Steam turbine protection circuit and system
Patent Information
- Application Number
- CN202411533104.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2025-03-11
Smart Images
Figure CN119593819A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of steam turbine protection, and in particular, to a steam turbine protection circuit and system. Background Art
[0002] In the current turbine protection system, sensors are usually installed to monitor the shaft displacement. Generally, one sensor is installed on each side of the turbine thrust bearing to measure the axial displacement. The data of these sensors are transmitted to the TSI (Turbine Supervisory Instrumentation) turbine monitoring framework system, and the TSI system outputs two protection action signals to the DCS (Distributed Control System) distributed control system. In the DCS system, the protection logic relationship is "two out of one", that is, when any of the two protection action signals is activated, the unit protection action is performed. This design has the risk of false protection action, which may cause unnecessary shutdowns and reduce production efficiency. Summary of the invention
[0003] The purpose of the present disclosure is to provide a steam turbine protection circuit and system, which can reduce the probability of malfunction of steam turbine protection, thereby reducing unnecessary shutdowns and improving production efficiency.
[0004] In order to achieve the above-mentioned object, according to a first aspect of an embodiment of the present disclosure, a steam turbine protection circuit is provided, comprising: a steam turbine shaft displacement detection circuit, a one-to-three transmission circuit and a three-to-two circuit connected to each other;
[0005] The turbine shaft displacement detection circuit is used to detect whether the shaft displacement of the turbine exceeds the safety distance threshold, and to send a shaft displacement exceeding threshold signal when the shaft displacement of the turbine exceeds the safety distance threshold;
[0006] The one-to-three transmission circuit is used to divide the shaft displacement exceeding standard signal into three signals and transmit them to the three-to-two circuit, wherein the three signals include: a first shaft displacement exceeding standard signal, a second shaft displacement exceeding standard signal and a third shaft displacement exceeding standard signal;
[0007] The three-to-two circuit is used to output a turbine shaft displacement protection signal when any two of the three signals are true.
[0008] Optionally, the turbine shaft displacement detection circuit comprises: a first shaft displacement sensor, a second shaft displacement sensor, a third shaft displacement sensor, a fourth shaft displacement sensor, a first OR gate, a second OR gate and a first AND gate;
[0009] The first axis displacement sensor and the second axis displacement sensor are connected to the first input terminal and the second input terminal of the first OR gate respectively, and the output terminal of the first OR gate is connected to the first input terminal of the first AND gate;
[0010] The third axis displacement sensor and the fourth axis displacement sensor are connected to the first input terminal and the second input terminal of the second OR gate respectively, and the output terminal of the second OR gate is connected to the second input terminal of the first AND gate;
[0011] The output end of the first AND gate is connected to the three-to-two circuit for outputting the shaft displacement exceeding standard signal.
[0012] Optionally, the one-to-three transmission circuit comprises: a first relay, a second relay and a third relay connected in parallel;
[0013] The input end of the first relay is connected to the output end of the turbine shaft displacement detection circuit, and the output end of the first relay is connected to the input end of the three-select-two circuit, so as to output true when the first shaft displacement exceeding standard signal is true;
[0014] The input end of the second relay is connected to the output end of the turbine shaft displacement detection circuit, and the output end of the second relay is connected to the input end of the three-select-two circuit, so as to output true when the second shaft displacement exceeding standard signal is true;
[0015] The input end of the third relay is connected to the output end of the turbine shaft displacement detection circuit, and the output end of the third relay is connected to the input end of the three-select-two circuit, so as to output true when the third shaft displacement exceeding standard signal is true.
