CN111722656A - Transformer temperature control method and transformer - Google Patents
Transformer temperature control method and transformer Download PDFInfo
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- CN111722656A CN111722656A CN201910203875.4A CN201910203875A CN111722656A CN 111722656 A CN111722656 A CN 111722656A CN 201910203875 A CN201910203875 A CN 201910203875A CN 111722656 A CN111722656 A CN 111722656A
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K15/00—Testing or calibrating of thermometers
- G01K15/005—Calibration
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K3/00—Thermometers giving results other than momentary value of temperature
- G01K3/08—Thermometers giving results other than momentary value of temperature giving differences of values; giving differentiated values
- G01K3/14—Thermometers giving results other than momentary value of temperature giving differences of values; giving differentiated values in respect of space
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/08—Cooling; Ventilating
- H01F27/085—Cooling by ambient air
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/08—Cooling; Ventilating
- H01F27/10—Liquid cooling
- H01F27/12—Oil cooling
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/40—Structural association with built-in electric component, e.g. fuse
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/40—Structural association with built-in electric component, e.g. fuse
- H01F27/402—Association of measuring or protective means
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/40—Structural association with built-in electric component, e.g. fuse
- H01F27/402—Association of measuring or protective means
- H01F2027/404—Protective devices specially adapted for fluid filled transformers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/40—Structural association with built-in electric component, e.g. fuse
- H01F27/402—Association of measuring or protective means
- H01F2027/406—Temperature sensor or protection
Abstract
The invention discloses a transformer temperature control method, which comprises the following steps: detecting the temperature of top oil in an oil tank through a first temperature sensor in the transformer oil tank; calculating the heat dissipation Q of the contact part of the bottom surface of the transformer and the supporting part in unit time; calculating whether the absolute value of the difference value between the ground heat dissipation capacity and the oil surface temperature is greater than a temperature difference threshold value or not; collecting the three-phase pile head temperature of the m-time transformer; acquiring the oil surface temperature for n times; determining the heating quantity of the transformer; measuring the current equipment temperature of an oil pump of a transformer cooler group in operation; acquiring the calibration temperature of an oil surface temperature calibration sensor; judging whether the difference between the calibration temperature and the current equipment temperature of the oil pump of the cooler exceeds the standard or not; calculating the temperature of a transformer winding and the service life of the transformer; sending the predicted life value of the transformer to a cloud server; and the cloud server classifies the life cycle of the transformer according to the obtained predicted life value, and records the latest obtained life cycle classification in a cloud server memory.
Description
Technical Field
The invention relates to the field of transformers, in particular to a transformer temperature control method and a transformer.
Background
A power transformer is an important electrical device in a power system, and the operation condition of the power transformer affects the safety and reliability of the power system as a whole. The transformer fault caused by the insulation aging of the transformer due to the over-temperature operation of the winding occupies a large proportion of the faults of the power system, so the measurement of the transformer oil temperature has an extremely important significance for preventing the transformer fault. At present, the measurement of the oil temperature of the power transformer is mainly realized by a transformer thermometer and related devices matched with the transformer thermometer. In the long-term operation and use process, the accuracy of the thermometer is reduced along with the use duration, so that the detection result has errors and even errors, the effective monitoring on the temperature of the transformer is lost, and a series of potential threats are generated to a power system. Therefore, the maintenance personnel need to calibrate the thermometer accurately at regular intervals. The winding temperature is the basis for the safe operation of the transformer, so the winding temperature of the transformer must be monitored in real time during the operation of the transformer. The BWR-04 type winding temperature controller used in the present electric power system is a special instrument designed for oil immersed power transformer. The transformer winding temperature T1 is the sum of the transformer top layer oil temperature T2 and the winding temperature rise Δ T (i.e., T1 is T2+ Δ T), wherein the winding temperature rise Δ T is determined by the transformer winding current, and the current of the secondary side of the current transformer is directly proportional to the winding current; the working principle of the winding temperature controller is that the winding temperature of the transformer is indirectly measured by adopting a thermal simulation method, the working principle is that the current of the secondary side of the current transformer which is in direct proportion to the load is taken out through the current transformer, the current is adjusted by the current transformer and then is input into an electric heating element in an elastic element of the winding temperature controller, the elastic element generates an additional displacement by the heat generated by the electric heating element, so that a temperature indicated value which is higher than the oil temperature by a temperature difference delta T is generated, and the winding temperature controller obtains the average indicated value of the winding temperature by the indirect method. The digital display temperature controller is arranged in the control machine room, a transmitter in the winding temperature controller converts a temperature signal into a (4-20) mA current signal, and the mA current signal is input into the digital display temperature controller, so that an operator on duty can conveniently observe the temperature of the transformer winding in the control room, and simultaneously can output the following signals as the input of the computer monitoring system according to the needs of a user. A winding thermometer used for an oil-immersed transformer belongs to a pressure type temperature instrument, the oil temperature is measured through the pressure type thermometer, the winding current is measured through TA, current signals are mechanically superposed on the basis of the oil temperature through a radiator, and a meter indicates the winding temperature and outputs remote signals. The controller generally comprises controller, matcher, secondary instrument, and the expense is higher, but practical application is less, does not generally insert non-electric quantity control loop, moreover because the easy corrosion of mechanical part, the potentiometre in the controller is fragile more, and the meter structure is complicated, the price is expensive, the maintenance degree of difficulty is big, seriously influences on-the-spot meter instruction and monitored control system temperature display.
