A feedwater pump turbine performance monitoring system and monitoring method

Abstract

The present invention discloses a feedwater pump steam turbine performance monitoring system and monitoring method, including a condensate pipeline, a boiler, a deaerator, a first heater, a second heater, a third heater, a high-pressure cylinder, a reheat pipeline, a reheat desuperheating water pipe, a medium-pressure cylinder, a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a flow from the fourth pumping section to the middle discharge section, a feedwater pump steam turbine, and a pressure measuring device, a temperature measuring device, and a differential pressure measuring device. The present invention has the advantage that the operating efficiency of the feedwater pump steam turbine can be accurately calculated by measuring the values ​​of each pipeline and equipment through the pressure measuring device, the temperature measuring device, and the differential pressure measuring device, without the need for measurement through an orifice plate, thereby improving the accuracy of the performance monitoring of the feedwater pump steam turbine.

Description

Technical Field

[0001] The invention relates to the technical field of feedwater pump steam turbines, and in particular to a feedwater pump steam turbine performance monitoring system and a monitoring method. Background Art

[0002] At present, most of my country's thermal power units of 300MW and above use steam-driven feedwater pumps to provide power for the power generation medium. The steam-driven feedwater pump uses a feedwater pump turbine that matches it to provide driving force. The operating performance or operating efficiency of the steam-driven feedwater pump and feedwater pump turbine unit is a relatively important economic parameter. For example, China's invention patent publication number CN111535873A discloses a method for online monitoring of the efficiency of a feedwater pump turbine unit based on historical data to calculate the operating efficiency of the feedwater pump turbine unit.

[0003] When studying the operating efficiency of steam-driven feedwater pumps and feedwater pump steam turbine units, a very important parameter is the steam flow rate that drives the feedwater pump steam turbine. Taking a 600MW steam turbine as an example, the steam parameters entering the feedwater pump steam turbine are about 1MPa and 400℃. The steam flow rate here is generally measured by orifice plate flow differential pressure measurement. For the orifice plate that has just been put into operation, the measurement accuracy can meet the requirements of the test and on-site monitoring. However, after a long period of operation, the orifice plate will inevitably be blocked or eroded, which will affect the measurement accuracy. This is not conducive to on-site performance monitoring and is not conducive to the monitoring of the operating performance of the feedwater pump steam turbine. In addition, when conducting the performance test of the feedwater pump steam turbine, inaccurate results will be obtained due to the problem of orifice plate flow measurement, and it is impossible to accurately guide maintenance. Summary of the invention

[0004] The technical problem to be solved by the present invention is how to improve the accuracy of monitoring the performance of a feedwater pump turbine.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A feedwater pump steam turbine performance monitoring system includes a condensate pipeline, a boiler, a deaerator, a first heater, a second heater, a third heater, a high-pressure cylinder, a reheat pipeline, a reheat desuperheating water pipe, a medium-pressure cylinder, a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a flow from the fourth extraction to the middle discharge section, a feedwater pump steam turbine, and a pressure measuring device, a temperature measuring device, and a differential pressure measuring device.

[0007] The condensate pipe is connected to the high-pressure cylinder after passing through the boiler. A deaerator, a first heater, a second heater and a third heater are sequentially arranged on the condensate pipe along the flow direction of the condensate. A reheat pipe, a first-stage pipe and a second-stage pipe are arranged at the output end of the high-pressure cylinder. The reheat pipe is connected to the medium-pressure cylinder after passing through the reheating cooling water pipe and the boiler in sequence. The output end of the first-stage pipe is connected to the second heater, and the output end of the second-stage pipe is connected to the third heater.

[0008] The output end of the medium-pressure cylinder is provided with three-section pipelines, four-section pipelines and a flow passage from four pumping sections to the middle discharge section. The output end of the three-section pipeline is connected to the first heater, the output end of the four-section pipeline is divided into two and respectively connected to the feed water pump turbine and the deaerator, and the flow passage from the four pumping sections to the middle discharge section is connected to an external mechanism.

