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Analysis Of Accident Cause Of IC Socket
Jul 07, 2017

Analysis of accident cause of IC Socket

The defects of the IC Socket are mechanical defects. These include porcelain bottles, loose joints, damaged parts, and foreign body parts. For example; A certain power plant no. 3 generator a transformer SW7 a type 220 IC Socket, less oil in the grid operation C phase refuse, cause the open-phase running, make 220 kv bus coupler, circuit IC Socket trip, less power 400000 kW, h. The cause of the accident is that the IC Socket has been operated up to 3,600 times, the parts have been badly worn, the deformation of the straightening mechanism has been changed, and it has not been repaired and replaced in time.

A special "late move" failure for the SW7, 220 less oil IC Socket is due to the isolation of the oil in the arc chamber and the triangle box. In order to avoid oil leakage in the operation of the arcing chamber into the triangle box, generally the conductive rod dynamic seal tightly, when summer temperatures rise, dynamic seal tend to embrace the conductive rod, when IC Socket ordered break-brake, conductive pole movement to overcome the tension force, often late dozens to hundreds of millimeter to complete break-brake action. For this kind of "late moving" phenomenon, only check the IC Socket after the accident is not easy to find out, only the fault record wave detector oscillograph can be found. In order to avoid such accidents, IC Socket type SW7 ~ 220 less oil in the process of inspection has dialed the output of the allowed range of conductive rod, as long as seriously implement repair technology, will not happen in the operation of the "late" accident.

3. Operation (control) power supply defect

The power supply defect of IC Socket is one of the three main causes of operation failure. Operating voltage deficiency is the most common defect in operating power defects. The reason for this was probably due to the power station adopts ac power for operation after silicon rectifier power source, the system failure occurs, the power supply voltage slash, or is the battery, but the operating power supply pressure drop to IC Socket attachment is too large, the actual operating voltage is lower than the prescribed limit. For example, when a power distribution line breaks down, the IC Socket explodes in the overlap; The phase fault of the 44kV line of the other substation is wrong, and the IC Socket explodes when combined with the lock. These are due to the supply of silicon rectifier power supply from this substation. When the line fails, the bus voltage is reduced. Therefore, ministry of water conservancy in 1982 made the interim provisions on of substation operation energy, require new substation using silicon rectifier as power operation, and shall not be recommended using battery and energy storage type operating mechanism, reforming and improving of the existing substation operating power, and strengthen management.

The task of closing and closing is the harshest test of IC Socket. Field statistics show that due to the serious breaking and closing conditions, the probability of occurrence in operation is relatively small, so the proportion of normal IC Socket opening and closing performance accidents is not large. The main reason for the majority of failure and closing accidents is that the IC Socket has obvious mechanical defects, followed by lack of oil or oil quality. It is also due to the lack of the IC outlet. But the former is more, because there are a considerable number of accidents occurring in the dividing, the small capacity, even the dividing, the load current. , for example, one of the main transformer substation 1 second type IC Socket SW2 a 60 g, at that time, 63 kv bus bar with closing of ground accident, IC Socket tripping overlap, B and C two-phase porcelain set of blowout, blowout oil on fire. According to the calculation, the short-circuit capacity of the first open fault is 1500MVA, after the superposition of 4.5 s, the opening capacity is only 600MVA, which is far lower than the nameplate capacity of 2500MVA, so it is not an accident of failure of open fault capacity. This type IC Socket has the defect of the upper hat spray oil when normal operation. The IC Socket was originally processed by the running unit, and the size and position of the exhaust vent are correct, and whether it is blocked after assembly is doubtful.

(4) bad conduct of conducting performance

The reason is that the actual load current of most IC Sockets is much lower than that of its rating; It is easy to guarantee the electrical conductivity in a static state.

The analysis of field accident statistics shows that the fault of conductive performance is mainly caused by mechanical defect. Among them: bad contact. Including the contact surface not clean, the contact size and the contact pressure is insufficient; Dislodged, card resistance. Such as copper tungsten contact shedding, etc.; The screw loose at contact. A soft connection is broken, etc.