Monitoring System Of Transformer Engineering Essay

Monitoring System Of Transformer Engineering Essay Transformers have a long service life if they are operated at its full load conditions. However, their life is significantly reduced if they are overloaded, resulting in unexpected failures and loss of supply to a large number of customers thus effecting system reliability. Overloading and ineffective cooling of transformers are the major causes of failure in distribution transformers. Transformer follows Bath-curve relation type curve (Fig no. 1) for taking place fault in it. FIG. NO 1 BATH -CURVE The first phase indicates fault occurring due to improper service handling of transformer because it is new, second phase indicates fault occurring constantly and third phase fault are due aging problems. [5] Online monitoring of key operational parameters of transformers can provide useful information about the health of transformers which will help the utilities to optimally use their transformers and keep transformer in operation for a longer period. This will also help identify problems before any sudden failure which can result in a significant cost savings and greater reliability. There are various fault occurred in transformer which causes damaged to the transformer if they are not diagnosed at quick time. It is thus important to monitor transformer continuously. Online monitoring is the solution for continuously observing the health of transformer. With the advancement in technology various technique are used for monitoring continuously the transformer. The global system for mobile communication (GSM) is the best among them. II.FAULTS IN TRANSFORMER 1) Overvoltage : When the voltage in a circuit or part of it is raised above its upper limit, this is known as overvoltage. The conditions may be hazardous. Depending on its duration, the overvoltage event can be transient a voltage spike or per manent, leading to a power surge . Electronic and electrical devices are designed to operate at a certain maximum supply voltage, and considerable damage can be caused by voltage that is higher than that for which the devices are rated.Due to this Overvoltage there may be Mal-operation of Circuit -Breaker or other accessories can be take place and hence Power system may get collapse.Thus monitoring of such faults becomes necessary . 2) Single phasing : Single phasing is an unwanted condition where one phase in a three-phase power system is missing, due to a tripped breaker or other condition. With just two lines hot, there is no phase rotation and thus the power delivered to the load is single-phase. This is very bad for most three-phase loads with reduced power and continuously drawing current. 3) Temperature : Hot spot of the winding is the maximum limit of the load capability. Previously the hot spot is calculated by knowing the measurement of oil temperature and of load of current. Abnormal temperature readings almost always indicate some type of failure in a transformer. For this reason, it has become common practice to monitor the hot spot, main tank, and bottom tank temperatures on the shell of a transformer. 4)Moisture :The presence of water in the oil can lead to reduction in the dielectric strength of transformer oil also ageing of oil is also affected .Thus all this can lead to electrical breakdown of transformer oil. This is very critical situation therefore continuous monitoring of operation is required to protect transformer from all of this. 5) Gas in Oil Analysis: The two principal causes of gas formation within an operating transformer are electrical disturbances and thermal decomposition especially in Oil. During the natural aging process of the oil and insulating parts, especially in the case of thermal or electrical failures, cracked gases form, and are dissolved in the oil. The rate of decomposition and the type of gases evolved during operation; result in thermal overloading and electrical faults. Thus analysis of gas in oil is important for protect the Transformer against such fault. Dissolved Gas Analysis is one method by which different gases can be finding out in transformer oil. The gases forms like Hydrogen (H2), Methane (CH4), Acetylene (C2H2), Ethylene (C2H4), and Ethane (C2H6). Further, when cellulose insulation is involved, thermal decomposition or electric faults produce Carbon monoxide (CO), and Carbon dioxide (CO2). Following table shows the various fault can be occurred because of gases formation in oil. [9] TABLE NO. 1 Different Types of Fault Occur Fault Type Gases Responsible Corona Hydrogen , Acetylene Insulator Effect Carbon Monoxide, Carbon Dioxide Arc Formation Acetylene and Hydrogen Sparking Methane and Ethane Overheating Methane and Ethylene Method of Dissolved Gas Analysis: Traditionally Dissolved Gas Analysis has been carried out by taking a sample of oil from the transformer, sending it to a laboratory and waiting for the results. Unless there was any suspicion of a problem in the transformer, samples might be taken at intervals of up to 1 year, depending on the maintenance report of the operator. This means that a fault that develops over a shorter period of time then the sampling interval can be missed, leading to possible catastrophic failure of the transformer . Manual sampling can also lead to errors in the analysis. Results can vary from laboratory to laboratory, and even between users of the same equipment Units. Now therefore it is important to monitor such DGA analysis online. Online monitoring not only automized system but also reduced the manual mistakes. Continuous online monitoring helps to keep record of transformer health at every instant .By monitoring and record key operation of transformer is not only thing to be considered but it is necessary .