What factors affect the results of thevariable frequency series resonancetest? These uncertain factors include:

1. The influence of test time: As the test process progresses for a long time, the equipment gradually heats up, the equivalent resistance increases, and the Q value also decreases. During the high heat period, this phenomenon is very important. Generally, the equipment needs about half an hour of rest before it can continue to be used.

2. The influence of weather: Under high humidity conditions, the corona loss of wires increases significantly, the interference of surrounding electromagnetic fields increases, and the Q value decreases. When the temperature is high, the equivalent resistance of the circuit increases significantly, and the Q value decreases.

3. The impact of not selecting a good resonance point for high-voltage testing frequency on Q value: It has been found in applications that when the voltage rises close to the test voltage, the voltage rises too quickly, accompanied by large voltage fluctuations, and even causes voltage protection action, which is not conducive to the safety of the equipment. However, if the voltage protection value is set too high, it cannot effectively protect the equipment from overvoltage. Therefore, at 2% of the test voltage, the frequency is usually reduced to a good resonance frequency; Then adjust the frequency again under the condition of not exceeding 40% of the test voltage, and slightly lower it to avoid the above phenomenon.

4. The impact of reactors: The general requirement for reactors is a lossless reactor; If the process is not good, the losses are often significant; In addition, when the reactor is placed on iron plates and other metal components, eddy current losses will occur and the equivalent resistance will increase.

5. The influence of high-voltage leads: When conducting AC voltage tests on a single electrical equipment, due to the small test capacity, the impact of high-voltage leads on the test is not significant. When conducting AC withstand voltage tests on outdoor distribution equipment as a whole, the installation height increases with the increase of voltage level, and the higher the voltage, the longer the high-voltage leads. In general, when the high-voltage lead is longer, the corona loss increases, and the equivalent resistance of the circuit increases. When the stray capacitance is connected in parallel with the measured capacitance, the resonant frequency of the circuit decreases, resulting in a decrease in Q value. The interference of the surrounding electromagnetic field increases, leading to a decrease in Q value. Therefore, in the AC withstand voltage test of high-voltage electrical equipment, corrugated tube high-voltage leads should be used as much as possible.

In thevariable frequency series resonantAC withstand voltage test, in addition to relying on the good performance of the reactor. Various good voltage balancing measures, reasonable wire selection, reasonable test site layout, and reasonable time arrangement should also be taken to maximize the Q value. To reduce the impact of equipment heating on the Q value, measures such as heat dissipation have been taken.