High-voltage cable metal sheath circulating current suppression device capable of being automatically put in or withdrawn

Abstract

The utility model relates to a high-voltage cable metal sheath circulating current suppression device capable of being automatically put in or withdrawn, which belongs to the field of cable protection, and aims to solve the problems that the service life of a cable is shortened due to grounding circulating current generated by a metal sheath, and the tail end of each phase of cable sheath is respectively connected with a three-way switch signal input end of a three-position dial switch; the first switching signal output end of each three-position dial switch is connected with one end of a first resistance regulator, the second switching signal output end of each three-position dial switch is connected with one end of a second resistance regulator, and the third switching signal output end of each three-position dial switch is connected with one end of a third resistance regulator. The other end of the first resistance regulator, the other end of the second resistance regulator and the other end of the third resistance regulator are connected with a protection grounding box. The current transformer collects a current signal of the high-voltage cable sheath and sends the current signal to the controller, and the signal output by the controller controls the resistance value of the first resistance regulator and / or the second resistance regulator. The method is used for restraining circulation.

Description

Technical Field

[0001] This utility model belongs to the field of cable protection and relates to a circulating current suppression device. Background Technology

[0002] Power cables consist of a conductor, insulation layer, and protective layer. The main function of the protective layer is to protect the main insulation layer from mechanical damage and various environmental factors such as water, sunlight, biological agents, and fire during laying and operation. Therefore, the condition of the protective layer directly affects the safe operation and service life of the cable. There are three main types of protective layers: metal sheaths, rubber-plastic sheaths, and composite sheaths. Metal sheaths are widely used because they are completely waterproof, preventing water and other harmful substances from entering the cable insulation.

[0003] However, due to the cable load current and other currents, a large induced voltage will be induced in the metal sheath. When the line length is long, the induced voltage is very large, which poses a safety hazard. Therefore, the metal sheath must be grounded. At the same time, a grounding current will be formed on the metal sheath, also known as sheath grounding loop current. If the sheath grounding loop current is too large, it will threaten the safety of the operators and cause excessive cable loss, which may damage the sheath insulation and shorten the cable's service life. Utility Model Content

[0004] The purpose of this invention is to solve the problem of grounding current generated by metal sheaths, which damages sheath insulation and shortens cable service life. A high-voltage cable metal sheath circulating current suppression device with automatic activation or deactivation is proposed.

[0005] A high-voltage cable metal sheath circulating current suppression device that automatically engages or disengages, the device comprising a 3-position DIP switch, a current transformer, a controller, a first resistor regulator, a second resistor regulator, and a third resistor regulator.

[0006] Each phase cable sheath is connected to a three-way switch signal input terminal of a 3-position DIP switch. The first switch signal output terminal of each 3-position DIP switch is connected to one end of resistor regulator No. 1, the second switch signal output terminal of each 3-position DIP switch is connected to one end of resistor regulator No. 2, and the third switch signal output terminal of each 3-position DIP switch is connected to one end of resistor regulator No. 3. The other ends of resistor regulator No. 1, resistor regulator No. 2, and resistor regulator No. 3 are all connected to the protective grounding box.

[0007] The current transformer is installed on the grounding wire connecting the high-voltage cable sheath and the protective grounding box; the current transformer is used to collect the current signal of the high-voltage cable sheath.

[0008] The current signal output terminal of the current transformer is connected to the current signal input terminal of the controller, and the signal output by the controller controls the resistance value of resistor regulator No. 1 and / or resistor regulator No. 2.

[0009] Preferably, the first resistor regulator includes sliding rheostats R1-R2;

[0010] The first switch signal output terminal of each 3-position DIP switch is connected to one end of the sliding rheostat R1, the other end of the sliding rheostat R1 is connected to one end of the sliding rheostat R2, and the other end of the sliding rheostat R2 is connected to the protective grounding box.

[0011] The signal output by the controller controls the resistance values ​​of the sliding rheostats R1 and R2.

