Method and device for determining suction height of variable speed units

A method for determining a suction height of a variable speed unit, comprising the following steps:

• acquiring a reference cavitation coefficient and a reference specific rotation speed parameter corresponding to a target water head section in a preset number of power stations;
• conducting calculations on the reference cavitation coefficient and the reference specific rotation speed parameter by utilizing a target scheme to obtain a target formula, wherein the target formula is used for obtaining a statistical relationship between a cavitation coefficient and a specific rotation speed;
• acquiring a maximum lift value, a minimum lift value, a speed variation range and a synchronous rotation speed value of a current target variable speed unit and input force values of the target variable speed unit at a plurality of key working condition points;
• and
• determining a target suction height of the target variable speed unit according to the maximum lift value, the minimum lift value, the speed variation range, the synchronous rotation speed value, the input force values at the plurality of key working condition points, and the target formula,
• wherein the determining the target suction height of the target variable speed unit according to the maximum lift value, the minimum lift value, the speed variation range, the synchronous rotation speed value, the input force values at the plurality of key working condition points and the target formula comprises:
• determining flow values of the target variable speed unit at the plurality of key working condition points according to the input force values at the plurality of key working condition points;
• obtaining a specific rotation speed value at each key working condition point according to the flow value under each key working condition, the maximum lift, the minimum lift, the synchronous rotation speed value and the speed variation range;
• and
• determining the target suction height according to the specific rotation speed value at each key working condition point and the target formula;
• wherein the determining the target suction height according to the specific rotation speed value at each key working condition point and the target formula comprises:
• determining a first cavitation coefficient maximum value corresponding to the maximum lift within the speed variation range and a second cavitation coefficient maximum value corresponding to the minimum lift within the speed variation range according to the specific rotation speed value at each key working condition point and the target formula;
• obtaining a suction height minimum value according to the first cavitation coefficient maximum value, the second cavitation coefficient maximum value and a suction height calculation formula;
• and
• obtaining the target suction height according to the suction height minimum value.