A transformer cooling device temperature monitoring and energy-saving control method and system

Abstract

The application discloses a transformer cooling equipment temperature monitoring and energy-saving control method and system, relates to the technical field of transformer cooling control, and comprises the following steps: collecting transformer cooling operation data, forming top oil temperature rise and counting the number of cooler operation groups; extracting single-group cooler shutdown records, respectively processing according to the operation state and shutdown object of each group of coolers before shutdown, segmentally fitting the change of the top oil temperature rise after shutdown, forming the temperature transition time and temperature rise rate difference after cooler shutdown; matching the temperature transition time and temperature rise rate difference after cooler shutdown according to the current load current, screening the shutdown object and performing shutdown evaluation, and forming a shutdown control result; updating the number of cooler operation groups and effective shutdown records, cyclically executing the shutdown object screening and shutdown judgment, and forming a transformer cooling equipment energy-saving control result. The application realizes the representation of the temperature transition process after cooler shutdown and the dynamic feedback of group-by-group energy-saving shutdown under different operation combinations and load levels.

Description

Technical Field

[0001] This invention relates to the field of transformer cooling control technology, and in particular to a method and system for temperature monitoring and energy-saving control of transformer cooling equipment. Background Technology

[0002] Oil-immersed transformers generate continuous heat during operation, which is typically regulated by cooling equipment consisting of cooling fans, oil pumps, and radiators. Existing cooling control generally switches the operating status of the cooler according to predetermined control logic based on the top oil temperature, load current, ambient temperature, and temperature protection settings. It also monitors the operation of the cooling equipment in conjunction with cooling loop feedback to maintain the transformer's thermal stability while also considering the economic efficiency of the cooling equipment's operation.

[0003] However, existing methods still have two limitations: First, after the cooler is shut down, the oil flow and air flow have a gradual attenuation transition characteristic. Using a fixed waiting time or directly comparing the temperature before and after shutdown makes it difficult to distinguish between the temperature transition stage and the remaining cooler stabilization stage. Second, the shutdown impact varies under different cooler operating combinations and load levels. There is a lack of feedback evaluation that combines actual temperature trends and load trends, making it difficult to support energy-saving shutdown of each group. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention is proposed.

[0005] Therefore, this invention provides a method for temperature monitoring and energy-saving control of transformer cooling equipment, which solves the problems that the temperature transition process after the cooler is shut down is difficult to accurately characterize, and that there is a lack of dynamic feedback basis to support energy-saving shutdown of different operating combinations and load levels.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for temperature monitoring and energy-saving control of transformer cooling equipment, comprising: collecting transformer cooling operation data; generating a top oil temperature rise based on the top oil temperature and ambient temperature; and counting the number of operating cooler groups based on the operating status and operating current of each group of coolers; extracting single-group cooler shutdown records from the transformer cooling operation data; processing each group of coolers according to their operating status and shutdown targets before shutdown; performing segmented fitting on the top oil temperature rise change after shutdown to generate the temperature transition time and temperature rise rate difference after cooler shutdown; matching the temperature transition time and temperature rise rate difference after cooler shutdown based on the current operating status of each group of coolers and the current load current; filtering shutdown targets and determining whether to shut down based on the current top oil temperature change rate and the current load current change rate; and controlling the temperature rise after cooler shutdown. After the transition time ends, shutdown control results are generated based on the actual top oil temperature change rate and the actual load current change rate. A single-group cooler shutdown record is generated when the shutdown object is actually shut down and the shutdown evaluation is completed. The operating status and number of cooler operating groups of each group are updated based on the shutdown control results. The single-group cooler shutdown record is associated with the corresponding sampling period record in the transformer cooling operation data and stored accordingly. The valid shutdown records in each processing category are updated accordingly. When the shutdown object screening is re-executed, the temperature transition time and temperature rise rate difference after the cooler shutdown are matched according to the current load current. The shutdown object screening and shutdown judgment are cyclically executed until active energy-saving shutdown is no longer executed. The operating status and number of cooler operating groups of each group when active energy-saving shutdown is stopped are taken as the energy-saving control result of the transformer cooling equipment.

[0007] As a preferred embodiment of the transformer cooling equipment temperature monitoring and energy-saving control method of the present invention, the method of collecting transformer cooling operation data includes: during the operation of an oil-immersed transformer, collecting the top oil temperature, ambient temperature, and load current; reading the operating status of each group of coolers; collecting the operating current of each cooling fan motor in each group of coolers; and collecting the operating current of the corresponding oil pump motor when using forced oil circulation cooling; and storing the top oil temperature, ambient temperature, load current, operating status of each group of coolers, and operating current of each group of coolers at the same sampling time according to a unified sampling clock to form transformer cooling operation data.

[0008] As a preferred embodiment of the transformer cooling equipment temperature monitoring and energy-saving control method of the present invention, the step of generating a top oil temperature rise based on the top oil temperature and ambient temperature, and counting the number of cooler operating groups based on the operating status and operating current of each group of coolers, includes: taking the difference between the top oil temperature and the ambient temperature at the same sampling time as the top oil temperature rise; determining whether each group of coolers is actually operating based on the operating status of each group of coolers, the operating current of each cooling fan motor, and the operating current of the oil pump motor when using forced oil circulation cooling; when the operating status and operating current of each group of coolers are consistent, counting the number of coolers actually operating to obtain the number of cooler operating groups.

[0009] As a preferred embodiment of the transformer cooling equipment temperature monitoring and energy-saving control method of the present invention, the step of extracting single-group cooler shutdown records from transformer cooling operation data and processing them according to the operating status of each group of coolers before shutdown and the shutdown object includes: comparing the operating status and operating current of each group of coolers according to the sampling time; when only one group of coolers changes from the operating state to the shutdown state between two adjacent sampling times, the operating current of each cooling fan motor in the shutdown cooler changes from present to absent; when forced oil circulation cooling is used, the operating current of the oil pump motor changes from present to absent; and the operating status and operating current of the remaining groups of coolers are also considered. If the operation remains unchanged, determine the shutdown target and the actual shutdown time; continuously read the sampling period of each group of coolers maintaining the pre-shutdown operating state from the sampling time before the actual shutdown time to form the pre-shutdown continuous operating interval; continuously read the sampling period of each group of coolers maintaining the post-shutdown operating state from the actual shutdown time to form the post-shutdown continuous operating interval; associate and record the transformer cooling operation data of the pre-shutdown continuous operating interval, the actual shutdown time, the post-shutdown continuous operating interval, the shutdown target, and the corresponding sampling period to form a single group of cooler shutdown record; group the single group of cooler shutdown records with the same pre-shutdown operating state and the same shutdown target into the same processing category.

[0010] As a preferred embodiment of the transformer cooling equipment temperature monitoring and energy-saving control method of the present invention, the step of segmenting and fitting the top oil temperature rise change after shutdown to form the temperature transition time and temperature rise rate difference after the cooler shutdown includes: selecting six consecutive sampling times before the actual shutdown time from the continuous operating interval before shutdown to form a load current reference interval before shutdown, and forming a load current fluctuation range before shutdown based on the minimum and maximum values ​​of the load current within the load current reference interval before shutdown; when the load current at the actual shutdown time is within the load current fluctuation range before shutdown, reading the load current in the continuous operating interval after shutdown from the actual shutdown time, and determining the load current fluctuation range based on the first time the load current exceeds... The sampling time of the load current fluctuation range before shutdown determines the observation interval after shutdown. Candidate segment boundaries are set within the observation interval after shutdown. Least square linear fitting is performed on the top oil temperature rise before and after each candidate segment boundary. The piecewise fitting error is formed based on the sum of squared residuals of the two fitting segments. The sampling time of the first top oil temperature rise sample value after the candidate segment boundary with the smallest piecewise fitting error is taken as the end time of temperature transition. The duration between the actual shutdown time and the end time of temperature transition is taken as the temperature transition time after the cooler shutdown. The temperature transition time after the cooler shutdown limits the calculation period of the temperature rise rate before and after shutdown, and the temperature rise rate difference is formed based on the change of top oil temperature rise before and after shutdown.

[0011] As a preferred embodiment of the transformer cooling equipment temperature monitoring and energy-saving control method of the present invention, the step of forming a temperature rise rate difference based on the change in top oil temperature before and after shutdown includes: taking the sampling time before the actual shutdown time as the end point of the interval, selecting a continuous sampling period with the same duration as the temperature transition time after the cooler shutdown from the continuous operating interval before shutdown, forming a temperature rise rate calculation interval before shutdown; taking the end time of the temperature transition as the start point of the interval, selecting a continuous sampling period with the same duration as the temperature transition time after the cooler shutdown from the observation interval after shutdown, forming a temperature rise rate calculation interval after shutdown; performing least squares linear fitting on the top oil temperature rise in the temperature rise calculation interval before and after shutdown respectively, and taking the difference between the temperature rise rate of the top oil after shutdown and the temperature rise rate of the top oil before shutdown as the temperature rise rate difference; associating and storing the temperature transition time after the cooler shutdown, the temperature rise rate difference, and the load current fluctuation range before shutdown with the operating status and shutdown object of each group of coolers before shutdown, forming an effective shutdown record of the corresponding processing category.

