Multi-stage protection and controlled bleed control method and system for compressed air energy storage power plants

Abstract

The present application belongs to compressed air control technical field, especially relates to compressed air energy storage power station multistage protection and controlled release control method and system. Including: build compressed air energy storage power station system including release bypass and set release valve and safety valve in release bypass downstream;When pressure abnormality occurs, enter first response, adjust the operating parameters of compressed air energy storage power station system, or superimposed opening release bypass, suppress the pressure abnormality trend;When first response cannot suppress pressure abnormality, enter second response, adjust the opening of release valve, carry out gas release;When second response cannot suppress pressure abnormality, enter third response, adopt ladder type release sequence, increase the opening of release valve and gradually increase the opening of safety valve for gas release, and finally release through triggering the burst disc. The present application avoids the disadvantages of single protection device protection means single and easy overactive protection through ladder type control strategy.

Description

Technical Field

[0001] This invention belongs to the field of compressed air energy storage control technology, and particularly relates to a multi-level protection and controlled discharge control method and system for compressed air energy storage power stations. Background Technology

[0002] Compressed air energy storage (CAES) is an important large-scale physical energy storage technology. Its basic principle is to use electricity to compress air and store it in underground caverns (such as salt caverns or abandoned mines) or large pressure vessels during periods of surplus electricity, i.e., periods of low electricity demand. During periods of high electricity demand, the high-pressure air is released and heated to drive an expansion generator to generate electricity, thereby achieving peak shaving and frequency regulation of the power grid.

[0003] During the actual operation of a CAES power plant, the gas storage unit and its connected pipelines, valves, and other pressure-bearing components face complex dynamic loads and transient flow conditions. In particular, under certain extreme conditions, the system pressure may change drastically, posing a serious threat to equipment safety.

[0004] In existing technologies, overpressure protection for CAES systems commonly employs safety valves or rupture discs as the final safety barrier. These devices typically activate when the pressure reaches a preset limit, rapidly releasing a large amount of gas through a single opening or rupture to prevent the system pressure from exceeding the maximum permissible working pressure (MAWP). However, this single, passive protection method suffers from problems such as venting impact and secondary hazards, significant energy loss, and the need for refilling before power is restored, resulting in a lengthy process and unsuitability for complex and variable pressure environments. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a multi-level protection and controlled discharge control method and system for compressed air energy storage power stations. When the system detects extreme conditions such as abnormal pressure rise or drop, it can achieve an orderly, controllable, and stable transition from early warning and intervention to final protection through the synergistic effect of rapid cut-off, flow restriction, and graded discharge sequence, and through multi-level hierarchical response measures. This effectively avoids system equipment overload, reduces ineffective high-pressure air emissions and energy waste, and prevents secondary hazards caused by instantaneous large-flow discharge.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0007] The first aspect of this invention provides a multi-level protection and controlled discharge control method for compressed air energy storage power stations.

[0008] A multi-level protection and controlled discharge control method for compressed air energy storage power stations includes the following steps:

[0009] Construct a compressed air energy storage power station system that includes a discharge bypass and a discharge valve and safety valve located downstream of the discharge bypass;

[0010] Monitor the pressure value of the compressed air energy storage power station system to determine if any pressure abnormalities occur;

[0011] When abnormal pressure occurs, a tiered response mechanism is adopted:

[0012] Enter Level 1 response, adjust the operating parameters of the compressed air energy storage power station system, or activate the discharge bypass to suppress abnormal pressure trends;

[0013] When the first-level response fails to suppress the pressure abnormality, the second-level response is initiated, and the opening of the relief valve is adjusted to release the gas.

[0014] When the Level 2 response fails to suppress the pressure anomaly, it enters the Level 3 response, adopting a stepped release sequence. While increasing the opening of the release valve, the opening of the safety valve is gradually increased to release the gas. When the release valve and the safety valve fail to suppress the pressure anomaly, the final release is achieved by triggering the rupture disc for a one-time, full-range final release.

[0015] The second aspect of the present invention provides a multi-level protection and controlled discharge control system for a compressed air energy storage power station.

[0016] A multi-level protection and controlled discharge control system for compressed air energy storage power stations, including:

[0017] The system setup module is configured to: build a compressed air energy storage power station system including a discharge bypass and a discharge valve and a safety valve located downstream of the discharge bypass;

[0018] The pressure anomaly detection module is configured to monitor the pressure value of the compressed air energy storage power station system and determine whether a pressure anomaly has occurred.

[0019] The tiered response module is configured to implement a tiered response mechanism when an abnormal pressure occurs.

[0020] Enter Level 1 response, adjust the operating parameters of the compressed air energy storage power station system, or activate the discharge bypass to suppress abnormal pressure trends;

[0021] When the first-level response fails to suppress the pressure abnormality, the second-level response is initiated, and the opening of the relief valve is adjusted to release the gas.

