A design method of a safety protection system for a gravity energy storage system

Abstract

The application discloses a design method of a safety protection system for a gravity energy storage system, which comprises the following steps: firstly, determining system functions; then, determining system architecture and configuring system hardware; and then, sequentially designing fault analysis diagnosis functions, safety level judgment functions, protection object judgment functions and shutdown logic functions. The application provides a design method of a safety protection system for a gravity energy storage system, which can guarantee the safety of the operation of the gravity energy storage system through four function module units of fault analysis diagnosis functions, safety level judgment functions, protection object judgment functions and shutdown logic functions, prevent safety accidents from occurring from the software level, and guarantee that the gravity energy storage system can operate safely and effectively.

Description

TECHNICAL FIELD

[0001] The application relates to a design method of a safety protection system of a gravity energy storage system and belongs to the technical field of gravity energy storage. BACKGROUND

[0002] With the research and vigorous development of new energy and renewable energy by the country, seeking an advanced method for improving energy utilization rate has become a primary concern in the industry. At present, configuring an energy storage system is one of the most effective methods for improving the utilization rate of new energy, and among various energy storage methods, gravity energy storage has its unique technical advantages.

[0003] Since a gravity energy storage project needs to lift heavy objects to a high place for energy storage, and the heavy objects themselves have huge mass. In the process of transporting the heavy objects, if a fault occurs and the heavy objects accidentally fall, a serious safety accident will be caused. Therefore, it is necessary to design a safety protection system of a gravity energy storage system to ensure the safe and effective operation of the gravity energy storage system. SUMMARY

[0004] The application aims to provide a design method of a safety protection system of a gravity energy storage system to ensure the safe and effective operation of the gravity energy storage system.

[0005] To solve the above technical problems, the technical solution adopted by the application is:

[0006] A design method of a safety protection system of a gravity energy storage system, characterized by comprising the following steps:

[0007] S1, determination of system functions, the system functions including fault analysis and diagnosis function, safety level judgment function, protection object judgment function and shutdown logic function;

[0008] S2, determination of system architecture and system hardware configuration;

[0009] S3, design of the fault analysis and diagnosis function, all electrical fault signals and state quantity feedbacks of the moving mechanisms in the system are read into the safety protection system, the electrical fault signals are directly read by the PLC and used as the input of the fault analysis and diagnosis, and the mechanical faults are judged by single or multiple state quantity feedbacks and used as the input of the mechanical fault analysis and diagnosis;

[0010] S4, design of the safety level judgment function, a safety fault database is established, the fault data in the safety fault database are classified according to the safety level, the safety protection system sends the faults analyzed and diagnosed by the safety protection system to the safety fault database for comparison, determines the safety level of the faults, and finally feeds back the safety level to the PLC;

[0011] S5, the protection object judgment function is designed, according to the safety level and the alarm signal associated with the safety level, the protection object and the protection range are judged by PLC;

[0012] S6, the stop logic function is designed, the stop sequence control program is designed to make the equipment stop in a safe order, after the protection object and the protection range are judged, the stop sequence control program is called by PLC.

[0013] Further, in the step S2, the system architecture of the safety protection system is sequentially divided into system layer, unit layer and mechanism layer from top to bottom, the system layer is used for the determination of the protection object, the unit layer and the mechanism layer are used for fault analysis and diagnosis, safety level judgment and stop logic execution.

[0014] Further, in the step S2, the system hardware configuration of the safety protection system includes PLC system and supporting input and output devices, and a host computer is configured in the control room to control the operation strategy of the safety protection system.

[0015] Further, the step S3 is specifically:

[0016] 3.1, establish a safety fault database: collate the electrical fault signals and state quantity feedbacks related to system safety of the gravity energy storage system, and establish a safety fault database for the electrical fault signals and state quantity feedbacks, so that the PLC program can be called subsequently;

[0017] 3.2, fault signal reading: the electrical fault signals and state quantity feedbacks of each mechanism are called in the PLC system program of the unit layer, the calling logic is established in the safety protection system, and the electrical fault signals and state quantity feedbacks in the safety fault database in the unit layer are read into the calling logic;

[0018] 3.3, fault analysis and diagnosis: the electrical fault signals can be directly read and the fault condition is judged, so the electrical fault signals are directly used as the result of analysis and diagnosis; mechanical faults include two categories of mechanical structure damage and hydraulic system failure, and the specific fault type is determined after the related one or more state quantity feedbacks are compared.

