In a modern technological society, power system is a form infrastructure to provide electrical energy from one location to the other for the optimize utilization of consumers. Essentially, power systems are the physical devices to transport, distribute, and transform energy system to diverse needs for the technological development. An essential feature of power systems is its ability to convert energy from a raw form and transmits the energy system from power sources and delivers to consumers for various uses. For the optimum distribution of energy, power systems contain network systems based upon voltage that consists of 275kV, 132kV, 66kV, etc. Through the distribution of power system, modern technological society has been able to generate electricity for diverse needs. (South Australian Government, 2001).
Recently, there is growing increase in the number of consumers who demand for more quality power systems in order to maximise their total utility. The major reason is that consumers have become increasingly aware of their right to demand for reliable, low cost and high quality energy systems for the industrial and domestic uses. To satisfy customers demand, energy providers have employed several devices in providing power quality to customers. For example, energy providers are shifting away from large power stations to small units in order generates energy with a lower voltage. Typically, customers satisfactions is an integral part of organisational growth, and many energy providers have realised that provision of power quality is very essential to retain existing customers, and attract new customers.
To enhance greater understanding of power quality, there is need to illustrate the term power quality.
Overview of power quality
The term power quality is the combination of quality from voltage and quality supplied from current. To achieve power quality, current quality should complement with voltage quality where quality of power supplied should involve ideal non-technical interaction from network of power to customers. To provide essential power quality to consumers, the energy providers need to supply accepted electrical energy to consumers without power interruption.
Typically, there are different phenomena of power quality. These phenomena are categorised as follows
1. Power quality events
2. Power quality variations
Although, there are no noticeable difference between the two phenomena. The term variation occurs when there are continuous disturbances in the energy system while event occurs when there are infrequent disturbances.
Under power quality event, there are various power disturbances that occur.
Voltage Sag or Voltage dip This occurs when there is reduction of AC voltage from half to little duration. This consequence can cause motor to start and switching an electronic loads.
Voltage swell This occurs when there is increase in power frequency of AC voltage from half to little duration.
Voltage surge The power quality disturbances occur when there is a sharp increase in current or voltage.
Voltage unbalance This occurs when there is imbalance between the percentage ratio of negative sequence and ratio of positive component.
Transient The disturbances occur when there is unanticipated change in voltage which happens by unprecedented occurrence.
Voltage interruption This is a kind of power quality disturbances that occurs when there is disappearance of the voltages supply, and it can also be indicated as temporary, momentary, or sustained voltage interruptions.
Under voltage This is a decrease of root mean square (RMS) AC voltage typically less than 90.
Over voltage The over voltage occurs when the (RMS) has increased to more than 110of rated voltage. ( Baggini, 2007).
However, under power quality events, there are various power disturbances that occur.
Noise In the power system, noise can occur when there is occurrence of unwanted electrical signals, which is capable of providing undesirable effects to the circuits.
Flicker The flicker occurs when there is short duration of voltage that occurs because of short circuit, switching and load changing.
Notching The notching occurs when there are disturbances in normal power voltage waveform. This waveform usually last for less than a half cycle.(Winter, 1976, Sankaran, 2002).
Harmonics The term harmonic refer to the distortion of power supply due to the increase in the non-linear loads. Harmonic distortion is the deviation from the voltage and from the current supplied that lead to the disturbances in power supply. Typically, this has been classified as a typical example of variation in power quality. Harmonic is one of the leading causes of voltage distortions, and the effect usually results to severe voltage unbalance. With harmonic voltage distortion, the electric loads can be negatively affected because notching caused by harmonic waveform.
With negative effect caused by harmonics, the harmonic has become a leading cause of losses in the high tech business. Typically, a major objective of designing electric power system is to generate electrical energy as well as delivering the acceptable energy system with acceptable voltage to the end users. However, by supplying acceptable energy system to end users, there is also need to achieve optimal level of returns from the electrical investment. (Bollen, 2003). It is essential to realise that power quality is an integral part of encouraging a power providers to supply electricity with power efficiency. (Li, Wang and Zhang, 2007).
Despite the intention of power distributor in supplying the standard power quality, there are situations where there can be deviations from quality of voltage or quality of current supplied to end users, which is lead to the harmonic distortion.
To provide relevant understanding on the effect harmonics and power quality, the study provides research aim.
Research Aims
The aims of this study are as follows
To provide relevant understanding on the effectiveness of harmonics and the electrical power system network to the end-users.
To provide relevant solution by evaluating the harmonics and the electrical power system network.
In order to provide relevant solution for the enhancement of power quality and to provide solution to harmonic distortions, the paper identifies problem related to the project.
Problem identification
To achieve ideal power quality supply, there is need to achieve electrical power energy that is characterised with constant voltage, perfect waveform and perfect frequency with little or no interruptions. Thus, it is essential to note that power provider intends to fulfill the power quality, however, in practice it is very difficult to achieve ideal power quality since harmonic is one of the major factors that distort the essential supply of power quality. Typically, the problem caused by harmonic has led to the changes in the supply of power, and distortion of shape of electrical waveforms as well as leading to the distortion of power supply, and this has caused disturbances to power quality in several forms. (Shah, 2005).
