Introduction to Low Voltage Networks

Given the increasing penetration of distributed energy resources (DER) in low-voltage networks, peer-to-peer (P2P) energy trading has been proposed to facilitate DER integration into power systems.

The studies allowed obtaining data on the daily consumption of electricity in individual outgoing lines, information on the characteristics of consumers, digital information (database) on indicators of the quality of electricity in low-voltage networks.

The presently observed rapid increase in photovoltaic (PV) micro-installation connections to low-voltage networks, resulting from numerous financial support programmes, European Union (EU) energy policy and growing social awareness of environmental and economic issues, raise the question if PV inverters widely available in EU market fulfil the numerous technical requirements specified in European and Polish regulations.

The experimental tests are carried out on low-voltage networks 380/220 V.

This paper presents a method to identify radially operated low-voltage networks which can be applied with limited number of smart meters.

) in low-voltage networks.

Non-negligible amounts of Distributed Generating Units (DGUs) are already connected to power systems, predominantly to medium- and low-voltage networks.

This article presents a comparison of measurement methods for current and voltage distortions in low-voltage networks in the frequency range from 2 to 150 kHz (supraharmonics).

These algorithms – described in standards and national regulations – were tested in a typical inverter used in public low-voltage networks and implemented in the created simulation model of the relay.

The increasing penetration level of photovoltaic (PV) systems in low-voltage networks causes voltage regulation issues.

The developed methods are applied to an exemplary case study with Norwegian low-voltage networks.

This provides stable operation of the system and achieves higher effectiveness due to the lower X/R ratio at the point of common coupling in low-voltage networks.

A comprehensive installation of measuring instruments in the medium- and low-voltage networks has proved economically unviable.

French regulation allows consumers in low-voltage networks to form collectives to produce, share, and consume local energy under the collective self-consumption framework.

The first part of the article presents an analysis of the distribution of values for the introduced energy density and energy losses in the lines of medium- and low-voltage networks and in transformers supplying the low-voltage network.

Additional results for 128 low-voltage networks, examine the quality of the solutions obtained with the proposed relaxation.

As far as a large number of low-voltage networks, and the associated large sum of cost savings are concerned, the proposed planning framework is practical to be applied and expected to be served as a new guideline for future implementation in Thailand.

The performance of the proposed control algorithm is validated against the optimal power flow (OPF) using data from real low-voltage networks.

The conclusions that can be extracted from this study will allow the researchers to determine whether or not a given configuration is applicable for a specific application since conventional smart metering infrastructure does not provide the necessary bandwidth to be used in some cases like for instance real time flexibility management in low-voltage networks.

Taking into account the growth of distributed generation systems in low-voltage networks, it is important to fully exploit the energy resources and their embedded power converter.

The chapter then considers the impact of uncoordinated DER control on the operation of low-voltage networks, followed by a discussion of active management of DERs, including peer-to-peer trading with a distribution system operator permission structure and distributed optimal power flow.

In this paper, we consider the main reasons of power quality deterioration in low-voltage networks.

Distributed PV systems at low-voltage networks lead to power quality issues, while large-scale PV farms have impacts on transmission network and generation assets.

Then, the Cigre benchmark medium- and low-voltage networks are used to substantiate the findings.

The increasing uptake of distributed energy resources in distribution systems and the rapid advance of technology have established new scenarios in the operation of low-voltage networks.

This work tackles the exact approach to the voltage optimization problem of active low-voltage networks when transformers with on-load tap changers are available.

The development of distributed generation, and especially the installation of PV sources in low-voltage networks in highly urbanized areas, leads to the emergence of new challenges related to the maintenance of the required electrical energy parameters.

In the Danish power system, PV plants are mostly integrated in the medium- and low-voltage networks which are usually operating under unbalanced conditions.

Based on the physical equivalence dynamic reduction technique, this method improves the standard equivalent structures of low-voltage networks, takes into account the negative sequence and zero sequence currents under asymmetric short-circuit faults, and adopts a practical engineering method of parameter aggregation of equivalent generators and selection of controller models.

This study presents a novel approach for ensuring the power quality and reliability of supply required for low-voltage networks with distributed energy sources.

A method is proposed in this paper to determine the harmonic impedances in low-voltage networks in a stochastic way.

For this reason, several studies approach the modeling of these lighting loads to analyze their impact on the harmonic distortion in low-voltage networks.

This paper investigates use of such models for protection studies in low-voltage networks.

This paper explores the particular properties of developing local energy trading schemes in low-voltage networks by comparing two different approaches, which obviate many of the challenges of local energy markets (LEMs).

A high share of distributed photovoltaic (PV) generation in low-voltage networks may lead to over-voltage, and line/transformer overloading.