Parameter Selection Guidelines for Direct-on-Line Permanent Magnet Generators Contemplating Fault-Ride-Through Capability

Direct-on-line (DOL) driven permanent-magnet generators (PMSGs) are often applied in small-scale hydropower plants (< 10 MW). The Commission Regulation (EU) 2016/631 defines the boundary conditions to operate these generators in parallel with the grid. According to the regulation, fault-ride-through (FRT) capability is required in some cases. FRT scenario of PMSGs was studied by simulations and the importance of machine parameters was analyzed. Machine parameters under interest are damper winding resistance and leakage inductance, stator resistance and leakage inductance, saliency, source voltage, total inductance and system inertia. Authors proved that fault-ride-through can be achieved by utilizing smart machine parameters selection without using complicated control systems and auxiliary equipment. FRT simulations are performed for three PMSGs and their capabilities are explored. Results can be used as a guideline in DOL PMSG design for satisfying FRT requirements. The simulation system was also verified with measurements of a 600 kW PMSG data during a fault situation: an incident where the generator was connected to the grid in phase opposition.