Emergency Energy Management Strategy For Commercial Building Microgrid Based On Robust Optimization

Commercial building microgrid operates in grid-connected mode under normal conditions,while when the distribution network fails,the commercial building microgrid switches to island mode.Reducing the loss caused by power outage and preserving the power supply should be both taken into account for microgrid emergency energy management.As the PV output uncertainty still exists after power failure,taking into account the uncertainty will be conducive to the reliable operation of the system.This paper presents an emergency energy management strategy based on robust optimization for commercial building microgrid consisting of photovoltaic-battery system.The optimization goal of the emergency energy management is to reduce loss and maintain the power supply,and weighting factors are introduced to weigh the importance of the above two aspects.The constraints include power balance,the operation limit of the controllable loads and energy storage system.In addition,the uncertainty degree is set in the optimization model to represent the conservatism degree of the robust optimization,and the degree of uncertainty determines the influence of the uncertain factors to the problem.The weighting factors and the uncertainty degree of the optimization model can be set flexibly according to the actual situation.Besides,the proposed strategy embraces the thought of rolling optimization to update the PV actual output data regularly to obtain more accurate PV forecast data.And controllable loads regulation scheme is proposed after obtaining the inputs of controllable loads,following the principle of "adjustment first,removal last".The electric vehicle adopts the "flexible adjustment-rigid regulation" two-stage adjustment scheme,and the air conditioning adopts the "odd array-even array" rotation adjustment scheme,which can get the real-time charging rate of the electric vehicle and real-time power consumption of air conditioning after power failure.Comprehensive results obtained from comparative analysis,sensitivity analysis and uncertainty analysis have shown that the proposed strategy is efficacious in adjusting the inputs of controllable loads reasonably to reach the desired goals by changing weighting factors and uncertainty flexibly.