CN215415825U - Converter transformer CT secondary circuit abnormal grounding current detection system - Google Patents
Converter transformer CT secondary circuit abnormal grounding current detection system Download PDFInfo
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Abstract
The utility model relates to a converter transformer CT secondary circuit abnormal grounding current detection system, wherein the a phase, the B phase and the C phase of a valve side sleeve CT secondary winding secondary side winding of the system are respectively connected with the A phase, the B phase and the C phase of a converter transformer body terminal box, the output ends of the A phase, the B phase and the C phase of the converter transformer body terminal box are respectively connected with a converter transformer public terminal box, the output end of the converter transformer public terminal box is connected with the input end of a converter transformer air flow protection, the public end output end of the converter transformer air flow protection is connected with the public input end of the converter transformer public terminal box, the public input end of the converter transformer public terminal box is also connected with a grounding copper bar through a cable, a high-precision current pressure sensor is arranged on the cable at the grounding copper bar, and the high-precision current pressure sensor is connected with a fault recording device. The utility model can accurately measure the slight change of the grounding current.
Description
Technical Field
The utility model relates to the technical field of converter transformers, and provides a converter transformer CT secondary circuit abnormal grounding current detection system.
Background
The converter transformer is a power transformer connected between a converter bridge and an alternating current system, is a main device of a direct current transmission system, and main parameters of the converter transformer are determined according to special requirements of the direct current system. And the converter transformer is adopted to realize the connection of the converter bridge and the alternating current bus and provide a three-phase commutation voltage with ungrounded neutral point for the converter bridge. The converter transformer and the converter bridge constitute a main body of the converter unit.
The converter transformer has the following functions in a direct-current transmission system:
(1) transmitting power;
(2) the leakage reactance of the converter transformer can play a role in limiting fault current;
(3) converting the AC system voltage to a commutation voltage required by the converter;
(4) the direct current part and the alternating current system are isolated in an insulated mode, so that direct short circuit caused by grounding of a neutral point of the alternating current system and grounding of a neutral point of the direct current part is avoided, and phase change cannot be carried out;
(5) by utilizing different connection methods of transformer windings, two groups of three-phase symmetrical commutation voltages with equal amplitude and 30-degree phase difference (fundamental wave electrical angle) are provided for two converters connected in series to realize twelve-pulse commutation;
(6) the lightning impulse overvoltage waves intruding into the converter station along the AC line are buffered and restrained.
The converter transformer valve side sleeve pouring type CT secondary wiring terminal is arranged right below the rising seat body, the gap between the converter transformer valve side sleeve pouring type CT secondary wiring terminal and the rising seat is small, vibration generated when the converter transformer is operated in a variable length period is superposed with downward acting force of the weight of the pouring type CT measuring device, so that part of secondary lead wires are contacted with the rising seat shell, friction discharge is generated, and a CT loop is shunted. At present, no effective monitoring means exists, abnormality cannot be found at the initial stage of grounding, and operation and maintenance personnel can find the abnormality only when protection abnormality is alarmed, so that the potential hazard of tripping accidents caused by protection actions exists.
Disclosure of Invention
The utility model provides a system for detecting abnormal grounding current of a current conversion transformer CT secondary circuit, and provides real-time recording of the grounding current, aiming at solving the problem that operation and maintenance personnel can find abnormality at the initial grounding stage of the CT circuit and avoiding tripping accidents caused by protection misoperation.
In order to achieve the purpose, the utility model adopts the following technical scheme:
a converter transformer CT secondary circuit abnormal grounding current detection system is characterized in that a phase, a phase B phase and a phase C of a valve side sleeve CT secondary winding secondary side winding of the system are respectively connected with an A phase, a B phase and a C phase of a converter transformer body terminal box, the output ends of the A phase, the B phase and the C phase of the converter transformer body terminal box are respectively connected with a converter transformer public terminal box, the output end of the converter transformer public terminal box is connected with the input end of a converter transformer air volume protection, the public end output end of the converter transformer air volume protection is connected with the public input end of the converter transformer public terminal box, the public input end of the converter transformer public terminal box is further connected with a grounding copper bar through a cable, a high-precision current pressure sensor is arranged on the cable at the grounding copper bar, and the high-precision current pressure sensor is connected with a fault wave recording device.
Furthermore, the grounding current of the high-precision current pressure sensor is approximately 0 when no fault occurs, and the grounding current reaches 1A when the fault occurs.
Further, the transformation ratio of the high-precision current pressure sensor is 5/1A or 1/1A.
Further, the cable specification is 4 × 2.5 signal cable.
Furthermore, the fault recorder is a device capable of receiving real-time signals and processing images.
