Rapid recovery device for cable coaxial structure at high-voltage cable crossing interconnection system

Abstract

The utility model belongs to the technical field of electric power engineering, and discloses a cable coaxial structure rapid recovery device at a high-voltage cable cross interconnection system, which comprises switching units respectively connected with three-phase cable shielding layers of a high-voltage cable, and a lightning arrester and a grounding terminal which are connected with the switching units, for any phase cable of the high-voltage cable, a first wiring terminal and a second wiring terminal of the switching unit corresponding to the phase cable are respectively connected with a coaxial line led out of a cable shielding layer in front of a crossing interconnection position of three-phase cable shielding layers in the phase cable and a coaxial line led out of a cable shielding layer behind the crossing interconnection position of the three-phase cable shielding layers in the phase cable. And the third wiring terminal is connected into a coaxial line led out from a cable shielding layer in front of a crossed interconnection part of three-phase cable shielding layers in another phase cable which is crosslinked with the phase cable. According to the utility model, the switching of the coaxial or cross interconnection mode of each phase cable can be realized, so that the coaxial structure at the cross interconnection part of the high-voltage cable can be quickly recovered.

Description

Technical Field

[0001] The utility model belongs to the technical field of power engineering, relates to a high-voltage cable detection device, and particularly relates to a device for quickly restoring the coaxial structure of a cable at a high-voltage cable cross-bonding system. Background Art

[0002] The broadband impedance analysis technology based on frequency-domain parameter measurement has been widely applied to cable condition detection and achieved good application effects in medium- and low-voltage cable systems.

[0003] However, when applying the broadband impedance analysis technology to high-voltage cable defect detection, there are still problems of low accuracy rate and high misdiagnosis rate. A core reason for this problem is that the high-voltage cable cross-bonding system destroys the coaxial structure of the high-voltage cable, causing a sudden change in the characteristic impedance at the cross-bonding of the high-voltage cable, and further leading to a change in the propagation path of the electromagnetic wave for broadband impedance measurement, ultimately resulting in large impedance measurement noise, many interferences, and inaccuracies.

[0004] In addition, high-voltage cables are long and have many cross-bonding segments. Limited by the power grid power outage time, traditional manual methods cannot restore the coaxial structure of the entire cross-bonding segment within a limited time. Therefore, how to quickly restore the coaxial structure of the high-voltage cable at the cross-bonding of the high-voltage cable in broadband impedance testing is the problem to be solved by the utility model. Summary of the Utility Model

[0005] The purpose of the utility model aims at the problems existing in the above-mentioned prior art, provides a device for quickly restoring the coaxial structure of a cable at a high-voltage cable cross-bonding system, and can quickly restore the coaxial structure at the cross-bonding of the high-voltage cable by setting a switching unit connected to three phases of the high-voltage cable.

[0006] To achieve the above purpose, the utility model adopts the following technical solutions.

[0007] The utility model provides a device for quickly restoring the coaxial structure of a cable at a high-voltage cable cross-bonding system, which includes a switching unit respectively connected to the three-phase cable shields of the high-voltage cable, and a lightning arrester and a grounding terminal connected to each switching unit; each switching unit has the same structure;

[0008] The switching unit includes a first wiring terminal, a second wiring terminal, a third wiring terminal, a fourth wiring terminal, and a single-pole double-throw switch; the single-pole double-throw switch includes a moving contact, a first static contact, and a second static contact, the first static contact is connected to the first wiring terminal, the moving contact is connected to the second wiring terminal, and the second static contact and the third wiring terminal are both connected to the fourth wiring terminal; the fourth wiring terminal is sequentially connected to the corresponding lightning arrester and grounding terminal;

[0009] For any one phase of the high-voltage cable, the first terminal and the second terminal of the corresponding switching unit are respectively connected to the coaxial cable led out from the cable shield before the cross-interconnection of the three-phase cable shields of this phase of the cable and the coaxial cable led out from the cable shield after the cross-interconnection of the three-phase cable shields of this phase of the cable, and the third terminal is connected to the coaxial cable led out from the cable shield before the cross-interconnection of the three-phase cable shields of the other phase of the cable cross-linked with this phase of the cable.

