Strategy for upgrading the transformer substations taking into account the structure of the medium-voltage network

The authors using the example of transformer substations, how the total amount of necessary upgrading expenditure for selected equipment can be quantified. The initial situation is analyzed by means of a representative random sample. Taking into account further influential factors, a hierarchy for clearing the enormous amount of work to be done can be deduced from the upgrading strategy. The results obtained allow factors to be determined which are of importance in the context of upgrading expenditure. Extension and modification of the medium-voltage network to form open-operation ring systems allow primarily the use of three-panel gas-insulated medium-voltage switchgear in both renovation and reconstruction of transformer substations. Selected fault-susceptible equipment, such as the solid-insulation high-voltage distribution boards, will be replaced. With the results obtained, the procedure is a useful tool for the preparation of business-strategic decisions