[0016] Optionally, the three-choose-two circuit includes: a second AND gate, a third AND gate, a fourth AND gate and a third OR gate;
[0017] The first input end of the second AND gate is connected to the output end of the third relay of the one-to-three transmission circuit, the second input end of the second AND gate is connected to the output end of the first relay of the one-to-three transmission circuit, and the output end of the second AND gate is connected to the first input end of the third OR gate;
[0018] The first input end of the third AND gate is connected to the output end of the first relay of the one-to-three transmission circuit, the second input end of the third AND gate is connected to the output end of the second relay of the one-to-three transmission circuit, and the output end of the third AND gate is connected to the second input end of the third OR gate;
[0019] The first input end of the fourth AND gate is connected to the output end of the third relay of the one-to-three transmission circuit, the second input end of the fourth AND gate is connected to the output end of the second relay of the one-to-three transmission circuit, and the output end of the fourth AND gate is connected to the third input end of the third OR gate;
[0020] The output end of the third OR gate is used to output the turbine shaft displacement protection signal.
[0021] Optionally, the three-choose-two circuit further includes a delay device;
[0022] The input end of the delay device is connected to the output end of the third OR gate, and the output end of the delay device is used to output the turbine shaft displacement protection signal after a preset delay time.
[0023] Optionally, the preset delay time includes 0.2 seconds.
[0024] Optionally, the three-choose-two circuit further includes a fifth AND gate;
[0025] The first input end of the fifth AND gate is connected to the output end of the third OR gate, the second input end of the fifth AND gate is connected to the protection pressure plate signal, and the output end of the fifth AND gate is used to output the turbine shaft displacement protection signal.
[0026] Optionally, the protection pressure plate signal is output as true when the protection pressure plate is engaged;
[0027] The protection pressure plate signal is output as false when the protection pressure plate is not engaged.
[0028] Optionally, the turbine shaft displacement detection circuit is arranged on the turbine side;
[0029] The one-to-three transmission circuit is arranged on the transmission line side, and the transmission line connects the steam turbine and the DCS equipment;
[0030] The three-choice-two circuit is arranged on the DCS device side.
[0031] According to a second aspect of an embodiment of the present disclosure, a steam turbine protection system is provided, comprising: a steam turbine, a transmission line and a DCS device connected to each other, the steam turbine comprising the steam turbine shaft displacement detection circuit described in any one of the first aspects, the transmission line comprising the one-to-three transmission circuit described in any one of the first aspects, and the DCS device comprising the three-to-two circuit described in any one of the first aspects.
[0032] In summary, the disclosed embodiment provides a steam turbine protection circuit, including: a steam turbine shaft displacement detection circuit, a one-to-three transmission circuit, and a three-to-two circuit connected to each other; the steam turbine shaft displacement detection circuit is used to detect whether the shaft displacement of the steam turbine exceeds the safety distance threshold, and when the shaft displacement of the steam turbine exceeds the safety distance threshold, a shaft displacement exceeding standard signal is issued; the one-to-three transmission circuit is used to divide the shaft displacement exceeding standard signal into three signals, and transmit them to the three-to-two circuit, the three signals include: a first shaft displacement exceeding standard signal, a second shaft displacement exceeding standard signal, and a third shaft displacement exceeding standard signal; the three-to-two circuit is used to output a steam turbine shaft displacement protection signal when any two of the three signals are true. The disclosed embodiment can reduce the probability of malfunction of the steam turbine protection, thereby reducing unnecessary shutdowns and improving production efficiency.
[0033] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:
[0035] Figure 1 is a schematic diagram of a steam turbine protection circuit according to an exemplary embodiment.
[0036] Figure 2 is a schematic diagram of a steam turbine shaft displacement detection circuit according to an exemplary embodiment.
[0037] Figure 3 The figure is a schematic diagram of a one-to-three transmission circuit according to an exemplary embodiment.
[0038] Figure 4 The figure is a schematic diagram of a three-choose-two circuit according to an exemplary embodiment.
[0039] Figure 5 The figure is a schematic diagram of a three-choose-two circuit according to an exemplary embodiment.
[0040] Figure 6 The figure is a schematic diagram of a three-choose-two circuit according to an exemplary embodiment.
[0041] Figure 7 The figure is a schematic diagram of a three-choose-two circuit according to an exemplary embodiment.
[0042] Figure 8 It is a block diagram of a DCS device according to an exemplary embodiment.
[0043] Fig. 9 is a block diagram of a steam turbine protection system according to an exemplary embodiment. DETAILED DESCRIPTION
[0044] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.