[0019] Further, the step S4 is specifically:

[0020] 4.1 Preset Safety Levels: First, based on the severity of the hazard impact in the safety fault database, four safety fault levels are preset. These four levels include directly causing the gravity block to fall, causing the gravity block to have a risk of falling, causing damage to the main equipment, and causing an electrical fire. The severity of the hazard impact is quantified, and weights are assigned to the four safety fault levels, labeled L1 to L4 sequentially. L1 to L4 are expressed as percentages, and L1 + L2 + L3 + L4 = 100%.

[0021] 4.2 Fault Classification Calculation: Each fault in the safety fault database is classified according to its potential safety consequences. The safety consequences of a fault are divided into four levels, with the probability of occurrence for each level denoted as Q1 to Q4, respectively. The specific safety level of the fault is obtained by multiplying the probability by its weight. The formula for calculating the safety level Q is as follows: Q = ∑Q n ×L n =Q1×L1+Q2×L2+Q3×L3+Q4×L4;

[0022] 4.3 Security Level Matching: The security level value Q of each fault in the security fault database is calculated. The fault analysis and diagnosis function determines the faults existing in the current security protection system and the corresponding security level value Q of the fault.

[0023] Furthermore, in step 4.1, the weights of the four levels of safety faults are set as follows: L1=35%, L2=30%, L3=20%, L4=15%.

[0024] Furthermore, in step S5, the faults are divided into safe faults and non-safe faults, wherein safe faults are divided into four levels according to the safety level.

[0025] Furthermore, the shutdown sequence control procedure in step S6 includes three levels: shutdown of a single device, shutdown of a single energy storage unit, and shutdown of the energy storage system.

[0026] A stop command is issued by the PLC to stop a single piece of equipment.

[0027] The shutdown of a single energy storage unit consists of the following steps: status assessment, disconnection of the power source of the lifting device, braking of the lifting device, stopping the drive motor of the horizontal device, opening the pressure relief valve of the hydraulic system of the horizontal device, and stopping the top trolley.

[0028] An energy storage system consists of several energy storage units. Compared with the energy storage unit logic, the shutdown logic of the energy storage system requires an additional step of determining the number of energy storage units to be shut down before executing the energy storage unit logic.

[0029] Further, the stop sequence control program further comprises a lifting device returning to the first layer and a gravity block nearby arrangement logic, and the lifting device returning to the first layer and the gravity block nearby arrangement logic specifically comprises: judging the gravity block arrangement situation in the energy storage unit by the safety protection system, automatically selecting a layer with spare arrangement space and normal horizontal device according to the gravity block quantity of the object layer and the corresponding horizontal device fault condition, automatically judging the movement distance of the lifting device by comparing the normal layer and the current layer number, and automatically moving the lifting device to the corresponding layer, placing the gravity block, and then executing the returning to the first logic to make the lifting device return to the first layer.

[0030] Compared with the prior art, the present application has the following advantages and effects:

[0031] 1. The present application provides a design method of a safety protection system for a gravity energy storage system, which can ensure the safe operation of the gravity energy storage system by four function modules, i.e., a fault analysis diagnosis function, a safety level judgment function, a protection object judgment function and a stop logic function, to prevent safety accidents from occurring and ensure the safe and effective operation of the gravity energy storage system from the software level.

[0032] 2. The present application can accurately diagnose the type of specific fault, classify the corresponding fault and quantitatively process the possible consequences of the corresponding fault, so that the fault can be accurately judged and processed.

[0033] 3. The present application can safely and reliably ensure the efficiency of system operation, accurately lock the protection range, design the stop logic of the device in the optimal order, and maximize the efficient operation of the system. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a flowchart of a design method of a safety protection system for a gravity energy storage system of the present application.

[0035] Figure 2 is a flowchart of a stop logic of a gravity energy storage system of the present application. DETAILED DESCRIPTION

[0036] In order to clearly and completely describe the technical solutions adopted by the present application to achieve the predetermined technical purposes, the technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments, and the technical means or technical features in the embodiments of the present application can be replaced without creative labor. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0037] As Figure 1As shown, the design method of a safety protection system for a gravity energy storage system of the present application comprises the following steps:

[0038] S1, determination of system functions, including fault analysis and diagnosis function, safety level judgment function, protection object judgment function and shutdown logic function.

