table 2. Mechanical checks for turbine components. Equipment Maintenance and Repair Checklist Turbine * Coatings condition and repairs of water passages * Welding repair in water passages area * Vibration-monitoring system * Supervisory control and data acquisition controls to avoid rough zone operation * Modification adopted to improve efficiency * Air-injection system to reduce vibration and rough zone operation Runner * Repair on runner surface due to loss of material by cavitation; checking amount of material welded * Runner modification to improve cavitation and efficiency performance * Runner wear ring replacement * Runner replacement Wicket gates * Improvement of wicket gate design and profile * Bushing replacement * Seal type and replacement due to excessive leakage * Improvement of operating mechanism * Break pin failure * Bushing lubrication type and operating ring segments Guide bearing * Pad or surface repair/replacement * Repair of antifriction material (Babbitt) * Improvements to lubrication and oil cooling system * Temperature register Turbine shaft seal * Contact surface repair (shaft sleeve) * Wear segment type, modifications for improvement * Failures of wear segment rings Governor system * * * * * * * Accumulator replacement Pump/motor replacement Improvement to the filtration system Hydraulic component replacement System oil replacement Oil sample testing system Distributor and pilot valves repairs or replacement * * * * * * Surface coating repairs Internal seal adjustment and repairs Bushing replacement Shaft seal replacement Actuator replacement Valve replacement Turbine inlet valve figure 5. The unit 3 generator floor. 42 ieee power & energy magazine and water level measurements throughout each test. Power measurements were recorded in the control room during each test point. Following the testing, a fluorometric analysis was carried out to do a precise comparative analysis of the amount of dye (fluorescence) in the samples. This analysis was conducted to determine the sample water dye concentration, which is used to calculate the absolute flow rate. Once the data analysis had been completed, turbine efficiency curves were generated for each plant. These curves were used for comparison against hypothetical upgraded turbine efficiency curves to estimate revenue increases for the various upgrade options. A sample turbine efficiency curve for Acaray II is shown in Figure 9. These curves were subsequently used by the long-term planning model (Vista DSS) to calculate revenue increases for upgrade options, as described in the following sections. table 3. The condition assessment test. Test Standard Reference Equipment Stator winding resistance IEEE 115 Generator Winding insulation resistance IEEE 115 Generator Controlled high-voltage test IEEE 95 Generator Dissipation factor and tip-up IEEE 115 Generator Partial discharges IEEE 115 Generator Temperature sensors status IEEE 62.2 Generator Penetrant dye test to rotor spider IEEE 115 welding Generator Insulation of collector rings IEEE 115 Generator Excitation high-voltage test IEEE 421 B Exciter Stator core tightness check IEEE 62.2 Generator Rotor winding resistance IEEE 115 Generator Rotor winding insulation resistance IEEE 115 Generator figure 6. The unit 4 Francis runner cavitation inspection. september/october 2020