CN105842520A - Cable grounding circulation monitoring device - Google Patents

Abstract

The invention provides a cable grounding circulation monitoring device. The device comprises a data acquisition module which is connected with a transmission cable and is used for acquiring the cable grounding circulation state information of the transmission cable and converting the information into an electrical signal, a communication module which is used for transmitting the electrical signal of the grounding circulation state information, and a control device which is used for receiving the electrical signal of the grounding circulation state information and analyzing the electrical signal to acquire the cable grounding circulation state data of the transmission cable. The cable grounding circulation state is monitored online in real time.

Description

Cable grounding loop current monitoring device

technical field

The invention relates to the field of electrical monitoring, in particular to a cable grounding circulation monitoring device.

Background technique

In my country, high-voltage transmission cables of 110KV and above are mainly single-core cables. When the metal sheath of the single-core cable and the cable core pass through the alternating current, the magnetic field lines will be hinged, so that a higher induced voltage will appear at both ends.

There is one or more layers of metal shielding structure outside the main insulation of the transmission cable, which is used to shield the electric field of the inner conductor of the cable. This construction of the cable is equivalent to a single-turn transformer: an alternating current on the inner cable core will induce an alternating electromotive force on the outer cable metal sheath or copper shield. If both ends of the cable shielding layer or the metal sheath are grounded, a circulating current will be formed under the action of the induced electromotive force, and the circulating current value is proportional to the load current of the wire core, the resistance of the shielding layer and the earth loop, and other factors. When a large grounding loop current flows through the grounding point (equivalent resistance), the grounding part will heat up and catch fire, thereby destroying the main insulation, causing cable insulation breakdown, and causing line tripping. If one or both ends of the cable copper shield or metal sheath are suspended, the circulating current value will be very small, but the outer sheath of the cable shield and the metal sheath suspended end will bear the induced voltage to the ground, and the voltage value is related to the core load. The current is directly proportional to factors such as cable shielding and metal sheath length. When the cable is long and the load is heavy, high voltage will be induced on the metal sheath. If the current cannot be discharged through the overvoltage limiter of the metal sheath, the outer sheath of the cable may be broken down, causing multiple points of the metal sheath to be grounded, forming a circulating current, and then developing into a fault or even spreading to a cable channel fire.

In order to prevent circulating current or overvoltage on the cable shield and metal sheath, the regulations require that the cable shield and metal sheath must be grounded directly at one end and grounded through a voltage limiter at the other end.

The outer sheath of the cable in operation may be damaged at multiple points due to possible mechanical damage, chemical corrosion, and rodent damage, water ingress in the protection box, breakdown of the overvoltage protector, and disconnection of the grounding wire of the metal sheath etc. lead to changes in the grounding mode of the metal sheath. After the grounding mode of the cable metal sheath is abnormal, the value of the sheath circulation will change accordingly. If it cannot be found and dealt with in time, it will cause the cable to catch fire, insulation breakdown, and power grid blackout accident. Therefore, it is very necessary to know whether the status of the grounding mode is normal by collecting the grounding current of the metal sheath of the cable.

It is time-consuming and labor-intensive to collect the data of cable grounding circulation on site through conventional manual inspection, and the inspection cycle is long, so it cannot be monitored in real time.

The existing cable grounding circulation monitoring terminal can only measure the absolute value of the grounding current of the metal sheath of each phase of the cable, but cannot judge the three-phase grounding current unbalance, grounding current and load current ratio and other data indicators. Horizontal and vertical multi-parameter comparative analysis function.

From the perspective of anti-theft, the existing grounding current monitoring terminal can indirectly judge whether the grounding copper bar or grounding wire has been stolen by measuring the grounding current, but cannot perform the anti-theft monitoring function when the cable is powered off or overhauled.

Therefore, how to realize real-time on-line monitoring of cable ground circulation status has become an urgent problem to be solved.

Contents of the invention

The technical problem to be solved by the invention is to realize real-time on-line monitoring of the cable grounding circulation state.

Therefore, according to the first aspect, the embodiment of the present invention discloses a cable grounding circulation monitoring device, including:

The data acquisition module is used to connect to the power transmission cable, and is used to collect the cable ground circulation status information of the power transmission cable and convert it into an electrical signal; the communication module is used to send the electrical signal of the ground circulation status information; the controller is used to receive the ground circulation status information. The electrical signal of the circulation state information is analyzed to obtain the cable grounding circulation state data of the transmission cable.

Preferably, the data acquisition module includes: a plurality of sensors, which are respectively connected to the power transmission cable, and respectively collect different state information of the cable grounding circulation of the power transmission cable; a data collector, which is used to respectively receive different states collected by a plurality of sensors information, and convert them into electrical signals corresponding to each state information.

Preferably, the multiple sensors include: a current transformer, configured to be arranged on the ground wire of the metal sheath of the power transmission cable, and used to collect the ground current signal of the metal sheath; a shock sensor, used to be arranged on the joint of the power transmission cable , used to collect the location information of the connector.

