CN116432406A - Method and device for calculating hot spot temperature of working winding of oil immersed transformer - Google Patents
Method and device for calculating hot spot temperature of working winding of oil immersed transformer Download PDFInfo
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Abstract
The invention relates to the technical field of transformers, in particular to a method and a device for calculating the hot spot temperature of a working winding of an oil immersed transformer, wherein the method comprises the following steps: acquiring historical work load data and historical work temperature data of a transformer, and analyzing and obtaining historical winding hot spot temperature data of the transformer; collecting real-time work load data and real-time work temperature data of the transformer; establishing a transformer winding hot spot temperature calculation model, and analyzing to obtain real-time winding hot spot temperature data of the transformer based on the transformer winding hot spot temperature calculation model; and analyzing to obtain the hot spot temperature data of the working winding of the transformer. According to the method, historical working data are collected, real-time working data are collected at the same time, top-layer oil temperature data and bottom-layer oil temperature data are calculated respectively through building a transformer winding hot spot temperature calculation model, real-time winding hot spot temperature data are obtained, comparison verification is conducted with the historical winding hot spot temperature data, and accuracy of oil immersed transformer working winding hot spot temperature calculation is improved.
Description
Technical Field
The invention relates to the technical field of transformers, in particular to a method and a device for calculating the hot spot temperature of a working winding of an oil immersed transformer.
Background
At present, with the rapid development of science and technology in China, the electricity consumption is greatly increased, the large-scale development of a digital power grid is also indispensable for adapting to electricity consumption conditions, with the development of the digital power grid, the informatization, the automation and the intellectualization are basically realized in the aspects of power generation and power transmission in China, but a large development space still exists in the aspects of power distribution and power consumption, wherein the improvement of a transformer for power distribution is of great importance.
For an oil immersed transformer, the internal heat generation mechanism and the internal heat transfer process of the oil immersed transformer are known, the internal temperature distribution of the transformer is not uniform, and the oil temperature in the transformer is particularly obvious when the transformer is in overload operation, the oil temperature in the transformer is possibly in a safe range, but the temperature of a winding hot spot exceeds a rated limit value, and when the temperature of the winding hot spot exceeds a reference temperature, the normal operation of the transformer is damaged. Therefore, in order to carry out reasonable dynamic load on the transformer, it is important to improve the calculation accuracy of the hot spot temperature of the transformer winding.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, provides a method and a device for calculating the hot spot temperature of an oil immersed transformer working winding, collects historical working data, collects real-time working data at the same time, calculates top-layer oil temperature data and bottom-layer oil temperature data respectively by establishing a transformer winding hot spot temperature calculation model to obtain real-time winding hot spot temperature data, compares and verifies the real-time winding hot spot temperature data with the historical winding hot spot temperature data, improves the efficiency of calculating the hot spot temperature of the oil immersed transformer working winding, and has extremely high application value.
The invention provides a method for calculating the hot spot temperature of a working winding of an oil immersed transformer, which comprises the following steps:
acquiring historical work load data and historical work temperature data of a transformer, and analyzing and obtaining historical winding hot spot temperature data of the transformer according to the historical work load data and the historical work temperature data;
collecting real-time work load data and real-time work temperature data of the transformer;
establishing a transformer winding hot spot temperature calculation model, and analyzing the real-time work load data and the real-time work temperature data based on the transformer winding hot spot temperature calculation model to obtain real-time winding hot spot temperature data of the transformer;
and analyzing and obtaining working winding hot spot temperature data of the transformer based on the historical winding hot spot temperature data and the real-time winding hot spot temperature data.
Further, the obtaining the historical workload data and the historical operating temperature data of the transformer includes:
and extracting the historical work load data and the historical work temperature data of the transformer from the historical work data of the transformer.
Further, the analyzing the historical winding hot spot temperature data of the transformer according to the historical workload data and the historical working temperature data includes:
analyzing and obtaining linear correlation coefficients of the historical workload data and the historical working temperature data based on the historical workload data and the historical working temperature data;
obtaining correction coefficients of the historical workload data and the historical working temperature data based on sample data analysis of abrupt changes between the historical workload data and the historical working temperature data;
analyzing and obtaining historical working temperature change data of the transformer based on the linear correlation coefficient and the correction coefficient;
and extracting historical winding hot spot temperature data of the transformer from the historical operating temperature change data.
