Electrical Distribution System Research Articles

Verification of a Modeling Toolkit for the Design of Building Electrical Distribution Systems

DC electrical distribution systems offer many potential advantages over their AC counterparts. They can facilitate easier integration with distributed energy resources, improve system energy efficiency by eliminating AC/DC converters at end-use devices (e.g., laptop chargers), and reduce installation material, time, and cost. However, DC electrical distribution systems present additional design considerations, largely resulting from potentially greater magnitude and variation in cable losses. Modeling and simulation are rarely used to design such systems. However, the greater dependency of DC system energy efficiency on design choices such as distribution voltages, architecture, and integration of PV and BESS suggests that modeling and simulation may be required. Such system performance analysis is currently not a standard practice, in part due to limited availability and validation of capable software tools. This paper characterizes the accuracy of a Modelica-based Building Electrical Efficiency Analysis Model (BEEAM) toolkit, as a precursor for validating its use to perform system performance analysis and inform design decisions. The study builds upon previous verification research by characterizing complete systems comprised of commercially available equipment, and providing a more detailed analysis of simulation results. Five lighting systems with varying electrical distribution architectures were designed using market-available equipment, installed in a laboratory environment, modeled using BEEAM, and simulated using three Modelica integrated development environments (IDEs). Simulated and measured results were compared to characterize toolkit accuracy. Initial results revealed that simulated performance was mostly within ±5% of measured system-level and device-level performance. While simulation results were not found to be dependent on the IDE, some Modelica compiler interoperability issues were identified. Although the BEEAM toolkit showed promise for the targeted use case, further work is needed to determine whether the demonstrated 5% accuracy is sufficient for making real-world design decisions, and for BEEAM to advance from an interesting research tool to one that can impact real-world building projects.

A Risk-Based Planning Approach for Sustainable Distribution Systems Considering EV Charging Stations and Carbon Taxes

Adopting distributed energy resources (DERs) is the key to a low-carbon future in electrical distribution systems (EDS). However, integrating DERs increases the uncertainties in the distribution system expansion planning (DSEP). Thus, the long-term DSEP faces a planning risk brought by the uncertainty of demand, electric vehicle (EV) demand, renewable production, and energy prices. Therefore, this work proposes a novel model for the multi-period planning of EDSs and DERs considering conditional value at risk (CVaR) to manage fluctuations in generation cost and carbon emissions. The proposed mathematical model aims to minimize the net present cost related to investment, operation, and risk. Unlike previous approaches, uncertain behavior of demand growth per planning period is addressed, and the risk is evaluated from two perspectives: planning costs and carbon taxes. Investments in substations, lines, renewable distributed generation, EV charging stations, and energy storage systems are considered. The uncertainties associated with the variability of renewable generation and demand are modeled through a set of scenarios. Finally, the model was evaluated using the 24 and 54-bus EDS. Thus, the proposal is a flexible tool that can be used for different purposes (e.g., carbon taxes, budget limits).

Use of Plat-Bar Electrode Media to Detect Partial Discharge in Epoxy Resin Materials on PCB Surfaces

The electric power system must have a protection system with reliable electric power isolation, so that the supply of electrical energy works properly and optimally. There are several kinds of disturbances in the electric power distribution system, one of which is a partial discharge. This study aims to investigate the effect of plate-rod electrodes on partial discharge, partial discharge voltage limits in solid insulation, and the characteristics of partial discharge in electrode media, and waveforms in partial discharge detection sensors. After conducting research, it was found that in the plate-rod type electrode media, the PDIV voltage appeared earlier than the plate-plate electrode media due to the cross-sectional area of the electrode media. And the limit of the pre-discharge voltage of PCB type solid insulation on the plate-bar electrodes is at a voltage of 1.3 kV. Several indicators to determine the characteristics of the partial discharge are background noise off (BGN off), background noise on (BGN on), partial discharge inception voltage (PDIV), and partial discharge voltage. After being examined, the value of each partial discharge detection voltage was obtained at negative and positive polarity voltages on the electrode plates and plate needles respectively 2.85 kV, 2.95 kV and 1.32 kV, 1.57 kV.

