Topic outline

  • EEE 441 : Transmission and Distribution of Electrical Power

    This course (Transmission and Distribution of Electrical Power) will let the students to study power supply system, practical grounding in wide range of transmission and distribution areas. This course will help the student to receive clear and unambiguous transmission and distribution equipment or project related inquiries for working in practical field and enhance the technical skill. This course should help the students to understand the reasoning behind the different specifications and methods used by different electrical supply utilities and organizations throughout the world to achieve their specific transmission and distribution power system requirements.

    Instructions:

    • All course materials can be found here.
    • Any announcement regarding the class/assessments/notification will be posted on "Announcements" section.
    • The Assignments, Quizzes/CT and Presentation will be held online through DIU-BLC.
    • The question patterns and the syllabus for the quizzes, midterm and final exam are given in each section separately.
    • There are Midterm and Final exam preparation Forum under these sections where students can discuss with each other about their Midterm and Final exam syllabus, any problem regarding the exam etc.
    • Students can provide their valuable feedback under each of the Lecture Module through 'Discussion Forum' and bonus marks will be awarded accordingly

  • Course Instructor(s)

              Name:     Sudipta Sarker 

              Designation: Lecturer 
              Room: No  .805 
               Permanent Campus, Ashulia Dhaka 
               Mobile no:01536203989
               mail:sudipta.eee0185.c@diu.edu.bd
               mail: (personal) Sudiptasarker.ss@gmail.com
               

             

  • Course Information

    The objectives of this course are:

    • To give the students requisite basic knowledge about key parameters of transmission and distribution of modern power supply system
    • To introduce different problems related to power transmission and distribution and discussing their solutions
    • To develop ability so that students can design and solve problems that arise in transmission and distribution systems


    Course Outcomes (COs) and Mapping with Program Outcome (POs):

    Learning Outcomes:

    Getting theoretical concepts related to power system transmission and distribution

    Course Contents:

      • Current and voltage relation on a transmission line.
      • Representation of line: short, medium and long transmission line, tee and pi representation, exact solution.
      • Generalized line constant: general line equation in terms of A, B, C, D constants, relations between constants.
      • Mechanical characteristics of transmission line: sag and stress analysis, wind and ice loading, supports at different elevations.
      • Insulators for overhead lines: types of insulators, their constructions and performance, potential distribution in a string of insulators, string efficiency. methods of equalizing potential distribution; special types of insulators, testing of insulators.
      • Voltage and power factor control in transmission systems: Tap changing transformers, on load tap changing, Inductance regulators, Moving coil regulators, boosting transformers, Power factor control, static condensers, synchronous condenser.

    • Module 01: Introduction to Electric Supply System

      Introduction:

      In early days, there was a little demand for electrical energy so that small power stations were built to supply lighting and heating loads. However, the widespread use of electrical energy by modern civilization has necessitated to produce bulk electrical energy economically and efficiently. The increased demand of electrical energy can be met by building big power stations at favorable places where fuel (coal or gas) or water energy is available in abundance. This has shifted the site of power stations to places quite away from the consumers. The electrical energy produced at the power stations has to be supplied to the consumers. There is a large network of conductors between the power station and the consumers. This network can be broadly divided into two parts ie., Transmission and Distribution.

      Learning Objectives:

      • To familiarize with the power supply system
      • To understand the importance of Transmission and Distribution of Electrical Power in Electrical & Electronic Engineering
      • To know how electrical power is being delivered from generation point to consumer end

      Lecture Contents:

      • Introduction to the Course
      • A brief discussion on weight division, assessment strategy, learning activities and other particulars related to the course
      • Electric Power Supply System
      • Typical AC Power Supply Scheme
      • Comparison of DC and AC Transmission
      • Advantages of High Transmission Voltage
      • Various Systems of Power Transmission
      • Requirements of Satisfactory Electric Power Supply

      Learning Outcomes:

      The students will be able to
      • Learn the basic concepts of Power Supply Systems
      • Know how the power is transferred to consumers
      • Differentiate AC/DC transmission
      • Understand the relying factors on satisfactory power supply

      • Module 02 : Overhead Transmission Lines and Its Performance

        Introduction:

        The important considerations in the design and operation of a transmission line are the determination of voltage drop, line losses and efficiency of transmission. These values are greatly influenced by the line constants R, L and C of the transmission line. For instance, the voltage drop in the line depends upon the values of above three line constants. Similarly, the resistance of transmission line conductors is the most important cause of power loss in the line and determines the transmission efficiency.


