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Other Structural Improvements And Trends
- Nov 07, 2017 -

 Traditional distribution transformers are used in the 10kV system of neutral point insulation, so the winding of the connection group are selected Yyn0, so that when installed in the high-pressure side switch (including non-excitation tap-changer and on-load tap-off Switches) are located on the mid-point side, so that the switch structure is simple and easy to manufacture. With the increase of non-linear load, the structure of the core of the coil is selected, and the winding junction group is also transitioning to the Dyn11.

Due to the 10kV system of neutral point insulation, the overvoltage multiplier is high, and the 10kV cable distribution system with a small resistance grounding at the mid-point of development in China is also used. The over-voltage ratio decreases and the short-circuit current is limited by the small resistance. In the 10kV midpoint by a small resistance to ground, the winding junction group can be used Ynyn0. This is the development trend of the linkage group.

From the overall structure, the first is the use of tube cooling device, the tank has a storage tank, the transformer oil in the tank and the outside air is Unicom, so the transformer oil to be regularly tested, there is maintenance workload. At present, most manufacturers have transitioned to the use of inflatable heat sink, or corrugated tank structure has been canceled conservator, is a fully enclosed fuel tank structure. In this way, the transformer oil is not in contact with the outside air, the temperature changes make the oil volume change by corrugated expansion and contraction compensation, or by expanding the radiator compensation, distribution transformers can be maintenance-free. Users are welcome to fully sealed structure distribution transformers, so including amorphous iron core distribution transformers, including the development of all-sealed structure.

In the past, distribution transformers were installed on the poles of the platform, far away from the user, it does not assess the impact of noise on the environment. At present, with the increase of electricity consumption, the installation location of distribution transformers is closer to residential areas, and noise has also become one of the items for assessment. Therefore, distribution transformers in addition to meet the low loss, but also to meet the low noise requirements, it is taken in the distribution transformer noise reduction structure and process measures. Some people worry that amorphous iron core can have lower noise. In the same magnetic density, the amorphous magnetostriction is larger than the silicon steel sheet, but the work of amorphous iron core is relatively low, magnetic flux density in different work, the amorphous core is not large, but also can be achieved Low noise requirements.

The traditional distribution transformer is installed outside the transformer by the switch, fuse protection, the newly developed modular transformer (ie, base transformer, or American box transformer) has the load switch, fuse installed in the tank. The transformer can also be used in the ring network power supply system, low-voltage side can be divided into several ways to send electricity, and can be installed protection and metering devices. In this way, low-voltage distribution lines can be shorter, reducing line losses even further. When China's urban and rural power grids for cable distribution network transformation, the box change structure is the best. In addition, due to the current high price of amorphous alloy distribution transformers, the promotion of the use of more difficult, in the future, with the expansion of production scale, the introduction of the promotion of production technology and production increases, the price drop is a foregone conclusion, such Transformers will also have a wide range of promotional value and energy saving potential.