How to connect the shielding layer of the transformer

The shielding layer of the transformer is a very important protective layer in the power system. It can effectively prevent electromagnetic radiation from interfering with the surrounding environment and also protect the transformer. The internal electrical equipment is protected from the influence of external field strength, thereby improving the reliability and stability of the system. So, how should the shielding layer of the transformer be wired? Below we will introduce the relevant knowledge in detail.

First of all, we need to understand what a transformer shield is. The shielding layer of the transformer is a shell made of metal material, usually cylindrical or rectangular, and is usually divided into two parts: an inner shielding layer and an outer shielding layer. Its main function is to shield the magnetic field and electric field of the transformer inside, prevent them from interfering with the surrounding environment, and protect the electrical equipment inside the transformer from the influence of external field strength. During the operation of the transformer, the shielding layer must be well grounded to ensure safe operation.

Next, let’s introduce the specific method of wiring the shield layer of the transformer. First, a suitable grounding point should be selected. Generally speaking, the shielding layer of the transformer should be the same as the grounding point of the transformer body. This can ensure that the grounding potential of the entire system is the same and avoid problems caused by different grounding potentials. When selecting a grounding point, you also need to consider the size of the grounding resistance. The grounding resistance is usually required to be less than 4Ω to ensure a good grounding effect.

Next, we need to choose the appropriate wiring method based on the specifications of the transformer and the type of shielding layer. For ordinary dry-type transformers, the inner and outer shielding layers are usually grounded to each other to ensure good shielding effect. When wiring, you can use a special shielding ground wire to connect the inner and outer shielding layers to ensure connectivity between each other. The advantage of this wiring method is that it is relatively simple to connect, but it should be noted that the inner and outer shielding layers cannot short-circuit each other, otherwise it will affect the normal operation of the transformer.

For shielding layers made of special materials, such as aluminum alloy shielding layers, the wiring method generally adopts channel grounding or angle steel grounding. In channel grounding, a channel is usually opened at the bottom and head of the shielding layer, and then a special shielding layer grounding wire is used to connect the two. The advantage of this wiring method is that the grounding effect is good, but it requires special processing technology and tools, and the operation is more troublesome. In angle steel grounding, several small holes are often made at the bottom of the shielding layer, and then angle steel is used to fix the shielding layer on the foundation and connect the angle steel to the grounding grid. The advantage of this wiring method is that it is simple and easy to implement, but it should be noted that the size and quantity of the angle steel should correspond to the size of the shielding layer to ensure that the wiring is firm and stable.

In general, the shielding layer wiring methods of different types of transformers are different and need to be selected according to the specific situation. When wiring, you should strictly follow relevant specifications and standards to ensure good grounding effect and avoid accidents such as electrical fires. At the same time, the shielding layer of the transformer must be inspected and maintained regularly to ensure its operating effect and safety performance.