CN203630207U - Double-transformer on-line monitoring device of transformer clamping piece grounding current - Google Patents

Abstract

The utility model discloses a dual-transformer on-line monitoring device for the grounding current of a transformer clamp, which solves the problem in the prior art that the test data of the grounding current of a transformer clamp has large deviations and thus affects the safe operation of the transformer. Including the support insulator (13) of the clamp grounding lead wire (13) fixed on the outside of the box body of the transformer oil tank (1), and one end of the clamp ground lead wire (8) is connected to the clamp ground connection piece ( 4) connected together, the other end of the clamp ground lead wire (8) is connected with the ground terminal (6), the clamp ground lead wire (8) is set in the coil of the first current transformer (10), the two Both ends of the secondary coils of the current transformers are respectively connected to two input interfaces of the AD conversion interface circuit (14), and the output end of the AD conversion interface circuit (14) is connected to the single chip microcomputer (16). The more accurate ground current monitoring value of the utility model provides a basis for operation and maintenance personnel to take effective protection measures.

Description

Double Transformer On-Line Monitoring Device for Grounding Current of Transformer Clamp

technical field

The invention relates to a monitoring device for the grounding current of substation equipment, in particular to a device for monitoring the grounding current of a clip in a transformer.

Background technique

When the transformer is running, an uneven electric field will be formed between the transformer winding and the lead wire and the oil tank, and metal components such as the transformer core and its clamps are all in the electric field. The transformer clamp will generate a floating potential through the coupling effect of the capacitor. When the potential difference between the floating potential on the clamp and other components in the transformer reaches a certain value, the insulation between them will be broken down and spark discharge will occur. The transformer will burn out. Therefore, the transformer clamp must be effectively grounded, and multi-point grounding of the transformer clamp should also be avoided. When the transformer clamp is grounded at multiple points, a closed current loop will be formed between the clamp and the ground. Due to the small loop resistance of the clamp, the value of the ground current of the clamp forming the closed current loop is smaller than that of the iron core when the transformer core is grounded. The core grounding current is much larger, even up to hundreds of amperes, such a large grounding current is enough to cause damage to the transformer. There is no on-line monitoring device for clamp grounding current installed on existing transformers. Since the maximum difference between the multi-point grounding of the transformer clamp and the grounding current during normal operation reaches tens of thousands of times, the existing monitoring devices either cannot meet the accuracy requirements, or the monitoring range exceeds the limit. At present, the main means of detecting the ground current of the transformer clamp is to sample through the clamp ammeter. Due to the large magnetic flux leakage near the transformer, the magnetic field strength is also changing at any time, resulting in a large deviation of the test data and the error of the clamp ground current. Judgment, affecting the safe operation of the transformer.

Contents of the invention

The invention provides a dual-transformer on-line monitoring device for the ground current of a transformer clamp, which solves the technical problem in the prior art that the test data deviation of the ground current of the transformer clamp is large, thereby affecting the safe operation of the transformer.

The present invention solves the above technical problems through the following technical solutions:

A dual-transformer on-line monitoring device for the ground current of a transformer clamp, including a transformer oil tank, a transformer iron core is arranged in the transformer oil tank, and a transformer upper clamp and a transformer lower clamp are respectively arranged at both ends of the transformer iron core. The upper clamp of the transformer is respectively provided with the ground connection piece of the clamp and the connecting bolt of the tie plate, the lower connecting bolt of the tie plate is arranged on the lower clamp of the transformer, and the connecting bolt of the tie plate and the lower connection bolt of the tie plate The pull plate, on the outside of the transformer oil tank, is fixedly provided with a clamp ground lead wire supporting insulator, one end of the clip ground lead wire is connected with the clip ground connection piece through the lead wire sleeve, and the other end of the clamp ground lead wire is One end is connected with the ground terminal, and a wooden supporting plate is arranged on the supporting insulator of the grounding lead wire of the clip, and the first current transformer and the second current transformer are respectively fixed on the wooden supporting plate, and the grounding lead out of the clamp is The wire is set in the coil of the first current transformer, the two ends of the secondary coil of the first current transformer are respectively connected with the two input interfaces of the AD conversion interface circuit, and the two ends of the secondary coil of the second current transformer are respectively It is connected with the other two input interfaces of the AD conversion interface circuit, and the output end of the AD conversion interface circuit is connected with the single-chip microcomputer.

