Dry-type transformer heat dissipation device with external fan, automatic start-stop circuit of dry-type transformer heat dissipation device and transformer

Abstract

The utility model relates to the technical field of transformer heat dissipation, in particular to a dry-type transformer heat dissipation device with an external fan, an automatic start-stop circuit of the dry-type transformer heat dissipation device and a transformer. The heat dissipation device comprises two fans and three sections of air ducts, the fans are arranged outside the transformer box body, the two fans are respectively connected with the two sections of air ducts with the same length through flange plates, and the two sections of air ducts with the same length are respectively connected with the third section of air duct through two elbows. All the air ducts jointly form a U-shaped structure which surrounds the periphery of a transformer winding and is located below the winding, and ventilation holes are formed in the air ducts directly connected with the draught fan. The automatic starting and stopping circuit of the external fan is matched with the temperature controller, starting and stopping of the two fans can be automatically controlled, the two fans are designed to be interlocked, when one fan breaks down, the other fan is automatically started, an indicating lamp is used for alarming, and the cooling facility is simple in structure and convenient to maintain and has good application prospects.

Description

Technical Field

[0001] The utility model relates to the technical field of transformer heat dissipation, in particular to a dry-type transformer heat dissipation device with an external fan, its automatic start-stop circuit and transformer. Background Art

[0002] At present, the cooling fans of dry-type transformers usually adopt cross-flow fans built in the bottom of the transformer box body, generally divided into two sides, A and B, with 3 fans installed on each side. Controlled by a temperature controller, they ventilate and dissipate heat from the transformer windings. For example, the dry-type transformer fans or fan groups in Chinese patents CN2312512Y and CN202996495U are all arranged at the bottom of the transformer box body. Because of their installation method inside the transformer box body, once a failure occurs, the transformer must be shut down to replace the fan, which affects production. In view of the current difficult problem of replacing and repairing fans, Chinese patent CN203300379U proposes a device for online replacing the cooling fans of dry-type transformers. By means of erecting a support, the cooling fan can be moved out of the dry-type transformer, but it still needs to be replaced in cooperation with the power outage of the unit during use; in Chinese patent CN204596575U, the fan is connected to the horizontal air duct and the vertical air duct in sequence, so that the fan is far away from the winding to achieve the effect of online replacing the cooling fan, but the fan is still located in the outer cover, and when replacing the fan, heat dissipation at the position of the fan to be replaced cannot be realized.

[0003] Therefore, there is an urgent need to design and manufacture an external fan device that is convenient for maintenance on the premise of meeting the stable and continuous cooling of the transformer. Summary of the Utility Model

[0004] In order to overcome the deficiencies of the existing technologies, the utility model designs a dry-type transformer cooling device with an external fan and an automatic start-stop circuit, which can quickly repair or replace the transformer fan without shutting down. The specific technical solutions of the utility model are as follows:

[0005] A dry-type transformer heat dissipation device with an external fan includes: two fans and three air ducts, where two of the air ducts are of equal length. The two fans are respectively connected to the two air ducts of equal length through flange plates. The two air ducts of equal length are respectively connected to the third air duct through two elbows. All the air ducts together form a "U" - shaped structure, and ventilation holes are opened on the air ducts directly connected to the fans.

[0006] Furthermore, a check valve is connected through a flange plate at the connection between the fan and the air duct.

[0007] Furthermore, the diameter of the ventilation hole is 4 - 6 mm.

[0008] The automatic start-stop circuit of the dry-type transformer cooling device with the fan outside includes a trigger circuit and a control circuit. In the trigger circuit, a temperature control switch is connected in series with a first intermediate relay. The control circuit includes a main circuit and a control circuit: The main circuit includes a first circuit and a second circuit. A first switch, the main contacts of a second contactor, a first fuse, and a first fan are connected in series in sequence to form the first circuit. A second switch, the main contacts of a fourth contactor, a second fuse, and a second fan are connected in series in sequence to form the second circuit. The first circuit and the second circuit are connected in parallel. The control circuit includes a control branch circuit, a first fan start circuit, and a second fan start circuit: The control branch circuit is formed by connecting a second normally open contact in series with a third intermediate relay. The first fan start circuit is formed by connecting a fifth normally closed contact in series with a second intermediate relay. The second fan start circuit is formed by connecting a third normally closed contact, a sixth normally closed contact, and a fourth intermediate relay in series. Among them, the first fan start circuit and the second fan start circuit are connected in parallel and then connected in series with a first normally open contact, then connected in parallel with the control branch circuit, and then connected in series with a main switch and a fuse. The main switch and the fuse are located at the power input end.

