CN111638425A - High-voltage cable fault positioning device - Google Patents
High-voltage cable fault positioning device Download PDFInfo
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- CN111638425A CN111638425A CN202010684490.7A CN202010684490A CN111638425A CN 111638425 A CN111638425 A CN 111638425A CN 202010684490 A CN202010684490 A CN 202010684490A CN 111638425 A CN111638425 A CN 111638425A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/58—Testing of lines, cables or conductors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
Abstract
The invention discloses a high-voltage cable fault positioning device which comprises a monitoring alarm module, a fan box transformer substation unit, a switch cabinet unit and a plurality of local acquisition units arranged on a high-voltage cable; the switch cabinet unit is connected with a high-voltage cable, and the fan box transformer unit is connected with a plurality of local acquisition units and a monitoring alarm module; the switch cabinet unit is used for forming a zero-sequence current path and acquiring zero-sequence voltage when a system fails; the local acquisition unit is used for acquiring zero sequence current and sending the zero sequence current to the fan box transformer substation unit; the fan box transformer unit is used for supplying power to the on-site acquisition unit and sending the zero sequence current to the monitoring alarm module; and the monitoring alarm module is used for comparing the acquired zero sequence current to determine the position of the ground fault of the high-voltage cable. According to the invention, the zero sequence current generated when the system is abnormal is acquired through the local acquisition unit, and the fault position is rapidly and accurately determined, so that maintenance personnel is prompted to carry out fault removal in time, and the power failure loss caused by the ground fault is reduced.
Description
Technical Field
The invention relates to the field of high-voltage power transmission, in particular to a high-voltage cable fault positioning device.
Background
At present, a high-voltage power transmission line mainly takes an overhead line as a main part, but in medium-voltage systems such as mountain wind power plants and urban power distribution networks, cables are often adopted to replace the overhead line in order to meet the requirements of reducing the probability of lightning strikes, passing through a heavily-iced area, being attractive in the whole urban area and the like. With the increase of cable lines, the probability of the cable lines failing is also increasing, so that the stability of a power system is seriously affected, and huge economic losses are brought to enterprises on a power generation side and a power utilization side. Therefore, when a certain section of the cable line breaks down, the fault point on the cable line needs to be found out quickly, accurately and effectively, so that the system stability is improved, and the economic loss caused by the fault is reduced.
The existing cable line fault detection mainly comprises the steps of fault diagnosis, rough measurement point and accurate fixed point, and the judgment mode is usually an acoustic, optical and thermal method, a resistance, capacitance bridge method, a pulse method and the like. The fault position is searched by adopting the mode, a large amount of workload is required to support, a large amount of time is consumed, a plurality of detection modes are required to be adopted to improve the detection precision, and the fault position determined on the direct-buried cable line and the actual fault position have large deviation, so that the detection precision is greatly reduced.
Disclosure of Invention
The invention mainly aims to provide a high-voltage cable fault positioning device, and aims to solve the problems that the existing detection mode is long in time consumption and low in detection precision.
In order to achieve the aim, the invention provides a high-voltage cable fault positioning device which comprises a monitoring alarm module, a fan box transformer substation unit, a switch cabinet unit and a plurality of local acquisition units arranged on a high-voltage cable;
the switch cabinet unit is connected with a high-voltage cable, the fan box transformer substation unit is connected with a plurality of on-site acquisition units, and the fan box transformer substation unit is also connected with the monitoring alarm module;
the switch cabinet unit is used for forming a zero-sequence current path when the high-voltage cable has a ground fault;
the local acquisition unit is used for acquiring zero sequence current when the high-voltage cable has a ground fault and sending the acquired zero sequence current to the fan box transformer substation unit;
the fan box transformer unit is used for supplying power to the on-site acquisition unit and sending the received zero sequence current to the monitoring alarm module;
and the monitoring alarm module is used for comparing the zero sequence currents acquired by the plurality of on-site acquisition units to determine the position of the ground fault of the high-voltage cable.
