Safe shutdown protection method after steam turbine generator splitting and electric power system
By using signal acquisition and logic processing methods, and utilizing the three-phase normally closed contacts and time-delay relays of the grid-connected switch, the problem of safe shutdown when the generator is disconnected first is solved, achieving efficient and reliable safe shutdown protection and reducing costs.
Patent Information
- Application Number
- CN202511513771.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-22
- Publication Date
- 2026-01-23
AI Technical Summary
When the generator is disconnected first, the existing technology that relies on adding equipment has the problems of high cost and inability to act in a timely manner, which makes it difficult to safely shut down the generator.
By using signal acquisition, logic processing, and protection execution methods, and leveraging the three-phase normally closed contacts and logic judgment of the grid-connected switch, combined with time-delay relays and hard pressure plates, safe shutdown protection is achieved, avoiding the need for additional equipment and eliminating redundant components in the structure.
It improves the reliability and cost-effectiveness of safety shutdown protection without adding equipment, and the structural modification work is minimal and easy to implement.
Smart Images
Figure CN121395490A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] Embodiments of the present application relate to the technical field of generator safety control. More particularly, the present application relates to a method for safe shutdown protection after a turbine generator is tripped and a power system. BACKGROUND
[0002] In the operation of a power system, the safe and stable operation of a generator as a core device is directly related to the reliable power supply of the power grid, so the safety control technology of the generator is of vital importance in the application of thermal power generation, hydroelectric power generation, new energy power generation and other power generation fields. Generally, the generator-transformer group protection of a 200MW capacity class thermal power unit is configured with a program reverse power protection. When normally shutting down, the generator can be tripped from the system after confirming that the active and reactive power of the generator is reduced to zero, or the generator is tripped by manually tripping the turbine. However, in the case of generator tripping first, the safe shutdown is at risk. At this time, due to the generator tripping first, the program reverse power protection action condition is not met, and the unit cannot be stopped in time, which may cause the generator to trip first and the protection to fail to act on the generator de-excitation and switch the station service power, resulting in over-excitation of the generator and unsuccessful switching of the station service power. If the station service power switching is unsuccessful, it may also be a problem whether the diesel generator can be started in an emergency and provide unit security power, thereby challenging the safe shutdown of the unit. The turbine generator tripping refers to disconnecting the turbine generator from the power system to stop the turbine generator from delivering power to the power grid. This operation is usually performed when the unit encounters a fault. During the tripping process, the circuit breaker of the generator is disconnected, and the load of the turbine is also disconnected.
[0003] In the prior art, in the case of the generator tripping first, the "unit power sudden drop machine tripping device" is mainly relied on, such as the PCS-985UP type to realize the protection function. The device is suitable for the fast shutdown control of large-scale turbine units in the case of positive power sudden drop. The device uses electrical characteristics such as current sudden drop, voltage sudden increase, frequency sudden increase, active power sudden drop, etc. in the positive power sudden drop process to form a logic criterion. After the power sudden drop machine tripping device acts, the station service power is switched and the generator is de-excited, and the emergency trip protection "ETS" of the turbine is also acted on and the boiler interlock trip is started. However, this scheme needs to increase the equipment, which increases the investment, and the cost is about 600,000 yuan. SUMMARY
[0004] In order to solve the generator safe shutdown technical problems in special cases such as generator decoupling mentioned above, the application provides a steam turbine generator decoupling safe shutdown protection method and a steam turbine generator power system applied to the method, the method and the steam turbine generator power system do not need to add new equipment, so that the entire power system has no redundant components in structure, and the program of the safety control device does not need to be modified, the structural modification workload is small, thereby the cost is reduced, the method is easy to implement, and the safety shutdown protection effect is more reliable.
[0005] According to a first aspect of the application, a steam turbine generator decoupling safe shutdown protection method is provided, comprising the following steps: step one, signal acquisition, further comprising: acquiring signals through A, B and C three-phase standby normally closed contact points of two grid-connected switches, wherein the normally closed contact points are closed when the grid-connected switches are disconnected; step two, first-level logic processing, further comprising: performing two-out-of-three logic judgment on the A, B and C three-phase normally closed contact point signals of a single grid-connected switch, and outputting a disconnection signal of the grid-connected switch when at least two normally closed contact points are turned on; step three, second-level logic processing, further comprising: performing AND logic judgment on the disconnection signals of the two grid-connected switches, and outputting a generator decoupling signal; and step four, protection execution, further comprising: connecting the generator decoupling signal to a delay relay through a standby protection hard pressure plate, and executing safe shutdown protection through a generator-transformer group non-electric quantity protection cabinet.
