Structure Of Distribution Network Research Articles

Research on Cable Loss Management and Loss Reduction Measures of 10kV Distribution Network

This paper discusses the importance of power supply companies to strengthen cable loss management for distribution networks of 10kV and below under the new power consumption situation. By analyzing the composition of cable losses, technical cable loss, management cable loss and assessment In terms of management, etc., analyze the factors affecting cable loss and corresponding countermeasures. In terms of technical cable loss, the influence of 10kV distribution network structure and transmission and distribution equipment, energy metering device, reactive power, voltage and other factors on distribution network cable loss and countermeasures are analyzed. In the aspect of managing cable loss, the effects of factors such as quality of copying, energy metering, anti-stealing, and operation of distribution network on distribution cable loss are analyzed. From the perspective of assessment management, the establishment of the distribution network cable loss assessment management system, the implementation of the sub-pressure distribution sub-area assessment, cable loss indicator management, etc. were discussed.

Determining the number of redundant elements of the distribution network in compliance with the specified amount of information entropy

A mathematical economic model for searching an optimal solution is proposed. In addition, a measure of information uncertainty is proposed to solve the problem the construction of a distribution network structure with the redundancy. In the model, there is an objective function for searching minimum costs and the equations for determining an information entropy of operable and non-operable states of the distribution network. The equations are based on the approaches of Ralph Hartley and Claude Shannon for entropy determination. An important place in the mathematical model is the process of constructing of a constraint function to search an optimal solution. The right part of constraints is entropy, its value reflects requirements to provide the required reliability level of power supply of the consumer. The left part is used to determine the connection entropy between an energy source and the consumer. An example of determining the number of redundant elements is offered.

Research on optimization of distribution network communication network structure based on invulnerability optimization model

In order to improve the power supply reliability and economy of the distribution network, from the perspective of optimizing its network structure and connectivity, an invulnerability optimization model based on the shortest path multi-scenario and multi-objective is constructed. For the normal operation and various single post-fault scenarios, aiming at the strong destructive and unloading or the minimum load shedding respectively, through the branch exchange method, find the best anti-destructive power of the completed distribution network in each scenario. The network topology provides a new research idea for the optimization of the network structure of medium voltage distribution network. Invulnerability measure index S(G)=1, the strongest invulnerability, the invulnerability measure index of any non-fully connected network is 0<s(G)<1, the larger S(G) is, the more compact the network structure is and the more resistant it is. The optimization results based on the approximate network example of the IEEE33 node distribution network test system show the rationality and practicability of the research method.

Reliability evaluation method for AC/DC hybrid distribution power network considering cascaded multiport power electronic transformer

With the advantage of high-power supply capacity, low loss in power transmission and distribution process, strong power flow control ability, direct current (DC) distribution network has been one hotspot of the future distribution network. The cascaded multiport power electronic transformer (PET) has been proposed as key equipment for future distribution grid with multi-voltage level and alternating current (AC)/DC hybrid feature. Based on the typical topological structure and engineering reliability theory, a reliability evaluation model for PET considering the device redundancy is established. After that, the reliability evaluation method of the AC/DC hybrid distribution network with a cascaded multiport PET is proposed. Finally, case studies are provided in a ‘hand in hand’ AC/DC hybrid power distribution network structure. Case 1 analyses the PET reliability level under different design patterns and the redundancy level. Case 2 gives the reliability evaluation results of the AC/DC hybrid distribution network with PETs, which proves the correctness and validity of the proposed algorithm. Case 3 compares the reliability level of the AC and DC system under different scenarios and proposes the reliability promotion advice for the DC power distribution network.