Liu and Heydt (2005) argued that harmonic components which comprise of dc-biased transformers or three-phase rectifiers can cause unequal negative and positive values that are capable of leading to waveform asymmetry. Typically, the waveform asymmetry is a source of harmful effects that lead to peak in current or load to voltages, and these effects are the leading to the indices in power quality that range from harmonic distortion to telephone inference factor.
The identification of harmonic problems that cause dissatisfaction to the end users generates research problem that this study attempts to address. To enhance greater understanding on the effectiveness of harmonic to the electrical network power system as well as providing solution to the problem generated by harmonic distortion, the paper reviews the previous literatures related to the study.
Review of literatures
This section provides the review of relevant literatures which examines the background of power quality and harmonic. The literatures also reviews the problems generated by the harmonic that has led to the power quality problem to the end users. Finally, the literatures evaluate the problem and provide the possible solution.
Review of background of study
Several definitions have been proposed for power quality. The Institute of Electrical and Electronics Engineers (2009) defines power quality as the different varieties of electromagnetic phenomena, which include characteristics of current and voltage at a given location and at any given time. In recent years, the increase in the wide varieties of the application of the electrical and electronic equipments has made many scholars to heightened special interest in power quality.
Bayliss and Hardy (2006) refer to power quality as the purity of current waveform and purity of voltage. The disturbances in power quality is the deviation from pure form of sinusoidal. It is essential to realise that harmonic is one such deviation that has effect on power supply systems. On the other hand, Parihar and Liu (1999) define power quality as the satisfaction that the energy user could derive from the energy provider. Typically, from the perspective of energy provider, the power quality is the measure of service that the energy provider provides to their customers.
Analysis of various definitions provided on power quality reveals that it is impossible to achieve ideal power quality where there would be unispectral voltage signal with constant magnitude in 365 days a year. It essential to realise that various factors are known to deteriorate the achievement of power quality one of the major causes is harmonics.
Scholars have provided different definitions for harmonics. Shah (2005) defines harmonics as the signal content where its frequency is an integral part of multiple and fundamental frequencys system. It is essential to realise that the presence of harmonic in the waveform distorts the shape of waveform of an electrical current and voltage current. It also causes many disturbances in the electrical supply. Looking at fig 1, it is revealed that harmonic can caused untold distortion to electrical current.
The growing concern in achieving the power quality is the distortion in harmonics which is caused by the non-linearity of electrical loads generated by consumers. The consumers load range from industrial sectors that manufacture equipments and consumers who utilise electricity for personal use. The problems of these overload lead to the harmonic voltage distortion that can lead to the damage of electrical transformers, heating of neutral wire. In addition, the harmonic distortion can make computer to exhibit data error or total loss of data. (Shah, 2005). The illustration in fig 2 is typical example of loads in home and offices.
Fig 2 loads at home and offices
In addition, the Institute of Electrical and Electronics Engineers (2009) also supported the argument of previous authors by pointing out that with the combination of voltage and current, harmonic cause the waveform distortion to the based electronic equipment.
With the problem generated by harmonics, it is essential to realise that it will be impossible to achieve an ideal power quality to the end users. In the next section, the paper review literatures that examine the harmonics effects to the electrical power system network and to the end-users.
Harmonics effects to the electrical power system network and to the end-users
There are various effects generated by the harmonics to the power system network and to end-users. Many users have revealed their dissatisfaction with the electrical network that has been provided to them. Gopalakrishnan, Udayakumar, and Raghavendiran (2002) pointed out that power quality and harmonic have become the major concerns to consumers. The growing concerned has been generated as a result of poor quality of power supply that consumers and utilities receive from electric power providers. The authors further pointed out that based on the field study conducted on several consumers of power it is revealed that harmonics are the predominant problems that many of consumers complained. Typically, the views recorded from the consumers perspectives have revealed that harmonics are the sources of damage to cables, failure of electrical fuse, losses in the quality of transformers, and malfunctions of electrical relay systems. It is essential to realize there are standard laid down by IEEE 519, which indicates absolute standard on the level of harmonics current that can be injected into the electrical power system network based on the size of consumers.
The harmonic that is above the size of consumers can lead to the heating effects of power equipments, and disruption of electronically controlled equipments. (Shah, 2005).
Bollen (2003) employed a mathematical formula to argue that harmonic is the decomposition of non-sinusoidal, which is from period signal of component and sum of sinusoidal
From the mathematical illustration, it is revealed that the Ah and h amplitude and h, f01T and T the period can be deducted to refer to the phase of angle of harmonic order. Meanwhile, the power system that is operating at 50 Hz and current that is decomposed to (50 Hz) are the sum of component and the component of harmonic number that lead to the frequencies of multiple integers of 50 Hz. Thus, h3 (150-Hz component) has been referred to the harmonic distortion, which is referred to the period power system of power system frequency (50 or 60 Hz). (Bollen, 2003). The argument of Rash (1998) revealed that harmonics in supply network is a new phenomenon in the field of electrical engineering. One of the major reasons that led many researchers to focus their interest on the harmonics is the dissatisfaction that caused to the end users. Typically, the harmonic has become one of the devastating problems where the parameter of supplied network has led to the damaging problems. Despite the problem being caused by harmonics, it is essential to understand the power network before being able to monitor the specific problems caused by harmonic distortions.
Thus, network disturbances are an issue that is increasing important in power quality. The classification of network disturbances has revealed that network failure can cause voltage sags, and harmonic voltage distortion. Based on the law of electricity, the network disturbances have been one of the normal phenomena in the electrical network. Although, the 18 kV network has been noted to be one of the backbone of distribution of energy, however, the distortion of network can come from voltage harmonic distortion. (Kahle).
