A Distance Protection Method for Offshore Wind Power System based on Negative Sequence Control

The protection of new energy power generation in the power system is gradually increasing, offshore wind power acts as an important part of new energy power generation has broad development prospects. And the submarine cables have also been widely used with the development of offshore wind power technology. The submarine cables are often laid under the sea, so the repairment and replacement of the submarine cables require lots of material costs, and the cables have a high failure rate, so it's of great significance to identify the fault location of cables. In this paper, the topology and control strategies of offshore wind power system are firstly introduced. Secondly, it analyzes the working principle of the distance method based on negative sequence control and infers the calculation formula of fault distance. The distance method can calculate the fault distance and judge the fault location by using the negative sequence component at both ends of the cable. The PSCAD/EMTDC simulation results verify the distance protection method can effectively identify whether the fault occurs in the submarine cables which provides a theoretical basis for the construction of the protection scheme of offshore wind power system.