Switch cabinet

Abstract

The invention relates to a switchgear cabinet having at least two juxtaposed unit cabinets, each unit cabinet comprising a plurality of compartments for accommodating electrical components, the switchgear cabinet comprising a vertically extending flow-reducing channel arranged on the end side in the side-by-side direction of the unit cabinets, the upper end of the flow-reducing channel being in communication with a top pressure-releasing and current-collecting channel of the switchgear cabinet, and the lower end of the flow-reducing channel being in communication with a top pressure-releasing and current-collecting channel of the switchgear cabinet. The switch cabinet further comprises a flow supply pipe which extends along the side-by-side direction of the unit cabinets and sequentially penetrates through the interiors of the unit cabinets, the pipe section, located in each unit cabinet, of the flow supply pipe is provided with a shunting opening, and the shunting opening is in fluid communication with a predetermined compartment provided with a heating electrical element. The predetermined compartment provides an up-flow channel which extends from bottom to top and is communicated with the pressure relief and flow collection channel, an end side opening of the flow supply pipe is communicated with the adjacent down-flow channel, and an air self-circulation inner loop is formed by the pressure relief and flow collection channel, the down-flow channel, the flow supply pipe and the up-flow channel. According to the switch cabinet, the air state in the cabinet can be dynamically and automatically adjusted so as to prevent condensation and improve the temperature rise performance of the switch cabinet.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment, and particularly to a switch cabinet. Background Art

[0002] A switch cabinet refers to a complete set of distribution equipment assembled by arranging primary equipment (such as earthing switches, high-voltage circuit breakers, high-voltage contactors, main busbars, and branch busbar load switches, etc.) and secondary equipment (such as watt-hour meters, ammeters, voltmeters, wattmeters, power factor meters, frequency meters, etc.) for monitoring, controlling, measuring, adjusting, and protecting the primary equipment, and is used to control and protect circuits and equipment. Usually, the switch cabinet is in the form of juxtaposed cabinets, that is, assembled by multiple unit cabinets. The structures of the unit cabinets are generally similar. Each unit cabinet mainly includes a busbar chamber installed with main busbars and branch busbars, a circuit breaker chamber installed with a circuit breaker, a low-voltage chamber installed with control units such as relay protection, a cable chamber installed with components such as earthing switches, lightning arresters, current transformers, voltage transformers, and cables, etc.

[0003] Figures 1 to 6B The shown existing switch cabinet 1' includes 5 unit cabinets arranged side by side in a straight line. From the left end to the right end of the switch cabinet, there are arranged a first unit cabinet P1', a second unit cabinet P2', a third unit cabinet P3', a fourth unit cabinet P4', and a fifth unit cabinet P5' in sequence. Each unit cabinet is generally in the form of a box cabinet. The low-voltage chamber LVC', circuit breaker chamber CBC', busbar chamber BBC', and cable chamber CC' of each unit cabinet are separated by partitions. As Figures 5A - 5B and Figures 6A - 6B shown, the low-voltage chamber LVC' is located at the front corner of the top of the switch cabinet. The circuit breaker chamber CBC' is generally in an L shape surrounding the low-voltage chamber. The busbar chamber BBC' is located in the central area of the top of the switch cabinet near the circuit breaker chamber CBC'. The cable chamber CC' is generally in an L shape surrounding the busbar chamber BBC' and the lower part of the circuit breaker chamber CBC'. A pressure relief channel 12' is provided at the top of the switch cabinet 1'. The compartment layout structures of the unit cabinets in the switch cabinet are generally similar.

[0004] Figure 5A The three-dimensional schematic diagram of the third unit cabinet p3' located in the middle position in the shown existing switch cabinet 1' is shown. The main circuit equipment installed in this unit cabinet has a relatively large rated current (such as 2500 A). As Figures 1 - 2 and Figure 5A shown, a front ventilation slot SL1 is provided in the lower area of the front shell of the third unit cabinet, and this ventilation slot leads to the cable chamber. As Figure 3 and Figure 4 shown, a rear ventilation slot SL2 is provided at the lower position of the rear shell of the third unit cabinet. This rear ventilation slot is also communicated with the space in the cable chamber.

[0005] Figure 6A A three-dimensional schematic diagram of the existing first unit cabinet P1' in the switchgear cabinet is shown. The main circuit equipment installed in this first unit cabinet has a relatively small rated current (for example, 1250A). The rated current of the main circuit equipment installed in the second unit cabinet P2' and the fourth unit cabinet P4' is, for example, 625A. The fifth unit cabinet P5' is not loaded.

[0006] In Figure 1 In the existing switchgear cabinet 1' shown, only a part of the heat generated by the heating electrical components in the third unit cabinet located in the middle position of the switchgear cabinet is taken away by the air flow flowing through the front ventilation slots and the back ventilation slots. The heat dissipation effect is not good, and the air entering the unit cabinet may also cause the introduction of humid air, and the pollution is serious. During operation, it will also cause moisture absorption and condensation, resulting in an increase in surface leakage current and a corresponding decrease in insulation resistance. When the insulation drops to a certain level, local surface discharge will be caused.

