To provide the students with an opportunity to acquire knowledge, skills and attitude in the area of transmission and distribution electrical energy with special emphasis on:

• Different types of transmission and distribution systems of electrical energy.
• Comparison of different types of transmission and distribution system.
• Electrical and mechanical design of overhead lines.
• Survey of transmission and distribution line route.
• Performance calculation of overhead transmission line.

SHORT DESCRIPTION

Supply system: Different systems of transmission; Aspect of system loss; Mechanical design of overhead lines: support of overhead lines; conductors & conductor materials; Insulators; Effect of sag; Methods for survey of transmission/distribution line route; Voltage distribution of suspension insulator; Corona; Erection of poles and drawing of conductors of overhead line; Electrical design of overhead line: Resistance of the line conductor; Skin effect of transmission line; Effect of inductance on transmission line; Effect of capacitance of overhead transmission line; Performance of transmission lines: Voltage regulation and efficiency of short transmission line.

DETAIL DESCRIPTION

Theory:

SUPPLY SYSTEM

• Understand different systems of transmission of electrical energy.
  • Explain the transmission and distribution system of electrical energy.
  • Categorize various systems of transmission and distribution of electrical energy.
  • Define Feeder and Distributor.
  • Compare betⁿ feeder & Distributor.
  • Compare between overhead and underground transmission and distribution system.
  • Explain the advantages of high voltage transmission over low voltage transmission.
  • Compare the cost of conductor of different overhead systems.
  • Compare the cost of conductor of underground system with overhead system.
  • Describe the process of choosing the working voltage for transmission and distribution system.
  • Calculate the most economic working voltage for transmission of electrical energy.
  • Express the equation for the most economic size of conductor by Kelvin’s law.
  • Solve problems on Kelvin’s law.
  • Describe the limitations to the application of Kelvin’s law.
• Understand different aspects of system loss.
  • Explain the term system loss
  • List the factors involved in system loss.
  • Explain how system loss can be minimized.
  • Discuss the most economic power factor.
  • Express the equation for most economic power factor.
  • Solve problems on most economic power factor.

MECHANICAL DESIGN OF OVERHEAD LINES

• Understand the supports of overhead lines.
  • List the main components of overhead lines.
  • Categorize the line supports.
  • Describe different types of line supports.
  • Mention the characteristics of line supports.
  • Describe the vibration dampers.
• Understand the conductors and conductor materials.
  • List different types of line conductors used in overhead transmission and distribution lines.
  • Mention at least five properties of conductor materials.
  • Compare the properties of copper, aluminium and ACSR conductors.
• Understand the line insulators and their characteristics.
  • List different types of insulators.
  • List insulator materials.
  • Describe the propertie of insulators materials.
  • Describe the pin and suspension type insulators.
  • Compare the advantages and disadvantages of pin and suspension type insulator.
  • Mention the uses of different types of insulator.
  • List the causes of failure of insulators.
  • Explain different types of test of insulators.
• Understand sag and its effect.
  • Explain the sag of transmission line.
  • List the factors affecting the sag.
  • Explain the spacing between conductors and span length.
  • Express the deduction of the formula to calculate the sag of conductors between two poles of equal height.
  • Express the deduction of the formula to calculate the sag of conductors between two poles of unequal heights considering effect of ice and wind pressure.
  • Solve problems on sag of transmission line.
  • Explain the effects of vibration on the transmission line and prevention of vibration.
  • Describe the measure for the prevention of vibration.
• Understand the methods for survey of transmission / distribution line route.
  • List the survey instruments required for survey of transmission / distribution line.
  • Explain the uses, errors and accuracy of survey instruments.
  • Describe the process of measuring the angles by compass, level and theodolite.
  • Explain leveling, alignment, surveying and pegging of the route.
  • Explain the methods of measuring vertical and horizontal heights.
  • List the principle factors in routing overhead power lines.
• Understand the voltage distribution of suspension insulator.
  • Explain string efficiency.
  • Describe the methods of improving string efficiency.
  • Solve problems on string efficiency.
  • Express the deduction of equation for voltage distribution across each unit of a string of suspension insulators.
  • Describe the methods of voltage grading in suspension insulators.
  • Describe the method of equalization of voltage of suspension insulators by guard ring.
  • Solve problems on voltage distribution and voltage grading.

