A performance monitoring system and method for forced air cooling fans of a power cabinet of an excitation system

Abstract

This invention discloses a performance monitoring system and method for forced air-cooled power cabinet cooling fans in excitation systems. The system includes an air guide and a processing controller installed within the power cabinet's cooling duct. The air guide includes a pressure plate, a pressure plate baffle, a cylindrical strain gauge, and a limit switch. During monitoring: after the fan starts, if the pressure plate opens under wind force and triggers the limit switch, the fan is considered to be starting normally. Simultaneously, the pressure plate's opening is limited by the baffle, and under continuous wind force, the baffle is compressed, causing the strain gauge to deform and output real-time strain force data. The processing controller compares this data with a preset alarm threshold (based on rated wind pressure). If the data is less than the threshold, an anomaly is determined, and an early warning is triggered. This invention combines qualitative start-stop monitoring with quantitative wind force monitoring, enabling accurate early warning in the early stages of fan performance degradation. This shifts from reactive maintenance to preventative maintenance, ensuring the safe operation of the generator set.

Description

Technical Field

[0001] This invention relates to the field of power generation equipment operation status monitoring and maintenance technology, specifically to a system and method for monitoring the performance of a forced air-cooled power cabinet cooling fan in an excitation system. Background Technology

[0002] The statements in this section are provided only as background information in relation to this disclosure and may not constitute prior art.

[0003] Currently, the excitation system power cabinets of large and medium-sized hydropower stations generally use forced air cooling for heat dissipation. The working process is usually as follows: after the fan starts, the generated air pressure blows open the air pressure cover (usually a lightweight flap or cover) at the inlet of the rectifier channel of the power cabinet. Cold air enters from the air inlet filter at the bottom of the cabinet, flows through the thyristor rectifier and its heat sink, undergoes heat exchange, and is then discharged as hot air from the top of the cabinet, thereby achieving efficient heat dissipation of the power components.

[0004] As the core power source of this cooling system, the performance of the fan directly affects the heat dissipation effect. With the accumulation of operating time, problems such as fan bearing wear, blade dust accumulation, and motor aging will cause the fan performance to gradually decline, which will manifest as a decrease in output air pressure and air volume. In addition, if there is too much dust accumulation on the air inlet filter, it will also lead to a decrease in the actual air pressure in the system.

[0005] However, existing technologies generally lack effective monitoring methods for wind turbine operating performance and actual wind speed reduction. Problems are typically only detected when the wind pressure drops so low that it cannot open the pressure plate, or when power components overheat and trigger alarms due to insufficient heat dissipation. By this time, the wind turbine may have already failed completely, or thermal damage may have occurred to the power equipment. This monitoring method is essentially "reactive maintenance," severely lacking in predictability. Due to factors such as equipment performance degradation or external ventilation, the wind pressure generated by the wind turbine may only be enough to barely open the pressure plate, but the cooling airflow has already decreased significantly, posing a substantial safety hazard. Furthermore, if all the fans in the power cabinet malfunction, it can easily lead to the power cabinet being disconnected, seriously affecting the safe and stable operation of the generator.

[0006] Therefore, there is an urgent need for a technical solution that can accurately monitor the actual operating performance of wind turbines and issue early warnings in the early stages of abnormal wind pressure decline. Summary of the Invention

[0007] The purpose of this invention is to address the current lack of effective monitoring methods for the operating performance and airflow degradation of cooling fans in the excitation system power cabinets of large and medium-sized hydropower stations. Currently, relying solely on limit switches only triggers passive alarms when the air pressure is so low that the cover cannot be opened or the power components overheat, which is a form of "reactive maintenance" lacking foresight and easily leading to thermal damage to power equipment or even the removal of the power cabinet. This invention provides a performance monitoring system and method for forced air-cooled power cabinet cooling fans in excitation systems. Based on a guide vane structure that links qualitative monitoring using limit switches with quantitative force measurement using cylindrical ring strain gauges, and combined with an extreme value anti-interference algorithm derived from the minimum initial air pressure value of brand-new fans in the same batch, it achieves accurate real-time monitoring of the actual mechanical output of the fan. Precise warnings can be triggered in the early stages of fan performance degradation before complete failure, completely transforming reactive maintenance into preventative maintenance.

