A shaft-type gravity energy storage system and its operation and design method

Abstract

The present invention discloses a shaft-type gravity energy storage system and its operation and design method, wherein the system structure includes at least two sets of gravity turbine systems; in each set of gravity turbine systems, a first gravity turbine sky wheel, a second gravity turbine sky wheel and a gravity turbine friction wheel are included, the first gravity turbine sky wheel and the second gravity turbine sky wheel are both arranged on the derrick, the gravity turbine friction wheel is connected to the electric generator integrated machine, a braking device is arranged at the gravity turbine friction wheel, a steel wire rope is connected to the first gravity turbine sky wheel, the second gravity turbine sky wheel and the gravity turbine friction wheel for transmission, two ends of the steel wire rope are respectively connected to two lifting containers, the lower ends of the two lifting containers are connected to equal weight tail ropes, when one of the two lifting containers is located at the wellhead platform of the upper warehouse, the other of the two lifting containers is located at the well bottom platform of the lower warehouse. This scheme can achieve the goals of high conversion efficiency, continuous discharge, low economic cost and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of gravity energy storage power generation, and specifically relates to a vertical shaft type gravity energy storage system and an operation and design method thereof. Background Art

[0002] The gravity energy storage system mainly consists of two parts: energy storage and discharge. When storing energy, the heavy blocks are lifted from a low place (lower warehouse) to a high place (upper warehouse) for storage, and the electrical energy is finally converted into gravitational potential energy; when discharging, the heavy blocks are lowered from a high place (upper warehouse) to a low place (lower warehouse), and the gravitational potential energy is first converted into kinetic energy, which is then driven by the transmission device to generate electricity, and finally converted into electrical energy. As a new energy storage technology, gravity energy storage has no engineering cases put into operation in China. At present, the first structure-type gravity energy storage project in China is under construction. As a commercial and engineered power project, the success of the gravity energy storage project depends on whether it can provide continuous and stable current, which depends on the weight of the lifting heavy blocks and the stability of the speed. The shaft-type gravity energy storage system is a gravity energy storage based on the shaft, which uses the height difference between the upper and lower parts of the shaft as a transportation channel for the energy storage heavy blocks. Relevant existing patents include the Chinese invention patent with application publication number CN113914865A, but the existing patent solutions still have some shortcomings. For example, the heavy blocks can only be lifted and lowered individually, resulting in low utilization efficiency of the overall lifting equipment, and continuous discharge cannot be achieved, and the conditions for commercial application are not met. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a shaft-type gravity energy storage system and its operation and design methods, so as to solve the problems of low efficiency of existing solutions, especially for large-capacity and long-term energy storage, to achieve goals such as ultra-large lifting height, ultra-heavy energy density, and ultra-large single-unit capacity, and to achieve high conversion efficiency, continuous discharge, low economic cost, long service life, high safety factor and other use effects.

[0004] According to the technical solution of the present invention, the present invention provides a shaft-type gravity energy storage system, including a shaft, an upper warehouse is provided at the upper part of the shaft, and a lower warehouse is provided at the lower part of the shaft; the upper warehouse has an upper warehouse conveying and loading and unloading system, and the lower warehouse has a lower warehouse conveying and loading and unloading system; a derrick is provided above the shaft; a tankway and a lifting container are provided in the shaft, and the lifting container can move up and down along the tankway between the wellhead platform of the upper warehouse and the well bottom platform of the lower warehouse;

[0005] It also includes a gravity turbine system; in a set of gravity turbine system, it includes a first gravity turbine sheave, a second gravity turbine sheave and a gravity turbine friction wheel, the first gravity turbine sheave and the second gravity turbine sheave are both arranged on the derrick, the gravity turbine friction wheel is connected to the electric generator, a braking device is provided at the gravity turbine friction wheel, a steel wire rope is connected to the first gravity turbine sheave, the second gravity turbine sheave and the gravity turbine friction wheel for transmission, the two ends of the steel wire rope are respectively connected to two lifting containers, the lower ends of the two lifting containers are connected to equal weight tail ropes, when one of the two lifting containers is located at the wellhead platform of the upper warehouse, the other of the two lifting containers is located at the well bottom platform of the lower warehouse.

[0006] Furthermore, in one vertical shaft, lifting containers of at least two sets of gravity turbine systems are arranged side by side, and the positions of the four lifting containers of the two sets of gravity turbine systems arranged side by side are distributed in a field shape.

[0007] Furthermore, the lifting container includes a lifting container body, a flow guide cover is provided above the lifting container body, and a wire rope connecting device for connecting a wire rope is provided above the flow guide cover.

[0008] Furthermore, both the upper warehouse conveying and loading and unloading system and the lower warehouse conveying and loading and unloading system include a transport vehicle; each transport vehicle includes a transport vehicle body, a vehicle-mounted conveying mechanism is arranged above the transport vehicle body, and an anti-slip mechanism is also arranged above the transport vehicle body, and the upper surface of the anti-slip mechanism has an anti-slip portion; a lifting mechanism is connected between the transport vehicle body and the vehicle-mounted conveying mechanism, and / or between the transport vehicle body and the anti-slip mechanism.

[0009] Furthermore, the upper warehouse conveying and loading and unloading system and the lower warehouse conveying and loading and unloading system both include a transport vehicle and a vehicle track; each transport vehicle includes a transport vehicle body, the bottom of the transport vehicle body has main wheels, and the bottom of the transport vehicle body is also provided with anti-rollover auxiliary wheels; the main wheels and the anti-rollover auxiliary wheels are slidably connected to the vehicle track and are matched and engaged.

[0010] Furthermore, both the upper warehouse conveying and loading and unloading system and the lower warehouse conveying and loading and unloading system include a transport vehicle, and a heavy object block locking mechanism is arranged above the transport vehicle; a locking groove is arranged at the lower part of the heavy object block, and the locking groove matches the shape of the heavy object block locking mechanism.

[0011] Furthermore, an overwinding and overreleasing buffer device is provided at a position of the vertical shaft close to the upper bin and the lower bin, and / or a hydraulic locking device is provided at a position of the vertical shaft close to the upper bin and the lower bin.

[0012] According to the technical solution of the present invention, the present invention further provides an operation method of a vertical shaft type gravity energy storage system, using the vertical shaft type gravity energy storage system of the present invention; and,

[0013] The energy storage process includes the following steps: in a set of gravity turbine system, the lifting container at the bottom platform is loaded with heavy objects from the lower warehouse, and the lifting container at the wellhead platform is empty. The electric generator is started to drive the gravity turbine system to work, so that the lifting container loaded with heavy objects rises to the wellhead platform, and the empty lifting container descends to the bottom platform at the same time, and then the two lifting containers carry out their respective loading and unloading work at the same time; then the above process is repeated, so that the heavy objects stored in the lower warehouse are lifted one by one to the upper warehouse for storage;

[0014] The energy release process includes the following steps: in a set of gravity turbine system, the lifting container at the wellhead platform is loaded with heavy objects from the upper warehouse, and the lifting container at the well bottom platform is empty. The lifting container loaded with heavy objects descends to the well bottom platform under the action of gravity. This process drives the electric generator to rotate and generate electricity, and at the same time, the empty lifting container rises to the wellhead platform. Then, the two lifting containers carry out their respective loading and unloading work at the same time. Then, the above process is repeated, and the heavy objects stored in the upper warehouse are descended to the lower warehouse one by one for storage.

[0015] Furthermore, the operation of two or more gravity turbine systems is cross-operated so that the power fluctuation of the total power formed by superimposing the power of all gravity turbine systems meets the grid connection requirements.

[0016] According to the technical solution of the present invention, the present invention also provides a design method of a vertical shaft type gravity energy storage system, which is used for the vertical shaft type gravity energy storage system of the present invention; the design method comprises the following steps:

[0017] Firstly, the power model, efficiency model, economic model and basic model of shaft gravity energy storage system are established respectively, and then the multi-objective optimization algorithm is optimized by using the above models to determine the best configuration and parameter combination.