[0012] As a preferred embodiment of the transformer cooling equipment temperature monitoring and energy-saving control method of the present invention, the step of screening shutdown targets and determining whether to shut down includes: according to the current operating status of each group of coolers and the coolers currently in operation, screening load matching shutdown records from the valid shutdown records of the corresponding processing category, where the current load current is within the fluctuation range of the load current before shutdown; arranging the temperature transition time and temperature rise rate difference after shutdown in the load matching shutdown records according to their values ​​and determining the median value; selecting coolers currently in operation with a median temperature rise rate difference greater than zero as candidate shutdown targets; selecting the candidate shutdown target with the smallest temperature rise rate difference as the shutdown target; when multiple candidate shutdown targets have the same temperature rise rate difference, selecting the candidate shutdown target with the shortest temperature transition time after shutdown as the shutdown target; when both the temperature rise rate difference and the temperature transition time after shutdown are the same, under the condition that the power supply voltage and power supply phase system of each candidate shutdown target are the same, respectively... The current operating current of each cooling fan motor in the candidate shutdown targets is summed. When forced oil circulation cooling is used, the current operating current of the oil pump motor is also summed to obtain the total current operating current value. The candidate shutdown target with the largest total current operating current value is selected as the shutdown target. The current rate of change is calculated within a time interval with the current sampling time as the interval endpoint and the same duration as the temperature transition time after the cooler is shut down. Least square linear fitting is performed on the top oil temperature rise, ambient temperature, and load current to form the current top oil temperature rise rate, the current ambient temperature rate, and the current load current rate. The sum of the current top oil temperature rise rate and the current ambient temperature rate is taken as the current top oil temperature rate. The sum of the difference between the current top oil temperature rate and the temperature rise rate corresponding to the shutdown target is taken as the expected top oil temperature rate after shutdown. When both the current load current rate and the expected top oil temperature rate after shutdown are not greater than zero, a shutdown control command is issued to the shutdown target; otherwise, shutdown is not executed.

[0013] As a preferred embodiment of the transformer cooling equipment temperature monitoring and energy-saving control method of the present invention, the step of forming a shutdown control result based on the actual top oil temperature change rate and the actual load current change rate, and forming a single set of cooler shutdown records when the shutdown object is actually shut down and the shutdown evaluation is completed, includes: after issuing the shutdown control command, continuously reading the operating status and operating current of the shutdown object, taking the sampling moment when the shutdown object is first in a shutdown state and all operating currents are absent as the actual shutdown moment, and taking the first sampling moment when the cumulative duration from the actual shutdown moment reaches the temperature transition time after the cooler shutdown as the temperature transition end moment; selecting a shutdown evaluation interval with the same duration as the temperature transition time after the cooler shutdown, using the temperature transition end moment as the interval starting point, and performing least squares linear fitting on the top oil temperature and load current in the shutdown evaluation interval to form the actual top oil temperature change rate and the actual load current change rate; when the actual top oil temperature change rate and the actual load current change rate are... When the actual load current change rate is not greater than zero, the shutdown control result is recorded as "maintain shutdown". When the actual top oil temperature change rate or the actual load current change rate is greater than zero, a resumption command is issued to the shutdown object, and the shutdown control result is recorded as "resumption of operation". After the shutdown object is actually shut down and the shutdown evaluation is completed, the continuous sampling period of each group of coolers maintaining the pre-shutdown operating state before the actual shutdown time is taken as the pre-shutdown continuous operating interval, and the continuous sampling period between the actual shutdown time and the end of the shutdown evaluation interval is taken as the post-shutdown recording interval. The transformer cooling operation data in the shutdown object, the actual shutdown time, the operating state of each group of coolers before shutdown, and the pre-shutdown continuous operating interval and the post-shutdown recording interval are linked and recorded to form a single group of cooler shutdown record. During the temperature transition and shutdown evaluation period after the cooler shutdown, when the original temperature protection or cooling control of the oil-immersed transformer issues a cooler commissioning command, the shutdown evaluation is terminated and the cooler commissioning command is executed.

[0014] As a preferred embodiment of the transformer cooling equipment temperature monitoring and energy-saving control method of the present invention, the following steps are included: cyclically executing shutdown object screening and shutdown judgment until active energy-saving shutdown is no longer performed; using the operating status and number of operating cooler groups at the time of cessation of active energy-saving shutdown as the energy-saving control result of the transformer cooling equipment; this includes: after each shutdown control result is formed, reading the operating status and operating current of each group of coolers; when the operating status and operating current of each group of coolers are consistent, updating the operating status and number of operating cooler groups; assigning newly formed single-group cooler shutdown records to matching processing categories; and updating the effective shutdown of the corresponding processing category after the temperature transition time and temperature rise rate difference after the cooler shutdown is formed. Record: When the shutdown control result is to maintain shutdown, the updated operating status of each group of coolers is used as the current operating status of each group of coolers. Based on the current load current, the temperature transition time and temperature rise rate difference after the cooler shutdown are rematched from the updated valid shutdown records, and the shutdown object screening and shutdown judgment are re-executed. Each active energy-saving shutdown only controls one group of coolers to stop operating. When the shutdown control result is not to maintain shutdown, the operating status of any group of coolers is inconsistent with the operating current, or the original temperature protection or cooling control of the oil-immersed transformer issues a cooler commissioning command, the active energy-saving shutdown is stopped, and the operating status of each group of coolers and the number of cooler operating groups at the time of stopping the active energy-saving shutdown are used as the energy-saving control result of the transformer cooling equipment.

[0015] Secondly, this invention provides a temperature monitoring and energy-saving control system for transformer cooling equipment, comprising: a cooling monitoring module for collecting transformer cooling operation data, generating top oil temperature rise based on top oil temperature and ambient temperature, and counting the number of operating cooler groups based on the operating status and operating current of each group of coolers; a shutdown analysis module for extracting shutdown records of individual coolers from the transformer cooling operation data, classifying processing categories according to the operating status and shutdown object of each group of coolers before shutdown, performing segmented fitting on the top oil temperature rise change after shutdown, and generating temperature transition time, temperature rise rate difference, and effective shutdown records after cooler shutdown; and an energy-saving control module. The first module is used to screen shutdown targets and determine whether to shut them down based on the current operating status of each group of coolers and the difference in temperature transition time and temperature rise rate after the current load current matches the current operating status of each group of coolers. It generates shutdown control results based on the actual top oil temperature change rate and the actual load current change rate after shutdown, and generates a shutdown record for a single group of coolers when the shutdown evaluation is completed. The second module is used to update the operating status of each group of coolers, the number of cooler operating groups, and the valid shutdown records in each processing category based on the shutdown control results. It cyclically executes shutdown target screening and shutdown judgment until active energy-saving shutdown is no longer executed, and generates energy-saving control results for transformer cooling equipment.

[0016] The beneficial effects of this invention are as follows: by segmenting and fitting the top oil temperature rise after shutdown and comparing the temperature rise rate over the same duration before and after shutdown, the segmented positions of the top oil temperature rise change after the cooler shutdown are determined, and the temperature rise changes corresponding to different cooler operating combinations and shutdown objects are characterized; by matching the current operating status of each group of coolers and the current load current with the shutdown characteristics, combined with the judgment of the expected top oil temperature change after shutdown, shutdown evaluation, and updating of effective shutdown records, the shutdown objects are screened group by group and the shutdown conditions are dynamically confirmed, forming an energy-saving control result for transformer cooling equipment that is adapted to the actual cooling capacity. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a method for temperature monitoring and energy-saving control of transformer cooling equipment.

[0019] Figure 2 This is a schematic diagram of a temperature monitoring and energy-saving control system for transformer cooling equipment.

[0020] Figure 3 This is a flowchart showing the temperature transition time and temperature rise rate difference after the cooler is shut down.

[0021] Figure 4 A flowchart for the cyclical updating of shutdown object screening and shutdown evaluation.

[0022] Figure 5 This is a segmented fitting diagram of the top oil temperature rise after the cooler is shut down.

[0023] Figure 6 This is a graph showing the change in the number of cooler operating groups under shutdown control results. Detailed Implementation

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0026] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0027] Reference Figures 1-6 As one embodiment of the present invention, this embodiment provides a method for temperature monitoring and energy-saving control of transformer cooling equipment, including the following steps: S1. Collect transformer cooling operation data, calculate the top oil temperature rise based on the top oil temperature and ambient temperature, and count the number of cooler operating groups based on the operating status and operating current of each group of coolers.

[0028] Furthermore, the monitoring object of the present invention is an oil-immersed transformer equipped with multiple sets of coolers. Each set of coolers operates at a constant speed and is equipped with one or more cooling fans. When a forced oil circulation cooling method is adopted, each set of coolers is also equipped with an oil pump. The cooling fans and oil pumps are put into operation or stopped according to the original cooling control relationship of the oil-immersed transformer, and the cooling capacity of the oil-immersed transformer is changed by putting into operation or stopping the entire set of coolers.

[0029] During the operation of an oil-immersed transformer, the top oil temperature is collected by a top oil temperature detection device, the ambient temperature is collected by an ambient temperature detection device located around the transformer, the load current is collected by a load current monitoring circuit, the operating status of each group of coolers is read by a cooling control circuit, and the operating current of each group of coolers is collected by a current detection device in the cooler motor circuit. The operating current of each group of coolers includes the operating current of each cooling fan motor in each group of coolers, as well as the operating current of the oil pump motor when forced oil circulation cooling is used. The top oil temperature, ambient temperature, load current, operating status of each group of coolers, and operating current of each group of coolers are recorded synchronously according to a unified sampling clock. The top oil temperature, ambient temperature, load current, operating status of each group of coolers, and operating current of each group of coolers at the same sampling time are associated and stored to form transformer cooling operation data. Among them, the same sampling interval is used for extracting single group of cooler shutdown records, forming valid shutdown records, performing shutdown object screening, and shutdown evaluation of transformer cooling operation data.

