CN113569501B - Method and device for determining average temperature gradient of winding and electronic equipment - Google Patents
Method and device for determining average temperature gradient of winding and electronic equipment Download PDFInfo
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Abstract
The application discloses a method and a device for determining an average temperature gradient of a winding and electronic equipment, in particular to a method for constructing a heat exchange process loop model of internal heat exchange of oil immersed inductive power equipment; constructing a flow power calculation model of oil flow in the oil immersed inductive power equipment according to the heat exchange process loop model; constructing a flow resistance calculation model of the oil flow according to the heat exchange process loop model; performing iterative computation on the flow power computing model and the flow resistance computing model to obtain current flow power and current flow resistance, and determining that the oil immersed inductive power equipment is in a dynamic resistance balance state when the error of the current flow power and the current flow resistance is smaller than a preset error threshold value; and calculating the average temperature gradient of the windings of the oil immersed inductive power equipment in the dynamic resistance balance state. The heat exchange coefficient with experience coefficient property is not needed in the treatment scheme, and objectivity is high, so that the reliability and economy of the design of the inductive power equipment are improved.
Description
Technical Field
The application relates to the technical field of electric equipment, in particular to a method and a device for determining an average temperature gradient of a winding and electronic equipment.
Background
When determining the average temperature gradient of the windings of the inductive power equipment such as a transformer, a reactor and the like, as the structure of the inductive power equipment is continuously improved along with the continuous development of the inductive power equipment, the calculation accuracy is lower and lower when the original heat exchange coefficient with the characteristic of an empirical coefficient is adopted to calculate the average temperature gradient of the windings of the inductive power equipment, and the reliability and the economy of the design of the inductive power equipment based on the average temperature gradient of the windings are poor.
Disclosure of Invention
In view of the above, the present application provides a method, an apparatus and an electronic device for determining a winding average temperature gradient, which are used for obtaining a winding average temperature gradient with higher accuracy, so as to improve the reliability and economy of the design of an inductive power device.
In order to achieve the above object, the following solutions have been proposed:
a method of determining a winding average temperature gradient for an electronic device having data computing and information processing capabilities, the method comprising the steps of:
constructing a heat exchange process loop model of internal heat exchange of the oil immersed inductive power equipment;
constructing a flow power calculation model of oil flow in the oil immersed inductive power equipment according to the heat exchange process loop model;
constructing a flow resistance calculation model of the oil flow according to the heat exchange process loop model;
performing iterative computation on the flow power calculation model and the flow resistance calculation model to obtain current flow power and current flow resistance, and determining that the oil immersed inductive power equipment is in a dynamic resistance balance state when the error between the current flow power and the current flow resistance is smaller than a preset error threshold value;
and calculating the average temperature gradient of the winding of the oil-immersed inductive power equipment in the dynamic resistance balance state.
Optionally, the oil immersed inductive power device is divided into an external heat exchange and the internal heat exchange with an oil tank wall as a boundary.
Optionally, the constructing a flow power calculation model of the oil flow in the oil immersed inductive power device according to the heat exchange process loop model includes the steps of:
and establishing the specific gravity-temperature differential of the insulating liquid which participates in heat exchange in the winding from the angle of generating buoyancy from the liquid density change according to the Boussinesq principle, and integrating a process loop to obtain the flow power calculation model.
Optionally, the constructing a flow resistance calculation model of the oil flow according to the heat exchange circuit model includes the steps of:
and acquiring the winding geometric parameters of the oil immersed inductive power equipment, carrying out equivalent treatment on the characteristic dimensions of the oil ducts which participate in heat exchange in the windings according to the winding geometric parameters and applying a similar principle, and constructing the flow resistance calculation model according to the equivalent dimensions.
Optionally, the calculating the winding average temperature gradient of the oil immersed inductive power device in the dynamic resistance balance state includes the steps of:
calculating a convective heat transfer coefficient between a winding of the oil immersed inductive power device and insulating oil;
and calculating the average temperature gradient of the winding according to the convection heat transfer coefficient.
