Induced Voltage Triple Frequency Generator - Yangzhou Dary
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Induced Voltage Triple Frequency Generator is designed to meet the requirements of the "Regulations for Preventive Tests of Electrical Equipment" fortriple frequency induced withstand voltage tests and partial discharge tests. The induced withstand voltage test for transformers and instrument transformers is an important test to verify that the product complies with national standards. The longitudinal insulation induction test of interlayer, inter-turn, inter-section, and phase-to-phase insulation of windings is an important item to verify whether the winding meets requirements. To increase the test voltage of the winding without causing over-saturation of the transformer or instrument transformer core and excessive excitation current, the test frequency is increased, typically to 100Hz-400Hz.
There are several methods to obtain a 100Hz-400Hz power supply, among which the most applicable are: ① combination of three variable-frequency generators (100Hz-400Hz); ② combination of three single-phase transformers (150Hz), and the most convenient is the second method.
Combination of three single-phase transformers: the primary is star-connected, and the secondary is open-delta connected. When the core is not saturated, the main flux it produces is necessarily a flat-topped wave. Since the flat-topped main flux contains a significant third harmonic component Φ3, and the frequency of the third harmonic flux is f3=3f1, the main flux induces a third harmonic phase electromotive force.
Since the primary is star-connected and the secondary is open-delta connected, the core operates in a saturated state, and the no-load current I is a peaked wave. In addition to the fundamental component, it contains higher harmonics. Among the higher harmonics, the amplitude of I is relatively large. Due to the open secondary, the three-phase fundamental components cancel each other out, leaving only the third harmonic output.
SFQTriple Frequency Power Supply Generator utilizes the saturation characteristics of the magnetic circuit to extract the third harmonic voltage, which has the largest component among harmonics, as the power supply for the generator. It is used for frequency multiplication and voltage multiplication tests on inter-turn, inter-section, and interlayer insulation of inductive coil-type electrical products such as transformers and instrument transformers, to assess the insulation strength and withstand voltage level of the coils. 
Note: The above information and technical parameters are compiled and released by Yangzhou Dary Electric Co., Ltd.
