Intelligent monitoring method for oil temperature control loop of steam turbine EH system

Abstract

A steam turbine EH system oil temperature control loop intelligent monitoring method relates to the monitoring field. According to an existing oil cooler monitoring mode, it is difficult to accurately judge whether the performance of an oil cooler is reduced or the cooling effect is abnormal due to micro water leakage. The intelligent terminal calculates the oil temperature variation of each oil cooler and the water temperature variation of each oil cooler according to the oil temperature at the inlet and outlet of each oil cooler oil pipe and the water temperature at the inlet and outlet of each oil cooler water pipe which are collected in real time, and the oil temperature variation and the water temperature variation serve as two measured values of each oil cooler; whether the ratio of the product of the two measured values of each oil cooler to the product of two preset reference values is smaller than a preset value or not is judged, and therefore the performance of the corresponding oil cooler is judged; the intelligent terminal obtains two corresponding coefficients from the corresponding relation table according to the water content of the oil in the inlet and outlet of the oil pipe of each oil cooler and the pressure of each circulation loop collected in real time, whether the product of the two coefficients is larger than or equal to a second threshold value or not is judged, and therefore whether the corresponding oil cooler leaks water or not is judged. The method is used for monitoring faults of the oil cooler.

Description

Technical Field

[0001] This invention relates to the field of monitoring. Background Technology

[0002] The oil temperature in the turbine's EH (Exhaust Heater) system is crucial for ensuring the normal operation of system components such as pumps and valves; therefore, controllable oil temperature is essential for system operation. The oil temperature control loop is located on the EH oil supply unit and serves as one of its bypasses. This loop regulates the oil temperature within the EH oil tank, providing a suitable working medium for the normal operation of the EH system. The oil temperature control loop primarily consists of a heater, an oil cooler, a temperature sensor, and a control unit.

[0003] Traditional oil temperature control strategies focus on regulating oil temperature by starting and stopping the oil cooler, lacking real-time monitoring of the cooler's own operating status. Over long-term operation, the oil cooler is highly susceptible to heat exchange efficiency degradation (i.e., performance decline) due to scaling on the water side and fouling on the oil side. Currently, effective online monitoring methods are generally lacking, and issues are often only detected during obvious oil temperature control anomalies or routine maintenance. By this time, performance degradation may have already become significant, affecting system temperature control accuracy and energy consumption. Existing monitoring methods (such as simply monitoring the inlet and outlet oil temperatures of the oil cooler and comparing them to preset thresholds) consider only a single parameter and are easily affected by fluctuations in operating conditions. When abnormal oil temperature occurs, these methods struggle to accurately determine whether insufficient heat exchange is due to cooler performance degradation or minor water leakage causing abnormal cooling, hindering operators from quickly locating the root cause and taking targeted measures. This constitutes a potential hazard to the safe and stable operation of the EF system. Summary of the Invention

[0004] The purpose of this invention is to address the problem that existing methods of monitoring oil coolers are difficult to accurately determine whether insufficient heat exchange is caused by a decline in oil cooler performance or by a minor water leak causing abnormal cooling effect, which is not conducive to operators quickly locating the root cause of the fault and taking targeted measures. Therefore, an intelligent monitoring method for the oil temperature control loop of the turbine EH system is proposed.

[0005] A smart monitoring method for the oil temperature control loop of a steam turbine EH system, the method being used to monitor oil cooler malfunctions, the method comprising the following:

[0006] There are two ways to monitor whether the oil cooler is functioning properly. The first way is:

[0007] The intelligent terminal calculates the oil temperature change and water temperature change of each oil cooler based on the real-time collected oil temperature at the inlet and outlet of each oil pipe and the water temperature at the inlet and outlet of each water pipe. The oil temperature change and water temperature change of each oil cooler are used as two measured values ​​for each oil cooler. The terminal then determines whether the ratio of the product of the two measured values ​​of each oil cooler to the product of two preset benchmark values ​​is less than a preset value. If the ratio is greater, the corresponding oil cooler is judged to have degraded performance; otherwise, the corresponding oil cooler is judged to have normal performance.