[0018] Among them, the power model includes the system static calculation formula:

[0019] ,

[0020] Among them, F j is the system static force, k is the system resistance coefficient, Q is the mass of the weight block, N2 is the number of tail ropes of equal weight, q k is the mass per unit length of the tail rope of equal weight, N1 is the number of wire ropes, p k is the mass per unit length of the wire rope, H is the depth of the shaft, g is the acceleration due to gravity, ΣM is the displacement mass of the system, and a is the acceleration of the weight block;

[0021] Then, the output power is:

[0022] ,

[0023] Where P(t) is the output power at time t, v(t) is the speed of the weight at time t;

[0024] The efficiency model includes:

[0025] The gravity energy storage system converts excess electrical energy into the gravitational potential energy of heavy objects, and then converts the gravitational potential energy into electrical energy when needed. Therefore, the system efficiency can be expressed as the product of energy storage efficiency and power generation efficiency, that is:

[0026] ,

[0027] Among them, η cn is the energy storage efficiency, η sn For power generation efficiency;

[0028] ,

[0029] Among them, E q is the energy consumed by the weight to rise, η 电机 is the efficiency of the electric generator, η 变流器 is the bidirectional converter efficiency;

[0030] ,

[0031] Among them, E p The energy released by the falling weight;

[0032] The multi-objective optimization algorithm includes the following objective functions, evaluation indicators and constraints:

[0033] The objective function is a multi-objective optimization model based on system performance and grid adaptability function:

[0034] ,

[0035] in, η is the efficiency of the gravity energy storage system, F is the system construction and operation and maintenance cost, and C is the adaptability to the power grid;

[0036] The evaluation indicators include the grid matching rate and power supply reliability of the gravity energy storage system.

[0037] The expression of the grid matching rate of the gravity energy storage system is:

[0038] ,

[0039] Among them, D EV is the grid matching rate of the gravity energy storage system, is the average power connected to the grid, P w(t) is the power generated by the gravity energy storage system at time t, P L (t) is the power of the power grid at time t; according to D EV Definition of D EV The smaller it is, the more the system's power generation matches the grid, which has a positive effect on the objective function;

[0040] The expression of power supply reliability is:

[0041] ,

[0042] Among them, f EV For power supply reliability, P g (t) is the gravity energy storage power at time t;

[0043] The constraints include:

[0044] Power dispatch power constraints, namely:

[0045] ;

[0046] Among them, P L,min is the lower limit of grid power demand, P L,max The upper limit of power demand of the power grid;

[0047] Gravity energy storage constraints, namely:

[0048] ,

[0049] Among them, W sn is the energy stored in the gravity energy storage system, η sn is the discharge efficiency, m is the mass of the weight, g is the acceleration of gravity, Δh is the height change, Δt is the time change, ΔW sn is the energy released by the gravity energy storage system, S t , S max , S min are the storage capacity of the gravity energy storage system at time t and its maximum and minimum values, respectively, h max is the maximum height of the gravity energy storage system shaft, T t The total time the system generates electricity.

[0050] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0051] 1. Long-term energy storage is an important direction for the future development of energy storage. Continuous discharge and large capacity are important indicators of long-term energy storage. The present invention is mainly aimed at large-capacity long-term energy storage, which can achieve goals such as ultra-large lifting height, ultra-heavy energy density, and ultra-large single-unit capacity, and achieve high conversion efficiency, low economic cost, long service life, and high safety factor.

[0052] 2. The present invention adopts a multi-objective optimization algorithm in the system design process. Aiming at the key indicators and parameters of the gravity energy storage system, a multi-objective optimization model of the gravity energy storage system is established, including a basic model, an efficiency model, a power model, and an economic model. The above model is then used to perform multi-objective optimization processing, with the goals of improving energy conversion efficiency, reducing costs, and enhancing grid adaptability. The motor model and parameter optimization are carried out, covering motor characteristics, efficiency, and electromagnetic characteristics, and the motor performance is improved by adjusting the number of magnetic poles, coil winding design, etc. At the same time, the converter efficiency is optimized, and the appropriate converter type, control algorithm, and circuit topology are selected to ensure the high efficiency of power conversion. On this basis, a grid adaptability simulation is carried out, and the stability and adaptability of the system under different grid conditions are considered in combination with the results of multi-motor electromagnetic simulation. Select an appropriate optimization algorithm, such as a genetic algorithm or a particle swarm algorithm, to find the best configuration and parameter combination for the multi-objective optimization model.

[0053] 3. The present invention uses a simulation platform to collaboratively carry out the simulation model logic construction, digital twin marketing program display, process optimization design, strategy verification, simulation debugging and other work for the rising, conveying, and descending scenes of gravity blocks, which can reduce the design, development, debugging, and transportation costs and time, improve equipment efficiency and reliability, and reduce safety risks. In the project development stage, in the absence of relevant reference schemes and materials for engineering scenes, the construction of three-dimensional models can complete the construction of engineering scenes and program planning, and output simulation data; in the process of project implementation, through the function of virtual debugging of gravity energy storage innovation engineering, simulate the different control logics of gravity energy storage innovation engineering, connect with third-party MATLAB and PLC software to find the best experimental data, improve the speed of project demonstration, shorten the R&D cycle, and reduce the risk of the program. It can also train relevant practitioners of gravity energy storage innovation engineering through VR virtual reality technology; in the design stage of the engineering project, when specific mechanical, electrical and IT designs are required, the project can be closer to the actual on-site data, and the early program planning simulation data can be corrected, thereby reducing the project debugging cycle and training cycle in the engineering design, implementation, and acceptance stages, optimizing the layout and improving the process, and creating and testing a robust gravity energy storage solution.

[0054] 4. In view of the characteristics of gravity energy storage system in lifting heavy objects, high lifting height and fast lifting speed, the lifting system in the present invention adopts a multi-rope friction form, which can greatly increase the weight of the energy storage medium, improve the unit capacity density and energy storage efficiency.

[0055] 5. The present invention adopts a multi-rope friction gravity turbine, and two lifting containers are fixed at both ends of the wire rope that bypasses the driving drum (gravity turbine friction wheel), so that the two lifting containers can be transported alternately. When one lifting container is transported to the upper wellhead, the other lifting container just reaches the bottom of the well below, which can realize continuous transportation of heavy logistics, thereby reducing the system's idle time and improving the system's power generation efficiency.

[0056] 6. The present invention adopts a new type of lifting container, which is different from the cage, skip, bucket, etc. of the traditional hoist. A guide device is arranged on the top of the lifting container, which can effectively reduce the airflow resistance during high-speed lifting, reduce system loss, and improve system efficiency; the tank body adopts a hybrid structure, which is connected by two vertical side bodies and a cross beam, each side body is composed of four groups of columns covered with steel plates, and the inner wall of the side body is provided with a heavy block stabilizing device (such as a clamping device) so that the lifting container can be suitable for large-size and heavy-weight heavy blocks.

[0057] 7. In view of the characteristics of gravity energy storage system in transporting heavy objects, high center of gravity of heavy objects and fast transportation speed, the heavy object conveying system of the present invention adopts multi-channel horizontal longitudinal transfer storage and multi-channel horizontal transverse transfer design scheme, realizing one horizontal and one vertical two-way composite operation, and maximizing the operation efficiency; the overall storage system uses a dense storage method to store heavy blocks, which occupies a small area and has a small total equipment investment. It uses a separately developed storage scheduling system to achieve efficient and rapid operation; the transportation equipment uses a special RGV super-heavy-load fast-running transfer vehicle, which can realize the rapid loading, unloading, transfer and storage of heavy blocks, and at the same time has advanced technologies such as anti-collision, dumping prevention, anti-sliding of heavy blocks, and intelligent positioning.

[0058] 8. The present invention arranges two sets (or multiple sets) of gravity turbine lifting systems in a vertical shaft at the same time. The lifting, transportation and loading and unloading processes of heavy blocks are carried out alternately. Multiple machines work together to smoothly output power. Uninterrupted and continuous power generation can be achieved during the energy release process, overcoming the disadvantage of the prior art that power generation cannot be continuous.

[0059] 9. The present invention can realize modular construction and simultaneous construction of multiple modules, which can achieve ultra-large capacity and long-term energy storage.

[0060] 10. The main structure of the weight block in the present invention is composed of a high-strength metal shell and internal fillers. The internal fillers are made of concrete blocks, metal blocks, gravel generated by shaft excavation, and construction waste, and are filled in layers according to density. This not only reduces material costs and gravel processing costs and achieves comprehensive resource utilization, but also lowers the center of gravity of the weight block through layered design, reducing the risk of tipping.

[0061] 11. The shaft-type gravity energy storage system of the present invention has a network control technology in the new power system, which can effectively improve the system short-circuit current level and improve the system strength; provide damping and inertia for the system, improve the system frequency stability; respond quickly when the system loses step and is disconnected, improve the stability of the first swing cycle of the system, and actively support the system recovery; weaken the impact of inter-harmonics and unbalanced voltage in the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1is a schematic diagram of a system structure according to an embodiment of the present invention.

[0063] Figure 2 yes Figure 1 Schematic side view of the structure shown.

[0064] Figure 3 yes Figure 1 A schematic diagram of the structure from above at the shaft in the illustrated embodiment.