Disclosure of Invention
An object of the present invention is to provide a transformer temperature control method and a transformer, which can effectively control the temperature of the transformer according to the top temperature condition of the transformer.
Specifically, the invention is realized by the following technical scheme:
a method of transformer temperature control, the method comprising:
s1: detecting the temperature of top oil in an oil tank through a first temperature sensor in the transformer oil tank;
s2: if the average temperature of top layer oil in the oil tank detected in N1 seconds is greater than the preset upper limit temperature, the controller acquires the running accumulated time of all fans of the fan set, and puts the fan set with the longest accumulated stop time into cooling;
s3: calculating the heat dissipation Q of the contact part of the bottom surface of the transformer and the supporting part in unit time;
s4: calculating whether the absolute value of the difference value between the ground heat dissipation capacity and the oil surface temperature is larger than a temperature difference threshold value, if so, executing S5, and if not, executing S13;
s5: collecting the three-phase pile head temperature of the m-time transformer;
s6: acquiring the oil surface temperature for n times;
s7: calculating whether the absolute value of the sum of the pile head temperature and the oil surface temperature is smaller than the heat dissipation quantity Q of the contact part of the bottom surface of the transformer and the supporting part in unit time, if so, executing S8, and if not, executing S9;
s8: determining the heating quantity of the transformer;
s9: starting a working cooler group oil pump, wherein the maximum frequency of a frequency converter of the working cooler group oil pump is limited to fmax, the initial frequency of the frequency converter of the working cooler group oil pump is f1, and at the moment, the frequency converter of the working cooler group oil pump operates at the initial frequency of f1 and operates at a constant frequency and a constant speed;
s10: measuring the current equipment temperature of an oil pump of a transformer cooler group in operation;
s11: acquiring the calibration temperature of an oil surface temperature calibration sensor;
s12: judging whether the difference value between the calibration temperature and the current equipment temperature of the oil pump of the cooler exceeds the standard or not, if so, executing S16, otherwise, executing S13;
s13: calculating the temperature of a transformer winding and the service life of the transformer;
s14: judging whether the service life of the transformer exceeds a preset service life value, if so, giving an alarm, and if not, executing S16;
s15: determining the number of starting oil pumps according to the top oil temperature;
s16: collecting the address of the transformer;
s17: sending the predicted life value of the transformer to a cloud server;
s18: and the cloud server classifies the life cycle of the transformer according to the obtained predicted life value, and records the latest obtained life cycle classification in a cloud server memory.
Preferably, the S8 includes:
s81: calculating the cooling coefficient of the transformer;
s82: collecting the wind speed of a transformer cooling fan;
s83: determining the temperature of a transformer winding according to the load current of the high-voltage side of the transformer;
s84: calculating the heat dissipation temperature of the transformer according to the winding trimming temperature of the transformer;
s85: and determining the heating temperature of the transformer according to the heat dissipation capacity of the transformer.
Preferably, the S15 includes:
s151: detecting a top layer oil temperature, and starting n1 groups of oil pumps when the top layer oil temperature is in a temperature interval (T1 ', T1 ' + n1 delta T1), wherein T1 ' represents a first temperature threshold value, delta T1 represents a set first temperature rise value, and n1 represents a positive integer;
s152: every X seconds, respectively calculating the average value of all first top layer oil temperature values and all second top layer oil temperature values counted in the previous X seconds, and respectively recording the calculated average value of the first top layer oil temperature values and the calculated average value of the second top layer oil temperature values as a first calculated value and a second calculated value;
s153: starting the n2 groups of oil pumps when the mean value of the first and second calculated values is in a temperature interval (T1 ', T1 ' + n2 Δ T2), wherein T1 ' represents a first temperature threshold, Δ T2 represents a set second temperature rise and Δ T2< Δ T1, n2 represents a positive integer;
s154: and comparing the second calculated value with a preset maximum allowable oil temperature value, and outputting an oil temperature abnormal signal if the second calculated value exceeds the maximum allowable oil temperature value.
