Test system and calculation method for leakage rate of intermediate shaft seal in high and medium pressure cylinder

Abstract

The application provides a high-pressure cylinder intermediate shaft seal steam leakage rate testing system and a calculation method. The method comprises the following steps: obtaining first operating parameters in the high-pressure cylinder intermediate shaft seal steam leakage rate testing system when a leakage testing valve is in a fully open state under a rated working condition; calculating steam flow through the leakage testing valve according to the first operating parameters; when the steam flow meets a first preset condition, obtaining second operating parameters corresponding to the high-pressure cylinder intermediate shaft seal steam leakage rate testing system when the leakage testing valve is in a fully open or fully closed state under different preset working conditions, and calculating a high-pressure cylinder intermediate shaft seal steam leakage rate according to the second operating parameters. The application can solve the problem that the steam leakage state of the high-pressure cylinder intermediate shaft in a steam turbine cannot be accurately monitored efficiently in the prior art, and provides accurate reference data for the overhaul of the steam turbine.

Description

Technical Field

[0001] This invention relates to the field of steam turbine thermodynamic performance testing technology, and in particular to a test system and calculation method for the leakage rate of intermediate shaft seals in high-pressure and intermediate-pressure cylinders. Background Technology

[0002] The amount of steam leakage from the steam turbine's steam seals directly affects the turbine's normal operating capacity and performance. Among the operating parameters of the inter-cylinder shaft seals in power plant steam turbines, the leakage flow rate of the inter-cylinder shaft seals most directly reflects the working condition of the seals. Under the same operating boundary conditions, the lower the steam leakage in the leakage channel of the intermediate shaft seal in the high-pressure and intermediate-pressure cylinders of the steam turbine, the better the operating condition of the inter-cylinder shaft seals.

[0003] Currently, the amount of steam leakage from the intermediate shaft seal leakage channel of the high-pressure and intermediate-pressure cylinder in power plants cannot be directly measured. When using test methods such as variable steam temperature to determine the steam leakage rate of the intermediate shaft seal leakage channel of the high-pressure and intermediate-pressure cylinder, the workload of on-site test adjustments is too large, resulting in the inability to efficiently and accurately monitor the steam leakage status of the intermediate shaft seal leakage channel of the high-pressure and intermediate-pressure cylinder of the turbine. Summary of the Invention

[0004] This invention provides a system and calculation method for testing the leakage rate of intermediate shaft seals in high-pressure and intermediate-pressure cylinders, in order to solve the problem in the prior art that it is impossible to efficiently and accurately monitor the leakage status of shaft seals in the leakage channels of intermediate shaft seals in high-pressure and intermediate-pressure cylinders of steam turbines.

[0005] In a first aspect, embodiments of the present invention provide a steam leakage rate testing system for intermediate shaft seals of high-pressure cylinders, comprising: a leakage branch pipeline, a leakage test valve, and a condenser;

[0006] The steam inlet of the leakage branch pipe is connected to the intermediate shaft seal leakage channel of the high-pressure cylinder, and the steam outlet of the leakage branch pipe is connected to the condenser; n-stage shaft seals are arranged on the intermediate shaft seal leakage channel of the high-pressure cylinder, and the leakage branch pipe to the condenser is connected to the m-stage shaft seal along the direction of leakage steam flow, where n and m are positive integers, and m is less than n;

[0007] The leakage test valve is installed on the leakage branch pipeline.

[0008] Secondly, embodiments of the present invention provide a method for calculating the leakage rate of intermediate shaft seals in high-pressure cylinders, employing the high-pressure cylinder intermediate shaft seal leakage rate testing system described in the first aspect or any possible implementation thereof. The method for calculating the leakage rate of intermediate shaft seals in high-pressure cylinders includes:

[0009] Obtain the first operating parameters of the intermediate shaft seal leakage rate test system of the high-pressure cylinder when the leakage test valve is fully open under rated operating conditions;

[0010] Calculate the steam flow rate through the leakage test valve based on the first operating parameters;

[0011] When the steam flow rate meets the first preset condition, the second operating parameters corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder are obtained under different preset operating conditions when the leakage test valve is in the fully open or fully closed state, and the intermediate shaft seal leakage rate of the high-pressure cylinder is calculated based on the second operating parameters.

[0012] In one possible implementation,

[0013] The first operating parameter includes: the critical pressure drop ratio x of the leakage test valve. T Valve flow coefficient K v When the leakage test valve is fully open under rated operating conditions, the steam pressure P after the high-pressure cylinder regulating stage is... csd and steam temperature t csd Steam pressure P before the inlet valve of the intermediate pressure cylinder IPin1d The design pressure loss PS of the steam inlet valve of the intermediate pressure cylinder;

[0014] The step of calculating the steam flow rate through the leakage test valve based on the first operating parameters includes:

[0015] according to Calculate the inlet steam pressure of the intermediate pressure cylinder when the leakage test valve is fully open under rated operating conditions;

[0016] according to Calculate the steam pressure at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions;

[0017] According to t vind =tph[P vind ,hpt(P csd ,t csd )] Calculate the steam temperature at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions;

[0018] according to Calculate the steam flow rate through the leakage test valve;

[0019] Among them, W d P represents the steam flow rate through the leakage test valve. IPin3d P represents the inlet steam pressure of the intermediate pressure cylinder when the leakage test valve is fully open under rated operating conditions. vindThis indicates the steam pressure and temperature at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions. 'n' represents the total number of shaft seal stages installed on the intermediate shaft seal leakage passage of the high-pressure cylinder. 'm' represents the number of shaft seal stages (counted along the direction of shaft seal leakage steam flow) upstream of the location where the leakage branch pipeline connects to the intermediate shaft seal leakage passage of the high-pressure cylinder. 't' represents the steam pressure and temperature at the inlet of the leakage branch pipeline. vind This represents the steam temperature at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions. hpt(P,t) is the steam-water characteristic function for calculating the enthalpy of the medium based on the medium pressure and temperature. tph(P,h) is the steam-water characteristic function for calculating the enthalpy of the medium based on the medium pressure and enthalpy. Cppt(P,t) represents the steam-water characteristic function for calculating the isobaric specific heat of the medium based on the medium pressure and temperature. Cvpt(P,t) represents the steam-water characteristic function for calculating the isovolic specific heat of the medium based on the medium pressure and temperature. vpt(P,t) represents the steam-water characteristic function for calculating the specific volume of the medium based on the medium pressure and temperature.

[0020] In one possible implementation, determining that the steam flow rate satisfies a first preset condition includes:

[0021] When the steam flow rate is greater than a preset multiple of the design leakage flow rate of the intermediate shaft seal of the high-pressure cylinder, it is determined that the steam flow rate meets the first preset condition.