Thus, the network failure has been an increased concern to the modern day industries, which are the major consumers of power. Typically, many industrial facilities are demanding for better services in the electricity supply. The increased in the sensitivity of consumers is as a result of consequences of bad electric network that has led to the damage of organisational equipments as well as loss of production and loss of market due to degradation of equipment caused by harmonic network system. The survey carried out by Bechtel Consulting on the feedback of consumers on quality of power provided, it is revealed that 87 of consumers were primarily concerned about power quality.
With negative effect experienced by consumers due to the effect harmonic distortions, the literatures provide solution to the harmonic problems.
Solution to the harmonic problems
The quality constant supply of electricity is the backbone of technological development of any country. Although, literatures have revealed that ideal power quality is impossible to achieve, however, there is still need to achieve maximum power quality in order to provide highest satisfaction to the end users. Scholars have provided several solutions to the enhancement of power quality. Shah (2005) explained that in order to provide solution to the problem of power quality, it is essential to look for solution that is cost effective, that will not lead to the loss of production and minimise equipment downturn. Typically, these objectives could be achieved by taking some minor precautions such as taking some time to monitor the electrical devices regularly. For example, to achieve power quality, it is essential for consumers as well as service providers to make use of quality equipments. The instruments such as analyser model PHT 4545 could be employed to carry out periodic inspection on the consumers and industrial sector in order to monitor the use of quality instruments.
Despite the solution presented by the author, the achievement of this objective will take a long time. For instance, there is need for the full cooperation of manufacturers and the end users. (Khan).The information derived from this analysis could help the power quality experts to identify the cause and source of power quality problems, and this will help the power quality experts to avoid the disturbances when identified.
Apostolov (2007) also suggested that electric power-systems monitoring is an ideal method of providing solution to the power harmonic distortion, which is one of the leading cause of power quality. The use of IEC 61850 could be employed to monitor, control and protect the electrical devices. Typically, with the use of intelligent electronic devices (IEDs), this will help in detecting and record different abnormal devices in the electronic equipments. The IED possess multifunctional capability to monitor disturbances, and waveform that can lead to power quality problems.
Golkar also supported the monitoring the power quality by arguing that many surveys have been able to reveal the key opportunity that can be derived from monitoring of power quality because it will make the utility to protect its reputation and be able to improve customers satisfaction. Typically,
power quality monitoring is an essential service many utilities perform for their industrial
and other key commercial customers. Because of the technology and software now
available this monitoring is highly effective. Not only can a monitoring system provide
information about the quality of the power and the causes of power system disturbances,
but it can identify problem condition throughout the system before they cause
widespread customer complaints, equipment malfunction, and even equipment
failures.(Golkar, p 1).
Despite the advantages that can be derived on monitoring devices in eliminating the harmonic distortion, the effectiveness of this solution depends on consumers awareness before monitoring could be a solution to the harmonic problem. This also depends on the consumers technical knowledge on power quality and harmonic problems. Essentially, it is the consumers awareness and consumers technical knowledge that can bring about the move to monitor the power system in order to detect the harmonic instructions. To support this argument, Liu (1999) pointed out that consumers knowledge on power quality is very essential because there are differences in what different consumers think about power quality. The energy providers need to educate consumers about the power quality and harmonic problems. Since it is impossible for energy providers to provide ideal power quality to consumers. It is essential for the energy providers to help customers in exploring the various mitigation that can cause power problems, and the energy providers should educate customers about the advantages of making use of quality equipments in order to minimise the power quality problem. Although this solution is ideal, however it is not comprehensive enough. Bollen (2003) provides comprehensive solution to the harmonic problem. The author pointed out that to mitigate the problems caused by harmonics there is View Within Artic
need to improve network design and operation. Typically, there is need to redesign the network power system so that the harmonic problems will not affect certain locations in the industrial power systems. The author further argued that the voltage dips could be mitigated by connecting Uninterruptible Power Supply (UPS), and the DVR (dynamic voltage restorer). These are ideal to mitigate the harmonic problem with voltage transformer carrying big load.
Additional, customers relationship with power provider is essential to provide quality power supply to consumers. As being pointed out by Li,Wang,. Zhang, (2007), it is important for power provider to satisfy customers through adoption of customer relationship management (CRM). The author further argued that CRM can enhance high degree of customers satisfaction, and this will lead to improvement of service towards customers. Typically, the primary mission of CRM in power supply enterprise is to study customers consuming electric power characteristic and the rule, which helps to design consume power plan to meet customer satisfaction corresponding. (Li,Wang,. Zhang, 2007, p. 584).
However, analysis of literature is not enough, there is need to collect data through research methodology in order to provide a greater understanding on the harmonics effectiveness to the electrical power system network and to the end-users.
Investigation methodology
This section provides method of data collection through investigation methodology. Since the aim of this dissertation is to investigate the harmonics effectiveness to the electrical power system network and to the end-users, the study collects data through the secondary research which involves analysis of previous literatures related to the study.
Research design
A research design consists of framework by which data for the dissertation are collected. The paper collets data through secondary research which involve reviewing of previous literatures. The secondary research is employed in order to provide greater understanding on the harmonics effectiveness to the electrical power system network and to the end-users.
