Comparative analysis of 35/10 kV/kV high voltage substation reconstruction alternatives

In power system planning it is very often necessary to make a decision based on evaluating different project alternatives. When dealing with the problem of high voltage substation reconstructions where part of the substation equipment is old and in bad shape, the question, which arises, is whether it is better to make a partial reconstruction of a substation, or to make total reconstruction, completely with all protection, station and communication computer and all signal cables. The tradeoff is between the amount of investment and the upgraded value of the substation in the long run, assuming the same relative value of substation availability for all analyzed alternatives. The paper presents some details of the five different reconstruction scenarios (case studies) with the accompanying analysis of the actuated cost.