The increasing urgency to transition to renewable power generating technology has dramatically increased the share of IBR plants. In many countries the proportion to installed IBR plants now constitute the majority of generating capacity.

This shift in technology led to a continual erosion of the short circuit capacity of grids, particularly in areas which have a high concentration of IBR plants. Future plants as well as existing plants are now facing connection to a weak grid which has substantially different characteristics as compared with networks where synchronous plants make up the majority.

Grid codes requirements relating to fault ride through of IBR plants were original introduced when grids were significantly stronger. These requirements are becoming increasingly more difficult to comply with in a robust and consistent way. It is not uncommon to have long cables connecting multiple plants clustered in close electrical proximity, each containing many actively controlled devices such as wind turbines, SVCs, and STATCOMs. To ensure the overall plant is grid compliant, each of these devices must be highly and project specifically ‘tuned’ to provide the required dynamic performance.

This paper discusses the challenges faced with grid code requirements related with voltage ride through for wind farms with weak grid connections. This will examine requirements such as high voltage gains, fast active power recovery, voltage response and how they can negatively influence overall wind farm stability and result in a less robust response.

Test rig-based measurements on a single turbine are used to emulate near and distant faults when connected to both weak and strong grid conditions.

Recommendations for grid code modifications are provided based on findings in this paper which will help ensure a more stable and robust wind farm operation.