[0009] The output end of the third heater is connected to the second heater, the output end of the second heater is connected to the first heater, and the output end of the first heater is connected to the deaerator.

[0010] The input and output ends of the condensate pipe, the output end of the reheat pipe, the first pipe, the second pipe, the third pipe, the fourth pipe and the flow from the fourth extraction to the middle row are all provided with pressure measuring devices and temperature measuring devices. The condensate pipes between the deaerator, the first heater, the second heater and the third heater are all provided with temperature measuring devices. The pipe connecting the third heater to the second heater, the pipe connecting the second heater to the first heater and the pipe connecting the first heater to the deaerator are all provided with temperature measuring devices. The input ends of the reheat and desuperheating water pipes and the condensate pipes are all provided with differential pressure measuring devices. The input end of the feed pump turbine is provided with a pressure measuring device.

[0011] The operating efficiency of the feedwater pump turbine is accurately calculated by measuring the values ​​of each pipeline and equipment through pressure measuring instruments, temperature measuring instruments and differential pressure measuring instruments. There is no need to measure through orifice plates, which improves the accuracy of feedwater pump turbine performance monitoring.

[0012] Preferably, the first heater, the second heater and the third heater are all high-voltage heaters.

[0013] Preferably, the pressure measuring device is a pressure transmitter.

[0014] Preferably, the temperature measuring device is a thermocouple or a thermal resistor.

[0015] Preferably, the differential pressure measuring device is a differential pressure transmitter.

[0016] Preferably, the present invention also provides a monitoring method for a feedwater pump turbine performance monitoring system, comprising the following steps:

[0017] Step 1: Select the base case

[0018] The benchmark operating condition can be the performance assessment test results of a newly commissioned feedwater pump steam turbine unit or the performance acceptance test data of a modified feedwater pump steam turbine unit;

[0019] Specific data involves unit load, main steam flow, reheat steam flow on reheat pipe, extraction pressure and extraction temperature of three-section pipe, extraction pressure and extraction temperature of four-section pipe, steam flow from four-section pipe to deaerator, steam flow from four-section extraction to feedwater pump turbine, exhaust pressure and exhaust flow of intermediate pressure cylinder. The above data are used as the reference library for subsequent steps.

[0020] Step 2: Calculate the actual operating condition feedwater pump turbine steam inlet flow

[0021] Step 2.1: Specifically, the condensate flow at the input end of the condensate pipe and the main steam pressure and temperature at the output end are detected by means of a pressure measuring device, a temperature measuring device and a differential pressure measuring device, and the following are obtained: the first extraction pressure and the first extraction temperature on the first pipe, the second extraction pressure and the second extraction temperature on the second pipe, the reheat steam pressure and the reheat steam temperature on the reheat pipe, the third extraction pressure and the third extraction temperature on the third pipe, the fourth extraction pressure and the fourth extraction temperature on the fourth pipe, the fifth extraction pressure and the fifth extraction temperature on the flow from the fourth extraction to the middle discharge section, the exhaust pressure of the feed pump turbine, the condensate pressure entering the deaerator, the condensate temperature entering the deaerator, the condensate flow entering the deaerator, the inlet temperature, the outlet temperature and the drain temperature of the first heater, the outlet temperature and the drain temperature of the second heater, the outlet temperature and the drain temperature of the third heater, and the reheat and cooling water flow of the reheat and cooling water pipe.

[0022] The heat balance method is used to obtain the following data under actual operating conditions: main steam flow, reheat steam flow on the reheat pipe, extraction steam flow of the first pipe, extraction steam flow of the second pipe, extraction steam flow of the third pipe, and steam flow from the fourth pipe to the deaerator.

[0023] Step 2.2: The data in the benchmark library are all known numbers. Since the flow area of ​​the four-section pipeline does not change after steam extraction, and the steam flow rate does not change, the steam flow rate from the fourth extraction to the middle row section is calculated using the formula.

