A device and method for detecting a circulating voltage in a cable sheath

Abstract

The application discloses a kind of detection device and method of circulating voltage in cable sheath, device includes fixed frame, voltage dividing module, voltage detection module, power module, communication module and control module;The voltage dividing module includes voltage dividing capacitor and matching resistance, the voltage dividing capacitor is connected in series with the matching resistance, the input of the voltage dividing module is connected with cable core, the output of the voltage dividing module is connected with the voltage detection module by current type voltage transformer, the voltage detection module is connected with power module, the power module and the voltage detection module are connected with the communication module, the communication module is communicated with the control module.Using the above-mentioned detection device and method of circulating voltage in cable sheath, the setting of voltage dividing capacitor can reach 10kV voltage resistance, the detection equipment will not be punctured due to instantaneous high voltage, improve service life.

Description

Technical Field

[0001] This invention relates to the field of cable sheath testing technology, and in particular to a device and method for detecting circulating current voltage in a cable sheath. Background Technology

[0002] The basic structure of a power cable consists of four parts: the conductor, insulation layer, shielding layer, and protective layer. The conductor is the conductive part of the power cable, used to transmit electrical energy, and is the main component. The insulation layer electrically isolates the conductor from the ground and from conductors of different phases, ensuring energy transmission; it is an indispensable part of the power cable structure. A certain amount of induced current exists in the cable sheath, known as sheath circulating current. Simultaneously, multiple contact faults in the cable sheath due to rodent damage, aging, theft of grounding wires, and failure of grounding protectors will also increase the circulating current in the cable sheath. Increased current causes the armored metal sheath to heat up and deform, creating gaps, which may lead to partial discharge and affect the cable's main insulation. Therefore, to improve the maintenance level of operating cables, ensure the safety indicators of operating cables, and reduce the accident rate of cable lines, it is necessary to monitor the magnitude of the circulating current in the cable's metal sheath.

[0003] Currently, domestic online monitoring devices for circulating current in cable metal sheaths all use current transformers for detection. However, in the event of a short circuit, lightning strike, or other conditions, the circulating current voltage may rise instantaneously. The maximum withstand voltage of ordinary voltage transmitters / voltage transformers is about 1kV. Instantaneous high voltage may break down the voltage transmitter or even affect secondary equipment. Summary of the Invention

[0004] The purpose of this invention is to provide a device and method for detecting circulating voltage in cable sheaths. The voltage divider capacitor can withstand a voltage of 10kV, and the detection equipment will not be broken down due to instantaneous high voltage, thus improving its service life.

[0005] To achieve the above objectives, the present invention provides a device for detecting circulating current voltage in a cable sheath, comprising a mounting frame, a voltage divider module, a voltage detection module, a power supply module, a communication module, and a control module;

[0006] The voltage divider module includes a voltage divider capacitor and a matching resistor. The voltage divider capacitor and the matching resistor are connected in series. The input terminal of the voltage divider module is connected to the cable core. The output terminal of the voltage divider module is connected to the voltage detection module through a current-type voltage transformer. The voltage detection module is connected to the power supply module. Both the power supply module and the voltage detection module are connected to the communication module. The communication module communicates with the control module.

[0007] Preferably, the power module includes an inductive current transformer, a rectifier and voltage regulator module, a rechargeable battery, and a voltage regulator output module. The voltage regulator output module is connected to the rechargeable battery, the rechargeable battery is connected to the rectifier and voltage regulator module, the rectifier and voltage regulator module is connected to the inductive current transformer, and the inductive current transformer is sleeved on a cable.

[0008] Preferably, the voltage detection module includes a sampling resistor, an AD conversion circuit, and a voltage comparison circuit. One input terminal of the voltage comparison circuit is connected to the sampling resistor, and the sampling resistor is connected to the AD conversion circuit. The other input terminal of the voltage comparison circuit is connected to the voltage regulation output module.

[0009] Preferably, the communication module is connected to the output terminal of the voltage comparator through a driving circuit, the communication module is equipped with an alarm circuit, the alarm circuit is equipped with an indicator light and a buzzer, the communication module is connected to the voltage regulator output module, and the communication module is connected to the AD conversion circuit.

[0010] Preferably, the fixing frame includes a first fixing rod, a second fixing rod, and a fixing plate. The first fixing rod and the second fixing rod are fixed to both ends of the fixing plate, respectively. A fixing ring is provided at the top end of both the first fixing rod and the second fixing rod. A fixing screw is provided on the fixing ring. A wire clamping component is fixed to the side of the first fixing rod. Two wire clamping components are symmetrically arranged on the side of the second fixing rod. A clamping groove is opened on the inner side of the wire clamping component. At least two rows of mounting holes for installing the wire clamping components are opened on the side of the first fixing rod and the second fixing rod.

[0011] Preferably, the fixing ring of the second fixing rod has a connecting through hole, the connecting through hole is threaded to one end of the connecting rod, and the other end of the connecting rod is threaded to the inductive current transformer.