Optionally, the in-situ collection unit includes a zero sequence current transformer sleeved on the high-voltage cable;
the fan box transformer unit is used for receiving zero sequence currents detected by the plurality of zero sequence current transformers when the high-voltage cable has a ground fault and sending the received plurality of zero sequence currents to the monitoring alarm module;
the monitoring and alarming module is used for comparing zero sequence currents detected by every two adjacent zero sequence current transformers, and when detecting that the zero sequence currents detected by the two adjacent zero sequence current transformers are different, determining that the position of the ground fault of the high-voltage cable is between the two adjacent zero sequence current transformers.
Optionally, the on-site collection unit includes two zero sequence current transformers and a zero sequence current collection module, the high voltage cable includes a plurality of intermediate connectors, and the plurality of on-site collection units correspond to the plurality of intermediate connectors one to one;
two zero sequence current transformers are respectively sleeved at two ends of the middle joint, and the zero sequence current acquisition module is respectively connected with the two zero sequence current transformers;
the zero-sequence current acquisition module is used for calculating the difference value of the zero-sequence currents detected by the two zero-sequence current transformers and sending the zero-sequence currents detected by the two zero-sequence current transformers and the difference value calculation result to the monitoring alarm module through the fan box transformer unit;
and the monitoring alarm module is used for determining that the intermediate joint corresponding to the zero sequence current acquisition module has a ground fault when the difference calculation result sent by the zero sequence current acquisition module is not zero.
Optionally, the plurality of zero sequence current transformers are encoded according to the sequence from the system end to the power generation end of the high voltage cable, the switch cabinet unit is connected with the system end of the high voltage cable, and the switch cabinet unit comprises a voltage transformer and a grounding complete equipment;
the grounding conversion complete equipment is used for forming a zero sequence current path when the high-voltage cable has a grounding fault;
the voltage transformer is used for detecting and obtaining zero sequence voltage when the high-voltage cable has a ground fault and sending the zero sequence voltage to the monitoring alarm module;
the monitoring and alarming module is used for comparing angles of all zero-sequence currents and the zero-sequence voltage according to a coding sequence when receiving the zero-sequence currents sent by the plurality of zero-sequence current transformers, and determining the position of the ground fault of the high-voltage cable between the zero-sequence current transformer with the largest coding in the leading zero-sequence voltage and the zero-sequence current transformer with the smallest coding in the lagging zero-sequence voltage when the angle of the zero-sequence currents is changed from the leading zero-sequence voltage to the lagging zero-sequence voltage.
Optionally, the monitoring and alarming module is further configured to perform angle comparison on two zero-sequence currents detected by two adjacent zero-sequence current transformers, and when an angle difference between the two detected zero-sequence currents is 180 °, determine that a ground fault position of the high-voltage cable is located between the two corresponding adjacent zero-sequence current transformers.
Optionally, the switchgear unit further comprises a standard zero sequence current transformer;
the standard zero sequence current transformer is used for detecting and obtaining standard zero sequence current when the high-voltage cable has a ground fault;
the monitoring and alarming module is further configured to compare all zero-sequence currents with a standard zero-sequence current according to a coding sequence, divide all zero-sequence current transformers into a first transformer group with zero-sequence currents having the same magnitude as the standard zero-sequence currents and a second transformer group with zero-sequence currents having different magnitudes from the standard zero-sequence currents, and determine a position of a ground fault of the high-voltage cable between a zero-sequence current transformer with a largest coding in the first transformer group and a zero-sequence current transformer with a smallest coding in the second transformer group.
Optionally, the fan box transformer unit includes a fan step-up transformer and a communication management module, the communication management module is connected to the plurality of zero-sequence current acquisition modules, and the fan step-up transformer is connected to the communication module and the plurality of zero-sequence current acquisition modules;
the fan step-up transformer is used for supplying power to the communication management module and the plurality of zero-sequence current acquisition modules;
and the communication management module is used for receiving the two zero-sequence currents and the difference value calculation result sent by the zero-sequence current acquisition module and sending the result to the monitoring alarm module.
Optionally, the monitoring alarm module comprises a data processing module and an alarm module, and the data processing module is respectively connected with the fan box transformer substation unit and the alarm module;
the data processing module is used for receiving the zero sequence currents sent by all the zero sequence current acquisition modules and determining the ground fault position of the high-voltage cable according to the zero sequence current transformer which detects the abnormal zero sequence current;
the alarm module is used for sending an alarm signal when the data processing module determines the position of the ground fault of the high-voltage cable, wherein the alarm signal is an acoustic signal and/or an optical signal.