[0007] The first unit cabinet P1' located at the left end is more vulnerable to the influence of the ambient temperature. For example, as the ambient temperature decreases, the air humidity in the cabinet will reach a certain proportion, and condensation will occur at a certain temperature, adhering to the surface of the electrical components for a long time, which is likely to corrode the electrical components and even cause accidents due to reasons such as creepage, short circuit, and breakdown, seriously threatening the safety of the power system. And the first unit cabinet P1' is not provided with ventilation slots and cannot achieve ventilation and heat dissipation. The temperature of the electrical components installed therein always remains at a high level, which will have a negative impact on the working performance of the components.

[0008] In addition, for a switchgear cabinet with multiple unit cabinets, once the switchgear cabinet is designed and completed, it means that the power distribution parameters and arrangement positions of each unit cabinet are fixed, while the external environment will change, such as the occurrence of extreme weather. Therefore, the normal use of the existing switchgear cabinet (including individual unit cabinets therein) is greatly limited, and the control and maintenance costs increase.

[0009] Especially for switchgear cabinets with a high protection level (such as IP5X or IP6X), the switchgear cabinet shell is almost completely enclosed, and the heat in the circuit breaker chamber cannot be discharged. The air temperature and humidity conditions in each area of the enclosed cabinet space cannot be accurately monitored. How to avoid condensation in a switchgear cabinet with a high protection level is also a quite thorny problem.

[0010] Therefore, the present invention aims to overcome one or more of the above problems. Summary of the Invention

[0011] In view of the above problems, the present invention provides an improved switchgear cabinet, which can dynamically prevent condensation from occurring without additional energy consumption and at the same time effectively dissipate heat from high-temperature electrical components, significantly extend the service life of the electrical components, and is beneficial to ensuring the safe and reliable operation of the switchgear cabinet.

[0012] According to one aspect of the present invention, there is provided a switchgear cabinet having at least two unit cabinets arranged side by side, each unit cabinet including a plurality of compartments for accommodating electrical components. The switchgear cabinet includes a pressure relief and current collecting channel located at the top. Characteristically, the switchgear cabinet includes a current descending channel provided at the end side in the side-by-side direction of the unit cabinets and extending vertically. The current descending channel communicates with the pressure relief and current collecting channel at its upper end. The switchgear cabinet further includes a current supply pipe extending in the side-by-side direction of the unit cabinets and successively passing through the interiors of the unit cabinets. The pipe segments of the current supply pipe located inside each unit cabinet are formed with diversion openings, and the diversion openings are in fluid communication with a predetermined compartment in which heat-generating electrical components are installed. The predetermined compartment provides an ascending channel extending from bottom to top and communicating with the pressure relief and current collecting channel. The end-side opening of the current supply pipe is in fluid communication with the adjacent current descending channel. Thus, an internal air self-circulation loop is formed in the switchgear cabinet by the pressure relief and current collecting channel, the current descending channel, the current supply pipe, and the ascending channel.

[0013] The switchgear cabinet according to the present invention can spontaneously perform internal air circulation in a dynamic manner to prevent condensation in low-temperature areas and at the same time effectively reduce the temperature of the electrical components that generate heat during operation.

[0014] Advantageously, the current supply pipe passes through the interiors of the unit cabinets in the bottom area of the switchgear cabinet. Thus, the air flow channels provided by the compartments are effectively utilized spatially, ensuring that the appearance of flow dead ends is avoided as much as possible.

[0015] Advantageously, the current supply pipe passing through the interiors of the unit cabinets includes a current supply pipe passing through the cable compartments for accommodating cables in each unit cabinet. Thus, the available space in the cable compartments can be used more advantageously.

[0016] Advantageously, the diversion openings formed on the current supply pipe passing through the cable compartments of each unit cabinet are in fluid communication with the cable compartments. The cable compartments in the unit cabinet have relatively long and narrow air flow channels, which are more conducive to the occurrence of the "chimney" effect.

[0017] Advantageously, the diversion openings formed on the current supply pipe passing through the cable compartments of each unit cabinet are in fluid communication with the breaker compartments for accommodating breakers. Thus, the temperature of the relatively high-temperature breakers can be significantly reduced without occupying the effective space of the breaker compartments.

[0018] Advantageously, the current supply pipe passing through the cable compartments of each unit cabinet includes a first current supply pipe and a second current supply pipe. The diversion openings on the first current supply pipe are in fluid communication with the cable compartments, and the diversion openings on the second current supply pipe are in fluid communication with the breaker compartments for accommodating breakers. Through this configuration, more air flow channels can be obtained by using the internal spaces of the cable compartments and the breaker compartments, making the temperature distribution in the space inside the cabinet as uniform as possible.

[0019] Advantageously, the current supply pipe passing through the interior of each unit cabinet includes a current supply pipe passing through the circuit breaker chamber for accommodating a circuit breaker in each unit cabinet. With this configuration, the temperature rise in the circuit breaker chamber can be significantly slowed down, which is more conducive to maintaining the normal operation of the circuit breaker in the circuit breaker chamber.

[0020] Advantageously, the loads of the main circuit equipment installed in at least two unit cabinets are different. Temperature gradients will be generated between different unit cabinets due to different loads, and the heat transfer between the unit cabinets generated thereby can also reduce the risk of condensation.

[0021] Advantageously, the number of unit cabinets is greater than or equal to 3, and the unit cabinet installed with the main circuit equipment having the highest rated current is generally arranged at the middle position when looking along the side-by-side direction of the unit cabinets of the switchgear cabinet. Thus, the gas flowing into the pressure relief and current collection channel in the middle unit cabinet can be shunted into the current reduction channels at both ends, thereby avoiding excessive air flow stagnation areas in the pressure relief and current collection channel.

