CN115856496A - Distribution line fault detection and identification method based on two-end information acquisition - Google Patents
Distribution line fault detection and identification method based on two-end information acquisition Download PDFInfo
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- CN115856496A CN115856496A CN202211441649.8A CN202211441649A CN115856496A CN 115856496 A CN115856496 A CN 115856496A CN 202211441649 A CN202211441649 A CN 202211441649A CN 115856496 A CN115856496 A CN 115856496A
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Abstract
The invention provides a distribution line fault detection and identification method based on two-end information acquisition, which comprises the following steps of: (1): collecting current and voltage signals at two ends of the distribution line; (2): calculating the normal loss of the distribution line according to the current signal at the head end of the distribution line; (3): judging whether the current and voltage signals of the load end of the distribution line are abnormal or not, and if so, alarming; if not, entering (4); (4): calculating the actual loss of the distribution line according to the current and voltage signals at the two ends of the distribution line; (5): judging whether the loss of the distribution line is normal or not, if so, returning to the step (1); if not, entering (6); (6): and determining the fault type of the distribution line. The invention provides a distribution line fault detection and identification method based on two-end information acquisition, which can accurately and conveniently determine whether a fault and a fault type exist in a distribution line.
Description
Technical Field
The invention belongs to the technical field of electric power detection, and particularly relates to a distribution line fault detection and identification method based on two-end information acquisition.
Background
The distribution line is an important component of an electric power system, and the safety and the reliability of the distribution line are important guarantees for ensuring a power grid and users.
The invention provides a distribution line fault detection and identification method based on two-end information acquisition, which is used for acquiring working information of two ends of a distribution line, calculating the actual loss of the distribution line under the condition of ensuring the accuracy of load end information, further judging whether the distribution line has a fault or not, judging the specific fault type according to the amplitude of a phase voltage signal of the head end of the distribution line, preventing the judgment error caused by inaccurate signal acquisition and simultaneously helping a worker to timely process the fault.
Disclosure of Invention
The invention provides a distribution line fault detection and identification method based on two-end information acquisition, which can accurately and conveniently determine whether a fault and a fault type exist in a distribution line.
The invention specifically relates to a distribution line fault detection and identification method based on two-end information acquisition, which comprises the following steps:
step (1): collecting current and voltage signals at two ends of the distribution line;
step (2): calculating the normal loss of the distribution line according to the current signal of the head end of the distribution line;
and (3): judging whether the current and voltage signals of the load end of the distribution line are abnormal or not, and if so, alarming; if not, entering the step (4);
and (4): calculating the actual loss of the distribution line according to the current and voltage signals at the two ends of the distribution line;
and (5): judging whether the loss of the distribution line is normal or not, if so, returning to the step (1); if not, entering the step (6);
and (6): and determining the fault type of the distribution line.
The current and voltage signals of the power end of the circuit are collected by a first current sensor and a first voltage sensor; and current and voltage signals of the line load end are acquired by adopting a second current sensor and a second voltage sensor.
The method for calculating the normal loss of the line comprises the following steps:wherein I 1 R is the line impedance for the line head end current signal.
The method for judging whether the current and voltage signals of the load end of the distribution line are abnormal or not comprises the following steps:
firstly, collecting a secondary loop voltage signal of the second current sensor and collecting a secondary loop current signal of the second voltage sensor;
secondly, calculating the impedance of a secondary loop of the second current sensor and the impedance of a secondary loop of the second voltage sensor;
and thirdly, judging whether the secondary loop impedance of the second current sensor and the secondary loop impedance of the second voltage-current sensor are abnormal or not, and if so, judging whether the current and voltage signals of the load end of the distribution line are abnormal or not.
The algorithm for calculating the secondary loop impedance of the second current sensor is Z LA =U NA /I 2 ,U NA Is the secondary loop voltage signal of the second current sensor, I 2 And the current signal is the current signal of the load end of the distribution circuit.
The algorithm for calculating the impedance of the secondary loop of the second voltage sensor is Z LV =U 2 /I NV ,U 2 For the load terminal voltage signal of said distribution line, I NV Is the second voltage sensor secondary loop current signal.
The method for judging whether the secondary loop impedance of the second current sensor and the secondary loop impedance of the second voltage sensor are abnormal comprises the following steps:
firstly, acquiring a working temperature signal of the second current sensor and a working temperature signal of the second voltage sensor;
secondly, extracting a secondary loop impedance reference value of a second current sensor and a secondary loop impedance reference value of a second voltage sensor according to the temperature signal;
finally, judging whether the secondary loop impedance of the second current sensor is larger than the secondary loop impedance reference value of the second current sensor, if so, judging that the current at the load end of the distribution circuit is abnormal; if not, judging whether the secondary loop impedance of the second voltage sensor is larger than the secondary loop impedance reference value of the second voltage sensor, if so, judging that the load end voltage of the distribution line is abnormal.
The algorithm for calculating the actual loss of the line according to the current and voltage signals at the two ends of the line is as follows: p = U 1 I 1 -U 2 I 2 Wherein U is 1 Is the line head end voltage signal.