        Learning Objectives:

        • To understand basics of transmission line
        • To know about the constants of transmission line
        • To design and interpret the performance of transmission line

        Lecture Contents:

          • Constants of Transmission Lines
          • Skin Effect
          • Classification of Overhead Transmission Lines
          • Performance of Single Phase Short Transmission Lines
          • Three-Phase Short Transmission Lines
          • Effect of Load p.f. on Regulation and Efficiency
          • Medium Transmission Lines and solution methods
          • End Condenser Method to solve Medium transmission line


          Learning Outcomes:

          The students will be able to
          • develop formulas by which we can calculate voltage regulation, line losses and efficiency of transmission lines
          • understand the effects of the parameters of the line on bus voltages and the flow of power
          • realize overall understanding of what is occurring on electric power system
          • apply different methods for solving short, medium and long transmission lines

          • Module 03: Transmission Lines - T/Pi method, ABCD Constants

            Introduction:

            The capacitance is uniformly distributed over the entire length of the line. However, in order to make the calculations simple, the line capacitance is assumed to be lumped or concentrated in the form of capacitors shunted across the line at one or more points. Such a treatment of localizing the line capacitance gives reasonably accurate results. The most commonly used methods (known as localised capacitance methods) for the solution of medium transmissions lines are : (i) End condenser method (ii) Nominal T method (iii) Nominal π method.
            It is well known that line constants of the transmission line are uniformly distributed over the entire length of the line. However, reasonable accuracy can be obtained in line calculations for short and medium lines by considering these constants as lumped. If such an assumption of lumped constants is applied to long transmission lines (having length excess of about 150 km), it is found that serious errors are introduced in the performance calculations. Therefore, in order to obtain fair degree of accuracy in the performance calculations of long lines, the line constants are considered as uniformly distributed throughout the length of the line. Rigorous mathematical treatment is required for the solution of such lines.
            In any four terminal network, the input voltage and input current can be expressed in terms of output voltage and output current. Incidentally, a transmission line is a 4-terminal network; two input terminals where power enters the network and two output terminals where power leaves the network. Therefore, the input voltage (VS) and input current (IS) of a 3-phase transmission line can be expressed as :
            Vs = A VR + B IR and IS = C VR + D IR
            here A, B, C and D (generally complex numbers) are the constants known as generalized circuit constants of the transmission line. The values of these constants depend upon the particular method adopted for solving a transmission line. Once the values of these constants are known, performance calculations of the line can be easily worked out.

            Learning Objectives:

            • To identify and differentiate different types of transmission lines
            • To know mathematical modeling of medium transmission lines and different methods
            • To familiarize with different methods of solving transmission line performance
            • To understand and determine generalized circuit constants of transmission line

            Lecture Contents:

            • Medium Transmission Lines and solution methods
            • Nominal T Method
            • Nominal π Method
            • Long Transmission Lines
            • Analysis of Long Transmission Line (Rigorous method)
            • Generalized Circuit Constants of a Transmission Line
            • Determination of Generalized Constants for Transmission Lines

            Learning Outcomes:

            The students will be able to
            • classify different types of transmission lines
            • formulate and apply different methods of solving and calculating transmission line performance
            • understand generalized circuit constants and determine their quantity

          • Module 04 : Mechanical Design of Overhead Transmission Lines - Conductors/ Line Supports / Insulators

            Introduction:

            Electric power can be transmitted or disributed either by means of underground cables or by overhead lines. The underground cables are rarely used for power transmission due to two main reasons. Firstly, power is generally transmitted over long distances to load centres. Obviously, the installation costs for underground transmission will be very heavy. Secondly, electric power has to be transmitted at
            high voltages for economic reasons. It is very difficult to provide proper insulation† to the cables to withstand such higher pressures. Therefore, as a rule, power transmission over long distances is carried out by using overhead lines. With the growth in power demand and consequent rise in voltage levels, power transmission by overhead lines has assumed considerable importance.

