1,180 research outputs found
Current Status and Future Trends of Power Quality Analysis
In this article, a systematic literature review of 153 articles on power quality analysis in
PV systems published in the last 20 years is presented. This provides readers with an overview
on PQ trends in several fields related to instrumental techniques that are being used in the smart
grid to visualize the quality of the energy, establishing a solid literature base from which to start
future research. A preliminary appreciation allows us to intuit that higher-order statistics are not
implemented in measurement equipment and that traditional instrumentation is still used for the
performance of measurement campaigns, not yielding the expected results since the information
processed does not come from an electrical network from 20 years ago. Instead, current networks
contain numerous coupled load effects; thus, new disturbances are not simple; they are usually
complex events, the sum of several types of disturbances. Likewise, depending on the type of
installation, the objective of the PQ analysis changes, either by detecting certain events or simply
focusing on seeing the state of the network
Site Characterization Index for Continuous Power Quality Monitoring Based on Higher-order Statistics
The high penetration of distributed generation (DG) has set up a challenge for energy management and consequently for the monitoring and assessment of power quality (PQ). Besides, there are new types of disturbances owing to the uncontrolled connections of non-linear loads. The stochastic behaviour triggers the need for new holistic indicators which also deal with big data of PQ in terms of compression and scalability so as to extract the useful information regarding different network states and the prevailing PQ disturbances for future risk assessment and energy management systems. Permanent and continuous monitoring would guarantee the report to claim for damages and to assess the risk of PQ distortions. In this context, we propose a measurement method that postulates the use of two-dimensional (2D) diagrams based on higher-order statistics (HOSs) and a previous voltage quality index that assesses the voltage supply waveform in a continous monitoring campaign. Being suitable for both PQ and reliability applications, the results conclude that the inclusion of HOS measurements in the industrial metrological reports helps characterize the deviations of the voltage supply waveform, extracting the individual customers' pattern fingerprint, and compressing the data from both time and spatial aspects. The method allows a continuous and robust performance needed in the SG framework. Consequently, the method can be used by an average consumer as a probabilistic method to assess the risk of PQ deviations in site characterization.This work was supported by the Spanish Ministry of Science and Innovation (Statal Agency for Research), and the EU (AEI/FEDER/UE) via project PID2019-108953RB-C21 Strategies for Aggregated Generation of Photovoltaic Plants: Energy and Meteorological Operational Data (SAGPVEMOD), and the precedent TEC2016-77632-C3-3-R
Intelligent Methods for Characterization of Electrical Power Quality Signals using Higher Order Statistical Features
This paper considers a few important techniques classification for to identify several power quality disturbances. For this purpose, a process
based in HOS has been realized to extract features that help in classification. In this stage the geometrical pattern established via higher-order
statistical measurements is obtained, and this pattern is function of the amplitudes and frequencies of the power quality disturbances associated to the
50-Hz power-line. Once the features are managed will be segmented to form training and test sets and them will be applied in the statistical methods
used to perform automatic classification of PQ disturbances. The best technique of those compared is selected according to correlation and mistake
rates
Power Quality
Electrical power is becoming one of the most dominant factors in our society. Power
generation, transmission, distribution and usage are undergoing signifi cant changes
that will aff ect the electrical quality and performance needs of our 21st century industry.
One major aspect of electrical power is its quality and stability – or so called Power
Quality.
The view on Power Quality did change over the past few years. It seems that Power
Quality is becoming a more important term in the academic world dealing with electrical
power, and it is becoming more visible in all areas of commerce and industry, because
of the ever increasing industry automation using sensitive electrical equipment
on one hand and due to the dramatic change of our global electrical infrastructure on
the other.
For the past century, grid stability was maintained with a limited amount of major
generators that have a large amount of rotational inertia. And the rate of change of
phase angle is slow. Unfortunately, this does not work anymore with renewable energy
sources adding their share to the grid like wind turbines or PV modules. Although the
basic idea to use renewable energies is great and will be our path into the next century,
it comes with a curse for the power grid as power fl ow stability will suff er.
It is not only the source side that is about to change. We have also seen signifi cant
changes on the load side as well. Industry is using machines and electrical products
such as AC drives or PLCs that are sensitive to the slightest change of power quality,
and we at home use more and more electrical products with switching power supplies
or starting to plug in our electric cars to charge batt eries. In addition, many of us
have begun installing our own distributed generation systems on our rooft ops using
the latest solar panels. So we did look for a way to address this severe impact on our
distribution network. To match supply and demand, we are about to create a new, intelligent
and self-healing electric power infrastructure. The Smart Grid. The basic idea
is to maintain the necessary balance between generators and loads on a grid. In other
words, to make sure we have a good grid balance at all times. But the key question that
you should ask yourself is: Does it also improve Power Quality? Probably not!