[0009] Further, the control circuit further includes a first fan operation circuit and a second fan operation circuit. The first fan operation circuit is formed by connecting a third normally open contact and a first indicator light in series. The second fan operation circuit is formed by connecting a fourth normally open contact and a second indicator light in series. Among them, the first fan start circuit, the second fan start circuit, the first fan operation circuit, and the second fan operation circuit are connected in parallel and then connected in series with a first normally open contact, then connected in parallel with the control branch circuit, and then connected in series with a main switch and a fuse. The main switch and the fuse are located at the power input end. The fuse or the intermediate relay controls the opening and closing of the corresponding normally open contacts, normally closed contacts, and the main contacts of the contactor: Among them, the energization or de-energization of the first intermediate relay controls the opening and closing change of the first normally open contact; the energization or de-energization of the third intermediate relay controls the opening and closing changes of the third normally open contact and the third normally closed contact; the energization or de-energization of the second intermediate relay controls the opening and closing changes of the main contacts of the second contactor and the second normally open contact; the energization or de-energization of the fourth intermediate relay controls the opening and closing changes of the main contacts of the fourth contactor and the fourth normally open contact; the operation of the first fuse controls the opening and closing change of the fifth normally closed contact; the operation of the second fuse controls the opening and closing change of the sixth normally closed contact.

[0010] A transformer equipped with the above dry-type transformer cooling device with the fan outside includes a transformer box body and a transformer winding located inside the box body. The two fans are located outside the transformer box body. The "U"-shaped air duct is arranged around the transformer winding and is located below the transformer winding. Specifically, the ventilation duct of the cooling device is installed around the A, B, and C phase windings and is located below the windings.

[0011] The beneficial effects of the present utility model are:

[0012] (1) Two fans are paired with a U-shaped air duct to form a surrounding distribution on the high- and low-voltage sides of the transformer. The fans are placed outside the transformer housing, which facilitates the maintenance or replacement of the fans. In addition, the setting of the U-shaped air duct makes the air outlet around the transformer winding uniform and stable when any fan is working, and it will not cause insufficient air volume in some spaces due to the failure of any fan. Moreover, one of the two fans is used as the main fan and the other as the standby fan. When the main fan fails, the standby fan is turned on, and the transformer does not need to be shut down.

[0013] (2) The dry-type transformer cooling device with external fans is controlled by an automatic start-stop circuit. In cooperation with a dry-type transformer temperature controller, it automatically controls the start and stop of the two fans, and the circuit controls the two fans to be interlocked. When one fan fails, the other fan automatically turns on and further alarms. This cooling facility has a simple structure and is easy to repair, and it can realize the maintenance of the fans without shutting down the transformer. Description of the Drawings

[0014] The following further describes the embodiments of the present invention with reference to the drawings, where:

[0015] Figure 1 It shows the application top view of the present invention;

[0016] Figure 2 It shows the automatic start-stop circuit of the present invention.

[0017] Among them, 1, 2: fans; 3: flange; 4: check valve; 5: air duct; 6: ventilation hole; 7: elbow; 8: transformer winding; Specific Embodiments

[0018] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further details the present invention through specific embodiments with reference to the drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] Two 1.5KW fans are adopted. The two fans 1 and 2 are located outside the transformer box. The check valve 4 is connected through the flange 3, and then two sections of air ducts of equal length are respectively connected. The outlet diameter of the air duct is 200mm, and the length of the air duct is about 2m. The two sections of air ducts are connected to the third section of air duct through the elbow 7. The length of the third section of air duct is 0.8m. The three sections of air ducts 5 form a U shape and form a surrounding distribution on the high- and low-voltage sides of the transformer, and are located below the ABC three phases of the transformer winding. Three groups of ventilation holes 6 with a diameter of about 5mm are provided on the upper surface of the two sections of air ducts of equal length, and the transformer winding is ventilated and cooled through the ventilation holes 6.