The utility model has the beneficial effects that:
because the grounding current of the secondary circuit of the valve side sleeve CT of the converter transformer is small, the current is not easy to capture when the CT sinks at the initial stage. The utility model can accurately measure the slight change of the grounding current by measuring at the grounding copper bar through the high-precision current transformer, and can record the wave in real time so as to analyze the waveform of the grounding current by transmitting the grounding current to the fault recording and broadcasting device.
Drawings
FIG. 1 is a schematic structural diagram of a converter transformer CT secondary circuit;
FIG. 2 is a schematic diagram of the main structure of the present invention.
The figure is marked with: 1. the transformer comprises a valve side sleeve CT secondary winding, 2, a converter transformer body terminal box, 3, a converter transformer public terminal box, 4, converter transformer air volume protection, 5, a grounding copper bar, 6, a high-precision current transformer, 7 and a fault recorder.
Detailed Description
The utility model is further described with reference to the accompanying drawings in which:
a converter transformer CT secondary circuit abnormal grounding current detection system is characterized in that a phase, a phase B phase and a phase C of a secondary side winding of a valve side sleeve CT secondary winding 1 of the system are respectively connected with an A phase, a B phase and a C phase of a converter transformer body terminal box 2, output ends of the A phase, the B phase and the C phase of the converter transformer body terminal box 2 are respectively connected with a converter transformer public terminal box 3, an output end of the converter transformer public terminal box 3 is connected with an input end of a converter transformer air quantity protection 4, a public end output end of the converter transformer air quantity protection 4 is connected with a public input end of the converter transformer public terminal box 3, the public input end of the converter transformer public terminal box 3 is further connected with a grounding copper bar 5 in the converter transformer public terminal box through a cable, a high-precision current pressure sensor 6 is installed on a cable slightly above the grounding copper bar 5, and the high-precision current pressure sensor 6 is connected with a fault recording device 7. The printer connected with the fault recorder 7 can print the processed secondary circuit grounding current. According to the utility model, the high-precision current transformer is arranged on the CT secondary circuit grounding copper bar of the current conversion transformer public terminal box, and the current signal is transmitted to the fault recording and broadcasting device through the cable.
The primary side of the high-precision current pressure sensor 6 is the converter transformer valve side current secondary circuit grounding current, the grounding current of the high-precision current pressure sensor 6 is approximately 0 when no fault exists, and the short-time grounding current reaches 1A.
The transformation ratio of the high-precision current pressure sensor 6 is 5/1A or 1/1A. The high-precision current pressure sensor 6 has high sensitivity. The high-precision current transformer is small in size, high in precision and convenient to install. Because of change of current transformer body terminal box 2 interior wiring intensive, the below ground copper bar 5 connecting cable is more, need reduce this high accuracy current pressure sensor 6 volume in order to guarantee that this device of installation can not influence other cables in the case.
The signal transmission cable specification is 4 x 2.5 signal cable. The signal transmission cable is a signal cable with high reliability, is little influenced by weather conditions and surrounding environment, and has stable transmission performance and high reliability.
The fault recorder 7 is a device capable of receiving real-time signals and processing images. The fault recording device 7 can correctly receive the signal transmitted by the current transformer and store the recording image. The fault recorder can set a value in it and compare it with the current signal, and can send out alarm information when the line is crossed.
The loop of the phase a of the valve side bushing CT secondary winding 1 is: the phase a of the valve side bushing CT secondary winding 1 is connected with the phase A terminal 13 of the converter transformer body terminal box 2, the phase A terminal 13 of the converter transformer body terminal box 2 is connected with the phase A terminal 31 of the converter transformer common terminal box 3, the phase A terminal 31 of the converter transformer common terminal box 3 is connected with the phase A terminal 1 of the converter transformer amount protection 4, the phase A terminal 1 of the converter transformer amount protection 4 is connected with the phase A terminal 4 of the converter transformer amount protection 4, the phase A terminal of the converter transformer amount protection 4 is connected with the phase A terminal 34 of the common input end of the converter transformer common terminal box 3, the phase A terminal 13 of the converter transformer body terminal box 2 is finally connected with the phase A of the valve side bushing CT secondary winding 1 to form a complete loop.
The b-phase loop of the valve side bushing CT secondary winding 1 is: the phase B of the valve side bushing CT secondary winding 1 is connected with the phase B terminal 13 of the converter transformer body terminal box 2, the phase B terminal 13 of the converter transformer body terminal box 2 is connected with the phase B terminal 32 of the converter transformer common terminal box 3, the phase B terminal 32 of the converter transformer common terminal box 3 is connected with the phase B terminal 2 of the converter transformer amount protection 4, the phase B terminal 2 of the converter transformer amount protection 4 is connected with the phase 5 of the common end output end of the converter transformer amount protection 4, the common end output end of the converter transformer amount protection 4 is connected with the phase 34 of the common input end of the converter transformer common terminal box 3, the common input end of the converter transformer common terminal box 3 is further connected with the phase B terminal 14 of the converter transformer body terminal box 2, and the phase B terminal 14 of the converter transformer body terminal box 2 is finally connected with the phase B of the valve side bushing CT secondary winding 1 to form a complete loop.