A winding average temperature gradient determining apparatus for use in an electronic device having data computing and information processing capabilities, the determining apparatus comprising:
the first construction module is configured to construct a heat exchange process loop model of internal heat exchange of the oil immersed inductive power device;
the second construction module is configured to construct a flow power calculation model of the oil flow in the oil immersed inductive power device according to the heat exchange process loop model;
a third building module configured to build a flow resistance calculation model of the oil flow from the heat exchange process loop model;
the iterative computation module is configured to perform iterative computation on the flow power computation model and the flow resistance computation model to obtain current flow power and current flow resistance, and when the error between the current flow power and the current flow resistance is smaller than a preset error threshold value, the oil immersed inductive power equipment is determined to be in a dynamic resistance balance state;
a gradient calculation module configured to calculate a winding average temperature gradient of the oil-immersed inductive power device in the dynamic resistance equilibrium state.
Optionally, the oil immersed inductive power device is divided into an external heat exchange and the internal heat exchange with an oil tank wall as a boundary.
Optionally, the second construction module is specifically configured to generate a floating force angle from the liquid density change according to the Boussinesq principle, establish a specific gravity-temperature differential of insulating liquid inside the winding and participating in heat exchange, and perform process loop integration to obtain the flow power calculation model.
Optionally, the third construction module is specifically configured to obtain a winding geometry parameter of the oil immersed inductive power device, perform equivalent processing on a characteristic size of an oil duct participating in heat exchange inside a winding according to the winding geometry parameter and applying a similar principle, and construct the flow resistance calculation model according to the equivalent size.
Optionally, the gradient calculation module includes:
a first calculation unit configured to calculate a convective heat transfer coefficient between a winding of the oil-immersed inductive power device and insulating oil;
the second calculation unit is not configured to calculate the winding average temperature gradient from the convective heat transfer coefficient.
An electronic device is provided with a determination means of the winding average temperature gradient as described above.
An electronic device comprising at least one processor and a memory coupled to the processor, wherein:
the memory is used for storing a computer program or instructions;
the processor is configured to execute the computer program or instructions to cause the electronic device to implement the method of determining a winding average temperature gradient as described above.
From the technical scheme, the application discloses a method and a device for determining the average temperature gradient of a winding and electronic equipment, in particular to a heat exchange process loop model for constructing the internal heat exchange of oil immersed inductive power equipment; constructing a flow power calculation model of oil flow in the oil immersed inductive power equipment according to the heat exchange process loop model; constructing a flow resistance calculation model of the oil flow according to the heat exchange process loop model; performing iterative computation on the flow power computing model and the flow resistance computing model to obtain current flow power and current flow resistance, and determining that the oil immersed inductive power equipment is in a dynamic resistance balance state when the error of the current flow power and the current flow resistance is smaller than a preset error threshold value; and calculating the average temperature gradient of the windings of the oil immersed inductive power equipment in the dynamic resistance balance state. The heat exchange coefficient with the experience coefficient property is not needed in the processing scheme, and objectivity is high, so that the winding average temperature gradient with high accuracy can be obtained, and the reliability and the economy of the design of the inductive power equipment are improved.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, 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 flow chart of a method for determining a winding average temperature gradient according to an embodiment of the present application;
fig. 2 is a flow process of insulating oil of the oil-immersed inductive power device of the present application;
FIG. 3 is a graph of internal heat exchange insulator liquid height versus temperature according to the present application;
FIG. 4 is a block diagram of a device for determining the average temperature gradient of a winding according to an embodiment of the present application;
fig. 5 is a block diagram of an electronic device according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application 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 application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Example 1
FIG. 1 is a flow chart of a method for determining a winding average temperature gradient according to an embodiment of the present application.
The determining method provided by the embodiment is applied to electronic equipment with data calculation and information processing, such as a server or a computer, and the determining method is used for calculating the average temperature gradient of windings of oil-immersed inductive power equipment such as a transformer and an inductor according to related parameters. The oil immersed inductive power equipment in the embodiment comprises an oil tank and a winding coated in the oil tank, wherein insulating oil with insulating and heat dissipation functions is arranged in the oil tank. The insulating oil is mineral oil or other liquid capable of insulating and radiating heat.
The oil immersed inductive power equipment of the application works under a non-OD cooling working condition, namely adopts a natural heat dissipation mode to dissipate heat. The OD cooling mode is an operation mode by adopting a forced oil circulation guiding structure.
As shown in FIG. 1, the method for determining the average temperature gradient of the winding provided by the application comprises the following steps:
s1, constructing a heat exchange process loop model of internal heat exchange.