Methods
The dissertation employs secondary research method for data collection. The secondary research involves analysis of previous literatures that deal with harmonic and power quality. There are several advantages attributed to secondary research. Apart that the researchers will be able to have access to large collection of data, the secondary research offers inexpensive method of data collection. Castle (2003) pointed out that
The primary advantage of secondary research is its potential for resource
savings and cost- effectiveness. Often, the database provides the investigator
with access to information that took months or even longer to collect. Hiring and
paying personnel to collect data are eliminated, and with adequate computer
storage and memory, the investigator can reduce the number of additional
support persons required. Secondary research also circumvents other data
collection challenges such as finding appropriate participants and obtaining
large enough sample sizes to yield convincing results. (p3)
Thus, the research employs secondary research to search literatures that explore the harmonics effectiveness to the electrical power system network and to the end-users. The previous studies are also reviewed to provide solution to the harmonic problems to the end users. The researcher will search several electronic databases to collect data through secondary research. Essentially, the electronic database contains different collections of research articles in electrical engineering that deal with power quality and harmonic. To ensure that the required literatures relevant to the study are obtained, the researcher search electronic database that deal with the collection of highest quality literatures on electrical engineering. For example, the database of IEEE Xplore will be searched. The database of science direct and the Wiley InterScience database will also be searched to obtain relevant literatures for the study. To supplement this database, the researcher will search other electronic databases such as research articles from the universities libraries and Emerald database. To source for literatures that are uniquely relevant to the study, the paper employs keywords to search for literatures from these databases. The keywords employed are power quality, harmonics, consumers, power providers, electrical power system network, and costumers perceptions. To ensure that the data collected are valid and reliable. The studies analyses data and the procedure to carry out data analysis are discussed in the next section.
Analysis and Discussion
The sections provide analysis of the data that will be collected through secondary research. The essential purpose of carrying out data analysis is to enhance data reliability and data credibility through data accuracy. Moreover, summary of the dissertation through discussion is presented in this section.
Data Analysis
The data collected through secondary research are analysed in order to enhance data credibility. As discussed in the previous section, the study attempts to collect data through secondary research method. To ensure data analysis of secondary research, the researchers will ensure that all the research articles that will be used for this study are sourced from reputable journals and the research articles sources from these journals are relevant to the study. (Trochim, Donnelly 2007, Designed Method Dillman, 2000)
Discussion
Customers satisfaction is essential for the continuation of customers participation. Meanwhile, provision of ideal power quality is essential in order to increase customers patronage towards organisations. While ideal power quality is impossible to achieve in real life situation, the optimum power quality is essential for the enhancement of customers satisfaction. Although, energy provider may be willing to satisfy consumers with provision of power quality. However, the analysis of literatures has revealed that harmonics are one of the major contributors of power quality problems. Thus, the contributing problems of harmonics have made the harmonic and power quality to be one of the most important topics in electrical engineering. Studies have centred on this line of research because harmonic voltages distortion has caused many untold dissatisfaction to many users. Its effects range from the unbalance in the voltage to distortion of rotation machines that many industrial sectors use for production.
With effect of harmonic that lead to the dissatisfaction of end users, it has been argued whether energy providers could provide the satisfactory power quality that customers need.
Conclusion and Recommendations
The problem caused by harmonic has been revealed to cause detrimental effect to power system engineers because of the harmonic effect on the apparatus. The effects of harmonic have led the study to call for industrial standard for the implementation of power quality. The increase in the linear load on the electrical power system necessitates the identification, and mitigation of harmonic problems. To provide adequate quality planning to satisfy the end users, this study attempts to investigate the harmonics effectiveness to the electrical power network system and to the end-users. To provide greater understanding on the research aim, the study has examined the following section.
Section one provides the introduction of the study. This section provides the research aim. In the introduction, the overview of the study is explored in order to provide overall picture of what the research attempts to investigate.
Section two provides statement of problem, which discusses the problem that the dissertation attempts to solve. Essentially, the harmonic problem is a big issue in electrical engineering, and to identify the problem associated with harmonic, the section provides the problem associated with power quality.
Section three reviews previous literatures related to the study. The literatures overviewed the harmonic and power quality. The literature also reviewed harmonics effects to the electrical power system network and to the end-users, and the solution created by harmonic problems are suggested.
Section four of the study provides methodology that describes method of data collection.
Section five also provides analysis and discussion.
Meanwhile, to provide path for future research, there is need to provide recommendation to alleviate harmonic problems.
Recommendations
Customers satisfaction is essential for the organisational growth. In relation to power supply, customers perceptions can influence the customers patronage, and this can affect organisational market advantages. To mitigate harmonic problems and enhance customers satisfactions, the dissertations provide the following recommendation.
First, the energy provider should replace their ageing equipments they use to supply power to customers.
In addition, the Institute of Electrical and Electronic Engineers (IEEE) needs to redefine the harmonic standard in order to eliminate various voltage sags and voltage swells.
To enhance greater understanding on harmonic distortion and its effects on consumers, there is need to carry out survey in order to investigate the harmonics effectiveness to the electrical power system network and to the end-users. The sample population for the survey should be consumers of electrical supply. The manufacturing companies that consume large amount of electricity should also be targeted for future survey. The sample populations should also contain other companies in industrial sectors.