[0020] This dry-type transformer cooling facility is mainly used for cooling and heat dissipation of dry-type transformers. When in use, two fans are powered on in two circuits. When the temperature reaches the fan start temperature set by the temperature controller, the main fan 1 (the first fan) operates, and the check valve 4 fixed by the flange 3 opens. The air volume enters the air duct 5 and then is sent to the transformer winding through the ventilation holes 6, so as to achieve the purpose of cooling the dry-type transformer winding 8. When the temperature of the transformer winding drops to the fan shutdown temperature set by the temperature controller, the fan 1 shuts down and the check valve 4 closes. During operation, if the main fan 1 fails, the standby fan 2 (the second fan) will automatically start. Generally, the fan start temperature is set at 80 °C and the stop temperature is set at 60 °C.

[0021] The above-mentioned dry-type transformer heat dissipation device with external fans is equipped with an automatic start-stop circuit. In the attached drawing, the combination of the same letters and numbers represents components that control or are controlled by each other. That is, the energization or de-energization of the first intermediate relay ZJ1 controls the opening and closing changes of the first normally open contact ZJ1; the energization or de-energization of the third intermediate relay ZJ2 controls the opening and closing changes of the third normally open contact ZJ2 and the third normally closed contact ZJ2; the energization or de-energization of the second intermediate relay KM1 controls the opening and closing changes of the second contactor main contact KM1 and the second normally open contact KM1; the energization or de-energization of the fourth intermediate relay KM2 controls the opening and closing changes of the fourth contactor main contact KM2 and the fourth normally open contact KM2; the operation of the first fuse KH1 controls the opening and closing changes of the fifth normally closed contact KH1; the operation of the second fuse KH2 controls the opening and closing changes of the sixth normally closed contact KH2. At the same time, in the attached drawing, WJ represents the temperature control switch, QF represents the main switch, QF1 represents the first switch, QF2 represents the second switch, and FU represents the fuse.

[0022] The automatic start-stop circuit includes a trigger circuit and a control circuit. In the trigger circuit, the temperature control switch WJ is connected in series with the first intermediate relay ZJ1. The control circuit includes a main circuit and a control loop: the main circuit power supply is a three-phase AC power supply. The main circuit includes a first circuit and a second circuit. The first switch QF1, the main contact KM1 of the second contactor, the first fuse KH1, and the first fan are connected in series in sequence to form the first circuit. The second switch QF2, the main contact KM2 of the fourth contactor, the second fuse KH2, and the second fan are connected in series in sequence to form the second circuit. The first circuit and the second circuit are connected in parallel. One phase of the three-phase AC power supply of the main circuit is arbitrarily connected to the live wire of the control loop. The control loop includes a control branch loop, a first fan start loop, a second fan start loop, a first fan operation loop, and a second fan operation loop: the control branch loop is formed by the second normally open contact KM1 connected in series with the third intermediate relay ZJ2. The first fan start loop is formed by the fifth normally closed contact KH1 connected in series with the second intermediate relay KM1. The second fan start loop is formed by the third normally closed contact ZJ2, the sixth normally closed contact KH2, and the fourth intermediate relay KM2 connected in series. The first fan operation loop is formed by the third normally open contact ZJ2 connected in series with the first indicator light. The second fan operation loop is formed by the fourth normally open contact KM2 connected in series with the second indicator light. Among them, the first fan start loop, the second fan start loop, the first fan operation loop, and the second fan operation loop are connected in parallel and then connected in series with the first normally open contact ZJ1, and then connected in parallel with the control branch loop, and then connected in series with the main switch QF and the fuse FU. The main switch QF and the fuse FU are located at the power input end.

[0023] During operation, close the main switch QF, the first switch QF1, and the second switch QF2. The temperature control switch WJ in the trigger circuit is connected to the coil of the first intermediate relay ZJ1. When the temperature reaches the set value for fan startup, the temperature control switch WJ closes, and the coil of the first intermediate relay ZJ1 is energized, causing the first normally open contact ZJ1 in the control loop to close. The second intermediate relay KM1 is energized, controlling its corresponding second normally open contact KM1 and the main contact KM1 of the second contactor to close. Subsequently, the third intermediate relay ZJ2 is energized, controlling its corresponding third normally closed contact ZJ2 to open and the third normally open contact ZJ2 to close. That is, the first circuit, the control branch loop, the first fan start loop, and the first fan operation loop form a path, the first fan starts, and the first indicator light for operation lights up. At the same time, the second fan start loop is disconnected.

