Power Quality of Electrical Power Systems

Power Quality of Electrical Power Systems

Feras Youssef Mahfoud (Universitatea Politehnica Bucureşti, Romania), Basarab Dan Guzun (Universitatea Politehnica Bucureşti, Romania), George Cristian Lazaroiu (University Politehnica of Bucharest, Romania) and H. H. Alhelou (Tishreen University, Syria)
Copyright: © 2019 |Pages: 24
DOI: 10.4018/978-1-5225-8030-0.ch011

Abstract

Power quality problems can cause processes and equipment to malfunction or shut down. And the consequences can range from excessive energy costs to complete work stoppage. Obviously, power quality is critical. There are many ways in which a power feed can be poor quality, and so no single figure can completely quantify the quality of a power feed. In this chapter, the authors present all definitions, classifications, and problems related to power quality. Finally, they do a comparison between the practical measurements and standards related to power quality.
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Introduction

Electrical energy is one of the most important of raw materials for the time being used in all areas of life Industrial, commercial, agricultural and domestic. Electrical energy is a product, but a product unusual, this is due to two reasons:

  • 1.

    Cannot be stored in quantities.

  • 2.

    Cannot be subject to quality safety tests.

Therefore, the electrical energy is transferred from generation place to consumption directly without any tests or examinations, so that electricity must be able to fulfill their function properly without any problems and this is what is called the power quality.

An electrical power system is expected to deliver undistorted sinusoidal rated voltage and current continuously at rated frequency to the end users. Electric power quality has captured increasing attention in power engineering in recent years.

Background of Power Quality

Power Quality is defined as “any power problem manifested in voltage, current, and/or frequency deviations that results in the failure and/or mal-operation of end user’s equipment. PQ is simply the interaction of electric power with electrical equipment.

Electromagnetic Compatibility (“EMC”) and is defined as: “the ability of an equipment or system to function satisfactorily in its electromagnetic environment without introducing excessive electromagnetic disturbances to anything in that environment.” (Ferracci, 2001).

Sometimes, Power quality is a term used to discuss events on electric power grids that can damage or disrupt sensitive electronic devices. There are many ways in which a power feed can be poor quality, and so no single figure can completely quantify the quality of a power feed.

Power quality problems can cause processes and equipment to malfunction or shut down. And the consequences can range from excessive energy costs to complete work stoppage. Obviously, power quality is critical.

Poor power quality can result in lost productivity, lost and corrupt data, damaged equipment and poor power efficiency. When added up, U.S. companies waste an estimated $26 billion on electrical power-related issues each year.

Power quality problems make their effects felt in three general areas: downtime, equipment problems, and energy costs.

The Electric Power Research Institute (EPRI) conducted a five-year (1990-1995) monitoring program for distribution power quality (DPQ-I) among 24 utilities throughout the United States of America. Another program DPQ-II was conducted in 2001-2002. These study results that voltage sags (dips) and swells, transient over-voltages (due to capacitor switching), harmonics and grounding Power Quality related problems are the most common PQ complaints among the American customer as presented in Figure 1 (Eberhard, 2011 & Alhelou et al 2018).

Figure 1.

PQ problems experienced by the American customers

978-1-5225-8030-0.ch011.f01

The best measure of power quality is the ability of electrical equipment to operate in a satisfactory manner, given proper care and maintenance and without adversely affecting the operation of other electrical equipment connected to the system (Ferracci et al 2001 & Makdisi et al 2018).

Key Terms in this Chapter

Frequency: In statistics the frequency (or absolute frequency) of an event is the number of times the event occurred in an experiment or study. These frequencies are often graphically represented in histograms.

Good Power Quality: Good power quality can be defined as a steady supply voltage that stays within the prescribed range, steady AC frequency close to the rated value, and smooth voltage curve waveform (resembles a sine wave).

Power Quality Compression Algorithm: A power quality compression algorithm is an algorithm used in the analysis of power quality.

Voltage Quality: Voltage quality is used to refer to all disturbances in the supply of electricity, excluding interruptions that are covered.

Power Quality: Electric power quality, or simply power quality, involves voltage, frequency, and waveform.

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