16 results
Search Results
2. Lifetime Estimation and Optimal Maintenance Scheduling of Urban Oil-Immersed Distribution-Transformers Considering Weather-Dependent Intelligent Load Model and Unbalanced Loading.
- Author
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Gorginpour, Hamed, Ghimatgar, Hojat, and Toulabi, Mohammad Sedigh
- Subjects
REMAINING useful life ,DEGREE of polymerization ,ELECTRIC power distribution ,LOAD forecasting (Electric power systems) ,OIL filters ,MACHINE learning - Abstract
Electricity distribution companies are in-charge-of supplying stable electric energy to urban customers over a wide geographical area. In these distribution networks, large number of Distribution-Transformers (DTs) are installed on towers or in electric-rooms with the ratings below 1000 kVA, which are the most important assets of distribution companies. Periodic maintenance and test services are not economically feasible for all in-operation transformers. Hence, estimating the remaining useful life and scheduling the maintenance times of DTs are of great technical and economic importance. An analytical approach is presented in this paper for predicting lifetime of DTs based on degree of polymerization. An appropriate Machine-Learning (ML) algorithm trained by measured data is selected for forecasting driven load according to the ambient temperature and humidity and day-hour schedules. The relation of Hot-Spot-Temperature in IEC60076∼7 is modified based on the measured data for accounting unbalanced-loading. Neutral-current is predicted using a trained ML-model. Another approach is proposed for determining times of oil filtering services aiming to minimize the maintenance cost and maximizing the remaining life. The proposed lifetime estimation method is validated by comparing its results with the damaged DT data of a sample network chosen as the case studies for this research, i.e., Bushehr province, Iran. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. A Stochastic Markov Model for Maintenance Scheduling in the Presence of Online Monitoring System.
- Author
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Ardabili, Habib Allah Ravaghi, Haghifam, Mahmoud-Reza, and Abedi, Seyyed Mostafa
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ONLINE monitoring systems ,MARKOV processes ,STOCHASTIC models ,ELECTRIC power distribution ,SPARE parts ,MAINTENANCE ,RELIABILITY in engineering - Abstract
Active electricity distribution systems (AEDS) play an important role on the social welfare that is highly relies on the reliability of these systems. In this regard, maintenance management tries to decrease component failures via repairing component that are more possible to be failed in operation time. In this manuscript, a stochastic MINLP maintenance scheduling model is proposed in which the reliability of AEDS's equipment is considered through employing a three-state Markov model. This model helps us to embed the uncertainty of AEDS's equipment service restoration time by considering online monitoring system for it and FLISR functions in AEDS. In this paper, minimizing the total cost of AEDS is determined as objective function considering total customer interruption cost, total cost of energy not supplied, total cost of prevented maintenance actions, total corrective maintenance actions cost implemented in the AEDS and total cost of implementing online monitoring for AEDS's component in maintenance scheduling. The proposed framework is applied in two different cases, Case I is maintenance scheduling without online monitoring system and Case II is maintenance scheduling with online monitoring system. The aforementioned cases are implemented in an IEEE Test System as well as a real scale distribution network. Moreover, several sensitivity analyses are implemented for indicating the efficiency of the proposed model. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
4. Coordinated Planning of Electric Power and Natural Gas Distribution Systems With Refueling Stations for Alternative Fuel Vehicles in Transportation System.
- Author
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Shao, Chengcheng, Li, Ke, Hu, Zechun, and Shahidehpour, Mohammad
- Abstract
The alternative fuel vehicles (AFVs) which include electric vehicles (EVs) and natural gas vehicles (GVs) have gained much attention in recent years for delivering a clean and low-carbon urban mobility. The AFV development is promoting the coordination among electric power, natural gas, and transportation (ENT) networks. This paper proposes a coordinated planning method for investment on and operation of emerging urban energy infrastructures. The sites and sizes of refueling stations are optimized along with the expansion strategies for electric power distribution network (PDN) and natural gas distribution network (GDN). First, AFV refueling demands are analyzed according to the refueling station constraints and options, and transportation network (TN) constraints. Second, the coordinated planning model for PDN and GDN is formulated along with respective operation constraints in PDN, GDN, and TN. An efficient MILP solution method is developed for the proposed optimization problem. Finally, several case studies verify the effectiveness of the proposed model and its solution method. Compared with existing solutions, the proposed panning method offers a more accurate AFV refueling demand model with various refueling options. It is demonstrated that the coordinated planning can reduce investment and operation costs of urban energy infrastructures by exploring the pertinent interactions among constrained PDN, GDN, and TN. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