[0006] In some embodiments, the method further comprises signal transmission, which comprises: connecting each execution element in steps one, two, three and four by a cable; and connecting an intermediate relay in series in the cable.
[0007] In some embodiments, the action voltage of the intermediate relay is set to 55%-70% of the rated DC voltage, and the action power is greater than or equal to 5W.
[0008] In some embodiments, in the signal transmission step, the intermediate relay is installed at the cable terminal close to the non-electric quantity protection cabinet.
[0009] In some embodiments, the cable adopts a cable with a cross-sectional model of ZRC-KYJYP2-23-0.45 / 0.75, 4*2.5mm.
[0010] In some embodiments, in step four, the action delay of the delay relay is set to 50-100ms.
[0011] In some embodiments, the first-level logic processing is realized by a relay combination circuit, and when at least two normally closed contact points are turned on, the relay coil is electrified to output a switch disconnection signal.
[0012] In some embodiments, in step four, the backup protection hard panel adopts a mechanical hard panel, and is connected in series between the generator split signal and the time delay relay.
[0013] In some embodiments, in the signal acquisition step, the A, B, C three-phase backup normally closed contact is a copper conductive contact.
[0014] According to a second aspect of the present application, a steam turbine generator power system is provided, which applies the above-mentioned safe shutdown protection method, comprising: a signal acquisition module, which comprises two grid switches, each of which is provided with A, B, C three-phase backup normally closed contacts; a logic processing module connected with the signal acquisition module, the logic processing module comprising a first level logic unit and a second level logic unit, the first level logic unit being used for performing a two-out-of-three logic on the A, B, C three-phase normally closed contact signals of a single grid switch, and the second level logic unit being used for performing an AND logic on the disconnection signals of the two grid switches; a protection execution module connected with the logic processing module, the protection execution module comprising a generator-transformer group non-electric quantity protection cabinet, the non-electric quantity protection cabinet being provided with a backup protection hard panel and a time delay relay; a hardware transmission component connected with the signal acquisition module, the logic processing module and the protection execution module; wherein the first level logic unit is used for judging and outputting the disconnection signal of the grid switch, the second level logic unit is used for judging and outputting the generator split signal, and the generator split signal is connected to the time delay relay through the backup protection hard panel.
[0015] Through the safe shutdown protection method provided above, the following advantages are achieved: 1) the signal acquisition reuses the original backup contact of the grid switch, and the protection execution reuses the backup hard panel of the non-electric quantity protection cabinet, without the need for adding new equipment, so that the entire power system has no redundant components in structure, thereby reducing the cost. 2) the three-phase normally closed contact and the "3-out-of-2 logic" structure of the signal acquisition can effectively judge the disconnection state of the switch; the hardware transmission can adapt to long-distance transmission and has strong anti-interference ability; the time delay relay can also effectively avoid signal jitter misoperation, so that the entire power system is more reliable in the effect of safe shutdown protection. 3) only hardware wiring modification is needed, without the need for modifying the program of the safety control device, so that the structural modification workload is small and easy to implement. BRIEF DESCRIPTION OF DRAWINGS
[0016] The above and other objects, features and advantages of the exemplary embodiments of the present application will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which several embodiments of the present application are shown by way of example, and wherein like reference numerals refer to like elements throughout. In the drawings:
[0017] Figure 1 A step flow chart of the safe shutdown protection method for the steam turbine generator after split of the present application embodiment;
[0018] Figure 2 A three-phase "3 out of 2" logic diagram for one of the two grid-connected switches of a steam turbine generator power system according to an embodiment of the present application;
[0019] Figure 3 A three-phase "3 out of 2" terminal diagram for one of the two grid-connected switches of a steam turbine generator power system according to an embodiment of the present application;
[0020] Figure 4 A generator trip signal terminal arrangement for a steam turbine generator power system according to an embodiment of the present application. DETAILED DESCRIPTION
[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.
