Low-voltage Power Distribution Research Articles

A transfer-learning-based robust technique for multi-type fault detection and classification using Hilbert–Huang transform in low-voltage power distribution grids

A transfer-learning-based robust technique for multi-type fault detection and classification using Hilbert–Huang transform in low-voltage power distribution grids

Design of Instrumentation and Control Components of Power Distribution Systems

Introduction. In recent years, the development of high-voltage power systems has received a boost due to the need for infrastructural support for priority development areas. Universal models and algorithms are required to implement processes in power components and identify their optimal parameters. However, there are no such solutions. Accordingly, there are no ready-made subsystems with control and optimization algorithms adequate to the tasks under consideration. The objective of the presented research is to develop an optimization subsystem for the design of control and measurement components of power distribution systems.Materials and Methods. Methods for constructing automated design systems, optimization, system analysis, mathematical modeling, and adaptive control were used. When selecting methods, we proceeded from the fact that the components of power distribution systems consisted of a finite number of elements. The synthesis of a power system includes tens or hundreds of sequential operations. This was taken into account in the developed models and algorithms.Results. The possibilities of managing and monitoring manufacturing processes (MP) for the production of components of low-voltage power distribution systems were shown in terms of checking the operability and correct functioning of processing equipment. A modular structure was created to allow the integration of CAD output files into the manufacturing processes of energy distribution system components. A functional diagram of a subsystem for control and monitoring of the manufacturing processes of the production of components of power distribution systems was developed. The proposed schematic diagram of production control showed how the data collection subsystem, management system, and operating mechanisms were involved in the control of operations. The multi-level optimization module model created within the framework of this research sequentially optimized the service intensity of the i-th block, the input flow separation coefficients, and the priorities of the original data flows that form the input flow of the i-th block.Discussion and Conclusion. The combined application of modeling, system analysis, and optimization methods maintains control of the accuracy of the generated power components. The algorithm for controlling electrical loads opens up opportunities for creating a mathematical model of a power supply system that combines management, control, and monitoring, which ultimately leads to an improvement in the quality of electric power. The solution can be in demand in the development of power systems of priority development areas.

A Novel Control Strategy for Soft Open Point to Address Terminal Voltage Violations and Load Rate Imbalance in Low-Voltage Power Distribution Station Areas.

In low-voltage power distribution station areas (DSAs), sensor devices and communication networks are often inadequate. Therefore, the control strategies mainly used for soft open points (SOPs) based on global information in medium-voltage distribution networks are difficult to be directly applied to low-voltage DSAs. This paper proposes a novel control strategy for SOP that only requires collecting the local information of SOP and the load rate of transformers. It aims to address the issues faced of voltage violations at the end of feeders and the load rate imbalance among adjacent DSAs under the current high penetration of renewable energy sources. In this paper, first, a sensor network consisting of sensor devices located at the transformers and each port of the SOP is introduced for information collection. Then, based on the sensitivity relationship between the node voltage and the injected power, considering capacity and voltage safety constraints, the adjustable range of the active power output for each port of the SOP is derived. According to this range, the operating states of the DSAs are categorized into four scenarios. For each scenario, the adjustment amount of SOP output power is determined to achieve comprehensive regulation of terminal voltage and load rate of all DSAs interconnected by SOP. Finally, the effectiveness of the proposed strategy is verified based on a simulation model of three flexible interconnected DSAs established in MATLAB/Simulink.

Impact of cost-based smart electric vehicle charging on urban low voltage power distribution networks

Impact of cost-based smart electric vehicle charging on urban low voltage power distribution networks

AC Network-Constrained Peer-to-Peer Electricity Market Model in Low-voltage Power Distribution Networks

