Tie line utilization during power system restoration

This paper identifies some of the critical roles of tie lines during power system restoration. Based on these roles, a systematic approach is developed to evaluate the impact of the availability of tie line assistance on restoration. Using this approach, a tie line expert system module has also been developed to supplement the previously developed EPRI restoration expert system (RES). The enhanced RES can now include available tie line power in recommending a restoration strategy to maximize the system generation capability by modifying the generator startup sequence. Simulation results confirm that outside assistance will improve the overall generation capability and provide an extra dimension to the flexibility of a company´s restoration strategy