Preferably, in S3, assuming that the heat transfer coefficient of the material of the bottom surface of the transformer is B1, the heat transfer coefficient of the material of the supporting portion is B2, and the contact area between the bottom surface of the transformer and the supporting portion is S, the heat dissipation Q per unit time of the contact portion between the bottom surface of the transformer and the supporting portion is determined as:
wherein, Δ T represents the difference between the temperature of the transformer insulating oil and the current outdoor temperature.
Preferably, in S81, transformer power is calculatedThe ratio of the thermal temperature T' to the heat dissipation Q per unit time of the contact portion between the bottom surface and the support portion of the transformer is calculated
And
to obtain the cooling coefficient d of the transformer, i.e.
Preferably, in S84, the transformer heat dissipation temperature TPowder medicine＝T’/4πR2*(S + E) × W, wherein R is the vertical distance between the geometric center point of the winding of the transformer and the oil surface, T' is the temperature wrapped by a sphere which is obtained by measurement, takes the geometric center point of the winding of the transformer as the circle center and takes R as the radius, W is a preset heat dissipation coefficient related to the wind speed of the transformer heat dissipation fan, and the larger the wind speed of the transformer heat dissipation fan is, the smaller the wind speed of the transformer heat dissipation fan is, and the smaller W is.
Preferably, in S16, the address information of the transformer is configured and stored in the single chip, the address information of the transformer is the number of the transformer, each transformer has an individual number, each number corresponds to an actual road section address of the relevant transformer, the single chip sends the address information of the transformer to the cloud server for further processing through the GPRS module according to the determination requirement, the cloud server stores the number of each transformer, and then the actual position of the transformer corresponding to the number is known according to the address of each transformer in the address book, so as to inform the maintenance personnel of the maintenance before in time.
Preferably, in S17, the predicted life value of the transformer is uploaded to a cloud server through a communication module; the communication module exchanges data with the cloud server through a wireless data network; the control module is a single chip microcomputer controller; the control module also comprises a human-computer interaction terminal, and the human-computer interaction terminal comprises a parameter setting module and a structure analysis module; the parameter setting module generates a control signal according to a test parameter set by a user, transmits the control signal to a corresponding intelligent verification terminal through the cloud server, and changes a detection parameter of the intelligent verification terminal; the result analysis module is used for analyzing and calculating the related data obtained from the cloud server and sending the result of the analysis and calculation to the cloud server for storage; the human-computer interaction terminal also comprises a self-starting module, wherein the self-starting module prestores detection parameters and periodically sends a control signal to the intelligent verification terminal through the data cloud network; the human-computer interaction terminal also comprises a report printing module, and the report printing module prints and outputs the calculation result obtained by the result analysis module.
Preferably, in S18, the life cycle of the transformer is divided into a first stage to a third stage, and when the predicted life value is smaller than the life value c, the life cycle of the transformer is classified into a first class; when the predicted life value is in the interval from the life value c to the life value d, classifying the life cycle of the transformer into a second class; when the predicted life value is larger than the life value d, classifying the life cycle of the transformer into a third class; wherein the life value c is less than the life value d.
A transformer uses the aforementioned transformer temperature control method.
The invention has the beneficial effects that: the temperature of the transformer can be effectively and dynamically controlled according to the top temperature condition of the transformer.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic flow chart of a transformer temperature control method according to the present invention;
FIG. 2 is a diagram illustrating the specific step of S8 in FIG. 1;
fig. 3 is a schematic diagram illustrating a specific step of S15 in fig. 1.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present invention. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.
The present invention will be described in detail below by way of examples.
A method of transformer temperature control, the method comprising:
s1: the temperature of top oil in the oil tank is detected through a first temperature sensor in the transformer oil tank.
An air cylinder is arranged in the inner wall of the transformer oil tank, the first temperature sensor horizontally moves back and forth on the top oil level of the oil tank under the driving of the air cylinder, and the time for the piston rod of the air cylinder to stretch out and draw back once is N1 seconds; the first temperature sensor outputs a first detected temperature value every second.