[0022] It also includes: when the steam flow rate does not meet the first preset condition, replacing the leakage test valve and jumping to the step of "obtaining the first operating parameters of the intermediate shaft seal leakage rate test system of the high-pressure cylinder under rated operating conditions when the leakage test valve is in the fully open state" and subsequent steps until the steam flow rate meets the first preset condition.

[0023] In one possible implementation, the second operating parameter includes a third operating parameter, a fourth operating parameter, and a fifth operating parameter;

[0024] The process of obtaining the second operating parameters corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder under different preset operating conditions, when the leakage test valve is in the fully open or fully closed state, and calculating the intermediate shaft seal leakage rate of the high-pressure cylinder based on the second operating parameters, includes:

[0025] When the leakage test valve is fully open, the third operating parameter corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder under the current first preset operating condition and the fourth operating parameter corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder under the current second preset operating condition are obtained. The rated load of the unit under the first preset operating condition and the second preset operating condition differs by more than 15% of the rated load.

[0026] Based on the third operating parameter, calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is in the fully open state under the current first preset operating condition;

[0027] Based on the fourth operating parameter, calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully open under the current second preset operating condition;

[0028] When the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully open under the current first preset operating condition and the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully open under the current second preset operating condition meet the second preset condition, the fifth operating parameter corresponding to the leakage rate test system of the intermediate shaft seal of the high and medium pressure cylinder when the leakage test valve is fully closed under the current second preset operating condition is obtained.

[0029] Calculate the steam leakage rate of the intermediate shaft seal of the high-pressure cylinder based on the fifth operating parameter.

[0030] One possible implementation also includes:

[0031] When the intermediate-pressure cylinder flow efficiency under the current first preset operating condition with the leakage test valve fully open and the intermediate-pressure cylinder flow efficiency under the current second preset operating condition with the leakage test valve fully open do not meet the second preset condition, the rated load of the unit under the first preset operating condition and the second preset operating condition is reduced to obtain a new first preset operating condition and a new second preset operating condition. Then, the process jumps to the step of "obtaining the third operating parameter corresponding to the intermediate shaft seal leakage rate test system of the intermediate-pressure cylinder under the current first preset operating condition and the fourth operating parameter corresponding to the intermediate-pressure cylinder leakage rate test system under the current second preset condition" and subsequent steps until the intermediate-pressure cylinder flow efficiency under the current first preset operating condition with the leakage test valve fully open and the intermediate-pressure cylinder flow efficiency under the current second preset operating condition meet the second preset condition.

[0032] In one possible implementation, calculating the steam leakage rate of the intermediate shaft seal of the high-pressure cylinder based on the fifth operating parameter includes:

[0033] The intermediate shaft seal leakage rate of the high-pressure cylinder is assigned the preset shaft seal leakage rate.

[0034] Based on the fifth operating parameter and the current preset shaft seal leakage rate, calculate the medium-pressure cylinder flow efficiency when the leakage test valve is in the fully closed state under the second preset operating condition;

[0035] When the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully open under the second preset operating condition and the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition meet the third preset condition, the preset shaft seal leakage rate is determined to be the intermediate shaft seal leakage rate of the intermediate high-pressure cylinder.

[0036] In one possible implementation, calculating the intermediate-pressure cylinder flow efficiency under the second preset operating condition when the leakage test valve is fully closed, based on the fifth operating parameter and the current preset shaft seal leakage rate, includes:

[0037] Based on the fifth operating parameter and the current preset shaft seal leakage rate, calculate the enthalpy value of the intermediate pressure cylinder inlet steam when the leakage test valve is in the fully closed state under the second preset operating condition;

[0038] Based on the inlet steam enthalpy value and the steam pressure before the inlet steam valve of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition, calculate the inlet steam temperature of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition.

[0039] Based on the enthalpy of the inlet steam before the inlet steam valve of the intermediate pressure cylinder, the inlet steam temperature of the intermediate pressure cylinder, and the fifth operating parameter when the leakage test valve is in the fully closed state under the second preset operating condition, the flow efficiency of the intermediate pressure cylinder when the leakage test valve is in the fully closed state is calculated.

[0040] One possible implementation also includes:

[0041] When the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the second preset operating condition and the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully closed under the second preset operating condition do not meet the third preset condition, the intermediate shaft seal leakage rate of the high-pressure cylinder is assigned a new preset shaft seal leakage rate, and calculations are performed based on the fifth operating parameter and the current preset shaft seal leakage rate until the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the second preset operating condition and the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully closed under the second preset operating condition meet the third preset condition, and the new shaft seal leakage rate is determined to be the intermediate shaft seal leakage rate of the high-pressure cylinder.

[0042] In one possible implementation, the fifth operating parameter includes: the steam pressure P after the high-pressure cylinder regulating stage when the leakage test valve is fully closed under the second preset operating condition. cst VC and steam temperature t cst VC Steam pressure P before the inlet valve of the intermediate pressure cylinder IPin1d VC and steam temperature t IPin1d VCSteam pressure P in the medium-pressure cylinder outlet low-pressure connecting pipeline IPexhd VC and steam temperature t IPexht VC ;

[0043] The step of calculating the enthalpy of the intermediate-pressure cylinder inlet steam when the leakage test valve is fully closed under the second preset operating condition, based on the fifth operating parameter and the current preset shaft seal leakage rate, includes:

[0044] according to Calculate the enthalpy of the steam entering the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition;

[0045] Among them, h IPin3d VC R represents the enthalpy of the steam entering the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition. l Indicates the preset shaft seal leakage rate;

[0046] Based on the inlet steam enthalpy and the steam pressure before the intermediate pressure cylinder inlet valve when the leakage test valve is fully closed under the second preset operating condition, the intermediate pressure cylinder inlet steam temperature when the leakage test valve is fully closed under the second preset operating condition is calculated, including:

[0047] according to Calculate the inlet steam temperature of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition;

[0048] Among them, P IPin3d VC This represents the inlet steam pressure of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition, t. IPin3t VC This indicates the inlet steam temperature of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition;

[0049] Based on the enthalpy of the inlet steam before the inlet steam valve of the intermediate pressure cylinder, the inlet steam temperature of the intermediate pressure cylinder, and the fifth operating parameter when the leakage test valve is fully closed under the second preset operating condition, the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition is calculated, including:

[0050] according to Calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully closed under the second preset working condition;

[0051] Where, η IP VCThe flow efficiency of the medium-pressure cylinder is indicated when the leakage test valve is fully closed under the second preset working condition. spt(P,t) represents the steam-water characteristic function that solves for the entropy of the medium based on the medium pressure and temperature. hps(P,s) represents the steam-water characteristic function that solves for the enthalpy of the medium based on the medium pressure and entropy.

