A fault correction device and method for a power cable cross-connection box

Abstract

The present invention relates to a fault correction device and method for a power cable cross-connection box, the device includes an inner core connection mechanism, an inner core electrode interconnection circuit, an outer core electrode interconnection circuit and an outer core connection mechanism connected in sequence, as well as a grounding switching circuit and a control mechanism, the phase sequence switching circuit is connected in series in a series branch; each phase input end of the inner core electrode interconnection circuit is respectively connected to two switches, one of which is connected to the output end of the corresponding phase, and the other of which is connected in series in sequence to form a loop; the input end of each phase of the outer core electrode interconnection circuit is directly connected to the output end, and each phase input end is also connected to a switch, and each switch is connected in series in sequence to form a loop. Compared with the prior art, the present invention realizes online correction of two types of faults including wrong connection of the transposition phase sequence and wrong connection of the inner and outer cores of the coaxial cable, and can effectively ensure the safety of the cable line and operators; it can be split into multiple sets of equipment to reduce the volume of the equipment and can be used arbitrarily according to the on-site environment.

Description

Technical Field

[0001] The invention relates to the field of power cable cross-connection boxes, and in particular to a fault correction device and method for a power cable cross-connection box. Background Art

[0002] like Figure 1 As shown, power cables, especially XLPE cables, are equipped with two cross-connection boxes in every three sections of power cable lines. The cross-connection between the sheaths of cables with different phase sequences is realized through the built-in transposition row. Correct and appropriate cross-connection transposition connection can effectively suppress the influence of sheath induced current and induced voltage, such as heating, insulation breakdown, etc. Figure 2 As shown in the figure, due to the quality of the project and other reasons, the cross-connection of the power cable sheath sometimes causes the wrong connection of the transposition row and the coaxial cable, mainly including the wrong phase sequence of the grounding wire and the coaxial cable, the wrong phase sequence of the transposition row and the wrong electrode swap of the inner and outer cores of the coaxial cable, which makes the induced electromotive force vector sum of the three-section cable sheath larger, thus forming a larger sheath current, causing heat loss and insulation degradation. There are other faults generated during operation, such as the theft of the transposition row, which will also have a certain impact on the cable system.

[0003] At present, the more conservative approach to dealing with the fault of power cable cross-connection is to stop the power supply of the cable line and then correct the transposition row, which has a greater impact on power users, especially for cable lines with higher voltage levels. In addition, during the power consumption valley period, under the condition of reliable safety protection measures, the transposition row can be disassembled for a short time to make the node out of the suspended state. At this time, the power consumption is small, and the induced voltage and current are also small, which usually does not cause obvious harm to the operator and the cable system. Unless in an emergency, this operation is generally not recommended. It can be seen that the difficulty of online correction of power cable cross-connection faults lies in the fact that the power supply current of the cable line is large, which makes the induced voltage and induced current of the sheath large. When removing and installing the transposition row, a large arc and overshoot voltage will be generated, which will cause great harm to the operator and the cable system itself.

[0004] The invention with publication number CN108957202A discloses an online correction method for a grounding box using a transition junction box, which is used to correct the two-phase transposition misconnection fault of the faulty junction box online, and specifically includes the following steps: 1) Detect whether the grounding box has a two-phase transposition wiring fault. If so, proceed to step 2), if not, return to step 1); 2) At the cable insulation joint of the faulty grounding box, three grounding wire coaxial cables on the transition junction box are respectively passed through the transition junction box and connected to the transition junction box. The wiring method of the transition junction box is consistent with the wiring method of the normal grounding box, that is, the default wiring method; 3) Disassemble the faulty grounding box online and correct its wiring method; 4) Connect the corrected grounding box to the grounding system online, and disassemble the transition junction box to complete the correction of the two-phase transposition wiring fault of the faulty junction box.

[0005] The online correction method of the grounding box can only handle the phase misconnection of the transposition row and the coaxial cable, but is not suitable for the misconnection of the inner and outer core electrodes of the coaxial cable. The control mechanism used in this scheme can only be applied to simple phase swap control and cannot realize complex control modes. This scheme uses a current limiting resistor as a measure to limit the generation of arcs. In actual use, the impedance of the connecting wire itself is sufficient to play a current limiting role. At the same time, the use of a contactor with high switching power can fully realize the operation of direct grounding without a transition state.

[0006] The invention with authorization announcement number CN104104029B discloses a multifunctional grounding device for a high-voltage cable that can monitor the load status, characterized in that: it includes a first protection circuit U1, a second protection circuit U2, air switches K7-K9 and wiring terminals P1~P6; the first protection circuit includes a protector R1-R3, a voltmeter V1-V3, an ammeter A1-A3, an air switch K1-K3 and wiring terminals P11~P13; the second protection circuit includes a protector R4-R6, a voltmeter V4-V6, an ammeter A4-A6, an air switch K4-K6 and wiring terminals P21~P23.