[0024] Step 2.3: Taking the high-pressure cylinder as the research object, calculate the steam inlet flow rate of the medium-pressure cylinder according to the law of conservation of mass.

[0025] Step 2.4: Taking the intermediate pressure cylinder as the research object, calculate the steam inlet flow rate of the feedwater pump turbine according to the law of conservation of mass.

[0026] Step 3: Calculate the feedwater pump turbine operating efficiency under actual operating conditions.

[0027] Preferably, the steam flow rate G from the fourth extraction to the middle row section is 中1 The calculation is done using the following formula:

[0028]

[0029] Steam flow from the fourth extraction to the middle section:

[0030] In the above formula: subscript 0 is the reference working condition, subscript 1 is the actual working condition;

[0031] G 中 It is the steam flow rate from the fourth extraction to the middle discharge section;

[0032] P4 is the steam pressure of the four-section pipeline;

[0033] P5 is the exhaust pressure of the intermediate pressure cylinder;

[0034] T4 is the steam extraction temperature of the four-section pipeline.

[0035] Preferably, the steam inlet flow rate G of the intermediate pressure cylinder is 热1 The calculation is performed using the following formula:

[0036] G 热1 =G 高1 +G 再1

[0037] In the above formula: G 热1 is the steam inlet flow rate of the intermediate pressure cylinder;

[0038] G 高1 is the exhaust flow of high pressure cylinder, G 高1 =G 主1 -G 11 -G 21 (Where: G 主1 is the main steam flow, G 11 is the steam extraction flow rate of a section of pipeline, G 12 is the steam extraction flow rate of the second-stage pipeline);

[0039] G 再1 It is the reheating and desuperheating water flow rate.

[0040] Preferably, the steam inlet flow rate G of the water pump turbine is 小1 The calculation is performed using the following formula:

[0041]

[0042] In the above formula: subscript 1 refers to the actual working condition;

[0043] G 小1 is the steam inlet flow rate of the feedwater pump turbine;

[0044] G热1 is the steam inlet flow rate of the intermediate pressure cylinder;

[0045] G 31 is the three-stage extraction steam flow;

[0046] G 除1 It is the flow rate from the four-stage steam extraction to the deaerator.

[0047] Preferably, the feedwater pump turbine operating efficiency The calculation is performed using the following formula:

[0048]

[0049] In the above formula: is the efficiency of the feedwater pump turbine;

[0050] is the feedwater pump shaft power;

[0051] is the steam inlet enthalpy of the feedwater pump turbine;

[0052] is the ideal exhaust enthalpy of the feedwater pump turbine.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] The operating efficiency of the feedwater pump turbine is accurately calculated by measuring the values ​​of each pipeline and equipment through pressure measuring instruments, temperature measuring instruments and differential pressure measuring instruments. There is no need to measure through orifice plates, which improves the accuracy of feedwater pump turbine performance monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The present invention is a schematic structural diagram of a feedwater pump turbine performance monitoring system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0056] In order to facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention is further described in conjunction with the accompanying drawings of the specification.

[0057] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0058] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0059] See also Figure 1 The present embodiment discloses a feedwater pump turbine performance monitoring system, comprising a condensate pipeline 1, a boiler 2, a deaerator 3, a first heater 4, a second heater 5, a third heater 6, a high-pressure cylinder 7, a reheat pipeline 8, a reheat desuperheating water pipe 9, an intermediate-pressure cylinder 10, a first-stage pipeline 11, a second-stage pipeline 12, a third-stage pipeline 13, a fourth-stage pipeline 14, a flow from the fourth extraction to the middle discharge section 15, a feedwater pump turbine 16, a pressure measuring device 17, a temperature measuring device 18, and a differential pressure measuring device 19.