Optionally, the number of the fan box transformer substation units is multiple, the communication management module of each fan box transformer substation unit is connected with the plurality of local acquisition units through a bus, the communication management modules of the plurality of fan box transformer substation units form an optical fiber ring network, and the data processing module is connected to the optical fiber ring network.
Optionally, the warning module includes a plurality of LED lamps corresponding to the local acquisition units;
and the alarm module is also used for lighting the corresponding LED lamp corresponding to the local acquisition unit when the data processing module determines the ground fault position of the high-voltage cable.
According to the invention, the plurality of on-site acquisition units are arranged on the high-voltage cable, and when the zero-sequence current is generated due to the occurrence of the ground fault of the high-voltage cable, the zero-sequence current flowing through the on-site acquisition units is acquired. Because the zero sequence currents at the left end and the right end of the fault point are different, the monitoring alarm module can quickly and accurately determine the ground fault position of the high-voltage cable according to the setting position of the on-site acquisition unit by comparing the sizes of the zero sequence currents acquired by the on-site acquisition unit, thereby prompting related maintenance personnel to go to the ground fault position in time for fault removal and reducing power failure loss caused by the ground fault of the high-voltage cable.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a schematic block diagram of an embodiment of a high-voltage cable fault location device according to the present invention;
FIG. 2 is a schematic diagram of a refinement module of the embodiment of FIG. 1;
FIG. 3 is a schematic diagram of the connection of the on-site acquisition unit according to an embodiment of the present invention;
fig. 4 is a schematic circuit diagram of a switch cabinet unit in the case of ground fault according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of zero sequence current of a fault point according to an embodiment of the present invention;
fig. 6 is a schematic connection diagram of a standard zero sequence current transformer in an embodiment of the present invention;
fig. 7 is a schematic connection diagram of a communication management module according to an embodiment of the present invention.
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) |
| 10 | In-situ collection unit | CT | Zero sequence |
| 20 | Monitoring alarm module | CT101 | Standard zero sequence |
| 21 | Alarm module | IO/ADC | Zero sequence |
| 30 | Switch cabinet unit | T2 | |
| 40 | Fan box transformer substation unit | DPU | |
| 50 | High-voltage cable | DT | Data processing module |
| T1 | Grounding becomes complete equipment | TV | Voltage transformer |
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the 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, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The invention provides a high-voltage cable fault positioning device which is used for quickly and accurately determining a fault position when a high-voltage cable has a ground fault.
Referring to fig. 1, in an embodiment, the fault location device for a high voltage cable 50 includes a monitoring alarm module 20, a blower box transformer unit 40, a switch cabinet unit 30, and a plurality of local acquisition units 10 disposed on the high voltage cable 50. The switch cabinet unit 30 is connected with a high-voltage cable 50, the fan box transformer substation unit 40 is connected with a plurality of local acquisition units 10, and the fan box transformer substation unit 40 is further connected with the monitoring alarm module 20. The switch cabinet unit 30 and the monitoring alarm module 20 may be disposed in a 35kV distribution room, and the blower box transformer unit 40 may be disposed on a blower platform.
The two ends of the high voltage cable 50 are connected to the power generation end and the system end, respectively. The switch cabinet unit 30 is disposed at a system end side of the high-voltage cable 50, and when the high-voltage cable 50 transmits power normally, the three-phase current and the three-phase voltage are in a symmetrical and balanced state, and at this time, the zero-sequence current is zero. When a ground fault occurs at a certain position of the high voltage cable 50, the system will generate a zero sequence current by grounding through the switch cabinet unit 30, thereby forming a zero sequence current path. When a zero sequence circuit is generated due to single-phase grounding of the high-voltage cable 50, the plurality of local acquisition units 10 arranged on the high-voltage cable 50 can acquire the zero sequence current flowing at the arrangement positions thereof, and transmit the acquired zero sequence current to the fan box transformer unit 40. The fan box transformer unit 40 can be connected with a plurality of local acquisition units 10 to supply power so that the local acquisition units can acquire zero sequence current, and transmit the received zero sequence current acquired by the local acquisition units 10 to the monitoring alarm module 20.