5. A Reliability-Based Method to Quantify the Capacity Value of Soft Open Points in Distribution Networks.
- Author
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Sarantakos, Ilias, Zografou-Barredo, Natalia-Maria, Huo, Da, and Greenwood, David
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ELECTRICAL load ,DISTRIBUTED power generation ,ELECTRIC power distribution ,REACTIVE power ,REDUNDANCY in engineering ,POWER resources - Abstract
Soft open points (SOPs) are power electronic devices which provide interconnection between two feeders in place of normally open points in electricity distribution networks. SOPs can continuously control active power flow between feeders and inject reactive power controllably at both nodes, which can be used to provide substantial capacity support to the system. This paper provides a reliability-based method to quantify the capacity value (the additional load which can be accommodated without reducing reliability) of SOPs using the Effective Load Carrying Capability method within a Monte Carlo Simulation (MCS). Optimization of post-fault active/reactive power injections by SOPs to minimize energy not supplied is formulated (directly in matrix form) as a second-order cone programming problem. This results in very low computational times which enables embedding of the optimization problem within the MCS. The proposed methodology is applied to a modified real-world distribution network considering three different SOP sizes (5 SOPs totalling 2.5, 5, 10 MVA) across three redundancy levels (N-1, N-0.75, N-0.5), and on an unbalanced network with distributed generation. Results demonstrate capacity values ranging from 2.4–12.84 MVA. When operating under a relaxed redundancy level, the capacity value of a given SOP capacity can more than double relative to N-1. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
6. A Fast Actuation Mechanism and Energy-Effective Driving Method for Pulse-Closers.
- Author
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Yoon, Joanne, Jung, Raehun, Kim, Young-il, Ye, Sung-Joon, and Bang, Young-bong
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ELECTRIC power distribution ,MAGNETIC actuators ,ELECTRIC currents ,ELECTRIC lines ,FAULT currents - Abstract
When a recloser detects fault currents in electric power distribution lines, it breaks the line and then restores the line after several fault tests. To check whether fault remains, the recloser performs CO operations (opening the contacts after reclosing them for a while). In this operation, the fault currents flow into the line, potentially causing damage to equipment connected to the line. Therefore, reducing the current-carrying time during the fault test is desirable, but this reduction is difficult because of the slow actuation mechanism of reclosers. In this article, a novel actuation mechanism combining a permanent magnetic actuator (PMA) and a solenoid actuator (SA) is proposed. During the CO operations for the fault tests, the proposed mechanism can rapidly break the closed contacts by hitting the moving contact with the SA. To increase the energy efficiency of the actuation mechanism, a distinctive PMA driving method is also proposed; it weakens the strong holding force of the PMA using assistive magneto-motive force (MMF). The structure and configuration of the proposed mechanism are explained. The performance of the mechanism and the effectiveness of the driving method are studied through cosimulations. Finally, a prototype is developed, and its practicality is verified through experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
7. Power Factor and Reactive Power in US Residences – Survey and EnergyPlus Modeling
- Author
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Abdullah Al Hadi, Hope C. Anderson, Dan M. Ionel, and Evan S. Jones
- Subjects
Electric power system ,Electric power distribution ,business.industry ,Computer science ,HVAC ,Systems architecture ,Metering mode ,Power factor ,AC power ,business ,Energy (signal processing) ,Reliability engineering - Abstract
Electric power systems are experiencing a growing number of electronic loads in the residential sector as modern appliance technology progresses, and it has become increasingly more important to consider the total power factor (PF) of residential communities. This paper provides a survey based on literature and publicly available information of typical appliance PF values and effects at the residential level as well as a discussion on appliance energy use and corresponding operation schedules. A procedure for the calculation of equivalent PF is proposed and exemplified with minutely experimental data at 15-minute and hourly time intervals, which correspond to smart metering and traditional practices, respectively. The application of the proposed equivalent PF procedure in coordination with building energy modeling, may, in principle, be employed to determine PF for entire communities at an aggregated level. The paper includes a proposal to simulate reactive power through an approach that utilizes EnergyPlus, a building energy modeling software. Such simulation capability could facilitate improved planning for compensation implementation both in electric power distribution networks and in individual residences, which offers significant opportunity for energy savings.
