This power plant is located in Tadali, Chandrapur and is owned by CESC Ltd. It has a total generating capacity of 2 * 300MW. One of the units is scheduled to be commissioned in October 2012. The plant uses coal to generate steam which powers turbines that drive generators to produce electricity. It includes various components like coal conveyors, pulverizers, boilers, condensers, cooling towers and transformers. The document then discusses electricity transmission systems and describes the overhead, underground, bulk power transmission and sub transmission levels in detail. It analyzes losses at different transmission levels and factors affecting losses like resistance, inductance, capacitance and power factor. Finally, it discusses the grid failure that occurred on July

1. Dhariwal’s Thermal
power plant
A production of CESC Ltd.

2.  This power plant will be governed by “CESC”
[calcutta Electric Supply company] ltd. located in
Tadali, at chandrapur MIDC region.
 The total estimated power generating capacity of this
plant is 2*300MW. Presently CESC Ltd is the
flagship company of RP-SANJIV GOENKA
GROUP.
 The project is almost on the verge of completion and
the commissioning date of its one of the two units is
somewhere around October 2012.
Introduction

3. Electrical system
Generation Transmission Distribution
System System System
Classification of electrical system

4. Generation process

5. Coal is unloaded by electric traction system at Coal Yard
Coal is crushed to finer pieces of order 20 mm
Pulverization of Coal
Coal is sent to furnace with the help of FD fan
Steam is generated at 540°C and 135 kg/sq.m
Steam is sent to Super heater
Superheated steam is sent to turbine
Production of Electricity by the generator coupled with turbine
Basic idea of Electric generation

6.  Coal Conveyer
 Pulverizer
 Boiler
 Condenser
 Cooling towers
 Economizer
 Air pre-heater
 Electrostatic precipitator
 Generator
 Transformer.
Elements of thermal power station

7. Transmission system

8. Transmission system
Overhead
Transmission
Underground
Transmission
Classification of transmission
systems

9.  Electric power can also be transmitted by
underground power cables instead of overhead power
lines.
 This type of transmission is mainly done in
congested areas where there is no space to set up
overhead line’s set up.
 Underground cables take up less right-of-way(ROW)
than overhead lines, have lower visibility, and are
less affected by bad weather.
 This also ensures safety for the commutators on busy
and congested streets.
Underground transmission

10.  Cost of insulated cable and excavation are much
higher than overhead construction.
 Faults in buried transmission lines take longer to
locate and repair.
 Underground lines are strictly limited by their
thermal capacity, which permits less overload or re-rating
than overhead lines.
 Long underground cables have significant
capacitance, which may reduce their ability to
provide useful power to loads.
Limitations of underground
systems

11.  Generally for high voltage transmission purpose OHT system
is used.
Conductors
 The conductors are made up of ACSR material & is not
insulated.
 Conductor sizes range from 12 mm2 to750 mm2 with varying
resistance and current carrying capacity. Use of thicker wires
may lead to skin effect.
 Because of this current limitation, multiple parallel
cables(bundle conductors) are used when higher capacity is
needed. Bundle conductors are also used at high voltages to
reduce energy loss caused by corona discharge.
Overhead transmission systems

12. Bulk power transmission level

13.  Efficiency, redundancy, network safety & economical factors must
be taken care about, during bulk power transmission.
 This level of transmission system includes transmission grids
which uses components like power lines, cables, switches, circuit
breakers & transformers.
 Transmission efficiency is hugely improved by step-up xmer
and proportionately reduce the current in the conductors, thus
keeping the power transmitted nearly equal to the power input.
 The reduced current flowing through the line reduces the losses in
the conductors.
 According to Joule’s Law energy losses are directly proportional to
the square of the current. Thus, reducing the current by a factor of 2
will lower the energy lost to conductor resistance by a factor of 4.

14.  Transmission efficiency plays an important role in
transmission system. More the efficiency less will be the
losses.
 Losses are occurred in transmission mainly bcz of following
three effects associated with conductors:
 Resistive effect
 Inductive effect
 Capacitive effect
Transmission line losses

15.  Transmitting electricity at high voltage reduces the fraction of
energy lost to resistance. For a given amount of power, a
higher voltage reduces the current and thus the resistive losses
in the conductor.
 In an A.C. circuit, the inductance and capacitance of the phase
conductors can be significant.
 The currents that flow in these components of the circuit
impedance constitute reactive power, which transmits no
energy to the load. Reactive current causes extra losses in the
transmission circuit. The ratio of real power to apparent power
is the power factor.
 As reactive current increases, the reactive power increases
and the power factor decreases thereby increase the losses.

16.  For systems with low power factors, losses are higher than for
systems with high power factors.
 Utilities such as capacitor banks and other components such
as
1. phase-shifting transformers;
2. static VAR compensators;
3. physical transposition of the phase conductors;
4. flexible AC transmission systems, FACTS
throughout the system to control reactive power flow for
reduction of losses and stabilization of system voltage.
 As the transmission level goes down losses become less than
what we’ve observed in higher levels.

17. Sub transmission level

18.  Sub transmission is part of an electric power transmission
system that runs at relatively lower voltages.
 High voltages is stepped down and sent to smaller substations
in towns and neighborhoods.
 Sub transmission circuits are usually arranged in loops so that
a single line failure does not cut off service to a large number
of customers for more than a short time.
 While sub transmission circuits are usually carried on
overhead lines, in urban areas buried cables(Under ground
cable network) may be used.
 At the end a step down transformer is used to serve low
voltage of the ratings 230 volts for residential areas.

19. Grid Failure on July 31,2012.

20. States affected by grid failure

21. Corridor where the fault occurred.

22.  When the whole northern and north-eastern region
was facing severe power cut India’s oldest private
sector operator the 113 year old CESC decoupled
from the faltering Grids in time isolating itself from
the chaotic breakdown.
 Supply from CESC plants operating at full steam was
back within minutes providing power to both the
Calcutta Metro and thousands of its consumers when
most of the nation faced a blackout.
A point to be noted.

23.  What CESC achieved was not rocket science.
 Load sensors at its synchronizing point at Howrah
detected the demand supply imbalance in the
connecting WBSEB grid.
 The Sanjiv Goenka led management was alert
enough to isolate itself before being sucked into the
demand surge from the northern grid that caused a
total collapse.
How does it happen?

24. Now the Questions arises that:
 Why sensors and protective relays of the Power Grid at
Agra, Lucknow or any other high demand synchronizing
point in the Northern Grid did not isolate the demand
centers from the grid on Monday night ?
 Were the load sensors not operating?
 Were the protective relays bypassed?
 Were the Under Frequency Relays out of service?
 Was the operating staff not empowered to switch off the
overdrawing units?
 Or whether the overload detection mechanism did not
function?
WHY??????

25. Thank you 
A presentation by Sandeep A. Jamdar