This document provides information on the various auxiliary systems used in hydro power plants, including: - Braking and jacking, compressed air, heating/cooling, governing, cooling water, drainage, and mechanical auxiliary systems. - Electrical auxiliary systems like bus ducts, transformers, cables, switchgear, protection systems, and control/monitoring panels. - Operation procedures including pre-start checks, normal start/stop sequences, synchronization, and emergency handling. - Key components of sub-systems like pressure tanks, compressors, pumps, valves and details of lubrication, ventilation, fire protection and crane systems.

1. Hydro Power Plant Auxiliaries
Saurabh Mahajan
Assistant Director
NPTI-HPTC,Nangal

2. • Brake & Jacking System
• Compressed Air System
• Heating, Air-conditioning And Ventilation System
• Governing System
• Cooling Water System
• Drainage & Dewatering System
MECHANICAL AUXILIARIES
• Drainage & Dewatering System
• EOT Cranes
• Fire Extinguishing System
• Centralized Grease Lubrication System
• Oil Purification Equipment's
• Head Cover Drainage System

3. Practical braking speed 25-30% of rated speed
BRAKING & JACKING SYSTEM
Rotating Machine
Air for Brake
Oil for Jack

4. COMPRESSED AIR SYSTEM
High pressure compressed air system for governing control
system of generating units is provided common for all the units.
Compressed air systems comprises of two nos. suitable capacity
high pressure air compressors one working as main and the
other for stand by use, one common high pressure air receiver
for supplying high pressure compressed to governing pressure
vessels and one no. low pressure air receiver for supplying low
pressure air for generator breaks and for use of pneumatic toolspressure air for generator breaks and for use of pneumatic tools
during maintenance operation. The system consist of necessary
piping's valves, pressure switches, pressure reducer and
moisture removers. The capacity of the system shall be
sufficient to chart one oil pressure vessel from atmospheric
pressure to its normal working pressure in about 3 hrs,. The air
receiver shall be provided pressure switches for automatic start
stop control of compressor on sensing of low / high pressure in
the common air receiver. The air receiver shall be provided with
pressure gauge pressure switches for automatic control.

5. HEATING, AIR-CONDITIONING AND
VENTILATION SYSTEM
• The heating and air conditioning system is used for providing
a comfortable working temperatures in the control room and
offices for the power station. For this purpose air conditioners
with heating arrangement of suitable capacity are provided in
the control room / offices.the control room / offices.
• For ventilation of the power house and the battery room
exhaust fan are provided of suitable capacity to provide the
required air changes for creating comfortable working
environment for the operators. The exhaust fans are provided
near the roof of the power house.

6. GOVERNING SYSTEM
• HYDRAULIC TURBINE GOVERNOR
IS USED FOR CONTROLLING THE GUIDE
VANES BY DETECTING TURBINE SPEED &
ITS GUIDE VANE OPENING IN ORDER TOITS GUIDE VANE OPENING IN ORDER TO
KEEP TURBINE SPEED STABLE OR TO
REGULATE ITS OUTPUT.
• THE PERFORMANCE OF THE GOVERNOR
DOMINATES THE CONTROLLABILITY OF
THE POWER PLANT AND QUALITY OF AN
ELECTRICAL POWER PRODUCED .

7. OIL PRESSURE UNIT
• MAIN OIL PUMPS
• JACK OIL PUMP
• OIL PRESSURE TANK
• OIL SUMP TANK• OIL SUMP TANK
• ACTUATOR & CONTROL CUBICLE

8. Oil Pressure Unit
Supply pressurized oil to servomotor for opening or
closing of guide vanes under the command of governor.
oilair
Air inlet
To system
oilair

12. Oil Pressure Unit
• Pumping Set
– Pump
– Safety Valve
– Loading & Unloading Valve
– Directional Valve
• Storage Equipment
– Pressure Tank– Pressure Tank
– Isolating Valve
• Controlling Set
– Actuator
– Emergency Safety Valve
– Over speed detection control

13. Storage Equipment
• Pressure Tank /
Accumulator
– Used to store
pressure and
reduce hydraulicreduce hydraulic
shock
• Type
– Weight Type
– Bladder Type
– Piston Type
– Air/oil Type

14. Storage Equipment
• Bladder Type
– Consist of a Closed
rubber bladder
inside the forged
steel shell.
– Low cost for small
configuration
– Threat : Damage on
Bladder

15. Storage Equipment
• Piston Type
– Consist of a fluid
section and a gas
section with a piston
acting as a gas proofacting as a gas proof
screen. The gas
section is precharged
with dry nitrogen gas.
– Costly
– Threat : Leakage

16. Storage Equipment
• Air/Oil type
– Consist of a fluid at
the bottom and a
compressed air atcompressed air at
the top without any
medium for
separation.