In another embodiment of the present invention, two first temperature sensors detect the top layer oil temperature and are driven by the cylinder to move, that is, the two first temperature sensors are fixed on the piston rod of the cylinder, and the distance between the two first temperature sensors is 60mm, so that the two first temperature sensors can be conveniently installed, and the two first temperature sensors can keep a proper distance to simultaneously detect different positions of the top layer oil.
S2: and if the average temperature of the top layer oil in the oil tank detected in N1 seconds is greater than the preset upper limit temperature, the controller acquires the running accumulated time of all fans of the fan set, and the fan set with the longest accumulated stop time is thrown into for cooling.
Adding the fan set with the longest accumulated stop time, delaying for a certain time, checking whether the fan fails, and adding the fan set with longer accumulated stop time when the fan fails; and when the oil temperature of the top layer of the transformer is lower than the oil temperature lower limit, cutting off the fan set with the longest accumulated operation time, delaying for a certain time, if the oil temperature of the top layer of the transformer is still lower than the oil temperature lower limit, continuously cutting off the next group of air cooling devices with the longest accumulated operation time, and sequentially cutting off the last group of air cooling devices. The input of the fan is automatically controlled according to the temperature of the upper oil of the transformer, and the energy-saving operation of the fan is realized.
S3: and calculating the heat dissipation quantity Q of the contact part of the bottom surface of the transformer and the supporting part in unit time.
The insulating oil in the voltage transformer has large demand and high index requirement, and the hot oil circulation temperature of the insulating oil must reach 65 +/-5 ℃ so that the insulating oil can be normally installed; however, since the transformer is usually installed outdoors, especially in winter, the outdoor temperature is very low, especially in winter in the alpine region, the outdoor environment temperature is usually below-20 ℃, so that the temperature difference between the outdoor environment temperature in winter in the alpine region and the hot oil circulation temperature of the insulating oil is above 80 ℃, and the heat loss of the insulating oil is serious, thereby affecting the installation and subsequent operation stability of the transformer, and the insulating oil is inflammable, so that unsafe accidents are particularly easy to occur if fire prevention is not emphasized.
When the transformer is installed, the transformer is usually installed in a vertically and stably placed mode, namely, the transformer is installed in contact with the ground or other supporting parts, the bottom surface of the transformer and the supporting parts must have a large enough contact area to ensure the stable installation of the transformer, and therefore, the heat dissipation of the bottom surface of the transformer is increased.
And if the heat transfer coefficient of the material of the bottom surface of the transformer is B1, the heat transfer coefficient of the material of the supporting part is B2, and the contact area of the bottom surface of the transformer and the supporting part is S, determining the heat dissipation capacity Q of the contact part of the bottom surface of the transformer and the supporting part in unit time as follows:
wherein, Δ T represents the difference between the temperature of the transformer insulating oil and the current outdoor temperature.
S4: and calculating whether the absolute value of the difference value between the ground heat dissipation capacity and the oil surface temperature is larger than a temperature difference threshold value, if so, executing S5, and if not, executing S13.
If the judgment result is yes, the transformer is in a situation of always cooling under the current situation, and in the situation, the cooling situation of the transformer needs to be monitored and processed, so that the temperature of the transformer does not drop too low all the time; if the judgment result is no, the transformer is still in a temperature rising state under the current condition, and related monitoring and processing of temperature reduction are required.
S5: and collecting the three-phase pile head temperature of the transformer for m times.
The transformer is provided with a shell, and a low-voltage side three-phase pile head and a zero-phase pile head which are arranged in the shell, wherein the low-voltage side three-phase pile head comprises an A-phase pile head, a B-phase pile head and a C-phase pile head, voltages among the A-phase pile head, the B-phase pile head, the C-phase pile head and the zero-phase pile head 13 are all 220V, and under a normal condition, the low-voltage side three-phase pile head 12 is in an overheat state when the temperature reaches more than 60 ℃, and is in an abnormal state when the temperature reaches more than 70 ℃.
S6: and acquiring the oil surface temperature for n times.
The transformer is provided with an oil surface thermometer, the oil surface thermometer comprises a temperature sensor, the temperature sensor of the oil surface thermometer is immersed in an oil storage tank of the transformer, a control module is in signal connection with the temperature sensor of the oil surface thermometer, and the control module is in signal connection with the communication module; the control module sends out control signal and makes the temperature sensor of oil level thermometer gather the oil temperature data in the oil storage tank, and the temperature sensor of this oil level thermometer carries out temperature acquisition with preset data acquisition interval to obtain the multiunit oil level temperature of predetermineeing the duration.
