Method for establishing simulation model of sealed box-type substation and method for designing flow channel

Abstract

The present invention provides a method for establishing a simulation model of a sealed box-type substation and a method for designing a flow channel, relating to the technical field of sealed box-type substations. The temperatures of each wall surface of the sealed box-type substation during operation are obtained, and wall boundaries are generated based on the obtained temperatures, and the wall boundaries are used as boundary conditions in the initial simulation model. A fan model is constructed according to the fan characteristics; heat sources are determined according to the respective electrical characteristics of the actual devices in the sealed box-type substation; a circuit breaker model is constructed based on the electrical characteristics of the circuit breaker and the connection relationships between the circuit breaker, the flexible connection, and the main busbar; in the initial simulation model loaded with the fan model and the circuit breaker model, the material parameters of the sealed box-type substation are set to form a simulation model of the sealed box-type substation. The present invention reasonably simplifies the simulation model, can accurately calculate the flow and heat transfer conditions inside the substation, relatively accurately simulates the temperature field and flow field inside the substation, and guides the design of the internal flow channel of the substation.

Description

Technical Field

[0001] The present invention relates to the technical field of sealed box-type substations, in particular to a method for establishing a simulation model of a sealed box-type substation and a method for designing a flow channel of a sealed box-type substation. Background Art

[0002] The heat exchange situation inside a sealed box-type substation is very complex, and it is of great significance to design the flow channel inside the sealed box-type substation. This sealed box-type substation is a small and compact substation, and its shape should be as small as possible, and the floor area should be as small as possible. However, this compact design will have an adverse impact on the heat dissipation of the substation.

[0003] Due to the large number of devices and complex structural design inside the sealed box-type substation, there is currently no simulation model of a sealed box-type substation that can accurately and simply simulate the temperature field and flow field inside the substation and guide the design of the flow channel inside the substation. This has brought great trouble to the design of the flow channel of the sealed box-type substation. Summary of the Invention

[0004] In view of the above problems, the present invention proposes a method for establishing a simulation model of a sealed box-type substation and a method for designing a flow channel of a sealed box-type substation.

[0005] An embodiment of the present invention provides a method for establishing a simulation model of a sealed box-type substation, the sealed box-type substation does not communicate with the external air, and the method for establishing a simulation model of the sealed box-type substation includes:

[0006] Obtain the temperature of each wall surface of the sealed box-type substation during operation, generate a wall boundary according to the obtained temperature, and use the wall boundary as the boundary condition in the initial simulation model, and the boundary condition characterizes the temperature situation of each wall surface of the sealed box-type substation during operation;

[0007] Construct a fan model according to the fan characteristics and load the fan model into the initial simulation model;

[0008] Determine the heat sources according to the electrical characteristics of the actual devices in the sealed box-type substation, and the heat sources include: circuit breakers, flexible connections, main busbars, branch busbars, auxiliary transformers, upper interfaces, and lower interfaces;

[0009] Based on the electrical characteristics of the circuit breaker and the connection relationship between the circuit breaker and the flexible connection and the main busbar, construct a circuit breaker model and load it into the initial simulation model;

[0010] In the initial simulation model loaded with the fan model and the circuit breaker model, set the material parameters of the sealed box-type substation to form the simulation model of the sealed box-type substation.

[0011] Optionally, obtain the temperatures of each wall surface of the sealed box-type substation during operation, and generate wall boundaries based on the obtained temperatures, including:

[0012] Obtain the temperatures of each wall surface of the sealed box-type substation under different environmental factors and different operation modes;

[0013] Generate corresponding temperature functions based on the multiple temperatures obtained under different environmental factors and different operation modes;

[0014] Generate the wall boundaries according to the temperature functions, and the temperature functions are used to solve the temperature distribution inside the sealed box-type substation under different environmental factors and different operation modes when accurately calculating the internal flow and heat transfer in the simulation model of the sealed box-type substation.

[0015] Optionally, the boundary conditions with the wall boundaries as the initial simulation model include: the boundary conditions of the low-voltage chamber wall, the boundary conditions of the high-voltage chamber wall, and the boundary conditions of the top and bottom of the box body;

[0016] Directly set preset boundary conditions for the adjacent walls of the low-voltage chamber transformer room and the adjacent walls of the high-voltage chamber transformer room.

[0017] Optionally, the fan characteristics include: fan structure, fan characteristic curve; constructing a fan model according to the fan characteristics, including:

[0018] Use a circular plane as the model of the fan blades in the fan structure;

[0019] Use a cylindrical protective cover as the model of the fan housing in the fan structure;

[0020] Set a corresponding pressure drop characteristic curve at the circular plane according to the fan characteristic curve to simulate the actual working condition of the fan;

[0021] Use the cylindrical protective cover to simulate the actual air inlet and outlet conditions of the fan.

[0022] Optionally, determine the heat source according to the electrical characteristics of the actual devices in the sealed box-type substation, including:

[0023] According to the power of each actual device, calculate the heat generation power of each actual device and the device connection during operation;

[0024] Select the actual device or heat generation location with the highest heat generation power to determine the heat source;

[0025] Wherein, the heat - generating position is a position in an actual device, or a connection point between two or more interconnected actual devices.

[0026] Optionally, the circuit breaker includes: a frame circuit breaker, a molded - case circuit breaker;

[0027] The material parameters of sealed - type box - type substations of different models are the same or different, including but not limited to: the material parameters of the main busbar, the flexible connection, the circuit breaker, the branch busbar, the upper interface, and the lower interface are copper;

[0028] The material parameters of the walls of the low - voltage cabinets in the low - voltage chamber and the walls between the low - voltage chamber and the high - voltage chamber are stainless steel;

[0029] The material parameters of the partition board, the insulating board, the housing of the frame circuit breaker, and the counter are plastic;

[0030] The material parameter of the fixing plate of the molded - case circuit breaker is iron.