17. Controlling Set
• Over speed Detector
– Tangential over speed
detector is a device
fitted to hydraulic
turbine as a second
safety added to thesafety added to the
electronic speed
threshold.
• Main components
– Detector
– Tripping Device
– Accessories

18. For large & medium turbines this system is
consist of a pumping set comprising two
or more positive displacement pumps
drawing oil from sump and delivering it
passed unloading and safety valves, throw
a non return valve, and into an oil/air
pressure oil vessel or pressure receiverpressure oil vessel or pressure receiver
whence it is fed to the Governor actuator
& main servo motor regulating valve.
Exhaust oil from servo motor is return to
the sump.

19. COOLING WATER
For cooling of
 Generator Stator Windings
• Bearings• Bearings
• Shaft Seals
• Transformer
• Fire Fighting

20. OPEN LOOP COOLING WATER SYSTEM
Air Coolers
(For stator)
Transformer’s
Coolers
Penstoc
k
Tail Race
Booster
Pump
Shaft Seal
Cooler
(For Turbine
Bearings)
Oil Coolers
(for Gen Bearings)
(For stator)
k

21. CLOSE LOOP COOLING WATER
SYSTEM
Transformer’s
Coolers
Tube
Well
Sprinkler
s
Booster
Pump
Shaft Seal
Cooler
(For Turbine
Bearings)
Oil Coolers
(for Gen Bearings)
Air Coolers
(For stator)
Coolers
Cooling Pond

22. DRAINAGE SYSTEM
POWER HOUSE
Intake Level
Cooling pump floor
Turbine floor
Tail Pool Level
Water
Drainage pit
Water
Water

23. DEWATERING SYSTEM
• The dewatering
system is generally
meant to dewater the
penstock, spiral case
and runner duringand runner during
their maintenance
and inspection works.

24. EOT CRANE
EOT Cranes are used in powerhouses during commissioning, maintenance
and repair of a hydro unit and their auxiliaries

25. EOT CRANES
Cranes:
The main traveling crane in a Power station plays a very
large part in the initial installation of Plant and thereafter
periodic overhaul of the main machines. The principle
lifts may be as much as 450 Ton but it is important thatlifts may be as much as 450 Ton but it is important that
the crane should also have convenient facilities for
dealing quickly with small loads, and for this purpose it is
usual to provide a high speed auxiliary hook capable of
handling about five to twenty five tons. The longitude
travel and transfer movements are usually motor
operated.

27. TOWER CRANE

28. GANTRY CRANE

29. FIRE EXTINGUISHING SYSTEMS
Types
•Automated sprinkler/spray protection
•Hydrant Service
•Hand appliances
•Gaseous systems for control rooms•Gaseous systems for control rooms
Sprinkler
Hoses Portable Extinguisher

30. OILPURIFICATION
EQUIPMENT'S:
In Hydro electric plant the lubricating and governor oil suffers
very little deterioration. However it may contaminated with
water, cement dust, metal particles or even with scale from
oil pipes and tanks. This may be done on a station basis
with a central oil storage and purification plant or by means
of small portable purifier which may be connected in turn toof small portable purifier which may be connected in turn to
various oil sumps. On a station basis two tanks are
provided, each of sufficient capacity to accommodate all
the oil from one unit. Clean and dirty oil pipe leads from
these tanks to each generating set. A portable pump is
provided to drain dirty oil from any sump and discharge it
through the dirty oil pipe to the dirty oil tank. This pump is
then used to draw oil from the clean tank and discharge it
through the clean oil pump to the empty machine sump.
The dirty oil is then passed through purification equipment
to clean tank where it is stored for further use.

31. CENTRALISED GREASE
LUBRICATION SYSTEM
• THIS SYSTEM PROVIDES GREASE TO
MOVING PARTS OF TURBINE AND MIV. ITMOVING PARTS OF TURBINE AND MIV. IT
CONSISTS OF GREASE RESERVOIR AND
PUMP MOTOR SET, PIPINGS & FITTINGS
AND CONTROL.

32. OIL LEAKAGE UNIT
• THIS UNIT IS PROVIDED FOR THE
COLLECTION OF OIL LEAKAGE
FROM SERVOMOTORS,FROM SERVOMOTORS,
CONTROLLING VALVES AND OIL
PIPE LINES. IT CONSISTS OF A
TANK, PUMPING UNIT.

