Performance of out-of-step tripping protection under renewable integration

In future power systems, highly increased renewable integration is expected to meet global decarbonisation targets. The risks and uncertainties brought about by renewable integration will challenge system stability. This study analyses the impact of the increased level of renewable energy sources integration on system transient stability and out-of-step tripping (OST) protection. To this end, the performance of OST protection is assessed in terms of the ability to prevent system instability under different contingencies. A modified two-area test system and Great Britain (GB) 29-zone system integrated with a dynamic model of wind turbines are selected as test systems. A systematic approach is adopted to design a specific OST protection scheme for each test system and to obtain suitable relay settings. An extensive number of simulation studies are carried out using DIgSILENT PowerFactory to assess the performance of the designed schemes under different renewable integration levels. Conclusions are made based on the obtained results, which all imply that revision of the existing OST protection scheme will be inevitably needed.