[0024] When the first fan fails, the first fuse KH1 operates, controlling its corresponding fifth normally closed contact KH1 to disconnect. Subsequently, the second intermediate relay KM1 loses power, causing its corresponding second normally open contact KM1 and the main contact KM1 of the second contactor to resume disconnection. The third intermediate relay ZJ2 then loses power, controlling its corresponding third normally closed contact ZJ2 to resume closure and its third normally open contact ZJ2 to resume disconnection, enabling the coil of the fourth intermediate relay KM2 to be energized. This controls its corresponding fourth contactor main contact KM2 and fourth normally open contact KM2 to close, that is, the second circuit, the second fan startup circuit, and the second fan operation circuit form a path, starting the second fan. The second operation indicator light is on, and the first operation indicator light is off. This achieves the effect of the first fan operating under normal circumstances and immediately starting the second fan when the first fan fails. At the same time, through the on and off states of the first indicator light and the second indicator light, it plays the role of alarming for fan failures.

[0025] Furthermore, when the second fan fails, the second fuse KH2 operates, controlling its corresponding sixth normally closed contact KH2 to disconnect. Subsequently, the fourth intermediate relay KM2 loses power, causing its corresponding fourth normally open contact KM2 and the main contact KM2 of the fourth contactor to resume disconnection, thereby opening the second circuit, the second fan startup circuit, and the second fan operation circuit. The second indicator light goes out, alarming the failure of the second fan.

[0026] The above text describes some exemplary embodiments of the present invention. It can be understood that the above embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention. The features in these embodiments can be recombined in a suitable manner, and the resulting solutions are still within the protection scope required by the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without creative efforts, that is, all modifications, equivalent replacements, and improvements made within the spirit and principle of this application, fall within the protection scope required by the present invention.

Claims

1. A dry-type transformer cooling device with an external fan, characterized in that, Comprising: Two fans and three sections of air ducts, where two sections of the air ducts are of equal length. The two fans are respectively connected to the two sections of air ducts of equal length through flange plates. The two sections of air ducts of equal length are respectively connected to the third section of air duct through two elbows. All the air ducts together form a "U" - shaped structure, and ventilation holes are provided on the air ducts directly connected to the fans.

2. The dry-type transformer cooling device with an external fan according to claim 1, wherein, A check valve is connected through a flange plate at the connection between the fan and the air duct.

3. The dry-type transformer heat dissipation device with an external fan according to claim 1, characterized in that The diameter of the ventilation hole is 4 - 6 mm.

4. An automatic start-stop circuit is used for the dry-type transformer heat dissipation device outside the fan according to any one of claims 1-3, and is characterized in that, Comprising a trigger circuit and a control circuit. In the trigger circuit, a temperature control switch is connected in series with a first intermediate relay. The control circuit includes a main circuit and a control circuit: The main circuit includes a first circuit and a second circuit. A first switch, the main contact of a second contactor, a first fuse, and a first fan are connected in series in sequence to form the first circuit. A second switch, the main contact of a fourth contactor, a second fuse, and a second fan are connected in series in sequence to form the second circuit. The first circuit and the second circuit are connected in parallel. The control circuit includes a control branch circuit, a first - fan starting circuit, and a second - fan starting circuit: The control branch circuit is formed by connecting a second normally - open contact in series with a third intermediate relay. The first - fan starting circuit is formed by connecting a fifth normally - closed contact in series with a second intermediate relay. The second - fan starting circuit is formed by connecting a third normally - closed contact, a sixth normally - closed contact, and a fourth intermediate relay in series. Among them, the first - fan starting circuit and the second - fan starting circuit are connected in parallel and then connected in series with a first normally - open contact, then connected in parallel with the control branch circuit, and then connected in series with a main switch and a fuse. The main switch and the fuse are located at the power input end.

5. The automatic start-stop circuit according to claim 4, wherein The control circuit further includes a first - fan running circuit and a second - fan running circuit. The first - fan running circuit is formed by connecting a third normally - open contact and a first indicator light in series. The second - fan running circuit is formed by connecting a fourth normally - open contact and a second indicator light in series. Among them, the first - fan starting circuit, the second - fan starting circuit, the first - fan running circuit, and the second - fan running circuit are connected in parallel and then connected in series with a first normally - open contact, then connected in parallel with the control branch circuit, and then connected in series with a main switch and a fuse. The main switch and the fuse are located at the power input end.

6. A transformer is equipped with the dry-type transformer heat dissipation device with an external fan as described in any one of claims 1-3, and includes a transformer box body and a transformer winding located inside the box body, and is characterized in that, The two fans are located outside the transformer box body. The "U" - shaped air duct is arranged around the transformer winding and is located below the transformer winding.

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