Time-interval based volt/VAr control in distribution systems

2003 ◽  
Author(s):  
Hu Zechun ◽  
Wang Xifan ◽  
Chen Haoyong
Keyword(s):  
Distribution Systems ◽  
Time Interval

scholarly journals WDSchain: A Toolbox for Enhancing the Security Using Blockchain Technology in Water Distribution System

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1944
Author(s):  
Haitham H. Mahmoud ◽  
Wenyan Wu ◽  
Yonghao Wang
Keyword(s):  
Time Series ◽  
Distribution Systems ◽  
Water Distribution ◽  
Time Series Data ◽  
Series Data ◽  
Process Time ◽  
Time Interval ◽  
Security Level ◽  
Data Validation ◽  
Simulated Time

This work develops a toolbox called WDSchain on MATLAB that can simulate blockchain on water distribution systems (WDS). WDSchain can import data from Excel and EPANET water modelling software. It extends the EPANET to enable simulation blockchain of the hydraulic data at any intended nodes. Using WDSchain will strengthen network automation and the security in WDS. WDSchain can process time-series data with two simulation modes: (1) static blockchain, which takes a snapshot of one-time interval data of all nodes in WDS as input and output into chained blocks at a time, and (2) dynamic blockchain, which takes all simulated time-series data of all the nodes as input and establishes chained blocks at the simulated time. Five consensus mechanisms are developed in WDSchain to provide data at different security levels using PoW, PoT, PoV, PoA, and PoAuth. Five different sizes of WDS are simulated in WDSchain for performance evaluation. The results show that a trade-off is needed between the system complexity and security level for data validation. The WDSchain provides a methodology to further explore the data validation using Blockchain to WDS. The limitations of WDSchain do not consider selection of blockchain nodes and broadcasting delay compared to commercial blockchain platforms.

scholarly journals Nonclassical Attack on a Quantum Key Distribution System

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 509
Author(s):  
Anton Pljonkin ◽  
Dmitry Petrov ◽  
Lilia Sabantina ◽  
Kamila Dakhkilgova
Keyword(s):  
Optical Communication ◽  
Distribution System ◽  
Quantum Key Distribution ◽  
Distribution Systems ◽  
System Development ◽  
Experimental Studies ◽  
Key Distribution ◽  
Time Interval ◽  
Quantum Protocol ◽  
Research Show

The article is focused on research of an attack on the quantum key distribution system and proposes a countermeasure method. Particularly noteworthy is that this is not a classic attack on a quantum protocol. We describe an attack on the process of calibration. Results of the research show that quantum key distribution systems have vulnerabilities not only in the protocols, but also in other vital system components. The described type of attack does not affect the cryptographic strength of the received keys and does not point to the vulnerability of the quantum key distribution protocol. We also propose a method for autocompensating optical communication system development, which protects synchronization from unauthorized access. The proposed method is based on the use of sync pulses attenuated to a photon level in the process of detecting a time interval with a signal. The paper presents the results of experimental studies that show the discrepancies between the theoretical and real parameters of the system. The obtained data allow the length of the quantum channel to be calculated with high accuracy.

An integrated approach for three-dimensional capacitated vehicle routing problem considering time windows

2020 ◽  
Vol 15 (3) ◽  
pp. 995-1015
Author(s):  
Ashkan Ayough ◽  
Behrooz Khorshidvand ◽  
Negah Massomnedjad ◽  
Alireza Motameni
Keyword(s):  
Vehicle Routing ◽  
Distribution Systems ◽  
Time Windows ◽  
Three Dimensional ◽  
Medium Size ◽  
Time Interval ◽  
Routing Problem ◽  
Content Type ◽  
Large Size ◽  
Capacitated Vehicle

Purpose As a critical problem in sophisticated distribution systems, vehicle routing plays a pivotal role in dealing with time windows and capacities constraints. The purpose of this paper is to addresses a new integrated model to incorporate both three-dimensional and time windows aspects of the routing problem. First, capacitated vehicle routing decisions are made subject to a soft time interval to meet the customers’ demands. Afterward, these decisions are entered into the three-dimensional loading problem. Design/methodology/approach The problem is solved using generalized algebraic modeling system software in small-size problems. The problem is NP-hard and requires an efficient solution methodology. For this purpose, a hybrid algorithm has been proposed to solve the large-size problems. The efficiency of this algorithm is checked by making comparisons with exact solutions for small and medium size test problems, and with the related literature for large size problems. Findings The numerical experiments show that the proposed model covers more effectively the broader aspects of the transportation problem. Furthermore, the proposed algorithm supports competitive and satisfactory results by giving reasonable outputs in comparison with previous studies. Originality/value The main purpose of this integration is to achieve minimum total transportation costs, which cannot be guaranteed without applying two referred constraints, simultaneously.