[0052] This invention provides a system and method for testing and calculating the leakage rate of intermediate shaft seals in high-pressure and intermediate-pressure cylinders. By adding a leakage branch pipeline to the leakage channel of the intermediate shaft seal in the high-pressure and intermediate-pressure cylinder and installing a leakage test valve on the leakage branch pipeline, the system operating parameters are obtained under different load conditions with the leakage test valve fully open and fully closed. Based on the operating parameters, the leakage rate of the intermediate shaft seal in the high-pressure and intermediate-pressure cylinder can be calculated. This solves the problem in the prior art of not being able to efficiently and accurately monitor the leakage status of the intermediate shaft seal in the high-pressure and intermediate-pressure cylinder of a steam turbine, and provides accurate reference data for the maintenance of the steam turbine itself. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a schematic diagram of the intermediate shaft seal leakage rate testing system for high and medium pressure cylinders provided in this embodiment of the invention;

[0055] Figure 2 This is a flowchart illustrating the implementation of the method for calculating the steam leakage rate of the intermediate shaft seal in a high-pressure cylinder provided in this embodiment of the invention.

[0056] Figure 3 This is a flowchart illustrating the implementation of a method for calculating the steam leakage rate of intermediate shaft seals in high-pressure cylinders, provided in another embodiment of the present invention.

[0057] Figure 4 This is a flowchart illustrating the implementation of calculating shaft seal leakage rate according to an embodiment of the present invention. Detailed Implementation

[0058] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0059] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0060] Figure 1 A schematic diagram of the intermediate shaft seal leakage rate testing system for high and medium pressure cylinders provided in an embodiment of the present invention includes: a leakage branch pipeline 1, a leakage test valve 2, and a condenser 3;

[0061] The steam inlet of the leakage branch pipe 1 is connected to the intermediate shaft seal leakage channel 4 of the high-pressure cylinder, and the steam outlet of the leakage branch pipe 1 is connected to the condenser 3. The intermediate shaft seal leakage channel 4 of the high-pressure cylinder is provided with n-stage shaft seals. The leakage branch pipe 1 to the condenser 3 is connected to the m-stage shaft seal along the direction of leakage steam flow, where n and m are positive integers, and m is less than n.

[0062] Leakage test valve 2 is installed on leakage branch pipeline 1.

[0063] The intermediate shaft seal leakage rate test system for high and medium pressure cylinders also includes: high pressure cylinder pressure stage 5, high pressure cylinder regulating stage 6, boiler superheater 7, intermediate pressure cylinder 8, boiler reheater 9, and steam inlet valve 10.

[0064] The steam inlet of the high-pressure cylinder pressure stage 5 is connected to the outlet of the high-pressure cylinder regulating stage 6, and the steam inlet of the high-pressure cylinder regulating stage 6 is connected to the steam outlet of the boiler superheater 7 through a pipeline.

[0065] The steam inlet of the intermediate pressure cylinder 8 is connected to the steam outlet of the boiler reheater 9 through a pipeline; the steam inlet valve 10 is installed on the pipeline between the intermediate pressure cylinder 8 and the boiler reheater 9 to regulate the steam entering the intermediate pressure cylinder 8.

[0066] The high-pressure steam inlet of the intermediate shaft seal leakage passage 4 of the high-pressure cylinder is connected to the outlet of the high-pressure cylinder regulating stage 6, and the steam outlet is connected to the inlet valve 10 and the steam inlet of the intermediate-pressure cylinder 8.

[0067] See Figure 1 The direction of the arrow indicates the direction of steam flow. Figure 1 In the middle, the steam outlet of the high-pressure cylinder 5 is connected to the reheater, and the steam outlet of the intermediate-pressure cylinder 8 is also connected to the low-pressure connecting pipe 11 at the outlet of the intermediate-pressure cylinder.

[0068] Steam turbines are equipped with high-pressure, intermediate-pressure, and low-pressure cylinders based on their operating characteristics. The high-pressure cylinder is the initial stage where the main steam enters the turbine; at this point, the steam pressure and temperature are high, so the blades are short and the impeller diameter is large. The intermediate-pressure cylinder is the second cylinder in the turbine to receive steam, and it is usually designed with a medium diameter. The steam pressure in this cylinder is lower than that in the high-pressure cylinder, and higher than that in the low-pressure cylinder. The high-pressure, intermediate-pressure, and low-pressure cylinders are arranged side-by-side, differing only in their internal pressure.

[0069] Steam turbine stages can be divided into regulating stages and non-regulating stages. The regulating stage refers to the first power stage of the steam turbine, whose flow area can change with load variations due to the partial intake of steam, thus achieving a regulating effect. Non-regulating stages can also be called pressure stages; all steam turbine stages except the regulating stage are pressure stages.

[0070] The aforementioned intermediate shaft seal leakage rate testing system for high-pressure and intermediate-pressure cylinders adds a leakage branch pipeline to the intermediate shaft seal leakage channel between the high-pressure and intermediate-pressure cylinders, and installs a leakage test valve on the leakage branch pipeline. During operation, by acquiring the operating data of the leakage test valve in both fully open and fully closed states, the shaft seal leakage rate of the intermediate shaft seal leakage channel of the high-pressure and intermediate-pressure cylinders can be calculated conveniently and quickly. This solves the problem in existing technologies that cannot efficiently and accurately monitor the shaft seal leakage status of the intermediate shaft seal leakage channel of the high-pressure and intermediate-pressure cylinders of steam turbines, and provides accurate reference data for the maintenance of the steam turbine itself.

[0071] Figure 2 This is a flowchart illustrating the implementation of the method for calculating the steam leakage rate of the intermediate shaft seal in a high-pressure cylinder according to an embodiment of the present invention. Figure 1 The steam leakage rate test system for intermediate shaft seals in high-pressure and intermediate-pressure cylinders, as shown, and the calculation method for the steam leakage rate of intermediate shaft seals in high-pressure and intermediate-pressure cylinders are detailed below:

[0072] Step 201: Obtain the first operating parameters of the intermediate shaft seal leakage rate test system of the high-pressure cylinder under rated operating conditions, when the leakage test valve is in the fully open state.

[0073] The aforementioned intermediate shaft seal leakage rate test system for high-pressure cylinders is equipped with a leakage test valve. The size of the leakage test valve varies, and the steam flow rate through the leakage test valve also varies. Therefore, in order to determine whether the leakage test valve set in the intermediate shaft seal leakage rate test system for high-pressure cylinders is a suitable leakage test valve, it is necessary to first calculate the steam flow rate through the leakage test valve under rated operating conditions, so as to determine whether the leakage test valve is suitable based on the steam flow rate through the leakage test valve.

