K-chamber Pressure Control for Kaplan Turbine Runner Leakage Test Based on Incremental PID Method

The leakage test of the Kaplan turbine runner requires the operation of the blades to open and close twice to three times per hour. The blade movement and leakage of the sealing device are observed during this process. The movement of the blade servomotor will cause pressure fluctuations in the leakage chamber (K-chamber) of the runner. The test requires the pressure to be maintained at $0.5 \pm 0.05 \mathrm{MPa}$ and be held for twenty-four hours. To achieve pressure stability in the K-chamber, in this paper, a test system adopting the incremental Proportional-Integral-Derivative (PID) control algorithm is proposed, which drives the proportional valve in Pulse Width Modulation (PWM) mode.