By hvhipot 
Most peers know that high-voltage electricity needs to be transmitted to users, and high-voltage cables or overhead lines must be used. Short distance or urban electricity transmission often uses high-voltage cables to transmit electricity. Although there is a dedicated cable trench for laying, which is less affected by temperature environment and has high power supply reliability, there are also many uncontrollable factors (such as insulation degradation of the cable itself and transient overvoltage of the line) that can cause faults in the cable during use, such as cable head breakdown. The cable head needs to be remade and passed the withstand voltage test before power can be supplied.
How to make the circuit resonate?
Method 1:
Adjust the frequency of the signal series resonance US to be equal to the natural frequency inside the circuit (the frequency of charging and discharging capacitors and inductors).
Method 2:
Adjust the size of L and C values. The method used for high-voltage cable withstand voltage testing is to adjust the frequency of the power supply end, so that the frequency emitted by the signal generator is transformed by the excitation transformer and becomes equal to the natural frequency in the circuit, causing resonance and increasing the voltage at both ends of the capacitor by many times the voltage at both ends of the transformer. This voltage is then applied between the cable core and ground wire, and maintained for a period of time. If the cable is not broken down, it indicates that the cable is qualified. The voltage at both ends of the capacitor needs to be collected to facilitate the adjustment of the test voltage, which requires the use of phase separation capacitors for collection. Phase separation capacitors are composed of many capacitors connected in series, and only small signal voltages are collected and sent to the frequency adjustment device (signal generator). After internal processing and calculation by the frequency modulation equipment, the test voltage applied to the cable core wire at this time is calculated to facilitate the adjustment of the test voltage by the testing personnel.
HV Hipot Electric Co., Ltd. specializes in producing series resonance (also known as series resonance withstand voltage equipment) and has been engaged in the electrical measurement industry for many years. Its products have first-class quality and welcome customers to come and purchase.