Analysis method, electronic device and storage medium for the risk of turbine speeding caused by valve air leakage

Abstract

A method for analyzing the risk of turbine runaway caused by steam leakage of a turbine valve, an electronic device, and a storage medium, belonging to the technical field of turbine test methods. To solve the problem of effectively predicting the risk of turbine runaway caused by steam leakage of a turbine valve. The present invention collects the delay time T1 of the turbine valve, and calculates the steam energy E1 entering during the delay time T1 of the turbine valve; collects the closing time T2 of the turbine valve, and calculates the steam energy E2 entering during the closing time T2 of the turbine valve; calculates the expansion work E3 of the steam accumulated in all chambers of the turbine; calculates the rotor inertia energy E4 of the turbine; calculates the energy E5 generated by steam leakage of the turbine valve; calculates the maximum speed n of the turbine rotor max , and determines whether there is a risk of runaway. The present invention has a fast calculation speed, reliable analysis conclusions, avoids processes such as disassembling the valve, avoids delaying the startup of the power plant, and avoids economic losses of the power plant.

Description

Technical Field

[0001] The present invention belongs to the technical field of steam turbine test methods, and particularly relates to an analysis method, an electronic device and a storage medium for the risk of overspeed caused by steam leakage of a steam turbine valve. Background Art

[0002] At present, the steam turbine valve is detected through a tightness test. After the test, if the steam turbine valve does not leak, the machine can be started normally. If the steam turbine valve leaks, the tightness test of the steam turbine valve needs to be repeated. If it is still unqualified after multiple tests, starting the machine forcibly may cause the risk of overspeed during load rejection, resulting in very serious consequences. Therefore, if the valve tightness test is unqualified, it is solved by disassembling and reinstalling the valve, but the process of disassembling the valve will cause delays in starting the machine and cause significant economic losses. At present, there is no effective method to calculate and analyze whether the steam leakage of the steam turbine valve will cause the risk of overspeed. Summary of the Invention

[0003] The present invention aims to solve the problem of effectively predicting the risk of overspeed caused by steam leakage of a steam turbine valve, and proposes an analysis method, an electronic device and a storage medium for the risk of overspeed caused by steam leakage of a steam turbine valve.

[0004] To achieve the above object, the present invention is realized through the following technical solutions:

[0005] An analysis method for the risk of overspeed caused by steam leakage of a steam turbine valve, comprising the following steps:

[0006] S1. Collect the delay time T1 of the steam turbine valve, and calculate the inlet steam energy E1 of the delay time T1 of the steam turbine valve;

[0007] S2. Collect the closing time T2 of the steam turbine valve, and calculate the inlet steam energy E2 of the closing time T2 of the steam turbine valve;

[0008] S3. Calculate the expansion work E3 of the steam accumulated in all chambers of the steam turbine;

[0009] S4. Calculate the rotor inertia energy E4 of the steam turbine;

[0010] S5. Calculate the energy E5 generated by the steam leakage of the steam turbine valve;

[0011] S6. Based on the data obtained in steps S1 - S5, calculate the maximum speed n of the steam turbine rotor max , and the calculation formula is:

[0012]

[0013] where n0 is the designed speed of the steam turbine rotor, and when the obtained n maxWhen it is less than 1.08 times of n0, it is determined that there is no risk of runaway speed, and there is no need to replace the steam turbine valve; when the obtained n max is greater than or equal to 1.08 times of n0, it is determined that there is a risk of runaway speed, and the steam turbine valve needs to be replaced.

[0014] Furthermore, the calculation method of the inlet steam energy E1 of the delay time T1 of the steam turbine valve in step S1 is as follows:

[0015] S1.1. Search for the steam turbine design data: including the generator end power Ng, the steam turbine power No, and the steam turbine mechanical loss ΔN M , the steam turbine motor loss ΔNe, for later use;

[0016] S1.2. The calculation formula of E1 is:

[0017] E1 = (Ng + 0.8ΔNe) * T1 = (No - ΔN M - 0.2ΔNe) * T1.

[0018] Furthermore, the calculation method of the inlet steam energy E2 of the closing time T2 of the steam turbine valve in step S2 is as follows:

[0019] E2 = (Ng + 0.8ΔNe) * T2 = (No - ΔN M - 0.2ΔNe) * T2.