A first current transformer installation groove and a second current transformer installation groove are respectively arranged on the upper surface of the wooden pallet, between the first current transformer installation groove and the second current transformer installation groove A wooden bead rotating support shaft is arranged between them, a rotating wooden bead is movably arranged on the rotating wooden bead supporting shaft, and a clamp grounding lead wire installation groove is arranged on the upper surface of the wooden pallet.

An LCD current display, a multi-point grounding fault current recording unit, a multi-point grounding alarm and a background monitoring computer are respectively connected to the single-chip microcomputer.

The invention greatly reduces the working intensity of the operators, and can monitor the change of the clamp grounding current value online in real time in the monitoring background, and the more accurate grounding current monitoring value provides a reliable basis for the operation and maintenance personnel to take effective measures. The safe operation of the transformer is guaranteed. the

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic structural view of wooden pallet 12 of the present invention in a top view direction;

Fig. 3 is a schematic structural view of the wooden pallet 12 of the present invention in the front view direction;

FIG. 4 is a schematic view of the structure of the wooden pallet 12 of the present invention in the front view direction after two current transformers are installed.

Detailed ways

The present invention is described in detail below in conjunction with accompanying drawing:

A dual transformer on-line monitoring device for ground current of a transformer clamp, comprising a transformer oil tank 1, a transformer iron core 2 is arranged in the transformer oil tank 1, and a transformer upper clamp 3 and a transformer upper clamp 3 are respectively arranged at both ends of the transformer iron core 2 The lower clamp 5 is respectively provided with the clamp ground connection piece 4 and the connecting bolt 21 on the pull plate on the upper clamp 3 of the transformer. A pull plate 9 is set between the bolt 21 and the lower connecting bolt 20 of the pull plate, and a clamp ground lead wire support insulator 13 is fixedly installed outside the box body of the transformer oil tank 1, and one end of the clamp ground lead wire 8 passes through the lead wire sleeve 7 is connected with the clamp ground connection piece 4, the other end of the clamp ground lead wire 8 is connected with the ground terminal 6, and a wooden supporting plate 12 is arranged on the support insulator 13 of the clamp ground lead wire. The first current transformer 10 and the second current transformer 11 are respectively fixedly arranged on the supporting plate 12, and the grounding lead wire 8 of the clip is arranged in the coil of the first current transformer 10, and the secondary coil of the first current transformer 10 The two ends of the second current transformer 11 are respectively connected with two input interfaces of the AD conversion interface circuit 14, and the two ends of the secondary coil of the second current transformer 11 are respectively connected with the other two input interfaces of the AD conversion interface circuit 14, and the AD conversion interface circuit 14 The output terminal of is connected with single-chip microcomputer 16.

A first current transformer installation groove 22 and a second current transformer installation groove 23 are respectively arranged on the upper surface of the wooden pallet 12, and the first current transformer installation groove 22 and the second current transformer installation groove A wooden bead rotating support shaft 24 is arranged between the installation grooves 23, a rotating wooden bead 25 is movable on the rotating wooden bead supporting shaft 24, and a clip is provided on the upper surface of the wooden pallet 12 for grounding Outlet installation groove 26.

The single-chip microcomputer 16 is respectively connected with an LCD current display 15 , a multi-point ground fault current recording unit 17 , a multi-point ground alarm 19 and a background monitoring computer 18 .

The purpose of setting two current transformers on the wooden pallet 12 is to accurately monitor the grounding current of the transformer clip. The second current transformer 11 is to monitor the current generated due to transformer magnetic flux leakage, and the first current transformer 10 is to monitor the sum of the clamp ground current and the current generated by magnetic flux leakage, and the transformer clamp ground current is the sum of the two current transformers detect the difference in current. In the prior art, clamp-on ammeters are used to sample the ground current of the clamp. The reason for the inaccurate detection value is that the magnetic flux leakage near the transformer is large, and the magnetic flux leakage is unevenly distributed on the plane. The clamp-on ammeter The magnitude of the magnetic flux leakage varies with the different sampling locations, and the value measured by the clamp ammeter includes the induced current generated by the magnetic flux leakage in addition to the clamp ground current. The present invention uses two current transformers to detect the clamp grounding current, which greatly improves the accuracy of the clamp grounding current detection, eliminates the interference of magnetic flux leakage through the two current transformers, and solves the problem that the field current test data is too large .

