Whether power transformers required to have magnetic core grounding?

The magnetic core of the transformer is made up of thin plates that are isolated from one another.

These plates give a carrier path to the magnetic field, and because the plates possess an extremely low magnetic resistance, the majority of the magnetic flux is able to flow through the core without experiencing any loss.

In case the insulation in one or more coils fails partially or entirely, a voltage will be induced in the magnetic core.

This voltage will produce a partial discharge, which may lead to the transformer’s complete failure. In that condition the insulation in one (or) more coil fails partially (or) completely, a voltage will be induced in magnetic core.

This for the protection of the equipment, so only have a single point of connection between the core and the ground. In the condition that the cardiac potential rises to high levels as a direct consequence of a failure in isolation, the fault current will find its way from the core to the ground.

There are two different approaches to grounding the magnetic core of transformers, which are as follows:

  • Establishing a connection between the transformer’s grounded structure and its magnetic core.
  • The provision of the transformer with an additional bushing that can be used to connect its core to an additional grounding point.

If the transformer has a large capacity, the main part of the device will be divided into multiple parts. Isolation of the core parts will be provided by cooling tubes.

The core portions will be connected to each other and, eventually, they will be connected to a single grounding point. This will be accomplished by implementing jumpers, which will connect the core sections.

A capacitive coupling develops between the coils & the core of the transformer whenever the device is subjected to an electrical voltage. The ground point in the core is where the discharge is directed so that it can take place.

Because of the potential for numerous currents to flow through several grounding points, the core of the transformer is often only grounded at one point in the system.