Distribution System Feeder Research Articles

IUPQC for mitigation of electrical power quality in two feeder distribution system

This paper proposes a modified connection for a UPQC to improve the power quality of two feeders in a distribution system is the Interline Unified Power Quality Conditioner (IUPQC). IUPQC specifically aims at the integration of series VSC and Shunt VSC to provide high quality power supply by means current & voltage harmonic elimination and voltage sag/swell compensation in a of two feeders in a distribution system, so that improved power quality can be made available at the point of common coupling. The structure, control and capability of the IUPQC are discussed in this paper. The efficiency of the proposed configuration has been verified through simulation using MATLAB/ SIMULINK.

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.

A novel fuzzy-logic controller-MDsUPQC topology for power quality improvement in multi-feeder distribution system

In the current situation, the significant usage of massive non-linear functioned power electronic loads has been increased in domestic and industrial applications. The main problem of power-quality (PQ) deterioration in both voltage quality and current quality from nominal values and also damaging the single/multi feeder distribution systems. The major contribution is to alleviate the PQ issues by employing novel multi-devices unified power-quality conditioner (MDsUPQC) topology in a multi-feeder distribution system. This MDsUPQC comprises multiple voltage source inverter (VSI) devices connected with a common direct current-link (DC-link) capacitor which is controlled by a proportional-integral (PI) controller. However, this controller has some technical issues that are not suited for the regulation of common DC voltage at the desired level because of improper selection of gain values. The contribution of this work is proposing an intelligent fuzzy-logic (FL) DC-link controller-driven MDsUPQC device which evidences the intelligent knowledge base for better regulation of PQ issues. The technique and performance of the suggested strategy for PQ improvement, load sharing between feeders, and simulation results are presented with comparative analysis utilizing the MATLAB/Simulink software tool.

Rehabilitation and Techno design of Distribution transformer and 11kV feeder of a radial distribution system

In any transmission and distribution system- the performance of that system mainly depends on voltage regulation and efficiency. Hence for the better operation of the system, it is required to maintain constant voltage regulation with good power factor and low power loss throughout the feeder. This can be achieved by using various methods. Out of those, placement of a capacitor bank at the densely loaded areas is the best-proven method compared to any other method. This research work considered the feeder-5 of the Al-Uwainath primary substation which was suffering from low voltage–poor regulation- problems. Here in this research modeled and analyzed 3 different techniques for rehabilitation to this low voltage, poor regulation, and power factor problem and recommended the most efficient method out of the three methods. As a part of this project simulated the same conditions of the site after collecting the data of the feeder from the site by using ETAP software and checked the performance by calculating its voltage regulation, power losses, and power factor in all three 3 different methods and recommended the most efficient method of feeder-5 rehabilitation by comparing the results of three methods with the exciting system.

Power Quality Analysis for Light-Duty Electric Vehicles: A Case Study in Malta

This paper presents a power quality analysis for multiple electric vehicle charging stations of the AC-Level 2 type in a real-life case study. The data was collected with a power quality analyzer that measured the main distribution system feeding nine 7 kW charging stations in a commercial site with light-duty vehicles in Malta, Europe. The relevance of this study to the specific case of Malta is accentuated by the topological challenges of the country; high density of road vehicles, with 18,000 vehicles for each square kilometer; and ambitious targets of reaching carbon neutrality by 2050. Data were collected over six days on an actual charging system with real-life charging patterns. Various results are presented in this paper, including three-phase system voltages and currents, individual harmonic voltage and current components, total harmonic distortion and total current demand distortion. These measurements were compared with standardized thresholds for low-voltage equipment used in public spaces, mainly as stated in IEEE 519-2014.

