EXPERIMENTAL ANALYSIS OF THE OPTIMAL CAM CHARACTERISTIC FOR A KAPLAN TURBINE

Transcription

1 University POLITEHNICA of Bucharest Hydraulics, Hydraulic Machinery and Environment Engineering Department EXPERIMENTAL ANALYSIS OF THE OPTIMAL CAM CHARACTERISTIC FOR A KAPLAN TURBINE GEORGIANA DUNCA DIANA MARIA BUCUR CONSTANTIN CĂLINOIU EUGEN CONSTANTIN ISBĂŞOIU IGHEM 1 June 7-3, 1, Trondheim, Norway

2 AIM Considering the present efforts for increasing the green energy production, one of the easiest things to do is to optimize the operation of the hydro units. For existing Kaplan turbines, index testing and optimization are the best way to assure the maximum efficiency and power output. HPP Calimanesti Power output: x MW Designed net head: 1.5 m Rated discharge: x 185 m 3 /s

3 HPP CALIMANESTI LOCATION IN ROMANIA Romania Total surface: 38,391 km (water: 3%) Population (11): 19,4,936 Installed hydro power units: 6,4 MW Hydro energy production 11:.4 TWh 1: 19.9 TWh

4 HPP CALIMANESTI ON SIRET RIVER Siret River: - hidological basin surface: 8,116 km² (17% of total volume of Romanian water resources) - water course length: 76 km - medium discharge: m³/s - maximum discharge: 4,85 m³/s - minimum discharge: 35 m³/s

5 PROJECT OF SIRET RIVER CASCADE Missing dam - not built yet design level 6.5 mdmb real level 58.5mdMB

6 IN SITE DETERMINATION the guide vane opening, S ad, reported to the maximum opening; runner blades inclination, S r, reported to the maximum inclination; the level after the upstream grill, Z 1 ; downstream level, Z ; pressure difference indicated by the two pressure taps on the spiral case, Δh; electrical power, P g ; vibration of the turbine shaft; vibration of the turbine cover. Z 1 = 16 m Z =.8 m Z 3 = 15.4 m Net head: tot V1 V H n z1 z g V H n V Q 1 g g S1 S 1 1 z 1 z Reported discharge: Reported efficiency: * Q h h* ad r * P gq gc * H 1.94% nc

7 Results for the Original CAM characteristic Reported efficiency * - [-] Reported efficiency * - [-] Reported discharge Q * - [m.5 ] Power output P g - [MW] Hydro unit reported efficiency for the existing CAM relation depending on reported discharge and generator power output 7 Q P * c c Q * H H H P H nc n nc n 1 3 Runner blades opening S R - [%] Guide vane opening S AD - [%] Existing CAM relationship

8 Results for broken-off CAM characteristic 35.7% 5% 37.5% 5% % % Reported efficiency * - [-] % 15% Reported efficiency * - [-] % 15% Reported discharge Q * - [m.5 ] Power output P g - [MW] Reported efficiency for broke-off CAM combination with envelope curve defining optimal values % Guide vane opening S ad - [%] Guide vane opening S ad - [%] % 15% 5% 37.5% Reported discharge Q * - [m.5 ] Power output P g - [MW] Guide vane opening at broke-off combination with envelope curve defining optimal values

9 15.5 Original and Optimum CAM characteristic Original CAM Optimum CAM 15.5 Reported efficiency * - [-] Reported efficiency * - [-] Reported discharge Q * - [m.5 ] Reported efficiency for original and optimum CAM relation 1.5 Original CAM Optimum CAM Power output P g - [MW] 7 6 Generator power output at best efficiency point: 17.4 MW Runner blade inclination S r - [%] Original CAM H nc =.8 m H nc = 15.4 m H nc = 16. m Guide vane opening S ad - [%] Original and optimum CAM combination

10 Unit rotational speed n11 [rot/min] Theoretical analysis Unitary model characteristic of the turbine K Unit flow q 11 [m 3 /s] η tb Net head H - [m] a = 18.8 D D.84 M a = 1 a = 4 φ = η M a = 7 a = 3.89 φ = -1 D D M φ = Turbine mechanical power P - [MW] n n Operational characteristic of KVB turbine (a - guide vane opening, φ - runner blades inclination) M a = a = 36 a = 39 φ = φ = φ = a = 4 Theoretical turbine power output at best efficiency point: P T =18 MW D 1 = 5 m n = 83 rot/min Generator efficiency: G 95% Generator power output P G P T G 17.3MW

11 . VIBRATION ANALYSIS - TURBINE SHAFT Original CAM characteristic x [mm] x [mm] x [mm] y [mm] 8 MW power output y [mm] 15 MW power output y [mm] 18 MW power output Broken-off CAM characteristic x [mm] x [mm] x [mm] y [mm] approx. 8 MW, S r =.5% and S ad = 45% y [mm] approx. 15 MW, S r = 37.5% and S ad = 64% y [mm] approx. 18 MW, S r = 5% and S ad = 67%

12 VIBRATION ANALYSIS-TURBINE COVER Original CAM characteristic Broken-off CAM characteristic Amplitude [V] Frequency [Hz] FFT plot of the vibration signal on the turbine cover, original CAM characteristic, 15 MW power output Amplitude [V] Frequency [Hz] FFT plot of the vibration signal on the turbine cover, broken-off CAM approx. 15 MW, S r = 37.5% and S ad = 64%

13 University POLITEHNICA of Bucharest Hydraulics, Hydraulic Machinery and Environment Engineering Department CONCLUSIONS In this study field tests are performed for a hydro unit which equips a run of river HPP, first in the conditions of the actual CAM, then with the CAM relationship broken off. The efficiency is obtained at different runner blades and guide vanes position combinations across a range of heads. After analyzing the measurements results can be stated that the optimum CAM relation obtained by measurements is very different than the actual one. It can be seen that efficiency maximum shifts from a reported discharge of 9 m.5 to 8 m.5. The recommended optimum operation in terms of optimal CAM relation is m.5, which corresponds to a electric power output of 1 19 MW. It can be seen that the shape of the orbits obtained for the original CAM relation are tighter and irregular which indicates that in the new conditions of CAM relation the hydro unit has an improved behavior from the shaft vibration point of view. Regarding the turbine cover vibrations analysis, it can be seen that their amplitudes are decreased in the best efficiency point comparing to the values measured in the case of the original CAM characteristic. IGHEM 1 June 7-3, 1, Trondheim, Norway