Modeling of switching transients in Nysted Offshore Wind Farm and its comparison with measurements : -EMT simulations with Power Factory and PSCAD

Introduction In a near future the offshore wind farms are expected to increase in number and size. At present some development plans in the UK have a total installed capacity higher that 1,000 MW. Some challenges on how to design and build the internal network connecting the wind turbines will arise from the increasing size of the parks. In existing OWFs, the collection grids were designed as any medium voltage underground cable system for distribution. However, there are many differences between the collection grid in the OWP and any distribution system, but the most important of all is the limited access to the park for maintenance and repair due to weather conditions. This limitation narrows the design to obtain high reliability and low maintenance for the equipment. Description The aim of this thesis is to use PSCAD as simulation tools to model the MV collection grid of an operational wind farm and compare it to switching measurements, as well as previous results from Power Factory simulations. The dynamic phenomena in main electrical components like cables, transformers and circuit breakers will be explained, summarized and simulated. The model of the cables, transformers and switchgear will be created based on available information from the manufacturer and the capabilities of the simulation programs. The results from PSCAD and Power Factory will be compared between them and the measurements done in Nysted Wind Park, to conclude whether or not the programs can be trusted. Specifically the closing of the line breaker for a row on the transformer platform will be simulated, as well as the connection of one/several turbines, with the intention of compute the voltage dip due to the transformer energization. Link DONG energy