Method for evaluating insulation aging state of stator bar based on space charge method

Abstract

The invention relates to a method for evaluating the insulation aging state of a stator bar based on a space charge method. When a simulated unit works, a stator bar is affected by electric aging, heat aging and mechanical aging. A simulated iron core (1) and a vibration platform (2) form an integrated aging testing device. In an electric aging test, the bar is placed in the simulated iron core tocarry out horizontal vibration, wherein the aging temperature is between 80 DEG C and 90 DEG C. A reference bar (3) carries out electric aging testing at voltages of 1.6UN, 2.0UN, 2.5UN, and 3.0UN, wherein the UN expresses the rated voltage of the wire rod; and on the basis of a relationship map between the voltage and the breakdown time, the service life of the reference bar is calculated. A testing bar (4) carries out electric aging testing at the voltage of 1.0UN; and space charge testing and breakdown testing are carried out at 0h, 500h, 1000h, 1500h, 2000h, 2500h. According to a functionrelationship of total space charge amounts, space charge threshold field strengths and residual breakdown voltages of different aging time, the residual service life of the test bar is evaluated.

Description

Technical field: [0001] The invention relates to a method for detecting and evaluating the insulation aging state of a stator bar by using a space charge method. Background technique: [0002] Generators are one of the most important electrical equipment in power plants, and their operating status directly determines the safe and stable operation of the power grid. Generator stator bars suffer from aging degradation due to the combined effects of thermal, electrical, mechanical and environmental factors for a long time. Studies have shown that the insulation state of the stator coil directly determines the operating state of the generator. Therefore, accurate evaluation of the insulation state of the stator coil is of great significance for formulating a reasonable maintenance plan and improving the operating reliability of the generator. At present, the detection methods of generator stator coil insulation mainly include conventional test methods such as insulation resista...

AI Technical Summary

Problems solved by technology

These methods have the following disadvantages: the test uses AC high voltage, which will cause cumulative damage to the insulation; the test uses power frequency or DC voltage, and the insulation information obtained is single, and it is susceptible to field interference, and the test results are scattered, making it difficult to accurately evaluate the generator. state of insulation

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