CN112067946A - Cable sheath fault monitoring device and method for broadcasting synchronous signals by multiple Rogowski coils - Google Patents
Cable sheath fault monitoring device and method for broadcasting synchronous signals by multiple Rogowski coils Download PDFInfo
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- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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Abstract
The invention relates to a cable sheath fault monitoring device and method for broadcasting synchronous signals by multiple Rogowski coils, wherein the method comprises the following steps: step 1, setting primary and secondary transformation ratios of Rogowski coils in a grounding current acquisition sensor and a cable load acquisition sensor to be less than or equal to 1000: 1; step 2, mounting the grounding current acquisition sensor at the direct connection place or the cross interconnection place of each circuit to be monitored, and mounting the cable load acquisition sensor on the cable body; step 3, detecting grounding current and cable load current, respectively transmitting the grounding current and the cable load current to each monitoring host for signal processing, and transmitting the grounding current and the cable load current to a server through a communication module; step 4, when the grounding circulation signal is judged to have a pulse load, the host broadcasts a control signal, all monitoring hosts acquire the control signal at the same time within preset time, and the synchronization error is within 0.1 s; and 5, analyzing and processing the signals monitored by the multiple hosts to predict whether a fault occurs.
Description
Technical Field
The invention relates to the field of on-line monitoring of cables of a power system, in particular to a Rogowski coil-based on-line monitoring method and device for grounding circulation of a cable sheath.
Background
According to the statistical result of the cable test, the cable fault caused by the damage of the outer sheath due to the external force damage accounts for 58 percent. The single-core XLPE cable metal sheath needs to be reliably grounded at one point during operation, the outer sheath of the power cable is subjected to chemical corrosion, physical damage and the like after being laid violently or operated for a long time to cause insulation damage, so that the metal sheath is exposed to cause multipoint grounding of the metal sheath, and at the moment, the circulation on the metal sheath is obviously increased. The single-core cable metal sheath multipoint earth fault on-line monitoring can be realized by monitoring the metal sheath circulation and the variable quantity thereof in real time. The cable sheath grounding circulation on-line monitoring has the advantages of direct and clear test result, low cost and the like, and is widely applied to cables.
The high-voltage cable line is usually laid in a channel or a tunnel, the laying environment is severe, and the transmission of signals is not facilitated, so that the cable sheath grounding circulation on-line monitoring host is applied to a severe installation environment, and the waterproof, damp-proof and dustproof effects, safety and maintenance convenience of the cable sheath grounding circulation on-line monitoring host are very important. At present, an on-line monitoring host for grounding circulation mainly adopts an open-type current transformer (current type CT) to measure cable load and grounding current. The current type CT adopts the ferrite magnetic core to induce the primary current so as to convert the primary current into the secondary current for output, and the output stability and the precision are relatively high. However, in the practical application process, many problems are highlighted, and even the overall application effect of the cable sheath grounding circulation on-line monitoring host is seriously affected, and the important problems include the following points:
(1) the secondary output end of the current type CT sensor can only be short-circuited but not open-circuited, and secondary suspension voltage is increased due to the increase of secondary end resistance caused by circuit system requirements or circuit faults, so that damage is caused;
(2) the current type CT sensor adopts ferrite as a magnetic core, the larger the transformation ratio is, the higher the required output power is, and the larger the size of the magnetic core is, so that the sensor has larger mass, is difficult to install and is easy to damage a ground wire;
(3) the current type CT sensors for the grounding circulation system are all designed in an open mode, magnetic leakage of the sensors is caused due to improper installation, the sensors are made to vibrate in an attracting mode to generate noise, and the open mode design is difficult to achieve water resistance and rust resistance of the sensors and is not suitable for being applied to severe environments for a long time;
(4) current type CT sensor is bulky, and the shape is single, can't install under the narrow and small monitoring environment in space, and is higher to the application condition requirement.
Therefore, such a ground circulating current sensor greatly limits the application scenarios of sheath circulating current monitoring.
Disclosure of Invention
In order to solve the technical problems, the invention provides a cable sheath fault monitoring device and a method of a multi-Rogowski coil broadcast synchronous signal, which can be used for monitoring the running current and the sheath current of a cable to judge the sheath insulation state of the cable and give an alarm in time.
