The XZB series variable frequency series resonance withstand voltage test device adjusts the power supply frequency to achieve resonance between the reactor and the tested capacitor, thereby obtaining high voltage and large current on the tested object. Due to its small required power supply, light equipment weight, and compact size, it has been widely praised and applied both domestically and internationally, making it a new method and trend in high-voltage testing.
The main functions and technical features of our company's frequency modulation resonance device are as follows:
1. The device has protection functions such as overvoltage, overcurrent, zero-position start, and system detuning (flashover). The overvoltage and overcurrent protection values can be set according to user needs. When the test object flashes over, the flashover protection operates and records the flashover voltage value for test analysis.
2. The entire device has a very light single-piece weight, making it convenient for on-site use.
3. The device has three working modes: fully automatic mode, manual mode, and automatic tuning with manual boosting mode, allowing users to flexibly choose according to on-site conditions to improve test speed.
4. It can store and print data remotely. The stored data numbers are numeric, making it easy for users to identify and retrieve.
5. When the device automatically sweeps frequencies, the starting frequency can be set arbitrarily within a specified range, and the sweep direction can be selected upward or downward. Meanwhile, the large LCD screen displays the sweep curve, allowing users to intuitively see whether the resonance point has been found.
6. It adopts DSP platform technology, which can add or upgrade functions according to user needs, and the human-machine interface is more user-friendly.
7. The required power supply capacity is greatly reduced. Series resonance power uses the resonance reactor and the capacitance of the test object to generate high voltage and large current. In the entire system, the power supply only needs to provide the active power consumption part, so the required power is only 1/Q of the test capacity.
8. The weight and volume of the equipment are greatly reduced. In the series resonance device, the bulky high-power voltage regulator and ordinary high-power power frequency test transformer are omitted. Moreover, the resonance excitation power supply only needs 1/Q of the test capacity, greatly reducing the system weight and volume, generally 1/10-1/30 of ordinary test devices.
9. Effectively improves the output voltage waveform. The resonance power supply is a resonant filter circuit that can improve the waveform distortion of the output voltage, obtaining a good sine waveform and effectively preventing false breakdown of the test object due to harmonic peaks.
10. Prevents large short-circuit currents from burning the fault point. In the series resonance state, when the insulation weakness of the test object breaks down, the circuit immediately detunes, and the loop current rapidly drops to 1/Q of the normal test current. In contrast, when using parallel resonance or a test transformer for withstand voltage testing, the breakdown current immediately rises dozens of times. Comparing the two, the short-circuit current and breakdown current differ by hundreds of times. Series resonance can effectively find insulation weaknesses without the concern of large short-circuit currents burning the fault point.
11. No recovery overvoltage will occur. When the test object breaks down, due to the loss of resonance conditions, the high voltage immediately disappears, the arc is instantly extinguished, and the recovery voltage rebuilding process is very long, making it easy to disconnect the power before reaching the flashover voltage again. This voltage recovery process is an intermittent oscillation process of energy accumulation, which is long and does not produce any recovery overvoltage.
Main technical parameters
1. Rated capacity: 75kVA
2. Rated voltage: 25kV; 75kV
3. Rated current: 3A; 1A
4. Measurement accuracy: system effective value class 1.5
5. Working frequency: 30-300Hz
6. Device output waveform: sine wave
7. Quality factor: device's own Q≥30 (f=45Hz)
8. Waveform distortion rate: output voltage waveform distortion rate ≤1%
9. Input power: single-phase 220V or three-phase 380V voltage, frequency 50Hz
10. Working time: continuous 60min allowed under rated load; overvoltage 1.1 times for 1 minute
11. Temperature rise: after continuous operation for 60min under rated load, temperature rise ≤65K
12. Protection functions: overvoltage, overcurrent, zero-position start, system detuning (flashover) and other protection functions.
13. Ambient temperature: -20℃ to 55℃
14. Relative humidity: ≤90%RH
15. Altitude: ≤3000 meters
