Wuhan UHV specializes in producing series resonance (also known as series resonance withstand voltage equipment). Next, we will share with you the advantages of series resonance withstand voltage equipment?
Traditional high-voltage test transformers, due to capacity limitations, cannot meet the needs of AC withstand voltage tests for high-voltage and large capacity electrical equipment in power systems. This article systematically introduces a new set of variable frequency series resonance test equipment developed based on the principle of circuit resonance. The application of the variable frequency series resonance test equipment in various electrical equipment AC withstand voltage tests was studied, and the following main conclusions were obtained:
1. The complete set of frequency conversion series resonance test equipment has high safety (advantages)
Especially in the AC withstand voltage test of GIS, as GIS is installed after being transported to the site, it may be affected by the on-site environment and may become damp or have foreign objects, resulting in a decrease in internal insulation performance and frequent discharge. GIS is a fully enclosed structure, and when discharge occurs, it is difficult to determine the location of the discharge. Multiple pressurization is required to locate the discharge point. If other AC voltage withstand test devices are used for testing, after multiple discharge shocks, the test device is easily damaged, and the back electromotive force generated by the test sample during discharge can easily cause harm to the operator. The frequency conversion resonance test equipment is used for testing. When discharge occurs, the resonance conditions are not met and the voltage drops to a very low level, which will not cause damage to the test sample and operators.
2. The complete set of frequency conversion series resonance test equipment requires a small power capacity (advantage)
In the current AC withstand voltage test of electrical equipment in substations, the required current of the power supply should not exceed 150A. This device is very suitable for use in power engineering. Practice has proven that using a complete set of variable frequency series resonance test equipment for AC withstand voltage testing is feasible and effective. The variable frequency series resonant power supply generates high voltage and high current through resonance between the resonant reactor and the tested capacitor. In the entire system, the power supply only needs to provide the active consumption part of the system. Therefore, the required power supply for the test is only 1/Q of the test capacity, greatly reducing the required power supply capacity. In the variable frequency series resonant power supply, not only is the bulky high-power voltage regulating device and ordinary high-power power frequency test transformer eliminated, but it is generally 1/3-1/5 of the ordinary test device.
3. Improving the waveform of output voltage with a complete set of frequency conversion series resonance test equipment (advantages)
The resonant power supply of the variable frequency series resonant AC withstand voltage test device is a resonant filtering circuit that can improve the waveform distortion of the output voltage, obtain a good sine waveform, and effectively prevent the false breakdown phenomenon of harmonic peaks on the test sample. Therefore, the frequency conversion resonance test method will be comprehensively applied in the voltage withstand test of power systems.
4. The complete set of frequency conversion series resonance test equipment can prevent large short-circuit currents from burning the fault point (advantage)
In the series resonance state, when the weak point of the insulation of the test sample is broken down, the circuit immediately disengages and the loop current rapidly drops to 1/Q of the normal test current. However, when conducting voltage withstand tests in parallel resonance or test transformer mode, the breakdown current immediately increases by several tens of times. Compared with the two, the short-circuit current is hundreds of times different from the breakdown current. So, series variable frequency resonance can effectively identify insulation weaknesses without the concern of large short-circuit current burning the fault point.
5. The complete set of frequency conversion series resonance test equipment will not experience any recovery overvoltage (advantage)
When the test sample breaks down, due to the loss of resonance conditions, the high voltage immediately disappears, the arc immediately extinguishes, and the process of re establishing the recovery voltage is long. It is easy to disconnect the power supply before reaching the flashover voltage again. This voltage recovery process is an intermittent oscillation process of energy accumulation, which is long and does not result in any recovery overvoltage.
6. The complete set of equipment for frequency conversion series resonance test has a wide range of applications
The variable frequency series resonant device is suitable for AC withstand voltage testing of various electrical equipment. It is not only suitable for AC withstand voltage testing of individual equipment such as power transformers, current transformers, and circuit breakers, but also particularly suitable for distribution equipment GIS, The AC withstand voltage test of large capacity electrical equipment such as cross-linked polyethylene cables, the larger the capacity of the electrical equipment, the better the effect. Widely used in industries such as power, metallurgy, and petrochemicals, it is suitable for the handover and preventive testing of high-capacity and high-voltage capacitive samples.
7. Advantages of the complete set of frequency conversion series resonance test equipment in cable withstand voltage testing
The frequency conversion series resonance scratch test device is mainly designed and manufactured for on-site AC withstand voltage testing of cables and all electrical main equipment with voltage levels of 10kV-110kV. Usually, reactors are designed with multiple separate units, which can meet the requirements of high-voltage and low current equipment testing conditions, as well as low-voltage AC withstand voltage testing requirements such as 10kV-35kV voltage levels. They have a wide range of applications and are ideal AC withstand voltage testing equipment for high-voltage testing departments of provincial, municipal, and county-level power supply companies and power installation and maintenance engineering units.