•Bibliometric analysis and systematic literature review for resilience of water distribution networks between 2000 and 2021.•Specifying and visualizing influential authors, publications, and citation ...patterns.•Identification of scientific collaboration, thematic clusters, and current trends.•Analysing resilience metrics, dimensions, and capacities of water distribution networks.•Discussion of limitations, challenges, and future directions.
Infrastructure resilience is quite an emerging topic that has captured tremendous interest among researchers and practitioners. Resilience of water distribution networks (WDNs) established itself as one of the most promising and growing hotspots in the realm of sustainable management against extreme hazards. This study aims to delve into the manifestation, genesis, progression, and gaps of the resilience research related to WDNs. The study comprises a meticulous quantitative and qualitative delineation of 184 articles between 2000 and 2021 utilizing a combination of bibliometric analysis and systematic review. Network analysis (co-word, co-citation, co-author, and clustering) was employed to determine and visualize the prominent topics, influential publications, citation patterns, and productive authors and countries along with their interconnections. Subsequently, text mining tools and critical content analysis were adopted to explore extant research characteristics and gaps. Three thematic clusters were identified 1) hydraulic simulation for resilience assessment, 2) surrogate measures and comparative studies, and 3) connectivity and topological metrics. A bias in the research literature towards classical resilience assessment overlooking organizational, adaptive, and interdependency aspects was reported. The in-depth understanding provided in this study is expected to unlock new research and investment opportunities in the domain of WDNs resilience.
Earth faults is a challenging fault type to locate in resonant grounded networks due to their naturally low fault current, and the problem increases with an increased fault impedance. This paper ...describes the detailed implementation and laboratory testing of a method for detection, location and clearing of earth faults with very small fault currents. The method consists of two indicators used in the fault detection stage, where their simultaneous operation ensures selective fault detection and faulty feeder selection. One of these indicators also enables continuous fault indication throughout a sectionalizing process. The laboratory tests demonstrate that both indicators function as intended, and it is the current sensors which ultimately limit the attainable sensitivity. Faults up to 15 kΩ were detected successfully in the laboratory network based on phase current measurements, while the sectionalizing indicator showed much higher sensitivity and functioned as intended in a 50 kΩ fault. Measurements from one field test in a 22 kV network corroborate the laboratory results and demonstrate the expected earth fault indicator response.
This paper presents a method for detecting, locating and clearing low‐current earth faults in resonant grounded networks. The implementation of the fault detection logic is described in detail, and the method is verified experimentally using a physical 400 V laboratory network equivalent.
This study explores peer-to-peer (P2P) electricity trading, emphasizing not just the export and consumption, but also the feasible physical supply of electricity and the use of distribution network ...assets. Building on a transaction-oriented dynamic power flow tracing model, a novel P2P market architecture is proposed. This architecture integrates the electricity market with the power network, considering technical constraints, network losses, and asset usage. The network is segmented into potential markets using second-order cone programming (SOCP), with an optimization problem introduced for loss-allocation. This problem merges network physical analysis and variable outputs from distributed energy resources (DERs). A graph-based P2P electricity trading model is designed to determine optimal transaction cost allocation and maximize benefits for both DERs and consumers. A case study on a modified IEEE 33-node test feeder substantiates the benefits of this market structure, demonstrating increased revenues for DERs and reduced bills for consumers compared to traditional feed-in-tariffs.
•Build a new P2P energy market model supported by dynamic power flow tracing.•Propose an optimized market segmenting strategy based on identifying power transactions.•Define the market boundaries in a physical system technically and economically.•Increase the DER owners’ revenue that varied between £1264 and £1910.•Reduced consumers’ bills up to £1736 compared with a traditional FiT model.
Abstract
Precise energy management in distribution power system requires high‐precision time synchronization among large‐scale deployed devices. Multiple clock sources‐based time synchronization ...possesses advantages of reliability, high precision, and robustness, but still faces several challenges such as coupling between time synchronization error and delay, as well as different timescales between clock source and clock weight optimization. In this paper, a multi‐clock source time synchronization model is constructed and a problem is formulated to minimize the synchronization error and delay through jointly optimizing large‐timescale clock source selection and small‐timescale weight selection. A reinforcement learning‐based multi‐timescale multi‐clock source time synchronization algorithm named RL‐M
2
is proposed to solve the formulated problem from a learning perspective. Besides, a lossless switching method is proposed to address the switching problem for multiple clock sources. Simulation results demonstrate the superior performance of RL‐M
2
and the lossless switching method in time synchronization delay and error.
