CN111337852A - Distribution line fault detection method - Google Patents
Distribution line fault detection method Download PDFInfo
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- CN111337852A CN111337852A CN202010228581.XA CN202010228581A CN111337852A CN 111337852 A CN111337852 A CN 111337852A CN 202010228581 A CN202010228581 A CN 202010228581A CN 111337852 A CN111337852 A CN 111337852A
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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
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
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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
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Abstract
The embodiment of the invention provides a distribution line fault detection method, which comprises the following steps: disconnecting a fault line in the distribution lines from a system power supply; using a self-contained power supply to supply power to the fault line; and detecting the fault line by using a detector to find a fault point in the fault line. The embodiment of the invention provides a distribution line fault detection method, which can realize safe, reliable, accurate and quick detection of fault points. The distribution line fault detection method provided by the embodiment of the invention is a basis for ensuring reliable power supply, and a 10KV high-voltage line within a power supply range of dozens of miles does not exceed two hours, and a low voltage does not exceed half an hour.
Description
Technical Field
The invention relates to a power distribution line technology, in particular to a power distribution line fault detection method.
Background
Generally, the method for checking the permanent grounding and permanent short circuit fault of the high-voltage and low-voltage lines is as follows: high pressure: (1) line patrol, each electric pole of a fault line is checked once, and if no fault is found; (2) the branch line switch is opened, the main line is tried to be sent, if the trial sending is successful, the trial sending can be carried out only once, the branch line is specified to consume a large amount of manpower and material resources for the trial sending (3), and the fault point can not be detected in at least 12 hours. Low pressure: (1) line patrol, each electric pole of a fault line is checked once, and if no fault is found; (2) a plurality of persons are required to climb a pole to operate, each service wire is dismantled, and a specially-assigned person is contacted through a telephone to test power transmission; (3) consume a lot of manpower and material resources, and (4) cause frequent power failure of customer complaints.
In the existing design, the detection of distribution lines is time-consuming and laborious.
Disclosure of Invention
The embodiment of the invention provides a distribution line fault detection method, which can realize safe, reliable, accurate and quick detection of fault points. The distribution line fault detection method provided by the embodiment of the invention is a basis for ensuring reliable power supply, and a 10KV high-voltage line within a power supply range of dozens of miles does not exceed two hours, and a low voltage does not exceed half an hour.
The embodiment of the invention provides a distribution line fault detection method, which comprises the following steps:
disconnecting a fault line in the distribution lines from a system power supply;
using a self-contained power supply to supply power to the fault line;
and detecting the fault line by using a detector to find a fault point in the fault line.
Optionally, the distribution line is a low voltage line;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
taking out the low-voltage fuse;
removing the zero line at the outlet end of the protector;
after 4 conducting wires of the distribution line are electrically connected, the distribution line is electrically connected with the output end of the self-contained power supply; and grounding an input terminal of the self-contained power supply.
Optionally, the distribution line is a low voltage line;
before disconnecting a faulty line of the distribution lines from a system power supply, further comprising:
acquiring two leads causing short circuit;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
taking out the low-voltage fuse;
removing a zero line at the outlet end of the protector;
electrically connecting two leads without faults with one lead with a fault, and then electrically connecting the two leads with the output end of the self-contained power supply; and electrically connecting an input terminal of the self-contained power supply with the other wire having the fault.
Optionally, the distribution line is a high voltage line; before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
respectively short-connecting two ends of a connecting point formed by the distribution line and the transformer;
after connecting points formed by the distribution lines and the transformers are electrically connected with 3 leads between the transformers, the connecting points are electrically connected with the output end of the self-contained power supply; and grounding an input terminal of the self-contained power supply.
Optionally, the distribution line is a high voltage line;
before disconnecting a faulty line of the distribution lines from a system power supply, further comprising:
acquiring two leads causing short circuit;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
respectively short-circuiting and grounding a non-fault lead and a fault lead at two ends of a connecting point formed by a distribution line and a transformer;
and electrically connecting a connecting point formed by the distribution line and the transformer with one fault lead between the transformer and the output end of the self-contained power supply, and electrically connecting a connecting point formed by the distribution line and the transformer with the other fault lead between the transformer and the input end of the self-contained power supply.
Optionally, the distribution line is a power consumer line; before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
removing the outlet terminal of the fault line from the protector;
after 4 leads of the fault line are electrically connected, the fault line is electrically connected with the output end of the self-contained power supply; and grounding an input terminal of the self-contained power supply.
