This study presents a novel networked microgrid (MG)-aided approach for service restoration in power distribution systems. This study considers both dispatchable and non-dispatchable distributed ...generators (DGs), and energy storage systems. The uncertainty of the customer load demands and DG outputs are modelled in a scenario-based form. A stochastic mixed-integer linear program is formulated with the objective to maximise the served load, while satisfying the operation constraints of the distribution system and MGs. The interaction among MGs is modelled using the type 1 special ordered set. Two approaches are developed and compared: (i) a centralised approach where all MGs are controlled by a distribution system operator, and (ii) a decentralised approach where the distribution system and MGs are managed by different entities. The proposed restoration models are tested on a modified IEEE 123-bus distribution system. The results demonstrate the advantages of leveraging networked MGs to facilitate service restoration.
This paper presents a new planning expansion model of an electricity and natural gas distribution system that has high penetration of distributed generation based on natural gas. The model entails ...lower investment costs as compared to traditional planning models that consider both systems (electricity and natural gas) as independent networks. This model is especially convenient for utilities that own both systems, as electricity and natural gas customers can derive benefits (via electricity or natural gas tariffs) if there are significant savings in investment costs. For fast-growing economies, the merging of electricity and natural gas distribution systems is seen as a promising business opportunity in which economies of scope can have lower investment costs, so there is a definite need for this type of approach.
AbstractThis paper proposes a system-characteristics and graph theory–based water distribution system (WDS) model classification scheme that is based on system function and topology. Various ...parameters are examined to determine the most adequate parameter(s) for describing a WDS. The classification scheme is applied to a single hypothetical and 25 real systems. The primary indicator to classify a WDS function (transmission or distribution networks) is the length-weighted average pipe diameter. The average nodal demand and histogram of total length of each pipe diameter are applied as secondary measures. A new parameter, defined as the branch index (BI), is used to further classify a branched network by estimating the degree of branching within a WDS. The degree of looping and a second level of classification are based on the meshedness coefficient (MC), but only after the system is reduced to eliminate nonessential nodes. BI values are compared with other system-structure metrics in the literature including link density (LD), average node degree (AND), MC, and clustering coefficient (CC). To that end, Pearson correlation coefficients are computed across the set of other metrics for 26 systems. The correlation analysis reveals that several graph-theory system-structure metrics are highly correlated.
•This paper discusses the applications of smart meters for protection and monitoring of emerging active distribution systems in a smart grid environment.•A number of possible applications are ...suggested and each of the suggested application can eventually become a research project.•This paper is of seminal nature in the area of smart meters and once published, will get a lot of air.
Emerging distribution systems are experiencing large proliferation of smart meters. However, many groups have expressed reluctance in implementing the idea of smart meters. Health hazard due to exposure to radio waves, fire risk, security and privacy of customer information are some of the concerns raised by the consumers. Another important concern is the increased expenses of the utility providers with limited benefits resulting from detailed cost-benefit-analysis. Existing applications of smart meters have not been able to justify the importance of it in some situations. As evidenced in many articles, world-wide roll-out projects and the implementations of smart meters have been hindered with obstacles many times. Therefore, this sluggish progress and growing negative concerns originate the requirement of enhancement of new applications of smart meters in areas such as protection and monitoring of emerging distribution system. Protection and monitoring of distribution systems are two major aspects that any distribution provider is always concerned of and interested to explore smart approaches for management of it. This paper is proposing some potential applications in protection and monitoring of distribution system by the means of smart meters. The underneath expectation is that it will facilitate the required justifications in order to promote the future smart metering projects.