[0008] The technical solution of the present invention is as follows: A method for monitoring the performance of a forced-air-cooled power cabinet cooling fan in an excitation system is based on a monitoring system. The power cabinet contains a fan, and the monitoring system includes an air guide installed within the power cabinet. The air guide includes a pressure plate, a pressure plate baffle, a cylindrical strain gauge fixed to the pressure plate baffle, and a limit switch. The monitoring method includes the following steps: After the fan starts, the operating status of the limit switch is monitored; wherein, the wind pressure plate opens after being subjected to the wind force of the fan, and triggers the limit switch. If the limit switch is detected to be activated, the fan is determined to be operating normally. The opening of the pressure plate is restricted by the pressure plate baffle after it is opened, and the pressure plate baffle is squeezed by the wind force of the fan, causing the cylindrical ring strain gauge to deform and output real-time strain force data. Acquire the real-time strain force data and compare the real-time strain force data with a preset alarm threshold; If the real-time strain data is greater than or equal to the alarm threshold, the wind force of the fan is determined to be normal. If the real-time strain data is less than the alarm threshold, the wind force of the wind turbine is determined to be abnormal and an early warning is triggered.

[0009] Furthermore, the preset alarm threshold is [value missing] of the rated wind pressure. .

[0010] Furthermore, the formula for calculating the rated wind pressure is as follows: ; in, The rated wind pressure, It is the minimum initial wind pressure value of the brand-new fans in the same batch in the monitored excitation system.

[0011] Furthermore, the step of obtaining the minimum value of the initial wind pressure includes: In configuration In the excitation system of the unit with a power cabinet, each power cabinet includes two fans from the same batch, one main and one backup. Obtain the The initial wind pressure values ​​measured when the typhoon generator is in brand new condition are used as the minimum initial wind pressure value. .

[0012] Furthermore, the limit switch adopts a normally open contact; when the air pressure plate is opened and triggers the limit switch, the normally open contact closes to provide feedback that the fan is operating normally.

[0013] This invention also proposes a performance monitoring system for the heat dissipation fan of a forced air-cooled power cabinet in an excitation system, based on the monitoring method described above. The power cabinet is equipped with a fan, and the monitoring system includes: An air guide is installed within the cooling air duct of the power cabinet. The air guide includes a pressure plate, a pressure plate baffle, a cylindrical strain gauge fixed to the pressure plate baffle, and a limit switch. The pressure plate is configured to open upon being subjected to the airflow from the fan, triggering the limit switch. After opening, the pressure plate's opening is limited by the pressure plate baffle, and under the continuous action of the fan's airflow, the pressure plate baffle is compressed, causing the cylindrical strain gauge to deform and output real-time strain force data. The processing controller is communicatively connected to both the cylindrical strain gauge and the limit switch. The processing controller is configured to: monitor the operation status of the limit switch after the fan starts; if the limit switch is detected to be activated, determine that the fan is operating normally and acquire the real-time strain force data; compare the real-time strain force data with a preset alarm threshold; if the real-time strain force data is greater than or equal to the alarm threshold, determine that the fan's wind force is normal; if the real-time strain force data is less than the alarm threshold, determine that the fan's wind force is abnormal and trigger an early warning.

[0014] Furthermore, the cylindrical ring strain gauge is equipped with a secondary signal transmission cable; the secondary signal transmission cable is built into the inside of the wind pressure plate baffle and leads out from the end of the wind pressure plate baffle to the processing controller.

[0015] Furthermore, the air guide is installed directly above the fan.

[0016] Furthermore, when the processing controller determines that the wind force of the fan is abnormal, it is also configured to output the abnormality cause diagnosis result; the abnormality cause diagnosis result includes: abnormality of the fan body, insufficient air intake due to dust accumulation on the air inlet filter, or detection error of the cylindrical ring strain gauge.

[0017] Furthermore, the air inlet filter is provided on the lower side of the power cabinet panel; after the fan is started, external cold air enters the cooling air duct through the air inlet filter to apply wind force to the air pressure plate to open it.