[0008] The second method is:

[0009] The intelligent terminal calculates the oil temperature change and water temperature change of each oil cooler based on the real-time collected oil temperature at the inlet and outlet of each oil pipe and the water temperature at the inlet and outlet of each water pipe. The intelligent terminal obtains the oil temperature coefficient corresponding to the oil temperature change of each oil cooler from a preset oil temperature change range and oil temperature coefficient relationship table, and obtains the water temperature coefficient corresponding to the water temperature change of each oil cooler from a preset water temperature change range and water temperature coefficient relationship table. It then determines whether the product of the two coefficients is greater than or equal to a first threshold. If it is, it determines that the performance of the corresponding oil cooler has decreased; otherwise, it determines that the performance of the corresponding oil cooler is normal.

[0010] Methods for monitoring whether the oil cooler is leaking:

[0011] The intelligent terminal calculates the difference in water content in the oil of each cooler's oil pipe based on the real-time collected water content in the oil inlet and outlet of each cooler. The intelligent terminal obtains the water content coefficient corresponding to the difference in water content in the oil of each cooler from a preset table of water content difference range and water content coefficient relationship. It also obtains the pressure coefficient corresponding to the real-time collected pressure of each circulation loop from a preset table of pressure range and pressure coefficient relationship. The terminal determines whether the product of the two coefficients is greater than or equal to a second threshold. If it is, the corresponding cooler is determined to be leaking water; otherwise, the corresponding cooler is determined to be working normally.

[0012] Preferably, the method further includes monitoring the operation of the heater or oil cooler, specifically as follows:

[0013] The intelligent terminal calculates the change in average tank temperature between two adjacent moments based on the real-time collected average tank temperature. It obtains the temperature change coefficient corresponding to the change in average tank temperature from a preset table of relationships between the range of tank temperature changes and the temperature change coefficient. It also obtains the average temperature coefficient corresponding to the real-time collected average tank temperature from a preset table of relationships between the average temperature range and the average temperature coefficient. The product of these two coefficients is compared with n preset ranges to control the heater or oil cooler to work.

[0014] Preferably, the product of the two values ​​is compared with n preset ranges to control the operation of the heater or oil cooler, specifically as follows:

[0015] The preset n ranges are, in order, the first interval, the second interval, the third interval, the fourth interval, the fifth interval, and the sixth interval;

[0016] When the product of the two values ​​is in the first interval, the heater is activated and an alarm signal is issued;

[0017] When the product of these two values ​​is in the second interval, the heater is activated;

[0018] When the product of these two values ​​is in the third interval, neither the heater nor the single oil cooler will operate.

[0019] When the product of these two values ​​is in the fourth interval, start the single oil cooler;

[0020] When the product of these two values ​​is in the fifth interval, activate the dual oil cooler;

[0021] When the product of the two values ​​is in the sixth interval, the dual oil cooler is activated and an alarm signal is issued.

[0022] Preferably, the method further includes monitoring heater malfunctions, specifically as follows:

[0023] The intelligent terminal determines whether the ratio of the average temperature of the fuel tank collected to the average temperature of the fuel tank collected at a preset time is less than a third threshold. If it is, the heater is determined to be faulty; otherwise, the heater is determined to be normal.

[0024] Preferably, the method further includes monitoring whether the oil quality inside the heater is normal, the specific process being:

[0025] The intelligent terminal obtains the oil quality coefficient corresponding to the change in oil quality measurement value of each circulation return port from the preset oil quality measurement value change range and oil quality coefficient relationship table, and obtains the pressure coefficient corresponding to the pressure of each circulation loop from the preset pressure range and pressure coefficient relationship table. It then determines whether the product of the two coefficients is greater than or equal to the fourth threshold. If it is, it determines that the oil quality in the heater is poor; otherwise, it determines that the oil quality in the heater is normal.