Preferably, the cable ground circulation monitoring device also includes: an audible and visual alarm, connected to the data collector, for outputting an alarm signal under the alarm excitation signal output by the data collector; multiple sensors also include: an inclination sensor, arranged on The ground wire or protection wire of the transmission cable is used to send a trigger signal for representing an output alarm excitation signal to the data collector after the ground wire is cut off and triggered.

Preferably, the audible and visual alarm is set at the cable grounding end of the power transmission cable.

Preferably, the sound and light alarm is also used to output an alarm signal in response to an alarm trigger signal output by the data collector under the control of the controller.

Preferably, the communication module is a wireless communication module.

Preferably, the cable ground loop current monitoring device further includes: a display module, connected to the data collector, for displaying different status information in a visual manner.

The technical solution of the present invention has the following advantages:

The cable grounding circulation monitoring device provided by the embodiment of the present invention can collect the cable grounding circulation state information of the power transmission cable through the data acquisition module and convert it into an electrical signal, and can send the electrical signal of the grounding circulation state information through the communication module, and use the controller to receive The electrical signal is analyzed to obtain the cable grounding circulation state data of the transmission cable. Thus, the real-time on-line monitoring of the cable grounding circulation status is realized.

As a preferred technical solution, the data acquisition module includes multiple sensors, so that multiple data indicators can be monitored in real time.

As a preferred technical solution, the acousto-optic alarm outputs an alarm signal under the alarm excitation signal output by the data collector, so that when the three-phase imbalance or the ground current is abnormal, the abnormal information can be effectively fed back.

Description of drawings

In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the specific implementation or description of the prior art. Obviously, the accompanying drawings in the following description The drawings show some implementations of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

Fig. 1 is a schematic structural diagram of a cable grounding circulation monitoring device in an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a data collector in an embodiment of the present invention.

detailed description

The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as there is no conflict with each other.

In order to realize real-time online monitoring of the cable ground circulation status, this embodiment discloses a cable ground circulation monitoring device. Please refer to FIG. and controller 3, where:

The data acquisition module 1 is used to connect to the power transmission cable, and is used to collect the cable ground circulation status information of the power transmission cable and convert it into an electrical signal. In a specific embodiment, the cable ground circulation status type can be determined according to the monitoring requirements of the transmission cable, such as data indicators such as three-phase ground current unbalance degree, ground current and load current ratio. In a preferred embodiment, the data acquisition module 1 includes: a plurality of sensors, which are used to connect to the power transmission cable respectively, and respectively collect different state information of the cable grounding loop current of the power transmission cable; the data collector 11 is used to receive a plurality of sensors respectively The collected different state information is converted into electrical signals corresponding to each state information. In a preferred embodiment, the plurality of sensors may include: a current transformer 12 and a vibration sensor 13, wherein the current transformer 12 is used to be arranged on the ground wire of the metal sheath of the power transmission cable, and is used to collect the metal sheath The ground current signal; the shock sensor 13 is used to be arranged on the joint of the power transmission cable, and is used to collect the position information of the joint, and the position information can indicate whether the cable joint is dislocated due to trauma.

The communication module 2 is used for sending an electrical signal of ground circulation state information. In a preferred embodiment, the communication module 2 can be a wireless communication module based on the Internet, preferably a GSM/GPRS communication module. When the wireless communication module is a GSM/GPRS communication module, not only the data exchange of the ground circulation state information can be realized, but also the information can be sent through the GSM short message.

The controller 3 is used for receiving the electrical signal of the ground circulation status information and analyzing and obtaining the cable ground circulation status data of the power transmission cable. Through the circulating current status data received by the controller 3, the ability to calculate multiple data indicators such as three-phase ground current unbalance degree, ground current and load current ratio, etc. In a specific embodiment, the controller 3 can be set in the monitoring center, specifically, the controller 3 can be set separately, or the monitoring host of the monitoring center can be used as the controller 3 .

In order to monitor whether the cable is maliciously stolen, in a preferred embodiment, the cable ground loop monitoring device can further include: an audible and visual alarm 4 and an inclination sensor 14, wherein the audible and visual alarm 4 is connected with the data collector 11, It is used to output an alarm signal under the alarm excitation signal output by the data collector 11, and the alarm signal may be sound, light or a combination of the two. The inclination sensor 14 is arranged on the ground wire or the protection wire of the power transmission cable, and is used to send a trigger signal for representing an output alarm excitation signal to the data collector 11 after the ground wire is cut off and triggered, so that the sound and light alarm 4 outputs an alarm Signal. In a preferred embodiment, the sound and light alarm 4 can be set at the grounding end of the power transmission cable, so as to better send out an alarm signal to the outside world.