[0045] It should be understood that the term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description.
[0046] It should be noted that the concepts of "first", "second", etc. mentioned in the present disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units. The modifications of "one" and "multiple" mentioned in the present disclosure are illustrative and not restrictive. Those skilled in the art should understand that unless otherwise clearly indicated in the context, they should be understood as "one or more". In the description of the present disclosure, unless otherwise specified, "multiple" refers to two or more than two, and other quantifiers are similar; "at least one item", "one item or multiple items" or similar expressions refer to any combination of these items, including any combination of single items or plural items.
[0047] Although operations or steps are described in a specific order in the drawings in the embodiments of the present disclosure, it should not be understood that it is required to perform these operations or steps in the specific order shown or in a serial order, or to perform all the operations or steps shown to obtain the desired results. In the embodiments of the present disclosure, these operations or steps can be performed in series; these operations or steps can also be performed in parallel; or some of these operations or steps can be performed.
[0048] The names of the messages or information exchanged between multiple devices in the embodiments of the present disclosure are only for illustrative purposes and are not used to limit the scope of these messages or information. It is understandable that before using the technical solutions disclosed in the embodiments of the present disclosure, the type, scope of use, and usage scenarios of the personal information involved in the present disclosure should be informed to the user in an appropriate manner in accordance with relevant laws and regulations and the user's authorization should be obtained.
[0049] First, the application scenario of the present disclosure is explained. The applicant has found that in the current turbine protection system, sensors are usually installed to monitor the shaft displacement. Generally, one sensor is installed on the left and right sides of the turbine thrust bearing to measure the axial displacement. The signals of these two sensors are transmitted to the TSI (Turbine Supervisory Instrumentation) turbine monitoring framework system after phase OR, and the TSI system outputs two protection action signals to the DCS (Distributed Control System) distributed control system. In the DCS system, the protection logic relationship is "two out of one", that is, when any of the two protection action signals is actuated, the unit protection action is performed. This design has the risk of false protection action, which may cause unnecessary shutdowns and reduce production efficiency.
[0050] In addition, if both sensors installed on the turbine side fail, it is easy to cause turbine protection failure and the reliability is not high.
[0051] Therefore, there is an urgent need for a steam turbine protection circuit and system that has high reliability in detecting the shaft displacement of a steam turbine and can reduce malfunction of steam turbine protection. The present disclosure is described below in conjunction with specific embodiments.
[0052] Figure 1 FIG. 1 is a schematic diagram of a steam turbine protection circuit according to an exemplary embodiment. Figure 1 As shown, an embodiment of the present disclosure provides a steam turbine protection circuit, comprising: a steam turbine shaft displacement detection circuit 10, a one-to-three transmission circuit 20 and a three-to-two circuit 30 connected to each other.
[0053] The turbine shaft displacement detection circuit 10 is used to detect whether the turbine shaft displacement exceeds the safety distance threshold, and to send a shaft displacement exceeding signal when the turbine shaft displacement exceeds the safety distance threshold. For example, the safety distance threshold may be 0.5 mm.
[0054] The one-to-three transmission circuit 20 is used to divide the shaft displacement exceeding standard signal into three signals and transmit them to the three-to-two circuit 30. The three signals include: the first shaft displacement exceeding standard signal (not shown in the figure), the second shaft displacement exceeding standard signal (not shown in the figure) and the third shaft displacement exceeding standard signal (not shown in the figure).
[0055] The three-choose-two circuit 30 is used to output a turbine shaft displacement protection signal when any two of the three signals, namely, the first shaft displacement exceeding standard signal, the second shaft displacement exceeding standard signal and the third shaft displacement exceeding standard signal, are true. Thus, compared with the traditional shaft displacement exceeding standard signal two-choose-one circuit, the shaft displacement exceeding standard signal three-choose-two circuit can improve the anti-interference ability, thereby reducing the probability of turbine protection malfunction, thereby reducing unnecessary shutdowns and improving the production efficiency of the power plant.
