC withstand voltage testing equipment, with a wide range of product options. When looking forAC withstand voltage testing equipment, choose Wuhan UHV.
The AC withstand voltage test of various large power transformers, power cables, steam turbines, hydro generators, and other capacitive equipment must be strictly conducted regularly in accordance with the test regulations. Under power frequency conditions, due to the large capacitance of the test object or high requirements for the test voltage, there are also high requirements for the power capacity of the test device. In order to ensure the safe and reliable operation of the cable, relevant international standards have made clear provisions for various tests of the cable. The main test items include measuring insulation resistance, DC withstand voltage, and leakage current. The measurement of insulation resistance is mainly used to check whether the cable insulation is aging, damp, and exposed insulation defects during the withstand voltage test. The DC withstand voltage and leakage current tests are conducted synchronously, with the aim of discovering defects in the insulation. However, in recent years, domestic and international experiments and operational experience have proven that DC withstand voltage tests cannot effectively detect insulation defects in cross-linked cables, and may even cause insulation hazards in cables. There have been multiple cable accidents in China, and a considerable number of cable failures are caused by the negative effects of frequent DC withstand voltage tests. Therefore, relevant departments at home and abroad widely recommend using AC withstand voltage instead of traditional DC withstand voltage.
principle
We know that when the circuit frequency f=1/2 π√ LC, resonance occurs in the circuit, and the voltage on the test sample is Q times the output voltage of the excitation transformer high voltage end. Q is the system quality factor, which is the voltage resonance multiple, generally ranging from tens to hundreds or more. First, adjust the output frequency of the variable frequency power supply to induce series resonance in the circuit, and then adjust the output voltage of the variable frequency power supply under the condition of circuit resonance to achieve the test value of the sample voltage. Due to the resonance of the circuit, a smaller output voltage of the variable frequency power supply can generate a higher test voltage on the test sample CX.
Product features:
1. The required power capacity is greatly reduced, and the power required for the experiment is only 1/Q of the test capacity.
2. Small in size and light in weight, generally 1/3-1/5 of a regular testing device;
3. A resonant power supply is a resonant filtering circuit that can improve the waveform distortion of the output voltage, obtain a good sine waveform, and effectively prevent the accidental breakdown of the test sample by harmonic peaks.
4. The variable frequency power supply has strong protection function and good stability; It has multiple working modes including fully automatic (automatic tuning, automatic boosting), fully manual (manual tuning, manual boosting), and semi-automatic (automatic tuning, manual boosting, and manual tuning, automatic boosting), which can be switched and used freely, and is easy to operate; Adopting 220V or 380V single-phase power supply for convenient on-site power supply.
5. Flexible configuration and strong expansion capabilities. The resonant reactor adopts multiple methods and modular combinations, which can be connected in series or parallel, meeting the testing requirements of various samples and making it more convenient for on-site use.
6. The large screen touch LED LCD color screen and external mouse can directly set various parameters, and the test results can be saved, printed, uploaded, and retrieved.