The rapid growth of Distributed Energy Resources (DERs) and demand response in modern power grids calls for decentralized electricity trading mechanisms to effectively induce and coordinate responses from massive DERs and load entities. This paper proposes a fully decentralized peer-to-peer (P2P) distribution electricity trading mechanism backboned by a modified version of Alternating Direction Method of Multipliers (ADMM). Comparing with the state-of-the-art P2P electricity markets, the proposed electricity trading mechanism comprehensively incorporates power network constraints formulated by an alternating current power flow model. In the proposed method, nodal voltages are designed as the only public variables shared among participants. Privacy of each participant is thus sufficiently preserved without exposing the bid data to the others. Meanwhile, the proposed P2P method can also ensure the global optimality of social welfare in electricity transactions. Comprehensive case studies are carried out using the IEEE 33-node distribution system to demonstrate the feasibility and efficiency of proposed P2P electricity trading mechanism. The results indicate that the proposed model can efficiently integrates network constraints in the market clearing process while maintaining computational performance, ensuring stable convergence regardless of distribution system congestion. The proposed P2P electricity market can achieve global maximization of social welfare, with a relative difference of no more than 5.0% compared to the conventional centralized market. Even in worst-case scenarios, the relative difference remains within 7.32%. Meanwhile, the method accurately accounts for network losses, guaranteeing the feasibility of trading plans within the physical network.© 2017 Elsevier Inc. All rights reserved.

Study on the impact of rooftop solar power systems on the low voltage distribution power grid: A case study in Ha Tinh province, Vietnam

Vietnam has developed solar power very quickly in recent years. However, the integration of the solar power system into a distribution power grid can cause a clear effect on the voltage of the grid. Accordingly, the voltage at the nodes increases significantly because of the appearance of photovoltaic (PV) systems, and it can lead to overvoltage at some load nodes near the solar power source. The impact of solar power stations with distribution power grids depends on the location and operating conditions of the utility grid. Therefore, the study of the impact of rooftop solar power on the distribution grid needs to add actual operating data of the utility grid to achieve a more detailed assessment and reliability. This study analyzed the influence of rooftop solar power on a low voltage distribution power grid in Ha Tinh province, Vietnam with the support of ETAP software. The scenario was calculated for 50% of the power (3-phase) penetration gain of the transformer. Besides, a proposed synthetic solution is a combination of reactive power compensation with a 5kVAr minimum compensation level at many points on the grid and adjustment of the load tap at the appropriate level depending on the load situation of the transformer. Thus, the voltage of the nodes on the power grid is improved, and the power loss is also decreased.

Method of Calculation the Load Rates and the Unbalance Rates of the Current of the Phases in the MV/LV Network of the Sales and Service Center Lemba in Kinshasa

In this article, we discuss the calculation of load and current imbalance rates, which is a steady-state study of the distribution network that consists of determining, for each subscriber station, the operating rate of the installed power transformer and the current difference between two phases of the MV/LV distribution station. Knowing the allowable currents of each low-voltage phase of the subscriber substations from the busbars as well as the rated current of the substations transformer, we can calculate, secondly, the average currents and load factors of the substations including the differences between the currents and their unbalance factors in the low-voltage distribution power lines. The mathematical equations of the electrical quantities of the power system facilitate the evaluation of the performance of the power transformer. These equations confirm that the variation in load ratio and current imbalance of three phases are closely related to the current draw of the allowable loads at each phase.

Behavioral Model of G3-Powerline Communication Modems for EMI Analysis

G3-powerline communication (G3-PLC) is a robust communication protocol originally developed for smart metering in low-voltage power distribution networks. Modeling G3-PLC modems is an essential task to investigate electromagnetic compatibility (EMC) issues related to the coexistence of the PLC signal with the high-frequency noise affecting low-voltage networks, mainly due to the presence of power converters and non-linear loads. Since detailed information on the modem internal architecture is usually not available to the end-user, this work investigates the possibility of developing behavioral (black-box) models of G3-PLC modems, whose parameters can be estimated starting from measurements carried out at the modem output ports. To this end, suitable test benches are set up and used for model-parameter extraction as well as for validation purposes. Experiments have proven that an equivalent representation involving non-ideal voltage sources (i.e., in terms of extended Thevenin/Norton equivalent circuits) is no longer feasible for the transmitting modem, since the presence of a closed-loop control system invalidates the linearity assumption. Hence, while the receiving modem is still modeled through an impedance matrix (since it behaves as a linear device), an alternative representation is proposed for the transmitting modem, which resorts to the use of two ideal voltage sources in accordance with the substitution theorem. Experimental results prove that the proposed modeling strategy leads to satisfactory predictions of the currents propagating on the PLC system in the frequency interval of interest. Hence, it could be used in combination with high-frequency models of the other components in the network to investigate EMC and the coexistence of the PLC signal with the high-frequency noise generated by power converters.

