Experimental investigation into the rapid reserve generating capability of Francis-type turbines

The potential for Francis turbines to provide rapid frequency control services is examined experimentally on a scale model turbine following rapid inlet guide vane opening from a modified synchronous condenser mode. The resulting two-phase flow in the draft tube is presented visually while the output response of the turbine is monitored during the rapid transition to generation mode. Laboratory findings are compared to full scale test results of a 119 MW Francis turbine unit.