[0010] In one implementable manner, the single-pole double-throw switch is a single-pole double-throw relay.

[0011] Furthermore, the single-pole double-throw relay is controlled by a control circuit.

[0012] In one implementable manner, the control circuit includes a controller, a current-limiting resistor, a protection resistor, a field-effect transistor, a freewheeling diode, and a DC power supply; the controller is connected to the gate of the field-effect transistor via the protection resistor, the DC power supply, the coil of the single-pole double-throw relay, and the current-limiting resistor are connected in series and then connected to the drain of the field-effect transistor, the freewheeling diode is connected in parallel across the coil of the single-pole double-throw relay, and the source of the field-effect transistor is grounded. Furthermore, the gate of the field-effect transistor is also grounded via a discharging resistor.

[0013] In one implementable manner, the controller is a microcontroller such as STM32F103ZET6 or DSPIC33FJ64GS606.

[0014] In one implementable manner, the cable coaxial structure rapid recovery device at the cross-interconnection system of the high-voltage cable further includes a cross-interconnection box; the cross-interconnection part of the three-phase cable shields of the high-voltage cable, the switching unit, the lightning arrester, the grounding terminal, and the control circuit are installed in the cross-interconnection box.

[0015] Compared with the prior art, the cable coaxial structure rapid recovery device at the cross-interconnection system of the high-voltage cable provided by the present utility model has the following beneficial effects:

[0016] (1) The present utility model sets a switching unit in each phase of the high-voltage cable, and the three terminals of the switching unit are respectively connected to the coaxial cables at the cross-interconnection of the cable shields of the two cross-linked phases, so as to realize the switching between the coaxial or cross-interconnection modes of each phase of the cable, and thus can realize the rapid recovery of the coaxial structure at the cross-interconnection of the high-voltage cable;

[0017] (2) The switching unit in the present utility model is provided with a single-pole double-throw relay, and the automatic control of the single-pole double-throw relay is realized through the designed control circuit, thereby effectively ensuring the rapid switching between the coaxial or cross-interconnection modes of each phase of the cable;

[0018] (3) In the present utility model, the switching unit is also connected with a lightning arrester and a grounding terminal, which can ensure that the residual energy is quickly discharged after the lightning arrester operates, maintain the potential balance of the metal sheath, prevent insulation damage, and also ensure the electromagnetic compatibility of the coaxial structure and avoid signal interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of a device for quickly restoring the coaxial structure of a high-voltage cable cross-connected system provided by an embodiment of the present utility model;

[0020] Figure 2 It is an internal wiring diagram of the switching unit;

[0021] Figure 3 It is a schematic structural diagram of the control circuit;

[0022] In the figure, 1 - cross-connection box;

[0023] L 1 - Phase A cable; L 2 - Phase B cable; L 3 - Phase C cable;

[0024] L 1,1 - The coaxial cable led out from the cable shield before the cross-connection of the three-phase cable shields in the Phase A cable; L 1,2 - The coaxial cable led out from the cable shield after the cross-connection of the three-phase cable shields in the Phase A cable;

[0025] L 2,1 - The coaxial cable led out from the cable shield before the cross-connection of the three-phase cable shields in the Phase B cable; L 2,2 - The coaxial cable led out from the cable shield after the cross-connection of the three-phase cable shields in the Phase B cable;

[0026] L 3,1 - The coaxial cable led out from the cable shield before the cross-connection of the three-phase cable shields in the Phase C cable; L 3,2 - The coaxial cable led out from the cable shield after the cross-connection of the three-phase cable shields in the Phase C cable;

[0027] S 1 - First switching unit; S 2 - Second switching unit; S 3 - Third switching unit;

[0028] A 1 - First lightning arrester; A 2 - Second lightning arrester;A 3 - Third lightning arrester;

[0029] G 1 - First grounding terminal; G 2 - Second grounding terminal; G 3 - Third grounding terminal;

[0030] T 1 - First wiring terminal; T 2 - Second wiring terminal; T 3 - Third wiring terminal; T 4 - Fourth wiring terminal;

[0031] P 1 - First static contact; P 2 - Moving contact; P 3 - Second static contact;

[0032] VCC - DC power supply; L - Coil; D - Freewheeling diode; M - Field - effect transistor; R 1 - Current - limiting resistor; R 2 - Protection resistor; R 3 - Bleeder resistor. Detailed implementation manners

[0033] The technical solutions of each embodiment of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts belong to the scope protected by the present utility model.