There is also need to conduct a case study on power quality and harmonic distortions experience on consumers in order to enhance greater understanding on power quality and harmonics effectiveness to the electrical power system network and to the end-users.
Finally, there is need for further research on the development of sophisticated equipment that the energy provider could be used to enhance power quality for the satisfaction of their customers.
Recently, there is growing increase in the number of consumers who demand for more quality power systems in order to maximise their total utility. The major reason is that consumers have become increasingly aware of their right to demand for reliable, low cost and high quality energy systems for the industrial and domestic uses. To satisfy customers demand, energy providers have employed several devices in providing power quality to customers. For example, energy providers are shifting away from large power stations to small units in order generates energy with a lower voltage. Typically, customers satisfactions is an integral part of organisational growth, and many energy providers have realised that provision of power quality is very essential to retain existing customers, and attract new customers.
To enhance greater understanding of power quality, there is need to illustrate the term power quality.
Overview of power quality
The term power quality is the combination of quality from voltage and quality supplied from current. To achieve power quality, current quality should complement with voltage quality where quality of power supplied should involve ideal non-technical interaction from network of power to customers. To provide essential power quality to consumers, the energy providers need to supply accepted electrical energy to consumers without power interruption.
Typically, there are different phenomena of power quality. These phenomena are categorised as follows
1. Power quality events
2. Power quality variations
Although, there are no noticeable difference between the two phenomena. The term variation occurs when there are continuous disturbances in the energy system while event occurs when there are infrequent disturbances.
Under power quality event, there are various power disturbances that occur.
Voltage Sag or Voltage dip This occurs when there is reduction of AC voltage from half to little duration. This consequence can cause motor to start and switching an electronic loads.
Voltage swell This occurs when there is increase in power frequency of AC voltage from half to little duration.
Voltage surge The power quality disturbances occur when there is a sharp increase in current or voltage.
Voltage unbalance This occurs when there is imbalance between the percentage ratio of negative sequence and ratio of positive component.
Transient The disturbances occur when there is unanticipated change in voltage which happens by unprecedented occurrence.
Voltage interruption This is a kind of power quality disturbances that occurs when there is disappearance of the voltages supply, and it can also be indicated as temporary, momentary, or sustained voltage interruptions.
Under voltage This is a decrease of root mean square (RMS) AC voltage typically less than 90.
Over voltage The over voltage occurs when the (RMS) has increased to more than 110of rated voltage. ( Baggini, 2007).
However, under power quality events, there are various power disturbances that occur.
Noise In the power system, noise can occur when there is occurrence of unwanted electrical signals, which is capable of providing undesirable effects to the circuits.
Flicker The flicker occurs when there is short duration of voltage that occurs because of short circuit, switching and load changing.
Notching The notching occurs when there are disturbances in normal power voltage waveform. This waveform usually last for less than a half cycle.(Winter, 1976, Sankaran, 2002).
Harmonics The term harmonic refer to the distortion of power supply due to the increase in the non-linear loads. Harmonic distortion is the deviation from the voltage and from the current supplied that lead to the disturbances in power supply. Typically, this has been classified as a typical example of variation in power quality. Harmonic is one of the leading causes of voltage distortions, and the effect usually results to severe voltage unbalance. With harmonic voltage distortion, the electric loads can be negatively affected because notching caused by harmonic waveform.
With negative effect caused by harmonics, the harmonic has become a leading cause of losses in the high tech business. Typically, a major objective of designing electric power system is to generate electrical energy as well as delivering the acceptable energy system with acceptable voltage to the end users. However, by supplying acceptable energy system to end users, there is also need to achieve optimal level of returns from the electrical investment. (Bollen, 2003). It is essential to realise that power quality is an integral part of encouraging a power providers to supply electricity with power efficiency. (Li, Wang and Zhang, 2007).
Despite the intention of power distributor in supplying the standard power quality, there are situations where there can be deviations from quality of voltage or quality of current supplied to end users, which is lead to the harmonic distortion.
To provide relevant understanding on the effect harmonics and power quality, the study provides research aim.
Research Aims
The aims of this study are as follows
To provide relevant understanding on the effectiveness of harmonics and the electrical power system network to the end-users.
To provide relevant solution by evaluating the harmonics and the electrical power system network.
In order to provide relevant solution for the enhancement of power quality and to provide solution to harmonic distortions, the paper identifies problem related to the project.
Problem identification
To achieve ideal power quality supply, there is need to achieve electrical power energy that is characterised with constant voltage, perfect waveform and perfect frequency with little or no interruptions. Thus, it is essential to note that power provider intends to fulfill the power quality, however, in practice it is very difficult to achieve ideal power quality since harmonic is one of the major factors that distort the essential supply of power quality. Typically, the problem caused by harmonic has led to the changes in the supply of power, and distortion of shape of electrical waveforms as well as leading to the distortion of power supply, and this has caused disturbances to power quality in several forms. (Shah, 2005).
Liu and Heydt (2005) argued that harmonic components which comprise of dc-biased transformers or three-phase rectifiers can cause unequal negative and positive values that are capable of leading to waveform asymmetry. Typically, the waveform asymmetry is a source of harmful effects that lead to peak in current or load to voltages, and these effects are the leading to the indices in power quality that range from harmonic distortion to telephone inference factor.
