Self-diagnosis method for operation accuracy of temperature measuring device of power transformation equipment

Abstract

The invention relates to a self-diagnosis method for operation accuracy of a temperature measuring device of power transformation equipment, the temperature measuring device diagnosed by the method comprises three groups of oil tank channels for independently measuring temperature and an environment channel for measuring environment temperature, and the method comprises the following steps: S1, calculating a temperature difference value of measured temperatures of any two oil tank channels, and carrying out first-step judgment; s2, if all the obtained difference values meet the requirements, executing S3; otherwise, indicating value faults exist; s3, the measured temperature calculation value corresponding to each oil tank channel is calculated, the deviation increment of the measured temperature calculation values of any two oil tank channels is obtained, and second-stage judgment is carried out; s4, if any oil tank channel does not meet the requirement, indicating value faults exist; s5, calculating an assignment value corresponding to each channel, determining a deviation value, and carrying out third-stage judgment; and S6, if the assignment deviation value of any oil tank channel does not meet the requirement, indicating value faults exist in the measuring device. Compared with the prior art, the method has the advantages of high self-diagnosis accuracy, high purposiveness and the like.

Description

Technical Field

[0001] The invention relates to the technical field of substation equipment detection, and in particular to a self-diagnosis method for the operating accuracy of a temperature measuring device of a substation equipment. Background Art

[0002] During normal operation, the internal winding coils and cores of oil-immersed substation equipment will heat up due to the current, and the temperature of the substation equipment directly affects the service life of the substation equipment. GB / T 1094.7-2016 "Load Guidelines for Oil-Immersed Power Transformers" clearly states that "if the hot spot temperature of the transformer is 6°C higher than the rated value, its rated life is halved"; therefore, reliable measurement of the temperature of the substation equipment is of great value for diagnosing the insulation status of the substation equipment, and can timely warn of potential faults of the substation equipment. It is also of great significance to the control of the insulation life of the substation equipment.

[0003] The transformer temperature measuring device is a thermal protection device that monitors the top oil temperature and winding hot spot temperature of oil-immersed substation equipment in real time, and provides cooling system switching signals and over-temperature alarm (tripping) signals based on the measured temperatures. It is of great significance for fault early warning of oil-immersed substation equipment and preventing further expansion of equipment failures. It is an important component to ensure the safe operation of the power grid.

[0004] When the pointer thermometer or (and) remote signal device in the temperature measuring device indicates an out-of-tolerance value, the transformer protection system will falsely (or leak) alarm due to the out-of-tolerance value of the pointer thermometer; if the indication of the on-site pointer thermometer deviates greatly from the indication of the back-end remote signal device, it will be impossible to determine whether it is the fault of the temperature measuring device itself or the fault inside the substation equipment, which greatly increases the workload of equipment operation and maintenance, and may also cause more serious accidents due to missing the best time for maintenance. Therefore, providing a temperature measuring device with an operation accuracy self-diagnosis function is of great practical significance to ensure the safe and stable operation of oil-immersed substation equipment and the safety of the power grid. Summary of the invention

[0005] The purpose of the present invention is to provide a self-diagnosis method for the operating accuracy of a temperature measuring device of a substation equipment in order to overcome the defect that the operating accuracy of the temperature measuring device in the above-mentioned prior art cannot be detected in real time.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A self-diagnosis method for the operation accuracy of a temperature measuring device of a transformer substation, wherein the temperature measuring device diagnosed by the method includes three groups of oil tank channels for independent temperature measurement and an environmental channel for measuring the ambient temperature, and the method includes the following steps:

[0008] S1: Obtain the real-time temperature measured by each channel of the temperature measuring device, calculate the temperature difference between the temperatures measured by any two fuel tank channels, and compare the obtained temperature difference with the allowable error limit of the indication;

[0009] S2: If the obtained differences all meet the requirements, execute S3; if there are differences that do not meet the requirements, the measuring device has an indication fault;

[0010] S3: Combine the measured temperature of each fuel tank channel with the measured temperature of the environment channel, calculate the measured temperature calculation value corresponding to each fuel tank channel, obtain the deviation increment of the measured temperature calculation values ​​of any two fuel tank channels, and determine the indication of each fuel tank channel;

[0011] S4: If any of the fuel tank channels does not meet the requirements, the measuring device has an indication fault; if all three groups of fuel tank channels meet the requirements, execute step S5;

[0012] S5: Calculate the corresponding assigned value according to the measured temperature calculation value of each fuel tank channel, further determine the deviation of the related assigned value of the same fuel tank channel, and judge the indication of the corresponding fuel tank channel according to the deviation of each fuel tank channel;

[0013] S6: If the assigned deviation of any fuel tank channel does not meet the requirements, the measuring device has an indication fault; if the assigned deviations of the three groups of fuel tank channels all meet the requirements, the operating accuracy of the measuring device meets the requirements.

