Rural Distribution Feeder Research Articles

Cost Effective Reliability Improvements in 33kV/11kV Electricity Distribution Networks – A Case Study in Western Province South 1, CEB, Sri Lanka

Electricity Distribution system in Sri Lanka consists of 33 kV, 11 kV and LV (400V/230 V) networks. Providing reliable supply to the end user is a challenging task to any utility. Therefore, utility is committed to develop its network to provide reliable supply to electricity users by investing in system developments. In this research, a methodology is introduced for selecting cost-effective solutions to improve the reliability of the 33 kV and 11 kV distribution systems among different proposals. Improvement of conductor, its insulation and protection of short duration faults are focused to develop the system in this research. Part of the method developed includes a software tool (named as DisFeeRIA) to analyse the reliability indices and economic parameters for the relevant proposal. Database of the DisFeeRIA software tool includes failure rate improvement, mean time to repair and costing of each option under consideration. Medium Voltage Underground Cable (MVUGC), Medium Voltage Aerial Bundle Conductor (MVABC), Medium Voltage Covered Conductor (MVCC), Room Temperature Vulcanizing (RTV) Si-R coating on existing bare overhead line ceramic insulators are considered as options for improving conductor and its insulation. One of the latest and innovative technologies used in distribution network, Pulse Closing Technology, is used to reduce short duration faults (momentary interruptions) and enhance the lifetime of the equipment used in distribution networks. Developed tool and method were tested by a case study done for distribution network in Western Province South – 01 of Ceylon Electricity Board (CEB). Three (03) feeders were selected in different areas from Urban, Coastal and Rural for this purpose. MVCC and RTV Si-R coating for existing Medium Voltage Bare Overhead lines can be used for improving the reliability of Coastal, Urban and Rural distribution feeders in a cost-effective manner after proper analysis, based on technical and economic aspects. However, depending on the safety concerns, MVUGC or MVABC can be used irrespective of the economical aspect. Intelirrupter pulse closers can be used to replace traditional auto recloses, especially with MVUGC, MVABC and MVCC in rural feeders. It helps to reduce momentary interruption failures and enhance the equipment lifetime by reducing thermal and mechanical stress on all distribution equipment and cables. Furthermore, it improves the power quality of the system.

Fault Location Estimator Design for Power Distribution System Using Artificial Neural Network

Fault location in distribution system is critical issue to increase the availability of power supply by reducing the time of interruption for maintenance in electric utility companies. Fault location estimator for power distribution system using artificial neural network is developed for line to ground, line to line, line to line to ground and three phases to ground faults in distribution system. To develop this estimator is one of rural radial power distribution feeder in Ethiopia, south west reign, Aba substation Tarcha line feeder is used as a test feeder. This feeder is simulated using ETAP software to generate data for different fault condition, with different fault resistance and loading conditions, which is the fault phase voltage and current. The generated data is preprocessed and put as an input for neural network to be trained. MATLAB R2016a neural network toolbox to train ANN and programming toolbox is used to develop graphic user interface for fault estimator. The feed forward multi-layer network topologies of neural network with improved back propagation, Liebenberg Marquardt learning algorithm is used to train the network. After the network is trained the mean square error performance, regression plot and error histogram analysis was made and found to have an excellent performance with regression coefficient 0.99929 , validation performance of 0.000102 and error histogram range 0.015 to 0.019. In this thesis for practical implementation the fault records at the test feeder is handled by intelligent electronic device (IED) installed at the substation feeders. The fault record of IED can be read by PCM600 tool using laptop or manually using IEDs human machine interface, this fault recorded data feed to the graphic user interface to estimate the fault location as well as the fault type. Finally it is found that artificial neural networks are one of the alternate options in fault estimator design for distribution system where sufficient distribution network data are available with narrow fault location distance range from the substation. This has benefits in assisting for maintenance plan, saving efforts in fault location finding and economic benefits by reducing interruption time. Keywords : Power distribution, artificial intelligence, neural network, feed forward network DOI: 10.7176/JETP/12-5-01 Publication date: November 30 th 2022

A Critical Analysis of Modeling Aspects of D-STATCOMs for Optimal Reactive Power Compensation in Power Distribution Networks