And constructing a heat exchange process loop model of the internal heat exchange of the oil immersed inductive power equipment to be determined. In the application, the oil immersed inductive power equipment is divided into an internal heat exchange part and an external heat exchange part by taking the oil tank wall as a boundary, and as shown in fig. 2, the inductive power equipment comprises an oil tank 2, a winding 1 arranged in the oil tank and an external heat exchange device 3.
Based on the precondition, a heat exchange loop model of internal heat exchange is constructed, and the model specifically comprises the following steps: insulating oil for cooling the winding enters from the bottom of the winding, flows out from the top of the winding after heat exchange with the winding, and completes oil circuit circulation in the oil tank.
Wherein, the B '-A' virtual oil flow path and the C '-D' virtual oil flow path. The two virtual oil flow paths flow in opposite directions, the flow rates are the same, the temperatures of B 'and C' are the same, and the temperatures of A 'and D' are the same. The external heat exchange affects the temperature of the insulating liquid at the inner wall of the oil tank through the temperature at the outer wall of the oil tank. Under the given conditions of the external cooling device and the heat exchange conditions, the flow state and the heat exchange state of the internal heat exchange are not influenced by the external heat exchange; the internal heat exchange forms an independent insulating liquid flow heat exchange process loop.
S2, constructing a flow power calculation model according to the heat exchange process loop model.
After a heat exchange process loop model of the oil immersed inductive power equipment is determined, a flow power calculation model is built according to the model. The flow dynamics calculation model is shown in fig. 3.
Wherein, the point A is the winding inlet; the point B is the outlet of the winding; the point B' is the same horizontal height as the point B and is far away from a certain position of the winding outlet; the point A' is the same level as the point A and is far away from the position of the winding inlet. Wherein B '-a' constitutes a virtual oil flow path.
The a-B process is a process in which the insulating liquid flows into the windings to be heated, and the temperature thereof increases linearly with the increase in height; B-B' is a process of mixing high temperature at the outlet of the winding with surrounding cold oil, the height of the process is unchanged, and the temperature is suddenly changed to the top temperature of the oil tank; b ' -A ' is a virtual oil flow path, the temperature of which decreases linearly with decreasing height, and A ' is the bottom temperature of the oil tank; a' -A, the level and temperature of which are consistent, coincide in the height-temperature process loop.
According to the Boussinesq principle, the pressure between any high infinitesimal in the internal heat exchange process is as follows:
dp＝(γ 1 -γ 2 )dh (1)
in the formula (1), gamma 1 ，γ 2 The specific gravity of the insulating liquid between two points in the infinitesimal can be expressed as:
γ 1 ＝γ 0 *(1-β 0 t 1 ) (2)
γ 2 ＝γ 0 *(1-β 0 t 2 ) (3)
in the formulae (2) - (3), gamma 0 ，β 0 Specific gravity and volume expansion coefficient of insulating liquid at 273.15K absolute temperature, t 1 ，t 2 Is the temperature within the infinitesimal.
Bringing the formulae (2) to (3) into the formula (1) to obtain
dp＝γ 0 β 0 *(t 2 -t 1 )dh＝γ 0 β 0 *Δtdh (4)
As described above, the flow power in the internal heat exchange process loop can be obtained by integrating the internal heat exchange process.
∑p＝∫dp＝γ 0 β 0 ∮t(h)dh＝γ 0 β 0 *S ABB′A′A (5)
In the formula (5), S ABB′A′A I.e. the triangular area of ABB' in fig. 2.
S3, constructing a flow resistance calculation model according to the heat exchange loop model.
On the basis of the heat exchange process loop model, a flow resistance calculation model of the oil immersed inductive power equipment is constructed. The specific process is as follows:
the energy conservation law is applied to the heat exchange process of the winding and the insulating liquid, and the flow of the insulating liquid participating in heat exchange is determined according to the oil temperature rise value of the A-B process assumed in the third step:
in the formula (6), Q is the oil flow rate of heat exchange between the winding and the insulating liquid, and the unit is m 3 S; p is the loss of the winding, including resistance loss and eddy current loss, and the unit is W; c is the specific heat capacity of the insulating liquid, and the unit is J/(kg.K); Δt (delta t) AB The oil temperature rise value for the A-B process is given in K.