- Published
- 2021
8. Adaptation of DER Control Schemes and Functions During MV Network Back-up Connection
- Author
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Miadreza Shafie-khah, Chethan Parthasarathy, Hannu Laaksonen, and Hosna Khajeh
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Electric power distribution ,Electric power system ,Computer science ,business.industry ,Distributed generation ,Distributed computing ,Adaptive system ,Islanding ,Topology (electrical circuits) ,business ,Network topology ,Active Network Management - Abstract
In the future, active network management (ANM) and adaptive distributed energy resources (DER) control schemes will be increasingly required to fulfill growing power system resiliency and renewable generation integration needs. As part of future ANM schemes more frequent electricity distribution network topology changes could be utilized to improve the electricity supply reliability. However, these topology changes may require DER control methods and functions adaptation accordingly in order to maintain feasible power quality, voltage level and supply reliability in the distribution network. This paper presents a real-life case study from the needed adaptation of DER control schemes and functions after MV distribution network topology change from normal to back-up connection. The focus in the studied case is on MV network connected wind turbine (WT) control scheme adaptation after the topology change based on real measured data from the WT. In addition, the paper presents also simulations from potential future scenarios with centralized and distributed battery energy storage systems (BESSs) which could be also simultaneously utilized for the provision of local and system-wide services.
- Published
- 2021
9. A truly universal bridgeless single-stage soft-switching AC-DC converter for EV on-board charging application
- Author
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Deepak Gautam, Chris Botting, Wilson Eberle, and Peyman Amiri
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Electric power distribution ,Three-phase ,business.industry ,Single stage ,Computer science ,Diode bridge ,Electrical engineering ,Topology (electrical circuits) ,Converters ,business ,Thermal conduction ,Dc converter - Abstract
With accelerated adoption of long range electric vehicles (EVs) lightweight and highly efficient on-board chargers (OBCs) are desirable. At the same time, development of OBCs capable of operation with single and three phase (truly universal) input offers the most versatile charging solution to EV owners regardless of their access to the electricity distribution network. In this work, use of two bridgeless current-fed push pull converters with active clamp is proposed as a truly universal bridgeless single-stage AC/DC converter for on-board charging application. The building blocks of the proposed topology achieve soft-switching and operate in continuous conduction mode with constant switching frequency. The diode bridge is eliminated at the AC input, which results in a simpler thermal management and significant savings in conduction losses. Principle of operation for the proposed converter and details of the proposed control scheme are illustrated in this paper. Proper operation of the converter and effectiveness of the control are verified through PSIM simulation for a truly universal 360V 5.4 kW single stage OBC.
- Published
- 2022
- Full Text
- View/download PDF
10. A Deeper Analysis about the Impact of Prosumers on Power Losses in Low Voltage Microgrids
- Author
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Gheorghe Grigoras, Mihai Gavrilas, Bogdan-Constantin Neagu, Mihai-Andrei Luca, and Ovidiu Ivanov
- Subjects
Electric power distribution ,business.industry ,Computer science ,Scalability ,Optimal allocation ,AC power ,Modular design ,business ,Low voltage ,Automotive engineering ,Power (physics) ,Renewable energy - Abstract
The pressure of climate change and the need for the adoption of renewable sources have led to a strong development of technology within microgrids (μG). The modular and scalable nature presents opportunities for the development of a new class of users in μG (i.e. the prosumers). The large-scale integration of small-scale renewable energy sources (SSRES) creates challenges for today's classic electricity distribution networks. The paper proposes a simulation method for optimal integration of prosumers to minimize active power losses in μG. For a deeper analysis regarding the influence of the prosumers on the μG power losses, 24 hour real load consumption and generation profiles are used. The study's findings show that a more effective μG operation by the optimal allocation of the PV panels on the μG can decrease the active power losses up to 35% in a day.