[0039] The main equipment of the gravity energy storage system includes electric motor / generator, power shaft, moving mechanism and electrical control equipment. Among them, except for the electrical control equipment, the rest of the equipment participates in the moving operation of the gravity block. Therefore, the failure of these devices may cause the deviation or falling of the gravity block.

[0040] The main faults of the gravity energy storage equipment can be divided into electrical faults and mechanical faults. The electrical faults can be directly transmitted by signals, and the control system can directly read the electrical fault signals. The mechanical faults need one or more state feedbacks as the basis for judgment. Therefore, the primary function of the gravity energy storage safety protection system is the fault analysis and diagnosis function.

[0041] The gravity energy storage system has a large number of equipment, and the fault types and fault numbers are also very large. Some of these faults can cause safety hazards, but some of these faults will not cause safety hazards. Among the faults that have safety hazards, there are also multiple safety levels. The highest safety level requires the entire gravity energy storage system to be stopped immediately. Some faults only need to be removed from the current unit, and the entire system will continue to operate. Therefore, the second function of the gravity energy storage safety protection system is the safety level judgment function.

[0042] After the safety impact level of the fault is determined, the safety protection system needs to determine the safety protection object according to the determined safety level, i.e. the equipment or system that needs to be stopped. Therefore, the third function of the gravity energy storage system safety protection system is the protection object judgment function.

[0043] The gravity energy storage system is composed of multiple energy storage units, and the energy storage unit is composed of multiple devices and structural frames. Therefore, the gravity energy storage is a very complex system. Its normal start and stop must follow a certain order to start and stop each device. When a safety fault occurs in the gravity energy storage system, the devices must be stopped in a certain order. Therefore, the fourth function of the gravity energy storage system safety protection system is the function of automatically executing the shutdown logic.

[0044] S2, system architecture determination and system hardware configuration.

[0045] The gravity energy storage safety protection system is integrated in the gravity energy storage control system, that is, the controller and the input and output devices are shared with the control system. Therefore, the system architecture of the safety protection system is sequentially divided into a system layer, a unit layer and a mechanism layer from top to bottom, the system layer is used for determining the protection object, and the unit layer and the mechanism layer are used for fault analysis and diagnosis, safety level judgment and shutdown logic execution.

[0046] The system hardware configuration of the safety protection system includes a PLC system and a supporting input and output device, and a host computer is arranged in the central control room to control the operation strategy of the safety protection system.

[0047] Specifically, the main hardware configuration in the mechanism layer control cabinet is as follows: a PLC input and output module, a PLC remote I / O module and an optical-electricity switch. The fault alarm or abnormal signal of the device body is collected through the PLC input and output module, and is forwarded to the upper-level PLC system through the PLC remote I / O module, wherein the optical-electricity switch converts the electrical signal into an optical signal to ensure reliable output at a long distance.

[0048] The hardware configuration of the unit layer is similar to that of the system layer: an optical-electricity switch and a PLC controller. The optical signal is converted into an electrical signal through the optical-electricity switch and is connected to the PLC controller for logical judgment.

[0049] S3, the fault analysis and diagnosis function design, the electrical fault signals and state quantity feedbacks of all the mechanisms in the system are read into the safety protection system, the electrical fault signals are directly read by the PLC and used as the input of the fault analysis and diagnosis, and the mechanical faults are judged by single or multiple state quantity feedbacks and used as the input of the mechanical fault analysis and diagnosis.

[0050] 3.1, establish a safety fault database: there are many electrical faults in the gravity energy storage system, only a part of which is related to safety, therefore, the electrical fault signals and state quantity feedbacks related to the safety of the gravity energy storage system are sorted out, and these electrical fault signals and state quantity feedbacks are established into a safety fault database for subsequent PLC program calling;

[0051] The safety fault database can be established by using software such as SQL, and the database is preset with fault signals related to safety. The mechanical faults are associated with the signals in the database for subsequent diagnosis.

[0052] 3.2, fault signal reading: the electrical fault signals and state quantity feedbacks of each mechanism are called in the PLC system program of the unit layer, and the calling logic is established in the safety protection system to read the electrical fault signals and state quantity feedbacks in the safety fault database in the unit layer into the calling logic; when the PLC controller receives the fault signal, the database information is called to check whether the received fault signal matches the database through the query function.

