Reactive power based directional protection for distributed generation during undervoltage conditions at PCC

As the integration of distributed power generation into medium-voltage (MV) networks increases, ensuring grid stability is vital. Traditional methods of disconnecting distributed generation (DG) during network faults can delay system recovery. To address this, grid codes impose fault ride-through (FRT) requirements that enable DGs to support network stability. During FRT, DGs must be prevented from consuming reactive power, which can lead to grid instability. This paper introduces a reactive power-based directional protection (QDUVP) application to identify these situations. The application selectively disconnects DGs that consume reactive power during FRT events by monitoring voltage levels and reactive power flow. This ensures that healthy DGs can continue to support the grid while avoiding unstable conditions. Simulation studies conducted using PSCAD have confirmed the effectiveness of this protection application in isolating faulty DGs and maintaining grid stability during grid disturbances. The proposed approach allows for more resilient grid operation, helping to accommodate the increasing presence of distributed energy resources while ensuring that the overall system remains reliable and stable.