The technical scheme of the invention is as follows: the utility model provides a many rogowski coil broadcast synchronizing signal's cable sheath fault monitoring devices, includes a plurality of data acquisition sensors, a plurality of monitoring host computer and server:
the plurality of data acquisition sensors comprise a plurality of grounding current acquisition sensors and cable load acquisition sensors, and the primary and secondary transformation ratios of the Rogowski coil in the grounding current acquisition sensors and the cable load acquisition sensors are less than or equal to 1000: 1; each grounding current acquisition sensor corresponds to a cable load acquisition sensor to form a group of monitoring units, and a plurality of groups of monitoring units are arranged in total; the grounding current acquisition sensor is used for acquiring a cable grounding current, and the cable load acquisition sensor is used for acquiring a cable load current;
the monitoring host comprises a box body, a main control module, a power module, a communication module, an alternating current-direct current conversion module and a bottom plate, wherein the main control module, the power module, the communication module, the alternating current-direct current conversion module and the bottom plate are arranged in the box body, and the monitoring host processes and analyzes the grounding current signals and the cable load current collected by the data collection sensor; the detection host is also provided with a monitoring and broadcasting module which is used for analyzing and identifying the grounding circulation change and the correlation between the cable load and the grounding circulation and monitoring a pulse load signal; when the grounding circulation signal is judged to have a pulse load, the monitoring and broadcasting module sends an instruction, and the host broadcasts a control signal to enable all monitoring hosts to simultaneously acquire the control signal within a preset time, wherein the synchronization error is within 0.1 s; the collected grounding current signals and the cable load current are respectively transmitted to each monitoring host for signal processing and are transmitted to a server through a communication module;
the server is used for data acquisition and display, analysis of a grounding circulation result, analysis and processing of signals monitored by the multiple hosts and prediction of whether a fault occurs; the method specifically comprises the following steps: by monitoring the cable circulation signal, the cable load signal and the ratio, the on-line monitoring host machine for the grounding circulation of the cable sheath can give an alarm on the state of the cable sheath in time, and further comprises the steps of cable load and grounding circulation related analysis and historical data check.
Further, the data acquisition sensor comprises a grounding current acquisition sensor and a cable load acquisition sensor, wherein the grounding current acquisition sensor is used for acquiring the grounding current of the cable, and the cable load acquisition sensor is used for acquiring the load current of the cable; the monitoring host comprises a box body, a main control module, a power module, a communication module, an alternating current-direct current conversion module and a bottom plate, wherein the main control module, the power module, the communication module, the alternating current-direct current conversion module and the bottom plate are arranged in the box body, and the monitoring host processes and analyzes the grounding current signals and the cable load current collected by the data collection sensor; the server is used for data acquisition and display, grounding circulation result analysis, cable load and grounding circulation related analysis and historical data viewing.
Furthermore, the data acquisition sensor comprises a sensing unit, a butt joint structure and a data transmission line; the sensing unit is a flexible hollow coil, the flexible hollow coil comprises a wire and a non-ferromagnetic annular framework, the non-ferromagnetic annular framework is provided with an opening and a return line groove in the circumferential direction, the wire inlet wire is uniformly wound on the non-ferromagnetic annular framework, and the wire return line is buried at the bottom of the return line groove; the butt joint structure enables the opening of the non-ferromagnetic annular framework to be in tight butt joint through the butt joint head, leads out the lead inlet wire and the return wire, and then transmits signals through the data transmission line.
Furthermore, the main control module, the power supply module, the communication module and the alternating current/direct current conversion module are mutually independent in structure, and each module is installed on the bottom plate in a plugging mode.
Furthermore, the modes of the communication module for transmitting the cable circulation signal to the server include an optical fiber mode, a WIFI mode and a GPRS mode.
Furthermore, the data acquisition sensor is arranged on the cable body and at the grounding position, the cross section of the opening end is designed in a fully-closed mode, the butt joint structure is completely locked, the outer sheath is fully insulated, and the metal-free part is exposed outside to prevent magnetic leakage and corrosion.
Furthermore, the mainframe box interface and the data line joint adopt the butt joint of waterproof boat plug, can make mainframe box and acquisition sensor independently separately dismantle, conveniently change acquisition sensor.
Furthermore, the cable grounding current and cable load current acquisition sensor can be used for acquiring the working condition when the current is less than 10A; and can collect current of 10A-10000A.