A New Approach to the Use of Energy from Renewable Sources in Low-Voltage Power Distribution Networks

Currently, in rural networks with a large amount of distributed generation, PV installations are often disconnected due to the excessively high voltage in the network, which often exceeds the limit value, in accordance with the PN-EN 50160 standard. Disconnecting such an installation extends the return on investment costs by preventing the generation of electricity for the owner’s needs and results in the consumption of this energy from the grid. In such a case, the recipient has to bear the costs related to the purchase of this energy. In order to solve the problem of excessively high voltage in a low-voltage distribution network with a large amount of distributed generation, the authors of this article proposed a new approach to the use of electricity from these sources. In order to present the benefits of the proposed solution, a computer simulation was used. In order to carry it out, a mathematical model of a low-voltage power grid with distributed generation was developed using the electric multipole method and Newton’s method, which is discussed in the paper. To determine the advantages of the proposed solution, nine variants of the operation of an exemplary low-voltage power grid over one day were analyzed. The main conclusion based on the analysis of the results is that the proposed approach improves the operation of the power system by maintaining the voltage values within the standard range for the entire tested part of the network. In addition, the proposed approach does not increase the power or electricity when generating electricity from a PV installation. The proposed solution can also serve as a very attractive stimulus for the creation of energy cooperatives.

Evaluation of SVC-Coupled Hybrid DSTATCOM using JLMS Algorithm for Enhancement of Power Quality

Abstract This research study explains the design and performance of a Static VAR Compensator (SVC) coupled Hybrid Distribution Static Compensator (DSTATCOM) for low voltage power distribution system (PDS). A comparative analysisis done between Voltage Source Inverter (VSI)-based DSTATCOM and SVC Hybrid DSTATCOM using Jordan Least Mean Square (JLMS) algorithm to alleviate the shunt-related power quality (PQ) glitches. The specific design is obtained as compared to the existing neural network toolbox algorithm to improve the estimation speed and accuracy. The main objective is to extract the tuned weighted values of fundamental active and reactive power components of distorted load currents for the switching signal generation using an adaptive JLMS algorithm.Several functions of DSTATCOM and hybrid DSTATCOM using this JLMS controller are showcased for harmonics curtailment, power factor (p.f.) improvement, load balancing, voltage regulation, etc. Simulation results on an SVC Hybrid DSTATCOM have shown an acceptable level of performance under unbalanced loading situations. Finally, some comparative results are provided to validate the feasibility and effectiveness of the suggested topology.

Study on the Impact of Rooftop Solar Power Systems on the Low Voltage Distribution Power Grid: A Case Study in Ha Tinh Province, Vietnam

Study on the Impact of Rooftop Solar Power Systems on the Low Voltage Distribution Power Grid: A Case Study in Ha Tinh Province, Vietnam

Reliability Estimation of Low-Voltage Power Distribution Systems

Many accidents always happen in the electricity distribution sector, which requires the use of control strategies in this field. Therefore, this study presented a risk assessment method based on a fuzzy Bayesian network (FBN) and William Fine method in low-voltage power distribution systems to reduce the structural uncertainties of the studies and examined the reliability of these systems to achieve proper performance in emergencies. The first step is to develop a fault tree (FT) and event tree (ET) in bow tie (BT) format. In this study, fuzzy theory and expert judgment were used to qualitatively analyze the root events affecting the system failure and determine the relevant probabilities. Then, deductive and inductive reasoning was done after determining the likelihood of basic events (BEs) and establishing the Bayesian network (BN). Then, the final risk was estimated using William Fine’s method and fuzzy logic. The results of a case study in a low-voltage power distribution system showed that there were 36 BEs and 20 intermediate events (IEs) for system failure, and the reliability of the system was obtained as 0.96654476 and 0.96654476 based on the FT and FBN, respectively. According to the results of BE25 (no installation of the earth) and BE18 (contact of metal objects with the live wire), the most critical events were based on FBN. The results showed that FBN simulation and its combination with static methods such as BT and William Fine provide a suitable method for the accurate identification of distribution systems. Therefore, the approach of the present study can help the decision makers and analysts of the electricity industry to prevent possible failures due to system changes.