[0020] Furthermore, the calculation method of the expansion work E3 of the steam accumulated in all chambers of the steam turbine in step S3 is as follows:

[0021] S3.1. Calculate the initial internal energy E z(0) of the steam in the z-th chamber of the steam turbine, and the calculation formula is:

[0022]

[0023] where V z is the volume of the z-th chamber of the steam turbine, υ z(0) is the initial specific volume of the z-th chamber of the steam turbine, i z(0) is the initial enthalpy value of the z-th chamber of the steam turbine, and P z(0) is the initial pressure of the z-th chamber of the steam turbine;

[0024] S3.2. Calculate the final internal energy E z(e) of the adiabatic expansion of the steam in the z-th chamber of the steam turbine, and the calculation formula is:

[0025]

[0026] where υ z(e) is the final specific volume of the z-th chamber of the steam turbine, and i z(e)is the enthalpy value at the end of the z-th chamber of the steam turbine, P z(e) is the end pressure of the z-th chamber of the steam turbine;

[0027] S3.3. Calculate the energy difference ΔE caused by the mass change in the z-th chamber of the steam turbine z , and the calculation formula is:

[0028]

[0029] S3.4. Calculate the expansion work E3 of the accumulated steam in all chambers of the steam turbine. The calculation formula is:

[0030]

[0031] Among them, the number of all chambers of the steam turbine is n, z is any one of n, η is the efficiency, and the value of η is 0.8.

[0032] Furthermore, the calculation formula for the rotational inertia energy E4 of the rotor of the steam turbine in step S4 is:

[0033]

[0034] Among them, I is the rotational inertia of the steam turbine rotor, and ω0 is the initial angular acceleration of the steam turbine rotor.

[0035] Furthermore, the calculation formula for the energy E5 generated by the leakage of the steam turbine valve in step S5 is:

[0036] E5 = Δh * Q i *5

[0037] Among them, Δh is the enthalpy drop value of the steam turbine, and Q i is the steam turbine valve leakage volume, and Q i is obtained through the flow measurement point.

[0038] Furthermore, the designed rotational speed n0 of the steam turbine rotor in step S6 is 3000 rpm.

[0039] An electronic device, including a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the steps of the method for analyzing the risk of runaway caused by the leakage of the steam turbine valve are implemented.

[0040] A computer-readable storage medium, on which a computer program is stored, characterized in that when the computer program is executed by a processor, the method for analyzing the risk of runaway caused by the leakage of the steam turbine valve is implemented.

[0041] Advantages of the present invention:

[0042] An analysis method for the risk of turbine overspeed caused by leakage of steam turbine valves. After the steam turbine trips off load, the overspeed protection should not operate, and the overspeed speed of the steam turbine under full load should not exceed 8% of the working speed. This method has a fast calculation speed, reliable analysis conclusions, avoids procedures such as valve disassembly, delays in power plant startup, and economic losses of the power plant, and ensures the safety of the power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 FIG. is a schematic diagram of air leakage of the high-pressure control valve of a steam turbine valve according to the present invention;

[0044] Figure 2 FIG. is a schematic diagram of air leakage of the intermediate-pressure control valve of a steam turbine valve according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0045] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the specific embodiments described are only a part of the embodiments of the present invention, rather than all of the specific embodiments. The components of the specific embodiments of the present invention usually described and shown in the accompanying drawings herein can be arranged and designed in various different configurations, and the present invention can also have other embodiments.

[0046] Therefore, the detailed description of the specific embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents the selected specific embodiments of the present invention. All other specific embodiments obtained by those skilled in the art based on the specific embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0047] To further understand the content, features and effects of the present invention, the following specific embodiments are exemplified and combined with the attached Figure 1 and attached Figure 2 The details are as follows: Specific Embodiment 1:

[0049] An analysis method for the risk of turbine overspeed caused by leakage of steam turbine valves, comprising the following steps:

[0050] S1. Collect the delay time T1 of the steam turbine valve and calculate the inlet steam energy E1 of the delay time T1 of the steam turbine valve;

[0051] Further, the calculation method of the inlet steam energy E1 of the delay time T1 of the steam turbine valve in step S1 is:

[0052] S1.1. Search for the steam turbine design data: including the generator end power Ng, the steam turbine power No, and the steam turbine mechanical loss ΔN M , and the steam turbine motor loss ΔNe, for later use;

[0053] S1.2. The calculation formula for E1 is:

[0054] E1 = (Ng + 0.8ΔNe) * T1 = (No - ΔN M - 0.2ΔNe) * T1;