[0031] An embodiment of the present invention provides a flow - channel design method. The flow - channel design method is designed based on the above - mentioned sealed - type box - type substation simulation model to obtain the heat - dissipation flow channels inside the sealed - type box - type substation. The flow - channel design method includes:

[0032] According to the position of the heat source and in combination with the temperature conditions, determine the air - flow path inside the sealed - type box - type substation;

[0033] According to the air - flow path and in combination with the position of the heat source, determine the initial number of fans and their installation positions;

[0034] According to the air - flow path, determine the initial installation positions of the air ducts, and the opening positions of the walls between the low - voltage chamber and the high - voltage chamber and the low - voltage cabinets in the low - voltage chamber;

[0035] Based on the air - flow path, in combination with the initial number of fans and their installation positions, the initial installation positions of the air ducts, and the opening positions of the walls between the low - voltage chamber and the high - voltage chamber, obtain the initial flow channels. Then, in combination with the material parameters of the sealed - type box - type substation, use the sealed - type box - type substation simulation model to simulate the temperature field and flow field inside the sealed - type box - type substation to obtain the heat - dissipation efficiency of the initial flow channels;

[0036] On the basis of the initial flow channels, continuously adjust one or more of the number of fans and their installation positions, the initial installation positions of the air ducts, and the opening positions of the walls between the low - voltage chamber and the high - voltage chamber. Each time an adjustment is made, a new flow channel is obtained and its corresponding heat - dissipation efficiency is obtained. Repeat this process until the heat - dissipation efficiency reaches the optimum to obtain the heat - dissipation flow channels.

[0037] Optionally, the temperature condition includes that the temperature of the low-voltage chamber is higher than that of the high-voltage chamber.

[0038] Based on the position of the heat source and in combination with the temperature condition, determine the air flow path inside the sealed box-type substation, including:

[0039] Based on the simulation model of the sealed box-type substation, simulate the temperature field and flow field inside the substation, and numerically simulate the temperature field and flow field of the simulation model of the sealed box-type substation by using the computational fluid dynamics method to simulate the temperature field and flow field inside the sealed box-type substation.

[0040] Based on the simulated temperature field and flow field, and in combination with the condition that the temperature of the low-voltage chamber is higher than that of the high-voltage chamber, determine the air flow path as: flowing from the lower part of the low-voltage chamber to the upper part of the low-voltage chamber, from the upper part of the low-voltage chamber to the upper part of the high-voltage chamber, then from the upper part of the high-voltage chamber to the lower part of the high-voltage chamber, and finally from the lower part of the high-voltage chamber to the lower part of the low-voltage chamber.

[0041] Optionally, the position of the heat source includes: the connection position between the circuit breaker and the flexible connection, and the connection position between the circuit breaker and the main busbar.

[0042] The number and installation position of the fans in the heat dissipation flow path include:

[0043] Install one fan at the side wall position of the low-voltage cabinet that is flush with the connection position between the circuit breaker and the flexible connection.

[0044] Set the rear panel of the low-voltage cabinet below the main busbar and install one fan below the rear panel of the low-voltage cabinet.

[0045] Install one fan at the opening position where the air duct is connected to the walls of the low-voltage chamber and the high-voltage chamber.

[0046] Optionally, the installation position of the air duct in the heat dissipation flow path, as well as the initial opening positions of the walls of the low-voltage chamber and the high-voltage chamber and the low-voltage cabinet in the low-voltage chamber include:

[0047] The air duct is installed in the upper part of the low-voltage chamber and the upper part of the high-voltage chamber.

[0048] Open holes in the middle and lower parts of the walls of the low-voltage chamber and the high-voltage chamber, and open holes in the lower part of the low-voltage cabinet.

[0049] The method for establishing the simulation model of the sealed box-type substation provided by the present invention first obtains the temperatures of each wall surface of the sealed box-type substation during operation, generates wall boundaries according to the obtained temperatures, and uses the wall boundaries as boundary conditions in the initial simulation model.

[0050] Next, a fan model is constructed based on the fan characteristics and loaded into the initial simulation model; heat sources are determined according to the electrical characteristics of the actual devices in the sealed type box-type substation; based on the electrical characteristics of the circuit breaker and the connection relationships between the circuit breaker, flexible connections, and main busbars, a circuit breaker model is constructed and loaded into the initial simulation model; finally, in the initial simulation model loaded with the fan model and the circuit breaker model, the material parameters of the sealed type box-type substation are set to form a sealed type box-type substation simulation model.