[0014] Further, the real-time temperature value of the temperature measuring device obtained in S1 is judged, and if the condition is met, S2 is executed. The judgment of the real-time temperature value includes the following steps:

[0015] S11: Obtain the change in the real-time temperature of the three groups of fuel tank channels, and determine whether the change in the temperature of each group of fuel tank channels is less than or equal to 0.1°C per ten minutes; if so, execute S13; otherwise, execute S12;

[0016] S12: Determine whether the change amount of each group of fuel tank channels continuously increases or decreases at a rate less than or equal to 0.3°C per minute, and the duration is greater than 30 minutes; if so, execute S14, otherwise, execute S11;

[0017] S13: Obtain the temperature differences between the three groups of fuel tank channels and determine whether each temperature difference is greater than 5°C; if so, execute S14; otherwise, execute S11;

[0018] S14: Obtain the difference between the real-time temperature and the preset temperature value, and determine whether the difference is greater than or equal to 5°C; if so, the real-time temperature measured by this group meets the conditions; otherwise, execute S11.

[0019] Further, the temperature difference determination of the fuel tank channel in S2 includes the following steps:

[0020] S21: Obtain the temperature difference between any two fuel tank channels. If any temperature difference is greater than twice the allowable error of the indication, the temperature measuring device has an indication fault, and S22 is executed; otherwise, S3 is executed;

[0021] S22: If the two temperature differences associated with any tank channel are greater than twice the allowable error of indication, and the temperature differences of the other two tank channels are less than or equal to the allowable error of indication, then there is an indication fault in the tank channel.

[0022] Furthermore, in S3, the specific steps of judging the indication of each fuel tank channel include:

[0023] For the check tank channel, obtain the deviation increment of the measured temperature calculation values ​​of the other two tank channels, and calculate the absolute value of the difference between the measured temperature of the check tank channel and the measured temperature calculation values ​​of the other two tank channels;

[0024] If the deviation increment of the calculated values ​​of the measured temperatures of the other two tank channels is less than or equal to the repeatability error limit of the calibration tank channel, and the absolute value of the difference between the measured temperature of the calibration tank channel and the calculated values ​​of the measured temperatures of the other two tank channels is greater than the sum of the allowable error of the indication and the repeatability error limit of the corresponding tank channel, then there is an indication fault in the calibration tank channel.

[0025] Furthermore, in S3, the specific steps of obtaining the calculated values ​​of the measured temperatures of each group of fuel tank channels include:

[0026] Obtaining the normal operation indication value T(i, j) array of the fuel tank channel, and the real-time temperature value and ambient temperature of the fuel tank channel obtained by the measuring device;

[0027] Determine the value i from the array of normal operating indication values ​​T(i, j) according to the ambient temperature, and determine the value j from the array of normal operating indication values ​​T(i, j) according to the real-time temperature value of the fuel tank channel;

[0028] According to the values ​​of i and j, take the values ​​T(i1, j1), T(i1, j2), T(i2, j1) and T(i2, j2) from the array of normal operation indication values ​​T(i, j), where i1<=i≤i2, j1<=j≤j2;

[0029] The measured temperature value of the fuel tank channel is calculated based on the taken value.

[0030] Furthermore, the expression of the calculated value of the measured temperature of the fuel tank channel is obtained as follows:

[0031]

[0032] In the formula,

[0033]

[0034] Among them, i1<T H (k)=i≤i2,j1<T J (k)=j≤j2,T J (k) represents the real-time temperature value of the channel, T H (k) represents the ambient temperature, T J (i1, j1), T J (i1, j2), T J (i2, j1) and T J (i2, j2) represents the known value selected from the normal operating value array T(i, j), T JS (k) represents the calculated value of the measured temperature of the tank channel.

[0035] Furthermore, in S5, the specific steps of determining the temperature measuring device failure include:

[0036] Calculating the assigned values ​​associated with the other two groups of fuel tank channels based on the real-time temperature value of the fuel tank channel and the measured temperature calculated values ​​associated with the other two groups of fuel tank channels;

[0037] Calculate the deviation of the oil tank channel according to the assigned value, and compare the deviation with the proportional coefficient of the qualified judgment of the operating accuracy of the temperature measuring device;

[0038] If the deviation of the fuel tank channel is greater than the proportional coefficient for determining the qualified operation accuracy, the corresponding fuel tank channel has an indication fault.

[0039] Furthermore, the expression for assigning the values ​​of one group of fuel tank channels to the other two groups of fuel tank channels is:

[0040]

[0041] Where, T J (k) represents the real-time temperature value of the fuel tank channel to be diagnosed, T AS (k) and T BS (k) represents the calculated value of the measured temperature of the oil tank channel to be diagnosed and the other two groups of oil tank channels, δ1 represents the allowable error limit of the indication of the temperature measuring device, and δ2 and δ3 represent the repeatability error limits corresponding to the oil tank channel to be diagnosed and the other two groups of oil tank channels respectively.