[0022] Advantageously, the current reduction channel is defined by the side plate of the end unit cabinet of the switchgear cabinet and the cover-shaped end housing buckled on the side plate. Through the setting of the end housing, the current reduction channel, which is very crucial for the air self-circulation, can be obtained. Therefore, the device modification cost is low.

[0023] Advantageously, the switchgear cabinet includes a controller for anti-condensation monitoring, and a first sensor and a second sensor arranged in the current reduction channel and signal-connected to the controller. The first sensor is used to sense the temperature of the outer side wall of the current reduction channel, and the second sensor is used to sense the temperature and relative humidity of the air in the current reduction channel.

[0024] Advantageously, the switchgear cabinet further includes a dehumidification device arranged in the inner loop of the air self-circulation. The dehumidification device is signal-connected to the controller, and the controller controls the opening or deactivation of the dehumidification device according to the signals from the first sensor and the second sensor. Thus, the changes in the temperature and relative humidity of the air in the cabinet can be actively responded to, and further, it can be ensured with a greater safety factor that condensation will not occur during operation.

[0025] Advantageously, the protection level of the switchgear cabinet is IP5X or IP6X. The inner loop of the air self-circulation formed in the switchgear cabinet of the present invention is extremely beneficial to the switchgear cabinet housing with extremely high requirements for airtightness, because in the process of air circulation of the present invention, the heat dissipation problem of the heating electrical components is solved and the occurrence of condensation in the cabinet is avoided at the same time, without introducing external cooling air or setting additional power-consuming devices such as extra fans.

[0026] The switchgear according to the present invention, through the air self-circulation inner loop provided inside the cabinet, advantageously realizes the natural flow of air in each upflow channel of the loop by means of the chimney effect, reduces the gradient of the air thermal density (and temperature gradient) inside the cabinet, can dynamically self-adjust the air state inside the cabinet, reduces the risk of condensation, and at the same time effectively dissipates heat from electrical components with extremely high temperatures, obtaining a significant improvement in the thermal performance of the electrical components and increasing the service life of the electrical components. For a closed switchgear with extremely high dust-proof requirements, by means of the air self-circulation inner loop, the heat taken away from the compartment where the high-temperature electrical components are located is transferred to a lower-temperature part, such as the end-side cabinet wall, to reduce the risk of condensation, and at the same time, the temperature of the electrical components is reduced to prevent the electrical components from overheating. Advantageously, no additional fan device is required for the entire air circulation process, avoiding the problems of inconvenient maintenance and difficult control caused by the fan, and maintaining a suitable operating temperature of the electrical appliances inside the switchgear on the basis of energy conservation. In addition, by using the switchgear according to the present invention, local modification can be carried out on the basis of the existing single cabinet or combined cabinet, and the layout of the air self-circulation inner loop can be realized, and the modification process is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] With reference to the following detailed description and drawings, the features and advantages of an example of the present invention will become apparent, wherein:

[0028] Figure 1 A perspective schematic view of an existing switchgear as seen from the left front of the switchgear is shown;

[0029] Figure 2 Shown Figure 1 A perspective schematic view of the shown switchgear after removing the left end side plate is shown;

[0030] Figure 3 A perspective schematic view of an existing switchgear as seen from the right rear of the switchgear is shown;

[0031] Figure 4 Shown Figure 3 A perspective schematic view of the shown switchgear after removing the right end side plate is shown;

[0032] Figure 5A Shown Figure 1 A perspective schematic view of the third unit cabinet located in the middle position after removing the end side plate is shown;

[0033] Figure 5B Shown Figure 5A A cross-sectional view of the shown unit cabinet obtained along a vertical section is shown;

[0034] Figure 6A Shown Figure 1Schematic perspective view of the first unit cabinet in the first order position at the left end of the switchgear shown after removing the end side plates;

[0035] Figure 6B Shows Figure 6A Cross-sectional view of the unit cabinet shown obtained along a vertical section;

[0036] Figure 7 Schematic perspective view of the switchgear according to the present invention as seen from the front left of the switchgear;

[0037] Figure 8 Schematic perspective view of the switchgear according to the present invention as seen from the rear right of the switchgear;

[0038] Figure 9 Shows Figure 7 Schematic perspective view of the switchgear shown after removing the left end housing that defines the left side downflow channel;

[0039] Figure 10 Shows Figure 8 Schematic perspective view of the switchgear shown after removing the right end housing that defines the right side downflow channel;

[0040] Figure 11A Shows Figure 7 Schematic perspective view of the third unit cabinet in the middle position of the switchgear shown;

[0041] Figure 11B Shows Figure 11A Cross-sectional view of the switchgear shown obtained along a vertical section;

[0042] Figure 12A Shows Figure 7 Schematic perspective view of the first unit cabinet of the switchgear shown;

[0043] Figure 12B Shows Figure 12A Cross-sectional view of the switchgear shown obtained along a vertical section;

[0044] Figure 13 Schematic diagram of the pipe section of the first current supply pipe provided in the cable compartment of the switchgear according to the present invention;

[0045] Figure 14 Shows the internal air self-circulation loop formed in the switchgear according to the present invention;

[0046] Figure 15 Shows the air flow velocity distribution diagram in the internal air self-circulation loop in the switchgear according to the present invention; and

[0047] Figure 16 Shows the temperature distribution diagram of the electrical components in the switchgear according to the present invention; and

[0048] Figure 17 Shows a schematic layout diagram of sensors and a dehumidifying device in a switchgear cabinet according to the present invention. Detailed implementation manners

[0049] Hereinafter, specific embodiments of the present invention will be specifically referred to. Examples of the embodiments are shown in the drawings. As long as possible, the same reference numerals are used in all the drawings to represent the same or similar components.