[0012] Preferably, the voltage divider module, the voltage detection module, the power supply module, and the communication module are all fixed on a fixed plate and covered with a protective cover, and the indicator light and the buzzer are set on the protective cover.

[0013] A detection method based on a detection device for circulating current voltage in a cable sheath, comprising the following specific steps:

[0014] Step S1: Securely connect the device to the cable under test using a mounting bracket;

[0015] Step S2: Start the voltage detection module and power supply module;

[0016] Step S3: When the detected voltage of the sampling resistor is lower than the comparison voltage of the voltage comparison circuit, the voltage value of the sampling resistor is stored in the communication module through the AD conversion circuit. When the detected voltage of the sampling resistor is higher than the comparison voltage of the voltage comparison circuit, the communication module is activated. The communication module sends an alarm signal and stored data to the control module to notify the staff. At the same time, the alarm circuit performs an audible and visual alarm.

[0017] Preferably, the relationship between the sampling resistor and the measured voltage is as follows:

[0018]

[0019] Among them, U L The voltage being measured is Ux, the voltage across the sampling resistor is R. x X is the resistance value of the sampling resistor. c R is the capacitive reactance of the voltage divider capacitor, and R is the resistance of the matching resistor.

[0020] Therefore, the present invention employs the above-mentioned detection device and method for circulating current voltage in cable sheath. The voltage divider capacitor can achieve a withstand voltage of 10kV, and the detection equipment will not be broken down due to instantaneous high voltage, thus improving its service life.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the principle of a device for detecting circulating current voltage in a cable sheath according to the present invention.

[0023] Figure 2 This is a schematic diagram of the fixing frame structure of the present invention.

[0024] Figure Labels

[0025] 1. Cable under test; 2. First fixing rod; 3. Second fixing rod; 4. Cable clamp; 5. Fixing ring; 6. Fixing plate; 7. Buzzer; 8. Indicator light; 9. Connecting rod; 10. Inductive current transformer; 11. Protective cover. Detailed Implementation

[0026] Example

[0027] Figure 1 This is a schematic diagram illustrating the principle of a device for detecting circulating current voltage in a cable sheath according to the present invention. Figure 2 The figure shows a schematic diagram of the fixing frame structure of the present invention. A device for detecting circulating current voltage in a cable sheath includes a fixing frame, a voltage divider module, a voltage detection module, a power supply module, a communication module, and a control module.

[0028] The mounting bracket includes a first fixing rod 2, a second fixing rod 3, and a fixing plate 6. The first fixing rod 2 and the second fixing rod 3 are fixed to both ends of the fixing plate 6, respectively. A fixing ring 5 is provided at the top of both the first fixing rod 2 and the second fixing rod 3, and a fixing screw is provided on the fixing ring 5 to facilitate the fixing of the mounting bracket to the cable 1 under test. A wire clamping component 4 is fixed to the side of the first fixing rod 2, and two wire clamping components 4 are symmetrically arranged on the side of the second fixing rod 3. A slot is provided on the inner side of each wire clamping component 4 for fixing the wiring. At least two rows of mounting holes for installing the wire clamping components are provided on the sides of the first fixing rod 2 and the second fixing rod 3. In this embodiment, two rows are provided, and the wire clamping components 4 are fixed to the corresponding mounting holes by screws. A connecting through hole is provided on the fixing ring 5 of the second fixing rod 3, and the connecting through hole is threaded to one end of a connecting rod 9. The other end of the connecting rod 9 is threaded to the inductive current transformer 10. The current-type voltage transformer, voltage divider module, voltage detection module, power supply module and communication module are all fixed on the fixing plate 6 and covered with a protective cover 11. The indicator 8 and the buzzer 7 are set on the protective cover 11.

[0029] The voltage divider module includes a voltage-dividing capacitor (C) and a matching resistor (R). The voltage-dividing capacitor and the matching resistor are connected in series. The voltage-dividing capacitor is designed to withstand a voltage of 10kV, preventing the testing equipment from being damaged by a sudden high voltage. The input terminal of the voltage divider module is connected to the cable core of the cable under test (1). Under normal operating conditions, the voltage is low, and the voltage divider module does not affect the operation of the cable. The output terminal of the voltage divider module is connected to the voltage detection module through a current-type voltage transformer. The voltage detection module is connected to the power supply module, which includes an inductive current transformer, a rectifier and voltage regulator module, a rechargeable battery, and a regulated output module. The regulated output module is connected to the rechargeable battery, which is connected to the rectifier and voltage regulator module. The rectifier and voltage regulator module is connected to the inductive current transformer, which is mounted on the cable to provide power to the device. The voltage detection module includes a sampling resistor, an AD conversion circuit, and a voltage comparator circuit. One input terminal of the voltage comparator circuit is connected to the sampling resistor, which is connected to the AD conversion circuit. The other input terminal of the voltage comparator circuit is connected to the regulated output module. The communication module is connected to the output of the voltage comparator via a driver circuit. The communication module includes an alarm circuit with an indicator light and a buzzer. It is also connected to the voltage regulator output module and the AD conversion circuit. The power supply module and voltage detection module are both connected to the communication module, which in turn communicates with the control module.