[0056] In summary, the disclosed embodiment provides a steam turbine protection circuit, including: a steam turbine shaft displacement detection circuit, a one-to-three transmission circuit, and a three-to-two circuit connected to each other; the steam turbine shaft displacement detection circuit is used to detect whether the shaft displacement of the steam turbine exceeds the safety distance threshold, and when the shaft displacement of the steam turbine exceeds the safety distance threshold, a shaft displacement exceeding standard signal is issued; the one-to-three transmission circuit is used to divide the shaft displacement exceeding standard signal into three signals, and transmit them to the three-to-two circuit, the three signals include: a first shaft displacement exceeding standard signal, a second shaft displacement exceeding standard signal, and a third shaft displacement exceeding standard signal; the three-to-two circuit is used to output a steam turbine shaft displacement protection signal when any two of the three signals are true. The disclosed embodiment can reduce the probability of malfunction of the steam turbine protection, thereby reducing unnecessary shutdowns and improving production efficiency.
[0057] Figure 2 FIG. 1 is a schematic diagram of a steam turbine shaft displacement detection circuit according to an exemplary embodiment. Figure 2 As shown, the turbine shaft displacement detection circuit 10 includes: a first shaft displacement sensor 101 , a second shaft displacement sensor 102 , a third shaft displacement sensor 103 , a fourth shaft displacement sensor 104 , a first OR gate 105 , a second OR gate 106 and a first AND gate 107 .
[0058] The first axis displacement sensor 101 and the second axis displacement sensor 102 are connected to the first input terminal and the second input terminal of the first OR gate 105 respectively, and the output terminal of the first OR gate 105 is connected to the first input terminal of the first AND gate 107 .
[0059] The third axis displacement sensor 103 and the fourth axis displacement sensor 104 are connected to the first input terminal and the second input terminal of the second OR gate 106 respectively, and the output terminal of the second OR gate 106 is connected to the second input terminal of the first AND gate 107 .
[0060] The output end of the first AND gate 107 is connected to the three-to-two circuit 30 for outputting a shaft displacement exceeding standard signal.
[0061] In this way, since the number of shaft displacement sensors increases to 4, the probability of all four sensors failing is much lower than the probability of two sensors failing. Compared with the traditional detection circuit with only two shaft displacement sensors, the turbine shaft displacement detection circuit 10 can improve the reliability of turbine shaft displacement detection, effectively reduce the probability of turbine protection failure, reduce the probability of turbine damage, and thus reduce losses.
[0062] Figure 3 FIG. 1 is a schematic diagram of a one-to-three transmission circuit according to an exemplary embodiment. Figure 3As shown, the one-to-three transmission circuit 20 includes: a first relay K1, a second relay K2 and a third relay K3 connected in parallel.
[0063] The input end of the first relay K1 is connected to the output end of the turbine shaft displacement detection circuit 10, and the output end of the first relay K1 is connected to the input end of the three-to-two circuit 30, which is used to actuate the knife and output the first action protection signal as true when the first shaft displacement exceeding standard signal is true.
[0064] The input end of the second relay K2 is connected to the output end of the turbine shaft displacement detection circuit 10, and the output end of the second relay K2 is connected to the input end of the three-select-two circuit 30, which is used to actuate the knife and output the second action protection signal as true when the second shaft displacement exceeds the standard signal is true.
[0065] The input end of the third relay K3 is connected to the output end of the turbine shaft displacement detection circuit 10, and the output end of the third relay K3 is connected to the input end of the three-to-two circuit 30, so as to actuate the knife and output the third action protection signal as true when the third shaft displacement exceeding standard signal is true.
[0066] Figure 4 FIG. 1 is a schematic diagram of a three-choose-two circuit according to an exemplary embodiment. Figure 4 As shown, the three-choose-two circuit 30 includes: a second AND gate 301 , a third AND gate 302 , a fourth AND gate 303 and a third OR gate 304 .