[0022] When the Level 2 response fails to suppress the pressure anomaly, it enters the Level 3 response, adopting a stepped release sequence. While increasing the opening of the release valve, the opening of the safety valve is gradually increased to release the gas. When the release valve and the safety valve fail to suppress the pressure anomaly, the final release is carried out in one go by triggering the rupture disc.

[0023] This invention provides a multi-level protection and controlled discharge control method and system for compressed air energy storage power stations, which can achieve the following technical effects:

[0024] 1. Multi-level response, balancing safety and efficiency: A tiered control strategy of "early warning - flow limiting - controlled discharge - ultimate protection" avoids the drawbacks of single protection devices and methods, which are prone to over-protection. Intervention in the early stages of pressure anomalies prevents escalation and, through precise control of discharge flow and rate, minimizes unnecessary energy loss, improves system availability, and reduces handling costs.

[0025] 2. Recoverable operation, reducing downtime losses: Under non-extreme overpressure conditions, controlled venting is prioritized using reclosable regulating valves. Once the pressure returns to normal, the valves can be quickly closed to restore operation, shortening recovery time and avoiding the need for frequent resets after safety valve trips or replacements after rupture disc breakage. This significantly reduces maintenance costs and downtime.

[0026] 3. Systematic interlocking control with high reliability: The control module coordinates the sequential action of the main shut-off valve and the multi-stage relief device, ensuring that the gas charging and discharging path is reliably isolated in an emergency (the main shut-off valve closing time does not exceed 1 second), and can release pressure in an orderly manner, effectively preventing secondary failures such as pressure reversal and equipment surge.

[0027] 4. Significantly reduces secondary risks: The step-by-step and controlled release method allows for control of the release flow rate and speed, thereby greatly mitigating the enormous noise, backlash, pipeline vibration, and potential low-temperature hazards caused by instantaneous large-flow release, and improving overall safety.

[0028] 5. Intelligence and Automation: Based on ESD logic (electrostatic discharge protection logic), the automatic judgment and hierarchical execution mechanism can respond to extreme working conditions in milliseconds without relying on manual judgment and operation, reducing the risk of human error and ensuring the timeliness and accuracy of the response.

[0029] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0031] Figure 1 This is a flowchart of the method in Example 1.

[0032] Figure 2 This is a structural diagram of a compressed air energy storage power station system, as shown in Example 1.

[0033] The attached diagram lists the components represented by each number as follows:

[0034] 1. Compressor; 2. Gas storage cavity; 3. Low-pressure buffer tank; 4. Expansion generator; 5. Control system; 6. Power grid; 7. Main shut-off valve; 8. Compressor outlet pressure detection module; 9. Gas storage cavity pressure detection module; 10. Gas storage cavity outlet pressure detection module; 11. Bypass valve; 12. Relief valve; 13. Rupture disc; 14. Safety valve; 15. Electrical load; 16. Main gas pipeline; 17. Relief bypass. Detailed Implementation

[0035] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0037] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0038] Example 1

[0039] like Figure 1 As shown in this embodiment, the multi-level protection and controlled discharge control method for compressed air energy storage power stations includes the following steps:

[0040] A compressed air energy storage power station system is constructed, including a discharge bypass 17 and a discharge valve 12 and a safety valve 14 located downstream of the discharge bypass 17.

[0041] Monitor the pressure value of the compressed air energy storage power station system to determine if any pressure abnormalities occur;

[0042] When abnormal pressure occurs, a tiered response mechanism is adopted:

[0043] Enter Level 1 response, adjust the operating parameters of the compressed air energy storage power station system, or activate the discharge bypass 17 to suppress abnormal pressure trends.

[0044] When the first-level response fails to suppress the pressure abnormality, the second-level response is initiated, and the opening of the relief valve 12 is adjusted to release the gas.

[0045] When the secondary response fails to suppress the pressure anomaly, the tertiary response is initiated, employing a stepped release sequence. While increasing the opening of the release valve 12, the opening of the safety valve 14 is gradually increased to release the gas. When the release valve 12 and the safety valve 14 fail to suppress the pressure anomaly, the final release is achieved by triggering the rupture disc 13 for a one-time, full-range final release.

[0046] When the system detects extreme conditions such as abnormal pressure rise or drop, the method in this embodiment is adopted. Through the synergistic effect of rapid cut-off, flow restriction and graded discharge sequence (integrated into the emergency shutdown system), an orderly, controllable and smooth transition from early warning and intervention to final protection is achieved. This effectively avoids system equipment overload, reduces ineffective discharge of high-pressure air and waste of electricity, and prevents secondary hazards caused by instantaneous large flow discharge.

[0047] The method of this embodiment will now be explained in detail with reference to the accompanying drawings.

