for collage work

1. SILIGURI INSTITUTE OF TECHNOLOGY
DEPARTMENT OF ELECTRICAL ENGINEERING
Presentation on :
HYDRO POWERPLANT GENERATION
Presented by
Name : Arnab Chakraborty, Shuvajit Sarkar, Subhankar
Roy, Subhrajit Dutta
Roll : 11901621017, 11901621019, 11901621027,
11901621028
Department : Electrical Engineering
Semester : 7th

2. Introduction
A hydropower plant is a facility designed to generate electricity by harnessing the energy of
moving or falling water. These plants use the force of water to turn turbines connected to
generators, converting the kinetic energy of the water into electrical energy.
Introduction to TLDP -IV
Teesta Low Dam - IV Hydropower Plant is a run-of-the-river hydroelectric station built on the Teesta River at
Kalijhora, Kalimpong district, West Bengal.
Teesta Low Dam–IV power station (4X40 MW) is a run of the river scheme with diurnal storage for peaking
purpose. The Power Station was commissioned in the year 2016. The Project model, layout plan features and
photo gallery of the Power Station are detailed below.

3. How a
hydroelectric
power plant
works
Water Source: Located near a river or dam with a significant water flow.
Reservoir: A dam creates a reservoir at a higher elevation, storing a large amount of water.
Water Intake: Water is collected from the river or reservoir and directed into the power plant.
Penstock: The water flows through a large pipe (penstock) to guide and control its flow towards the
turbine.
Turbine: Water strikes the turbine blades, causing it to spin and transfer mechanical energy to a
connected shaft.
Generator: The spinning turbine turns the generator's rotor, converting mechanical energy into
electrical energy through electromagnetic induction, usually producing alternating current (AC).
Transformer: Generated electricity passes through a transformer, increasing its voltage
for efficient transmission.
Transmission Lines: High-voltage electricity travels through transmission lines in the
power grid to distribution points, from where it can be further distributed to homes,
businesses, and industries.

4. Powerhouse
•A hydroelectric power plant utilizes spillway radial gates for water storage,
maintaining the full reservoir level (F.R.L) at 182.25m and the minimum draw
down level (M.D.D.L) at 179m. Power generation occurs between these
levels, with a tail water level (T.W.L) of approximately 155.4m for four
generating units.
•The net head is 25.05m, and the powerhouse produces 160MW
(4X40MW), with a net power output of around 43.6MW after losses. Water
is channeled through penstocks to Kaplan turbines (BHEL, 6 blades) at a rate
of 716 cumecs. Turbine rotation (125-473 R.P.M) generates power electro-
mechanically coupled to alternators.
•Guide vanes control water flow, with an adjustable angle of 0 to -0.5
degrees. BHEL generators have a fixed stator and a rotating rotor, generating
power through faraday's law. A cooling system prevents overheating.
•Each unit has a governing system for power balance and load demand.
Two units operate, two under construction, synchronized for parallel
operation via lamp-test. Power factor (leading/lagging) is determined by
checking excitation system parameters. Power is stepped up from 11KVA to
224KVA by 3-phase transformers, then transmitted to the switchyard for
distribution.

5. Generator
•The generator used in TLDP-IV is synchronous generator.
There is total four generators, each generating 40MW each.
Synchronizing of a Generator
Four Parameters are to be checked while synchronizing:
• Phase sequence
• Frequency
• Phase angle
• Voltage Magnitude
•The rotor field windings is connected to the slip rings.
•220V DC supply is given in the slip rings which provides
rotor field.
excitation to the
• 11kV of voltage is generated in the stator part of the generator.
•Bus bars are used for the transmission of power from one equipment to
other.
• Here turbine is working as prime mover for the generator.
• Coupler is used to connect the turbine shaft with generator shaft.
Important points of the Generator:

6. Types of
Transformers
There are various types of transformers used in TLDP – IV. They are:
• Generator step up transformer – 11KV/220KV, 50MVA
This type of transformer plays a vital role in boosting the electricity produced by
the generator and then transferring it to the switchyard.
• Unit Auxiliary Transformer– 11KV/415V, 1MVA
It is a power transformer that provides power supply to the auxiliary equipment’s
inside a power station.
• Excitation Transformer 11KV/415V, 845KVA
An excitation transformer is a device that is used to excite the rotor field by means
of power supply in the rotor field windings.
• Sub Station transformer – 11KV/415V, 2000KVA
This transformer is basically used when there is no unit running and we need a
power supply to charge the boards (UAB, SSB). It steps down 11KV into 415V. This
415V is used to charge the boards present in the 3rd. floor (Control Room). This
11KV is taken from WBSEDCL.

7. Switch yard
• Electricity from the powerhouse goes to the switch yard on the Teesta
River's left bank. The 200m x 95m switch yard at an elevation of 212m
distributes power through three feeders: NJP-1, NJP-2, and TLDP-3,
generating 720 MU annually at 2.96 KWH cost, including 12% free power to
the state.
• Power, stepped-up to 224KV, goes to the switch yard with MAIN BUS-
1(224KV) and MAIN BUS-2(224KV). Incoming power passes through
switching and breaking circuits before distribution to the main bus-bars,
including four lines - GT-1, GT-2, GT-3, and GT-4.
In a single line diagram:
1. Incoming line through Lightning Arrester (L.A/S.A), Current Transformer
(C.T), and Constant Voltage Transformer (C.V.T).
2.Line then goes to a Circuit Breaker (C.B) before reaching main bus-bars.
Salient Points:
• I) C.T/C.V.T/P.T - Send signals to the relay or control system, checking values
before Circuit Breaker activation.
• ii) Spring action of C.B - Disconnects conducting terminals during
under/over-voltage, using SF gas to prevent danger.
• iii) Wave trap - Used to avoid disturbances on high voltage lines caused by
cable wires carrying signals with high frequency.

8. Conclusion
The NHPC hydroelectric power plant
training provided invaluable insights
into the intricate workings of a modern
hydroelectric facility. Through a
comprehensive exploration of the
plant's components and processes, we
gained a deeper understanding of the
synergy between engineering,
technology, and environmental
considerations.