[0067] The first input end of the second AND gate 301 is connected to the output end of the third relay K3 of the one-to-three transmission circuit 20, the second input end of the second AND gate 301 is connected to the output end of the first relay K1 of the one-to-three transmission circuit 20, and the output end of the second AND gate 301 is connected to the first input end of the third OR gate 304.
[0068] The first input end of the third AND gate 302 is connected to the output end of the first relay K1 of the one-to-three transmission circuit 20, the second input end of the third AND gate 302 is connected to the output end of the second relay K2 of the one-to-three transmission circuit 20, and the output end of the third AND gate 302 is connected to the second input end of the third OR gate 304.
[0069] A first input of the fourth AND gate 303 is connected to the output of the third relay K3 of the one-to-three transmission circuit 20 , a second input of the fourth AND gate 303 is connected to the output of the second relay K2 of the one-to-three transmission circuit 20 , and an output of the fourth AND gate 303 is connected to the third input of the third OR gate 304 .
[0070] The output end of the third OR gate 304 is used to output a turbine shaft displacement protection signal.
[0071] In this way, only when any two of the first action protection signal, the second action protection signal and the third action protection signal are true, the output of the third OR gate 304 is true, the turbine shaft displacement protection signal is true, and the turbine protection action can take effect. Compared with the traditional two-choose-one circuit, the three-choose-two circuit 30 can effectively reduce the turbine protection misoperation caused by the relay being interfered with and misoperated, thereby reducing the probability of turbine protection misoperation, thereby reducing unnecessary shutdowns and improving production efficiency.
[0072] Figure 5 FIG. 1 is a schematic diagram of a three-choose-two circuit according to an exemplary embodiment. Figure 5 As shown, the three-to-two circuit 30 further includes a delay device 305 .
[0073] The input end of the delayer 305 is connected to the output end of the third OR gate 304, and the output end of the delayer 305 is used to output a turbine shaft displacement protection signal after a preset delay time.
[0074] In some embodiments, the preset delay time may be 0.2 seconds, and the preset delay time may be manually adjusted according to actual conditions.
[0075] In this way, the stability of the protection circuit can be enhanced.
[0076] Figure 6 FIG. 1 is a schematic diagram of a three-choose-two circuit according to an exemplary embodiment. Figure 6 As shown, the three-to-two circuit 30 further includes a fifth AND gate 306 .
[0077] A first input end of the fifth AND gate 306 is connected to an output end of the third OR gate 304 , a second input end of the fifth AND gate 306 is connected to a protection pressure plate signal, and an output end of the fifth AND gate 306 is used to output a turbine shaft displacement protection signal.
[0078] In some embodiments, the protection pressure plate signal is output as true when the protection pressure plate is engaged, and is output as false when the protection pressure plate is not engaged.
[0079] In this way, it is convenient to perform daily maintenance and inspection on the circuit when the protection pressure plate is put into operation without causing malfunction of the unit.
[0080] Figure 7 FIG. 1 is a schematic diagram of a three-choose-two circuit according to an exemplary embodiment. Figure 7 As shown, the first input end of the fifth AND gate 306 is connected to the output end of the delayer 305, the second input end of the fifth AND gate 306 is connected to the protection pressure plate signal, and the output end of the fifth AND gate 306 is used to output the turbine shaft displacement protection signal.
[0081] This can further enhance the stability of the protection circuit.
[0082] In some embodiments, the turbine shaft displacement detection circuit 10 may be disposed on the turbine side.
[0083] The one-to-three transmission circuit 20 may be arranged on the transmission line side, and the transmission line connects the steam turbine and the DCS equipment.
[0084] The three-choice-two circuit 30 may be provided on the DCS device side.