[0007] The device uses six switching switches to realize the online access mode and online fault correction of the direct grounding box and the cross-connection box, and uses the combination of switching switches and protective resistors to realize the functions of the direct grounding box and its protective resistor. This solution relies on manual wiring and exchanging the wiring phase sequence to realize the cross-connection mode of positive phase sequence and reverse phase sequence. It is completely manual operation based on the operator's experience, which is easy to cause secondary wiring errors. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a fault correction device and method for a power cable cross-connection box that can handle two types of faults: wrong connection of the phase sequence of the transposed arrangement and wrong connection of the inner and outer cores of the coaxial cable.

[0009] The purpose of the present invention can be achieved by the following technical solutions:

[0010] A fault correction device for a power cable cross-connection box, comprising an inner core connection mechanism, an outer core connection mechanism, a phase sequence switching circuit, a grounding switching circuit and a control mechanism, the fault correction device further comprising an inner core electrode interconnection circuit and an outer core electrode interconnection circuit, the inner core connection mechanism, the inner core electrode interconnection circuit, the outer core electrode interconnection circuit and the outer core connection mechanism are sequentially connected to form a series branch, the phase sequence switching circuit is connected in series in the series branch;

[0011] The A-phase input end of the inner core electrode interconnection circuit is respectively connected to the first A-phase switch and the second A-phase switch, the B-phase input end is respectively connected to the first B-phase switch and the second B-phase switch, and the C-phase input end is respectively connected to the first C-phase switch and the second C-phase switch, the first A-phase switch, the first B-phase switch and the first C-phase switch are sequentially connected in series to form a loop, and the second A-phase switch, the second B-phase switch and the second C-phase switch are respectively connected to the output ends of the corresponding phases;

[0012] The input end and output end of each phase of the outer core electrode interconnection circuit are directly connected, the A-phase input end of the outer core electrode interconnection circuit is also connected to the third A-phase switch, the B-phase input end is also connected to the third B-phase switch, and the C-phase input end is also connected to the third C-phase switch. The third A-phase switch, the third B-phase switch and the third C-phase switch are connected in series in sequence to form a loop.

[0013] Furthermore, the inner core electrode interconnection circuit, the phase sequence switching circuit and the outer core electrode interconnection circuit are connected in sequence; the input end of each phase of the phase sequence switching circuit is respectively connected to the output end of each phase of the inner core electrode interconnection circuit, and the output end of each phase of the phase sequence switching circuit is respectively connected to the input end of each phase of the outer core electrode interconnection circuit.

[0014] Furthermore, the inner core connection mechanism, the phase sequence switching circuit, the inner core electrode interconnection circuit and the outer core electrode interconnection circuit are connected in sequence; the output end of each phase of the inner core connection mechanism is respectively connected to the input end of each phase of the phase sequence switching circuit, and the output end of each phase of the phase sequence switching circuit is respectively connected to the input end of each phase of the inner core electrode interconnection circuit.

[0015] Furthermore, the phase sequence switching mechanism includes a positive phase sequence switch, a negative phase sequence switch, an inner core grounding switch and an outer core grounding switch.

[0016] The input end of the positive phase sequence switch is connected to the common input end of the phase sequence switching mechanism, and the output end of the positive phase sequence switch is connected to the common output end of the phase sequence switching mechanism through a positive phase sequence wiring line;

[0017] The input end of the reverse phase sequence switch is connected to the common input end of the phase sequence switch mechanism, and the output end of the reverse phase sequence switch is connected to the common output end of the phase sequence switch mechanism through a reverse phase sequence wiring line;

[0018] The input end of the inner core grounding switch is connected to the common input end of the phase sequence switching mechanism, and the output end of the inner core grounding switch is grounded;

[0019] The input end of the outer core grounding switch is grounded, and the output end of the outer core grounding switch is connected to the common output end of the phase sequence switching mechanism.

[0020] Furthermore, the positive phase sequence wiring circuit comprises:

[0021] The A-phase output terminal of the positive phase sequence switch is connected to the B-phase common output terminal of the phase sequence switching mechanism.

[0022] The B-phase output terminal of the positive phase sequence switch is connected to the C-phase common output terminal of the phase sequence switching mechanism.

[0023] The C-phase output terminal of the positive phase sequence switch is connected to the A-phase common output terminal of the phase sequence switching mechanism;

[0024] The reverse phase sequence wiring circuit comprises:

[0025] The A-phase output terminal of the reverse phase sequence switch is connected to the C-phase common output terminal of the phase sequence switching mechanism.

[0026] The B-phase output terminal of the reverse phase sequence switch is connected to the A-phase common output terminal of the phase sequence switching mechanism.

[0027] The C-phase output terminal of the reverse phase sequence switch is connected to the B-phase common output terminal of the phase sequence switching mechanism.

[0028] Furthermore, the positive phase sequence switch, the reverse phase sequence switch, the inner core grounding switch and the outer core grounding switch are all three-pole contactors with attached power-off delay relays.