[0051] The method for establishing the sealed type box-type substation simulation model proposed in the present invention reasonably simplifies the simulation model based on the various characteristics and material characteristics of the substation structure and its devices. However, the simplified simulation model can also accurately calculate the flow and heat transfer conditions inside the substation. It can more accurately simulate the temperature field and flow field inside the substation and guide the design of the internal flow channels. The method for establishing the simulation model proposed in the present invention is not only applicable to this type of substation but also to other types of substations. The proposed design scheme for the heat dissipation flow channel to form a full circulation of the internal air is also applicable to the flow channel design of other substations, with high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0053] Figure 1 is a flowchart of a method for establishing a sealed type box-type substation simulation model according to an embodiment of the present invention;

[0054] Figure 2 is a schematic diagram of the fan model in an embodiment of the present invention;

[0055] Figure 3 is a schematic diagram of the model for calculating the busbar power according to electromagnetic simulation in an embodiment of the present invention;

[0056] Figure 4 is a simplified schematic diagram of the model of the branch current inlet viewed from the bottom to the top of the box body in an embodiment of the present invention;

[0057] Figure 5 is a schematic diagram of the frame circuit breaker in an embodiment of the present invention;

[0058] Figure 6 is a three-dimensional schematic diagram of an exemplary sealed type box-type substation simulation model that has been established and whose internal heat dissipation flow channel has been designed in an embodiment of the present invention;

[0059] Figure 7This is the front view of the established simulation model of the sealed box-type substation corresponding to the embodiment of the present invention. Figure 6 The established simulation model of the sealed box-type substation corresponding to the embodiment of the present invention. Detailed implementation manners

[0060] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners. It should be understood that the specific embodiments described herein are only used to explain the present invention, which are only a part of the embodiments of the present invention, rather than all the embodiments, and are not used to limit the present invention.

[0061] The inventors found that currently, sealed box-type substations are generally divided into two categories. One type of sealed box-type substation does not circulate with the external air, that is, only the internal air of this type of sealed box-type substation flows, and there is no connection with the outside. Its sealing performance is very high. When it is in the outdoor environment for a long time, outdoor sand and dust will not enter the substation through some gaps, and it will not affect the normal operation of the substation. However, when this type of sealed box-type substation is operating, the heat inside it may be very high, causing the internal components to heat up and deform. In severe cases, it will damage the internal components and even cause a fire.

[0062] Another type of sealed box-type substation, strictly speaking, cannot be called a sealed box-type substation. It will install fans in the high-voltage room and the low-voltage room respectively, and use the fans to suck in the cooler air from the outside to cool the inside of the sealed box-type substation, and discharge the higher-temperature air inside the sealed box-type substation to the outside. This type of sealed box-type substation has a good effect of reducing temperature, but there are still gaps for air circulation with the outside. When it is in the outdoor environment for a long time, outdoor sand and dust will enter the substation through some gaps (between the fan blades or between the fan and the opening), which will affect the normal operation of the substation.

[0063] For the existing heat dissipation channels designed for the first type of sealed box-type substation that does not have air circulation with the outside, due to the large number of components and complex structure design inside the sealed box-type substation, the computational workload for designing the channels using its corresponding model is extremely large. For example, when designing the channels for the model corresponding to a certain small sealed box-type substation, it is necessary to divide seventy or eighty million or even hundreds of millions of grids, and then numerically simulate the flow and heat transfer inside the substation. At this time, ordinary workstations do not have such a large amount of computing resources, and usually need to rely on supercomputers, which is time-consuming and laborious, and the calculation cost surges.

[0064] Therefore, there is currently no simulation model of a sealed box-type substation that can accurately and simply simulate the temperature field and flow field inside the substation and guide the design of the internal flow channels of the substation, which brings great troubles to the flow channel design of the sealed box-type substation.

[0065] In view of the above problems, through a large amount of research and testing, the inventor creatively proposed a method for establishing a simulation model of a sealed box-type substation and a method for designing the flow channel of a sealed box-type substation of the present invention. The technical solutions of the present invention will be explained and described in detail below.

[0066] The sealed box-type substation proposed by the present invention is a substation that does not circulate with the external air and has no gaps with the outside world. The method for establishing the simulation model of the proposed sealed box-type substation refers to Figure 1 the flowchart of the method shown, and the method for establishing the simulation model of the sealed box-type substation includes:

[0067] Step 101: Obtain the temperatures of each wall surface of the sealed box-type substation during operation, generate a wall boundary according to the obtained temperatures, and use the wall boundary as the boundary condition in the initial simulation model. The boundary condition characterizes the temperature conditions of each wall surface of the sealed box-type substation during operation.

[0068] Since the model structure of the sealed box-type substation is complex, it is necessary to consider how to reasonably simplify the simulation model, but it is also necessary to ensure that the simplified simulation model can accurately calculate the flow and heat transfer inside the substation. When calculating the simulation model, in order to save computing resources, only the air flow inside the sealed box-type substation is simulated. Therefore, when establishing the simulation model, reasonable boundary conditions need to be given to the wall surface of the substation box.

[0069] Based on the above considerations, it is necessary to obtain the temperatures of each wall surface of the sealed box-type substation during operation, generate a wall boundary according to the obtained temperatures, and use the wall boundary as the boundary condition in the initial simulation model. The boundary condition characterizes the temperature conditions of each wall surface of the sealed box-type substation during operation.

[0070] A preferred method for obtaining the temperatures of each wall surface of the sealed box-type substation during operation and generating a wall boundary according to the obtained temperatures includes:

[0071] Step S1: First, obtain the temperatures of each wall surface of the sealed box-type substation under different environmental factors and different operating modes. For example: it can be under various weather conditions such as wind, frost, rain, and snow, in different temperature regions (including normal environmental temperatures and various extreme temperatures, such as: environmental temperature -10 to 40 degrees Celsius, extreme temperature -10 to -40 degrees Celsius or 40 to 60 degrees Celsius, etc.). In different operating modes, such as: no-load operation, full-load operation, 50% load operation, light-load operation, heavy-load operation, overload operation, etc. Under the above different environmental factors and different operating modes, use various measuring instruments, such as infrared imagers, etc. to collect and obtain the temperatures of each wall surface of the sealed box-type substation.