S7: and (4) calculating whether the absolute value of the sum of the pile head temperature and the oil surface temperature is less than the heat dissipation quantity Q of the contact part of the bottom surface of the transformer and the supporting part in unit time, if so, executing S8, and if not, executing S13.
If the judgment result is yes, the danger of temperature reduction of the transformer exists indeed, measures need to be taken to control temperature increase, if the judgment result is no, the temperature of the transformer cannot be reduced too low in the current state, and the operation mainly based on temperature reduction is continued.
S8: the heating amount of the transformer is determined.
S9: and starting the working cooler group oil pump, wherein the maximum frequency of a frequency converter of the working cooler group oil pump is limited to fmax, the initial frequency of the frequency converter of the working cooler group oil pump is f1, and at the moment, the frequency converter of the working cooler group oil pump operates at the initial frequency of f1 and operates at a constant frequency and a constant speed.
S10: and measuring the current equipment temperature of the oil pump of the running transformer cooler group.
Specifically, an oil pump temperature sensor is arranged on the cooler oil pump and used for collecting the current equipment temperature of the cooler oil pump.
In this embodiment, the current device temperature of the oil pump of the cooler group includes an oil inlet pipe outer wall temperature T0, an oil return pipe outer wall temperature T1, and a cooling oil tank temperature Ta. This embodiment sets up temperature sensor through advancing oil pipe outer wall, returning oil pipe outer wall and cooling tank and gathers the temperature of relevant position in real time to give controlling means with the temperature value passback.
S11: and acquiring the calibration temperature of the oil surface temperature calibration sensor.
The transformer is also provided with an oil surface temperature calibration sensor, the control module is also in signal connection with the oil surface temperature calibration sensor, and the detection precision of the oil surface temperature calibration sensor is higher than that of the oil surface thermometer, so that the oil surface temperature information acquired by the oil surface temperature calibration sensor is more accurate, and the measurement error of the corresponding oil surface thermometer can be calculated and obtained. The accuracy verification of the transformer oil surface thermometer can be realized under the condition of no power failure.
S12: and judging whether the difference value between the calibration temperature and the current equipment temperature of the oil pump of the cooler group exceeds the standard or not, if so, executing S16, and otherwise, executing S13.
If the difference between the calibration temperature and the current equipment temperature of the oil pump of the cooler group exceeds the standard, the current equipment temperature is really higher, and the working performance of the transformer needs to be further detected so as to avoid the transformer from being out of order.
S13: and calculating the temperature of the transformer winding and the service life of the transformer.
S14: and judging whether the service life of the transformer exceeds a preset service life value, if so, giving an alarm, and if not, executing S16.
Specifically, the service life of the transformer is predicted according to the comparison between the winding temperature of the transformer and a numerical value in a preset temperature-service life curve.
If the service life of the transformer exceeds the preset service life value, the transformer is indicated to be in failure quickly, and alarm processing is needed.
S15: and determining the number of the starting oil pumps according to the top oil temperature.
S16: and collecting the address of the transformer.
The method comprises the steps that address information of transformers is configured in a single chip microcomputer to be stored, in order to simplify configuration information, the address information of the transformers can adopt the serial numbers of the transformers, each transformer is provided with an independent serial number, each serial number corresponds to the actual road section address of the relevant transformer, the address book of a power department recorded by the actual road section address of the transformers is sent to a cloud server through a GPRS module to be processed in real time according to the judgment requirement, the serial numbers of the transformers are stored in the cloud server, the actual positions of the transformers corresponding to the serial numbers can be obtained according to the addresses of the transformers in the address book, and a maintainer is informed to overhaul in time.
S17: and sending the predicted life value of the transformer to a cloud server.
Uploading the predicted life value of the transformer to a cloud server through a communication module; the communication module exchanges data with the cloud server through a wireless data network. The control module is a single chip microcomputer controller. The control module also comprises a human-computer interaction terminal, and the human-computer interaction terminal comprises a parameter setting module and a structure analysis module; the parameter setting module generates a control signal according to a test parameter set by a user, transmits the control signal to a corresponding intelligent verification terminal through the cloud server, and changes a detection parameter of the intelligent verification terminal; the result analysis module is used for analyzing and calculating the related data obtained from the cloud server and sending the result of the analysis and calculation to the cloud server for storage.
The man-machine interaction terminal also comprises a self-starting module, wherein the self-starting module prestores detection parameters and periodically sends control signals to the intelligent verification terminal through the data cloud network.
