Automatic Identification of Different Types of Consumer Configurations by Using Harmonic Current Measurements

Power quality (PQ) is an increasing concern in the distribution networks of modern industrialized countries. The PQ monitoring activities of distribution system operators (DSO), and consequently the amount of PQ measurement data, continuously increase, and consequently new and automated tools are required for efficient PQ analysis. Time characteristics of PQ parameters (e.g., harmonics) usually show characteristic daily and weekly cycles, mainly caused by the usage behaviour of electric devices. In this paper, methods are proposed for the classification of harmonic emission profiles for typical consumer configurations in public low voltage (LV) networks using a binary decision tree in combination with support vector machines. The performance of the classification was evaluated based on 40 different measurement sites in German public LV grids. This method can support network operators in the identification of consumer configurations and the early detection of fundamental changes in harmonic emission behaviour. This enables, for example, assistance in resolving customer complaints or supporting network planning by managing PQ levels using typical harmonic emission profiles.

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Machine Learning and GIS Approach for Electrical Load Assessment to Increase Distribution Networks Resilience

Energies ◽

10.3390/en14144133 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4133

Author(s):

Alessandro Bosisio ◽

Matteo Moncecchi ◽

Andrea Morotti ◽

Marco Merlo

Keyword(s):

Machine Learning ◽

Distribution System ◽

Low Voltage ◽

Regression Tree ◽

Distribution Networks ◽

Machine Learning Algorithms ◽

Extreme Weather Events ◽

Medium Voltage ◽

Weather Events ◽

Building Area

Currently, distribution system operators (DSOs) are asked to operate distribution grids, managing the rise of the distributed generators (DGs), the rise of the load correlated to heat pump and e-mobility, etc. Nevertheless, they are asked to minimize investments in new sensors and telecommunication links and, consequently, several nodes of the grid are still not monitored and tele-controlled. At the same time, DSOs are asked to improve the network’s resilience, looking for a reduction in the frequency and impact of power outages caused by extreme weather events. The paper presents a machine learning GIS-based approach to estimate a secondary substation’s load profiles, even in those cases where monitoring sensors are not deployed. For this purpose, a large amount of data from different sources has been collected and integrated to describe secondary substation load profiles adequately. Based on real measurements of some secondary substations (medium-voltage to low-voltage interface) given by Unareti, the DSO of Milan, and georeferenced data gathered from open-source databases, unknown secondary substations load profiles are estimated. Three types of machine learning algorithms, regression tree, boosting, and random forest, as well as geographic information system (GIS) information, such as secondary substation locations, building area, types of occupants, etc., are considered to find the most effective approach.

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Robust and Fast State Estimation for Poorly-Observable Low Voltage Distribution Networks Based on the Kalman Filter Algorithm

Energies ◽

10.3390/en12234457 ◽

2019 ◽

Vol 12 (23) ◽

pp. 4457 ◽

Cited By ~ 1

Author(s):

Antončič ◽

Papič ◽

Blažič

Keyword(s):

Kalman Filter ◽

State Estimation ◽

Low Voltage ◽

Least Squares Method ◽

Weighted Least Squares ◽

Measurement Data ◽

Estimation Algorithm ◽

Distribution Networks ◽

Voltage Distribution ◽

State Estimator

This paper presents a novel approach for the state estimation of poorly-observable low voltage distribution networks, characterized by intermittent and erroneous measurements. The developed state estimation algorithm is based on the Extended Kalman filter, where we have modified the execution of the filtering process. Namely, we have fixed the Kalman gain and Jacobian matrices to constant matrices; their values change only after a larger disturbance in the network. This allows for a fast and robust estimation of the network state. The performance of the proposed state-estimation algorithm is validated by means of simulations of an actual low-voltage network with actual field measurement data. Two different cases are presented. The results of the developed state estimator are compared to a classical estimator based on the weighted least squares method. The comparison shows that the developed state estimator outperforms the classical one in terms of calculation speed and, in case of spurious measurements errors, also in terms of accuracy.