[0074] Optionally, the first operating parameters may include the operating parameters of the intermediate shaft seal leakage rate test system for the high-pressure cylinder and the parameters of the leakage test valve. The operating parameters of the intermediate shaft seal leakage rate test system for the high-pressure cylinder may include: the steam pressure P after the regulating stage of the high-pressure cylinder. csd and steam temperature t csd Steam pressure P before the inlet valve of the intermediate pressure cylinder IPin1d The design pressure loss PS of the intermediate pressure cylinder inlet valve; parameters of the leakage test valve may include: the critical pressure drop ratio x of the leakage test valve. T Valve flow coefficient K v .

[0075] See Figure 1 Steam pressure P after the high-pressure cylinder regulating stage csdfor Figure 1 The steam pressure at point A and the steam temperature t after the high-pressure cylinder regulating stage. csd for Figure 1 The steam temperature at point A in the diagram.

[0076] Steam pressure P before the inlet valve of the intermediate pressure cylinder IPin1d for Figure 1 Steam pressure at point B.

[0077] Depending on the type of leakage test valve, parameters such as the critical pressure drop ratio, valve flow coefficient, and connecting pipe inner diameter can be obtained from the manufacturer's information.

[0078] Step 202: Calculate the steam flow rate through the leakage test valve based on the first operating parameters.

[0079] After obtaining the first set of operating parameters, the steam flow rate through the leakage test valve is calculated based on these parameters, which may include:

[0080] First, based on the steam pressure P before the inlet valve of the intermediate pressure cylinder... IPin1d Given the design pressure loss PS of the intermediate pressure cylinder inlet valve, calculate the intermediate pressure cylinder inlet pressure under rated operating conditions when the leakage test valve is fully open. Figure 1 The steam pressure at point C.

[0081] Optional, according to Calculate the inlet steam pressure of the intermediate pressure cylinder when the leakage test valve is fully open under rated operating conditions; where P IPin3d This indicates the inlet steam pressure of the intermediate pressure cylinder when the leakage test valve is fully open under rated operating conditions.

[0082] Then, based on the intermediate pressure cylinder inlet steam pressure P when the leakage test valve is fully open under rated operating conditions... IPin3d Steam pressure P after the high-pressure cylinder regulating stage csd Calculate the steam pressure at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions.

[0083] Optional, according to Calculate the steam pressure at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions; where P vind This indicates the steam pressure at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions. 'n' represents the total number of shaft seal stages installed on the intermediate shaft seal leakage passage of the high-pressure cylinder. 'm' represents the number of shaft seal stages upstream of the location where the leakage branch pipeline connects to the intermediate shaft seal leakage passage of the high-pressure cylinder. Note that the count is along the direction of shaft seal leakage steam flow. See [reference needed]. Figure 1As shown, following the arrow direction on the intermediate shaft seal leakage passage of the high-pressure cylinder, counting from left to right up to the m-th stage shaft seal, and before the (m+1)-th stage shaft seal, a leakage branch pipeline is installed.

[0084] Then, based on the high-pressure cylinder regulating stage steam pressure P when the leakage test valve is fully open under rated operating conditions... csd and steam temperature t csd Steam pressure P at the inlet location of the leaking branch pipe vind Calculate the steam temperature at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions;

[0085] Optional, depending on t vind =tph[P vind ,hpt(P csd ,t csd )] Calculate the steam temperature at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions; where t vind This represents the steam temperature at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions. hpt(P,t) is the steam-water characteristic function for calculating the enthalpy of the medium based on the medium pressure and temperature, and tph(P,h) is the steam-water characteristic function for calculating the enthalpy of the medium based on the medium pressure and enthalpy.

[0086] Finally, based on the critical pressure drop ratio x of the leakage test valve T Valve flow coefficient K v The steam pressure P at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions. vind and the steam temperature t of the leaking branch pipe vind Calculate the steam flow rate through the leakage test valve;

[0087] Optional, according to Calculate the steam flow rate through the leakage test valve;

[0088] In the formula, Cppt(P,t) represents the steam-water characteristic function for solving the isobaric specific heat of the medium based on the medium pressure and temperature, Cvpt(P,t) represents the steam-water characteristic function for solving the isovolic specific heat of the medium based on the medium pressure and temperature, and vpt(P,t) represents the steam-water characteristic function for solving the specific volume of the medium based on the medium pressure and temperature.

[0089] Step 203: When the steam flow rate meets the first preset condition, obtain the second operating parameters corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder when the leakage test valve is in the fully open or fully closed state under different preset operating conditions, and calculate the intermediate shaft seal leakage rate of the high-pressure cylinder based on the second operating parameters.

[0090] See Figure 3As shown, the steps preceding this one include:

[0091] Check whether the steam flow rate meets the first preset condition;

[0092] When the steam flow rate meets the first preset condition, proceed to step 203; when the steam flow rate does not meet the first preset condition, increase the size of the leakage test valve and replace the leakage test valve. Install the new leakage test valve on the leakage branch pipeline of the intermediate shaft seal leakage rate test system of the high-pressure cylinder, and jump to step 201 to re-execute until the steam flow rate meets the first preset condition.

[0093] In one embodiment, detecting whether the steam flow rate meets the first preset condition may include: detecting whether the steam flow rate is greater than a preset multiple of the design leakage flow rate of the intermediate shaft seal of the high-pressure cylinder; if the steam flow rate is greater than the preset multiple of the design leakage flow rate of the intermediate shaft seal of the high-pressure cylinder, then it is determined that the steam flow rate meets the first preset condition; otherwise, the steam flow rate does not meet the first preset condition.

[0094] The preset multiplier can be set according to requirements. For example, the preset multiplier can be 1.5 times. In this embodiment, the value of the preset multiplier is not limited.

[0095] Optional, see Figure 4 To obtain the second operating parameters corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder under different preset operating conditions, when the leakage test valve is in the fully open or fully closed state, and to calculate the intermediate shaft seal leakage rate of the high-pressure cylinder based on the second operating parameters, the following steps may be included:

[0096] Step 401: When the leakage test valve is in the fully open state, obtain the third operating parameter corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder under the current first preset operating condition, and the fourth operating parameter corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder under the current second preset operating condition.

[0097] The first preset operating condition differs from the second preset operating condition. However, it is important to note that the rated load of the unit in the first and second preset operating conditions must differ by more than 15% of the rated load. Otherwise, the rated load or output of the unit under the two preset operating conditions will be similar, causing the calculated intermediate-pressure cylinder flow efficiency to fail to meet the requirements. In one embodiment, the first preset operating condition can be a 50% rated load state, and the second preset operating condition can be a 75% rated load state. Since the calculation method used to calculate the intermediate-pressure cylinder flow efficiency is the same, the types of the measured third and fourth operating parameters are the same under different operating conditions, but the values ​​obtained are different.