Research on Single-Phase Grounding Fault Location Technology

In view of the complex structure, large scale and high failure rate of distribution network, as well as many branch lines, large transition resistance, difficult to detect fault signals and difficult to locate accurately., A single-phase grounding fault location method based on single-terminal measurement for distribution network with multi-dominant transmission lines is proposed. This method can solve the problem of reliable monitoring of small current grounding fault through data processing and analysis of measuring units installed at substation equipment and line end, find grounding fault line in time, find fault point, and adopt corresponding treatment measures to block the impact scope of user branch line accident, restore the power supply of non-fault line as soon as possible, and reduce the outage time. Providing further reliable power supply fundamentally solves the problems of reliability and safety of power supply in distribution network. This method only needs to synchronously measure the voltage and current at each end of the line when the parameters of the line are known. The method is simple and the measurement accuracy is high. By locating the single-phase-to-ground fault of multi-dominant power lines, the results show that the method is correct and accurate.

Load forecasting of distribution equipment based on artificial neural network

Distribution network is the key link that affects the level of power supply service. In order to realize first-class modern distribution network and ensure the high quality electric power for residents, it is necessary to change the original working mode of operation and maintenance “passive repair” and the investment mode”treating the symptoms and not the disease” in distribution network. In such a huge distribution network structure, in order to achieve active maintenance and accurate investment construction, load forecasting of distribution network transformers scientifically will play a vital role. This paper proposes a method that realized the reasonable prediction of load in distribution network by using the self-learning and prediction function of artificial neural network and combing with the change characteristics of the load, which has important reference value to guide the construction investment and operation and maintenance of distribution network.

A Compact EBG Structure With Etching Spiral Slots for Ultrawideband Simultaneous Switching Noise Mitigation in Mixed Signal Systems

In this paper, a compact electromagnetic bandgap (EBG) structure for mitigating simultaneous switching noise (SSN) in high-speed mixed signal systems is proposed. Only one spiral slot is etched on the square patch, which constitutes the unit cell of the presented EBG pattern. The equivalent circuit model is developed to interpret the mechanism of the proposed power distribution network structure. By etching slot in the square patch of the EBG pattern, a high impedance is provided for prohibiting the SSN propagation. Furthermore, the capacitance is increased correspondingly, which can enlarge the bandwidth of the SSN suppression performance. An ultrawideband SSN suppression property is achieved from 0.35 to 20 GHz under the suppression level of −40 dB. In comparison with the traditional multiturns spiral EBG structure, not only the bandwidth but also the rejection level can be improved significantly with the presented design. Moreover, the SI performance is investigated, and the corresponding improvement measure is presented. Good agreements are observed between the simulation and measured results.

A combined spatial and technological model for the planning of district energy systems

This paper describes a combined spatial and technological model for planning district energy systems. The model is formulated as a mixed integer linear program (MILP) and selects the optimal mix of technology types, sizes and fuels for local energy generation, combined with energy imports as required, and exports of any excess energy. The model can also be used to select the locations for the energy sources, the distribution route, and optionally, to select the heat loads that will be connected to a district energy system. The optimisation model combines a map-based spatial framework, describing the potential distribution network structure, with a flexible Resource Technology Network (RTN) representation which incorporates multiple heat sources. Scenarios can be formed for different price levels for delivered heat or electricity, combined heat and electricity demands, and different technologies and fuels for heat generation. Results for scenarios based on a synthesized test dataset are presented. The results illustrate how the model may be integrated within a map-based decision support tool for urban planners. The paper also introduces a system value metric to quantify the incremental impact of investments in the heat network.

Research on Electrical Automation Control System and Design Based on Geographic Information Technology

As the pace of power plant construction accelerates, higher requirements are placed on the application performance of the control system. From the current development status of the current electrical control system, it reflects the characteristics of multi-function, miniaturization and intelligence, and provides an important guarantee for the reliable operation of the electrical system. This paper analyzes and studies GIS in geographic information technology and power system application. The structure and function of electric power GIS system are designed. According to the structure and particularity of distribution network, a new distribution network database model is established. The overall planning and design of the network information database are carried out. The design idea of electric automation control system is discussed, and the development trend of electric automation control system in the future is prospected.