[0034] Embodiment

[0035] As Figure 1 shown, the three - phase cables of the high - voltage cable are respectively the A - phase cable L 1, the B - phase cable L 2, and the C - phase cable L 3. The cable coaxial structure rapid recovery device at the high - voltage cable cross - bonding system provided in this embodiment includes a first switching unit L 1 connected to the shielding layer of the A - phase cable S 1, a second switching unit L 2 connected to the shielding layer of the B - phase cable S 2, a third switching unit L 3 connected to the shielding layer of the C - phase cable S 3, and a first lightning arrester S 1 connected to the first switching unit A1. The first grounding terminal G 1. The second lightning arrester connected to the second switching unit S 2 A 2. The second grounding terminal G 2. The third lightning arrester connected to the third switching unit S 3 A 3. The third grounding terminal G 3

[0036] The first switching unit S 1. The second switching unit S 2. The third switching unit S 3 have the same structure. As Figure 2 shown, the switching unit includes a first connection terminal T 1, a second connection terminal T 2, a third connection terminal T 3, a fourth connection terminal T 4 and a single-pole double-throw switch. Here, the single-pole double-throw switch uses a single-pole double-throw relay, and the model is such as JQC-3FF-S-Z

[0037] The single-pole double-throw relay includes a moving contact P 2, a first stationary contact P 1 and a second stationary contact P 3. The first stationary contact P 1 is connected to the first connection terminal T 1, the moving contact P 2 is connected to the second connection terminal T 2, and the second stationary contact P 3 is connected to the third connection terminal T 3 and simultaneously connected to the fourth connection terminal T 4. The fourth connection terminal T 4 is sequentially connected to the corresponding lightning arresters and grounding terminals of each switching unit

[0038] In this embodiment, for the A-phase cable L 1, the cable cross-linked with it is the C-phase cable L 3. The first connection terminal S 1 and the second connection terminal T 1 of the first switching unit T 2 are respectively connected to the coaxial cables led out from the cable shield before the cross-interconnection of the three-phase cable shields in the A-phase cable L 1,1 and the coaxial cable led out from the cable shield after the cross-interconnection of the three-phase cable shields in the A-phase cable L 1,2 The third connection terminal T 3 is connected to the cable cross-linked with the A-phase cable L1. The coaxial cable led out from the cable shield before the cross-interconnection of the three-phase cable shields in the cross-linked C-phase cable L 3,1 . The first switching unit S The fourth terminal of 1 T 4 is sequentially connected to the first lightning arrester A 1 and the first grounding terminal G 1.

[0039] For the B-phase cable L 2, the cable cross-linked with it is the A-phase cable L 1. The second switching unit S The first terminal of 2 T 1 and the second terminal T 2 are respectively connected to the coaxial cable led out from the cable shield before the cross-interconnection of the three-phase cable shields in the B-phase cable L 2,1 and the coaxial cable led out from the cable shield after the cross-interconnection of the three-phase cable shields in the B-phase cable L 2,2 , the third terminal T 3 is connected to the coaxial cable led out from the cable shield before the cross-interconnection of the three-phase cable shields in the A-phase cable cross-linked with the B-phase cable L 2 L 1,1 . The second switching unit S The fourth terminal of 2 T 4 is sequentially connected to the second lightning arrester A 2 and the second grounding terminal G 2.