[0030] It should be noted that the operating status of each group of coolers represents the operating or shutdown status fed back by the cooling control loop, and the operating current of each group of coolers represents the actual operating current of each cooling fan motor when the cooler is in operation, and the actual operating current of the oil pump motor when forced oil circulation cooling is used. For each cooling fan motor and oil pump motor, the upper limit of the zero current measurement error is read from the equipment parameters of the corresponding current detection device as the operating current judgment value of the corresponding motor, and the operating current judgment value is lower than the lower limit of the normal operating current range of the corresponding motor. When the operating current detection value is greater than the operating current judgment value, it is determined that the corresponding motor has operating current; otherwise, it is determined that the corresponding motor does not have operating current.

[0031] Furthermore, the top oil temperature and ambient temperature at the same sampling time are read from the transformer cooling operation data. The difference between the top oil temperature and the ambient temperature is taken as the top oil temperature rise at the current sampling time. The top oil temperature rise is continuously recorded according to the sampling time, and the top oil temperature rise is associated with the record of the same sampling time in the transformer cooling operation data and stored.

[0032] It should be noted that the top oil temperature rise indicates the degree of increase in top oil temperature relative to the ambient temperature. Compared with using the top oil temperature alone, the top oil temperature rise can reduce the impact of different ambient temperatures on the temperature changes of the transformer, making the temperature changes of the cooler before and after operation or shutdown in different operating periods comparable.

[0033] Furthermore, the operating status and operating current of each group of coolers at the same sampling time are read from the transformer cooling operation data, and each group of coolers is judged to be actually operating. When a group of coolers is in the operating state, and the cooling fans and oil pumps that should be running according to the original cooling control relationship of the oil-immersed transformer have operating current, the current cooler is counted as an operating cooler. When a group of coolers is in the operating state, and the cooling fans and oil pumps set according to the original cooling control relationship of the oil-immersed transformer have no operating current, the current cooler is not counted as an operating cooler. When a group of coolers is in the operating state, but according to the original cooling control relationship of the oil-immersed transformer, the cooling fans and oil pumps have no operating current, the current cooler is not counted as an operating cooler. If the cooling fans or oil pumps that the original cooling control relationship of the transformer need to operate do not have operating current, or if the operating status of a group of coolers is in a stopped state, but the cooling fans or oil pumps installed in the current cooler still have operating current, the operating status and operating current are recorded inconsistently. The number of cooler operating groups at the current sampling time is not counted, nor is the single group of cooler shutdown record extracted from the current sampling time. When the operating status and operating current of each group of coolers are consistent at the same sampling time, the number of operating coolers is counted to obtain the number of cooler operating groups at the current sampling time, and the number of cooler operating groups is associated with the record of the same sampling time in the transformer cooling operation data and stored.

[0034] It should be noted that the number of cooler operating groups represents the number of coolers actually performing cooling work at the same sampling time; the actual operation of a cooler is determined by the operating status and operating current of each group of coolers, so as to avoid including coolers whose operating status is inconsistent with the actual operating situation in the number of cooler operating groups.

[0035] S2. Extract the shutdown records of a single group of coolers from the transformer cooling operation data, process them separately according to the operating status of each group of coolers before shutdown and the shutdown object, and perform segmented fitting on the temperature rise change of the top oil after shutdown to form the temperature transition time and temperature rise rate difference after the cooler shutdown.

[0036] Furthermore, the operating status and operating current of each group of coolers in the transformer cooling operation data are compared sequentially according to the sampling time.

[0037] When only one cooler changes from an operational state to a shutdown state between two adjacent sampling times, and the operating current of each cooling fan motor in the shutdown cooler changes from present to absent, and the operating current of the oil pump motor also changes from present to absent when the oil pump is installed, while the operating states of the other coolers remain unchanged and the presence or absence of operating current does not change, the cooler that has experienced the shutdown change is taken as the shutdown object, and the sampling time when the shutdown object is simultaneously in a shutdown state and all operating currents are absent is taken as the actual shutdown time.

[0038] Transformer cooling operation data is read backward from the sampling time preceding the actual shutdown time. This is done continuously while each group of coolers maintains its pre-shutdown operating state and its operating state matches the operating current, until the operating state of any cooler changes, becomes inconsistent with the operating current, or the data is read up to the starting sampling time of the transformer cooling operation data. This continuously read sampling period is taken as the continuous operating interval before shutdown. Then, transformer cooling operation data is read backward from the actual shutdown time. This is done continuously while each group of coolers maintains its post-shutdown operating state and its operating state matches the operating current, until the operating state of any cooler changes again, becomes inconsistent with the operating current, or the data is read up to the last sampling time of the transformer cooling operation data. This continuously read sampling period is taken as the continuous operating interval after shutdown.

[0039] The operating status of each cooler group at the sampling time before the actual shutdown time is taken as the operating status of each cooler group before shutdown. The continuous operating range before shutdown, the actual shutdown time, the continuous operating range after shutdown, the shutdown object, and the top oil temperature rise, load current, operating status of each cooler group, and operating current of each cooler group at the corresponding sampling time are recorded together to form a single cooler shutdown record.

[0040] It should be noted that when there are two or more coolers changing from the operating state to the off state between two adjacent sampling times, or when a cooler changes from the off state to the operating state, or when the operating state of any cooler is inconsistent with the operating current, a single cooler shutdown record will not be generated.

[0041] Furthermore, the shutdown records of each group of coolers are processed separately according to their operating status before shutdown and the object to be shut down.

[0042] Before shutdown, the shutdown records of single groups of coolers with the same operating status and the same shutdown target are classified into the same processing category; the shutdown records of single groups of coolers with different operating status or different shutdown targets before shutdown are classified into different processing categories.

[0043] It should be noted that processing each cooler group according to its operating status before shutdown can distinguish the temperature changes caused by the shutdown object under different cooler operating combinations; processing each shutdown object separately can distinguish the temperature changes caused by different coolers after shutdown, avoiding the combined processing of top oil temperature rise changes corresponding to different cooler operating combinations or different shutdown objects.

[0044] Furthermore, taking the sampling time before the actual shutdown time as the end point of the interval, six consecutive sampling times are selected from the continuous operating interval before shutdown along the decreasing direction of the sampling time as the reference interval for the load current before shutdown; when there are fewer than six consecutive sampling times in the continuous operating interval before shutdown, segmented fitting is not performed on the shutdown record of a single cooler; when the reference interval for the load current before shutdown is formed, the load current is read from the reference interval for the load current before shutdown, and the range between the minimum and maximum values ​​of the load current in the reference interval for the load current before shutdown is taken as the fluctuation range of the load current before shutdown.

[0045] Starting from the actual shutdown time, the load current within the continuous operating interval after shutdown is read sequentially according to the sampling time. When the load current at the actual shutdown time has exceeded the load current fluctuation range before shutdown, no segmented fitting is performed on the shutdown record of a single cooler. When the load current after the actual shutdown time exceeds the load current fluctuation range before shutdown for the first time, the sampling time before the sampling time that first exceeds the load current fluctuation range before shutdown is taken as the end point of the observation interval after shutdown. When the load current within the continuous operating interval after shutdown does not exceed the load current fluctuation range before shutdown, the last sampling time of the continuous operating interval after shutdown is taken as the end point of the observation interval after shutdown. The continuous sampling period between the actual shutdown time and the end point of the observation interval after shutdown is taken as the observation interval after shutdown.

[0046] If there are fewer than six top oil temperature rise sampling values ​​in the observation interval after shutdown, no segmented fitting will be performed on the shutdown record of a single cooler; if there are no fewer than six top oil temperature rise sampling values ​​in the observation interval after shutdown, no fewer than three top oil temperature rise sampling values ​​will be retained on the front and back sides of the candidate segment boundary.

[0047] It should be noted that each fitting segment retains no fewer than three top oil temperature rise sampling values. This can prevent two-point fitting from fixing the sum of squared residuals of the corresponding segment to zero, and allows the segment fitting errors of different candidate segment boundaries to be compared. Therefore, at least six top oil temperature rise sampling values ​​are required in the observation interval after shutdown.

[0048] Furthermore, the top oil temperature rise sampling values ​​within the observation interval after shutdown are arranged according to the sampling time. Candidate segment boundaries are set sequentially between two adjacent top oil temperature rise sampling values, ensuring that each candidate segment boundary contains at least three top oil temperature rise sampling values ​​on both the front and back sides. The sampling time of the first top oil temperature rise sampling value on the back side of each candidate segment boundary is taken as the candidate temperature transition end time.

[0049] For any candidate segment boundary, the actual shutdown time is used as the timing start point, and the duration between the sampling time of each top oil temperature rise sample value and the actual shutdown time is used as the sampling duration. Least squares linear fitting is performed on the top oil temperature rise sample values ​​between the actual shutdown time and the last top oil temperature rise sample value before the candidate segment boundary to obtain the slope and intercept of the fitted line for the transition section. Least squares linear fitting is also performed on the top oil temperature rise sample values ​​between the first top oil temperature rise sample value after the candidate segment boundary and the end point of the observation interval after shutdown to obtain the slope and intercept of the fitted line for the transition end section.