Further on, the way how Power Quality is measured is going to be changed. Traditionally,
each country had its own Power Quality standards and defi ned its own power
quality instrument requirements. But more and more international harmonization efforts
can be seen. Such as IEC 61000-4-30, which is an excellent standard that ensures
that all compliant power quality instruments, regardless of manufacturer, will produce of measurement instruments so that they can also be used in volume applications and
even directly embedded into sensitive loads. But work still has to be done. We still use
Power Quality standards that have been writt en decades ago and don’t match today’s
technology any more, such as fl icker standards that use parameters that have been defi
ned by the behavior of 60-watt incandescent light bulbs, which are becoming extinct.
Almost all experts are in agreement - although we will see an improvement in metering
and control of the power fl ow, Power Quality will suff er. This book will give an
overview of how power quality might impact our lives today and tomorrow, introduce
new ways to monitor power quality and inform us about interesting possibilities to
mitigate power quality problems.
Regardless of any enhancements of the power grid, “Power Quality is just compatibility”
like my good old friend and teacher Alex McEachern used to say.
Power Quality will always remain an economic compromise between supply and load.
The power available on the grid must be suffi ciently clean for the loads to operate correctly,
and the loads must be suffi ciently strong to tolerate normal disturbances on the
grid
Comprehensive Review on Detection and Classification of Power Quality Disturbances in Utility Grid With Renewable Energy Penetration
The global concern with power quality is increasing due to the penetration of renewable energy (RE) sources to cater the energy demands and meet de-carbonization targets. Power quality (PQ) disturbances are found to be more predominant with RE penetration due to the variable outputs and interfacing converters. There is a need to recognize and mitigate PQ disturbances to supply clean power to the consumer. This article presents a critical review of techniques used for detection and classification PQ disturbances in the utility grid with renewable energy penetration. The broad perspective of this review paper is to provide various concepts utilized for extraction of the features to detect and classify the PQ disturbances even in the noisy environment. More than 220 research publications have been critically reviewed, classified and listed for quick reference of the engineers, scientists and academicians working in the power quality area
Power quality events detection using fourth-order spectra
This paper introduces the use of a fourth-order
frequency-domain statistical estimator, the spectral kurtosis
(SK), in the field of power-quality analysis. The research has
been organized in the frame of a research national project
and points towards the implementation of these techniques
into an automatic platform to perform PQ analysis in power
plants and power inverters. Higher-order statistics in the
frequency domain manage to distinguish 3 types of electrical
anomalies (sags, swells and transients), with an accuracy of
83%
Advances in power quality analysis techniques for electrical machines and drives: a review
The electric machines are the elements most used at an industry level, and they represent the major power consumption of the productive processes. Particularly speaking, among all electric machines, the motors and their drives play a key role since they literally allow the motion interchange in the industrial processes; it could be said that they are the medullar column for moving the rest of the mechanical parts. Hence, their proper operation must be guaranteed in order to raise, as much as possible, their efficiency, and, as consequence, bring out the economic benefits. This review presents a general overview of the reported works that address the efficiency topic in motors and drives and in the power quality of the electric grid. This study speaks about the relationship existing between the motors and drives that induces electric disturbances into the grid, affecting its power quality, and also how these power disturbances present in the electrical network adversely affect, in turn, the motors and drives. In addition, the reported techniques that tackle the detection, classification, and mitigations of power quality disturbances are discussed. Additionally, several works are reviewed in order to present the panorama that show the evolution and advances in the techniques and tendencies in both senses: motors and drives affecting the power source quality and the power quality disturbances affecting the efficiency of motors and drives. A discussion of trends in techniques and future work about power quality analysis from the motors and drives efficiency viewpoint is provided. Finally, some prompts are made about alternative methods that could help in overcome the gaps until now detected in the reported approaches referring to the detection, classification and mitigation of power disturbances with views toward the improvement of the efficiency of motors and drives.Peer ReviewedPostprint (published version
An Embedded System in Smart Inverters for Power Quality and Safety Functionality
The electricity sector is undergoing an evolution that demands the development of a
network model with a high level of intelligence, known as a Smart Grid. One of the factors accelerating
these changes is the development and implementation of renewable energy. In particular, increased
photovoltaic generation can affect the network’s stability. One line of action is to provide inverters
with a management capacity that enables them to act upon the grid in order to compensate for these
problems. This paper describes the design and development of a prototype embedded system able to
integrate with a photovoltaic inverter and provide it with multifunctional ability in order to analyze
power quality and operate with protection. The most important subsystems of this prototype are
described, indicating their operating fundamentals. This prototype has been tested with class A
protocols according to IEC 61000-4-30 and IEC 62586-2. Tests have also been carried out to validate
the response time in generating orders and alarm signals for protections. The highlights of these
experimental results are discussed. Some descriptive aspects of the integration of the prototype in an
experimental smart inverter are also commented upon
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