The identification of harmonic problems that cause dissatisfaction to the end users generates research problem that this study attempts to address. To enhance greater understanding on the effectiveness of harmonic to the electrical network power system as well as providing solution to the problem generated by harmonic distortion, the paper reviews the previous literatures related to the study.
Review of literatures
This section provides the review of relevant literatures which examines the background of power quality and harmonic. The literatures also reviews the problems generated by the harmonic that has led to the power quality problem to the end users. Finally, the literatures evaluate the problem and provide the possible solution.
Review of background of study
Several definitions have been proposed for power quality. The Institute of Electrical and Electronics Engineers (2009) defines power quality as the different varieties of electromagnetic phenomena, which include characteristics of current and voltage at a given location and at any given time. In recent years, the increase in the wide varieties of the application of the electrical and electronic equipments has made many scholars to heightened special interest in power quality.
Bayliss and Hardy (2006) refer to power quality as the purity of current waveform and purity of voltage. The disturbances in power quality is the deviation from pure form of sinusoidal. It is essential to realise that harmonic is one such deviation that has effect on power supply systems. On the other hand, Parihar and Liu (1999) define power quality as the satisfaction that the energy user could derive from the energy provider. Typically, from the perspective of energy provider, the power quality is the measure of service that the energy provider provides to their customers.
Analysis of various definitions provided on power quality reveals that it is impossible to achieve ideal power quality where there would be unispectral voltage signal with constant magnitude in 365 days a year. It essential to realise that various factors are known to deteriorate the achievement of power quality one of the major causes is harmonics.
Scholars have provided different definitions for harmonics. Shah (2005) defines harmonics as the signal content where its frequency is an integral part of multiple and fundamental frequencys system. It is essential to realise that the presence of harmonic in the waveform distorts the shape of waveform of an electrical current and voltage current. It also causes many disturbances in the electrical supply. Looking at fig 1, it is revealed that harmonic can caused untold distortion to electrical current.
The growing concern in achieving the power quality is the distortion in harmonics which is caused by the non-linearity of electrical loads generated by consumers. The consumers load range from industrial sectors that manufacture equipments and consumers who utilise electricity for personal use. The problems of these overload lead to the harmonic voltage distortion that can lead to the damage of electrical transformers, heating of neutral wire. In addition, the harmonic distortion can make computer to exhibit data error or total loss of data. (Shah, 2005). The illustration in fig 2 is typical example of loads in home and offices.
Fig 2 loads at home and offices
In addition, the Institute of Electrical and Electronics Engineers (2009) also supported the argument of previous authors by pointing out that with the combination of voltage and current, harmonic cause the waveform distortion to the based electronic equipment.
With the problem generated by harmonics, it is essential to realise that it will be impossible to achieve an ideal power quality to the end users. In the next section, the paper review literatures that examine the harmonics effects to the electrical power system network and to the end-users.
Harmonics effects to the electrical power system network and to the end-users
There are various effects generated by the harmonics to the power system network and to end-users. Many users have revealed their dissatisfaction with the electrical network that has been provided to them. Gopalakrishnan, Udayakumar, and Raghavendiran (2002) pointed out that power quality and harmonic have become the major concerns to consumers. The growing concerned has been generated as a result of poor quality of power supply that consumers and utilities receive from electric power providers. The authors further pointed out that based on the field study conducted on several consumers of power it is revealed that harmonics are the predominant problems that many of consumers complained. Typically, the views recorded from the consumers perspectives have revealed that harmonics are the sources of damage to cables, failure of electrical fuse, losses in the quality of transformers, and malfunctions of electrical relay systems. It is essential to realize there are standard laid down by IEEE 519, which indicates absolute standard on the level of harmonics current that can be injected into the electrical power system network based on the size of consumers.
The harmonic that is above the size of consumers can lead to the heating effects of power equipments, and disruption of electronically controlled equipments. (Shah, 2005).
Bollen (2003) employed a mathematical formula to argue that harmonic is the decomposition of non-sinusoidal, which is from period signal of component and sum of sinusoidal
From the mathematical illustration, it is revealed that the Ah and h amplitude and h, f01T and T the period can be deducted to refer to the phase of angle of harmonic order. Meanwhile, the power system that is operating at 50 Hz and current that is decomposed to (50 Hz) are the sum of component and the component of harmonic number that lead to the frequencies of multiple integers of 50 Hz. Thus, h3 (150-Hz component) has been referred to the harmonic distortion, which is referred to the period power system of power system frequency (50 or 60 Hz). (Bollen, 2003). The argument of Rash (1998) revealed that harmonics in supply network is a new phenomenon in the field of electrical engineering. One of the major reasons that led many researchers to focus their interest on the harmonics is the dissatisfaction that caused to the end users. Typically, the harmonic has become one of the devastating problems where the parameter of supplied network has led to the damaging problems. Despite the problem being caused by harmonics, it is essential to understand the power network before being able to monitor the specific problems caused by harmonic distortions.
Thus, network disturbances are an issue that is increasing important in power quality. The classification of network disturbances has revealed that network failure can cause voltage sags, and harmonic voltage distortion. Based on the law of electricity, the network disturbances have been one of the normal phenomena in the electrical network. Although, the 18 kV network has been noted to be one of the backbone of distribution of energy, however, the distortion of network can come from voltage harmonic distortion. (Kahle).