- Published
- 2021
11. Probabilistic Distributions for Modelling Seasonal Load Profiles of Commercial Areas in South Africa
- Author
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Kgaogelo Mampa and Akintunde A. Alonge
- Subjects
Normal distribution ,Electric power distribution ,Electricity generation ,business.industry ,Climatology ,Log-normal distribution ,Environmental science ,Distribution (economics) ,Electricity ,Time series ,business ,Load profile - Abstract
One of the most significant commodities of today’s world is energy. Energy usage depends on various factors such as season, day of the week, temperature etc. It is imperative that the distribution, transmission, and generation of electricity is effective while equally producing required results to electricity customers. With an expectation for increasing power outages in South Africa in the nearest future, there is a renewed focused on electricity distribution and consumption. This paper examines the electric load profile at a commercial location in Johannesburg, South Africa, for which the overall dataset (in KWh) is classified into four seasonal regimes: summer, spring, winter, and autumn. Two probabilistic models – normal and lognormal distributions – are applied to investigate the medium-term behaviour of the time series dataset over a period of two years, between 2019 and 2020. Results from this investigation suggest that normal distribution gives a better approximation to the seasonal datasets, except during the spring season. The lognormal distribution is observed to give minimal fitting errors during the spring season. Additionally, the load profile during summer and spring seasons are observed to exhibit similar characteristics, likewise, both autumn and winter seasons are found to exhibit the same trend for the same period.
- Published
- 2021
12. Generation of Non-Isolated Radial Configuration in Distributed Power Systems
- Author
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Aldir Silva Sousa, Ricardo A. L. Rabelo, and Enio Rodrigues Viana
- Subjects
Distribution system ,Electric power system ,Electric power distribution ,Work (thermodynamics) ,Robustness (computer science) ,Computer science ,Distributed power systems ,business.industry ,Electronic engineering ,Radiance ,business ,System protection - Abstract
Electric power distribution systems are often configured to operate radially and without islands. Radiance is important for the sake of improving system protection. Also, for legal reasons, distribution systems should not operate with islands. In this work, we present a procedure for generating radial configurations. In addition, the methodology proposed in this paper is able, through switches, to detect and remove configurations with islands. Tests were carried out in several systems and, after analysis, we can verify the efficiency and robustness of the proposed methodology even for large systems.
- Published
- 2021
13. An IoT-Based Smart Energy Meter With Real-Time Power Tracking System: A Review
- Author
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Jabed Ali, Md. Nur Islam Rimon, Fatema Tauze Zohora Saima, Md. Hasibul Islam, and Touhidul Islam Talukder
- Subjects
Electric power distribution ,Microcontroller ,Distribution board ,business.industry ,Computer science ,Electricity meter ,Electrical engineering ,Electricity ,business ,Grid ,Wireless sensor network ,Solar power - Abstract
Smart metering is a modern topic with rapid and continuous development. Smart metering offers the advantages of software running systems in measuring and managing the building utilities such as energy, water, gas, etc. The design and development of an IoT-based smart energy meter with a realtime power monitoring system device has been reported in this study paper. System idea has been designed that will be used to monitor electrical parameters such as voltage, current, and power of household appliances with grid and solar power. The proposed system consists of a smart sensing unit that will detect the home electrical appliances used for daily activities by following different tariff rates. It will reduce costs for the consumers and thereby improve grid stability. For electricity tracking, there will be voltage and current sensors, microcontrollers, and Wi-Fi modules. Consumers will be able to access to see the power ratings through a smartphone app from anywhere and anytime. Finally, solar and grid power will be connected to the device as a power source. Furthermore, this measured power would be delivered directly to the electricity distribution office. They will even be able to make the electric bill from the office without going from one home to another. The power consumption will be tracked by the main distribution board in this research study.
- Published
- 2021
14. Multi-Objective Particle Swarm Optimization for Harmonic-Constrained Hosting Capacity Maximization and Power Loss Minimization in Distorted Distribution Systems
- Author
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Heba T. Ellamsy, Ziad M. Ali, Ahmed Ibrahim, and H E Abdel Aleem Shady
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Electric power distribution ,Mathematical optimization ,Total harmonic distortion ,business.industry ,Computer science ,Harmonic ,Particle swarm optimization ,Power factor ,Maximization ,AC power ,business ,Power (physics) - Abstract
The uncontrolled addition of renewables may result in complications in power grids unless they are correctly allocated. The problems happen when the rating of the connected renewables surpasses the maximum permissible level of renewables penetration, and this occurs when the system exceeds its maximum hosting capacity (HC) edge. In this paper, multi-objective particle swarm optimization (MOPSO) is employed for harmonic-constrained hosting capacity (HC-HC) maximization and active power loss (P loss ) minimization in harmonically distorted distribution systems. Type C filters are optimally designed to mitigate harmonic distortion. IEEE 519 recommendations are taken into account to achieve the acceptable harmonic distortion limits. Correction of the true power factor of lumped loads and improvement of the voltage at the point of common coupling are considered in accordance with the Egyptian electricity distribution code. The results obtained show the effectiveness of the proposed type C filters.