[0065] Figure 4 yes Figure 1 A schematic diagram of the structure of a gravity turbine system.

[0066] Figure 5 It is a schematic structural diagram of a lifting container according to an embodiment of the present invention.

[0067] Figure 6 yes Figure 5 Schematic side view of the structure shown.

[0068] Figure 7 It is a structural schematic diagram of a lower warehouse conveying and loading and unloading system according to one embodiment of the present invention.

[0069] Figure 8 It is a schematic structural diagram of some components of a transport vehicle according to an embodiment of the present invention.

[0070] Fig. 9 It is a schematic structural diagram of the wheels of a transport vehicle according to an embodiment of the present invention.

[0071] Fig.10 It is a perspective structural schematic diagram of a transport vehicle carrying a heavy object according to an embodiment of the present invention.

[0072] Fig.11 It is a schematic diagram of the principle of an operating method according to an embodiment of the present invention.

[0073] Description of reference numerals in the accompanying drawings:

[0074] 1. Shaft; 11. Derrick; 12. Tankway; 13. Separation bracket; 14. Overwinding and overdischarging buffer device; 15. Buffer section; 2. Upper warehouse; 3. Lower warehouse; 31. Buffer conveyor; 32. Main lane; 33. Lane mother car; 34. Sub-lane; 35. Lane sub-car; 36. Storage rack; 37. Transfer mother car; 38. Transfer lane; 4. Lifting container; 41. Lifting container body; 42. Flow guide cover; 43. Wire rope connection device; 44. Tank ear; 45. Weight block stabilization device; 46. Loading Unloading conveyor; 51. First gravity turbine sheave; 52. Second gravity turbine sheave; 53. Gravity turbine friction wheel; 54. Wire rope; 55. Equal weight tail rope; 6. Transport vehicle; 61. Transport vehicle body; 62. On-board transport mechanism; 621. Transport mechanism shell; 63. Anti-slip mechanism; 64. Anti-slip part; 65. Lifting mechanism; 66. Vehicle track; 67. Main wheel; 68. Anti-overturning auxiliary wheel; 681. Auxiliary wheel frame; 69. Weight block locking mechanism; 7. Weight block; 71. Locking groove. DETAILED DESCRIPTION

[0075] The present invention provides a shaft-type gravity energy storage system and its operation and design methods, which solve the problems of low efficiency of existing solutions, and are particularly aimed at large-capacity and long-term energy storage. The system uses a shaft to lift heavy blocks as a technical method for energy storage, thereby achieving goals such as ultra-large lifting height, ultra-heavy energy density, and ultra-large single-unit capacity, and achieving high conversion efficiency, continuous discharge, low economic cost, long service life, and high safety factor.

[0076] In general, the shaft-type gravity energy storage system of the present invention mainly includes a shaft, an upper warehouse, a lower warehouse, a weight block, a weight lifting system, a weight conveying and loading and unloading system, an electric control system, etc. Among them, the weight lifting system is mainly composed of a gravity turbine, a steel wire rope, a lifting container, a tankway, etc., and the weight conveying and loading and unloading system is mainly composed of a loading and unloading conveyor, a buffer conveyor, a tunnel mother car, a tunnel sub-car, a transfer mother car, etc. Driven by the gravity turbine, the steel wire rope drives the lifting container with the weight block to reciprocate up and down along the shaft tankway to realize the storage and release of electrical energy.

[0077] Specifically, see Figures 1 to 4A vertical shaft gravity energy storage system according to one embodiment of the present invention includes a vertical shaft 1, an upper warehouse 2 is provided at the upper part of the vertical shaft 1 (for example, on the ground outside the wellhead), and a lower warehouse 3 is provided at the lower part of the vertical shaft 1. Usually, the vertical shaft 1 may optionally have a buffer section 15 below the lower warehouse 3 to play a buffering role in unexpected situations such as wire rope breakage. A tank channel 12 and a lifting container 4 are provided in the vertical shaft 1, and the lifting container 4 can move up and down along the tank channel 12 between the wellhead platform of the upper warehouse 2 and the well bottom platform of the lower warehouse 3. For the convenience of description, the place where the ground of the upper warehouse 2 and the shaft of the vertical shaft 1 meet is called the wellhead platform, and the place where the ground of the lower warehouse 3 and the shaft of the vertical shaft 1 meet is called the well bottom platform. Under normal operation, the highest position of the lifting container 4 is at the wellhead platform, where the bottom of the lifting container 4 is substantially level with the height of the ground of the upper warehouse 2, so that the heavy blocks 7 can be stably transported into / out of the lifting container 4 to complete the loading and unloading work; similarly, the lowest position of the lifting container 4 is at the well bottom platform, where the bottom of the lifting container 4 is substantially level with the height of the ground of the lower warehouse 3. The upper warehouse 2 has an upper warehouse conveying and loading and unloading system, and the lower warehouse 3 has a lower warehouse conveying and loading and unloading system, which are responsible for the automatic conveying and transfer of the heavy blocks 7 between the storage area of ​​the upper / lower warehouse and the lifting container at the wellhead / well bottom platform. A derrick 11 is arranged directly above the shaft 1.

[0078] It also includes a gravity turbine system, for example, it is arranged on the ground above the wellhead of the shaft 1. In each set of gravity turbine system: it includes a first gravity turbine sheave 51, a second gravity turbine sheave 52 and a gravity turbine friction wheel 53; the first gravity turbine sheave 51 and the second gravity turbine sheave 52 are both arranged on the derrick 11, the second gravity turbine sheave 52 is located obliquely above the first gravity turbine sheave 51, and the gravity turbine friction wheel 53 is located above the ground next to the derrick 11; the gravity turbine friction wheel 53 is connected to the electric generator, and the electric generator is connected to the power grid through a bidirectional converter; a braking device such as a brake device is provided at the gravity turbine friction wheel 53. The first gravity turbine sheave 51, the second gravity turbine sheave 52 and the gravity turbine friction wheel 53 are connected to a steel wire rope 54, and the two ends of the steel wire rope 54 are connected to two lifting containers 4 respectively. The relationship between the positions of the first gravity turbine sheave 51 and the second gravity turbine sheave 52 and the shaft 1 satisfies that when the steel wire rope 54 is naturally vertically drooping, the lifting container 4 is located in the shaft 1 at a set position that matches the tankway 12; the lower ends of the two lifting containers 4 are connected to an equal-weight tail rope 55, and the equal-weight tail rope 55 is, for example, drooped in the buffer section 15 of the shaft 1 below the lower warehouse 3. Figure 4 As shown, when one of the two lifting containers 4 in a gravity turbine system is located at the wellhead platform of the upper warehouse 2 , the other of the two lifting containers 4 is located at the well bottom platform of the lower warehouse 3 .

[0079] It should be noted that a complete gravity energy storage system (gravity energy storage station) has at least two gravity turbine systems, because a gravity turbine system only has stable power output during the stage when the weight block is descending at a uniform speed. In order to be able to operate in parallel with the grid, multiple gravity turbine systems are required to cooperate to achieve a total output power that meets the requirements of the grid. For example, a gravity energy storage station has multiple shafts 1, each shaft 1 is used for a weight lifting system of one or more gravity turbine systems; or there is only one shaft 1, which is shared by multiple gravity turbine systems, etc.; it can be understood that within a certain range, the more gravity turbine systems there are, the more stable the total power can be achieved, and this requires comprehensive consideration in terms of construction cost, energy storage scale, etc. to ensure the lowest comprehensive construction cost and the highest economic benefit. For example, a gravity energy storage station has two shafts 1, and two gravity turbine systems are provided at each shaft 1.

[0080] The gravity turbine system of this solution adopts a wire rope multi-rope friction hoist solution, in which the wire rope 54 and the tail rope 55 of equal weight are multiple ropes arranged side by side, such as 2, 4, 6 or 8 ropes. The wire rope 54 is placed on the friction wheel and the sky wheel, and the friction between the friction pad on the friction wheel and the wire rope 54 is used to transmit the power of the wire rope 54 to lift, so that the two lifting containers 4 at both ends of the wire rope 54 can move up and down at the same time, thereby realizing the upper and lower warehouses in a set of gravity turbine system. In the existing technical solution, a set of gravity turbines only uses one rope to connect one lifting container, and the lifting and transporting of the empty lifting container requires additional gravity turbines. Therefore, this solution is more efficient, requires fewer gravity turbines, and is more economical. This is one of the main innovations of the present invention.