[0098] The third operating parameter may include: the steam pressure P before the inlet valve of the intermediate pressure cylinder when the leakage test valve is fully open under the first preset operating condition.IPin1d 'and steam temperature t IPin1t 'The steam pressure P of the low-pressure connecting pipe at the outlet of the intermediate-pressure cylinder' IPexhd 'and steam temperature t IPexht '.

[0099] Steam pressure P before the inlet valve of the intermediate pressure cylinder IPin1d 'and steam temperature t IPin1t 'Right now Figure 1 Steam pressure and temperature at point B under 50% rated load. Pressure P of the low-pressure connecting pipe at the outlet of the intermediate-pressure cylinder. IPexhd 'and temperature t IPexht 'Right now Figure 1 The steam pressure and steam temperature of the low-pressure connecting pipe 11 at the outlet of the medium-pressure cylinder.

[0100] Step 402: Calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully open under the current first preset operating condition, based on the third operating parameter.

[0101] After obtaining the third operating parameter, calculating the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully open under the current first preset operating condition can include:

[0102] Firstly, based on the current first preset operating condition where the leakage test valve is fully open, the steam pressure P before the inlet valve of the intermediate pressure cylinder is... IPin1d 'Calculate the design pressure loss of the intermediate pressure cylinder inlet valve and the intermediate pressure cylinder inlet pressure when the leakage test valve is fully open under the current first preset working condition.'

[0103] Optional, according to Calculate the inlet steam pressure of the intermediate pressure cylinder when the leakage test valve is fully open under the current first preset operating condition; where P IPin3d 'Indicates the steam inlet pressure of the intermediate pressure cylinder when the leakage test valve is fully open under the current first preset operating condition.

[0104] Then, based on the current first preset operating condition where the leakage test valve is fully open, the steam pressure P before the inlet valve of the intermediate pressure cylinder is... IPin1d 'and steam temperature t IPin1t '、Intermediate pressure cylinder inlet steam pressure P IPin3d 'Calculate the inlet steam temperature of the intermediate pressure cylinder when the leakage test valve is fully open under the current first preset operating condition, i.e., calculate...' Figure 1 The steam inlet temperature at point C.

[0105] Optional, depending on t IPin3t '=tph[P IPin3d ',hpt(P IPin1d ',t IPin1t')] Calculate the inlet steam temperature of the intermediate pressure cylinder when the leakage test valve is fully open under the current first preset operating condition, where t IPin3t ' represents the steam inlet temperature of the intermediate pressure cylinder when the leakage test valve is fully open under the current first preset working condition, hpt(P,t) is the steam-water characteristic function for solving the enthalpy of the medium based on the medium pressure and temperature, and tph(P,h) is the steam-water characteristic function for solving the enthalpy of the medium based on the medium pressure and enthalpy.

[0106] Finally, based on the current first preset operating condition, when the leakage test valve is in the fully open state, the steam pressure P before the inlet valve of the intermediate pressure cylinder is... IPin1d 'and steam temperature t IPin1t '、Intermediate pressure cylinder inlet steam temperature P IPin3d 'and inlet steam temperature t IPin3t ', Steam pressure P in the low-pressure connecting pipe at the outlet of the intermediate-pressure cylinder IPexhd 'and steam temperature t IPexht 'Calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully open under the current first preset working condition;

[0107] Optional, according to

[0108] Calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully open under the current first preset operating condition; where η IP ' represents the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully open under the current first preset working condition, spt(P,t) represents the steam-water characteristic function that solves the entropy value of the medium based on the medium pressure and temperature, and hps(P,s) represents the steam-water characteristic function that solves the enthalpy value of the medium based on the medium pressure and entropy value.

[0109] Step 403: Calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully open under the current second preset operating condition, based on the fourth operating parameter.

[0110] This step is the same as the calculation method in step 402 for calculating the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully open under the current second preset working condition. The only difference is the operating parameters used, so it will not be repeated here.

[0111] Step 404: If the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully open under the current first preset operating condition and the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully open under the current second preset operating condition meet the second preset condition, obtain the fifth operating parameter corresponding to the intermediate shaft seal leakage rate test system of the high and medium pressure cylinder when the leakage test valve is fully closed under the current second preset operating condition.

[0112] In one embodiment, see Figure 3As shown, after step 403 and before step 404, the process further includes: detecting whether the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the current first preset operating condition and the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the current second preset operating condition meet the second preset condition; if they meet the condition, step 404 is executed; if they do not meet the condition, the rated load of the unit under the first preset operating condition and the second preset operating condition is reduced to obtain a new first preset operating condition and a new second preset operating condition, and the process jumps to the step of "obtaining the third operating parameter corresponding to the intermediate shaft seal leakage rate test system under the current first preset operating condition and the fourth operating parameter corresponding to the intermediate shaft seal leakage rate test system under the current second preset condition when the leakage test valve is fully open" and subsequent steps are executed until the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the current first preset operating condition and the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the current second preset condition meet the second preset condition.

[0113] When the unit's rated load is reduced by 50% and 75%, the actual leakage of the intermediate shaft seal leakage channel of the intermediate and high-pressure cylinders can be reduced, thereby enabling the flow efficiency of the intermediate-pressure cylinders to meet the second preset condition.

[0114] Optionally, reducing the unit's rated load by 50% and 75% can result in a new first preset operating condition with 45% and 60% rated load, respectively.

[0115] In one embodiment, detecting whether the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully open under the current first preset operating condition and the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully open under the current second preset operating condition satisfy the second preset condition may include:

[0116] The system checks whether the absolute value of the difference between the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the current first preset operating condition and the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the current second preset operating condition is less than a preset value. If the absolute value of the difference between the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the current first preset operating condition and the current second preset operating condition is less than the preset value, it is determined that the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the current first preset operating condition and the current second preset operating condition does not meet the second preset condition.

[0117] The preset value can be set according to requirements, but it is not limited in this embodiment. For example, the preset value can be a fixed value of 0.1%.

[0118] In one embodiment, the fifth operating parameter may include: the steam pressure P after the high-pressure cylinder regulating stage when the leakage test valve is fully closed under the second preset operating condition. cst VC and steam temperature t cst VC Steam pressure P before the inlet valve of the intermediate pressure cylinder IPin1d VC and steam temperature t IPin1d VC Steam pressure P in the medium-pressure cylinder outlet low-pressure connecting pipeline IPexhd VC and steam temperature t IPexht VC .