Enhancing Service Restoration in Tanzanian Power Grid using Internet of Things Sensors and Renewable Energy Sources

The increased dependence on the electric power grid, coupled with the increasing number of new customers, motivates the need to improve the reliability and resilience of the electric distribution systems. Modern distribution systems are becoming more resilient against power outages due to the increasing integration of Distributed Energy Resources (DERs) and the availability of efficient mechanisms for load shedding. Several studies considered fault detection and Service Restoration (SR) as separate problems without considering the implementation feasibility of integrating both solutions. To ensure the resiliency in the power system, it is important to have proper mechanisms which integrate sensing, detection, and SR as one problem while considering the load shedding and DER for improved capacity. Hence, this study proposed an IoT-based-sensor network framework with an enhanced algorithm coupled with a Binary Bat metaheuristic algorithm for SR integrating sensing, detection, and restoration. The proposed algorithms have been tested in Tanzania's electrical distribution network, considering the inclusion of DERs and load shedding. The results showed that DERs' size and locations significantly impact restoration schemes' performance with a power loss reduction of 74%. Therefore, efficient SR schemes should consider optimal DERs placement and a combination of load shedding and DERs integration for improved performance.

Modelling and Allocation of Hydrogen-Fuel-Cell-Based Distributed Generation to Mitigate Electric Vehicle Charging Station Impact and Reliability Analysis on Electrical Distribution Systems

The research presented in this article aims at the modelling and optimization of hydrogen-fuel-cell-based distributed generation (HFC-DG) to minimize the effect of electric vehicle charging stations (EVCSs) in a radial distribution system (RDS). The key objective of this work is to address various challenges that arise from the integration of EVCSs, including increased power demand, voltage fluctuations, and voltage stability. To accomplish this objective, the study utilizes a novel spotted hyena optimizer algorithm (SHOA) to simultaneously optimize the placement of HFC-DG units and EVCSs. The main goal is to mitigate real power loss resulting from the additional power demand of EVCSs in the IEEE 33-bus RDS. Furthermore, the research also investigates the influence of HFC-DG and EVCSs on the reliability of the power system. Reliability is crucial for all stakeholders, particularly electricity consumers. Therefore, the study thoroughly examines how the integration of HFC-DG and EVCSs influences system reliability. The optimized solutions obtained from the SHOA and other algorithms are carefully analyzed to assess their effectiveness in minimizing power loss and improving reliability indices. Comparative analysis is conducted with varying load factors to estimate the performance of the presented optimization approach. The results prove the benefits of the optimization methodology in terms of reducing power loss and improvising the reliability of the RDS. By utilizing HFC-DG and EVCSs, optimized through the SHOA and other algorithms, the research contributes to mitigating power loss caused by EVCS power demand and improving overall system reliability. Overall, this research addresses the challenges associated with integrating EVCSs into distribution systems and proposes a novel optimization approach using HFC-DG. The findings highlight the potential benefits of this approach in terms of minimizing power loss, enhancing reliability, and optimizing distribution system operations in the context of increasing EV adoption.

Optimization methods to solve the set covering problems

Phasor Measurement Unit Placement aims to decrease the cost this phasor equipment while maintaining the observability of the electrical distribution systems. This placement can be modeled as a set covering problem. Synchronized phasor data provides electrical systems’ information with higher quality and frequency than Remote Terminal Units. These data enable the implementation of faster than real-time state estimators. Thus, supervisory control and data acquisition systems can be replaced by automatically monitored systems that add reliability, efficiency, and resilience to smart grid systems. Due to the flexibility and large-scale in the distribution systems, heuristic methods have frequently been applied to this placement problem. Since the use of Chemical Reaction Optimization (CRO) algorithm is not recurrent, we have decided to implement it together with a topological system observability analysis. Initial population creation, parameterization, elementary reactions of CRO, and local search strategies are presented in this study. Computational results were performed in IEEE power system test cases. The optimization method proposed has obtained optimal results at a lower computation time than the literature. To test in large-scale, we have applied another optimization method to Set Covering Problems from Beasley library, with different parameters. However, the results were not satisfactory indicating that the CRO might not be suitable to some large-scale instances of the Set Covering Problems this library. In this case, further studies are required.