Analysis of the failure mode of surge protector under multi-pulse lightning strikes and its mechanism

This paper proposes a special disconnector for surge protector (SPD) with the ability to pass large pulse currents under multiple pulses, which has been verified to solve the problem of SPD fire and combustion under multiple pulses in engineering applications. The safety problem caused by the lightning strike failure of SPD has always been a difficult research point in low-voltage power distribution systems, especially the failure mechanism under multi-pulse lightning strike is still unclear. In this paper, the multi-pulse lightning generator is used to simulate the multi-pulse lightning current to carry out the SPD lightning impulse test. The results show that the SPD will have short-circuit breakdown and fire and combustion under multi-pulse lightning strikes, mainly because the continuous pulses will generate energy superposition, and the built-in disconnector and external disconnector fuses and circuit breakers cannot effectively cooperate with the SPD, and there is a protection blind spot. As a result, the SPD cannot be quickly detached at the moment of a short circuit. Based on the thermal effect of multi-pulse lightning strikes, a multi-pulse SPD special disconnector is designed, which can effectively solve the problem of lightning strike ignition of SPD under multi-pulse lightning strikes, and is of great significance to the lightning protection safety of low-voltage power distribution systems.

저압직류차단기의 소전류 영역 차단특성과 성능향상을 위한 연구

A low voltage direct current(DC) circuit breaker is an electrical protection device that interrupts the abnormal fault currents which result from the over-loads or short-circuits in a low voltage(less than 1,500Vdc) power distribution line. Recently, as interests in renewable energy fields(such as photovoltaic and energy storage systems) have increased, research on DC circuit breakers for system protection is also being actively conducted. However, breaking the fault current in DC system is considerably difficult even small current region since the DC does not have current zero point such as in AC. When a short circuit occurs, a fault current flows between contacts of a DC circuit breaker even though they are separated by the protective control system. Arc voltage between contacts of the circuit breaker should generate as high as possible during breaking phase. High arc voltage could lead the fault current of the circuit to zero so that arc plasma is eliminated. Based on this behavior, arc extinction system of a DC circuit breaker should be designed to effectively increase the arc voltage during current interruption period. In this paper, the characteristics of DC breaking specially in small current region were confirmed through several types of current breaking experiments and result analysis, and a method to improve performance of DC breaking in small current region was presented, and experiments were carried out to verify the validity of the method.

Disconnection-Aware Attack Detection and Isolation With Separation-Based Detector Reconfiguration

This study addresses incident handling during an adverse event for dynamical networked control systems. Incident handling can be divided into five steps: detection, analysis, containment, eradication, and recovery. For networked control systems, the containment step can be conducted through physical disconnection of an attacked subsystem. In accordance with the disconnection, the equipped attack detection unit should be reconfigured to maintain its detection capability. In particular, separating the detection subunit associated with the disconnected subsystem is considered as a specific reconfiguration scheme in this study. This article poses the problem of disconnection-aware attack detection and isolation with the separation-based detector reconfiguration. The objective is to design an attack detection unit that preserves its detection and isolation capability even under any possible disconnection and separation. The difficulty arises from network topology variation caused by disconnection that can possibly lead to stability loss of the distributed observer inside the attack detection unit. A solution is proposed based on an existing controller design technique referred to as retrofit control. Furthermore, an application to low-voltage power distribution networks with distributed generation is exhibited. Numerical examples evidence the practical use of the proposed method through a benchmark distribution network.

Integration of 100-kWp PV with low-voltage distribution power system in composite climate: performance and energy metrics analysis

ABSTRACT In India, PV integration with the low-voltage distribution system is growing rapidly. PV systems require embodied energy for their construction; additionally, they give energy support to the grid and also have an impact on grid parameters including Power Factor (PF), Maximum Demand (MD) and capacitive reactive-power (Q) requirement. Analysing the impact of PV integration on grid supply parameters, including performance and embodied energy-based-energy metrics is the current need. The study is performed by real-time data monitoring on 100-kWp grid-integrated PV in a composite environment. The annual average final yield:(3.76 kWh/kWp/day), system efficiency:(10.89%), performance ratio:(72.15%), energy pay-back time:(6.19 years), electricity production-factor:(4.04) and life cycle conversion efficiency:(12.50%) suggest that the system is energy efficient. The integration of PV with the grid has reduced the average PF and MD to 0.91 (lagging) and 133.63 kVA, respectively, whereas Q has increased to 28.67 kVAR. With a Levelised-cost-of-electricity:(LCOE) of Rs 6.19, the system has a pay-back of 5.29 years.