[ 12 ] 6) Vibration: Transformer vibration (and consequently noise) is caused by the magnetostriction of the core laminates (the extension and contraction of the core lamination. Under alternating fluxes, this extension and contraction takes place twice during a normal voltage or current cycle .This means that transformer is vibrating twice of the frequency of supply resulting in vibration to occur mainly at 120 Hz. This vibration level depends on the transformer construction and design. Vibration level shall increased by through fault current, phase to ground or phase to phase fault. Thus monitoring is necessary for any kind of vibration in the Transformer. III.GLOBAL SYSTEM FOR MOBILE COMMUNICATION Above fault identification techniques can be useful for identify various fault ,but it is always be helpful to have a continuous operation of transformer health because it causes least disturbance to the Transformer .Thus we proposed one method called as Global System for Mobile communication ( GSM ) helps to record operation of transformer and convey its data continuously to the operator by sending massage regarding transformer health .Previously SCADA system are used to monitor and record such key operation of transformer but since this system is complex and it is expensive to use .Thus GSM is the best alternative to it .Further the network of GSM technology is wider than other network hence it is flexible to use . [3] IV.DESCRIPTION OF METHODOLOGY The proposed on-line monitoring system consists of Global Service Mobile (GSM) Modem, with chip microcontroller and different sensor. It is installed at the transformer site and the finding parameters recorded using the analog to digital converter (ADC) of the embedded system. The acquired parameters are processed and recorded in the system memory. If there is any abnormality or an emergency situation the system sends SMS (Short Message Service) messages to designated mobile telephones containing information about the abnormality. Also, it sends SMS to a central database via the GSM modem for further processing. This mobile system will help the system to run under reliable condition and identify problems before any failure. V.BLOCK DIAGRAM The block diagram of proposed model is as follows. [11] VI . Ways of detecting various faults for online monitoring of Transformer 1) Measurement of Over-voltage : To measure overvoltage we used step down transformer in our project. The transformer connect across the phase and neutral of each phases (R, Y, B), which step down voltage from 300v AC (max) to 5 volt AC, further This voltage will be converted to DC by means of rectifier and give it to the input of ADC, the ADC will convert this signals in equivalent digital signals and give it to microcontroller. Further microcontroller compares these digital signals with the settled overvoltage (250v) and under voltage (180v) If the signals is greater than 250 volt and less than 180volt then the microcontroller trips the contactor. If in case of phase failure the microcontroller treat this fault as a under voltage because if any phase is not available that means the voltage is less than 180 v (0 volt is less than 180 volt) in this case also microcontroller trips the contactor. 2) Single Phasing : Single phasing can be prevented by using single phasing preventer. Single phasing preventer is an electronic circuit which prevents the three phase electronic operated electrical machines from single phase cut off, phase reversal and phase imbalance . 3) Temperature Monitoring: In order to make on-line monitoring possible, thermocouples are placed externally on the transformer and provide real-time data on the temperature at various locations on the transformer. High main tank temperatures have been known to indicate oil deterioration, insulation degradation, and water formation. 4) Moisture: Online monitoring can be used to improve the accuracy of Oil .Moisture sensors available can easily detect the presence of any moisture. 5) DGA Analysis: Nowadays DGA usually consists of three steps: i) Sampling of oil in an airtight glass tube made up of borosilicate of capacity 150 ml to 250 ml. ii) The DGA technique involves extracting or stripping the gases from the oil and injecting them into a gas chromatograph (GC). Detection of gas concentrations usually involves the use of a flame ionization detector (FID) and a thermal conductivity detector (TCD). Most systems also employ a methanizer, which converts any carbon monoxide And carbon dioxide present into methane so that it can be burned and detected on the FID, a very sensitive sensor. iii) The separated gases are detected by thermal conductivity detector for atmospheric gases, by flame ionization detector for hydrocarbons and oxides of carbon. Following fig no. 3 [13] shows the Gas Chromatography technique: FIG. NO 3 Thus at present, gas chromatography is the main method which can achieve the fault diagnosis by the on-line