Optionally, the distribution line is a power consumer line;
before disconnecting a faulty line of the distribution lines from a system power supply, further comprising:
acquiring two leads causing short circuit;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
removing the outlet terminal of the fault line from the protector;
one faulty wire is electrically connected to the output of the self-contained power supply and the other faulty wire is electrically connected to the input of the self-contained power supply.
Optionally, the distribution line is a residential subscriber line;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
removing the outlet terminal of the fault line from the protector;
electrically connecting 2 leads of the fault line with the output end of the self-contained power supply; and grounding an input terminal of the self-contained power supply.
Optionally, the distribution line is a residential subscriber line;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
removing the outlet terminal of the fault line from the protector;
one faulty wire is electrically connected to the output of the self-contained power supply and the other faulty wire is electrically connected to the input of the self-contained power supply.
According to the distribution line fault detection method provided by the embodiment of the invention, after power failure, the self-contained power supply is used for supplying power to the fault line, and the fault line is detected by the detector, so that the fault point can be safely, reliably, accurately and quickly detected. The distribution line fault detection method provided by the embodiment of the invention is a basis for ensuring reliable power supply, and a 10KV high-voltage line within a power supply range of dozens of miles does not exceed two hours, and a low voltage does not exceed half an hour.
Drawings
Fig. 1 is a flowchart of a method for detecting a fault of a distribution line according to an embodiment of the present invention;
fig. 2 is a flowchart of another distribution line fault detection method according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a distribution line fault detection system according to an embodiment of the present invention;
FIG. 4 is a flow chart of another method for detecting a fault on a distribution line according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention;
FIG. 6 is a flow chart of another method for detecting a fault on a distribution line according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention;
FIG. 8 is a flow chart of another method for detecting a fault on a distribution line according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of another power distribution line fault detection system according to an embodiment of the present invention;
FIG. 10 is a flow chart of another method for detecting a fault on a distribution line according to an embodiment of the present invention;
FIG. 11 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention;
FIG. 12 is a flow chart of another method for detecting a fault on a distribution line according to an embodiment of the present invention;
FIG. 13 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention;
FIG. 14 is a flow chart of another method for detecting a fault on a distribution line according to an embodiment of the present invention;
FIG. 15 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention;
FIG. 16 is a flow chart of another method for detecting a fault on a distribution line according to an embodiment of the present invention;
FIG. 17 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention;
FIG. 18 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention;
fig. 19 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a flowchart of a distribution line fault detection method according to an embodiment of the present invention, and referring to fig. 1, the distribution line fault detection method includes the following steps:
and S101, disconnecting the fault line in the distribution line from a system power supply.
In this step, when detecting the distribution line, a power-off (or power-off) operation is first performed. The system power supply refers to an upper-level circuit of a faulty line.
Optionally, after step S101, the distribution line fault detection method may further include: and (4) testing electricity, namely testing whether the fault line is disconnected with a system power supply or not so as to improve the safety in the fault detection process.
And S102, transmitting power to the fault line by using a self-contained power supply.
In this step, the self-contained power supply may be a power supply that outputs an ac voltage of 36V or 1000HZ, for example. The reason why the 1000HZ self-contained power supply is used instead of the 50HZ power supply is that in order that the current output by the self-contained power supply does not pass through the transformer winding when the short-circuit fault of the high-voltage line is detected, dozens of or hundreds of transformers are connected to each high-voltage line (the inductance of the inductor is in proportion to the frequency), but only one high-voltage capacitor is needed, and when the short-circuit fault of the high-voltage line is detected, the high-voltage capacitor is only needed to be turned off.
And S103, detecting the fault line by using a detector to search a fault point in the fault line.
In this step, the detector may include electric field induction elements such as coils and/or capacitors, and the detector may detect a fault point in a fault line without contact.
Optionally, after step S103, that is, after finding the fault point in the faulty line, the fault is cleared and the power is supplied normally.
According to the distribution line fault detection method provided by the embodiment of the invention, after power failure, the self-contained power supply is used for supplying power to the fault line, and the fault line is detected by the detector, so that the fault point can be safely, reliably, accurately and quickly detected.
Fig. 2 is a flowchart of another distribution line fault detection method according to an embodiment of the present invention, and fig. 3 is a schematic diagram of a distribution line fault detection system according to an embodiment of the present invention, where the distribution line is a low-voltage line, and the low-voltage distribution line is a line between a transformer and a user. Referring to fig. 2 and 3, the distribution line fault detection method includes the steps of:
and S201, disconnecting the fault line in the distribution line from the system power supply.