Scheduling Post-Disaster Repairs in Electricity Distribution Networks

Natural disasters, such as hurricanes, earthquakes, and large wind or ice storms, typically cause damages to a large number of components in electricity distribution networks. Since power cannot be restored until these damages are repaired, strategically scheduling the repairs by available crews could reduce the harm done to the affected community. Considering the radial structure of many distribution networks, we model this repair and restoration process as a scheduling problem with soft precedence constraints. As a benchmark, we first formulate this problem as a time-indexed integer linear program (LP) with valid inequalities. Three approximation algorithms with performance guarantees are then proposed to solve this problem: first, an LP-based list scheduling algorithm, second, a single to multi-crew repair schedule conversion algorithm, and third, a dispatch rule based on $\rho$ -factors which can be interpreted as component importance measures. Numerical results validate the effectiveness of the proposed methods.

Optimization of Distribution Network Construction Based on GIS System

With the rapid development of China’s economy and science and technology, people’s daily life and scientific research work demand more and more electricity. The traditional distribution network structure and load can hardly meet the actual demand. Therefore, it is very necessary to construct a more stable distribution network system in accordance with the actual demand for electricity. This paper mainly introduces the application of GIS system in power distribution network planning and design, and realizes the optimization and upgrading of power distribution network in coordination with the geographic information of the construction site, so as to meet the increasing demand for electricity.

Distributed Topology Identification Information Model of Distribution Network Based on IEC61850

This paper proposes a distributed topology information model based on IEC61850 to support the distributed topology processing function of the distribution network automation system. The information model expands the new logical nodes and common data classes for storing local topology information of local subgraphs and communication information of adjacent intelligent electronic devices. By using the distributed adaptation of graph connectivity algorithm and the extended IEC61850 information model, the dynamic topology identification function of the distribution network structure is realized. The extended information model and topology recognition algorithm are verified by the cyber-physical simulation system.

A New Distribution Network Structure for Maximizing the Allowable Penetration of Distributed Energy Resource

The traditional network structure cannot be suitable for the connection of large-scale distributed energy resources, thus the high penetration of distributed energy resource (DER) will have destructive effects on the security and reliability of the traditional distribution network. The paper proposes a new distribution network structure to increase the maximum allowable penetration of DER. Firstly, the model and method of the new distribution network structure are presented. Secondly, the theory basis of increasing the DER penetration by the new network structure is proved. Finally, the proposed model and method are applied to the typical test case. And the simulation results show that compared with the traditional structure, the new distribution network structure can not only increase the maximum penetration of distributed energy resource greatly, but also realize the high energy efficiency, reliability and sustainability. Therefore, the issue of future distribution network security with high penetration of distributed energy resource can be well solved by the new distribution network structure proposed in the paper.

Analysis and Suggestion on Neutral Grounding Mode for Shanghai Distribution Network Considering Power Supply Reliability

The demand for reliable power supply in large cities is the major concern for both consumers and company, and power outages have uprising influence on economic losses and social impacts. With the continuing growth of underground cable ratio in Shanghai, the medium-voltage distribution network structures are experiencing changes. The choice of grounding method has considerable impact on operation safety and system reliability. It is crucial to carry out in-depth and systematic analysis on different grounding modes. This paper analyzes the technical route, insulation coordination, protection configuration and system reliability for neutral grounding mode for Shanghai distribution network with regard to the development status and safety requirements of urban medium voltage distribution grid, providing effective technical principles and engineering proposals for system planning and safe operation.

Coordinated Optimal Network Reconfiguration and Voltage Regulator/DER Control for Unbalanced Distribution Systems

Network reconfiguration has long been used by distribution system operators to achieve certain operation objectives such as reducing system losses or regulating bus voltages. In emerging distribution systems with a proliferation of distributed energy resources (DERs), co-optimizing network topology and DERs’ dispatches could further enhance such operational benefits. This paper focuses on the optimal network reconfiguration problem of distribution systems via an unbalanced ac optimal power flow framework, which rigorously addresses operation characters of unbalanced network, DERs, and voltage regulators (VRs). Two VR models with continuous and discrete tap ratios are studied and compared. The proposed co-optimization problem is formulated as a mixed-integer chordal relaxation-based semidefinite programming model with binary variables indicating line-switching statuses and tap positions. Several acceleration strategies by studying the structure of distribution networks are explored for reducing the number of binary variables and enhancing the computational performance. Case studies on modified IEEE 34-bus and 392-bus systems illustrate the effectiveness of the proposed approach.