[0018] Compared with existing technologies, the advantages of this invention are: 1. Strong real-time performance and predictability. This invention can monitor the mechanical forces that directly reflect the actual output of the fan in real time. Early warnings can be issued in the early stages of anomalies, when fan performance is just beginning to decline, leading to a decrease in cooling airflow and potential safety hazards, but before complete failure. This provides ample time for planned maintenance, realizing a shift from "reactive maintenance" to "preventive maintenance," effectively avoiding power cabinet shutdown accidents caused by abnormalities in all fans.

[0019] 2. The monitoring results are direct and accurate. The monitored object is the direct mechanical force exerted by the pressure plate on the pressure plate stop bar, which originates directly from the effective output air pressure of the fan. Compared with indirect methods such as monitoring fan current or speed, this scheme effectively avoids systematic errors caused by indirect monitoring, and the results are accurate and reliable.

[0020] 3. Innovative and rigorous anti-false alarm algorithm. It introduces... The rated wind pressure calculation formula and threshold comparison logic cleverly solve the inherent technical contradiction of "both to provide timely alarms in the early stages of performance degradation and to absolutely prevent false alarms when new wind turbines are put into operation".

[0021] 4. Simple structure and easy to modify. It only requires integrating strain detection elements into the existing limit bar and cleverly embedding the secondary cable inside the bar for protection and electromagnetic shielding. No major changes are needed to the core structure of the power cabinet, resulting in low implementation cost and easy promotion on existing units.

[0022] 5. High system reliability. The strain detection technology is mature, the sensor structure is simple and has no additional moving parts, and it has a long service life, making it extremely suitable for long-term stable operation in the complex electromagnetic and high-vibration environment of hydropower stations. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in the embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0024] Figure 1 This is a schematic diagram of the overall structure and configuration of the air guide provided in an embodiment of the present invention; Figure 2 A block diagram illustrating the monitoring principle of existing air guides and fans that do not incorporate strain monitoring; Figure 3 This is a block diagram illustrating the principle of fan monitoring and anomaly diagnosis after adding strain gauges, as provided in an embodiment of the present invention.

[0025] Reference numerals in the attached diagram: 1-Air pressure plate; 2-Air pressure plate baffle; 3-Cylindrical ring strain gauge; 4-Limit switch; 5-Cooling air duct. Detailed Implementation

[0026] It should be noted that the terminology " First ” and " second ” Relational terms like "etc." are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any actual relationship or order between these entities or operations. Furthermore, the term... " include ” , " Include ” Or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, the statement... " Including one ……” The definition of a specific element does not preclude the presence of other identical elements in a process, method, article, or apparatus that includes the element.

[0027] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0028] Example 1 This embodiment provides a method and system for monitoring the performance of a forced-air-cooled power cabinet cooling fan in an excitation system. Please refer to [link / reference]. Figures 1 to 3 The specific technical details of this embodiment will be analyzed in detail.

[0029] Before elaborating on this monitoring method, we will first explain the hardware architecture and application background upon which it relies. Currently, the excitation system power cabinets of large and medium-sized hydropower stations generally use forced air cooling for heat dissipation. As is known to those skilled in the art, the fan, as the core power source of this cooling system, operates as follows: after the fan starts, the generated cold air enters through the air inlet filter at the bottom of the cabinet side, flows through the thyristor rectifier and its heat sink for heat exchange, and is then discharged as hot air from the top of the cabinet, thereby achieving efficient heat dissipation for the power components.

[0030] To implement the aforementioned performance monitoring method, this embodiment constructs a performance monitoring system for the cooling fan of a forced-air-cooled power cabinet in an excitation system. A fan is installed inside the power cabinet, and the monitoring system includes an air guide installed inside the power cabinet (specifically within the cooling air duct 5 of the power cabinet). The air guide is generally installed directly above the forced-air-cooled fan of the excitation power cabinet. Figure 1 (Schematic diagram of the overall structure of the air guide) As shown, the air guide mainly consists of four parts: air pressure plate 1, air pressure plate baffle 2, cylindrical ring strain gauge 3 fixed on the air pressure plate baffle 2, and limit switch 4.