[0022] Figure 1 A step diagram of a safe shutdown protection method 100 for a steam turbine generator trip according to an embodiment of the present application is shown. Figures 2 to 4 A three-phase "3 out of 2" logic diagram, a terminal diagram, and a generator trip signal terminal arrangement for one of the two grid-connected switches of a steam turbine generator power system according to an embodiment of the present application are shown respectively. In combination with Figures 1 to 4 As shown, the safe shutdown protection method 100 for a steam turbine generator trip, comprises the following steps:
[0023] Step one S1, signal acquisition, further comprising: acquiring signals through A, B, C three-phase standby normally closed contacts of the two grid-connected switches, wherein the normally closed contacts are closed in the case of disconnection of the grid-connected switches;
[0024] Step two S2, first-level logic processing, further comprising: performing a three-out-of-two logic judgment on the A, B, C three-phase normally closed contact signals of a single grid-connected switch, and outputting a disconnection signal of the grid-connected switch when at least two normally closed contacts are turned on;
[0025] Step three S3, second-level logic processing, further comprising: performing an AND logic judgment on the disconnection signals of the two grid-connected switches, and outputting a generator trip signal;
[0026] Step four S4, protection execution, further comprising: inputting the generator trip signal into a delay relay through a standby protection hard panel, and executing a safe shutdown protection through a generator-transformer group non-electric quantity protection cabinet.
[0027] The safe shutdown protection method 100 according to the embodiment of the present application can be applied to, for example, a 500 kV booster station. In the 500 kV booster station, a 3 / 2 wiring mode is widely used, which has high reliability and flexibility in the power system. For a generator-transformer unit (a combination of a generator and a transformer) using the 3 / 2 wiring mode, there are two parallel switches. Each parallel switch is provided with A, B, C three-phase standby normally closed contacts. For a 500 kV switch, a three-phase split structure is usually used. Usually, the parallel switch uses a circuit breaker as the main equipment, and in this type of circuit breaker, the three-phase normally closed contacts are usually installed inside the operating mechanism and are linked with the main contacts. When the main contacts act, the normally closed contacts are driven to act synchronously through mechanical transmission devices such as connecting rods and cams. For example, in the common spring operating mechanism, during the closing process, the main contacts are closed, and the mechanical structure connected thereto will cause the normally closed contacts that are originally closed to open; during the opening process, the main contacts are disconnected, and the normally closed contacts are closed. In this way, the state of the main contacts can be accurately reflected, and reliable information can be provided for the control, protection and signal circuit.
[0028] In order to ensure the reliability of the signal, the standby normally closed contacts of the A, B, C three-phase of the two parallel switches are taken, and a 3-to-2 logic mode is used, that is, only when at least two-phase normally closed contacts are closed, the system considers that the switch is in the open state. For example: if the standby normally closed contacts of A and B phases are closed, the system considers that the switch is in the open state. If the standby normally closed contacts of A, B and C phases are all closed, the system also considers that the switch is in the open state. If only the standby normally closed contact of A phase is closed, the system does not consider that the switch is in the open state. The open signal is transmitted to the protection execution module (non-electric quantity protection cabinet) through a cable. In the non-electric quantity protection cabinet, the open signals of the two parallel switches are subjected to "and" logic operation, and then are used as the tripping input of the protection, that is, the generator splitting signal. This means that only when the two parallel switches both send the open signal, the protection function hard board is in the situation of being put into operation, and the system performs the tripping operation, thereby ensuring the accuracy of the action and the stability of the system. The delay setting of the protection can help prevent misoperation caused by transient interference or signal fluctuation.
[0029] Through the above setting, the safe shutdown protection method 100 according to the embodiment of the application has the following advantages: 1) the signal acquisition reuses the original standby contact of the grid-connected switch, and the protection reuses the standby hard pressure plate of the non-electricity protection cabinet, without the need of adding new equipment, so that the entire power system has no redundant components in structure, and the cost is reduced. 2) the three-phase normally-closed contact and the "3-to-2 logic" structure of the signal acquisition can effectively determine the disconnection state of the switch, the hardware transmission can adapt to long-distance transmission, and the anti-interference capability is strong; the time delay relay can also effectively avoid signal jitter misoperation, so that the entire power system is more reliable in the effect of safe shutdown protection. 3) only hardware wiring modification is needed, without the need of modifying the program of the safety control device, the structural modification workload is small, and the implementation is easy.
[0030] In some embodiments, the signal transmission method further comprises connecting each execution element in steps one, two, three and four by a cable.