Thus, the network failure has been an increased concern to the modern day industries, which are the major consumers of power. Typically, many industrial facilities are demanding for better services in the electricity supply. The increased in the sensitivity of consumers is as a result of consequences of bad electric network that has led to the damage of organisational equipments as well as loss of production and loss of market due to degradation of equipment caused by harmonic network system. The survey carried out by Bechtel Consulting on the feedback of consumers on quality of power provided, it is revealed that 87 of consumers were primarily concerned about power quality.
With negative effect experienced by consumers due to the effect harmonic distortions, the literatures provide solution to the harmonic problems.
Solution to the harmonic problems
The quality constant supply of electricity is the backbone of technological development of any country. Although, literatures have revealed that ideal power quality is impossible to achieve, however, there is still need to achieve maximum power quality in order to provide highest satisfaction to the end users. Scholars have provided several solutions to the enhancement of power quality. Shah (2005) explained that in order to provide solution to the problem of power quality, it is essential to look for solution that is cost effective, that will not lead to the loss of production and minimise equipment downturn. Typically, these objectives could be achieved by taking some minor precautions such as taking some time to monitor the electrical devices regularly. For example, to achieve power quality, it is essential for consumers as well as service providers to make use of quality equipments. The instruments such as analyser model PHT 4545 could be employed to carry out periodic inspection on the consumers and industrial sector in order to monitor the use of quality instruments.
Despite the solution presented by the author, the achievement of this objective will take a long time. For instance, there is need for the full cooperation of manufacturers and the end users. (Khan).The information derived from this analysis could help the power quality experts to identify the cause and source of power quality problems, and this will help the power quality experts to avoid the disturbances when identified.
Apostolov (2007) also suggested that electric power-systems monitoring is an ideal method of providing solution to the power harmonic distortion, which is one of the leading cause of power quality. The use of IEC 61850 could be employed to monitor, control and protect the electrical devices. Typically, with the use of intelligent electronic devices (IEDs), this will help in detecting and record different abnormal devices in the electronic equipments. The IED possess multifunctional capability to monitor disturbances, and waveform that can lead to power quality problems.
Golkar also supported the monitoring the power quality by arguing that many surveys have been able to reveal the key opportunity that can be derived from monitoring of power quality because it will make the utility to protect its reputation and be able to improve customers satisfaction. Typically,
power quality monitoring is an essential service many utilities perform for their industrial
and other key commercial customers. Because of the technology and software now
available this monitoring is highly effective. Not only can a monitoring system provide
information about the quality of the power and the causes of power system disturbances,
but it can identify problem condition throughout the system before they cause
widespread customer complaints, equipment malfunction, and even equipment
failures.(Golkar, p 1).
Despite the advantages that can be derived on monitoring devices in eliminating the harmonic distortion, the effectiveness of this solution depends on consumers awareness before monitoring could be a solution to the harmonic problem. This also depends on the consumers technical knowledge on power quality and harmonic problems. Essentially, it is the consumers awareness and consumers technical knowledge that can bring about the move to monitor the power system in order to detect the harmonic instructions. To support this argument, Liu (1999) pointed out that consumers knowledge on power quality is very essential because there are differences in what different consumers think about power quality. The energy providers need to educate consumers about the power quality and harmonic problems. Since it is impossible for energy providers to provide ideal power quality to consumers. It is essential for the energy providers to help customers in exploring the various mitigation that can cause power problems, and the energy providers should educate customers about the advantages of making use of quality equipments in order to minimise the power quality problem. Although this solution is ideal, however it is not comprehensive enough. Bollen (2003) provides comprehensive solution to the harmonic problem. The author pointed out that to mitigate the problems caused by harmonics there is View Within Artic
need to improve network design and operation. Typically, there is need to redesign the network power system so that the harmonic problems will not affect certain locations in the industrial power systems. The author further argued that the voltage dips could be mitigated by connecting Uninterruptible Power Supply (UPS), and the DVR (dynamic voltage restorer). These are ideal to mitigate the harmonic problem with voltage transformer carrying big load.
Additional, customers relationship with power provider is essential to provide quality power supply to consumers. As being pointed out by Li,Wang,. Zhang, (2007), it is important for power provider to satisfy customers through adoption of customer relationship management (CRM). The author further argued that CRM can enhance high degree of customers satisfaction, and this will lead to improvement of service towards customers. Typically, the primary mission of CRM in power supply enterprise is to study customers consuming electric power characteristic and the rule, which helps to design consume power plan to meet customer satisfaction corresponding. (Li,Wang,. Zhang, 2007, p. 584).
However, analysis of literature is not enough, there is need to collect data through research methodology in order to provide a greater understanding on the harmonics effectiveness to the electrical power system network and to the end-users.
Investigation methodology
This section provides method of data collection through investigation methodology. Since the aim of this dissertation is to investigate the harmonics effectiveness to the electrical power system network and to the end-users, the study collects data through the secondary research which involves analysis of previous literatures related to the study.
Research design
A research design consists of framework by which data for the dissertation are collected. The paper collets data through secondary research which involve reviewing of previous literatures. The secondary research is employed in order to provide greater understanding on the harmonics effectiveness to the electrical power system network and to the end-users.