[0050] Calculate the squared residuals between the sampled top oil temperature rise values ​​in each transition section and the fitted line of the transition section, and sum the squared residuals within the transition section. Calculate the squared residuals between the sampled top oil temperature rise values ​​in each transition end section and the fitted line of the transition end section, and sum the squared residuals within the transition end section. Add the sums of the squared residuals for the two sections to obtain the piecewise fitting error of the current candidate segment boundary, expressed as: ; in, The sampling order of the last top layer oil temperature rise sample value before the candidate segment boundary is: The corresponding piecewise fitting error at that time; This indicates the sampling order of the last top-layer oil temperature rise sample value before the candidate segment boundary within the observation interval after shutdown, with a value range of [value range missing]. ; This indicates the sampling order of the top oil temperature rise sampling values ​​within the observation interval after shutdown; This indicates the number of top-layer oil temperature rise sampling values ​​within the observation interval after shutdown; Indicates the first The time between the sampling time of each top oil temperature rise sample and the actual shutdown time is the same as the unit of the temperature transition time after the cooler is shut down; Indicates the first One top-layer oil temperature rise sampling value; and These represent the slopes of the fitted straight lines in the transition section and the fitted straight lines in the transition end section, respectively, with the same units as the rate of change of the top layer oil temperature. and These represent the intercepts of the fitted straight line in the transition section and the fitted straight line in the transition end section, respectively, with the same units as the top oil temperature rise; the unit of the piecewise fitting error is the square of the top oil temperature rise unit.

[0051] Compare the segment fitting errors of all candidate segment boundaries, and take the candidate temperature transition end time corresponding to the candidate segment boundary with the smallest segment fitting error as the temperature transition end time; when there are multiple candidate segment boundaries with the same segment fitting error, take the earliest candidate temperature transition end time as the temperature transition end time; take the time between the actual shutdown time and the temperature transition end time as the temperature transition time after the current single group of coolers shutdown record.

[0052] It should be noted that after the cooler stops operating, the oil flow and air flow inside the cooler need to gradually decrease over a period of time. Different sampling sections after the actual shutdown time may show different trends in the top oil temperature rise. By comparing the segment fitting errors of different candidate segment boundaries, the segment position of the top oil temperature rise change is determined, and the corresponding candidate temperature transition end time is used as the temperature transition end time to form the temperature transition time after the cooler stops operating. The candidate segment boundary is determined based on the sum of the squares of the residuals of the two fitting sections before and after it, and is not based on the intersection or continuity of the fitting line of the transition section and the fitting line of the transition end section. This avoids uniformly using the same waiting time to divide the temperature transition process after the cooler stops operating for different cooler operating combinations and load levels.

[0053] Furthermore, taking the sampling time preceding the actual shutdown time as the end of the interval, a continuous sampling period of the same length as the temperature transition time after the cooler shuts down is selected along the decreasing direction of the sampling time as the interval for calculating the temperature rise rate before shutdown; taking the end of the temperature transition time as the start of the interval, a continuous sampling period of the same length as the temperature transition time after the cooler shuts down is selected along the increasing direction of the sampling time as the interval for calculating the temperature rise rate after shutdown.

[0054] When the temperature rise rate calculation interval before shutdown is within the continuous operation interval before shutdown, and the temperature rise rate calculation interval after shutdown is within the observation interval after shutdown, and both temperature rise rate calculation intervals contain at least two top oil temperature rise sampling values, a temperature rise rate difference is formed for the shutdown record of a single cooler group; when any temperature rise rate calculation interval exceeds the corresponding interval range, or when any temperature rise rate calculation interval contains fewer than two top oil temperature rise sampling values, the shutdown record of a single cooler group is retained, and a temperature rise rate difference is not formed for the shutdown record of a single cooler group.

[0055] Least squares linear fitting was performed on the top-layer oil temperature rise within the calculation intervals for the temperature rise rate before and after shutdown. The slope of the fitted line before shutdown was taken as the rate of change of the top-layer oil temperature rise before shutdown, and the slope of the fitted line after shutdown was taken as the rate of change of the top-layer oil temperature rise after shutdown. The rate of change of the top-layer oil temperature rise represents the degree of change of the top-layer oil temperature rise with the sampling time. The unit of the rate of change of the top-layer oil temperature rise is the ratio of the top-layer oil temperature rise unit to the sampling time unit. The same unit was used for the rate of change of the top-layer oil temperature rise before and after shutdown.

[0056] The difference between the rate of change of the top layer oil temperature after shutdown and the rate of change of the top layer oil temperature before shutdown is taken as the temperature rise rate difference of a single cooler shutdown record. A temperature rise rate difference greater than zero indicates that the upward trend of the top layer oil temperature rise after the single cooler shutdown is strengthened or the downward trend is weakened. A temperature rise rate difference equal to zero indicates that the temperature rise trend of the top layer oil remains unchanged before and after shutdown. A temperature rise rate difference less than zero indicates that the upward trend of the top layer oil temperature rise after the single cooler shutdown is weakened or the downward trend is strengthened.

[0057] It should be noted that the calculation intervals for the temperature rise rate before and after shutdown are both limited by the temperature transition time after the cooler is shut down, so that the temperature rise rate of the top oil before and after shutdown can be compared under the same time conditions, and avoids setting a fixed calculation time for the temperature rise rate separately.

[0058] Furthermore, for single-group cooler shutdown records that have completed piecewise fitting and formed a temperature rise rate difference within the same processing category, the temperature transition time after shutdown, temperature rise rate difference, and load current fluctuation range before shutdown of each single-group cooler shutdown record are associated and stored with the operating status and shutdown object of each group of coolers before shutdown, forming a valid shutdown record for the corresponding processing category; when there are no single-group cooler shutdown records that have completed piecewise fitting and formed a temperature rise rate difference within the same processing category, a valid shutdown record for the corresponding processing category is not formed.

[0059] S3. Based on the current operating status of each group of coolers and the difference in temperature transition time and temperature rise rate after the cooler is shut down, and combined with the current top oil temperature change rate and the current load current change rate, screen the shutdown targets and determine whether to shut down. After the temperature transition time after the cooler is shut down, form the shutdown control result based on the actual top oil temperature change rate and the actual load current change rate, and form a single group of cooler shutdown record when the shutdown target is actually shut down and the shutdown evaluation is completed.

[0060] Furthermore, the operating status and operating current of each group of coolers at the current sampling time are read from the transformer cooling operation data, and the load current at the current sampling time is also read. When the operating status and operating current of each group of coolers are consistent, the coolers currently in operation are read one by one. According to the current operating status of each group of coolers and the coolers currently in operation, the processing category of each group of coolers with the same operating status and the same shutdown object before shutdown is found, and the valid shutdown records in the corresponding processing category are read.

[0061] For any cooler currently in operation, select valid shutdown records from the valid shutdown records of the corresponding processing category. These records will be selected as load matching shutdown records, provided that the current load current is not less than the lower limit of the load current fluctuation range before shutdown and not greater than the upper limit of the load current fluctuation range before shutdown.

[0062] Arrange the temperature transition time and temperature rise rate difference after cooler shutdown in the load matching shutdown records in ascending order of value; when the number of load matching shutdown records is odd, take the value in the middle position of the arrangement as the median value; when the number of load matching shutdown records is even, take the average of the two middle values ​​of the arrangement as the median value.

[0063] When the median value of the temperature rise rate difference in the load matching shutdown record is greater than zero, the median value of the temperature transition time after the cooler is shut down and the median value of the temperature rise rate difference are respectively used as the temperature transition time and temperature rise rate difference after the cooler is shut down matched by the cooler currently in operation, and the cooler that has completed the matching is regarded as a candidate shutdown object; when there is no load matching shutdown record, or the median value of the temperature rise rate difference in the load matching shutdown record is not greater than zero, the cooler currently in operation is not regarded as a candidate shutdown object.

[0064] When the operating status and operating current of each group of coolers are inconsistent, or when the coolers currently in operation have not matched the temperature transition time and temperature rise rate difference after the cooler is shut down, no shutdown object screening will be performed, and the shutdown control result will be recorded as no shutdown will be executed.

[0065] It should be noted that the operating status of each group of coolers, the coolers currently in operation, and the current load current are matched simultaneously to ensure that the temperature transition time and temperature rise rate difference after the cooler is shut down are consistent with the current cooler operating combination, the object being shut down, and the load current level.

[0066] Furthermore, the temperature rise rate difference corresponding to each candidate shutdown object is compared, and the candidate shutdown object with the smallest temperature rise rate difference is selected as the shutdown object; when the temperature rise rate difference corresponding to multiple candidate shutdown objects is the same, the candidate shutdown object with the shortest temperature transition time after the cooler stops is selected as the shutdown object; when the temperature rise rate difference corresponding to multiple candidate shutdown objects and the temperature transition time after the cooler stops are the same, under the condition that the cooling fan motor and oil pump motor in each candidate shutdown object use the same power supply voltage and the same power supply phase system, the current operating current of each cooling fan motor in each candidate shutdown object is summed, and when setting the oil pump, the current operating current of the oil pump motor is summed as well, to obtain the total current operating current value of each candidate shutdown object, and the candidate shutdown object with the largest current operating current value is selected as the shutdown object.

[0067] It should be noted that the smaller the temperature rise rate difference, the smaller the impact of the candidate shutdown object on the temperature rise trend of the top oil after it stops operating; when the temperature rise rate difference is the same, the shorter the temperature transition time after the cooler stops operating, the shorter the time required to complete the shutdown evaluation; under the condition that the power supply voltage and power supply phase system of each candidate shutdown object are the same, the current total operating current value is only used for comparing the operating current scale between parallel candidate shutdown objects, and does not represent the actual power consumption.