[0031] Specifically, the wind pressure plate 1 is generally a lightweight flap or cover plate, installed at the inlet of the rectifier channel of the power cabinet, configured to open upon being subjected to the wind force of the fan. Due to the high wind pressure inside the excitation power cabinet, the cylindrical ring strain gauge 3 can more evenly and stably withstand the radial compressive force. Furthermore, to adapt to the complex electromagnetic and vibration environment of the power station, the cylindrical ring strain gauge 3 is equipped with a secondary signal transmission cable. The secondary signal transmission cable is built into the wind pressure plate baffle 2 and leads out from the end of the wind pressure plate baffle 2 to the processing controller. This ingenious design of building the cable inside not only protects the cable from physical damage caused by strong winds but also provides natural electromagnetic shielding, ensuring the accuracy of the transmission of weak strain electrical signals. The processing controller is communicatively connected to the cylindrical ring strain gauge 3 and the limit switch 4, respectively, for executing core logic decisions.

[0032] like Figure 2 As shown in the existing wind turbine monitoring principle diagram, the existing wind deflector without strain monitoring can only achieve the following: after the wind turbine starts, the pressure plate 1 opens, triggering the limit switch 4 to act. After the system detects the action, it determines that the wind turbine is starting normally, but does not monitor whether the wind turbine pressure is reduced.

[0033] To overcome the above-mentioned defects, such as Figure 3 (Diagram of fan monitoring principle with strain gauges) As shown, based on the above monitoring system, the method for monitoring the performance of the forced air-cooled power cabinet cooling fan in the excitation system in this embodiment specifically includes the following steps: Step S1: After the fan starts, external cold air enters the cooling duct 5 through the air inlet filter to apply air force to the pressure plate 1, causing it to open. The system monitors the operating status of the limit switch 4; wherein, the pressure plate 1 opens after being subjected to the air force of the fan, triggering the limit switch 4.

[0034] The specific working principle is as follows: the limit switch 4 uses a normally open node for signal feedback; when the air pressure plate 1 is opened and triggers the limit switch 4, the normally open node closes to provide feedback that the fan is operating normally.

[0035] Combination Figure 3 The logic branch determines that if the limit switch 4 is activated, the fan is considered to be running normally. Conversely, if the limit switch 4 is not activated after the fan start signal is issued (i.e., ...), the fan is considered to be running normally. Figure 3 If the "No" branch of the intermediate-range switch action node is selected, the fan startup is directly determined to be abnormal. This step achieves "qualitative" monitoring of the fan start-up and shutdown status.

[0036] Step S2: After opening, the pressure plate 1 is blocked by the pressure plate baffle 2 to limit its opening. Under the continuous action of the fan's airflow, the pressure plate baffle 2 is compressed, causing the cylindrical ring strain gauge 3 to deform under the action of the pressure plate, thereby outputting real-time strain force data (i.e., entering...). Figure 3 (The "Strain Monitoring" process on the right).

[0037] The specific principle is as follows: the monitored object is the force exerted by the pressure plate on the baffle, which directly originates from the effective output air pressure of the fan. When the cylindrical ring strain gauge undergoes a slight deformation under pressure, its internal resistance changes. This change is converted into an electrical signal output through a built-in measuring bridge, thus accurately converting the mechanical force into real-time strain force data. This step achieves "quantitative" monitoring of the actual output of the fan, avoiding errors caused by indirect methods such as monitoring speed or current.

[0038] Step S3: Acquire the real-time strain force data and compare the real-time strain force data with a preset alarm threshold (corresponding to...). Figure 3 "Strain" (Rated wind pressure judgment node).

[0039] If the real-time strain data is greater than or equal to the alarm threshold, the fan pressure of the fan is determined to be normal. If the real-time strain data is less than the alarm threshold, the fan pressure of the fan is determined to be abnormal and an early warning is triggered.

[0040] To ensure the accuracy of early warnings and prevent false alarms, this embodiment features a specially designed preset alarm threshold: the preset alarm threshold is [value missing] of the rated wind pressure. .

[0041] More importantly, the formula for calculating the rated wind pressure is: ; in, The rated wind pressure, It is the minimum initial wind pressure value of the brand-new fans in the same batch in the monitored excitation system.

