The On-site Measurement Research of Converter Transformer Harmonic Losses Based on Harmonic Power Source

HVDC converter transformer is a highly nonlinear transmission of harmonic source, which produces large amounts of harmonic current during the operation. The harmonic losses caused by harmonic current share more than half of converter stations’ losses, and affect temperature rise and load capacity of converter transformer. For safe and economic operation of the converter transformer, accurately measuring the converter transformer’s harmonic losses has a great significance. This paper propose a method of converter transformer measurement based on harmonic power source by applying the 1/2 rated harmonic current on the AC side of converter transformer. According to comparison of calculation and test result, this paper finds that the calculation method recommended by IEC 61378.2 and GB/T 18494.2 can’t give out the accurate harmonic losses of converter transformer. With the test data, this paper gets the harmonic losses’ frequency characteristic of converter transformer and the harmonic loss coefficient $K_{r,h}$.