Field Performance Evaluation of Hydro Power Stations Brochure

• Visual Inspection
• Functional Checks
• Measurements and Tests

• Developed capability to carry out Field performance/efficiency testing as per IEC 60041:1991, IEC 62006:2010 and AHEC-IITR: OCT.2012.
• Performance evaluation/ efficiency test of over 240 hydropower plants of various capacities in different terrain and states have been carried out .

• Various methods applied for discharge measurement and head measurement.
• Providing technical consultancy and efficiency testing of pump/turbine.

Visual Inspection

• General inspection
• Inspection of civil works (diversion, water conductor system, power house and tailrace)
• Inspection of electrical equipment (control panels, power transformers etc.)
• Inspection of mechanical equipment (turbine, governor system, cooling system)

Measurements and Tests

• Unit Efficiency Test
• Error Test on Measuring Instruments
• Operational Tests on Protective Relays
• Vibration Measurements
• Sound Level Measurements
• Load Rejection Test
• Maximum Power Output Test

Functional Checks

Verification the operation functioning of the components subsystems and shortcomings defects, if any, are recorded.

• Control Panels: Functional checks on external accessories (lamps, push buttons, switches, digital indicators, buzzers, hooters etc.) and internal accessories (panel lights, panel light switches, space heaters, thermostats etc.).
• Fault / Status Annunciators: Component check, test, accept and reset functions.
• Circuit Breakers: Trip and close functions.
• Master / Trip / Auxiliary Relays: Operate and reset functions.
• Control / Regulating Devices: Flow / head regulating devices, excitation voltage control, speed governor control, power factor control,, manual start / stop operations, manual / auto synchronization, local / remote control of transformer tap changer, etc

Methods of Unit Efficiency Measurement by Discharge Head Method

• Absolute value of the discharge through the turbine.
• Net water head available at the turbine, and
• Electrical power output of the machine.
• Uncertainty in the measurement by this method is ±2% to ±4% depends on type of instrument used.

• Clamp-on Transit Time flow-meter (Uncertainty ±2.5% to ±3.5%)
• Intrusive Type transit flow meter (Uncertainty ±1% to ±2%)

• Ultrasonic sensors are clamped outside/ inserted (intrusive type) of the penstock.
• Mounting of sensor depends on the diameter of penstock.

• Measurement of net head requires measurement of total head at the inlet and that at the outlet, respectively, of the turbine and using their difference.

Head Measurement in Pressure Channels (Uncertainty ±0.5%)

• Electronic pressure gauge is connected to the pressure manifold which is required to fabricate as per IEC 60041:1991 at intake of turbine.

• Free water surface is measured separately near the intake point and the opening of the draft tube from ultrasonic level sensors (ULS).

• A reference digital wattmeter with an accuracy class of 0.2 or better is connected in parallel with the panel wattmeter of the generator.
• A test terminal block (TTB) or sliding-link type terminals, if provided in the metering panel, would facilitate connecting the reference wattmeter without shutting down the machine.

• The electrical power output of the generator is calculated by multiplying the reference wattmeter reading with CT ratio and VT ratio.

• Vibrations measured at each bearing of the generating units on no-load condition.
• Both rms displacement and rms velocity of the vibrations in the frequency band of the 1 Hz to 1 kHz are measured.
• Measurement is done at four mutually perpendicular locations on the bearing, and both along axial and radial directions.

• Sound level measured in "weighting factor A" mode near the machines at no-load conditions.
• Readings are taken 1 m away from the surface of generator, turbine, flywheel and gear box (as applicable) at right angle to the machine shaft, both on upstream and downstream sides of the machine.

• The generating unit under test is initially loaded to its rated value and its speed is noted down.
• The maximum sound level near the machine is also recorded on the basis of sound level test.
• The load on the machine is then suddenly rejected using the emergency shutdown push-button switch and the peak values of the speed and sound level (at the same point) attained consequently are noted.
• The maximum rise in the speed is compared with run-away speed of the generator as specified by its manufacturer.

• In the case of SHP stations of high heads (100 m and above), the hydraulic efficiency of the turbine can be measured by thermodynamic method.
• It involves accurate measurement of the small temperature rise of water that takes place between intake and outlet of the turbine due to losses from inlet to outlet. Pressure measurement is also conducted to determine head, but discharge is not required being one of the major advantage of this method.

• The overall efficiency of the generating unit is determined by assessing the hydraulic & mechanical losses in the turbine and in its auxiliaries and all losses including electrical and mechanical in the generator.

• Thus the method is suitable when the efficiency of the turbine alone is required and not the complete generating unit. Thermodynamic method has lesser uncertainty as compared to efficiency measured by any other discharge measurement method.

Three Phase Power Analyzer

Single Phase Power Analyzer

Ultrasonic Transit Time Flowmeter - Clamp On

Ultrasonic Transit Time Flowmeter - Clamp On

Ultrasonic Transit Time Flowmeter - Clamp On

Ultrasonic Transit Time Flowmeter - Intrusive Type

Ultrasonic Transducer - Intrusive Type

Ultrasonic Transducer - Intrusive Type

Ultrasonic Flat Transducer - Intrusive Type

Propeller Current Meter

Propeller Current Meter

Area Velocity Flowmeter

Ultrasonic Level Sensor

Pressure Transmitter

Submersible Pressure Transducer

Pressure Calibrator

Vibration Meter

Sound Level Meter

Thermometer

Temperature Sensor

Thickness Gauge

Underground Pipe Leakage Detector

Total Station

Relay Tester

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