[0042] Furthermore, the specific steps of calculating the deviation of the fuel tank channel according to the assigned value include:

[0043] Calculate the values ​​of the fuel tank channel to be diagnosed and the other two groups of fuel tank channels for multiple measurements, and then add them together;

[0044] The sum of the values ​​assigned to the fuel tank channel to be diagnosed is divided by the number of the values ​​assigned, and the absolute value of the quotient is taken to obtain the deviation of the fuel tank channel to be diagnosed.

[0045] Furthermore, the expression of the deviation of the fuel tank channel to be diagnosed is:

[0046]

[0047] In the formula, and It represents the sum of the values ​​assigned by multiple measurements of the fuel tank channel to be diagnosed and the other two groups of fuel tank channels, and N represents the number of measurements of the fuel tank channel to be diagnosed and a group of fuel tank channels, that is, the corresponding number of values ​​assigned.

[0048] Compared with the prior art, the present invention has the following advantages:

[0049] (1) This scheme adopts a multi-channel measurement and multi-level diagnosis method. The temperature measuring device measures the oil tank temperature through three groups of oil tank channels at the same time, and preliminarily compares the temperature difference between the three groups of oil tank channels; then combines the ambient temperature and the real-time temperature value to determine the corresponding measured temperature calculation value, and judges the repeatability error of each oil tank channel according to the deviation increment of each channel; finally, combined with the repeatability error between channels, each channel is compared with the operating accuracy qualification determination ratio coefficient of the temperature measuring device to complete the multi-level diagnosis of the temperature measuring device. Through redundant measurement and multi-level error judgment of the temperature measuring device, the accuracy of the self-diagnosis method is guaranteed, thereby improving the operating accuracy of the temperature measuring device.

[0050] (2) This scheme analyzes the factors affecting the operating accuracy of the temperature measuring device, such as the laboratory indication error of the temperature measuring device, the error affected by the ambient temperature, and the error affected by the installation conditions, and establishes a normal operating indication parameter matrix for the temperature measuring device. During the self-diagnosis process, the theoretical calculated value of the oil tank is calculated from the pre-established theoretical indication parameter matrix based on the real-time ambient temperature and the measured temperature of the oil tank channel, and the errors of each channel of the temperature measuring device are further determined. The oil tank channel with indication failure can be accurately obtained, which improves the accuracy and positioning of the self-diagnosis of the temperature measuring device and facilitates accurate maintenance of the temperature measuring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A flow chart of a method for self-diagnosis of the operating accuracy of a temperature measuring device provided by the present invention;

[0052] Figure 2 A flow chart of continuously obtaining temperature determination during the self-diagnosis process provided by the present invention;

[0053] Figure 3 A flow chart of the first stage of self-diagnosis provided by the present invention;

[0054] Figure 4 A flow chart of the second stage of self-diagnosis provided by the present invention;

[0055] Figure 5 This is a flow chart of the third stage of self-diagnosis provided by the present invention. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0057] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0059] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0060] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0061] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0062] Example 1

[0063] like Figure 1 As shown, this embodiment provides a self-diagnosis method for the operation accuracy of a temperature measuring device of a substation. The temperature measuring device diagnosed by the method includes three groups of oil tank channels for independent temperature measurement and an environmental channel for measuring the ambient temperature. The method includes the following steps:

[0064] S1: Obtain the real-time temperature measured by each channel of the temperature measuring device, calculate the temperature difference between the temperatures measured by any two fuel tank channels, and compare the obtained temperature difference with the allowable error limit of the indication;

[0065] S2: If the obtained differences all meet the requirements, execute S3; if there are differences that do not meet the requirements, the measuring device has an indication fault;

[0066] S3: Combine the measured temperature of each fuel tank channel with the measured temperature of the environment channel, calculate the measured temperature calculation value corresponding to each fuel tank channel, obtain the deviation increment of the measured temperature calculation values ​​of any two fuel tank channels, and determine the indication of each fuel tank channel;

[0067] S4: If any of the fuel tank channels does not meet the requirements, the measuring device has an indication fault; if all three groups of fuel tank channels meet the requirements, execute step S5;

[0068] S5: Calculate the corresponding assigned value according to the measured temperature calculation value of each fuel tank channel, further determine the deviation of the related assigned value of the same fuel tank channel, and judge the indication of the corresponding fuel tank channel according to the deviation of each fuel tank channel;

[0069] S6: If the assigned deviation of any fuel tank channel does not meet the requirements, the measuring device has an indication fault; if the assigned deviations of the three groups of fuel tank channels all meet the requirements, the operating accuracy of the measuring device meets the requirements.