[0081] It should be noted that the lifting structure of the gravity turbine system of this scheme is similar to the multi-rope friction hoist used in the mining industry, but there are many substantial differences between the two. For example, the loading and unloading method of the mining hoist has no requirements for the loading and unloading time, while the gravity energy storage system requires fast loading and unloading efficiency, so a more efficient braking system is needed; the materials that are often lifted and transported in the mining industry are relatively light bulk materials or personnel, and the frequency of transporting large heavy objects is relatively low, while the gravity energy storage system transports ultra-large mass heavy blocks, and they must be transported continuously and at a high frequency. Therefore, in addition to the lifting load, lifting speed, and transfer speed of the gravity turbine in the gravity energy storage system far exceeding that of ordinary mining hoists, it is necessary to be specially equipped with an electric generator to realize the two functions of energy storage and energy release; in addition, a set of special lifting containers is required to accommodate ultra-large mass heavy blocks, and at the same time, it is also necessary to realize the rapid and automatic loading and unloading of heavy blocks, as well as to ensure the stability and anti-overturning of heavy blocks during transportation.

[0082] Preferably, if Figure 3In the illustrated embodiment, in a shaft 1, the lifting containers 4 of two sets of gravity turbine systems are arranged side by side (which can be referred to as the "one shaft, two machines" scheme), and the positions of the four lifting containers 4 of the two sets of gravity turbine systems are distributed in a field shape. A partition bracket 13 (or tank beam) is arranged in the shaft 1. The partition bracket 13 is, for example, arranged at a layer every few meters along the depth direction of the shaft 1 and fixed on the side wall of the shaft 1. The partition bracket 13 divides the cross section of the shaft 1 into a field-shaped structure, and the lifting containers 4 are located in four vertical channels surrounded by the shaft 1 and the partition bracket 13. Both sides of each lifting container 4 are slidably connected to the tank 12, and the tank 12 is arranged on the side of the shaft 1 and the partition bracket 13. It can be understood that for the "one shaft, one machine" or "one shaft, multiple machines" scheme, the partition bracket 13 can be designed to divide the shaft of the shaft 1 into two times the number of gravity turbine systems in a similar manner, so as to provide the lifting and lowering of the lifting containers 4 of the number.

[0083] For further information, see Figure 5 , Figure 6 The lifting container 4 of the preferred embodiment includes a lifting container body 41 in the shape of a box, and one side of the lifting container body 41 has an entrance and exit for the heavy object block 7 to enter and exit. A deflector 42 is provided above the lifting container body 41. The deflector 42 is preferably, for example, a triangle or bullet-shaped cross-section with a small top and a large bottom. The deflector 42 is fixedly connected to the top of the lifting container body 41 inside (below) through a bracket structure. The lifting container body 41 is provided with tank ears 44, such as pulleys, on the left and right sides of the upper and lower ends, so as to cooperate with the tank channel 12, and the part of the tank ears 44 that cooperates with the tank channel 12 is exposed outside the deflector 42. A wire rope connecting device 43 for connecting a wire rope 54 is provided above the deflector 42. The wire rope connecting device 43 can be fixedly connected to the deflector 42 or fixedly connected to the lifting container body 41. The wire rope connecting device 43 is, for example, a row of multiple joints, and the projection of the deflector 42 in another horizontal direction is rectangular (such as Figure 6 As shown in the figure, the deflector 42 is in the shape of a curved plate as a whole, so that a wire rope connecting device 43 can be stably arranged above it. Preferably, the shape of the internal space of the lifting container body 41 matches the weight block 7 and is slightly larger than the weight block 7. The inner wall of the lifting container body 41 is provided with a weight block stabilizing device 45, such as a clamping device, which clamps the weight block 7 from both sides to prevent it from shaking during the lifting process. The bottom of the lifting container body 41 is also provided with a loading and unloading conveyor 46, such as a roller conveying mechanism, to assist in the input and output of the weight block 7.

[0084] See also Figure 7 and Figure 4, respectively, the structure of the lower warehouse 3 and the lower warehouse conveying and loading and unloading system is shown from two angles, and the upper warehouse 2 and the upper warehouse conveying and loading and unloading system can be selected to be similar to or the same as the lower warehouse conveying and loading and unloading system. The space of the upper warehouse 2 and the lower warehouse 3 is provided with a main lane 32 and a sub-lane 34. The main lane 32 is connected to the shaft of the shaft 1, and the sub-lane 34 is arranged in parallel. The multiple sub-lanes 34 are connected to the main lane 32 at different positions. The optional arrangement of the main lane 32 and the sub-lane 34 includes but is not limited to the sub-lane 34 being distributed in parallel or radially. The main lane 32 is only used for the transportation (and loading and unloading) of heavy blocks, while the sub-lane 34 (at least part of the area) is also used as a storage area for heavy blocks.

[0085] The upper warehouse conveying and loading and unloading system and the lower warehouse conveying and loading and unloading system both include a buffer conveyor 31, a lane mother car 33, and a lane sub-carriage 35. The buffer conveyor 31 is, for example, a roller conveying mechanism. The buffer conveyor 31 is located in the main lane 32 and is adjacent to the shaft of the shaft 1. Its position can be called a buffer area. Taking the lower warehouse 3 as an example, when the lifting container 4 is located on the bottom platform, the buffer conveyor 31 is adjacent to the loading and unloading conveyor 46 of the lifting container 4, so that the heavy object block 7 can be continuously and stably transported on the buffer conveyor 31 and the loading and unloading conveyor 46. In addition, the heavy object block 7 can also be temporarily placed on the buffer conveyor 31 to achieve a buffering effect. The lane mother car 33 is located in the main lane 32 and between the buffer conveyor 31 and the sub-lane 34. The lane sub-carriage 35 is located in the sub-lane 34. The sub-lane 34 has a storage rack 36 to form a storage area. A number of heavy object blocks 7 are stacked on the storage rack 36 along the length direction of the sub-lane 34. The lane sub-carriage 35 can move along the length direction of the sub-lane 34 and pick up and place the heavy object block 7 on the storage rack 36; the lane mother car 33 can move along the length direction of the main lane 32 to reach the lane entrance of any sub-lane 34, thereby realizing the transfer of the heavy object block 7 between the lane mother car 33 and the lane sub-carriage 35. In this way, the transportation and loading and unloading process of the heavy object block 7 between the upper / lower warehouse storage area and the lifting container 4 can be realized.

[0086] Optionally, each sub-lane 34 has a lane sub-carriage 35. Preferably, one end of the sub-lane 34 away from the main lane 32 is also connected to a transfer lane 38, and multiple sub-lanes 34 are connected to the transfer lane 38 at different positions. A transfer mother car 37 is provided in the transfer lane 38, and the transfer mother car 37 can move along the length direction of the transfer lane 38 to reach the lane entrance of any sub-lane 34, and then the lane sub-carriage 35 can be moved onto the transfer mother car 37, and the transfer mother car 37 can transfer the lane sub-carriage 35 on it to other sub-lanes 34. Such a setting can achieve a smaller number of transport vehicles, and there is no need to equip each sub-lane 34 with a lane sub-carriage 35. For example, after the heavy object block 7 in a sub-lane 34 is emptied, the lane sub-carriage 35 in the sub-lane 34 can be moved to other sub-lanes 34 for transportation through the transfer mother car 37, which has a higher equipment utilization rate and is more economical.

[0087] More specifically, the above transport vehicles all move along corresponding tracks fixed on the ground. In particular, the upper surface of the transfer vehicle 37 has a guide track. When the transfer vehicle 37 moves to the tunnel entrance of the sub-tunnel 34, the guide track is connected with the track on the ground of the sub-tunnel 34, so that the tunnel sub-vehicle 35 can run along the track to the transfer vehicle 37, and then run from the transfer vehicle 37 to the track of other sub-tunnels 34.