The method for judging whether the loss of the distribution line is normal or not comprises the following steps:
firstly, calculating the difference value of the actual loss and the normal loss;
secondly, judging whether the difference value is larger than a line loss reference value, if so, judging that the loss of the distribution line is abnormal; if not, the loss of the distribution line is normal.
The specific method for determining the fault type of the distribution line comprises the following steps:
firstly, extracting the amplitude of a phase voltage signal at the head end of the distribution line;
secondly, constructing an envelope curve according to the amplitude of the phase voltage signal at the head end of the distribution line;
thirdly, calculating the slope value of each point on the envelope curve between two adjacent positive amplitude points in real time;
thirdly, calculating the average value of the slope values;
finally, judging whether the slope value average value is larger than a slope reference value or not, if so, generating instantaneous ground fault on the distribution line; if not, a permanent ground fault occurs on the distribution line.
Compared with the prior art, the beneficial effects are: the distribution line fault detection and identification method collects working information of two ends of a distribution line, calculates actual loss of the distribution line under the condition of ensuring accurate load end information, further judges whether the distribution line has faults or not, and judges specific fault types according to the amplitude of a phase voltage signal of the head end of the distribution line, so that convenience and accuracy of detection are improved.
Drawings
Fig. 1 is a work flow chart of a distribution line fault detection and identification method based on two-end information acquisition according to the present invention.
Detailed Description
The following describes in detail a specific embodiment of the distribution line fault detection and identification method based on two-end information acquisition according to the present invention with reference to the accompanying drawings.
As shown in fig. 1, the method for detecting and identifying a fault of a distribution line of the present invention includes the following steps:
step (1): collecting current and voltage signals at two ends of the distribution line;
step (2): and calculating the normal loss of the distribution line according to the head end current signal of the distribution line:wherein I 1 Is the line head end current signal, R is the line impedance;
and (3): judging whether the current and voltage signals of the load end of the distribution line are abnormal or not, and if so, alarming; if not, entering the step (4);
and (4): calculating the actual loss of the distribution line according to the current and voltage signals at the two ends of the distribution line: p = U 1 I 1 -U 2 I 2 Wherein U is 1 For said line head end voltage signal, U 2 For the load terminal voltage signal of said distribution line, I 2 The current signal is the load end current signal of the distribution circuit;
and (5): if the difference value is larger than the line loss reference value, if so, the loss of the distribution line is abnormal, and the step (6) is carried out; if not, the loss of the distribution line is normal, and the step (1) is returned.
And (6): determining the fault type of the distribution line:
firstly, extracting the amplitude of a phase voltage signal at the head end of the distribution line;
secondly, constructing an envelope curve according to the amplitude of the phase voltage signal at the head end of the distribution line;
thirdly, calculating the slope value of each point on the envelope curve between two adjacent positive amplitude points in real time;
thirdly, calculating the average value of the slope values;
finally, judging whether the average value of the slope values is larger than a slope reference value or not, if so, judging that the distribution line has an instantaneous ground fault; if not, a permanent ground fault occurs on the distribution line.
The current and voltage signals of the power end of the circuit are collected by a first current sensor and a first voltage sensor; and current and voltage signals of the line load end are acquired by adopting a second current sensor and a second voltage sensor.
The method for judging whether the current and voltage signals of the load end of the distribution line are abnormal or not comprises the following steps:
firstly, collecting a secondary loop voltage signal of the second current sensor and collecting a secondary loop current signal of the second voltage sensor;
secondly, calculating the secondary loop impedance Z of the second current sensor LA =U NA /I 2 ,U NA Is the secondary loop voltage signal of the second current sensor, I 2 The current signal is the load end current signal of the distribution circuit; the second voltage sensor secondary loop impedance Z LV =U 2 /I NV ,U 2 For the load terminal voltage signal of said distribution line, I NV A secondary loop current signal for the second voltage sensor;
and thirdly, judging whether the secondary loop impedance of the second current sensor and the secondary loop impedance of the second voltage-current sensor are abnormal or not, and if so, judging whether the current and voltage signals of the load end of the distribution line are abnormal or not.
The method for judging whether the secondary loop impedance of the second current sensor and the secondary loop impedance of the second voltage sensor are abnormal comprises the following steps:
firstly, acquiring a working temperature signal of the second current sensor and a working temperature signal of the second voltage sensor;
secondly, extracting a secondary loop impedance reference value of a second current sensor and a secondary loop impedance reference value of a second voltage sensor according to the temperature signal;
finally, judging whether the secondary loop impedance of the second current sensor is larger than the secondary loop impedance reference value of the second current sensor, if so, judging that the current at the load end of the distribution circuit is abnormal; if not, judging whether the impedance of the secondary loop of the second voltage sensor is larger than the reference value of the impedance of the secondary loop of the second voltage sensor, and if so, judging that the voltage of the load end of the distribution line is abnormal.