Methods
The dissertation employs secondary research method for data collection. The secondary research involves analysis of previous literatures that deal with harmonic and power quality. There are several advantages attributed to secondary research. Apart that the researchers will be able to have access to large collection of data, the secondary research offers inexpensive method of data collection. Castle (2003) pointed out that
The primary advantage of secondary research is its potential for resource
savings and cost- effectiveness. Often, the database provides the investigator
with access to information that took months or even longer to collect. Hiring and
paying personnel to collect data are eliminated, and with adequate computer
storage and memory, the investigator can reduce the number of additional
support persons required. Secondary research also circumvents other data
collection challenges such as finding appropriate participants and obtaining
large enough sample sizes to yield convincing results. (p3)
Thus, the research employs secondary research to search literatures that explore the harmonics effectiveness to the electrical power system network and to the end-users. The previous studies are also reviewed to provide solution to the harmonic problems to the end users. The researcher will search several electronic databases to collect data through secondary research. Essentially, the electronic database contains different collections of research articles in electrical engineering that deal with power quality and harmonic. To ensure that the required literatures relevant to the study are obtained, the researcher search electronic database that deal with the collection of highest quality literatures on electrical engineering. For example, the database of IEEE Xplore will be searched. The database of science direct and the Wiley InterScience database will also be searched to obtain relevant literatures for the study. To supplement this database, the researcher will search other electronic databases such as research articles from the universities libraries and Emerald database. To source for literatures that are uniquely relevant to the study, the paper employs keywords to search for literatures from these databases. The keywords employed are power quality, harmonics, consumers, power providers, electrical power system network, and costumers perceptions. To ensure that the data collected are valid and reliable. The studies analyses data and the procedure to carry out data analysis are discussed in the next section.
Analysis and Discussion
The sections provide analysis of the data that will be collected through secondary research. The essential purpose of carrying out data analysis is to enhance data reliability and data credibility through data accuracy. Moreover, summary of the dissertation through discussion is presented in this section.
Data Analysis
The data collected through secondary research are analysed in order to enhance data credibility. As discussed in the previous section, the study attempts to collect data through secondary research method. To ensure data analysis of secondary research, the researchers will ensure that all the research articles that will be used for this study are sourced from reputable journals and the research articles sources from these journals are relevant to the study. (Trochim, Donnelly 2007, Designed Method Dillman, 2000)
Discussion
Customers satisfaction is essential for the continuation of customers participation. Meanwhile, provision of ideal power quality is essential in order to increase customers patronage towards organisations. While ideal power quality is impossible to achieve in real life situation, the optimum power quality is essential for the enhancement of customers satisfaction. Although, energy provider may be willing to satisfy consumers with provision of power quality. However, the analysis of literatures has revealed that harmonics are one of the major contributors of power quality problems. Thus, the contributing problems of harmonics have made the harmonic and power quality to be one of the most important topics in electrical engineering. Studies have centred on this line of research because harmonic voltages distortion has caused many untold dissatisfaction to many users. Its effects range from the unbalance in the voltage to distortion of rotation machines that many industrial sectors use for production.
With effect of harmonic that lead to the dissatisfaction of end users, it has been argued whether energy providers could provide the satisfactory power quality that customers need.
Conclusion and Recommendations
The problem caused by harmonic has been revealed to cause detrimental effect to power system engineers because of the harmonic effect on the apparatus. The effects of harmonic have led the study to call for industrial standard for the implementation of power quality. The increase in the linear load on the electrical power system necessitates the identification, and mitigation of harmonic problems. To provide adequate quality planning to satisfy the end users, this study attempts to investigate the harmonics effectiveness to the electrical power network system and to the end-users. To provide greater understanding on the research aim, the study has examined the following section.
Section one provides the introduction of the study. This section provides the research aim. In the introduction, the overview of the study is explored in order to provide overall picture of what the research attempts to investigate.
Section two provides statement of problem, which discusses the problem that the dissertation attempts to solve. Essentially, the harmonic problem is a big issue in electrical engineering, and to identify the problem associated with harmonic, the section provides the problem associated with power quality.
Section three reviews previous literatures related to the study. The literatures overviewed the harmonic and power quality. The literature also reviewed harmonics effects to the electrical power system network and to the end-users, and the solution created by harmonic problems are suggested.
Section four of the study provides methodology that describes method of data collection.
Section five also provides analysis and discussion.
Meanwhile, to provide path for future research, there is need to provide recommendation to alleviate harmonic problems.
Recommendations
Customers satisfaction is essential for the organisational growth. In relation to power supply, customers perceptions can influence the customers patronage, and this can affect organisational market advantages. To mitigate harmonic problems and enhance customers satisfactions, the dissertations provide the following recommendation.
First, the energy provider should replace their ageing equipments they use to supply power to customers.
In addition, the Institute of Electrical and Electronic Engineers (IEEE) needs to redefine the harmonic standard in order to eliminate various voltage sags and voltage swells.
To enhance greater understanding on harmonic distortion and its effects on consumers, there is need to carry out survey in order to investigate the harmonics effectiveness to the electrical power system network and to the end-users. The sample population for the survey should be consumers of electrical supply. The manufacturing companies that consume large amount of electricity should also be targeted for future survey. The sample populations should also contain other companies in industrial sectors.
There is also need to conduct a case study on power quality and harmonic distortions experience on consumers in order to enhance greater understanding on power quality and harmonics effectiveness to the electrical power system network and to the end-users.
Finally, there is need for further research on the development of sophisticated equipment that the energy provider could be used to enhance power quality for the satisfaction of their customers.
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