Horizontally-arranged three-machine type pumped storage unit

Abstract

The utility model provides a horizontally arranged three-machine type pumped storage unit, which comprises a generator motor, a water pump and a water turbine, the generator motor, the water pump and the water turbine are horizontally arranged, a water pump shaft of the water pump is connected with a shaft of the generator motor through a coupler, and the shaft of the generator motor is connected with a shaft of the water turbine. When power generation is needed, the coupler is disconnected, the upper reservoir impacts the water turbine to generate power, and when water pumping is needed, the coupler is connected, and the water pump pumps water. The energy storage unit replaces a vertical three-unit type unit, the deep excavation volume of a plant is reduced, the construction cost of a power station is reduced, and water pumping power adjustment is facilitated.

Description

Technical Field

[0001] The utility model relates to the field of pumped storage units, in particular to a horizontally arranged three-machine pumped storage unit. Background Art

[0002] Pumped storage power stations are important flexible power sources in power grids. Mixed flow reversible units are often used, consisting of a pump-turbine and a generator motor that can operate in both directions. When the water in the power station flows from the upper reservoir to the lower reservoir through the water transmission system, the gravitational potential energy of the water is converted into kinetic energy, driving the unit to operate as a turbine to generate electricity; when the water flows from the lower reservoir to the upstream through the water transmission system, it needs to be operated as a water pump to pump water, consuming electricity to convert the kinetic energy of the water into potential energy for energy storage. However, the power of traditional reversible units cannot be adjusted when operating as water pumps, which limits the role of pumped storage power stations in new power systems. In addition, the applicable head range of this type of unit is limited. There is currently no available model at pumped storage sites with a head of more than 800m. At present, China is studying the use of variable-speed pumped storage technology to achieve pumping power regulation and improve the operational flexibility of pumped storage units. However, the rotor structure of variable-speed units is complex, and China has not yet completely conquered the technology of large-scale variable-speed pumped storage units. In addition, even if the mixed flow reversible unit has a speed change function, it still cannot solve the problem of using it in power stations above 800m.

[0003] The three-machine unit is a unit formed by connecting a water pump, a turbine and a generator motor. This type of unit was used in early pumped storage power stations, mostly using a mixed flow unit, a centrifugal pump and a generator motor combination. The three-machine pumped storage unit can be operated in a hydraulic circuit, that is, the water pump and the turbine are operated at the same time. When the pumping condition is running, the output generated by the turbine is used to compensate for the power absorbed by the pump, so that the pump condition that originally did not have the ability to adjust can achieve power adjustment to adjust the energy that the pump needs to consume from the power grid. In addition, the power generation and pumping operation modes of this type of unit have the same rotation direction, and the unit condition conversion speed is faster, which can more flexibly and quickly balance the disturbance of intermittent clean energy grid connection to the power grid. It solves the problem that the currently commonly used two-machine reversible unit cannot adjust the power during pumping operation, and is an effective means to improve the operating flexibility of the pumped storage unit and enhance the ability to serve new power systems.

[0004] Large three-machine units are generally arranged vertically. However, the height of the vertical three-machine coaxial arrangement is much higher than the existing two-machine reversible pumped storage unit (about 11m), requiring a larger plant space, greatly increasing the excavation of the power plant, and thus resulting in higher construction costs for the power plant. At present, only the Yamdrok Lake Pumped Storage Power Station in my country adopts a three-machine vertical unit structure, but the power station is restricted by environmental factors and has been mainly operated in turbine power generation conditions for many years, and the flexible operation characteristics of the three-machine unit have not been brought into play.

[0005] Mixed flow reversible pumped storage units are the most widely used, with a working head range of 30m to 800m. However, the development of mixed flow units is extremely difficult at sites with higher heads and greater energy density.

[0006] Traditional three-machine units (such as the Yangzhuoyong Lake Pumped Storage Power Station) adopt a vertical layout. The generator motor, turbine, and water pump are connected by 5 shafts, namely the generator motor shaft, turbine shaft, upper intermediate shaft, lower intermediate shaft, and pump shaft. The first 4 shafts are rigidly connected, and the last two shafts are connected by gear couplings. The axis is as long as 23m, with poor stability, and it is difficult to control the axis during installation. The entire unit has two thrust bearings, namely the suspended generator motor thrust bearing and the energy storage pump thrust bearing. It is difficult to adjust the two thrust bearings horizontally and uniformly. Due to the long axis of the unit, the unit is equipped with 6 guide bearings, namely the upper and lower guide bearings of the generator motor, the turbine guide bearing, the intermediate guide bearing, and the upper and lower guide bearings of the water pump. There are as many as 5 rigid flange connections between the shafts, and the manufacturing and installation errors are accumulated, which is not conducive to the swing control. In general, the unit has a complex structure and poor operating stability.

