Impulse turbine multi-nozzle switching method

The invention discloses an impulse turbine multi-nozzle switching method. The method comprises the steps of 1) numbering N nozzles of the turbine, and setting N-1 opening values to serve as switching points; 2) entering step 3) and step 4) respectively when opening increasing or decreasing instructions are sent on the outside of the turbine; 3) comparing the nozzle openings with the opening values of the switching points, controlling the nozzles to be locked or increase the openings till the last N nozzle openings are 100%; 4) comparing the nozzle openings with the opening values of the switching points, controlling the nozzles to be locked or reduce the openings till the N nozzle openings are 0; 5) cycling the step 2) to the step 4). By means of the method, multi-nozzle free switching can be achieved, the unit load impact during switching is small, the switching is accurate and reliable, the water energy usage efficiency is improved, and the turbine operation is stable.