In a preferred embodiment, the sound and light alarm 4 is also used to output an alarm signal in response to an alarm trigger signal output by the data collector 11 under the control of the controller 3 . Specifically, the controller 3 can control the data collector 11 to output an alarm trigger signal, and the sound and light alarm 4 outputs an alarm signal in response to the alarm trigger signal. Thus, when suspicious data is monitored by the monitoring center, the sound and light alarm 4 can be remotely triggered to give an alarm.

In a preferred embodiment, the cable ground loop current monitoring device further includes a display module 5 connected to the data collector 11 for visually displaying different status information.

Please refer to Fig. 2, which is a schematic diagram of a structure of the data collector 11. In a specific embodiment, the data collector 11 includes: a microprocessor 111, which can be, for example, a single-chip microcomputer, DSP, etc. with logic The chip of operation function, microprocessor 111 is used for realizing the control of data interaction and data operation; The data collector 11 may further include: current conversion interface 112, AI interface 113, DI interface 114, DO interface 115, serial port module 116 and any one or more of SPI interface 117, wherein, the current sensor is connected with the microprocessor 111 through the current conversion interface, the inclination sensor 14 can be connected with the microprocessor 111 through the AI interface 113, and the shock sensor 13 can be connected with the microprocessor 111 through the DI Interface 114 is connected with microprocessor 111, sound and light alarm 4 can be connected with microprocessor 111 by DO interface 115, liquid crystal display 5 can be connected with this microprocessor 111 by SPI interface 117, communication module 2 is by serial port module 116 connected to the microprocessor.

The cable ground circulation monitoring device disclosed in this embodiment can collect the cable ground circulation status information of the power transmission cable through the data acquisition module and convert it into an electrical signal, and can send the electrical signal of the ground circulation status information through the communication module, and use the controller to receive and analyze it. The electrical signal yields cable ground loop status data for the transmission cable. Thus, the real-time on-line monitoring of the cable grounding circulation status is realized. Then, it solves the problem that the collection of cable ground circulation is manual, and the data is neither timely nor accurate, and realizes real-time monitoring of cable ground circulation data, real-time judgment of three-phase ground current imbalance, ground current and load current ratio, etc. Multiple data indicators. With the local display function, it is convenient for inspectors to check in real time; with sound and light alarm, when the three-phase unbalance or the ground current is abnormal, the local and remote alarms will be sent. When the ground wire or protection wire is maliciously cut, the information can be sent immediately.

In a preferred embodiment, the data acquisition module includes a plurality of sensors, so that multiple data indicators can be monitored in real time.

In a preferred embodiment, the acousto-optic alarm outputs an alarm signal under the alarm excitation signal output by the data collector, so that when the three-phase imbalance or the ground current is abnormal, the abnormal information can be effectively fed back.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in different forms can also be made. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (8)

1. A cable grounding circulation monitoring device, characterized in that, comprising: The data acquisition module is used to connect to the power transmission cable, and is used to collect the cable ground circulation status information of the power transmission cable and convert it into an electrical signal; A communication module, configured to send an electrical signal of the ground circulation state information; The controller is configured to receive the electrical signal of the ground circulation state information and analyze and obtain the cable ground circulation state data of the power transmission cable. 2. The cable grounding circulation monitoring device as claimed in claim 1, wherein said data acquisition module comprises: A plurality of sensors are used to be respectively connected to the power transmission cable, and respectively collect different status information of the cable ground circulation of the power transmission cable; The data collector is configured to respectively receive different state information collected by the plurality of sensors, and convert them into electrical signals corresponding to each state information. 3. The cable grounding loop current monitoring device as claimed in claim 2, wherein said plurality of sensors comprise: A current transformer, configured to be arranged on the ground wire of the metal sheath of the power transmission cable, and used to collect the ground current signal of the metal sheath; The shock sensor is configured to be arranged on the joint of the power transmission cable, and is used to collect position information of the joint. 4. The cable grounding circulation monitoring device according to claim 2 or 3, further comprising: An audible and visual alarm, connected to the data collector, for outputting an alarm signal under the alarm excitation signal output by the data collector; The plurality of sensors also includes: The inclination sensor is arranged on the ground wire or protection wire of the power transmission cable, and is used to send a trigger signal for representing and outputting the alarm excitation signal to the data collector after the ground wire is cut off and triggered. 5. The cable grounding circulation monitoring device according to claim 4, characterized in that, the audible and visual alarm is arranged at the cable grounding end of the power transmission cable. 6 . The cable grounding circulation monitoring device according to claim 4 , wherein the sound and light alarm is further configured to output an alarm signal in response to an alarm trigger signal output by the data collector under the control of the controller. 7. The cable ground circulation monitoring device according to any one of claims 1-3, wherein the communication module is a wireless communication module. 8. The cable grounding circulation monitoring device according to claim 2 or 3, further comprising: The display module is connected with the data collector and is used to display the different state information in a visual manner.