[0068] Furthermore, taking the current sampling time as the end point of the interval, a continuous sampling period with the same duration as the temperature transition time after the shutdown of the corresponding cooler is selected along the decreasing direction of the sampling time, as the current rate of change calculation interval; within the current rate of change calculation interval, the operating state of each group of coolers remains unchanged, the operating state of each group of coolers is consistent with the operating current, and there are no less than three sampling values ​​of top oil temperature rise, ambient temperature, and load current, respectively, least squares linear fitting is performed on the top oil temperature rise, ambient temperature, and load current, the slope of the fitted line of top oil temperature rise is taken as the current rate of change of top oil temperature, the slope of the fitted line of ambient temperature is taken as the current rate of change of ambient temperature, the slope of the fitted line of load current is taken as the current rate of change of load current, and the sum of the current rate of change of top oil temperature rise and the current rate of change of ambient temperature is taken as the current rate of change of top oil temperature.

[0069] If the duration of continuous operation of each cooler group is shorter than the temperature transition time after the cooler is shut down, if the operating status and operating current of any cooler group are inconsistent within the current rate of change calculation interval, or if there are fewer than three sampling values ​​of top oil temperature rise, ambient temperature, or load current, the shutdown object will not be shut down, and the shutdown control result will be recorded as not performing shutdown.

[0070] Furthermore, the sum of the difference between the current rate of change of top oil temperature and the rate of change of temperature corresponding to the shutdown target is used as the expected rate of change of top oil temperature after shutdown, and the sum of the expected rate of change of top oil temperature after shutdown and the current rate of change of ambient temperature is used as the expected rate of change of top oil temperature after shutdown. When the current rate of change of load current is not greater than zero and the expected rate of change of top oil temperature after shutdown is not greater than zero, a shutdown control command is issued to the shutdown target. When the current rate of change of load current is greater than zero, or the expected rate of change of top oil temperature after shutdown is greater than zero, no shutdown control command is issued to the shutdown target, and the shutdown control result is recorded as shutdown not being executed.

[0071] It should be noted that the temperature transition time after the cooler is shut down is used to limit the duration of the current rate of change calculation interval; the temperature rise rate difference reflects the difference in the rate of change of the top oil temperature before and after the shutdown of the shut-down object. The operation or shutdown of the cooler does not directly change the ambient temperature. Therefore, the temperature rise rate difference is combined with the current rate of change of the top oil temperature to obtain the expected rate of change of the top oil temperature after shutdown. Then, combined with the current rate of change of the ambient temperature, the expected rate of change of the top oil temperature after shutdown is obtained. The changes in the current top oil temperature rise, ambient temperature, and load current under the current operating conditions are characterized by the current rate of change of the top oil temperature, the current rate of change of the ambient temperature, and the current rate of change of the load current, respectively. If the expected rate of change of the top oil temperature after shutdown is not greater than zero, it means that the top oil temperature is expected to remain unchanged or continue to decrease after the shutdown object stops operating. If the current rate of change of the load current is not greater than zero, it means that the current load is not showing an upward trend. Shutdown is executed when both rates of change meet the shutdown conditions to avoid reducing the number of cooler operating groups when the top oil temperature is expected to rise or the load current continues to increase.

[0072] Furthermore, after the shutdown control command is issued, the operating status and operating current of the shutdown object are continuously read. When the shutdown object reports a shutdown state, and the operating current of each cooling fan motor in the shutdown object is absent, and the operating current of the oil pump motor is also absent when the oil pump is set, the sampling moment when the shutdown object first simultaneously meets the conditions of operating status being shutdown and all operating currents being absent is taken as the actual shutdown moment.

[0073] After the cooling control loop feedback shutdown control command is executed, if the shutdown object still reports as in operation and the operating current of each cooling fan motor in the shutdown object still exists, and the operating current of the oil pump motor still exists when the oil pump is set, the shutdown evaluation will not be entered, and the shutdown control result will be recorded as shutdown execution failure; when the operating status of the shutdown object is inconsistent with the operating current, a resumption command will be issued to the shutdown object, and the shutdown control result will be recorded as resumption of operation.

[0074] Furthermore, starting from the actual shutdown time, under the condition that the shut-down object remains in the shutdown state and the other coolers remain in the operating state of the sampling time before the actual shutdown time, the top oil temperature, ambient temperature, load current, operating status of each cooler group, and operating current of each cooler group are continuously recorded, and the difference between the top oil temperature and the ambient temperature at the same sampling time is taken as the top oil temperature rise; the first sampling time when the cumulative duration from the actual shutdown time reaches the temperature transition time after the cooler shutdown is taken as the temperature transition end time.

[0075] Before the end of the temperature transition, if the original temperature protection and cooling control do not issue a cooler commissioning command, when the operating status of any group of coolers changes, the operating status of any group of coolers is inconsistent with the operating current, or the continuous acquisition of top oil temperature, ambient temperature or load current is interrupted, the shutdown evaluation is stopped, a resumption command is issued to the shutdown object, and the shutdown control result is recorded as resumption of operation.

[0076] Furthermore, taking the end of the temperature transition as the starting point of the interval, a continuous sampling period of the same length as the temperature transition time after the cooler stops is selected along the increasing direction of the sampling time as the shutdown evaluation interval. When the shutdown object in the shutdown evaluation interval remains in the shutdown state, the other coolers remain in the operating state of the sampling time before the actual shutdown time, the operating state of each cooler is consistent with the operating current, and there are no less than three sampling values ​​of top oil temperature and load current, the top oil temperature and load current in the shutdown evaluation interval are respectively fitted with least squares straight lines. The slope of the fitted straight line of top oil temperature is taken as the actual rate of change of top oil temperature, and the slope of the fitted straight line of load current is taken as the actual rate of change of load current.

[0077] When the original temperature protection and cooling control do not issue a cooler commissioning command, and the operating status of any group of coolers changes within the shutdown evaluation period, the operating status of any group of coolers is inconsistent with the operating current, the continuous acquisition of top oil temperature or load current is interrupted, or the top oil temperature sampling value or load current sampling value is less than three, a resumption commissioning command is issued to the shutdown object, and the shutdown control result is recorded as resumption commissioning.

[0078] When the actual top oil temperature change rate is not greater than zero and the actual load current change rate is not greater than zero, the shutdown object is kept in a shutdown state, and the shutdown control result is recorded as "maintained shutdown"; when the actual top oil temperature change rate is greater than zero or the actual load current change rate is greater than zero, a restart command is issued to the shutdown object, and the shutdown control result is recorded as "restart".

[0079] It should be noted that if the actual top oil temperature change rate is not greater than zero, it means that the top oil temperature remains unchanged or continues to decrease within the shutdown evaluation period; if the load current change rate is not greater than zero, it means that the load current does not show an upward trend within the shutdown evaluation period; if both the actual top oil temperature change rate and the load current change rate meet the shutdown conditions, the operating state after reducing one set of coolers is maintained; if either change rate does not meet the shutdown conditions, the cooling capacity of the shutdown object is restored.

[0080] Furthermore, after the actual shutdown of the target transformer and the completion of the shutdown evaluation, the transformer cooling operation data is read backward from the sampling time before the actual shutdown time. The data is read continuously while each group of coolers maintains its pre-shutdown operating state and the operating state is consistent with the operating current, until the operating state of any group of coolers changes, the operating state is inconsistent with the operating current, or the data is read to the starting sampling time of the transformer cooling operation data. The continuously read sampling period is taken as the continuous operating interval before the shutdown. The operating state of each group of coolers at the sampling time before the actual shutdown time is taken as the operating state of each group of coolers before the shutdown.

[0081] The continuous sampling period from the actual shutdown time to the end of the shutdown evaluation interval is taken as the post-shutdown recording interval. The shutdown object, the actual shutdown time, the operating status of each group of coolers before shutdown, as well as the top oil temperature rise, load current, operating status of each group of coolers, and operating current of each group of coolers in the continuous operating interval before shutdown and the post-shutdown recording interval are recorded together to form a single group of cooler shutdown record. If no shutdown control command is issued, shutdown execution fails, or the temperature transition process and shutdown evaluation interval are terminated due to changes in operating status, inconsistency between operating status and operating current, or interruption of continuous acquisition, only shutdown control results are formed, and no single group of cooler shutdown record is formed.

[0082] It should also be noted that the original temperature protection and cooling control of the oil-immersed transformer continue to operate during the screening of shutdown targets, temperature transition after cooler shutdown, and shutdown evaluation. The control priority of the original temperature protection and cooling control is higher than that of active energy-saving shutdown. When the original temperature protection or cooling control issues a cooler commissioning command, the active energy-saving shutdown evaluation is terminated, and the cooler commissioning command is executed. When the shutdown target is restored to operation, the shutdown control result is recorded as restored to operation. When the shutdown target is not restored to operation, the shutdown control result is recorded as shutdown evaluation terminated.

[0083] S4. Update the operating status and number of cooler groups based on the shutdown control results. Associate the shutdown record of a single cooler group with the corresponding sampling period record in the transformer cooling operation data and update the valid shutdown records in each processing category accordingly. When re-executing the shutdown object screening, match the temperature transition time and temperature rise rate difference after the cooler shutdown according to the current load current. Continuously execute the shutdown object screening and shutdown judgment until the active energy-saving shutdown is no longer executed. The operating status and number of cooler groups when the active energy-saving shutdown is stopped are taken as the energy-saving control result of the transformer cooling equipment.