According to another aspect of the present invention, a method for monitoring cable sheath faults of a multiple rogowski coil broadcast synchronization signal is provided, which comprises the following steps:
step 1, setting primary and secondary transformation ratios of Rogowski coils in a grounding current acquisition sensor and a cable load acquisition sensor to be less than or equal to 1000: 1; each grounding current acquisition sensor corresponds to a cable load acquisition sensor to form a group of monitoring units, and a plurality of groups of monitoring units are arranged in total;
According to another aspect of the present invention, a method for estimating insulation aging of an outer sheath of a cable sheath grounding circulating current cable based on a rogowski coil is further provided, which includes the following steps:
step 1, setting primary and secondary transformation ratios of Rogowski coils in a grounding current acquisition sensor and a cable load acquisition sensor to be less than or equal to 1000: 1;
and 5, when the phase difference value is found to be deviated in the monitoring process, judging that the outer sheath of the cable is damaged or the insulation is reduced, performing overall analysis on the collected data of all the grounding circulation monitoring hosts on the same line, automatically and comprehensively analyzing the magnitude of the monitoring current values of all the devices on the line and the phase deviation condition of the devices, automatically and pre-judging the interval of the damaged point of the outer sheath, and timely finding the insulation problem of the cable.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) the open-close type Rogowski coil sensor is used as a data acquisition sensor, is a novel application of the Rogowski coil sensor, is initially applied to grounding circulation detection for China, and does not find similar products in China; the Rogowski coil is wide in measurement frequency band and large in dynamic range, is mainly used for measuring large current, and reaches hundreds of kiloamperes, but the accuracy of measuring grounding current of only a few amperes under the common condition is not high, so that a Rogowski coil sensor is not used as a sensor of a grounding circulation monitoring system.
(2) In order to improve the accuracy of measurement, the invention calibrates a data acquisition sensor, establishes an input current-output voltage parameter correction model, simulates an input-output characteristic curve, restores an input current value through a mathematical model, and controls the transformation ratio of the data acquisition sensor to be not higher than 1000: 1, the accuracy of the measurement is improved. The typical rogowski coil transducer transformation ratio is 10000: 1 or more, if the primary input current is only several amperes, if the primary input-secondary output transformation ratio is larger, the secondary output is smaller, and because the circuit bottom board of the monitoring host has fixed signal bottom noise, if the secondary output signal is too small, the signal bottom noise can be submerged. The transformation ratio of the sensor is 1000: the method can avoid the situations that secondary output signals are too small and submerge in the signal bottom noise of a circuit bottom plate, improve the acquisition precision of the data acquisition sensor, and can be effectively applied to the on-line monitoring of the grounding circulation of the cable sheath.
(3) The accuracy of the cable sheath grounding circulation on-line monitoring device based on the Rogowski coil is not lower than 5% when the current is less than 10A, and the accuracy of the cable sheath grounding circulation on-line monitoring device based on the Rogowski coil is not lower than 1% when the primary current is higher than 10A.
(4) The data acquisition sensor is a flexible Rogowski coil sensor, has high precision and light weight, and can measure current ranging from several amperes to hundreds of kiloamperes; the structure is simple, and direct circuit connection with the measured current is avoided, so that the safety of people and equipment is guaranteed; compared with the traditional grounding circulating current sensor, the grounding circulating current sensor can be randomly arranged on the grounding wire due to lighter weight and cannot damage the cable or the grounding wire.
(5) The host case of the system has small volume, light weight and convenient suspension installation, and the host case interface is butted with the data line connector by adopting a waterproof navigation plug, so that the host case and the sensor can be independently separated, thereby being convenient for later installation and replacement on the one hand, and on the other hand, the host case can normally work in a humid environment for a long time, and meeting the requirement of IP67 protection grade.
(6) The main control module, the power supply module, the communication module and the alternating current-direct current conversion module are all independent functional modules and are installed on the circuit bottom plate in a plug-in type operation mode, and later-period field maintenance and replacement are facilitated.
(7) According to the invention, by monitoring the cable load current, a mechanism for synchronizing the communication of the grounding circulation monitoring host is established, and abnormal data is acquired at the same time, so that the grounding circulation monitoring system can automatically pre-judge the interval of the broken point of the outer sheath, and the accurate analysis of the grounding circulation fault is facilitated.