Electric Water Heater Modeling for Large-Scale Distribution Power Systems Studies with Energy Storage CTA-2045 Based VPP and CVR

As the smart grid involves more new technologies such as electric vehicles (EVs) and distributed energy resources (DERs), more attention is needed in research to general energy storage (GES) based energy management systems (EMS) that account for all possible load shifting and control strategies, specifically with major appliances that are projected to continue electrification such as the electric water heater (EWH). In this work, a methodology for a modified single-node model of a resistive EWH is proposed with improved internal tank temperature for user comfort modeling and capabilities for conservation voltage reduction (CVR) simulations as well as Energy Star and Consumer Technology Association communications protocol (CTA-2045) compliant controls, including energy storage calculations for “energy take”. Daily and weekly simulations are performed on a representative IEEE test feeder distribution system with experimental load and hot water draw (HWD) profiles to consider user comfort. Sequential controls are developed to reduce power spikes from controls and lead to peak shavings. It is found that EWHs are suitable for virtual power plant (VPP) operation with sustainable tank temperatures, i.e., average water temperature is maintained at set-point or above at the end of the control period while shifting up to 78% of EWH energy out of shed windows per day and 75% over a week, which amounts to up to 23% of the total load shifted on the example power system. While CVR simulations reduced the peak power of individual EWHs, the aggregation effect at the distribution level negates this reduction in power for the community. The EWH is shown as an energy constant load without consistent benefit from CVR across the example community with low energy reductions of less than 0.1% and, in some cases, increased daily energy by 0.18%.

Rapid Power Restoration and Network Reconfiguration for Power Distribution System Reliability Enhancement: A Case Study on Bahir Dar Power Distribution Systems

Reliability improvement of power distribution systems is pre-request for economic and social development of any country. Currently, there is rapid growth of industrial, commercial, residential and other service providing institutions. All of these institutions need reliable power supply. Due to this, utilities must work hard and ensure that the customers are getting the reliable power supply. However, higher power interruption frequency and longer interruption duration is the most serious problem facing Ethiopian power distribution systems and this problem affects day to day activity of customers. In this paper, rapid power restoration and network reconfiguration using optimal placement of switching/automating devices is performed. Network reconfiguration and rapid power restoration is performed to improve the reliability problem of Bahir Dar power distribution system. Optimal placement of switching/automating devices for network reconfiguration is determined by Genetic Algorithm (GA) optimization technique using MAT LAB software and rapid power restoration is carried out by Prim’s Algorithm (PA) used for constructing Minimum Spanning Tree (MST) in MAT LAB software. The study is tested at Bata 34-bus feeder of Bahir Dar distribution system. The existing network is assessed and the reliability indices such as SAIFI, SAIDI, ASAI, CAIDI and EENS are evaluated using ETAP 12.6.0 software.

Revenue Metering of Unbalanced Prosumers in Energy Communities

The presence of power generating plants owned by prosumers may lead to unbalanced bidirectional energy flows at the points of connection to the relevant distribution systems. This will impact future energy communities, where appropriate metering within the community is a crucial issue for billing purposes. This paper shows that the current metrics for active energy measurement and the registration of three-phase revenue meters may fail to fairly charge unbalanced prosumers for their use of the distribution system as an inherent phase-to-phase balancer. On the other hand, it is proven here that adopting metrics based on positive sequence power/energy measurement would lead to more fair billing within the community. A comparative study was performed using a simplified but realistic model of a distribution system feeding two prosumers (i.e., an archetype of an energy community). First, representative case studies were considered. Then, a more realistic simulation of a single day of operation was conducted. The main contribution of the paper is a detailed and systematic comparison of the methods used for measuring and sorting energy into registers in revenue meters to support the ongoing discussions about fair metering within future energy communities.

Enhancing voltage regulation using 5‐level TCHB based DVR in radial secondary distribution feeder system

SummaryThe voltage quality issues shows the significant effect on the performance of radial secondary distribution feeder. This paper aims to enhance the voltage regulation of radial secondary distribution feeder system using 5‐level TCHB inverter based dynamic voltage restorer. Series voltage drop is the major factor causes poor voltage regulation. A 5‐level TCHB inverter based DVR is used to inject the same amount of voltage dropped by series impedance. The DVR injects voltage with proper magnitude, phase and frequency with the proposed single phase PLL based SRF control circuitry. This enhances the voltage regulation by maintaining the load voltage at its rated value. Both the simulation and hardware results shows the enhancement of voltage regulation with mitigation using DVR.