[0029] Furthermore, the control mechanism includes a programmable controller and an intermediate relay group which are connected to each other, and the intermediate relay group is respectively connected to the inner core electrode interconnection circuit, the outer core electrode interconnection circuit and the phase sequence switching circuit.

[0030] Furthermore, the inner core connection mechanism includes a first A-phase clamp, a first B-phase clamp, a first C-phase clamp, a first inner core connection three-phase cable and a first three-phase terminal seat, and the first A-phase clamp, the first B-phase clamp and the first C-phase clamp are all connected to the inner core electrode of the cross-connection box at one end and connected to the live wire end of the first inner core connection three-phase cable at the other end, and the first inner core connection three-phase cable is connected to the first three-phase terminal seat.

[0031] Furthermore, the outer core connection mechanism includes a second A-phase clamp, a second B-phase clamp, a second C-phase clamp, a second inner core connection three-phase cable and a second three-phase terminal seat, and the second A-phase clamp, the second B-phase clamp and the second C-phase clamp are all connected to the inner core electrode of the cross-connection box at one end and connected to the live wire end of the second inner core connection three-phase cable at the other end, and the second inner core connection three-phase cable is connected to the second three-phase terminal seat.

[0032] The present invention also provides an online correction method using the fault correction device of the power cable cross-connection box as described above, comprising the following steps:

[0033] Step 1: Disconnect the power supply of the cross-connection repair device of the power cable, and the inside is in a floating state;

[0034] Step 2: The power cable cross-connection repair device is connected to the three inner core electrodes and the three outer core electrodes of the cross-connection box through two sets of three-phase cables, so that the cross-connection repair device and the original cross-connection box form a parallel access structure;

[0035] Step 3: The power cable cross-connection repair device is powered on, and the interior is in a floating state;

[0036] Step 4, switch to the direct grounding state, so that the inner and outer cores of the three-phase sheath grounded coaxial cable are in the grounding state;

[0037] Step 5: In the direct grounding state, remove the transposition bar of the original cross-connection box to make it in a floating state;

[0038] Step 6: Determine whether the fault type is a wrong phase sequence connection. If so, go to step 8; if not, go to step 7;

[0039] Step 7: Switch to the positive phase sequence and negative phase sequence respectively, observe and record the voltage and current conditions, determine and switch to the correct cross-interconnected phase sequence;

[0040] Step 8: Determine whether the fault type is that the inner and outer cores of the coaxial cable are connected incorrectly. If so, go to step 10; if not, go to step 9;

[0041] Step 9, by controlling the inner core electrode interconnection circuit and the outer core electrode interconnection circuit to switch to the inner and outer core interchanged state of the coaxial cable in phase A, the inner and outer core interchanged state of the coaxial cable in phase B, and the inner and outer core interchanged state of the coaxial cable in phase C, respectively, observing and recording the voltage and current conditions, judging and switching to the correct inner and outer core connection state of the coaxial cable;

[0042] Step 10: Install the transposition row of the original cross-connection box according to the correct phase sequence and the connection status of the inner and outer cores of the coaxial cable. Due to the equal potential during the installation process, no arc is generated;

[0043] Step 11: Under the equipotential state, remove the power cable cross-connection repair device and its connecting cables, and the process ends.

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] (1) The present invention leads the inner core and outer core lines from the cross-connection box through the inner core connection mechanism and the outer core connection mechanism, and can realize the switching of the inner and outer core electrodes of any coaxial cable through the inner core electrode interconnection circuit and the outer core electrode interconnection circuit composed of the switch; the switching of the positive phase sequence and the reverse phase sequence is realized through the phase sequence switching circuit; the function of the cross-connection box can be temporarily replaced, and other grounding system performance research and other experimental research can be carried out at the same time; the present invention realizes the online correction of the transposition row misconnection fault, including the transposition row phase sequence misconnection and the coaxial cable inner and outer core misconnection fault, and through the grounding switching circuit, the connection point is always kept in a non-floating state, effectively ensuring the safety of the cable line and the operator;

[0046] (2) The present invention can flexibly match and connect the phase sequence switching circuit, the inner core electrode interconnection circuit, and the outer core electrode interconnection circuit, and can be disassembled and combined to achieve miniaturization and convenience of the equipment.