[0042] The step of obtaining the minimum value of the initial wind pressure includes: in a configuration with In the excitation system of the unit with multiple power cabinets, each power cabinet includes two wind turbines from the same batch, one main and one backup; obtain the... The initial wind pressure values ​​measured when the typhoon generator is in brand new condition are used as the minimum initial wind pressure value. .

[0043] Assume that the excitation system of a certain generating unit is configured with Power cabinets, totaling The typhoon fans are all from the same batch of equipment. When the fans are brand new, the measured initial air pressure values ​​are very similar. The system needs to calculate a uniform "rated air pressure" as a baseline value for alarm judgment of all fans. To avoid false alarms from perfectly good new fans immediately upon commissioning, it must be ensured that the initial air pressure value of all fans is higher than or equal to... The rated wind pressure. Based on this principle of preventing false alarms, the following must be met: The rated wind pressure must not exceed the minimum value among all initial wind pressure values, i.e. .

[0044] Therefore, the formula for setting the baseline is derived: After setting the rated wind pressure value in this way, the system's alarm conditions (i.e., real-time strain force data) will be... In mathematical logic, this is equivalent to "the real-time wind pressure being lower than the minimum initial wind pressure value of this batch of new air conditioners". This innovative algorithm ensures that new air conditioners will never trigger false alarms, and it can also detect the wind pressure of any air conditioner as soon as it begins to actually drop.

[0045] Further, see Figure 3 In the attribution branch at the end, when the processing controller determines that the wind force of the fan is abnormal, it is also configured to output the abnormality cause diagnosis result; the abnormality cause diagnosis result mainly includes the following three situations: ① The fan itself is abnormal: As the operating time accumulates, the fan bearings wear, the blades accumulate dust, or the motor ages, which leads to a decline in the fan's performance. In this case, the diagnosis suggests that checking and replacing the fan is the only solution. ② Insufficient air intake due to excessive dust accumulation in the air intake filter: Poor external ventilation causes physical obstruction of air intake, which in turn reduces the airflow established by the fan in the cooling duct. In this case, the diagnosis suggests that the filter needs to be checked and it is recommended to replace it. ③ The cylindrical ring strain gauge has an error: zero-point drift or error caused by long-term operation of the sensor itself, indicating that the strain gauge needs to be calibrated or replaced.

[0046] Example 2 Based on the same inventive concept as Embodiment 1, this embodiment provides a performance monitoring system for the heat dissipation fan of a forced air-cooled power cabinet in an excitation system. This system is the hardware implementation of the monitoring method described in Embodiment 1, and its actual operating logic and mathematical derivation process completely correspond to those of Embodiment 1.

[0047] Combination Figures 1 to 3 As shown, a fan is installed inside the power cabinet, and the monitoring system mainly includes a physical structure module (air guide) and a data logic module (processing controller). The specific structure and connection relationships are described below: I. Solid structural module (air guide) The air guide is installed entirely within the cooling air duct 5 of the power cabinet, and in order to obtain the dynamic air pressure output by the fan most directly, the air guide is installed directly above the fan.

[0048] The air guide mainly consists of a pressure plate 1, a pressure plate baffle 2, a cylindrical strain gauge 3 fixed to the pressure plate baffle 2, and a limit switch 4. The structural coordination relationship of each component is as follows: 1. Ductwork and pressure plate coordination: An air inlet filter is installed on the lower side of the power cabinet panel; after the fan starts, external cold air enters the cooling duct 5 through the air inlet filter to apply air force to the pressure plate 1, causing it to open. The pressure plate 1 is configured to open after being subjected to the air force of the fan, and trigger the limit switch 4 in conjunction.

[0049] 2. Limiting and force measuring mechanism: After the pressure plate 1 is opened, its maximum opening is limited by the pressure plate stop bar 2. Under the continuous action of the wind force from the fan, the pressure plate 1 will squeeze the pressure plate stop bar 2. Under this mechanical transmission, the cylindrical ring strain gauge 3 fixed on the stop bar will produce a small deformation. The mechanical deformation is converted into an electrical signal by the internal bridge circuit to output real-time strain force data.