In this step, the system power source may be a line after the transformer and before the user's security device.
And S202, taking out the low-voltage fuse.
In the step, the low-voltage fuse is taken out, so that the protector and the outlet terminal have obvious disconnection points, and the safety of line detection is further improved. The protector in this step is a protector in a low-voltage line, and the outlet terminal is a terminal of a lead led out from the output end of the protector.
S203, removing the zero line at the outlet end of the protector.
In this step, the zero line at the outlet end of the protector (not shown in fig. 2 and 3) is removed, so that the fault line to be detected is completely separated from the transformer (not shown in fig. 2 and 3), and the safety of line detection is further improved.
S204, after the 4 leads of the distribution line are electrically connected, the 4 leads are electrically connected with the output end of the self-contained power supply 10; and the input terminal of the self-contained power supply 10 is grounded.
In this step, the outgoing line terminals (the a-phase wire, the B-phase wire, the C-phase wire, and the zero line N) are connected, the a-phase wire, the B-phase wire, the C-phase wire, and the zero line N are electrically connected to the output end of the self-contained power supply 10, and the input end of the self-contained power supply 10 is grounded.
S205, the self-contained power supply 10 is used to supply power to the faulty line.
In this step, the self-contained power supply 10 is used to supply power to the a-phase conductor, the B-phase conductor, the C-phase conductor, and the zero line N, and as shown in fig. 3, if the B-phase conductor has a permanent ground fault, the output terminal of the self-contained power supply 10, the B-phase conductor, the ground, and the input terminal of the self-contained power supply 10 form a complete loop.
And S206, detecting the fault line by using a detector to search a fault point in the fault line.
The distribution line fault detection method provided by the embodiment of the invention is suitable for permanent ground fault detection of a low-voltage line.
Fig. 4 is a flowchart of another distribution line fault detection method according to an embodiment of the present invention, and fig. 5 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention, and referring to fig. 4 and fig. 5, the distribution line fault detection method includes the following steps:
s301, two leads causing short circuit are obtained.
In this step, two wires causing a short circuit are acquired, that is, it is determined which two wires are short-circuited.
And S302, disconnecting the fault line in the distribution line from the system power supply.
And S303, taking out the low-voltage fuse.
S304, removing the zero line at the outlet end of the protector.
S305, after two leads without faults are electrically connected with one lead with faults, the two leads are electrically connected with the output end of the self-contained power supply; and electrically connecting the input terminal of the self-contained power supply with the faulty other wire.
In this step, the C-phase conductor and the neutral wire N are short-circuited, for example. And the phase A lead, the phase B lead and the zero line N are electrically connected with the output end of the self-contained power supply 10, and the phase C lead is electrically connected with the input end of the self-contained power supply 10. The output end of the self-contained power supply 10, the zero line N, C phase conductor and the input end of the self-contained power supply 10 form a completion loop.
S306, the self-contained power supply 10 is used to supply power to the faulty line.
In this step, the self-contained power supply 10 is used to supply power to the a-phase wire, the B-phase wire, and the zero line N, and as shown in fig. 5, if the C-phase wire and the zero line N are short-circuited, the output end of the self-contained power supply 10, the B-phase wire, the ground, and the input end of the self-contained power supply 10 form a complete loop.
And S307, detecting the fault line by using the detector to search a fault point in the fault line.
The distribution line fault detection method provided by the embodiment of the invention is suitable for permanent short circuit fault detection of a low-voltage line.
Fig. 6 is a flowchart of another distribution line fault detection method according to an embodiment of the present invention, and fig. 7 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention, where the distribution line is a high-voltage line, for example, a 10KV high-voltage line, and referring to fig. 6 and fig. 7, the distribution line fault detection method includes the following steps:
and S401, disconnecting the fault line in the distribution line from the system power supply.
In this step, the system power source may be the line after the power supply station and before the transformer 30.
Alternatively, after step S401, a power distribution area with a relatively moderate faulty line may be selected for the fault point detection operation, for example, 100 power distribution areas are included in the whole high-voltage line, and the 49 th or 50 th power distribution area located in the middle may be selected for the fault point detection operation. The distribution substation is provided with a transformer 30.
And S402, respectively short-circuiting two ends of a connection point formed by the distribution line and the transformer 30.