[0072] Step S2: Generate corresponding temperature functions based on multiple temperatures obtained under different environmental factors and different operating modes. Actually, multiple groups of temperature functions are generated, and each group of temperature functions corresponds to a working condition (a generalization of environmental factors and operating modes). In practical applications, the corresponding temperature function can be selected according to the specific working condition to be simulated, so as to obtain the corresponding temperature boundary conditions.

[0073] Step S3: Generate the wall boundary according to the temperature function. When the temperature function is used to accurately calculate the internal flow and heat transfer in the sealed box-type substation simulation model, it is used to solve the temperature distribution inside the sealed box-type substation under different environmental factors and different operating modes.

[0074] After obtaining each temperature in Step S1, temperature functions are generated based on these temperatures and their corresponding environmental factors and operating modes. When this temperature function is applied to the sealed box-type substation simulation model to accurately calculate the internal flow and heat transfer, it is used to solve the temperature distribution inside the sealed box-type substation under different environmental factors and different operating modes. For example: The generated temperature function can be written into a corresponding wall temperature program, and then the wall temperature program is loaded into the sealed box-type substation simulation model to solve the temperature distribution inside the sealed box-type substation under different environmental factors and different operating modes.

[0075] Preferably, using the wall boundary as the boundary condition in the initial simulation model includes: the boundary conditions of the low-voltage chamber wall, the boundary conditions of the high-voltage chamber wall, and the boundary conditions of the top and bottom of the box body. When simplifying the model, the transformer chamber does not need to be considered, and the corresponding temperature boundary conditions are given to the adjacent walls between the low-voltage chamber and the transformer chamber and the adjacent walls between the high-voltage chamber and the transformer chamber. Therefore, the preset boundary conditions are directly given to the adjacent walls between the low-voltage chamber and the transformer chamber and the adjacent walls between the high-voltage chamber and the transformer chamber. In this way, it is only necessary to divide the grid inside the low-voltage chamber and the high-voltage chamber, rather than dividing a huge amount of grids outside the entire simulation model, which greatly reduces the amount of calculation.

[0076] Step 102: Construct a fan model according to the fan characteristics and load the fan model into the initial simulation model.

[0077] In addition to the wall boundary, based on the characteristics of the sealed box-type substation: the temperature of its low-voltage chamber is higher than that of the high-voltage chamber. Therefore, if the air with a lower temperature in the high-voltage chamber is forced to flow to the low-voltage chamber, such a cycle can reduce the temperature of the low-voltage chamber, and further reduce the temperature at the highest position in the low-voltage chamber where the temperature is higher.

[0078] Based on this consideration, for forced air circulation, a fan is used. In the corresponding simulation model of a sealed box-type substation, a corresponding fan model needs to be constructed according to the fan characteristics and loaded into the initial simulation model.

[0079] Multiple fans can be installed inside the sealed box-type substation to cool the core components. Considering how to simplify the fan model, since the fan characteristics include: fan structure and fan characteristic curve. The fan structure refers to the actual structure of the fan, which generally has at least a fan blade and an external protective cover (usually cylindrical). And the fan also has its fan characteristic curve during actual operation, which reflects its working state during actual operation.

[0080] Based on the above considerations, when simplifying the fan model, a circular plane is used as the model of the fan blade in the fan structure; a cylindrical protective cover is used as the model of the fan housing in the fan structure. Refer to Figure 2 the schematic diagram of the fan model shown. It includes: a fan plane 1 and a protective cover 2. At the circular plane 1 (i.e., the fan plane 1), a corresponding pressure drop characteristic curve is set according to the fan characteristic curve to simulate the actual working condition of the fan; the cylindrical protective cover 2 is used to simulate the actual air inlet and outlet condition of the fan.

[0081] Step 103: Determine the heat sources according to the electrical characteristics of the actual components in the sealed box-type substation. The heat sources include: circuit breakers, flexible connections, main busbars, branch busbars, auxiliary transformers, upper interfaces, and lower interfaces.

[0082] After the wall boundary conditions and the fan model are completed, it is necessary to simplify the models of each component inside the substation. Since the temperature inside the substation mainly rises due to the operation of its components, it is necessary to determine the heat sources according to the electrical characteristics of the actual components in the sealed box-type substation.

[0083] A better way to determine the heat sources is: first, calculate the heat generation power of each actual component during operation according to their respective powers; select the actual component with the highest heat generation power or the heat generation location to determine the heat source. Among them, the so-called heat generation location is a certain location in the actual component, or the connection point between two or more interconnected actual components.

[0084] For example, in a sealed box-type substation, there are many components inside and the connections are complex. They include, but are not limited to: circuit breakers, flexible connections, branch busbars, main busbars, capacitors, resistors, voltage transformers, current transformers, cables, switches, relays, auxiliary transformers, upper interfaces, lower interfaces, etc. According to the respective powers of these devices, the heat generation powers of the devices and their connection points during operation can be calculated, sorted after obtaining the heat generation powers, and the actual device or heat generation location with the highest heat generation power can be selected to determine the heat source. The heat sources include: circuit breakers, flexible connections, main busbars, branch busbars, auxiliary transformers, upper interfaces, lower interfaces.

[0085] The purpose of obtaining the heat source is to restore the temperature field and flow field distribution inside the substation under actual conditions. The reasons for the heat generation of components such as branch busbars, main busbars, and flexible connections in the low-voltage compartment are as follows: current is conducted through them, ultimately causing the temperature on the busbars to rise. By setting the inlet of the branch current and using relevant electromagnetic calculation programs, the power distribution on each busbar can be obtained finally and loaded onto the main busbar, branch busbar, and upper interface. Refer to Figure 3 the schematic diagram of the model for calculating the busbar power based on electromagnetic simulation shown in Figure 3 which exemplarily shows two rows of branch current inlets corresponding to the branch busbar and upper interface, and one row of main current outlets corresponding to the main busbar.