scholarly journals Micro-Degradation Characteristics and Mechanism of ZnO Varistors under Multi-Pulse Lightning Strike

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2620
Author(s):  
Chunlong Zhang ◽  
Hongyan Xing ◽  
Chunying Li ◽  
Ran Cai ◽  
Dongbo Lv
Keyword(s):  
Boundary Layer ◽  
Grain Boundary ◽  
Distribution Systems ◽  
Pulse Current ◽  
Low Voltage ◽  
Grain Structure ◽  
Lightning Strike ◽  
Time Interval ◽  
Zno Varistor ◽  
Zno Varistors

In view of the problem that ZnO varistors are often subjected to thermal breakdown and deterioration due to lightning strikes in low-voltage power distribution systems, this article used a 8/20 µs multi-pulse surge current with a pulse time interval of 50 ms to perform shock experiments on ZnO varistors. SEM scanning electron microscope and an XRD diffractometer were used to analyze the structure of the grain boundary layer and the change of the crystalline phase material of ZnO varistor under the action of a multi-pulse current. The damage mechanism of ZnO varistor under the multi-pulse current was studied at the micro level. The results show that the average impact life of different types of ZnO varistor is significantly different. It was found that the types of trace elements and grain size in the grain boundary layer will affect the ability of ZnO varistor to withstand multi-pulse current. As the number of impulses increases, the grain structure of the ZnO varistor continues to degenerate. The unevenness of internal ion migration and the nonuniformity of the micro-grain boundary layer cause the local energy density to be too large and cause the local temperature rise to be too high, which eventually causes the internal grain boundary to melt through, and the local high temperature may cause the Bi element in the ZnO varistor to change in different crystal phases.

scholarly journals Optimal Phase Load Balancing in Low Voltage Distribution Networks Using a Smart Meter Data-Based Algorithm

2020 ◽  
Author(s):  
Gheorghe Grigoras ◽  
Bogdan-Constantin Neagu ◽  
Mihai Gavrilas ◽  
Ion Tristiu ◽  
Constantin Bulac
Keyword(s):  
Load Balancing ◽  
Distribution Systems ◽  
Energy Savings ◽  
Low Voltage ◽  
Distribution Networks ◽  
Hybrid Structure ◽  
Optimal Operation ◽  
Time Interval ◽  
Voltage Distribution ◽  
Load Balancing Algorithm

In the electric distribution systems, the “Smart Grid” concept is implemented to encourage energy savings and integration of the innovative technologies, helping the Distribution Network Operators (DNOs) in choosing the investment plans which to lead the optimal operation of the networks and increasing the energy efficiency. In this context, a new phase load balancing algorithm was proposed to be implemented in the low voltage distribution networks with hybrid structures of the consumption points (switchable and non-switchable consumers). It can work in both operation modes (on-line and off-line), uploading information from different databases of the DNO which contain: the consumers’ characteristics, the real loads of the consumers integrated into the Smart Metering System (SMS), and the typical load profiles for the consumers non-integrated in the SMS. The algorithm was tested in a real network, having a hybrid structure of the consumption points, on a time interval by 24 hours. The obtained results were analyzed and compared with other algorithms from the heuristic (Minimum Count of Loads Adjustment algorithm) and the metaheuristic (Particle Swarm Optimization and Genetic Algorithms) categories. The best performances were provided by the proposed algorithm, such that the unbalance coefficient resulted in the smallest value (1.0017). The phase load balancing led to the following technical effects: decreasing the average current in the neutral conductor with 94% and for the energy losses with 61.75 %, and increasing the minimum value of the phase voltage at the farthest pillar with the 7.14 %, compared to the unbalanced case.