[0040] For the C-phase cable L 3, the cable cross-linked with it is the B-phase cable L 2. The third switching unit S The first terminal of 3 T 1 and the second terminal T 2 are respectively connected to the coaxial cable led out from the cable shield before the cross-interconnection of the three-phase cable shields in the C-phase cable L 3,1 and the coaxial cable led out from the cable shield after the cross-interconnection of the three-phase cable shields in the C-phase cable L 3,2 , the third terminal T 3 is connected to the coaxial cable led out from the cable shield before the cross-interconnection of the three-phase cable shields in the B-phase cable cross-linked with the C-phase cable L 3 L 2,1 . The third switching unit S The fourth terminal of 3 T 4 is connected to the third lightning arresterA 3 and the third grounding terminal G 3 are connected in sequence.

[0041] The single-pole double-throw relay is controlled by a control circuit. As Figure 3 shown, the control circuit includes a controller, a current-limiting resistor R 1, a protection resistor R 2, a discharge resistor R 3, a field-effect transistor M , a freewheeling diode D and a DC power supply VCC. The controller is connected to the gate of the field-effect transistor R 2 via the protection resistor M . The DC power supply VCC, the coil of the single-pole double-throw relay L , the current-limiting resistor R 1 are connected in series and then connected to the drain of the field-effect transistor M . The freewheeling diode D is connected in parallel across the coil of the single-pole double-throw relay L . The source of the field-effect transistor M is grounded, and the gate of the field-effect transistor M is also grounded via the discharge resistor R 3.

[0042] In this embodiment, the controller used is STM32F103ZET6. The control circuits of the single-pole double-throw relays of each switching unit are connected to the corresponding output pins of the controller, and the actions of each single-pole double-throw relay are controlled by this controller; the controller is connected to a computer terminal (such as Lenovo Yangtian M4000Q) or a handheld terminal (such as Redmi Pad SE) through a wireless network to receive the switching instruction signals for controlling the single-pole double-throw relays of each switching unit. The current-limiting resistor R 1 is used to protect the field-effect transistor M and control the coil of the single-pole double-throw relay to avoid overcurrent, and its value is 20~100 ohms. The protection resistor R 2 is used to limit the gate current of the field-effect transistor M and provide protection, and its value is 5~20 ohms. The discharge resistor R 3 is used to provide a release path for the residual charge in the field-effect transistor M , and its value is 50~500 k ohms. The field-effect transistor M is an N-channel MOSFET, which drives and controls the coil of the single-pole double-throw relay, and its model is such as NCE3400X. The freewheeling diode D is used to provide a current discharge path to prevent breakdown of the field-effect transistor, and its model is such as 1N5822 Schottky diode. The DC power supply VCC is used to provide the working power supply for the control circuit, and its value is 5V.

[0043] The cable coaxial structure rapid recovery device at the above-mentioned high-voltage cable cross bonding system further includes a cross bonding box 1; the cross bonding parts of the three-phase cable shielding layers of the high-voltage cable, all switching units, all lightning arresters, all grounding terminals and the control circuits of all single-pole double-throw relays are installed in the cross bonding box 1; the cross bonding box 1 is of a rectangular box structure for centralized installation and maintenance of each part. The utility model adopts the structure of "coaxial line - switching unit - lightning arrester - grounding terminal", which can not only ensure the rapid discharge of residual energy after the lightning arrester acts, maintain the potential balance of the metal sheath, prevent insulation damage, but also ensure the electromagnetic compatibility of the coaxial structure and avoid signal interference.

[0044] The working principle of the cable coaxial structure rapid recovery device at the above-mentioned high-voltage cable cross bonding system is as follows: taking the A-phase cable as an example,

[0045] When the controller receives the control instruction signal for restoring the coaxial structure, the controller outputs a high-level control signal to the control circuit of the single-pole double-throw switch in the first switching unit S 1 to control the field effect transistor M to conduct, and further control the energization of the corresponding single-pole double-throw relay coil L so that the moving contact P 2 is connected to the first static contact P 1, and the first terminal T 1 is connected to the second terminal T 2 to restore the A-phase coaxial structure of the high-voltage cable;

[0046] When the controller receives the control instruction signal for restoring the cross bonding, the controller outputs a low-level control signal to the control circuit of the single-pole double-throw switch in the first switching unit S 1 to control the field effect transistor M to disconnect, and further control the power-off of the corresponding single-pole double-throw relay coil L so that the moving contact P 2 is connected to the second static contact P 3, and the second terminal T 2, the third terminal T 3 and the fourth terminal T 4 are connected, and the high-voltage cable is in the normal cross bonding working mode.