[0086] It should be noted that in practice, each molded case circuit breaker (i.e., small circuit breaker) has three upper interfaces and three lower interfaces. Considering simplifying the model and saving computing resources, on the premise that it has little impact on the calculation results, refer to Figure 4 the simplified schematic diagram of the branch current inlet seen from the bottom to the top of the box shown in

[0087] Step 104: Based on the electrical characteristics of the circuit breaker and the connection relationship between the circuit breaker, flexible connection, and main busbar, construct a circuit breaker model and load it into the initial simulation model.

[0088] After obtaining the heat source as described above, it can be known that the devices that generate the most heat are: circuit breakers, flexible connections, and main busbars. When the sealed type box-type substation is in operation, the hottest places are located at the connections between the circuit breaker and the flexible connection, and between the circuit breaker and the main busbar. Whether the model established here is accurate is crucial. Therefore, based on the electrical characteristics of the circuit breaker and the connection relationships between the circuit breaker, the flexible connection, and the main busbar, a circuit breaker model is constructed and loaded into the initial simulation model.

[0089] When establishing the frame circuit breaker model, the plastic outer shell outside the frame circuit breaker needs to be considered. The shell material is plastic, while the material of the frame circuit breaker is mostly metal, and the thermal conductivity of plastic is much smaller than that of metal. The model establishment near the frame circuit breaker is relatively important, including the frame circuit breaker shell, frame circuit breaker, partition board, flexible connection, main busbar, current transformer, etc. To consider the temperature conditions at the connections between the frame circuit breaker and the flexible connection and between the frame circuit breaker and the main busbar, the contact surfaces are considered when simplifying the simulation model. The partition board and the current transformer will interfere with the air flow of the frame circuit breaker in the actual situation, so the influences of the partition board and the current transformer are considered.

[0090] Refer to Figure 5 the schematic diagram of the frame circuit breaker model shown in Figure 5 which exemplarily shows the structures and their mutual positional relationships of the frame circuit breaker, partition board, flexible connection, main busbar, and current transformer. The plastic outer shell model of the frame circuit breaker and the internal simplified model are exemplarily shown. The designs of the contact surfaces between the circuit breaker and the flexible connection and between the circuit breaker and the main busbar are for characterizing the different mesh divisions at these positions in the calculation because the temperature is the highest at these positions.

[0091] Step 105: In the initial simulation model loaded with the fan model and the circuit breaker model, set the material parameters of the sealed type box-type substation to form a sealed type box-type substation simulation model.

[0092] After the above simplification is completed, in the initial simulation model loaded with the fan model and the circuit breaker model, it is also necessary to set the material parameters of the sealed type box-type substation to form a sealed type box-type substation simulation model. This is because:

[0093] In actual numerical simulation calculations, it is necessary to reasonably consider the physical property parameters of the materials of each component. The material parameters of different models of sealed type box-type substations may be the same or different. For example: set the material parameters of the busbar, flexible connection, frame circuit breaker, molded case circuit breaker, branch busbar, auxiliary transformer, upper interface, and lower interface to copper; set the material parameters of the walls of the low-voltage cabinets in the low-voltage compartment and the walls between the low-voltage compartment and the high-voltage compartment to stainless steel; set the material parameters of the partition board, insulating board, frame circuit breaker shell, and counter to plastic; set the material parameter of the fixing plate of the molded case circuit breaker to iron, etc. The material parameters of different models of box-type substations are not necessarily the same, but this idea of establishing a simulation model is universal.

[0094] For a clearer understanding of the sealed box-type substation simulation model and its flow channel design proposed by the present invention, refer to Figure 6 the three-dimensional schematic diagram of an exemplary established sealed box-type substation simulation model shown in the figure, and its internal heat dissipation flow channel has been designed. Figure 7 corresponding to Figure 6 the front view of the established sealed box-type substation simulation model.

[0095] In an embodiment of the present invention, based on the above-mentioned method for establishing a sealed box-type substation simulation model, a method for designing the internal heat dissipation flow channel of the sealed box-type substation is proposed. Combining Figure 6 and Figure 7 , the flow channel design method includes:

[0096] Step T1: Determine the air flow path inside the sealed box-type substation according to the position of the heat source and in combination with the temperature conditions.

[0097] Since the temperature of the low-voltage chamber is higher than that of the high-voltage chamber, based on the sealed box-type substation simulation model, the temperature field and flow field inside the substation are simulated. The computational fluid dynamics method is used to numerically simulate the temperature field and flow field of the sealed box-type substation simulation model, and the temperature field and flow field inside the sealed box-type substation are simulated. Based on the simulated temperature field and flow field, and in combination with the fact that the temperature of the low-voltage chamber is higher than that of the high-voltage chamber, the determined air flow path is: flowing from the lower part of the low-voltage chamber to the upper part of the low-voltage chamber, from the upper part of the low-voltage chamber to the upper part of the high-voltage chamber, then from the upper part of the high-voltage chamber to the lower part of the high-voltage chamber, and finally from the lower part of the high-voltage chamber to the lower part of the low-voltage chamber.

[0098] Step T2: Determine the initial number of fans and their installation positions according to the air flow path and in combination with the position of the heat source.

