Emergency trip system of steam turbine

Abstract

The emergency trip system of the steam turbine comprises AST electromagnetic valves and intermediate relays, the number of the intermediate relays is N times that of the AST electromagnetic valves, and N is an integer not smaller than 2; the AST electromagnetic valves control the EH oil way according to a double-channel and series-parallel connection structure arrangement mode, and every N intermediate relays are connected in parallel and then are connected in series in power supply loops of the corresponding AST electromagnetic valves respectively. A plurality of intermediate relays are connected in parallel to control a loop to control an electrical control instruction and a power load of the AST electromagnetic valve, normally open contacts of the relays are connected in parallel to the loop, when one intermediate relay fails, other intermediate relays can still maintain power supply, and risks are greatly reduced; meanwhile, the multiple relays can disperse current loads and reduce the ablation risk, by means of the design, the situation that a coil of the AST electromagnetic valve is mistakenly powered off and opened due to faults of the intermediate relay or failure of a contact can be eradicated, the reliability and safety of loop control are effectively improved, and intrinsic safety is achieved.

Description

Technical Field

[0001] The embodiments of this specification relate to the technical field of steam turbine control and protection, and particularly to a steam turbine emergency trip system. Background Art

[0002] In the ETS (Emergency Trip System) of a steam turbine in a thermal power plant, the AST (Automatic Shutdown Trip) solenoid valve is the core component for executing on-site instructions. It ensures the safety of the unit through multi-dimensional functions: during the startup phase, it is energized to close the EH oil drain channel, establish the AST oil pressure to enable the steam turbine to be put on hold, and provide the EH oil pressure for each main steam valve, high-pressure control valve, and intermediate main valve, laying the startup conditions; during normal operation, it remains energized to maintain the emergency trip oil pressure, ensuring the opening of the steam valves, and at the same time providing hydraulic power for the high- and medium-pressure control valves to achieve speed regulation and load stability; in case of critical conditions such as overspeed and low lubricating oil pressure, the solenoid valve de-energizes to trigger the opening of the drain channel, and the rapid release of the AST oil causes the emergency trip oil pressure to drop suddenly, driving the unloading valve of the steam valve oil motor to forcibly close all steam valves and cut off the steam supply to achieve emergency shutdown; in terms of structural design, a dual-channel independent architecture is adopted, and at least one solenoid valve in each channel needs to act to relieve the AST oil pressure. The redundancy mechanism is used to avoid the protection failure caused by a single-channel fault. The above functions work together to not only ensure the stability of the oil pressure in the steam turbine regulation system but also quickly and reliably trigger safety protection in case of an emergency, effectively preventing serious accidents.

[0003] Currently, the on-site final execution elements of the steam turbine ETS generally use 4 AST shutdown solenoid valves, which are arranged in a dual-channel, series-parallel structure to control the EH oil circuit. However, in this deployment method, there is a risk of single-point failure in the AST solenoid valve control circuit. If a coil failure or contact burnout occurs, it will cause the solenoid valve coil to de-energize, and then the solenoid valve will malfunction and open, releasing the EH oil pressure, which may trigger an unexpected shutdown without a trip instruction, affecting the safety of the unit.

[0004] Therefore, how to avoid the misoperation and refusal of the protection system and ensure the intrinsic safety of the AST electrical circuit control is an urgent problem for those skilled in the art. Summary of the Invention

[0005] In view of this, the embodiments of this specification provide a steam turbine emergency trip system to solve the technical defects existing in the prior art.

[0006] A steam turbine emergency trip system includes: an AST solenoid valve and an intermediate relay, the number of the intermediate relays is N times the number of the AST solenoid valves, and N is an integer not less than 2; The AST solenoid valve controls the EH oil circuit in a dual-channel, series-parallel structure. After each N intermediate relays are connected in parallel, they are connected in series in the power supply circuit of each corresponding AST solenoid valve.

[0007] In one embodiment, the steam turbine emergency tripping system further comprises: a current transmitter and a voltage transmitter are respectively provided for the AST solenoid valve coil of each of the AST solenoid valves; The current transmitter is used to collect the working current of the AST solenoid valve coil, and the current transmitter is used to collect the working voltage of the AST solenoid valve coil.

[0008] In one embodiment, the turbine emergency shutdown system further includes: a temperature collecting block and a micro thermal resistor are respectively installed on the shutdown block of the turbine emergency shutdown system, the oil inlet pipe and the oil return pipe of the turbine high-pressure fire-resistant oil system to measure the oil inlet temperature and the oil return temperature.