After Q is obtained, rootAccording to the winding geometry, the oil flow velocity inside the winding is obtained so as to calculate the inter-cake oil passage on-way resistance loss (F 1 ) Loss of main insulation path along resistance (F 2 ) Local resistance loss of winding inlet and outlet (F 3 ) Local drag loss at winding oil baffle (F 4 ). And adding the resistance losses to obtain the flow resistance loss sigma F in the process loop.
∑F＝F 1 +F 2 +F 3 +F 4 (7)
S4, carrying out iterative computation on the flow power computing model and the flow resistance computing model.
And (3) obtaining the current flow power and the current flow resistance through iterative calculation of the two calculation models, and determining that the oil immersed inductive power equipment is in a dynamic resistance balance state when the error of the current flow power and the current flow resistance is smaller than a preset error threshold (for example, 0.1 Pa). The specific calculation process is as follows:
by assuming the temperature rise value of the A-B process oil, adopting the principle of dichotomy, iteratively calculating formulas (5) and (7), and when the absolute value of the difference between the formulas is smaller than a given value (for example, 0.1), considering the flow field balance in the internal heat exchange process, and ending the iteration. At this time, the insulating liquid in the winding satisfies energy conservation and mass conservation in the running process of the transformer, namely in a dynamic resistance balance state.
S5, calculating the average temperature gradient of the winding in the dynamic resistance balance state.
When the oil immersed inductive power equipment is in the dynamic resistance balance state, calculating the average temperature gradient of the winding in the state. The specific process is as follows:
firstly, adopting a corrected Seider-Tate formula to calculate a winding convection heat exchange coefficient:
in the formula (8), nu is Knoop number, re is Reynolds number, pr is Plantt number, d is hydraulic diameter, unit m, L is characteristic length, unitm, μ is the viscosity coefficient, unit m 2 And/s. The subscript f represents an insulating liquid and the subscript w represents a winding.
The convective heat transfer coefficient of the winding with the insulating liquid can be expressed as:
in the formula (9), h represents a convection heat transfer coefficient, and the unit is W/(m) 2 K), lambda is the thermal conductivity of the insulating liquid in W/(m.K).
Then, under the condition that the convection heat transfer coefficient of the winding is obtained, calculating the average temperature gradient of the winding, wherein the specific process is as follows:
according to the winding geometry, calculating the surface area of the winding in contact with oil, namely the heat exchange area, and obtaining the average surface heat flow density of the winding so as to obtain the average temperature gradient of the insulating liquid in the winding and the insulating cylinder
In the formula (10), deltaθ AB The unit is K, which is the average temperature difference between the winding and the insulating liquid in the insulating cylinder.
According to the definition of GB1094.2-2013, the average temperature gradient of windings of a liquid-immersed transformer and a reactor is the difference between the average temperature of the windings and the average temperature of insulating liquid, namely the average temperature difference between the windings and the insulating liquid in an insulating cylinder plus the average temperature difference between the insulating liquid inside and outside the insulating cylinder:
Δθ＝Δθ AB +0.5*(Δt AB -Δt A′B′ )*ξ (11)
in the formula (11), delta theta is the average temperature gradient of the winding, and the unit is K; θ m The unit is K for the average temperature rise of the insulating liquid; ζ is a coefficient dependent on the winding position.
According to the technical scheme, the application provides a method for determining the average temperature gradient of a winding, which is applied to electronic equipment, in particular to a heat exchange process loop model for constructing internal heat exchange of oil immersed inductive power equipment; constructing a flow power calculation model of oil flow in the oil immersed inductive power equipment according to the heat exchange process loop model; constructing a flow resistance calculation model of the oil flow according to the heat exchange process loop model; performing iterative computation on the flow power computing model and the flow resistance computing model to obtain current flow power and current flow resistance, and determining that the oil immersed inductive power equipment is in a dynamic resistance balance state when the error of the current flow power and the current flow resistance is smaller than a preset error threshold value; and calculating the average temperature gradient of the windings of the oil immersed inductive power equipment in the dynamic resistance balance state. The heat exchange coefficient with the experience coefficient property is not needed in the processing scheme, and objectivity is high, so that the winding average temperature gradient with high accuracy can be obtained, and the reliability and the economy of the design of the inductive power equipment are improved.
