Micro Hydro Schemes

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Micro Hydro Schemes

• Basic Maintenance Practices

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Content of Presentation

• Components of a Micro Hydro Scheme
• Why proper Maintenance is important ?
• Intake and Dam
• Settling Basin and Channel
• Fore Bay Tank and Penstock
• Turbine and Accessories
• Generator
• Electronic Control and Switchgear
• Safety Installations
• Distribution Network

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Components of a Micro Hydro Scheme
Source Adam Harvey, et.al.,(1993),Micro Hydro
Design Manual A Guide to Small Scale Power
Schemes, London
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Why Proper Maintenance ?
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Intake and Dam

• Check the walls of the dam structure and intake
  for erosion especially during rainy season to
  avoid leakages and cracks
• Make sure that water level is maintained at a
  safe level (not too much or too little)
• Add specified lubricants to the gears and threads
  at least once every month
• Lock the water gate rail when it is not used
• Empty and clean the dam once every 1 or 2 months
  to avoid sediment and trash build up
• Clean the trash and debris that clog the trash
  rack daily
• Empty and clean the intake to avoid sediment and
  trash build up

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Intake and Dam
GOOD
BAD
BAD
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Settling Basin and Channel

• Settling Basin
• Small soil particles settle in the settling basin
  therefore it is important to flush the basin
  regularly to avoid proper functioning. Reduced
  volume of tank as a result of sedimentation will
  cause soil particles to enter the penstock and
  damage the turbine
• Channel
• Check whether there are leakages along the
  channel and repair accordingly
• Check the soil condition on the banks of the
  channel for risks of land slides during rainy
  season
• Clean the channel from grasses or other growth
  that can reduce the speed of water in the channel

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Channel
GOOD
BAD
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Fore Bay Tank and Penstock

• Fore Bay Tank
• Check water level to ensure it is operating
  properly and safe (no overflow)
• Clean the tank from trash and sediment
• Clean the trash rack regularly
• Check whether there were leakages and cracks on
  the tank, take immediate actions if there are
  leakages or cracks
• Penstock
• Check penstock for leakages at joints or on the
  pipe
• Check bolts and nuts at joints and anchor block
  to avoid position movement
• Check soil condition surrounding penstock and
  anchor block and make sure that there is no risk
  slides or soil movement
• Repaint the penstock at least once every 3 years
  to avoid rusts

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Fore Bay Tank and Penstock
GOOD
BAD
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Turbine and Accessories

• Precaution MAKE SURE THE TURBINE IS NOT RUNNING
  WHEN CHECKING THE INNER COMPONENTS OF THE TURBINE
• Check nuts and bolts on the turbine body. Make
  sure that all are in firm condition
• Lubricate rotating parts once every 2-3 weeks and
  screw threads such as bearings do not over
  grease the bearings ! Remove surplus grease!
• Check and clean inside part of the turbine at
  least once every 6 months. Make sure that there
  is no foreign solid material inside
• Clean the body of the turbine from dirt and
  moisture to avoid rust weekly
• Check for abnormal temperature of the turbine
  especially at the bearings!
• Check for abnormal position of turbine
• Check for abnormal noise of the turbine

GOOD
BAD
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Generator

• Precaution DO NOT TOUCH THE ELECTRICAL
  CONNECTION WHILE THE GENERATOR IS OPERATING
• Check the tightness of nuts and bolts of the
  generator
• Check for abnormal temperature of the generator
  everyday. Abnormal temperature is a condition
  when one can not comfortably touch the generator
  body using the palm of the hand
• Check for abnormal noise or vibration and also
  abnormal smell from the generator
• Clean the ventilation and generator fan from dust
  when the MHP scheme is not in operation
• Check the tension level of the transmission belt.
  Make tension adjustment if needed

GOOD
BAD
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Electronic Control and Switch

• Precaution MAKE SURE THE MHP SCHEME IS OFF WHEN
  CHECKING THE ELECTRONIC CONTROL
• Check the cable connection, secure the connection
  when it is not firm enough and replace it if
  damaged
• Clean the panel from dust and other things such
  as spiders webs etc.
• Make sure the panel is secure from any water
  entering the powerhouse
• Clean up ballast tank (if using water cooled
  ballast) and make sure the ballast tank is always
  full
• Check the grounding cables whether they are
  connected properly to the control cubicle,
  generator body, penstock and other metal
  components

GOOD
BAD
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Distribution Network

• Precaution MAKE SURE THE SCHEME IS SWICHED OFF
  WHEN CHECKING DISTRIBUTION CABLES
• Check the network for damage due to falling tree
  branches etc.
• Make sure (by regular clearing) that no tree
  branches can fall on or grow into the cables
• Check the cable poles periodically for damage
  such as rot, insects, leaning etc.
• Check the conductor cables for damage or
  looseness. Replace if necessary with the same
  type of cable
• Check regularly the house installations. Make
  sure that the connections are still in good
  condition and there is no electricity theft or
  illegal installations (pilfering)

GOOD
BAD
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Safety Installations

• MAKE SURE that all safety measures originally
  applied remain in place
• Front door of electric panel
• Transmission belt covers
• Protection fences (around transformers, fore bay
  tank etc.)
• Electric isolation devises
• Make sure that only trained people who have to
  be exposed to the technical installations (power
  house, transformer stations, civil constructions)
  can gain access to them

GOOD
BAD