[0099] According to the air flow path and in combination with the position of the heat source, determine the initial number of fans and their installation positions. For example Figure 6 、 Figure 7 exemplarily shows that the number of fans is 3 and the installation positions of the 3 fans are shown. The number of fans and their installation positions are the finally optimized determined positions, and the initial number of fans and their installation positions may not be at the Figure 6 、 7 positions.

[0100] Step T3: Determine the initial installation position of the air duct, as well as the initial opening positions on the walls of the low-voltage chamber and high-voltage chamber and the low-voltage switchgear in the low-voltage chamber according to the air flow path.

[0101] After the number of fans and their installation positions are determined, it is also necessary to determine the initial installation position of the air duct, as well as the initial opening positions on the walls of the low-voltage chamber and high-voltage chamber and the low-voltage switchgear in the low-voltage chamber according to the air flow path.

[0102] Step T4: Based on the air flow path, combined with the initial number and installation positions of the fans, the initial installation positions of the air ducts, and the opening positions of the walls of the low-voltage chamber and high-voltage chamber, obtain the initial flow path and combine with the material parameters of the sealed type substation. Use the sealed type substation simulation model to simulate the temperature field and flow field inside the sealed type substation, and obtain the heat dissipation efficiency of the initial flow path.

[0103] After determining the initial number and installation positions of the fans, the initial installation positions of the air ducts, and the opening positions of the walls of the low-voltage chamber and high-voltage chamber, it does not necessarily result in the optimal heat dissipation efficiency of the flow path. Therefore, combine the initial flow path with the material parameters of the sealed type substation, and then use the sealed type substation simulation model to simulate the temperature field and flow field inside the sealed type substation to obtain the heat dissipation efficiency corresponding to the initial flow path.

[0104] Step T5: Based on the initial flow path, continuously adjust one or more of the number and installation positions of the fans, the initial installation positions of the air ducts, and the opening positions of the walls of the low-voltage chamber and high-voltage chamber. Each time an adjustment is made, a new flow path is obtained and its corresponding heat dissipation efficiency is obtained. Repeat the process until the heat dissipation efficiency reaches the optimum, and obtain the heat dissipation flow path.

[0105] After obtaining the heat dissipation efficiency corresponding to the initial flow path, if it is not the optimum, then based on the initial flow path, continuously adjust one or more of the number and installation positions of the fans, the initial installation positions of the air ducts, and the opening positions of the walls of the low-voltage chamber and high-voltage chamber. Each time an adjustment is made, a new flow path is obtained and its corresponding heat dissipation efficiency is obtained. Repeat the process until the heat dissipation efficiency reaches the optimum, and obtain the optimum heat dissipation flow path.

[0106] Combine Figure 6 、 7 As shown, since the air flow path is: flowing from the lower part of the low-voltage chamber to the upper part of the low-voltage chamber, from the upper part of the low-voltage chamber to the upper part of the high-voltage chamber, then from the upper part of the high-voltage chamber to the lower part of the high-voltage chamber, and finally from the lower part of the high-voltage chamber to the lower part of the low-voltage chamber, and the places with the most serious heat generation and the highest temperature are the connection positions between the circuit breaker and the flexible connection and the connection positions between the circuit breaker and the main busbar. Therefore, the number and installation positions of the fans in the heat dissipation flow path include:

[0107] Install a fan at the side wall position of the low-voltage cabinet flush with the connection position between the circuit breaker and the flexible connection, that is Figure 6 、 Figure 7 the low-voltage cabinet side fan in, and its air flow direction is from the outside of the low-voltage cabinet to the inside of the low-voltage cabinet.

[0108] Set the rear panel of the low-voltage cabinet under the main busbar, and install a fan under the rear panel of the low-voltage cabinet. That is Figure 6 、 Figure 7The rear panel and the lower fan of the low-voltage cabinet, with the air flow direction from the lower part of the low-voltage cabinet to the upper part of the low-voltage cabinet. The function of the rear panel is to fix the air blown out by the lower fan of the low-voltage cabinet so that it can smoothly reach the soft connection and the main busbar, because the temperatures at these two places are the highest.

[0109] A fan is also installed at the opening position where the air duct is connected to the walls of the low-voltage chamber and the high-voltage chamber. Figure 6 、 Figure 7 The medium-low-high voltage wall fan is used to draw the relatively high temperature in the low-voltage chamber to the high-voltage chamber. The air duct is installed in the upper parts of the low-voltage chamber and the high-voltage chamber. In addition, openings need to be made in the middle and lower parts of the walls of the low-voltage chamber and the high-voltage chamber, as well as in the lower part of the low-voltage cabinet.

[0110] Through the above flow channel design, the temperature of the core components inside the low-voltage cabinet of the substation is reduced, enabling the full recycling of the air inside the sealed box-type substation. Through the low-voltage and high-voltage wall holes, the cooler air inside the high-voltage chamber flows into the low-voltage chamber; after the air flowing into the low-voltage chamber from the low-voltage and high-voltage wall holes enters the low-voltage chamber, it is divided into two parts. One part is sucked in by the side wall fan of the low-voltage cabinet to cool the soft connection, the main busbar, and the circuit breaker; the other part is sucked in by the lower fan of the low-voltage cabinet through the bottom air inlet hole of the low-voltage cabinet, and cold air is blown upward from the lower part of the low-voltage cabinet to cool the area near the soft connection and the main busbar.

