At the scene of the high voltage transformer partial discharge test research

With the rapid development of power industry in our country, the national power grid construction process has been accelerated, and the progress of science and technology to electric power equipment also in constant innovation.Transformer equipment has a pivotal role in transformer substation, transformer equipment quality directly affects the normal operation of the transformer substation effect, especially the impact of high voltage transformer is more serious.Based on this, in this paper, the anomaly at the scene of the high voltage transformer partial discharge test is analyzed and discussed. (transformer aluminum strip)

 Transformer equipment quality matters, far-reaching, therefore, the partial discharge test of transformer is very necessary, it can correct detection performance of the transformer and effective response of the transformer design level and production process control level.All high voltage transformer in China, is currently in the factory or partial discharge test must be conducted before put into use, to ensure the transformer quality qualification, to be put into use for transformer normal and safe operation of the power system stability, provide a reliable guarantee.

 (transformer aluminum strip)

An overview, partial discharge test

(1) partial discharge are introduced

    Partial discharge is refers to the electrical equipment in the field greatly under the action of applied voltage, discharge occur so that the insulation of the electrical equipment area, but formed in the discharge area of the electrical equipment without discharge channel.Partial discharge phenomenon occurs mainly in high voltage electrical equipment, for example, is easy to occur in the high voltage transformer partial discharge phenomenon, partial discharge phenomena easily damages to the high voltage electrical equipment insulation parts.Therefore, in the high voltage transformer factory or partial discharge test must be conducted before put into use.The cause of high voltage transformer partial discharge occurs mainly has two points: one is the high voltage transformer itself insulation or other performance indicators unqualified;Secondly, the high voltage transformer material has a problem or there is something wrong with the production process. (transformer aluminum strip)

(2) the dangers of partial discharge

    The harm of partial discharge is mainly the following aspects: one is the partial discharge can cause electrical equipment overheating situation, so as to cause damage to electrical equipment;Second, partial discharge will produce a series of bad phenomena and reaction, such as chemical reactions, electrical pulse, electromagnetic radiation, such as the bad phenomena and reaction to the surrounding environment and cause serious damage to people's life health;3 it is to have a discharge easily led to the breakdown of transformer insulation layer, thus greatly reduce the insulation performance of transformer, eventually leading to the accident.

(3) the significance of partial discharge test

    On-site partial discharge test was carried out on the high voltage transformer can correct detection of transformer insulation performance and other performance indicators, and at the same time also can effectively response should be transformer design level and production process control level.Partial discharge test is an important link of high voltage transformer testing, which has convenient operation, high precision, good flexibility, widely used in transformer testing, therefore, the high voltage transformer partial discharge test has very important significance . (transformer aluminum strip)

Second, at the scene of the high voltage transformer partial discharge test research

    Based on the work demand, the author will combine their own actual situation and practical experience of high voltage transformer on-site partial discharge test abnormal situation analysis.

    On November 8, a high voltage transformer had just finished production assembly factory, carried out in accordance with the requirements of the station high voltage transformer partial discharge test on site.Through experiment found that put power station high voltage transformer in excessive amounts of anomaly.The cause of this abnormal phenomenon appeared mainly has two points: one is the insulation of the transformer in bubbles;Second, the bubbles exist in the transformer oil.Know this, then the next time before the partial discharge test, should carefully check clean-up transformer, through heating test to eliminate air bubbles. (transformer aluminum strip)

    On Nov. 11, after increasing the heat test transformer, stay temperature cooling equipment parts shall be carried out again after partial discharge test, through test results the same as the 3 days ago, so they test that may be the problems of transformer bushing, so the test of transformer bushing and two phase high pressure casing carefully check, found that the presence of gas evolution, therefore, decided to let stand for a period of time for gas fully escape.

    On November 15, the third time for transformer partial discharge test, small found first phase transformer partial discharge, so the test personnel of transformer oil extraction experiment was carried out, the results show that belongs to the normal situation. (transformer aluminum strip)

    On November 22, the first phase of transformer partial discharge test, through the experiment discovered anomalies: when testing at the beginning, it is the first phase of the transformer partial discharge is not very stable, in the first phase of 6 to 10 minutes after the transformer partial discharge gradually stabilized, found that first phase of the transformer partial discharge is still in the scope stipulated in the technical agreement.Then the next November 24 and 26 November, respectively, the first phase of the transformer transformer partial discharge test and sample analysis. (transformer aluminum strip)

    Through the analysis of the results obtained from the above test, that the partial discharge test for many times, transformer insulation falling and deterioration.The causes of abnormal discharge transformer condition, not only is the transformer oil bubble, also may be the transformer insulation performance.In addition, through the analysis of load transfer capacity of the transformer to find out the abnormal discharge in transformer parts correctly.

Three, high voltage transformer partial discharge test of the existing problems and solutions

(1) transformer structure defects and solutions

    Transformer structure defects will be uneven distribution of electric field of dielectric and the partial discharge test, discharge scale very unstable phenomenon.Transformer structure defects in the solution measures are: to transformer partial discharge test before, strict and careful check of the transformer structure, to ensure the rationality of the structure of transformer, and the transformer are induced overvoltage, lightning shock test, after waiting for transformer by the experiment, to partial discharge test. (transformer aluminum strip)

(2) corona discharge effect and the solving measures

    Under the condition of the high voltage corona phenomenon, transformer easily happened under the effect of electric field, the high voltage transformer in some grounding inadequate parts produce abnormal discharge, the discharge of partial discharge test severe impact test results.The solution of the corona discharge effect: to carefully check of high voltage transformer, to ensure the high voltage transformer grounding completely, and shielding of high pressure casing, to prevent the result of the high voltage corona phenomenon. (transformer aluminum strip)

Four, conclusion

    In conclusion, this article from the scene of the partial discharge test overview, high voltage transformer with abnormal discharge test research as well as the problems existing in the high voltage transformer partial discharge test and analyzes and discusses the solution aspect, has very important significance, not only helps to ensure the quality of high voltage transformer, to ensure that the power system normal, also help to promote the sustainable development of our country electric power industry. (transformer aluminum strip)