Distribution static compensators (D-STATCOMs) can enhance the technical performance of the power distribution network by providing rapid and continuous reactive power support to the connected bus. Accurate modeling and efficient utilization of D-STATCOMs can maximize their utility. In this regard, this article offers a novel current-injection-based D-STATCOM model under the power control mode of operation for the reactive power compensation of the power distribution network. The versatility of the proposed D-STATCOM model is demonstrated by combining it with two of the most established distribution load flow techniques, viz., the forward–backward sweep load flow and the BIBC–BCBV-matrix-based direct load flow. Further, the allocation of the proposed D-STATCOM model is carried out under a multiobjective mathematical formulation consisting of various technical and economic indices such as the active power loss reduction index, voltage variation minimization index, voltage stability improvement index and annual expenditure index. A novel parameter-free metaheuristic algorithm, namely a student-psychology-based optimization algorithm, is proposed to determine the optimal assignment of the different number of D-STATCOM units under the multiobjective framework. The proposed allocation scheme is implemented on a standard 33-bus test system and on a practical 51-bus rural distribution feeder. The obtained results demonstrate that the proposed D-STATCOM model can be efficiently integrated into the distribution load flow algorithms. The student-psychology-based optimization algorithm is found to be robust and efficient in solving the optimal allocation of D-STATCOMs as it yields minimum power loss compared to other established approaches for 33-bus PDNs. Further, the economic analysis carried out in this work can guide network operators in deciding on the number of D-STATCOMs to be augmented depending on the investment costs and the resulting savings.

Impact Assessment and Mitigation Techniques for High Penetration Levels of Renewable Energy Sources in Distribution Networks: Voltage-control Perspective

The integration of renewable distributed generation (RDG) into distribution networks is promising and increasing nowadays. However, high penetration levels of distributed generation (DG) are often limited as they may have an adverse effect on the operation of distribution networks. One of the operation challenges is the interaction between DG and voltage-control equipment, e. g., an under-load tap changer (ULTC), which is basically designed to compensate for voltage changes caused by slow load variations. The integration of variable DGs leads to rapid voltage fluctuations, which can negatively affect the tap operation of ULTC. This paper investigates the impact of high penetration levels of RDG on the tap operation of ULTC in distribution networks through simulations. Various mitigation techniques that can alleviate this impact are also examined. Among these techniques, constant power-factor mode is regarded as the best trade-off between the simplicity and effectiveness of minimizing the number of tap operations. Simulations are performed on a Canadian benchmark rural distribution feeder using OpenDSS software.

Improving the lightning performance of distribution lines using high CFO structures

The paper investigates the improvement of the lightning performance of distribution lines due to the increase in the line critical flashover voltage (CFO) from 95 kV to 170 kV. Initially, a research project on lightning protection carried out in the 1980′s and the proposed modifications on the distribution line structures in order to increase their CFO are described. A methodology for the lightning flashover rate assessment, including the variation of the soil resistivity in a probabilistic model, is presented. Additionally, field data on the lightning performance of two rural distribution feeders, one with 95 kV CFO and the other with 170 kV CFO, are analyzed. Altogether, the feeders are approximately 1200 km long and are located in the same region. Their lightning performance refers to four years of operation and 3800 sustained power outages. The field data are compared with the theoretical assessment carried out using the proposed methodology as well as with the methodology used in the 1980′s, and the results are analyzed.

Full versus decoupled constant matrices to speed up power system state estimation

This paper presents a performance evaluation of two solutions to reduce computational burden of the traditional Weighted Least Squares Algorithm for power system state estimation: Simplified methods SWLS1 / SWLS2 based on full constant matrices and Fast decoupled FDWLS based on decoupled constant matrices. First, the algorithms were tested on IEEE 14 and 118 bus transmission systems. Second, the solutions were tested on a rural distribution feeder to evaluate the response of the algorithms to high R/X ratio. Results show that for transmission systems, FDWLS is the fastest method but more sensitive to erroneous measurements. Simplifications considered in FDWLS, are not valid in distribution systems with high R/X ratio this results in slowing down the algorithm convergence speed considerably compared to SWLS2 which performs well. SWLS2 algorithm presents a promising solution to reduce computation time for application in future smart grid.