(8) The grounding circulation monitoring system of the invention realizes real-time monitoring of the phase difference between the grounding current and the composite current of the cable body for the first time, and can find the cable insulation problem in time by monitoring the change condition of the current phase difference.
Drawings
FIG. 1 is a schematic structural diagram of a cable sheath fault monitoring device for broadcasting synchronization signals by Rogowski coil according to the present invention;
FIG. 2 is a schematic diagram of a data acquisition sensor according to the present invention;
fig. 3 is a functional framework diagram of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by a person skilled in the art based on the embodiments of the present invention belong to the protection scope of the present invention without creative efforts.
Fig. 1 shows a schematic structural diagram of a cable sheath fault monitoring device for broadcasting a synchronization signal by multiple rogowski coils. As shown in fig. 1, the device comprises a data acquisition sensor 1, a server 2 and a monitoring host, wherein the monitoring host comprises an outer box 3, a power supply interface 4, an ethernet interface 5, an optical fiber interface 6, a circulation sensor interface 7, a load sensor interface 8, a circuit bottom plate 9, a main control module 10, a power supply module 11, a communication module 12 and an alternating current/direct current conversion module 13.
According to one embodiment of the present invention, the data collection sensor 1 includes a ground current collection sensor for acquiring a cable ground current and a cable load collection sensor for acquiring a cable load current; furthermore, the grounding current acquisition sensor is installed at the direct grounding place or the cross interconnection place of each circuit to be monitored, and the cable load acquisition sensor is installed on the cable body.
The monitoring host is connected with the data acquisition sensor 1 through a circulation sensor interface 7 and a load sensor interface 8. The monitoring host transmits the cable circulation signals collected by the data collecting sensor 1 to the server 2 through the communication module 12.
The data communication mode of the monitoring host and the server 2 can adopt Ethernet connection, optical fiber connection and wireless connection. The optical fiber interface 6 is connected with a network cable to realize data communication. The optical fiber interface 6 connects optical fibers for optical fiber communication.
A circulation sensor connected to circulation sensor interface 7 collects cable circulation signals and a load sensor connected to load sensor interface 8 collects cable load signals. Normally, the ratio of the cable circulation signal to the cable load signal is maintained to fluctuate within a small range, and by monitoring the cable circulation signal, the cable load signal and the ratio, the cable sheath grounding circulation on-line monitoring host can give an alarm on the state of the cable sheath in time.
Fig. 2 shows a schematic diagram of the data acquisition sensor structure. As shown in fig. 2, the data acquisition sensor comprises a sensing unit, a docking structure 16 and a data transmission line 17, wherein the sensing unit comprises an annular framework 14, a return line 15 and an incoming line 18.
The annular framework 14 is provided with an opening and a return line groove in the circumferential direction, the incoming line is uniformly wound on the non-ferromagnetic annular framework, the return line is buried at the bottom of the return line groove, and the incoming line and the return line are led out by the data transmission line.
The butt joint structure enables the annular framework opening to be in tight butt joint through the butt joint head, leads out the lead inlet wire and the return wire, and then transmits signals through the data transmission line.
The sensing unit is connected with the butt joint structure, the opening of the sensing unit is completely sealed through the butt joint structure, the butt joint structure is connected with the data transmission line, and signals are transmitted to the monitoring host through the data transmission line.
According to one embodiment of the invention, the monitoring host processes and analyzes the grounding current signal and the cable load current collected by the data collection sensor;
the server is used for data acquisition and display, grounding circulation result analysis, cable load and grounding circulation related analysis and historical data viewing.
According to one embodiment of the invention, the data acquisition sensor is connected with the monitoring host through the monitoring host box body outside-side navigation plug.
According to an embodiment of the invention, the main control module, the power supply module, the communication module and the alternating current/direct current conversion module are independent from each other in structure, and each module is installed on the bottom plate in a plug-in manner.
According to an embodiment of the present invention, the main control module processes the signal acquired by the data acquisition sensor to obtain an effective value of the current, and preferably, a sensor parameter correction model may be further loaded to correct the signal, thereby improving the signal accuracy.