            Learning Objectives:

            • To gather knowledge about line insulators and their performance characteristics
            • To know how to erect transmission and distribution lines, requirement criteria

            Lecture Contents:

            • Insulators
            • Types of Insulators
            • Potential Distribution over Suspension Insulator String
            • String Efficiency
            • Methods of Improving String Efficiency 

            Learning Outcomes:

            The students will be able to 
            • Get ideas about insulators and their applications
            • Apply the methods of equalizing potential distribution; special types of insulators, testing of insulators

            • Module 05 : Mechanical Design of Overhead Transmission Lines - Sag

              Introduction:

              While erecting an overhead line, it is very important that conductors are under safe tension. If the conductors are too much stretched between supports in a bid to save conductor material, the stress in the conductor may reach unsafe value and in certain cases the conductor may break due to excessive tension. In order to permit safe tension in the conductors, they are not fully stretched but are allowed to have a dip or sag.


              Learning Objectives:

              • To understand sag and its importance
              • To realize how to design overhead lines by maintaining sag

              Lecture Contents:

              • Sag in Overhead Lines
              • Calculation of Sag (i) Supports are at equal levels and (ii) Supports are at unequal levels
              • Effect of wind and ice loading
              • Some Mechanical Principles

              Learning Outcomes:

              The students will be able to 
              • Design overhead lines by managing sag, tension and ground clearance
              • Understand mechanical factors of safety to be used in transmission line design

              • Course Assessments

                • Module 08 : Voltage Control

                  Introduction:

                  In a modern power system, electrical energy from the generating station is delivered to the ultimate consumers through a network of transmission and distribution. For satisfactory operation of motors, lamps and other loads, it is desirable that consumers are supplied with substantially constant voltage. Too wide variations of voltage may cause erratic operation or even malfunctioning of consumers’ appliances. To safeguard the interest of the consumers, the government has enacted a law in this regard. The statutory limit of voltage variation is ± 6% of declared voltage at consumers’ terminals. The principal cause of voltage variation at consumer’s premises is the change in load on the supply system. When the load on the system increases, the voltage at the consumer’s terminals falls due to the increased voltage drop in (i) alternator synchronous impedance (ii) transmission line (iii) transformer impedance (iv) feeders and (v) distributors. The reverse would happen should the load on the system decrease. These voltage variations are undesirable and must be kept within the prescribed limits (i.e. ± 6% of the declared voltage). This is achieved by installing voltage regulating equipment at suitable places in the power system.


                  Learning Objectives:

                  • To understand importance of voltage control
                  • To know different methods and location of voltage control
                  • To familiarize with voltage control methods used at generation, transmission and distribution level

                  Lecture Contents:

                    • Importance of Voltage Control
                    • Location of Voltage Control Equipment
                    • Methods of Voltage Control 
                    • Excitation Control (i) Tirril Regulator and (ii) Brown-Boveri Regulator
                    • Tap-Changing Transformers
                    • Auto-Transformer Tap-changing
                    • Booster Transformer
                    • Induction Regulators
                    • Voltage Control by Synchronous Condenser

                    • Module 09 : Power Factor Improvement

                      Introduction:

                      The electrical energy is almost exclusively generated, transmitted and distributed in the form of alternating current. Therefore, the question of power factor immediately comes into picture. Most of the loads (e.g. induction motors, arc lamps) are inductive in nature and hence have low lagging power factor. The low power factor is highly undesirable as it causes an increase in current, resulting in additional losses of active power in all the elements of power system from power station generator down to the utilization devices. In order to ensure most favorable conditions for a supply system from engineering and economical standpoint, it is important to have power factor as close to unity as possible.

                      Learning Objectives:

                      • To know basics of Power factor
                      • To understand disadvantages of low power factor and advantages of power factor improvement
                      • To familiarize different methods of power factor improvements
                      • To learn calculation methods of power factor correction and apply them in designing

                      Lecture Contents:

                      • Power Factor and Power Triangle
                      • Causes and Disadvantages of Low Power Factor
                      • Power Factor Improvement
                      • Power Factor Improvement Equipment
                      • Calculations of Power Factor Correction
                      • Importance of Power Factor Improvement

                    • Course Assessments