Example two
Fig. 4 is a block diagram of a device for determining a winding average temperature gradient according to an embodiment of the present application.
The determining device provided in this embodiment is applied to an electronic device with data calculation and information processing, such as a server or a computer, and the determining device is used for calculating the winding average temperature gradient of an oil-immersed inductive power device such as a transformer and an inductor according to related parameters, and can be understood as the server or the computer itself, and the functional module understood as the server or the computer is obtained. The oil immersed inductive power equipment in the embodiment comprises an oil tank and a winding coated in the oil tank, wherein insulating oil with insulating and heat dissipation functions is arranged in the oil tank. The insulating oil is mineral oil or other liquid capable of insulating and radiating heat.
The oil immersed inductive power equipment of the application works under a non-OD cooling working condition, namely adopts a natural heat dissipation mode to dissipate heat. The OD cooling mode is an operation mode by adopting a forced oil circulation guiding structure.
As shown in fig. 4, the device for determining the average temperature gradient of the winding provided by the application comprises a first construction module 10, a second construction module 20, a third construction module 30, an iterative calculation module 40 and a gradient calculation module 50.
The first framework module is used for constructing a heat exchange process loop model of internal heat exchange.
And constructing a heat exchange process loop model of the internal heat exchange of the oil immersed inductive power equipment to be determined. In the application, the oil immersed inductive power equipment is divided into an internal heat exchange part and an external heat exchange part by taking the oil tank wall as a boundary, and as shown in fig. 2, the inductive power equipment comprises an oil tank 2, a winding 1 arranged in the oil tank and an external heat exchange device 3.
Based on the precondition, a heat exchange loop model of internal heat exchange is constructed, and the model specifically comprises the following steps: insulating oil for cooling the winding enters from the bottom of the winding, flows out from the top of the winding after heat exchange with the winding, and completes oil circuit circulation in the oil tank.
Wherein, the B '-A' virtual oil flow path and the C '-D' virtual oil flow path. The two virtual oil flow paths flow in opposite directions, the flow rates are the same, the temperatures of B 'and C' are the same, and the temperatures of A 'and D' are the same. The external heat exchange affects the temperature of the insulating liquid at the inner wall of the oil tank through the temperature at the outer wall of the oil tank. Under the given conditions of the external cooling device and the heat exchange conditions, the flow state and the heat exchange state of the internal heat exchange are not influenced by the external heat exchange; the internal heat exchange forms an independent insulating liquid flow heat exchange process loop.
The second construction module is used for constructing a flow power calculation model according to the heat exchange process loop model.
After a heat exchange process loop model of the oil immersed inductive power equipment is determined, a flow power calculation model is built according to the model. The flow dynamics calculation model is shown in fig. 3.
Wherein, the point A is the winding inlet; the point B is the outlet of the winding; the point B' is the same horizontal height as the point B and is far away from a certain position of the winding outlet; the point A' is the same level as the point A and is far away from the position of the winding inlet. Wherein B '-a' constitutes a virtual oil flow path.
The a-B process is a process in which the insulating liquid flows into the windings to be heated, and the temperature thereof increases linearly with the increase in height; B-B' is a process of mixing high temperature at the outlet of the winding with surrounding cold oil, the height of the process is unchanged, and the temperature is suddenly changed to the top temperature of the oil tank; b ' -A ' is a virtual oil flow path, the temperature of which decreases linearly with decreasing height, and A ' is the bottom temperature of the oil tank; a' -A, the level and temperature of which are consistent, coincide in the height-temperature process loop.
According to the Bouss inesq principle, the pressure between any high infinitesimal in the internal heat exchange process is as follows:
dp＝(γ 1 -γ 2 )dh (1)
in the formula (1), gamma 1 ，γ 2 The specific gravity of the insulating liquid between two points in the infinitesimal can be expressed as:
γ 1 ＝γ 0 *(1-β 0 t 1 ) (2)
γ 2 ＝γ 0 *(1-β 0 t 2 ) (3)
in the formulae (2) - (3), gamma 0 ，β 0 Specific gravity and volume expansion coefficient of insulating liquid at 273.15K absolute temperature, t 1 ，t 2 Is the temperature within the infinitesimal.