[0055] S2. Collect the closing time T2 of the steam turbine valve, and calculate the steam energy E2 entering at the closing time T2 of the steam turbine valve;

[0056] Furthermore, the calculation method for the steam energy E2 entering at the closing time T2 of the steam turbine valve in step S2 is:

[0057] E2 = (Ng + 0.8ΔNe) * T2 = (No - ΔN M - 0.2ΔNe) * T2;

[0058] S3. Calculate the expansion work E3 of the steam accumulated in all chambers of the steam turbine;

[0059] Furthermore, the calculation method for the expansion work E3 of the steam accumulated in all chambers of the steam turbine in step S3 is:

[0060] S3.1. Calculate the initial internal energy E z(0) of the steam in the z-th chamber of the steam turbine, and the calculation formula is:

[0061]

[0062] where V z is the volume of the z-th chamber of the steam turbine, υ z(0) is the initial specific volume of the steam in the z-th chamber of the steam turbine, i z(0) is the initial enthalpy value of the steam in the z-th chamber of the steam turbine, P z(0) is the initial pressure of the steam in the z-th chamber of the steam turbine;

[0063] S3.2. Calculate the final internal energy E z(e) of the steam in the z-th chamber of the steam turbine during adiabatic expansion, and the calculation formula is:

[0064]

[0065] where υ z(e) is the final specific volume of the steam in the z-th chamber of the steam turbine, i z(e) is the final enthalpy value of the steam in the z-th chamber of the steam turbine, P z(e) is the final pressure of the steam in the z-th chamber of the steam turbine;

[0066] S3.3. Calculate the energy difference ΔE caused by the mass change in the z-th chamber of the steam turbine z , and the calculation formula is:

[0067]

[0068] S3.4. Calculate the expansion work E3 of the accumulated steam in all chambers of the steam turbine, and the calculation formula is:

[0069]

[0070] Among them, the number of all chambers of the steam turbine is n, z is any one of n, η is the efficiency, and η is set to 0.8;

[0071] S4. Calculate the rotor inertia energy E4 of the steam turbine;

[0072] Furthermore, the calculation formula for the rotor inertia energy E4 of the steam turbine in step S4 is:

[0073]

[0074] Among them, I is the moment of inertia of the steam turbine rotor, and ω0 is the initial angular acceleration of the steam turbine rotor;

[0075] S5. Calculate the energy E5 generated by the leakage of the steam turbine valve;

[0076] Furthermore, the calculation formula for the energy E5 generated by the leakage of the steam turbine valve in step S5 is:

[0077] E5 = Δh * Q i *5

[0078] Among them, Δh is the enthalpy drop value of the steam turbine, and Q i is the steam leakage volume of the steam turbine valve, and Q i is obtained through the flow measurement point;

[0079] S6. Based on the data obtained in steps S1 - S5, calculate the maximum speed n of the steam turbine rotor max , and the calculation formula is:

[0080]

[0081] Among them, n0 is the designed speed of the steam turbine rotor. When the obtained n max is less than 1.08 times of n0, it is judged that there is no risk of overspeed, and there is no need to replace the steam turbine valve; when the obtained n max is greater than or equal to 1.08 times of n0, it is judged that there is a risk of overspeed, and the steam turbine valve needs to be replaced;

[0082] Furthermore, the designed rotational speed n0 of the steam turbine rotor in step S6 is taken as 3000 rpm.

[0083] The above method is experimentally verified, and the experimental background is as follows:

[0084] The steam turbine valve tightness tests were successively carried out on Unit 1 and Unit 2 of a certain power plant. The throttle valve tightness test of Unit 1 was carried out on September 3, 2022. The rotational speed dropped to 810 rpm and then stopped dropping, and the throttle valve tightness was unqualified. After grinding, the throttle valve tightness test was carried out again on September 29, 2022. The rotational speed dropped to 810 rpm and then stopped dropping, and the throttle valve tightness was unqualified. When the steam turbine valve of Unit 1 was in the fully closed state of the throttle valve, the steam leakage form was as Figure 1 shown. The leakage position was measured by the dimensions at the time of factory as the position shown in Figure 1 . The hole size was 142.35 mm with a tolerance of +0.025 / 0, and the shaft size was 142 mm with a tolerance of 0 / -0.025. The maximum annular steam leakage area of a single high-pressure throttle valve was calculated as 89.333 mm 2 , and the minimum annular steam leakage area was 78.165 mm 2 . There were 4 high-pressure throttle valves in total.