Further, the collecting real-time workload data and real-time operating temperature data of the transformer includes:
real-time working load data of the transformer are obtained based on a voltage sensor arranged on the transformer, and real-time working temperature data of the transformer are obtained based on a fiber bragg grating sensor arranged on the transformer.
Further, the real-time working temperature data comprises real-time hot spot position temperature data, real-time top layer oil temperature data and real-time bottom layer oil temperature data.
Further, the establishing a transformer winding hot spot temperature calculation model, analyzing the real-time work load data and the real-time work temperature data based on the transformer winding hot spot temperature calculation model, and the obtaining the real-time winding hot spot temperature data of the transformer includes:
establishing a top-layer oil temperature heat path calculation model;
obtaining a correction coefficient of the top-layer oil temperature heat circuit calculation model based on nonlinear thermal resistance data analysis of the transformer;
correcting the top-layer oil temperature heat circuit calculation model based on the correction coefficient to obtain a top-layer oil temperature heat circuit calculation improved model;
and analyzing the real-time work load data and the real-time work temperature data based on the top-layer oil temperature heat circuit calculation improved model to obtain real-time winding hot spot temperature data of the transformer.
Further, the calculation formula of the top-layer oil-temperature heat circuit calculation improved model comprises:
wherein K is a load factor, P 1′ For corrected load loss, θ 1 Is the top layer oil temperature, theta 2 Mu, temperature of hot spot position 1 In order to change the viscosity of the oil,
for rated hot spot temperature to top oil temperature rise, a is empirical index, ρ θ Is the oil density coefficient, τ 2 Is the transformer winding time constant.
Further, the establishing a transformer winding hot spot temperature calculation model, analyzing the real-time work load data and the real-time work temperature data based on the transformer winding hot spot temperature calculation model, and obtaining the real-time winding hot spot temperature data of the transformer further includes:
establishing a bottom oil temperature heat path calculation model;
and analyzing the real-time work load data and the real-time work temperature data based on the bottom oil temperature heat circuit calculation model to obtain real-time winding hot spot temperature data of the transformer.
Further, the calculation formula of the bottom oil temperature heat circuit calculation model includes:
wherein K is a load factor, P 1′ For corrected load loss, θ 3 Is the bottom oil temperature, theta 2 The temperature of the hot spot position is a empirical index, and C is the total heat capacity of the transformer.
The invention also provides a device for calculating the hot spot temperature of the winding of the oil-immersed transformer, which comprises:
the historical data analysis module is used for acquiring historical work load data and historical work temperature data of the transformer and analyzing and obtaining historical winding hot spot temperature data of the transformer according to the historical work load data and the historical work temperature data;
the real-time data collection module is used for collecting real-time work load data and real-time work temperature data of the transformer;
the real-time data analysis module is used for establishing a transformer winding hot spot temperature calculation model, analyzing the real-time work load data and the real-time work temperature data based on the transformer winding hot spot temperature calculation model, and obtaining real-time winding hot spot temperature data of the transformer;
and the data comprehensive analysis module is used for analyzing and obtaining working winding hot spot temperature data of the transformer based on the historical winding hot spot temperature data and the real-time winding hot spot temperature data.
According to the method, the historical workload data and the historical working temperature data of the transformer are collected, the historical winding hot spot temperature data of the transformer is obtained through analysis by calculating the linear correlation coefficient and the correction coefficient of the historical workload data and the historical working temperature data, the influence of suddenly changed sample data on a calculation result is fully considered, the calculation precision is improved, and a reference is provided for calculating the winding hot spot temperature data; the real-time work load data and the real-time work temperature data of the transformer are obtained based on the voltage sensor and the fiber bragg grating sensor, so that the collected data are more accurate; respectively establishing a top-layer oil temperature heat circuit calculation model and a bottom-layer oil temperature heat circuit calculation model, synthesizing calculation results of the two models to obtain real-time winding hot spot temperature data of the transformer, and improving calculation accuracy of the real-time winding hot spot temperature data; and comparing and verifying the real-time winding hot spot temperature data with the historical winding hot spot temperature data, so that the efficiency and the accuracy of the calculation of the working winding hot spot temperature of the oil-immersed transformer are improved, and the method has higher application value.