[0088] See also Figure 8Preferably, in the above transport vehicles, the lane mother vehicle 33 and the lane sub-vehicle 35 adopt customized RGV super-heavy-load fast-running transfer vehicles. It should be noted that in other optional conveying and loading and unloading systems, there is usually also a transport vehicle 6 for mobile transportation of heavy blocks 7, which can also adopt the structure of the RGV super-heavy-load fast-running transfer vehicle of this scheme to obtain the corresponding technical effect. In this scheme, each RGV super-heavy-load fast-running transfer vehicle includes a transport vehicle body 61, and a vehicle-mounted conveying mechanism 62 is arranged above the transport vehicle body 61, such as a roller conveying mechanism, and an anti-slip mechanism 63 is also arranged above the transport vehicle body 61, for example, it is located between the rollers of the roller conveying mechanism, and the upper surface of the anti-slip mechanism 63 has an anti-slip portion 64, such as an anti-slip pad. A lifting mechanism 65 is connected between the transport vehicle body 61 and the vehicle-mounted conveying mechanism 62, and / or between the transport vehicle body 61 and the anti-slip mechanism 63, so as to realize the lifting and lowering of the structure for supporting the heavy object block and the relative lifting and lowering (function switching) between the vehicle-mounted conveying mechanism 62 and the anti-slip mechanism 63. For example, the anti-slip mechanism 63 is a beam structure fixed above the transport vehicle body 61, and the lifting mechanism 65 is connected below the vehicle-mounted conveying mechanism 62. The heavy object block 7 is placed on the storage rack 36 on both sides in the upper warehouse / lower warehouse, and the transport vehicle 6 is located between the storage racks 36 on both sides and below the heavy object block 7, so that the process of taking and placing the heavy object block 7 can be realized by lifting and lowering the vehicle-mounted conveying mechanism 62; after leaving the storage rack, the vehicle-mounted conveying mechanism 62 is lowered, and the anti-slip part 64 contacts the heavy object block 7 to play an anti-slip role, which helps to realize stable and fast transportation; or, the anti-slip mechanism 63 or the anti-slip part 64 is connected to an independent lifting mechanism, which can be raised to actively contact the heavy object block 7 to achieve anti-slip.

[0089] See also Fig. 9 Preferably, the upper warehouse conveying and loading and unloading system and the lower warehouse conveying and loading and unloading system also include a vehicle track 66 for the transport vehicle 6 (specifically, the lane mother vehicle 33, the lane child vehicle 35, and the transfer mother vehicle 37), for example, a rail welded and fixed on the ground, and the vehicle track 66 is, for example, two left and right rails, which respectively cooperate with the wheels on both sides of the bottom of the transport vehicle body 61. The bottom of the transport vehicle body 61 has a main wheel 67, and the bottom of the transport vehicle body 61 is also provided with an anti-overturning auxiliary wheel 68. One side of the main wheel 67 has a baffle, and the anti-overturning auxiliary wheel 68 is arranged on the other side through the auxiliary wheel frame 621, so that the transport vehicle 6 and the vehicle track 66 are positioned on both sides respectively. In other words, the main wheel 67 and the anti-overturning auxiliary wheel 68 are slidably connected and matched with the vehicle track 66, so that the transport vehicle 6 can be effectively prevented from overturning as a whole when transporting heavy objects.

[0090] See also Fig.10Preferably, a weight block locking mechanism 69, such as a T-shaped rod / block, is provided above the transport vehicle body 61 of the transport vehicle 6 (specifically, the lane mother vehicle 33 and the lane child vehicle 35); a locking groove 71 is provided at the lower part of the weight block 7, and the locking groove 71 matches the shape of the weight block locking mechanism 69 and passes through in the transport direction of the weight block 7; so that when the transport vehicle 6 is taking and placing the weight block 7 (and transferring the weight block 7 between the lane mother vehicle 33 and the lane child vehicle 35), the weight block locking mechanism 69 can slide into / out of the locking groove 71. When transporting the weight block 7, the weight block locking mechanism 69 is located in the locking groove 71, thereby effectively preventing the weight block 7 from tipping over. Furthermore, above the transport vehicle body 61 is a conveying mechanism housing 621, and the vehicle-mounted conveying mechanism 62 and the anti-slip mechanism 63 are both located in the conveying mechanism housing 621. The top of the conveying mechanism housing 621 is a plane and is provided with a through hole to expose the vehicle-mounted conveying mechanism 62 (and the anti-slip portion 64) above. The weight block locking mechanism 69 is, for example, fixedly connected to the conveying mechanism housing 621 and can be lifted and lowered with the lifting mechanism 65; or the weight block locking mechanism 69 is fixedly connected to the transport vehicle body 61 and cannot be lifted and lowered (if so, the shape of the locking groove 71 needs to be adjusted accordingly so that the weight block locking mechanism 69 is located in the locking groove 71 in the lifting state of picking and placing).

[0091] Furthermore, an overwinding and overdischarging buffer device 14 is provided at the position of the vertical shaft 1 near the upper warehouse 2 and the lower warehouse 3, and more specifically, it is provided above the highest position and below the lowest position of the lifting container 4 in the vertical shaft 1 under normal circumstances. Under normal circumstances, the lifting container 4 is stopped at the wellhead / well bottom platform of the upper / lower warehouse by the braking device. If it fails to stop due to a malfunction or the like, that is, an overwinding and overdischarging situation occurs, the overwinding and overdischarging buffer device 14 can play a buffering role to ensure that the lifting container 4 does not deviate from the normal lifting range. A hydraulic locking device is provided at the position of the vertical shaft 1 near the upper warehouse 2 and the lower warehouse 3. The hydraulic locking device is used to lock the lifting container 4 after the lifting container 4 is lifted / lowered into place, so as to prevent the lifting container 4 from rising and falling due to the elastic expansion and contraction of the wire rope when the heavy object 7 enters and exits the lifting container 4, thereby ensuring the stable transportation of the heavy object 7.

[0092] Based on the shaft-type gravity energy storage system of the present invention, the present invention provides an operation method of the shaft-type gravity energy storage system, which can further reflect the technical effect of the present solution, and mainly includes the following contents:

[0093] The energy storage process includes the following steps: in a set of gravity turbine system, the lifting container 4 at the bottom platform below the shaft 1 is loaded with heavy blocks 7 from the lower warehouse 3, and the lifting container 4 at the wellhead platform above the shaft 1 is unloaded. The electric generator is started to drive the gravity turbine system to work, so that the lifting container 4 loaded with heavy blocks rises to the wellhead platform above the shaft 1, and the unloaded lifting container 4 descends to the bottom platform below the shaft 1, and then the two lifting containers 4 carry out their respective loading and unloading work at the same time; then the above process is repeated, so that the heavy blocks stored in the lower warehouse 3 are lifted one by one to the upper warehouse 2 for storage.

[0094] More specifically, during energy storage, the heavy blocks stored in the lower warehouse are transported to the buffer area by the tunnel sub-trolley and the tunnel mother car, and are transferred to the buffer conveyor through the on-board conveying mechanism on the tunnel mother car. The buffer conveyor transfers the heavy blocks to the lifting container next to the bottom platform of the shaft, and then the heavy blocks continue to be transferred to the inside of the lifting container through the loading and unloading conveyor in the lifting container and placed stably. The electric generator is started to drive the gravity turbine friction wheel of the gravity turbine to rotate rapidly. Under the action of friction, the wire rope drives the lifting container carrying the heavy blocks to accelerate to the set speed, and then runs at a constant speed. When the lifting container is about to run to the wellhead platform position above the shaft, the braking device is started, and the gravity turbine decelerates until the lifting container stops at the wellhead platform position above the shaft, and the liquid The dynamic locking device locks the lifting container, and the loading and unloading conveyor of the lifting container transfers the heavy block to the buffer conveyor of the upper warehouse. The buffer conveyor transfers the heavy block to the tunnel mother car, and the tunnel mother car transfers the heavy block to the tunnel sub-car, and the tunnel sub-car then transports the heavy block to the designated position of the upper warehouse for storage; at the same time, the empty lifting container at the other end of the wire rope also undergoes the same acceleration, uniform speed, and deceleration descending process, and finally stops at the bottom platform position under the shaft at the same time, and completes the conveying, transfer and loading process of another heavy block in the lower warehouse; then the electric generator rotates in the opposite direction, drives the gravity turbine to rotate the drum, drives the wire rope to lift the heavy block, and enters the next energy storage process, and repeats this operation until the specified energy storage capacity is completed.

