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Environmental concerns and depletion of traditional energy lead to the booming development of renewable distributed generation (RDG) in the past decade. However, due to intermittent nature of renewable energy sources, to what extent RDG could provide capacity to power systems becomes a critical issue to the utility company when implementing long-term system strategic (generation expansion) planning. On the other hand, in a smart-grid frame, the popularization of different varieties of demand-side resources enables the system to operate at more flexible modes ever before. The potential variability in load demand not only introduces additional dynamics and uncertainties to the system, but could also affect the reliability benefits of RDG. Therefore, in practice, to effectively estimate the reliability value of RDG in power systems, the potential interaction between generation- and demand-side must be properly captured. In this paper, a study to assess the capacity credit (CC) of RDG in a context of distributed generation system is performed with consideration of the impacts of demand response (DR). A compound reliability model for DR is presented, which considers the uncertainties involved in both instant response and follow-on load recovery processes. On this basis, an assessment framework for the CC of RDG based on sequential Monte Carlo simulation is developed by which the inter-temporal characteristics of DR resources can be fully captured. The numerical study is implemented based on the IEEE-38 bus test case. The calculation results demonstrate that the CC of RDG would depend on a variety of factors, including penetration level, responsiveness of load demand and the correlations between RDG and DR availability. Also, it is shown that accounting for the underlying effect of DR is of absolute importance, otherwise the CC of RDG might be estimated erroneously in real practices. more...

Wireless sensor network (WSN) hierarchical routing protocols meet the efficient communication of a large-scale network. However, many of them cannot guarantee the optimum choice of the cluster heads because of the lack of comprehensive consideration of the remaining energy of nodes, the distribution within a cluster and the distribution among clusters in the process of choosing the cluster heads. In addition, the single-hop communication among clusters leads to a serious imbalance in the energy of the cluster heads. In view of the above problems, this paper combines the improved particle swarm clustering algorithm with the inter-cluster routing algorithm to form an adaptive energy-efficient clustering routing protocol, referred to as AECRP. Simulation results show that this protocol not only balances the energy consumption of the overall network, delays the death time of the nodes, but also provides more reliable data delivery. more...

In view of the compromise between overhead and performance, this paper proposes a MAODV-X multicast routing protocol by incorporating the excellence of Explicit Multicast with the multicast-tree based routing protocol and stable link repair in Ad Hoc network, which simplifies the MAODV multicast trees by establishing the specific routing table in intermediate nodes in order to reduce the control overhead, predigests the compression code of explicit multicast IP address to lower the complexity of explicit multicast IP header, furthermore, computes the stability coefficient based on maximum entropy in Shannon theorem by taking into account the energy consumption and the congestion level to choose one of the most stable links during the repairing procedure and avoid frequent link repair. The simulation results demonstrate that the MAODV-X protocol performs better in the scenarios of different size of multicast group, different maximum moving speed compared with the counterparts including MAODV and E2M. more...

Distributed generation (DG), which is interlinked with distribution system, will inevitably have an impact to system. In the paper, a reliability evaluation method is proposed, which is based on the analysis to the structure and power flow of distribution system with distributed generation. First, a new concept, the smallest unit, is put forward for improving the fault traversal networks times. The authors use the depth-first search in data structure to divide distribution system into several the smallest units, and propose the islanding operation mode to increase the reliability of the system. Distribution system will be automatically turned into the islanding operation mode once faults occur. To evaluate quantitatively the reliability of distribution system, Monte Carlo simulation method is used by simulating the running status of distribution system. At last, the calculation results of actual case show that the proposed method is available to evaluate the reliability of distribution system with distributed generation. more...