1. Power transformer anti-leakage measures as follows:
1.1 The connection flange on the tank cover and tank walls all use impermeable screw holes with seal grooves, the sealed surface is machining structure. Between flanges are rigid connection that avoid flange screw holes and sealed surface oil leakage.

1.2 The structure of tank is bell prover and should be sealed and adopted vacuum oiling.

1.3 All flanges all use internal and external welding process. The pipe joints are inputted tank walls 10mm that can reduce the oil leakage due to the poor welding.

2. Power transformer technical measure for reducing the noise
2.1 Rational to select the core that rated flux density below 1.72T. It prevent silicon steel over magnetization, also can effectively reduce the noise that produce by vibration of silicon steel.

2.2 Improving the core structure, using multilevel juncture. When the core lamination, we must strict control the geometry size, avoid resonance.

2.3 Approproately enlarging the coil brace and cushion block’s size that make the coil structure firmer and reduce vibration. This way can reduce the noise spread.

3. Measures to improve the ability of resistance to sudden short circuit
Transformer short circuit is a dynamic process, research shows that only consider the first peak current static calculation, is not fully reflect the state of transformer, sometimes even dangerous, in recent years, our company cooperate with domestic colleges and universities, and it is precisely from the key place of the transformer coil short-circuit strength further research work.

Using constant voltage dry coil and whole assembly process, to ensure the axial height of the coil, if need regulator to rectification order, strict control the axial height of the ampere turns partition, in order to meet the design requirements. Adopting reasonable lead clamping structure to guarantee that has enough mechanical strength. Design the appropriate coil end insulation structure, which can guarantee the coil axial compression.

Improving core cross-section shape, guaranteeing the core roundness, radial support internal coil. Core coordinated with inner coil allowance that without clearance, which ensure the coil and core magnetic center. In that way, it can effectively resist the transformer short-circuit inward radial electric power.

Active part and tank had been reliable positioning, make the active part can withstand the impact of the various transport conditions for 3 g impact test without displacement. The transformer manufactured by us has a strong ability to resist sudden short circuit. All samples are one-time through the national transformer quality supervision and inspection center of short-circuit withstand test, at the same time products withstand the test of the runtime fault.

Through a large number of experimental and theoretical study, in terms of transformer short-circuit strength determines the new calculation and design method, the original fixed predominantly static calculation method and improvement, the calculation method of the improved now widely used in the design of the transformer in our factory.

4. Low stray loss, some technical measures to prevent the local overheating
Through calculation software, reasonable layout distribution of ampere turns winding along the height direction, make all the winding magnetic potential distribution should minimize the transverse leakage magnetic field.

The material used for opening position of cover for large current bushing is no magnetic materials. High voltage bushing increases used no magnetic materials, in order to ensure various metal parts, reliable contact potential is not suspended, in addition to the interface is not painted, and ground wire to ensure reliable contact each other. The low voltage bushing on the cover be fixed on the no magnetic material plate.

In the large capacity transformer, along the tank wall to place the magnetic shunt, make the most of the magnetic flux leakage flow to the tank wall into the magnetic shunt, which can reduce the loss of tank wall.

Choose small cross section size wire (especially in the size of the vertical direction of the leakage magnetic field), using the parallel wire or transposition wire.

To slotting in the middle of pulling plate, minimum level core column, and etc.

Large current lead arrangement must meet the following requirements: copper bar must be used narrow in the face of the walls, in order to reduce the leakage flux lead, the distance between copper bars should be as narrow as possible, adjacent copper bar current should be compensated each other. The pressure plate is made of high strength laminated board.