Operation Optimization And Protection Strategy For Distributed Networkwith Energy Storage System

The integration of Energy Storage System(ESS)has caused problems of control,siting and sizing,relay protection and so on to smart grid.This thesis focusd on the key technologies such as energy management in cooling-heating-power microgrid,protection constraint based siting and sizing of Battery Energy Storage System(BESS),optimizing strategy of distance protection and adaptive protection scheme,to improve the reliability,stability and economy of smart grid.1.This thesis researched the structure characteristics of microgrid with wind generators,BESS and cooling load;analyzed the operation characteristics of Ice Storage Air Conditioner(ISAC),proposed the energy management and stabilizing strategy of BESS and ISAC,researched the sizing strategy of chilling pumps and BESS under the fixed capacity mode and variable capacity mode respectively;researched the frequency band dividing method,and proposed the punishing function based control algorithm to dispatch the stabilizing command.2.This thesis researched the structure characteristics of microgrid with photovoltaics,BESS and heating load;analyzed the operation characteristics of Air Source Heat Pump(ASHP),proposed the energy management and stabilizing strategy of BESS and ASHP,researched the sizing strategy of ASHP and BESS respectively;and proposed the Double Fuzzy Logic(DFL)algorithm to dispatch the stabilizing command,based on the difficulties of constructing heating model for buildings.3.This thesis researched the siting and sizing problems of BESS integrating into distributed network,analyzed the relay protection constraint to the integration,researched the coding method that is suitable to the structure characteristics of distributed network and operation characteristics of relay protection,researched the improved optimizing algorithm based on Chaotic Algorithm,Immune Algorithm and Tabu Algorithm,and calculated the Protection Access Capacity(PAC)of BESS in each node,so as to improving the reliability of the distributed network.4.This thesis researched the control strategy of BESS,analyzed the operation characteristics under different control strategies when a fault occurred in the distributed network,researched the operation characteristics of distance protection and its application in distributed network,research BESS's impact on distance protection from the perspective of impedance,research the PAC of BESS under the constraint of Zone II distance protection,and calculated the modify coefficient for Zone II distance protection under two different conditions.5.This thesis researched the Wide Area Measurement System(WAMS)based adaptive protection scheme for smart grid,researched the building method of layer-divided node impedance matrix,calculated the equivalent voltage and impedance of upstream network,proposed an adaptive protection scheme,and designed the modules and structure of the adaptive protection,to solve the overcurrent protection problems caused by the structure change of upstream network,change of operation mode and the integration of distributed generators such as BESS.At last,This thesis summarized all the research works of this thesis,pointed out the potential problems,and the further research directions.