[0085] In summary, the disclosed embodiment provides a steam turbine protection circuit, including: a steam turbine shaft displacement detection circuit, a one-to-three transmission circuit, and a three-to-two circuit connected to each other; the steam turbine shaft displacement detection circuit is used to detect whether the shaft displacement of the steam turbine exceeds the safety distance threshold, and when the shaft displacement of the steam turbine exceeds the safety distance threshold, a shaft displacement exceeding standard signal is issued; the one-to-three transmission circuit is used to divide the shaft displacement exceeding standard signal into three signals, and transmit them to the three-to-two circuit, the three signals include: a first shaft displacement exceeding standard signal, a second shaft displacement exceeding standard signal, and a third shaft displacement exceeding standard signal; the three-to-two circuit is used to output a steam turbine shaft displacement protection signal when any two of the three signals are true. The disclosed embodiment can reduce the probability of malfunction of the steam turbine protection, thereby reducing unnecessary shutdowns and improving production efficiency.
[0086] Figure 8 FIG. 1 is a block diagram of a DCS device according to an exemplary embodiment. Figure 8 As shown, an embodiment of the present disclosure provides a DCS device 300, including any of the three-choose-two circuits 30 described in the above embodiments. The DCS device 300 may include: a processor 301, a memory 302. The DCS device 300 may also include one or more of a multimedia component 303, an input / output (I / O) interface 304, and a communication component 305.
[0087] The processor 301 is used to control the overall operation of the DCS device 300, and the memory 302 is used to store various types of data to support the operation of the DCS device 300. These data may include, for example, instructions for any application or method used to operate on the DCS device 300, and application-related data, such as contact data, sent and received messages, pictures, audio, video, etc. The memory 302 may be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, disk or optical disk. The multimedia component 303 may include a screen and an audio component. The screen may be, for example, a touch screen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signal may be further stored in the memory 302 or sent through the communication component 305. The audio component also includes at least one speaker for outputting audio signals. The I / O interface 304 provides an interface between the processor 301 and other interface modules, and the above-mentioned other interface modules may be keyboards, mice, buttons, etc. These buttons may be virtual buttons or physical buttons. The communication component 305 is used for wired or wireless communication between the DCS device 300 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, NB-IOT, eMTC, or other 5G, etc., or a combination of one or more of them, is not limited here. Therefore, the corresponding communication component 305 may include: Wi-Fi module, Bluetooth module, NFC module, etc.
[0088] In an exemplary embodiment, the DCS device 300 may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components.
[0089] In another exemplary embodiment, a computer-readable storage medium including program instructions is further provided. For example, the computer-readable storage medium may be the memory 302 including program instructions, and the program instructions may be executed by the processor 301 of the DCS device 300 .
[0090] Fig. 9 FIG. 1 is a block diagram of a steam turbine protection system according to an exemplary embodiment. Fig. 9 As shown, the embodiment of the present disclosure provides a steam turbine protection system, comprising: a steam turbine 100, a transmission line 200 and a DCS device 300 connected to each other, the steam turbine 100 comprises the steam turbine shaft displacement detection circuit 10 described in any of the above embodiments, the transmission line 200 comprises the one-to-three transmission circuit 20 described in any of the above embodiments, and the DCS device 300 comprises the three-to-two circuit 30 described in any of the above embodiments. The system can reduce the probability of malfunction of the steam turbine protection, thereby reducing unnecessary shutdowns and improving production efficiency.
[0091] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.
[0092] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.
[0093] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.
Claims
1. A steam turbine protection circuit, characterized in that: include: A steam turbine shaft displacement detection circuit, a one-to-three transmission circuit and a three-to-two circuit connected to each other; The turbine shaft displacement detection circuit is used to detect whether the shaft displacement of the turbine exceeds the safety distance threshold, and to send a shaft displacement exceeding threshold signal when the shaft displacement of the turbine exceeds the safety distance threshold; The one-to-three transmission circuit is used to divide the shaft displacement exceeding standard signal into three signals and transmit them to the three-to-two circuit, wherein the three signals include: a first shaft displacement exceeding standard signal, a second shaft displacement exceeding standard signal and a third shaft displacement exceeding standard signal; The three-to-two circuit is used to output a turbine shaft displacement protection signal when any two of the three signals are true.