[0050] As Figure 7 and Figure 8 shown, in terms of appearance, the switchgear cabinet 1 of the present invention can achieve overall enclosure compared with the existing switchgear cabinet 1', that is, there are no through holes, channels, slots, etc. communicating with the external environment in the outer shell of the switchgear cabinet. The switchgear cabinet of the present invention is particularly suitable for use as a switchgear cabinet with a protection level up to IP5X or IP6X.

[0051] Figure 7 and Figure 8 The switchgear cabinet 1 shown includes a first unit cabinet P1, a second unit cabinet P2, a third unit cabinet P3, a fourth unit cabinet P4, and a fifth unit cabinet P5. These unit cabinets are arranged side by side in a "one" shape. Each unit cabinet includes a low-voltage chamber LVC, a circuit breaker chamber CBC, a busbar chamber BBC, and a cable chamber CC. The rated current of the main circuit equipment installed in the third unit cabinet P3 is 2500A. The rated current of the main circuit equipment installed in the first unit cabinet P1 is 1250A. The rated current of the main circuit equipment installed in the second unit cabinet P2 and the fourth unit cabinet P4 is 625A. The fifth unit cabinet P5 is not loaded. The third unit cabinet P3 is located at approximately the middle position in the left-right direction of the switchgear cabinet. The layout orientations of the low-voltage chamber LVC, the circuit breaker chamber CBC, the busbar chamber BBC, and the cable chamber CC of each unit cabinet are basically the same. The low-voltage chamber LVC is located at the front upper corner of the switchgear cabinet. The circuit breaker chamber CBC generally surrounds the low-voltage chamber in an L shape. The busbar chamber BBC is located near the circuit breaker chamber in the central area at the top of the switchgear cabinet. The cable chamber CC generally surrounds the busbar chamber and the lower part of the circuit breaker chamber in an L shape. The upper parts of the circuit breaker chamber, the busbar chamber, and the cable chamber in the same unit cabinet are arranged side by side in the front-rear direction of the switchgear cabinet. The switchgear cabinet 1 includes a pressure relief and current collection channel 12 located at the top (see Figure 14 and Figure 17As shown, the pressure relief and collection channel 12 is defined by an arched hood-like member 120 and an orifice plate (not shown) disposed at the lower part of the hood-like member 120 and located at the top of the circuit breaker compartment, the busbar compartment, and the cable compartment. Orifices for communicating these compartments with the pressure relief and collection channel are formed in the orifice plate. The longitudinal extension direction of the hood-like member is consistent with the width direction of the switchgear cabinet (the side-by-side direction of the unit cabinets, i.e., the left-right direction). The pressure relief and collection channel 12 is in fluid communication with the circuit breaker compartments CBC, the busbar compartments BBC, and the cable compartments CC in all unit cabinets.

[0052] As Figure 9 and Figure 10 shown, the switchgear cabinet 1 according to the present invention includes a supply pipe 14 extending along the side-by-side direction of the unit cabinets and sequentially passing through the interiors of the respective unit cabinets. In the illustrated embodiment, the supply pipe 14 passes through the interiors of the respective unit cabinets in the bottom region (or a region near the bottom) of the switchgear cabinet. Advantageously, the compartments penetrated by the supply pipe are cable compartments. In the illustrated embodiment, the supply pipe passing through the cable compartments of the respective unit cabinets includes a first supply pipe 141 and a second supply pipe 142. The first supply pipe is located at the rear bottom corner position of the cable compartment. The diversion openings 1410 formed in the first supply pipe 141 (see Figure 9 , Figure 11A and Figure 12A shown) are in fluid communication with the cable compartment. The diversion openings 1420 formed in the second supply pipe 142 are aligned with the openings 150 formed in the partition plate defining the bottom wall of the circuit breaker compartment (see Figures 11A - 11B and Figures 12A - 12B shown), and thus are in fluid communication with the circuit breaker compartment.

[0053] See Figure 13 shown, the first supply pipe 141 is implemented as a plurality of pipe segments 141S having a generally rectangular cross-section that are sequentially butted. Butt flanges E are formed at the butting parts of the pipe segments, and openings (not shown) for passing the first supply pipe are formed at corresponding positions on the side plates of adjacent unit cabinets. When installing the first supply pipe, the butt flange E is abutted against the edge of the opening to achieve sealing between the outer edge of the first supply pipe and the side plate of the unit cabinet, and a sealing strip is provided between two butted butt flanges that abut against each other to achieve sealed connection between adjacent pipe segments. In the illustrated first supply pipe, the diversion openings 1410 are formed on the pipe wall facing the internal space of the cable compartment. Thus, as much air flow as possible enters the bottom region of the cable compartment, which is beneficial for making the air flow channel provided in the cable compartment CC in the vertical direction as long as possible.