[0009] In one embodiment, the steam turbine emergency shutdown system further includes: an internal leakage identification module connected to the temperature collecting block and the micro thermal resistor, for collecting the oil inlet temperature and the oil return temperature, and performing internal leakage judgment on the shutdown block according to the deviation between the oil inlet temperature and the oil return temperature, and generating an internal leakage identification result.

[0010] In one embodiment, the steam turbine emergency shutdown system further comprises: a DCS analysis system for collecting working status information of each component in the steam turbine emergency shutdown system, and performing status monitoring and alarming according to the working status information; The working status information includes: the power supply status of the AST solenoid valve, the working status, working current, working voltage of the AST solenoid valve coil, and one or more of the internal leakage identification results.

[0011] In one embodiment, the steam turbine emergency shutdown system further includes: a heat dissipation device installed for the AST solenoid valve coil of each of the AST solenoid valves.

[0012] In one embodiment, the heat dissipation device is installed on the working heating surface of the AST solenoid valve coil.

[0013] In one embodiment, a thin-film patch temperature measuring element is embedded in the mounting interface between the heat dissipation device and the AST solenoid valve coil to monitor the coil temperature.

[0014] In one embodiment, a fan is installed on the top of the heat dissipation device to increase the heat dissipation speed.

[0015] In one embodiment, the power supply voltage of the fan is selected to be 12 volts DC and 0.5 amperes.

[0016] The steam turbine emergency shutdown system provided in this manual controls the electrical control instructions and power load of the AST solenoid valve through a parallel control circuit of multiple intermediate relays. The normally open contacts of multiple relays are connected in parallel to the circuit. When one branch fails, the other branches can still maintain power supply. Only a complete failure will cause power failure, which greatly reduces the risk. At the same time, multiple relays can also disperse the current load and reduce the risk of ablation. When one contact fails, the other branches can still be disconnected independently to achieve fault isolation. This design increases the failure probability from "single event failure" to "multiple event failure" through physical, functional, and logical redundancy, fundamentally solving the single-circuit reliability bottleneck, and can prevent the AST solenoid valve coil from accidentally losing power and opening due to the failure of the intermediate relay or the contact, effectively improving the reliability and safety of the circuit control and achieving inherent safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the series and parallel structure of the EH oil circuit of an AST solenoid valve provided by an embodiment of this specification; Figure 2 This is a detailed diagram of an intermediate relay control provided by an embodiment of this specification; Figure 3 It is a structural schematic diagram of a steam turbine emergency tripping system provided by an embodiment of this specification; Figure 4 This is a schematic diagram of an intermediate relay installation of channel 1 provided in one embodiment of this specification; Figure 5 This is a circuit diagram for installing a current transmitter and a voltage transmitter provided by an embodiment of this specification; Figure 6 This is a schematic diagram of the actual installation effect of a current transmitter provided by an embodiment of this specification; Figure 7 This is a schematic diagram of the actual installation effect of a voltage transmitter provided by an embodiment of this specification; Figure 8 This is a schematic diagram of a display and monitoring page for implementing parameters in a DCS system provided by an embodiment of this specification; Figure 9 It is a product schematic diagram of a heat dissipation device provided by an embodiment of this specification; Figure 10 This is a schematic diagram of the installation of a thin-film patch temperature measuring element provided in one embodiment of this specification. DETAILED DESCRIPTION

[0018] Numerous specific details are set forth in the following description to facilitate a full understanding of this specification. However, this specification can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the connotation of this specification. Therefore, this specification is not limited by the specific implementations disclosed below.

[0019] The terms used in one or more embodiments of this specification are for the purpose of describing specific embodiments only and are not intended to limit one or more embodiments of this specification. The singular forms "a" and "the" used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" used in one or more embodiments of this specification refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0020] It should be understood that although the terms first, second, etc. may be used in one or more embodiments of this specification to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of one or more embodiments of this specification, the first may also be referred to as the second, and similarly, the second may also be referred to as the first. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0021] Currently, the on-site final actuators of the steam turbine ETS (Emergency Trip System) generally adopt 4 AST shut-off solenoid valves (20-1 / AST, 20-3 / AST, 20-2 / AST, 20-4 / AST). These 4 AST solenoid valves are arranged in a dual-channel, series-parallel structure to control the EH oil circuit, as Figure 1 shown in the schematic diagram of the series and parallel structures of the AST solenoid valve EH oil circuit. 20-1 / AST and 20-3 / AST are in parallel to form Channel 1, 20-2 / AST and 20-4 / AST are in parallel to form Channel 2, and Channel 1 and Channel 2 are in series.