[0048] Figure 2 This is a structural diagram of the compressed air energy storage power station system in this embodiment. Figure 2 As shown, the structure of the compressed air energy storage power station system is as follows:

[0049] A main gas pipeline 16 is installed between the compressor 1, the gas storage cave 2 and the expansion generator 4;

[0050] A venting bypass 17 is installed on the main gas pipeline 16 between the gas storage cave 2 and the expansion generator 4. The end of the venting bypass 17 is connected to the low-pressure buffer tank 3, and a bypass valve 11 is installed on the venting bypass 17.

[0051] A vent valve 12, a safety valve 14, and a rupture disc 13 are installed on the main gas pipeline 16 downstream of the vent bypass 17.

[0052] A main shut-off valve 7 is installed on the intake pipe of compressor 1;

[0053] A compressor outlet pressure detection module 8 is installed on the main gas pipeline 16 at the outlet of compressor 1, a gas storage cave outlet pressure detection module 10 is installed at the outlet of gas storage cave 2, and a gas storage cave pressure detection module 9 is installed inside gas storage cave 2.

[0054] It can be understood that it also includes control system 5, which is connected to compressor 1, expander generator 4, compressor outlet pressure detection module 8, gas storage cave pressure detection module 9, gas storage cave outlet pressure detection module 10, bypass valve 11, relief valve 12, safety valve 14 and rupture disc 13 by signal respectively.

[0055] It also includes power grid 6 and electrical load 15, with power grid 6 supplying power to electrical load 15.

[0056] Figure 2In the diagram, long dashed lines represent signal lines; short dashed lines represent power transmission lines. Figure 2 The functions of the middle component are described in detail below:

[0057] Compressor 1: Responsible for pressurizing gas into gas storage cavern 2, and storing energy during off-peak electricity demand;

[0058] Storage Cave 2: Used to store compressed air;

[0059] Low-pressure buffer tank 3: Used to initially release and depressurize the high-pressure air in the gas storage cave 2, thus playing a buffering role;

[0060] Expander Generator 4: It generates electricity by driving the impeller to rotate with compressed air, supporting electricity consumption during peak periods;

[0061] Control system 5: Receives information from sensors and transmits commands to valves at all levels to control the pressure release;

[0062] Power grid 6: responsible for supplying power to compressor 1 and compressing air during off-peak hours; during peak hours, it is supported by the impeller of expansion generator 4 for power generation.

[0063] Main shut-off valve 7: Responsible for cutting off the air supply under extreme operating conditions to ensure pressure relief;

[0064] Compressor outlet pressure detection module 8: Used to detect the pressure at the outlet of compressor 1;

[0065] Gas storage cavern pressure detection module 9: Used to detect the pressure in the gas storage cavern;

[0066] Gas storage cave outlet pressure detection module 10: used to detect the pressure at the outlet of the gas storage cave;

[0067] Bypass valve 11: is the valve connecting the main gas pipeline 16 and the low-pressure buffer tank 3;

[0068] Relief valve 12: Responsible for pressure relief during the second-level response phase and the first stage of the third-level response;

[0069] Safety valve 14: Responsible for pressure relief in the second stage of a three-level response;

[0070] Fracturing fragment 13: Responsible for pressure relief in the third phase of a Level 3 response.

[0071] The multi-level protection and controlled discharge control method in this embodiment specifically includes the following steps:

[0072] 1. Anomaly detection and early warning stage.

[0073] Monitoring the pressure values ​​of the compressed air energy storage power station system to determine if any pressure anomalies occur, specifically including:

[0074] Pressure sensors are installed in the compressed air energy storage power station system. The pressure sensors are installed at key pipeline nodes and the inlet and outlet of the air storage cave 2.

[0075] Obtain the pressure value returned by the pressure sensor;

[0076] The pressure value is compared with a preset safety threshold. When the rate of pressure change exceeds the first-level response pressure rate threshold and / or the pressure value exceeds the first-level response pressure threshold, a pressure anomaly is determined, and a first-level response is initiated.

[0077] This embodiment uses pressure sensors, temperature sensors, and flow monitoring devices placed at the inlet and outlet of the gas storage chamber and key pipeline nodes to collect system operating parameters in real time, especially monitoring pressure values ​​and their rate of change.

[0078] In this embodiment, anomaly detection is performed by comparing both the pressure value and the rate of change of the pressure value to determine pressure anomalies. Therefore, when setting safety thresholds, corresponding pressure thresholds and pressure rate thresholds are set. Specifically, when determining whether to enter a Level 1 response, the set Level 1 response pressure threshold and pressure rate threshold are used; when determining whether to enter a Level 2 response, the set Level 2 response pressure threshold and pressure rate threshold are used; and when determining whether to enter a Level 3 response, the set Level 3 response pressure threshold and pressure rate threshold are used.