[0084] Furthermore, the shutdown control results are read, and the operating status and operating current of each group of coolers are read after the shutdown control results are formed.

[0085] When the shutdown control result is to maintain shutdown, not execute shutdown, or shutdown execution failure, the sampling time when the shutdown control result is formed is taken as the operation status confirmation time. When the shutdown control result is to resume operation, the operation status and operating current of each group of coolers are continuously read after the resumption command is issued until the cooling control loop feedbacks the end of the resumption command execution. The first sampling time after the end of the resumption command execution is taken as the operation status confirmation time. When the shutdown control result is shutdown evaluation termination, the operation status and operating current of each group of coolers are continuously read after the original temperature protection or cooling control of the oil-immersed transformer issues the cooler operation command until the cooling control loop feedbacks the end of the cooler operation command execution. The first sampling time after the end of the cooler operation command execution is taken as the operation status confirmation time.

[0086] When the operating status of each cooler group is consistent with the operating current at the time of operating status confirmation, the operating status of each cooler group at the time of operating status confirmation is used as the updated operating status of each cooler group, and the actual number of cooler groups in operation is counted to obtain the updated number of cooler groups in operation; the updated operating status of each cooler group and the updated number of cooler groups in operation are associated and stored with the sampling record at the time of operating status confirmation in the transformer cooling operation data.

[0087] When the shutdown control result is to maintain shutdown, the shutdown object is in a shutdown state at the time of operation status confirmation, and the operating current of each cooling fan motor in the shutdown object is non-existent, and the operating current of the oil pump motor is also non-existent when the oil pump is set; when the shutdown control result is to resume operation or the shutdown evaluation is terminated, the shutdown object is in an operation state at the time of operation status confirmation, and the operating current of each cooling fan motor in the shutdown object is present, and the operating current of the oil pump motor is also present when the oil pump is set; when the shutdown control result is not to execute shutdown or shutdown execution fails, the number of cooler operating groups is updated according to the actual operating status of each group of coolers at the time of operation status confirmation.

[0088] When the operating status of any group of coolers is inconsistent with the operating current at the time of operation status confirmation, and the shutdown control result is to maintain shutdown but the shutdown object is not in a shutdown state, or the shutdown control result is to restore operation or terminate the shutdown evaluation but the shutdown object is not in a commissioning state, the operating status of each group of coolers and the number of cooler operating groups will not be updated; the time of operation status confirmation, the shutdown control result, the cooler whose operating status is inconsistent with the operating current, the corresponding cooler's operating status and operating current will be associated and recorded to form a transformer cooling equipment operation abnormality record, and active energy-saving shutdown will no longer be executed, and the cooler operation abnormality will be handled in accordance with the original temperature protection and cooling control of oil-immersed transformers.

[0089] It should be noted that when updating the operating status and number of operating coolers for each group, the actual operating conditions, characterized by both cooling control loop feedback and operating current, should be used as the standard. This is to avoid making the next shutdown judgment based on the cooler operating status before the command was executed after a shutdown command, a resumption command, or the intervention of the original cooling control.

[0090] Furthermore, when the shutdown object is actually shut down and the shutdown evaluation is completed, forming a single group of cooler shutdown records, the single group of cooler shutdown records are associated and stored with the sampling records in the continuous operation interval before shutdown and the recording interval after shutdown in the transformer cooling operation data. According to the operating status of each group of coolers before shutdown and the shutdown object, the single group of cooler shutdown records are classified into the matching processing category.

[0091] The newly formed single-group cooler shutdown records are processed to sequentially form a pre-shutdown load current reference range, a pre-shutdown load current fluctuation range, and a post-shutdown observation range. When the conditions for forming the pre-shutdown load current reference range, the conditions for forming the post-shutdown observation range, and the piecewise fitting conditions are all met, the top oil temperature rise within the post-shutdown observation range is piecewise fitted to obtain the temperature transition time after the cooler shutdown. Based on the temperature transition time after the cooler shutdown, a pre-shutdown temperature rise rate calculation range and a post-shutdown temperature rise rate calculation range are formed respectively. When the two temperature rise rate calculation ranges meet the temperature rise rate calculation conditions, a temperature rise rate difference is formed. The post-shutdown temperature transition time, the temperature rise rate difference, and the pre-shutdown load current fluctuation range are associated and stored, and added to the valid shutdown records of the matching processing category. When the conditions for forming the pre-shutdown load current reference range, the post-shutdown observation range, the piecewise fitting conditions, or the temperature rise rate calculation conditions are not met, the single-group cooler shutdown record is retained, but it is not added to the valid shutdown records.

[0092] During the next shutdown target screening, load matching shutdown records are selected from the updated valid shutdown records based on the current load current, and the median value of the temperature transition time and the median value of the temperature rise rate difference after the cooler shutdown are recalculated. When the median value of the temperature rise rate difference is greater than zero, the corresponding median value is used for shutdown target matching; otherwise, the corresponding cooler is not considered as a candidate shutdown target.

[0093] Furthermore, when the shutdown control result is to maintain shutdown, and the updated operating status of each group of coolers is consistent with the operating current, the updated operating status of each group of coolers is taken as the current operating status of each group of coolers. The temperature transition time and temperature rise rate difference after the cooler shutdown are rematched, and the shutdown target screening, current change rate calculation, and shutdown judgment are re-executed. If the re-formed shutdown control result is still to maintain shutdown, the operating status of each group of coolers and the number of cooler operating groups are updated again, and the shutdown target screening and shutdown judgment are continued. Each active energy-saving shutdown only controls one group of coolers to stop operating.

[0094] When the shutdown control result is no shutdown, shutdown execution failure, resumption of operation, or shutdown evaluation termination, active energy-saving shutdown will no longer be executed; when the operating status and operating current of any group of coolers are inconsistent during the cyclic execution process, a record of the sampling time, cooler, operating status, and operating current inconsistency will be generated, forming a transformer cooling equipment operation abnormality record, and active energy-saving shutdown will no longer be executed; when the original temperature protection or cooling control of the oil-immersed transformer issues a cooler commissioning command, active energy-saving shutdown will be terminated, and the cooler commissioning command issued by the original temperature protection or cooling control will be executed.

[0095] It should also be noted that after each shutdown, the temperature transition time and temperature rise rate difference after the shutdown of the coolers are rematched based on the actual operating combination after reducing one set of coolers, and the remaining cooling capacity is reassessed to determine whether it meets the conditions for continued shutdown, so as to avoid continuously stopping multiple sets of coolers before obtaining feedback on the temperature change after reducing one set of coolers.

[0096] Furthermore, after the active energy-saving shutdown is stopped, if no abnormal operation record of the transformer cooling equipment is formed in the current cycle of the active energy-saving shutdown, the confirmation time of the current cycle's operating status is taken as the sampling time of the energy-saving control result. The operating status of each group of coolers at the sampling time of the energy-saving control result is taken as the operating status of each group of coolers when the active energy-saving shutdown is stopped. The number of cooler groups actually running at the sampling time of the energy-saving control result is counted to obtain the number of cooler groups running when the active energy-saving shutdown is stopped. The operating status of each group of coolers and the number of cooler groups running when the active energy-saving shutdown is stopped are taken as the energy-saving control result of the transformer cooling equipment.

[0097] When the current cycle of active energy-saving shutdown generates a record of transformer cooling equipment operation abnormality, the sampling time when the operating status and operating current of each group of coolers are consistent before the abnormality occurs is taken as the sampling time of the energy-saving control result. The operating status and number of cooler groups at the sampling time of the energy-saving control result are taken as the operating status and number of cooler groups that can be confirmed when active energy-saving shutdown is stopped, and the energy-saving control result of the transformer cooling equipment is formed. At the same time, the record of transformer cooling equipment operation abnormality is taken as the termination record of active energy-saving shutdown, and the original temperature protection and cooling control of the oil-immersed transformer continue to handle the cooler operation abnormality.

[0098] It should also be noted that, in order to verify that the temperature transition time after the cooler is shut down can be determined according to the change process of the top oil temperature after the shutdown of a single cooler, and to verify that the shutdown control result can be dynamically formed according to the expected rate of change of top oil temperature after shutdown, the actual rate of change of top oil temperature, and the update process of the number of cooler operating groups, a simulation scenario for temperature monitoring and energy-saving control of transformer cooling equipment is constructed. In the simulation scenario, transformer cooling operation data is collected during the shutdown process of a single cooler group and the active energy-saving shutdown process of the same oil-immersed transformer. Top oil temperature, ambient temperature, load current, operating status of each cooler group, and operating current of each cooler group are recorded according to a unified sampling clock. Top oil temperature rise is calculated based on top oil temperature and ambient temperature. Single cooler shutdown records are extracted from the transformer cooling operation data. Candidate segment boundaries are set within the observation interval after shutdown, and segment fitting errors are generated based on the top oil temperature rise fitting results before and after the candidate segment boundaries. This results in the temperature transition end time, the temperature transition time after cooler shutdown, and the temperature rise rate difference. Then, based on the current operating status of each cooler group and the current load current, the temperature transition time and temperature rise rate difference after cooler shutdown are matched from the effective shutdown records. Combined with the expected top oil temperature change rate after shutdown, the actual top oil temperature change rate, and the actual load current change rate, a shutdown control result is formed, and the number of operating cooler groups is updated based on the shutdown control result.

