Implementation of an adaptive protection scheme for a hybrid microgrid system with distributed generations

Abstract

The global increase in the use of renewable energy sources and distributed generation is due to positive environmental impacts and the need to meet energy demand. The protection scheme for traditional radial power systems with unidirectional power flow are not suitable for bidirectional power flow caused by the addition of DGs. The integration of DGs may lead to a loss of coordination between overcurrent protection relays, which could lead to unnecessary disconnections and reduced reliability. Microgrids can operate in grid-connected or island modes. Fault currents are higher during grid-connected mode operation than during island mode operation. Different protection settings are required for relays depending on the mode of operation. Modelling and simulation are conducted in DIgSILENT PowerFactory and RSCAD simulation environments. The modified IEEE 14-bus system is used as a case study, with a 50 MW wind farm as the distributed generation. A protection coordination study is completed for SEL-351 protection relays in grid-connected and islanded modes. Hardware-in-the-loop (HIL) testing of directional overcurrent protection is completed using RTDS and SEL-351A relays. IEC 61850 standard-based GOOSE messages between SEL-351 relays are demonstrated in a laboratory-scale test bench. To address the challenges associated with traditional protection schemes, an adaptive protection scheme is implemented. The adaptive protection algorithm is based on the IEC 61850 GOOSE communication protocol. The adaptive scheme enables real-time monitoring of the network configuration and detects faults in both grid-connected and island modes to ensure MG system reliability. The project focuses on addressing the challenges associated with the integration of distributed generation into the power grid, particularly in the case of microgrids. The emphasis on adaptive protection and real-time monitoring through advanced communication protocols based on IEC 61850 reflects a forward-looking approach to improving the reliability and efficiency of microgrid systems.