The installation position of the current transformer is different, and the data detection will have deviation. When the two current transformers are not on the same level, it is easy to cause different magnetic flux leakage, which will bring certain errors to the current detection results, and the current transformer will vibrate to a certain extent when working, and it is easy to cause the current transformer to fall off after working for a long time. In the present invention, the two current transformers are placed on the same plane through the wooden supporting board 12 and the rotating wooden bead 25, thereby improving the stability and testing accuracy of the device.

The invention can automatically record the magnitude and time of the fault current when the clips are grounded at multiple points, so as to improve reference information for operation and maintenance personnel. In addition, local and remote alarm signal functions are also set up to enable operation and maintenance personnel to understand fault information in real time. When the grounding current of the clip is greater than 0.1A, the local alarm indicator light is on, and the alarm signal is transmitted to the background for reference by operation and maintenance personnel.

The clamping piece grounding current display range of the invention is wide, and can meet precision requirements in different ranges. The present invention adopts a segment display algorithm by setting a computer software program, designs different detection ranges and adopts different precisions in the program, and solves the problems of field test overrun and insufficient display precision. Within the maximum current range of 100A, it is displayed in segments according to different ranges. When the grounding current is less than 0.1A, the display accuracy level is 0.1mA; when the grounding current is between 0.1A and 1A, the display accuracy level is 0.001A; when When the ground current is 1A to 100A, the display accuracy level is 0.01A.

Claims (3)

1. two mutual inductor on-Line Monitor Device of an apparatus for fixing transformer ground current, comprise oil tank of transformer (1), in oil tank of transformer (1), be provided with transformer core (2), be respectively arranged with transformer upper clamping piece (3) and transformer lower clamping piece (5) at the two ends of transformer core (2), it is characterized in that, on transformer upper clamping piece (3), be respectively arranged with coupling bolt (21) on folder grounding connection sheet (4) and arm-tie, on transformer lower clamping piece (5), be provided with coupling bolt under arm-tie (20), under coupling bolt on arm-tie (21) and arm-tie, between coupling bolt (20), be provided with arm-tie (9), casing outside at oil tank of transformer (1) is fixedly installed folder ground outlet supporting insulator (13), one end of folder ground outlet (8) links together by extension line sleeve pipe (7) and folder grounding connection sheet (4), the other end of folder ground outlet (8) and earth terminal (6) link together, on folder ground outlet supporting insulator (13), be provided with wooden supporting plate (12), on wooden supporting plate (12), be fixedly installed respectively the first current transformer (10) and the second current transformer (11), folder ground outlet (8) is arranged in the coil of the first current transformer (10), the two ends of the secondary coil of the first current transformer (10) are connected with two input interfaces of AD conversion interface circuit (14) respectively, the two ends of the secondary coil of the second current transformer (11) are connected with another two input interfaces of AD conversion interface circuit (14) respectively, the output terminal of AD conversion interface circuit (14) is connected with single-chip microcomputer (16).

2. two mutual inductor on-Line Monitor Device of a kind of apparatus for fixing transformer ground current according to claim 1, it is characterized in that, on the upper face of wooden supporting plate (12), be respectively arranged with the first current transformer groove (22) and the second current transformer installation groove (23) are installed, install between groove (22) and the second current transformer installation groove (23) and be provided with wooden press strip rotating support shaft (24) at the first current transformer, on the wooden press strip back shaft of rotation (24), be movably set with the wooden press strip of rotation (25), on the upper face of wooden supporting plate (12), be provided with folder ground outlet mounting groove (26).

3. two mutual inductor on-Line Monitor Device of a kind of apparatus for fixing transformer ground current according to claim 1 and 2, it is characterized in that, on single-chip microcomputer (16), be connected with respectively LCD Current Display (15), multipoint earthing of clamping piece fault current record cell (17), multipoint earthing of clamping piece alarm (19) and background monitoring computer (18).

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