[0047] (3) Easy to operate, and can be set up with an error correction function, which is not likely to damage equipment or personnel;

[0048] (4) Providing direct grounding to ensure the safety of operators and effectively suppress the generation of arcs;

[0049] (5) Use power-off delay relay to assist, so that the phase sequence switching process is always in a non-suspended state, further suppressing the generation of contact arc;

[0050] (6) After switching to the correct phase sequence, install the transposition bar under equipotential conditions without arcing. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a schematic diagram of a normal cross-connection structure in a cross-connection box;

[0052] Figure 2 This is a schematic diagram of the ground wire coaxial cable being connected in the wrong phase sequence;

[0053] Figure 3 This is a schematic diagram of the wrong phase sequence connection for the transposition arrangement;

[0054] Figure 4 This is a schematic diagram of the inner and outer core electrodes of the coaxial cable being swapped and connected incorrectly;

[0055] Figure 5 A schematic diagram of a connection structure of a fault correction device of a power cable cross-connection box in an embodiment of the present invention;

[0056] Figure 6 It is a block diagram of the composition of the inner core connection mechanism in an embodiment of the present invention;

[0057] Figure 7 is a block diagram of the composition of the outer core connection mechanism in an embodiment of the present invention;

[0058] Figure 8 is a block diagram of a phase sequence switching circuit in an embodiment of the present invention;

[0059] Fig. 9 is a block diagram of a phase sequence switching circuit in an embodiment of the present invention;

[0060] Fig.10 is a block diagram of the composition of the inner core electrode interconnection circuit in an embodiment of the present invention;

[0061] Fig.11 is a block diagram of the composition of the outer core electrode interconnection circuit in an embodiment of the present invention;

[0062] Fig.12 This is a schematic diagram of a first connection state of a fault correction device in an embodiment of the present invention;

[0063] Fig.13 This is a schematic diagram of a second connection state of the fault correction device in an embodiment of the present invention;

[0064] Fig.14 This is a schematic diagram of a third connection state of the fault correction device in an embodiment of the present invention;

[0065] Fig.15 Schematic diagram of a fourth connection state of the fault correction device in an embodiment of the present invention;

[0066] In the figure, 1, inner core connection mechanism, 2, outer core connection mechanism, 3, inner core electrode interconnection circuit, 301, A phase input terminal of the inner core electrode interconnection circuit, 302, B phase input terminal of the inner core electrode interconnection circuit, 303, C phase input terminal of the inner core electrode interconnection circuit, 304, first A phase switch, 305, second A phase switch, 306, first B phase switch, 307, second B phase switch, 308, first C phase switch, 309, second C phase switch, 310, A phase output terminal of the inner core electrode interconnection circuit, 311, B phase output terminal of the inner core electrode interconnection circuit, 312, C phase output terminal of the inner core electrode interconnection circuit, 4, outer core electrode interconnection circuit, 401, A phase input terminal of the outer core electrode interconnection circuit, 402, B phase input terminal of the outer core electrode interconnection circuit, 403, C phase input terminal of the outer core electrode interconnection circuit, 4 04. The third A-phase switch, 405. The third B-phase switch, 406. The third C-phase switch, 407. The A-phase output terminal of the outer core electrode interconnection circuit, 408. The B-phase output terminal of the outer core electrode interconnection circuit, 409. The C-phase output terminal of the outer core electrode interconnection circuit, 5. Phase sequence switching circuit, 501. The A-phase input terminal of the phase sequence switching circuit, 502. The B-phase input terminal of the phase sequence switching circuit, 503. The C-phase input terminal of the phase sequence switching circuit, 504. Positive phase sequence switch, 505. Reverse phase sequence switch, 506. Inner core grounding switch, 507. Outer core grounding switch, 508. The A-phase output terminal of the phase sequence switching circuit, 509. The B-phase output terminal of the phase sequence switching circuit, 510. The C-phase output terminal of the phase sequence switching circuit, 6. Grounding switching circuit, 7. Control mechanism, 701. Programmable controller, 702. Intermediate relay group. DETAILED DESCRIPTION

[0067] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0068] Example 1

[0069] This embodiment provides a fault correction device for a power cable cross-connection box, comprising an inner core connection mechanism 1, an outer core connection mechanism 2, an inner core electrode interconnection circuit 3, an outer core electrode interconnection circuit 4, a phase sequence switching circuit 5, a grounding switching circuit 6 and a control mechanism 7, wherein the inner core connection mechanism 1, the inner core electrode interconnection circuit 3, the outer core electrode interconnection circuit 4 and the outer core connection mechanism 2 are connected in sequence to form a series branch, and the phase sequence switching circuit 5 is connected in series in the series branch;

[0070] The A-phase input terminal 301 of the inner core electrode interconnection circuit 3 is respectively connected to the first A-phase switch 304 and the second A-phase switch 305, the B-phase input terminal 302 is respectively connected to the first B-phase switch 306 and the second B-phase switch 307, and the C-phase input terminal 303 is respectively connected to the first C-phase switch 308 and the second C-phase switch 309. The first A-phase switch 304, the first B-phase switch 306 and the first C-phase switch 308 are sequentially connected in series to form a loop, and the second A-phase switch 305, the second B-phase switch 307 and the second C-phase switch 309 are respectively connected to the output terminals of the corresponding phases;

[0071] The input end and output end of each phase of the outer core electrode interconnection circuit 4 are directly connected. The A-phase input end 401 of the outer core electrode interconnection circuit 4 is also connected to the third A-phase switch 404, the B-phase input end 402 is also connected to the third B-phase switch 405, and the C-phase input end 403 is also connected to the third C-phase switch 406. The third A-phase switch, the third B-phase switch 405 and the third C-phase switch 406 are connected in series in sequence to form a loop.