[0060] The condensate pipe 1 is connected to the high-pressure cylinder 7 after passing through the boiler 2. The condensate pipe 1 is provided with a deaerator 3, a first heater 4, a second heater 5 and a third heater 6 in sequence along the condensate flow direction. In this embodiment, the first heater 4, the second heater 5 and the third heater 6 are all high-pressure heaters. The output end of the high-pressure cylinder 7 is provided with a reheat pipe 8, a first pipe 11 and a second pipe 12. The reheat pipe 8 is connected to the medium-pressure cylinder 10 after passing through the reheating and cooling water pipe 9 and the boiler 2 in sequence. The output end of the first pipe 11 is connected to the second heater 5, and the output end of the second pipe 12 is connected to the third heater 6.

[0061] The output end of the medium pressure cylinder 10 is provided with three sections of pipelines 13, four sections of pipelines 14 and a flow passage 15 from the fourth extraction section to the middle discharge section. The output end of the three sections of pipelines 13 is connected to the first heater 4, the output end of the four sections of pipelines 14 is divided into two and respectively connected to the feed water pump turbine 16 and the deaerator 3, and the flow passage 15 from the fourth extraction section to the middle discharge section is connected to an external mechanism (not shown in the figure).

[0062] The output end of the third heater 6 is connected to the second heater 5 , the output end of the second heater 5 is connected to the first heater 4 , and the output end of the first heater 4 is connected to the deaerator 3 .

[0063] The input and output ends of the condensate pipe 1, the output end of the reheat pipe 8, the first pipe 11, the second pipe 12, the third pipe 13, the fourth pipe 14 and the flow through 15 from the fourth extraction to the middle row are all provided with pressure measuring devices 17 and temperature measuring devices 18. The condensate pipe 1 between the deaerator 3, the first heater 4, the second heater 5 and the third heater 6 is provided with a temperature measuring device 18. The pipe connecting the third heater 6 to the second heater 5, the pipe connecting the second heater 5 to the first heater 4 and the pipe connecting the first heater 4 to the deaerator 3 are all provided with temperature measuring devices 18. The reheat and desuperheating water pipe 9 and the input end of the condensate pipe 1 are both provided with differential pressure measuring devices 19. The input end of the feed water pump turbine 16 is provided with a pressure measuring device 17.

[0064] In this embodiment, the pressure measuring device 17 is a pressure transmitter, the temperature measuring device 18 is a thermocouple or a thermal resistor, and the differential pressure measuring device 19 is a differential pressure transmitter.

[0065] This embodiment also discloses a monitoring method for a feedwater pump turbine performance monitoring system, comprising the following steps:

[0066] Step 1: Select the base case

[0067] The benchmark operating condition can be the performance assessment test results of a newly commissioned feedwater pump steam turbine unit or the performance acceptance test data of a modified feedwater pump steam turbine unit;

[0068] Specific data involve unit load, main steam flow, reheat steam flow on reheat pipe 8, extraction pressure and extraction temperature of three-section pipe 13, extraction pressure and extraction temperature of four-section pipe 14, steam flow from four-section pipe 14 to deaerator 3, steam flow from four-section extraction to feedwater pump turbine 16, exhaust pressure of intermediate pressure cylinder 10, exhaust flow of intermediate pressure cylinder 10. The above data are used as a reference library for subsequent steps.

[0069] Step 2: Calculate the actual operating condition feedwater pump turbine steam inlet flow

[0070] Step 2.1: Specifically, the condensate flow rate at the input end of the condensate pipe 1 and the main steam pressure and main steam temperature at the output end are detected by the pressure measuring device 17, the temperature measuring device 18 and the differential pressure measuring device 19, the first extraction steam pressure and the first extraction steam temperature on the first section pipe 11, the second extraction steam pressure and the second extraction steam temperature on the second section pipe 12, the reheat steam pressure and the reheat steam temperature on the reheat pipe 8, the third extraction steam pressure and the third extraction steam temperature on the third section pipe 13, and the fourth extraction steam pressure and the third extraction steam temperature on the fourth section pipe 14. The four-stage steam extraction pressure and four-stage steam extraction temperature, the five-stage steam extraction pressure and five-stage steam extraction temperature on the flow 15 from the four-stage extraction to the middle exhaust section, the exhaust pressure of the feed water pump turbine 16, the condensate pressure entering the deaerator 3, the condensate temperature entering the deaerator 3, the condensate flow entering the deaerator 3, the inlet water temperature, outlet water temperature and drain temperature of the first heater 4, the outlet water temperature and drain temperature of the second heater 5, the outlet water temperature and drain temperature of the third heater 6, and the reheating and cooling water flow of the reheating and cooling water pipe 9.

