A three-level reservoir pumped storage system utilizing underground mine space

Abstract

A three-level reservoir pumped storage system that utilizes underground mine space includes a high-level reservoir, a middle-level reservoir, and a low-level reservoir. The drainage side of the middle-level reservoir is connected to the high-level reservoir via a middle-high-level booster water pump, and the drainage side of the low-level reservoir is connected to the high-level reservoir via a low-high-level booster water pump, and a low-middle-level booster water pump is provided between the low-level reservoir and the middle-level reservoir. In addition, the water in the high-level reservoir is discharged to the low-level reservoir after the low-back-pressure hydro-generator set performs work, and the water in the high-level reservoir is discharged to the middle-level reservoir after the high-back-pressure hydro-generator set performs work. The present invention utilizes three water storage spaces, high, medium, and low, and realizes the flexible conversion of water's gravitational potential energy and electrical energy through the transfer of water in the three water storage spaces, thereby achieving the function of flexible regulation of energy storage. It is suitable for pumped storage in reservoirs with dams, as well as for underground mines and tunnels that serve as water storage and pumped storage spaces.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system energy storage, and in particular to a three-level reservoir pumped storage system utilizing underground mine space. Background Art

[0002] Currently, the "promoting the development of energy storage technology and industry" is strongly boosting market confidence as the technical support and industrial guarantee for my country's transformation from an energy powerhouse to an energy superpower and improving economic quality and efficiency. With the advancement of carbon peak and carbon neutrality, the shift in energy structure from fossil fuels to renewable energy is accelerating. Therefore, it is necessary to achieve the localization of large-capacity energy storage equipment to address the bottleneck of renewable energy grid connection. Summary of the Invention

[0003] The purpose of the present invention is to provide a three-level reservoir pumped storage system that utilizes underground mine space, which can fully and extensively utilize the underground tunnel space of abandoned coal mines, abandoned metal mines, etc. with large height differences between the ground and the ground to realize pumped storage, greatly expanding the utilization places of pumped storage.

[0004] The technical solution of the present invention is specifically as follows:

[0005] A three-level reservoir pumped storage system that utilizes underground mine space is provided with three water storage spaces of high, medium and low levels. The water in the three water storage spaces is connected through a booster pump, a turbine generator set and related pipeline valves to convert the gravitational potential energy of the water into electrical energy, thereby realizing a two-level pumped storage function. Specifically, it includes a high-level reservoir, a middle-level reservoir and a low-level reservoir. Among them, the drainage side of the middle-level reservoir is connected to the high-level reservoir through a middle-high-level booster water pump, and the drainage side of the low-level reservoir is connected to the high-level reservoir through a low-high-level booster water pump, and a low-middle-level booster water pump is provided between the low-level reservoir and the middle reservoir. In addition, the water in the high-level reservoir is discharged to the low-level reservoir after the low-back-pressure turbine generator set performs work, and the water in the high-level reservoir is discharged to the middle-level reservoir after the high-back-pressure turbine generator set performs work.

[0006] The drainage side of the middle-level reservoir is connected to the high-level reservoir in sequence through the middle-high-level booster water pump inlet valve, middle-high-level booster water pump, middle-high-level booster water pump outlet valve, and high-level reservoir water storage valve, thus forming a middle-high-level reservoir energy storage system;

[0007] The drainage side of the low-level reservoir is connected to the high-level reservoir through the low-level reservoir outlet valve, the low- and high-level booster water pump inlet valve, the low- and high-level booster water pump, the low- and high-level booster water pump outlet valve, and the high-level reservoir water storage valve in sequence, thus forming a low- and high-level reservoir energy storage system.

[0008] A pipeline is set before the low-high-pressure boost water pump inlet valve at the low-high-pressure boost water pump inlet, the pipeline is connected to the mid-level reservoir, and a first shut-off valve is set on the pipeline.

[0009] The drainage side of the low-level reservoir is connected to the middle-level reservoir through the low-level booster water pump inlet valve, low-level booster water pump, and low-level booster water pump outlet valve in sequence, thus forming a low-level reservoir energy storage system to lift the water from the low-level reservoir to the middle-level reservoir.

[0010] The water from the high-level reservoir flows into the low-level reservoir in sequence through the high-level reservoir outlet valve, the low-back-pressure turbine generator set inlet valve, the low-back-pressure turbine generator set, and the low-back-pressure turbine generator set outlet valve, thus forming a high- and low-level reservoir water discharge and energy generation system.