Comparative Performance of DVR and STATCOM for Voltage Regulation in Radial Microgrid with High Penetration of RES

In recent years, the penetration of renewable energy sources (RES) in microgrids and distribution system feeders has increased manifold. Moreover, the advancement of power electronics-based devices in the distribution system has significantly increased the number of sensitive loads. Variations in the voltage under intermittent RES create functional problems with sensitive loads, necessitating voltage regulators (VR) installation. In this paper, two custom power devices: dynamic voltage restorer (DVR) and static synchronous compensator (STATCOM), used for voltage regulation in a microgrid, are investigated under different operating conditions. The efficacy of DVR and STATCOM for voltage regulation in an 11-node radial microgrid with high penetration of RES is simulated under a MATLAB Simulink environment. Furthermore, the simulated microgrid voltage profile results are analyzed to evaluate the efficacy of both voltage regulators.

Improved Heap-Based Optimizer for DG Allocation in Reconfigured Radial Feeder Distribution Systems

This article presents an improved heap-based optimizer (IHBO) for dealing with the optimal combination of power distribution system reconfiguration and distributed generators allocation in power distribution systems (PDSs). The suggested IHBO tries to improve on the conventional HBO by integrating an efficient exploitation mechanism to increase the exploring around the leadership position, with the goal of increasing its global search skills and avoiding being trapped in a local optimum. Three PDSs are studied, including a conventional IEEE PDS of 33-bus and two actual PDSs of 59-bus Cairo distribution system, Egypt, and 84-bus Taiwan Power Company (TPC), Taiwan. For the IEEE standard system, the proposed IHBO algorithm achieves the maximum reduction of power losses of 69.44%, 72.29%, and 74.725% for low, nominal, and high loadings, respectively. For the Cairo PDS, the proposed IHBO obtains the best performance with the least minimum, average and maximum fitness of 1.4149, 1.444, and 1.496, respectively. For the Taiwan PDS, it achieves the least minimum, average and maximum losses of 240.88, 264.16, and 308.49 kW, respectively. It also exhibited a significant improvement in voltages throughout the PDS buses.

Time series-based detection and impact analysis of firmware attacks in microgrids

Distributed generation (DG) and microgrids (MG) are critical components of future power systems. However, the reliance of DGs and MG on resource-constrained embedded controllers for their operation renders them potential cyberattack targets. In this paper, we analyze the adversarial objectives of attackers attempting switching and control input modification attacks by manipulating controller firmware. We demonstrate the attack impact in the simulated Canadian urban distribution feeder system consisting of four DGs. To detect malicious firmware within the inverter controllers, we propose utilizing custom-built Hardware Performance Counters (HPCs) in conjunction with Time Series Classifiers (TSCs). TSCs respect the sequential order and attributes of the utilized custom-built HPCs sampling the controller’s firmware. Our experimental results demonstrate that malicious firmware can be successfully identified with 97.22% accuracy using a TSC trained on a single custom-built HPC.

Economic dispatch of an islanded microgrid

Microgrids are increasingly becoming popular to improve energy access and increase the resiliency of weakly connected rural networks. The economic operation of these microgrids with renewable energy resources is key for maximizing the benefits. The objective of this paper is to implement the economic dispatch of a microgrid using quadratic programming, considering the active and reactive power capability of the renewable energy resources. The open distribution system simulator (OpenDSS) is used for obtaining the load flow of the distribution network, and the converged solution is given as input to MATLAB for optimization. The simulation is carried out for one day with a variation of hourly load, solar PV radiation, and wind in both grid-connected and islanded modes under six different cases. The methodology is implemented on a modified IEEE-13 node test feeder distribution system. The simulation result shows that the microgrid with distributed generation (DG) capable of supplying both active and reactive power under islanded conditions is economical when compared to the grid-connected mode. The novelty of the work is that it considers the capability of distributed generation to supply both active and reactive power. That can make it fully autonomous as it can meet the hourly load requirement of the network under islanding mode as per IEEE Standard 1547.4.