[0054] Although Figure 13In the illustrated embodiment, the first supply pipe 141 located at the rear corner position at the bottom of the cable chamber has a rectangular cross-section and the second supply pipe 142 has a similar cross-sectional shape and configuration (the first supply pipe and the second supply pipe can be designed and manufactured based on the same dimensions, thereby reducing the design and manufacturing costs). It can be understood that the first supply pipe can also be placed at other positions in the cable chamber or configured to have a different cross-sectional shape. The second supply pipe can also be designed to have a cross-sectional shape different from the rectangular cross-section according to actual needs.

[0055] Combined Figure 7 with Figure 14 As shown, the switchgear 1 according to the present invention includes hood-shaped end housings 15 located on the left and right end sides of the switchgear. The end housings are buckled on the side plates 17 of the adjacent unit cabinets and are hermetically connected thereto. The end housings are made of metal and have good heat conduction performance. The end housings 15 and the side plates 17 of the adjacent unit cabinets jointly define a vertically extending flow-down channel 16. The flow-down channel 16 communicates with the pressure-relief collecting channel 12 at its top.

[0056] The two ends of the first supply pipe 141 are respectively in fluid communication with the flow-down channels 16 on the left and right end sides. The two ends of the second supply pipe 142 are respectively in fluid communication with the flow-down channels 16 on the left and right end sides.

[0057] Thus, inside the switchgear, the pressure-relief collecting channel 12 at the top, the flow-down channels 16 on the left and right end sides, the supply pipes 14 (including the first supply pipe 141 and the second supply pipe 142) passing through each unit cabinet, and the compartments (specifically, the up-flow channels 18 extending from bottom to top and communicating with the pressure-relief collecting channel provided by the compartments) in fluid communication with the diversion openings of the supply pipes jointly form an air self-circulation internal loop. This air self-circulation internal loop can utilize the heat dissipated from the electrical components to prevent the occurrence of condensation.

[0058] Next, the formation of the air self-circulation internal loop will be specifically described taking the first supply pipe as an example. Refer to Figure 14As shown, the cable chamber is configured to have an unobstructed flow space from the bottom to the top, and thus has an upward flow channel 18 similar to a "chimney passage". In the cable chamber, air flows through the heat-generating electrical components, and the heat dissipated from the heat-generating electrical components heats the surrounding air. Due to the density difference, the air quickly diffuses from bottom to top along the upward flow channel. The hot air overflows upward and flows into the pressure relief and current-collecting channel 12, and then flows into the end-side downward flow channel 16 through both ends of the pressure relief and current-collecting channel. The air flow in the end-side downward flow channel cools down due to heat transfer between the highly thermally conductive end housing and the lower-temperature external environment, and flows downward into the first air supply pipe 141. At the same time, since the upward overflowing hot air flow forms a low-pressure area in the bottom region of the cable chamber, this low pressure causes the air flow in the first air supply pipe to flow into the cable chamber. The air flow flowing into the cable chamber rises in temperature when heated by the heat-generating electrical components, and the hot air flows upward. In this way, the cycle repeats continuously, forming an internal air self-circulation loop.

[0059] The function of the second air supply pipe 142 is similar to that of the first air supply pipe 141. It can also utilize the upward flow channel extending from the bottom to the top in the circuit breaker chamber and the heat-generating characteristics of the circuit breaker to achieve the "chimney" effect, and utilize the good heat dissipation characteristics of the end-side downward flow channel to achieve the reflux supply of the air flow and the self-closure of the air flow cycle. That is, the air flowing into the circuit breaker chamber from the second air supply pipe 142 flows through the circuit breaker and is heated by the heat from the circuit breaker. The hot air flows upward along the upward flow channel from bottom to top, enters the pressure relief and current-collecting channel 12, and flows along the pressure relief and current-collecting channel into the end-side downward flow channel. Due to the good thermal conductivity of the end housing, efficient heat transfer occurs between the air in the downward flow channel and the external environment, so the temperature decreases. The cooled air flows into the second air supply pipe. At the same time, a low-pressure area is formed in the bottom region of the circuit breaker chamber due to the upward flow of hot air, and the air in the second air supply pipe is supplied to the low-pressure area and enters the circuit breaker chamber. Subsequently, the heated air flows upward again. In this way, the cycle repeats continuously, forming an internal air self-circulation loop.

[0060] The above internal air circulation is spontaneously generated due to the thermal density difference and there is no forced flow. During the circulation process, only the internal air circulates, and no air flowing in from the outside is introduced.

[0061] Through the formed internal air self-circulation loop, the heat from the heat-generating electrical components is advantageously carried to other parts of the switchgear (such as the end housing with a lower temperature), making the temperature distribution in the entire internal space of the switchgear tend to be uniform, preventing condensation from occurring on the end wall of the end housing while ensuring that the temperature of the heat-generating electrical components is maintained within a reasonable temperature range. In the case of a large temperature gradient, the air flow in the internal air self-circulation loop will automatically accelerate and then move in the direction of reducing the temperature gradient (or making the temperature distribution uniform).