[0079] The control system 5 (such as the Safety Instrumented System (SIS)) continuously compares the monitoring data with preset safety thresholds (including upper pressure limit, lower pressure limit, and pressure change rate alarm value). When the pressure change rate exceeds the first-level response pressure rate threshold, and / or the pressure value exceeds the first-level response pressure threshold, the "abnormal state recognition" logic is triggered. The system immediately issues an audible and visual warning signal or a remote warning signal to alert the operator and automatically enters the first-level response state.

[0080] 2. Level 1 Response: Flow restriction and process regulation phase.

[0081] During this phase, the system prioritizes attempting to suppress abnormal pressure trends by adjusting operating parameters to avoid direct release.

[0082] After entering Level 1 response, the first step is to determine whether the pressure anomaly in the compressed air energy storage power station system is a sudden pressure surge or a sudden pressure drop:

[0083] (1) If the pressure rise is abnormal, that is, the pressure rise rate is greater than the set pressure rise rate warning deviation value, and the pressure is greater than the normal operating pressure maximum value:

[0084] Control system 5 opens bypass valve 11 via command, guiding some high-pressure gas to the low-pressure circuit or heat dissipation unit. The bypass flow rate used in this system is... The calculation method is as follows:

[0085] ;

[0086] in, The bypass flow coefficient is determined based on the pipe diameter and valve characteristics. For bypass traffic; Indicates system pressure; This indicates the upper limit of the pressure range within which the system operates normally;

[0087] On the other hand, the operating parameters of compressor 1 can also be adjusted synchronously to reduce the speed n to , The calculation method is as follows:

[0088] ;

[0089] in, This is the speed adjustment coefficient; This indicates the adjusted compressor speed; This indicates the current compressor speed; Indicates time;

[0090] Or reduce the guide vane opening and adjust the guide vane opening. to , The calculation method is as follows:

[0091] ;

[0092] in, The guide vane adjustment coefficient limits the inflation rate; This indicates the reduced guide vane opening. This indicates the current guide vane opening.

[0093] (2) If the pressure drop is abnormal, that is, the pressure drop rate is greater than the set pressure drop rate warning deviation value, and the pressure is less than the minimum normal operating pressure:

[0094] On the one hand, the control system 5 can quickly adjust the load of the expansion generator 4. to :

[0095] ;

[0096] in, The load adjustment coefficient for the expansion generator is 4. This indicates the adjusted load of the expansion generator (4 loads). This indicates the current load of the expansion generator (4 loads).

[0097] On the other hand, the opening of the inlet regulating valve can also be reduced. to , The calculation method is as follows:

[0098] ,

[0099] in, The inlet valve adjustment coefficient limits the venting rate; This indicates the adjusted opening degree of the inlet regulating valve of the expansion generator 4; This indicates the current opening degree of the inlet regulating valve of the expansion generator 4; This indicates the lower limit of the pressure range within which the system is operating normally.

[0100] At the same time, the main shut-off valve 7 on the intake pipe of compressor 1 can be pre-closed, such as reducing the opening to 10%-20% to prevent further pressure loss.

[0101] The goal of this stage is to bring the pressure back to the normal range through proactive process control. If, within a set time (e.g., 30s-60s), the rate of pressure change exceeds the secondary response pressure rate threshold, and / or the pressure value exceeds the secondary response pressure threshold, the system determines that the primary regulation is ineffective and automatically enters the secondary response phase.

[0102] 3. Level 2 Response: Controlled Discharge Phase.

[0103] When a Level 1 response fails to contain the pressure anomaly, controlled release measures are initiated.

[0104] Upon entering the secondary response phase, the system prioritizes activating a reclosable control valve (e.g., an electrically or pneumatically controlled vent valve 12) for controlled, continuous venting at a small flow rate. The vented gas can be directed to a silencer, recovery unit, or safe area.

[0105] Based on real-time pressure feedback, the control module dynamically adjusts the opening of the relief valve 12 using a PID (proportional-integral-derivative) control algorithm. By adjusting the opening, the relief rate is precisely controlled, allowing the pressure to drop smoothly and slowly to a safe range, avoiding the shock caused by a sudden pressure drop. During the relief process, the pressure change rate should be less than the set threshold for a stable relief pressure change rate.

[0106] If the pressure is effectively controlled and begins to drop after controlled venting (the rate of pressure change is less than the first-level response pressure rate threshold and the pressure value is less than the first-level response pressure threshold), the system will maintain this state until the pressure returns to normal.

[0107] If the pressure continues to be abnormal, such as the overpressure continuing to worsen, the current pressure rate change value reaches the Level 3 response pressure rate threshold, and / or the pressure value reaches the Level 3 response pressure threshold, then a Level 3 response is triggered.

[0108] 4. Level 3 response: Total shutdown and stepped depressurization phase.

[0109] This stage represents the highest level of protection, designed to prevent catastrophic accidents. The system immediately executes the Emergency Stop (ESD) command, rapidly cutting off the power source to the main compressor 1 / expander generator 4 and closing the main shut-off valve 7 on the main gas line 16, completely isolating the charging and discharging process.