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Water Loss Management in Small Municipalities: The Situation in Tyrol

Water ◽

10.3390/w12123446 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3446

Author(s):

Martin Oberascher ◽

Michael Möderl ◽

Robert Sitzenfrei

Keyword(s):

Low Income ◽

Water Loss ◽

Water Distribution ◽

Management Strategies ◽

Measurement Data ◽

Distribution Networks ◽

Support Network ◽

Federal State ◽

Water Losses ◽

Water Loss Management

Water losses in water distribution networks (WDNs) are unavoidable. Water losses are evaluated based on performance indicators (PIs) and used for future recommendations for network operators to take measures against water losses. However, these evaluations primarily focus on large and medium sized WDN and do not deal with the challenges of small WDNs (e.g., technical, and financial limitations, missing data). Therefore, an appropriate water loss management is a major challenge for operators in the federal state of Tyrol (Austria) due to the high number of small WDNs, e.g., low income in combination with long network lengths. In this regard, this work specifies and discusses state funding in Austria to support network operators to reduce water losses. To assess the impacts on management strategies, 40 WDNs, supplying 200 to 16,000 inhabitants, are investigated in detail. As the comparison of different PIs shows, a volume related PI (e.g., water loss volume divided by total water demand) is recommend as the decision criterion for local authorities due to minimal efforts and its easy calculation. Moreover, public funding helps to significantly reduce water losses in individual systems, but countermeasures should be different for small and larger WDNs. For example, leakage detection campaigns and rehabilitation planning based on pipe age should be established in future for larger WDNs in Tyrol. In contrast, an online flow metering system to monitor system inflows is suggested for small WDNs. Based on measurement data, leakages and burst can be detected and repaired swiftly.

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Smart Meter Traffic in a Real LV Distribution Network

Energies ◽

10.3390/en11051156 ◽

2018 ◽

Vol 11 (5) ◽

pp. 1156 ◽

Cited By ~ 5

Author(s):

Nikoleta Andreadou ◽

Evangelos Kotsakis ◽

Marcelo Masera

Keyword(s):

Distribution System ◽

Low Voltage ◽

Distribution Network ◽

Distribution Networks ◽

Smart Meter ◽

Advanced Metering Infrastructure ◽

Distribution Grid ◽

Message Size ◽

Real Distribution ◽

Advanced Metering

The modernization of the distribution grid requires a huge amount of data to be transmitted and handled by the network. The deployment of Advanced Metering Infrastructure systems results in an increased traffic generated by smart meters. In this work, we examine the smart meter traffic that needs to be accommodated by a real distribution system. Parameters such as the message size and the message transmission frequency are examined and their effect on traffic is showed. Limitations of the system are presented, such as the buffer capacity needs and the maximum message size that can be communicated. For this scope, we have used the parameters of a real distribution network, based on a survey at which the European Distribution System Operators (DSOs) have participated. For the smart meter traffic, we have used two popular specifications, namely the G3-PLC–“G3 Power Line communication” and PRIME–acronym for “PoweRline Intelligent Metering Evolution”, to simulate the characteristics of a system that is widely used in practice. The results can be an insight for further development of the Information and Communication Technology (ICT) systems that control and monitor the Low Voltage (LV) distribution grid. The paper presents an analysis towards identifying the needs of distribution networks with respect to telecommunication data as well as the main parameters that can affect the Inverse Fast Fourier Transform (IFFT) system performance. Identifying such parameters is consequently beneficial to designing more efficient ICT systems for Advanced Metering Infrastructure.

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Investigation on Using Low Voltage Automatic Regulation to Minimize the Impacts of Charging Plug-in Electric Vehicles in Distribution Systems

Renewable Energy and Power Quality Journal ◽

10.24084/repqj19.222 ◽

2021 ◽

Vol 19 ◽

pp. 85-90

Author(s):

Priscila Costa Nascimento ◽

◽

Michel Girotto de Oliveira ◽

José Carlos M. Vieira

Keyword(s):