A cascade perceptron and Kohonen network approach to fault location in rural distribution feeders

The location of faults in the distribution system is one of the most important problems for utilities in the sector now since they directly impact the quality of the energy supply, as well as economical. Thus, the faster the fault identification and the electrical energy prompt reestablishment, the better are the quality indicators of these companies. In this scenario, this work presents an alternative and efficient method that uses artificial neural networks to locate faults in distribution feeders. The developed methodology was applied using real data from a rural distribution system. Thus, through simulations in the ATPDraw software, it is possible to obtain current and voltage values of the studied feeder, these being the inputs of the developed neural networks. The neural networks were developed in the Matlab® software in two stages: first, a Perceptron Multiple Layers networks perform the classification of the types of faults. These, in sequence, are used to select the Kohonen Self-Organizing Maps employed in the second stage to the location of the feeder fuse switch that acted at the time of the fault. Simulation results from the real system are presented to validate the proposed methodology, making it possible to accurately estimate the equipment that operated when the interruption occurred, which provides greater speed in reestablishing the electricity supply in the affected region, increasing the quality indicators and reducing maintenance and regulatory costs of electrical utilities.

Impacts of Placement of Wind Turbine Generators on IEEE 13 Node Radial Test Feeder In-Line Transformer Fuse-Fuse Protection Coordination

The ever increasing global demand on the electrical energy has lead to the integration of Distributed Generators (DGs) onto the distribution power systems networks to supplement on the deficiencies on the electrical energy generation capacities. The high penetration levels of DGs on the electrical distribution networks experienced over the past decade calls for the grid operators to periodically and critically asses the impacts brought by the DGs on the distribution network operations. The assessment on the impacts brought by the DGs on the distribution network operations is done by simulating the dynamic response of the network to major disturbances occurring on the network like the faults once the DGs have been connected into it. Connection of Wind Turbine Generators (WTGs) into a conventional electrical energy distribution network has great impacts on the short circuit current levels experienced during a fault and also on the protective devices used in protecting the distribution network equipment namely; the transformers, the overhead distribution lines, the underground cables and the line compensators and the shunt capacitors commonly used/found on the relatively long rural distribution feeders. The main factors which contribute to the impacts brought by the WTGs integration onto a conventional distribution network are: The location of interconnecting the WTG/s into the distribution feeder; The size/s of the WTG/s in terms of their electrical wattage penetrating the distribution network; And the type of the WTG interfacing technology used labeled/classified as, Type I, Type II, Type III and Type IV WTGs. Even though transformers are the simplest and the most reliable devices in an electrical power system, transformer failures can occur due to internal or external conditions that make the transformer incapable of performing its proper functions. Appropriate transformer protection should be used with the objectives of protecting the electrical power system in case of a transformer failure and also to protect the transformer itself from the power system disturbances like the faults. This paper was to investigate the effects of integrating WTGs on a distribution transformer Fuse-Fuse conventional protection coordination scheme. The radial distribution feeder studied was the IEEE 13 node radial test feeder and it was simulated using the Electrical Transient Analysis Program (ETAP) software for distribution transformer Fuse-Fuse protection coordination analysis. The IEEE 13 Node radial test feeder In-line transformer studied is a three-phase step down transformer having a star solidly grounded primary winding supplied at and a star solidly grounded secondary winding feeding power at a voltage of . The increase on the short circuit currents at the In-line transformer nodes due to the WTG integration continuously reduces the time coordination margins between the upstream fuse F633 and the downstream fuse F634 used to protect the transformer.

Impacts of Placement of Wind Turbine Generators on IEEE 13 Node Radial Test Feeder In-Line Transformer Fuse-Fuse Protection Coordination