Planning of Low Voltage Electricity Distribution at Griya Arjuna Kejuden Housing

In a low-voltage power distribution system, there are often disturbances that result in disruption of electricity distribution to customers, resulting in losses for customers and PLN. The problem that often occurs is the occurrence of voltage drops and power losses so that in planning the construction of a low-voltage electric power distribution network, it is necessary to anticipate the occurrence of these problems. This research is expected to be used as a lesson for the creation of a low-voltage electric power distribution network with suitable and environmentally friendly construction and with low investment costs. collected data by visiting the location to conduct a survey and obtain accurate data related to the state of the research location. The stages in planning the Low Voltage Electricity Distribution Network begin with a field survey to obtain the required data. The installed power for each unit is 1.300 VA, so the total installed power is 122,200 VA and the spare power is 5% of the installed power so that the total installed power is 128.310 VA. during peak load times it is estimated that power consumption will only absorb 80% or 97,760VA. The required substation is a Portal Type Pole with a transformator capacity is 160kVA. The total breakdown of the electricity distribution network budget at the Griya Arjuna Kejuden is IDR 382,333,141.

Feeder Load Balancing Using Genetic Algorithms and Artificial Neural Network

Low voltage power distribution system problems such as system planning, energy loss minimization and restoration usually involve proper load balancing or network reconfiguration procedures. To achieve an appreciable level of load phase balance, feeder reconfiguration using appropriate switching control strategy such as: Simulated Annealing, Tabu Search, Particle Swarm Optimization, and heuristic algorithms are viable preferences. However, the systematic solution to load phase balancing can be greatly enhanced optimally through implementation of an appropriate combinatorial optimization procedure such as Genetic Algorithms and Artificial Neural Network. Accordingly, this paper presents a genetic algorithms procedure to enhance the load phase balancing optimization and then train an artificial neural network to automate the reconfiguration of the distribution network loads, thus ensuring an optimal phase balancing in the system. An Intel® 2.0 GHz, 4GB RAM HP255 computer-based MATLAB® 14 was used for the neural network training, testing, and the implementation of the genetic algorithms. The outputs of the algorithms are the switching sequence for a balanced network. The parameters ΔIph (max - min) and Δ(Iph – Imax) which is the maximum difference between the phase currents, which are ideally zero if there are no imbalances in the network, shows considerable improvement in the balancing when compared with other literatures. This work presents the application examples of the proposed methods using real test data.

Concept, Feasibility of Cylindrical Bar Winding for Low Voltage Permanent Magnet Synchronous Motor

In this paper, we present the use of a solid bar winding for a permanent magnet synchronous motor dedicated to the electric drive of a full electric boat. For the winding, we chose to use cylindrical bars for the electric vehicle motorizations of a power lower than 10 kW. The choice of a 60 VDC low-voltage power distribution requires resorting to a solid bar winding with one bar per slot (single turn). Hence, the solid conductors dissipate additional copper losses (higher AC resistance). An analysis of these additional copper losses was carried out to accurately assess the effective AC resistance of the winding and, hence, the efficiency of the electric motor. A prototype for a POD propulsion was designed, built and tested. The characteristics of its electric motor were presented. The feasibility this type of cylindrical bar winding has been proven. A study on the optimization of the slot has demonstrated the performance of this type of winding.

Transactive Coordination of Electric Vehicles With Voltage Control in Distribution Networks

This paper proposes a novel sensitivity-based transactive energy (TE) framework for real-time coordination of electric vehicles (EVs) with voltage control in low-voltage (LV) power distribution network (PDN). The proposed framework employs a combination of economic and control mechanisms that enables EVs to participate in the real-time local energy market (LEM) and mitigates the voltage issues in the PDN through EVs’ charge/discharge scheduling. Prioritizing EV owners’ preferences and concerns, the proposed method can achieve customers’ satisfaction through EV owners’ active participation in the LEM, in which they can bid to the retail market and decide on energy transactions. A new sensitivity-based voltage control scheme is presented considering an incentivized dynamic power curtailment of EV charge in the node of the PDN where a voltage violation is investigated. The proposed model is implemented in the IEEE 55-node LV European test feeder system to investigate its effectiveness in different scenarios and at different EV penetration levels. Simulation results demonstrate the effectiveness of the proposed system in terms of achieving higher EV owners’ satisfaction, and robustness in voltage control.