Transformer neutral point grounding protection device with load opening and closing capacity

Abstract

The utility model discloses a transformer neutral point grounding protection device with load opening and closing capacity, a static contact is connected with a wire inlet electrode of a vacuum arc extinguishing device, a wire outlet electrode of the vacuum arc extinguishing device is connected with one end of an auxiliary static contact rod, and the other end of the auxiliary static contact rod is connected or disconnected with a grounding arm moving contact; the lower end of the grounding arm is connected with a main operating rod through a reversing mechanism; the main operating rod is connected with an operating mechanism; and a power input shaft of the vacuum arc-extinguishing device is connected with the insulating operating rod. The utility model has the advantages that in the process of operating the disconnecting switch, after the moving contact and the static contact of the disconnecting switch are separated and before the moving contact and the static contact are closed, the rapid extinguishing of electric arc of a conductive loop is completed by the auxiliary contact system and the vacuum arc extinguisher, and then the moving contact and the static contact of the disconnecting switch are separated and closed in an arc-free and current-free manner. The whole operation process is ensured to be carried out in an arc-free state, so that the occurrence of electric arc and high-frequency resonance phenomena in the operation process is effectively avoided, and the safe operation of a main transformer, a power transmission network and switch equipment is protected.

Description

Technical Field

[0001] The utility model relates to the technical field of electric power equipment, in particular to a transformer neutral point grounding protection device. Background Art

[0002] The neutral point grounding of the transformer in a large substation is achieved by a neutral point grounding protection device, which is composed of an isolating switch, a lightning arrester 10, a discharge gap 9, a current transformer 4, etc. (see Figure 4 ). The neutral point grounding protection device is to install the isolating switch, lightning arrester 10, discharge gap 9, and current transformer 4 on a fixed bracket 3. Among them, the isolating switch is responsible for grounding and isolating the neutral point current of the transformer, and is generally operated when the main transformer is switched or repaired. Since there is a voltage and current to the ground at the neutral point of the operating main transformer, an arc will be generated between its static contact 13 and the moving contact 12 of the grounding arm during the operation of the isolating switch during the switching or maintenance process. This arc will burn the moving / static contacts and shorten the service life of the device. It is also very easy to generate high-frequency resonant overvoltage, which will damage the insulation performance of the main transformer, and will cause millions or even tens of millions of main transformers to burn. At the same time, it also brings safety hazards to other nearby equipment and poses great personal safety to the operator. In particular, the operating mechanism 2 takes about 3 seconds in non-electric operation and about 15 seconds in manual operation. Its speed is much slower than that of the electric one, which increases the arcing time, and the above-mentioned hidden dangers are more prominent. Utility Model Content

[0003] In order to solve the above technical problems, the utility model connects a vacuum arc extinguisher in parallel between the moving contact and the static contact of the grounding arm of the disconnector. The specific technical solution is as follows:

[0004] A transformer neutral point grounding protection device with opening and closing load capacity comprises a bracket, on which a lightning arrester is arranged, the upper part of the lightning arrester is connected to a static contact, the static contact is connected to one end of a discharge gap, the other end of the discharge gap is connected to a current transformer, and the static contact is connected or disconnected to a moving contact of a grounding arm; the static contact is connected to an incoming line pole of a vacuum arc extinguisher, the outgoing line pole of the vacuum arc extinguisher is connected to one end of an auxiliary static contact rod, and the other end of the auxiliary static contact rod is connected or disconnected to a moving contact of the grounding arm; the lower end of the grounding arm is connected to a main operating lever through a reversing mechanism, and the main operating lever is connected to an operating mechanism; the power input shaft of the vacuum arc extinguisher is connected to an insulating operating lever.

[0005] The insulating operating rod is connected to the reversing mechanism through an angle converter.

[0006] The reversing mechanism includes a first bevel gear connected to the main operating lever, the first bevel gear is meshed with the second bevel gear, and the second bevel gear is coaxial with the first transmission gear; the first transmission gear is meshed with the second transmission gear, and the second transmission gear is coaxial with the grounding arm; the first bevel gear is also coaxial with the third bevel gear, the third bevel gear is meshed with the fourth bevel gear, and the fourth bevel gear is coaxial with the insulating operating rod, and the upper end of the insulating operating rod is connected to the vacuum arc extinguisher and to the power input shaft of the operating mechanism of the vacuum fire extinguisher.

[0007] The operating mechanism comprises a motor and a transmission driven by the motor, and a main operating lever is connected to an output end of the transmission.