[0071] The heat balance method is used to obtain the following data under actual operating conditions: main steam flow, reheat steam flow on reheat pipe 8, extraction steam flow of first-stage pipe 11, extraction steam flow of second-stage pipe 12, extraction steam flow of third-stage pipe 13, and steam flow from fourth-stage pipe 14 to deaerator 3.

[0072] Step 2.2: The data in the benchmark database are all known numbers. Since the flow area of ​​the four-section pipeline 14 does not change after the steam extraction, and the steam flow rate does not change, the steam flow rate G from the four-section pipeline 14 to the middle section 15 is calculated using the following formula: 中1 :

[0073]

[0074] Steam flow from the fourth extraction to the middle section:

[0075] In the above formula: subscript 0 is the reference working condition, subscript 1 is the actual working condition;

[0076] G 中 It is the steam flow rate from the fourth extraction to the middle discharge section;

[0077] P4 is the steam pressure of the four-section pipeline;

[0078] P5 is the exhaust pressure of the intermediate pressure cylinder;

[0079] T4 is the extraction steam temperature of the four-section pipeline;

[0080] Step 2.3: Taking the high-pressure cylinder as the research object, according to the law of conservation of mass, the flow rates in and out of the high-pressure cylinder 7 are the same. The steam flow rate in the medium-pressure cylinder 10 is calculated using the following formula:

[0081] G 热1 =G高1 +G 再1

[0082] In the above formula: G 热1 is the steam inlet flow rate of the intermediate pressure cylinder;

[0083] G 高1 is the exhaust flow of high pressure cylinder, G 高1 =G 主1 -G 11 -G 21 (Where: G 主1 is the main steam flow, G 11 is the steam extraction flow rate of a section of pipeline, G 12 is the steam extraction flow rate of the second-stage pipeline);

[0084] G 再1 It is the reheating and desuperheating water flow;

[0085] Step 2.4: Taking the intermediate pressure cylinder as the research object, according to the law of conservation of mass, the flow rates in and out of the intermediate pressure cylinder 10 are the same. The following formula is used to calculate the steam inlet flow rate of the feedwater pump turbine 16:

[0086]

[0087] In the above formula: subscript 1 refers to the actual working condition;

[0088] G 小1 is the steam inlet flow rate of the feedwater pump turbine;

[0089] G 热1 is the steam inlet flow rate of the intermediate pressure cylinder;

[0090] G 31 is the steam extraction flow rate of the three-section pipeline;

[0091] G 除1 The flow rate of steam extraction from the four-section pipeline to the deaerator;

[0092] Step 3: Calculate the actual operating efficiency of the feedwater pump turbine

[0093]

[0094] In the above formula: is the efficiency of the feedwater pump turbine;

[0095] is the feedwater pump shaft power;

[0096] is the steam inlet enthalpy of the feedwater pump turbine, which is calculated by heat balance using the four-stage extraction steam pressure and four-stage extraction steam temperature measured on the four-stage pipeline 14;

[0097] is the ideal exhaust enthalpy of the feedwater pump steam turbine, which is calculated using the feedwater pump steam turbine exhaust pressure and heat balance.

[0098] The operating efficiency of the feedwater pump turbine is accurately calculated by measuring the values ​​of each pipeline and equipment through the pressure measuring device 17, the temperature measuring device 18 and the differential pressure measuring device 19. There is no need to measure through the orifice plate, thereby improving the accuracy of the performance monitoring of the feedwater pump turbine 16.