[0099] Figure 5 This is used to demonstrate the process of how the temperature rise of the top layer oil changes with the sampling time after a single cooler is shut down, and how the end time of the temperature transition is determined by piecewise fitting. Figure 5 In the graph, the horizontal axis represents the sampling duration, and the vertical axis represents the top oil temperature rise. The top oil temperature rise curve represents the process of top oil temperature rise change based on the top oil temperature and ambient temperature. The fitted straight line for the transition section represents the fitted result of the top oil temperature rise from the actual shutdown time to the end of the temperature transition. The fitted straight line for the end of the transition section represents the fitted result of the top oil temperature rise after the end of the temperature transition. The two vertical marker lines represent the actual shutdown time and the end of the temperature transition, respectively. Figure 5It can be seen that after the actual shutdown of the cooler, the sampled values ​​of the top oil temperature rise before and after the end of the temperature transition form the transition segment and the transition end segment, respectively. The fitted lines of the transition segment and the transition end segment show different trends. This indicates that the temperature transition time after the cooler shutdown originates from the piecewise fitting results of the actual change in the top oil temperature rise, representing the temperature rise change segments before and after the segment boundaries, and providing a time basis for determining the calculation intervals of the temperature rise rate before and after shutdown.

[0100] Figure 6 This is used to demonstrate the relationship between the expected rate of change of top-layer oil temperature after shutdown, the actual rate of change of top-layer oil temperature, and the number of cooler operating groups under the sequence of shutdown control results. Figure 6 In the diagram, the horizontal axis represents the order in which shutdown control results are generated, the left vertical axis represents the rate of change of top-layer oil temperature, and the right vertical axis represents the number of cooler operating groups. The predicted rate of change of top-layer oil temperature after shutdown represents the predicted trend based on the difference between the current rate of change of top-layer oil temperature and the temperature rise rate corresponding to the shutdown object. The actual rate of change of top-layer oil temperature represents the actual trend formed by fitting the top-layer oil temperature within the shutdown evaluation interval. The number of cooler operating groups curve represents the actual number of operating coolers updated after each shutdown control result is generated. The zero-value reference line is used to distinguish whether the top-layer oil temperature is trending upward. Figure 6 It can be seen that when the shutdown control results were formed in the first two instances, neither the expected rate of change of the top-level oil temperature after shutdown nor the actual rate of change of the top-level oil temperature was higher than the zero reference line. The shutdown control result was to maintain shutdown, and the number of cooler operating groups was gradually updated from four to three, and then to two, following the shutdown control results. When the shutdown judgment was made again, the expected rate of change of the top-level oil temperature after shutdown was higher than the zero reference line, indicating that the top-level oil temperature would rise after further reducing the number of cooler operating groups. Therefore, the shutdown control result was not to execute shutdown, and the number of cooler operating groups remained unchanged. It can be seen that this invention controls only one group of coolers to stop operating each time for proactive energy-saving shutdown, and updates the operating status, number of cooler operating groups, and effective shutdown records of each group of coolers after the shutdown control result is formed. This allows the shutdown target selection and shutdown judgment to be executed successively according to changes in actual cooling capacity, thereby forming an energy-saving control result for transformer cooling equipment that is adapted to the actual cooling capacity.

[0101] This embodiment also provides a temperature monitoring and energy-saving control system for transformer cooling equipment, including: The cooling monitoring module is used to collect transformer cooling operation data, generate top oil temperature rise based on top oil temperature and ambient temperature, and count the number of operating cooler groups based on the operating status and operating current of each cooler group.

[0102] The shutdown analysis module is used to extract shutdown records of a single group of coolers from the transformer cooling operation data. It classifies the processing categories according to the operating status of each group of coolers before shutdown and the shutdown object. It performs segmented fitting on the temperature rise change of the top oil after shutdown to form the temperature transition time, temperature rise rate difference and effective shutdown records after the cooler shutdown.

[0103] The energy-saving control module is used to screen shutdown targets and determine whether to shut down based on the current operating status of each group of coolers and the temperature transition time and temperature rise rate difference after the current load current matches the cooler shutdown. It generates shutdown control results based on the actual top oil temperature change rate and the actual load current change rate after shutdown, and generates a shutdown record for a single group of coolers when the shutdown evaluation is completed.

[0104] The cyclic update module is used to update the operating status of each group of coolers, the number of cooler operating groups, and the valid shutdown records in each processing category based on the shutdown control results. It cyclically performs shutdown object screening and shutdown judgment until active energy-saving shutdown is no longer executed, thus forming the energy-saving control results of the transformer cooling equipment.

[0105] In summary, this invention: by segmenting and fitting the top oil temperature rise after shutdown and comparing the temperature rise rate over equal durations before and after shutdown, it determines the segmented positions of the top oil temperature rise change after the cooler shutdown, and characterizes the temperature rise changes corresponding to different cooler operating combinations and shutdown objects; by matching the current operating status of each group of coolers and the current load current with the shutdown characteristics, combined with the judgment of the expected top oil temperature change after shutdown, shutdown evaluation, and updating of effective shutdown records, it achieves group-by-group screening of shutdown objects and dynamic confirmation of shutdown conditions, forming an energy-saving control result for transformer cooling equipment that is adapted to the actual cooling capacity.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for temperature monitoring and energy-saving control of transformer cooling equipment, characterized in that, include: Collect transformer cooling operation data, calculate top oil temperature rise based on top oil temperature and ambient temperature, and count the number of operating cooler groups based on the operating status and operating current of each cooler group; Extract single-group cooler shutdown records from transformer cooling operation data, process them according to the operating status of each group of coolers before shutdown and the shutdown object, and perform piecewise fitting on the top oil temperature rise change after shutdown to form the temperature transition time and temperature rise rate difference after cooler shutdown. Based on the current operating status of each group of coolers and the difference in temperature transition time and temperature rise rate after the cooler is shut down, the shutdown targets are screened and it is determined whether to shut down, and after the temperature transition time after the cooler is shut down, the shutdown control result is formed based on the actual top oil temperature change rate and the actual load current change rate. When the shutdown target is actually shut down and the shutdown evaluation is completed, a single group of coolers shutdown record is formed. Based on the shutdown control results, the operating status and number of operating coolers for each group are updated. The shutdown record of a single cooler group is associated with the corresponding sampling period record in the transformer cooling operation data and stored accordingly. Based on this, the valid shutdown records in each processing category are updated. When the shutdown object screening is re-executed, the temperature transition time and temperature rise rate difference after the cooler shutdown are matched according to the current load current. The shutdown object screening and shutdown judgment are cyclically executed until the active energy-saving shutdown is no longer executed. The operating status and number of operating coolers for each group when the active energy-saving shutdown is stopped are taken as the energy-saving control result of the transformer cooling equipment.

2. The method for temperature monitoring and energy-saving control of transformer cooling equipment as described in claim 1, characterized in that, The collected transformer cooling operation data includes: During the operation of the oil-immersed transformer, the top oil temperature, ambient temperature and load current are collected, the operating status of each group of coolers is read, the operating current of each cooling fan motor in each group of coolers is collected, and the operating current of the corresponding oil pump motor is collected when the forced oil circulation cooling method is adopted. The transformer cooling operation data is generated by storing the top oil temperature, ambient temperature, load current, operating status of each group of coolers, and operating current of each group of coolers at the same sampling time according to a unified sampling clock.

3. The method for temperature monitoring and energy-saving control of transformer cooling equipment as described in claim 2, characterized in that, The process of determining the top oil temperature rise based on the top oil temperature and ambient temperature, and counting the number of operating cooler groups based on the operating status and operating current of each cooler group, includes: The difference between the top oil temperature and the ambient temperature at the same sampling time is taken as the top oil temperature rise; Based on the operating status of each group of coolers, the operating current of each cooling fan motor, and the operating current of the oil pump motor when using forced oil circulation cooling, determine whether each group of coolers is actually running. When the operating status and operating current of each group of coolers are consistent, count the number of coolers actually running to obtain the number of cooler operating groups.

4. The method for temperature monitoring and energy-saving control of transformer cooling equipment as described in claim 2 or 3, characterized in that, The process of extracting single-group cooler shutdown records from transformer cooling operation data, and processing them according to the operating status of each group of coolers before shutdown and the object being shut down, includes: The operating status and operating current of each group of coolers are compared according to the sampling time. When only one group of coolers changes from the operating state to the shutdown state between two adjacent sampling times, the operating current of each cooling fan motor in the shutdown cooler changes from present to absent, the operating current of the oil pump motor changes from present to absent when the forced oil circulation cooling method is used, and the operating status and the presence or absence of the operating current of the other groups of coolers remain unchanged, the shutdown object and the actual shutdown time are determined. The sampling periods for each group of coolers maintaining their pre-shutdown operating state are continuously read backwards from the sampling time preceding the actual shutdown time to form a continuous operating interval before shutdown. The sampling periods for each group of coolers maintaining their post-shutdown operating state are continuously read backwards from the actual shutdown time to form a continuous operating interval after shutdown. The transformer cooling operation data of the continuous operating interval before shutdown, the actual shutdown time, the continuous operating interval after shutdown, the shutdown object, and the corresponding sampling periods are linked and recorded to form a single group of cooler shutdown record. The shutdown records of single groups of coolers with the same operating status before shutdown and the same shutdown target are grouped into the same processing category.