[0119] Step 405: Calculate the steam leakage rate of the intermediate shaft seal of the high-pressure cylinder based on the fifth operating parameter.

[0120] In one embodiment, calculating the shaft seal leakage rate of the shaft seal leakage pipeline between the high-pressure cylinder and the intermediate-pressure cylinder based on the fifth operating parameter may include:

[0121] The leakage rate of the intermediate shaft seal in the high-pressure cylinder is assigned as a preset leakage rate. In this embodiment, we first assume the preset leakage rate and then verify it. If the verification fails, we re-assume a new leakage rate. If the verification succeeds, the assumed leakage rate is the desired leakage rate of the intermediate shaft seal in the high-pressure cylinder. Here, the leakage rate of the intermediate shaft seal in the high-pressure cylinder is the leakage rate of the leakage channel of the intermediate shaft seal in the high-pressure cylinder.

[0122] Based on the fifth operating parameter and the current preset shaft seal leakage rate, calculate the medium-pressure cylinder flow efficiency when the leakage test valve is fully closed under the second preset operating condition.

[0123] When the flow efficiency of the intermediate pressure cylinder under the second preset operating condition when the leakage test valve is fully open and the flow efficiency of the intermediate pressure cylinder under the second preset operating condition when the leakage test valve is fully closed meet the third preset condition, the preset shaft seal leakage rate is determined to be the intermediate shaft seal leakage rate of the intermediate and high pressure cylinders.

[0124] In one embodiment, calculating the intermediate-pressure cylinder flow efficiency under the second preset operating condition when the leakage test valve is fully closed, based on the fifth operating parameter and the current preset shaft seal leakage rate, may include:

[0125] Based on the fifth operating parameter and the current preset shaft seal leakage rate, calculate the enthalpy value of the intermediate pressure cylinder inlet steam when the leakage test valve is fully closed under the second preset operating condition;

[0126] Based on the enthalpy of the intermediate pressure cylinder inlet steam and the steam pressure before the intermediate pressure cylinder inlet valve when the leakage test valve is fully closed under the second preset operating condition, calculate the intermediate pressure cylinder inlet steam temperature when the leakage test valve is fully closed under the second preset operating condition.

[0127] Based on the enthalpy of the inlet steam before the inlet steam valve of the intermediate pressure cylinder, the inlet steam temperature of the intermediate pressure cylinder, and the fifth operating parameter when the leakage test valve is fully closed under the second preset operating condition, the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition is calculated.

[0128] Optionally, based on the fifth operating parameter and the current preset shaft seal leakage rate, the enthalpy value of the intermediate-pressure cylinder inlet steam when the leakage test valve is fully closed under the second preset operating condition can be calculated. This may include: based on the steam pressure P after the high-pressure cylinder regulating stage when the leakage test valve is fully closed under the second preset operating condition. cst VC and steam temperature t cst VC Steam pressure P before the inlet valve of the intermediate pressure cylinder IPin1d VC and steam temperature t IPin1d VC Preset shaft seal leakage rate R l Calculate the enthalpy of the steam entering the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition.

[0129] Optional, according to Calculate the enthalpy of the steam entering the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition;

[0130] Among them, h IPin3d VC R represents the enthalpy of the steam entering the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition. l This indicates the preset shaft seal leakage rate.

[0131] In one embodiment, calculating the intermediate-pressure cylinder inlet steam temperature under the second preset operating condition (when the leakage test valve is fully closed) based on the intermediate-pressure cylinder inlet steam enthalpy and the steam pressure before the intermediate-pressure cylinder inlet valve under the second preset operating condition can include: calculating the intermediate-pressure cylinder inlet steam temperature based on the intermediate-pressure cylinder inlet steam pressure P when the leakage test valve is fully closed under the second preset operating condition. IPin1d VC Calculate the intermediate pressure cylinder inlet steam pressure P when the leakage test valve is fully closed under the second preset operating condition. IPin3d VC According to the intermediate pressure cylinder inlet steam pressure P when the leakage test valve is fully closed under the second preset working condition. IPin3d VC and the enthalpy value of steam entering the intermediate pressure cylinder h IPin3d VCCalculate the intermediate pressure cylinder inlet steam temperature t when the leakage test valve is fully closed under the second preset operating condition. IPin3t VC .

[0132] Optional, according to Calculate the inlet steam temperature of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition.

[0133] In one embodiment, the fifth operating parameter further includes: the steam pressure P in the low-pressure connecting pipeline at the outlet of the intermediate-pressure cylinder. IPexhd VC and steam temperature t IPexht VC ;

[0134] Based on the enthalpy value h of the steam inlet valve before the intermediate pressure cylinder inlet valve when the leakage test valve is fully closed under the second preset working condition. IPin3d VC Intermediate pressure cylinder inlet steam temperature t IPin3t VC Based on the fifth operating parameter, calculate the medium-pressure cylinder flow efficiency η when the leakage test valve is fully closed under the second preset operating condition. IP VC Here, the fifth operating parameter can be the steam pressure P in the low-pressure connecting pipeline at the outlet of the intermediate-pressure cylinder. IPexhd VC and steam temperature t IPexht VC It can include:

[0135] Optional, according to Calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully closed under the second preset operating condition; where η IP VC denoted as the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully closed under the second preset working condition, spt(P,t) represents the steam-water characteristic function that solves the entropy value of the medium based on the medium pressure and temperature, and hps(P,s) represents the steam-water characteristic function that solves the enthalpy value of the medium based on the medium pressure and entropy value.

[0136] After calculating the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully closed under the second preset working condition, it is checked whether the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully open under the second preset working condition and the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully closed under the second preset working condition meet the third preset condition.

[0137] When the flow efficiency of the intermediate pressure cylinder under the second preset operating condition when the leakage test valve is fully open and the flow efficiency of the intermediate pressure cylinder under the second preset operating condition when the leakage test valve is fully closed meet the third preset condition, the preset shaft seal leakage rate is determined to be the intermediate shaft seal leakage rate of the intermediate and high pressure cylinders.

[0138] When the flow efficiency of the intermediate-pressure cylinder under the second preset operating condition when the leakage test valve is fully open and the flow efficiency of the intermediate-pressure cylinder under the second preset operating condition when the leakage test valve is fully closed do not meet the third preset condition, the intermediate shaft seal leakage rate of the intermediate-pressure cylinder is assigned as a new preset shaft seal leakage rate. Calculations are then performed based on the fifth operating parameter and the current preset shaft seal leakage rate until the flow efficiency of the intermediate-pressure cylinder under the second preset operating condition when the leakage test valve is fully open and the flow efficiency of the intermediate-pressure cylinder under the second preset operating condition when the leakage test valve is fully closed meets the third preset condition. The new shaft seal leakage rate is then determined to be the intermediate shaft seal leakage rate of the intermediate-pressure cylinder.