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In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings which are required in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flowchart of calculating a hot spot temperature of a working winding of an oil-immersed transformer according to a first embodiment of the present invention;
FIG. 2 is a flow chart of the analysis of historical winding hot spot temperature data of a transformer according to the historical workload data and the historical operating temperature data in a first embodiment of the invention;
FIG. 3 is a flowchart of obtaining real-time winding hot spot temperature data of a transformer based on a top-layer oil temperature heat circuit calculation model according to a first embodiment of the present invention;
FIG. 4 is a flowchart of obtaining real-time winding hot spot temperature data of a transformer based on a bottom oil temperature heat circuit calculation model according to a first embodiment of the present invention;
fig. 5 is a schematic diagram of a hot spot temperature calculating device for an oil immersed transformer in a second embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the present invention, it should be understood that terms such as "comprises" or "comprising," etc., are intended to indicate the presence of features, numbers, steps, acts, components, portions, or combinations thereof disclosed in the present specification, and are not intended to exclude the possibility that one or more other features, numbers, steps, acts, components, portions, or combinations thereof are present or added.
In addition, it should be noted that, without conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.
Example 1
The embodiment of the invention relates to a method for calculating the hot spot temperature of a working winding of an oil immersed transformer, which comprises the following steps: acquiring historical work load data and historical work temperature data of a transformer, and analyzing and obtaining historical winding hot spot temperature data of the transformer according to the historical work load data and the historical work temperature data; collecting real-time work load data and real-time work temperature data of the transformer; establishing a transformer winding hot spot temperature calculation model, and analyzing the real-time work load data and the real-time work temperature data based on the transformer winding hot spot temperature calculation model to obtain real-time winding hot spot temperature data of the transformer; and analyzing and obtaining working winding hot spot temperature data of the transformer based on the historical winding hot spot temperature data and the real-time winding hot spot temperature data.
In an alternative implementation manner of the present embodiment, as shown in fig. 1, fig. 1 shows a flowchart of calculating a hot spot temperature of a working winding of an oil-immersed transformer in a first embodiment of the present invention, including the following steps:
s101, acquiring historical work load data and historical work temperature data of a transformer, and analyzing and obtaining historical winding hot spot temperature data of the transformer according to the historical work load data and the historical work temperature data;
in an alternative implementation of the present embodiment, the historical workload data and the historical operating temperature data of the transformer are extracted from the historical operating data of the transformer.
Specifically, historical work load data and historical work temperature data of the transformer among five years are extracted from the historical work data of the transformer, the historical work load data and the historical work temperature data are divided into a plurality of historical time-division work load data and historical time-division work temperature data according to preset time intervals, the relation between the data of corresponding time periods in the historical time-division work load data and the historical time-division work temperature data is analyzed, meanwhile, the influence of sample data with abrupt changes in the historical time-division work load data and the historical time-division work temperature data is considered, then the historical work temperature change data of the transformer is analyzed, and the historical winding hot spot temperature data of the transformer are extracted from the historical work temperature change data.
Specifically, as shown in fig. 2, fig. 2 shows a flowchart of analyzing historical winding hot spot temperature data of a transformer according to the historical workload data and the historical operating temperature data in the first embodiment of the invention, including the following steps:
s201, analyzing and obtaining linear correlation coefficients of the historical workload data and the historical working temperature data based on the historical workload data and the historical working temperature data;
in an optional implementation manner of this embodiment, the collected historical workload data and the historical working temperature data are divided into a plurality of historical time-division workload data and historical time-division working temperature data according to a preset time interval, the plurality of historical time-division workload data and the historical time-division working temperature data are drawn into a scatter diagram according to time nodes, a relation between corresponding times is observed and analyzed, and linear correlation coefficients of the historical workload data and the historical working temperature data are obtained based on a linear function analysis method.
