Study on Measurement of Penstock Head Loss for Hydropower Station with Multiple Units Per Penstock

Abstract

For a hydropower station with multiple units per penstock, how to get the head loss of penstock has usually been a difficult problem, which the core issue is that it is hard to obtain the flow of each branch pipe. For power stations that have installed flow measurement devices for all units, or have undergone absolute turbine efficiency tests, the head measurement is relatively simple, but if the flow measuring device is not installed for each unit in advance, the head loss measurement will be difficult. This paper proposes an optimized measurement method performed in a hydropower station in Pakistan, which is to arrange an ultrasonic flowmeter on the main penstock, and then use the Winter-Kennedy method and flow rate measured by Ultrasonic flow meter to calibrate the Winter-Kennedy coefficients of unit one by one. Finally, by running three units at the same time and adjusting them with the same flow rate, the total loss of the penstock is calculated. At the same time, the flow rate measured by the Winter-Kennedy coefficient and that measured by the ultrasonic method has been checked and compared. The result proves that the accuracy of the result is high, and the result has a good consistency, which can fully meet the requirements of penstock head loss calculation and evaluation. The method has a certain practical value and can be referred to by other power station which has similar measurement.