Addressing Power Loss and Voltage Profile Issues in Electrical Distribution Systems: A Novel Approach Using Polar Bear Gradient-Based Optimization

Energy is an essential commodity for everyone, with electrical energy being the most preferred form. Unfortunately, non-renewable energy resources are gradually depleting, and renewable energy sources take several years to establish. To mitigate this problem, technology has shifted from non-renewable energy sources to electrical devices and machines, including household appliances like washing machines and air conditioners. However, the generation of electricity is still inadequate to meet the growing demand. This leads to two major problems: high power loss and poor voltage profile, making it difficult for power distribution companies to ensure a consistent and reliable power supply. This paper aims to address the reduction and minimization of power losses by adjusting distribution side transformer tap settings using the polar bear gradient-based optimization. The proposed approach uses the 14-bus system as a reference and calculates losses for this system using the backward-forward sweeping technique. The results are compared with standard PSO algorithm; the proposed strategy shows superior results.

Assessment of topological boundaries for microgrids in an active power distribution network during emergencies

Microgrid (MG) operation has become an intriguing possibility to enhance the sustainability, reliability, and resilience of electricity distribution systems in emergencies. However, identifying suitable physical boundaries of MGs from an active power delivery infrastructure is a highly challenging task. This study describes a novel approach for determining the topological boundary of multiple MGs to restore power supply in a power distribution system during the unavailability of grid power supply. This method tries to enhance the self-adequacy of the MGs by increasing power flow within the MG boundaries. In this context, possible demand at the nodes of the power delivery infrastructure during an emergency is anticipated by an autoregressive integrated moving average (ARIMA) and long short-term memory (LSTM) network-based time series forecast models. A modified backward-forward sweep (MBFS) power flow analysis, tailored for islanded mode, is employed to assess the power flow status in the MGs during emergencies. The MGs are supplied with locally available dispatchable distributed generators (DDGs). A particle swarm optimization (PSO) algorithm intertwined with the MBFS power flow method has been employed to determine the boundary of MGs by identifying minimum power flow line in the shortest path between the consecutive DDGs. Further, this study demonstrates the evaluation of the shortest path between paths between the consecutive DDGs with the help of a breadth-first search (BFS) algorithm. The proposed strategy has been tested on a modified 33-bus, 69-bus and 118-bus power distribution test systems. The experimented results are verified with the results obtained from similar existing approaches to explore the opportunities in the proposed methodology.

Overcurrent and ground fault relay protection settings at tranformator-1 150kV/20kV Braga substation

The occurrence of a malfunction at the substation results in power outages and losses in the electrical energy distribution system to consumers. Many tests are carried out to see the performance of the protection system, including the parameters of the over current relay (OCR) and ground fault relay (GFR) in the electrical energy distribution system. This research aims to analyze OCR and GFR values, analyze OCR setting, drop-off, and pick-up values, and analyze OCR time characteristics using DigSilent Power Factory 15.1 software based on existing equipment specification data at the Braga substation. The results show an OCR accuracy level of around 94% on the 20 kV and 150 kV sides. Meanwhile, 92.39% on the 20 kV GFR side and 94.87% on the 150 kV side. The setting value for the pick-up current is 0.92 A on the 20 kV side of the GFR and the drop-off current is 0.85 A on the 150 kV side with a pick-up current of 0.39 A and a drop-up current of 0.37 A. Setting a value on the 20kV side is greater than on the 150 kV side due to the difference in current transformer ratio values. The simulation results show that the OCR and GFR characteristic curves on both sides meet the criteria for a protection system with good performance.

