Multipoint Synchronized Recordings in Offshore Wind Farms With Continuous Measurement Power Quality Meters

This paper presents measurement techniques for multipoint synchronized recordings in offshore wind farms (OWFs). Wind farms in the German North Sea are clustered and connected to the public grid via large-scale HVdc converters. One of the main risks for the OWF operators is the quality of the grid connection provided by the transmission system operator. Dynamic influences originated in the transmission system or neighboring wind farms cause power quality (PQ) disturbances, and may seriously affect the production of a wind farm up to damages of the equipment. This paper shows how to treat the challenges of continuous multipoint synchronized PQ recordings in the OWFs concerning the expected phenomena, meter placement, event source allocation, instrument transformer usage, and time synchronization. Furthermore, it describes the different device categories and how the records of continuous recording high-resolution PQ devices are compared to the ones of a common oscilloscope. After the description of the applied measurement method, with the product standard and the project specific requirements, the catalog of requirements for the measurement system is defined. Linking the PQ data with the theoretic active power production enables the wind farm operator to measure the influence of the grid connection on the yearly energy yield and therewith can figure out the technical and operational improvements.