By hvhipot 
In recent years, with the rapid development of the power grid and the advancement of technology. The previous power frequency withstand voltage testing equipment had a small capacity and could no longer meet the requirements of large electrical equipment withstand voltage testing. Moreover, the power frequency withstand voltage testing equipment was bulky, noisy, complex in wiring, and difficult to transport. Therefore, in order to meet the development needs of the power grid, we use a series resonance test device to conduct AC withstand voltage tests on the test samples
Series resonance (also known as series resonance equipment)
We use series resonance for cable AC withstand voltage testing, and as the test involves high voltage, we need to be very careful and pay attention to safety.
1. We need to pay attention to on-site wiring: the test lines in two places must use dedicated test lines and cannot be mixed with other test lines. The first one is the signal acquisition line from the voltage divider to the control host, which uses a coaxial signal line. The second is the insulated high-voltage line, which is a dedicated line connecting the excitation transformer and the bottom of the reactor. The characteristic of this insulated high-voltage line is to ensure that the line will not discharge to the ground, ensuring the safe operation of the entire system.
2. How to choose a power supply: The power supply must be connected to AC220V or AC380V according to the equipment requirements. Connect the A and C terminals of the 220V power supply inlet. 380V must be three-phase 380V and connected to the A, B, and C phases of the power supply input terminal. If 380V is connected to terminals A and C, it may cause damage to the instrument, so we need to pay attention to connecting the power supply.
3. When the reactors are connected in parallel, the test lines connected at the ends of the reactors should not be dragged to the ground to prevent discharge to the ground.
4. Safe grounding: All grounding terminals on the instrument must ensure safe grounding, especially the high-voltage tail end on the excitation transformer, which is easily overlooked.
5. In non emergency situations, the series resonance test device cannot be lowered and stopped by cutting off the power supply. This operation can easily cause damage to the instrument. The wire can only be removed after discharging with a discharge rod.
The above are the precautions for using series resonance. When conducting high-voltage tests, we follow the safety principles of high-voltage testing and must not operate or use the equipment without confirming safety.