Proposed standards for frequency conversion factors of transformer performance parameters

This paper presents the development of appropriate frequency conversion factors for performance parameters of transformers. These factors are needed in order to allow manufacturers to convert measured values from 60 Hz to 50 Hz and vice versa. Conversion factors are necessary when equipment at a manufacturer's test facility allows direct measurement at one frequency and not the other. These factors are developed in this paper for no load loss, exciting current, load loss, and noise level using both analytical and actual tested data. Measured data, provided by several manufacturers, was used to confirm the theoretical results. This paper will be used as a basis for proposing standard frequency conversion factors in the IEEE/ANSI (Ref. 1) and IEC test standards for power and distribution transformers. Such a standard will make it possible for manufacturers to use the same frequency conversion factors and hence have a more uniform accuracy of the reported test data at both 50 and 60Hz.