Experimental Investigation of the Harmonic Distortion at Points of Common Coupling of Urban Substations in Ukraine

Purpose of work is experimental study of nonsinusoidal current and voltage transformer substation loads of urban areas in Ukraine, research of harmonic structure of group loads and their compliance with international standards. Methods. The monitoring was held for a week at the input low voltage power transformer at urban transformer substation using RESURS-UF2M device. Results. Total harmonic distortion THD of voltage on tires 0.4 kV transformer substation does not exceed 8%. The level of individual harmonic voltage does not exceed 5%. Overnight TDD current value at input 0.4 kV transformers exceed twice the limit values according to the standard IEEE 519–2014 in phase B daily 4.4 percentile and slightly in phase C - 0.1 percentile. The results of the weekly monitoring are based on 10-minute averaged values, TDD current of all three phases exceeded the limit value (5%) in phase A - 38.9 percentile, phase B - 51.1 and phase C - 6.9. So there are violations of the standard requirements of weekly 95th percentile within 5% in all phases. In terms of individual harmonics during the week exceeding 95 percentile permissible values were recorded for 3 and 5 harmonic phases A and B, the value of which amounts to 7% of the maximum demand current at the point of common coupling (PCC). Exceeding the limit values was recorded, more than 30% of the time monitoring. This is does not correspond to standard IEEE 519–2014. Practical value. To control the level of higher harmonics in the PCC it is necessary to use the standard IEEE 519–2014. At locality substations with high harmonic currents, it is advisable to install HMTs transformers and harmonic active filters.