[0007] The investment in a vertical three-machine unit is high, not only because the three-machine scheme has one more hydraulic machine than the two-machine reversible scheme, but also because the existing units require separate volutes, tailwater pipes and water inlet valves for both the pump and the turbine; and in order to make the unit rotate in the same direction when the pump and turbine are working, the turbine and pump volutes need to turn in opposite directions, causing the unit's plane width to increase, resulting in increased investment in mechanical equipment and civil engineering. Summary of the invention

[0008] The technical problem to be solved by the utility model is to provide a horizontally arranged three-machine pumped storage unit to replace the vertical three-machine unit, reduce the depth of plant excavation, reduce the construction cost of the power station, and facilitate the adjustment of pumping power.

[0009] In order to solve the above technical problems, the technical solution adopted by the utility model is: a horizontally arranged three-machine pumped storage unit, including a generator motor, a water pump and a turbine, the generator motor, the water pump and the turbine are arranged horizontally, the pump shaft of the water pump is connected to the shaft of the generator motor through a coupling, the shaft of the generator motor is connected to the turbine shaft, and guide bearings supporting the water pump shaft and the turbine shaft are provided at both ends of the generator motor. When power generation is required, the coupling is disconnected, and the upper reservoir impacts the turbine to generate electricity. When pumping is required, the coupling is connected and the water pump is used to pump water.

[0010] In a preferred embodiment, the water turbine is an impulse water turbine.

[0011] In a preferred solution, the shaft of the generator motor and the turbine shaft are the same shaft.

[0012] In a preferred embodiment, the water inlet of the water pump is connected to the lower reservoir through an inlet pipe, the water outlet of the water pump is connected to the main pipe and the impact pipe respectively through the outlet pipe, the main pipe is connected to the upper reservoir, the impact pipe is connected to the water guiding mechanism of the turbine, the return water tank of the turbine is connected to the lower reservoir through a pipe, and the outlet pipe and the impact pipe are respectively provided with a first valve and a second valve.

[0013] The utility model provides a horizontally arranged three-machine pumped storage unit, which has the following beneficial effects:

[0014] 1. For the traditional vertical arrangement of three-machine units, the axial height of the power station is large, the excavation of the plant is large, and the construction cost is high. The horizontal arrangement of three-machine pumped storage units reduces the longitudinal excavation of the plant, which can greatly reduce the project investment for the plant on the ground or semi-underground, has better economy and stability, and reduces the construction cost of the power station.

[0015] 2. Simplify the shaft system structure of the three-machine pumped storage unit, improve the speed of shaft system installation and alignment of the power station, and solve the shaft system stability problem of the existing power station.

[0016] 3. For pumped storage sites with a water head higher than 800m, it is difficult to develop traditional mixed flow reversible pumped storage units. The three-machine pumped storage unit using impulse turbines can adapt to the water head range of 800m~2000m, meeting the demand for the use of high-head pumped storage units in my country's pumped storage development plan. The use of impulse turbines increases the application head of the pumped storage unit.

[0017] 4. At present, all pumped-storage power stations that have been put into operation in China use fixed-speed mixed-flow reversible units, which have the problem that the power cannot be adjusted under pumping conditions, limiting the flexible adjustment function of pumped storage. The three-machine unit of the utility model can adjust the power under pumping and power generation conditions according to the needs of the power grid. When the power is adjusted under pumping conditions, the turbine and the water pump are both in operation. The problem that the power cannot be adjusted under pumping conditions can be solved by adjusting the power of the turbine, which can enhance the ability of the pumped-storage power station to flexibly adjust the service power grid.

[0018] 5. The existing pumped storage units are mainly started by compressing water with compressed air. This technical solution can directly start the pumping condition by running three units simultaneously, eliminating the compressed air system compared to the existing pumped storage power stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0020] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0021] Figure 2This is a schematic diagram of water flow when the hydraulic circuit of the utility model is in operation;

[0022] In the figure: a generator motor 1, a water pump 2, a turbine 3, a coupling 4, a guide bearing 5, an upper reservoir 6, a lower reservoir 7, an inlet pipe 8, an outlet pipe 9, a main pipe 10, an impact pipe 11, a first valve 12, and a second valve 13. DETAILED DESCRIPTION

[0023] Embodiment 1:

[0024] like Figure 1 As shown, a horizontally arranged three-machine pumped storage unit includes a generator motor 1, a water pump 2 and a turbine 3. The generator motor 1, the water pump 2 and the turbine 3 are arranged horizontally, and the water pump 2 and the turbine 3 are arranged at both ends of the generator motor 1. The turbine 3 is a bucket-type impulse turbine that can operate at a head of more than 800m. The turbine can use 1, 2, 3 or 6 nozzles as needed, and the water pump can use a variety of types such as single-pole, multi-stage or double-suction according to the head.