[0026] The beneficial effects of this invention are:

[0027] This invention can monitor key parameters of the oil temperature control loop in the EH oil supply unit to determine whether oil cooler failure or water leakage has occurred. This invention monitors the oil cooler based on the inlet and outlet oil temperatures of each oil pipe and the inlet and outlet water temperatures of each water pipe. Compared to existing monitoring methods, it considers a wider range of parameters and offers higher monitoring accuracy. Therefore, this invention can promptly identify cooling system faults, ensuring the safe and stable operation of the entire EH system. Attached Figure Description

[0028] Figure 1Diagram showing the oil temperature control loop and sensor layout of the steam turbine EH system;

[0029] Figure 2 A flowchart for controlling the operation of a heater or oil cooler;

[0030] Figure 3 Flowchart for oil cooler performance diagnosis;

[0031] Figure 4 Here is a flowchart for heater fault diagnosis;

[0032] Figure 5 This is a flowchart of the overall monitoring process. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0035] Example:

[0036] A smart monitoring method for the oil temperature control loop of a steam turbine EH system, the method being used to monitor oil cooler malfunctions, the method comprising the following:

[0037] There are two ways to monitor whether the oil cooler is functioning properly. The first way is:

[0038] The intelligent terminal calculates the oil temperature change and water temperature change of each oil cooler based on the real-time collected oil temperature at the inlet and outlet of each oil pipe and the water temperature at the inlet and outlet of each water pipe. The oil temperature change and water temperature change of each oil cooler are used as two measured values ​​for each oil cooler. The terminal then determines whether the ratio of the product of the two measured values ​​of each oil cooler to the product of two preset benchmark values ​​is less than a preset value. If the ratio is greater, the corresponding oil cooler is judged to have degraded performance; otherwise, the corresponding oil cooler is judged to have normal performance.

[0039] The second method is:

[0040] The intelligent terminal calculates the oil temperature change and water temperature change of each oil cooler based on the real-time collected oil temperature at the inlet and outlet of each oil pipe and the water temperature at the inlet and outlet of each water pipe. The intelligent terminal obtains the oil temperature coefficient corresponding to the oil temperature change of each oil cooler from a preset oil temperature change range and oil temperature coefficient relationship table, and obtains the water temperature coefficient corresponding to the water temperature change of each oil cooler from a preset water temperature change range and water temperature coefficient relationship table. It then determines whether the product of the two coefficients is greater than or equal to a first threshold. If it is, it determines that the performance of the corresponding oil cooler has decreased; otherwise, it determines that the performance of the corresponding oil cooler is normal.

[0041] Methods for monitoring whether the oil cooler is leaking:

[0042] The intelligent terminal calculates the difference in water content in the oil of each cooler's oil pipe based on the real-time collected water content in the oil inlet and outlet of each cooler. The intelligent terminal obtains the water content coefficient corresponding to the difference in water content in the oil of each cooler from a preset table of water content difference range and water content coefficient relationship. It also obtains the pressure coefficient corresponding to the real-time collected pressure of each circulation loop from a preset table of pressure range and pressure coefficient relationship. The terminal determines whether the product of the two coefficients is greater than or equal to a second threshold. If it is, the corresponding cooler is determined to be leaking water; otherwise, the corresponding cooler is determined to be working normally.

[0043] Specifically, pressure sensors, temperature sensors, and oil quality monitoring devices are added to the conventional EH system oil temperature control loop, along with an independent intelligent front-end to achieve control and monitoring functions. The EH oil supply unit's oil temperature control loop is equipped with inlet and outlet oil and water temperature measuring points, and pressure transmitters are installed at the outlet of each pump group to monitor the channel's operation in real time. Additionally, at least three temperature-measuring thermal resistors are symmetrically positioned within the oil tank to obtain the average temperature of the tank.

[0044] Table 1 shows the parameter information for each device code and the specific measured values, constants, and calculated values ​​of the sensors used.

[0045] Table 1. Details of measuring points and other constant physical quantities in the intelligent control method of the EH system oil supply unit.

