Analysis of Technical Difficulties in High-Voltage Testing of Power Transformers





Abstract

To further ensure the safety and reliability of power supply, it is crucial to conduct electrical high-voltage tests on power transformers. In this regard, after studying the main literature and related research materials on electrical high-voltage tests of power transformers, the author briefly discusses the test conditions required for such tests and analyzes the corresponding technical key points. ...

 Preliminary Preparations

As is well known, conducting electrical high-voltage tests on power transformers involves certain risks. Therefore, staff must make thorough preliminary preparations and adopt reasonable measures to prevent accidents, ensuring the safety of test personnel and obtaining reliable test results.

First, relevant data and information should be prepared. For example, staff can prepare data and achievement literature from previous high-voltage tests, as well as documents containing issues and suggestions from pre-tests.

Second, staff should conduct safety inspections on the transformer equipment's own safety conditions and technical issues in advance, so as to effectively improve the consistency between data and test fitting.

Third, prepare high-quality power supply equipment. From previous high-voltage tests, it is known that the power supply equipment used in tests is of large capacity. Therefore, staff should select appropriate power supply equipment according to test conditions, while ensuring that the air switch can meet the test requirements.

Additionally, since the secondary current of large-capacity power supply equipment is relatively high, the cross-section of the low-voltage side wires should be reasonably set to prevent excessive heating during application.

Fourth, use measuring instruments to check the temperature and humidity of the laboratory. If both exceed the reasonable range for testing, test personnel are prohibited from conducting electrical high-voltage tests.

Usually, since different equipment have different temperature requirements during testing, staff are required to read data based on the oil temperature around the windings.

Finally, analyze the nature of the high-voltage test. If it is a withstand voltage test, staff should comprehensively analyze the capacity of the step-up transformer based on the actual capacity of the transformer equipment being tested, and control it reasonably.

It should be specifically pointed out that if the voltage value is too small, during the voltage application operation, due to the influence of current leakage, the voltage value will continuously decrease, thereby affecting the accuracy of the final test data.

Key Points of the Test

First, during the wiring process, staff should strictly follow the pre-established execution plan and not handle wiring according to personal preferences.

Second, in the early stage of high-voltage testing, staff should conduct detailed analysis of the wiring composed of each part, and supervise the fairness and comprehensiveness of the inspection work, so as to ensure the contact quality of the wiring to a certain extent.

Additionally, during the high-voltage test, staff should also improve the reliability of the grounding of the metal shell of the test instrument as much as possible. Then, if a voltage regulator device is needed during the high-voltage test, staff should pay attention to whether it is in the "zero" state.

When using the voltage regulator device, staff should rotate the handle part evenly to increase the voltage slowly, while recording the operation and changes in instrument readings.

Finally, after the high-voltage test is completed, staff must adjust the voltage value of the voltage regulator device back to the initial "zero" state and cut off the power supply.

Data Analysis

As is well known, there are many types of electrical high-voltage tests for power transformers, and different tests yield different data information. Therefore, when staff carefully analyze test data, they must ensure the reliability and scientific nature of the analysis.

If during the high-voltage test, the transformer equipment emits a "beeping" sound, staff need to analyze the characteristics of the sound.

For example, when slowly increasing the voltage to the test standard, if a "beeping" sound occurs but the instrument indicator does not change, staff can reduce the voltage value to ensure the orderly progress of the test.