Analysis and Countermeasures of the operation acci

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Analysis of operation accident of oil immersed current transformer and Its Countermeasures

at noon on October 1, 1996, the 220kV independent CTA phase of 220kV Yuelong substation #1 of Ningbo Electric Power Bureau had an accident, and the equipment was put into operation for less than 24 hours. Although the commissioning test was qualified, this explosion was purely a quality problem of the manufacturer's manufacturing process, which just showed that the product quality problem could not be said to be absolutely reliable if the test was qualified

oil immersed current transformer is one of the important equipment in the substation, and it is used for protection, measurement and control. Although it is a small power equipment, it does not have arc problems like circuit breakers, nor does it transmit strong power like transformers. Therefore, it is not valued by people, especially the personnel on duty are very easy to ignore it in equipment inspection. However, due to the large amount of use of transformers, due to the design Accidents caused by structure and other reasons continue to occur, endangering the safe power supply of electricity. The explosion accident of transformer not only damages the adjacent equipment, but also causes personal casualties. Therefore, people should pay great attention to it

2 accident causes of current transformer

2.1 classification of current transformer accidents

accidents of current transformer can be divided into two categories according to the nature of the accident. Even if the operation is suddenly interrupted, such as the accident of explosion or imminent explosion and forced to stop operation immediately, such as extremely high ethyne, serious oil leakage, etc., it is called a serious accident. If the operation can be stopped according to the plan, And the accident that the product can repair is called a non serious accident

2.2 intuitive cause of current transformer accident

four explosion accidents are estimated by uniform dispersion: intuitive cause of

a) penetration at the iron clip b) penetration at the bottom C) ponding in the oil tank d) penetration at R

2.3 fault cause analysis of current transformer

product failure is divided into two parts: internal factors of products and installation and operation of products, and internal factors are divided into design technology, process and inspection means and quality control. The design technology is divided into two parts: sealing structure and main insulation

the sealing structure is: (1) the sealing method is not 5 Environmentally friendly and environmentally friendly materials have reasonable technology, such as open type and diaphragm type; (2) The sealing structure is unreasonable. For example, the sealing surface is uneven, and the compression of the rubber pad is not controlled; (3) The sealing material is poor, such as poor low temperature characteristics and permanent deformation of the spring

the main insulation reasons are divided into: (1) the rigidity of the primary conductor is poor. For example, the copper flat wire is too heavy and easy to deform after 18 months of operation; (2) The shape of primary winding is unreasonable, such as partial damage to insulation during leg splicing; (3) The structure of the primary support is unreasonable, such as insulation deformation; (4) The mechanical fixation is unfavorable, such as the insulation is damaged during electric power transportation; (5) The electric field is locally concentrated, and the electric strength is too high; (6) The technical requirements of drawings are unfavorable

reasons for process and inspection means: (1) improper insulation wrapping equipment and process, such as loose inside and tight outside, uneven overlapping; (2) Poor vacuum drying of the body, such as frying process; (3) Improper vacuum oil immersion equipment and process, such as local amplification; (4) Improper sealing inspection means, such as low oil pressure test; (5) There is no high-pressure test means such as partial discharge test and oil chromatography; (6) The margin of type test is insufficient or the reliability test items are few

quality control reasons: 1) poor acceptance of raw materials; 2) The process control is not strict

product installation and operation: 1) no acceptance test; 2) Poor reset after inspection and disassembly; 3) Poor grounding or wrong wiring; 4) The overvoltage protection is inappropriate or the pollution exceeds the specified value of the product; 5) There is no regular visual inspection and electrical inspection; 6) The operation inspection method is incorrect

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