[0011] The water from the high-level reservoir enters the middle-level reservoir through the high back-pressure turbine generator set inlet valve, the high back-pressure turbine generator set inlet valve, and the middle-level reservoir water storage valve in turn, thus forming a high- and medium-level reservoir water discharge and energy release power generation system.

[0012] A high-level excess pressure hydro-turbine generator set is arranged behind the medium-high-level booster water pumps and the low-high-level booster water pumps and in front of the high-level reservoir. An inlet shut-off valve and an outlet shut-off valve are respectively arranged at the inlet and outlet of the high-level excess pressure hydro-turbine generator set; a bypass valve is arranged on the bypass of the inlet and outlet pipelines of the high-level excess pressure hydro-turbine generator set.

[0013] The high-pressure residual-pressure turbine generator set is arranged at the high-level reservoir elevation, and the medium-high-level booster water pump, low-high-level booster water pump, low-medium-level booster water pump, low back-pressure turbine generator set, and high back-pressure turbine generator set are arranged at the low-level reservoir elevation.

[0014] An overflow pipeline is set up in the high-level reservoir, and a high-level reservoir overflow valve is set up on the overflow pipeline.

[0015] A pipeline is set behind the high back-pressure hydro-generator set to connect to the low-level reservoir, and a second shut-off valve is set on the pipeline.

[0016] The beneficial effects of this invention are as follows: it utilizes three water storage spaces (high, medium, and low) to achieve flexible conversion of water's gravitational potential energy and electrical energy through the transfer of water between the three storage spaces, thus achieving flexible regulation of energy storage. This system is suitable for pumped storage in dammed reservoirs as well as underground mines and tunnels. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the present invention. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0020] like Figure 1 As shown, a three-stage reservoir pumped storage system utilizing underground mine space is provided with three water storage spaces at high, medium and low levels. The water in the three water storage spaces is connected through a booster pump, a hydro-generator set and related pipeline valves to convert the gravitational potential energy of the water into electrical energy, thus realizing a two-stage pumped storage function.

[0021] Specifically, it includes a high-level reservoir 1, a middle-level reservoir 2 and a low-level reservoir 3, wherein the drainage side of the middle-level reservoir 2 is connected to the high-level reservoir 1 through a middle-high-level booster water pump 4, and the drainage side of the low-level reservoir 3 is connected to the high-level reservoir 1 through a low-high-level booster water pump 5, and a low-middle-level booster water pump 6 is arranged between the low-level reservoir 3 and the middle-level reservoir 2; in addition, the water in the high-level reservoir 1 is discharged to the low-level reservoir 3 after the low back-pressure turbine generator set 8 does work, and the water in the high-level reservoir 1 is discharged to the middle-level reservoir 2 after the high back-pressure turbine generator set 9 does work.

[0022] Furthermore, the drainage side of the middle-level reservoir 2 is connected to the high-level reservoir 1 in sequence through the middle-high-level booster water pump inlet valve 10, the middle-high-level booster water pump 4, the middle-high-level booster water pump outlet valve 11, and the high-level reservoir water storage valve 12, thereby forming a middle-high-level reservoir energy storage system.

[0023] Furthermore, the drainage side of the low-level reservoir 3 is connected to the high-level reservoir 1 through the low-level reservoir outlet valve 24, the low- and high-level booster water pump inlet valve 17, the low- and high-level booster water pump 5, the low- and high-level booster water pump outlet valve 18, and the high-level reservoir water storage valve 12 in sequence, thereby forming a low- and high-level reservoir energy storage system.

[0024] Furthermore, a pipeline is arranged before the low-high-pressure boost water pump inlet valve 17 at the inlet of the low-high-pressure boost water pump 5, the pipeline is connected to the mid-level reservoir 2, and a first shut-off valve 16 is arranged on the pipeline, so that the water in the mid-level reservoir 2 can be lifted to the high-level reservoir 1 through the low-high-pressure boost water pump 5.

[0025] In this way, during the energy storage stage, the water in the middle reservoir 2 is lifted to the high reservoir 1 through the middle and high-level booster water pump 4, and the water in the low reservoir 3 is also lifted to the high-pressure reservoir 1 through the low and high-level booster water pump 5, converting electrical energy into the gravitational potential energy of water to form a pumped storage system.

[0026] Furthermore, the drainage side of the low-level reservoir 3 is connected to the middle-level reservoir 2 in sequence through the low-high-level booster water pump inlet valve 25, the low-middle-level booster water pump 6, and the low-high-level booster water pump outlet valve 26, thereby forming a low-middle-level reservoir energy storage system, which can lift the water from the low-level reservoir 3 to the middle-level reservoir 2 and ensure the water level of the low-level reservoir to improve the efficiency of the low back-pressure hydro-generator set.

