Harmonic performance requirements of an HVDC connection; network owner perspective

In the UK, National Grid Electricity Transmission (NGET) is required by its Transmission Licence to apply and comply with the Grid Code. The Grid Code requires that for Electromagnetic Compatibility Levels for harmonic voltage distortion, Engineering Recommendation G5/4-1 shall be applied. To ensure compliance with this requirement, development schemes relating to new connections need to be assessed for their expected impact on the harmonic distortion levels at the planning stage. This paper describes the methodology and application of a Stage 3 assessment as required by ER G5/4-1 to a high voltage direct current (HVDC) connection scheme to define its harmonic performance requirements. The final requirements as given to the connectee are also presented.