Wuhan UHV specializes in producing series resonance (also known as series resonance cable withstand voltage). Next, we will share with you the application of series resonance tester in the power system.
This series resonance testing device is designed and manufactured for AC withstand voltage testing of 10kV, 35kV, 110kV cables, 110kV and below power main transformers, and bus switches. This reactor adopts multiple independent designs, which can meet the testing requirements of high-voltage and low current equipment, as well as low-voltage AC withstand voltage testing requirements, such as 10kV cables. It has a wide range of applications and is a city and a city. The county-level high-voltage testing department and ideal high-voltage equipment are the units for power installation and maintenance engineering.
The device mainly consists of a variable frequency control power supply, excitation transformer, reactor, and capacitor voltage divider.
Advantages of series resonance in power systems:
1. The required power capacity is greatly reduced. Series resonant power supply uses resonant reactors and capacitors to resonate and generate high voltage and high current. In the entire system, the power supply only needs to provide the portion of power consumed in the system. Therefore, the power required for testing is only the testing capacity. 1 / Q.
2. Greatly reduces the weight and volume of the equipment. In a series resonant power supply, not only is the bulky high-power voltage regulating device and ordinary high-power power frequency testing transformer eliminated, but the resonant excitation power supply only needs to test 1/Q of capacity, thus greatly reducing the weight and volume of the system, usually 1/10-1/30 of ordinary testing equipment.
3. Improve the waveform of the output voltage. A resonant power supply is a resonant filter circuit that can improve the waveform distortion of the output voltage and obtain a good sine waveform, effectively preventing the harmonic breakdown of the sample from being accidentally damaged.
4. Prevent large short-circuit currents from burning out the fault point. In the series resonance state, when the insulation weak point of the sample ruptures, the circuit immediately loses resonance, and the loop current rapidly drops to 1/Q of the normal test current. When parallel resonance or test transformer methods are used for withstand voltage testing, the breakdown current immediately increases by tens of times, and the short-circuit current and breakdown current differ from each other by hundreds of times. Therefore, series resonance can effectively detect insulation weaknesses and prevent large short-circuit currents from burning out the fault point.
5. The overvoltage has not been restored. When the sample breaks down, due to the loss of resonance conditions, the high voltage immediately disappears, the arc immediately extinguishes, and the recovery voltage takes a long time to recover. 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 recover overvoltage.
The main functions and technical characteristics of series resonance:
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 sample flashes, flashing protection can be performed and the flashing can be recorded. Use voltage values for experimental analysis.
2. The whole machine is lightweight, with a maximum weight of no more than 40kg, making it 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 testing speed. The working modes are: fully automatic mode, manual mode, and automatic adjustment manual lifting mode.
4. It can store and print data in different locations. The data number stored in it is a number that facilitates user identification and retrieval.
5. During automatic frequency scanning, the frequency starting point can be set arbitrarily within a specified range. You can choose the scanning frequency direction up and down. At the same time, the LCD large screen displays the scanning curve, making it convenient for users to intuitively know whether they have found the resonance point.
6. By adopting DSP platform technology, it is easy to add or remove functions and upgrades according to user needs, and make the human-machine interface more user-friendly.