Distribution Network Feeder Research Articles

A fault detection method in asymmetric networks based on the zero-sequence current

Abstract There is always zero-sequence current in the MV network because of its asymmetric parameters of transmission lines. Therefore, studying the distribution characteristics of natural unbalanced current through the feeder of an asymmetric distribution network is conducive to the feeder selection. In this paper, the expression of the current of each feeder is derived and its composition and distribution characteristics are analyzed. Based on this, the steady-state model of the feeder is constructed. To eliminate the effects of natural unbalanced current, it is proposed to subtract the current before and after a fault occurrence, and subsequently identify the faulted line according to phase-angle characteristics of the resulting zero-sequence current increment. Finally, a MATLAB/Simulink simulation system is constructed and employed for verification purposes.

A novel PQ improvement in multi-parallel feeder distribution system using multi-convertible UPQC device

In the current situation, the use of non-linear power electronic devices in automated industries, arc-furnaces, and adjustable speed drives. The nature of large-sized non-linear loads causes harmonic pollution, voltage interruptions, and voltage sag/swell issues, which are the main issues in modern multi-parallel feeder distribution network. Several mitigation techniques among the above, the multi-convertible universal power-quality conditioner has reliable performance, robust operation and also mitigation of both current-voltage allied power quality (PQ) issues accordingly. The multi-convertible universal power-quality conditioner (Mcon-UPQC) device mitigates power-quality issues by extracting deviated supply voltage and distorted load current by using feasible control algorithm. But, the computational delay, complex mathematical transformation and response delay are the major problem identified in conventional control algorithms. In this work, a novel generalized vector reference control algorithm has been proposed for extraction of fundamental reference voltage-current signals. The performance and effectiveness of proposed control algorithm of Mcon-UPQC device is validated by using MATLAB-Simulink computing tool, simulated outcomes are illustrated with valid comparisons.

Automated feeder routing for underground electricity distribution networks based on aerial images

The process towards a carbon-neutral society requires a substantial amount of investment into electricity distribution networks for integrating more sustainable technologies such as photovoltaic systems, electric vehicles, heat pumps, and others. In order to execute the large number of network expansion measures associated with this effort, strategic and operational planning of distribution networks benefit from higher degrees of automation. A key component in these planning processes is the routing of feeder segments, i.e., the task of finding feasible and cost-efficient paths for underground power lines between two geographic locations, such as residential buildings and transformer stations. In this paper, we present FEEDAIR, a novel and innovative approach to automate feeder routing based exclusively on aerial images. FEEDAIR integrates deep neural networks, which encode geoinformation from aerial images, and A* search, which identifies effective feeder routes based on this encoding. We train and evaluate FEEDAIR using a large data set of more than 7000 real-world electricity distribution network feeder segments. Thereby, we compare FEEDAIR to state-of-the-art approaches from related work and find that the feeder segments generated by FEEDAIR are on par or superior with regard to several characteristics and metrics. FEEDAIR achieves this performance by relying exclusively on aerial images, whereas competing approaches require data on geocoded land cover and estimated construction cost, which is not as widely available and is frequently based on potentially subjective expert opinion.

A fault location method for distribution network feeder terminal based on SABSO algorithm

With the increasingly prominent problem of faults at the end of distribution network feeders, a fault area localization method based on simulated annealing Tianniu swarm optimization (SABSO) algorithm is proposed to address the shortcomings of traditional fault localization methods. This method achieves rapid and accurate location of fault areas by collecting and analyzing fault information at the end of the distribution network feeder. The experimental results show that this method has higher accuracy and can accurately locate the fault area at the end of the distribution network feeder, providing strong support for the safe and stable operation of the distribution network.

Time-Varying Operating Regions of End-Users and Feeders in Low-Voltage Distribution Networks

Time-Varying Operating Regions of End-Users and Feeders in Low-Voltage Distribution Networks

Feeder Capacity Planning and Reliability Evaluation Model of Distribution Network Based on Support Vector Machine

Capacity planning and reliability evaluation models of the traditional distribution network feeder mainly use multi-option balance constraints for multi-objective solutions, which are prone to capacity constraints, resulting in lower reliability indicators for planning and evaluation. Therefore, a brand-new distribution network feeder capacity planning and reliability evaluation model based on a support vector machine is designed. By using support vector machines to design the reliability evaluation process of distribution network feeder capacity planning, we establish an optimization model for reliability evaluation of distribution network feeder capacity planning. The experimental results show that the designed feeder capacity planning and reliability evaluation model based on a support vector machine has good evaluation results, high-reliability indicators for planning and evaluation, reliability, and certain application values.