[0095] The energy release process includes the following steps: in a set of gravity turbine system, the lifting container 4 at the wellhead platform above the shaft 1 is loaded with weight blocks 7 from the upper warehouse 2, and the lifting container 4 at the well bottom platform below the shaft 1 is empty. The lifting container 4 loaded with weight blocks descends to the well bottom platform below the shaft 1 under the action of gravity. This process drives the electric generator to rotate and generate electricity, and at the same time, the empty lifting container 4 rises to the wellhead platform above the shaft 1. Then, the two lifting containers 4 carry out their respective loading and unloading work at the same time, and then repeat the above process, and the weight blocks stored in the upper warehouse 2 are descended to the lower warehouse 3 one by one for storage;

[0096] More specifically, when releasing energy, the heavy blocks stored in the upper warehouse are transported to the buffer area by the tunnel sub-trolley and the tunnel mother car, and are transferred to the buffer conveyor through the on-board conveyor on the tunnel mother car. The buffer conveyor and the loading and unloading conveyor transfer the heavy objects to the lifting container at the platform at the shaft mouth for stable placement. The lifting container carrying the heavy blocks descends rapidly under the action of gravity. Under the action of friction, the wire rope drives the friction wheel of the gravity turbine to rotate rapidly, driving the electric generator to rotate at high speed and generate electricity. When the lifting container is about to descend to the platform at the bottom of the shaft, the braking device is started, and the gravity turbine decelerates until the lifting container stops at a specific position at the bottom of the shaft. The hydraulic locking device locks the lifting container, and the lifting container's own The loading and unloading conveyor transfers the heavy blocks to the lower warehouse buffer conveyor that is already in place and waiting. The buffer conveyor transfers the heavy blocks to the tunnel mother car. The tunnel mother car transfers the heavy blocks to the tunnel sub-car, and the tunnel sub-car then transports the heavy blocks to the designated position of the lower warehouse. At the same time, the empty lifting container at the other end of the wire rope also undergoes the same lifting operation process of acceleration, uniform speed, and deceleration, and finally stops at the designated position of the wellhead platform at the same time, completing the transportation, transfer and loading process of another heavy block in the upper warehouse. Then, under the action of the lifting container's own gravity, the wire rope drives the electric generator to rotate in the opposite direction through the friction wheel of the gravity turbine and enters the next energy release process. This operation is repeated until the specified energy release capacity is completed.

[0097] Furthermore, the operation of two or more gravity turbine systems is carried out crosswise, so that the total power obtained by superimposing the power of all gravity turbine systems tends to be stable and the power fluctuation meets the grid connection requirements.

[0098] Furthermore, the operation parameters of the crossover are calculated by the following steps:

[0099] The power of a single gravity energy storage unit when generating electricity (releasing energy) has the following formula relationship:

[0100] ,

[0101] Among them, P Cd is the power generated during power generation, k is the system resistance coefficient, m is the mass of the weight block, g is the gravitational acceleration, ΣM is the system displacement mass, a is the system operation acceleration, and V is the system operation speed.

[0102] The output power is related to the speed and acceleration of the weight. Before and after the acceleration or braking process, the rapid change in acceleration causes a large change in the output power. At the end of acceleration and the beginning of braking, the kinetic power is converted into discharge power, resulting in an increase in output power. In order to meet the power system's fluctuating requirements for energy storage power, the output curve needs to be optimized.

[0103] A gravity energy storage system (gravity energy storage station) contains multiple gravity energy storage units, and a gravity energy storage unit contains a set of gravity turbine systems. The power fluctuation of a single gravity energy storage unit is large, and the overlapping and crossing technology of multiple gravity energy storage units is adopted to coordinate the control of each gravity energy storage unit to achieve mutual compensation, thereby stabilizing the output power of the gravity energy storage system.

[0104] In the process of power generation (energy release), the power P cd It is a periodic function with a period of single transmission time T, that is:

[0105] ;

[0106] For a gravity energy storage unit, once the transmission path and transmission speed are set, the original settings will not be easily changed in steady state. Therefore, in the gravity energy storage system, only the number of parallel gravity energy storage units N and the grid connection time λ of each unit are changed. For the output power P of the gravity energy storage system, there is:

[0107] ;

[0108] Among them, P cdN is the power of the Nth gravity energy storage unit when generating electricity, λ N is the grid-connected time of the Nth gravity energy storage unit (the grid-connected time is also the initial phase of the periodic function);

[0109] It is required to ensure that the power fluctuation in any time period is less than the defined value required by the power grid, that is:

[0110] ,

[0111] Among them, B is the output power fluctuation rate required by the power grid, and t1 and t2 are any two time points.

[0112] Cooperative control routes such as Fig.10 As shown. Among them, S1, S2, ..., SN are the output curves of each gravity energy storage unit. Through different grid connection times, N gravity energy storage units are connected in parallel, and the power is superimposed to achieve the ideal stable power value Sq.

[0113] By using a decomposed traversal algorithm, the problem to be solved is divided into several sub-problems, each sub-problem is solved to obtain the local optimal solution of the sub-problem, and then the local optimal solutions of the sub-problems are combined into a solution to the original problem.

[0114] The N gravity energy storage units are superimposed and split into two gravity energy storage units, that is:

[0115] ,

[0116] The objective function is:

[0117] ,

[0118] in, is the power value of the nth gravity energy storage unit at time t, is the average power value of the nth gravity energy storage unit, and Sq is the ideal stable power value.

[0119] Combined with the above formula, determine the different grid connection time λ of each gravity energy storage unit n Connected to the grid, their output power waveforms are superimposed to achieve smooth output.

[0120] The present invention also provides a design method for a vertical shaft type gravity energy storage system, which is used for the vertical shaft type gravity energy storage system of the present invention; the design method comprises the following steps:

[0121] Considering that the key indicators of the gravity energy storage system mainly include three aspects: power, efficiency and economy, when designing the gravity energy storage system, we first establish the power model, efficiency model, economic model and the basic model of the shaft-type gravity energy storage system, and then use the above models to optimize the multi-objective optimization algorithm to determine the optimal configuration and parameter combination.

[0122] Among them, the basic model is the necessary modeling in the conventional design process. Specifically, when modeling the gravity energy storage system, in most cases, it can be represented as six basic modules, namely: heavy object model (lifting system), mechanical transmission model (mechanical system), motor and machine-side / grid-side converter model, speed control system, machine-side control system, and grid-side control system.

[0123] The power model includes the following:

[0124] The power equation for a falling object is: ,

[0125] The falling process of the heavy object in the model is considered to be three-stage, including: acceleration stage, uniform speed stage, and deceleration stage. The corresponding times are t1, t2, and t3, and the corresponding falling heights are H1, H2, and H3 respectively.

[0126] Kinematics:

[0127] For the acceleration phase:

[0128] ,

[0129] For the uniform velocity phase:

[0130] ,

[0131] For the deceleration phase:

[0132] ,

[0133] The system static calculation formula is:

[0134] ,

[0135] Among them, F j is the system static force, k is the system resistance coefficient, Q is the mass of the weight block, N2 is the number of tail ropes of equal weight, q k is the mass per unit length of the tail rope of equal weight, N1 is the number of wire ropes, p k is the mass per unit length of the wire rope, H is the depth of the shaft, g is the acceleration due to gravity, ΣM is the displacement mass of the system, and a is the acceleration of the weight block (system operation acceleration).

[0136] Output power:

[0137] ,

[0138] Among them, P(t) is the output power at time t, and v(t) is the speed of the weight at time t.

[0139] The efficiency model includes the following:

[0140] The gravity energy storage system converts excess electrical energy into the gravitational potential energy of a heavy object, and then converts the gravitational potential energy into electrical energy when needed. It can be expressed as the product of energy storage efficiency and power generation efficiency:

[0141] ,

[0142] Among them, η cn is the energy storage efficiency, η sn For power generation efficiency.

[0143] In the energy storage stage, the system electric energy is converted and transmitted by the bidirectional converter, the motor (electric generator) and the transmission system to drive the weight block to rise. The weight block overcomes the wind resistance loss caused by wind resistance, the rolling loss caused by rolling friction, and the speed loss caused by the inertia force of its mass during acceleration. Finally, the energy is stored in the form of gravitational potential energy. The energy storage efficiency can be expressed as:

[0144] ,

[0145] Among them, E q The energy consumed by the weight to rise; η 电机 is the efficiency of the electric generator; η 变流器 is the efficiency of the bidirectional converter.

[0146] In the power generation stage, the power source of the system is the gravitational potential energy of the heavy object. During the descending movement, the wind resistance loss caused by wind resistance and the rolling loss caused by rolling friction are overcome to realize the conversion of gravitational potential energy into kinetic energy. A small part of the kinetic energy is converted into speed loss, and the remaining kinetic energy is converted into electrical energy by driving the electric generator through the transmission system. After that, it is connected to the power grid through the bidirectional converter. The power generation efficiency can be expressed as:

[0147] ,

[0148] Among them, E p The energy released by the falling weight.

[0149] The economic model includes the following:

[0150] The levelized cost of electricity is used to model the economic model of gravity energy storage. The levelized cost of electricity (LCOE) is the cost per kilowatt-hour (kWh). The levelized cost of electricity is defined as the unit cost per kilowatt-hour or megawatt-hour of energy in the payment flow, and its present value is the same as the total cost of commissioning and operating the power plant during its life cycle. The levelized cost of electricity is a common indicator for determining the cost of power generation technology.

[0151] The calculation formula specifically includes:

[0152] ,

[0153] Among them, C life E is the life cycle cost, which mainly refers to the total cost of power generation assets in all periods; life The life cycle energy production value refers to the total energy produced by the power generation asset in all time periods.

