Assessment of transmission network voltage unbalance in connection of high-speed electrical railway connection

High-speed electrical railway connections are known to cause additional voltage unbalance and other unwanted interactions in the transmission network. In order to assess the influence of different high-speed electrical railway connection options and their characteristics in case of possible Rail Baltic project a comprehensive study was made. This paper provides a discussion about the influence of different type of railway network connection transformers in connection of different load characteristics and contingencies in the railway system. Paper includes an assessment and analysis about possible technical solutions in order to minimize possible adverse interactions between the railway and transmission network. This information is essential for the utilities when planning possible high-speed railway connections and enables to determine possible railway influence and compose adequate connection requirements and specifications.