Security is fundamental to the operation of smart grid and its advanced metering infrastructure (AMI). Key establishment is the core component in key management schemes and plays a crucial role in ...satisfying the security requirements. In recent years, many key establishment protocols have been proposed in the context of smart grids. However, their high overhead and complexity have undermined their ability to be practically employed in AMI. In this paper, we propose a novel identity-based key establishment protocol which employs elliptic curves at its core and has the lowest computational overhead among current secure protocols, especially at the meter side. We have given a detailed and comparative analysis of both security and computational burden for the proposed protocol as well as the previous efforts. We have evaluated the resilience of different protocols to well-known attacks by discussion, however, for the proposed protocol, we have also used AVISPA tool to formally verify its security. Compared to the previous solutions, the proposed protocol either is more secure or scores higher in performance benchmarks run on the same hardware.
Demand response (DR), distributed generation (DG), and distributed energy storage (DES) are important ingredients of the emerging smart grid paradigm. For ease of reference we refer to these ...resources collectively as distributed energy resources (DER). Although much of the DER emerging under smart grid are targeted at the distribution level, DER, and more specifically DR resources, are considered important elements for reliable and economic operation of the transmission system and the wholesale markets. In fact, viewed from transmission and wholesale operations, sometimes the term ¿virtual power plant¿ is used to refer to these resources. In the context of energy and ancillary service markets facilitated by the independent system operators (ISOs)/regional transmission organizations (RTOs), the market products DER/DR can offer may include energy, ancillary services, and/or capacity, depending on the ISO/RTO market design and applicable operational standards. In this paper we first explore the main industry drivers of smart grid and the different facets of DER under the smart grid paradigm. We then concentrate on DR and summarize the existing and evolving programs at different ISOs/RTOs and the product markets they can participate in. We conclude by addressing some of the challenges and potential solutions for implementation of DR under smart grid and market paradigms.
This paper investigates the use of fractional order (FO) controllers for a microgrid. The microgrid employs various autonomous generation systems like wind turbine generator, solar photovoltaic, ...diesel energy generator, and fuel-cells. Other storage devices like the battery energy storage system and the flywheel energy storage system are also present in the power network. An FO control strategy is employed and the FO-proportional integral derivative (PID) controller parameters are tuned with a global optimization algorithm to meet system performance specifications. A kriging based surrogate modeling technique is employed to alleviate the issue of expensive objective function evaluation for the optimization based controller tuning. Numerical simulations are reported to prove the validity of the proposed methods. The results for both the FO and the integer order controllers are compared with standard evolutionary optimization techniques, and the relative merits and demerits of the kriging based surrogate modeling are discussed. This kind of optimization technique is not only limited to this specific case of microgrid control, but also can be ported to other computationally expensive power system optimization problems.
Nanogrid (NG) cluster (NGC) has the potential to act as one type of basic structure for the future low voltage distribution networks. In this paper, an online energy sharing method is proposed for ...improving the self-sufficiency and photovoltaic (PV) consumption of NGC. First, a hybrid cyber-physical peer-to-peer (P2P) energy sharing framework is proposed, which is a combination of P2P physical system (i.e., NG-to-NG) and client-server cyber system (i.e., NG controllers-central controller). Moreover, an energy sharing strategy with the classification of energy exporting and importing NGs is designed. Considering the stochastic features of PV energy and end user load, an online optimization model and algorithm is formulated based on Lyapunov optimization, as to maximize the self-sufficiency and guarantee the stability of energy storage queues. Finally, in a case study using the realistic data from the residential community, numerical experiments show the effectiveness of the proposed method in improving the self-sufficiency of NGC.
Once a fault in microgrids has been cleared, it is necessary to restore the unfaulted but out-of-service loads as much as possible in a timely manner. This paper proposes a novel fully distributed ...multiagent based load restoration algorithm. According to the algorithm, each agent makes synchronized load restoration decision according to discovered information. During the information discovery process, agents only communicate with their direct neighbors, and the global information is discovered based on the Average-Consensus Theorem. In this way, total net power, indexes and demands of loads that are ready for restoration can be obtained. Then the load restoration problem can be modeled and solved using existing algorithms for the 0-1 Knapsack problem. To achieve adaptivity and stability, a distributed algorithm for coefficient setting is proposed and compared against existing algorithms and a particle swarm optimization based algorithm. Theoretically, the proposed load restoration algorithm can be applied to systems of any size and structure. Simulation studies with power systems of different scale demonstrate the effectiveness of the proposed algorithm.
Dynamic contactless charging is an emerging technology for charging electric vehicles (EVs) on the move. For efficient charging and for proper billing, dynamic charging requires secure communication ...between the charging infrastructure and the EVs that supports very frequent real-time message exchange for EV authentication. In this paper, we propose Portunes+, an authentication protocol for charging pads to authenticate an EVs identity. Portunes+ uses pseudonyms to provide location privacy, allows EVs to roam between different charging sections and receive a single bill, and achieves fast authentication by relying on symmetric keys and on the spatiotemporal location of the EV. We have implemented Portunes+ on RaspberryPi 2 Model B with 900 MHz CPU and 1 GB RAM. Portunes+ allows the EV to generate authentication information within 0.15 ms and allows charging pads to verify the information within 0.11 ms. In comparison, Elliptic Curve Digital Signature Algorithm signature generation and verification take over 9 ms and over 14 ms, respectively.
Demand response has become a key feature of the future smart grid. In addition to having advanced communication and computing infrastructures, a successful demand response program must respond to the ...needs of a power system. In other words, the efficiency and security of a power system dictate the locations, amounts and speeds of the load reductions of a demand response program. In this paper, we propose an event-driven emergency demand response scheme to prevent a power system from experiencing voltage collapse. A technique to design such a scheme is presented. This technique is able to provide key setting parameters such as the amount of demand reductions at various locations to arm the demand response infrastructure. The validity of the proposed technique has been verified by using several test power systems.
This paper describes a wireless sensor-actuator network to monitor and manage thermostatically controlled loads, mainly heating and cooling loads, which accounts for around 50% of the residential ...electricity consumption. A decentralized system is proposed to modify the electrical power demand according to a target demand profile and a set of prefixed constraints, maintaining minimum comfort levels and minimizing the infrastructure requirements. This solution offers the residential customers a flexible, powerful and low-cost tool to modify their power demand profile, avoiding any additional wiring and extending the wireless sensor-actuator networks technology towards small customers, with around 30% share of the global electricity consumption. The proposed system has been implemented and assessed in a university environment, where heating and cooling loads have been monitored and controlled. Acquired data are also included in this paper as well as an example of the forced switching-off time periods applied on the controlled loads, leading to approximately 15% reduction of the peak power demand.
PDF