Specifically, the calculation formula of the linear correlation coefficient of the historical workload data and the historical working temperature data comprises:
wherein r is 1 Is a linear correlation coefficient, U is the total number of samples, A i For the ith historical workload data sample, A 0 Mean value of historical workload data samples, B i For the ith historical operating temperature data sample, B 0 Mean values are historical operating temperature data samples.
S202, analyzing sample data based on the sudden change between the historical workload data and the historical working temperature data to obtain correction coefficients of the historical workload data and the historical working temperature data;
in an optional implementation manner of this embodiment, according to a scatter diagram drawn by the linear correlation coefficient of the historical workload data and the historical operating temperature data, data samples with abrupt changes in the plurality of historical time-division workload data and the historical time-division operating temperature data are analyzed and extracted, and correlation between the data samples with abrupt changes and time is observed and analyzed to obtain correction coefficients of the historical workload data and the historical operating temperature data.
Specifically, the calculation formula of the correction coefficient of the historical workload data and the historical working temperature data comprises:
wherein r is 2 For correction factor, V is the total number of samples of the abrupt change, A j For the jth workload collapse data sample, B j For the jth operating temperature dip data sample.
S203, analyzing and obtaining historical working temperature change data of the transformer based on the linear correlation coefficient and the correction coefficient;
in an alternative implementation manner of this embodiment, the probability of occurrence of the abrupt change data sample in the total number of samples is calculated and analyzed, and the historical operating temperature change coefficient of the transformer is obtained by combining the linear correlation coefficient and the correction coefficient analysis, so as to obtain the historical operating temperature change data of the transformer.
Specifically, the calculation formula of the historical operating temperature change coefficient includes:
wherein r is 3 For the historical operating temperature coefficient of variation, P (j) is the probability of occurrence of the abrupt data samples, U is the total number of samples, A i For the ith historical workload data sample, A 0 Mean value of historical workload data samples, B i For the ith historical operating temperature data sample, B 0 Mean value of historical working temperature data samples, V is total number of abrupt samples, A j For the jth workload collapse data sample, B j For the jth operating temperature dip data sample.
S204, extracting historical winding hot spot temperature data of the transformer from the historical working temperature change data.
In an alternative implementation of this embodiment, the historical winding hotspot temperature data of the transformer is extracted in combination with the historical operating temperature change coefficient.
S102, collecting real-time work load data and real-time work temperature data of a transformer;
in an alternative implementation of the present embodiment, the real-time workload data of the transformer is obtained based on a voltage sensor provided on the transformer, and the real-time operating temperature data of the transformer is obtained based on a fiber bragg grating sensor provided on the transformer.
Specifically, temperature rise tests are carried out on the transformer under different load rates, and real-time work load data and realization work temperature data of the transformer are collected.
The real-time working temperature data includes real-time hot spot position temperature data, real-time top layer oil temperature data and real-time bottom layer oil temperature data.
Specifically, real-time workload data is collected through a voltage sensor arranged on a coil of a transformer, and a real-time workload data change curve in a temperature rise test is obtained through analysis.
Further, the transformer is suitable for a mineral oil + cellulose system at 105 ℃ under constant load, according to IEC 60076-7, part 7 of the power transformer: the loading guide of the oil immersed power transformer provides that under the condition of variable load, the temperature of the hot spot position of the transformer is equal to the sum of the ambient temperature, the temperature rise of the top oil level of the oil tank relative to the ambient temperature and the temperature rise of the hot spot position relative to the top oil level of the oil tank, namely the temperature of the top oil level of the oil tank of the transformer and the temperature of the hot spot position when the transformer works, and in the embodiment, the corresponding real-time hot spot position temperature data, real-time top oil temperature data and real-time bottom oil temperature data of a plurality of positions of the transformer are extracted in different working time periods through fiber grating sensors arranged on each position of the oil tank of the transformer.
S103, a transformer winding hot spot temperature calculation model is established, and the real-time work load data and the real-time work temperature data are analyzed based on the transformer winding hot spot temperature calculation model to obtain real-time winding hot spot temperature data of the transformer;
in an alternative implementation manner of this embodiment, the transformer winding hot spot temperature calculation model includes a top-layer oil temperature heat path calculation model and a bottom-layer oil temperature heat path calculation model.
