Ultra-low frequency high voltage generator for large generators



The ultra-low frequency high voltage generator (often abbreviated as "ultra-low frequency withstand voltage test device") is a core testing equipment in the power system, specifically used for insulation withstand voltage tests on large capacitive test objects (such as power cables, generators, etc.).

Its core function is to use a 0.1Hz (or lower) ultra-low frequency high voltage signal to replace the traditional 50Hz power frequency high voltage. Under the premise of achieving the same insulation assessment effect, it greatly reduces the volume and weight of the test equipment, making it very suitable for on-site carrying and operation.

The following is a detailed introduction to the core principles, functions, and technical characteristics of this type of equipment:

⚡ Core Working Principle

Alternative to power frequency withstand voltage: When conducting traditional 50Hz power frequency withstand voltage tests on large generators, long-distance cables, and other test objects, due to their extremely large insulation capacitance, a test transformer with huge capacity and extremely heavy weight is required. To solve this contradiction, the power sector adopted the method of reducing the test frequency.

Physical advantages of frequency reduction: According to the principle of capacitor charging and discharging, the lower the frequency, the smaller the charging and discharging energy required per unit time. Reducing the frequency from 50Hz to 0.1Hz theoretically requires only one five-hundredth of the test power supply capacity compared to power frequency equipment. This allows the equipment to be made very lightweight, while still effectively detecting end insulation defects and causing less damage to generator insulation.

Three-level energy conversion: Modern ultra-low frequency high voltage generators typically convert ordinary mains electricity (220V) into the required 0.1Hz ultra-low frequency high voltage AC signal through a three-level energy conversion of "DC power supply -> low-frequency oscillation (digital frequency conversion) -> high voltage multiplication".