[0139] The detection of whether the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the second preset operating condition and when the leakage test valve is fully closed under the second preset operating condition meets the third preset condition can include: detecting whether the absolute value of the difference between the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the second preset operating condition and when the leakage test valve is fully closed under the second preset operating condition is less than a preset value. If the absolute value of the difference between the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the second preset operating condition and when the leakage test valve is fully closed under the second preset operating condition is less than the preset value, it is determined that the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the second preset operating condition and when the leakage test valve is fully closed under the second preset operating condition meets the third preset condition; otherwise, it is determined that the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the second preset operating condition and when the leakage test valve is fully closed does not meet the third preset condition.

[0140] The default value here can be 0.1%.

[0141] This invention provides an embodiment of a test system for the leakage rate of intermediate shaft seals in high-pressure and intermediate-pressure cylinders. The system acquires first operating parameters under rated operating conditions when the leakage test valve is fully open. Based on these first operating parameters, it calculates the steam flow rate through the leakage test valve. When the steam flow rate meets a first preset condition, it acquires second operating parameters corresponding to the leakage rate test system under different preset operating conditions when the leakage test valve is fully open or fully closed. Based on these second operating parameters, it calculates the leakage rate of the intermediate shaft seals in high-pressure and intermediate-pressure cylinders. This allows for accurate and efficient calculation of the leakage rate of intermediate shaft seals in high-pressure and intermediate-pressure cylinders based on the measured operating parameters of the turbine under different load conditions with the leakage test valve fully open and fully closed. This solves the problem in the prior art where the large workload of on-site testing and adjustment when using variable steam temperature and other testing methods to determine the leakage rate of intermediate shaft seals in high-pressure and intermediate-pressure cylinders leads to inefficient and inaccurate monitoring of the leakage status of intermediate shaft seals in turbines.

[0142] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0143] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for calculating the steam leakage rate of intermediate shaft seals in high-pressure cylinders, characterized in that, A steam leakage rate testing system for intermediate shaft seals of high-pressure cylinders is adopted, including: leakage branch pipelines, leakage test valves and condensers; The steam inlet of the leakage branch pipeline is connected to the intermediate shaft seal leakage channel of the high-pressure cylinder, and the steam outlet of the leakage branch pipeline is connected to the condenser; n-stage shaft seals are arranged on the intermediate shaft seal leakage channel of the high-pressure cylinder, and the leakage branch pipeline to the condenser is connected to the m-stage shaft seal along the direction of leakage steam flow, where n and m are positive integers, and m is less than n; the leakage test valve is installed on the leakage branch pipeline; The calculation methods for the steam leakage rate of intermediate shaft seals in high-pressure cylinders include: Obtain the first operating parameters of the intermediate shaft seal leakage rate testing system of the high-pressure cylinder under rated operating conditions, with the leakage test valve in the fully open state; the first operating parameters include: the critical pressure drop ratio of the leakage test valve. Valve flow coefficient When the leakage test valve is fully open under rated operating conditions, the steam pressure after the high-pressure cylinder regulating stage is... and steam temperature Steam pressure before the inlet valve of the intermediate pressure cylinder The design pressure loss of the intermediate pressure cylinder steam inlet valve ; Based on the first operating parameters, calculate the steam flow rate through the leakage test valve; including: Based on the steam pressure before the inlet valve of the intermediate pressure cylinder Design pressure loss of the intermediate pressure cylinder inlet valve Calculate the inlet steam pressure of the intermediate pressure cylinder when the leakage test valve is fully open under rated operating conditions; Based on the intermediate pressure cylinder inlet steam pressure when the leakage test valve is fully open under rated operating conditions. Steam pressure after high-pressure cylinder regulating stage Calculate the steam pressure at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions; Based on the steam pressure after the high-pressure cylinder regulating stage when the leakage test valve is fully open under rated operating conditions. and steam temperature Steam pressure at the inlet of the leaking branch pipe Calculate the steam temperature at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions; Based on the critical pressure drop ratio of the leakage test valve Valve flow coefficient The steam pressure at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions. and the steam temperature of the leaking branch pipe Calculate the steam flow rate through the leakage test valve; When the steam flow rate meets the first preset condition, the second operating parameters corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder are obtained under different preset operating conditions when the leakage test valve is in the fully open or fully closed state, and the intermediate shaft seal leakage rate of the high-pressure cylinder is calculated based on the second operating parameters.

2. The method for calculating the steam leakage rate of the intermediate shaft seal of a high-pressure cylinder according to claim 1, characterized in that, The step of calculating the steam flow rate through the leakage test valve based on the first operating parameters includes: according to Calculate the inlet steam pressure of the intermediate pressure cylinder when the leakage test valve is fully open under rated operating conditions; according to Calculate the steam pressure at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions; according to Calculate the steam temperature at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions; according to Calculate the steam flow rate through the leakage test valve; in, This indicates the steam flow rate passing through the aforementioned leakage test valve. This indicates the inlet steam pressure of the intermediate pressure cylinder when the leakage test valve is fully open under rated operating conditions. This indicates the steam pressure at the inlet position of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions. This indicates the steam temperature at the inlet of the leakage branch pipeline when the leakage test valve is fully open under rated operating conditions. To determine the enthalpy of a medium using a steam-water characteristic function based on its pressure and temperature, To determine the steam-water characteristic function based on the medium pressure and enthalpy, This represents the steam-water characteristic function for calculating the isobaric specific heat of a medium based on its pressure and temperature. This represents the steam-water characteristic function obtained by calculating the specific heat at constant volume of the medium based on its pressure and temperature. This represents the steam-water characteristic function that calculates the specific volume of a medium based on its pressure and temperature.

3. The method for calculating the steam leakage rate of the intermediate shaft seal of a high-pressure cylinder according to claim 1, characterized in that, Determining that the steam flow rate meets the first preset condition includes: When the steam flow rate is greater than a preset multiple of the design leakage flow rate of the intermediate shaft seal of the high-pressure cylinder, it is determined that the steam flow rate meets the first preset condition. It also includes: when the steam flow rate does not meet the first preset condition, replacing the leakage test valve and jumping to the step of "obtaining the first operating parameters of the intermediate shaft seal leakage rate test system of the high-pressure cylinder under rated operating conditions when the leakage test valve is in the fully open state" and subsequent steps until the steam flow rate meets the first preset condition.

