Modelling Of 3 Phase Transmission Line Engineering Essay

Modelling Of 3 Phase Transmission Line Engineering Essay Transmission line is a medium to transmit electric energy from one place to another for long distances with the aim is to reduce and economically. Voltage, current, power and power factor are the main point must be considered at the sending end and receiving end. Typically, in Malaysia the overhead transmission line was used because cost and maintenance can be handle easily. As we know, the transmission line produced high strength of electric and magnetic field under the tower. Based on that, this project will modeling transmission line using Finite Element Method (FEM) focus on level voltage 275kV. The result of simulation of the transmission line model will analyze electric and magnetic field under transmission line tower. 2.0 Problem statement It is well known understand that the Transmission Line for 275kV produced high strength of electric and magnetic field under the tower. In other word, the field strength of electric field may create higher stress to the tower that may also tend to create high risk to the tower as well as to the insulator to be used. Another issue is how much tendency of magnetic field to be effect to the human and environment has be identified wisely. However, the real measurement under 275kV transmission line tower may give high risk. Therefore, the best idea is to carry out the information as mention above is by performing simulation study. 3.0 Objective To collect the 275kV Transmission Line specification. To model the 275kV Transmission Line using Finite Element Method (FEM) To simulate the 275kV Transmission Line using Finite Element Method (FEM) To analyze the electric magnetic field generated by the 275kV Transmission Line model 4.0 Scope The scope of this project are :- Specification is based on TenagaNasionalBerhad (TNB) 275kV Transmission Line. Transmission Line modelling using Finite Element Method (FEM) software. 5.0 Literature survey and project background AnÂÂ  electric power systemÂÂ  is a network of electrical components used to supply, transmit and use electric power. The main parts of electric power system areÂÂ  generation, transmission system, distribution system and load. At generation part, to generate an electrical energy on large scale, energy must be generate from the various sources energy such as oil, natural gas and other. Then, the transmission system transmit or carries current that generate from generation and distribution system feeds electric to load such as consumer and industry. This project will discuss further about transmission line system.[1] 5.1 Transmission Line Transmission line or power line are important part in power network. Other than that, based on theory, transmission line also can be describe as propagation of electric waves along the transmission line. There are many factor must consider to design transmission line. Such as transmission voltage level, types of tower, environment and others. The transmission line also can be constructed in two ways, overhead transmission line and underground transmission line. 5.1.1 Underground Transmission Line In underground system, the cable must be selective because all conductor must be insulated in this system. Therefore, the voltage level for this system will below 66kV cause difficult to find insulation for high voltage. Underground transmission line usually use at crowded areas because the cable used preferred compare with overhead use bare conductor not suitable at that areas.[1] 5.1.2 Overhead Transmission Line Overhead transmission line usually use for transmit electric for over long distances. In this system, spacing between the tower and the conductor are very important cause to avoid an electric discharge between the conductors. The appropriate spacing between the conductor will produce insulation between them. This system also expose to fault such as short circuit, breakage of line and lightening. But it easy to troubleshoot and repair compare to underground transmission line. However, it difficult to find exact point of fault cause transmission line are very long. Other than that, between the tower and the conductor must have insulation to make the transmission more safety when do it maintenance. [1] 5.2 Types of Transmission Line Transmission line be separated two part AC transmission line voltage and High Voltage DC transmission line (HVDC). 5.2.1 High Voltage DC Transmission Line The main factor affecting the cost of energy increases is the process of transmission lines to transmit the power to the load away from power generation. To overcome this issue that is usually done AC transmission line is using HVDC transmission line. The HVDC transmission line requires conversion at two ends, from AC to DC at the sending end and back to AC at the receiving end. The converter are static using high power thyristors connected in series to give the required voltage ratings. The physical process of conversion is such that the same station can switch from rectifier to inverter by simple control action, thus facilitating power reversal.[2] Figure 5.2.1: Variation of costs with line length[4] Figure above show the variation of costs of transmission line with distance for AC and DC transmission. Based on figure, before break even distance, cost of AC transmission is reasonable and economical than DC transmission. Before the break even distance point, the distance is around 500 to 800 km, so after that point or longer distance HVDC transmission line more economical than AC transmission.[2] 5.2.2 AC Transmission Line Transmission line also can be classified into three types such as short transmission line, medium transmission line and long transmission line. For short transmission a length less than 80km, medium transmission between 80km until 240km and long transmission have length more 240km.