In an optional implementation manner of the present embodiment, as shown in fig. 3, fig. 3 shows a flowchart for obtaining real-time winding hot spot temperature data of a transformer based on a top-layer oil temperature heat path calculation model in the first embodiment of the present invention, including the following steps:
s301, establishing a top-layer oil temperature heat circuit calculation model;
in an alternative implementation manner of the embodiment, the top-layer oil temperature circuit calculation model is obtained by analogy through a thermoelectric analogy method by establishing an equivalent hot spot simulation loop model of the oil immersed transformer.
Specifically, the heat circuit generally comprises a heat source, a heat capacity, a nonlinear heat conduction and the like. The thermoelectric analog calculation process does not consider the conduction of heat inside a conductor, considers the heat generated by a winding to be uniformly distributed, and also considers the skin effect of the winding of the transformer, and the heat exchange mode of the winding and the surrounding oil flow is mainly heat convection, so that considering all physical properties of the winding of the transformer can be represented by one node.
Specifically, according to differential equations of the thermal circuit
Wherein p=q 1 +q 2 ，C＝C 1 +C 2 +C 3 +C 4 ，q 1 For transformer winding coil loss, q 2 Is the core loss of the transformer, C is the total heat capacity of the transformer, C 1 C is the heat capacity of the winding of the transformer 2 C is the heat capacity of the iron core of the transformer 3 C is the heat capacity of the oil tank and other heating devices of the transformer 4 Is the heat capacity of oil and other heating devices of the transformer, R is the resistance of a transformer winding, and theta 1 For the top layer oil temperature>
Is an oil viscosity gradient.
More, consider the loss under the rated load condition, and the load and temperature change usually have less influence on the iron loss, obtain the load loss, the calculation formula includes:
wherein P is 1 P is the load loss 2 For load voltage loss, P 3 For the oil tank and the oil loss,
temperature rise of top oil for hot spot position temperature, +.>
Temperature rise of top oil for rated hot spot temperature, θ 1 Is the top layer oil temperature, theta 2 Is the hot spot location temperature.
More, the calculation formula of the top-layer oil temperature heat path calculation model comprises:
wherein P is 1 K is the load factor, R is the transformer winding resistance, mu 1 B is a nonlinear index of the oil circulation state,
for the temperature rise of top oil under rated load, tau 1 Is the thermal time constant, theta, of the oil at rated load 1 Is the top layer oil temperature.
S302, analyzing nonlinear thermal resistance data based on a transformer to obtain a correction coefficient of the top-layer oil temperature heat circuit calculation model;
in an alternative implementation manner of this embodiment, in the calculation process of the top oil temperature, the heat dissipation effect of the heat sink needs to be considered, and the three types of surface convection heat dissipation resistance, oil duct heat transfer resistance and oil flow heat dissipation resistance of the general finned radiator are connected in series to form the overall convection heat dissipation resistance of the radiator.
Specifically, according to the Ji De-Taylor formula, each heat dissipation resistance can be calculated:
R 5 ＝R 1 +R 2 +R 3 +R 4 ，
wherein R is 1 R is the heat resistance of surface convection heat radiation 2 For heat transfer resistance of oil duct, R 3 R is the heat radiation resistance of horizontal oil flow 4 Is vertical oil flow heat radiation resistance, R 5 Is nonlinear thermal resistance, n is the number of radiating fins of the finned radiator, L 1 Is the length of the vertical oil flow channel, H is the height of the vertical oil flow channel, H 1 H is the average heat exchange coefficient 2 Is the heat exchange coefficient of heat dissipation of oil flow, A is the heat transfer current of an oil duct, D is the diameter of a horizontal oil flow channel, L 2 And M is the thickness of the vertical oil flow channel.
S303, correcting the top-layer oil temperature heat path calculation model based on the correction coefficient to obtain a top-layer oil temperature heat path calculation improved model;
in an optional implementation manner of this embodiment, the top-layer oil-temperature heat circuit calculation model is modified based on a correction coefficient, where the load loss is optimized as follows:
wherein P is 1′ P for corrected load loss 2 For load voltage loss, P 4 Is the superposition loss of the oil tank, the oil and the vortex,
temperature rise of top oil for hot spot position temperature, +.>
To maximum hot spot temperature to top oil temperature rise, θ 1 Is the top layer oil temperature, theta 2 Is a hot spotAnd (5) setting the temperature.
