The UHV-135kVA/108kV series resonance scheme adopts the method of adjusting the power supply frequency to achieve resonance between the reactor and the test capacitor, thereby obtaining high voltage and large current on the test object. Due to its small required power supply, light weight, and compact size, it has received widespread acclaim and application both domestically and internationally. It represents a new method and trend in high-voltage testing.
The main functions and technical features of our company's frequency conversion resonance device are as follows:
1, Protection Functions: The device is equipped with 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. In case of test object flashover, the flashover protection will activate and record the flashover voltage value for test analysis.
2, Lightweight Design: The entire device is lightweight, making it easy to use on-site.
3, Multiple Operation Modes: The device offers three working modes: fully automatic mode, manual mode, and automatic tuning with manual voltage boosting mode. This allows users to flexibly choose based on on-site conditions, improving test efficiency.
4, Data Storage and Printing: The device can store and remotely print data. The stored data is numbered digitally, making it easy for users to identify and retrieve.
5, Automatic Frequency Sweeping: During automatic frequency sweeping, the starting frequency can be set arbitrarily within a specified range, and the sweeping direction can be chosen as upward or downward. A large LCD screen displays the scanning curve, allowing users to intuitively understand whether the resonance point has been found.
6, DSP Platform Technology: The device uses DSP platform technology, allowing for the addition or reduction of functions and upgrades based on user needs. The human-machine interface is more user-friendly.
7, Reduced Power Supply Capacity: The series resonance power supply generates high voltage and large current through resonance between the reactor and the test object's capacitance. In the entire system, the power supply only needs to provide the active power consumption, so the required power supply capacity is only 1/Q of the test capacity.
8, Reduced Weight and Volume: The series resonance device eliminates the need for bulky high-power voltage regulators and conventional high-power frequency test transformers. Moreover, the resonant excitation power supply only requires 1/Q of the test capacity, significantly reducing the system's weight and volume, typically to 1/10-1/30 of conventional test devices.
9, Improved Output Voltage Waveform: The resonance power supply uses a resonant filter circuit, which improves the waveform distortion of the output voltage, providing a high-quality sinusoidal waveform and effectively preventing harmonic peaks from causing false breakdowns in the test object.
10, Prevention of Large Short-Circuit Currents: In a series resonance state, when the insulation weak point of the test object breaks down, the circuit immediately detunes, and the 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 increases by tens of times. Compared to this, the short-circuit current and breakdown current differ by hundreds of times. Series resonance effectively identifies insulation weak points without the risk of large short-circuit currents damaging the fault point.
11, No Recovery Overvoltage: When the test object breaks down, the high voltage immediately disappears due to the loss of resonance conditions, and the arc extinguishes instantly. The process of re-establishing the recovery voltage is long, making it easy to disconnect the power supply before reaching the flashover voltage again. This voltage recovery process is an intermittent oscillation of energy accumulation, which is prolonged and does not result in any recovery overvoltage.