According to an embodiment of the invention, when the cable sheath grounding circulation on-line monitoring device is used for measurement, a grounding current collecting sensor is arranged at a direct connection place or a cross interconnection place of a monitored line, and a cable load collecting sensor is arranged on a cable body; the grounding current collection sensor detects grounding current, the cable load collection sensor detects cable load current, collected grounding current signals and cable load current are transmitted to the monitoring host to be processed and transmitted to the server through the communication module, and analysis and identification are carried out on grounding circulation change and the correlation between cable load and grounding circulation.
The invention provides a method for carrying out on-line monitoring on the grounding circulation of a cable sheath under the conditions of narrow space and complex environment.
The invention provides a method for safely installing and replacing a current acquisition sensor under the condition of cable load operation.A traditional current type CT sensor adopts ferrite as a magnetic core, an iron core at an opening is exposed outside and cannot be tightly attached due to the limitation of a grinding process, and the iron core can vibrate and is easy to have magnetic leakage and rust due to the electromagnetic acting force; the data acquisition sensor is installed on the cable body and the grounding part, and the cross section of the opening end is designed in a totally-enclosed manner, so that the butt joint structure can be completely locked, the outer sheath is completely insulated, no metal part is exposed outside, and the cable can not be subjected to magnetic leakage and corrosion after long-term use, and the safety is improved.
According to an embodiment of the present invention, a method for accurately detecting a small current of several amperes of a cable is provided, where a measured current is in direct proportion to an output voltage of a sensor, and if the measured current is small and a transformation ratio of the sensor is too large, a voltage output signal may be too small and submerged in noise floor to be unrecognizable, and preferably, a parameter correction model may be established for a sensor skeleton, a number of turns of a winding, and a terminal resistor, so as to simulate an input/output characteristic curve, thereby realizing that the transformation ratio of the data acquisition sensor is not higher than 1000: 1, the small current of several amperes can be accurately detected, and the detection range and precision are improved.
According to the monitoring device provided by the invention, in the online monitoring method of the grounding loop, the interference on other monitoring equipment (such as partial discharge monitoring equipment) can not be generated under the comprehensive monitoring system of the smart grid, and in the current data acquisition and transmission process, the sensor and the host can not generate electromagnetic interference noise and can not influence other online monitoring equipment.
According to an embodiment of the invention, a method for monitoring the fault of the cable sheath of the broadcast synchronous signal of the multiple Rogowski coils is provided, so that the short-time synchronous acquisition among devices is realized, the analysis errors caused by inaccurate measurement of the grounding circulation and asynchronous line data under the condition of short-time pulse load of the cable are solved, the grounding circulation fault is accurately analyzed, and the automatic analysis accuracy is improved; the method comprises the steps that generally, a ground circulation monitoring host acquires data at certain intervals, the acquired data are not always at the same time, if pulse load occurs, some monitoring hosts possibly acquire signals, some monitoring hosts do not acquire signals, and data for ground circulation fault analysis are disordered to a certain extent. Specifically, the method comprises the following steps:
step 1, setting primary and secondary transformation ratios of Rogowski coils in a grounding current acquisition sensor and a cable load acquisition sensor to be less than or equal to 1000: 1; each grounding current acquisition sensor corresponds to a cable load acquisition sensor to form a group of monitoring units, and a plurality of groups of monitoring units are arranged in total;
According to another embodiment of the invention, the estimation method for the insulation aging of the outer sheath of the cable sheath grounding circulating current cable based on the rogowski coil is further provided, the grounding circulating current and the composite current amplitude of the cable body are monitored phase by phase, the phase difference between the grounding current and the composite current of the cable body is monitored in real time, the initial phase difference is recorded during initial equipment installation, when the deviation of the phase difference is found in the monitoring process, the outer sheath of the cable can be judged to be damaged or reduced in insulation, the collected data of all grounding circulating current monitoring hosts on the same line are analyzed comprehensively, the magnitude of the monitored current values of all equipment on the line and the phase deviation conditions of the outer sheath of the equipment are automatically analyzed, the section where the damaged point occurs can be automatically pre-judged, and the insulation problem of the cable can be found in. The method specifically comprises the following steps:
step 1, setting primary and secondary transformation ratios of Rogowski coils in a grounding current acquisition sensor and a cable load acquisition sensor to be less than or equal to 1000: 1;
and 5, when the phase difference value is found to be deviated in the monitoring process, judging that the outer sheath of the cable is damaged or the insulation is reduced, performing overall analysis on the collected data of all the grounding circulation monitoring hosts on the same line, automatically and comprehensively analyzing the magnitude of the monitoring current values of all the devices on the line and the phase deviation condition of the devices, automatically and pre-judging the interval of the damaged point of the outer sheath, and timely finding the insulation problem of the cable.