More, the calculation formula of the top-layer oil temperature heat path calculation improved model comprises:
wherein K is a load factor, P 1′ For corrected load loss, θ 1 Is the top layer oil temperature, theta 2 Mu, temperature of hot spot position 1 In order to change the viscosity of the oil,
for rated hot spot temperature to top oil temperature rise, a is empirical index, ρ θ Is the oil density coefficient, τ 2 Is the transformer winding time constant.
S304, analyzing the real-time work load data and the real-time work temperature data based on the top-layer oil temperature heat circuit calculation improved model to obtain real-time winding hot spot temperature data of the transformer.
In an optional implementation manner of this embodiment, the real-time workload data and the real-time working temperature data of different time periods are analyzed based on the top-layer oil-temperature heat circuit calculation improved model, and real-time winding hot spot temperature data of each time period of the transformer is calculated.
In an alternative implementation manner of the present embodiment, as shown in fig. 4, fig. 4 shows a flowchart for obtaining real-time winding hot spot temperature data of a transformer based on a bottom oil temperature heat path calculation model in the first embodiment of the present invention, including the following steps:
s401, establishing a bottom oil temperature heat circuit calculation model;
in an alternative implementation of this embodiment, the calculation model of the bottom oil temperature circuit is obtained by analogy using thermoelectric analogy by establishing an equivalent hot spot simulation loop model of the oil immersed transformer.
Specifically, the calculation formula of the bottom oil temperature heat path calculation model includes:
wherein K is a load factor, P 1′ For corrected load loss, θ 3 Is the bottom oil temperature, theta 2 The temperature of the hot spot position is a empirical index, and C is the total heat capacity of the transformer.
S402, analyzing the real-time work load data and the real-time work temperature data based on the bottom oil temperature heat circuit calculation model to obtain real-time winding hot spot temperature data of the transformer.
In an optional implementation manner of this embodiment, the real-time workload data and the real-time working temperature data of different time periods are analyzed based on the bottom oil temperature circuit calculation model, and the real-time winding hot spot temperature data of each time period of the transformer is calculated.
S104, analyzing and obtaining working winding hot spot temperature data of the transformer based on the historical winding hot spot temperature data and the real-time winding hot spot temperature data.
In an optional implementation manner of this embodiment, the historical winding hot spot temperature data and the real-time winding hot spot temperature data are compared and analyzed, and the thermal characteristic parameters of the transformer are optimized, so that the working winding hot spot temperature data of the transformer are obtained through analysis.
In an alternative implementation of the present embodiment, the thermal characteristic parameters of the transformer are optimized based on the L-M algorithm (Levenberg-Marquardt).
Specifically, the L-M algorithm is an estimation method of regression parameter least square estimation in nonlinear regression, and a method of integrating a steepest descent method and a linearization method (Taylor series). Since the steepest descent method is suitable for the case where the parameter estimation value is far from the optimal value at the beginning of the iteration, whereas the linearization method, i.e., the gauss newton method is suitable for the later stage of the iteration, the parameter estimation value is in the range close to the optimal value. The two methods can be combined to find the optimal value relatively quickly, and have the advantages of high convergence speed and small mean square error.
In summary, the first embodiment of the invention provides a method for calculating the hot spot temperature of the working winding of an oil-immersed transformer, which is used for collecting historical working load data and historical working temperature data of the transformer, analyzing and obtaining the hot spot temperature data of the historical winding of the transformer by calculating linear correlation coefficients and correction coefficients of the historical working load data and the historical working temperature data, fully considering the influence of suddenly changed sample data on a calculation result, improving the calculation precision and providing reference for calculating the hot spot temperature data of the winding; the real-time work load data and the real-time work temperature data of the transformer are obtained based on the voltage sensor and the fiber bragg grating sensor, so that the collected data are more accurate; respectively establishing a top-layer oil temperature heat circuit calculation model and a bottom-layer oil temperature heat circuit calculation model, synthesizing calculation results of the two models to obtain real-time winding hot spot temperature data of the transformer, and improving calculation accuracy of the real-time winding hot spot temperature data; and comparing and verifying the real-time winding hot spot temperature data with the historical winding hot spot temperature data, so that the efficiency and the accuracy of the calculation of the working winding hot spot temperature of the oil-immersed transformer are improved, and the method has higher application value.
