HYDROPOWER TECHNICIAN – IHA CERTIFICATION EXAM
QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES 2025|2026 Q&A | INSTANTDOWNLOAD
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1.
The primary factor determining hydropower potential at a site is:
• A. Soil fertility
• B. Head and flow
• C. Turbine size
• D. Reservoir area
Correct because the energy available is proportional to water head and flow
rate.
2.
Which turbine is most efficient for high-head, low-flow applications?
• A. Kaplan
• B. Francis
• C. Pelton
• D. Crossflow
Correct because Pelton turbines are impulse machines designed for high-
head, low-flow sites.
3.
What is the function of the draft tube in a reaction turbine?
, • A. Increase water flow velocity
• B. Prevent cavitation
• C. Recover kinetic energy and improve efficiency
• D. Cool turbine bearings
Correct because draft tubes convert kinetic energy into pressure energy,
increasing efficiency.
4.
In a hydro generator, the excitation system provides:
• A. Speed regulation
• B. Lubrication
• C. DC current to the rotor field winding
• D. Cooling water circulation
Correct because excitation supplies the rotor magnetic field needed for
generation.
5.
Which dam type is most suitable for narrow, rocky valleys?
• A. Earthfill
• B. Arch dam
• C. Gravity dam
• D. Buttress dam
Correct because arch dams transfer water pressure to valley walls, ideal for
narrow sites.
6.
,If a turbine efficiency is 90% and generator efficiency is 95%, the overall efficiency
is:
• A. 85.5%
• B. 85.5%
• C. 92.5%
• D. 95%
Correct because total efficiency = 0.90 × 0.95 = 0.855 (85.5%).
7.
Run-of-river plants typically have:
• A. Small or no reservoir storage
• B. Large multipurpose reservoirs
• C. High seasonal storage
• D. Pumped storage capacity
Correct because run-of-river systems depend directly on river flow, with
minimal storage.
8.
The governor in a hydropower plant primarily controls:
• A. Voltage
• B. Turbine speed and flow
• C. Excitation current
• D. Generator cooling
Correct because governors regulate water flow to maintain turbine speed
and frequency.
, 9.
Cavitation in turbines is caused by:
• A. Excessive lubrication
• B. Overheating
• C. Low pressure causing vapor bubble collapse
• D. High sediment levels
Correct because cavitation forms vapor bubbles that collapse, damaging
turbine blades.
10.
Which hydropower plant type can also provide grid stability through fast
response?
• A. Run-of-river
• B. Pumped storage
• C. Arch dam
• D. Mini-hydro
Correct because pumped storage acts like a battery, quickly balancing grid
load.
11.
Which material is most commonly used for turbine runners?
• A. Aluminum
• B. Stainless steel
• C. Brass
QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES 2025|2026 Q&A | INSTANTDOWNLOAD
1.
The primary factor determining hydropower potential at a site is:
• A. Soil fertility
• B. Head and flow
• C. Turbine size
• D. Reservoir area
Correct because the energy available is proportional to water head and flow
rate.
2.
Which turbine is most efficient for high-head, low-flow applications?
• A. Kaplan
• B. Francis
• C. Pelton
• D. Crossflow
Correct because Pelton turbines are impulse machines designed for high-
head, low-flow sites.
3.
What is the function of the draft tube in a reaction turbine?
, • A. Increase water flow velocity
• B. Prevent cavitation
• C. Recover kinetic energy and improve efficiency
• D. Cool turbine bearings
Correct because draft tubes convert kinetic energy into pressure energy,
increasing efficiency.
4.
In a hydro generator, the excitation system provides:
• A. Speed regulation
• B. Lubrication
• C. DC current to the rotor field winding
• D. Cooling water circulation
Correct because excitation supplies the rotor magnetic field needed for
generation.
5.
Which dam type is most suitable for narrow, rocky valleys?
• A. Earthfill
• B. Arch dam
• C. Gravity dam
• D. Buttress dam
Correct because arch dams transfer water pressure to valley walls, ideal for
narrow sites.
6.
,If a turbine efficiency is 90% and generator efficiency is 95%, the overall efficiency
is:
• A. 85.5%
• B. 85.5%
• C. 92.5%
• D. 95%
Correct because total efficiency = 0.90 × 0.95 = 0.855 (85.5%).
7.
Run-of-river plants typically have:
• A. Small or no reservoir storage
• B. Large multipurpose reservoirs
• C. High seasonal storage
• D. Pumped storage capacity
Correct because run-of-river systems depend directly on river flow, with
minimal storage.
8.
The governor in a hydropower plant primarily controls:
• A. Voltage
• B. Turbine speed and flow
• C. Excitation current
• D. Generator cooling
Correct because governors regulate water flow to maintain turbine speed
and frequency.
, 9.
Cavitation in turbines is caused by:
• A. Excessive lubrication
• B. Overheating
• C. Low pressure causing vapor bubble collapse
• D. High sediment levels
Correct because cavitation forms vapor bubbles that collapse, damaging
turbine blades.
10.
Which hydropower plant type can also provide grid stability through fast
response?
• A. Run-of-river
• B. Pumped storage
• C. Arch dam
• D. Mini-hydro
Correct because pumped storage acts like a battery, quickly balancing grid
load.
11.
Which material is most commonly used for turbine runners?
• A. Aluminum
• B. Stainless steel
• C. Brass