Voltage Regulation in a Radial Microgrid with High RES Penetration

Increasing installation of Renewable Energy Sources (RESs) in microgrids and distribution system feeders benefits the power system in many ways, such as increasing power availability and reliability, but they also cause various power quality issues, such as overvoltage and undervoltage, due to their intermittent nature. The sensitive loads, such as Constant Power Load (CPL), are affected by these voltage fluctuations. The approach proposed in this paper is to install a Dynamic Voltage Regulators (DVR) adjacent to the RES to suppress the voltage issue caused by it while leaving the sensitive load operation unharmed. The proposed concept is duly endorsed with analysis and simulations in MATLAB/Simulink environment.

Reliability Assessment of Power Distribution System Using Relative Customer Average Interruptions Duration Index Model

Reliability assessment of power distribution system deals with the adequacy of overall system supply and indicates the system behaviour and response at the customer end. In order to attain satisfactory degree of reliability in electric power distribution system, there is the need to develop a model that will improve the three major system reliability indices via Systems Average Interruptions Duration Index (SAIDI), Systems Average Interruptions Frequency Index (SAIFI) and Customer Average Interruptions Duration Index (CAIDI). This research paper therefore, developed a Relative CAIDI model for assessment of reliability indices of electrical power distribution system. In this paper, ten (10) years outage data from selected distribution feeders of Ibadan, Ikeja and Port-Harcourt distribution systems were obtained and analyzed using curve fitting tools in MATLAB. The system reliability indices served as input parameters for the development of Relative CAIDI model. The best curves that fitted the relationship between the Relative CAIDI and the number of feeders were obtained using Lagrange polynomial functions, Newton polynomial functions and Chebyshev polynomial functions as performance evaluation metrics. The results showed that Ibadan, Ikeja and Port-Harcourt distribution systems had Relative CAIDI of 0.718, 0.3976 and 0.5279 respectively and the validation results produced by Largrange polynomial function, Newton polynomial function and Chebyshev polynomial function were 0.717, 0.3979 and 0.5278 respectively. The model developed is a polynomial of order six which depends majorly on the power requirements of the distribution systems. The developed model can be used for effective reliability assessment of electrical power distribution systems as well as forming a base-line information for system planning and maintenance strategies. Keywords: Reliability Indices, SAIDI, SAIFI, CAIDI, Chebyshev Polynomial Function, Lagrange Polynomial Function, Newton Polynomial Function. DOI: 10.7176/NCS/14-01 Publication date: August 31 st 2022

An Optimal Algorithmic Approach to Efficiently Automate Fault Isolation and Service Restoration on an Arbitrary Distribution Feeder System

Weather-related or other types of faults can negatively impact the continuity of the electricity delivery to the consumers and, thus, lead to poorer reliability scores. 90% of customer outage-minutes are due to events which affect local distribution systems. The radial configuration is simple and has a low cost design; however, when a fault occurs it often causes power outages beyond the location of the fault itself. Therefore, it is beneficial for utilities to automatically isolate the fault and, thus, restore power to as many consumers as possible. The benefits of fault isolation and service restoration include, but are not limited to: enhanced reliability and resiliency, reduced loss of revenue to the utility, and enhanced comfort and satisfaction for the utility’s consumers. This paper provides an algorithm to quickly isolate a fault and automatically restore power to as many nodes of the distribution system as possible by opening and closing switches already placed within the system. The expert model and centralized algorithm that are proposed in this paper guarantee an optimal solution and a short run-time regardless of the size of the distribution system. A mathematical proof of the optimal nature of the solution is provided. In addition, the model is validated in practice, solving two different-sized systems.

