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. According to national testing standards, the induced test voltage for power transformers and voltage transformers is generally considered to be 2-3 times the maximum working phase voltage. As is well known, when a transformer operates at rated frequency and rated voltage, the iron core is close to saturation. If a test voltage higher than the rated voltage is applied across the windings of the transformer under test using a power frequency source, 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 higher than the rated voltage without saturating the iron core, the method of increasing the power supply frequency can be adopted, and a power source with a frequency greater than the power frequency must be used.

Alternative names edit

Triple frequency induced withstand voltage device, triple frequency generator, triple frequency induced voltage generator, triple frequency test transformer device, triple frequency induced withstand voltage generator, triple frequency test transformer, triple frequency tester, triple frequency induced withstand voltage tester, triple frequency power generator.

Purpose edit

SBF adopts a three-core five-column structure, selecting the working magnetic flux density of the iron core above the saturation magnetic flux density, so that the vector sum of the fundamental electromotive forces (positive sequence vectors) in the secondary winding connected in an open delta is zero, while the two ends of the open delta output the same-phase 150Hz third harmonic (zero sequence).

Characteristics edit

Simple operation, reliable performance, and can well meet the needs of induced withstand voltage testing for transformers and instrument transformers.

Working principle edit

It adopts power electronics technology, and the internal core part uses a frequency conversion regulator. Parameter presetting, protection settings, frequency selection, voltage regulation control, etc. It adopts a touch operation mode, and can preset test frequencies of 50Hz, 100Hz, 150Hz, 200Hz (optional), with touch adjustment of voltage (step size can be adjusted in real time, selectable as 1V, 2V, 5V, 10V), enabling the device to output multi-frequency test voltages.

Built-in LC filter circuit ensures that the waveform distortion rate is within the specified range.

Since the traditional three-phase five-column triple frequency generator principle is abandoned, the following advantages are brought:

1. Small size, light weight, easy to carry, and convenient for high-power applications.

2. Not only can it generate triple frequency, but it can also produce test voltage outputs at 1, 2, 3, and 4 times the frequency.

3. Simple operation and wiring, and greatly reduces the requirements for on-site test power supply capacity