| With the rapid development of smart distribution grid(SDG), the applications of smart meters, distribution automation equipment, and SCADA have been gradually popularized, which creates good conditions for the integration and practical use of advanced application and analysis software for SDG. Distribution fast simulation and modeling(DFSM) is a set of decision making tools specially dedicated for the operation, planning and management of distribution systems. DFSM can provide accurate and real-time simulation and analysis for distribution system operators to ensure automatic and continuous system operation at optimal state. With the wide availability of distributed generators(DGs) and the fast development of power electronic devices, DC power distribution network and advanced power electronic devices has become a hot topic in the distribution network. Facing this new development situation, various applications and functions of DFSM need be further improved. In this dissertation, some key functions and technologies of DFSM are studied under the smart distribution system with multiple DC components. The main contributions are highlighted as follows:(1) Steady state models of smart distribution grid are summarized, including the AC network components, DC network components, DGs, soft normally open point(SNOP), and etc. The mathematical model of a three-phase AC-DC converter is presented considering the asymmetric characteristics of distribution network, and the corresponding control modes are discussed. The study on modeling methods of DC distribution network and new electronic devices will enrich and extend the modeling ability of DFSM.(2) An AC-DC hybrid power flow calculation method is proposed with adequate consideration of various control modes of AC-DC converter. The roles of DGs, energy storage devices, and SNOP in the power flow calculation are well addressed through reactive power compensation for the non-PQ nodes. The proposed method enhances the DFSM’s capability of power flow calculation and expands its range of applications.(3) A novel optimization model for the operation of distribution system with SNOP is established to minimize the total operating costs of SDG with power flow constraints, voltage level constraints, branch current constraints, SNOP operation boundary constraints and so on. The optimization model is compared with network reconfiguration, and the potential advantages and benefits of SNOP are analyzed from both static and dynamic perspectives. The integration and application of SNOP enriches the control means of DFSM and improve its capability of power flow optimization.(4) An optimal operation strategy for distribution system with energy storage is proposed based on the time-series power flow frame considering the operation boundary of energy storage. For solving this large-scale optimization model, a novel and fast method based on conic programming algorithm is proposed to accelerate the DFSM’s computing speed, and meet the real-time requirements of distribution system operation. |
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