[0111] After the air flowing through the circuit breaker, the soft connection, and the connection between the soft connection and the main busbar cools these components, it flows into the air duct. Through the air duct and under the action of the low-voltage and high-voltage wall fan, it flows into the upper part of the high-voltage chamber, smoothly bringing part of the heat from the low-voltage chamber into the high-voltage chamber to achieve heat exchange. During the process of these air flowing from the high place to the bottom of the high-voltage chamber, the temperature will gradually decrease (because the temperature of the high-voltage chamber is low and the temperature of the low-voltage chamber is high), thus forming an air cooling cycle inside the substation. Since hot air will rise, although there is not enough air to fully cool the components on the left side of the low-voltage cabinet, the hot air at its top will also enter the high-voltage chamber through the air duct, thereby reducing the temperature around these components.

[0112] To verify the effectiveness of the method for establishing the simulation model of the sealed box-type substation and the flow channel design proposed in the present invention, temperature tests and simulations are carried out for the temperatures before and after the improvement of the simulation model (that is, before and after the flow channel is established in the simulation model established in the present invention), and the high-temperature comparison results of the two are obtained:

[0113] The ambient temperature is set to 10 °C, and the relevant boundaries are also the boundary conditions measured at the ambient temperature of 10 °C. Before and after the improvement of the simulation model, the area with the highest temperature is near the soft connection and the main busbar close to the frame circuit breaker. The results obtained are:

[0114] Before the improvement of the simulation model, the highest temperature near the frame circuit breaker of the flexible connection and the main busbar was calculated to be 54.63 °C; after the improvement of the simulation model, the highest temperature of the flexible connection and the main busbar near the frame circuit breaker was 45.52 °C. It can be seen from this that the method for establishing the simulation model of the sealed box-type substation and the effectiveness of the flow channel design proposed in the present invention.

[0115] In addition, compared with the traditional simulation model of the sealed box-type substation, the number of grids used in the calculation of the simulation model of the sealed box-type substation proposed in the present invention has decreased significantly. When calculating the traditional simulation model of the sealed box-type substation, the number of grids used reached about 97 million, while the number of grids used in the calculation of the simulation model of the sealed box-type substation proposed in the present invention was reduced to about 12 million. However, the calculation results of the two are almost the same, which proves that the simplification of the simulation model of the sealed box-type substation proposed in the present invention is reasonable and effective compared with the traditional simulation model of the sealed box-type substation.

[0116] In summary, for the method for establishing the simulation model of the sealed box-type substation of the present invention, first, the temperatures of each wall surface of the sealed box-type substation during operation are obtained, the wall surface boundaries are generated according to the obtained temperatures, and the wall surface boundaries are used as the boundary conditions in the initial simulation model.

[0117] Then, a fan model is constructed according to the fan characteristics and loaded into the initial simulation model; heat sources are determined according to the electrical characteristics of the actual devices in the sealed box-type substation; based on the electrical characteristics of the circuit breaker and the connection relationship between the circuit breaker, the flexible connection, and the main busbar, a circuit breaker model is constructed and loaded into the initial simulation model; finally, in the initial simulation model loaded with the fan model and the circuit breaker model, the material parameters of the sealed box-type substation are set to form a simulation model of the sealed box-type substation.

[0118] The method for establishing the simulation model of the sealed box-type substation proposed in the present invention reasonably simplifies the simulation model based on the various characteristics of the substation structure and its devices and material characteristics. However, the simplified simulation model can also accurately calculate the flow and heat transfer conditions inside the substation. It can more accurately simulate the temperature field and flow field inside the substation and guide the internal flow channel design of the substation. The method for establishing the simulation model proposed in the present invention is not only applicable to this type of substation, but also applicable to other types of substations. The proposed design scheme for the heat dissipation flow channel to form a full circulation of the internal air is also applicable to the flow channel design of other substations, and has high practicability.

[0119] Although the preferred embodiments of the embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

[0120] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising said element.

[0121] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit and scope protected by the claims of the present invention. All of these are within the protection scope of the present invention.

Claims

1. A method for establishing a simulation model of a sealed box-type substation, characterized in that: The sealed box-type substation does not circulate with the outside air, and the method for establishing the simulation model of the sealed box-type substation includes: Acquire the temperature of each wall of the sealed box-type substation during operation, generate the wall boundary according to the acquired temperature, and use the wall boundary as the boundary condition in the initial simulation model, wherein the boundary condition represents the temperature of each wall of the sealed box-type substation during operation; Constructing a fan model according to the fan characteristics, and loading the fan model into the initial simulation model; Determine the heat source according to the electrical characteristics of each actual device in the sealed box-type substation, the heat source includes: circuit breaker, soft connection, main bus, branch bus, auxiliary transformer, upper interface, lower interface; Based on the electrical characteristics of the circuit breaker and the connection relationship between the circuit breaker and the soft connection and the main bus, a circuit breaker model is constructed and loaded into the initial simulation model; In the initial simulation model loaded with the wind turbine model and the circuit breaker model, material parameters of the sealed box-type substation are set to form a simulation model of the sealed box-type substation.

2. The method for establishing a simulation model of a sealed box-type substation according to claim 1, characterized in that: Obtain the temperature of each wall of the sealed box-type substation during operation, and generate the wall boundary according to the obtained temperature, including: Obtain the temperature of each wall of the sealed box-type substation under different environmental factors and different operating modes; Generate corresponding temperature functions according to multiple temperatures obtained under different environmental factors and different operating modes; The wall boundary is generated according to the temperature function. When the sealed box-type substation simulation model accurately calculates the internal flow and heat transfer conditions, the temperature function is used to solve the temperature distribution inside the sealed box-type substation under different environmental factors and different operating modes.

