Tensorial Analysis of Integrated Transmission Systems; Part II. Off-Nominal Turn Ratios [includes discussion]

When the turn-ratios of transformers differ from the ratios of nominal values assigned to the different voltage levels of transmission, the a-c network analyzer representation of a transmission system requires autotransformers. The currents flowing in the latter form quite a large percentage of the total current entering the network and consequently the auto-transformer currents cannot be ignored. Their resultant is subdivided into a no-load current and a turn-ratio current. The no-load current is neglected and the turn-ratio current is eliminated from view by a transformation. Afterward the steps given in the first part of this serial for setting up the loss equations L = MP are retraced here. A change occurs only in the calculation of C23. A numerical example appears in reference 1.