[0050] 3. High-Reliability Cabling Structure: Considering the high wind speeds and strong electromagnetic interference environment inside the power cabinets of large and medium-sized hydropower stations, the cylindrical ring strain gauge 3 is equipped with a secondary signal transmission cable. This secondary signal transmission cable is cleverly integrated into the internal cavity of the wind pressure plate baffle 2 and leads out from the end of the wind pressure plate baffle 2 to the external processing controller. This structure avoids fatigue fracture caused by direct wind blowing on the cable and utilizes the metal baffle to achieve natural electromagnetic shielding.

[0051] II. Data Logic Module (Processing Controller) The processing controller (which may be a PLC, MCU, or other industrial control computer with data processing capabilities) is communicatively connected to the cylindrical ring strain gauge 3 and the limit switch 4, respectively. The processing controller is configured to execute the following monitoring and judgment logic: 1. Start-up and shutdown qualitative monitoring: After the fan starts, monitor the operation status of the limit switch 4 (whether the normally open contact is closed); if the operation of the limit switch 4 is detected, the fan is determined to be starting normally; if no operation is detected, the start-up is directly determined to be abnormal.

[0052] 2. Quantitative wind force monitoring: After determining that the operation is normal, the processing controller acquires the real-time strain force data output by the cylindrical ring strain gauge (3) in real time, and compares the real-time strain force data with the preset alarm threshold.

[0053] 3. Threshold Calculation and Anti-interference Logic: This logic processes or calculates the preset alarm threshold stored internally by the controller. The preset alarm threshold is [value missing] of the rated wind pressure. And its rated wind pressure is calculated using the following formula: .in, The rated wind pressure, For the monitored excitation system (total) The minimum initial wind pressure value among brand-new typhoon fans in the same batch. This extreme value algorithm ensures that the system can both accurately detect wind force attenuation and absolutely avoid false alarms when new fans are put into operation.

[0054] 4. Status Determination and Cause Diagnosis: If the real-time strain force data is greater than or equal to the alarm threshold, the processing controller determines that the fan's airflow is normal; if the real-time strain force data is less than the alarm threshold, the processing controller determines that the fan's airflow is abnormal and triggers an early warning. Simultaneously, when determining an abnormal airflow, the processing controller is also configured to output an abnormality cause diagnosis result; based on the on-site operating conditions, the abnormality cause diagnosis result is categorized as follows: fan body malfunction (fan replacement required), insufficient airflow due to dust accumulation on the inlet filter (filter replacement required), or detection error of the cylindrical ring strain gauge (calibration and replacement required).

[0055] Since the system provided in this embodiment 2 is a hardware system for implementing the monitoring method described in embodiment 1, its specific working mechanism, internal calculation derivation process, and beneficial technical effects (such as achieving preventive maintenance, more accurate direct measurement, and high reliability) are the same as those in embodiment 1. For the sake of brevity, they will not be repeated here.

[0056] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

[0057] This background section is provided to generally present the context of the invention. The work of the currently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither expressly nor impliedly acknowledged as prior art to the invention.

Claims

1. A method for monitoring the performance of a forced-air-cooled power cabinet cooling fan in an excitation system, characterized in that, Based on the monitoring system, a fan is installed inside the power cabinet. The monitoring system includes an air guide installed inside the power cabinet. The air guide includes a pressure plate (1), a pressure plate baffle (2), a cylindrical ring strain gauge (3) fixed on the pressure plate baffle (2), and a limit switch (4). The monitoring method includes the following steps: After the fan is started, the operation status of the limit switch (4) is monitored; wherein the wind pressure plate (1) is opened after being subjected to the wind force of the fan, and triggers the limit switch (4). If the limit switch (4) is detected to be activated, it is determined that the fan is operating normally; Wherein, the opening of the wind pressure plate (1) is restricted by the wind pressure plate baffle (2) after it is opened, and the wind pressure plate baffle (2) is squeezed under the continuous action of the wind force of the fan, so that the cylindrical ring strain gauge (3) deforms to output real-time strain force data; Acquire the real-time strain force data and compare the real-time strain force data with a preset alarm threshold; If the real-time strain data is greater than or equal to the alarm threshold, the wind force of the fan is determined to be normal. If the real-time strain data is less than the alarm threshold, the wind force of the wind turbine is determined to be abnormal and an early warning is triggered.