[0027] During the energy release stage, the water in the high-level reservoir 1 is discharged to the low-level reservoir 3 after the low-back-pressure hydro-generator set 8 performs work. Alternatively, the water in the high-level reservoir 1 is discharged to the middle-level reservoir 2 after the high-back-pressure hydro-generator set 9 performs work, and the gravitational potential energy of the water is converted into electrical energy to form a water discharge power generation system.

[0028] Furthermore, the water from the high-level reservoir 1 enters the low-level reservoir 3 in sequence through the high-level reservoir water storage valve 12, the low back-pressure hydro-generator set inlet valve 19, the low back-pressure hydro-generator set 8, and the low back-pressure hydro-generator set outlet valve 20, thereby forming a high- and low-level reservoir water discharge and energy release power generation system.

[0029] Furthermore, the water in the high-level reservoir 1 enters the middle-level reservoir 2 in sequence through the high back-pressure hydro-generator set inlet valve 21, the high back-pressure hydro-generator set 9, and the middle-level reservoir water storage valve 23, thereby forming a high- and medium-level reservoir water discharge and energy release power generation system.

[0030] Furthermore, a high-level excess pressure hydro-turbine generator set 7 is provided after the medium-high-level booster pump 4 and the low-high-level booster pump 5, and in front of the high-level reservoir 1, for recovering the excess pressure of the water entering the high-level reservoir 1 when the booster pump inlet pressure is relatively high. An inlet shut-off valve 13 and an outlet shut-off valve 14 are provided at the inlet and outlet of the high-level excess pressure hydro-turbine generator set 7, respectively. More preferably, a bypass valve 15 is provided on the bypass of the inlet and outlet pipes of the high-level excess pressure hydro-turbine generator set 7. In this way, the inlet shut-off valve 13, the high-level excess pressure hydro-turbine generator set 7, the outlet shut-off valve 14, the bypass valve 15, and the high-level reservoir 1 constitute an excess pressure recovery system. During the water storage stage, when the water pressure discharged into the high-level reservoir 1 is relatively high, the pressurized water is first passed through the high-level excess pressure hydro-turbine generator set 7 to perform work to recover the excess pressure energy before being discharged into the high-level reservoir 1, thereby reducing energy waste. When the inlet pressure of the medium-high-pressure boost water pump 4 and the low-high-pressure boost water pump 5 is low and insufficient to drive the high-pressure residual pressure hydro-turbine generator set 7, the inlet shut-off valve 13 and the outlet shut-off valve 14 of the high-pressure residual pressure hydro-turbine generator set 7 are closed, and the bypass valve 15 is opened at the same time, so that the water at the outlet of the boost pump is directly discharged into the high-pressure reservoir 1.

[0031] Furthermore, the high-level excess pressure hydro-turbine generator set 7 is arranged at the elevation of the high-level reservoir 1, and the medium-high-level booster water pump 4, the low-high-level booster water pump 5, the low-medium-level booster water pump 6, the low back-pressure hydro-turbine generator set 8, and the high back-pressure hydro-turbine generator set 9 are arranged at the elevation of the low-level reservoir 3.

[0032] Furthermore, the high-level reservoir 1 is provided with an overflow pipeline, and a high-level reservoir overflow valve 27 is provided on the overflow pipeline. When the water level of the high-level reservoir 1 reaches a high water level, the water overflows into a nearby ditch.

[0033] Furthermore, a pipeline is set behind the high back pressure hydro-generator set 9 to connect to the low-level reservoir 3, and a second shut-off valve 22 is set on the pipeline, so that when needed, the water in the high-level reservoir 1 can be directly discharged into the low-level reservoir 3 after the high back pressure hydro-generator set 9 does work.

[0034] Furthermore, the high back-pressure turbine generator set 9 and the medium-high pressure booster pump 4 can be combined into a pumped storage integrated high back-pressure pump turbine device, and the inlet and outlet valves and pipelines can be combined accordingly to save investment and improve system efficiency.

[0035] Implementation examples: The following lists some specific embodiments of the power storage and power generation stages of this system. The described embodiments are part of the embodiments of the present invention, but not all of the embodiments.