Trend-setting countries have promoted or even employed an increased number of electric vehicles (EVs) and other distributed energy resources (DERs) in their power systems. This development has ...triggered new and increasing challenges in the distribution system planning and operation, whereby the distribution systems must adapt to the increased share of DERs. However, EVs may also offer new opportunities and can be used to support the grid by providing several local and global power- and energy-based services. This paper presents a review and classification of the services potentially available from EVs for distribution systems, referred to as EV distribution system services (EV-DSS). A detailed description of recent services and approaches is given, and an assessment of the maturity of EV-DSS is provided. Moreover, challenges and prospects for future research are identified, considering key topics, such as the design of the market framework, economic assessment, battery degradation, and the impacts of the transmission system operator service provision by EVs on distribution networks. Thus, this paper offers a tool for stakeholders concerning services available from EVs and provides a broad literature framework that can be used as a base for further investigations. It is aligned with the current requirements to move toward the realistic implementations of EV-DSS.
Distribution system reconfiguration is a complex combinatorial optimisation problem. Finding a globally optimal solution to this problem in a short span of time is a challenging task. Two different ...network reconfiguration methodologies, namely a look-up table-based algorithm and a Pareto-optimisation-based algorithm have been discussed. Power loss minimisation and reliability maximisation are taken as objectives for both the methodologies when the system is in the normal operating state. The same algorithms also work for maximum service restoration under the post-fault condition. For reliability assessment in the presence of distributed generators (DGs), an algorithm is also proposed using the probabilistic model of components. In the other algorithm, reconfiguration is performed in the presence of DGs using a look-up table. The look-up table is prepared with the help of the proposed Pareto-optimisation-based reconfiguration algorithm to train the system for various loading conditions. The feasibility and effectiveness of the proposed methods are demonstrated using the IEEE 34- and IEEE 123-bus unbalanced radial distribution systems under normal and faulty conditions. The algorithms are also tested on a 13-bus practical distribution system in the field.
Matrix is one of the convenient means for depicting/illustrating a graph on the computer. In this study, the notion graph-theory in conjunction with matrix algebraic operations has been adopted for ...solving the load-flow problem of three-phase distribution systems (radial and meshed). Five significant matrices, path impedance (PI), loads beyond branch (LB), path drop (PD), slack bus to other buses drop (SBOBD), load flow matrix (LFM), and straight-forward matrix operations have been utilised to attain the load-flow solutions. The aforementioned matrices reveal the system's topology and pertinent information about the operating characteristics of the distribution system during LF studies. This algorithm is formulated entirely on various matrices formulation and computations, even at the stage of upgrading the voltage at every individual bus. Owing to the aforementioned reasons, this LF methodology is computationally efficient for large-sized distribution systems. Moreover, the distributed generations (DGs) modelled as PQ and PV buses are incorporated into the proposed load-flow algorithm. A generalised breakpoint matrix has been derived to compute the mesh breakpoint and PV breakpoint injections simultaneously. The effectiveness of the proposed methodology has been tested on several standard distribution systems. The test outcome shows the viability and accuracy of the proposed method.
This paper proposes a novel stochastic planning model for AC-DC hybrid distribution systems (DSs). Taking into account the possibility of each line/bus being AC or DC, the model finds the optimal ...AC-DC hybrid configuration of buses and lines in the DS. It incorporates consideration of the stochastic behavior of load demands and renewable-based distributed generators (DGs). The stochastic variations are addressed using a Monte-Carlo simulation technique. The objective of the planning model is the minimization of DS installation and operation costs. The optimal planning solution is obtained by dividing the hybrid planning problem into two nested optimization problems: 1) the main problem is formulated using a genetic algorithm (GA) to search for the optimal AC-DC configuration and 2) the subproblem is used for determining the optimal power flow solution for each configuration generated by the GA. The proposed model has been employed for finding the optimal configuration for a suggested case study that included photovoltaic panels, wind-based DG, and electric vehicle charging stations. The same case study was also solved using a traditional AC planning technique in order to evaluate the effectiveness of the proposed model and the associated cost-savings. The results demonstrate the advantages offered by the proposed model. The proposed framework represents an effective technique that can be used by DS operators to identify the optimal AC-DC network configuration of future DSs.
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