[0072] The inner core connecting mechanism 1 is used to connect the inner core electrode 91 of the cross-connection box 9; the outer core connecting mechanism 2 is used to connect the outer core electrode 92 of the cross-connection box 9; the phase sequence switching circuit 5 is used to switch between the three phase sequence states of positive phase sequence, reverse phase sequence and direct grounding; the inner core connecting mechanism 1, the outer core connecting mechanism 2, the inner core electrode interconnection circuit 3, the outer core electrode interconnection circuit 4, and the phase sequence switching circuit 5 are connected in series; the connection positions of the inner core electrode interconnection circuit 3, the outer core electrode interconnection circuit 4, and the phase sequence switching circuit 5 are interchangeable; the connection positions of the inner core connecting mechanism 1 and the outer core connecting mechanism 2 are interchangeable; the phase sequence switching circuit 5 is connected to the ground potential through the grounding electrode 8; the control mechanism 7 controls the connection state of the entire device.

[0073] As a preferred embodiment, the inner core electrode interconnection circuit 3, the phase sequence switching circuit 5 and the outer core electrode interconnection circuit 4 are connected in sequence; the input end of each phase of the phase sequence switching circuit 5 is respectively connected to the output end of each phase of the inner core electrode interconnection circuit 3, and the output end of each phase of the phase sequence switching circuit 5 is respectively connected to the input end of each phase of the outer core electrode interconnection circuit 4.

[0074] This embodiment cites three implementation processes:

[0075] When the inner and outer core electrodes of the A phase coaxial cable are swapped and connected incorrectly, but the copper plates are in the correct phase sequence, the cross-connection state will be as follows: Figure 8 As shown in the figure on the right, the correct correction method is to, in the case of power failure, only in the cross-connection box, follow Figure 8 Therefore, the inner core electrode interconnection circuit 3 and the outer core electrode interconnection circuit 4 are required to realize Figure 8 Connection status on the right.

[0076] Specifically, the first C-phase switch 308 is closed, the third A-phase switch 404 is closed, the second B-phase switch 307 is closed, and the other switches are disconnected, and the phase sequence switching circuit 5 is switched to the correct phase sequence state, so that the connection state is presented. Figure 8 Connection status on the right.

[0077] like Fig. 9 As shown, similarly, when the inner and outer core electrodes of the B-phase coaxial cable are swapped and connected incorrectly, but the copper plate phase sequence is correct, the correction method is to close the first A-phase switch 304, the third B-phase switch 405, the second C-phase switch 309, and the other switches are disconnected, and the phase sequence switching circuit 5 is switched to the correct phase sequence state, so that the connection state can be presented Fig. 9 Connection status on the right.

[0078] like Fig.10 As shown, similarly, when the inner and outer core electrodes of the C phase coaxial cable are swapped and connected incorrectly, but the copper plate phase sequence is correct, the correction method is to close the second A phase switch 305, the first B phase switch 306, the third A phase switch 404, and the other switches are disconnected, and the phase sequence switching circuit 5 is switched to the correct phase sequence state, so that the connection state can be presented Fig.10 Connection status on the right.

[0079] As a preferred embodiment, the inner core connecting mechanism 1, the phase sequence switching circuit 5, the inner core electrode interconnection circuit 3 and the outer core electrode interconnection circuit 4 are connected in sequence; the output ends of each phase of the inner core connecting mechanism 1 are respectively connected to the input ends of each phase of the phase sequence switching circuit 5, and the output ends of each phase of the phase sequence switching circuit 5 are respectively connected to the input ends of each phase of the inner core electrode interconnection circuit 3.

[0080] like Fig.11 As shown, the phase sequence switching circuit 5, the inner core electrode interconnection circuit 3 and the outer core electrode interconnection circuit 4 are used in series. When the inner and outer core electrodes of the A-phase coaxial cable are wrongly connected, but the copper plate phase sequence is correct, the correction method is to close the first A-phase switch 304, the second C-phase switch 309, the third A-phase switch 404, and the other switches are disconnected, and the phase sequence switching circuit 5 is switched to the correct phase sequence state, so that the connection state is presented. Fig.11 Connection status on the right.

[0081] Similarly, other series connection sequences of the phase sequence switching circuit 5, the inner core electrode interconnection circuit 3 and the outer core electrode interconnection circuit 4 correspond to corresponding control and switching methods. They only need to be written into the control mechanism 7 according to the predetermined sequence and the corresponding switch state of the switch to achieve a flexible combination method.

[0082] As a preferred embodiment, the phase sequence switching mechanism 5 includes a positive phase sequence switch 504, a negative phase sequence switch 505, an inner core grounding switch 506 and an outer core grounding switch 507.

