Problems needing attention in insulation protection of Substation

- Mar 23, 2019-

The application of thermal shrinkable materials in comprehensive insulation protection of substations can reduce accidents and improve the reliability of power supply system, which is of great significance to the safe operation of power system. So what problems should be paid attention to when substation implements insulation protection?

Substation insulation protection precautions:

(1) Choose different thermal shrinkage materials according to different substation facilities.

For bare bus, the insulated bushing (MPG) of bus can be selected, and the composite insulated heat shrinkable tape (FJRD) can be used for winding. The former must disassemble the mother row, which is difficult to construct and takes a long time, but beautiful and glossy after treatment; the latter need not disassemble the mother row, and the construction is easier and the time is shorter. Users can choose according to the actual situation. If the new substation is not put into operation and time is abundant, MPG mode can be adopted, while FJRD mode can be considered for the old substation with limited blackout time.

Insulated joint protection box can be used at bus bar joints or bushing joints, such as through-wall bushing and main transformer low-voltage side bushing. Because the joint joint joint often needs to be unloaded, the insulating protective box can be flexibly opened and closed to facilitate maintenance, do not use insulating sleeve or thermal shrinkage band fixed to death. Users should contact the manufacturer beforehand and prefabricate various shapes of insulation protection joint boxes (I, J, T, etc.) according to the site conditions.

FJRD should be used to insulate charged bodies with special appearance and not often disassembled.

(2) On heat treatment

Insulating bushing or thermal shrinkage tape can shrink on the surface of charged body only by heating treatment. Therefore, heating treatment technology is not only related to the life of materials, but also related to safety. The following points should be paid attention to in heating treatment: 1. The appearance should be smooth and uniform after heating, and the wall thickness should not exceed 3 mm after contraction. (2) Heat shrinkage should be guaranteed to shrink in place, no air gap remains in the middle, or it will lead to fever affecting life, especially in the corner, which should be carefully handled to ensure that it is in place. (3) It is very important to treat the heat shrinkable sleeve (1 m long) or the joint of the heat shrinkable belt. The heating time at the joint must be long enough to ensure its heat shrinkage and smooth transition, so as to ensure that the electrical performance of the front and back sections and the joint is the same.

(3) Live Experience Potential of Remaining Mother Volume

The bus bar and the bus bar before and after the switch must be set aside for checking grounding in order to be used for checking grounding in overhaul. ABC three-phase potentiometric potential must be selected according to the actual site. Three-phase positions of A, B and C should be triangular, not a zigzag, to increase the distance of three-phase bare charged body to prevent short circuit of small animals; in addition, as far as possible away from supporting insulators, in order to prevent flashover of charged body to porcelain bottles, see Fig. 1.

(4) About the Climbing Distance Increaser

When adding anti-fouling and climbing skirt to supporting porcelain bottles, strict and meticulous cleaning treatment must be carried out first, and then the climbing distance increaser should be installed. As shown in Figure 2, when 502 is glued to place A, the treatment of joints will directly affect the use effect. Ideally, the joint should be smooth and smooth without bumps. If the joint is not smooth, long-term wind and rain shower will leave dust around it, which not only does not increase the climbing distance, but also increases the hidden danger of pollution flashover. Therefore, strict control must be taken during construction.

(5) Other matters needing attention

For transformer substation facilities with thermal shrinkage insulation protection, all exposed parts of electrified bodies should be protected by thermal shrinkage sleeve or thermal shrinkage belt, and no dead angle should be left. If the low voltage bushing of the main transformer has not been insulated before, recently the special-shaped protective box is used for insulation protection, which effectively prevents short-circuit of the main transformer caused by small animals. In addition, for insulation protection of dismantled bus bars, after restoring the original wiring mode, it is necessary to ensure that the connection is firmly fixed, in order to prevent the joint from heating due to the loose bolts.

Of course, we can not abide by the rules, in addition to the above need to pay attention to the specific situation of substation insulation protection analysis and treatment.