Example two
The embodiment of the invention also relates to a device for calculating the hot spot temperature of the working winding of the oil-immersed transformer, as shown in fig. 5, fig. 5 shows a schematic diagram of the device for calculating the hot spot temperature of the working winding of the oil-immersed transformer in the second embodiment of the invention, and the device comprises:
the historical data analysis module 10 is used for acquiring historical work load data and historical work temperature data of the transformer and analyzing and obtaining historical winding hot spot temperature data of the transformer according to the historical work load data and the historical work temperature data;
a real-time data collection module 20, wherein the real-time data collection module 20 is used for collecting real-time work load data and real-time work temperature data of the transformer;
the real-time data analysis module 30 is used for establishing a transformer winding hot spot temperature calculation model, analyzing the real-time work load data and the real-time work temperature data based on the transformer winding hot spot temperature calculation model, and obtaining real-time winding hot spot temperature data of the transformer;
and the data comprehensive analysis module 40 is used for analyzing and obtaining working winding hot spot temperature data of the transformer based on the historical winding hot spot temperature data and the real-time winding hot spot temperature data.
In summary, the second embodiment of the present invention provides a device for calculating a hot spot temperature of a working winding of an oil-immersed transformer, which is configured to perform the above method for calculating a hot spot temperature of a working winding of an oil-immersed transformer, collect historical workload data and historical working temperature data of the transformer, analyze and obtain the hot spot temperature data of the historical winding of the transformer by calculating a linear correlation coefficient and a correction coefficient of the historical workload data and the historical working temperature data, fully consider the influence of suddenly changed sample data on a calculation result, improve calculation accuracy, and provide a reference for calculating the hot spot temperature data of the winding; the real-time work load data and the real-time work temperature data of the transformer are obtained based on the voltage sensor and the fiber bragg grating sensor, so that the collected data are more accurate; respectively establishing a top-layer oil temperature heat circuit calculation model and a bottom-layer oil temperature heat circuit calculation model, synthesizing calculation results of the two models to obtain real-time winding hot spot temperature data of the transformer, and improving calculation accuracy of the real-time winding hot spot temperature data; and comparing and verifying the real-time winding hot spot temperature data with the historical winding hot spot temperature data, so that the efficiency and the accuracy of the calculation of the working winding hot spot temperature of the oil-immersed transformer are improved, and the method has higher application value.
Those of ordinary skill in the art will appreciate that all or part of the steps in the various methods of the above embodiments may be implemented by a program to instruct related hardware, the program may be stored in a computer readable storage medium, and the storage medium may include: read Only Memory (ROM), random access Memory (RAM, random Access Memory), magnetic or optical disk, and the like.
In addition, the foregoing has described in detail embodiments of the present invention, the principles and embodiments of the present invention have been described herein with reference to specific examples, the foregoing examples being provided to facilitate the understanding of the method of the present invention and the core idea thereof; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (10)
1. A method for calculating the hot spot temperature of an oil immersed transformer working winding, the method comprising:
acquiring historical work load data and historical work temperature data of a transformer, and analyzing and obtaining historical winding hot spot temperature data of the transformer according to the historical work load data and the historical work temperature data;
collecting real-time work load data and real-time work temperature data of the transformer;
establishing a transformer winding hot spot temperature calculation model, and analyzing the real-time work load data and the real-time work temperature data based on the transformer winding hot spot temperature calculation model to obtain real-time winding hot spot temperature data of the transformer;
and analyzing and obtaining working winding hot spot temperature data of the transformer based on the historical winding hot spot temperature data and the real-time winding hot spot temperature data.
2. The method of claim 1, wherein the obtaining historical operating load data and historical operating temperature data of the transformer comprises:
and extracting the historical work load data and the historical work temperature data of the transformer from the historical work data of the transformer.