Improving estimation process of technical losses in electrical distribution system considering repairing periods

Recently, few studies were presented to include the effect of repairing periods in the estimation process of technical loss of either radial or ring medium voltage feeders in distribution networks. The previously presented studies are classified into traditional methods or using deduced formulas that need repeating the calculations many times with different operating conditions, i.e., normal operating periods (NOP) or repairing time (RT). The calculations using the previous methods seem to be repetitive and, furthermore, their equations parameters have to be calculated separately for each distribution network and/or for each loading level. In this paper, an improved formula is suggested to be applied for considering the effect of repairing periods when calculating technical energy losses (TELs). The improved formula includes a new term representing the ratio of repairing hours to the total operation periods. By applying the improved formula, there will be no need for repeating load flow calculations many times for each loading condition as in the previous studies. The proposed formula is validated through applying the improved formula for IEEE-16 bus distribution system. Electrical transient and analysis program (ETAP) version 12.6 was used for a load flow analysis of the case studies.

Correlation knowledge extraction based on data mining for distribution network planning

Traditional distribution network planning relies on the professional knowledge of planners, especially when analyzing the correlations between the problems existing in the network and the crucial influencing factors. The inherent laws reflected by the historical data of the distribution network are ignored, which affects the objectivity of the planning scheme. In this study, to improve the efficiency and accuracy of distribution network planning, the characteristics of distribution network data were extracted using a data-mining technique, and correlation knowledge of existing problems in the network was obtained. A data-mining model based on correlation rules was established. The inputs of the model were the electrical characteristic indices screened using the gray correlation method. The Apriori algorithm was used to extract correlation knowledge from the operational data of the distribution network and obtain strong correlation rules. Degree of promotion and chi-square tests were used to verify the rationality of the strong correlation rules of the model output. In this study, the correlation relationship between heavy load or overload problems of distribution network feeders in different regions and related characteristic indices was determined, and the confidence of the correlation rules was obtained. These results can provide an effective basis for the formulation of a distribution network planning scheme.

A Comprehensive Review on Distributed Feeder Protection Problems in the Gaza Strip 22/0.4 kV Overhead Power Distribution System – A Case Study

This paper provides a perspective on protective system at 22kV overhead feeders in Gaza distribution network using symmetrical components method and ETAP software. Electrical disturbances from high rate of outage feeders at the 22 kV overhead power lines frequently cause disruptions on the generating plant and customer loads. One sub-transmission feeder from a parallel set of ten 22 KV feeders (140 MW) in the Gaza west substation is selected as a case study in this research. Because the protection system lacks a data fault recorder (DFR), the paper calculates the fault currents at both the nearest substation bus and the last bus in the distributed feeder using the symmetrical components method and verifies the results by using ETAP software simulation. The results from calculating the minimum fault at the last bus indicated that the current protective parameters are reasonable and satisfied for detecting and interrupting the occurring faults. This author paper proposes increasing the fault clearing time at farthest feeder bus to make protective functions less sensitive by adjusting TMS to 0.08 for time overcurrent and earth fault and setting pickup level to 3.8 for instantaneously overcurrent. The design model is run on the selected feeder, and simulation results guarantee the proposed model's accurate performance for both overcurrent and earth faults after changing the fault clearing time. There will be no miscoordination of protective devices or operational risks while running the design model for the selected feeder with new settings. Gaza's distribution feeder network requires structural improvements to become more reliable and to reduce the high rate of feeder trip, and practical recommendations to improve current installation distribution grid are included in this paper.

Research on distribution network optimal operation with a novel medium voltage photovoltaic power generation device with the soft open point function

Soft open point (SOP) realizes the normal and flexible interconnection between distribution network feeders, leading to the improvement of the flexibility and rapidity of the distribution network control. However, drawbacks such as high cost and low utilization rate limit its application. A novel medium voltage photovoltaic power generation device with the SOP function is proposed in this paper. There are two grid-connected interfaces, and both of them adopt the cascaded H-bridge topology. A common DC-link is used for both H-bridge inverters belonging to the two grid-connected interfaces respectively. The proposed device eliminates the step-up transformers, and can be connected directly to the medium voltage distribution network. Therefore, advantages such as simple structure, low cost, low power loss and fault-tolerant operation capability are able to be obtained. The stability and flexibility of the distribution network operation are improved. The topology and power flow mode of the proposed medium voltage photovoltaic power generation device with the SOP function are analyzed, and the distribution network multi-objective optimal operation model with the proposed device is established. The proposed medium voltage photovoltaic power generation device with the SOP function is connected to the modified IEEE 33-node distribution network, and the network optimal operation with the device in terms of the power flow optimization and voltage improvement is analyzed.

