The presentation will give you brief idea about the operation of hydro power plant which includes pre-check conditions, starting and stopping sequences, loading of unit, emergency stopping, parameter monitoring and control.

1. Operation of Hydro Power Plants
Dinesh Prasad
dineshprasad04215@gmail.com

2. Topics to be covered
Pre-check conditions
Starting & Stopping sequences
Loading of unit
Emergency Stopping
Parameter monitoring and control

3. Layout of Presentation
• Unit Operation Control
• Pre-Check Conditions
• Starting Sequence
• Parameter Monitoring & Control
• Stopping Sequence
• Emergency Stopping

4. Unit Operation Control(1)
• Manual control
• Semi-automatic control
• Fully automatic control
• Offsite supervisory control

5. Unit Operation Control(2)
Manual Control:-
In this type of control, the chain of the pre-
starting checks, starting, synchronizing, loading
and stopping is selected and performed in turn by
hand whether mechanically or by push buttons.

6. Unit Operation Control(3)
Semi-automatic control:-
In this type of control, from a single manual starting
impulse a unit may be brought to the ready to
synchronize condition by the automatic selection,
performance, and providing of a sequence of
controls.
Likewise a similar stopping impulse completely
shutdown the unit.
Synchronizing and loading control remain manual
functions from the local and remote control, points.

7. Unit Operation Control(4)
Fully automatic control:-
In this type of control, means are provided for
running up, automatically synchronizing and
loading up to a predetermined quantity on receipt
of a single starting impulse. Subsequent manual
variations of loading and excitation may be
provided as a remote control function.
The corresponding stopping impulse will cause the
load to be reduced, the unit to be disconnected
from the bus bars and the turbine to be shutdown
completely.

8. Unit Operation Control(5)
Offsite supervisory control:-
Starting, stopping, switch closing or opening and
other functions initiated from a remote point,
together with indications of successful
operations of voltage and load control and of
the repetition of alarm conditions at the remote
control point. The equipment is ancillary to
either semiautomatic or fully automatic unit
control.

9. Unit Operation Control(6)
Control Hierarchy of Hydro-electric Plants:-
Control category Subcategory Remarks
Location Local Control is local at the controlled equipment or within sight
of the equipment.
Centralized Control is remote from the controlled equipment, but
within the plant.
Offsite Control location is remote from the project.
Mode Manual Each operation needs a separate and discrete initiation;
could be applicable to any of the three locations.
Automatic Several operations are precipitated by a single initiation;
could be applicable to any of the three locations
Operation
(Supervision)
Attended Operator is available at all times to initiate control action
Un-attended Operation staff is not normally available at the project site

10. Pre-check conditions(1)
There is no work-permit , outstanding.
Intake gate fully open.
Draft tube gate is fully open.
Protective devices reset.
Wicket gates closed.

11. Pre-check conditions(2)
Control supply(Generally DC) to Unit control
Board(UCB), Control & Metering Relay(CMR)
Panel, Excitation system, Governor cubicle etc.
are healthy.
AC supply to UCB, CMR and all unit auxiliaries
are made ON.
Governor in automatic position.
OPU Pressure is normal.
Oil level in the lubrication system normal.

12. Pre-check conditions(3)
Compressed air system normal.
Brake pressure is normal.
Cooling water supply to bearing coolers & shaft
seal is healthy.
Guide vane servomotor lock is released.
Space heaters of generator are OFF.
Generator/GT Circuit Breaker is open.
All temporary earthling arrangements are removed
off live conductors/wires.

13. Pre-check conditions(4)
All earth switches in Generator/GT bay of
switchyard are open.
Generator brakes are released.
Generator field breaker is open.
Water level normal.

14. Pre-check conditions(5)
Many of the above checks and operations may
be built up in the starting interlocks and starting
sequence. These variations are to be checked
with particular Power Station.

16. Unit Operation Sequence
• Unit operation sequence refers to the safe
operation of machine in a particular sequence,
without any damage to plant and its associated
equipment's, thereby giving birth to successful
generation.
• Starting sequence
• Stopping sequence

17. Starting Sequence(1)
4 steps:-
1. Generally opens the main inlet valve & start unit
auxiliaries.
2. The turbine is started and brought up to speed no
load and field breaker is closed.
3. The paralleling of the unit is carried out & unit is
synchronized with generator bus by closing the
Generator/GT circuit breaker.
4. Loading of the unit is carried out up to a preset
value.