3. The method for establishing a simulation model of a sealed box-type substation according to claim 1, characterized in that: The boundary conditions in the initial simulation model using the wall boundary include: the boundary conditions of the low-pressure chamber wall, the boundary conditions of the high-pressure chamber wall, and the boundary conditions of the top and bottom of the box; The preset boundary conditions are directly given to the adjacent walls of the low-voltage room transformer room and the adjacent walls of the high-voltage room transformer room.

4. The method for establishing a simulation model of a sealed box-type substation according to claim 1, characterized in that: The fan characteristics include: fan structure, fan characteristic curve; constructing a fan model according to the fan characteristics includes: A circular plane is used as a model of a fan blade in the fan structure; A cylindrical protective cover is used as a model of a fan housing in the fan structure; Setting a corresponding pressure drop characteristic curve at the circular plane according to the fan characteristic curve to simulate the actual fan working condition; The cylindrical protective cover is used to simulate the actual wind inlet and outlet conditions of the fan.

5. The method for establishing a simulation model of a sealed box-type substation according to claim 1, characterized in that: The heat source is determined according to the electrical characteristics of the actual devices in the sealed box-type substation, including: According to the power of each of the actual devices, the heat generation power of each of the actual devices and the connection points of the devices during operation is calculated; Select the actual device or heating position with the highest heating power to determine the heat source; The heating position is a certain position in an actual device, or a connection point between two or more actual devices connected to each other.

6. The method for establishing a simulation model of a sealed box-type substation according to claim 1, characterized in that: The circuit breakers include: frame circuit breakers and molded case circuit breakers; The material parameters of sealed box-type substations of different models are the same or different, including: the material parameters of the main bus, the flexible connection, the circuit breaker, the branch bus, the upper interface, and the lower interface are copper; The material parameters of the low-voltage cabinet walls in the low-voltage room and the high-voltage room walls in the low-voltage room are stainless steel; The material parameters of the partition, the insulating plate, the housing of the frame circuit breaker, and the counter are plastic; The material parameter of the fixing plate of the molded case circuit breaker is iron.

7. A flow channel design method, characterized in that: The flow channel design method is designed based on the sealed box-type substation simulation model according to claim 1 to obtain the heat dissipation flow channel inside the sealed box-type substation. The flow channel design method includes: Determine the air flow path in the sealed box-type substation according to the location of the heat source and the temperature conditions; According to the air flow path and the location of the heat source, determine the initial number and installation location of the fans; According to the air flow path, determine the initial air duct installation position, as well as the initial opening positions of the low-pressure chamber and high-pressure chamber walls, and the low-pressure cabinet in the low-pressure chamber; Based on the air flow path, combined with the initial number and installation position of fans, the initial air duct installation position and the initial opening position of the low-pressure chamber and high-pressure chamber wall, the initial flow channel is obtained and combined with the material parameters of the sealed box-type substation, the sealed box-type substation simulation model is used to simulate the temperature field and flow field in the sealed box-type substation to obtain the heat dissipation efficiency of the initial flow channel; On the basis of the initial flow channel, one or more of the number and installation positions of fans, the initial air duct installation position, and the initial opening positions of the walls of the low-pressure chamber and the high-pressure chamber are continuously adjusted. Each time an adjustment is made, a new flow channel is obtained and its corresponding heat dissipation efficiency is obtained. This is repeated until the heat dissipation efficiency reaches the optimal level to obtain the heat dissipation flow channel.

8. The flow channel design method according to claim 7, characterized in that: The temperature conditions include: the temperature of the low-pressure chamber is higher than the temperature of the high-pressure chamber; According to the location of the heat source and the temperature conditions, the air flow path in the sealed box-type substation is determined, including: Based on the sealed box-type substation simulation model, the temperature field and flow field in the substation are simulated, and the temperature field and flow field in the sealed box-type substation simulation model are numerically simulated by using the computational fluid dynamics method to simulate the temperature field and flow field in the sealed box-type substation; Based on the simulated temperature field and flow field, and combined with the fact that the temperature of the low-pressure chamber is higher than that of the high-pressure chamber, the air flow path is determined as: flowing from the lower part of the low-pressure chamber to the upper part of the low-pressure chamber, from the upper part of the low-pressure chamber to the upper part of the high-pressure chamber, then from the upper part of the high-pressure chamber to the lower part of the high-pressure chamber, and finally from the lower part of the high-pressure chamber to the lower part of the low-pressure chamber.

9. The flow channel design method according to claim 8, characterized in that: The position of the heat source includes: the connection position of the circuit breaker and the soft connection, and the connection position of the circuit breaker and the main bus; The number and installation positions of fans in the heat dissipation channel include: A fan is installed at a position on the side wall of the low-voltage cabinet flush with the connection position of the circuit breaker and the flexible connection; A low-voltage cabinet rear plate is arranged below the main bus, and a fan is installed below the low-voltage cabinet rear plate; A fan is installed at the opening where the air duct connects to the wall of the low-pressure chamber and the high-pressure chamber.

10. The flow channel design method according to claim 8, characterized in that: The installation position of the air duct in the heat dissipation flow channel, as well as the initial opening positions of the low-pressure chamber and high-pressure chamber walls and the low-pressure cabinet in the low-pressure chamber include: The air duct is installed on the upper part of the low-pressure chamber and the upper part of the high-pressure chamber; A hole is opened in the middle and lower part of the wall of the low-voltage chamber and the high-voltage chamber, and a hole is opened in the lower part of the low-voltage cabinet.

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