[0053] 3.3, Fault analysis diagnosis: electrical fault signals can be directly read and determine the fault condition, such as motor failure, power failure, frequency converter failure, etc., so the electrical fault signal is directly used as the result of analysis and diagnosis.

[0054] Mechanical failure includes two categories of mechanical structure damage and hydraulic system failure. The specific failure type is determined by the feedback of one or more related state quantities after comprehensive comparison. For example, the horizontal wheel is worn out due to long-term operation. The horizontal car travels the same number of laps, and the distance of the horizontal car will be shortened with the severity of wear and tear. The specific fault can be judged according to the pulse signal of the encoder and the positioning feedback of the horizontal car track.

[0055] According to the same principle, the type of mechanical failure can be diagnosed by comparing a plurality of state quantity feedbacks. After diagnosing the fault condition, the fault signal is compared with the safety level in the database to determine the safety level of the fault. The main comparison parameters are the related fault signals, or the limits and trends of the related state quantities. As long as the fault definition in the fault database is met, it can be used as the basis for fault diagnosis.

[0056] S4, Safety level judgment function design, establish safety fault database, classify the fault data in the safety fault database according to the safety level, the safety protection system sends the fault analyzed and diagnosed by the safety protection system to the safety fault database for comparison, determines the safety level of the fault, and finally feeds back the safety level to the PLC execution protection object judgment.

[0057] 4.1, Preset safety level: first, according to the severity of the harm and impact, the safety fault is preset to four levels in the safety fault database, the four levels of safety fault include directly causing the gravity block to fall, causing the gravity block to have the risk of falling, causing the main equipment to be damaged, and causing the electrical fire; The severity of the harm and impact is quantified, and the weights of the four levels of safety fault are set, respectively, and L1~L4 are sequentially identified, wherein L1~L4 is expressed by percentage, and L1+L2+L3+L4=100%; The weights of the four levels of safety fault are respectively set as: L1=35%, L2=30%, L3=20%, L4=15%. The weight can be adjusted according to the actual situation.

[0058] 4.2, Fault classification calculation: each fault in the safety fault database is classified and calculated according to its safety consequences, the safety consequences caused by a fault are classified into four levels, and the probabilities of the four levels are sequentially represented by Q1~Q4. The value of the specific safety level of the fault is obtained by multiplying the probability by the weight. The calculation formula of the safety level value Q is as follows: Q=∑Q n ×L n= Q1 x L1 + Q2 x L2 + Q3 x L3 + Q4 x L4; the probability Q1-Q4 of each level is determined by: through the prototype test of the moving mechanism of the gravity energy storage system, the probability of each fault leading to safety consequences is statistically determined through a large number of tests.

[0059] For example, the brake failure of the lifting device is tested by a prototype, and the probability of causing the gravity block to fall is Q1=75%, the probability of causing the gravity block to have a falling risk is Q2=10%, the probability of causing a fire is Q3=10%, and the probability of causing an electrical safety failure is Q4=5%. According to the preset safety level weights of the project, L1=35%, L2=30%, L3=20%, and L4=15%; and according to the safety level value calculation formula, the safety level of the brake failure of the lifting device is:

[0060] Q= Q1 x L1 + Q2 x L2 + Q3 x L3 + Q4 x L4=75% x 35% +10% x 30% +10% x 20% +5% x 15%=32%.

[0061] 4.3, safety level matching: the safety level value Q of each fault in the safety fault database is calculated, and the safety level value Q of the corresponding fault is determined by the fault analysis and diagnosis function when the current safety protection system exists.

[0062] S5, protection object judgment function design, according to the fault safety level and the alarm signal associated with the fault safety level, the protection object and the protection range are determined by the PLC. The fault is divided into safety fault and non-safety fault, wherein the safety fault is divided into four levels according to the safety level.

[0063] Taking the horizontal trolley as an example, the hydraulic system cooling fan fails, which causes the temperature of the hydraulic system of the horizontal trolley to rise, but does not affect the normal operation of the horizontal trolley. Therefore, in the design of the protection object judgment function, according to the fault safety level and the alarm signal associated with the fault safety level, the protection object and the protection range are determined by the PLC system.