[0070] Using multi-channel measurement and multi-level diagnosis, the temperature measuring device measures the oil tank temperature through three groups of oil tank channels at the same time, and preliminarily compares the temperature difference between the three groups of oil tank channels; then combines the ambient temperature and real-time temperature value to determine the corresponding measured temperature calculation value, and judges the repeatability error of each oil tank channel according to the deviation increment of each channel; finally, combined with the repeatability error between channels, each channel is compared with the operating accuracy qualification determination ratio coefficient of the temperature measuring device to complete the multi-level diagnosis of the temperature measuring device. Through redundant measurement and multi-level error judgment of the temperature measuring device, the accuracy of the self-diagnosis method is guaranteed, thereby improving the operating accuracy of the temperature measuring device.

[0071] The real-time temperature value of the temperature measuring device obtained in S1 is judged, and if the condition is met, S2 is executed. The judgment of the real-time temperature value includes the following steps:

[0072] S11: Obtain the change in the real-time temperature of the three groups of fuel tank channels, and determine whether the change in the temperature of each group of fuel tank channels is less than or equal to 0.1°C per ten minutes; if so, execute S13; otherwise, execute S12;

[0073] S12: Determine whether the change amount of each group of fuel tank channels continuously increases or decreases at a rate less than or equal to 0.3°C per minute, and the duration is greater than 30 minutes; if so, execute S14, otherwise, execute S11;

[0074] S13: Obtain the temperature differences between the three groups of fuel tank channels and determine whether each temperature difference is greater than 5°C; if so, execute S14; otherwise, execute S11;

[0075] S14: Obtain the difference between the real-time temperature and the preset temperature value, and determine whether the difference is greater than or equal to 5°C; if so, the real-time temperature measured by this group meets the conditions; otherwise, execute S11.

[0076] Because multiple measurements are required every day, in order to improve the continuity of the temperature measuring device's collection, when the self-diagnosis module obtains the measured temperature, the real-time temperature of the fuel tank channel will be continuously read only when the temperature fluctuation is not large and the temperature rises or falls evenly, for subsequent self-diagnosis of the operating accuracy of the temperature measuring device.

[0077] Specifically, the temperature difference judgment of the fuel tank channel in S2 is the first step of diagnosing the temperature measuring device, including the following steps:

[0078] S21: Obtain the temperature difference between any two fuel tank channels. If any temperature difference is greater than twice the allowable error of the indication, the temperature measuring device has an indication fault, and S22 is executed; otherwise, S3 is executed;

[0079] S22: If the two temperature differences associated with any tank channel are greater than twice the allowable error of indication, and the temperature differences of the other two tank channels are less than or equal to the allowable error of indication, then there is an indication fault in the tank channel.

[0080] In S3, the specific steps of judging the indication of each fuel tank channel include:

[0081] For the check tank channel, obtain the deviation increment of the measured temperature calculation values ​​of the other two tank channels, and calculate the absolute value of the difference between the measured temperature of the check tank channel and the measured temperature calculation values ​​of the other two tank channels;

[0082] If the deviation increment of the calculated values ​​of the measured temperatures of the other two tank channels is less than or equal to the repeatability error limit of the calibration tank channel, and the absolute value of the difference between the measured temperature of the calibration tank channel and the calculated values ​​of the measured temperatures of the other two tank channels is greater than the sum of the allowable error of the indication and the repeatability error limit of the corresponding tank channel, then there is an indication fault in the calibration tank channel.

[0083] In S3, the calculated values ​​of the measured temperatures of the fuel tank channels of each group are used for the second step diagnosis of the temperature measuring device. The specific steps of obtaining the calculated values ​​of the measured temperatures include:

[0084] Obtaining the normal operation indication value T(i, j) array of the fuel tank channel, and the real-time temperature value and ambient temperature of the fuel tank channel obtained by the measuring device;

[0085] Determine the value i from the array of normal operating indication values ​​T(i, j) according to the ambient temperature, and determine the value j from the array of normal operating indication values ​​T(i, j) according to the real-time temperature value of the fuel tank channel;

[0086] According to the values ​​of i and j, take the values ​​T(i1, j1), T(i1, j2), T(i2, j1) and T(i2, j2) from the array of normal operation indication values ​​T(i, j), where i1<=i≤i2, j1<=j≤j2;

[0087] The measured temperature value of the fuel tank channel is calculated based on the taken value.

[0088] The expression of the calculated value of the measured temperature of the fuel tank channel is obtained as follows:

[0089]

[0090] In the formula,

[0091]

[0092] Among them, i1<T H (k)=i≤i2,j1<T J (k)=j≤j2,T J (k) represents the real-time temperature value of the channel, T H (k) represents the ambient temperature, T J (i1, j1), T J (i1, j2), T J (i2, j1) and T J (i2, j2) represents the known value selected from the normal operating value array T(i, j), T JS (k) represents the calculated value of the measured temperature of the tank channel.

