SRC-239

ENA Engineering Recommendation G5, Issue 5, 2020 (EREC G5/5): harmonic voltage distortion and the connection of harmonic sources and/or resonant plant to transmission systems and distribution networks in the United Kingdom.

Published claims resting on this source

• CLM-0787 The UK harmonic planning levels for networks above 230 kV set total waveform distortion at 3 per cent, with the largest single-harmonic level being 2 per cent at the fifth and seventh harmonics. These are levels for the network as a whole, and each connection gets only a share of them. The document is a recommendation, and it is careful to say which of its words are mandatory.
• CLM-0788 If the ground station has several hundred converter units and their diversity is declared, the harmonics standard lets their high-frequency distortion partly cancel while their low-frequency distortion adds up directly, so the hardest limits to meet are on the low-order harmonics below the fifth and not on the high-frequency switching harmonics that inverter designers usually worry about. Without that declaration the standard requires all their distortion to be added up directly, and the low-order harmonics are no longer singled out.

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