The human-computer interaction terminal also comprises a report printing module, and the report printing module prints and outputs the calculation result obtained by the result analysis module.
S18: and the cloud server classifies the life cycle of the transformer according to the obtained predicted life value, and records the latest obtained life cycle classification in a cloud server memory.
Specifically, the life cycle of the transformer may be classified into a plurality of levels, for example, in the embodiment of the present invention, the life cycle of the transformer is classified into a first level to a third level, and correspondingly, when the predicted life value is smaller than the life value c, the life cycle of the transformer is classified into a first class; when the predicted life value is in the interval from the life value c to the life value d, classifying the life cycle of the transformer into a second class; when the predicted life value is larger than the life value d, classifying the life cycle of the transformer into a third class; wherein the life value c is less than the life value d.
Specifically, the S8 includes:
s81: and calculating the cooling coefficient of the transformer.
The cooling coefficient refers to the cooling strength of the transformer, and is small, so that the heat dissipation is fast, the cooling coefficient is large, and the heat dissipation is slow. Specifically, the ratio of the heat dissipation temperature T' of the transformer to the heat dissipation quantity Q of the contact part of the bottom surface of the transformer and the supporting part in unit time is calculated, and then the ratio is calculated
And
to obtain the cooling coefficient d of the transformer, i.e.
S82: and collecting the wind speed of a cooling fan of the transformer.
The transformer radiator fan includes air inlet fan and air outlet fan, and an input of air inlet fan and air outlet fan all connects on the normally open end of the relay of transformer, another input of air inlet fan and air outlet fan all connects on zero looks pile head, and arbitrary looks pile head in the low pressure side three-phase pile head links to each other with the public end of relay, temperature sensor's temperature signal is gathered to the singlechip and according to this temperature signal output high level or low level to the relay drive circuit control relay normally open end and public end switch on or break off. The fan rotation centers of the air inlet fan and the air outlet fan are overlapped. The transformer is characterized in that the outer wall of the shell of the transformer is provided with an outer cover which is respectively covered outside the air inlet fan and the air outlet fan, and the outer cover is provided with a plurality of air vents. The ventilation holes are long-strip-shaped, and the upper edge of each ventilation hole extends to the lower side in a slanting direction to form a blocking piece.
S83: and determining the temperature of the transformer winding according to the load current of the high-voltage side of the transformer.
Specifically, a rated current corresponding to each gear of the transformer is collected, and linear proportionality coefficients a and b are obtained by fitting a linear equation shown in the following formula according to the rated current corresponding to each gear;
Ie＝aD+b
in the above formula, Ie represents rated current, D represents gear, D takes the value of 1, 2, 3, and a and b represent linear proportionality coefficients respectively;
calculating the winding temperature T of the transformer according to the formula;
T＝t+A(I/(aD+b))C
in the above formula, T represents the winding temperature of the transformer, T represents the top oil temperature of the transformer, I represents the high-voltage side load current of the transformer, D represents the current operating gear of the transformer, a and b represent linear proportionality coefficients, respectively, and a and C represent the aforementioned winding temperature calculation constants, respectively.
S84: and calculating the heat dissipation temperature of the transformer according to the winding trimming temperature of the transformer.
The transformer provided by the invention uses the radiator to control the temperature of the transformer, and the radiating temperature of the radiator and the winding correction temperature of the transformer need to meet a certain relation.
Radiating temperature T of transformerPowder medicine＝T’/4πR2*(S + E) × W, where R is the perpendicular distance of the geometric centre point of the windings of the transformer from the oil surface. The temperature wrapped by a sphere formed by taking the geometric center point of the winding of the transformer as the center of a circle and R as the radius is T ', namely the temperature of the unit area of the T ' diffused to the oil surface is T '/4 pi R2And (S + E) is the total area of the transformer shell, namely the temperature dissipated in unit area on the transformer shell is the temperature diffused to the oil surface by T', so that the heat dissipation can be ensured to be more sufficient. W is a heat dissipation coefficient related to the wind speed of the transformer heat dissipation fan, the larger the wind speed of the transformer heat dissipation fan is, the larger W is, and the smaller the wind speed of the transformer heat dissipation fan is, the smaller W is.
S85: and determining the heating temperature of the transformer according to the heat dissipation capacity of the transformer.
Specifically, the transformer is also internally provided with a heating device, the heating device determines the heating temperature of the heating device according to the heat dissipation temperature of the transformer, and the heating temperature is preferably 1.2 times of the heat dissipation temperature.