- Published
- 2021
15. Design of a Domestic Controlled Voltage Stabilizer
- Author
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Abdoulaye Kebe, Ibrahima Gueye, and Moustapha Diop
- Subjects
Electric power distribution ,Work (electrical) ,business.industry ,Computer science ,Robustness (computer science) ,Electric power ,Voltage regulator ,Stabilizer (aeronautics) ,business ,Automotive engineering ,Voltage ,Power (physics) - Abstract
This paper aims to design a controlled voltage stabilizer to protect domestic appliances from voltage dips in electrical power distribution. Voltage dips are recurrent and become a concern for distributors and consumers. Voltage dips affect the power quality and can have a negative impact on the proper functioning of domestic appliances and other sensitive electronic equipment. Today, this problem has become central and recent measurements show that voltage dips can reach 35 to 40 % in some regions of Senegal. Therefore, this work is mainly focused on the design of a single-phase CVS, using control methodologies based on PI controllers that can effectively handle large voltage dips. The proposed controlled voltage stabilizer consists of a fully controlled AC-AC power converter, based on a single-phase boost rectifier connected to a single-phase PWM inverter with control laws. The design and the control laws adopted were carried out taking into account the characteristics of the electric power distribution, as well as the domestic loads. The robustness and effectiveness of the controlled voltage stabilizer are verified by carrying out simulations in the Matlab simulink environment in various operating cases using real measurements of voltages with different types of electrical loads. Simulation results confirm the effectiveness and robustness of the proposed stabilizer. Furthermore, it enables the protection of domestic appliances by keeping the voltage level stable within a specified range around the rated value regardless of voltage dips.
- Published
- 2021
16. Design and Modeling of a Filter Assisted 6-Pulse VSC-IGBT Based D-Statcom for Reactive Power Compensation
- Author
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Biswabijet Panigrahy, Krishna Dutt, Radheshyam Saha, Bushra Arif, and Ritul Panchal
- Subjects
Electric power distribution ,Total harmonic distortion ,Electricity generation ,Computer science ,business.industry ,Power electronics ,Electronic engineering ,Voltage source ,Insulated-gate bipolar transistor ,AC power ,business ,Compensation (engineering) - Abstract
Utilities are looking for cost-effective solutions to improve the grid's power quality and stability. Applications of FACTS devices provide a popular and proven solution to reactive power compensation, mitigating grid instability, improving power quality and voltage stability. Amongst a plethora of FACTS devices, shunt controllers are the most sought-after power controllers in which the power electronics-based Static Synchronous Compensators or STATCOM is the popular state-of-the-art technology. The increasing penetration of distributed RE (DRE) based electricity generation plays a crucial role in supplying power to loads in remote areas, especially where the main grid system is inaccessible. Such areas are frequently suffering the problems of reliable power supply, power quality, and voltage instability. The Utilization of smart inverters based on dynamic reactive power compensation by Distributed-STATCOM (D-STATCOM) has enabled to qualitatively improve the end-user requirements in the electricity distribution system. The design and behavior of a simple filter assisted D-STATCOM for reactive power compensation during variation of inductive loads is the topic of this paper. A cost-effective ±200kVAr D-STATCOM armed with a novel output filter and improved PI controller employing the pulse width modulated (PWM) technique to IGBT based Voltage Source Converter is proposed to compensate reactive power requirement of loads and to improve transient and dynamic stability, limiting harmonic distortion within standard IEEE-519 limits. The proposed STATCOM design is simulated in Simulink/MATLAB, which confirms its satisfying dynamic reactive power compensation capabilities and low level of harmonic distortion.
- Published
- 2021
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