LC series resonance principle? Wuhan UHV specializes in the production of series resonance, with a wide range of product selection and professional electrical testing. To find series resonance, choose Wuhan UHV.
The series resonant voltage withstand device, also known as the series resonant voltage withstand device, mainly consists of a frequency converter controller, excitation transformer, high-voltage reactor, high-voltage voltage divider, etc. Using the principle of series resonance, the excitation transformer is used to excite the series resonant circuit, adjust the output frequency of the frequency converter controller, and make the circuit inductance L and the test sample C resonate in series. The resonant voltage is the voltage applied to the test sample.
The variable frequency series resonance test device, also known as series resonance, is composed of a variable frequency power supply, excitation transformer, reactor, and capacitive voltage divider. The capacitor and reactor of the test sample form a series resonant connection; The voltage divider is connected in parallel to the test sample to measure the resonant voltage on the test sample and provide an overvoltage protection signal; The frequency modulation power output is coupled to the series resonant circuit through an excitation transformer, providing excitation power for series resonance.
Principle
We know that when the circuit frequency f=1/2 π√ LC, resonance occurs in the circuit, 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.
Currently, we have developed many detection instruments using the principle of series resonance, including series resonance test devices, cable variable frequency series resonance test devices, substation variable frequency series resonance test devices, and resonant boost devices for CVT inspection.
According to the principle of resonance, we know that when the inductance value X1 of the current reactor L is equal to the capacitance value Xc in the circuit, the circuit reaches resonance state. At this time, only the circuit resistance R consumes active power in the circuit, while reactive power oscillates back and forth between the reactor and the capacitor of the test sample, thereby generating high voltage on the test sample.
The conditions for generating series resonance:
X L =X C
Due to the high voltage generated by series resonance in L and C, it may cause damage to the breakdown of coils or capacitors. Therefore, in power engineering, series resonance should be avoided as much as possible, and it is particularly important to use series resonance testing devices to detect power systems.
Series resonance characteristic
1. High stability and reliability. The system adopts imported power components as the core of power conversion, with stable voltage and frequency output, reasonable electromagnetic compatibility design, and complete protection functions. After multiple high-voltage direct to ground short circuit tests, the system still remains intact, and at the same time, the system also has strong overload capacity
2. The automatic tuning function is powerful. When the system is automatically tuned, it automatically scans from 30Hz to 300Hz and displays the sweep curve, allowing users to intuitively see the tuning process of the system; After the frequency sweep is completed, the system performs a fine frequency sweep with a resolution of 0.01Hz within its ± 5Hz range based on the resonance frequency point preliminarily found by the sweep, and finally precisely locks the resonance frequency
3. Support multiple experimental modes. The system supports test modes such as "automatic tuning+manual voltage regulation", "automatic tuning+automatic voltage regulation", "manual tuning+manual voltage regulation", etc. It is recommended to use the "automatic tuning+manual voltage regulation" mode, which can quickly find the resonance point and control the test process through manual voltage regulation, with higher safety
4. The system has a user-friendly human-computer interaction interface. The experimental parameter settings, experimental control, and experimental results are displayed on the same screen, which is intuitive and clear, and has automatic timing and operation prompt functions. Full touch screen operation and display, with the function of saving and querying test data
5. The protection function is complete. Equipped with zero position protection (prohibiting system startup when the voltage output control knob is not in zero position), overvoltage protection, overcurrent protection, flashover protection and other functions, ensuring the reliability of the system