[0046]

[0047] When the EH system is working, the oil temperature may rise or fall depending on the environment and operating conditions. The system temperature can be determined by taking the average value of three measuring points placed in the oil tank.

[0048] In the oil temperature control loop, the performance of the oil cooler deteriorates over long-term use due to scale buildup and oil accumulation. Therefore, performance diagnosis of the oil cooling effect is necessary. Since the performance of the circulating pump, as an oil pump, is relatively fixed, especially its volumetric efficiency, the water-side cooling effect is crucial. Monitoring the oil cooler by observing changes in its inlet and outlet temperatures during operation—specifically, the trend of decreasing water temperature and increasing oil temperature—can determine the cooler's operating status. Specifically, the following conditions should be considered (taking oil cooler 1 as an example):

[0049] The system records the current temperature changes on the water and oil sides every time the continuous running time t reaches 10 minutes. The water side temperature rise is... The oil side temperature decreased to The system records the temperature rise after the most recent oil cooler replacement. The latest measured water-side temperature rise in the system The oil temperature dropped to [value] after the last oil cooler replacement. The latest measured oil-side temperature drop in the system When it appears ) / This indicates a deterioration in the performance of the oil cooler, triggering an alarm signal. When ) / If the temperature rises and P1 increases, the system oil cooler must be replaced.

[0050] set up All are fuzzy logic variables, fuzzy logic functions , where logical variables The coefficients are shown in Table 2, which is also a table showing the relationship between the preset water temperature change range and the water temperature coefficient. The values ​​are shown in Figure 3. Figure 3 It is also a table showing the relationship between the preset range of oil temperature change and the oil temperature coefficient.

[0051] Table 2 Logical Variables coefficient

[0052]

[0053] Table 3 Logical Variables coefficient

[0054]

[0055] Therefore The truth table is shown in Table 4, which is the coefficient corresponding to the change in oil temperature multiplied by the coefficient corresponding to the change in water temperature.

[0056] Table 4 truth table

[0057] when This indicates a decline in the performance of the oil cooler, triggering an alarm signal. At this time, the system outputs... ,when This indicates that the oil cooler is working properly, and the system output at this time... Meanwhile, a dangerous and common problem in the system is cooler leakage. Regardless of whether the cooler is running or not, if the following situation occurs, it proves that the cooler is leaking (taking oil cooler 1 as an example). At this time, an alarm signal needs to be triggered and manual intervention should be requested for inspection.

[0058] 100ppm;

[0059] set up All are fuzzy logic variables, fuzzy logic functions , where logical variables The values ​​are shown in Table 5. Table 5 is also a table showing the relationship between the preset range of moisture content difference and the moisture content coefficient. The values ​​are shown in Table 6, which is also a table showing the relationship between the preset pressure range and the coefficient.

[0060] Table 5 Logical Variables coefficient

[0061]

[0062] Table 6 Logical Variable Temperature Rise coefficient

[0063]

[0064] Therefore The truth table is shown in Table 7, which is the coefficient corresponding to the difference in water content in the oil at the inlet and outlet of each condenser multiplied by the coefficient corresponding to the pressure of each circulation loop.

[0065] Table 7 truth table

[0066]

[0067] The logic block diagram of the oil cooler performance diagnostic process is attached. Figure 3 As shown. When This indicates that the oil cooler is leaking water, triggering an alarm signal. At this time, the system outputs... ,when This indicates that the oil cooler is working properly, and the system output at this time... .

[0068] Furthermore, the method also includes monitoring the operation of the heater or oil cooler, specifically as follows:

[0069] The intelligent terminal calculates the change in average tank temperature between two adjacent moments based on the real-time collected average tank temperature. It obtains the temperature change coefficient corresponding to the change in average tank temperature from a preset table of relationships between the range of tank temperature changes and the temperature change coefficient. It also obtains the average temperature coefficient corresponding to the real-time collected average tank temperature from a preset table of relationships between the average temperature range and the average temperature coefficient. The product of these two coefficients is compared with n preset ranges to control the heater or oil cooler to work.

