CN113176475A - Distributed power supply power transmission and distribution line fault detection method - Google Patents
Distributed power supply power transmission and distribution line fault detection method Download PDFInfo
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- CN113176475A CN113176475A CN202110618089.8A CN202110618089A CN113176475A CN 113176475 A CN113176475 A CN 113176475A CN 202110618089 A CN202110618089 A CN 202110618089A CN 113176475 A CN113176475 A CN 113176475A
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- 238000001514 detection method Methods 0.000 title claims abstract description 13
- 230000005350 ferromagnetic resonance Effects 0.000 claims abstract description 4
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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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- 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
- G01R31/088—Aspects of digital computing
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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 invention provides a distributed power supply power transmission and distribution line fault detection method, which comprises the following steps: (1): collecting signals; (2): judging whether one phase voltage of the three-phase voltage is reduced and is smaller than a voltage reference value, and the other two phases of voltage are increased and are smaller than a line voltage reference value, if so, going to (3); no, to (1); (3): judging whether the zero sequence current is larger than zero, if so, to (4); no, to (8); (4): calculating the phase difference between the zero sequence voltage and the current; (5): calculating the average value of the phase difference in the sampling period; (6): judging whether the average values of the three-phase differences are all less than 0 degrees, if so, judging that the power frequency ferromagnetic resonance faults occur; no, to (7); (7): the phase difference average value is more than 0 degrees, and the corresponding phase has a fault; (8): and continuously analyzing and judging based on the zero sequence current signal. The invention provides a distributed power supply power transmission and distribution line fault detection method which can accurately judge whether a power transmission and distribution line has a fault and the specific fault type.
Description
Technical Field
The invention belongs to the technical field of electric power detection, and particularly relates to a distributed power supply power transmission and distribution line fault detection method.
Background
With the consumption of traditional energy and the consequent environmental problems becoming more serious, people begin to pay attention to the use of new clean energy, distributed power sources composed of solar power generation, wind power generation and the like are widely used by people, and are directly involved in power distribution work by combining with the existing power system.
The power transmission and distribution line is used as an electric energy carrier part directly connected with power consumers in the power system, and the safe and reliable work of the power transmission and distribution line plays an important role in the normal work of the whole power system. When a power transmission and distribution line has a fault, the power consumption of a power consumer is affected, and even a power system fault is caused, so that the fault needs to be found and removed as soon as possible. The distributed power transmission and distribution line has a fault, which is different from the traditional transmission and distribution line, and therefore, a new method is needed for detection.
The invention provides a distributed power supply power transmission and distribution line fault detection method which can accurately judge whether a power transmission and distribution line has a fault and a specific fault type so as to better process the fault.
Disclosure of Invention
The invention provides a distributed power supply power transmission and distribution line fault detection method which can accurately judge whether a power transmission and distribution line has a fault and the specific fault type.
The invention specifically relates to a distributed power supply power transmission and distribution line fault detection method, which comprises the following steps:
step (1): acquiring a zero-sequence voltage signal, a zero-sequence current signal and a three-phase voltage signal of the power transmission and distribution line;
step (2): judging whether one-phase voltage signal of the three-phase voltage signals is reduced and is smaller than a voltage reference value or not, and the other two-phase voltage signals are increased and are smaller than the voltage reference value, if so, entering the step (3); if not, returning to the step (1);
and (3): judging whether the zero sequence current signal is larger than zero, if so, entering the step (4); if not, entering the step (8);
and (4): calculating the phase difference between the zero sequence voltage signal and the zero sequence current signal;
and (5): calculating the average value of the phase difference in the sampling period;
and (6): judging whether the average phase differences of the three phases are all smaller than 0 degree, if so, generating power frequency ferromagnetic resonance fault on the power transmission and distribution line; if not, a single-phase earth fault occurs, and entering the step (7);
and (7): calculating all extreme points of the zero sequence current signal;
and (8): fitting an upper envelope line and a lower envelope line according to the extreme points by utilizing a cubic spline function;
and (9): calculating the mean values of the upper envelope line and the lower envelope line;
step (10): calculating the difference value between the zero sequence current signal and the mean value of the upper envelope line and the lower envelope line;
step (11): judging whether the difference value meets an IMF condition, if not, entering a step (12); if yes, entering step (13);
step (12): defining i (t) -h (t), i (t) being the zero sequence current signal, and h (t) being the difference value of the upper envelope and the lower envelope mean, and returning to the step (7);
step (13): calculating to obtain an IMF component IMF (t) ═ h (t), a residual component r ═ i (t) — (t), an IMF (t), and r;
step (14): calculating the polarity of the IMF component: diff (IMF (t))
Step (15): judging whether the polarity of the IMF component is opposite to that of the IMF components of other phases or not, if so, taking a phase line with the opposite polarity of the IMF component as a ground fault line; if not, the power transmission and distribution line is a bus grounding fault line.
The algorithm for calculating the phase difference between the zero sequence voltage signal and the zero sequence current signal is
Wherein I (t) ═ I sin [ ω t + θi(t)]，u(t)＝U sin[ωt+θu(t)]，
The IMF conditions in the step (11) are as follows:
in the whole data segment, the number of the maximum values and the minimum values is the same as the number of zero-crossing points or differs by one at most; at any time, the mean of the upper envelope and the lower envelope is zero at any point.
Drawings
Fig. 1 is a working flow chart of a distributed power supply power transmission and distribution line fault detection method of the present invention.
Fig. 2 is a working flow chart of the method for determining whether a fault exists in the power transmission and distribution line based on the zero sequence current signal analysis.
