Power System Engineering

Dr. Ganesh B. Kumbhar gkumbfee@iitr.ernet.inPhone: 01332-28-4752

Introduction Power System provides vital service to the society and mankind. Electrical power is somewhat like air we breathe: We think of it only when

it is missing. Modern society cannot exists without electricity. Therefore, it should be operated with the following objectives

minimize operating cost maintain balance between generated power and load including

interchange transactions maintain nominal frequency maintain operating conditions within equipment rating maintain voltage within permissible limits maintain power reserves in order to minimize the risk of loss of load in

the event of random generator outages meet pollution constraints

Historical Background 1870's and 1880s; DC power systems were popular. Small systems were sold to factories around

the world, both in urban areas, and remote undeveloped areas for industrial/mining use. 1882: Power station at Pearl Station New York by Edison supplying power to 59 consumers,

110 V DC, Cable 1.5 km, lamp load. 1884: Motors were developed 1886: Limitations of AC become apparent, higher losses and voltage drops. 1889: AC transmission line 4kV, single phase, in north America between Willamette falls to

Portland by Westinghouse. 1893: First three phase line in Southern California, 12 km, 2.3 kV, 1995: Niagara falls AC power plants (>40 km, 2.3 kV), phenomenal growth in

electric companies, 1922-1990: 165 kV -> 1100 kV 1920: Europe standardized 60 Hz and suspended insulators for HV. 1954: HVDC transmission system by Swedish Power Board. 1972: Back-to-back connected HVDC station providing asynchronous tie between power

systems Quebec and New Brunswick.

Voltage Levels Vs. Year

Year Voltage Level1922 1651923 2201935 2871953 3301965 500 kV1966 765 kV1990 1100 kV

Introduction We are witnessing enormous development in terms of voltage rating, power

ratings, components, architecture, planning, etc.

Modern power system are vast electrical networks inter-connecting hundreds of rudimentary systems spread over a country giving rise to national grid.

Advantages of interconnections: Reduced reserve capacity

Reduced capital cost

Effective and economic use of available generation

Improved reliability and operational efficiency

Disadvantages Fault propagation

Higher circuit breaker ratings

Proper management of dispatch of power

Introduction Power system is the branch of electrical engineering where we

study in depth for its design, operation, maintenance and analysis. Power System Engineering is one of the important and core

subject of electrical engineering. The ease of transmission of electrical energy gives rise to a

possibility to a generating electrical energy in bulk at the centralized place and transmit it over large distance to be used by a large number of users.

Component needed for generation, transmission and distribution of electrical energy form a huge complex system termed as Electric Power System.

The development of power system has contributed to the phenomenal advances of human kind over past century.

Syllabus

Syllabus

Syllabus

Syllabus

Introduction Power System provides vital service to the society. Electrical power is somewhat like air we breathe: We

think of it only when it is missing. Modern society cannot exists without electricity. Therefore, it should be operated with the goal of achieving

Highest reliability standards

Lowest operational cost

Minimum environmental impact

Historical Background 1882: Power station at Pearl Station New York by Edison

supplying power to 59 consumers. 1889: AC transmission line 4kV, single phase, in north

America between Willamette falls to Portland by Westinghouse.

1893: First three phase line in Southern California. 1954: HVDC transmission system by Swedish Power Board. Modern power system are vast electrical networks inter-

connecting hundreds of rudimentary systems spread over a country giving rise to national grid.

We are witnessing enormous development in terms of voltage rating, power ratings, components, architecture, planning, etc.

Basic Structure of the Power System In India, power system mostly owned by states called as

State Electricity Boards (SEBs). There are five Regional Electricity Boards (REBs):

EREB, WREB, NREB, SREB, NEREB. Then, there are Central Govt. Organizations: NTPC,

NHPC, NPC, etc. Also, PGCIL responsible for bulk power transfer through

extra high voltage transmission. The modern power system can be classified as generation,

transmission and distribution.

Structure of Power System

Power Generation Power generation takes place in power plants which may

be geographically dispersed.

Power plant may house more than one generating unit.

Sources of Energy: Hydrocarbons (Oil, coal, natural gas, etc.)

Water

Nuclear

Chemical

Solar

Wind

Tidal

Installed Generating Capacity (in MW) in India

24% 64% 3% 8%

Transmission Network

Connect generating plants to the consumption points: use remote energy sources.

Interconnect power pools: Reduce generation reserve and cost, increase reliability.

High Voltage AC transmission

HVDC transmission

High Voltage Transmission

Lower transmission losses/MW transfer.

Lower line voltage drop/ km.

Higher transmission capacity / km

Reduce right of way requirement /MW transfer

Lower operating cost / MW transfer

Power Transmission Equipments Step-up and Step-down

Power Transformers.

Voltage regulator

Phase shifter

Transmission lines and cables

Circuit breakers and isolators

Shunt and series reactors and capacitors

Lightning arresters

Protective relays

Fact devices (SVC, Statcom, TCSC, etc.)

Converter and Inverter

Standard Transmission Voltages in India AC Transmission

765 kV

400 kV

220 kV

132 kV

HVDC Transmission 400 kV

500 kV