This article provides a clear overview of series resonant test equipment!

发布时间：2023-01-05

The series resonant test system is a high‑voltage withstand testing device developed to meet the requirements of large‑capacity test specimens. It is a modular, integrated solution. To ensure smooth and accurate high‑voltage withstand testing and to enhance cost‑effectiveness, the configuration of the series resonant system varies depending on the specific type of test specimen.

What is the difference between a conventional series resonant test setup and a variable-frequency series resonant test setup? The principle of series resonance states that when the capacitive reactance… When the capacitive reactance XC equals the inductive reactance XL—i.e., XC = XL—the voltage U and the current I in the circuit are in phase, and the circuit behaves as a pure resistor. This phenomenon is known as series resonance and is primarily used in the design and manufacture of AC withstand voltage tests for primary electrical equipment in substations rated at 220 kV and below.

The portable variable-frequency series resonant test device is primarily used in the following areas: 1. AC withstand voltage test for 6 kV–500 kV high-voltage cross-linked cables; 2. AC withstand voltage test for generators; 3. AC withstand voltage test; 4. Power-frequency withstand voltage test for 6 kV–500 kV transformers; 5. AC withstand voltage tests for busbars, bushings, transformers, and other high-voltage power equipment.

According to the procedural requirements, the series resonant test apparatus can meet the testing needs of transformers, AC withstand voltage testing of capacitive equipment such as SF6 circuit breakers, GIS systems, bushings, and cables. It can meet the test requirements for both low-voltage, high-current devices and high-voltage, low-current devices, offering broad application prospects and making it an ideal pressure‑testing device for testing engineering organizations.

The main components of a series resonant test system are as follows: the series resonant circuit primarily consists of an excitation transformer, a variable-frequency control power supply, a reactor, and a capacitive voltage divider. Notably, the variable-frequency control power supply is imported. The SPWM digital waveform generator chip offers a frequency resolution of 0.1 Hz within the 20–300 Hz range and a 16-bit frequency resolution. Certain power supplies utilize advanced IPM modules, ensuring high‑quality output waveforms across the entire frequency spectrum and guaranteeing the instrument’s stability and safety.

Main features of the series resonant test system: Compared with similar domestic products, this series of equipment offers several key advantages: 1. Under rated load, the temperature rise is minimal; reactors of the same voltage class and capacity are smaller and lighter. They feature dry‑type epoxy casting, excellent electrical insulation, high mechanical strength, and an aesthetically pleasing, reliable design. 2. The variable‑frequency control power source offers substantial capacity margin, superior output waveform quality, robust protection functions, excellent stability, simple operation, and multiple operating modes. It can be powered by either a 220 V or 380 V single‑phase supply, ensuring convenient on‑site power availability. 3. Flexible configuration: users can select different types of reactors to meet the requirements of various test specimens, enabling multi‑purpose use with outstanding cost‑effectiveness. Compared with traditional test transformers, the variable‑frequency series resonant test system is compact, lightweight, easy to transport, and straightforward to operate, making it highly convenient for field deployment and portability. Moreover, its modular design allows for flexible adjustment of the number of reactors based on site conditions, significantly reducing labor intensity and enhancing operational efficiency.

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