Product Details

Triple Frequency Test Transformer

 

Darui Electric recommends



SSF Triple Frequency High Voltage Generator



Used for AC induced voltage withstand test of 35-220kV class transformers and voltage transformers, assessing the graded insulation level of 35-220kV class transformers and voltage transformers.



Detailed introduction of SSF Triple Frequency High Voltage Generator





Product Features 

The triple frequency power generator, triple frequency voltage generator, and triple frequency high voltage generator are designed to meet the requirements of <>, <> and >—1995 for triple frequency induced voltage withstand test and partial discharge test.

The induced voltage withstand test of transformers and instrument transformers is an important test to verify whether the product meets national standards. The longitudinal insulation induced test of interlayer, inter-turn, segment, and phase-to-phase insulation of windings is an important item to verify whether the windings meet requirements. In order to increase the test voltage of the winding without causing over-saturation of the transformer or instrument transformer core leading to excessive excitation current, the test frequency needs to be increased, generally to 100Hz—400Hz.

There are multiple ways to obtain 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 method of three single-phase transformers: the primary side is star-connected, and the secondary side is open delta. When the core is not saturated, the main flux it produces must be a flat-top wave. Since the flat-top main flux contains a large component of third harmonic magnetic energy Φ3, and the third harmonic flux frequency f3=3f1, the main flux induces a third harmonic phase electromotive force.

Since the primary side is star-connected and the secondary side 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 wave, it also contains higher harmonics. Among the higher harmonics, the amplitude of I is larger. Due to the open secondary, the three-phase fundamental components cancel each other out, leaving only the third harmonic output.

The whole machine voltage output is achieved by tuning to resonance under 150Hz power supply. When the voltage increases, a certain squealing sound during resonance is normal.



Technical Parameters of SSF Triple Frequency High Voltage Generator 

Rated capacity: 5-100kVA

Input: three-phase 380V, 50Hz sine wave







Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.