What is the scope of transformer gas protection?

The scope of transformer gas protection includes:

1) Multi -phase short circuit inside the transformer.

2) Short -circuit, winding and iron core or shell short circuit of the transformer

3) Iron core failure of the transformer.

4) Under the oil surface or oil leakage of the transformer.

5) Poor contact between the connection switch or the welding of the wires is not firm.

What is the scope of transformer gas protection?-SPL- power transformer, distribution transformer, oil immersed transformer, dry type transformer, cast coil transformer, ground mounted transformer, resin insulated transformer, oil cooled transformer, substation transformer, switchgear