MPC-Based Black Start and Restoration for Resilient DER-Rich Electric Distribution System

Abstract

For past several years the resiliency of the power grid is severely challenged by extreme events. Black start and restoration scheme (BS&RS) is critical to enhance distribution grid resiliency. Variability in the power supply capacity of distributed energy resources (DERs) and load demand stand against the efficiency of sequential black start restoration of an unbalanced distribution system. An efficient black start restoration scheme must consider forecasted generation and demand profile to assess resource participation and generate valid switching sequence during sequential restoration of distribution grid. This work proposes a novel model predictive control (MPC) based efficient BS&RS strategy for reconfigurable distribution grid with DERs. The proposed algorithm generates optimal switching sequence by coordinating smart switches, black start DERs (BS-DERs) and energy storage systems (ESSs). Active power-frequency droop, reactive power-voltage droop and ramp rate constraints are assigned to BS-DERs for practical purposes. The non-convexity of sequential service restoration problem due to operational constraints of distribution grid, line switches and dynamics of ESS are linearized and solved as a mixed integer linear programming problem (MILP). The proposed scheme is also extended to incorporate errors associated with forecasting, DER capacity and load demand. Results of IEEE 123-bus and 1069-bus systems indicate effectiveness of the proposed approach.

Keywords

• Active distribution grid
• black start restoration
• distributed energy resources
• resource coordination
• centralized optimization
• mixed integer problem