[0062] As Figure 15 shown, at point V1 in the pressure relief and current collection channel, the air velocity is approximately 0.15 m / s; at point V2 in the circuit breaker chamber, the air velocity is approximately 0.57 m / s; and at point V3 at the diversion opening of the current supply pipe, the air velocity is approximately 0.28 m / s. From the shown air velocity distribution, the air flow velocity is relatively large around the heat-generating electrical components in the cable chamber / circuit breaker chamber. The air flow velocity in the diversion opening area of the current supply pipe is relatively large. Even in the section of the current supply pipe corresponding to the unit cabinet without loaded electrical components, there is also a relatively large air flow velocity. The air velocity distribution in the pressure relief and current collection channel is inconsistent: the air velocity is relatively large in the area near the end-side downflow channel and the area near the circuit breaker chamber in the pressure relief and current collection channel, while the air velocity significantly decreases in the area between these two areas. To accelerate the air flow in the pressure relief and current collection channel, as Figure 7 shown, the third unit with the largest rated current of the main circuit equipment is arranged in the middle position of the switchgear cabinet, which is beneficial to diverting the air flowing in from the upflow channel of the third unit to the downflow channels at both ends. Additionally, from Figure 15 it can also be seen that the higher the temperature area, the greater the air flow velocity, which can also be understood as being more beneficial for the heat dissipation of the heat-generating electrical components.

[0063] Under the ambient temperature of 30°C and certain load conditions, in the existing switchgear cabinet, the highest temperature point (generally located in the circuit breaker chamber) in the third unit cabinet where the main circuit equipment with a rated current of 2500 A is installed has a temperature rise of approximately 57 K relative to the ambient temperature, and the highest temperature point (generally located in the circuit breaker chamber) in the first unit cabinet at the end side where the main circuit equipment with a rated current of 1250 A is installed has a temperature rise of approximately 49 K relative to the ambient temperature. However, the temperature rise performance inside the switchgear cabinet of the present invention has been significantly improved compared with the existing switchgear cabinet. Referring to Figure 16 shown, when the switchgear cabinet of the present invention operates under the same load conditions and ambient temperature as the existing switchgear cabinet, the highest temperature point in the third unit cabinet ([[]] Figure 16 at the T1 position shown, also generally located in the circuit breaker chamber) where the main circuit equipment with a rated current of 2500 A is installed has a temperature rise of approximately 48 K relative to the ambient temperature, and the highest temperature point in the first unit cabinet ([[]] Figure 16 at the T2 position shown, also generally located in the circuit breaker chamber) at the end side where the main circuit equipment with a rated current of 1250 A is installed has a temperature rise of approximately 45 K relative to the ambient temperature. By comparison, it can be obtained that the switchgear cabinet according to the present invention can effectively inhibit the temperature rise inside the unit cabinet and has an improved heat dissipation effect on the heat-generating electrical components.

[0064] Therefore, the switchgear cabinet according to the present invention has strong dynamic self - regulating performance, effectively avoiding the problems of serious lag, high control difficulty and inaccurate control of the dew - proof mechanism provided in the existing switchgear cabinets. The switchgear cabinet according to the present invention thus has greatly reduced device cost, control cost and maintenance cost.

[0065] In addition, inevitably, there are more or less differences in the electrical component configuration between the unit cabinets of the switchgear cabinet (for example, the rated current of the main circuit equipment or the load of the main circuit equipment). The air self - circulation inner loop formed in the switchgear cabinet according to the present invention effectively reduces the thermal imbalance caused by the difference in the heat - generating power of the electrical components. When designing the layout position of the unit cabinets, there is no need to specially consider the difference in the heat - generating power of the main circuit equipment installed in each unit cabinet. Therefore, the design flexibility is increased. In addition, for the situation where it is necessary to modify or increase or decrease the load of the electrical components in the unit cabinet according to the actual situation, there are no constraints and limitations in any aspect (in contrast, the existing switchgear cabinets need to re - design the relevant unit cabinets, so the modification cost is high). Therefore, although Figure 7 shows that the third unit cabinet with a main circuit having a high rated current is arranged in the middle position and the unloaded unit cabinet is arranged at the side position, it can be understood that for the switchgear cabinet according to the present invention, the layout positions of these unit cabinets are not limited by the specific embodiments shown, because no matter what layout method is adopted, there is always an air self - circulation inner loop in the switchgear cabinet according to the present invention, and all temperature differences or temperature gradients occurring in the switchgear cabinet can be used to reduce the risk of dew formation.

[0066] Although Figures 9 to 12B shows that the switchgear cabinet is provided with a first supply pipe and a second supply pipe, it can be understood that the switchgear cabinet according to the present invention can also be provided with only one supply pipe. For example, in the case of only one first supply pipe being provided, the hot air in the circuit breaker chamber will escape into the pressure - relief and current - collecting channel, mix with the air flow entering the pressure - relief and current - collecting channel from the cable chamber, and the hot air in the circuit breaker chamber can also conduct heat transfer with the air in the cable chamber through the bottom or side partition of the circuit breaker chamber. Thus, the dynamic flow of the heat flow in the switchgear cabinet from the high - temperature area to the low - temperature area is indirectly realized. For the case of only one second supply pipe being provided, diversion openings can be added on the lower wall of the second supply pipe to realize the air circulation in the cable chamber. Therefore, the dynamic flow of the heat flow in the switchgear cabinet can also be realized, and the temperature gradient in the switchgear cabinet is utilized as much as possible to reduce the risk of dew formation.

