Three-frequency generator device load capacity and compensation due to test object



The three-frequency generator device (also known as the three-frequency induced withstand voltage test device) is a core testing device specifically used for induced withstand voltage tests on transformers, voltage transformers, and other equipment in the power system.

Its core function is to accurately assess the longitudinal insulation strength between turns, layers, sections, and phases of power equipment windings by raising the power frequency (from 50Hz to 150Hz) and applying a higher test voltage, without damaging the core of the test object.

Currently, three-frequency generators on the market are mainly divided into two categories: traditional electromagnetic type and modern electronic type (multi-frequency). The following is a detailed comparison and introduction:

⚡ Core Working Principle

Traditional electromagnetic type (three-frequency): Based on the principles of electromagnetic induction and harmonic superposition. It usually consists of three single-phase transformers (or adopts a three-core five-column structure), with the primary side connected in a star configuration and the secondary side connected in an open delta. By raising the voltage to saturate the iron core magnetic circuit, utilizing the nonlinear characteristics of the silicon steel sheet magnetization curve, the zero-sequence third harmonic (150Hz) is induced and superimposed on the secondary side, thereby outputting a three-frequency voltage.

Modern electronic type (multi-frequency): Adopts advanced power electronics technology and full digital control (such as frequency converters and DSP chips). It abandons the bulky iron core saturation principle and directly synthesizes and outputs test voltages at multiple frequencies such as 50Hz, 100Hz, 150Hz, and 200Hz through digital technology, with higher waveform quality.