Bringing the formulae (2) to (3) into the formula (1) to obtain
dp＝γ 0 β 0 *(t 2 -t 1 )dh＝γ 0 β 0 *Δtdh (4)
As described above, the flow power in the internal heat exchange process loop can be obtained by integrating the internal heat exchange process.
∑p＝∫dp＝γ 0 β 0 ∮t(h)dh＝γ 0 β 0 *S ABB′A′A (5)
In the formula (5), S ABB′A′A I.e. the triangular area of ABB' in fig. 2.
The third construction module is used for constructing a flow resistance calculation model according to the heat exchange loop model.
On the basis of the heat exchange process loop model, a flow resistance calculation model of the oil immersed inductive power equipment is constructed. The specific process is as follows:
the energy conservation law is applied to the heat exchange process of the winding and the insulating liquid, and the flow of the insulating liquid participating in heat exchange is determined according to the oil temperature rise value of the A-B process assumed in the third step:
in the formula (6), Q is the oil flow rate of heat exchange between the winding and the insulating liquid, and the unit is m 3 S; p is the loss of the winding, including resistance loss and eddy current loss, and the unit is W; c is the specific heat capacity of the insulating liquid, and the unit is J/(kg.K); Δt (delta t) AB The oil temperature rise value for the A-B process is given in K.
After Q is obtained, the oil flow velocity inside the winding is obtained according to the winding geometry, and then the inter-cake oil passage on-way resistance loss inside the winding is calculated (F 1 ) Loss of main insulation path along resistance (F 2 ) Local resistance loss of winding inlet and outlet (F 3 ) Local drag loss at winding oil baffle (F 4 ). And adding the resistance losses to obtain the flow resistance loss sigma F in the process loop.
∑F＝F 1 +F 2 +F 3 +F 4 (7)
The iterative computation module is used for carrying out iterative computation on the flow power computation model and the flow resistance computation model.
And (3) obtaining the current flow power and the current flow resistance through iterative calculation of the two calculation models, and determining that the oil immersed inductive power equipment is in a dynamic resistance balance state when the error of the current flow power and the current flow resistance is smaller than a preset error threshold (for example, 0.1 Pa). The specific calculation process is as follows:
by assuming the temperature rise value of the A-B process oil, adopting the principle of dichotomy, iteratively calculating formulas (5) and (7), and when the absolute value of the difference between the formulas is smaller than a given value (for example, 0.1), considering the flow field balance in the internal heat exchange process, and ending the iteration. At this time, the insulating liquid in the winding satisfies energy conservation and mass conservation in the running process of the transformer, namely in a dynamic resistance balance state.
The gradient calculation module is used for calculating the average temperature gradient of the winding in the dynamic resistance balance state.
When the oil immersed inductive power equipment is in the dynamic resistance balance state, calculating the average temperature gradient of the winding in the state. The module includes a first computing unit and a second computing unit.
The first calculation unit is used for calculating a winding convection heat exchange coefficient by adopting a corrected Seider-Tate formula:
in the formula (8), nu is Knoop number, re is Reynolds number, pr is Plantt number, d is hydraulic diameter, unit m, L is characteristic length, unit m, mu is viscosity coefficient, unit m 2 And/s. The subscript f represents an insulating liquid and the subscript w represents a winding.
The convective heat transfer coefficient of the winding with the insulating liquid can be expressed as:
in the formula (9), h represents a convection heat transfer coefficient, and the unit is W/(m) 2 K), lambda is the thermal conductivity of the insulating liquid in W/(m.K).
The second calculating unit is used for calculating the average temperature gradient of the winding under the condition that the heat convection coefficient of the winding is obtained, and the specific process is as follows:
according to the winding geometry, calculating the surface area of the winding in contact with oil, namely the heat exchange area, and obtaining the average surface heat flow density of the winding so as to obtain the average temperature gradient of the insulating liquid in the winding and the insulating cylinder
In the formula (10), deltaθ AB The unit is K, which is the average temperature difference between the winding and the insulating liquid in the insulating cylinder.