In this step, illustratively, two sets of connection lines are connected to the electric poles on both sides of the transformer 30, and each set of connection lines is connected to all the wires in the distribution line, that is, each set of connection lines short-circuits the a-phase wire, the B-phase wire, and the C-phase wire.
Illustratively, when detecting a permanent ground fault, the high-voltage line needs to short together the phase a conductor, the phase B conductor and the phase C conductor but cannot be grounded, so that the fault line is prevented from being powered by mistake, and safety is ensured (for example, a 10KV high-voltage line short-circuit fault is automatically tripped, and a ground fault is manually operated). The reason why the grounding cannot be carried out is that when a fault grounding point is detected, a self-contained power supply is used for transmitting power to a fault line, a circuit is formed by passing through the grounding fault point and the ground, the circuit becomes a closed circuit, and the grounding cannot be carried out repeatedly.
S403, after the connecting point formed by the distribution line and the transformer 30 is electrically connected with 3 conducting wires between the transformer 30, the connecting point is electrically connected with the output end of the self-contained power supply 10; and the input terminal of the self-contained power supply 10 is grounded.
S404, the self-contained power supply 10 is used to supply power to the faulty line.
And S405, detecting the fault line by using a detector to search a fault point in the fault line.
Optionally, a drop-out fuse 20 may be further included in the distribution line fault detection system, and the drop-out fuse 20 is disposed on the line before the transformer 30. The distribution line between the drop-out fuse 20 and the transformer 30 may be electrically connected to the output terminal of the self-contained power supply 10.
The distribution line fault detection method provided by the embodiment of the invention is suitable for permanent ground fault detection of a high-voltage line.
Fig. 8 is a flowchart of another distribution line fault detection method according to an embodiment of the present invention, and fig. 9 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention, where the distribution line is a high-voltage line, for example, a 10KV high-voltage line, and referring to fig. 8 and fig. 9, the distribution line fault detection method includes the following steps:
s501, two leads causing short circuit are obtained.
And S502, disconnecting the fault line in the distribution line from the system power supply.
Optionally, after step S502, the method may further include: and the high-voltage capacitor on the fault line is pulled open, namely, the high-voltage capacitor on the fault line is powered off, so that the detection safety is further improved.
And S503, respectively short-circuiting and grounding the non-fault lead and the fault lead at two ends of a connecting point formed by the distribution line and the transformer.
In this step, for example, if the a-phase wire and the B-phase wire are short-circuited, the B-phase wire and the C-phase wire at two ends of the connection point are respectively short-circuited and grounded. That is, two sets of connection lines are used, each set of connection lines shorting and grounding the B-phase and C-phase wires.
Illustratively, when a permanent short circuit fault occurs in a high-voltage line, a phase which does not have a fault is short-circuited with any phase which has a fault (for example, a phase a conductor and a phase B conductor are short-circuited, a phase B conductor and a phase C conductor are short-circuited when a ground wire is hooked, the self-contained power supply 10 supplies power to the phase a conductor and the phase B conductor only, and a closed loop is formed by the phase a short-circuit point and the phase B short-circuit point), so that the high-voltage capacitor must be turned off.
S504, a connection point formed by the distribution line and the transformer and one fault lead between the transformer are electrically connected with the output end of the self-contained power supply, and the connection point formed by the distribution line and the transformer and the other fault lead between the transformer are electrically connected with the input end of the self-contained power supply.
And S505, transmitting power to the fault line by using a self-contained power supply.
S506, the self-contained power supply 10 is used to supply power to the faulty line.
And S507, detecting the fault line by using a detector to search a fault point in the fault line.
The distribution line fault detection method provided by the embodiment of the invention is suitable for permanent short-circuit fault detection of a high-voltage line.
Fig. 10 is a flowchart of another distribution line fault detection method according to an embodiment of the present invention, fig. 11 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention, the distribution line is a power consumer line, and referring to fig. 10 and fig. 11, the distribution line fault detection method includes the following steps:
and S601, disconnecting the fault line in the distribution line from the system power supply.
S602, the outlet terminal of the fault line is removed from the protector 40.
Illustratively, before step S602, the phase a wire, the phase B wire, the phase C wire, and the neutral wire N may be marked correspondingly.
S603, electrically connecting 4 leads of the fault line and then electrically connecting the leads with the output end of the self-contained power supply; and grounding the input terminal of the self-contained power supply.