[0110] Simultaneously, a preset tiered discharge sequence is initiated:

[0111] Phase 1:

[0112] Maintain or increase the discharge flow rate of the already opened relief valve 12 in the secondary response. If the current discharge rate is still less than the maximum discharge flow rate of the relief valve 12, the opening degree of the relief valve 12 will be increased to raise the discharge rate to the maximum value of the valve.

[0113] Phase Two:

[0114] If the pressure is still not effectively contained, still exceeds the safety limit of the system design, and the pressure is still rising, the control system 5 will then trigger one or more sets of high-flow safety valves 14 (using pilot-operated or spring-loaded valves) to release a larger flow rate.

[0115] The set pressure of these safety valves 14 needs to be greater than the set secondary response pressure threshold, but must be less than the set pressure of the rupture disc 13 used in the system.

[0116] Release flow Based on the safety valve model 14 and system pressure calculations, the following conditions are met:

[0117] ;

[0118] Where C is the flow coefficient and A is the flow area of ​​the safety valve. Atmospheric pressure This refers to air density.

[0119] Phase Three:

[0120] When the pressure rises to the maximum allowable pressure (usually equal to the pressure at which the system uses the rupture disc 13 to break the pressure), and all the above measures fail, the rupture disc 13 device is triggered to perform a one-time, full-range final release, ensuring that the system pressure never exceeds the absolute safety limit.

[0121] This phased, incremental release method greatly mitigates the impact of a single large-scale release of compressed gas, improves the safety of the entire compressed air energy storage power station, and is applicable to extreme working conditions of varying crisis levels, offering greater flexibility and reducing maintenance costs and time.

[0122] 5. Recovery and Restart Phase.

[0123] Once the system pressure has dropped back to the preset safe operating range through venting or natural equilibrium, and the control system 5 confirms that all parameters are stable (the current pressure value remains stable within this range for a period of time, such as 5-10 minutes, and the pressure change rate is less than the set pressure change rate warning value) and the fault has been eliminated, the system can enter the recovery procedure.

[0124] The recovery process is also under control:

[0125] Close the relief valve 12 in sequence, reset the safety valve 14, slowly open the main shut-off valve 7, and restart the compressor 1 or the expansion generator 4 according to the procedure to avoid secondary damage to the entire system during the recovery process.

[0126] The data for the entire event (pressure, temperature, flow rate, valve status, time, etc.) is then recorded for post-event analysis.

[0127] like Figure 1 As shown, the overall implementation process of this embodiment includes a monitoring phase, a first-level response phase, a second-level response phase, a third-level response phase, and a termination phase.

[0128] During the monitoring phase, the pressure values ​​of the system detected by the sensors are transmitted back to the control module;

[0129] The control module, based on the first-level response criteria, determines whether to enter the first-level response stage according to the current system pressure. If so, it issues an audible and visual alarm and simultaneously enters the first-level response. Specifically, it opens the bypass valve 11 on the relief bypass 17, adjusts the compressor 1 speed, and after the above response is executed, it determines whether the system pressure has returned to normal.

[0130] If the pressure still does not return to normal and continues to rise, a secondary response is triggered, opening the relief valve 12 to release the flow, and then it is determined again whether the pressure has returned to normal after the secondary response is executed;

[0131] If the pressure still does not return to normal and continues to rise, the first stage of the three-level response is triggered, opening the relief valve 12 to its maximum, and then determining whether the system pressure has returned to normal. If it still does not return to normal and continues to rise, the second stage of the three-level response is triggered, at which point the safety valve 14 is opened, and then determining whether the system pressure has returned to normal. If it still does not return to normal and continues to rise, the third stage of the three-level response is triggered, at which point the rupture disc 13 is controlled to rupture, allowing for full release.

[0132] If, during the execution of the Level 1, Level 2, and Level 3 responses, it is determined that the pressure has returned to normal, then the next step of the process will not be continued, and the process will enter the termination phase.

[0133] The multi-level protection and controlled discharge method provided in this embodiment mainly relies on the following modules:

[0134] 1. Detection module:

[0135] Composed of distributed pressure sensors, temperature sensors, flow meters, and other instruments, it is responsible for real-time monitoring of the status parameters of the gas storage device, main pipeline, and key equipment. The pressure sensor has an accuracy of no less than 0.5 class and a sampling frequency of no less than 10 Hz; the temperature sensor has a measurement range of -40℃ to 200℃ and an accuracy of no less than ±1℃; the flow meter adopts differential pressure or vortex flow, with a measurement error of no more than ±2%.

[0136] 2. Control Module:

[0137] For the core processing unit, high-reliability programmable logic controllers (PLCs) or distributed control systems (DCS) should be preferred, especially safety instrumented systems (SIS) with Safety Integrity Level (SIL) certification (not lower than SIL-2).