monitoring to the dissolved gases in the transformer oil. But it has many disadvantages, such as the aging, Pollution and saturation of chromatogram columns and it takes a long time consuming much carrier gases during the monitoring process. Concerning these disadvantages, on-line monitoring to the groups of dissolved gases through the gas sensor array is suggested. [7] VII. Conclusion Due to daily increased load of power system it is important to maintain system Reliability .As transformer plays important role in power system by maintaining reliability it is important that we should keep transformer from daily fault occurring in it just by observing its key parameter so that such fault cannot result in bigger failure also apart from these sharing of data information is also essential using new technology at reduced cost . System to expert systems can be used to achieve all the parameters test and analysis of automation every system is automated in order to face new challenges in the present day situation. Automated systems have less manual operations, so that the flexibility, reliabilities are high and accurate. Hence every field prefers automated control systems. Especially in the field of electronics automated systems are doing better performance. [10] VIII. References [1] Guiyin Yu, and Lu Zhang, Application of Electrical Transformer Online Monitoring System International Conference on Intelligent Control and Information Processing August 13-15, 2010 Dalian, China [2] Abdul-Rahman AI-Ali, Abdul Khaliq Muhammad Arshad, GSM-Based Distribution Transformer Monitoring System Dubrovnik, Croatia IEEE MELECON 2004, May 12-15, 2004 [3] Constantin Daniel Oancea, Member, IEEE GSM Infrastructure Used for Data Transmission The 7 th international symposium on advanced topicin electrical engineering, Bucarest May 11-14 2011 [4] Fagarasan, Sorina Costina, Sergiu St. ILIESCU3, Monitoring and Diagnosis Methods for High voltage power Transformer U.P.B. Sci. Bull., Series C, Vol. 70, No. 3, 2008 [5] Cbengtsson ABB Transformers AB Ludvh, Sweden,Status and Trends in Transformer MonitoringIEEE Transactions on Power Delivery, Vol.11, No. 3, July 1996 [6] J.C. Burgos , E. Pagan , B. Garcia , Experiences in Managing Transformers through Maintenance Operations and Monitoring Systems 21, rue dArtois, F-75008 Paris http://www.cigre.org,May 2004[7] Lynn Hamrick ESCO Energy Services,Dissolved Gas Analysis for Transformers Winter 2009-2010 NETA WORLD [8] A. Kingsmill S. Jones Application of new condition Monitoring Technologies in the Electricity Transmission Industry, Transgrid University of Australia [9] Fredi Jacob Dissolved Gas Analysis, Past Present Future ACTI Inc. Jan 21, 2003. [10] Brian D Sparling, Jacques Aubin,Power Transformer life extension through better monitoring [11] A review by Vidhata Technologies [12]Sherif S.M.Ghoneim,Advances in electrical Engineering sy stem , Volume 1 2012, ISSN 2167-633 [13] Online transformer monitor site preparation guide ,Model T M Series ,August 27 2008

Ethical Codes Essay

Over the years, there have been a lot of technological developments in the field of psychology. These developments have not left psychological assessment and testing behind as it has also been affected. However, there are a number of ethical issues that have been raised in this field concerning computerized assessment and testing. The main aim of these testing is to ensure that human beings have a better life in future. It is believed that this field has a very complicated technology and therefore very few graduates are there to operate and execute the commands that the computers in this field needs. This means that most of those people who are using computerized assessment and testing are armatures. Thus, there is poor interpretation of the results. The departments that are responsible for this are fully aware of this and they still allow these inexperienced people to conduct tests on human beings. This can be termed as ethically inappropriate. (Lewis, 2000) In addition, computers are machines and therefore they do not have any feelings. It is therefore obvious that while they are used in assessment and testing, they operate on some specific commands and thus, they will only give feedback based on those commands. Human beings are known to be unique and therefore there is a chance that they will not behave in the same way. Therefore, the computerized assessment and testing has also been cited as being dehumanizing as the machines operate under some specific commands. The ethical code that pertains to this type of testing and all the relations to assessment and testing is the code of fair testing and practices. There is no fair testing and practices as the practitioners who practice in this field are fully aware that they are not giving the best to their clients. (Lewis, 2000) As a practitioner, it is always advisable to give the best to the clients and at the same time to be fair in all the activities. I would therefore do more research and ensure that I am well conversant with all the practices that are involved in the computerized testing and assessment. Where possible, I would conduct more research to see to it that computerized testing and assessment is more client-friendly and it is not dehumanizing. ? References Lewis, A. (2000). Psychological Assessment & Testing. New York: Pearson Education.

