According to the regulations of "Code for fire protection design of buildings" (GB 50016-2014)

an automatic fire extinguishing system should be installed for a separate oil-immersed transformer with a capacity of 125 MV·A and above. Some of the old type transformers with 125 MVA and above are not equipped the hole with oil evacuation and nitrogen injection extinguishing device

and there are no holes prepared for oil evacuation and nitrogen injection pipes in advance. In order to solve the problems of the old oil-immersed transformer without interface connected to install the oil evacuation and nitrogen injection extinguishing device

an innovative solution of using transformer manhole

oil discharge valve and sampling valve as connection interface is proposed. Compared with the method of opening new holes in transformers

the proposed method has the advantages of simplicity

convenience and safet

which can greatly shorten the reconstruction time and save the construction cost.