[0138] This module stores and executes the aforementioned multi-level response logic, and is responsible for data judgment, threshold comparison, and issuing control commands to the actuator. The command response time does not exceed 100ms.

[0139] 3. Implementing agency:

[0140] This includes a series of valves and their actuation devices, which are the direct implementers of protective actions:

[0141] Main shut-off valve 7: Located in the main gas line 16, used for emergency isolation, with a closing time not exceeding 1 second and a leakage level not lower than ANSI Class V (valve leakage level five).

[0142] Bypass valve 11: Used for flow adjustment and small flow release in the first-level response, adopting the on / off type or proportional type, and the response time does not exceed the specified time.

[0143] Relief valve 12: Used for flow relief in the second-level response and the first stage of the third-level response. It is of on / off type or proportional type, and the response time does not exceed the specified time.

[0144] Safety valve 14 assembly: includes multi-stage safety valves 14 with different set pressures, providing non-frequent large flow discharge, with a set pressure deviation of no more than ±3% and a reseating pressure of no less than 80% of the set pressure.

[0145] Rupture disc 13 (rupture plate): As the ultimate physical protection barrier that can no longer be closed, the rupture pressure deviation does not exceed ±5%, and the rupture temperature adapts to the possible temperature range of the system.

[0146] 4. Communication and Alarm Module:

[0147] It is responsible for communicating system status, alarm information, and operation commands with the power plant's main control room and remote monitoring center, using industrial Ethernet or a dedicated communication link. It can achieve real-time alarms (audible and visual alarms, monitoring interface pop-up alarms), event logging (storage capacity of at least one year of event data), historical data storage (sampling interval is configurable, such as 1 second by default), and remote interlocking control functions.

[0148] The system adopts a modular design, which can flexibly configure the number and accuracy of sensors, the diameter and capacity of actuators (valves) and the threshold of control logic according to the specific CAES power plant's energy storage scale (e.g., 10MW-1000MW, MW is megawatt), gas storage volume (e.g., 1000m³-100000m³, m³ is cubic meter), working pressure range (e.g., 10MPa-100MPa, MPa is megapascal).

[0149] The method of this embodiment is applied to a CAES power plant that uses underground salt cavern gas storage. The power plant has an energy storage capacity of 100MW, a gas storage salt cavern volume of 50,000m³, a normal operating pressure range of 20MPa-30MPa, and a maximum allowable operating pressure (MAWP) of 35MPa.

[0150] The sensors of the detection module (PT: pressure transmitter, accuracy class 0.2, sampling frequency 10Hz; TT: temperature transducer, measurement range -40℃-200℃, accuracy ±0.5℃; FT: flow transmitter, vortex type, measurement error ±1.5%) are arranged on the inlet and outlet main pipes of the gas storage cave 2 (one PT, one TT, and one FT are arranged on each), as well as near the outlet of compressor 1 (one PT and one TT) and the inlet of expander generator 4 (one PT and one TT).

[0151] The above refers to PT as a pressure transmitter, used to monitor system pressure; TT as a temperature sensor, used to monitor system temperature; and FT as a flow transmitter, used to monitor system flow.

[0152] The control module adopts SIL-2 level SIS, receives signals from all sensors, and has the following preset thresholds: warning threshold is 0.5MPa / s (MPa / s means megapascals per second), pressure warning deviation is 2MPa / s, the maximum value of the first-level response action threshold is 32MPa, the minimum value is 18MPa / s, the threshold for stable release pressure change rate is 0.1MPa / s, the set pressure of safety valve 14 is 33MPa, and the set pressure of rupture disc 13 is 35MPa.

[0153] When the system detects that the pressure in gas storage cavern 2 rises from 28MPa to 31MPa within 10 seconds, with a pressure change rate of 0.5MPa / s, but the deviation of the pressure from the normal upper limit (30MPa) is 1MPa, which is less than the pressure change warning value, no warning is triggered at this time; however, if the pressure continues to rise and reaches 32MPa within 5 seconds, the pressure change rate is still less than the set pressure change rate warning value, but the pressure change has exceeded or equaled the pressure change warning value, triggering the abnormal detection and warning stage, the system issues an audible and visual alarm, and enters the first-level response preparation state.

[0154] During the first-level response phase, due to a sudden increase in pressure exceeding the pressure warning value, the control module first instructs the opening of the bypass valve 11 connected to the low-pressure buffer tank 3 (pressure 5MPa), calculates the bypass flow rate according to the formula, and adjusts the opening of the bypass valve 11 to the corresponding flow rate; at the same time, the speed of compressor 1 is adjusted, the target speed is calculated, and the speed of compressor 1 is gradually reduced to the final adjustment value.

[0155] If 1 minute (more than the set time) The pressure still rose to 33 MPa, triggering a secondary response and opening relief valve 12 (electric regulating valve). PID control was used to adjust the valve opening to maintain the pressure at... The pressure gradually decreased at a rate of -0.1 MPa / s to the target pressure of 30 MPa.