The monitoring alarm module 20 can receive the zero sequence current collected by all the local collection units 10 on the high voltage cable 50 when the ground fault occurs to the high voltage cable 50. As shown in fig. 4 to 5, if a side of the high voltage cable 50 close to the system end is defined as a side a, a side close to the power generation end is defined as B, and a position of the high voltage cable 50 where a ground fault occurs is defined as K, the zero sequence current of the fault point K is composed of iA, iB, and i0, where iA is the zero sequence current of the high voltage cable 50, where the system end a flows to the fault point K, iB is the zero sequence current of the high voltage cable 50, where the power generation end B flows to the fault point K, i0 is the zero sequence current of the fault point K flowing to the ground, and iA + iB is 3i0, where iA and iB are different in size and opposite in direction, and iA is much larger than iB. It can be understood that the magnitude of the zero sequence current collected by each local collection unit 10 between the system terminals a and K on the high voltage cable 50 is iA, and the magnitude of the zero sequence current collected by each local collection unit 10 between the power generation terminals B and K is iB.
After receiving the zero sequence currents collected by all the on-site collection units 10, the monitoring alarm module 20 compares the magnitudes of the zero sequence currents to determine the on-site collection unit 10 closest to the ground fault position, thereby accurately positioning the ground fault position of the high-voltage cable 50.
In the present embodiment, by providing a plurality of local collecting units 10 on the high voltage cable 50, when the high voltage cable 50 generates a zero sequence current due to a ground fault, the local collecting units 10 collect the flowing zero sequence current. Because the zero sequence currents at the left end and the right end of the fault point are different, the monitoring alarm module 20 can determine the ground fault position of the high-voltage cable 50 according to the setting position of the on-site acquisition unit 10 by comparing the magnitude of the zero sequence currents acquired by the on-site acquisition unit 10, so that related maintenance personnel can be prompted to go to the ground fault position in time for fault removal, and the power failure loss caused by the ground fault of the high-voltage cable 50 is reduced.
Referring to fig. 2 to 3, the local collecting unit 10 may include a zero sequence current transformer CT sleeved on the high voltage cable 50, and when the high voltage cable 50 generates a zero sequence current due to a ground fault, the zero sequence current flowing through the cable may be collected by the zero sequence current transformer CT. The fan box transformer unit 40 may be connected to a plurality of local acquisition units 10 including a zero sequence current transformer CT nearby to receive a zero sequence current detected by the plurality of zero sequence current transformers CT when a ground fault occurs in the high voltage cable 50. After receiving the zero sequence current, the fan box transformer unit 40 sends a plurality of zero sequence currents to the alarm module. It should be noted that, a plurality of zero sequence current transformers CT may be encoded in advance according to the transmission line of the high voltage cable 50 in the sequence from the system end to the power generation end, and two adjacent zero sequence current transformers CT are also adjacently sleeved on the high voltage cable 50.
After receiving the zero sequence currents collected by all the zero sequence current transformers CT, the monitoring alarm module 20 may compare the zero sequence currents detected by two adjacent zero sequence current transformers CT according to the codes, and if the zero sequence currents detected by two adjacent zero sequence current transformers CT are the same, the two adjacent zero sequence current transformers CT are located on the same side of the ground fault position on the high-voltage cable 50; if the zero-sequence currents detected by two adjacent zero-sequence current transformers CT are different in magnitude, the two adjacent zero-sequence current transformers CT are located on two sides of the ground fault position on the high-voltage cable 50, that is, the ground fault position of the high-voltage cable 50 is between the two zero-sequence current transformers CT. The ground fault position of the high-voltage cable 50 can be determined quickly and accurately according to the codes and the corresponding installation positions of the two zero sequence circuit transformers.