Analysis of current protection in distribution networks with clean energy access

With the rapid development of the new energy industry, distributed generation (DG) is connected to the power grid on a large scale, and the traditional relay protection scheme is no longer suitable for modern power systems. In order to solve this problem, this paper establishes a mathematical model of the equivalent circuit of distributed photovoltaic power supply according to the external characteristics of photovoltaic cells, and analyzes its volt-ampmeter characteristics and voltage output characteristics of power supply. On this basis, it analyzes and puts forward the control mode of DG when the distribution network is faulty. On the basis of the study, this article has double feeder distribution network as an example, the analysis when the line fault occurring at different extents of DG connected to different position on the influence of the distribution network current protection, the results show that when answering DG side in the feeder bus for distribution network of current protection, pick a smaller effect on both ends of feeder, has a certain symmetry. Finally, the accuracy of theoretical analysis is verified by establishing a simulation model in PSCAD.

Research on voltage and power control strategy of distribution network

ABSTRACT Traditional central control system is unable to deal with the optimal control tasks of modern distribution networks due to its low reliability, high computation and communication burden and poor expansibility. Based on distributed collaboration principle, this paper presents a multiple-object distributed optimisation control strategy for distribution network utilising DG grouping method. Distributed control strategy for node voltage control group is developed by taking the capacity utilisation ratio (CUR) of DG as the consensus variable, to comply with the feature of high resistance/reactance ratio of distribution network feeder line. Distributed control strategies for exchanged power control groups, which respectively takes CUR and power factor as the consensus variable, are formulated according to the different conditions of exchanged power imbalance. The parameter tuning method for three kinds of distributed optimisation control strategies are presented. The correctness and effectiveness of the proposed method are verified by simulation examples in the IEEE 14-node system, and simulation results on the IEEE 33-node test system are presented to show the robustness of the method to the disturbances related with distributed generation.

A real-time three-phase line loss calculation method for distribution network based on feeder terminal unit

Combined with the monitoring data of the new distribution network Feeder Terminal Unit (FTU), an innovative three-phase real-time line loss calculation method based on the feeder segment rather than the entire feeder as the basic calculation unit is proposed. This method uses the variable structure dissipative network theory, divides the feeder into feeder segments, and conducts mathematical modeling for each equipment in the segment based on the feeder segment. The detailed line loss of each equipment makes the line loss distribution in the system clear at a glance, which is convenient for operation and maintenance personnel to scientifically manage and carry out distribution network line loss analysis and calculation, and provides a favorable basis for further optimization of the distribution network system.

Adaptive Control Strategy of Multiemergency Power Supply Network System Connected to New Energy

In order to improve the adaptive control effect of the multiemergency power supply networking system connected to new energy (NE), this paper studies the adaptive control strategy (ACS) of the multiemergency power supply networking system connected to NE by combining intelligent algorithms and determines the appropriate installation node of the distributed power supply according to the voltage stability index. Moreover, this paper proposes a method to optimize the distribution network feeder reorganization and distributed power configuration problems based on the fireworks algorithm to reduce the network loss and improve the voltage distribution. In addition, distribution network reorganization and distributed power configuration optimization can more effectively minimize network losses and improve voltage distribution. Through the experimental research, it can be seen that the ACS of the multiemergency power supply network system connected to NE proposed in this paper has the established effect.

OPTIMIZATION OF DISTRIBUTION NETWORK SECTION OPTIONS WITH THE EVALUATION OF THEIR EFFICIENCY

The article presents criteria for optimizing the sectioning of looped sections of distribution network feeders, taking into account a wide range of loads of transformer substations (TS). The main expressions for the bicriteria optimization of distribution network sectioning options are given, taking into account the minimum load losses and the average annual probabilistic undersupply of electricity (damage).

Demand side management strategy for alleviating power shortages in Nigerian power system: A case study

This paper presents the simulation of demand side management (DSM) strategy for alleviating power shortages in Nigerian power system. The frequent power outages in the Nigerian power system especially in the distribution network which is caused by schedule and unscheduled outages in the system in which the schedule outages are predominant, is as a result of inadequate electricity generation and equipment limitations to meet the current ever-growing energy demand. The distribution network feeders’ peak load and electricity supply was evaluated and data were collected from November 2017 to October 2018; to carry out the analysis of the network feeders’ load and its management. Consequently, modeling of the proposed DSM strategy in Simulink environment and its optimization was done using the binary particle swarm optimization (BPSO) algorithm and, the simulations were carried out to test the efficacy of the model. The results of the simulations of the DSM strategy showed that the proposed method has the capacity to bring the load curve closer to an objective or desired load curve thereby reducing the blackout areas of the network per outage scheduling from 63.38% or 36.62% in the existing network to 14.08% in the proposed network and also, improved the 11 kV feeders’ availability from twelve hours currently per day to twenty-four hours in the proposed network.