[0085] The throttle valve tightness test of Unit 2 was carried out on September 11, 2022. The rotational speed dropped to 938 rpm and then stopped dropping, and the throttle valve tightness was unqualified. When the steam turbine valve of Unit 2 was in the fully closed state of the throttle valve, the steam leakage form was as Figure 2 shown. The leakage position was measured as the position shown in Figure 2 . The hole size was 132.2 mm with a tolerance of 0 / -0.03, and the shaft size was 131.72 mm with a tolerance of 0 / -0.03. The maximum annular steam leakage area of a single medium-pressure throttle valve was calculated as 105.7 mm 2 , and the minimum annular steam leakage area was 93.27 mm 2 . There were 2 medium-pressure throttle valves in total.

[0086] Then, the steam leakage amount and leakage area of the valve were calculated, and the specific values are shown in the following table:

[0087] Table 1 Valve calculation data

[0088]

[0089] In the case of the valve tightness test, the energy of the steam leakage from the regulating valve will cause an increase in the energy of the steam turbine system. According to the law of conservation of energy, when the rotor speed is stable and unchanged during the test, the energy released by the steam due to enthalpy drop is balanced with the energy lost by the shafting during rotation. For the energy loss of the rotor, it mainly comes from the support bearing loss, thrust bearing loss, main oil pump energy loss, windage energy loss and motor energy loss. Each energy loss is a function related to the speed, and the following conclusion is calculated: Calculated according to the maximum tolerance air leakage volume on the drawing, the highest theoretical calculated speed of the rotor during stability in the tightness test is 397 rpm.

[0090] For the load rejection and speed rise process of the steam turbine unit, it is considered that after the unit valves are closed, the generator no longer generates electric energy, the resistance of the unit decreases, and the energy of the remaining gas in the cylinder does work on the rotor, resulting in a speed increase process.

[0091] After load rejection, the load of the unit decreases instantaneously. At the moment of load rejection, the steam still exists inside the unit, and the steam energy remains unchanged instantaneously. Therefore, the increased kinetic energy during the speed rise process should be equal to the energy of the remaining steam in the cylinder at shutdown. According to the above method, it can be calculated that the maximum theoretical speed rise during 100% load rejection without air leakage is 3122 rpm.

[0092] For the case where there is air leakage in the valve, it is equivalent to adding an external energy input source. Since the time of the speed rise process is short, the difference between the air leakage volume of the valve and the remaining gas volume in the cylinder is large during the speed rise, and the energy generated by the valve air leakage during the speed rise process is small. According to the above method, the maximum theoretical speed rise of the unit during 100% load rejection can be calculated as 3125 rpm.

[0093] By comparison, it can be seen that the difference in the speed rise of the rotor is very small whether there is air leakage in the valve or not. Therefore, it can be considered that under the maximum tolerance air leakage volume in theory, the air leakage of the valve has no obvious influence on the load rejection test of the unit and is less than 1.08n0. It can be concluded that the air leakage of the valve has no obvious influence on the maximum speed of the speed rise test and can operate normally without shutdown for maintenance. Specific implementation method two:

[0095] The computer device of the present invention can be a device including a processor and a memory, such as a single-chip microcomputer including a central processing unit. And, when the processor is used to execute the computer program stored in the memory, it realizes the steps of the above-mentioned recommendation method for modifiable relation-driven recommendation data based on CREO software.

[0096] The so-called processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0097] The memory may mainly include a program storage area and a data storage area. Among them, the program storage area may store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area may store data created according to the use of the mobile phone (such as audio data, phone book, etc.). In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, memory, plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, at least one magnetic disk storage device, flash memory device, or other volatile solid-state storage devices. Specific Embodiment Three:

