Hydro Penstock Monitoring

A hydro generating station in the Lac Saint Jean region of Quebec wanted to increase the efficiency of the operation of their turbines by measuring the flow rate going through their penstocks. Maximum productivity and guaranteed revenue are the main priority for hydropower plant operations. With this consideration, turbine efficiency plays a decisive role and measuring the flow rate going through a 4.3 meter diameter with the greatest degree of accuracy is no easy feat. Their goal was to keep their purchasing and installation costs down which provided for more interesting challenges when measuring flows accurately through a 4.3 meter diameter pipe.

Up until recently, the standard method of measuring penstock flow, or flows in very large pipes would by a multi-path ultrasonic transit time method. The measuring principle is based on the proven and highly accurate ultrasonic transit-time method, whereby the system measures and determines the path velocities and computes the flow rate and volume bi-directionally. Multiple sensor paths using sensor pairs are strategically located internally inside the pipe either through insertion from the exterior of the pipe, or internally. Various transit times between sensor pairs in this multi path arrangement are measured and averaged out to provide a highly accurate system. Thanks to this extremely high measurement accuracy, measurement values are used to determine turbine efficiency.

GWF (formerly known as Hydro-Vision of Germany) had introduced a multiple path transit time flowmeter using Clamp-On transit time flow transducers. This method makes measuring flow non-intrusive and easy to install from the outside of the pipe. The transducers are installed with little technical effort and without process interruption on the pipeline.

Cancoppas technicians performed the installation and commissioning of two 4 path sensor systems on two 4.3 meter diameter penstock pipes. Each installation was performed by two technicians in less than 2 days each. Accuracies of better than 1% of reading were achieved and the customer is happy with the end result.

Installations of Clamp-on transducers have never been easier. Unique mounting concepts with magnetic frames allow for either a temporary or permanent fix (by use of adhesive or stainless steel-straps). Watertight transducer covers are also available for rugged installation environments. Removal of these sensors for cleaning, repair or replacement is possible without process interruption.

GWF Clamp-On sensors