[0070] Further specifying the parameters, the product of these two values ​​is compared with n preset ranges to control the operation of the heater or oil cooler, specifically:

[0071] The preset n ranges are, in order, the first interval, the second interval, the third interval, the fourth interval, the fifth interval, and the sixth interval;

[0072] When the product of the two values ​​is in the first interval, the heater is activated and an alarm signal is issued;

[0073] When the product of these two values ​​is in the second interval, the heater is activated;

[0074] When the product of these two values ​​is in the third interval, neither the heater nor the single oil cooler will operate.

[0075] When the product of these two values ​​is in the fourth interval, start the single oil cooler;

[0076] When the product of these two values ​​is in the fifth interval, activate the dual oil cooler;

[0077] When the product of the two values ​​is in the sixth interval, the dual oil cooler is activated and an alarm signal is issued.

[0078] Furthermore, the method also includes monitoring heater malfunctions, specifically as follows:

[0079] The intelligent terminal determines whether the ratio of the average temperature of the fuel tank collected to the average temperature of the fuel tank collected at a preset time is less than a third threshold. If it is, the heater is determined to be faulty; otherwise, the heater is determined to be normal.

[0080] Specifically, for the EH system's commonly used plunger pump with No. 46 oil, the required oil temperature control is 45±5℃, i.e., between 40-50℃. Conventional temperature control systems use a temperature controller to activate cooling or heating when the average temperature is detected to be high or low. This embodiment uses fuzzy control to fuzzify and discretize the collected values. The cooling circuit, according to instructions, maintains the operation of oil cooler No. 1, maintains parallel operation of oil coolers No. 1 and No. 2, or maintains parallel operation of both oil coolers while simultaneously triggering an alarm and requesting manual intervention. The heating circuit, according to instructions, maintains the operation of the heater, or maintains operation while simultaneously triggering an alarm and requesting manual intervention. The specific logic relationship for the fuzzification and discretization of the values ​​is as follows.

[0081] average oil temperature ,when ℃ or At ℃, the system records the temperature rise within 5 minutes in the database. The verification is then performed. At this time, the cold oil / heating start logic is executed according to the logic relationship in Table 7. Table 7 is a table showing the relationship between the preset average temperature range and the coefficient.

[0082] set up All are fuzzy logic variables, fuzzy logic functions logical variables The values ​​are shown in Table 8, temperature rise The values ​​are shown in Figure 9, and Table 8 is a table showing the relationship between the preset temperature change range and the coefficient.

[0083] Table 8 Logical Variables numerical value

[0084] Table 9 Logical Variable Temperature Rise numerical value

[0085] Therefore The truth table is shown in Table 10, that is... and The product is shown in Table 9.

[0086] Table 10 truth table

[0087]

[0088] Will and The product is compared with n preset ranges. The process for controlling the operation of the heater or oil cooler is shown in the appendix. Figure 2 As shown.

[0089] Furthermore, the method also includes monitoring heater malfunctions, specifically as follows:

[0090] The intelligent terminal determines whether the ratio of the average temperature of the fuel tank collected to the average temperature of the fuel tank collected at a preset time is less than a third threshold. If it is, the heater is determined to be faulty; otherwise, the heater is determined to be normal.

[0091] Furthermore, the method also includes monitoring whether the oil quality inside the heater is normal, the specific process of which is as follows:

[0092] The intelligent terminal obtains the oil quality coefficient corresponding to the change in oil quality measurement value of each circulation return port from the preset oil quality measurement value change range and oil quality coefficient relationship table, and obtains the pressure coefficient corresponding to the pressure of each circulation loop from the preset pressure range and pressure coefficient relationship table. It then determines whether the product of the two coefficients is greater than or equal to the fourth threshold. If it is, it determines that the oil quality in the heater is poor; otherwise, it determines that the oil quality in the heater is normal.