[0022] The main working mechanism is as follows: During normal operation, the coils of the 4 AST solenoid valves are simultaneously energized and magnetized to close, thus blocking the oil drain channel of the fire-resistant oil on the emergency trip (AST) main pipe, enabling the oil pressure in the lower chambers of all steam valve actuators to be established, ensuring the normal operation and regulation of the unit. As long as any one solenoid valve coil in Channel 1 and any one solenoid valve coil in Channel 2 lose power, the unit will trip and shut down. However, when the 2 solenoid valve coils in the same channel lose power and drain the fire-resistant oil, as long as the 2 solenoid valve coils in the other channel are still energized and magnetized, the unit will not trip and the unit can still continue to operate.

[0023] However, the applicant has found that in the current electrical control circuits of AST solenoid valves, only one intermediate relay corresponding to one AST solenoid valve coil is used to send out the electrical command action signal. The power supply to each AST solenoid valve coil is controlled by the contacts of only one intermediate relay and sent to the coil. As Figure 2 shown in the detailed diagram of the intermediate relay control for 20-1 / AST and 20-3 / AST in Channel 1, where the solenoid valve coil 1JD13 of 20-1 / AST uses the contact NO16 of the JD11 intermediate relay as the electrical command action signal. Then, when there is no trip command generated and the turning-on command is issued, the JD11 ( Figure 2 taking one coil as an example in the figure) intermediate relay operates, and the normally open contact NO16 operates and closes. The contact is connected and the power supply is sent to the 20-1 / AST solenoid valve coil and remains in the energized state for a long time. If the JD11 intermediate relay fails or the NO16 contact is burned out due to long-term operation, the 20-1 / AST solenoid valve coil will lose power, and the 20-1 / AST solenoid valve will open without any command and drain the EH oil pressure of this circuit, thus affecting the safety of the unit.

[0024] In view of this, the present application proposes a structure of a steam turbine emergency trip system to prevent misoperation and refusal of operation of the protection system, and can ensure the inherent safety of the AST electrical circuit control.

[0025] Embodiment 1: Refer to Figure 3 , Figure 3 which shows a schematic structural diagram of a steam turbine emergency trip system provided according to an embodiment of this specification, mainly including the following components: AST solenoid valves and intermediate relays.

[0026] Among them, the number of intermediate relays is N times the number of AST solenoid valves, and N is an integer not less than 2. The number of intermediate relays is more than twice the number of AST solenoid valves, at least twice, to ensure that each AST solenoid valve has at least two intermediate relays to jointly implement the control of electrical commands.

[0027] Among them, the AST solenoid valves control the EH oil circuit in the way of dual-channel, series-parallel structure arrangement. Refer to Figure 1 the shown structure. Taking 4 AST solenoid valves as an example, after every N intermediate relays are connected in parallel, they are respectively connected in series in the power supply circuits of the corresponding AST solenoid valves. The parallel intermediate relays jointly provide electrical commands for the directly connected AST solenoid valves.

[0028] Taking N as 2, Figure 4 shown in the installation schematic diagram of the intermediate relay in Channel 1, the electrical control commands and power loads of the AST solenoid valves are controlled through the dual-branch intermediate relay control circuit, and Figure 2Compared with the shown structure, an additional intermediate relay is added in parallel at each intermediate relay (still taking one coil as an example). The double-branch intermediate relay control circuit is used to control the electrical control instruction and power load of the AST solenoid valve. The normally open contacts of the double relays are connected in parallel to the circuit. When one branch fails, the other branch can still maintain power supply, and only a double fault will cause power loss, greatly reducing the risk. At the same time, the double relays can also disperse the current load. The current flowing through a single contact is reduced by about 50%, reducing the risk of ablation. And when one contact fails, the other branch can be independently disconnected to achieve fault isolation. Through physical, functional, and logical redundancy, this design improves the failure probability from "single-event failure" to "double-event failure", fundamentally solving the reliability bottleneck of the single loop, and can prevent the AST solenoid valve coil from losing power and opening erroneously due to the failure of the intermediate relay or the failure of the contact, effectively improving the reliability and safety of the loop control and achieving intrinsic safety.