[0093] In S5, the temperature deviation obtained by the temperature measuring device is compared with the preset operation accuracy qualification determination proportional coefficient. The specific steps of the third step of the temperature measuring device determination include:

[0094] Calculating the assigned values ​​associated with the other two groups of fuel tank channels based on the real-time temperature value of the fuel tank channel and the measured temperature calculated values ​​associated with the other two groups of fuel tank channels;

[0095] Calculate the deviation of the oil tank channel according to the assigned value, and compare the deviation with the proportional coefficient of the qualified judgment of the operating accuracy of the temperature measuring device;

[0096] If the deviation of the fuel tank channel is greater than the proportional coefficient for determining the qualified operation accuracy, the corresponding fuel tank channel has an indication fault.

[0097] The expression for assigning one group of fuel tank channels to the other two groups of fuel tank channels is:

[0098]

[0099] Where, T J (k) represents the real-time temperature value of the fuel tank channel to be diagnosed, T AS (k) and T BS (k) represents the calculated value of the measured temperature of the oil tank channel to be diagnosed and the other two groups of oil tank channels, δ1 represents the allowable error limit of the indication of the temperature measuring device, and δ2 and δ3 represent the repeatability error limits corresponding to the oil tank channel to be diagnosed and the other two groups of oil tank channels respectively.

[0100] The specific steps of calculating the deviation of the fuel tank channel according to the assigned value include:

[0101] Calculate the values ​​of the fuel tank channel to be diagnosed and the other two groups of fuel tank channels for multiple measurements, and then add them together;

[0102] The sum of the values ​​assigned to the fuel tank channel to be diagnosed is divided by the number of the values ​​assigned, and the absolute value of the quotient is taken to obtain the deviation of the fuel tank channel to be diagnosed.

[0103] The expression of the deviation of the fuel tank channel to be diagnosed is:

[0104]

[0105] In the formula, and It represents the sum of the values ​​assigned by multiple measurements of the fuel tank channel to be diagnosed and the other two groups of fuel tank channels, and N represents the number of measurements of the fuel tank channel to be diagnosed and a group of fuel tank channels, that is, the corresponding number of values ​​assigned.

[0106] In combination with the above preferred implementation, this embodiment provides a more specific implementation: a self-diagnosis method for the operation accuracy of a temperature measuring device of a substation, based on a temperature measuring device including three groups of measurement of an oil tank channel, specifically including a pointer thermometer measurement channel, denoted as P J Channel: The measurement channel of the Pt100 sensor is denoted as P A The other set of measurement channels uses Pt100 as the sensor, denoted as P B There is also a set of ambient temperature monitoring channels that use Pt100 as a sensor to measure the ambient temperature, denoted as P H Channel. The self-diagnosis method collects the temperature through three groups of measurement channels and the ambient temperature monitoring channel, and the output analog or digital signal is an online self-diagnosis of the operating accuracy of the temperature measuring device.

[0107] This self-diagnosis requires the use of the judgment thresholds preset in the self-diagnosis module, which include δ1, δ2, δ3, δ4 and δ5; δ1 represents the allowable error limit of the temperature measuring device, which is the product of the temperature measuring device range and the accuracy grade percentage; δ2 represents P J Channel and P A Channel repeatability error limit - P J Channel and P A The standard deviation between the sum of the channel repeatability error limits and 0; δ3 represents P J Channel and P B Channel repeatability error limit - P J Channel and P B The standard deviation between the sum of the repeatability error limits of the channels and 0; δ4 represents P A Channel and P B Channel repeatability error limit - P A Channel and P B The standard deviation between the sum of the repeatability error limits of the channels and 0; δ5 represents the proportional coefficient for determining the qualified operation accuracy of the temperature measuring device, and the default value is the standard deviation between 0 and 1, i.e. 70.7%.

[0108] Real-time temperature values ​​include P J Channel real-time temperature value T J (k); P A Channel real-time temperature value T A (k); P B Channel real-time temperature value T B (k); and ambient temperature value T H (k). Figure 2 As shown, the self-diagnostic transmitter automatically obtains the real-time temperature value and should meet the following requirements:

[0109] (1) The change in the three sets of temperature values ​​at each reading is no more than 0.1°C / 10min; or the temperature is continuously raised or lowered at a rate of no more than 0.3°C / min for more than 30min;

[0110] (2) The difference between the three sets of temperature values ​​read multiple times daily is greater than 5°C;

[0111] (3) The absolute value of the difference between the real-time temperature value TJ(k) and the temperature control switch setting value entered in the basic parameters shall not be less than 5°C.

[0112] By making a preliminary judgment on the difference of the real-time temperature values ​​obtained before the self-diagnosis module continuously collects temperature, the validity of the data used to judge the operating accuracy of the temperature measuring device is guaranteed, thereby improving the accuracy of the self-diagnosis judgment of the temperature measuring device.

[0113] like Figure 3 As shown, the first stage of self-diagnosis of the temperature measuring device includes:

[0114] Calculate the real-time temperature value T of the three groups of oil tank channels of the measuring device J (k), T A (k), T B (k) Temperature difference between them:

[0115] ΔT JA (k) = T J (k)-T A (k)

[0116] ΔT JB (k) = T J (k)-T B (k)

[0117] ΔT AB (k) = T A (k)-T B (k)

[0118] When the absolute value of any temperature difference is greater than 2 times δ1, it is determined that the temperature measuring device has an indication fault.