[0064] The main purpose of this function is to automatically determine the system removal range when the safety protection system diagnoses the current fault. First, the fault is divided into safety fault and non-safety fault, wherein the safety fault is divided into several cases according to the safety level.

[0065] S6, stop logic function design, design stop sequence control program to make the equipment stop in a safe order, and after determining the protection object and the protection range, the stop sequence control program is called by the PLC.

[0066] The shutdown sequence control program includes three levels: single device shutdown, single energy storage unit shutdown, and energy storage system shutdown.

[0067] The single device shutdown sends a stop command through the PLC to stop the single device.

[0068] The single energy storage unit shutdown includes the following steps: state judgment, cutting off the power source of the lifting device, braking the lifting device, stopping the horizontal device drive motor, opening the horizontal device hydraulic system pressure relief valve, and stopping the top trolley.

[0069] As shown in Figure 2 The energy storage system is composed of several energy storage units, and the energy storage system shutdown logic needs to add a step of judging the number of energy storage units before executing the energy storage unit logic.

[0070] In the motion mechanism device stop logic, the drive system is stopped first, and the hydraulic system is stopped after the motion mechanism completely stops moving and reaches a safe position.

[0071] In the energy storage unit stop logic, according to the system operation strategy, if the horizontal car fails, the faulty horizontal car and the corresponding layer of horizontal cars are stopped first to ensure efficiency priority; during normal operation, to ensure system safety performance, when any motion mechanism in the energy storage unit fails, the entire energy storage unit is stopped. The specific shutdown strategy is determined according to the system operation strategy.

[0072] In the system stop logic, if a certain energy storage unit fails, the unit is cut off, the operation strategy is adjusted, and the other energy storage units continue to operate.

[0073] The shutdown logic should ensure that the gravity energy storage shutdown logic is more secure than the conventional shutdown protection logic.

[0074] The shutdown sequence control program also includes the lifting device returning to the first layer and the gravity block being arranged nearby. Since the lifting device may be in a loaded state during an emergency stop, to ensure safety, after similar situations occur, the lifting device returning to the first layer and the gravity block being arranged nearby logic needs to be added after the shutdown logic is executed. The lifting device returning to the first layer and the gravity block being arranged nearby logic specifically includes: the safety protection system judges the arrangement of the gravity block in the energy storage unit, according to the number of gravity blocks on the target layer and the corresponding horizontal device failure condition, automatically selects a layer with spare arrangement space and normal horizontal device, and the lifting device automatically judges the movement distance by comparing the normal layer and the current layer number, so that the lifting device automatically moves to the corresponding layer, places the gravity block, and then executes the first return logic to make the lifting device return to the first layer.

[0075] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical contents without departing from the technical solution of the present application, and can make equivalent embodiments with equivalent changes, as long as they do not depart from the technical solution of the present application and are within the spirit and principle of the present application. Any simple modification, equivalent replacement and improvement of the above embodiments, as long as they are within the protection scope of the present application, are still within the protection scope of the present application.

Claims

1. A method of designing a safety protection system for a gravitational energy storage system, characterized in that Comprising the following steps: S1, determination of system functions, including fault analysis and diagnosis function, safety level judgment function, protection object judgment function and shutdown logic function; S2, system architecture determination and system hardware configuration; S3, fault analysis and diagnosis function design, reading all electrical fault signals and state quantity feedback of the moving mechanism in the system into the safety protection system, the electrical fault signals are directly read by PLC and used as the input of fault analysis and diagnosis, mechanical faults are judged by single or multiple state quantity feedback and used as the input of mechanical fault analysis and diagnosis; S4, safety level judgment function design, establishing a safety fault database, classifying the fault data in the safety fault database according to the safety level, sending the fault analyzed by the safety protection system to the safety fault database for comparison to determine the safety level of the fault, and finally feeding back the safety level to the PLC; S5, protection object judgment function design, determining the protection object and protection range according to the fault safety level and the alarm signal associated with the fault safety level; S6, shutdown logic function design, designing a shutdown sequence control program to make the equipment stop in a safe order, and calling the shutdown sequence control program by PLC after determining the protection object and protection range.

2. The method of designing a safety protection system for a gravitational energy storage system according to claim 1, wherein: In the step S2, the system architecture of the safety protection system is divided into system layer, unit layer and moving mechanism layer from top to bottom, the system layer is used for protection object determination, and the unit layer and moving mechanism layer are used for fault analysis and diagnosis, safety level judgment and shutdown logic execution.