18. Starting Sequence(2)
Starting the Unit:-
 Ready to start signal appears in control room
 Start command is given.
 Inlet valve opening sequence starts
By pass valve opens
Spiral casing pressurized
Inlet valve opens
By pass valve closed.
 H.P. oil injection pump starts.

19. Starting Sequence(3)
Cooling Water flow to bearings, stator coolers and
transformer cooler starts and cooling water
established relay energized.
Open command given to guide vane limiter.
 Guide vanes open to start position.
 Machine starts rolling.
 Machine speed reaches 80%.

20. Starting Sequence(4)
Governor starts functioning.
Machine speed reaches 90%.
Generator Field excitation starts.
Generator Voltage reaches normal.
Machine ready to synchronize.
Note down the starting time of machine.

21. Starting Sequence(5)
Synchronization of Unit:-
 Inform RLDC and receiving-end about synchronization.
 Check that Bus selection isolator is in close position.
 Check that Bus Bar is charged.
 Make the synchronizing selector switch on.
 Match voltage & frequency of the Generator with that
of the grid.

22. Starting Sequence(6)
Make synchro-scope indicator start rotating in
clock-wise direction at a very slow speed.
Close Circuit Breaker at 11o’clock position of
synchro-scope indicator.
Increase the Power Generation by Power Raise/
Lower switch.
Note down the synchronization time of the unit.

24. Parameter monitoring and control(1)
 Attend any alarm appearing in control room
 Identify critical points of the Power station Like :-
• Temperature of bearings.
• Temperature of Stator.
• Temperature of Generator Transformers.
• Cooling water flow in shaft seal different bearings,
stator air cooler, transformer cooler and running of
pumps, choking of coolers.

25. Parameter monitoring and control(2)
• Leakage water level in turbine pit.
• Running of drainage/dewatering pumps.
• Voltage at HV Bus and reactive Power flow.
• Stator & field currents.
• OPU Pressure and oil level in OPU
Pressure tank (should not be high)
• Oil level in bearings.
• Machine vibrations.
• Abnormal sound from the machine.

26. Parameter monitoring and control(3)
Take hourly reading of Tail water level.
Obtain hourly reading of Dam water level from
Dam Control Room.
Fill up hourly log sheet for various parameters of
the machine.
Co-ordinate with RLDC and Remote end for any
shutdown of machine/ line and major change in
generation.

30. Stopping Sequence(1)
 Inform RLDC and receiving end.
 Reduce the load of the machine slowly.
 When load is reduced around 10-15% of full load, open the
generator C.B.
 Check that C.B. has opened.
 Give stop command
• Generator C.B. opens if not open already.
• Generator Field breaker opens and closing starts.

31. Stopping Sequence(2)
• Guide vane is closed.
• Machine retards.
• The bearing H.P. oil pump starts,
• At 25% of rated speed, Generator Brakes are
applied.
• Machine comes to stand still.
• H.P. Oil pump stops.
• Generator Brakes released.

32. Stopping Sequence(3)
 Cooling water to stator, transformer and bearings is closed.
 G.V. servomotor is locked.
 Generator Isolation (EHV) is opened
 Make a record of time of opening of Generator C.B. and
stopping of machine.

34. Emergency Stopping(1)
TRIPPING OF MACHINE ON FAULT(1):-
Protection relay operates  Trip Relay operates.
Generator C.B. is opened.
Generator Field breaker is opened.
Closing command is given to guide vanes and inlet
valve.
Stop sequence starts as in case of manual stopping
of the machine.
Note down the operated protection relays, flags
after ensuring that machine has stopped.

35. Emergency Stopping(2)
TRIPPING OF MACHINE ON FAULT(2):-
 Take print out of Sequential Event Recorder.
 In case of tripping of lines/load throw-off, communicate
with remote end and get information about operation of
relays at receiving end. Also take print out of Sequential
Event Recorder (SER) & Fault Disturbance Recorder.
 Intimate maintenance staff giving as much detail as
known.

36. Emergency Stopping(3)
Increase in water level inside Power House :-
1. Raise Alarm.
2. Intimate Project In charge.
3. Try to stop the source of leakage water.
4. 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.
5. Ensure that Power Supply to Drainage & Dewatering pumps
is not shut down.
6. Run the available drainage / dewatering pumps or any other
available pumps to pump out the water.

37. Emergency Stopping(4)
Fire:-
1. Raise Alarm.
2. If fire is in the machine or Transformer
• Give stop command.
• Release CO2 or water through mulsi fire system as per
the provision .
3. Intimate fire station.
4. Try to isolate other equipment from the source of fire.

38. Thank You