Power-mileage-based Algorithm for the Optimization of Distribution Network Structures via Adding Transmission Lines

In remote areas, large power stations are often installed to supply local loads due to the difficulties of power transmission. However, with the development of renewable energies and poverty alleviation programs, many renewable energy stations have been installed in such areas. This large amount of surplus and fluctuating energy causes a poor voltage quality, and this problem is difficult to solve with traditional methods. Adding transmission lines can be a feasible solution, but the related research is limited. To provide a guideline for this solution, a network optimization algorithm is proposed in this paper. In the process, a sub-grid that is far from the national grid with an imbalanced power supply and demand is connected to the national grid directly to improve the power quality. First, the linear performance index power mileage is defined to facilitate the calculation and help denote the voltage quality. Then, an iterative algorithm is formed to perform the network optimization and automatically choose the number of clusters. A case study of an actual power grid in Chongqing, China, and an IEEE 123-bus case are used to verify our algorithm. The results show there is a great improvement in the voltage profile.

Research on Prediction Model of Line Loss Rate in Transformer District Based on LM Numerical Optimization and BP Neural Network

Due to the complex network structure of the low-voltage distribution network, the backwardness of electrical equipment and the large number of nodes, it is difficult to calculate the line loss rate accurately. The author established a simple linear loss rate prediction model with higher accuracy. Firstly, according to the actual power operation data, the typical characteristic parameters with great influence are obtained. Secondly, the K-means clustering algorithm is applied to classify each transformer district according to the different power consumption characteristics. Finally, the BP neural network model based on LM numerical optimization algorithm is designed and applied to predict line loss rate for data class of each transformer district. 1026 transformer district with complete power operation data in a region was selected as an example to verify the accuracy of the proposed prediction method, which provides data and theoretical basis for the loss reduction measures.

Impact Assessment of Distribution Network Layout on the Reliability of Water Delivery

The process of shaping distribution network structures is one of the most fundamental design tasks, and determines the delivery certainty of media transported by them. It is especially crucial with reference to network elements of a critical character, such as roads or water supply, sewage, or electrical networks. In urban conditions, the geometric shaping of these structures has a quasi-chaotic character that is individual for each network and city. The complexity of these networks increases significantly with the size of a city, and therefore the evaluation of water delivery certainty is also a difficult issue. Despite many years of research, there is no universal method to evaluate this certainty. The objective of this paper is to present two original approaches: the number of minimal efficiency paths from a water source to reference consumption nodes, and the relation of this number to the fractal dimension of a network’s geometric structure. The developed methods were tested in the conditions of a few real water supply networks. The obtained results indicate that the analyzed methods can be used for the preliminary and relatively rapid evaluation of water delivery certainty.

Research and Simulation of IBPSO-based Fault Location in Power Distribution Network adopting DG

By analyzing the system structure of power distribution network, the paper summarizes the defects suffered by traditional binary particle swarm optimization (BPSO) and studies the application of improved BPSO (IBPSO) in fault location in power distribution network adopting distributed generation (DG). The standard BPSO is improved by introducing compression factor and Linearly Decreasing Inertia Weight (LDIW), which achieves the improvement on the convergence and fault tolerance. Also, with the application of the new algorithm in new field, the coding mode in DG power distribution network is improved and optimized. Simulation experiment is performed to rationally validate the feasibility of the new algorithm and gains the satisfactory results, which provides better technical space for system management of power distribution network as well as achieves the popularization and promotion of DG power distribution network in modern society.

Choice of PV's Favorable Constant Leading Power Factor Considering Temporary Structure and Metamorphosis of Distribution Network

Choice of PV's Favorable Constant Leading Power Factor Considering Temporary Structure and Metamorphosis of Distribution Network