According to the definition of GB1094.2-2013, the average temperature gradient of windings of a liquid-immersed transformer and a reactor is the difference between the average temperature of the windings and the average temperature of insulating liquid, namely the average temperature difference between the windings and the insulating liquid in an insulating cylinder plus the average temperature difference between the insulating liquid inside and outside the insulating cylinder:
Δθ＝Δθ AB +0.5*(Δt AB -Δt A′B′ )*ξ (11)
in the formula (11), delta theta is the average temperature gradient of the winding, and the unit is K; θ m The unit is K for the average temperature rise of the insulating liquid; ζ is a coefficient dependent on the winding position.
From the technical scheme, the application provides a device for determining the average temperature gradient of a winding, which is applied to electronic equipment, in particular to a heat exchange process loop model for constructing internal heat exchange of oil immersed inductive power equipment; constructing a flow power calculation model of oil flow in the oil immersed inductive power equipment according to the heat exchange process loop model; constructing a flow resistance calculation model of the oil flow according to the heat exchange process loop model; performing iterative computation on the flow power computing model and the flow resistance computing model to obtain current flow power and current flow resistance, and determining that the oil immersed inductive power equipment is in a dynamic resistance balance state when the error of the current flow power and the current flow resistance is smaller than a preset error threshold value; and calculating the average temperature gradient of the windings of the oil immersed inductive power equipment in the dynamic resistance balance state. The heat exchange coefficient with the experience coefficient property is not needed in the processing scheme, and objectivity is high, so that the winding average temperature gradient with high accuracy can be obtained, and the reliability and the economy of the design of the inductive power equipment are improved.
Example III
The embodiment provides an electronic device with data computing and information processing capabilities, such as a server or a computer, and the like, which is provided with the device for determining the average temperature gradient of the winding, provided by the embodiment, and the device is particularly used for constructing a heat exchange process loop model of internal heat exchange of the oil-immersed inductive power device; constructing a flow power calculation model of oil flow in the oil immersed inductive power equipment according to the heat exchange process loop model; constructing a flow resistance calculation model of the oil flow according to the heat exchange process loop model; performing iterative computation on the flow power computing model and the flow resistance computing model to obtain current flow power and current flow resistance, and determining that the oil immersed inductive power equipment is in a dynamic resistance balance state when the error of the current flow power and the current flow resistance is smaller than a preset error threshold value; and calculating the average temperature gradient of the windings of the oil immersed inductive power equipment in the dynamic resistance balance state. The heat exchange coefficient with the experience coefficient property is not needed in the processing scheme, and objectivity is high, so that the winding average temperature gradient with high accuracy can be obtained, and the reliability and the economy of the design of the inductive power equipment are improved.
Example IV
Fig. 5 is a block diagram of an electronic device according to an embodiment of the present application.
As shown in fig. 5, the electronic device provided in this embodiment has data computing and information processing capabilities, such as a server or a computer, and includes at least one processor 101 and a memory 102, which are connected by a data bus 103. The memory is used for storing a computer program or instructions, and the processor is used for acquiring and executing the corresponding computer program or instructions, so that the electronic device realizes the method for determining the average temperature gradient of the winding provided in the first embodiment.
The method for determining the average temperature gradient of the winding comprises the steps of constructing a heat exchange process loop model of internal heat exchange of oil immersed inductive power equipment; constructing a flow power calculation model of oil flow in the oil immersed inductive power equipment according to the heat exchange process loop model; constructing a flow resistance calculation model of the oil flow according to the heat exchange process loop model; performing iterative computation on the flow power computing model and the flow resistance computing model to obtain current flow power and current flow resistance, and determining that the oil immersed inductive power equipment is in a dynamic resistance balance state when the error of the current flow power and the current flow resistance is smaller than a preset error threshold value; and calculating the average temperature gradient of the windings of the oil immersed inductive power equipment in the dynamic resistance balance state. The heat exchange coefficient with the experience coefficient property is not needed in the processing scheme, and objectivity is high, so that the winding average temperature gradient with high accuracy can be obtained, and the reliability and the economy of the design of the inductive power equipment are improved.
In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described by differences from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other.
It will be apparent to those skilled in the art that embodiments of the present application may be provided as a method, apparatus, or computer program product. Accordingly, embodiments of the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the application may take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
Embodiments of the present application are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the embodiments of the application.
Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or terminal device comprising the element.
The foregoing has outlined rather broadly the more detailed description of the application in order that the detailed description of the application that follows may be better understood, and in order that the present principles and embodiments may be better understood; 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 application, the present description should not be construed as limiting the present application in view of the above.