Steady State ◽

Electric Vehicles ◽

Distribution System ◽

Distribution Systems ◽

Low Voltage ◽

Electric Energy ◽

Distribution Networks ◽

Voltage Regulation ◽

Automatic Regulation ◽

Electric Energy Storage

The growth of micro and mini distributed generation and, more recently, the use of electric energy storage systems and the incentives for electric mobility are important examples of the transformations that distribution networks have been going through. In this context, this paper firstly presents the impacts of uncoordinated plug-in electric vehicles (PEVs) charging in a real Brazilian distribution system. Four scenarios were elaborated with different PEVs penetration levels and the results show increased voltage unbalance, system losses, and violations of the steady-state voltage limits, even in the presence of an automatic voltage regulator installed in the medium voltage network. Then, as the main contribution, the potential usage of automatic voltage regulation at the low voltage network was investigated to minimize the negative impacts of uncontrolled PEV charging on distribution system steady-state operation. It is important to highlight that this is not a common practice of utilities in Brazil. The obtained results showed that regulating the voltage at the low voltage side could be an effective solution to keep the voltages within statutory limits.

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Predictive Voltage Control: Empowering Domestic Customers With a Key Role in the Active Management of LV Networks

Applied Sciences ◽

10.3390/app10072635 ◽

2020 ◽

Vol 10 (7) ◽

pp. 2635

Author(s):

Micael Simões ◽

André G. Madureira

Keyword(s):

Distribution System ◽

Smart Grids ◽

Low Voltage ◽

Voltage Control ◽

Distribution Networks ◽

Active Management ◽

Storage Devices ◽

Home Energy Management ◽

System Operator ◽

Home Energy Management System

In order to avoid voltage problems derived from the connection of large amounts of renewable-based generation to the electrical distribution system, new advanced tools need to be developed that are able to exploit the presence of Distributed Energy Resources (DER). This paper describes the approach proposed for a predictive voltage control algorithm to be used in Low Voltage (LV) distribution networks in order to make use of available flexibilities from domestic consumers via their Home Energy Management System (HEMS) and more traditional resources from the Distribution System Operator (DSO), such as transformers with On-Load Tap Changer (OLTC) and storage devices. The proposed algorithm—the Low Voltage Control (LVC)—is detailed in this paper. The algorithm was tested through simulation using a real Portuguese LV network and real consumption and generation data, in order to evaluate its performance in preparation for a field-trial validation in a Portuguese smart grids pilot.

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On the Conflict between LVRT and Line Protection in LV Distribution Systems with PVs: A Current-Limitation-Based Solution

Energies ◽

10.3390/en12152909 ◽

2019 ◽

Vol 12 (15) ◽

pp. 2909 ◽

Cited By ~ 1

Author(s):

Aristotelis Tsimtsios ◽

Dionisis Voglitsis ◽

Ioannis Perpinias ◽

Christos Korkas ◽

Nick Papanikolaou

Keyword(s):

Distribution System ◽

Distribution Systems ◽

Low Voltage ◽

Energy Resource ◽

Distribution Networks ◽

Voltage Distribution ◽

Current Limitation ◽

Protection Scheme ◽

Low Voltage Ride Through ◽

Photovoltaic Generators

The upcoming adoption of low-voltage-ride-through requirements in low-voltage distribution systems is expected to raise significant challenges in the operation of grid-tied inverters. Typically, these inverters interconnect photovoltaic units, which are the predominant distributed energy resource in low-voltage distribution networks, under an umbrella of standards and protection schemes. As such, a challenging issue that should be considered in low-voltage distribution network applications, regards the coordination between the line protection scheme (typically consisting of a non-settable fuse) and the low-voltage-ride-through operation of photovoltaic generators. During a fault, the fuse protecting a low-voltage feeder may melt, letting the generator to continue its ride-through operation. Considering that the efficacy/speed of the anti-islanding detection is affected by ride-through requirements, this situation can lead to protracted energization of the isolated feeder after fuse melting (unintentional islanding). To address this issue, this paper proposes a fault-current-limitation based solution, which does not require any modification in the existing protection scheme. The operation principles, design, and implementation of this solution are presented, while, its effectiveness is supported by extensive simulations in a test-case low-voltage distribution system. A discussion on the presented results concludes the paper.