5. The method for temperature monitoring and energy-saving control of transformer cooling equipment as described in claim 4, characterized in that, The step of segmenting and fitting the temperature rise change of the top oil after shutdown to form the temperature transition time and temperature rise rate difference after the cooler is shut down includes: Six consecutive sampling times before the actual shutdown time are selected from the continuous operating interval before the shutdown to form the load current reference interval before the shutdown. The load current fluctuation range before the shutdown is formed based on the minimum and maximum values ​​of the load current within the load current reference interval before the shutdown. When the load current at the actual shutdown time is within the range of the load current fluctuation before shutdown, the load current in the continuous operation interval after shutdown is read from the actual shutdown time, and the observation interval after shutdown is determined according to the sampling time when the load current first exceeds the range of the load current fluctuation before shutdown. Candidate segment boundaries are set within the observation interval after shutdown. The top oil temperature rise on the front and back sides of each candidate segment boundary is fitted with a least square straight line. The piecewise fitting error is formed based on the sum of squared residuals of the two fitting segments. The sampling time of the first top oil temperature rise sample value on the back side of the candidate segment boundary with the smallest piecewise fitting error is taken as the end time of temperature transition. The duration between the actual shutdown time and the end time of temperature transition is taken as the temperature transition time after the cooler is shut down. The temperature rise rate calculation period is defined by the temperature transition time after the cooler is shut down, and the temperature rise rate difference is formed based on the temperature rise change of the top oil before and after shutdown.

6. The method for temperature monitoring and energy-saving control of transformer cooling equipment as described in claim 5, characterized in that, The method of generating a temperature rise rate difference based on the change in top-layer oil temperature before and after shutdown includes: Using the sampling time preceding the actual shutdown time as the end point of the interval, a continuous sampling period of the same length as the temperature transition time after the cooler shutdown is selected from the continuous operation interval before shutdown to form the temperature rise rate calculation interval before shutdown; using the end time of the temperature transition as the start point of the interval, a continuous sampling period of the same length as the temperature transition time after the cooler shutdown is selected from the observation interval after shutdown to form the temperature rise rate calculation interval after shutdown. Least squares linear fitting was performed on the top oil temperature rise within the calculation intervals of the temperature rise rate before and after shutdown, and the difference between the top oil temperature rise rate after shutdown and the top oil temperature rise rate before shutdown was taken as the temperature rise rate difference. The temperature transition time, temperature rise rate difference, and load current fluctuation range before shutdown of the cooler are associated with the operating status of each group of coolers and the shutdown object before shutdown, and stored to form a valid shutdown record of the corresponding processing category.

7. The method for temperature monitoring and energy-saving control of transformer cooling equipment as described in claim 6, characterized in that, The process of screening for shutdown targets and determining whether they are shut down includes: Based on the current operating status of each group of coolers and the coolers currently in operation, select load matching shutdown records from the valid shutdown records of the corresponding processing category. The current load current is within the fluctuation range of the load current before shutdown. Arrange the temperature transition time and temperature rise rate difference after the shutdown of the coolers in the load matching shutdown records according to the values ​​and determine the median value. Select the coolers currently in operation with a median value of temperature rise rate difference that is greater than zero as candidate shutdown objects. The candidate shutdown object with the smallest temperature rise rate difference is selected as the shutdown object; when the temperature rise rate difference of multiple candidate shutdown objects is the same, the candidate shutdown object with the shortest temperature transition time after the cooler is shut down is selected as the shutdown object; when the temperature rise rate difference and the temperature transition time after the cooler is shut down are the same, under the condition that the power supply voltage and power supply phase system of each candidate shutdown object are the same, the current operating current of each cooling fan motor in each candidate shutdown object is summed, and when the forced oil circulation cooling method is used, the current operating current of the oil pump motor is summed together to obtain the total value of the current operating current, and the candidate shutdown object with the largest total value of the current operating current is selected as the shutdown object; A calculation interval for the current rate of change is selected, with the current sampling time as the endpoint and the same duration as the temperature transition time after the cooler is shut down. Least squares linear fitting is performed on the top oil temperature rise, ambient temperature, and load current to form the current rate of change of top oil temperature rise, the current rate of change of ambient temperature, and the current rate of change of load current. The sum of the current rate of change of top oil temperature rise and the current rate of change of ambient temperature is taken as the current rate of change of top oil temperature. The sum of the difference between the current rate of change of top oil temperature and the temperature rise rate corresponding to the shut-down object is taken as the expected rate of change of top oil temperature after shutdown. When both the current rate of change of load current and the expected rate of change of top oil temperature after shutdown are not greater than zero, a shutdown control command is issued to the shut-down object; otherwise, shutdown is not executed.

8. The method for temperature monitoring and energy-saving control of transformer cooling equipment as described in claim 7, characterized in that, The shutdown control result is formed based on the actual top-layer oil temperature change rate and the actual load current change rate, and a single-group cooler shutdown record is generated when the shutdown object is actually shut down and the shutdown evaluation is completed, including: After issuing the shutdown control command, the operating status and operating current of the shutdown object are continuously read. The sampling time when the shutdown object is first in the shutdown state and all operating currents are absent is taken as the actual shutdown time. The first sampling time when the cumulative duration from the actual shutdown time reaches the temperature transition time after the cooler is shut down is taken as the end time of temperature transition. A shutdown evaluation interval with the same duration as the temperature transition time after the cooler is shut down is selected, using the end time of the temperature transition as the starting point. Least squares linear fitting is performed on the top oil temperature and load current within the shutdown evaluation interval to form the actual top oil temperature change rate and the actual load current change rate. When both the actual top oil temperature change rate and the actual load current change rate are not greater than zero, the shutdown control result is recorded as "maintain shutdown". When either the actual top oil temperature change rate or the actual load current change rate is greater than zero, a restart command is issued to the shutdown object, and the shutdown control result is recorded as "restart". After the shutdown of the target device is actually shut down and the shutdown evaluation is completed, the continuous sampling period during which each group of coolers maintained its pre-shutdown operating state before the actual shutdown time is taken as the pre-shutdown continuous operating interval, and the continuous sampling period from the actual shutdown time to the end of the shutdown evaluation interval is taken as the post-shutdown recording interval. The transformer cooling operation data of the shutdown target, the actual shutdown time, the operating state of each group of coolers before shutdown, and the continuous operating interval before shutdown and the post-shutdown recording interval are linked and recorded to form a single group of cooler shutdown record; During the temperature transition and shutdown evaluation period after the cooler is shut down, when the original temperature protection or cooling control of the oil-immersed transformer issues a cooler commissioning command, the shutdown evaluation is terminated and the cooler commissioning command is executed.

9. The method for temperature monitoring and energy-saving control of transformer cooling equipment as described in claim 8, characterized in that, The cycle of screening and determining shutdown targets continues until proactive energy-saving shutdown is no longer performed. The operating status of each group of coolers and the number of operating cooler groups at the time of cessation of proactive energy-saving shutdown are used as the energy-saving control results for the transformer cooling equipment, including: After each shutdown control result is generated, the operating status and operating current of each group of coolers are read. When the operating status and operating current of each group of coolers are consistent, the operating status and number of cooler groups in operation of each group of coolers are updated. The newly formed single-group cooler shutdown record is assigned to the matching processing category, and the valid shutdown record of the corresponding processing category is updated after the temperature transition time and temperature rise rate difference after the cooler shutdown is formed. When the shutdown control result is to maintain shutdown, the updated operating status of each group of coolers is used as the current operating status of each group of coolers. Based on the current load current, the temperature transition time and temperature rise rate difference after the cooler shutdown are rematched from the updated valid shutdown records. The shutdown object screening and shutdown judgment are re-executed. Each active energy-saving shutdown only controls one group of coolers to stop operating. When the shutdown control result is not to maintain shutdown, the operating status of any group of coolers is inconsistent with the operating current, or the original temperature protection or cooling control of the oil-immersed transformer issues a cooler commissioning command, the active energy-saving shutdown is stopped, and the operating status of each group of coolers and the number of cooler groups in operation at the time of stopping the active energy-saving shutdown are taken as the energy-saving control result of the transformer cooling equipment.

10. A temperature monitoring and energy-saving control system for transformer cooling equipment, based on the temperature monitoring and energy-saving control method for transformer cooling equipment according to any one of claims 1 to 9, characterized in that, include: The cooling monitoring module is used to collect transformer cooling operation data, generate top oil temperature rise based on top oil temperature and ambient temperature, and count the number of operating cooler groups based on the operating status and operating current of each group of coolers. The shutdown analysis module is used to extract single-group cooler shutdown records from transformer cooling operation data. It classifies the processing categories according to the operating status of each group of coolers before shutdown and the shutdown object. It performs segmented fitting on the top oil temperature rise change after shutdown to form the temperature transition time, temperature rise rate difference and effective shutdown records after cooler shutdown. The energy-saving control module is used to screen shutdown targets and determine whether to shut down based on the current operating status of each group of coolers and the difference in temperature transition time and temperature rise rate after the current load current is matched with the current cooler shutdown. It generates shutdown control results based on the actual top oil temperature change rate and the actual load current change rate after shutdown, and generates a single group of cooler shutdown record when the shutdown evaluation is completed. The cyclic update module is used to update the operating status of each group of coolers, the number of cooler operating groups, and the valid shutdown records in each processing category based on the shutdown control results. It cyclically performs shutdown object screening and shutdown judgment until active energy-saving shutdown is no longer executed, thus forming the energy-saving control results of the transformer cooling equipment.

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