We study a multi-access variant of the popular coded caching framework, which consists of a central server with a catalog of <inline-formula> <tex-math notation="LaTeX">N </tex-math></inline-formula> ...files, <inline-formula> <tex-math notation="LaTeX">K </tex-math></inline-formula> caches with limited memory <inline-formula> <tex-math notation="LaTeX">M </tex-math></inline-formula>, and <inline-formula> <tex-math notation="LaTeX">K </tex-math></inline-formula> users such that each user has access to <inline-formula> <tex-math notation="LaTeX">L </tex-math></inline-formula> consecutive caches with a cyclic wrap-around and requests one file from the central server's catalog. The server assists in file delivery by transmitting a message of size <inline-formula> <tex-math notation="LaTeX">R </tex-math></inline-formula> over a shared error-free link and the goal is to characterize the optimal rate-memory trade-off. This setup was studied previously by Hachem et al. , where an achievable rate and an information-theoretic lower bound were derived. However, the multiplicative gap between them was shown to scale linearly with the access degree <inline-formula> <tex-math notation="LaTeX">L </tex-math></inline-formula> and thus order-optimality could not be established. A series of recent works have used a natural mapping of the coded caching problem to the well-known index coding problem to derive tighter characterizations of the optimal rate-memory trade-off under the additional assumption that the caches store uncoded content. We follow a similar strategy for the multi-access framework and provide new bounds for the optimal rate-memory trade-off <inline-formula> <tex-math notation="LaTeX">R^{*}(M) </tex-math></inline-formula> over all uncoded placement policies. In particular, we derive a new achievable rate for any <inline-formula> <tex-math notation="LaTeX">L \ge 1 </tex-math></inline-formula> and a new lower bound, which works for any uncoded placement policy and <inline-formula> <tex-math notation="LaTeX">L \ge K/2 </tex-math></inline-formula>. We then establish that the (multiplicative) gap between the new achievable rate and the lower bound is at most 2 independent of all parameters, thus establishing an order-optimal characterization of <inline-formula> <tex-math notation="LaTeX">R^{*}(M) </tex-math></inline-formula> for any <inline-formula> <tex-math notation="LaTeX">L\ge K/2 </tex-math></inline-formula>. This is a significant improvement over the previously known gap result, albeit under the restriction of uncoded placement policies. Finally, we also characterize <inline-formula> <tex-math notation="LaTeX">R^{*}(M) </tex-math></inline-formula> exactly for a few special cases.
Buried pipes comprise a significant portion of assets of a water utility. With time, these pipes inevitably fail. Failure prediction enables infrastructure managers to estimate long-term failure ...trends for budgetary planning purposes and identify critical pipes for preventive intervention planning. For short-term prioritization, machine learning based algorithms appear to have superior predictive performance compared to traditional survival analysis based models. These models are typically stratified by material resulting in the exclusion of newer pipe materials such as polyethylene and corrosion-protected ductile iron, despite their prevalence in modern networks. In this paper, an application of an existing methodology is presented to estimate time to next failure using artificial neural networks (ANNs). The novelties of the approach are 1) including material as an input parameter instead of training several material-specialized models and, 2) addressing right-censored data by combining soft and hard deterioration data. The model is intended for use in short-term prioritization.
A new continuation power flow method is proposed, which is an extension of the popular backward/forward sweep power flow (BFS) for distribution network. The different reasons for the divergence of ...Newton's algorithm and fixed-point iteration algorithm near the saddle node bifurcation point have been investigated extensively. Loop-analysis-based power flow (LBPF) is a revised version of BFS, which belong to fixed-point iteration algorithm and its convergence remains satisfactory in a meshed network. Based on LBPF, a tailored continuous power flow method is developed, which can be used as a voltage stability analysis tool for both radial and meshed distribution networks. Numerical test results are presented to validate the proposed procedure.
Efficiency pursuit of the distribution system operation should be on the premise of security. This study proposes the network reconfiguration (NR) approach comprehensively considering N−1 security ...and network loss. A new approach called distribution system security region (DSSR) is first applied in NR problem. The DSSR is the feasible operation space of a system within N−1 security criterion and can quantify the N−1 security margin. Then, the NR is formulated by using the minimum network loss as objective function and the N−1 security margin, which is provided by the DSSR, as constraints. Moreover, the security margin constraints can be customised for each feeder individually, yielding proper compromises between security-related and efficient concerns. Different NR results for multiple security and efficiency requirements are presented on an extended IEEE-RBTS test system. Compared with the traditional minimum-loss NR, the proposed approach reduces the network loss as much as possible with desired security margin, well balancing the security and efficiency of NR.
This paper presents a mixed-integer second-order cone programing (MISOCP) model to solve the optimal operation problem of radial distribution networks (DNs) with energy storage. The control variables ...are the active and reactive generated power of dispatchable distributed generators (DGs), the number of switchable capacitor bank units in operation, the tap position of the voltage regulators and on-load tap-changers, and the operation state of the energy storage devices. The objective is to minimize the total cost of energy purchased from the distribution substation and the dispatchable DGs. The steady-state operation of the DN is modeled using linear and second-order cone programing. The use of an MISOCP model guarantees convergence to optimality using existing optimization software. A mixed-integer linear programing (MILP) formulation for the original model is also presented in order to show the accuracy of the proposed MISOCP model. An 11-node test system and a 42-node real system were used to demonstrate the effectiveness of the proposed MISOCP and MILP models.
In this paper, the feasibility of peer-to-peer (P2P) energy trading in a voltage-constrained grid-connected network is studied. In particular, a local voltage management scheme is proposed that takes ...network constraints into consideration to instruct the prosumers to trade energy frequently in the P2P market. A coalition graph game-based P2P energy trading framework is developed, in which prosumers can form the coalition to negotiate and decide on the energy trading parameters, such as trading quantities and prices. The Myerson value rule is used to allocate the total payoff of the proposed game fairly among the participating prosumers. Further, the stability of the proposed coalition structure is confirmed. Several simulation results are provided to verify the effectiveness of the developed P2P trading model. The simulation results show that the proposed P2P trading framework can enable prosumers to export power without causing high voltage problem in the network, and help prosumers cut down a significant portion of their overall electricity costs compared to the feed-in-tariff and coalition game model without mutual negotiations.
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