[0083] The input end of the positive phase sequence switch 504 is connected to the common input end of the phase sequence switch mechanism 5, and the output end of the positive phase sequence switch 504 is connected to the common output end of the phase sequence switch mechanism 5 through a positive phase sequence wiring line;

[0084] The input end of the reverse phase sequence switch 505 is connected to the common input end of the phase sequence switch mechanism 5, and the output end of the reverse phase sequence switch 505 is connected to the common output end of the phase sequence switch mechanism 5 through a reverse phase sequence wiring line;

[0085] The input end of the inner core grounding switch 506 is connected to the common input end of the phase sequence switching mechanism 5, and the output end of the inner core grounding switch 506 is grounded;

[0086] An input end of the outer core grounding switch 507 is grounded, and an output end of the outer core grounding switch 507 is connected to a common output end of the phase sequence switching mechanism 5 .

[0087] As a preferred implementation, the positive phase sequence wiring circuit includes:

[0088] The A-phase output terminal of the positive phase sequence switch 504 is connected to the B-phase common output terminal of the phase sequence switching mechanism 5.

[0089] The B-phase output terminal of the positive phase sequence switch 504 is connected to the C-phase common output terminal of the phase sequence switch mechanism 5, and the C-phase output terminal of the positive phase sequence switch 504 is connected to the A-phase common output terminal of the phase sequence switch mechanism 5;

[0090] The reverse phase sequence wiring circuit includes:

[0091] The A-phase output terminal of the reverse phase sequence switch 505 is connected to the C-phase common output terminal of the phase sequence switching mechanism 5.

[0092] The B-phase output terminal of the reverse phase sequence switch 505 is connected to the A-phase common output terminal of the phase sequence switching mechanism 5.

[0093] The C-phase output terminal of the reverse phase sequence switch 505 is connected to the B-phase common output terminal of the phase sequence switching mechanism 5 .

[0094] As a preferred implementation, the positive phase sequence switch 504, the negative phase sequence switch 505, the inner core grounding switch 506 and the outer core grounding switch 507 are all three-pole contactors with attached power-off delay relays.

[0095] In this embodiment, the model of the three-pole contactor is CKJ5-400A / 1140V, the model of the attached power-off delay relay is LADR0, and the power-off delay is set to 0.5 seconds.

[0096] As a preferred embodiment, the control mechanism 7 includes a programmable controller 701 and an intermediate relay group 702 which are connected to each other. The intermediate relay group 702 is respectively connected to the inner core electrode interconnection circuit 3, the outer core electrode interconnection circuit 4 and the phase sequence switching circuit 5.

[0097] As a preferred embodiment, the inner core connecting mechanism 1 includes a first A phase clamp 101, a first B phase clamp 102, a first C phase clamp 103, a first inner core connected three-phase cable 104 and a first three-phase terminal seat 105. The first A phase clamp 101, the first B phase clamp 102 and the first C phase clamp 103 are all connected to the inner core electrode 91 of the cross-connection box 9 at one end and connected to the live wire end of the first inner core connected three-phase cable 104 at the other end. The first inner core connected three-phase cable 104 is connected to the first three-phase terminal seat 105.

[0098] As a preferred embodiment, the outer core connecting mechanism 2 includes a second A phase clamp 201, a second B phase clamp 202, a second C phase clamp 203, a second inner core connecting three-phase cable 204 and a second three-phase terminal seat 205. The second A phase clamp 201, the second B phase clamp 202 and the second C phase clamp 203 are all connected to the inner core electrode 92 of the cross-connection box 9 at one end, and connected to the live wire end of the second inner core connecting three-phase cable 204 at the other end. The second inner core connecting three-phase cable 204 is connected to the second three-phase terminal seat 205.

[0099] The principle of the method of using the correction device of the present invention is: a power cable cross-interconnection repair device is used to connect the original cross-interconnection box 9 in parallel to the cross-interconnection system of the power cable, and the induced voltage of the transposition row of the interconnection box is greatly reduced by switching to the direct grounding state to protect the operator. At the same time, the induced current is mainly passed through the temporarily connected power cable cross-interconnection repair device, forming a short-circuit effect on the transposition row, effectively reducing the arc when the transposition row is disassembled, and after replacing the original cross-interconnection box 9, the positive phase sequence, reverse phase sequence, and inner and outer core electrodes of the coaxial cable can be switched to restore the interconnection system to the correct cross-interconnection state, so that the transposition row installation is in an equipotential state and the arc is eliminated.