[0093] Specifically, heating module malfunctions can manifest in two ways: either the temperature rise is affected, or the temperature rise causes oil quality deterioration. Therefore, monitoring includes addressing both abnormalities in the average oil temperature change rate and abnormal oil quality monitoring. The diagnosis of heating circuit problems involves recording the temperature rise over 10 minutes when the oil tank is heated. The heating oil level measured after the system's latest heater replacement was [value missing]. The latest measured heating oil liter in the system When it appears / When this occurs, it indicates a problem with the heating circuit and triggers an alarm signal. / If this occurs, the heater needs to be replaced. An abnormal oil quality monitoring result is a change in system particle size after the heating circuit has been operating for more than 30 minutes. According to oil quality standards, an oil quality degradation level of 1 indicates system deterioration.

[0094] That is, it appeared If P1 or P2 increases simultaneously, it indicates that the heater is experiencing localized overheating, requiring an alarm and manual intervention for inspection.

[0095] set up All are fuzzy logic variables, fuzzy logic functions , where logical variables The values ​​are shown in Table 11. Table 11 is also a preset table showing the relationship between the range of changes in oil quality measurement values ​​and the coefficients. The values ​​are shown in Table 12, which is also a table showing the relationship between the preset pressure range and the coefficient.

[0096] Table 11 Logical Variables numerical value

[0097]

[0098] Table 12 Logical Variable Temperature Rise numerical value

[0099]

[0100] Therefore The truth table is shown in Table 13, which is the value corresponding to the change in oil quality measurement value at each circulation return port multiplied by the coefficient corresponding to the pressure of each circulation loop.

[0101] Table 13 truth table

[0102]

[0103] when This indicates that the oil quality has deteriorated, triggering an alarm signal. At this time, the system outputs... ,when This indicates that the oil quality is normal, and the system outputs at this time. ;

[0104] The logic block diagram of the heating circuit performance diagnosis process is attached. Figure 4 As shown. When / When this occurs, it indicates a problem with the heater, triggering an alarm signal. At this time, the system outputs... , / This indicates that the heater is working properly, and the system output at this time... .

[0105] When the system is running, the product of all the above system values ​​can be used to determine the system's current operating state, as shown in Table 14. The flowchart of the system diagnosis and handling loop is attached. Figure 5 As shown, the probability of the system experiencing all three faults simultaneously is relatively small, and they will not be discussed here.

[0106] Table 14 System Calculation Values ​​and System Operating Status

[0107]

[0108] according to Figure 5 This inspection process enables fault diagnosis of the entire oil temperature control loop in the EH system and determines whether the oil quality has deteriorated. It also provides timely reminders to replace equipment on-site, thus facilitating the prompt handling of various faults in the oil temperature control loop.

[0109] In this embodiment, the control process and the collected data and diagnostic information can be sent to the backend intelligent terminal for comprehensive analysis. Combined with other information such as the operating status of each oil-using device in the system, system flow rate, system pressure, etc., the operating status of the EH system can be further determined, thereby achieving comprehensive fault diagnosis of the entire system. Manual fault diagnosis can also be performed by combining other operating parameters.