[0119] Furthermore, when the absolute values ​​of two temperature difference values ​​associated with the real-time temperature value of any channel are both greater than 2 times δ1, and the absolute value of the other temperature difference value is less than or equal to δ1, it is determined that the channel has an indication fault.

[0120] If the temperature measuring device is judged to have no indication fault in the first stage, further judgment shall be made according to the second stage, such as Figure 4 As shown, the second stage of self-diagnosis of the temperature measuring device includes:

[0121] (1) Based on the real-time temperature value T J(k) is the j value, and the ambient temperature T is read at the same time H (k) is the i value, through P J Normal operation indication value of the channel T J (i,j), reverse calculation of P J The calculated value of the measured temperature of the channel T JS (k);

[0122] Here, the calculation steps for the calculated value of the measured temperature of the oil tank channel include:

[0123] Known normal operating indication value T J (i,j) array, real-time temperature value T J (k) and ambient temperature T H (k) Calculate the measured temperature value according to the following method;

[0124] According to the ambient temperature T H (k) Determine the normal operating value T according to the following rules: J (i,j) The value of i in the array: i1<T H (k)=i≤i2;

[0125] According to the real-time temperature value T J (k) Determine the normal operating value T according to the following rules: J (i,j) The value of j in the array: j1<T J (k) = j ≤ j2;

[0126] From the normal operating value T J (i,j) value T in array J (i1,j1),T J (i1,j2),T J (i2,j1) and T J (i2,j2);

[0127] Calculate the measured temperature value T according to the following formula JS (k);

[0128]

[0129] (2) Based on the real-time temperature value T A (k) is the j value, and the ambient temperature T is read at the same time H (k) is the i value, through P A Channel normal operation indication value T A (i,j), reverse calculation of P A The calculated value of the measured temperature of the channel T AS (k);

[0130] (3) Based on the real-time temperature value T B(k) is the j value, and the ambient temperature T is read at the same time H (k) is the i value, through P B Channel normal operation indication value T B (i,j), reverse calculation of P B The calculated value of the measured temperature of the channel T BS (k);

[0131] (4) Further calculate the deviation increment between the temperature measurement channels:

[0132] ΔT JAS (k) = T JS (k)-T AS (k)

[0133] ΔT JBS (k) = T JS (k)-T BS (k)

[0134] ΔT ABS (k) = T AS (k)-T BS (k)

[0135] (5) When ΔT JAS When the absolute value of (k) is not greater than δ2, if the following equation holds, then P B The channel has a faulty indication; N P B The deviation increment of the channel, when N ΔT per day JAS (k) When the sum of the absolute values ​​is not greater than N times δ2, all real-time temperature values ​​within the range of k = 1 to N on that day are determined by the following formula. When any of the above formulas holds true, P is determined. B There is an indication fault in the channel:

[0136] |T B (k)-T JS (k)|>δ1+δ3

[0137] |T B (k)-T AS (k)|>δ1+δ4

[0138] (6) When ΔT JBS When the absolute value of (k) is not greater than δ3, if the following equation holds, then P A The channel has a faulty indication; N P A The deviation increment of the channel, when N ΔT per day JBS (k) When the sum of the absolute values ​​is not greater than N times δ3, then when all real-time temperature values ​​in the range of k = 1 to N on that day are determined by the following formula, when any of them is true, it is determined that P AThe presence indication fault of the channel:

[0139] |T A (k)-T JS (k)|>δ1+δ2

[0140] |T A (k)-T BS (k)|>δ1+δ4

[0141] (7) When ΔT ABS When the absolute value of (k) is not greater than δ4, if the following equation holds, then P J The channel has a faulty indication; N P J The deviation increment of the channel, when N ΔT per day ABS (k) When the sum of the absolute values ​​is not greater than N times δ4, then when all real-time temperature values ​​within the range of k = 1 to N on that day are determined by the following formula, when any of them is true, it is determined that P J There is an indication fault in the channel;

[0142] |T J (k)-T AS (k)|>δ1+δ2

[0143] |T J (k)-T BS (k)|>δ1+δ3

[0144] After considering the ambient temperature, the real-time temperature value of each temperature measurement channel is measured, and the known normal operating value T J (i, j) array, calculate the measured temperature calculated value of each fuel tank channel, and make further judgment on the deviation increment of the temperature of each fuel tank channel according to the measured temperature calculated value, so as to improve the accuracy and purpose of self-diagnosis, and make indication fault judgment for the temperature measurement structure of the fuel tank channel with specific fault.