[0067] Optionally or additionally, the switchgear cabinet can also be configured to include a supply pipe penetrating through the circuit breaker chamber of the unit cabinet. For a circuit breaker chamber with extremely high temperature rise, setting this type of supply pipe can advantageously take away the heat in the circuit breaker chamber and reduce the temperature of the circuit breaker.

[0068] Although Figures 7 to 10The switchgear cabinet shown in the figure is provided with current-reducing channels on both the left and right ends. It can be understood that according to the actual number of unit cabinets and space requirements, only one current-reducing channel can be provided on one end side of the switchgear cabinet (for example, the side facing the external low-temperature environment), and an internal air self-circulation loop for reducing the risk of condensation can still be formed by means of this current-reducing channel.

[0069] Although the switchgear cabinet of the present invention shown in the figure has 5 unit cabinets, it can be understood that the number of unit cabinets can be different from 5. For example, it can be any natural number greater than or equal to 2.

[0070] In this article, orientation terms such as "top", "upper part", "lower part", "left", "right", "front" and "rear" are the orientations pointed to when an operator describes the switchgear cabinet shown Figure 1 or Figure 7 the switchgear cabinet.

[0071] See Figure 17 As shown, to further monitor the temperature and humidity status of the air inside the cabinet to prevent condensation, the switchgear cabinet according to the present invention includes a controller (not shown) for anti-condensation monitoring, and a first sensor S1 and a second sensor S2 arranged in the current-reducing channel and signal-connected to the controller. The first sensor S1 is used to sense the temperature of the outer side wall of the current-reducing channel (i.e., the inner wall of the end housing 15). The second sensor S2 is used to sense the temperature and relative humidity of the gas in the current-reducing channel 16. To ensure the accuracy of the sensed values, the second sensor S2 is arranged on the inner side wall of the current-reducing channel (i.e., the plate wall opposite to the end housing). The switchgear cabinet 1 also includes a dehumidifying device 19 arranged in the internal air self-circulation loop, and the dehumidifying device 19 is signal-connected to the controller.

[0072] During the monitoring process, the controller calculates the water vapor density of the monitoring area based on the temperature value from the first sensor S1, the temperature value and relative humidity value from the second sensor S2, combined with the air pressure value, and calculates the dew point temperature of the current pressure based on the calculated water vapor density. If the temperature value measured by the first sensor is greater than the calculated dew point temperature by a certain amplitude (for example, 5°C), the controller determines that no condensation occurs. When the difference obtained by subtracting the calculated dew point temperature from the temperature value measured by the first sensor is less than, for example, 5°C (or the temperature value measured by the first sensor is lower than the calculated dew point temperature), the controller sends an opening signal to the dehumidifying device.

[0073] The dehumidification device uses chemical methods to absorb moisture and remove steam (such as using desiccants) to remove moisture in the air, or uses a condensation system to circulate and dehumidify to reduce the air humidity inside the switchgear cabinet. During the operation of the dehumidification device, when the temperature value measured by the first sensor is greater than the dew point temperature by a certain amplitude, the controller can send a stop signal to the dehumidification device. Therefore, the present invention can dynamically and real-time monitor condensation to ensure the safe and reliable operation of the switchgear cabinet.

[0074] Although the above description of the present invention is based on an enclosed switchgear cabinet (with a protection level up to IP5X or IP6X), it can be understood that the present invention can also be implemented in switchgear cabinets with a lower protection level (such as IP4X, IP3X, etc.), because in switchgear cabinets with a lower protection level, a small amount of air flowing into the cabinet from the outside does not affect the formation of the air circulation in the internal loop of the air self-circulation. That is to say, the purpose of the present invention can still be achieved, that is, moving the heat dissipated from the high-temperature area to the lower-temperature area to prevent condensation from occurring or reducing the risk of condensation.

[0075] Industrial Applicability

[0076] To facilitate the understanding of the present invention, the assembly process and working principle of the switchgear cabinet of the present invention will be described below:

[0077] See Figure 7 As shown, at least two unit cabinets are provided. Each unit cabinet can be a single cabinet in the form of a box cabinet. Corresponding pipe sections of the first supply pipe 141 and the second supply pipe 142 are installed at preset positions inside each unit cabinet. The unit cabinets are juxtaposed so that the pipe sections are aligned and docked in a sealed manner. A cover-like component is installed on the top of the switchgear cabinet to form a pressure relief and collection channel 12. The end housing 15 is covered on the side plate of the unit cabinet in the outermost position to form a downflow channel 16, and the downflow channel communicates with the pressure relief and collection channel at the upper part, and the end-side opening of the supply pipe communicates with the adjacent downflow channel. Thus, a closed loop is formed inside the switchgear cabinet by the pressure relief and collection channel, the downflow channel, the supply pipe, and the upflow channel 18 provided by the relevant compartments.

[0078] During the operation of the electrical components inside the switchgear cabinet, the electrical components dissipate heat and heat the surrounding air. According to the chimney effect, the hot air rises in the upflow channel and enters the pressure relief and collection channel, while the air in the side downflow channel dissipates heat to the outside through the end housing, the temperature decreases, and it flows downward and enters the supply pipe, and then flows into the low-pressure area formed by the rising of the hot air in the upflow channel. Due to the temperature gradient existing in the cabinet, air self-circulation is spontaneously generated, and thus the heat from the electrical components is guided to the vicinity of the inner wall of the end housing where condensation is particularly likely to occur, reducing the risk of condensation. Through this air self-circulation loop, it is also possible to avoid the controller from frequently starting and stopping the dehumidification device or running the dehumidification device with high energy consumption for a long time. Therefore, the present invention has a series of energy-saving advantages such as reducing energy consumption and control costs.