[0012] Preferably, the second resistor regulator includes a sliding rheostat R3 and a resistor R4;

[0013] The second switch signal output terminal of each 3-position DIP switch is connected to one end of the sliding rheostat R3, the other end of the sliding rheostat R3 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the protective grounding box.

[0014] The signal output by the controller controls the resistance value of the sliding rheostat R3.

[0015] Preferably, the third resistor regulator includes resistor R5;

[0016] The third switch signal output terminal of each 3-position DIP switch is connected to one end of resistor R5, and the other end of resistor R5 is connected to the protective grounding box.

[0017] The signal output by the controller controls the resistance value of the sliding rheostat R3.

[0018] Preferably, the controller is implemented using a single-chip microcontroller of model STC89C52. The beneficial effects of this invention are:

[0019] This invention uses a current transformer to collect the circulating current signal at the end of the three-phase high-voltage cable sheath and transmits it to a controller. The controller calculates the equivalent resistance of the single-phase cable sheath based on the magnitude of the single-phase circulating current. By controlling the resistance values ​​of resistor regulators 1 and 2, and simultaneously by toggling a DIP switch, the corresponding resistance values ​​of resistor regulators 1, 2, or 3 are activated. The corresponding resistance values ​​are used to suppress the circulating current, thereby protecting the cable.

[0020] This utility model provides a three-phase high-voltage cable sheath that uses a single set of resistance regulators (resistance regulator No. 1, resistance regulator No. 2, and resistance regulator No. 3), which saves on component costs and effectively suppresses circulating current. Attached Figure Description

[0021] Figure 1 A schematic diagram of the principle of a high-voltage cable metal sheath circulating current suppression device that can be automatically engaged or disengaged.

[0022] Figure 2 for Figure 1 A magnified view of a portion of the image. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0026] Example:

[0027] A high-voltage cable metal sheath circulating current suppression device that automatically engages or disengages, the device comprising a 3-position DIP switch 1, a current transformer 2, a controller, a first resistor regulator, a second resistor regulator, and a third resistor regulator.

[0028] Each phase cable sheath end is connected to a three-way switch signal input terminal of a 3-position DIP switch 1. The first switch signal output terminal of each 3-position DIP switch 1 is connected to one end of resistor regulator 1. The second switch signal output terminal of each 3-position DIP switch 1 is connected to one end of resistor regulator 2. The third switch signal output terminal of each 3-position DIP switch 1 is connected to one end of resistor regulator 3. The other ends of resistor regulator 1, resistor regulator 2, and resistor regulator 3 are all connected to the protective grounding box.

[0029] Current transformer 2 is installed on the grounding wire connecting the high-voltage cable sheath and the protective grounding box; current transformer 2 is used to collect the current signal of the high-voltage cable sheath.

[0030] The current signal output terminal of the current transformer is connected to the current signal input terminal of the controller, and the signal output by the controller controls the resistance value of resistor regulator No. 1 and / or resistor regulator No. 2.

[0031] Specifically, a DIP switch is used to select any one of the three resistor regulators (No. 1, No. 2, and No. 3) to suppress the corresponding circulating current, allowing for fast switching. Furthermore, since the resistance values ​​of the three resistor regulators are different, the resistance values ​​of No. 1 and No. 2 can be adjusted using a sliding rheostat, providing flexible control and better matching of the resistance value with the circulating current, resulting in a significant suppression effect.

[0032] Further defining the composition of resistor regulator No. 1: resistor regulator No. 1 includes sliding rheostats R1-R2;

[0033] The first switch signal output terminal of each 3-position DIP switch 1 is connected to one end of the sliding rheostat R1, the other end of the sliding rheostat R1 is connected to one end of the sliding rheostat R2, and the other end of the sliding rheostat R2 is connected to the protective grounding box.

[0034] The signal output by the controller controls the resistance values ​​of the sliding rheostats R1 and R2.

[0035] Specifically, depending on the magnitude of the circulating current, only the sliding rheostat R1 or only the sliding rheostat R2 can be adjusted so that the adjusted resistance value can match the circulating current and thus suppress the circulating current.