• Understand the phenomenon of corona.
  • Define corona of overhead transmission line.
  • Discuss the effect of corona.
  • Explain at least four factors that affect corona.
  • Describe the advantages and disadvantages of corona.
  • Express the derivation of the relation for disruptive critical voltage, visual critical voltage and power loss due to corona.
  • Discuss the methods for minimizing corona.
• Understand the erection of poles / towers and drawing of conductors of overhead line.
  • Describe the procedure of erection of poles of overhead transmission / distribution line.
  • Describe the procedure of erection of towers of overhead transmission line.
  • Describe the procedure of fixing crossarm and insulator.
  • Describe the drawing of conductors of overhead line.
  • Describe the erection of stay / guy wire.

ELECTRICAL DESIGN OF OVERHEAD LINE

• Understand the resistance of line conductor.
  • Describe the line constant of transmission line.
  • Express the deduction of the equation for calculating resistance of the line conductor.
  • Solve problems on the resistance of the line conductor.
• Understand the skin effect of transmission line.
  • Explain the skin effect of transmission line.
  • Express the equation for calculating skin effect resistance.
  • Explain the proximity effect.
• Understand the effect of inductance on transmission line.
  • Explain the flux linkage of a conductor due to internal and external flux.
  • Express the deduction of the equation for inductance of a single phase and three phase overhead transmission line in terms of Geometrical Mean Distance (GMD) and Geometrical Mean Radius (GMR).
  • Solve problems on inductance of single phase and three phase lines.
  • Describe the inductance of three-phase line with double circuit.
  • Explain the transposition of line conductors.
• Understand the effect of capacitance of overhead transmission line.
  • Explain the electric potential of a transmission line.
  • Express the derivation of the equation to calculate the capacitance of single phase and three phase overhead transmission line.
  • Solve problems on capacitance of single phase and three phase overhead transmission line.
  • Explain the capacitance of double circuit three phase overhead line.
  • Explain Ferranti effect.

PERFORMANCE OF TRANSMISSION LINES

• Understand the voltage regulation and efficiency of short transmission line.
  • Classify overhead transmission line.
  • Express the equation to calculate voltage regulation of overhead short transmission line.
  • Express the equation to calculate efficiency of overhead short transmission line.
  • Identify the effect of load power factor on voltage regulation and efficiency of overhead short transmission line.
  • Draw vector diagram of short transmission line performance calculation.
  • Solve problems on voltage regulation and efficiency of overhead short transmission line.

Practical:

• Survey and estimate the electrical loads of an area.
  • Select the area / section of which the electrical loads are to be surveyed.
  • Observe and record the load of each point of the area.
  • Calculate the amperage of the area and the sub-area.
  • Calculate the load of main circuit and sub-circuits.
• Plot the integrated load curve, actual load curve and ideal load curve.
  • Draw the integrated load curve.
  • Draw the actual load curve.
  • Draw the ideal load curve.
• Perform the selection of economical voltage for generation, transmission and distribution of electrical power.
  • Select generating voltage.
  • Select voltage for transmission and distribution of electrical power.
  • Select required type of insulators and poles.
• Prepare the layout diagram of an electrical project.
  • Draw the layout of the selected electrical project.
  • Draw the complete wiring diagram of the electrical project showing transmission line, distribution line and service mains.
  • Indicate the power source.
• Perform the identification of different components of LT and HT over head lines.
  • Identify the components of LT over head lines.
  • Identify the components of HT over head line.
  • Follow safety paractices.
  • Prepare a report.
• Perform the measurement of the horizontal distance between poles.
  • Collect the instruments/ equipment commonly used in surveying.
  • Measure the horizontal distance between poles over different ground conditions using tape and chain.
  • Record the measurement of distance.
  • Plot the line route showing the measurements.
• Perform the measurement of the angles and heights of poles / towers.
  • Select the instruments for measuring angles and heights of poles.
  • Measure horizontal angles.
  • Measure vertical angles.
  • Measure vertical heights of poles / towers.
• Survey and level the power lines.
  • Visit an actual high voltage power line route covering a distance of approximately five span.
  • Record ground levels, angle of route, interfering obstacles and length.
  • Draw a ground profile of the line route, showing the support positions and ground clearance on river crossing and canal crossing.
• Perform the measurement of sag of a transmission / distribution line.
  • Fix up the sag boards.
  • Set the theodolite in proper position.
  • Measure the sag of a transmission / distribution line using theodolite.
  • Prepare a report.