[0100] This embodiment also provides an online correction method using the fault correction device of the power cable cross-connection box as described above, comprising the following steps:

[0101] Step 1: Disconnect the power supply of the cross-connection repair device of the power cable, and the inside is in a floating state;

[0102] Step 2: The power cable cross-connection repair device is connected to the three inner core electrodes and the three outer core electrodes of the cross-connection box through two sets of three-phase cables, so that the cross-connection repair device and the original cross-connection box form a parallel access structure;

[0103] Step 3: The power cable cross-connection repair device is powered on, and the interior is in a floating state;

[0104] Step 4, switch to the direct grounding state, so that the inner and outer cores of the three-phase sheath grounded coaxial cable are in the grounding state;

[0105] Step 5: In the direct grounding state, remove the transposition bar of the original cross-connection box to make it in a floating state;

[0106] Step 6: Determine whether the fault type is a wrong phase sequence connection. If so, go to step 8; if not, go to step 7;

[0107] Step 7: Switch to the positive phase sequence and negative phase sequence respectively, observe and record the voltage and current conditions, determine and switch to the correct cross-interconnected phase sequence;

[0108] Step 8: Determine whether the fault type is that the inner and outer cores of the coaxial cable are connected incorrectly. If so, go to step 10; if not, go to step 9;

[0109] Step 9, by controlling the inner core electrode interconnection circuit and the outer core electrode interconnection circuit to switch to the inner and outer core interchanged state of the coaxial cable in phase A, the inner and outer core interchanged state of the coaxial cable in phase B, and the inner and outer core interchanged state of the coaxial cable in phase C, respectively, observing and recording the voltage and current conditions, judging and switching to the correct inner and outer core connection state of the coaxial cable;

[0110] Step 10: Install the transposition row of the original cross-connection box according to the correct phase sequence and the connection status of the inner and outer cores of the coaxial cable. Due to the equal potential during the installation process, no arc is generated;

[0111] Step 11: Under the equipotential state, remove the power cable cross-connection repair device and its connecting cables, and the process ends.

[0112] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A fault correction device for a power cable cross-connection box, comprising an inner core connection mechanism (1), an outer core connection mechanism (2), a phase sequence switching circuit (5), a grounding switching circuit (6) and a control mechanism (7), characterized in that: The fault correction device further comprises an inner core electrode interconnection circuit (3) and an outer core electrode interconnection circuit (4), wherein the inner core connection mechanism (1), the inner core electrode interconnection circuit (3), the outer core electrode interconnection circuit (4) and the outer core connection mechanism (2) are connected in sequence to form a series branch, and the phase sequence switching circuit (5) is connected in series in the series branch; The A-phase input end (301) of the inner core electrode interconnection circuit (3) is respectively connected to the first A-phase switch (304) and the second A-phase switch (305), the B-phase input end (302) is respectively connected to the first B-phase switch (306) and the second B-phase switch (307), and the C-phase input end (303) is respectively connected to the first C-phase switch (308) and the second C-phase switch (309), the first A-phase switch (304), the first B-phase switch (306) and the first C-phase switch (308) are sequentially connected in series to form a loop, and the second A-phase switch (305), the second B-phase switch (307) and the second C-phase switch (309) are respectively connected to the output ends of the corresponding phases; The input end and output end of each phase of the outer core electrode interconnection circuit (4) are directly connected, the A phase input end (401) of the outer core electrode interconnection circuit (4) is also connected to a third A phase switch (404), the B phase input end (402) is also connected to a third B phase switch (405), and the C phase input end (403) is also connected to a third C phase switch (406), and the third A phase switch (404), the third B phase switch (405) and the third C phase switch (406) are connected in series in sequence to form a loop; The phase sequence switching circuit (5) comprises a positive phase sequence switch (504), a negative phase sequence switch (505), an inner core grounding switch (506) and an outer core grounding switch (507). The input end of the positive phase sequence switch (504) is connected to the common input end of the phase sequence switching circuit (5), and the output end of the positive phase sequence switch (504) is connected to the common output end of the phase sequence switching circuit (5) via a positive phase sequence wiring line; The input end of the reverse phase sequence switch (505) is connected to the common input end of the phase sequence switching circuit (5), and the output end of the reverse phase sequence switch (505) is connected to the common output end of the phase sequence switching circuit (5) via a reverse phase sequence wiring line; The input end of the inner core grounding switch (506) is connected to the common input end of the phase sequence switching circuit (5), and the output end of the inner core grounding switch (506) is grounded; The output end of the outer core grounding switch (507) is grounded, and the input end of the outer core grounding switch (507) is connected to the common output end of the phase sequence switching circuit (5); The positive phase sequence wiring circuit comprises: The A-phase output terminal of the positive phase sequence switch (504) is connected to the B-phase common output terminal of the phase sequence switching circuit (5), The B-phase output terminal of the positive phase sequence switch (504) is connected to the C-phase common output terminal of the phase sequence switching circuit (5). The C-phase output terminal of the positive phase sequence switch (504) is connected to the A-phase common output terminal of the phase sequence switching circuit (5); The reverse phase sequence wiring circuit comprises: The A-phase output terminal of the reverse phase sequence switch (505) is connected to the C-phase common output terminal of the phase sequence switching circuit (5). The B-phase output terminal of the reverse phase sequence switch (505) is connected to the A-phase common output terminal of the phase sequence switching circuit (5), The C-phase output terminal of the reverse phase sequence switch (505) is connected to the B-phase common output terminal of the phase sequence switching circuit (5).

