scholarly journals Reliability cost/worth assessment of distribution network formed by underground cables and overhead lines. Case study of Latvia

Energetika ◽  
2015 ◽  
Vol 61 (1) ◽  
Author(s):  
Aleksandrs Ļvovs ◽  
Ilze Priedite
Keyword(s):  
Power Supply ◽  
Distribution Network ◽  
Distribution Networks ◽  
Actual Distribution ◽  
Underground Cables ◽  
Overhead Lines ◽  
Capital Costs ◽  
Reliability Level ◽  
Fault Statistics

The increasing number of severe weather occurrences that influence the number of large scale outages, especially in rural distribution networks, makes the question on the need of increasing reliability level of power supply of the distribution network even more actual. Distribution system operators and national regulators shall not only find a reliable but also a cost-effective solution for further distribution network development: the optimal reliability level of power supply. One of the reliability improvement solutions that allows effectively dealing with the reduction of the number of outages in rural distribution networks is the cablification of network. Construction costs of the aforementioned solution are quite high in comparison to other network line types, and due to that, the implementation of the solution always raises discussions on cost-effectiveness. The paper presents approaches for the cost/worth assessment of power line lifetime costs in the distribution network and for the assessment of customer costs of reliability that takes into account time-varying loads and outage costs (previously developed by authors of this paper [6, 7]) as well as for the assessment of traders’ losses due to electrical energy not supplied. The case study included in the paper is performed for Latvian conditions and takes into account information on the real customer costs of reliability of Latvian customers (information from the study of the Institute of Physical Energetics), fault statistics of Latvian underground cables and overhead lines, information with a high level of details on the capital costs, operational and fault elimination costs of distribution lines in Latvia.

Influence of distributed power supply in distributed power distribution network

2021 ◽  
pp. 1-8
Author(s):  
Xin Shen ◽  
Hongchun Shu ◽  
Min Cao ◽  
Nan Pan ◽  
Junbin Qian
Keyword(s):  
Power Supply ◽  
Power Distribution ◽  
Short Circuit ◽  
Power Grid ◽  
Distribution Network ◽  
Distribution Networks ◽  
Power Supplies ◽  
Power Distribution Network ◽  
Power Sources ◽  
Distributed Power

In distribution networks with distributed power supplies, distributed power supplies can also be used as backup power sources to support the grid. If a distribution network contains multiple distributed power sources, the distribution network becomes a complex power grid with multiple power supplies. When a short-circuit fault occurs at a certain point on the power distribution network, the size, direction and duration of the short-circuit current are no longer single due to the existence of distributed power, and will vary with the location and capacity of the distributed power supply system. The change, in turn, affects the current in the grid, resulting in the generation and propagation of additional current. This power grid of power electronics will cause problems such as excessive standard mis-operation, abnormal heating of the converter and component burnout, and communication system failure. It is of great and practical significance to study the influence of distributed power in distributed power distribution networks.

SERVICEABILITY OF NATURAL GAS DISTRIBUTION NETWORKS AFTER EARTHQUAKES

2013 ◽  
Vol 07 (02) ◽  
pp. 1350005 ◽  
Author(s):  
GIAN PAOLO CIMELLARO ◽  
ALESSANDRO DE STEFANO ◽  
OMAR VILLA
Keyword(s):  
Natural Gas ◽  
Distribution Network ◽  
Distribution Networks ◽  
Small Towns ◽  
Disaster Resilience ◽  
Gas Distribution ◽  
Gas Network ◽  
Resilience Index ◽  
Entire Network

The concept of disaster resilience has received considerable attention in recent years and it is increasingly used as an approach for understanding the dynamics of natural disaster systems. No models are available in literature to measure the performance of natural gas network, therefore, in this paper, a new performance index measuring functionality of gas distribution network have been proposed to evaluate the resilience index of the entire network. It can be used for any type of natural or manmade hazard which might lead to the disruption of the system. The gas distribution network of the municipalities of Introdacqua and Sulmona, two small towns in the center of Italy which were affected by 2009 earthquake have been used as case study. Together the pipeline network covers an area of 136 km2, with 3 M/R stations and 16 regulation groups. The software SynerGEE has been used to simulate different scenario events. The numerical results showed that, during emergency, to ensure an acceptable delivery service, it is crucial to guarantee the functionality of the medium pressure gas distribution network. Instead to improve resilience of the entire network the best retrofit strategy is to include emergency shutoff valves along the pipes.

scholarly journals Research and Application of a Clear Diamond-Shaped Distribution Network Structure