Low-carbon electrification as a multi-system transition: a socio-technical analysis of Norwegian maritime transport, construction, and chemical sectors

Electrification of end-use sectors is widely seen as a central decarbonisation strategy. However, the process of electrification is rarely discussed beyond electric end-use technologies such as electric vehicles or heat pumps. While electrification of end-use sectors is about new types of consumption, it also requires new technological interfaces with the electricity system. The paper provides a first conceptualisation of electrification as a multi-system interaction process, involving changes in both end-use sectors and in the electricity system. Electrification is thought to involve two core processes: (1) transitions in systems where electric niches challenge fossil energy regimes, and (2) reconfiguring patterns of multi-system interactions across production, distribution, and use of electricity. Through a case study design, we compare three sectoral cases that differ substantially in degrees and speed of electrification: ferries, construction sites and ammonia production. We explain these differences by analysing how the actors, technologies and institutions in each system shaped both the diffusion of electric end-use technologies and the interactions with the electricity distribution system. We find that the speed and ease of electrification depend on varying mixes of technological, actor, and institutional change processes. The severity and pervasiveness of grid connection challenges are arguably the most important finding. Grid connection challenges were significant in all three cases and continue to hamper electrification in two cases. Based on those findings, we conclude that grid capacity is increasingly problematic. Electricity system actors are overwhelmed with new demand, resulting in long lead times. And, they are further constrained by institutions that were designed to optimise for the efficient operation of existing assets rather than to innovate and transform electricity grids.

Coordination of resilience interventions by proactive consumers and the supplying utility

Pursuing resilience enhancement, we propose a hierarchical decision-making framework for proactive consumers and the supplying utility interacting through an electricity distribution system. Such decision framework enables identifying solutions that are optimal for both the leading partner, the electric utility, and the other agents, proactive consumers and non-proactive consumers, that react to the decisions of the leading agent. Resilience improvement interventions include installing batteries and undergrounding distribution lines. The proposed technique can be helpful to distribution system planners, who can use it to optimally coordinate the resilience enhancement investments by the electric utility and proactive consumers. We analyze cases pertaining to realistic distribution systems.

Implementation of Power Factor Correction using Asynchronous Boost Converter on Single Phase Full-Bridge Diode

In various industrial applications, the use of a power supply that uses a conventional diode single-phase rectifier topology results in high harmonic values in the electricity distribution system. One of the real impacts of this harmonic value is the heating of the electric power system equipment and power losses. High rms current values due to harmonics often cause problems in protection settings in addition to efficiency problems. The percentage value between the total harmonic component and the fundamental component is called THD (Total Harmonic Distortions). Therefore, in this study an asynchronous dc-dc boost converter is connected to the output side of a single-phase diode rectifier which is capable of improving power factor and low harmonics. So that a THD value of less than 15%, PF (Power Factor) = 0.92-1 and a sinusoidal input current can be obtained. The implementation results show that the PFC (Power Factor Correction) method can work well on single-phase diode rectifiers.

Geometric Deep-Learning-Based Spatiotemporal Forecasting for Inverter-Based Solar Power

Conventional power grids dominated by synchronous generators gradually shift to variable renewable-energy-integrated grids. With the growth of building-level photovoltaic (PV) panels and other inverter-based resource (IBR) deployments in recent years, market retailers and distribution operators have had to deal with the additional operational and management challenges posed by unobserved energy flow if its behind-the-meter (BTM) configuration. Also, the intermittent and stochastic nature of IBR-based solar power introduces uncertainty into the net load forecasting of electric distribution systems. Hence, management and control with high uncertainty in load prediction due to unobservable PV is a technical challenge. This article presents deep-learning-based algorithms for BTM PV power generation using a limited number of sensors in a given distribution system and extending to adjacent geographical areas. The proposed BTM PV forecasting method is based on geometric deep learning—a spatiotemporal graph neural network by processing the relationship between data in a non-Euclidean graph structure. The predictions of short-term BTM PV are aggregated with loss estimation at the data aggregation point with the net load forecasting to compute the true load forecasting with superior performance. The developed BTM PV forecasting method significantly improved true load forecasting results, which were validated and analyzed using a collection of actual BTM PV and load measurements in a test distribution feeder.

