Design Criteria and Considerations for Building a Primary Substation for an Industrial Plant

Parameters that must be considered in the design of a large substation are described based on experience with a 40 MVA outdoor primary substation for an industrial plant including the installation of the primary transformation from the 138 kV utility system. Selections of equipments such as bus sizes, transformer ratings, circuit breaker type, and ratings necessary to achieve the desired degree of continuity of service and coordination are discussed. In addition, a description of the protective relaying circuitry for both primary and desired backup protection is included.