The c-phase loop of the valve side bushing CT secondary winding 1 is: the C phase of the valve side bushing CT secondary winding 1 is connected with the C phase terminal 13 of the converter transformer body terminal box 2, the C phase terminal 13 of the converter transformer body terminal box 2 is connected with the terminal 33 of the converter transformer common terminal box 3, the terminal 33 of the converter transformer common terminal box 3 is connected with the terminal 3 of the converter transformer gas amount protection 4 of the terminal, the terminal 3 of the converter transformer gas amount protection 4 is connected with the terminal 6 of the common end output end of the converter transformer gas amount protection 4, the common end output end of the converter transformer gas amount protection 4 is connected with the terminal 34 of the common input end of the converter transformer common terminal box 3, the common input end of the converter transformer common terminal box 3 is further connected with the C phase terminal 14 of the converter transformer body terminal box 2, and the C phase terminal 14 of the converter transformer body terminal box 2 is finally connected with the C phase of the valve side bushing CT secondary winding 1 to form a complete loop.
The three-phase current of the secondary side winding of the valve side sleeve CT secondary winding 1 is led to a converter transformer public terminal box 3 from a converter transformer body terminal box 2, and the public end of the converter transformer side sleeve CT secondary circuit is grounded in the converter transformer public terminal box 3 through a grounding copper bar 5. A high-precision current transformer 6 is arranged at the position of the grounding copper bar 5 of the current conversion transformer public terminal box 3, and the high-precision current transformer 6 is used for measuring the current of the grounding copper bar in real time. The high-precision current transformer 6 transmits a current signal to a local fault recorder 7 through a 4 multiplied by 2.5mm signal cable, and the fault recorder 7 stores and records a grounding current recording image through processing, so that an operation and inspection person can observe and analyze the change trend of the grounding current of a valve side sleeve CT secondary circuit of the converter transformer during normal operation. The fault recorder 7 compares the grounding current data, and when the current exceeds a fixed value, an alarm is given out so that operating personnel can make a response instantly when the CT loop of the valve side sleeve pipe is grounded, and the fault risk is reduced.
Claims (5)
1. The utility model provides a converter transformer CT secondary circuit abnormal ground current detecting system which characterized in that: a phase, a phase and C phase of a secondary side winding of a valve side sleeve CT secondary winding (1) of the system are respectively connected with an A phase, a B phase and a C phase of a converter transformer body terminal box (2), the output ends of the A phase, the B phase and the C phase of the converter transformer body terminal box (2) are respectively connected with a converter transformer public terminal box (3), the output end of the converter transformer public terminal box (3) is connected with the input end of a converter transformer capacity protection (4), the public end output end of the converter transformer capacity protection (4) is connected with the public input end of the converter transformer public terminal box (3), the public input end of the converter transformer public terminal box (3) is further connected with a grounding copper bar (5) through a cable, a high-precision current pressure sensor (6) is installed on the cable at the grounding copper bar (5), and the high-precision current pressure sensor (6) is connected with a fault recording device (7).
2. The system for detecting abnormal ground current of the converter transformer CT secondary circuit according to claim 1, characterized in that: the grounding current of the high-precision current pressure sensor (6) is approximately 0A when no fault exists, and the short-time grounding current reaches 1A.
3. The system for detecting abnormal ground current of the converter transformer CT secondary circuit according to claim 1, characterized in that: the transformation ratio of the high-precision current pressure sensor (6) is 5/1A or 1/1A.
4. The system for detecting abnormal ground current of the converter transformer CT secondary circuit according to claim 1, characterized in that: the cable specification is 4 x 2.5 signal cable.
5. The system for detecting abnormal ground current of the converter transformer CT secondary circuit according to claim 1, characterized in that: the fault recorder (7) is a device capable of receiving real-time signals and processing images.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121423417.0U CN215415825U (en) | 2021-06-25 | 2021-06-25 | Converter transformer CT secondary circuit abnormal grounding current detection system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121423417.0U CN215415825U (en) | 2021-06-25 | 2021-06-25 | Converter transformer CT secondary circuit abnormal grounding current detection system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215415825U true CN215415825U (en) | 2022-01-04 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121423417.0U Active CN215415825U (en) | 2021-06-25 | 2021-06-25 | Converter transformer CT secondary circuit abnormal grounding current detection system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215415825U (en) |
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2021
- 2021-06-25 CN CN202121423417.0U patent/CN215415825U/en active Active
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