A new Fault Ride-Through control method for full-converter wind turbines employing Supercapacitor Energy Storage System

摘要

With the increasing penetration of wind power into electric power grids, Fault Ride-Through (FRT) capability has become an obligation for the wind generation units. Previous research has focused on the improvement of FRT capability as long as the generator is still connected to the grid. The existence of distributed generation units in the power system has consequences for the conventional protection devices, as they might become blind to overcurrents and short circuits. This paper proposes the disconnection of the wind power unit when a fault occurs in the grid and the voltage does not recover within a time limit. The energy produced during the fault is stored in a Supercapacitor Energy Storage System, allowing the generator to stay functional for a period of time, despite being disconnected from the grid. In this way, the normal fault-clearing process can take place. Just after reconnection, the generators are able to supply the grid with power, ensuring reliability of the power system.