[0156] If the pressure continues to rise to 34 MPa (close to the set pressure of 33 MPa for safety valve 14, with slight overpressure due to system delays and other factors), the first stage of the three-level response is triggered, adjusting the opening of the relief valve 12 to the maximum and increasing the relief flow rate to the highest level. If the pressure still rises to 34.5 MPa, the second stage of the three-level response is triggered, opening safety valve 14 (set pressure 33 MPa). If the pressure eventually rises to 35 MPa, the third stage of the three-level response is triggered, rupture disc 13 ruptures (set pressure 35 MPa), and full relief is performed to ensure that the pressure does not exceed 35 MPa.

[0157] Throughout the process, alarm information (pressure value, pressure change rate, valve status, response stage, etc.) is uploaded to the central control room in real time, displayed and stored on the monitoring interface.

[0158] When the system is restored, wait for the pressure to drop to the 28MPa-30MPa range and stabilize for 5 minutes. After confirming that the fault has been eliminated (such as the speed control system fault of compressor 1 has been repaired), close the rupture disc 13 in sequence (a new disc needs to be replaced), reset the safety valve 14, close the relief valve 12, close the bypass valve 11, and slowly open the main shut-off valve 7 (the opening degree is increased from 0 to 100% at a rate of 0.5% / s). Gradually increase the speed of compressor 1 to the normal speed according to the procedure to restore normal operation.

[0159] Example 2

[0160] This embodiment discloses a multi-level protection and controlled discharge control system for a compressed air energy storage power station.

[0161] A multi-level protection and controlled discharge control system for compressed air energy storage power stations, including:

[0162] The system setup module is configured to: build a compressed air energy storage power station system including a discharge bypass and a discharge valve and a safety valve located downstream of the discharge bypass;

[0163] The pressure anomaly detection module is configured to monitor the pressure value of the compressed air energy storage power station system and determine whether a pressure anomaly has occurred.

[0164] The tiered response module is configured to implement a tiered response mechanism when an abnormal pressure occurs.

[0165] Enter Level 1 response, adjust the operating parameters of the compressed air energy storage power station system, or activate the discharge bypass to suppress abnormal pressure trends;

[0166] When the first-level response fails to suppress the pressure abnormality, the second-level response is initiated, and the opening of the relief valve is adjusted to release the gas.

[0167] When the Level 2 response fails to suppress the pressure anomaly, it enters the Level 3 response, adopting a stepped release sequence. While increasing the opening of the release valve, the opening of the safety valve is gradually increased to release the gas. When the release valve and the safety valve fail to suppress the pressure anomaly, the final release is carried out in one go by triggering the rupture disc.

[0168] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0169] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A multi-level protection and controlled discharge control method for compressed air energy storage power stations, characterized in that, Includes the following steps: Construct a compressed air energy storage power station system that includes a discharge bypass and a discharge valve and safety valve located downstream of the discharge bypass; Monitor the pressure value of the compressed air energy storage power station system to determine if any pressure abnormalities occur; When abnormal pressure occurs, a tiered response mechanism is adopted: Enter Level 1 response, adjust the operating parameters of the compressed air energy storage power station system, or activate the discharge bypass to suppress abnormal pressure trends; When the first-level response fails to suppress the pressure abnormality, the second-level response is initiated, and the opening of the relief valve is adjusted to release the gas. When the secondary response fails to suppress the pressure abnormality, the tertiary response is initiated, employing a stepped release sequence. While increasing the opening of the release valve, the opening of the safety valve is gradually increased to release the gas. When the release valve and safety valve fail to suppress the pressure abnormality, the final release is achieved by triggering the rupture disc for a one-time, full-range final release. The construction process of the compressed air energy storage power station system is as follows: Construct the main gas pipeline between the compressor, gas storage cavern, and expander generator; A venting bypass is installed on the main gas pipeline between the gas storage cavern and the expansion generator. A low-pressure buffer tank is connected to the end of the venting bypass, and a bypass valve is installed on the venting bypass. A vent valve, safety valve, and rupture disc are installed on the main gas pipeline downstream of the vent bypass. A main shut-off valve is installed on the compressor's intake pipe; After entering Level 1 response, the first step is to determine whether the pressure anomaly in the compressed air energy storage power station system is a sudden pressure rise or a sudden pressure drop. When the pressure anomaly is a sudden pressure rise: On the one hand, control the opening of the bypass valve or the relief valve to guide some of the high-pressure gas to the low-pressure circuit or the heat dissipation unit; On the other hand, the compressor operating parameters can be adjusted synchronously to reduce the compressor speed or reduce the guide vane opening. The flow rate of the bypass valve is calculated as follows: ； in, For bypass traffic; The bypass flow coefficient; Indicates system pressure; This indicates the upper limit of the pressure range within which the system operates normally; The specific adjustment method for compressor operating parameters is as follows: ； in, This indicates the adjusted compressor speed; This indicates the current compressor speed; This is the speed adjustment coefficient; Indicates time; The specific method for reducing the guide vane opening is as follows: ； in, This indicates the reduced guide vane opening. Indicates the current guide vane opening; This refers to the guide vane adjustment coefficient; When the pressure anomaly is a sudden pressure drop: On the one hand, adjust the load on the expansion generator; On the other hand, reduce the opening of the inlet regulating valve of the expansion generator, or control the main shut-off valve to partially close it; The specific method for adjusting the load of the expander generator is as follows: ； in, This indicates the adjusted load on the expansion generator; This indicates the current load on the expansion generator; This refers to the load adjustment coefficient for the expansion generator; The opening degree of the inlet regulating valve of the expander generator, specifically the method of closing it is as follows: ， in, This indicates the adjusted opening degree of the expansion generator inlet regulating valve; This indicates the current opening degree of the expansion generator inlet regulating valve; This refers to the adjustment coefficient of the inlet valve; Indicates system pressure; This indicates the lower limit of the pressure within the normal operating pressure range of the system.

