Lecture Notes
for
B.TECH. IV yr, VIIth Semester
( Electrical Engg.)
Subject Code: EE–7042
Subject: Advanced Power Transmission
FACULTY OF ENGINEERING
UNIVERSITY OF LUCKNOW
LUCKNOW
Prepared by:
Dr. Gaurav Gupta
Assistant Professor
Electrical Engineering Department
EE–7042
ADVANCED POWER TRANSMISSION
UNIT-I
EHV AC Transmission: Need of EHV transmission, standard transmission voltage,
electrical and mechanical considerations of EHV lines, surface voltage gradients in
conductor, distribution of voltage gradients on sub-conductors, Features of EHV transmission
lines.
UNIT-II
HVDC Transmission: DC links, components and configurations, converter station, operation
and controls of converters, characteristics, power control, starting and stopping of dc link.
UNIT-III
Flexible AC Transmission Systems: Fundamentals of ac power transmission, transmission
problems and needs, Mechanism of active and reactive power flow control, basic FACTS
controllers with application and principles of operation.
UNIT-IV
Introduction to Smart Grid - Working definitions of Smart Grid and Associated Concepts –
Smart Grid Functions – Traditional Power Grid and Smart Grid – New Technologies for
Smart Grid – Advantages –Indian Smart Grid – Key Challenges for Smart Grid.
UNIT-V
Power Quality: Overview and definition of power quality, Sources of pollution, power
quality disturbances, voltage fluctuations, unbalance waveform distortion, power frequency
variations, mitigation and control of power quality issues.
Text Books:
1. R. D.Begmudre, “Extra High Voltage AC Transmission Engineering”, New Age Int. Ltd.
2. K.R. Padiyar, “HVDC Power Transmission System”, New Academic Science Ltd.
3. N. G. Hingorani and L. Gyugyi, “Understanding FACTs: Concepts and Technology of Flexible
AC Transmission Systems”, Wiley India Pvt. Ltd.
4. K. S. Manoj, “Smart Grid: Concepts to Design”, Notion Press.
Reference Books;
1. S. Rao, “EHV-AC and HVDC Transmission Engineering & Practice”, Khanna Publishers.
2. E.W. Kimbark, “Direct Current TransmissionVol:1”, Wiley Interscience.
3. Math H. J. Bollen, “Understanding Power Quality Problems:VoltageSags and Interruptions”,
Wiley India Pvt. Ltd.
4. Y.-H. Song, A. T. Johns, “Flexible AC Transmission Systems (FACTS)”, IET publication.
5. S. Borlase, “Smart Grids: Infrastructure, Technology, and Solutions”, CRC Press.
Unit- 1
Introduction to EHV AC Transmission
STANDARD TRANSMISSION VOLTAGES
Voltages adopted for transmission of bulk power have to conform to standard specifications
formulated in all countries and internationally. They are necessary in view of import, export,
and domestic manufacture and use.
The following voltage levels are recognized in India as per IS-2026 for line-to-line
voltages of 132 kV and higher.
Nominal System Voltage kV 132 220 275 345 400 500 750
Maximum Operating Voltage, kV 145 245 300 362 420 525 765
There exist two further voltage classes which have found use in the world but have not been
accepted as standard. They are: 1000 kV (1050 kV maximum) and 1150 kV (1200 Kv
maximum).
The maximum operating voltages specified above should in no case be exceeded in any part
of the system, since insulation levels of all equipment are based upon them. It is therefore the
primary responsibility of a design engineer to provide sufficient and proper type of reactive
power at suitable places in the system. For voltage rises, inductive compensation and for
voltage drops, capacitive compensation must usually be provided.
NECESSITY OF EHVAC TRANSMISSION
With the increase in transmission voltage, for same amount of power to be
transmitted current in the line decreases which reduces I2R losses. This will lead
to increase in transmission efficiency.
With decrease in transmission current, size of conductor required reduces
which decreases the volume of conductor.
The transmission capacity is proportional to square of operating voltages.
Thus the transmission capacity of line increases with increase in voltage.
With increase in level of transmission voltage, the installation cost of the
transmission line per km decreases.
It is economical with EHV transmission to interconnect the power systems
on a large scale.
The no. of circuits and the land requirement for transmission decreases with
the use of higher transmission voltages.
ADVANTAGES
Reduction in the current.
Reduction in the losses.
Reduction in volume of conductor material required.
Decrease in voltage drop & improvement of voltage regulation.
Increase in Transmission Efficiency.
Increased power handling capacity.
The no. of circuits & the land requirement reduces as transmission
voltage increases.
The total line cost per MW per km decreases considerably with the
increase in line voltage.
