Compensation of the first natural frequency of inductive medium voltage transformers

摘要

Up till now inductive voltage transformers are only suitable for measuring harmonics if high measurement errors are acceptable. However, as monitoring frequency harmonics becomes more important, the design of inductive voltage transformers needs to be changed in a way to increase its frequency range. The poles and zero points of the frequency response of voltage transformers can be compensated by using different methods. One possibility is to connect an external capacitance to the half winding in order to compensate the first resonance or to connect it to the quarter of the winding in order to compensate the second natural frequency. Another alternative is to change the winding itself for compensating resonance frequencies without using any capacitances. Finally, it is explained how to minimize the transformation error at frequencies up to 9 kHz.