[] Normally, the power grids also have three level of voltage; High voltage (HV), medium voltage (MV) and low voltage (LV). In Malaysia, based on fact from Tenaga Nasional Berhad (TNB), AC transmission line have standard voltage called National Grid. Below are standard voltage of AC transmission line:- i) 132kV ii) 275kV iii) 500kV 5.3 Modelling Transmission Line For this project focus on 275kV transmission line modelling. Before go through below some journal refer to this project. Based on journal titled Modelling and Analysing of a 275kV HVAC Transmission Line for Power System Transient Studies written by M. Z. A. Ab Kadir and C. Y Jay. In this journal, it discuss the efficiency and power losses of transmission line via the concept of travelling wave. This case study had be done at Kampung Awah- Paka, Terengganu. This paper was model transmission line using PSCAD/EMTDC software which they want analyze the efficiency between the frequency dependent model and PI-section model. Before design or model transmission line on simulation, this paper had consider three important parameter such as series resistance, series inductance and shunt capacitor. Based on tower information below, this paper obtained the parameter such as resistance, inductance and capacitance via calculation. From the information are given, Tenaga Nasional Berhad (TNB) such as Table 1, design PI-section model. Line name KAWA-PAKA Tower type System Voltage Frequency Line length Conductor diameter Bundle spacing Ground to conductor height Horizontal spacing Vertical spacing Double circuit lattice Three phase 275kV 50Hz 160km 24.16mm 400mm 12630 7300mm 13000mm Table 5.3: Parameter of 275kV KAWA-PAKA lattice tower[1] After consider all parameter, this paper construct design PI-section model using PSCAD/EMTDC software for 160km an overhead transmission line. To model 160km an overhead transmission line, this paper used eight identical pi-sections are connected series which each PI-section represent 20km of transmission line. By terminating the surge impedance at the end of transmission line, the efficiency can be measure. Figure 5.3.1: Line surge impedance using PI-section model [1] For the frequency dependent model, this project used it as a reference cause it is the most accurate model. From this model also, we can learn the transient or harmonic behaviour of a line. Figure 2 show frequency dependent model. Figure 5.3.2 : Line surge impedance using frequency dependent model[1] Both model are carried out using three different test such as, short circuit test, open circuit test and line surge impedance test. Line surge impedance test is a real line with minimum losses and both other are used to demonstrate the behaviour of the travelling wave. Section Model % differences Pi-section Freq. Dependent Pi-section Freq. Dependent 1 2 3 4 5 6 7 8 273.59 272.72 271.87 271.04 270.24 269.69 268.69 267.95 272.97 271.28 269.32 267.10 264.63 263.55 263.01 262.22 0.33 0.65 0.96 1.26 1.55 1.84 2.11 2.38 0.56 1.17 1.88 2.69 3.59 3.98 4.18 4.47 Table 5.4 : Summary of Pi-section and Frequency dependent model Result of output voltage of each 20km section are summarized in Table above. From the Table, result of this project show the output voltage of Pi-section model and Frequency Dependent model are approximately same. In the real transmission line system, we expect voltage level before step up or step down at substation are maintain. Based on Table above, compare the output voltage of the Frequency dependent low than Pi section because the frequency dependent model consider all losses such as hysteresis, corona effect, eddy current losses in nearby ferromagnetic materials and induced losses in nearby short circuited non ferromagnetic material while Pi-section model only consider proximity effect and skin effect. Conclude from that, the efficiency both model are acceptable and approximately same. An efficiency percentage for Pi-section model is 97.6% and Frequency dependent model 95.5%. This project successful in modelled Pi-section model using PSCAD/EDMTC software and analyzed by compare with Frequency dependent model.[3] Second journal titled Power Flow Assesment in Transmission Lines using Simulink Model with UPFC written by Ch. Chengajah and R. V. S.Satyanarayana. This paper discuss about the performance of a single and double transmission line system (6.6/22)kV using UPFC or without UPFC model. UPFC is a Unified Power Flow Controller which it can improve capability of power transfer or in other word to provide comprehensive control of power flow in transmission system.[4] This paper model the transmission line using Simulink to connected with UPFC model. Figure below show the transmission line model with UPFC device by using Simulink. From the figure show the double circuit 22kV and 6.6kV interconnected with UPFC model. UPFC device function to control voltage profile as the real and reactive power in the transmission line.[4] Figure5.3.2: Transmission line model with UPFC device[4] Table below show the result of power flow and voltage profile transmission line model with UPFC and without UPFC. Parameter 6.6kV Line 22kV Line Without UPFC With UPFC Without UPFC With UPFC Voltage magnitude(kV) 2.926 2.961 9.754 5.162 Real Power(MW) 0.274 0.281 3.050 0.854 Reactive Power(Mvar) 0.205 0.210 2.280 0.639 Table 5.5: Result power flow and voltage profile[4] Based on table above, this paper compare three parameter such as voltage magnitude, real power and reactive power. From that, an improvement can see for both transmission line when interconnect with UPFC. From that, this paper suggest improvement in transmission line system.