Wuhan UHV specializes in producingseries resonance (also known as variable frequency series resonance test device). Next, we will share with you the solution of series resonance without voltage boost.

In order to facilitate the maintenance of the power grid and improve the safety of electricity consumption, high-voltage transmission and transformation equipment is required to undergo AC withstand voltage testing. However, the frequency conversion series resonance test device is a measuring device that achieves high voltage and large capacity, and can be used for power cables, busbars, switches, etc GIS、 Transformers are subjected to power frequency withstand voltage tests, consisting 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 test 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.  

Why doesn'tseries resonanceboost the voltage

There are two main situations when theseries resonance test devicedoes not increase the voltage during withstand voltage testing, such as whether the voltage cannot be increased after finding the resonance point, or whether the voltage cannot be increased during the process of finding the resonance point. By analyzing these two situations, it can be determined whether there is a problem with the series resonance test device itself or if the insulation of the test object is damaged. For example, the first situation is that the insulation layer of the cable is damaged (this possibility is very small, if it is already broken, the resonance point cannot be found), and the second situation is that the reactor you are using is damaged, and this hardware damage will definitely prevent the voltage from rising.

Solution

Usually, the failure to boost the voltage due toseries resonanceis mostly caused by problems in finding the resonance point. The main reason for not being able to find the resonance point is that the capacitance and reactance of the test sample do not match, resulting in resonance conditions exceeding the resonance frequency and causing the resonance point to not be found. Our solution to this situation is: 1. Parallel compensation capacitors in the circuit of the series resonance test device, 2. Adjust the series or parallel connection of the reactor to increase or decrease the inductance. Resonance occurs by changing the LC.  

Another reason for not boosting the voltage is that the overvoltage protection and flashover protection parameters of the series resonant variable frequency power supply are set too small, which causes the test device to be protected during the process of finding the resonance point, thus preventing boosting. There are also individual cases where the ground wire is missed, causing the voltage to rise to half and unable to continue. In this case, the voltage should be stopped and the wiring should be carefully checked before continuing the test.