High-Performance Megawatt-Scale MVDC Zonal Electrical Distribution System Based on Power Electronics Open System Interfaces

Integrated Power and Energy Systems (IPESs) will play a critical role in supporting future complex electric ship operations. In particular, flexibility is required to exploit shipboard energy sources and storages for multiple ship functions, supporting a highly dynamic electrical power use. To this aim, the Medium Voltage DC (MVDC) electrical power distribution has been conceived to provide requested power flexibility, along with other expected advantages in terms of functional integration and ship design. For complex and high-performance ship power systems, the Zonal Electrical Distribution System (ZEDS) concept has been proposed to maximize MVDC capabilities even under extremely demanding operational conditions. This paper presents a megawatt-scale test facility of a MVDC ZEDS developed and built in Trieste, Italy, based on power electronics open system interfaces. The demonstrator is described in its power and control design architectures and capabilities. In particular, a successful MW-scale test is presented, to show ZEDS capability in supporting large and fast load variations, while maintaining acceptable MVDC voltage tolerances.

Combinatorial optimization algorithm with coordínate search method to lócate and size distributed generation plants in a radial distribution electrical system

Combinatorial optimization algorithm with coordínate search method to lócate and size distributed generation plants in a radial distribution electrical system

Interline Unified Power Quality Conditioner for Enhancing Power Quality using FOFPID-based Interleaved CUK Converter

Electrical distribution systems face increased non-linear loads due to using power electronics for the converters. Due to these non-linear loads, the system exhibits PQ problems in the distributed feeders. To enhance PQ problems in the dual feeder, fractional order fuzzy proportional integral derivative controller (FOFPID) is introduced with interline unified power quality (IUPQC) conditioner. IUPQC conditioner includes a distribution static compensator (DSTATCOM), dynamic voltage restorer (DVR) and interleaved cuk converter (ICC). DSTATCOM and DVR are used for compensating the voltages and current in the dual feeders (feeder-1 and feeder-2). Also, ICC monitors the switching between the DSTATCOM and DVR compensators by providing proper power flow. Moreover, the FOFPID controller regulates an input supply from both feeders. The simulation is performed through MATLAB/Simulink platform, demonstrating the robustness of a proposed FOFPID with an IUPQC controller. The performance of a proposed controller is analyzed through two cases for both feeders. Furthermore, the total harmonic distortions (THD) are calculated for the feeder parameters. The proposed FOFPID with IUPQC controller also maintains stability in a dual feeder. Therefore, the entire response shows the functionality and feasibility of a proposed controller.

SISTEM PROTEKSI DAN MONITORING KESEIMBANGAN BEBAN TIGA FASA PADA JARINGAN DISTRIBUSI TEGANGAN RENDAH MENGGUNAKAN MIKROKONTROLER BERBASIS IOT