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Energy Loss Minimization by Optimal Siting and Sizing of DG with Network Reconfiguration in Distribution Networks

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.j9792.0881019 ◽

2019 ◽

Vol 8 (10) ◽

pp. 3621-3625

Keyword(s):

Energy Loss ◽

Distribution System ◽

Power Loss ◽

Reactive Power ◽

Low Voltage ◽

Distribution Networks ◽

Network Reconfiguration ◽

Voltage Profile ◽

Loss Minimization ◽

Power Loss Reduction

The main aim of the distribution system is delivery the power to the consumers. Because of, aging of electrical infrastructure, old control mechanism, increased power demand causing exploitation of the present electrical networks leads to low voltage profile, more active and reactive power loss with various power quality related issues causing poor network operation. In this method maximization of voltage profile with energy loss minimization is carried using network reconfiguration along with optimal siting of the distributed generation (DG). The proposed methodology is carried out on five bus system. The obtained results are impressive interms of voltage stability and power loss reduction.

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Demonstration of a microgrid manager in a distribution grid with high PV penetration and Storage: La Graciosa case study

E3S Web of Conferences ◽

10.1051/e3sconf/20186100012 ◽

2018 ◽

Vol 61 ◽

pp. 00012

Author(s):

Guillermo Domínguez-López ◽

Pol Paradell-Solà ◽

José Luis Domínguez-García ◽

Jacob Rodríguez-Rivero ◽

Jorge Sánchez-Cifuentes

Keyword(s):

Power Systems ◽

Distribution System ◽

New Technologies ◽

Low Voltage ◽

Storage System ◽

Distribution Networks ◽

Energy Storage System ◽

Monitoring And Control ◽

Distribution Grid ◽

Grid Operation

Future power systems with high penetration of distributed energy resources (DER) and information and communication technology (ICT) will allow increasing the controllability and observability of the grid. However, new challenges for low voltage distribution networks has arisen where the increasing DER is mainly photovoltaic (PV) installed on the roofs of buildings. This type of generation is variable and generates disturbances in the network. Islands are ideal to experience and install new technologies since are weak grids and the penetration of PV will lead to bidirectional power flows at distribution level, thus a smart control will be required. This article aims to present and innovative tool for the distribution system operators (DSOs) to monitor and manage grid operation. In near future, both DER and client’s flexibility will increase. New monitoring and control tools for DSOs are essential. Furthermore, the grid operation optimization is needed to accommodate the expected DER installations and the active participation of consumers’ flexibility services in markets ensuring system efficiency. This tool is tested on “La Graciosa” grid, one of the Canary Islands, to show its benefit. The grid studied includes a hybrid energy storage system (HESS), PV generators, controllable/uncontrollable loads and equipment to monitor power flows.

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Influence of FACTS Device Implementation on Performance of Distribution Network with Integrated Renewable Energy Sources

Energies ◽

10.3390/en13205516 ◽

2020 ◽

Vol 13 (20) ◽

pp. 5516

Author(s):

Filip Relić ◽

Predrag Marić ◽

Hrvoje Glavaš ◽

Ivica Petrović

Keyword(s):

Renewable Energy ◽

Distribution System ◽

Low Voltage ◽

Flow Direction ◽

Renewable Energy Sources ◽

Distribution Network ◽

Distribution Networks ◽

Energy Sources ◽

Voltage Profile ◽

Facts Devices

In the modern power system, Flexible Alternating Current Transmission System (FACTS) devices are widely used. An increased share of the distributed generation (DG) and the development of microgrids change the power flows in the existing distribution networks as well as a conventional power flow direction from the transmission to the distribution network level which may affect the overall stability aspects. The paper shows the FACTS devices’ implementation influence on the performance of the distribution network with integrated renewable energy sources (RES) observing the aspects of the oscillatory stability and the low-voltage motor starting. The FACTS devices, in particular the static var compensators (SVC), have been allocated according to a novel algorithm proposed in the paper. The algorithm uses an iterative process to determine an optimal location for implementation and rating power of SVC considering active power losses minimization, improvement of the voltage profile and maximizing return of investment (ROI) of FACTS devices. Novel constraints—transformer station construction constraint, SVC industrial nominal power value constraint and the constraint of distribution system operator (DSO) economic willingness to investment in the distribution network development are considered in the proposed algorithm. The analysis has been performed on 20 kV rural distribution network model in DIgSILENT PowerFactory software.

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