[0099] The computer-readable storage medium of the present invention can be any form of storage medium readable by the processor of a computer device, including but not limited to non-volatile memory, volatile memory, ferroelectric memory, etc. A computer program is stored on the computer-readable storage medium. When the processor of the computer device reads and executes the computer program stored in the memory, the steps of the above-mentioned modeling method for modifying relationship-driven modeling data based on CREO software can be implemented. The computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0100] It should be noted that relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0101] Although the present application has been described above with reference to specific embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the various features in the specific embodiments disclosed in the present application can be combined with each other in any way. The exhaustive description of these combinations is not given in this specification only for the sake of saving space and resources. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for analyzing the risk of turbine runaway caused by valve air leakage, characterized in that, It includes the following steps: S1. Collect the delay time T1 of the steam turbine valve, and calculate the inlet steam energy E1 of the delay time T1 of the steam turbine valve; S2. Collect the closing time T2 of the steam turbine valve, and calculate the inlet steam energy E2 of the closing time T2 of the steam turbine valve; S3. Calculate the expansion work E3 of the accumulated steam in all chambers of the steam turbine; S4. Calculate the rotor inertia energy E4 of the steam turbine; S5. Calculate the energy E5 generated by the leakage of the steam turbine valve; S6. Calculate the maximum rotational speed n of the steam turbine rotor based on the data obtained in steps S1 - S5 max , and the calculation formula is as follows: Among them, n0 is the designed rotational speed of the steam turbine rotor. When the obtained n max is less than 1.08 times of n0, it is judged that there is no runaway risk and there is no need to replace the steam turbine valve; when the obtained n max is greater than or equal to 1.08 times of n0, it is judged that there is a runaway risk and the steam turbine valve needs to be replaced.

2. The method for analyzing the risk of turbine runaway caused by valve air leakage according to claim 1, characterized in that, The calculation method of the inlet steam energy E1 of the delay time T1 of the steam turbine valve in step S1 is: S1.

1. Search for steam turbine design data: including the generator end power Ng, the steam turbine power No, and the steam turbine mechanical loss ΔN M , the steam turbine motor loss ΔNe, to be used later; S1.

2. The calculation formula of E1 is: E1 = (Ng + 0.8ΔNe) * T1 = (No - ΔN M - 0.2ΔNe) * T1.

3. The method for analyzing the risk of turbine runaway caused by valve air leakage according to claim 2, characterized in that, The calculation method of the inlet steam energy E2 of the closing time T2 of the steam turbine valve in step S2 is: E2 = (Ng + 0.8ΔNe) * T2 = (No - ΔN M - 0.2ΔNe) * T2.

4. The method for analyzing the risk of turbine runaway caused by valve air leakage according to claim 3, characterized in that, The calculation method of the expansion work E3 of the accumulated steam in all chambers of the steam turbine in step S3 is: S3.

1. Calculate the initial internal energy E of the steam in the z-th chamber of the steam turbine z(0) , and the calculation formula is as follows: Among them, V z is the volume of the z-th chamber of the steam turbine, υ z(0) is the initial specific volume of the z-th chamber of the steam turbine, i z(0) is the initial enthalpy value of the z-th chamber of the steam turbine, P z(0) is the initial pressure of the z-th chamber of the steam turbine; S3.

2. Calculate the final internal energy E of the steam in the z-th chamber of the steam turbine during adiabatic expansion. z(e) , and the calculation formula is as follows: where υ z(e) is the specific volume at the end of the z-th chamber of the steam turbine, i z(e) is the enthalpy value at the end of the z-th chamber of the steam turbine, P z(e) is the end pressure of the z-th chamber of the steam turbine; S3.

3. Calculate the energy difference ΔE caused by the mass change in the z-th chamber of the steam turbine z , and the calculation formula is as follows: S3.

4. Calculate the expansion work E3 of the accumulated steam in all chambers of the steam turbine, and the calculation formula is: Among them, the number of all chambers of the steam turbine is n, z is any one of n, η is the efficiency, and η is set to take the value of 0.

8.

5. The method for analyzing the risk of turbine runaway caused by valve air leakage according to claim 4, characterized in that, The calculation formula of the rotor inertia energy E4 of the steam turbine in step S4 is: Among them, I is the moment of inertia of the steam turbine rotor, and ω0 is the initial angular acceleration of the steam turbine rotor.

6. A method for analyzing the risk of turbine overspeed caused by valve air leakage according to claim 5, characterized in that, The calculation formula of the energy E5 generated by the leakage of the steam turbine valve in step S5 is: E5 = Δh * Q i *5 Among them, Δh is the enthalpy drop value of the steam turbine, and Q i is the steam leakage of the steam turbine valve, and Q i is obtained through the flow measurement point.

7. A method for analyzing the risk of turbine overspeed caused by valve air leakage according to claim 6, characterized in that, In step S6, the designed rotational speed n0 of the steam turbine rotor takes the value of 3000 rpm.

8. An electronic device, characterized in that, It includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, it realizes the steps of an analysis method for the risk of runaway caused by the leakage of a steam turbine valve according to any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it realizes an analysis method for the risk of runaway caused by the leakage of a steam turbine valve according to any one of claims 1-7.

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