2. The steam turbine protection circuit according to claim 1, characterized in that: The turbine shaft displacement detection circuit comprises: a first shaft displacement sensor, a second shaft displacement sensor, a third shaft displacement sensor, a fourth shaft displacement sensor, a first OR gate, a second OR gate and a first AND gate; The first axis displacement sensor and the second axis displacement sensor are connected to the first input terminal and the second input terminal of the first OR gate respectively, and the output terminal of the first OR gate is connected to the first input terminal of the first AND gate; The third axis displacement sensor and the fourth axis displacement sensor are connected to the first input terminal and the second input terminal of the second OR gate respectively, and the output terminal of the second OR gate is connected to the second input terminal of the first AND gate; The output end of the first AND gate is connected to the three-to-two circuit for outputting the shaft displacement exceeding standard signal.
3. The steam turbine protection circuit according to claim 1, characterized in that: The one-to-three transmission circuit comprises: a first relay, a second relay and a third relay connected in parallel; The input end of the first relay is connected to the output end of the turbine shaft displacement detection circuit, and the output end of the first relay is connected to the input end of the three-select-two circuit, so as to output true when the first shaft displacement exceeding standard signal is true; The input end of the second relay is connected to the output end of the turbine shaft displacement detection circuit, and the output end of the second relay is connected to the input end of the three-select-two circuit, so as to output true when the second shaft displacement exceeding standard signal is true; The input end of the third relay is connected to the output end of the turbine shaft displacement detection circuit, and the output end of the third relay is connected to the input end of the three-select-two circuit, so as to output true when the third shaft displacement exceeding standard signal is true.
4. The steam turbine protection circuit according to claim 1, characterized in that: The three-choose-two circuit comprises: a second AND gate, a third AND gate, a fourth AND gate and a third OR gate; The first input end of the second AND gate is connected to the output end of the third relay of the one-to-three transmission circuit, the second input end of the second AND gate is connected to the output end of the first relay of the one-to-three transmission circuit, and the output end of the second AND gate is connected to the first input end of the third OR gate; The first input end of the third AND gate is connected to the output end of the first relay of the one-to-three transmission circuit, the second input end of the third AND gate is connected to the output end of the second relay of the one-to-three transmission circuit, and the output end of the third AND gate is connected to the second input end of the third OR gate; The first input end of the fourth AND gate is connected to the output end of the third relay of the one-to-three transmission circuit, the second input end of the fourth AND gate is connected to the output end of the second relay of the one-to-three transmission circuit, and the output end of the fourth AND gate is connected to the third input end of the third OR gate; The output end of the third OR gate is used to output the turbine shaft displacement protection signal.
5. The steam turbine protection circuit according to claim 4, characterized in that: The three-choose-two circuit also includes a delay device; The input end of the delay device is connected to the output end of the third OR gate, and the output end of the delay device is used to output the turbine shaft displacement protection signal after a preset delay time.
6. The steam turbine protection circuit according to claim 5, characterized in that: The preset delay time includes 0.2 seconds.
7. The steam turbine protection circuit according to claim 4, characterized in that: The three-choose-two circuit also includes a fifth AND gate; The first input end of the fifth AND gate is connected to the output end of the third OR gate, the second input end of the fifth AND gate is connected to the protection pressure plate signal, and the output end of the fifth AND gate is used to output the turbine shaft displacement protection signal.
8. The steam turbine protection circuit according to claim 7, characterized in that: The protection pressure plate signal is output as true when the protection pressure plate is in operation; The protection pressure plate signal is output as false when the protection pressure plate is not engaged.
9. The steam turbine protection circuit according to any one of claims 1 to 8, characterized in that: The turbine shaft displacement detection circuit is arranged on the turbine side; The one-to-three transmission circuit is arranged on the transmission line side, and the transmission line connects the steam turbine and the DCS equipment; The three-choice-two circuit is arranged on the DCS device side.
10. A steam turbine protection system, characterized in that: include: A steam turbine, a transmission line and a DCS device connected to each other, wherein the steam turbine comprises the turbine shaft displacement detection circuit described in any one of claims 1-9, the transmission line comprises the one-to-three transmission circuit described in any one of claims 1-9, and the DCS device comprises the three-to-two circuit described in any one of claims 1-9.