An electrical transformer substation comprises a whole set of devices (conductors, measuring and control apparatus and electric machines) dedicated to transforming the voltage supplied by the MV distribution grid (15kV or 20kV), into voltage values suitable for supplying low voltage lines with power (400V - 690V). This comprehensive ABB technical paper explains the theory, and provides short circuit calculation examples:
In terms of calculation of short-circuit currents, this paper covers the data necessary for the calculation, plus calculation of the short-circuit current, motor contribution and peak current value.
In terms of MV/LV transformer substations, this very useful paper also includes detailed information on the following: Choice of protection and control devices, the main electrical parameters of the protection and control devices, criteria for circuit-breaker choice, coordination between circuit-breakers and switch-disconnectors, and coordination between automatic circuit breakers-residual current devices (RCDs). It additionally provides studies of an MV/LV network, calculation of the transformer inrush current, example of calculation of the short-circuit current, and much, much more besides.
To see the full and extensive PDF document, which is highly detailed and very comprehensive, please click on the download button below (661kB file size). Alternatively, go to http://search.abb.com/library/Download.aspx?DocumentID=1SDC007101G0202&LanguageCode=en&DocumentPartId=&Action=Launch&IncludeExternalPublicLimited=True