[0036] Further defining the composition of resistor regulator No. 2: resistor regulator No. 2 includes sliding rheostat R3 and resistor R4;

[0037] The second switch signal output terminal of each 3-position DIP switch 1 is connected to one end of the sliding rheostat R3, the other end of the sliding rheostat R3 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the protective grounding box.

[0038] The signal output by the controller controls the resistance value of the sliding rheostat R3.

[0039] Specifically, resistor R4 is a fixed resistor, and circulating current can be suppressed by controlling the resistance value of the sliding rheostat R3.

[0040] The resistance values ​​of resistors 1, 2, and 3, from largest to smallest, are listed as resistor 1, resistor 2, and resistor 3, respectively. The three lines can be connected according to the circulating current.

[0041] Further defining the composition of resistor regulator No. 3: resistor regulator No. 3 includes resistor R5;

[0042] The third switch signal output terminal of each 3-bit DIP switch 1 is connected to one end of resistor R5, and the other end of resistor R5 is connected to the protective grounding box.

[0043] The signal output by the controller controls the resistance value of the sliding rheostat R3.

[0044] The preferred controller model is: the controller is implemented using a single-chip microcomputer of model STC89C52.

[0045] While specific embodiments of the present invention have been described herein with reference to them, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A high voltage cable metallic sheath loop current suppression device with automatic throw-in or throw-out, characterized in that, The device comprises a 3-bit dial switch (1), a current transformer (2), a controller, a first resistance regulator, a second resistance regulator and a third resistance regulator. Each of the 3-bit dial switches (1) is connected to the three-way switch signal input end of the cable sheath of each phase, the first-way switch signal output end of each of the 3-bit dial switches (1) is connected to one end of the first resistance regulator, the second-way switch signal output end of each of the 3-bit dial switches (1) is connected to one end of the second resistance regulator, the third-way switch signal output end of each of the 3-bit dial switches (1) is connected to one end of the third resistance regulator, the other end of the first resistance regulator, the other end of the second resistance regulator and the other end of the third resistance regulator are connected to the protection grounding box. The current transformer (2) is sleeved on the grounding wire connected between the high-voltage cable sheath and the protection grounding box; the current transformer (2) is used for collecting the current signal of the high-voltage cable sheath. The current signal output end of the current transformer is connected to the current signal input end of the controller, and the signal output by the controller controls the resistance value of the first resistance regulator and / or the second resistance regulator.

2. The automatically engaged or disengaged high voltage cable metal sheath loop current suppression device of claim 1, wherein, The first resistance regulator comprises a slide rheostat R1-R2. The first-way switch signal output end of each of the 3-bit dial switches (1) is connected to one end of the slide rheostat R1, the other end of the slide rheostat R1 is connected to one end of the slide rheostat R2, and the other end of the slide rheostat R2 is connected to the protection grounding box. The signal output by the controller controls the resistance value of the slide rheostats R1 and R2.

3. The automatically engaged or disengaged high voltage cable metal sheath loop current suppression device of claim 1, wherein, The second resistance regulator comprises a slide rheostat R3 and a resistance R4. The second-way switch signal output end of each of the 3-bit dial switches (1) is connected to one end of the slide rheostat R3, the other end of the slide rheostat R3 is connected to one end of the resistance R4, and the other end of the resistance R4 is connected to the protection grounding box. The signal output by the controller controls the resistance value of the slide rheostat R3.

4. The automatically engaged or disengaged high voltage cable metal sheath loop current suppression device of claim 1, wherein, The third resistance regulator comprises a resistance R5. The third-way switch signal output end of each of the 3-bit dial switches (1) is connected to one end of the resistance R5, and the other end of the resistance R5 is connected to the protection grounding box. The signal output by the controller controls the resistance value of the slide rheostat R3.

5. The automatically engaged or disengaged high voltage cable metal sheath loop current suppression device of claim 1, wherein, The controller is a single-chip microcomputer with the model STC89C52.

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