S604, the self-contained power supply 10 is used to supply power to the faulty line.
And S605, detecting the fault line by using a detector to search a fault point in the fault line.
The distribution line fault detection method provided by the embodiment of the invention is suitable for permanent ground fault detection of power users.
Fig. 12 is a flowchart of another distribution line fault detection method according to an embodiment of the present invention, and fig. 13 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention, where the distribution line is a power consumer line, and referring to fig. 12 and fig. 13, the distribution line fault detection method includes the following steps:
and S701, acquiring two leads causing short circuit.
And S702, disconnecting the fault line in the distribution line from the system power supply.
And S703, removing the outlet terminal of the fault line from the protector 40.
Illustratively, before step S703, the a-phase wire, the B-phase wire, the C-phase wire, and the zero line N may be correspondingly marked.
S704, electrically connecting one faulty wire with the output terminal of the self-contained power supply 10, and electrically connecting the other faulty wire with the input terminal of the self-contained power supply 10.
In this step, the phase a conductor and the neutral wire N are short-circuited, for example. The zero line N is electrically connected with the output end of the self-contained power supply 10, and the A-phase lead is electrically connected with the input end of the self-contained power supply 10.
S705, the self-contained power supply 10 is used to supply power to the faulty line.
And S706, detecting the fault line by using a detector to search a fault point in the fault line.
The distribution line fault detection method provided by the embodiment of the invention is suitable for permanent short circuit fault detection of a power user.
Fig. 14 is a flowchart of another distribution line fault detection method according to an embodiment of the present invention, and fig. 15 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention, where the distribution line is a residential subscriber line, and referring to fig. 14 and fig. 15, the distribution line fault detection method includes the following steps:
and S801, disconnecting the fault line in the distribution line from the system power supply.
And S802, removing the outlet terminal of the fault line from the protector 40.
S803, electrically connecting 2 leads of the fault line and then electrically connecting the leads with the output end of the self-contained power supply; and grounding the input terminal of the self-contained power supply.
In this step, the zero line N is electrically connected to the output terminal of the self-contained power supply after being short-circuited with the phase line (specifically, the live line L).
S804, the self-contained power supply 10 is used to supply power to the faulty line.
And S805, detecting the fault line by using a detector to search a fault point in the fault line.
The distribution line fault detection method provided by the embodiment of the invention is suitable for permanent ground fault detection of residential users.
Fig. 16 is a flowchart of another distribution line fault detection method according to an embodiment of the present invention, and fig. 17 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention, where the distribution line is a residential subscriber line, and referring to fig. 16 and 17, the distribution line fault detection method includes the following steps:
and S901, disconnecting a fault line in the distribution line from a system power supply.
S902, the outlet terminal of the fault line is removed from the protector 40.
S903, electrically connecting one faulty wire to the output terminal of the self-contained power supply 10, and electrically connecting the other faulty wire to the input terminal of the self-contained power supply 10.
In this step, the zero line N is electrically connected to the output terminal of the self-contained power supply 10, and the phase line (specifically, the live line L) is electrically connected to the input terminal of the self-contained power supply 10.
S904, the self-contained power supply 10 is used to supply power to the faulty line.
And S905, detecting the fault line by using a detector to search a fault point in the fault line.
The distribution line fault detection method provided by the embodiment of the invention is suitable for permanent short circuit fault detection of residential users.
Fig. 18 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention, and referring to fig. 18, when the distribution line is an underground cable 70, the distribution line fault detection method includes the following steps:
1. and (5) power failure.
2. And (6) testing electricity.
3. And marking the A-phase lead, the B-phase lead, the C-phase lead and the zero line N correspondingly from left to right.
4. All four wires of the lower stub of the user protector 40 are removed so that all wires leave the protector 40.
5. And short-circuit outlet terminals.
In this step, in some possible embodiments, if the underground cable 70 is a low-voltage cable, the low-voltage cable connects the a-phase conductor, the B-phase conductor, the C-phase conductor, and the neutral N-conductor. In other possible embodiments, if the underground cable 70 is a high voltage cable, the high voltage cables are connected (phase a conductor, phase B conductor, phase C conductor).
6. And (5) supplying power to the fault line.
Illustratively, permanent ground faults of the underground cable 70 are detected, as the case may be. Typically, four conductors are connected together and a 220 volt ac current is connected in series to the fault line through a 1KW electrical load 60. A switch 50 may also be connected in series with the line of the consumer 60.