[0030] A detection method based on a detection device for circulating current voltage in a cable sheath, comprising the following specific steps:

[0031] Step S1: Securely connect the device to the cable under test using a mounting bracket.

[0032] Step S2: Start the voltage detection module and power supply module to detect the measured voltage value in real time.

[0033] The formula relating the sampling resistor to the measured voltage is as follows:

[0034]

[0035] Among them, U L The voltage being measured is Ux, the voltage across the sampling resistor is R. x X is the resistance value of the sampling resistor. c R is the capacitive reactance of the voltage divider capacitor, and R is the resistance of the matching resistor.

[0036] Step S3: When the detected voltage of the sampling resistor is lower than the comparison voltage of the voltage comparison circuit, the voltage value of the sampling resistor is stored in the communication module through the AD conversion circuit. When the detected voltage of the sampling resistor is higher than the comparison voltage of the voltage comparison circuit, the communication module is activated. The communication module sends an alarm signal and stored data to the control module to notify the staff. At the same time, the alarm circuit performs an audible and visual alarm.

[0037] Therefore, the present invention employs the above-mentioned detection device and method for circulating current voltage in cable sheath. The voltage divider capacitor can achieve a withstand voltage of 10kV, and the detection equipment will not be broken down due to instantaneous high voltage, thus improving its service life.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A device for detecting circulating current voltage in a cable sheath, characterized in that: It includes a mounting bracket, a voltage divider module, a voltage detection module, a power supply module, a communication module, and a control module; The voltage divider module includes a voltage divider capacitor and a matching resistor. The voltage divider capacitor and the matching resistor are connected in series. The input terminal of the voltage divider module is connected to the cable core. The output terminal of the voltage divider module is connected to the voltage detection module through a current-type voltage transformer. The voltage detection module is connected to the power supply module. Both the power supply module and the voltage detection module are connected to the communication module. The communication module communicates with the control module. The power module includes an inductive current transformer, a rectifier and voltage regulator module, a rechargeable battery, and a voltage regulator output module. The voltage regulator output module is connected to the rechargeable battery, the rechargeable battery is connected to the rectifier and voltage regulator module, the rectifier and voltage regulator module is connected to the inductive current transformer, and the inductive current transformer is sleeved on a cable. The fixing frame includes a first fixing rod, a second fixing rod, and a fixing plate. The first fixing rod and the second fixing rod are fixed to both ends of the fixing plate, respectively. A fixing ring is provided at the top of each of the first and second fixing rods. A fixing screw is provided on the fixing ring. A wire clamping component is fixed to the side of the first fixing rod. Two wire clamping components are symmetrically arranged on the side of the second fixing rod. A clamping groove is opened on the inner side of the wire clamping component. At least two rows of mounting holes for installing the wire clamping components are opened on the sides of the first and second fixing rods. A connecting through hole is opened on the fixing ring of the second fixing rod. The connecting through hole is threaded to one end of the connecting rod, and the other end of the connecting rod is threaded to the inductive current transformer.

2. The device for detecting circulating current voltage in a cable sheath according to claim 1, characterized in that: The voltage detection module includes a sampling resistor, an AD conversion circuit, and a voltage comparison circuit. One input terminal of the voltage comparison circuit is connected to the sampling resistor, and the sampling resistor is connected to the AD conversion circuit. The other input terminal of the voltage comparison circuit is connected to the voltage regulation output module.

3. The device for detecting circulating current voltage in a cable sheath according to claim 2, characterized in that: The communication module is connected to the output terminal of the voltage comparison circuit through a driving circuit. The communication module is equipped with an alarm circuit, which includes an indicator light and a buzzer. The communication module is connected to the voltage regulator output module and the AD conversion circuit.

4. The device for detecting circulating current voltage in a cable sheath according to claim 3, characterized in that: The voltage divider module, the voltage detection module, the power supply module, and the communication module are all fixed on the mounting plate and covered with a protective cover. The indicator light and the buzzer are mounted on the protective cover.

5. A detection method for a detection device for circulating current voltage in a cable sheath based on any one of claims 1-4, characterized in that, The specific steps are as follows: Step S1: Securely connect the device to the cable under test using a mounting bracket; Step S2: Start the voltage detection module and power supply module; Step S3: When the detected voltage of the sampling resistor is lower than the comparison voltage of the voltage comparison circuit, the voltage value of the sampling resistor is stored in the communication module through the AD conversion circuit. When the detected voltage of the sampling resistor is higher than the comparison voltage of the voltage comparison circuit, the communication module is activated. The communication module sends an alarm signal and stored data to the control module to notify the staff. At the same time, the alarm circuit performs an audible and visual alarm.

6. The device for detecting circulating current voltage in a cable sheath according to claim 5, characterized in that: The formula relating the sampling resistor to the measured voltage is as follows: ， in, The voltage being measured. Sampling resistor voltage, The value of the sampling resistor. This is the capacitive reactance of the voltage divider capacitor. The resistance value is for the matching resistor.

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