2. The fault correction device for a power cable cross-connection box according to claim 1, characterized in that: The inner core electrode interconnection circuit (3), the phase sequence switching circuit (5) and the outer core electrode interconnection circuit (4) are connected in sequence; the input end of each phase of the phase sequence switching circuit (5) is respectively connected to the output end of each phase of the inner core electrode interconnection circuit (3), and the output end of each phase of the phase sequence switching circuit (5) is respectively connected to the input end of each phase of the outer core electrode interconnection circuit (4).

3. The fault correction device for a power cable cross-connection box according to claim 1, characterized in that: The inner core connection mechanism (1), the phase sequence switching circuit (5), the inner core electrode interconnection circuit (3) and the outer core electrode interconnection circuit (4) are connected in sequence; the output end of each phase of the inner core connection mechanism (1) is respectively connected to the input end of each phase of the phase sequence switching circuit (5), and the output end of each phase of the phase sequence switching circuit (5) is respectively connected to the input end of each phase of the inner core electrode interconnection circuit (3).

4. The fault correction device for a power cable cross-connection box according to claim 1, characterized in that: The positive phase sequence switch (504), the negative phase sequence switch (505), the inner core grounding switch (506) and the outer core grounding switch (507) are all three-pole contactors with power-off delay relays.

5. The fault correction device for a power cable cross-connection box according to claim 1, characterized in that: The control mechanism (7) comprises a programmable controller (701) and an intermediate relay group (702) which are connected to each other. The intermediate relay group (702) is respectively connected to the inner core electrode interconnection circuit (3), the outer core electrode interconnection circuit (4) and the phase sequence switching circuit (5).

6. The fault correction device for a power cable cross-connection box according to claim 1, characterized in that: The inner core connection mechanism (1) comprises a first A-phase clamp (101), a first B-phase clamp (102), a first C-phase clamp (103), a first inner core connection three-phase cable (104) and a first three-phase terminal seat (105); the first A-phase clamp (101), the first B-phase clamp (102) and the first C-phase clamp (103) are all connected to the inner core electrode (91) of the cross-connection box (9) at one end and connected to the live wire end of the first inner core connection three-phase cable (104) at the other end; the first inner core connection three-phase cable (104) is connected to the first three-phase terminal seat (105).

7. The fault correction device for a power cable cross-connection box according to claim 1, characterized in that: The outer core connection mechanism (2) comprises a second A-phase clamp (201), a second B-phase clamp (202), a second C-phase clamp (203), a second inner core connection three-phase cable (204) and a second three-phase terminal seat (205); the second A-phase clamp (201), the second B-phase clamp (202) and the second C-phase clamp (203) are all connected to the outer core electrode (92) of the cross-connection box (9) at one end and connected to the live wire end of the second inner core connection three-phase cable (204) at the other end; the second inner core connection three-phase cable (204) is connected to the second three-phase terminal seat (205).

8. An online correction method using the fault correction device of a power cable cross-connection box as claimed in claim 1, characterized in that: The following steps are involved: Step 1: Disconnect the power supply of the power cable cross-connection correction device, and the inside is in a floating state; Step 2: The power cable cross-connection correction device is connected to three inner core electrodes and three outer core electrodes of the cross-connection box through two sets of three-phase cables, so that the cross-connection correction device and the original cross-connection box form a parallel access structure; Step 3: The power cable cross-connection correction device is powered on, and the inside is in a floating state; Step 4: Switch to the direct grounding state to make the inner and outer cores of the three-phase sheath grounded coaxial cable in the grounding state; Step 5: In the direct grounding state, remove the transposition bar of the original cross-connection box to make it in a floating state; Step 6: Determine whether the fault type is a wrong phase sequence connection. If so, go to step 8; if not, go to step 7; Step 7: Switch to the positive phase sequence and negative phase sequence respectively, observe and record the voltage and current conditions, determine and switch to the correct cross-interconnected phase sequence; Step 8: Determine whether the fault type is that the inner and outer cores of the coaxial cable are connected incorrectly. If so, go to step 10; if not, go to step 9; Step 9, by controlling the inner core electrode interconnection circuit and the outer core electrode interconnection circuit to switch to the inner and outer core interchanged state of the coaxial cable in phase A, the inner and outer core interchanged state of the coaxial cable in phase B, and the inner and outer core interchanged state of the coaxial cable in phase C, respectively, observing and recording the voltage and current conditions, judging and switching to the correct inner and outer core connection state of the coaxial cable; Step 10: Install the transposition row of the original cross-connection box according to the correct phase sequence and the connection status of the inner and outer cores of the coaxial cable. Due to the equal potential during the installation process, no arc is generated; Step 11: Under the equipotential state, remove the power cable cross-connection correction device and its connecting cables, and the process ends.

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