33. HEAD COVER DRAINAGE
SYSTEM
• GRAVITY DRAINAGE
• SUBMERSIBLE PUMPS• SUBMERSIBLE PUMPS
• EJECTOR SYSTEM

34. ELECTRICAL AUXILIARIES
1. BUS DUCT:- These are used for carrying the current from the generator to
transformer. These could be the copper or aluminum material. These are
provided with clamps / connectors and fasteners for connection of different
strips depending upon the layout of the bus duct. In which the bus bars are
laid.
2.STATION SERVICE TRANSFORMER:- The main generator transformer are
installed in the switchyard for connecting the generating units to the
connecting bus bars. The kVA rating of the generators is about 10% higher
than the generator kVA. These transformers are used for stepping up
generation voltage to the transmission voltage. The main transformer could be
either one for each unit or one for two units.either one for each unit or one for two units.
3.STATION AUXILIARY TRANSFORMER:- The station auxiliary transformer
is also located closed to the main transformer. This transformer catters to the
operational load of all station auxiliaries and steps down the transmission /
generation voltage to 415V for use by the auxiliaries in the station.
4.XLPE CABLES:- For smaller station the power is transmitted thru XLPE
cables from the generators to the transformer and also from transformer to
switchyard for high voltage systems. These cables also connect the generator
LAVT and NGT cubicles power and auxiliary transformers and various
distribution boards to station auxiliary equipments. These cables are PVC
insulated heavy duty electrical cables.

35. ELECTRICAL AUXILIARIES
5. SWITCHGEAR:- The switch gear is used for isolating the generator
from the transformer the switch gear cubical is housed in the control
room. The voltage of the switch gear is the same as generation
voltage of the generator. These equipments are optimal rated and
are capable of operating under severest operating condition without
deterioration or damage and capable of withstanding the stresses
likely to develop under the severest fault condition. All these
equipments shall be suitable for symmetrical short circuit level and
shall be capable of withstanding of mechanical stresses resulting
from such faults. All clearances of life parts between phases andfrom such faults. All clearances of life parts between phases and
earth metal parts of switch gear and other equipment shall be
adequate for a max. service voltage of generation voltage + 10%
6. OUTDOOR SWITCH YARD:- Out door switchyard is used for
evacuation of power from the power station to the transmission
systems. It consists of Circuit Breakers for connecting the
transformer to the common bus bars, Isolators for isolating the bus
bars from the transmission line with insulators and steel structures
for mounting of the power cables and bus.

36. ELECTRICAL AUXILIARIES
7.CURRENT TRANSFORMER:- The current transformer are used
relaying and metering purposes of current. These are single phase
transformers. The burden and accuracy class of the CT’s provided shall
be educate for operation of the associated protected devices and
measuring instruments. The accuracy class of metering shall be better
than 0.5. The current transformers will safely withstand the effect of
temperature, wind load, tensile forces and movement of connections as
well as short circuit forces. These are located in the swtichyard. The CT
will be rated for 120% of rated primary current.
8. VOLTAGE TRANSFORMER:- Low voltage transformer metering8. VOLTAGE TRANSFORMER:- Low voltage transformer metering
operated as a group of three- star connected on 50 cycles, 3phase
system. The voltage transformer single phase, 4 type, oil immersed,
self cooled out door type suitable for used on the 10% higher voltage
over the transmission voltage. The voltage transformers will safely
withstand the effect of temperature, wind load, tensile forces and
movement of connections as well as short circuit forces. These are
located in the swtichyard. The VT will be rated for 120% of rated
primary current.

37. ELECTRICAL AUXILIARIES
9. DC SYSTEMS:- The DC system is provided to provide 110V DC supply for
control protection indication annunciation and emergency lighting etc. The DC
systems consist of the following one set of battery bank depending upon the
station load requirements one battery charger, one DC distribution panel and DC
distribution boards for the respective equipments.
10.CONTROL & MONITORING SYSTEM:- The control & monitoring systems
are provided to control the operation of the unit and to monitor the different
parameters of equipment for proper operation and safety of the units. For this
purpose various type of panel are provided in the machine hall as well as control
room. The different type of panel are Turbine Control and Metering Panel,
Generating Control and Metering Panel, Annunciation Panel, TemperatureGenerating Control and Metering Panel, Annunciation Panel, Temperature
Measurement Panel, Generator Protection Panel, LAVT Panel, NGT Panel,
Governor Panel, Excitation panel, LTAC Panel for auxiliaries, Fire extinguisher
Panel, Break Control Panel and Synchronizing Panel. These panels are duplicated
in the control room with a additional control desk for centralized operation of the
units.
11.PROTECTION SYSTEM:- The protection system is meant for signal
processing issuing commands to output section and are revaluating the kind of
shut down to be initiative like normal shut down or emergency shut down. A
100% relay back up is provided for protection function the faults for the field
activate the master trip relays directly shut down the unit under emergency
conditions.