In other embodiments, the phase a wire, the phase B wire, the phase C wire, and the neutral wire N shown in fig. 18 may be electrically connected to the output terminal of the self-contained power supply, and the input terminal of the self-contained power supply may be grounded.
7. And detecting the fault line by using the detector to find a fault point in the fault line.
The distribution line fault detection method provided by the embodiment of the invention is suitable for permanent ground fault detection of underground cables.
Fig. 19 is a schematic diagram of another distribution line fault detection system according to an embodiment of the present invention, and referring to fig. 19, when the distribution line is an underground cable 70, the distribution line fault detection method includes the following steps:
1. and (5) power failure.
2. And (6) testing electricity.
3. And marking the A-phase lead, the B-phase lead, the C-phase lead and the zero line N correspondingly from left to right.
4. All four wires of the lower stub of the user protector 40 are removed so that all wires leave the protector 40.
5. And determining the short-circuit fault lead.
Illustratively, the a-phase and C-phase wires are shorted.
6. And (5) supplying power to the fault line.
Illustratively, 220V electrical loads 60 with a power of 22KW are connected in series to the fault line. A switch 50 may also be connected in series with the line of the consumer 60. In other embodiments, the phase B wire and the neutral wire N shown in fig. 19 may be electrically connected to the output terminal and the input terminal of the self-contained power supply, respectively. The power of the electrical appliance 60 is determined according to the depth of the buried line, and the power is high when the depth is large and low when the depth is small.
7. And detecting the fault line by using the detector to find a fault point in the fault line.
The distribution line fault detection method provided by the embodiment of the invention is suitable for detecting the permanent short circuit fault of the underground cable.
In addition, the embodiment of the invention also discloses the application of the distribution line fault detection method and a certain application scenario (including but not limited to the application scenario):
the application is as follows: measuring the permanent grounding of the high-voltage and low-voltage lines; a permanent short circuit fault; the leakage current of the station area outgoing line total protector is checked, wherein the zero sequence current is more than or equal to 40 CmmA; the underground cable meeting the conditions is permanently grounded and is permanently short-circuited; indoor open lines, hidden lines, underground, above a ceiling and the like which meet the conditions.
In order to provide electrical safety, a safety cut-out and a fuse must be installed. The protector has the function that when a line or equipment is aged or electric leakage is generated due to other reasons, the protector acts (trips) to cut off a power supply, so that personal safety is guaranteed; the fuse has the functions that when a short circuit or overload occurs to a line or equipment, the fuse is fused, the air switch trips, and the power supply is cut off. It is necessary to install a total protector, a medium and domestic protector and a short circuit protection.
The rated operating current of the protector is selectable. At present, the protector on the market has wide selectable range, the lowest gears of rated action current are 50mA, 100mA, 150mA and 300mA, and the highest gears are 800mA, 1000mA and 1500mA, and can be bought. The contradiction is that when the grounding current is larger than or equal to the rated action current, the protector acts, trips and cuts off power, so the smaller the rated action current is, the safer the safety is; however, the smaller the rated operating current is set, the more unreliable the power supply is. When the leakage current of the total protector in the transformer area is more than or equal to 40mA and less than 50mA, the total protector can normally operate, and if the leakage current of more than ten mA is added in rainy days or other reasons, the total protector can immediately act to trip, so that frequent tripping and power failure are caused. Frequent tripping and power failure are one of the most annoying phenomena for customers and are also one of the most easily causing customer complaints.
The product can perfectly solve the contradiction. The rated action current of the transformer area total protector is set to be 50mA, and the product can capture the leakage current of which the leakage current is more than 15mA at a certain point, so that the fault can be accurately, quickly, safely and reliably checked. If the leakage current is larger than 5A, the approximate position of the leakage fault can be determined immediately through measurement, and then the fault point is locked, so that the fault is eliminated as soon as possible, the power supply is recovered, the safe and reliable operation of a line is ensured, and meanwhile, the electricity utilization safety of residents is guaranteed to the greatest extent, and the load switch is time-saving, labor-saving and indispensable.