2. The method for monitoring the performance of a forced-air-cooled power cabinet cooling fan in an excitation system according to claim 1, characterized in that, The preset alarm threshold is the rated wind pressure. .

3. The method for monitoring the performance of a forced-air-cooled power cabinet cooling fan in an excitation system according to claim 2, characterized in that, The formula for calculating the rated wind pressure is: ； in, The rated wind pressure, It is the minimum initial wind pressure value of the brand-new fans in the same batch in the monitored excitation system.

4. The method for monitoring the performance of a forced-air-cooled power cabinet cooling fan in an excitation system according to claim 3, characterized in that, The steps for obtaining the minimum value of the initial wind pressure include: In configuration In the excitation system of the unit with a power cabinet, each power cabinet includes two fans from the same batch, one main and one backup. Obtain the The initial wind pressure values ​​measured when the typhoon generator is in brand new condition are used as the minimum initial wind pressure value. .

5. The method for monitoring the performance of a forced-air-cooled power cabinet cooling fan in an excitation system according to claim 1, characterized in that, The limit switch (4) is a normally open node; when the air pressure plate (1) is opened and triggers the limit switch (4) to act, the normally open node closes to provide feedback that the fan is running normally.

6. A performance monitoring system for a forced-air-cooled power cabinet cooling fan in an excitation system, characterized in that, Based on the monitoring method described in any one of claims 1 to 5, a fan is installed inside the power cabinet, and the monitoring system includes: An air guide is installed in the cooling air duct (5) of the power cabinet. The air guide includes a pressure plate (1), a pressure plate baffle (2), a cylindrical ring strain gauge (3) fixed on the pressure plate baffle (2), and a limit switch (4). The pressure plate (1) is configured to open after being subjected to the wind force of the fan and trigger the limit switch (4). After the pressure plate (1) is opened, its opening degree is limited by the pressure plate baffle (2), and under the continuous action of the wind force of the fan, the pressure plate baffle (2) is squeezed, causing the cylindrical ring strain gauge (3) to deform and output real-time strain force data. The processing controller is communicatively connected to the cylindrical ring strain gauge (3) and the limit switch (4) respectively. The processing controller is configured to: monitor the operation status of the limit switch (4) after the fan starts; if the operation of the limit switch (4) is detected, the fan is determined to be running normally, and the real-time strain force data is acquired; the real-time strain force data is compared with a preset alarm threshold; if the real-time strain force data is greater than or equal to the alarm threshold, the fan is determined to have normal wind force; if the real-time strain force data is less than the alarm threshold, the fan is determined to have abnormal wind force and an early warning is triggered.

7. A performance monitoring system for a forced-air-cooled power cabinet cooling fan in an excitation system according to claim 6, characterized in that, The cylindrical ring strain gauge (3) is equipped with a secondary signal transmission cable; the secondary signal transmission cable is built into the inside of the wind pressure plate baffle (2) and leads out from the end of the wind pressure plate baffle (2) to the processing controller.

8. A performance monitoring system for a forced-air-cooled power cabinet cooling fan in an excitation system according to claim 6, characterized in that, The air guide is installed directly above the fan.

9. A performance monitoring system for a forced-air-cooled power cabinet cooling fan in an excitation system according to claim 6, characterized in that, When the processing controller determines that the wind force of the fan is abnormal, it is also configured to output the abnormality cause diagnosis result; the abnormality cause diagnosis result includes: abnormality of the fan body, insufficient air intake due to dust accumulation on the air inlet filter, or detection error of the cylindrical ring strain gauge.

10. A performance monitoring system for a forced-air-cooled power cabinet cooling fan in an excitation system according to claim 9, characterized in that, The power cabinet has an air inlet filter located below the side of the cabinet. After the fan is started, external cold air passes through the air inlet filter and enters the cooling duct (5) to apply wind force to the air pressure plate (1) to open it.

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