Research For Reliability And Safety-oriented Microgrid Energy Management System

Withtherapiddevelopmentofenergydemandandfurtheradvancementofenergyconservation policies, it has become more urgent than ever to make the transition fromthe energy structure that relies heavily on nonrenewable and high-pollution fossil fuelsto that relies on renewable and clean energy sources. As far as improving the penetra-tion level of renewable energy sources and lowering carbon emissions, the Microgridtechnology that integrates distributed generation units, energy storage units and loaddemand, seamlesslyswitchesbetweenislandmodeandparallelmodewillbeemployedon a large scale. However, the operation of Microgrid not only depends on the grid-tied interface, coordination controller, energy storage converter, the efective energymanagement system (EMS)is also the key to guarantee that the Microgrid is operatedeconomically, reliably and safely. Compared with the traditional energy managementsystem for buck power grid, due to its unique characteristics, for example dual opera-tion mode and relative high penetration level of renewable energy sources, there existsseveral challenges to design the corresponding energy management system. In thisdissertation, the following works has been done:1. Reliability-aware energy scheduling algorithm design for Microgrids. For thefeature that Microgrids can transit to the island mode in case of the upstream griddisturbance, voltage collapse and the event that power quality cannot meet the require-ments, we have got a balance between the two key indicators: operational economicefciency and power supply reliability when design the energy scheduling strategiesfor grid-tied mode. Based on this idea, we have designed a two-stage energy schedul-ing framework, and theoretically analyzed the convergence and asymptotic optimalityof the proposed algorithm. At last, the results of simulation evaluation confrm the fact that the proposed framework can improve the power supply reliability without raisingthe operation cost signifcantly.2. Data integrity attack in distribution system state estimation. For possible vul-nerability in communication protocols that serve for state information exchange be-tweenneighboringpowergridindistributionsystemstateestimation,wehaveproposedastrategythatleveragesthepartialinternalstateinformationthatsenttoitsneighboringareas by the regional power network attacked by malicious attacker, to reconstruct theinternal state information and measurement vector and tamper with the state informa-tion sent from neighboring power grids to the compromised power grid further. Thesimulation results show that the proposed design strategy for attack vectors can bringrelative large error to the fnal state estimate, in some cases it may even disrupt thedistributed state estimation process.