The HC Series Variable Frequency Series Resonance Withstand Voltage Test System employs a method of adjusting the power supply frequency to achieve resonance between the reactor and the capacitor under test, thereby generating high voltage and high current across the test object. Due to its low power input requirements, lightweight design, and compact dimensions, this system has garnered widespread acclaim and application both domestically and internationally, representing a modern methodology and emerging trend in the field of High-Voltage Testing.

Features and Advantages

1. The device is equipped with various protection functions, including overvoltage, overcurrent, zero-start interlock, and system detuning (flashover) protection. The protection thresholds for overvoltage and overcurrent can be configured according to user requirements. In the event of a flashover in the test object, the flashover protection mechanism is triggered, and the corresponding flashover voltage value is recorded for subsequent test analysis.

2. The entire unit is lightweight and designed for easy deployment and operation in the field.

3. The device offers three distinct operating modes: Fully Automatic, Manual, and Automatic Tuning with Manual Boosting. Users can flexibly select the most suitable mode based on specific field conditions, thereby accelerating the testing process.

4. The device allows for the storage and printing of test data from various locations. Each stored data record is assigned a unique numerical ID, facilitating easy identification and retrieval by the user.

5. During automatic frequency scanning, the starting point can be arbitrarily set within a specified range, and the scanning direction (upward or downward) can be selected as desired. Simultaneously, the LCD screen displays the frequency response curve, providing a visual aid that allows users to intuitively determine whether the resonance point has been successfully identified.

6. Leveraging DSP platform technology, the system allows for the flexible addition or removal of functions and facilitates future software upgrades based on user needs. Furthermore, the human-machine interface is designed to be highly user-friendly. 7. Significantly Reduced Power Capacity Requirements: The series resonance power supply generates high voltage and high current through the resonance phenomenon occurring between the resonance reactor and the capacitance of the test object. Within the entire system, the power supply unit is only required to provide the active power consumed by the circuit; consequently, the input power required for the test is merely 1/Q of the total test capacity.

8. Substantial Reduction in Weight and Volume: In the series resonance configuration, the need for bulky, high-power voltage regulators and conventional high-power frequency-doubling transformers is eliminated. Since the resonance excitation power supply needs to provide only 1/Q of the test capacity, the overall weight and volume of the system are drastically reduced—typically to just 1/10 to 1/30 of that of standard testing equipment.

9. Effective Improvement of Output Voltage Waveform: The resonance power supply functions as a resonant filtering circuit, effectively mitigating output voltage waveform distortion to produce a pure sinusoidal waveform. This feature also serves to prevent accidental dielectric breakdown of the test object caused by harmonic voltage peaks.

10. Prevention of Damage to Fault Points from High Short-Circuit Currents: Under series resonance conditions, should a dielectric breakdown occur at a weak point within the test object's insulation, the circuit immediately detunes. Consequently, the circuit current rapidly drops to a level of 1/Q times the normal test current, thereby preventing the high short-circuit current from causing further damage or burning out the fault point. When conducting withstand voltage tests using parallel resonance or test transformers, the breakdown current increases immediately—often by several orders of magnitude. In comparison, the short-circuit current and the breakdown current differ by a factor of several hundred. Series resonance enables the effective detection of insulation weaknesses without the concern that large short-circuit currents might burn out the fault point.

11. No recovery overvoltage occurs. When the test object experiences a breakdown due to the loss of resonance conditions, the high voltage vanishes instantly, and the electric arc is immediately extinguished. The process of voltage recovery is quite protracted; consequently, it is easy to disconnect the power supply before the voltage returns to the flashover level. This voltage recovery process constitutes an intermittent, energy-accumulating oscillation that is of relatively long duration and is characterized by the absence of recovery overvoltage.