This document discloses a solution for analysing cavitation in a hydro turbine of a hydroelectric power plant. According to an aspect, a method comprises: measuring, by using at least one motion sensor coupled to a rotor of the hydro turbine, motion of the rotor during operation of the hydro turbine and thereby generating measurement data; acquiring, by at least one processor, the measurement data and one or more operational parameters of the hydro turbine employed during said measuring, the one or more operational parameters indicative of power supply of the hydro turbine; computing, by the at least one processor on the basis of the measurement data and the operational parameters, at least one metric indicative of an effect of the cavitation on the hydro turbine; comparing, by the at least one processor, the at least one metric with at least one threshold and determining, on the basis of the comparison, that the effect of the cavitation is too high; and outputting, by the at least one processor on the basis of said determining, information indicating unsuitability of the one or more operational parameters.

A hydraulic machine of the Francis-type includes: an impeller with blades; a guide vane assembly with a ring of guide vanes, a vane-free space extending between the impeller and the guide vane assembly; and at least three resonators for suppressing pressure fluctuations, the resonators respectively including a chamber and a tube connector, the tube connector being connected to the chamber, the tube connector including an end that faces away from the chamber and that opens into the vane-free space, the resonators being configured for suppressing the pressure fluctuations occurring during the operation of the hydraulic machine, the resonators being arranged at a uniform distance from each other in a circumferential direction around the impeller, and the resonators being adjusted to a resonant frequency which is one and the same relative to one another.

A hydraulic machine of the Francis-type includes: an impeller with blades; a guide vane assembly with a ring of guide vanes, a vane-free space extending between the impeller and the guide vane assembly; and at least three resonators for suppressing pressure fluctuations, the resonators respectively including a chamber and a tube connector, the tube connector being connected to the chamber, the tube connector including an end that faces away from the chamber and that opens into the vane-free space, the resonators being configured for suppressing the pressure fluctuations occurring during the operation of the hydraulic machine, the resonators being arranged at a uniform distance from each other in a circumferential direction around the impeller, and the resonators being adjusted to a resonant frequency which is one and the same relative to one another.

A hydraulic turbine includes a rotor with a runner, which is concentrically surrounded by a stator, whereby the runner comprises a plurality of runner blades arranged and distributed in a ring around a rotor axis, and each runner blade extends between a runner crown and a runner band; whereby the stator comprises a plurality of guide vanes arranged and distributed in a ring around the rotor axis, and each guide vane extends between an upper stator ring and a lower stator ring; and whereby a predetermined clearance is provided at least between the runner band and the lower stator ring. A substantial reduction of pressure pulsations in the vane-less gap between said runner blades of said runner is achieved by substantially increasing said predetermined clearance.

A hydraulic turbine includes a rotor with a runner, which is concentrically surrounded by a stator, whereby the runner comprises a plurality of runner blades arranged and distributed in a ring around a rotor axis, and each runner blade extends between a runner crown and a runner band; whereby the stator comprises a plurality of guide vanes arranged and distributed in a ring around the rotor axis, and each guide vane extends between an upper stator ring and a lower stator ring; and whereby a predetermined clearance is provided at least between the runner band and the lower stator ring. A substantial reduction of pressure pulsations in the vane-less gap between said runner blades of said runner is achieved by substantially increasing said predetermined clearance.

The double-regulated turbine comprises a spherical hub, adapted to rotate around a first rotation axis, and blades, which are each able to be swivelled relative to the hub around a second rotation axis, transversal to the first rotation axis, by respective coupling flanges that are mounted fixedly on the spherical hub and that include each an attachment surface for a corresponding blade. The attachment surface of the coupling flanges includes a flat portion.

The double-regulated turbine comprises a spherical hub, adapted to rotate around a first rotation axis, and blades, which are each able to be swivelled relative to the hub around a second rotation axis, transversal to the first rotation axis, by respective coupling flanges that are mounted fixedly on the spherical hub and that include each an attachment surface for a corresponding blade. The attachment surface of the coupling flanges includes a flat portion.

A turbine unit for a hydraulic installation, and more in particular it deals with the hub of the turbine unit. The present invention proposes to provide means for adjusting a gap extent formed between the hub and the inner edge of the blade, this way dramatically increasing the performance of the turbine.

A turbine unit for a hydraulic installation, and more in particular it deals with the hub of the turbine unit. The present invention proposes to provide means for adjusting a gap extent formed between the hub and the inner edge of the blade, this way dramatically increasing the performance of the turbine.

A method and device for determining a suction height of a variable speed unit is provided. The method includes: 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; acquiring a maximum lift, a minimum lift, 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.