[0029] In this embodiment, only N = 2 is taken as an example to introduce the structure and implementation function of the intermediate relay. When N takes other integers, its working principle can be referred to the above introduction. N intermediate relays are connected in parallel and then connected in series to the power supply circuit of the AST solenoid valve. The specific value of N can be set accordingly according to parameters such as the accuracy requirement and usage cost in the actual application scenario, which will not be elaborated here.

[0030] It should be noted that to highlight the key points, only the structure of the AST solenoid valve and the intermediate relay part in the turbine emergency trip system provided in this embodiment is introduced. For other devices in the turbine emergency trip system, such as sensors and detection elements (speed sensors, axial displacement sensors, etc.) for real-time monitoring of the unit operation parameters, controllers and logic operation units (relay logic cabinets, programmable logic controllers PLC), actuators and hydraulic components (diaphragm valves, oil motors, EH oil systems), and alarm and signal indication devices (audible and visual alarms), etc., their structures and connection states are not limited and can be set accordingly according to the needs of different application scenarios with reference to relevant technologies, which will not be elaborated here.

[0031] Embodiment 2: When the unit is operating normally, the method of connecting four AST solenoid valves in series and parallel on site has high reliability, but this method only considers the reliability of the mechanical oil circuit, but does not consider the reliability and life of the solenoid valve coil in the electrical aspect. The solenoid valve coil is electrically excited for a long time, up to half a year or even more than a year. The unit is not stopped, and the solenoid valve coil will continue to work under load. The coil is excited by 220V AC voltage. Although the AC voltage is reduced to 110V, the heat generated by the coil is still very large. The infrared temperature measurement at the center of the wire core is as high as 100℃. If DC voltage is used for excitation, the heat generated will be even greater. In this way, it is impossible to predict when the coil will burn out and take preventive measures, which can easily cause the unit to trip incorrectly.

[0032] The existing AST solenoid valve electrical control circuit only simply sends the electrical command action signal to the solenoid valve coil, but does not consider how to prevent coil damage, how to quantitatively monitor the status of the four coils, how to most intuitively see the working parameters of the coils, and how to issue early warnings on the status of the coils to avoid unit tripping and non-stopping due to coil burning as much as possible.

[0033] This embodiment provides an electrical control circuit, which uses a specific device to collect electrical parameters to achieve comprehensive online monitoring of the working status of the AST solenoid valve. Specifically, a current transmitter and a voltage transmitter are added to the control circuit, such as Figure 5 The following is the installation circuit diagram of the current transmitter and voltage transmitter of the 20-1 / AST solenoid valve and 20-3 / AST solenoid valve. Figure 6 The figure shows the actual installation effect of the current transmitter. Figure 7 The figure shows the actual installation effect of the voltage transmitter. Among them, the current transmitter is used to collect the working current of the AST solenoid valve coil, and the voltage transmitter is used to collect the working voltage of the AST solenoid valve coil. The collected working current and working voltage can be used for status monitoring and fault diagnosis of the AST solenoid valve coil. Specifically, it can be analyzed manually, or the collected working current and working voltage can be sent to the DCS system for automatic monitoring. At the same time, the current and voltage over-limit alarms can be added to the logic, thereby realizing automatic alarms, which are not limited here.

[0034] Embodiment three: At present, the heat generated by high-pressure oil flowing through the throttling element cannot be monitored, which can easily cause the oil temperature to exceed the oil tolerance limit, resulting in oil degradation, seal corrosion and valve core sticking, directly affecting the reliability of actuators such as AST solenoid valves, and even causing the emergency shut-off function to fail. In addition, when the AST solenoid valve leaks internally or the oil motor wears, the pressure parameters may not change significantly. When the oil circuit is blocked, pressure monitoring alone cannot quickly locate it, and delays in troubleshooting may damage upstream components.

[0035] In order to capture the changes in oil temperature and temperature difference in real time, give early warnings of potential hazards such as abnormal heating and leakage, improve the reliability of the system, and reduce maintenance costs, in this embodiment, temperature collection blocks and miniature thermal resistors are installed on the shutdown block of the turbine emergency shutdown system, the inlet pipe and the return pipe of the turbine high-pressure fire-resistant oil system (turbine EH oil system) respectively, for measuring the inlet oil temperature and the return oil temperature. By accurately monitoring the temperature of the hydraulic circuit, the safe and reliable operation of the system is ensured.

