Multi-agent system for energy resource scheduling of integrated microgrids in a distributed system

This paper proposes a multi-agent system for energy resource scheduling of an islanded power system with distributed resources, which consists of integrated microgrids and lumped loads. Distributed intelligent multi-agent technology is applied to make the power system more reliable, efficient and capable of exploiting and integrating alternative sources of energy. The algorithm behind the proposed energy resource scheduling has three stages. The first stage is to schedule each microgrid individually to satisfy its internal demand. The next stage involves finding the best possible bids for exporting power to the network and compete in a whole sale energy market. The final stage is to reschedule each microgrid individually to satisfy the total demand, which is the addition of internal demand and the demand from the results of the whole sale energy market simulation. The simulation results of a power system with distributed resources comprising three microgrids and five lumped loads show that the proposed multi-agent system allows efficient management of micro-sources with minimum operational cost. The case studies demonstrate that the system is successfully monitored, controlled and operated by means of the developed multi-agent system.     

Integrating distributed generation into electric power systems: A review of drivers,challenges and opportunities

It is now more than a decade since distributed generation (DG) began to excite major interest amongst electric power system planners and operators, energy policy makers and regulators as well as developers. This paper presents an overview of the key issues concerning the integration of distributed generation into electric power systems that are of most interest today. The main drivers behind the focus on DG integration, especially of the renewable type, in many countries around the world are discussed. A synopsis of the main challenges that must be overcome in the process is presented. Particular emphasis is placed on the need to move away from the fit and forget approach of connecting DG to electric power systems to a policy of integrating DG into power system planning and operation through active management of distribution networks and application of other novel concepts. The paper also analyses the repercussions in transmission system operation and expansion that result from the connection of large amounts of DG of different energy conversion systems focusing on issues related with impacts in steady state operation, contingency analysis, protection coordination as well as dynamic behaviour analysis. A discussion on the possibility of provision of ancillary services by DG is also included. Some results from studies performed in the interconnected Portuguese transmission system are presented and discussed. Some of the opportunities that could be exploited in support of the integration and hence greater penetration of DG into electric power systems are also explored.     

基于PSCAD的多种分布式电源的建模与仿真

在电力系统仿真软件PSCAD／EMTDC仿真环境下,建立了风力发电、微型燃气轮机发电和光伏电池发电三种微电源的仿真模型,对这5种不同DG输出交流电的情况进行比较分析,阐述冷热电联产的必要性。     

基于复合粒子群算法的微电网能量管理策略

微网中的部分分布式能源的功率输出具备一定的随机和性间歇性,很大程度上影响了系统的供电稳定性和可靠性,因此,有效的对微网系统进行能量管理显得至关重要。以往的研究中,多采用优化算法在解决能量管理等问题,但其存在着陷入局部最优解等问题,为有效的解决上述问题,本文引入一种复合粒子群优化算法,综合考虑了微网运行过程的经济性、环保特性以及运行可靠性等要求,建立了微电网能量管理多目标优化数学模型,优化目标是运行成本及环境治理的费用最小。在满足功率平衡、分布式电源输出功率等约束条件下,对模型进行了求解,同时,预测系统内负荷需求的变化情况来确定微网的能量管理策略。通过仿真算例的分析验证改进算法的有效性。     

Integration of distributed energy resources into low voltage grid: A market-based multiperiod optimization model

This paper develops a multiperiod optimization model for an interconnected micro grid with hierarchical control that participates in wholesale energy market to maximize its benefit (i.e. revenues-costs). In addition to the operational constraints of distributed energy resources (DER) including both inter-temporal and non-inter-temporal types, the adequacy and steady-state security constraints of micro grid and its power losses are incorporated in the optimization model. In the presented model, DER are integrated into low voltage grid considering both technical and economical aspects. This integration as a micro grid can participate in wholesale energy market as an entity with dual role including producer and consumer based on the direction of exchanged power. The developed model is evaluated by testing on a micro grid considering different cases and the results are analyzed.     

Economic framework for compensating distributed energy resources: Theory and practice

We offer an economic framework for analyzing the compensation that DERs should receive for energy exported to the grid. This economic framework requires that the prices paid to DER owners be based upon the forward-looking, economic costs that their utility avoids when it buys the energy from the customer. We explain why this results in efficient ‘build or buy’ and ‘purchase and install’ decisions of the utility and DER customer, respectively.