2021 ◽  
Vol 9 ◽  
Author(s):  
Liu Shengli ◽  
Wu Jun ◽  
Xue Longjiang ◽  
Wu Di ◽  
Lu Haiqing ◽  
...  
Keyword(s):  
Network Structure ◽  
Power Supply ◽  
Distribution Network ◽  
Regional Distribution ◽  
Distribution Networks ◽  
Ring Network ◽  
Medium Voltage ◽  
Double Ring ◽  
Diamond Type ◽  
Supply Reliability

Aiming at the problems of low power supply reliability, poor transfer capacity between stations, and low line utilization in the current distribution network, this paper proposes a diamond-shaped distribution network structure with a clear structure. First, we investigated the typical wiring patterns of medium-voltage distribution networks in Tokyo, Japan, Paris, France, and China’s developed cities, and summarized experience and shortcomings. Secondly, combining the typical wiring patterns of distribution networks in China and abroad, construct a diamond-shaped distribution network structure, and study its adaptability, safety and flexibility, power supply reliability, and economy. Finally, take the transformation of the wiring mode of a regional distribution network in a certain city as an example, compare the use of the diamond-shaped distribution network structure in this article with the use of cable double-ring network wiring, cable “double petal” wiring, and Shanghai diamond-type wiring distribution network grid reconstruction The effect verifies the superiority of the diamond-shaped distribution network structure in this paper.

scholarly journals An Effective Method to Calculate Frequency Response of Distribution Networks for PLC Applications

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 649 ◽  
Author(s):  
Hongshan Zhao ◽  
Weitao Zhang ◽  
Yan Wang
Keyword(s):  
Frequency Response ◽  
Distribution Networks ◽  
Dynamic Changes ◽  
Binary Function ◽  
Underground Cables ◽  
Overhead Lines ◽  
Medium Voltage ◽  
Response Characteristics ◽  
Network Topologies ◽  
Propagation Matrix

Modelling and estimating power-line communication (PLC) channels are complicated issues due to the complex network topologies, various junctions, and changeable loads. This paper focuses on the frequency response characteristics (FRCs) of medium-voltage (MV) PLC networks with special consideration of two scenarios that are often neglected but generally exist. In the first scenario, the MV distribution network is of the ring topology. In the second scenario, the MV overhead lines and underground cables join at junctions, and the shields of underground cables are grounded with nonzero grounding impedances at the junctions. These conditions lead to the failure of currently popular methods to different degrees. For this reason, we developed an effective method to calculate the FRCs of distribution networks for PLC applications. With this method, the frequency responses of nodes are simply expressed as the binary function of the overall tube propagation matrix and overall node scattering matrix, which is convenient for calculations and analyses. The proposed method was validated by the agreement between the calculated and measured FRCs. The results of two test examples showed that the proposed method performed better in comparison with the traditional approximate method when nonideal grounding conditions were taken into account. The proposed method is also independent of the network topology, so it can adapt to the dynamic changes of the network structure.

scholarly journals Research on Optimization of Port Container Inland Collection and Distribution Network

2020 ◽  
Vol 165 ◽  
pp. 06024
Author(s):  
Xuan Wang ◽  
Yun Jing
Keyword(s):  
Distribution Network ◽  
Distribution Networks ◽  
Development Strategies ◽  
Optimal Model ◽  
Matlab Software ◽  
Belt And Road ◽  
Network Costs ◽  
The Belt And Road

With the advancement of country’s “the Belt and Road” strategy, each port is actively formulating development strategies to help implement the strategy. The port inland collection and distribution network is an important guarantee for the development of the port, and it is a key component to promote the connection between the port and the inland hinterland. It has an important role in expanding the scale of the port and improving the overall competitiveness of the port. Aiming at the current imbalance of the collection and distribution methods and the imperfect collection and distribution networks in most ports, this paper establishes an optimal model of collection and distribution network costs and quantitatively optimizes the collection and distribution network corridors. The Tianjin Port is selected as a case study object. And the MATLAB software is used to solve the analysis. The conclusion is that Tianjin Port could alleviate the pressure of the collection and distribution network by increasing the density of container trains with the hinterland cities, which verified the validity of the model.