[4] 5.5 Summary Based on both journal discussed different step to model transmission line. For first journal, using PSCAD software, the paper make comparison efficiency between PI-section model and Frequency Dependent model. The paper construct by consider parameter such as resistance, inductance and capacitor to model transmission line. Then, PI-section model had been construct which each PI-model represent 20km. The simulation had be done not like real transmission line system but result at end of experiment approximately same. Figure 5.3.1: Line surge impedance using PI-section model [3] For second journal, it use MATLAB/SIMULINK software to model transmission line. This paper discuss about function Unified Power Flow Controller (UPFC) in transmission system to improve voltage and power profile. This paper also consider value parameter such as resistance, inductance and capacitor to construct the model. Figure 5.5 22kV Transmission Line Simulink Model[2] Figure 5.5 above show example 22kV transmission line simulink model. At this end of this paper show result comparison between transmission line system with and without Unified Power Flow Controller (UPFC). Therefore, this project propose to use Finite Element Method(FEM) to model transmission line. This project will model transmission line like a real transmission line using specification Tenaga Nasional Berhad (TNB). This project focus on 275kV HVAC transmission line and will model like real tower for 275kV transmission line. Besides that, significant of this project also can see electric and magnetic field at transmission line. From that, this project analyze further about effect electric field and magnetic field to human and environment. 6.0 Methodology Start Collect the 275kV Transmission Line specification. Model the 275kV Transmission Line using Finite Element Method (FEM) Troubleshooting simulation Simulate the 275kV Transmission Line using Finite Element Method (FEM) Results Electric field and magnetic field Analyze the electric magnetic field generated by the 275kV Transmission Line model End Figure 6.0: Flow chart of Final Year Project 6.1 Collect the 275kV Transmission Line specification. In this process, the specification of data of 275kV tower in Malaysia is needed to be collect from TNB (Tenaga Nasional Berhad). The data that need to be collect is the tower height from ground level, the distance between phase to ground, the distance between phase to phase, and distance between ground wire to phase. Other than that, types and size conductor that used for 275kV also need to collect. 6.2 Model the 275kV Transmission Line using Finite Element Method (FEM) Based on data collection, model transmission lines tower with the conductor such as specification that used by TNB using Finite Element Method (FEM). 6.3 Simulate the 275kV Transmission Line using Finite Element Method (FEM). For this step, simulate the model transmission line 275kV that construct before using Finite Element Method (FEM). 6.4 Results Electric field and magnetic field The expected result are to modelling transmission lines using new method using FEM. Other than that, this project also expected to produce electric field and magnetic field at transmission lines from one point to next point. 6.5 Analyze the electric magnetic field generated by the 275kV Transmission Line Analyze the electric magnetic field around transmission line 275kV model based on display from simulation. 7.0 Expected Results/Benefit The result of this project should be able to design transmission line model using Finite Element Method (FEM) where the model must satisfied 275kV transmission line specification from Tenaga Nasional Berhad (TNB). The model are include electric field and magnetic field. From that, analyze the result based on electric field and magnetic field around the transmission line model. This project will develop new method and new software to model transmission line with electric field and magnetic field by using Finite Element Method (FEM) from ANSYS Maxwell. 8.0 Milestones Task Date expectation Complete literature review on the design of Three Phase Transmission Line including the characteristic needed in design modeling. Nov 2012 Complete search and collect data of 275kV transmission line Jan 2013 Complete analyze the function of Finite Element Method to calculate the magnetic field and electric field. March 2013 Complete design optimization April 2013 Complete testing model with different parameter and analyze May 2013 Final report writing (including paper/journal writing) and presentation June 2013

Computer Information Systems Brief Essay

In order for the company to continue to thrive, consideration of growth opportunities will also be analyzed. In addition, the threats that Kudler may encounter if changes are not implemented will also be discussed throughout this evaluation. The owner of Kudler Fine Food stores offer gourmet foods and fine wines all within one location. All store locations offer baked goods, meat, seafood, produce, cheese, dairy products, and wine with little or no preservatives added. The success of Kudler Fine Foods is in part from the systems that the stores have in place. For example, the current computer system is available 24 hours a day, seven days a week, the owner provides training to all employees and is, therefore, understood by all employees. This understanding of the computer system enables the daily operations of the business to thrive as sales increase. As the company moves forward and introduces changes with technological advances, continued employee training is a must with the installation of new hardware and software programs. The number of products that must be accounted for, on a daily basis, at the Kudler locations is extensive. Presently, Kudler’s accounting data is collected by point-of-sale (POS) terminals in each store. The terminals are used as cash registers when customers check-out. The POS system records all sales, items, quantities, prices, taxes and totals for all transactions. â€Å"These intelligent terminals use keypads, touch screens, bar code scanners, and other input methods to capture data and interact with end users during a transaction, while relying on servers or other computers in the network for further transaction processing† (O’Brien & Marakas, 2008, p. 81). Furthermore, functions are available for various types of sales reports to be created with the current system. However, the current system does not meet the needs of the business as the computer system is outdated. Furthermore, the founder of the company, Kathy Kudler, is having great difficulty with monitoring the needs of the three stores and the situation will soon become overwhelming with further expansion. Ms. Kudler needs a computer system that will accommodate her current and future needs for her growing gourmet food