[0031] Through the setting, since the 500kV booster station is far away from the electronic room of the turbine generator protection cabinet at present, the required cable length is about four or five hundred meters, in order to improve the reliability, another intermediate relay can be added.
[0032] In some embodiments, the action voltage of the intermediate relay is set to 55%-70% of the rated DC voltage, and the action power is greater than or equal to 5W.
[0033] Through the setting, the provision of 15.7.8 in the "Eighteen Major Anti-accident Measures of State Grid Corporation of China (Revised Edition) and Preparing Instructions" can be met. The provision points out that all important circuits involving direct tripping should use intermediate relays with action voltage within 55%-70% of the rated DC voltage, and the action power should be not less than 5W.
[0034] In some embodiments, in the signal transmission step, the intermediate relay is installed at the cable terminal close to the non-electricity protection cabinet.
[0035] Through the setting, the signal transmission interference can be effectively reduced, the cable cost can be reduced, the maintenance convenience and the protection function fast response can be improved.
[0036] In some embodiments, the cable adopts a cable with a cross-sectional model of ZRC-KYJYP2-23-0.45 / 0.75, 4*2.5mm.
[0037] In the application, the connecting cable is preferably a copper core cross-linked polyethylene insulated C-class flame-retardant polyethylene sheathed copper wire braided shielding steel tape armored control cable. Through the setting, the connecting cable can adapt to long-distance transmission, and has strong anti-interference capability.
[0038] In some embodiments, in step four, the action delay Δt of the time delay relay is set to 50-100 ms.
[0039] In the present application, the purpose of setting the delay Δt is to improve the reliability of the protection action and avoid protection misoperation caused by signal interference or contact jitter. The action delay time Δt of the time delay relay is preferably 50 ms.
[0040] In some embodiments, the first level logic processing is realized by a relay combination circuit, when at least two phase normally closed contacts are turned on, the relay coil is electrified to output a switch opening signal.
[0041] In some embodiments, in step four, the backup protection hard panel is a mechanical hard panel and is connected in series between the generator splitting signal and the time delay relay.
[0042] In some embodiments, in the signal acquisition step, the A, B, and C three-phase backup normally closed contacts are copper conductive contacts.
[0043] Through this setting, the copper conductive contacts have better technical effects in terms of conductivity, physical properties, and stability.
[0044] Figures 2 to 4 The three-phase "3 out of 2" logic diagram, terminal diagram, and splitting signal terminal arrangement of one of the two grid-connected switches of the steam turbine generator power system according to the embodiments of the present application are shown respectively. According to the second aspect of the present application, a steam turbine generator power system applying the above safety shutdown protection method is provided, comprising: a signal acquisition module including two grid-connected switches, each of which is provided with A, B, and C three-phase backup normally closed contacts; a logic processing module connected with the signal acquisition module, the logic processing module including a first level logic unit and a second level logic unit, the first level logic unit being used for performing a three-out-of-two logic on the A, B, and C three-phase normally closed contact signals of a single grid-connected switch, and the second level logic unit being used for performing an AND logic on the opening signals of the two grid-connected switches; a protection execution module connected with the logic processing module, the protection execution module including a generator and transformer group non-electric quantity protection cabinet, the non-electric quantity protection cabinet being provided with a backup protection hard panel and a time delay relay; a hardware transmission component connected with the signal acquisition module, the logic processing module, and the protection execution module; wherein the first level logic unit is used for judging and outputting the opening signal of the grid-connected switch, the second level logic unit is used for judging and outputting the generator splitting signal, and the generator splitting signal is connected to the time delay relay through the backup protection hard panel.
[0045] In the above description of the application, unless otherwise explicitly specified and limited, the terms "fixed", "mounted", "connected" or "linked" and the like should be interpreted in a broad sense. For example, as to the term "connected", it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium, or it can be internal connection of two elements or interaction relationship between two elements. Therefore, unless otherwise explicitly specified in the application, the above terms can be understood in the specific meaning in the application by the person skilled in the art according to the specific circumstances.