In an embodiment, as shown in fig. 3, to provide a zero-sequence current detection manner for the ground fault of the intermediate joint, each of the local acquisition units 10 may include two zero-sequence current transformers CT and a zero-sequence current acquisition module IO/ADC connected to the two zero-sequence current transformers CT. The high voltage cable 50 connects the power generation end with the system end through a plurality of intermediate joints and cables. The number of in situ acquisition units 10 may correspond one-to-one to the number of intermediate joints. Namely, the left end and the right end of each intermediate joint are respectively sleeved with two zero sequence current transformers CT which are connected with a zero sequence current acquisition module IO/ADC. When the high-voltage cable 50 generates a zero-sequence current due to a ground fault, the two zero-sequence current transformers CT on the two sides of the middle joint can respectively collect the zero-sequence current and send the zero-sequence current to the zero-sequence current collection module IO/ADC. It can be understood that if the zero-sequence currents collected by the two zero-sequence current transformers CT are the same, the middle joint is not a fault point K where the high-voltage cable 50 has a ground fault; if the zero sequence currents acquired by the two zero sequence current transformers CT are different, the middle joint is the fault point K. The zero sequence current acquisition module IO/ADC calculates a difference value of zero sequence currents detected by the two zero sequence current transformers CT, and sends the zero sequence currents detected by the two zero sequence current transformers CT and a difference value calculation result to the fan box transformer unit 40, the fan box transformer unit 40 continues to forward the difference value calculation result to the monitoring alarm module 20, and when the difference value calculation result of the monitoring alarm module 20 is zero, the middle joint corresponding to the zero sequence current acquisition module IO/ADC which sends the zero result is determined not to be a fault point K; and when the difference value calculation result is not zero, the intermediate joint corresponding to the zero sequence current acquisition module IO/ADC which sends the non-zero result can be determined to be the ground fault position.
Referring to fig. 2, in an embodiment, a zero sequence voltage angle comparison method for a cable line ground fault is provided, in which a plurality of zero sequence current transformers CT sleeved on a high voltage cable 50 are encoded according to a sequence from a system end to a power generation end of the high voltage cable 50. The switchgear cell 30 is connected to the system side of the high voltage cable 50, and the switchgear cell 30 may include a voltage transformer TV and a ground complete T1. Wherein the ground-to-ground complete equipment T1 may form a zero-sequence current path through the neutral point when a ground fault occurs in the high voltage cable 50. The inductance transformer can detect the amplitude and the angle of the zero sequence voltage U0 when the high-voltage cable 50 has a ground fault through the open triangle. It can be understood that the zero sequence current transformer CT is also capable of detecting the amplitude and angle of the zero sequence current.
The monitoring and warning module 20 may compare all the zero-sequence currents with the zero-sequence voltages one by one according to the encoding sequence when receiving the zero-sequence currents sent by the plurality of zero-sequence current transformers CT, and it can be understood that the angle of the zero-sequence current iA between the fault point K and the system end a is earlier than the angle of the zero-sequence voltage, and the angle of the zero-sequence current iB between the fault point K and the power generation end B is later than the angle of the zero-sequence voltage. When the zero sequence current is compared with the zero sequence voltage one by one according to the sequence, if the angle of the detected zero sequence current is changed from the leading zero sequence voltage to the lagging zero sequence voltage, the fault point K between the two changed zero sequence current transformers CT can be determined. It can be understood that, in the zero sequence current transformer CT of leading zero sequence voltage, the zero sequence current transformer CT with the largest coding is the zero sequence current transformer CT closest to the fault point K, and similarly, in the zero sequence current transformer CT of lagging zero sequence voltage, the zero sequence current transformer CT with the smallest coding is the zero sequence current transformer CT closest to the fault point K. After the corresponding positions of the two zero sequence current transformers CT on the high voltage cable 50 are determined according to the codes of the two zero sequence current transformers CT, it can be determined that the fault point K is located on the cable line between the two zero sequence current transformers CT.
It should be noted that the angle of zero-sequence current iA between fault point K and system end a leading the zero-sequence voltage U0 is about 110 °, and the angle of zero-sequence current iB between fault point K and power generation end B lagging the zero-sequence voltage U0 is about 70 °, i.e. the angle between iA and iB differs by 180 °.
In an embodiment, a zero sequence current detection method during a cable line ground fault is provided, and the monitoring alarm module 20 may compare angles of two zero sequence currents detected by two adjacent zero sequence current transformers CT after receiving the zero sequence currents collected by all encoded zero sequence current transformers CT. If the angles of the two zero-sequence currents are the same, the two zero-sequence current transformers CT are positioned on the same side of a fault point K; if the directions of the two zero-sequence currents are opposite, that is, the angle difference between the two zero-sequence currents is 180 degrees, it can be determined that the two zero-sequence current transformers CT are located on the two sides of the fault point K, and after the corresponding positions of the two zero-sequence current transformers CT on the high-voltage cable 50 are determined according to the codes of the two zero-sequence current transformers CT, it can be determined that the fault point K is located on the cable line between the two zero-sequence current transformers CT.