The ever increasing global demand on the electrical energy has lead to the integration of Distributed Generators (DGs) onto the distribution power systems networks to supplement on the deficiencies on the electrical energy generation capacities. The high penetration levels of DGs on the electrical distribution networks experienced over the past decade calls for the grid operators to periodically and critically asses the impacts brought by the DGs on the distribution network operations. The assessment on the impacts brought by the DGs on the distribution network operations is done by simulating the dynamic response of the network to major disturbances occurring on the network like the faults once the DGs have been connected into it. Connection of Wind Turbine Generators (WTGs) into a conventional electrical energy distribution network has great impacts on the short circuit current levels experienced during a fault and also on the protective devices used in protecting the distribution network equipment namely; the transformers, the overhead distribution lines, the underground cables and the line compensators and the shunt capacitors commonly used/found on the relatively long rural distribution feeders. The main factors which contribute to the impacts brought by the WTGs integration onto a conventional distribution network are: The location of interconnecting the WTG/s into the distribution feeder; The size/s of the WTG/s in terms of their electrical wattage penetrating the distribution network; And the type of the WTG interfacing technology used labeled/classified as, Type I, Type II, Type III and Type IV WTGs. Even though transformers are the simplest and the most reliable devices in an electrical power system, transformer failures can occur due to internal or external conditions that make the transformer incapable of performing its proper functions. Appropriate transformer protection should be used with the objectives of protecting the electrical power system in case of a transformer failure and also to protect the transformer itself from the power system disturbances like the faults. This paper was to investigate the effects of integrating WTGs on a distribution transformer Fuse-Fuse conventional protection coordination scheme. The radial distribution feeder studied was the IEEE 13 node radial test feeder and it was simulated using the Electrical Transient Analysis Program (ETAP) software for distribution transformer Fuse-Fuse protection coordination analysis. The IEEE 13 Node radial test feeder In-line transformer studied is a three-phase step down transformer having a star solidly grounded primary winding supplied at and a star solidly grounded secondary winding feeding power at a voltage of . The increase on the short circuit currents at the In-line transformer nodes due to the WTG integration continuously reduces the time coordination margins between the upstream fuse F633 and the downstream fuse F634 used to protect the transformer.

Highlighting the Importance of Chronology on Voltage Protection and Control in Active Distribution Networks

This paper highlights the importance of chronology on voltage protection and control apparatuses in studies of voltage security in active distribution networks with high generation capacity. This paper presents simulation results of a real-life example of a long rural distribution feeder having three voltage regulators in cascade, and a customer whose demand accounts for a large percentage of the total feeder load. The customer is also an independent power producer and its location at the far end of the feeder yields an intricate voltage protection coordination when the customer ramps up and down its own generation at the peak-demand period.

Sobretensiones por Ferroresonancia en un Sistema de Distribución Eléctrica Rural: Reporte de Caso y Simulación

- El objetivo del trabajo presentado fue el de analizar un caso de sobretension en un sistema de distribucion de energia electrica rural (13,2kV) perteneciente a una Cooperativa de Electricidad del sudeste de la Policia de Buenos Aires, Rep. Argentina. A partir de los parametros que componen el circuito electrico se modelo la red dentro del entorno del programa computacional Electromagnetic Transients Program, con el fin de evaluar su comportamiento ante distintas maniobras de interrupcion y estados de carga. El analisis de la simulacion demostro que, en ciertas situaciones de operacion y carga, se conjugaron las condiciones para la ocurrencia del fenomeno de ferrorresonancia, ocasionando la elevacion de tension de alimentacion en transformadores monofasicos. Considerando los resultados del estudio, se brindaron pautas a tener en cuenta para la prevencion y control del fenomeno

Loss Reduction and Voltage Profile Improvement in a Rural Distribution Feeder Using Solar Photovoltaic Generation and Rural Distribution Feeder Optimization Using HOMER

Abstract Rural Electricity is lagging in terms of service as well as penetration of power. Most of the rural householders do not have power supply, if at all they have high in voltage fluctuations and system losses. Due to this, the performance of distribution system becomes inefficient. Optimal placement and sizing of Distribution Generator (DG) in the distribution system will improve the performance of the distribution system. This paper analysis a practical rural feeder of 3.06 MW peak load in Mysuru, Karnataka, India. A methodology used for finding optimal placement and sizing of DG in the rural feeder. The practical rural feeder is simulated in Power World Simulator (PWS) and analyze the voltage magnitude and system losses. Simulation results shows that optimal placement and sizing of DG will improve the voltage profile within the acceptable limits and reduce the system losses. Hybrid Optimization of Multiple Electric Renewables (HOMER) optimization analysis designs best system model by considering different constraints and with Renewable Energy sources (RES) for the rural distribution feeder.

Optimal Capacitor Placement in Radial Distribution Feeders Using Fuzzy-Differential Evolution for Dynamic Load Condition

This paper proposes new methods to select the optimal values of fixed and switched shunt capacitors in Radial distribution feeders for varying load conditions so as to maximize the annual savings and minimizes the energy loss by taking the capacitor cost into account. The identification of the weak buses, where the capacitors should be placed is decided by a set of rules given by the fuzzy expert system. Then the sizing of the fixed and switched capacitors is modeled using differential evolution (DE) and particle swarm optimization (PSO). A case study with an existing 15 bus rural distribution feeder is presented to illustrate the applicability of the algorithm. Simulation results show the better saving in cost over previous capacitor placement algorithm.