Optimal overcurrent relay coordination in distribution network based on Lightning Flash Algorithm

2018 ◽  
Vol 35 (3) ◽  
pp. 1140-1160 ◽  
Author(s):  
Mostafa Kheshti ◽  
Xiaoning Kang
Keyword(s):  
Distribution System ◽  
Distribution Network ◽  
Distribution Networks ◽  
Lightning Flash ◽  
Content Type ◽  
Lightning Strikes ◽  
Relay Coordination ◽  
Cloud To Ground Lightning ◽  
Practical Implications

Purpose Distribution network protection is a complicated problem and mal-operation of the protective relays due to false settings make the operation of the network unreliable. Besides, obtaining proper settings could be very complicated. This paper aims to discuss an innovative evolutionary Lightning Flash Algorithm (LFA) which is developed for solving the relay coordination problems in distribution networks. The proposed method is inspired from the movements of cloud to ground lightning strikes in a thunderstorm phenomenon. LFA is applied on three case study systems including ring, interconnected and radial distribution networks. The power flow analysis is performed in Digsilent Power Factory software; then the collected data are sent to MATLAB software for optimization process. The proposed algorithm provides optimum time multiplier setting and plug setting of all digital overcurrent relays in each system. The results are compared with other methods such as particle swarm optimization and genetic algorithm. The result comparisons demonstrate that the proposed LFA can successfully obtain proper relay settings in distribution networks with faster speed of convergence and lower total operation time of relays. Also, it shows the superiority and effectiveness of this method against other algorithms. Design/methodology/approach A novel LFA is designed based on the movements of cloud to ground lightning strikes in a thunderstorm. This method is used to optimally adjust the time multiplier setting and plug setting of the relays in distribution system to provide a proper coordination scheme. Findings The proposed algorithm was tested on three case study systems, and the results were compared with other methods. The results confirmed that the proposed method could optimally adjust the relay settings in the electric distribution system to provide a proper protection scheme. Practical implications The practical implications can be conducted on distribution networks. The studies provided in this paper approve the practical application of the proposed method in providing proper relay protection in real power system. Originality/value This paper proposes a new evolutionary method derived from the movements of cloud to ground lightning strikes in thunderstorm. The proposed method can be used as an optimization toolbox to solve complex optimization problems in practical engineering systems.

scholarly journals Technical note: Graph theory-based heuristics to aid in the implementation of optimized drinking water network sectorization

2022 ◽  
Author(s):  
Marius Møller Rokstad ◽  
Karel Antonie van Laarhoven
Keyword(s):  
Drinking Water ◽  
Water Distribution ◽  
Mathematical Problem ◽  
Distribution Network ◽  
Large City ◽  
Distribution Networks ◽  
Technical Note ◽  
Optimization Techniques ◽  
Actual Distribution ◽  
Drinking Water Distribution

Abstract. Drinking water distribution networks form an essential part of modern-day critical infrastructure. Sectorizing a network into district metered areas is a key technique for pressure management and water loss reduction. Sectorizing an existing network from scratch is, however, an exceedingly complex design task that designs in a well-studied general mathematical problem. Numerical optimization techniques such as evolutionary algorithms can be used to search for near-optimal solutions to such problems, but doing so within a reasonable timeframe remains an ongoing challenge. In this work, we introduce two heuristic tricks that use information of the network structure and information of the operational requirements of the drinking water distribution network to modify the basic evolutionary algorithm used to solve the general problem. These techniques not only reduce the time required to find good solutions, but also ensure that these solutions better match the requirements of drinking water practice. Both techniques were demonstrated by applying them in the sectorization of the actual distribution network of a large city.

scholarly journals Active Distribution Network Modeling for Enhancing Sustainable Power System Performance; a Case Study in Egypt

2020 ◽  
Vol 12 (21) ◽  
pp. 8991
Author(s):  
Ali A. Radwan ◽  
Ahmed A. Zaki Diab ◽  
Abo-Hashima M. Elsayed ◽  
Hassan Haes Alhelou ◽  
Pierluigi Siano
Keyword(s):  
Power Systems ◽  
Electricity Market ◽  
System Performance ◽  
Power Flow ◽  
Electrical Power ◽  
Distribution Network ◽  
Distribution Networks ◽  
Western Desert ◽  
Distribution Transformers

The remarkable growth of distributed generation (DG) penetration inside electrical power systems turns the familiar passive distribution networks (PDNs) into active distribution networks (ADNs). Based on the backward/forward sweep method (BFS), a new power-flow algorithm was developed in this paper. The algorithm is flexible to handle the bidirectional flow of power that characterizes the modern ADNs. Models of the commonly used distribution network components were integrated with the developed algorithm to form a comprehensive tool. This tool is valid for modeling either balanced or unbalanced ADNs with an unlimited number of nodes or laterals. The integrated models involve modeling of distribution lines, losses inside distribution transformers, automatic voltage regulators (AVRs), DG units, shunt capacitor banks (SCBs) and different load models. To verify its validity, the presented algorithm was first applied to the unbalanced IEEE 37-node standard feeder in both passive and active states. Moreover, the algorithm was then applied to a balanced 22 kV real distribution network as a case study. The selected network is located in a remote area in the western desert of Upper Egypt, far away from the Egyptian unified national grid. Accordingly, the paper examines the current and future situation of the Egyptian electricity market. Comparison studies between the performance of the proposed ADNs and the classical PDNs are discussed. Simulation results are presented to demonstrate the effectiveness of the proposed ADNs in preserving the network assets, improving the system performance and minimizing the power losses.