It can be understood that the two zero-sequence currents received by the zero-sequence current acquisition module IO/ADC are analog signals, and the zero-sequence current acquisition module IO/ADC may convert the two zero-sequence currents and the difference calculation result from the analog signals into digital signals and send the digital signals to the fan box transformer unit 40.
Referring to fig. 2 to 6 together, in an embodiment, a detection method based on a standard zero sequence current in a cable line ground fault is provided, and the switch cabinet unit 30 further includes a standard zero sequence current transformer CT101, where the standard zero sequence current transformer CT101 is disposed on an outlet side of the system end a of the high voltage cable 50 and can detect the standard zero sequence current when the high voltage cable 50 has a ground fault. The monitoring alarm module 20 may also compare all the zero-sequence currents with the standard zero-sequence currents according to the coding sequence, and during the change process from small to large of the coding, the zero-sequence current transformer CT is more and more far away from the system end a and close to the fault point K. When the zero sequence current transformer CT is positioned between the system end A and the fault point K, the size and the direction of the collected zero sequence current are the same as those of the standard zero sequence current, and the size and the direction of the collected zero sequence current of the zero sequence current transformer CT positioned between the fault point K and the power generation end B are different from those of the standard zero sequence current. If all the zero-sequence current transformers CT are divided into a first transformer group with the same size as the standard zero-sequence current and a second transformer group with the different size from the standard zero-sequence current according to whether the size of the zero-sequence current transformers CT is the same as the standard zero-sequence current, the position between the zero-sequence current transformer CT with the largest coding in the first transformer group and the zero-sequence current transformer CT with the smallest coding in the second transformer group is the ground fault position of the high-voltage cable 50.
It should be noted that when n intermediate connectors exist on the high-voltage cable 50, zero sequence current transformers CT, that is, 2n zero sequence current transformers CT, are respectively disposed at two ends of each intermediate connector, and a standard zero sequence current transformer CT101 is further disposed on the outgoing line side of the system end a of the high-voltage cable 50. Therefore, 2n +1 zero-sequence current transformers CT can be arranged on a high-voltage cable 50 with n intermediate connectors.
Further, the fan box transformer unit 40 may include a fan step-up transformer T2 and a communication management module DPU, where the communication management module DPU is connected to the plurality of zero-sequence current acquisition modules IO/ADC, and the fan step-up transformer T2 is connected to the communication module and the plurality of zero-sequence current acquisition modules IO/ADC; the fan step-up transformer T2 can supply power to a plurality of zero sequence current acquisition modules IO/ADC and a communication management module DPU connected with the fan step-up transformer, so that the zero sequence current acquisition modules IO/ADC can perform difference value calculation on two zero sequence currents after acquiring the zero sequence currents acquired by the two zero sequence current transformers CT and send the difference value calculation result and the two zero sequence currents to the communication management module DPU. The communication management module DPU may forward the two zero-sequence currents and the difference calculation result sent by the zero-sequence current acquisition module IO/ADC to the monitoring alarm module 20 after receiving the two zero-sequence currents and the difference calculation result.
Further, the monitoring alarm module 20 may include a data processing module DT and an alarm module 21, where the data processing module DT is connected to the fan box transformer unit 40 and the alarm module 21, respectively. The data processing module DT can receive the zero sequence currents sent by all the zero sequence current acquisition modules IO/ADC on the high-voltage cable 50, and determine the ground fault position of the high-voltage cable 50 according to the zero sequence current transformer CT corresponding to the zero sequence current with abnormal changes in the magnitude, direction, and the like of the zero sequence current. For example, when the zero sequence current changes in magnitude or direction, the cable line between the zero sequence current transformer CT before the change and the zero sequence current transformer CT after the change is the ground fault position of the high-voltage cable 50. The alarm module 21 may send an alarm signal to prompt the relevant maintenance personnel to perform fault removal in time when the data processing module DT determines the ground fault location of the high voltage cable 50, so as to reduce the fault loss. It is understood that the alarm signal emitted by the alarm module 21 may be an acoustic signal, an optical signal or an acousto-optic signal. Optionally, the alarm module 21 may be provided with a plurality of LED lamps corresponding to the on-site collection unit 10, and when the data processing module DT determines the ground fault location of the high-voltage cable 50, the alarm module 21 may be controlled to light the LED lamp corresponding to the on-site collection unit 10, so that the maintenance personnel may determine the ground fault location according to the location correspondence between the LED lamp and the high-voltage cable 50.