3. The method of claim 1, wherein analyzing the historical winding hotspot temperature data of the transformer from the historical workload data and the historical operating temperature data comprises:
analyzing and obtaining linear correlation coefficients of the historical workload data and the historical working temperature data based on the historical workload data and the historical working temperature data;
obtaining correction coefficients of the historical workload data and the historical working temperature data based on sample data analysis of abrupt changes between the historical workload data and the historical working temperature data;
analyzing and obtaining historical working temperature change data of the transformer based on the linear correlation coefficient and the correction coefficient;
and extracting historical winding hot spot temperature data of the transformer from the historical operating temperature change data.
4. The method of oil immersed transformer working winding hotspot temperature calculation of claim 1, wherein collecting real-time workload data and real-time working temperature data of the transformer comprises:
real-time working load data of the transformer are obtained based on a voltage sensor arranged on the transformer, and real-time working temperature data of the transformer are obtained based on a fiber bragg grating sensor arranged on the transformer.
5. The method of claim 4, wherein the real-time operating temperature data comprises real-time hot spot location temperature data, real-time top layer oil temperature data, real-time bottom layer oil temperature data.
6. The method of claim 5, wherein the establishing a transformer winding hotspot temperature calculation model, analyzing the real-time workload data and the real-time operating temperature data based on the transformer winding hotspot temperature calculation model, and obtaining the real-time winding hotspot temperature data of the transformer comprises:
establishing a top-layer oil temperature heat path calculation model;
obtaining a correction coefficient of the top-layer oil temperature heat circuit calculation model based on nonlinear thermal resistance data analysis of the transformer;
correcting the top-layer oil temperature heat circuit calculation model based on the correction coefficient to obtain a top-layer oil temperature heat circuit calculation improved model;
and analyzing the real-time work load data and the real-time work temperature data based on the top-layer oil temperature heat circuit calculation improved model to obtain real-time winding hot spot temperature data of the transformer.
7. The method for calculating the hot spot temperature of the working winding of the oil immersed transformer according to claim 6, wherein the calculation formula of the top-layer oil temperature heat circuit calculation improvement model comprises:
wherein K is a load factor, P 1′ For corrected load loss, θ 1 Is the top layer oil temperature, theta 2 Mu, temperature of hot spot position 1 In order to change the viscosity of the oil,
for rated hot spot temperature to top oil temperature rise, a is empirical index, ρ θ Is the oil density coefficient, τ 2 Is the transformer winding time constant.
8. The method for calculating the hot spot temperature of the working winding of the oil immersed transformer according to claim 5, wherein the establishing a hot spot temperature calculation model of the transformer winding, analyzing the real-time working load data and the real-time working temperature data based on the hot spot temperature calculation model of the transformer winding, and obtaining the hot spot temperature data of the real-time winding of the transformer further comprises:
establishing a bottom oil temperature heat path calculation model;
and analyzing the real-time work load data and the real-time work temperature data based on the bottom oil temperature heat circuit calculation model to obtain real-time winding hot spot temperature data of the transformer.
9. The method for calculating the hot spot temperature of the working winding of the oil immersed transformer according to claim 8, wherein the calculation formula of the bottom oil temperature heat circuit calculation model comprises:
wherein K is a load factor, P 1′ For corrected load loss, θ 3 Is the bottom oil temperature, theta 2 The temperature of the hot spot position is a empirical index, and C is the total heat capacity of the transformer.
10. An oil immersed transformer work winding hot spot temperature calculation device, characterized in that the device comprises:
the historical data analysis module is used for acquiring historical work load data and historical work temperature data of the transformer and analyzing and obtaining historical winding hot spot temperature data of the transformer according to the historical work load data and the historical work temperature data;
the real-time data collection module is used for collecting real-time work load data and real-time work temperature data of the transformer;
the real-time data analysis module is used for establishing a transformer winding hot spot temperature calculation model, analyzing the real-time work load data and the real-time work temperature data based on the transformer winding hot spot temperature calculation model, and obtaining real-time winding hot spot temperature data of the transformer;
and the data comprehensive analysis module is used for analyzing and obtaining working winding hot spot temperature data of the transformer based on the historical winding hot spot temperature data and the real-time winding hot spot temperature data.
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