[0036] Power storage stage:

[0037] Example 1: When there is surplus electricity in the external power grid and electricity needs to be stored, open the low-level reservoir outlet valve 24, the low- and high-level booster water pump inlet valve 17, the low- and high-level booster water pump outlet valve 18, and the bypass valve 15, and lift the water in the low-level reservoir 3 to the high-level reservoir 1 through the low- and high-level booster water pump 5, realizing the conversion of electrical energy into the gravitational potential energy of water, thereby achieving the effect of storing electrical energy.

[0038] Example 2: When the external power grid has excess electricity and requires power storage, the inlet valve 10 and outlet valve 11 of the mid-high-pressure booster pump are opened, and the water in the mid-level reservoir 2 is pressurized by the mid-high-pressure booster pump 4. When the drainage pressure is high, the inlet shut-off valve 13 and outlet shut-off valve 14 are opened to recover the residual pressure energy before draining the water into the high-level reservoir 1. When the drainage pressure is low, the inlet shut-off valve 13 and outlet shut-off valve 14 are closed, and the bypass valve 15 is opened to drain the water directly into the high-level reservoir 1. If the water level in the high-level reservoir 1 exceeds the high-high water level limit, the high-level reservoir overflow valve 27 is opened to overflow the excess water into a nearby ditch to protect the safety of the high-level reservoir. The entire process converts electrical energy into the gravitational potential energy of water, achieving the effect of storing electrical energy.

[0039] Power generation stage

[0040] Example 1: During peak external electricity demand, the high-level reservoir water storage valve 12, the low-back-pressure turbine generator set inlet valve 19, and the low-back-pressure turbine generator set outlet valve 20 are opened. Water from the high-level reservoir 1 is generated by the low-back-pressure turbine generator set 8, converting the water's gravitational potential energy into electrical energy. To maintain a stable backpressure of the low-back-pressure turbine generator set 8 and the efficiency of the turbine, when the water level in the low-level reservoir 3 is high, the low-high-pressure booster pump inlet valve 25 and the low-high-pressure booster pump outlet valve 26 are opened, allowing water from the low-level reservoir to be discharged into the middle-level reservoir 2 via the low-mid-pressure booster pump 6.

[0041] Example 2: During the peak period of external electricity consumption, the high back pressure turbine generator set inlet valve 21 and the mid-level reservoir water storage valve 23 are opened to allow the water in the high-level reservoir 1 to pass through the high back pressure turbine generator set 9 to generate power, thereby converting the gravitational potential energy of the water into electrical energy.

[0042] The energy storage system in this invention incorporates three pumping storage modes: pumping water from a mid-level reservoir to a high-level reservoir, from a low-level reservoir to a high-level reservoir, and from a low-level reservoir to a mid-level reservoir. A booster pump is installed between any two reservoirs, and shutoff valves are installed at both the inlet and outlet of the booster pump, enabling multiple water pumping modes. This significantly enhances the flexibility of energy storage.

[0043] The energy release system in this invention includes two modes: discharging water from the high-level reservoir to the low-level reservoir, and discharging water from the high-level reservoir to the low-level reservoir. A high-back-pressure turbine generator set is installed between the high and low reservoirs, and a low-back-pressure turbine generator set is installed between the high and low reservoirs. The turbine generator sets convert the gravitational potential energy of the high-level reservoir water into electrical energy through the work of the turbine generator sets, realizing the energy release process of the water storage system. Shutoff valves are installed at the inlet and outlet of each turbine generator set.

[0044] The present invention employs a residual pressure recovery system installed at the same level as the elevated reservoir. During the energy storage phase, when the booster pump discharge pressure is high, the booster pump discharge is first directed to the elevated residual pressure turbine generator set to recover the residual pressure potential energy, preventing the loss of pressure energy caused by direct discharge of pressurized water into the elevated reservoir. When the booster pump discharge pressure drops below the residual pressure required to propel the turbine generator set, the discharge bypasses the elevated residual pressure turbine generator set and is discharged directly into the elevated reservoir.

[0045] The overflow system of the present invention is set at the high water level of the high reservoir. When the water level of the high reservoir exceeds the high water level line, the valve on the overflow pipe opens to overflow the water into the ditch to ensure the safety of the high reservoir.

[0046] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several changes and improvements can be made without departing from the overall concept of the present invention, and these should also be regarded as the scope of protection of the present invention.