[0036] The shutdown block is a component in the turbine emergency shutdown system. The shutdown block is closely connected to the inlet and return pipes. When the oil flows through the shutdown block, its temperature is closer to the oil temperature in the inlet and return pipes. Installing the temperature collection block can better collect and conduct the heat of the oil, making the temperature measured by the miniature thermal resistor more accurately represent the actual temperature of the oil, and reducing the measurement error caused by factors such as environmental heat dissipation.

[0037] As a temperature conduction medium, the temperature collection block reduces the influence of oil flow disturbance on the temperature measurement accuracy by increasing the contact area with the oil circuit, ensuring the accuracy of the data collected by the miniature thermal resistor. The miniature thermal resistor has the characteristics of small volume and low thermal inertia. Combined with the fast heat conduction design of the temperature collection block, it can capture the dynamic changes of the oil temperature in real time and meet the requirements of the ETS system for monitoring transient parameters.

[0038] By arranging temperature measurement points on the inlet pipe (high-pressure oil side) and the return pipe (low-pressure oil side) respectively, it is possible to monitor whether the oil temperature rises abnormally, avoiding oil deterioration, seal failure or thermal deformation of hydraulic components caused by high temperature; an internal leakage identification module connected to the temperature collection block and the miniature thermal resistor can be further set to compare the inlet and return oil temperature differences, and whether there is internal leakage can be judged through the temperature deviation.

[0039] During internal leakage, the additional oil flow directly returns through the leakage channel, intensifying throttling and frictional heating, resulting in a significant increase in the return oil temperature. The greater the leakage amount, the more obvious the abnormal temperature rise. This internal leakage detection method can achieve non-invasive online monitoring without disassembling the system. It can give early warnings in advance through abnormal temperature differences at the initial stage of leakage (such as slight wear of the sealing surface), detect potential hazards earlier than traditional pressure monitoring, and has low cost and convenient implementation; in addition, by further combining flow parameters, the heat loss of the circuit can be calculated, and the energy efficiency of the system and the working state of components can also be evaluated.

[0040] Embodiment 4: To comprehensively monitor the working status of the steam turbine emergency trip system, a DCS analysis system can be further set up in the steam turbine emergency trip system. The DCS analysis system is connected to the status monitoring components of each component in the steam turbine emergency trip system, and is used to collect the working status information of each component in the steam turbine emergency trip system, and perform status monitoring and alarm according to the working status information. Among them, the working status information can include: the power supply status of the AST solenoid valve, the working status of the AST solenoid valve coil, the working current of the AST solenoid valve coil, the working voltage of the AST solenoid valve coil, and one or more of the internal leakage identification results As Figure 8 Shown is a schematic diagram of the display and monitoring page for implementing parameters in the DCS system. It comprehensively monitors, alarms, and judges faults for the power supply status of the AST solenoid valve, the working status of the AST solenoid valve coil, the working current and voltage of the coil, and whether there is internal leakage in the shut-off block. Real-time monitoring of multiple parameters such as pressure and temperature can capture early anomalies, avoid the expansion of faults, shift from regular maintenance to condition-based maintenance, reduce maintenance costs, and improve the stability of the power grid

[0041] Example Five: Too high or too low power supply voltage, design defects or aging of the coil, control circuit faults (such as contact adhesion), etc. will cause abnormal current or continuous power-on, resulting in heat generation. At the same time, spool jamming, excessive load or improper installation (such as loose fitting, wiring pressing the wire) will increase the suction resistance or friction, and will also cause the power consumption to rise, further leading to coil heating. And overheating of the solenoid valve coil poses multiple threats to equipment safety and system operation. In view of this, in this embodiment, a heat dissipation device is proposed for the solenoid valve coil, and a method for measuring the temperature of the solenoid valve coil is proposed

[0042] Install heat dissipation devices for each AST solenoid valve coil, such as heat sinks, fan heat dissipation systems, etc. As Figure 9 Shown is a product schematic diagram of a heat dissipation device, which always controls the temperature of the coil below the upper limit that threatens system operation, and reduces the threat to system operation caused by abnormal operation of various voltages and currents through active heat dissipation