`` The Yellow Wallpaper `` By Charlotte Perkins Gilman

â€Å"John laughs at me, but one expects that in marriage.† Charlotte Perkins Gilman wrote, â€Å"John laughs at me, of course, but one expects that in marriage.† In her The Yellow Wallpaper men attempted to prevent women from achieving their intellectual and creative potential by making women be their subordinates. The dreadful wallpaper that Gilman came to hate in her story is a symbolic representation of her personal life were as she gets married her role is limited to that of a domestic servant as her husband exercises authority over her. For example, in some parts of the world today, some women under the institution of marriage are still caged because they must accept control or instructions from men as a social expectation. Gilman and Chopin in their short stories how the male dominated society used power to imprison, oppresses, silences, and encourages submissiveness among married women. The freedom for a woman to speak, think, act and contribute to decision making in her marriage contributes to the fight for equality between m en and women. The short story The Yellow Wallpaper by Charlotte Perkins Gilman illustrates the struggle faced by women who seek freedom from oppression. Gilman reveals in this short story how the narrator feels oppressed by her husband despite her love for writing by stating, â€Å"He hates to have me write a word† (218). This narrator is apparently feeling trapped in a marriage that does not allow her freedom to do the thing she enjoys. The trapped womanShow MoreRelatedThe Yellow Wallpaper By Charlotte Perkins Gilman885 Words   |  4 Pagesbeen a stigma around mental illness and feminism. â€Å"The Yellow Wallpaper† was written by Charlotte Perkins Gilman in the 1900’s. â€Å"The Yellow Wallpaper† has many hidden truths within the story. The story was an embellished version her own struggle with what was most likely post-partum depression. As the story progresses, one can see that she is not receiving proper treatment for her depression and thus it is getting worse. Gilman uses the wallpaper and what she sees in it to symbolize her desire to escapeRead MoreThe Yellow Wallpaper By Charlotte Perkins Gilman846 Words   |  4 PagesHumans are flawed individuals. Although flaws can be bad, people learn and grow from the mistakes made. Charlotte Perkins Gilman’s short story, â€Å"The Yellow Wallpaper†, gives one a true look at using flaws to help one grow. Gilman gives her reader’s a glimpse into what her life would have consisted of for a period of time in her life. Women were of little importance other than to clean the house and to reproduce. This story intertwines the reality of what the lives of woman who were considered toRead MoreThe Yellow Wallpaper By Charlotte Perkins Gilman1362 Words   |  6 Pagesas freaks. In the short story â€Å"The Yellow Wallpaper† by Charlotte Perkins Gilman, both of these elements are present. Gilman did a wonderful job portraying how women are not taken seriously and how lightly men tal illnesses are taken. Gilman had, too, had firsthand experience with the physician in the story. Charlotte Perkins Gilman s believes that there really was no difference in means of way of thinking between men or women is strongly. â€Å"The Yellow Wallpaper† is a short story about a woman whoRead MoreThe Yellow Wallpaper By Charlotte Perkins Gilman1547 Words   |  7 PagesCharlotte Perkins Gilman s career as a leading feminists and social activist translated into her writing as did her personal life. Gilman s treatment for her severe depression and feelings of confinement in her marriage were paralleled by the narrator in her shorty story, The Yellow Wallpaper. Charlotte Perkins Gilman was born in 1860 in Hartford, Connecticut. Her parents, Mary Fitch Perkins and Fredrick Beecher Perkins, divorced in 1869. Her dad, a distinguished librarian and magazine editorRead MoreThe Yellow Wallpaper By Charlotte Perkins Gilman2032 Words   |  9 Pagesâ€Å"The Yellow Wallpaper† by Charlotte Perkins Gilman is a poem about women facing unequal marriages, and women not being able to express themselves the way they want too. Charlotte Perkins Gilman was born in 1860, and died in 1935. This poem was written in 1892. When writing this poem, women really had no rights, they were like men’s property. So writing â€Å"The Yellow Wallpaper† during this time era, was quite shocking and altered society at the time. (Charlotte Perkins Gilman and the Feminization ofRead MoreThe Yellow Wallpaper By Charlotte Perkins Gilman904 Words   |  4 