Detailed Description
The following describes in detail a specific embodiment of the distributed power transmission and distribution line fault detection method according to the present invention with reference to the accompanying drawings.
As shown in fig. 1, the method for detecting a fault of a distributed power transmission and distribution line of the present invention includes the following steps:
step (1): acquiring a zero-sequence voltage signal, a zero-sequence current signal and a three-phase voltage signal of the power transmission and distribution line;
step (2): judging whether one-phase voltage signal of the three-phase voltage signals is reduced and is smaller than a voltage reference value or not, and the other two-phase voltage signals are increased and are smaller than the voltage reference value, if so, entering the step (3); if not, returning to the step (1);
and (3): judging whether the zero sequence current signal is larger than zero, if so, entering the step (4); if not, entering the step (8);
and (4): calculating the phase difference between the zero sequence voltage signal and the zero sequence current signal
Wherein I (t) ═ I sin [ ω t + θi(t)]，u(t)＝U sin[ωt+θu(t)]，
And (5): calculating the average value of the phase difference in the sampling period;
and (6): judging whether the average phase differences of the three phases are all smaller than 0 degree, if so, generating power frequency ferromagnetic resonance fault on the power transmission and distribution line; if not, a single-phase earth fault occurs, and entering the step (7);
and (7): whether the power transmission and distribution line has a fault or not is judged based on the zero sequence current signal analysis, as shown in fig. 2, the method includes:
(1) calculating all extreme points of the zero sequence current signal;
(2): fitting an upper envelope line and a lower envelope line according to the extreme points by utilizing a cubic spline function;
(3): calculating the mean values of the upper envelope line and the lower envelope line;
(4): calculating the difference value between the zero sequence current signal and the mean value of the upper envelope line and the lower envelope line;
(5): the IMF conditions were: in the whole data segment, the number of the maximum values and the minimum values is the same as the number of zero-crossing points or differs by one at most; at any time, the mean of the upper envelope and the lower envelope is zero at any point.
Judging whether the difference value meets the IMF condition or not, if not, entering (6); if yes, entering (7);
(6): defining i (t) as i (t) -h (t), i (t) as the zero sequence current signal, and h (t) as the difference value of the upper envelope and the lower envelope mean, and returning to (1);
(7): calculating to obtain an IMF component IMF (t) ═ h (t), a residual component r ═ i (t) — (t), an IMF (t), and r;
(8): calculating the polarity of the IMF component: diff (IMF (t))
(9): judging whether the polarity of the IMF component is opposite to that of the IMF components of other phases or not, if so, taking a phase line with the opposite polarity of the IMF component as a ground fault line; if not, the power transmission and distribution line is a bus grounding fault 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 (3)
1. The fault detection method for the distributed power supply power transmission and distribution line is characterized by comprising the following steps of:
step (1): acquiring a zero-sequence voltage signal, a zero-sequence current signal and a three-phase voltage signal of the power transmission and distribution line;
step (2): judging whether one-phase voltage signal of the three-phase voltage signals is reduced and is smaller than a voltage reference value or not, and the other two-phase voltage signals are increased and are smaller than the voltage reference value, if so, entering the step (3); if not, returning to the step (1);
and (3): judging whether the zero sequence current signal is larger than zero, if so, entering the step (4); if not, entering the step (8);
and (4): calculating the phase difference between the zero sequence voltage signal and the zero sequence current signal;
and (5): calculating the average value of the phase difference in the sampling period;
and (6): judging whether the average phase differences of the three phases are all smaller than 0 degree, if so, generating power frequency ferromagnetic resonance fault on the power transmission and distribution line; if not, a single-phase earth fault occurs, and entering the step (7);
and (7): calculating all extreme points of the zero sequence current signal;
and (8): fitting an upper envelope line and a lower envelope line according to the extreme points by utilizing a cubic spline function;
and (9): calculating the mean values of the upper envelope line and the lower envelope line;
step (10): calculating the difference value between the zero sequence current signal and the mean value of the upper envelope line and the lower envelope line;
step (11): judging whether the difference value meets an IMF condition, if not, entering a step (12); if yes, entering step (13);
step (12): defining i (t) -h (t), i (t) being the zero sequence current signal, and h (t) being the difference value of the upper envelope and the lower envelope mean, and returning to the step (7);
step (13): calculating to obtain an IMF component IMF (t) ═ h (t), a residual component r ═ i (t) — (t), an IMF (t), and r;
step (14): calculating the polarity of the IMF component: diff (IMF (t))
Step (15): judging whether the polarity of the IMF component is opposite to that of the IMF components of other phases or not, if so, taking a phase line with the opposite polarity of the IMF component as a ground fault line; if not, the power transmission and distribution line is a bus grounding fault line.
2. The method of claim 1, wherein the algorithm for calculating the phase difference between the zero-sequence voltage signal and the zero-sequence current signal comprises
Wherein i (t) Isin [ ω t + θ [ ]i(t)]，u(t)＝Usin[ωt+θu(t)]，
3. The method according to claim 2, wherein the IMF condition in step (11) is:
in the whole data segment, the number of the maximum values and the minimum values is the same as the number of zero-crossing points or differs by one at most; at any time, the mean of the upper envelope and the lower envelope is zero at any point.
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| CN117706279A (en) * | 2024-02-05 | 2024-03-15 | 青岛鼎信通讯科技有限公司 | Phase failure fault diagnosis method for low-voltage distribution system |
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Application publication date: 20210727 |