business. Currently, each of locations operates with a stand-alone POS system. Ms. Kudler must travel between stores to ensure the managers are meeting her high standards and creates a substantial loss in productivity. The lack of remote access also presents an issue for the future expansion plans for the business. With no way to access accounting, inventory, and sales information, successful expansion will not be possible. Ms. Kudler’s presence is a daily requirement at each location to manage the operations, inventory, sales, etc. and without updated computer technology the company cannot see any further growth. Not only is the company facing limited expansion possibilities, but current security measures are not sufficient. Although Kudler’s present system is password protected and has backup capability, financial information may be in jeopardy. With the implementation of a new system can easily remedy this situation giving added security to the company. In addition to the company’s financial information, protection to the company’s customer base should also be of great concern. In particular, the customer’s credit card information is at high risk. Additional security measures addressing such concerns as passwords, employee identification numbers, and restricting employee personal use must be applied. For example, a proxy server can limit the employee’s internet access to approved websites (Bargranoff, Simkin, & Strand, 2008). Not only will a proxy server prevent counterproductive activity from employees, but it will also limit the exposure to threats from viruses, theft, and internet hackers. There are both strengths and weaknesses with Kudler’s Fine Foods current computer technology practices. Kudler Fine Foods uses the POS system to record sales, items, quantities, prices, taxes and totals for all transactions. However a continuous challenge Ms. Kudler faces is the purchasing of additional inventory. The company uses forecasting, which allows the company to replenish its inventory based upon historical sales information. For the company to monitor its supply, a system must be implemented that will track individual items and allow managers to re-order necessary inventory from this information. The issue with a forecasting inventory system is that the decisions are based upon past performance, 2 to 3 years old. Unfortunately, sales do not follow the same pattern from year to year. In addition, sales from holidays, birthdays, weddings, and the like are not accounted for under the forecasting system. Every year orders will continue to change depending on the economic stability of the state. Furthermore, holidays will not always be on the same day and will subsequently affect the forecasting information. In the event that too much inventory is order, the excess is donated to charity if in good condition, if not the excess is thrown away. Inventory management is crucial due to the perishing potential of the inventory items. It is a delicate balance because to satisfy customers, there must be enough on hand merchandise to avoid sales losses. It is imperative that Kudler Fine Foods increase the use of technology, if the company is to continue to grow and thrive. Most importantly that is a definite need for a network to assist Ms. Kudler with her communication needs between her stores and add updated software to handle the company’s inventory needs. To implement the new technology, funding and training will be required. The procurement of new software will be required for Ms. Kudler and her employees to run effectively and efficiently.

Business School

Reading Analysis of the First Six Lessons by Richard Boleslavsky Free Essay Example, 1500 words

The actors must have a sharp memory to enable them to grasp and to have confidence when on stage. The chapter outlines the concept of memory and emotion by giving examples through questioning, acting and role play (Boleslavsky15-34). My reflection on this chapter is that it grasps some of the factors that actors need to consider before entering the stage and when formulating their plays. I understand the role of sharp memory in helping actors to gain confidence when performing. Similarly, actors must make their plays have memorable moments, which audiences can remember. This will act as the selling point of the play, hence making it pleasing. Moreover, the concept of emotion is very important because it makes audiences identify with the play. An emotional play will attract concentrations of audiences and make them stay focused towards the play. Hence, I believe the chapter has put the important point, which actors must consider to gain confidence in the stage. The chapter talks abou t dramatic actions that drive a play. The author acknowledges the role of dramatic actions as one of the features in a play that makes people pay attention hence very important. We will write a custom essay sample on Reading Analysis of the First Six Lessons by Richard Boleslavsky or any topic specifically for you Only $17.96 $11.86/pageorder now Similarly, the chapter elaborates how different actors within a play can achieve a dramatic action to bring the entertaining part of the play. The chapter is very clear in outlining different stages, which actors can use to arrive at the dramatic action, which is always the climax of any play. Throughout the chapter, the author has used and questioned on the use of dramatic actions that is very vital for the understanding of ways of achieving the same (Boleslavsky 36-50). I feel the chapter is very important for anyone who wants to make it higher in the play. It gives the readers the in-depth understanding of ways of achieving dramatic actions since it is the core of any play. Therefore, I am challenged on what I should be doing to make me achieve dramatic actions, which will keep my audience moving. The chapter on the dramatic action is also vital to anyone to understand the concepts to employ when he or she wants to achieve the desired goals of ma king the audience enjoy a play or an action. I believe putting these concepts into practice will be vital to the realization of entertainment goal.