[0145] When the second stage determines that the temperature measuring device has no indication fault, further determination is made according to the third stage, such as Figure 5 As shown, the third stage of the determination of the measuring device includes:

[0146] (1) Calculate ΔT according to the following formula JAX (k) and ΔT JBX (k) is assigned; P is calculated based on the assigned value J Channel deviation ΔT JX , when ΔT JX When it is greater than δ5, it is determined that P J There is a value indication fault in the channel;

[0147] ΔT JAX (k)=(TJ (k)-T AS (k)) / (δ1+δ2)

[0148] ΔT JBX (k)=(T J (k)-T BS (k)) / (δ1+δ3)

[0149]

[0150] (2) Calculate ΔT according to the following formula AJX (k) and ΔT ABX (k) is assigned; P is calculated based on the assigned value A Channel deviation ΔT AX , when ΔT JX When it is greater than δ5, it is determined that P A There is an indication fault in the channel;

[0151] ΔT AJX (k)=(T A (k)-T JS (k)) / (δ1+δ2)

[0152] ΔT ABX (k)=(T A (k)-T BS (k)) / (δ1+δ4)

[0153]

[0154] (3) Calculate ΔT according to the following formula JAX (k) and ΔT JBX (k) is assigned; P is calculated based on the assigned value B Channel deviation ΔT BX , when ΔT JX When it is greater than δ5, it is determined that P B There is a value indication fault in the channel;

[0155] ΔT BJX (k)=(T B (k)-T JS (k)) / (δ1+δ3)

[0156] ΔT BAX (k)=(T B (k)-T AS (k)) / (δ1+δ4)

[0157]

[0158] By considering the repeatability of each tank channel and combining it with the ambient temperature, the assignments between the corresponding tank channels are confirmed. Based on the assignments associated with the tank channels, the average value is taken after summing up the data from multiple measurements to obtain the operating deviation of the corresponding channel. This is compared with the proportional coefficient for determining the operating accuracy of the temperature measuring device to determine the operating accuracy of the corresponding tank channel. Based on the data from multiple measurements, the effectiveness of the third stage determination and the accuracy of the determination results are improved.

[0159] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A self-diagnosis method for the operating accuracy of a temperature measuring device of a substation, characterized in that: The temperature measuring device of the method diagnosis includes three groups of independent temperature measuring oil tank channels and an environmental channel for measuring the ambient temperature. The method includes the following steps: S1: Obtain the real-time temperature measured by each channel of the temperature measuring device, calculate the temperature difference between the temperatures measured by any two fuel tank channels, and compare the obtained temperature difference with the allowable error limit of the indication; S2: If the obtained differences all meet the requirements, execute S3; if there are differences that do not meet the requirements, the measuring device has an indication fault; S3: Combine the measured temperature of each fuel tank channel with the measured temperature of the environment channel, calculate the measured temperature calculation value corresponding to each fuel tank channel, obtain the deviation increment of the measured temperature calculation values ​​of any two fuel tank channels, and determine the indication of each fuel tank channel; S4: If any of the fuel tank channels does not meet the requirements, the measuring device has an indication fault; if all three groups of fuel tank channels meet the requirements, execute step S5; S5: Calculate the corresponding assigned value according to the measured temperature calculation value of each fuel tank channel, further determine the deviation of the related assigned value of the same fuel tank channel, and judge the indication of the corresponding fuel tank channel according to the deviation of each fuel tank channel; S6: If the assigned deviation of any fuel tank channel does not meet the requirements, the measuring device has an indication fault; if the assigned deviations of the three groups of fuel tank channels all meet the requirements, the operating accuracy of the measuring device meets the requirements.

2. A self-diagnosis method for the operation accuracy of a temperature measuring device for a substation according to claim 1, characterized in that: The real-time temperature value of the temperature measuring device obtained in S1 is judged, and if the condition is met, S2 is executed. The judgment of the real-time temperature value includes the following steps: S11: Obtain the change in the real-time temperature of the three groups of fuel tank channels, and determine whether the change in the temperature of each group of fuel tank channels is less than or equal to 0.1°C per ten minutes; if so, execute S13; otherwise, execute S12; S12: Determine whether the change amount of each group of fuel tank channels continuously increases or decreases at a rate less than or equal to 0.3°C per minute, and the duration is greater than 30 minutes; if so, execute S14, otherwise, execute S11; S13: Obtain the temperature differences between the three groups of fuel tank channels and determine whether each temperature difference is greater than 5°C; if so, execute S14; otherwise, execute S11; S14: Obtain the difference between the real-time temperature and the preset temperature value, and determine whether the difference is greater than or equal to 5°C; if so, the real-time temperature measured by this group meets the conditions; otherwise, execute S11.

3. A self-diagnosis method for the operation accuracy of a temperature measuring device for a substation according to claim 1, characterized in that: The temperature difference determination of the fuel tank passage in S2 includes the following steps: S21: Obtain the temperature difference between any two fuel tank channels. If any temperature difference is greater than twice the allowable error of the indication, the temperature measuring device has an indication fault, and S22 is executed; otherwise, S3 is executed; S22: If the two temperature differences associated with any tank channel are greater than twice the allowable error of indication, and the temperature differences of the other two tank channels are less than or equal to the allowable error of indication, then there is an indication fault in the tank channel.

