Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test equipment). Next, we will share with you the function and principle of the variable frequency series resonance test device.
Function of frequency conversion series resonance test device
The variable frequency series resonance test device is a measuring device that provides large capacity and high voltage in power preventive testing projects. It can be used for power cables, busbars, switches, etc GIS, Transformers and other equipment undergo power frequency withstand voltage tests, which consist of reactors, excitation transformers, compensation capacitors, and main control devices. As the voltage, waveform, and frequency are consistent with the actual operating conditions and the electric field state inside the insulation of the tested object, and the test voltage is higher than the actual operating voltage, the series resonance test device is one of the most rigorous, direct, and effective methods for identifying the insulation strength of electrical equipment. It has decisive significance in determining whether electrical equipment can be put into operation and is also an important means to ensure the insulation level of electrical equipment and avoid insulation accidents.
Principle of frequency conversion series resonance test device
By examining the series resonance test circuit, we know that at a circuit frequency of f=1/2 π√ LC, resonance conditions occur in the circuit. At this time, the voltage on the test sample is Q times the output voltage at the high voltage end of the excitation transformer, Q is the quality factor of the system, and Q value is a quantifier in the series resonance test circuit, which is the voltage resonance multiple. Generally, it is several tens to one hundred or more. By adjusting the output frequency of the variable frequency power supply, the circuit undergoes series resonance. The frequency range of the series resonance test is between 30-300Hz. If it exceeds or falls below this frequency range, the circuit can undergo series resonance adjustment by adjusting the reactance or capacitance. Then, when the resonance adjustment is established, the output voltage of the variable frequency power supply can be adjusted to reach the test voltage value. Due to the resonance of the circuit, the smaller output voltage of the variable frequency power supply can generate a higher test voltage on the test sample CX (CX capacitance of the test sample).