4. The method for calculating the steam leakage rate of the intermediate shaft seal of the high-pressure cylinder according to claim 2, characterized in that, The second operating parameter includes the third operating parameter, the fourth operating parameter, and the fifth operating parameter; The process of obtaining the second operating parameters corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder under different preset operating conditions, when the leakage test valve is in the fully open or fully closed state, and calculating the intermediate shaft seal leakage rate of the high-pressure cylinder based on the second operating parameters, includes: When the leakage test valve is fully open, the third operating parameter corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder under the current first preset operating condition and the fourth operating parameter corresponding to the intermediate shaft seal leakage rate test system of the high-pressure cylinder under the current second preset operating condition are obtained. The rated load of the unit under the first preset operating condition and the second preset operating condition differs by more than 15% of the rated load. Based on the third operating parameter, calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is in the fully open state under the current first preset operating condition; Based on the fourth operating parameter, calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully open under the current second preset operating condition; When the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully open under the current first preset operating condition and the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully open under the current second preset operating condition meet the second preset condition, the fifth operating parameter corresponding to the leakage rate test system of the intermediate shaft seal of the high and medium pressure cylinder when the leakage test valve is fully closed under the current second preset operating condition is obtained. Calculate the steam leakage rate of the intermediate shaft seal of the high-pressure cylinder based on the fifth operating parameter.

5. The method for calculating the steam leakage rate of the intermediate shaft seal of a high-pressure cylinder according to claim 4, characterized in that, Also includes: When the intermediate-pressure cylinder flow efficiency under the current first preset operating condition with the leakage test valve fully open and the intermediate-pressure cylinder flow efficiency under the current second preset operating condition with the leakage test valve fully open do not meet the second preset condition, the rated load of the unit under the first preset operating condition and the second preset operating condition is reduced to obtain a new first preset operating condition and a new second preset operating condition. Then, the process jumps to the step "when the leakage test valve is fully open, obtain the third operating parameter corresponding to the intermediate shaft seal leakage rate test system of the intermediate-pressure cylinder under the current first preset operating condition, and the fourth operating parameter corresponding to the intermediate shaft seal leakage rate test system of the intermediate-pressure cylinder under the current second preset condition" and subsequent steps until the intermediate-pressure cylinder flow efficiency under the current first preset operating condition with the leakage test valve fully open and the intermediate-pressure cylinder flow efficiency under the current second preset operating condition meet the second preset condition.

6. The method for calculating the steam leakage rate of the intermediate shaft seal of the high-pressure cylinder according to claim 4, characterized in that, The calculation of the intermediate shaft seal leakage rate of the high-pressure cylinder based on the fifth operating parameter includes: The intermediate shaft seal leakage rate of the high-pressure cylinder is assigned the preset shaft seal leakage rate. Based on the fifth operating parameter and the current preset shaft seal leakage rate, calculate the medium-pressure cylinder flow efficiency when the leakage test valve is fully closed under the second preset operating condition. When the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully open under the second preset operating condition and the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition meet the third preset condition, the preset shaft seal leakage rate is determined to be the intermediate shaft seal leakage rate of the intermediate high-pressure cylinder.

7. The method for calculating the steam leakage rate of the intermediate shaft seal of a high-pressure cylinder according to claim 6, characterized in that, The step of calculating the intermediate-pressure cylinder flow efficiency under the second preset operating condition when the leakage test valve is in the fully closed state, based on the fifth operating parameter and the current preset shaft seal leakage rate, includes: Based on the fifth operating parameter and the current preset shaft seal leakage rate, calculate the enthalpy value of the intermediate pressure cylinder inlet steam when the leakage test valve is in the fully closed state under the second preset operating condition; Based on the inlet steam enthalpy value and the steam pressure before the inlet steam valve of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition, calculate the inlet steam temperature of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition. Based on the enthalpy of the inlet steam before the inlet steam valve of the intermediate pressure cylinder, the inlet steam temperature of the intermediate pressure cylinder, and the fifth operating parameter when the leakage test valve is in the fully closed state under the second preset operating condition, the flow efficiency of the intermediate pressure cylinder when the leakage test valve is in the fully closed state is calculated.

8. The method for calculating the steam leakage rate of the intermediate shaft seal of a high-pressure cylinder according to claim 6, characterized in that, Also includes: When the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the second preset operating condition and the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully closed under the second preset operating condition do not meet the third preset condition, the intermediate shaft seal leakage rate of the high-pressure cylinder is assigned a new preset shaft seal leakage rate, and calculations are performed based on the fifth operating parameter and the current preset shaft seal leakage rate until the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully open under the second preset operating condition and the flow efficiency of the intermediate-pressure cylinder when the leakage test valve is fully closed under the second preset operating condition meet the third preset condition, and the new shaft seal leakage rate is determined to be the intermediate shaft seal leakage rate of the high-pressure cylinder.

9. The method for calculating the steam leakage rate of the intermediate shaft seal of a high-pressure cylinder according to claim 7, characterized in that, The fifth operating parameter includes: the steam pressure after the high-pressure cylinder regulating stage when the leakage test valve is fully closed under the second preset operating condition. and steam temperature Steam pressure before the inlet valve of the intermediate pressure cylinder and steam temperature Steam pressure at the outlet of the intermediate-pressure cylinder and the connecting pipeline between the medium and low pressure and steam temperature ; The step of calculating the enthalpy of the intermediate-pressure cylinder inlet steam when the leakage test valve is fully closed under the second preset operating condition, based on the fifth operating parameter and the current preset shaft seal leakage rate, includes: according to Calculate the enthalpy of the steam entering the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition; in, This indicates the enthalpy value of the steam entering the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition. Indicates the preset shaft seal leakage rate; Based on the inlet steam enthalpy and the steam pressure before the intermediate pressure cylinder inlet valve when the leakage test valve is fully closed under the second preset operating condition, the intermediate pressure cylinder inlet steam temperature when the leakage test valve is fully closed under the second preset operating condition is calculated, including: according to Calculate the inlet steam temperature of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition; in, This indicates the inlet steam pressure of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition. This indicates the inlet steam temperature of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition; Based on the enthalpy of the inlet steam before the inlet steam valve of the intermediate pressure cylinder, the inlet steam temperature of the intermediate pressure cylinder, and the fifth operating parameter when the leakage test valve is fully closed under the second preset operating condition, the flow efficiency of the intermediate pressure cylinder when the leakage test valve is fully closed under the second preset operating condition is calculated, including: according to Calculate the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully closed under the second preset working condition; in, This indicates the flow efficiency of the medium-pressure cylinder when the leakage test valve is fully closed under the second preset operating condition. This represents a steam-water characteristic function that calculates the entropy of a medium based on its pressure and temperature. This represents a steam-water characteristic function that calculates the enthalpy of a medium based on its pressure and entropy.

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