Methodology and algorithm for ranking substation design alternatives

The design of an electric power substation is a very complex process, which greatly depends of customer functional requirements and existing boundary conditions. Many different solutions are possible to fulfill the substation functional requirements within these conditions. The problem is to select one of these possible solutions that will be the closest to fulfilling the customer requirements. The paper presents a methodology and algorithm implemented in a tool for evaluation and comparison of different substation alternatives. A systematic procedure using multi-objective value hierarchy is applied to make the final decision. Three major objectives used for the decision making process include life cycle cost, substation performance, environmental factors. The methodology includes customer preferences (weights) as well as an estimation of the values of all the attributes for every one of the substation alternatives. The final ranking solution is shown in graphical and numerical form. By using a combination of "hard"(presented usually in dollars) and "soft"(subjective and very difficult to express in numbers) attributes, the presented methodology allows ranking of the feasible substation alternatives. Combined with the power of other tools for substation functional requirements, reliability and economical estimation this methodology allows the customer and the vendor to make the right decision.