The causes of winding failure damage are extremely complex, and the various causes affect each other. The most common causes of failure damage can be summarized as follows:
(1) Modern large-scale transformers generally use tangled or tangled winding structure. If the connection between the wire and the inter-segment tangled wire joint is poorly contacted, it will cause local overheating fault, and make the gall insulation suffer thermal damage, resulting in inter-block or inter-segment short circuit fault.
(2) When the transformer is affected by external short circuit, especially when the outlet short circuit impact near the area, one or more conductors of a certain section of the winding may be misaligned, even if the dislocation does not necessarily occur immediately, but the vibration generated by the electromagnetic force during the operation of the transformer loosens the core bolt, or when the transformer repeatedly suffers from serious electromagnetic impact, the insulation between the adjacent dislocation wire boxes is worn and may also lead to breakdown, resulting in winding misalignment, and then denaturation damage.
(3) When the quality of the winding wire is poor, it leads to direct contact between adjacent boxes, resulting in a short circuit between the blocks. This damage is more common in high-voltage windings.
(4) The transformer winding is an integral structure composed of insulating pads separating the line segments, if the margin of the axial compression force of the large transformer winding is insufficient, the elastic effect of the insulating pad will be weakened, and the integrity of the winding will be seriously affected. In this case, during the load of the transformer, the vibration generated by the electromagnetic force may misalign some of the wires of the winding, and a short circuit between the windings may occur.
(5) When the transformer is subjected to a strong impact of electrical stress or magnetic stress, if the transformer suffers from a certain degree of strong load fluctuation, the winding is very easy to be damaged.
(6) When the transformer continues to be overloaded, the overall temperature of the transformer will be too high, which will accelerate the deterioration and brittleness of the insulation, which may eventually lead to cracking and falling off of the insulation, resulting in a short circuit between the boxes and damage to the insulation resistance.
(7) When the transformer needs to change the voltage and carry out tap switching, if the tap instruction of the external operating mechanism is inconsistent with the internal wiring, resulting in the dislocation of the tap, or the tap adjustment is not in place during operation, it will produce a short circuit of the winding to the ground or a large resistance short circuit fault in the winding tap area, resulting in damage between the winding distances.
(8) Water or moisture infiltrates due to sand hole in the upper component or manifold pipe, poor sealing of oil conservator or casing, failure of silica gel in the dehydrating absorber, poor sealing of rape, etc., if the moisture invades into the winding insulation but is not treated in time, it will occur and cause damage to the transformer.
(9) Due to the weak links in the insulation structure and the existence of bubbles in the insulation system and the dampness of the operating insulation, the dendritic discharge fault of the screen may occur, which will eventually lead to a short circuit between the winding boxes and local damage to some line segments.
Kingrun instrument company was established in 1999, located in Electric Valley in Baoding city, our main production is measuring instrument for power transformer, distribution transformer and electric power industry, such as transformer turn ratio tester, transformer winding resistance tester, transformer oil breakdown voltage(BDV) tester, transformer capacity tester, transformer neutral grounding resistor etc.