Claims

1. A three-stage reservoir pumped storage system utilizing underground mine space, characterized by: Three water storage spaces, high, medium and low, are provided. The water in the three water storage spaces is connected through a booster pump, a turbine generator set and related pipeline valves, so that the gravitational potential energy of the water is converted into electrical energy, thereby realizing a two-stage pumped storage function. Specifically, the high-level reservoir (1), the middle-level reservoir (2) and the low-level reservoir (3) are provided. The drainage side of the middle-level reservoir (2) is connected to the high-level reservoir (1) through a middle-high-level booster water pump (4), and the drainage side of the low-level reservoir (3) is connected to the high-level reservoir (1) through a low-high-level booster water pump (5). A low-medium-level booster water pump (6) is provided between the low-level reservoir (3) and the middle-level reservoir (2). In addition, the water in the high-level reservoir (1) is discharged to the low-level reservoir (3) after the low-back-pressure turbine generator set (8) performs work, and the water in the high-level reservoir (1) is discharged to the middle-level reservoir (2) after the high-back-pressure turbine generator set (9) performs work. The drainage side of the middle-level reservoir (2) is connected to the high-level reservoir (1) in sequence through the middle-high-level booster water pump inlet valve (10), the middle-high-level booster water pump (4), the middle-high-level booster water pump outlet valve (11), and the high-level reservoir water storage valve (12), thereby forming a middle-high-level reservoir energy storage system; The drainage side of the low-level reservoir (3) is connected to the high-level reservoir (1) in sequence through the low-level reservoir outlet valve (24), the low- and high-level booster water pump inlet valve (17), the low- and high-level booster water pump (5), the low- and high-level booster water pump outlet valve (18), and the high-level reservoir water storage valve (12), thereby forming a low- and high-level reservoir energy storage system; A pipeline is provided before the low- and high-pressure boost water pump inlet valve (17) at the inlet of the low- and high-pressure boost water pump (5), the pipeline being connected to the mid-level reservoir (2), and a first shut-off valve (16) is provided on the pipeline.

2. The three-level reservoir pumped storage system utilizing underground mine space according to claim 1 is characterized in that: The drainage side of the low-level reservoir (3) is connected to the middle-level reservoir (2) through the low- and high-level booster water pump inlet valve (25), the low- and middle-level booster water pump (6), and the low- and high-level booster water pump outlet valve (26) in sequence, thereby forming a low- and middle-level reservoir energy storage system to lift the water in the low-level reservoir (3) to the middle-level reservoir (2).

3. The three-level reservoir pumped storage system utilizing underground mine space according to claim 1 is characterized in that: The water in the high-level reservoir (1) enters the low-level reservoir (3) in sequence through the high-level reservoir water storage valve (12), the low-back-pressure hydro-generator set inlet valve (19), the low-back-pressure hydro-generator set (8), and the low-back-pressure hydro-generator set outlet valve (20), thereby forming a high- and low-level reservoir water discharge energy release power generation system; The water in the high-level reservoir (1) enters the middle-level reservoir (2) in sequence through the high-back-pressure hydro-generator inlet valve (21), the high-back-pressure hydro-generator (9), and the middle-level reservoir water storage valve (23), thereby forming a high- and medium-level reservoir water discharge and energy release power generation system.

4. The three-level reservoir pumped storage system utilizing underground mine space according to claim 1 is characterized in that: A high-pressure turbine generator set (7) is provided after the middle-high-pressure booster pump (4) and the low-high-pressure booster pump (5) and in front of the high-pressure reservoir (1). An inlet shut-off valve (13) and an outlet shut-off valve (14) are provided at the inlet and outlet of the high-pressure turbine generator set (7), respectively. A bypass valve (15) is provided on the bypass of the inlet and outlet pipelines of the high-pressure turbine generator set (7).

5. The three-level reservoir pumped storage system utilizing underground mine space according to claim 1 is characterized in that: The high-pressure residual-pressure turbine generator set (7) is arranged at the elevation of the high-level reservoir (1), and the medium-high-level booster water pump (4), the low-high-level booster water pump (5), the low-medium-level booster water pump (6), the low-back-pressure turbine generator set (8), and the high-back-pressure turbine generator set (9) are arranged at the elevation of the low-level reservoir (3).

6. The three-level reservoir pumped storage system utilizing underground mine space according to claim 1 is characterized in that: The high-level reservoir (1) is provided with an overflow pipeline, and a high-level reservoir overflow valve (27) is provided on the overflow pipeline.

7. The three-level reservoir pumped storage system utilizing underground mine space according to claim 1 is characterized in that: A pipeline is provided behind the high back-pressure hydro-generator set (9) to connect to the low-level reservoir (3), and a second shut-off valve (22) is provided on the pipeline.

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