38. ELECTRICAL AUXILIARIES
12.DG SETS:- DG set installed to supply the power to the station auxiliaries in case
of grid failure to start the unit the capacity of the DG set station auxiliaries required to
operated the unit or to meet emergency conditions.
13.ILLUMINATION SYSTEM:- The Illumination system is provided for illuminating
the power house control room switchyard and other surrounding area. The system
will consist of lighting distribution board / panels, fixtures junction boxes,
convenient socket outlets, welding sockets, cable glands etc. The normal standard
of the illumination will be :
• Control Room 500 lux
• Office Room 300 lux
• Switch yard 150 lux
• Power House 50 lux
• Other area and stair cases 50 lux
• The system shall cover normal / emergency lighting design for 415 / 240 V
AC, 3-phase systems and critical lighting for 110V DC systems.
14.LTAC PANEL:- LTAC Panel comprises of one no. main incoming feeder and an
emergency feeder from the DG set and out going feeder. The LTAC Panel will be feed
from station auxiliary transformer which is connected to the bus bar. The station
auxiliary transformer supply will be consider preferential feeder to provide the
required interlocking to ensure continuous power supply to 415 V auxiliary bus. In
case of failure of supply from station auxiliary transformer DG set feeder breaker will
close automatically to supply the powered to the auxiliaries.

39. Operation of a Hydro Unit
• Pre Start Checks
• Start Sequence
• Synchronization
• Stop Sequence• Stop Sequence
• Monitoring during operation
• Tripping
• Emergency Handling

40. Pre Start Checks
Many of the start checks may be built up in the
starting interlocks and starting sequence. The
abnormality if any, will appear in MMI display
and “Unit ready to start” indication does not
appear. The list of activities/checks varies from
station to station.

41. ROTORPole
C
oo
ler
In
Gen Shaft
Pole
Stator Winding
GGBCool
Water
cooler
TRCM
Oil
DC Excitation
Restore AC & DC supply to auxiliaries
Reset relay
Open Draft Tube GateBrake releasedCooling chargedUnit ready to startOpen Intake gateH S Lub startOpen GVMachine start rolling100% speedVoltage Build up
Unit
Ready
To
Synchronize
START SEQUENCECheck PTW
T
R
A
N
S
F
11 KV
220KV
Tur
Shaft
ler
In
Gate
DT
Gate
G
V
G
V
Water
Thrust Pad
Hot
water
HS
LUB
Water
F
O
R
M
E
R

42. Synchronization
Trans
Transmission line
Close CB when V, F &
Ph matches
Stator 11KV 220KV
Rotor
Rotor Pole DC
excitation by closing
FCB
CB
+
_

43. Monitoring during operation
Operate machine as per schedule & water level
• Attend any alarm appearing in control room
• Temperature of bearings/stator/transformer
• Cooling water flow
• Leakage water level in turbine pit• Leakage water level in turbine pit
• Operation of drainage pumps.
• Generator Voltage and reactive Power flow.
• Machine vibrations.
• Abnormal sound from the machine.
• Fill up hourly log sheet

44. Stop Sequence
Reverse to start sequence

45. Tripping of Machine on Fault
Stop machineStop machine
Note down relayNote down relay
Inform Maintenance staffInform Maintenance staff

46. Emergency Handling
Increase in water level inside Power House
• Raise Alarm.
• Intimate Power Station Incharge.
• Try to stop the source of leakage water.
• If the leakage is from the machine immediately close the intake gate after
opening the generator circuit breaker and giving stop command to the
machine.
• Ensure that Power Supply to Drainage & Dewatering pumps is not shut
down.
• Run the available drainage / dewatering pumps or any other available
pumps to pump out the water.

47. Emergency Handling
Fire
• Raise Alarm.
• If fire is in the machine or Transformer give stop command.
• Release CO2 or water through fire protection system .
• Intimate fire station.• Intimate fire station.
• Inform Power Station authority
• Try to isolate other equipment from the source of fire.

48. Thank You.Thank You.