[0008] The advantages of the utility model are: the vacuum arc extinguisher is connected in series with the auxiliary contact system and connected in parallel to the two ends of the moving and static contacts of the disconnector, so that during the operation of the disconnector, after the moving and static contacts of the disconnector are separated and before they are closed, the conductive circuit is completed by the auxiliary contact system and the vacuum arc extinguisher, and then the moving and static contacts of the disconnector are separated and closed without arc and current. It is ensured that the entire operation process is carried out in a state of no arc, which effectively avoids the occurrence of arc and high-frequency resonance during the operation process, and protects the safe operation of the main transformer, the transmission network and the switchgear. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 The closing state diagram of the utility model device;

[0010] Figure 2 This is a diagram of the opening state of the utility model device;

[0011] Figure 3 It is a structural schematic diagram of a reversing mechanism;

[0012] Figure 4 It is a structural schematic diagram of the prior art;

[0013] In the figure, 1 is a cement pole, 2 is an operating mechanism, 3 is a bracket, 4 is a current transformer, 5 is an insulating operating rod, 6 is a grounding arm, 7 is an auxiliary static contact rod, 8 is a vacuum arc extinguisher, 9 is a discharge gap, 10 is a lightning arrester, 11 is a reversing mechanism, 12 is a grounding arm moving contact, 13 is a static contact, 14 is a main operating lever, 16 is an angle converter, 21 is a first bevel gear, 22 is a second bevel gear, 23 is a first transmission gear, 24 is a second transmission gear, 25 is a third bevel gear, and 26 is a fourth bevel gear. DETAILED DESCRIPTION

[0014] The utility model is described in detail below in conjunction with the accompanying drawings. As shown in the figure, the utility model includes a bracket 3, on which a lightning arrester 10 is arranged. The upper part of the lightning arrester is connected to a static contact 13, the static contact is connected to one end of a discharge gap 9, the other end of the discharge gap 9 is connected to a current transformer 4, and the static contact is connected or disconnected to a moving contact 12 of a grounding arm; the static contact is connected to a connection pole 15 of a vacuum arc extinguisher 8, the outlet pole of the vacuum arc extinguisher is connected to one end of an auxiliary static contact rod 7, and the other end of the auxiliary static contact rod 7 is connected or disconnected to the moving contact 12 of the grounding arm; the lower end of the grounding arm 6 is connected to a main operating lever 14 through a reversing mechanism 11, and the main operating lever is connected to an operating mechanism 2; the vacuum arc extinguisher 8 is connected to an insulating operating lever 5.

[0015] The main operating lever and the insulating operating lever can be driven electrically or manually. For safety reasons, mechanical electric operation is used as much as possible. Therefore, the reversing mechanism can be used to drive the insulating operating lever, that is:

[0016] In order to realize non-manual operation, the insulating operating rod 5 is connected to the reversing mechanism 11 through an angle converter 16 .

[0017] There are many ways to use mechanical operating structures, one of which is a reversing mechanism such as Figure 3 As shown, it includes a first bevel gear 21 connected to the main operating lever, the first bevel gear is meshed with the second bevel gear 22, the second bevel gear 22 is coaxial with the first transmission gear 23; the first transmission gear 23 is meshed with the second transmission gear 24, the second transmission gear 24 is coaxial with the grounding arm 6; the first bevel gear is also coaxial with the third bevel gear 25, the third bevel gear 25 is meshed with the fourth bevel gear 26, the fourth bevel gear 26 is coaxial with the insulating operating rod 5, and the upper end of the insulating operating rod is connected to the vacuum arc extinguisher 8 and to the power input shaft of the operating mechanism of the vacuum fire extinguisher.

[0018] The operating mechanism comprises a motor and a transmission driven by the motor, and a main operating lever is connected to an output end of the transmission.

[0019] In order to ensure that the rotation of the main operating lever and the rotation of the insulating operating lever have a certain angle difference, so as to ensure that the opening and closing of the vacuum interrupter and the disconnection or connection of the moving contact and the static contact of the grounding arm have a certain order, an angle converter is arranged between the reversing structure and the insulating operating lever; the angle converter of this embodiment actually realizes the above function by adjusting the gear ratio between the third bevel gear 25 and the fourth bevel gear 26;

[0020] The specific action process of this utility model is as follows:

[0021] During the opening process, power is output from the operating mechanism box, which rotates through the main operating rod 14 to drive the reversing mechanism 11 to operate. The reversing mechanism 11 converts the rotational motion into the rotation of the grounding arm 6 along its bottom axis, so that the grounding arm 6 moves vertically from top to bottom along the vertical plane. When the moving and static contacts 12 on the upper part of the grounding arm of the disconnector reach a safe distance, the angle converter 16, driven by the main operating rod 14, drives the insulating operating rod 5 to rotate through angle conversion, and inputs power into the mechanism box of the vacuum arc extinguisher 8, triggering the mechanism in the box to quickly separate the moving and static contacts in the vacuum tube in the vacuum arc chamber of the vacuum arc extinguisher 8, and at the same time disconnect the load current. Since the vacuum arc extinguisher 8 has a very strong breaking capacity, the load current is instantly disconnected, and then the moving contact 12 and the static contact 7 of the grounding arm of the auxiliary contact system are separated, realizing the safe separation of the moving contact 12 and the static contact 13 of the protection disconnector in a state of no arc and no current, thereby protecting the moving contact 12 and the static contact 13 of the grounding arm from arc separation. The rapid arc-free interruption of load current avoids the occurrence of high-frequency resonance and protects the safe operation of the main transformer, transmission network and switchgear.

[0022] During the closing process, the operating mechanism box outputs reverse rotation power, which rotates in the opposite direction through the main operating rod 14, driving the reversing mechanism 11 and the angle converter 16 to rotate in the opposite direction at the same time. The reversing mechanism 11 converts the rotational motion into the reverse rotation of the grounding arm 6 along its bottom axis, so that the grounding arm 6 moves upward from the horizontal position to the vertical plane. When the grounding arm moving contact 12 on the upper part of the grounding arm of the disconnector contacts the auxiliary static contact 7 on the vacuum interrupter 8 and continues to rotate in the closing direction, the grounding arm moving contact 12 and the static contact 13 are in contact. After reaching the safety distance, the vacuum arc extinguisher 8, driven by the insulating operating rod 5, triggers the mechanism in the mechanism box of the vacuum arc extinguisher 8, so that the moving and static contacts in the vacuum tube in the vacuum arc extinguishing chamber of the vacuum arc extinguisher 8 are quickly closed, and the grounding circuit of the neutral point of the main transformer is connected. Since the vacuum arc extinguisher 8 has a very strong closing ability, the load current is closed instantly, and then the grounding arm 6 continues to rotate in the closing direction, and the grounding arm moving contact 12 on the grounding arm 6 is closed with the static contact 13 until it is in the closing end position, completing the entire closing process. The grounding arm moving contact 12 and the static contact 13 of the protection disconnector are safely closed in the arc-free state, thereby protecting the grounding arm moving contact 12 and the static contact 13 from arc-free closing. The rapid arc-free closing of the load current avoids the occurrence of high-frequency resonance and protects the safe operation of the main transformer, the transmission network and the switchgear.

Claims

1. A transformer neutral point grounding protection device with opening and closing load capacity, comprising a bracket, a lightning arrester is arranged on the bracket, the upper part of the lightning arrester is connected to a static contact, the static contact is connected to one end of a discharge gap, the other end of the discharge gap is connected to a current transformer, and the static contact is connected or disconnected to a moving contact of a grounding arm; characterized in that: The static contact is connected to the incoming line pole of the vacuum arc extinguisher, the outgoing line pole of the vacuum arc extinguisher is connected to one end of the auxiliary static contact rod, and the other end of the auxiliary static contact rod is connected or disconnected with the moving contact of the grounding arm; the lower end of the grounding arm is connected to the main operating lever through the reversing mechanism, and the main operating lever is connected to the operating mechanism; the power input shaft of the vacuum arc extinguisher is connected to the insulating operating lever.

2. A transformer neutral point grounding protection device with switching load capability according to claim 1, characterized in that: The insulating operating rod is connected to the reversing mechanism through an angle converter.

3. A transformer neutral point grounding protection device with switching load capability according to claim 1, characterized in that: The reversing mechanism includes a first bevel gear connected to the main operating lever, the first bevel gear is meshed with the second bevel gear, and the second bevel gear is coaxial with the first transmission gear; the first transmission gear is meshed with the second transmission gear, and the second transmission gear is coaxial with the grounding arm; the first bevel gear is also coaxial with the third bevel gear, the third bevel gear is meshed with the fourth bevel gear, and the fourth bevel gear is coaxial with the insulating operating rod, the upper end of the insulating operating rod is connected to the power input shaft of the vacuum arc extinguisher, and the power input shaft is connected to the operating mechanism in the vacuum fire extinguisher.

4. A transformer neutral point grounding protection device with switching load capability according to claim 1, characterized in that: The operating mechanism comprises a motor and a transmission driven by the motor, and a main operating lever is connected to an output end of the transmission.

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