In the temperature control of transformer, often heat and the heat dissipation go on simultaneously, just can guarantee the dynamic balance of transformer temperature, lean on the reduction heat dissipation of taste, if incessantly carry out on-off operation to the fan, itself will cause the damage to the electric fan, perhaps incessantly carry out the start-stop operation to the oil pump, also can make the oil pump motor reduce in quick start-stop life-span, so should synthesize application heating and heat dissipation measure, just can guarantee with transformer temperature control in suitable temperature range.
Specifically, the S15 includes:
s151: detecting top layer oil temperature, and starting n1 groups of oil pumps when the top layer oil temperature is in a temperature interval (T1 ', T1 ' + n1 delta T1), wherein T1 ' represents a first temperature threshold value, delta T1 represents a set first temperature rising value, and n1 represents a positive integer.
S152: every X seconds, calculating the average value of all first top layer oil temperature values and all second top layer oil temperature values counted in the previous X seconds respectively, and recording the calculated average value of the first top layer oil temperature values and the calculated average value of the second top layer oil temperature values as a first calculated value and a second calculated value respectively.
S153: when the mean value of the first and second calculated values is in the temperature interval (T1 ', T1 ' + n2 Δ T2), n2 sets of oil pumps are started, wherein T1 ' represents a first temperature threshold, Δ T2 represents a set second temperature rise and Δ T2< Δ T1, n2 represents a positive integer.
S154: and comparing the second calculated value with a preset maximum allowable oil temperature value, and outputting an oil temperature abnormal signal if the second calculated value exceeds the maximum allowable oil temperature value.
The invention also provides a transformer using any one of the transformer temperature control methods.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A method of transformer temperature control, the method comprising:
s1: detecting the temperature of top oil in an oil tank through a first temperature sensor in the transformer oil tank;
s2: if the average temperature of top layer oil in the oil tank detected in N1 seconds is greater than the preset upper limit temperature, the controller acquires the running accumulated time of all fans of the fan set, and puts the fan set with the longest accumulated stop time into cooling;
s3: calculating the heat dissipation Q of the contact part of the bottom surface of the transformer and the supporting part in unit time;
s4: calculating whether the absolute value of the difference value between the ground heat dissipation capacity and the oil surface temperature is larger than a temperature difference threshold value, if so, executing S5, and if not, executing S13;
s5: collecting the three-phase pile head temperature of the m-time transformer;
s6: acquiring the oil surface temperature for n times;
s7: calculating whether the absolute value of the sum of the pile head temperature and the oil surface temperature is smaller than the heat dissipation quantity Q of the contact part of the bottom surface of the transformer and the supporting part in unit time, if so, executing S8, and if not, executing S9;
s8: determining the heating quantity of the transformer;
s9: starting a working cooler group oil pump, wherein the maximum frequency of a frequency converter of the working cooler group oil pump is limited to fmax, the initial frequency of the frequency converter of the working cooler group oil pump is f1, and at the moment, the frequency converter of the working cooler group oil pump operates at the initial frequency of f1 and operates at a constant frequency and a constant speed;
s10: measuring the current equipment temperature of an oil pump of a transformer cooler group in operation;
s11: acquiring the calibration temperature of an oil surface temperature calibration sensor;
s12: judging whether the difference value between the calibration temperature and the current equipment temperature of the oil pump of the cooler exceeds the standard or not, if so, executing S16, otherwise, executing S13;
s13: calculating the temperature of a transformer winding and the service life of the transformer;
s14: judging whether the service life of the transformer exceeds a preset service life value, if so, giving an alarm, and if not, executing S16;
s15: determining the number of starting oil pumps according to the top oil temperature;
s16: collecting the address of the transformer;
s17: sending the predicted life value of the transformer to a cloud server;
s18: and the cloud server classifies the life cycle of the transformer according to the obtained predicted life value, and records the latest obtained life cycle classification in a cloud server memory.
2. The transformer temperature control method according to claim 1, wherein the S8 includes:
s81: calculating the cooling coefficient of the transformer;
s82: collecting the wind speed of a transformer cooling fan;
s83: determining the temperature of a transformer winding according to the load current of the high-voltage side of the transformer;
s84: calculating the heat dissipation temperature of the transformer according to the winding trimming temperature of the transformer;
s85: and determining the heating temperature of the transformer according to the heat dissipation capacity of the transformer.