Fig. 3 is a functional framework diagram of the present invention, and the server can implement data acquisition and display, ground circulation result analysis, cable load and ground circulation related analysis, and historical data viewing functions.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present invention as described in the specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A cable sheath fault monitoring device for broadcasting synchronous signals by multiple Rogowski coils comprises multiple data acquisition sensors, multiple monitoring hosts and a server; the method is characterized in that:
the plurality of data acquisition sensors comprise a plurality of grounding current acquisition sensors and cable load acquisition sensors, and the primary and secondary transformation ratios of the Rogowski coil in the grounding current acquisition sensors and the cable load acquisition sensors are less than or equal to 1000: 1; each grounding current acquisition sensor corresponds to a cable load acquisition sensor to form a group of monitoring units, and a plurality of groups of monitoring units are arranged in total; the grounding current acquisition sensor is used for acquiring a cable grounding current, and the cable load acquisition sensor is used for acquiring a cable load current;
the monitoring host comprises a box body, a main control module, a power module, a communication module, an alternating current-direct current conversion module and a bottom plate, wherein the main control module, the power module, the communication module, the alternating current-direct current conversion module and the bottom plate are arranged in the box body, and the monitoring host processes and analyzes the grounding current signals and the cable load current collected by the data collection sensor; the detection host is also provided with a monitoring and broadcasting module which is used for analyzing and identifying the grounding circulation change and the correlation between the cable load and the grounding circulation and monitoring a pulse load signal; when the grounding circulation signal is judged to have a pulse load, the monitoring and broadcasting module sends an instruction, and the host broadcasts a control signal to enable all monitoring hosts to simultaneously acquire the control signal within a preset time, wherein the synchronization error is within 0.1 s; the collected grounding current signals and the cable load current are respectively transmitted to each monitoring host for signal processing and are transmitted to a server through a communication module;
the server is used for data acquisition and display, analysis of a grounding circulation result, analysis and processing of signals monitored by the multiple hosts and prediction of whether a fault occurs; the method specifically comprises the following steps: by monitoring the cable circulation signal, the cable load signal and the ratio, the on-line monitoring host machine for the grounding circulation of the cable sheath can give an alarm on the state of the cable sheath in time, and further comprises the steps of cable load and grounding circulation related analysis and historical data check.
2. The apparatus for monitoring the fault of the cable sheath of the broadcasting synchronous signals of the multiple rogowski coils in claim 1, wherein:
the data acquisition sensor comprises a grounding current acquisition sensor and a cable load acquisition sensor, wherein the grounding current acquisition sensor is used for acquiring the grounding current of a cable, and the cable load acquisition sensor is used for acquiring the load current of the cable; the monitoring host comprises a box body, a main control module, a power module, a communication module, an alternating current-direct current conversion module and a bottom plate, wherein the main control module, the power module, the communication module, the alternating current-direct current conversion module and the bottom plate are arranged in the box body, and the monitoring host processes and analyzes the grounding current signals and the cable load current collected by the data collection sensor; the server is used for data acquisition and display, grounding circulation result analysis, cable load and grounding circulation related analysis and historical data viewing.
3. The apparatus for monitoring the fault of the cable sheath of the broadcasting synchronous signals of the multiple rogowski coils in claim 1, wherein:
the data acquisition sensor comprises a sensing unit, a butt joint structure and a data transmission line; the sensing unit is a flexible hollow coil, the flexible hollow coil comprises a wire and a non-ferromagnetic annular framework, the non-ferromagnetic annular framework is provided with an opening and a return line groove in the circumferential direction, the wire inlet wire is uniformly wound on the non-ferromagnetic annular framework, and the wire return line is buried at the bottom of the return line groove; the butt joint structure enables the opening of the non-ferromagnetic annular framework to be in tight butt joint through the butt joint head, leads out the lead inlet wire and the return wire, and then transmits signals through the data transmission line.