Fault prediction model on electrical power network using artificial neural network-based time series: A case study of Ayede-Eruwa/ Lanlate Feeder

Increase in size of electrical power network usually results in a rise in fault level and consequently in huge economic losses to energy providers and consumers in the distribution systems. Therefore, it is very important to be proactive in dealing with faults on distribution feeder systems not only to reduce financial havoc, but to save lives and improve the quality of life of the people. A case study of Ayede-Eruwa/Lanlate Oyo State, Nigeria 33kV line is considered. An Artificial Neural Network based Time Series (ANN-TS) fault predictive model is developed for forecasting of faults on the above chosen electrical power network. Daily forced outage readings of the substation’s feeders for three years were collected and modeled using a three-layer feed-forward network ANN-TS. The results in the frequency of fault prediction show that there is an overlap between the observed and predicted values. The annual Mean Average Percentage Error (MAPE) varies between 0.004% and 25%, and the feeders’ average MAPE ranges from 6% to 10%. The fault duration annual MAPE varies between 0.001% and 25.54% while the feeders’ average MAPE varies between 6% and 11%. The energy loss prediction follows the same trend with the annual MAPE alternating between 0.01% and 26.75%, andthe feeders’ average MAPE between 6% and 10%. The average overall MAPE of each feeder is between 6% and 10% which indicates that the developed model is about 90% to 94% accurate. Although, the model is designed for Ayede-Eruwa/Lanlate feeder, it could be utilized for effective prediction of faults in any power distribution network.

Decoupled probabilistic feeder hosting capacity calculations using general polynomial chaos

This paper introduces a decoupled method of calculating the PV hosting capacity of low voltage distribution system (LVDS) feeders for new solar photovoltaics (PV) installations. The hosting capacity calculation of LVDS is a multidimensional stochastic problem. A general polynomial chaos-based probabilistic power flow is used to solve this problem, as it allows for fast computation times without any compromise in accuracy. Two types of uncertainties exist in the hosting capacity calculation problem: planning level uncertainties such as size, location, type, and number of PV installations and operational uncertainties such as consumer load and PV generation. These two types of uncertainties are usually sampled together in probabilistic hosting capacity approaches. In this paper, a decoupled approach is presented where the impact of planning level scenarios on the probability of violation of operational limits is studied. The highest total PV among the planning scenarios inside the probabilistic bound of the operational limit is termed as the hosting capacity of the feeder. The results show that hosting capacity depends upon the planning uncertainties and operational variables, and decoupling them gives a more concise picture of the impact of different uncertainties.

Forming Interphase Microgrids in Distribution Systems Using Cooperative Inverters

Interphase-microgrids formed by three islanded single-phase feeders in distribution systems are proposed in this paper. Loss of utility caused by natural and human-made disasters may isolate each residential subdivision from the utility. In this case, the household loads are supplied by distributed generation (DG) units which may not be enough to meet the load demand. This can lead to deviations in voltage and frequency, and the deviations may vary for each phase. The proposed solution is to form an interphase-microgrid by seamlessly interconnecting the islanded single-phase feeders. This interphase-microgrid can effectively balance the load demands and DG generation in distribution systems after losing the utility supply. This paper presents different case studies to demonstrate the viability of forming interphase-microgrids for residential distribution systems.

Fault location and detection techniques in power distribution systems with distributed generation: Kenitra City (Morocco) as a case study

Rapid detection and efficient diagnosis of power outages can improve reliability, stability, and energy quality. Fault diagnosis is based on fault detection, location, isolation, and quick power restoration. An efficient solution for fault diagnosis could be artificial intelligent-based multi-agent systems. This paper proposed a new approach based on the multi-agent system for fault location and autonomous power restoration in the power distribution system that contains distributed generation (DG). Effective fault detection, localization, and high protection are required to control systems from the blackout and configure them appropriately after an outage. This paper tests the proposed protection approach using an open ring feeder distribution system of Kenitra city, Morocco. In addition, the impact of DG integration on fault location and multiple faults is addressed in this paper, with suitable backup protection given via agent coordination.