Research of Fault Location in Low-Voltage Distribution Networks

2013 ◽  
Vol 340 ◽  
pp. 819-823
Author(s):  
Yu Jun Zhang ◽  
Jing Li
Keyword(s):  
Fault Location ◽  
Low Voltage ◽  
Short Circuit ◽  
Distribution Network ◽  
Distribution Networks ◽  
Structural Features ◽  
Voltage Distribution ◽  
Short Supply ◽  
Actual Distribution ◽  
Network Fault

The low-voltage distribution networks have some structural features, such as short supply line, more lines branch and influence of transition resistance of the short-circuit current. These characteristics seriously affect the development of fault location technology. The paper, based on the basis of the structural features about the low-voltage distribution networks, create the distribution networks of description matrix by knowledge of mathematical topology and use the distribution network fault location algorithm based on web-based structure matrix. By the algorithm, the area of fault judgment and the actual distribution network fault location are fully consistent. The new theory provides a new way of thinking for fault location in low-voltage distribution networks.

scholarly journals Substantiation of the choice of the replacement scheme of line for mathematical modeling of 20 kV power supplies.

2021 ◽  
Vol 24 (1) ◽  
pp. 69-72
Author(s):  
SKRYPNYK S. ◽  
Keyword(s):  
Power Systems ◽  
Transmission Lines ◽  
Power Supply ◽  
Electrical Equipment ◽  
Distribution Networks ◽  
Power Line ◽  
Power Lines ◽  
Electrical Networks ◽  
Overhead Lines ◽  
Replacement Scheme

In the current global economic crisis and acute shortage of energy resources, increasing importance is attached to energy saving measures, economical and careful consumption of raw materials, materials, electricity and heat, environmental safety of industrial production. During the reconstruction of existing power supply systems of industrial enterprises, modern progressive solutions should be considered and implemented, morally and physically obsolete electrical equipment should be replaced, namely the introduction of new electrical equipment for transition from 6/10 kV to 20 kV in Ukrainian power systems. It is also necessary to pay attention to the improvement of power supply circuits and distribution networks, the implementation of complex automation of complex technological processes, rational compensation of reactive power at all levels of power supply systems. In the power system, the main transport link is the power line. Power lines (transmission lines) are long conductors suspended at a safe distance from the ground overhead lines (overhead lines) or cable lines (overhead lines) in which conductors are insulated from each other and from the environment and protected by insulation and armor electricity. Power lines are the most massive elements of the power supply system, they connect the individual nodes of its circuit. Longitudinal and transverse parameters are distinguished in alternative schemes. The load current flows through the longitudinal parameters, voltage is applied to the transverse ones. The replacement circuit of the electrical network consists of replacement circuits of the following elements: power lines, transformers, reactors, capacitors, loads, power sources. Calculating the steady-state modes of power systems, the substitution schemes of the elements are given in a single-line design, because the parameters of all phases are symmetrical. In local and local electrical networks with a relatively short length and low rated voltage, the conduction currents are small compared to load currents. Therefore, in typical electrical calculations of these networks, the capacitive conductivity of the lines is not taken into account. However, for these networks, the accounting of capacitive conductivities is necessary when considering some modes, the existence of which in itself is due only to the presence of capacitive conductivities. For example, the mode of single-phase ground fault in a network with isolated or compensated neutral or analysis of the modes of operation of neutrals of electrical networks of different voltage classes cannot be performed without taking into account the capacitive conductivity of these networks. When switching the power system of Ukraine to the nominal voltage of 20 kV, it should be taken into account that the transmission line will be replaced in the sections of both the overhead power line and cable power line, namely 35, 10, 6 kV. The replacement scheme must describe all the characteristics and properties of the elements of cable and overhead lines in accordance with real conditions. Thus, it is not expedient to use simplified substitution circuits that neglect energy parameters and properties of conductors to study the parameters of transmission lines. The use of a complete "P" -shaped scheme for the analysis of the parameters of transmission lines and transmission lines for a voltage of 20 kV is the basis of mathematical modeling of the transmission system in the distribution networks of our country.

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