3. The method of designing a safety protection system for a gravitational energy storage system according to claim 1, wherein: In the step S2, the system hardware configuration of the safety protection system includes PLC system and supporting input and output devices, and a host computer is configured in the control room to control the operation strategy of the safety protection system.

4. The method of designing a safety protection system for a gravitational energy storage system according to claim 1, wherein: The step S3 is specifically: 3.1, establishing a safety fault database: sorting the electrical fault signals and state quantity feedback related to system safety of the gravity energy storage system, and establishing a safety fault database for these electrical fault signals and state quantity feedback for subsequent PLC program calling; 3.2, fault signal reading: calling the electrical fault signals and state quantity feedback of each moving mechanism in the PLC system program of the unit layer, and establishing a calling logic in the safety protection system to read the electrical fault signals and state quantity feedback in the safety fault database in the unit layer into the calling logic; 3.3, fault analysis and diagnosis: electrical fault signals can be directly read and fault conditions can be judged, so electrical fault signals are directly used as the result of analysis and diagnosis; mechanical faults include mechanical structure damage and hydraulic system failure, and the specific fault type of mechanical faults is determined after comprehensive comparison according to one or more related state quantity feedbacks.

5. The method of designing a safety protection system for a gravitational energy storage system according to claim 1, wherein: The step S4 is specifically: 4.1, preset safety level: first, according to the severity of the hazard impact, the safety fault is preset to four levels in the safety fault database, the four levels of safety fault include directly causing the gravity block to fall, causing the gravity block to have the risk of falling, causing the main equipment to be damaged, and causing electrical fire; The severity of the hazard impact is quantified, and weights are set for the four levels of safety failure, respectively, with L1-L4 being sequentially identified, wherein L1-L4 are expressed in percentages, and L1+L2+L3+L4=100%; 4.2, fault classification calculation: each fault in the security fault database is classified and calculated according to the security consequences it will cause, the security consequences caused by a fault are divided into four levels, and the probabilities of the occurrence of the four levels are represented by Q1-Q4 in turn, the numerical value of the specific security level of the fault is obtained by multiplying the probability by the weight, and the calculation formula of the numerical value Q of the security level is as follows: Q=∑Q n ×L n =Q1×L1+Q2×L2+Q3×L3+Q4×L4; 4.3, safety level matching: by calculating the safety level value Q of each failure in the safety failure database, the safety failure analysis and diagnosis function judges the safety level value Q of the corresponding failure while judging the existing failure of the current safety protection system.

6. The method of designing a safety protection system for a gravitational energy storage system according to claim 5, wherein: In step 4.1, the weights of the four levels of safety failure are set as: L1=35%, L2=30%, L3=20%, and L4=15%.

7. The method of designing a safety protection system for a gravitational energy storage system according to claim 1, wherein: In step S5, the failure is divided into safety failure and non-safety failure, wherein the safety failure is divided into four levels according to the safety level.

8. The method of designing a safety protection system for a gravitational energy storage system according to claim 1, wherein: The shutdown sequence control program in step S6 includes three levels: single device shutdown, single energy storage unit shutdown, and energy storage system shutdown. Single device shutdown sends a stop command through PLC to stop the single device; Single energy storage unit shutdown includes the following steps: state judgment, cutting off the power source of the lifting device, braking the lifting device, stopping the horizontal device driving motor, opening the horizontal device hydraulic system pressure relief valve, and stopping the top trolley; The energy storage system is composed of several energy storage units, and the energy storage system shutdown logic needs to add one step of energy storage unit quantity judgment logic before executing the energy storage unit logic.

9. The method of designing a safety protection system for a gravitational energy storage system according to claim 8, wherein: The shutdown sequence control program also includes lifting device returning to the first layer and gravity block arranging near logic, which is specifically: the safety protection system judges the arrangement of the gravity block in the energy storage unit, automatically selects a layer with spare arrangement space and normal horizontal device according to the number of gravity blocks on the object layer and the corresponding horizontal device failure condition, and the lifting device automatically judges the movement distance by comparing the normal layer with the current layer number, so as to automatically move the lifting device to the corresponding layer, place the gravity block, and then execute the returning to the first layer logic to make the lifting device return to the first layer.

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