3. The transformer temperature control method according to claim 1, wherein the S15 includes:
s151: detecting a top layer oil temperature, and starting n1 groups of oil pumps when the top layer oil temperature is in a temperature interval (T1 ', T1 ' + n1 delta T1), wherein T1 ' represents a first temperature threshold value, delta T1 represents a set first temperature rise value, and n1 represents a positive integer;
s152: every X seconds, respectively calculating the average value of all first top layer oil temperature values and all second top layer oil temperature values counted in the previous X seconds, and respectively recording the calculated average value of the first top layer oil temperature values and the calculated average value of the second top layer oil temperature values as a first calculated value and a second calculated value;
s153: starting the n2 groups of oil pumps when the mean value of the first and second calculated values is in a temperature interval (T1 ', T1 ' + n2 Δ T2), wherein T1 ' represents a first temperature threshold, Δ T2 represents a set second temperature rise and Δ T2< Δ T1, n2 represents a positive integer;
s154: and comparing the second calculated value with a preset maximum allowable oil temperature value, and outputting an oil temperature abnormal signal if the second calculated value exceeds the maximum allowable oil temperature value.
4. The method of claim 1, wherein in step S3, when the heat transfer coefficient of the bottom material of the transformer is B1, the heat transfer coefficient of the material of the supporting portion is B2, and the contact area of the bottom surface of the transformer and the supporting portion is S, the heat dissipation Q per unit time of the contact portion of the bottom surface of the transformer and the supporting portion is determined as follows:
wherein, Δ T represents the difference between the temperature of the transformer insulating oil and the current outdoor temperature.
5. The method of claim 2, wherein in step S81, the ratio of the transformer heat dissipation temperature T' to the heat dissipation quantity Q per unit time of the contact part of the bottom surface and the supporting part of the transformer is calculated, and then the calculation is performed
And
to obtain the cooling coefficient d of the transformer, i.e.
6. The transformer temperature control method of claim 2, wherein in S84, the transformer heat dissipation temperature T isPowder medicine＝T’/4πR2*(S + E) × W, where R is in the winding geometry of the transformerThe vertical distance between the center point and the oil surface, T' is the temperature wrapped by a sphere which is obtained by measurement, takes the geometric center point of a winding of the transformer as the center of a circle and takes R as the radius, wherein W is a preset heat dissipation coefficient related to the wind speed of a transformer heat dissipation fan, the larger the wind speed of the transformer heat dissipation fan is, the larger W is, the smaller the wind speed of the transformer heat dissipation fan is, and the smaller W is.
7. The transformer temperature control method according to claim 1, wherein in S16, the address information of the transformer is stored in a single chip, the address information of the transformer is stored as a number of the transformer, each transformer has a separate number, each number corresponds to an actual road address of the relevant transformer, and on an address book of a power department recorded by the actual road address of the transformer, the single chip sends the address information of the transformer to a cloud server for further processing through a GPRS module according to the judgment requirement, the cloud server stores the number of each transformer, and then knows an actual position of the transformer corresponding to the number according to the address of each transformer in the address book, and notifies an inspector of the inspection before.
8. The transformer temperature control method according to claim 1, wherein in the S17, the predicted life value of the transformer is uploaded to a cloud server through a communication module; the communication module exchanges data with the cloud server through a wireless data network; the control module is a single chip microcomputer controller; the control module also comprises a human-computer interaction terminal, and the human-computer interaction terminal comprises a parameter setting module and a structure analysis module; the parameter setting module generates a control signal according to a test parameter set by a user, transmits the control signal to a corresponding intelligent verification terminal through the cloud server, and changes a detection parameter of the intelligent verification terminal; the result analysis module is used for analyzing and calculating the related data obtained from the cloud server and sending the result of the analysis and calculation to the cloud server for storage; the human-computer interaction terminal also comprises a self-starting module, wherein the self-starting module prestores detection parameters and periodically sends a control signal to the intelligent verification terminal through the data cloud network; the human-computer interaction terminal also comprises a report printing module, and the report printing module prints and outputs the calculation result obtained by the result analysis module.
9. The method according to claim 1, wherein in S18, the life cycle of the transformer is divided into a first stage to a third stage, and when the predicted life value is less than the life value c, the life cycle of the transformer is classified into a first class; when the predicted life value is in the interval from the life value c to the life value d, classifying the life cycle of the transformer into a second class; when the predicted life value is larger than the life value d, classifying the life cycle of the transformer into a third class; wherein the life value c is less than the life value d.
10. A transformer using the transformer temperature control method according to any one of claims 1 to 9.
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