Pagescom/us/definiton/americaneglish/rest-cure?q=rest+cure). Charlotte Perkins Gilman wrote The Yellow Wallpaper as a reflection of series of events that happened in her own life. Women who fought the urge to be the typical stereotype were seen as having mental instabilities and were considered disobedient. The societal need for women to conform to the standards in the 1800s were very high. They were to cook, clean and teach their daughters how to take care of the men. Gilman grew up without her father and she vowedRead MoreThe Yellow Wallpaper By Charlotte Perkins Gilman999 Words   |  4 Pages â€Å"The Yellow Wallpaper† is a story of a woman s psychological breakdown, which is shown through an imaginative conversation with the wallpaper. The relationship between the female narrator and the wallpaper reveals the inner condition of the narrator and also symbolically shows how women are oppressed in society. The story, read through a feminist lens, reflects a woman s struggle against the patriarchal power structure. In the â€Å"The Yellow Wallpaper†, Charlotte Perkins Gilman uses the wallpaperRead MoreThe Yellow Wallpaper By Charlotte Perkins Gilman Essay1208 Words   |  5 Pagesthat wallpaper as I did?† the woman behind the pattern was an image of herself. She has been the one â€Å"stooping and creeping.† The Yellow Wallpaper was written by Charlotte Perkins Gilman. In the story, three characters are introduced, Jane (the narrator), John, and Jennie. The Yellow Wallpaper is an ironic story that takes us inside the mind and emotions of a woma n suffering a slow mental breakdown. The narrator begins to think that another woman is creeping around the room behind the wallpaper, attemptingRead MoreThe Yellow Wallpaper By Charlotte Perkins Gilman846 Words   |  4 PagesThe dignified journey of the admirable story â€Å"The Yellow Wallpaper† created by Charlotte Perkins Gilman’s, gave the thought whether or not the outcome was influenced by female oppression and feminism. Female oppression and feminist encouraged a series of women to have the freedom to oppose for their equal rights. Signified events in the story â€Å"The Yellow Wallpaper† resulted of inequality justice for women. Charlotte Perkins Gilman gave the reader different literary analysis to join the unjustifiableRead MoreThe Yellow Wallpaper By Charlotte Perkins Gilman1704 Words   |  7 PagesEscaping The Yellow Wallpaper Charlotte Perkins Gilman (1860-1935) whom is most acclaimed for her short story The Yellow Wallpaper (1891) was a women’s author that was relatively revolutionary. Gilman makes an appalling picture of captivity and confinement in the short story, outlining a semi-personal photo of a young lady experiencing the rest cure treatment by her spouse, whom in addition to being her husband was also her therapist. Gilman misused the rest cure in The Yellow Wallpaper to alarm other

Islamic Banking Systems and Their Characteristics Directed by the Shariah Free Essay Example, 7250 words

In order to understand the theoretical background of Islamic banking, it is first necessary to define Islamic banking. To this end, Aburime and Alio (2009: 321) define Islamic banking as A system of banking or banking activity that is consistent with Islamic law Shariah principles and guided by Islamic economics. Broadly, Islamic law Shariah principles govern the daily lives and activities of Muslims and this includes financial transactions (Anas Mounira, 2009: 124). Under Islamic law Shariah principles, all behaviour and business or financial transactions must be conducted in accordance with what is fair to all parties involved and must be consistent with ethical and religious conduct as prescribed by the Qur an and Sunnah (teachings of Muhammad) (Ainley et al, 2007: 4). Informed by the Qur an and Sunnah, Islamic banks generally commit to a prohibition against interest also known as riba (Nejatullah, 2004: 36). It has been theorized that a lot of the problems such as inflation and unemployment, associated with capitalism are connected to the practice of lending on interest (Nejatallah, 2006: 4). Islamic banking theory, therefore, dictates that Islamic banks share profit and loss with its depositors and include an element of mutuality (Jaffar Manarvi, 2011: 61). We will write a custom essay sample on Islamic Banking Systems and Their Characteristics Directed by the Shariah or any topic specifically for you Only $17.96 $11.86/page With safety/risk management as a significant rationale for banking regulation, there are two relevant theories applicable to banking regulation: positive and normative.