4. A self-diagnosis method for the operation accuracy of a temperature measuring device for a substation according to claim 1, characterized in that: In S3, the specific steps of judging the indication of each fuel tank channel include: For the check tank channel, obtain the deviation increment of the measured temperature calculation values ​​of the other two tank channels, and calculate the absolute value of the difference between the measured temperature of the check tank channel and the measured temperature calculation values ​​of the other two tank channels; If the deviation increment of the calculated values ​​of the measured temperatures of the other two tank channels is less than or equal to the repeatability error limit of the calibration tank channel, and the absolute value of the difference between the measured temperature of the calibration tank channel and the calculated values ​​of the measured temperatures of the other two tank channels is greater than the sum of the allowable error of the indication and the repeatability error limit of the corresponding tank channel, then there is an indication fault in the calibration tank channel.

5. A self-diagnosis method for the operation accuracy of a temperature measuring device for a substation according to claim 1, characterized in that: In S3, the specific steps of obtaining the calculated values ​​of the measured temperatures of each group of fuel tank channels include: Obtaining the normal operation indication value T(i, j) array of the fuel tank channel, and the real-time temperature value and ambient temperature of the fuel tank channel obtained by the measuring device; Determine the value i from the array of normal operating indication values ​​T(i, j) according to the ambient temperature, and determine the value j from the array of normal operating indication values ​​T(i, j) according to the real-time temperature value of the fuel tank channel; According to the values ​​of i and j, take the values ​​T(i1, j1), T(i1, j2), T(i2, j1) and T(i2, j2) from the array of normal operation indication values ​​T(i, j), where i1<=i≤i2, j1<=j≤j2; The measured temperature value of the fuel tank channel is calculated based on the taken value.

6. A self-diagnosis method for the operation accuracy of a temperature measuring device for a substation according to claim 5, characterized in that: The expression of the calculated value of the measured temperature of the fuel tank channel is obtained as follows: In the formula, Among them, i1<T H (k)=i≤i2,j1<T J (k)=j≤j2,T J (k) represents the real-time temperature value of the channel, T H (k) represents the ambient temperature, T J (i1, j1), T J (i1, j2), T J (i2, j1) and T J (i2, j2) represents the known value selected from the normal operating value array T(i, j), T JS (k) represents the calculated value of the measured temperature of the tank channel.

7. A self-diagnosis method for the operation accuracy of a temperature measuring device for a substation according to claim 1, characterized in that: In S5, the specific steps of determining the fault of the temperature measuring device include: Calculating the assigned values ​​associated with the other two groups of fuel tank channels based on the real-time temperature value of the fuel tank channel and the measured temperature calculated values ​​associated with the other two groups of fuel tank channels; Calculate the deviation of the oil tank channel according to the assigned value, and compare the deviation with the proportional coefficient of the qualified judgment of the operation accuracy of the temperature measuring device; If the deviation of the fuel tank channel is greater than the proportional coefficient for determining the qualified operation accuracy, the corresponding fuel tank channel has an indication fault.

8. A self-diagnosis method for the operation accuracy of a temperature measuring device for a substation according to claim 7, characterized in that: The expression for assigning one group of fuel tank channels to the other two groups of fuel tank channels is: Where, T J (k) represents the real-time temperature value of the fuel tank channel to be diagnosed, T AS (k) and T BS (k) represents the calculated value of the measured temperature of the oil tank channel to be diagnosed and the other two groups of oil tank channels, δ1 represents the allowable error limit of the indication of the temperature measuring device, and δ2 and δ3 represent the repeatability error limits corresponding to the oil tank channel to be diagnosed and the other two groups of oil tank channels respectively.

9. A self-diagnosis method for the operation accuracy of a temperature measuring device for a substation according to claim 8, characterized in that: The specific steps of calculating the deviation of the fuel tank channel according to the assigned value include: Calculate the values ​​of the fuel tank channel to be diagnosed and the other two groups of fuel tank channels for multiple measurements, and then add them together; The sum of the values ​​assigned to the fuel tank channel to be diagnosed is divided by the number of the values ​​assigned, and the absolute value of the quotient is taken to obtain the deviation of the fuel tank channel to be diagnosed.

10. A self-diagnosis method for the operation accuracy of a temperature measuring device for a substation according to claim 9, characterized in that: The expression of the deviation of the fuel tank channel to be diagnosed is: In the formula, and It represents the sum of the values ​​assigned by multiple measurements of the fuel tank channel to be diagnosed and the other two groups of fuel tank channels, and N represents the number of measurements of the fuel tank channel to be diagnosed and a group of fuel tank channels, that is, the corresponding number of values ​​assigned.

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