Using a new pressure index for water distribution systems upgradation improvement evaluation

2016 ◽  
Vol 16 (5) ◽  
pp. 1339-1348
Author(s):  
Savalan Pour Akbarkhiavi ◽  
Monzur Alam Imteaz
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Water Distribution Systems ◽  
Water System ◽  
Point Of View ◽  
Level Of Service ◽  
Time Interval ◽  
Network Systems ◽  
Pressure Index

Potable water distribution systems (WDS) require upgrade strategies based on a pre-defined time interval which is identified by the responsible water authorities. The main goal of a potable water system upgrade is maintaining the standard and acceptable level of service after the occurrence of increases in the serviced population, asset ageing, and/or development of the serviced area. Defining the level of service varies by location according to the codes and regulations adopted by the water authority. In general, two main factors are notable in planning of WDS upgrade strategies: (1) the ‘level of service’ and (2) the ‘upgrade cost’. In the presented paper, a new index has been introduced to evaluate the level of service for WDS from a pressure point of view. The new index that is presented in this paper is named the ‘Pressure Index (PI)’, and incorporates a number of water connections for five different pressure regimes. As a case study, three existing water network systems in the Castlemaine township area, located in central Victoria, Australia, have been investigated and the relationship between the ‘upgrade costs’ and improvement in PI factors is presented.

scholarly journals A sliding window algorithm for energy distribution system with storage

2021 ◽  
Vol 6 (11) ◽  
pp. 11815-11836
Author(s):  
Jean-Paul Chehab ◽  
◽  
Vivien Desveaux ◽  
Marouan Handa
Keyword(s):  
Energy Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
Optimization Problems ◽  
Piecewise Linear ◽  
Sliding Window ◽  
Real Data ◽  
Optimization Methods ◽  
Computational Time ◽  
Time Interval

<abstract><p>This work is devoted to study optimization problems arising in energy distribution systems with storage. We consider a simplified network topology organized around four nodes: the load aggregator, the external grid, the consumption and the storage. The imported power from the external grid should balance the consumption and the storage variation. The merit function to minimize is the total price the load aggregator has to pay in a given time interval to enforce this balance.</p> <p>Two optimization problems are considered. The first one is linear and standard. It can be solved through classical optimization methods. The second problem is obtained from the previous one by taking into account a power subscription, which makes it piecewise linear. We establish mathematical properties on both these models.</p> <p>Finally, a new method based on a sliding window algorithm is derived. It allows to reduce drastically the computational time and makes feasible real time simulations. Numerical results are performed on real data to highlight both models and to illustrate the performance of the sliding window algorithm.</p></abstract>

Focusing of Visuospatial Attention

2001 ◽  
Vol 15 (4) ◽  
pp. 256-274 ◽  
Author(s):  
Caterina Pesce ◽  
Rainer Bösel
Keyword(s):  
Reaction Times ◽  
Visual Space ◽  
Spatial Relation ◽  
Stimulus Onset ◽  
Visuospatial Attention ◽  
Task Demands ◽  
Time Interval ◽  
Behavioral Studies ◽  
Task Conditions ◽  
Simple Rt

Abstract In the present study we explored the focusing of visuospatial attention in subjects practicing and not practicing activities with high attentional demands. Similar to the studies of Castiello and Umiltà (e. g., 1990) , our experimental procedure was a variation of Posner's (1980) basic paradigm for exploring covert orienting of visuospatial attention. In a simple RT-task, a peripheral cue of varying size was presented unilaterally or bilaterally from a central fixation point and followed by a target at different stimulus-onset-asynchronies (SOAs). The target could occur validly inside the cue or invalidly outside the cue with varying spatial relation to its boundary. Event-related brain potentials (ERPs) and reaction times (RTs) were recorded to target stimuli under the different task conditions. RT and ERP findings showed converging aspects as well as dissociations. Electrophysiological results revealed an amplitude modulation of the ERPs in the early and late Nd time interval at both anterior and posterior scalp sites, which seems to be related to the effects of peripheral informative cues as well as to the attentional expertise. Results were: (1) shorter latency effects confirm the positive-going amplitude enhancement elicited by unilateral peripheral cues and strengthen the criticism against the neutrality of spatially nonpredictive peripheral cueing of all possible target locations which is often presumed in behavioral studies. (2) Longer latency effects show that subjects with attentional expertise modulate the distribution of the attentional resources in the visual space differently than nonexperienced subjects. Skilled practice may lead to minimizing attentional costs by automatizing the use of a span of attention that is adapted to the most frequent task demands and endogenously increases the allocation of resources to cope with less usual attending conditions.

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