[0047] Therefore, the utility model proposes a cable coaxial structure rapid recovery device at a high-voltage cable cross bonding system, which can realize the rapid recovery of the coaxial structure at the high-voltage cable cross bonding, and further achieve the purposes of cable impedance matching and improving the accuracy of broadband impedance testing.

[0048] Those of ordinary skill in the art will realize that the embodiments herein are provided to assist the reader in understanding the principles of the present utility model, and it should be understood that the protection scope of the present utility model is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations that do not depart from the essence of the present utility model based on these technical revelations disclosed by the present utility model, and these deformations and combinations are still within the protection scope of the present utility model.

Claims

1. A device for quickly restoring the coaxial structure of a cable at a high-voltage cable cross-bonding system, characterized in that, It includes a switching unit respectively connected to the three-phase cable shields of the high-voltage cable, and a lightning arrester and a grounding terminal connected to each switching unit; each switching unit has the same structure; The switching unit includes a first terminal, a second terminal, a third terminal, a fourth terminal and a single-pole double-throw switch; the single-pole double-throw switch includes a moving contact, a first stationary contact and a second stationary contact. The first stationary contact is connected to the first terminal, the moving contact is connected to the second terminal, and the second stationary contact and the third terminal are both connected to the fourth terminal; the fourth terminal is sequentially connected to the corresponding lightning arrester and the grounding terminal; For any one phase of the high-voltage cable, the first terminal and the second terminal of the corresponding switching unit are respectively connected to the coaxial cable led out from the cable shield before the cross-interconnection of the three-phase cable shields in this phase of the cable and the coaxial cable led out from the cable shield after the cross-interconnection of the three-phase cable shields, and the third terminal is connected to the coaxial cable led out from the cable shield before the cross-interconnection of the three-phase cable shields in another phase of the cable cross-linked with this phase of the cable.

2. The cable coaxial structure rapid recovery device at the high-voltage cable cross-bonding system according to claim 1, characterized in that, The single-pole double-throw switch is a single-pole double-throw relay.

3. The cable coaxial structure rapid recovery device at the high-voltage cable cross-bonding system according to claim 2, characterized in that, The single-pole double-throw relay is controlled by a control circuit.

4. The cable coaxial structure rapid restoration device at the high-voltage cable cross-bonding system according to claim 3, characterized in that, The control circuit includes a controller, a current-limiting resistor, a protection resistor, a field-effect transistor, a freewheeling diode and a DC power supply; the controller is connected to the gate of the field-effect transistor via the protection resistor. The DC power supply, the coil of the single-pole double-throw relay and the current-limiting resistor are connected in series and then connected to the drain of the field-effect transistor. The freewheeling diode is connected in parallel across the coil of the single-pole double-throw relay, and the source of the field-effect transistor is grounded.

5. The cable coaxial structure rapid restoration device at the high-voltage cable cross-connected system according to claim 4, characterized in that, The gate of the field-effect transistor is also grounded via a discharge resistor.

6. The cable coaxial structure rapid recovery device at the high-voltage cable cross-connected and interconnected system according to claim 4 or 5, characterized in that, The controller is an STM32F103ZET6 or DSPIC33FJ64GS606 microcontroller.

7. The cable coaxial structure rapid recovery device at the high-voltage cable cross-bonding system according to claim 1, characterized in that, It also includes a cross-interconnection box; the cross-interconnection part of the three-phase cable shields of the high-voltage cable, the switching unit, the lightning arrester, the grounding terminal and the control circuit are installed in the cross-interconnection box.

Images