2. The multi-level protection and controlled discharge control method for compressed air energy storage power stations as described in claim 1, characterized in that, Monitoring the pressure values ​​of the compressed air energy storage power station system to determine if any pressure anomalies occur, specifically including: Pressure sensors are installed in the compressed air energy storage power station system. The pressure sensors are installed at key pipeline nodes and the inlet and outlet of the gas storage cavity. Obtain the pressure value returned by the pressure sensor; The pressure value is compared with a preset safety threshold. When the rate of pressure change exceeds the first-level response pressure rate threshold and / or the pressure value exceeds the first-level response pressure threshold, a pressure anomaly is determined, and a first-level response is initiated.

3. The multi-level protection and controlled discharge control method for compressed air energy storage power stations as described in claim 1, characterized in that, When the rate of pressure change exceeds the second-order response pressure rate threshold, and / or the pressure value exceeds the second-order response pressure threshold, the system enters the second-order response phase; after entering the second-order response: The opening degree of the relief valve is dynamically adjusted by using a PID control algorithm to continuously and controllably release gas. The rate of pressure change during controlled venting is kept below a pre-set threshold for the rate of pressure change during stable venting. If the pressure is effectively controlled and begins to drop after controlled venting, maintain the current state until the pressure returns to normal. If the pressure continues to be abnormal after controlled venting, a Level 3 response is triggered when the rate of pressure change exceeds the Level 3 response pressure rate threshold and / or the pressure value exceeds the Level 3 response pressure threshold.

4. The multi-level protection and controlled discharge control method for compressed air energy storage power stations as described in claim 1, characterized in that, Before entering a Level 3 response and adopting a stepped release sequence, an emergency shutdown command is first executed to quickly cut off the power source of the compressor and expander generator, and close the main shut-off valve on the main gas pipeline.

5. The multi-level protection and controlled discharge control method for compressed air energy storage power stations as described in claim 1, characterized in that, In a Level 3 response, a tiered release sequence is employed, specifically including: Phase 1: Maintain or increase the opening of the relief valve that has been opened in the secondary response, and increase the relief rate to the maximum value of the relief valve; Second stage: If the pressure is still not effectively contained, the safety valve will be triggered to release the gas; The third stage: When the pressure rises to the maximum allowable pressure and the measures in the first and second stages fail, the rupture disc is triggered to perform a one-time, full-range final release.

6. The multi-level protection and controlled discharge control method for compressed air energy storage power stations as described in claim 5, characterized in that, The safety valve's set pressure is greater than the preset secondary response pressure threshold, but less than the rupture disc's set pressure.

7. A multi-level protection and controlled discharge control system for a compressed air energy storage power station, characterized in that, include: The system setup module is configured to: build a compressed air energy storage power station system including a discharge bypass and a discharge valve and a safety valve located downstream of the discharge bypass; The pressure anomaly detection module is configured to monitor the pressure value of the compressed air energy storage power station system and determine whether a pressure anomaly has occurred. The tiered response module is configured to implement a tiered response mechanism when an abnormal pressure occurs. Enter Level 1 response, adjust the operating parameters of the compressed air energy storage power station system, or activate the discharge bypass to suppress abnormal pressure trends; When the first-level response fails to suppress the pressure abnormality, the second-level response is initiated, and the opening of the relief valve is adjusted to release the gas. When the Level 2 response fails to suppress the pressure anomaly, it enters the Level 3 response, adopting a stepped release sequence. While increasing the opening of the release valve, the opening of the safety valve is gradually increased to release the gas. When the release valve and the safety valve fail to suppress the pressure anomaly, the final release is carried out in one go by triggering the rupture disc.

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