[0154] The life cycle costs (i.e. expenditures) include the initial investment cost C inv , Maintenance and operation costs C OM , replacement cost C R 、Charging cost C C and subsequent recovery costs C Rec .

[0155] (1) Initial investment cost C inv That is, the cost of building an energy storage system, including the total cost of design, hardware, software, engineering, procurement, construction, etc. According to the characteristics of energy storage technology, the initial investment cost can be divided into capacity cost, C E and power cost C P ,Right now:

[0156] ,

[0157] Among them, the power cost C P Including power electronic equipment, motor / generator sets, transformers and cables, etc.; capacity cost C E Including weights, steel frames (steel frame structures in frame-type gravity energy storage and shafts in mine-type), rotating wheels and steel ropes, etc. Power cost C P It can be understood as the investment cost based on electricity, capacity cost C E It can be understood as energy-based investment cost.

[0158] Capacity cost C E Refers to the cost of equipment and construction related to energy storage capacity in the energy storage system, such as weights, steel frames (steel frame structure in frame-type gravity energy storage, shaft in mine-type), rotating wheels and wire ropes and other corresponding structures and construction costs. The available unit energy storage capacity cost U E (yuan / (MW•h)) and energy storage capacity Q E (MW•h) calculation, that is:

[0159] ;

[0160] Power cost C P Refers to the cost of power-related equipment and construction in the energy storage system, including power electronic equipment, motor / generator sets, transformers and cables, etc. The available unit power cost U P (yuan / MW) and installed capacity W P (MW) calculation, namely:

[0161] ;

[0162] (2) Annual maintenance and operation cost C OM Refers to the cost incurred during the annual operation and maintenance of the energy storage system, which can be mainly divided into capacity maintenance cost C E,OM , Power maintenance cost C P,OM and labor operation cost C labor ,Right now:

[0163] ;

[0164] Capacity maintenance cost refers to the maintenance cost of equipment related to capacity, expressed as unit energy storage capacity maintenance cost U EOM (yuan / (MW•h)) and energy storage capacity Q E (MW•h) calculation, that is:

[0165] ;

[0166] Power maintenance cost refers to the maintenance cost of power-related equipment, expressed as unit power maintenance cost U POM (yuan / MW) and installed capacity WP (MW) calculation, namely:

[0167] ;

[0168] Labor operation cost refers to the expenditure related to operation and maintenance personnel, which can be calculated based on the number of project operation and maintenance personnel n labor and the annual cost per personU labor Calculate, that is:

[0169] ,

[0170] (3) Replacement cost C R Refers to the cost incurred in the process of replacing components due to factors such as the life of energy storage system components, which need to be replaced at specified time intervals. Replacement cost can be replaced per unit energy storage capacity U R (yuan / (MW•h)) and energy storage capacity Q E (MW•h) calculation, that is

[0171] ,

[0172] (4) Charging cost C C Refers to all the costs of charging the energy storage system from the grid or renewable energy source during its entire life cycle, expressed as the charging unit price U C (Yuan / (MW•h)), power per charge Q C (MW•h) and annual charging times N y Calculate, that is:

[0173] ,

[0174] in,

[0175] ,

[0176] θ DOD is the depth of discharge and η is the charge and discharge efficiency.

[0177] (5) Recovery cost C Rec It refers to the difference between the cost of dismantling the energy storage system at the end of its service life and the income from the secondary use of the equipment. If the dismantling cost is greater than the income from the secondary use, the recovery cost is positive; if the dismantling cost is less than the income from the secondary use, the recovery cost is negative. EOL ) is the ratio of the recovery cost to the initial investment, which can be positive or negative, then:

[0178] .

[0179] (6) Total cost calculation formula Among the above costs, the initial investment cost is the one-time investment cost when the project is constructed, and the rest are annual costs. Considering the time when the energy storage power station is put into operation as the starting point for calculation, the net present value of the total cost over the entire life cycle is C total It can be expressed as:

[0180] .

[0181] Multi-objective optimization algorithms include:

[0182] Based on the establishment of the aforementioned basic model, efficiency model, power model and economic model, what we need to do is to use the above multiple models to establish the objective function and perform a multi-objective optimization process, which is essentially an optimization problem.

[0183] An optimization design mathematical model mainly includes:

[0184] (1) Design variables. Design variables are mainly parameters that have an important impact on the optimization object. They should be selected carefully. If there are too many design variables, the model accuracy will be reduced; if there are too few design variables, good optimization results will not be achieved. Generally, x is used to represent the design variable. Assuming there are n design variables, it can be expressed as:

[0185] ;

[0186] (2) Objective function. The objective function is the optimization object, which is usually written as an optimization function through design variables. The objective function of multiple design variables can be written as:

[0187] ;

[0188] (3) Constraints. In the optimization process, the design variables generally have a certain design range, which is a constraint. In addition, there are some other constraints, such as size constraints, motor performance constraints, stress, strain constraints, life constraints, etc., which limit the objective function and design variables to a certain range. Constraints are generally divided into equality constraints and inequality constraints, and the expressions are as follows:

[0189] ;

[0190] Therefore, a complete mathematical model of the optimization problem is as follows:

[0191] .

[0192] Furthermore, for the gravity energy storage system, the following contents are included:

[0193] (1) Objective function

[0194] A capacity optimization model for a gravity energy storage system is established. The model takes maximizing system efficiency as the objective function. The influencing factors considered comprehensively include the total cost of building and operating and maintaining the gravity energy storage system, the cost of energy storage modules and motor equipment, and the cost of operating and maintenance technology. It is also necessary to consider maximizing the flexibility of grid adaptability, quickly respond to grid changes, and provide frequency regulation, peak regulation, voltage regulation, inertia response, and transient support services when needed. The multi-objective optimization model based on system performance and grid adaptability functions is:

[0195] ,

[0196] in, η is the efficiency of the gravity energy storage system, F is the system construction and operation and maintenance cost, and C is the adaptability to the power grid.

[0197] (2) Evaluation indicators

[0198] The grid matching rate of the gravity energy storage system can be described as the ratio of the fluctuation of the power generation output power to the power of the grid, and its expression is:

[0199] ,

[0200] Among them, D EV is the grid matching rate of the gravity energy storage system; is the average power connected to the grid; P w (t) is the power generated by the gravity energy storage system at time t; P L (t) is the power of the power grid at time t. EV Definition of D EV The smaller it is, the more the system's power generation capacity matches the grid, which has a positive effect on the objective function.

[0201] The expression of power supply reliability is:

[0202] ,

[0203] Among them, f EV P is power supply reliability; g (t) is the gravity energy storage power at time t.

[0204] (3) Constraints

[0205] 1) Power constraints for power dispatching:

[0206] ;

[0207] Among them, P L,min is the lower limit of power demand of the power grid; P L,max The upper limit of grid power demand.

[0208] 2) Gravity energy storage constraints:

[0209] ,

[0210] Among them, W sn Energy stored in the gravity energy storage system; η sn is the discharge efficiency; m is the mass of the weight; g is the acceleration of gravity; Δh is the height change; Δt is the time change; ΔW sn The energy released by the gravity energy storage system; S t , S max , S min are the storage capacity of the gravity energy storage system at time t and its maximum and minimum values; h max is the maximum height of the gravity energy storage system shaft; T t The total time the system generates electricity.