[0110] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A method for intelligent monitoring of oil temperature control loop in a steam turbine EH system, characterized in that, The monitoring method is used to monitor oil cooler malfunctions, and the method includes the following: There are two ways to monitor whether the oil cooler is functioning properly. The first way is: The intelligent terminal calculates the oil temperature change and water temperature change of each oil cooler based on the real-time collected oil temperature at the inlet and outlet of each oil pipe and the water temperature at the inlet and outlet of each water pipe. The oil temperature change and water temperature change of each oil cooler are used as two measured values ​​for each oil cooler. The terminal then determines whether the ratio of the product of the two measured values ​​of each oil cooler to the product of two preset benchmark values ​​is less than a preset value. If the ratio is greater, the corresponding oil cooler is judged to have degraded performance; otherwise, the corresponding oil cooler is judged to have normal performance. The second method is: The intelligent terminal calculates the oil temperature change and water temperature change of each oil cooler based on the real-time collected oil temperature at the inlet and outlet of each oil pipe and the water temperature at the inlet and outlet of each water pipe. The intelligent terminal obtains the oil temperature coefficient corresponding to the oil temperature change of each oil cooler from a preset oil temperature change range and oil temperature coefficient relationship table, and obtains the water temperature coefficient corresponding to the water temperature change of each oil cooler from a preset water temperature change range and water temperature coefficient relationship table. It then determines whether the product of the two coefficients is greater than or equal to a first threshold. If it is, it determines that the performance of the corresponding oil cooler has decreased; otherwise, it determines that the performance of the corresponding oil cooler is normal. Methods for monitoring whether the oil cooler is leaking: The intelligent terminal calculates the difference in water content in the oil of each cooler's oil pipe based on the real-time collected water content in the oil inlet and outlet of each cooler. The intelligent terminal obtains the water content coefficient corresponding to the difference in water content in the oil of each cooler from a preset table of water content difference range and water content coefficient relationship. It also obtains the pressure coefficient corresponding to the real-time collected pressure of each circulation loop from a preset table of pressure range and pressure coefficient relationship. The terminal determines whether the product of the two coefficients is greater than or equal to a second threshold. If it is, the corresponding cooler is determined to be leaking water; otherwise, the corresponding cooler is determined to be working normally.

2. The intelligent monitoring method for the oil temperature control loop of the steam turbine EH system according to claim 1, characterized in that, The method also includes monitoring the operation of the heater or oil cooler, the specific process of which is as follows: The intelligent terminal calculates the change in average tank temperature between two adjacent moments based on the real-time collected average tank temperature. It obtains the temperature change coefficient corresponding to the change in average tank temperature from a preset table of relationships between the range of tank temperature changes and the temperature change coefficient. It also obtains the average temperature coefficient corresponding to the real-time collected average tank temperature from a preset table of relationships between the average temperature range and the average temperature coefficient. The product of these two coefficients is compared with n preset ranges to control the heater or oil cooler to work.

3. The intelligent monitoring method for the oil temperature control loop of the steam turbine EH system according to claim 2, characterized in that, The product of these two values ​​is compared with n preset ranges to control the operation of the heater or oil cooler, specifically: The preset n ranges are, in order, the first interval, the second interval, the third interval, the fourth interval, the fifth interval, and the sixth interval; When the product of the two values ​​is in the first interval, the heater is activated and an alarm signal is issued; When the product of these two values ​​is in the second interval, the heater is activated; When the product of these two values ​​is in the third interval, neither the heater nor the single oil cooler will operate. When the product of these two values ​​is in the fourth interval, start the single oil cooler; When the product of these two values ​​is in the fifth interval, activate the dual oil cooler; When the product of the two values ​​is in the sixth interval, the dual oil cooler is activated and an alarm signal is issued.

4. The intelligent monitoring method for the oil temperature control loop of the steam turbine EH system according to claim 1, characterized in that, The method also includes monitoring heater malfunctions, the specific process of which is as follows: The intelligent terminal determines whether the ratio of the average temperature of the fuel tank collected to the average temperature of the fuel tank collected at a preset time is less than a third threshold. If it is, the heater is determined to be faulty; otherwise, the heater is determined to be normal.

5. The intelligent monitoring method for the oil temperature control loop of the steam turbine EH system according to claim 4, characterized in that, The method also includes monitoring whether the oil quality inside the heater is normal, the specific process is as follows: The intelligent terminal obtains the oil quality coefficient corresponding to the change in oil quality measurement value of each circulation return port from the preset oil quality measurement value change range and oil quality coefficient relationship table, and obtains the pressure coefficient corresponding to the pressure of each circulation loop from the preset pressure range and pressure coefficient relationship table. It then determines whether the product of the two coefficients is greater than or equal to the fourth threshold. If it is, it determines that the oil quality in the heater is poor; otherwise, it determines that the oil quality in the heater is normal.

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