Three-phase electrical systems are widely used by industrial consumers because of their large power requirements. The 3-phase system is more economical in the delivery of electrical power than the single-phase system because the conductor used is smaller for the same power. A 3-phase system is said to be balanced if the load used is also balanced between the three R-S-T phases. However, in practice the balance of the three phases is very difficult to achieve because the electrical load of each house or industry is not necessarily identical. As a result of this imbalance between the R-S-T phases can cause damage to electronic equipment that uses 3-phase electricity if used continuously.According to PUIL 2011 the unbalance distribution system includes an unbalanced current between phases with provisions up to a tolerance value of 10%. In a 3 phase electrical distribution system, there will often be load imbalances. This is due to the addition or use of electrical loads that do not pay attention to the imbalance in the system.For this reason, in this study, a tool that uses the PZEM-004T sensor, Wemos D1 mini module, and Android Studio was created which can allow for remote monitoring using electronic devices that have installed applications that have been created. when an error occurs, the "reset" button on the monitoring application is used to reset the protection to restore the device. The current difference in the avometer is 1.48A and the sensor is 1.46A and the current flowing to the load is written 1.88A. The contactor works when the relay receives a command from the Arduino nano with a fast time, namely: 1.60 seconds on the first try, 1.72 seconds on the second experiment, and 1.68 seconds on the third experiment.

Advances in the Co-Simulation of Detailed Electrical and Whole-Building Energy Performance

This article describes recent co-simulation advances for the simultaneous modeling of detailed building electrical distribution systems and whole-building energy performance. The co-simulation architecture combines the EnergyPlus® engine for whole-building energy modeling with a new Modelica library for building an electrical distribution system model that is based on harmonic power flow. This new library allows for a higher-fidelity modeling of electrical power flows and losses within buildings than is available with current building electrical modeling software. We demonstrate the feasibility of the architecture by modeling a simple, two-zone thermal chamber with internal power electronics converters and resistive loads, and we validate the model using experimental data. The proposed co-simulation capability significantly expands the capabilities of building electrical distribution system models in the context of whole-building energy modeling, thus enabling more complex analyses than would have been possible with individual building performance simulation tools that are used to date.

Impact of Distributed Generation on the Effectiveness of Electric Distribution System Reconfiguration

Distribution system reconfiguration (DSR) is an essential activity in the operation of distribution utilities, usually carried out to lower active power losses and improve reliability metrics. The insertion of distributed generation (DG) units in electric power distribution systems (EPDS) causes the rearrangement of power flows through the conductors and changes the real power losses and voltage profile; therefore, up to a certain point, the insertion of certain quantities of DG may potentially delay or change the reconfiguration strategy of EPDS. This article presents an analysis of the impact of DG, for different locations of the units and different levels of active power supplied by them, on real power losses and on the effectiveness of DSR. The article presents tests with different distribution systems with varying sizes and topologies, showing that the allocation of DG units in buses far from the substation provided the best cost–benefit results. The DSR impact changes depending on the installment location and the generation level of the DG units, corroborating that DSR must be considered and performed using certain criteria, to maximize its efficiency.

Optimizing the hybrid PVDG and DSTATCOM integration in electrical distribution systems based on a modified homonuclear molecules optimization algorithm

AbstractThe increasing use of non‐linear loads in electrical distribution systems (EDS) led to a greater need for reactive power compensation, losses minimization, improved voltage and stability. This paper proposes the optimal integration of hybrid photovoltaic distributed generation (PVDG) and distribution static synchronous compensator (DSTATCOM) into IEEE 33 and 69‐bus EDS. A modified version of homonuclear molecules optimization (mHMO) is developed to determine the optimal allocation of the devices, while minimizing a multi‐objective function (MOF) based on total active power losses (TAPL), total voltage deviation (TVD), and investment cost of integrated devices (ICPVDG and ICDSTATCOM). The primary objective of the mHMO is to enhance the equilibrium between exploration and exploitation in the original HMO by implementing a fresh exploration stage. The effectiveness of mHMO was assessed using CEC17 benchmark functions. The findings demonstrate that mHMO achieved excellent results, including high‐quality solution and a favourable convergence rate. Additionally, results demonstrate that mHMO outperforms its basic version in reducing TAPL by 94.27% and 97.87% for the two EDS, while improving voltage profiles and reducing the cost of integrated devices. This study shows the potential of hybrid PVDG‐DSTATCOM in improving the performance of EDS and highlights the effectiveness of mHMO in optimizing their integration.