Induced Voltage Triple Frequency Generator Manufacturer - Yangzhou Darui

Induced Voltage Triple Frequency Generator Manufacturer - Yangzhou Darui

Published: 2020-08-26 09:17:19

Category: Induction Withstand Voltage Test Device

Product Description

Induced voltage triple frequency generator manufacturer

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The triple frequency generator is used for testing power transformers, voltage transformers, and other test objects. In addition to performing external power frequency high voltage tests on the main insulation of fully insulated transformers, it is also necessary to conduct induced high voltage tests on the longitudinal insulation of transformers and the main insulation of semi-insulated transformers.

Basic Introduction Edit

According to national test standards, the induced test voltage for power transformers and voltage transformers is approximately 2-3 times the maximum working phase voltage. As is well known, at rated frequency and rated voltage, the transformer core is close to saturation. If a power frequency power source is used to apply a test voltage greater than the rated voltage across the windings of the transformer under test, the no-load excitation current will increase sharply to an unacceptable level. From the relationship of induced electromotive force, it can be seen that in order to apply a test voltage greater than the rated voltage without saturating the core, the method of increasing the power frequency can be adopted, and a generator with a frequency greater than the power frequency must be used.

Working Characteristics Edit

Reliable performance, can well meet the needs of induced withstand voltage tests for transformers and instrument transformers.

Main Parameters Edit

1. Input voltage: three-phase 380V, 50Hz;

2. Output voltage: 50—500V (max 750V), 150Hz;

100—1000V (max 1500V), 150Hz;

Basic Principle Edit

This product is designed to meet the triple frequency induced withstand voltage test and partial discharge test in the "Regulations for Preventive Tests of Electrical Equipment".

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

There are multiple methods to obtain a 100Hz-400Hz power supply, among which the more applicable ones 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 magnetic flux it produces must be a flat-top wave. Since the flat-top main magnetic flux contains a large component of third harmonic magnetic energy Φ3, and the third harmonic magnetic flux frequency f3=3f1, the main magnetic flux induces a third harmonic phase electromotive force.

Since the primary side is star-connected and the secondary side is open delta, 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 SFQ triple frequency power 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 source for the generator. It is used for frequency doubling and voltage doubling tests on inter-turn, inter-segment, 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 Darui Electric Co., Ltd.

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Product Details

Induced Voltage Triple Frequency Generator Manufacturer - Yangzhou Darui