Basic concept of frequency conversion series resonance test device
Series harmonics are mainly used for conducting AC voltage withstand tests on power equipment such as cables, main transformers, generators, and CVTs. Therefore, there are cable series harmonic devices, substation series harmonic devices, generator series harmonic devices, and CVT series harmonic devices.
The difference between voltage withstand test and power frequency voltage withstand test of variable frequency series resonance test device
Difference in Capacity and Volume
The traditional method for conducting AC withstand voltage tests on power equipment is the "power frequency (50Hz) withstand voltage method". The conventional capacity of power frequency transformers is several tens of kVA. As the capacity of power equipment (test subjects) continues to increase, there is a higher demand for the capacity of withstand voltage equipment. If only the diameter of the winding wire is increased according to traditional production processes to meet this demand. This will lead to cumbersome manufacturing processes, large volumes, and difficult on-site handling of power frequency transformers. From the perspective of practical on-site applications, this approach is not very realistic.
In response to the above issues, a variable frequency series resonance test device has emerged. The conventional capacity of string harmonic is several hundred kVA, and the maximum is several thousand kVA. The biggest advantage of variable frequency series resonance is its large capacity, which means it has high power and can drive larger loads. That is to say, it can conduct voltage withstand tests on longer cables and larger capacity transformers, generators, and motors. Meet the pressure resistance test of large capacity test samples. At the same time, the volume and weight of the series harmonic will be much smaller compared to the power frequency, making it more convenient to transport.
Differences in Safety Performance of Power Equipment
The protection of power equipment by power frequency withstand voltage test relies on the "hardware+software protection" of the instrument;
The series harmonic withstand voltage test not only relies on "hardware+software protection", but also has a natural protection that when the test sample breaks down, the series harmonic device will destroy the working conditions of the device, causing the series harmonic to "lose resonance", thus achieving the purpose of protecting the test sample. Series harmonic protection is superior to power frequency withstand voltage.
This is like a piece of "ordinary glass" colliding with "tempered glass". When the ordinary glass is damaged, it will have sharp edges and can cause injury; Tempered glass will shatter completely to avoid injury.
Differences in the objects of use
The application of power frequency withstand voltage is generally for power equipment (test objects) with small loads (small capacitance), such as circuit breakers, isolating switches, insulators, and other test objects;
The application of variable frequency series resonant devices is generally for power equipment (test objects) with large loads (large capacitance), such as cables, generators, transformers, CVTs, switches (attached), etc.
Post time:2021-10-25 13:26:10