As shown in fig. 7, a plurality of fan box transformer units 40 may be disposed between the power generation end and the system end of the high voltage cable 50, the communication management module DPU of each fan box transformer unit 40 may be connected to the zero sequence current acquisition modules IO/ADC of the plurality of local acquisition units 10 near the fan box transformer unit 40 in a bus communication manner, the communication management modules DPUs of the plurality of fan box transformer units 40 may form an optical fiber ring network, and the data processing module DT of the monitoring alarm module 20 may be connected to the optical fiber ring network, so that each communication management module DPU may transmit the received zero sequence current to the data processing module DT through the optical fiber ring network.
The above description is only an alternative 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, which are made by using the contents of the present 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 high-voltage cable fault positioning device is characterized by comprising a monitoring alarm module, a fan box transformer substation unit, a switch cabinet unit and a plurality of local acquisition units arranged on a high-voltage cable;
the switch cabinet unit is connected with a high-voltage cable, the fan box transformer substation unit is connected with a plurality of on-site acquisition units, and the fan box transformer substation unit is also connected with the monitoring alarm module;
the switch cabinet unit is used for forming a zero-sequence current path when the high-voltage cable has a ground fault;
the local acquisition unit is used for acquiring zero sequence current when the high-voltage cable has a ground fault and sending the acquired zero sequence current to the fan box transformer substation unit;
the fan box transformer unit is used for supplying power to the on-site acquisition unit and sending the received zero sequence current to the monitoring alarm module;
and the monitoring alarm module is used for comparing the zero sequence currents acquired by the plurality of on-site acquisition units to determine the position of the ground fault of the high-voltage cable.
2. The high-voltage cable fault location device of claim 1, wherein the on-site collection unit comprises a zero sequence current transformer sleeved on the high-voltage cable;
the fan box transformer unit is used for receiving zero sequence currents detected by the plurality of zero sequence current transformers when the high-voltage cable has a ground fault and sending the received plurality of zero sequence currents to the monitoring alarm module;
the monitoring and alarming module is used for comparing zero sequence currents detected by every two adjacent zero sequence current transformers, and when detecting that the zero sequence currents detected by the two adjacent zero sequence current transformers are different, determining that the position of the ground fault of the high-voltage cable is between the two adjacent zero sequence current transformers.
3. The high-voltage cable fault locating device of claim 2, wherein the on-site acquisition unit comprises two zero-sequence current transformers and a zero-sequence current acquisition module, the high-voltage cable comprises a plurality of intermediate connectors, and the plurality of on-site acquisition units correspond to the plurality of intermediate connectors one to one;
two zero sequence current transformers are respectively sleeved at two ends of the middle joint, and the zero sequence current acquisition module is respectively connected with the two zero sequence current transformers;
the zero-sequence current acquisition module is used for calculating the difference value of the zero-sequence currents detected by the two zero-sequence current transformers and sending the zero-sequence currents detected by the two zero-sequence current transformers and the difference value calculation result to the monitoring alarm module through the fan box transformer unit;
and the monitoring alarm module is used for determining that the intermediate joint corresponding to the zero sequence current acquisition module has a ground fault when the difference calculation result sent by the zero sequence current acquisition module is not zero.
4. The high-voltage cable fault location device of claim 3, wherein the plurality of zero sequence current transformers are encoded in an order from the system end to the power generation end of the high-voltage cable, the switch cabinet unit is connected to the system end of the high-voltage cable, the switch cabinet unit includes a voltage transformer and a ground-to-ground complete equipment;
the grounding conversion complete equipment is used for forming a zero sequence current path when the high-voltage cable has a grounding fault;
the voltage transformer is used for detecting and obtaining zero sequence voltage when the high-voltage cable has a ground fault and sending the zero sequence voltage to the monitoring alarm module;
the monitoring and alarming module is used for comparing angles of all zero-sequence currents and the zero-sequence voltage according to a coding sequence when receiving the zero-sequence currents sent by the plurality of zero-sequence current transformers, and determining the position of the ground fault of the high-voltage cable between the zero-sequence current transformer with the largest coding in the leading zero-sequence voltage and the zero-sequence current transformer with the smallest coding in the lagging zero-sequence voltage when the angle of the zero-sequence currents is changed from the leading zero-sequence voltage to the lagging zero-sequence voltage.