4. The apparatus for monitoring the fault of the cable sheath of the broadcasting synchronous signals of the multiple rogowski coils in claim 1, wherein:
the main control module, the power module, the communication module and the alternating current-direct current conversion module are mutually independent in structure, and each module is installed on the bottom plate in a plugging mode.
5. The apparatus for monitoring the fault of the cable sheath of the broadcasting synchronous signals of the multiple rogowski coils in claim 1, wherein: the communication module transmits the cable circulation signal to the server in modes of optical fiber, WIFI and GPRS.
6. The apparatus for monitoring the fault of the cable sheath of the broadcasting synchronous signals of the multiple rogowski coils in claim 1, wherein: the data acquisition sensor is installed on the cable body and the grounding part, the cross section of the opening end is designed in a totally-enclosed manner, the butt joint structure is completely locked, the outer sheath is completely insulated, and the metal-free part is exposed outside to prevent magnetic leakage and corrosion.
7. The apparatus for monitoring the fault of the cable sheath of the broadcasting synchronous signals of the multiple rogowski coils in claim 1, wherein: the mainframe box interface adopts waterproof boat plug butt joint with the data line joint, can make mainframe box and acquisition sensor independently separately dismantle, conveniently changes acquisition sensor.
8. The apparatus for monitoring the fault of the cable sheath of the broadcasting synchronous signals of the multiple rogowski coils in claim 1, wherein: the cable grounding current and cable load current acquisition sensor can be used for acquiring the working condition when the current is less than 10A; and can collect current of 10A-10000A.
9. A cable sheath fault monitoring method for broadcasting synchronous signals by multiple Rogowski coils is characterized by comprising the following steps:
step 1, setting primary and secondary transformation ratios of Rogowski coils in a grounding current acquisition sensor and a cable load acquisition sensor to be less than or equal to 1000: 1; each grounding current acquisition sensor corresponds to a cable load acquisition sensor to form a group of monitoring units, and a plurality of groups of monitoring units are arranged in total;
step 2, mounting the grounding current acquisition sensor at the direct connection place or the cross interconnection place of each circuit to be monitored, and mounting the cable load acquisition sensor on the cable body;
step 3, a grounding current acquisition sensor detects grounding current, a cable load acquisition sensor detects cable load current, and acquired grounding current signals and cable load current are respectively transmitted to each monitoring host for signal processing and are transmitted to a server through a communication module;
step 4, analyzing and identifying the grounding circulation change and the correlation between the cable load and the grounding circulation by the monitoring host; when the grounding circulation signal is judged to have a pulse load, the host broadcasts a control signal, all monitoring hosts acquire the control signal at the same time within preset time, and the synchronization error is within 0.1 s;
step 5, analyzing and processing signals monitored by a plurality of hosts to predict whether a fault occurs; the method specifically comprises the following steps: by monitoring the cable circulation signal, the cable load signal and the ratio, the cable sheath grounding circulation on-line monitoring host machine alarms the state of the cable sheath in time.
10. A method for estimating insulation aging of an outer protective layer of a cable sheath grounding circulating cable based on a Rogowski coil is characterized by comprising the following steps:
step 1, setting primary and secondary transformation ratios of Rogowski coils in a grounding current acquisition sensor and a cable load acquisition sensor to be less than or equal to 1000: 1;
step 2, mounting the grounding current acquisition sensor at the direct connection place or the cross interconnection place of each circuit to be monitored, and mounting the cable load acquisition sensor on the cable body;
step 3, a grounding current acquisition sensor detects grounding current, a cable load acquisition sensor detects cable load current, and the acquired grounding current signal and the cable load current are respectively transmitted to a monitoring host for signal processing and are transmitted to a server through a communication module;
step 4, monitoring the phase difference between the grounding current and the composite current of the cable body in real time by monitoring the grounding circulation and the composite current amplitude of the cable body phase by phase, and comparing the phase difference with the initial phase difference recorded during initial equipment installation;
and 5, when the phase difference value is found to be deviated in the monitoring process, judging that the outer sheath of the cable is damaged or the insulation is reduced, performing overall analysis on the collected data of all the grounding circulation monitoring hosts on the same line, automatically and comprehensively analyzing the magnitude of the monitoring current values of all the devices on the line and the phase deviation condition of the devices, automatically and pre-judging the interval of the damaged point of the outer sheath, and timely finding the insulation problem of the cable.
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Application publication date: 20201211 |