[0046] According to the above description of the application, the person skilled in the art can also understand the terms used as follows, such as "upper", "lower", "front", "rear", "left", "right", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", "center", "longitudinal", "transverse", "clockwise" or "counterclockwise" and the like indicating the orientation or positional relationship terms are based on the orientation or positional relationship shown in the drawings of the application, which are only for the purpose of facilitating the description of the application and simplifying the description, and are not explicitly or implicitly indicating or suggesting that the devices or elements involved must have the specific orientation, be constructed and operated in a specific orientation, therefore the above orientation or positional relationship terms cannot be understood or interpreted as a limitation on the application scheme.
[0047] In addition, the terms "first" or "second" and the like used in the application to refer to the number or ordinal terms are only for the purpose of description, and cannot be understood as explicitly or implicitly indicating relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" or "second" can explicitly or implicitly include at least one of the features. In the description of the application, the meaning of "multiple" is at least two, such as two, three or more, etc., unless otherwise explicitly specified and limited.
[0048] Although the embodiments of the application have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided only by way of example. The person skilled in the art can think of many changes, modifications and alternatives without departing from the idea and spirit of the application. It should be understood that various alternatives to the embodiments of the application described herein can be employed in the practice of the application. The appended claims are intended to define the scope of protection of the application and therefore cover the equivalents or alternatives within the scope of the claims.
Claims
1. A method for safe shutdown protection of a turbogenerator after a split, characterized in that The method comprises the following steps: Step one, signal acquisition, further comprising: collecting signals through A, B, C three-phase standby normally closed contact points of two grid-connected switches, wherein the normally closed contact points are closed when the grid-connected switches are disconnected; Step two, first-level logic processing, further comprising: performing two-out-of-three logic judgment on the A, B, C three-phase normally closed contact point signals of a single grid-connected switch, and outputting the disconnection signal of the grid-connected switch when at least two normally closed contact points are turned on; Step three, second-level logic processing, further comprising: performing AND logic judgment on the disconnection signals of two grid-connected switches, and outputting a generator splitting signal; Step four, protection execution, further comprising: connecting the generator splitting signal to a delay relay through a standby protection hard panel, and executing safety shutdown protection through a generator-transformer group non-electric quantity protection cabinet.
2. The method of claim 1, wherein, The method further comprises signal transmission, which comprises: Connecting each execution element in the step one, the step two, the step three, and the step four by using a cable; Serially connecting an intermediate relay in the cable.
3. The method of claim 2, wherein, The action voltage of the intermediate relay is set to 55%-70% of the rated DC voltage, and the action power is greater than or equal to 5W.
4. The method of claim 2, wherein, In the signal transmission step, the intermediate relay is installed at the cable terminal close to the non-electric quantity protection cabinet.
5. The method of claim 2, wherein, The cable adopts a cable with a cross-sectional model of ZRC-KYJYP2-23-0.45 / 0.75, 4*2.5mm.
6. The method of claim 1-5, wherein, In the step four, the action delay of the delay relay is set to 50-100ms.
7. The method of claim 1-5, wherein, The first-level logic processing is realized by a relay combination circuit, and when at least two normally closed contact points are turned on, the relay coil is electrified to output the switch disconnection signal.
8. The method of claim 1-5, wherein, In the step four, the standby protection hard panel adopts a mechanical hard panel and is connected in series between the generator splitting signal and the delay relay.
9. The method of claim 1-5, wherein, In the signal acquisition step, the A, B, C three-phase standby normally closed contact points are copper conductive contact points.
10. A turbo-generator power system applying the safe shutdown protection method according to any one of claims 1-9, characterized in that, It comprises: A signal acquisition module comprising two grid-connected switches, each of which is provided with A, B, C three-phase standby normally closed contact points; A logic processing module connected with the signal acquisition module, the logic processing module comprising a first-level logic unit and a second-level logic unit, the first-level logic unit being used to perform two-out-of-three logic on the A, B, C three-phase normally closed contact point signals of a single grid-connected switch, and the second-level logic unit being used to perform AND logic on the disconnection signals of two grid-connected switches; A protection execution module connected with the logic processing module, the protection execution module comprising a generator-transformer group non-electric quantity protection cabinet, the non-electric quantity protection cabinet being provided with a standby protection hard panel and a delay relay; A hardware transmission assembly connected with the signal acquisition module, the logic processing module, and the protection execution module; The first-level logic unit is used to judge and output the disconnection signal of the grid-connected switch, the second-level logic unit is used to judge and output the generator splitting signal, and the generator splitting signal is connected to the delay relay through the standby protection hard panel.