Abstract: 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.

Abstract: The present invention discloses a differential COTDR distributed acoustic sensing device based on heterogeneous double-sideband chirped-pulses of the invention, comprising a light source (1), a 1×2 polarization-maintaining optical-fiber coupler (2), a dual Mach-Zehnder electro-optical modulator (3), an arbitrary waveform generator (4), a first low noise microwave amplifier (5), a second low noise microwave amplifier (6), an electro-optical modulator bias control panel (7), a 1×2 optical-fiber coupler (8), an erbium-doped optical-fiber amplifier (9), an optical-fiber filter (10), an optical-fiber circulator (11), a sensing optical fiber (12), a tricyclic polarization controller (13), a 2×2 optical-fiber coupler (14), a balanced photoelectric detector (15), a data acquisition card (16) and a processing unit (17).

Abstract: A method for determining a regulation range of pumping power of a three-machine pumped storage unit is provided. The method includes: obtaining a first parameter set of pumping measurement parameters for characterizing the three-machine pumped storage unit and determining a pumping process efficiency; determining a first relational expression based on the pumping process efficiency and a design efficiency of a pumped storage power station and establishing a second relational expression; and determining a third relational expression based on power absorbed by a power grid and the second relational expression and determining a fourth relational expression, where the fourth relational expression reflects the regulation range of the pumping power of the three-machine pumped storage unit. The method for determining the regulation range of the pumping power of the three-machine pumped storage unit is proposed according to unit characteristics and operating economy of the power station.

Abstract: 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.

Abstract: The present invention discloses a differential COTDR distributed acoustic sensing device based on heterogeneous double-sideband chirped-pulses of the invention, comprising a light source (1), a 1×2 polarization-maintaining optical-fiber coupler (2), a dual Mach-Zehnder electro-optical modulator (3), an arbitrary waveform generator (4), a first low noise microwave amplifier (5), a second low noise microwave amplifier (6), an electro-optical modulator bias control panel (7), a 1×2 optical-fiber coupler (8), an erbium-doped optical-fiber amplifier (9), an optical-fiber filter (10), an optical-fiber circulator (11), a sensing optical fiber (12), a tricyclic polarization controller (13), a 2×2 optical-fiber coupler (14), a balanced photoelectric detector (15), a data acquisition card (16) and a processing unit (17).

Abstract: A very large floating structure based on modular units and a combined mooring system. The system includes a central large platform module, small outer platform modules, tension-legs, mooring lines, oscillating float-type wave energy converters and module connectors. The oscillating float-type wave energy converters can convert the swinging motion of the floaters into the horizontal motion of the piston rods through the gear wheel-rack transmission. Module connectors between modules are divided into two kinds of modes. One can utilize both relative torsional motion and horizontal motion between the central large platform module and the adjacent small platform modules, while the other simultaneously generates power and reduces the relative motions between the adjacent platform modules. The wave energy converters on the outer modules of the very large floating structure can generate power by absorbing the incident wave energy.