Claims (6)
1. A method of determining a winding average temperature gradient for an electronic device having data computing and information processing capabilities, the method comprising the steps of:
constructing a heat exchange process loop model of internal heat exchange of the oil immersed inductive power equipment;
constructing a flow power calculation model of oil flow in the oil immersed inductive power equipment according to the heat exchange process loop model;
constructing a flow resistance calculation model of the oil flow according to the heat exchange process loop model;
performing iterative computation on the flow power calculation model and the flow resistance calculation model to obtain current flow power and current flow resistance, and determining that the oil immersed inductive power equipment is in a dynamic resistance balance state when the error between the current flow power and the current flow resistance is smaller than a preset error threshold value;
calculating the average temperature gradient of windings of the oil-immersed inductive power equipment in the dynamic resistance balance state;
the construction of a flow power calculation model of the oil flow in the oil immersed inductive power equipment according to the heat exchange process loop model comprises the following steps:
establishing the specific gravity-temperature differential of insulating liquid which participates in heat exchange in the winding from the angle of generating buoyancy from the liquid density change according to the Boussinesq principle, and integrating a process loop to obtain the flow power calculation model;
the construction of the flow resistance calculation model of the oil flow according to the heat exchange loop model comprises the following steps:
acquiring winding geometric parameters of the oil immersed inductive power equipment, carrying out equivalent treatment on the characteristic dimensions of the oil ducts participating in heat exchange in the windings according to the winding geometric parameters and applying a similar principle, and constructing the flow resistance calculation model according to the equivalent dimensions;
the step of calculating the average temperature gradient of the windings of the oil immersed inductive power device in the dynamic resistance balance state comprises the following steps:
calculating a convective heat transfer coefficient between a winding of the oil immersed inductive power device and insulating oil;
and calculating the average temperature gradient of the winding according to the convection heat transfer coefficient.
2. The determination method of claim 1, wherein the oil-immersed inductive power device is divided into an external heat exchange and the internal heat exchange with a tank wall as a boundary.
3. A device for determining a winding average temperature gradient for use in an electronic device having data computing and information processing capabilities, the device comprising:
the first construction module is configured to construct a heat exchange process loop model of internal heat exchange of the oil immersed inductive power device;
the second construction module is configured to construct a flow power calculation model of the oil flow in the oil immersed inductive power device according to the heat exchange process loop model;
a third building module configured to build a flow resistance calculation model of the oil flow from the heat exchange process loop model;
the iterative computation module is configured to perform iterative computation on the flow power computation model and the flow resistance computation model to obtain current flow power and current flow resistance, and when the error between the current flow power and the current flow resistance is smaller than a preset error threshold value, the oil immersed inductive power equipment is determined to be in a dynamic resistance balance state;
a gradient calculation module configured to calculate a winding average temperature gradient of the oil-immersed inductive power device in the dynamic resistance balance state;
the second construction module is specifically configured to generate a floating force angle from the liquid density change according to a Boussinesq principle, establish the specific gravity-temperature differential of insulating liquid in the winding which participates in heat exchange, and perform process loop integration to obtain the flow power calculation model;
the third construction module is specifically configured to acquire winding geometric parameters of the oil immersed inductive power equipment, perform equivalent processing on characteristic dimensions of oil channels participating in heat exchange inside a winding according to the winding geometric parameters and by applying a similar principle, and construct the flow resistance calculation model according to the equivalent dimensions;
the gradient calculation module includes:
a first calculation unit configured to calculate a convective heat transfer coefficient between a winding of the oil-immersed inductive power device and insulating oil;
a second calculation unit configured to calculate the winding average temperature gradient from the convective heat transfer coefficient.
4. A determining device according to claim 3, wherein the oil-filled inductive power device is divided into an external heat exchange and the internal heat exchange, bounded by a tank wall.
5. An electronic device characterized in that a determination device of the winding average temperature gradient according to any one of claims 3 to 4 is provided.
6. An electronic device comprising at least one processor and a memory coupled to the processor, wherein:
the memory is used for storing a computer program or instructions;
the processor is configured to execute the computer program or instructions to cause the electronic device to implement the method for determining a winding average temperature gradient according to any one of claims 1-2.
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