In addition, the embodiment of the invention also discloses the notice items of the distribution line fault detection method:
forbidding mistakenly touching the electrified high-voltage wire in the detection process! When a fault of a low-voltage line is detected on a line erected on the same high-voltage and low-voltage poles or a multi-loop low-voltage line erected on the same low-voltage poles, current induction of the high-voltage line and the low-voltage line is prevented from causing a detection device to give out false alarm sound; when a permanent earth fault is detected, if the electric quantity of the self-contained power supply is insufficient or other reasons, the power can not be supplied to a fault line, any phase of a transformer can be adopted in a low-voltage line, the fault line is supplied with power after the power passes through a protector and is connected in series through a 15W bulb or an energy-saving lamp, one 12V direct-current power supply is adopted in a high-voltage line, an inverter is connected to output 220V alternating current, and the power is supplied to the fault line after the power passes through the 15W bulb or the energy-saving lamp and is connected in; (if the faulty line is below the high and low voltage lines, it is detected on each branch line of the faulty line trunk); when a fault is detected, the detection device is covered with a plastic bag when raining, so that the detection device is prevented from water inflow.
When a fault line is detected, the line alarms to indicate that the fault is behind the line, and does not alarm to indicate that the fault is not behind the line, and if the fault is not alarmed, the fault does not exist.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (9)
1. A distribution line fault detection method is characterized by comprising the following steps:
disconnecting a fault line in the distribution lines from a system power supply;
using a self-contained power supply to supply power to the fault line;
and detecting the fault line by using a detector to find a fault point in the fault line.
2. The method of claim 1, wherein the distribution line is a low voltage line;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
taking out the low-voltage fuse;
removing the zero line at the outlet end of the protector;
after 4 conducting wires of the distribution line are electrically connected, the distribution line is electrically connected with the output end of the self-contained power supply; and grounding an input terminal of the self-contained power supply.
3. The method of claim 1, wherein the distribution line is a low voltage line;
before disconnecting a faulty line of the distribution lines from a system power supply, further comprising:
acquiring two leads causing short circuit;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
taking out the low-voltage fuse;
removing a zero line at the outlet end of the protector;
electrically connecting two leads without faults with one lead with a fault, and then electrically connecting the two leads with the output end of the self-contained power supply; and electrically connecting an input terminal of the self-contained power supply with the other wire having the fault.
4. The method of claim 1, wherein the distribution line is a high voltage line; before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
respectively short-connecting two ends of a connecting point formed by the distribution line and the transformer;
after connecting points formed by the distribution lines and the transformers are electrically connected with 3 leads between the transformers, the connecting points are electrically connected with the output end of the self-contained power supply; and grounding an input terminal of the self-contained power supply.
5. The method of claim 1, wherein the distribution line is a high voltage line;
before disconnecting a faulty line of the distribution lines from a system power supply, further comprising:
acquiring two leads causing short circuit;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
respectively short-circuiting and grounding a non-fault lead and a fault lead at two ends of a connecting point formed by a distribution line and a transformer;
and electrically connecting a connecting point formed by the distribution line and the transformer with one fault lead between the transformer and the output end of the self-contained power supply, and electrically connecting a connecting point formed by the distribution line and the transformer with the other fault lead between the transformer and the input end of the self-contained power supply.
6. The method of claim 1, wherein the distribution line is a power consumer line; before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
removing the outlet terminal of the fault line from the protector;
after 4 leads of the fault line are electrically connected, the fault line is electrically connected with the output end of the self-contained power supply; and grounding an input terminal of the self-contained power supply.
7. The method of claim 1, wherein the distribution line is a power consumer line;
before disconnecting a faulty line of the distribution lines from a system power supply, further comprising:
acquiring two leads causing short circuit;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
removing the outlet terminal of the fault line from the protector;
one faulty wire is electrically connected to the output of the self-contained power supply and the other faulty wire is electrically connected to the input of the self-contained power supply.
8. The method of claim 1, wherein the distribution line is a residential customer line;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
removing the outlet terminal of the fault line from the protector;
electrically connecting 2 leads of the fault line with the output end of the self-contained power supply; and grounding an input terminal of the self-contained power supply.
9. The method of claim 1, wherein the distribution line is a residential customer line;
before the fault line is powered by using a self-contained power supply, the method further comprises the following steps:
removing the outlet terminal of the fault line from the protector;
one faulty wire is electrically connected to the output of the self-contained power supply and the other faulty wire is electrically connected to the input of the self-contained power supply.
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| CN202010228581.XA CN111337852A (en) | 2020-03-27 | 2020-03-27 | Distribution line fault detection method |
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| CN202010228581.XA CN111337852A (en) | 2020-03-27 | 2020-03-27 | Distribution line fault detection method |
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Application publication date: 20200626 |