[0099] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0100] The above-described embodiments merely represent implementation methods of the invention. The protection scope of the present invention is not limited to the above-described embodiments. For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A feedwater pump turbine performance monitoring system, characterized in that: It includes condensate pipe, boiler, deaerator, first heater, second heater, third heater, high pressure cylinder, reheat pipe, reheat desuperheating water pipe, medium pressure cylinder, first pipe, second pipe, third pipe, fourth pipe, flow from the fourth extraction to the middle discharge section, feed water pump turbine, pressure measuring device, temperature measuring device and differential pressure measuring device; The condensate pipe is connected to the high-pressure cylinder after passing through the boiler. A deaerator, a first heater, a second heater and a third heater are sequentially arranged on the condensate pipe along the condensate flow direction. A reheat pipe, a first-stage pipe and a second-stage pipe are arranged at the output end of the high-pressure cylinder. The reheat pipe is sequentially connected to the medium-pressure cylinder after passing through the reheating cooling water pipe and the boiler. The output end of the first-stage pipe is connected to the second heater, and the output end of the second-stage pipe is connected to the third heater. The output end of the intermediate pressure cylinder is provided with three sections of pipelines, four sections of pipelines and a flow from the fourth section after extraction to the middle section. The output end of the three sections of pipelines is connected to the first heater, the output end of the four sections of pipelines is divided into two and respectively connected to the feedwater pump turbine and the deaerator, and the flow from the fourth section after extraction to the middle section is connected to an external mechanism; The output end of the third heater is connected to the second heater, the output end of the second heater is connected to the first heater, and the output end of the first heater is connected to the deaerator; The input and output ends of the condensate pipe, the output end of the reheat pipe, the first pipe, the second pipe, the third pipe, the fourth pipe and the flow from the fourth pumping to the middle row section are all provided with pressure measuring devices and temperature measuring devices. The condensate pipes between the deaerator, the first heater, the second heater and the third heater are all provided with temperature measuring devices. The pipe connecting the third heater to the second heater, the pipe connecting the second heater to the first heater and the pipe connecting the first heater to the deaerator are all provided with temperature measuring devices. The input ends of the reheat and desuperheating water pipes and the condensate pipes are all provided with differential pressure measuring devices. The input end of the feedwater pump turbine is provided with a pressure measuring device. The pressure measuring device is a pressure transmitter; the temperature measuring device is a thermocouple or a thermal resistor.

2. A feedwater pump turbine performance monitoring system according to claim 1, characterized in that: The first heater, the second heater and the third heater are all high-voltage heaters.

3. A feedwater pump turbine performance monitoring system according to claim 1, characterized in that: The differential pressure measuring device is a differential pressure transmitter.