Claims

1. A vertical shaft gravity energy storage system, characterized in that: The invention comprises a vertical shaft (1), an upper warehouse (2) is arranged at the upper part of the vertical shaft (1), and a lower warehouse (3) is arranged at the lower part of the vertical shaft (1); the upper warehouse (2) has an upper warehouse conveying and loading and unloading system, and the lower warehouse (3) has a lower warehouse conveying and loading and unloading system; a derrick (11) is arranged above the vertical shaft (1); a tankway (12) and a lifting container (4) are arranged in the vertical shaft (1), and the lifting container (4) can move up and down along the tankway (12) between a wellhead platform of the upper warehouse (2) and a well bottom platform of the lower warehouse (3); The invention also includes a gravity turbine system; in one set of the gravity turbine system, the first gravity turbine sheave (51), the second gravity turbine sheave (52) and the gravity turbine friction wheel (53) are both arranged on the derrick (11); the gravity turbine friction wheel (53) is connected to the electric generator; a braking device is arranged at the gravity turbine friction wheel (53); ) and the gravity turbine friction wheel (53) are connected to the transmission with a steel wire rope (54), the two ends of the steel wire rope (54) are respectively connected to the two lifting containers (4), the lower ends of the two lifting containers (4) are connected to equal-weight tail ropes (55), and the steel wire rope (54) and the equal-weight tail ropes (55) are both multiple pieces arranged side by side; when one of the two lifting containers (4) is located at the wellhead platform of the upper warehouse (2), the other of the two lifting containers (4) is located at the well bottom platform of the lower warehouse (3); In a shaft (1), at least two lifting containers (4) of the gravity turbine systems are arranged side by side, and the two or more gravity turbine systems work in a cross-operation manner, so that the power fluctuation of the total power obtained by superimposing the power of all the gravity turbine systems meets the grid connection requirements; The upper warehouse (2) and the lower warehouse (3) both have a main lane (32) and a sub-lane (34), the main lane (32) is connected to the shaft of the vertical shaft (1), and the sub-lane (34) is a plurality of lanes arranged in parallel, and the plurality of sub-lanes (34) are respectively connected to the main lane (32) at different positions; Both the upper warehouse conveying and loading and unloading system and the lower warehouse conveying and loading and unloading system include a buffer conveyor (31), a lane mother car (33), and a lane sub-carriage (35); the buffer conveyor (31) is located in the main lane (32) and is adjacent to the shaft of the vertical shaft (1); the lane mother car (33) is located in the main lane (32) and is located between the buffer conveyor (31) and the sub-lane (34); the lane sub-carriage (35) is located in the sub-lane (34), and the sub-lane (34) has a storage rack (36), and a plurality of heavy blocks (7) are stacked on the storage rack (36) along the length direction of the sub-lane (34); One end of the sub-lane (34) away from the main lane (32) is also connected to a transfer lane (38), and a transfer mother vehicle (37) is provided in the transfer lane (38); the lane sub-vehicle (35) can be moved onto the transfer mother vehicle (37), and the transfer mother vehicle (37) can transfer the lane sub-vehicle (35) thereon to other sub-laneways (34).

2. The vertical shaft gravity energy storage system according to claim 1, characterized in that: The positions of the four lifting containers (4) of the two gravity turbine systems arranged side by side are distributed in a field shape.

3. The vertical shaft gravity energy storage system according to claim 1, characterized in that: The lifting container (4) comprises a lifting container body (41), a flow guide cover (42) is provided above the lifting container body (41), and a steel wire rope connecting device (43) for connecting a steel wire rope (54) is provided above the flow guide cover (42).

4. The vertical shaft gravity energy storage system according to claim 1, characterized in that: In the upper warehouse conveying and loading and unloading system and the lower warehouse conveying and loading and unloading system, at least the lane sub-trolley (35) is a transport vehicle (6); each transport vehicle (6) comprises a transport vehicle body (61), a vehicle-mounted conveying mechanism (62) is arranged above the transport vehicle body (61), and an anti-slip mechanism (63) is also arranged above the transport vehicle body (61), and the upper surface of the anti-slip mechanism (63) has an anti-slip portion (64); a lifting mechanism (65) is connected between the transport vehicle body (61) and the vehicle-mounted conveying mechanism (62), and / or between the transport vehicle body (61) and the anti-slip mechanism (63).

5. The vertical shaft gravity energy storage system according to claim 1, characterized in that: In the upper warehouse conveying and loading and unloading system and the lower warehouse conveying and loading and unloading system, at least the lane sub-trolley (35) is a transport vehicle (6), which also includes a vehicle track (66); each transport vehicle (6) includes a transport vehicle body (61), the bottom of the transport vehicle body (61) has main wheels (67), and the bottom of the transport vehicle body (61) is also provided with anti-rollover auxiliary wheels (68); the main wheels (67) and the anti-rollover auxiliary wheels (68) are slidably connected to the vehicle track (66) and are matched and engaged.

6. The vertical shaft gravity energy storage system according to claim 1, characterized in that: In the upper warehouse conveying and loading and unloading system and the lower warehouse conveying and loading and unloading system, at least the tunnel sub-trolley (35) and the tunnel mother car (33) are transport vehicles (6), and a weight block locking mechanism (69) is arranged above the transport vehicle (6); a locking groove (71) is arranged at the bottom of the weight block (7), and the locking groove (71) matches the shape of the weight block locking mechanism (69).

7. The vertical shaft gravity energy storage system according to claim 1, characterized in that: An overwinding and overrelease buffer device (14) is provided at a position of the vertical shaft (1) close to the upper bin (2) and the lower bin (3), and / or a hydraulic locking device is provided at a position of the vertical shaft (1) close to the upper bin (2) and the lower bin (3).

8. A method for operating a vertical shaft gravity energy storage system, characterized in that: A vertical shaft gravity energy storage system as claimed in any one of claims 1 to 7 is used; and The energy storage process includes the following steps: in a set of gravity turbine system, a lifting container (4) at the bottom platform of the well is loaded with heavy objects (7) from the lower warehouse (3), the lifting container (4) at the wellhead platform is empty, the electric generator is started, and the gravity turbine system is driven to work, so that the lifting container (4) loaded with heavy objects is raised to the wellhead platform, and the empty lifting container (4) is lowered to the bottom platform of the well, and then the two lifting containers (4) perform their respective loading and unloading work at the same time; then the above process is repeated, so that the heavy objects stored in the lower warehouse (3) are lifted one by one to the upper warehouse (2) for storage; The energy release process includes the following steps: in a set of gravity turbine system, a lifting container (4) at the wellhead platform is loaded with heavy blocks (7) from the upper warehouse (2), and the lifting container (4) at the well bottom platform is empty. The lifting container (4) loaded with heavy blocks descends to the well bottom platform under the action of gravity. This process drives the electric generator to rotate and generate electricity, while causing the empty lifting container (4) to rise to the wellhead platform. Then, the two lifting containers (4) simultaneously carry out their respective loading and unloading operations. Subsequently, the above process is repeated, and the heavy blocks stored in the upper warehouse (2) are lowered one by one to the lower warehouse (3) for storage.

9. A design method for a vertical shaft gravity energy storage system, characterized in that: A vertical shaft gravity energy storage system as claimed in any one of claims 1 to 7; comprising the following steps: Firstly, the power model, efficiency model, economic model and basic model of shaft gravity energy storage system are established respectively, and then the multi-objective optimization algorithm is optimized by using the above models to determine the best configuration and parameter combination. Among them, the power model includes the system static calculation formula: ， Among them, F j is the system static force, k is the system resistance coefficient, Q is the mass of the weight block, N2 is the number of tail ropes of equal weight, q k is the mass per unit length of the tail rope of equal weight, N1 is the number of wire ropes, p k is the mass per unit length of the wire rope, H is the depth of the shaft, g is the acceleration due to gravity, ΣM is the displacement mass of the system, and a is the acceleration of the weight block; Then, the output power is: ， Where P(t) is the output power at time t, v(t) is the speed of the weight at time t; The efficiency model includes: The gravity energy storage system converts excess electrical energy into the gravitational potential energy of heavy objects, and then converts the gravitational potential energy into electrical energy when needed. Therefore, the system efficiency can be expressed as the product of energy storage efficiency and power generation efficiency, that is: ， Among them, η cn is the energy storage efficiency, η sn For power generation efficiency; ， Among them, E q is the energy consumed by the weight to rise, η 电机 is the efficiency of the electric generator, η 变流器 is the bidirectional converter efficiency; ， Among them, E p The energy released by the falling weight; The multi-objective optimization algorithm includes the following objective functions, evaluation indicators and constraints: The objective function is a multi-objective optimization model based on system performance and grid adaptability function: ， in, η is the efficiency of the gravity energy storage system, F is the system construction and operation and maintenance cost, and C is the adaptability to the power grid; The evaluation indicators include the grid matching rate and power supply reliability of the gravity energy storage system. The expression of the grid matching rate of the gravity energy storage system is: ， Among them, D EV is the grid matching rate of the gravity energy storage system, is the average power connected to the grid, P w (t) is the power generated by the gravity energy storage system at time t, P L (t) is the power of the power grid at time t; according to D EV Definition of D EV The smaller it is, the more the system's power generation matches the grid, which has a positive effect on the objective function; The expression of power supply reliability is: ， Among them, f EV For power supply reliability, P g (t) is the gravity energy storage power at time t; The constraints include: Power dispatch power constraints, namely: ； Among them, P L,min is the lower limit of grid power demand, P L,max The upper limit of power demand of the power grid; Gravity energy storage constraints, namely: ， Among them, W sn is the energy stored in the gravity energy storage system, η sn is the discharge efficiency, m is the mass of the weight, g is the acceleration of gravity, Δh is the height change, Δt is the time change, ΔW sn is the energy released by the gravity energy storage system, S t , S max , S min are the storage capacity of the gravity energy storage system at time t and its maximum and minimum values, respectively, h max is the maximum height of the gravity energy storage system shaft, T t The total time the system generates electricity.

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