ZXSBF : Principle, Parameters and Application in Power Industry

In the power system, the insulation performance of high-voltage electrical equipment is the core guarantee for the safe and stable operation of the power grid. Among various insulation detection methods, the frequency-multiplied induced over-voltage withstand test is an essential technical means to evaluate the dielectric strength of transformers, especially for series-excited high potential transformers with voltage levels of 35-220kV. The ZXSBF Third-harmonic Generator, as a specialized test equipment designed for this test, plays an irreplaceable role in the insulation detection of power transformers. This article will elaborate on its working principle, technical indicators, functional characteristics and practical application scenarios, providing a comprehensive technical reference for relevant technical personnel.

一. Working Principle of ZXSBF Third-harmonic Generator

The ZXSBF Third-harmonic Generator is developed based on the technical requirements of the frequency-multiplied induced over-voltage withstand test. Its core principle is to generate a stable 150Hz third-harmonic power supply by utilizing the non-linear characteristics of the iron core magnetization curve, which effectively solves the problem of iron core saturation when applying high voltage in the power frequency (50Hz) induced test. According to the electromagnetic induction law, the induced electromotive force in the winding is proportional to the rate of change of magnetic flux. For transformers with fixed iron core cross-sectional area and number of turns, increasing the test voltage under power frequency will sharply increase the magnetic flux density, leading to iron core saturation, excessive no-load current and even equipment damage. By increasing the frequency to 150Hz (three times the power frequency), the required magnetic flux density is only one-third of that under power frequency, which can safely apply the test voltage several times the rated voltage while ensuring the stability of the excitation current.

This equipment is mainly used to apply the required induced voltage to the tested transformer, simulate the over-voltage conditions that may occur during actual operation, and further evaluate the insulation performance of the transformer, including the dielectric strength of the main insulation (between windings and ground, between windings) and longitudinal insulation (between turns, between layers, between sections).

二. Technical Indicators of ZXSBF Third-harmonic Generator

The technical indicators of the test equipment directly determine the accuracy and reliability of the test results. The ZXSBF Third-harmonic Generator has excellent performance indicators, which fully meet the technical requirements of the power industry for induced over-voltage withstand tests. The specific indicators are as follows:

1.Input Voltage: It adopts three-phase 380V 50Hz sine wave input, which is consistent with the standard power supply of the power industry, ensuring convenient connection and stable power supply during on-site tests, and avoiding the need for additional power conversion equipment.

2.Output Voltage: The output voltage is adjustable in multiple ranges, including 0-300V, 0-500V and 0-1000V, with a fixed output frequency of 150Hz. The multi-range adjustable design makes the equipment suitable for different types and specifications of transformers, improving the versatility of the equipment.

3.Wave Distortion: The output wave distortion is ≤5%, which meets the relevant standards of the power industry for test power supply waveform quality. The low distortion rate ensures that the induced voltage waveform applied to the tested transformer is close to the actual operating waveform, avoiding test errors caused by waveform distortion.

4.Output Capacity: The output capacity ranges from 0 to 375kVA, which can meet the test needs of series-excited high potential transformers with voltage levels of 35-220kV. The sufficient output capacity ensures that the equipment can stably supply power during the test and avoid voltage drop caused by insufficient capacity.

5.Operation Time: The no-load operation time is ≤5 minutes, and the loading operation time is 40~60 seconds. This time setting is in line with the operation specifications of the induced over-voltage withstand test, which can effectively protect the equipment itself and the tested transformer, preventing damage caused by long-term overload operation.

三. Functional Characteristics of ZXSBF Third-harmonic Generator

Combined with the actual needs of on-site testing in the power industry, the ZXSBF Third-harmonic Generator has the characteristics of simplicity, reliability and strong adaptability, which brings great convenience to technical personnel:

1.Easy to Operate: The equipment adopts a humanized design, with simple operation steps and clear operation interface. Technical personnel can complete the test setup and operation after simple training, which effectively improves the test efficiency and reduces the operation difficulty, especially suitable for on-site rapid testing work.

2.Reliable Performance: The equipment is manufactured in strict accordance with the quality standards of the power industry, with stable electrical performance and strong anti-interference ability. It can work stably in complex on-site environments (such as high voltage, strong electromagnetic interference), ensuring the accuracy and repeatability of test results, which is the key to ensuring the reliability of insulation detection.

3.Strong Adaptability: It is specially designed for the induced over-voltage withstand test of 35-220kV series-excited high potential transformers, and can also be used for the induced voltage test of small transformer windings. In addition, it can be used as a short-time 150Hz power source, realizing multiple functions and improving the utilization rate of the equipment.

四. Application Scenarios in Power Industry

The ZXSBF Third-harmonic Generator is widely used in the insulation detection of power transformers in the power industry, and its main application scenarios include the following aspects:

1.Insulation Detection of Series-excited High Potential Transformers: It is mainly used for the frequency-multiplied induced over-voltage withstand test of 35-220kV series-excited high potential transformers. Through the test, the dielectric strength of the transformer is evaluated, potential insulation defects (such as air bubbles, impurities, cracks, moisture or aging) are found in time, and the safety and reliability of the transformer in actual operation are ensured.

2.Induced Voltage Test of Small Transformer Windings: For small transformers in the power system, the induced voltage test can be carried out through this equipment to check the insulation performance of the windings, including the insulation between turns and layers, so as to avoid insulation breakdown caused by winding defects during operation.

3.Short-time 150Hz Power Source: In some special test scenarios of the power industry, a short-time 150Hz power source is needed. The ZXSBF Third-harmonic Generator can be used as a temporary 150Hz power source to meet the power supply needs of related tests, such as the performance test of special electrical equipment.

五. Conclusion

As a key test equipment for the insulation detection of power transformers, the ZXSBF Third-harmonic Generator has the advantages of reasonable design, excellent performance, simple operation and strong adaptability. Its technical indicators fully meet the requirements of the frequency-multiplied induced over-voltage withstand test in the power industry, and it can effectively evaluate the dielectric strength of transformers and ensure the safe and stable operation of the power grid. For technical personnel engaged in power equipment detection, mastering the working principle, technical indicators and application methods of the ZXSBF Third-harmonic Generator is of great significance for improving the accuracy and efficiency of insulation detection work. In the future, with the continuous development of the power industry, the ZXSBF Third-harmonic Generator will play a more important role in the insulation detection of high-voltage equipment, providing strong technical support for the safe and stable operation of the power grid.
     GDZX is a manufacturer of power detection equipment, offering a diverse range of products with comprehensive models and providing professional technical support. Contact us at +86-27-6552607 or +86-17396104357.Website: http://en.gdzxdl.com/