Reliability Indices Evaluation of a Real Time Rural Radial Distribution Feeder

Estimation of the customer oriented, load and energy orientated indices are very helpful for assess the harshness of the system failure in a radial distribution feeder for the future purpose of prediction analysis. It can be assessed by means past performance of an arrangement. In reality, at the present time, they are extensively used for future presentation. These indices are used in the distribution system operation and planning studies. Distribution system reliability evaluation is a measure of continuity and quality of power supply to the consumers, which mainly depends on interruption profile, based on system topology and component reliability data. The paper primarily presents the real time radial feeder; the reliability is calculated in two stages. One by insertion capacitor at weak voltage nodes for augmentation of voltage profiles and plummeting the total system losses. Second by placing protective apparatus (isolators) in the feeder and enhance the reliability indices. Paper attempts a successful technique for real time valuation of distribution load flow solutions with a goal of obtaining voltage profiles and total system losses. The voltage profiles improvement and reducing losses by placing capacitors at weak voltage profile nodes using Particle Swarm Optimization (PSO) technique. Reliability Indices are premeditated for the existing feeder prior to and after placement of isolator. Load diversity factor is used for analysis of load data for real time system. The paper presents a topological characteristic of a radial distribution feeder have been fully utilized to make the direct load flow solution is possible. This paper also presents an approach that determines optimal location and size of capacitors on existing radial distribution systems to improve the voltage profiles and reduce the active power loss. The performance of the method was investigated on an 11kV real time rural PantramPalli radial distribution feeder as system of case study. A matlab program was developed and results are presented.

Impact comparison of PV system integration into rural and urban feeders

This paper is directed to evaluate the impact that the future widespread use of photovoltaic grid connected systems (PVGCSs) will have on feeder operation. With a view to achieve a global vision of this impact, the present work investigates representative feeders located in different latitudes. Actual rural and urban distribution feeders belonging to the Spanish electric utility have been selected and analyzed in both northern and southern latitudes. The analysis identifies the operating variables to assess the PV impact in the different feeders. These critical variables are related to the design and performance characteristics of the feeder. Meteorological conditions at the installation site, load patterns, PV allocation and penetration are the main factors affecting this PV impact.

A fault location technique for rural distribution feeders

This work presents a digital fault location technique for rural distribution feeders, using the voltage and current data at a single location. Rural distribution feeders include single-phase, two-phase, and three-phase laterals off a main three-phase primary distribution feeder. The fault location scheme presented here attempts to account for the multiphase laterals, the unbalanced conditions, and the unsymmetrical nature of distribution feeders by continually updating voltage and current vectors at set locations within the system. The updated voltage and current vectors are the estimates of the 60-Hz phasor quantities obtained using a recursive optimal estimation algorithm. The distance to the fault is then estimated using a method based on the apparent impedance approach and the updated voltage and current vectors. Another consideration is the ability to determine the fault location on a lateral. A simulation of an actual rural distribution feeder using the Electromagnetic Transients Program (EMTP) is used to test the approach.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Modeling and analysis of rural electric distribution feeders

The quality of service provided to rural electric customers can be improved with the accurate modeling and analysis of a distribution feeder. With the use of an analysis program developed for a personal computer, it is possible for an engineer to solve existing feeder voltage profile and loss problems and to plan feeder additions that will improve the quality of service to the customers with reduced losses to the cooperative. The authors describe the accurate model of a distribution feeder and its devices that are incorporated into a radial distribution analysis program (RDAP) developed for the personal computer. An example rural distribution feeder is modeled to demonstrate how the program is used to solve typical design and operational problems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Routing Optimization of Primary Rural Distribution Feeders

Routing Optimization of Primary Rural Distribution Feeders

Routing Optimization of Primary Rural Distribution Feeders

This paper deals with the problem of selecting the optimal route for a primary distribution feeder radiating from a rural substation at a given location and feeding a number of loads with known demands and locations. This is posed as an optimization problem of minimizing an objective cost function subject to voltage regulation, current carrying capacity, and meeting the load constraints. The case of a straight feeder with perpendicular branchings is first considered. Piecewise linear feeders are treated using linear programming and nonlinear optimization techniques. Comparison between the results achieved through the different models when applied to a typical feeder is included.