High-Quality Load Pattern Reconstruction from Smart Meter Data to Enhance the Assessment of Peak Power and Network Losses

The solutions recommended by international roadmaps and technical reports on smart metering refer to interval metering with time resolutions higher than 15 min to 1 h as traditionally used. Based on the characteristics of the users’ power patterns in distribution networks, this article shows that in practical cases the resolutions of the traditional metering are not sufficient to assess peak power and network losses effectively. Effective interval metering solutions should have resolutions of one minute or less. Moreover, this article shows the advantages of assessing the average power peak (amplitude and duration) and estimating the network losses through innovative solutions beyond interval metering, based on event-driven energy metering. The use of EDM significantly enhances the quality of pattern representation and reduces the amount of data required with respect to high-resolution interval metering. Based on the Pareto analysis of conflicting objectives, a novel procedure to set up the EDM thresholds is presented. The applications shown use real data and refer to a single user, some users connected to a distribution network feeder, and many users connected to a large distribution system. The EDM benefits are quantified using specific indicators that consider energy losses and peak power.

Identification method of the feeder-transformer relationship in active distribution network based on power restoration information matrix

In order to solve the problem of identification and verification of topological relationship between feeder and distribution transformer in distribution network, a new identification method of feeder-transformer relationship in active distribution network based on power restoration information matrix is proposed. Firstly, the identification model of feeder-transformer relationship is established through the distribution network feeder-transformer information matrix. Then, through the identification model of feeder-transformer relationship, the real-time power restoration information matrix (RRIM) and standard power restoration information matrix (SRIM) are established to describe the power restoration distribution transformer under real-time and standard conditions. Finally, the feeder-transformer relationship error information matrix is established through the difference between RRIM and SRIM to describe the name information of distribution transformer with misconnection and leakage on a feeder. The case analysis shows that this method can identify the feeder-transformer relationship of distribution network based on the topology information of DMS and real-time distribution transformer power restoration information. The method is simple and reliable, can better meet the actual needs of the site, and has good popularization value.

Reliability Enhancement by Strategic Placement of Remotely-Controlled Automation Devices: A Case Study on Tabriz Distribution Network

Achieving high distribution-reliability levels and concurrently minimizing operating costs are as the main issues in distribution system optimization. Determination of the optimal number and location of remote control switches (RCS) in the distribution system network is an essential issue from the reliability and economic points of view. To address these issues, this paper develops a novel multiobjective model from the distribution system viewpoint, wherein the primary objective, optimal RCS placement is implemented aiming at minimizing the operating costs, while in the second objective, the reliability index improvement is taken into account. So, a novel approach from a robust heuristic algorithm, modified non dominated sorting genetic algorithm (MNSGA-II), is developed and presented to solve this multiobjective mixed-integer non-linear programming problem. Simulation results received by the genetic algorithm have been compared with the other popular optimization algorithms, seperately. Results show that the proposed algorithm provides extensively the best performance, in terms of quality of the answer received and computational efficiency. The feasibility of the proposed algorithm was examined by application to two distribution feeders of the Tabriz city distribution network containing the fourth feeder of the TractorSazai substation.

Multi-Objective Optimization of Distributed Generation Despite Energy Storage Systems for Optimal Management

The influence of distributed generation resources and energy storage units in distribution networks is increasing. Therefore, it is essential to examine their effect on network reliability. In this study, in order to present the optimal energy management strategy in the smart distribution network, the problem of multi-objective optimization of rearrangement of distribution feeders with the presence of distributed generation sources and energy storage units has been solved in a dynamic framework. Objective functions in this study include minimization of energy losses, redistributed energy and operating costs. In order to simultaneously optimize the reliability index and other objective functions, another optimal design for the production of distributed generation units, charging and discharging of energy storage systems as well as the topology of distribution network feeders is presented. In order to solve the multi-objective optimization problem in this study, a combination of particle social algorithms and frog mutation has been used. In order to show the ability of the method in providing an optimal energy management plan in a 95-bus network has been tested.