[0025] Existing horizontal mixed flow turbine generators usually generate a large axial thrust on the main shaft, and a thrust bearing needs to be provided to offset the axial thrust generated by the turbine on the main shaft. In this embodiment, a horizontal Pelton type impulse turbine is used, which has no axial water thrust and does not need to be installed with a thrust bearing. Instead, only a guide bearing needs to be installed, which reduces the volume of the entire power generation equipment.

[0026] The water pump shaft of the water pump 2 is connected to the shaft of the generator motor 1 through a coupling 4, and the shaft of the generator motor 1 is connected to the turbine shaft. Guide bearings 5 ​​supporting the water pump shaft and the turbine shaft are provided at both ends of the generator motor 1 to withstand the radial and electromagnetic unbalanced forces of the rotating part of the unit.

[0027] The shaft system can be composed of three sections or two sections. The three sections include the water pump shaft, the generator motor shaft, and the turbine shaft. In the two-section shaft scheme, the turbine and the generator motor can use one shaft.

[0028] There are two working conditions involved. When power generation is needed, that is, in the power generation condition, the coupling 4 is disconnected, and the upper reservoir 6 impacts the turbine 3 to generate power. The impulse turbine only drags the generator motor to generate electricity. When the pumping condition is in operation, the coupling 4 is connected, the water pump 2 pumps water, and the water pump 2 runs together with the generator motor 1 and the turbine 3.

[0029] Embodiment 2:

[0030] Different from Example 1, Figure 2As shown, the water inlet of the water pump 2 is connected to the lower reservoir 7 through the water inlet pipe 8, and the water outlet of the water pump 2 is connected to the main pipe 10 and the impact pipe 11 through the outlet pipe 9, the main pipe 10 is connected to the upper reservoir 6, the impact pipe 11 is connected to the water guide mechanism of the turbine 3, and the turbine 3 is connected to the lower reservoir 7. The first valve 12 and the second valve 13 are respectively provided on the outlet pipe 9 and the impact pipe 11, and the first valve 12 and the second valve 13 are ball valves.

[0031] When the pumped storage power station needs to generate power, the second valve 13 in front of the impulse turbine is opened, and the runner is impacted by the water flow to rotate, driving the generator motor 1 to rotate and generate electricity. At this time, the coupling 4 is disconnected, and the water pump 2 is separated from the generator motor 1. The impulse turbine operates within its power adjustment range by adjusting the nozzle flow.

[0032] When the pumped storage power station unit needs to pump water to absorb power, the first valve 12 upstream of the water pump 2 is fully opened, and the generator motor 1 drives the water pump 2 to rotate, consuming a fixed power value P to pump water.

[0033] When the unit needs to adjust the power during pumping operation, it operates in a hydraulic circuit mode. The specific method is: the water pump 2 and the turbine 3 operate at the same time, the first valve 12 upstream of the water pump 2 is fully opened, and the second valve 13 is opened to a certain degree according to the power demand, and the power output power Pt can be adjusted within the allowable operating range. The water pumping power is P, and then the power of the entire three-machine unit can also be adjusted within the range of the water pump power P~(P-Pt).

Claims

1. A horizontally arranged three-machine pumped storage unit, comprising a generator motor (1), a water pump (2) and a water turbine (3), characterized in that: The generator motor (1), water pump (2) and water turbine (3) are arranged horizontally. The water pump shaft of the water pump (2) is connected to the machine shaft of the generator motor (1) via a coupling (4). The machine shaft of the generator motor (1) is connected to the water turbine shaft. Guide bearings (5) for supporting the water pump shaft and the water turbine shaft are provided at both ends of the generator motor (1). When power generation is required, the coupling (4) is disconnected, and the upper reservoir (6) impacts the water turbine (3) to generate power. When water pumping is required, the coupling (4) is connected, and the water pump (2) pumps water.

2. A horizontally arranged three-machine pumped storage unit according to claim 1, characterized in that: The water turbine (3) is an impulse water turbine.

3. The horizontally arranged three-machine pumped storage unit according to claim 1, characterized in that: The shaft of the generator motor (1) and the turbine shaft are the same shaft.

4. The horizontally arranged three-machine pumped storage unit according to claim 1, characterized in that: The water inlet of the water pump (2) is connected to the lower reservoir (7) via a water inlet pipe (8), and the water outlet of the water pump (2) is respectively connected to a main pipe (10) and an impact pipe (11) via a water outlet pipe (9); the main pipe (10) is connected to the upper reservoir (6), the impact pipe (11) is connected to the water guide mechanism of the turbine (3), and the turbine (3) is connected to the lower reservoir (7); the water outlet pipe (9) and the impact pipe (11) are respectively provided with a first valve (12) and a second valve (13).

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