And the line loss reference value is selected according to the working temperature of the distribution line.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A distribution line fault detection and identification method based on information acquisition at two ends is characterized by comprising the following steps:
step (1): collecting current and voltage signals at two ends of the distribution line;
step (2): calculating the normal loss of the distribution line according to the current signal at the head end of the distribution line;
and (3): judging whether the current and voltage signals of the load end of the distribution line are abnormal or not, and if so, alarming; if not, entering the step (4);
and (4): calculating the actual loss of the distribution line according to the current and voltage signals at the two ends of the distribution line;
and (5): judging whether the loss of the distribution line is normal or not, if so, returning to the step (1); if not, entering the step (6);
and (6): and determining the fault type of the distribution line.
2. The distribution line fault detection and identification method based on two-end information acquisition is characterized in that current and voltage signals of a power supply end of the line are acquired by a first current sensor and a first voltage sensor; and current and voltage signals of the line load end are acquired by adopting a second current sensor and a second voltage sensor.
3. The distribution line fault detection and identification method based on two-end information acquisition as claimed in claim 2, wherein the calculation method of the normal loss of the line is as follows: p R =I 1 2 R, wherein I 1 R is the line impedance for the line head end current signal.
4. The method for detecting and identifying the fault of the distribution line based on the two-end information acquisition of claim 3 is characterized in that the method for judging whether the current and voltage signals of the load end of the distribution line are abnormal is as follows:
firstly, collecting a secondary loop voltage signal of the second current sensor and collecting a secondary loop current signal of the second voltage sensor;
secondly, calculating the impedance of a secondary loop of the second current sensor and the impedance of a secondary loop of the second voltage sensor;
and thirdly, judging whether the secondary loop impedance of the second current sensor and the secondary loop impedance of the second voltage-current sensor are abnormal or not, and if so, judging whether the current and voltage signals of the load end of the distribution line are abnormal or not.
5. The distribution line fault detection and identification method based on two-terminal information acquisition as claimed in claim 4, wherein the second current sensor secondary calculation is performedThe algorithm of the loop impedance is Z LA =U NA /I 2 ,U NA Is the secondary loop voltage signal of the second current sensor, I 2 And the current signal is the current signal at the load end of the distribution circuit.
6. The distribution line fault detection and identification method based on two-terminal information acquisition as claimed in claim 5, characterized in that the algorithm for calculating the secondary loop impedance of the second voltage sensor is Z LV =U 2 /I NV ,U 2 For the load terminal voltage signal of said distribution line, I NV Is the second voltage sensor secondary loop current signal.
7. The distribution line fault detection and identification method based on two-end information acquisition of claim 6, wherein the method for judging whether the secondary loop impedance of the second current sensor and the secondary loop impedance of the second voltage sensor are abnormal is as follows:
firstly, acquiring a working temperature signal of the second current sensor and a working temperature signal of the second voltage sensor;
secondly, extracting a secondary loop impedance reference value of a second current sensor and a secondary loop impedance reference value of a second voltage sensor according to the temperature signal;
finally, judging whether the secondary loop impedance of the second current sensor is larger than the secondary loop impedance reference value of the second current sensor, if so, judging that the current at the load end of the distribution circuit is abnormal; if not, judging whether the secondary loop impedance of the second voltage sensor is larger than the secondary loop impedance reference value of the second voltage sensor, if so, judging that the load end voltage of the distribution line is abnormal.
8. The distribution line fault detection and identification method based on two-end information acquisition according to claim 7, wherein the algorithm for calculating the actual loss of the line according to the current and voltage signals at the two ends of the line is as follows: p = U 1 I 1 -U 2 I 2 Wherein U is 1 Is the line head end voltage signal.
9. The distribution line fault detection and identification method based on two-end information acquisition according to claim 8, wherein the method for judging whether the loss of the distribution line is normal is as follows:
firstly, calculating the difference value of the actual loss and the normal loss;
secondly, judging whether the difference value is larger than a line loss reference value, if so, judging that the loss of the distribution line is abnormal; if not, the loss of the distribution line is normal.
10. The distribution line fault detection and identification method based on two-terminal information acquisition as claimed in claim 9, wherein the specific method for determining the fault type of the distribution line is as follows:
firstly, extracting the amplitude of a phase voltage signal at the head end of the distribution line;
secondly, constructing an envelope curve according to the amplitude of the phase voltage signal at the head end of the distribution line;
thirdly, calculating the slope value of each point on the envelope curve between two adjacent positive amplitude points in real time;
thirdly, calculating the average value of the slope values;
finally, judging whether the slope value average value is larger than a slope reference value or not, if so, generating instantaneous ground fault on the distribution line; if not, a permanent ground fault occurs on the distribution line.
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CN117388641A (en) * | 2023-12-11 | 2024-01-12 | 武汉邢仪新未来电力科技股份有限公司 | Line fault remote monitoring system based on distributed internet of things terminal |
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Publication number | Priority date | Publication date | Assignee | Title |
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CN117388641A (en) * | 2023-12-11 | 2024-01-12 | 武汉邢仪新未来电力科技股份有限公司 | Line fault remote monitoring system based on distributed internet of things terminal |
CN117388641B (en) * | 2023-12-11 | 2024-03-08 | 武汉邢仪新未来电力科技股份有限公司 | Line fault remote monitoring system based on distributed internet of things terminal |
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