[0043] For the specific installation location, no limitation is made in this embodiment. To ensure the heat dissipation effect, the heat dissipation device can be installed on the working heating surface of the AST solenoid valve coil. This structure helps the coil to dissipate heat quickly and greatly reduces the probability of thermal damage

[0044] Furthermore, a thin-film patch temperature measuring element can be embedded in the installation joint surface between the heat dissipation device and the AST solenoid valve coil to monitor the coil temperature. As Figure 10The figure shows an installation schematic diagram of a film type patch temperature measuring element. The working heating surface of the coil is combined with a special copper radiator as a whole. At the joint surface, a film type patch temperature measuring element is embedded by a special process to measure the coil temperature and transmit it remotely to the control room for monitoring. Optionally, a fan can be installed on the top of the radiator to improve the heat dissipation speed and efficiency. The fan voltage can be selected as DC12V, 0.5A to ensure the safety and stability of operation. This structure helps the coil to dissipate heat quickly, greatly reduces the probability of thermal damage, extends the service life, and at the same time, the internal temperature measuring element can also monitor the working temperature of the coil in real time, which is beneficial to grasping the health status of the coil.

[0045] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the embodiments of this specification are not limited by the described action sequence, because according to the embodiments of this specification, certain steps can be carried out in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the embodiments of this specification.

[0046] In the above embodiments, the descriptions of each embodiment have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0047] The preferred embodiments of this specification disclosed above are only used to help explain this specification. The optional embodiments do not describe all the details in detail, nor do they limit the invention to only the specific implementation manners. Obviously, according to the content of the embodiments of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the embodiments of this specification, so that those skilled in the art can well understand and utilize this specification. This specification is only limited by the claims and their full scope and equivalents.

Claims

1. A steam turbine emergency trip system, characterized in that: include: AST solenoid valves and intermediate relays, the number of the intermediate relays is N times the number of the AST solenoid valves, and N is an integer not less than 2; The AST solenoid valve controls the EH oil circuit in a dual-channel, series-parallel structure. After each N intermediate relays are connected in parallel, they are connected in series in the power supply circuit of each corresponding AST solenoid valve.

2. The steam turbine emergency shutdown system according to claim 1, characterized in that: Also includes: A current transmitter and a voltage transmitter are respectively provided for the AST solenoid valve coil of each of the AST solenoid valves; The current transmitter is used to collect the working current of the AST solenoid valve coil, and the current transmitter is used to collect the working voltage of the AST solenoid valve coil.

3. The steam turbine emergency shutdown system according to claim 1, characterized in that: Also includes: Temperature collecting blocks and micro thermal resistors are respectively installed on the shutoff block of the steam turbine emergency shutoff system, the oil inlet pipe and the oil return pipe of the steam turbine high-pressure fire-resistant oil system to measure the oil inlet temperature and the oil return temperature.

4. The steam turbine emergency shutdown system according to claim 3, characterized in that: Also includes: The internal leakage identification module connected to the temperature collection block and the micro thermal resistor is used to collect the oil inlet temperature and the oil return temperature, and to perform internal leakage judgment on the cutoff block according to the deviation between the oil inlet temperature and the oil return temperature to generate an internal leakage identification result.

5. The steam turbine emergency shutdown system according to claim 1, characterized in that: Also includes: A DCS analysis system, used to collect the working status information of each component in the steam turbine emergency shutdown system, and to perform status monitoring and alarm according to the working status information; The working status information includes: the power supply status of the AST solenoid valve, the working status, working current, working voltage of the AST solenoid valve coil, and one or more of the internal leakage identification results.

6. The steam turbine emergency shutdown system according to claim 1, characterized in that: Also includes: A heat dissipation device is installed for the AST solenoid valve coil of each of the AST solenoid valves.

7. The steam turbine emergency shutdown system according to claim 6, characterized in that: The heat dissipation device is installed on the working heating surface of the AST solenoid valve coil.

8. The steam turbine emergency shutdown system according to claim 7, characterized in that: A thin-film patch temperature measuring element is embedded in the mounting interface between the heat dissipation device and the AST solenoid valve coil, which is used to monitor the coil temperature.

9. The steam turbine emergency shutdown system according to claim 6, characterized in that: A fan is installed on the top of the heat dissipation device to increase the heat dissipation speed.

10. The steam turbine emergency shutdown system according to claim 9, characterized in that: The power supply voltage of the fan is selected to be 12 volts DC and 0.5 amperes.

Images