5. The apparatus according to claim 4, wherein the monitoring and alarming module is further configured to perform an angular comparison between two zero sequence currents detected by two adjacent zero sequence current transformers, and determine a ground fault location of the high voltage cable between the two corresponding adjacent zero sequence current transformers when the two zero sequence currents are detected to have an angular difference of 180 °.
6. The high-voltage cable fault locating device of claim 4, wherein the switchgear unit further comprises a standard zero sequence current transformer;
the standard zero sequence current transformer is used for detecting and obtaining standard zero sequence current when the high-voltage cable has a ground fault;
the monitoring and alarming module is further configured to compare all zero-sequence currents with a standard zero-sequence current according to a coding sequence, divide all zero-sequence current transformers into a first transformer group with zero-sequence currents having the same magnitude as the standard zero-sequence currents and a second transformer group with zero-sequence currents having different magnitudes from the standard zero-sequence currents, and determine a position of a ground fault of the high-voltage cable between a zero-sequence current transformer with a largest coding in the first transformer group and a zero-sequence current transformer with a smallest coding in the second transformer group.
7. The high-voltage cable fault location device of claim 1, wherein the fan box transformer unit comprises a fan step-up transformer and a communication management module, the communication management module is connected with the plurality of zero sequence current acquisition modules, and the fan step-up transformer is connected with the communication module and the plurality of zero sequence current acquisition modules;
the fan step-up transformer is used for supplying power to the communication management module and the plurality of zero-sequence current acquisition modules;
and the communication management module is used for receiving the two zero-sequence currents and the difference value calculation result sent by the zero-sequence current acquisition module and sending the result to the monitoring alarm module.
8. The high-voltage cable fault location device according to claim 7, wherein the monitoring alarm module comprises a data processing module and an alarm module, and the data processing module is respectively connected with the fan box transformer unit and the alarm module;
the data processing module is used for receiving the zero sequence currents sent by all the zero sequence current acquisition modules and determining the ground fault position of the high-voltage cable according to the zero sequence current transformer which detects the abnormal zero sequence current;
the alarm module is used for sending an alarm signal when the data processing module determines the position of the ground fault of the high-voltage cable, wherein the alarm signal is an acoustic signal and/or an optical signal.
9. The high-voltage cable fault location device according to claim 8, wherein the number of the fan box transformer substation units is multiple, the communication management module of each fan box transformer substation unit is connected with the local acquisition units through a bus, the communication management modules of the fan box transformer substation units form an optical fiber ring network, and the data processing module is connected to the optical fiber ring network.
10. The high voltage cable fault locating device of claim 8, wherein the alarm module includes a plurality of LED lights corresponding to on-site acquisition units;
and the alarm module is also used for lighting the corresponding LED lamp corresponding to the local acquisition unit when the data processing module determines the ground fault position of the high-voltage cable.
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| CN202010684490.7A CN111638425A (en) | 2020-07-15 | 2020-07-15 | High-voltage cable fault positioning device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114034982A (en) * | 2021-11-16 | 2022-02-11 | 国网四川省电力公司检修公司 | Floating system direct current system ground fault point positioning method and system |
| CN115575857A (en) * | 2022-12-08 | 2023-01-06 | 江西广凯新能源股份有限公司 | Emergency protection method and device for high-voltage wire breakage |
-
2020
- 2020-07-15 CN CN202010684490.7A patent/CN111638425A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114034982A (en) * | 2021-11-16 | 2022-02-11 | 国网四川省电力公司检修公司 | Floating system direct current system ground fault point positioning method and system |
| CN115575857A (en) * | 2022-12-08 | 2023-01-06 | 江西广凯新能源股份有限公司 | Emergency protection method and device for high-voltage wire breakage |
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