[0079] The switchgear according to the present invention can be obtained by slightly modifying an existing switchgear. Therefore, it also has the advantage of reducing the R & D and manufacturing costs of switchgear equipment.

[0080] The above only describes exemplary embodiments of the switchgear according to the present invention. The structure / configuration of the switchgear is not limited to the specific embodiments described herein. On the contrary, each component can be used independently and separately relative to other components described herein. Throughout the specification, references to "one example", "another example", "examples", etc. mean that a certain element / element related to the example (e.g., a feature, structure, and / or characteristic) is included in at least one of the examples described herein, and may and / or may not appear in other examples. Additionally, it will be understood that multiple elements of any of the examples described can be combined in any suitable manner in multiple different examples, unless the context clearly dictates otherwise.

[0081] This specification uses examples to disclose the present invention, including the best mode, and enables any person skilled in the art to practice the present invention. The patentable scope of the present invention is defined by the claims, and may include other examples that occur to those skilled in the art. If these other examples have structural elements that do not differ from the literal language of the claims, or if these other examples include equivalent structural elements that do not differ materially from the literal language of the claims, then these other examples should fall within the scope of the claims.

Claims

1. A switchgear cabinet having at least two unit cabinets arranged side by side, each unit cabinet including a plurality of compartments for accommodating electrical components, the switchgear cabinet including a pressure relief and current collection channel located at the top, characterized in that, The switchgear includes a current-reducing channel provided at the end side in the side-by-side direction of the unit cabinets and extending vertically. The current-reducing channel communicates with a pressure-relief and current-collecting channel at its upper end. The switchgear further includes a current supply pipe extending along the side-by-side direction of the unit cabinets and sequentially passing through the interiors of the unit cabinets. The pipe segments of the current supply pipe located inside each unit cabinet are formed with flow-dividing openings, and the flow-dividing openings are in fluid communication with a predetermined compartment where heat-generating electrical components are installed. The predetermined compartment provides an upward-flowing channel extending from bottom to top and communicating with the pressure-relief and current-collecting channel. The end-side opening of the current supply pipe is in fluid communication with the adjacent current-reducing channel. Thus, an air self-circulation internal loop is formed in the switchgear by the pressure-relief and current-collecting channel, the current-reducing channel, the current supply pipe, and the upward-flowing channel.

2. The switchgear according to claim 1, characterized in that, The current supply pipe passes through the interiors of the unit cabinets in the bottom area of the switchgear.

3. The switchgear according to claim 1, characterized in that, The current supply pipe passing through the interiors of the unit cabinets includes a current supply pipe passing through the cable compartments for accommodating cables in each unit cabinet.

4. The switchgear according to claim 3, characterized in that, The flow-dividing openings formed on the current supply pipe passing through the cable compartments of each unit cabinet are in fluid communication with the cable compartments.

5. The switchgear according to claim 3, characterized in that, The flow-dividing openings formed on the current supply pipe passing through the cable compartments of each unit cabinet are in fluid communication with the breaker compartments for accommodating breakers.

6. The switchgear according to claim 3, wherein, The current supply pipe passing through the cable compartments of each unit cabinet includes a first current supply pipe and a second current supply pipe. The flow-dividing openings on the first current supply pipe are in fluid communication with the cable compartments, and the flow-dividing openings on the second current supply pipe are in fluid communication with the breaker compartments for accommodating breakers.

7. The switchgear according to claim 1 or 3, characterized in that The current supply pipe passing through the interiors of the unit cabinets includes a current supply pipe passing through the breaker compartments for accommodating breakers in each unit cabinet.

8. The switchgear according to any one of claims 1-7, characterized in that, The loads of the main circuit equipment installed in at least two unit cabinets are different.

9. The switchgear according to claim 8, characterized in that, The number of unit cabinets is greater than or equal to 3, and the unit cabinet installed with the main circuit equipment having the highest rated current is generally arranged at the middle position when looking at the switchgear in the side-by-side direction of the unit cabinets.

10. The switchgear according to any one of claims 1-9, characterized in that, The current-reducing channel is defined by the side plate of the end unit cabinet of the switchgear and a cover-shaped end housing buckled on the side plate.

11. The switchgear according to any one of claims 1-10, characterized in that, The switchgear includes a controller for anti-condensation monitoring, a first sensor and a second sensor arranged in the current-reducing channel and signal-connected to the controller. The first sensor is used to sense the temperature of the outer side wall of the current-reducing channel, and the second sensor is used to sense the temperature and relative humidity of the air in the current-reducing channel.

12. The switch cabinet according to claim 11, wherein, The switchgear further includes a dehumidification device arranged in the air self-circulation internal loop. The dehumidification device is signal-connected to the controller, and the controller controls the opening or deactivation of the dehumidification device according to the signals from the first sensor and the second sensor.

13. The switchgear according to any one of claims 1-12, characterized in that, The protection level of the switchgear is IP5X or IP6X.

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