The structure ofvariable frequency series resonancemainly consists of a variable frequency control power supply, excitation transformer, capacitor, and capacitor voltage divider.
The application range ofvariable frequency series resonance:Suitable for various large power transformers, power cables, steam turbines, hydro generators, and other capacitive equipment. The AC withstand voltage test must be strictly conducted regularly according to the test regulations. Under power frequency conditions, due to the large capacitance of the test object or high requirements for the test voltage, there are also high requirements for the power capacity of the test device. Traditional power frequency withstand voltage devices often have large individual volumes, heavy weights, are not easy to transport on site, and are not easy to combine arbitrarily, resulting in poor flexibility.
The principle of frequency conversion series resonance:When the circuit frequency f=1/2 π√ LC, the circuit resonates, and the voltage on the test sample is Q times the output voltage of the excitation transformer high voltage end. Q is the system quality factor, which is the voltage resonance multiple, generally ranging from tens to hundreds or more. First, adjust the output frequency of the variable frequency power supply to induce series resonance in the circuit, and then adjust the output voltage of the variable frequency power supply under the condition of circuit resonance to achieve the test value of the sample voltage. Due to the resonance of the circuit, a smaller output voltage of the variable frequency power supply can generate a higher test voltage on the test sample CX.
The main purpose of variable frequency series resonanceis:
1. The device has protection functions such as overvoltage, overcurrent, zero start, and system detuning (flashover). The overvoltage and overcurrent protection values can be set according to user needs. When the test sample is flashover, the flashover protection action can be taken and the flashover voltage value can be recorded for experimental analysis.
2. The entire device is lightweight and easy to use on site.
3. The device has three working modes, which facilitate users to flexibly choose according to the on-site situation and improve the testing speed. The working modes are: fully automatic mode, manual mode, automatic tuning, and manual boost mode
4. It can store and print data in different locations, and the stored data numbers are numerical, making it convenient for users to identify and search.
5. When the device automatically scans the frequency, the starting point of the frequency can be set arbitrarily within the specified range, and the scanning direction can be selected upwards or downwards. At the same time, the LCD screen displays the scanning curve, making it convenient for users to intuitively understand whether the resonance point has been found.
6. Adopting DSP platform technology, it is convenient to add or remove functions and upgrade according to user needs, making the human-machine exchange interface more user-friendly.
Wuhan UHV specializes in the production ofseries resonance (also known as variable frequency series resonance complete 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.