4. A monitoring method for a feedwater pump turbine performance monitoring system according to any one of claims 1 to 3, characterized in that: The steps include: Step 1: Select the base case The benchmark operating condition is the performance assessment test results of the newly commissioned feedwater pump steam turbine unit or the performance acceptance test data of the modified feedwater pump steam turbine unit; Specific data involves unit load, main steam flow, reheat steam flow on reheat pipe, extraction pressure and extraction temperature of three-section pipe, extraction pressure and extraction temperature of four-section pipe, steam flow from four-section pipe to deaerator, steam flow from four-section extraction to feedwater pump turbine, exhaust pressure and exhaust flow of intermediate pressure cylinder. The above data are used as the reference library for subsequent steps. Step 2: Calculate the actual operating condition feedwater pump turbine steam inlet flow Step 2.1: Specifically, the condensate flow rate at the input end of the condensate pipe and the main steam pressure and temperature at the output end are detected by means of a pressure measuring device, a temperature measuring device and a differential pressure measuring device, the first extraction pressure and the first extraction temperature on the first pipe, the second extraction pressure and the second extraction temperature on the second pipe, the reheat steam pressure and the reheat steam temperature on the reheat pipe, the third extraction pressure and the third extraction temperature on the third pipe, the fourth extraction pressure and the fourth extraction temperature on the fourth pipe, the fifth extraction pressure and the fifth extraction temperature on the flow from the fourth extraction to the middle discharge section, the exhaust pressure of the feedwater pump turbine, the condensate pressure entering the deaerator, the condensate temperature entering the deaerator, the condensate flow rate entering the deaerator, the inlet temperature, the outlet temperature and the drain temperature of the first heater, the outlet temperature and the drain temperature of the second heater, the outlet temperature and the drain temperature of the third heater, and the reheat desuperheating water flow rate of the reheat desuperheating water pipe; The following data under actual working conditions are obtained by using the heat balance method: main steam flow, reheat steam flow on the reheat pipe, extraction steam flow of the first pipe, extraction steam flow of the second pipe, extraction steam flow of the third pipe, steam flow from the fourth pipe to the deaerator; Step 2.2: The data in the benchmark database are all known numbers. Since the flow area after the four-section pipeline is extracted does not change, and the steam flow rate does not change, the steam flow rate from the four-section extraction to the middle section is calculated using the formula; Step 2.3: Taking the high-pressure cylinder as the research object, calculate the steam inlet flow rate of the intermediate-pressure cylinder according to the law of conservation of mass; Step 2.4: Taking the intermediate pressure cylinder as the research object, calculate the steam inlet flow rate of the feedwater pump turbine according to the law of conservation of mass; Step 3: Calculate the feedwater pump turbine operating efficiency under actual operating conditions.

5. The monitoring method of a feedwater pump turbine performance monitoring system according to claim 4, characterized in that: The steam flow rate G after the fourth extraction to the middle section 中1 The calculation is done using the following formula: Steam flow from the fourth extraction to the middle section: In the above formula: subscript 0 is the reference working condition, subscript 1 is the actual working condition; G 中 It is the steam flow rate from the fourth extraction to the middle discharge section; P4 is the steam pressure of the four-section pipeline; P5 is the exhaust pressure of the intermediate pressure cylinder; T4 is the steam extraction temperature of the four-section pipeline.

6. The monitoring method of a feedwater pump turbine performance monitoring system according to claim 4, characterized in that: The steam inlet flow rate G of the intermediate pressure cylinder 热1 The calculation is performed using the following formula: G 热1 =G 高1 +G 再1 In the above formula: G 热1 is the steam inlet flow rate of the intermediate pressure cylinder; G 高1 is the exhaust flow of high pressure cylinder, G 高1 =G 主1 -G 11 -G 21 (Where: G 主1 is the main steam flow, G 11 is the steam extraction flow rate of a section of pipeline, G 12 is the steam extraction flow rate of the second-stage pipeline); G 再1 It is the reheating and desuperheating water flow rate.

7. The monitoring method of a feedwater pump turbine performance monitoring system according to claim 4, characterized in that: The steam inlet flow rate G of the water pump turbine 小1 The calculation is performed using the following formula: G 小1 =G 热1 -G 31 -G 中1 -G 除1 In the above formula: subscript 1 refers to the actual working condition; G 小1 is the steam inlet flow rate of the feedwater pump turbine; G 热1 is the steam inlet flow rate of the intermediate pressure cylinder; G 31 is the three-stage extraction steam flow; G 除1 It is the flow rate from the four-stage steam extraction to the deaerator.

8. The monitoring method of a feedwater pump turbine performance monitoring system according to claim 4, characterized in that: The feedwater pump turbine operating efficiency η t The calculation is performed using the following formula: In the above formula: η t is the feedwater pump turbine efficiency; P a is the feedwater pump shaft power; h 1t is the steam inlet enthalpy of the feedwater pump turbine; h 2t is the ideal exhaust enthalpy of the feedwater pump turbine.

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