CN112379220B - Ground fault positioning system and method based on distribution transformer injection pulse - Google Patents
Ground fault positioning system and method based on distribution transformer injection pulse Download PDFInfo
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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
- G01R31/11—Locating faults in cables, transmission lines, or networks using pulse reflection methods
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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
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
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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
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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- 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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Abstract
The invention relates to a grounding fault positioning system and method based on distribution transformer injection pulse, the system includes signal generating device, discharge detection sensor, selective grounding device and fault positioning device; the signal generating device is connected with a neutral point n on the low-voltage side of the distribution transformer in a common ground manner; after being connected in parallel, a certain two phases at the low-voltage side of the distribution transformer are connected with the output end of the signal generator; an A, B, C port of the discharge detection sensor is connected in parallel with a A, B, C port of the selective grounding device and is correspondingly connected to an A phase, a B phase and a C phase of the high-voltage side of the distribution transformer respectively; the discharge detection sensor comprises a signal acquisition module and a signal transmission module which are connected, and is used for acquiring and transmitting signals to the fault positioning device. The invention has the advantages of less equipment required in the line selection and distance measurement process and simple steps, greatly lightens the burden of operation and maintenance personnel, shortens the troubleshooting time, and effectively improves the power supply reliability and the intelligent level of a power grid.
Description
Technical Field
The invention belongs to the technical field of single-phase earth fault detection and positioning, and particularly relates to a line single-phase earth fault positioning system and method based on pulse signal injection at the low-voltage side of a distribution transformer.
Background
The continuous development of power distribution networks makes users have higher requirements on the reliability and quality of power supply. This means that once the distribution network fails, the power supply company needs to find out the location where the failure occurs as soon as possible so as to put forward a coping strategy in time to recover the power supply to the user, thereby ensuring the rapid recovery of production and life. At present, a 10kV distribution network system has multiple branches and a complex structure, and is easy to generate single-phase earth faults.
Currently, the following problems mainly exist in power distribution network fault location: the fault indicator is unreasonable in configuration, unstable in power supply of a power supply and unreliable in remote transmission mode, so that when the fault is located and isolated by using the reclosing breaker and the fault indicator, the device frequently makes a misjudgment and refuses to operate, and the actual effect is not obvious. Secondly, the accuracy of fault judgment of the low-current grounding line selection device is low; and single-phase earth faults occur frequently, account for more than 70% of the total number of the faults of the distribution network, and the accuracy of single-phase earth fault positioning needs to be improved.
Disclosure of Invention
The invention aims to solve the defects of the prior art, and provides a distribution transformer injection pulse-based ground fault positioning system and method, which solve the problems that equipment in the prior art is inconvenient to carry and install, have high stability, are easy to realize functions, do not need a large amount of analysis data, and have high applicability.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
ground fault positioning system based on distribution transformer injection pulse includes: the device comprises a signal generating device, a discharge detection sensor, a selective grounding device and a fault positioning device;
the signal generating device is connected with a neutral point n on the low-voltage side of the distribution transformer in a common ground mode; after being connected in parallel, a certain two phases at the low-voltage side of the distribution transformer are connected with the output end of the signal generator; the signal generating device is used for injecting pulse signals;
the A, B, C port of the discharge detection sensor is connected in parallel with the A, B, C port of the selective grounding device and is correspondingly connected to the phase A, the phase B and the phase C on the high-voltage side of the distribution transformer respectively;
the discharge detection sensor comprises a signal acquisition module and a signal transmission module which are connected with each other; the signal acquisition module is used for acquiring pulse signals; the signal transmission module is used for transmitting the signals acquired by the signal acquisition module to the fault positioning device;
the fault positioning device is used for analyzing according to the signals transmitted by the signal transmission module so as to position the fault.
Further, it is preferable that the distribution transformer is coupled with Dyn 11.
Further, preferably, the signal transmission module is configured to transmit the signal acquired by the signal acquisition module to the fault location device in a wireless or wired transmission manner.
The invention also provides a ground fault positioning method based on the distribution transformer injection pulse, and the ground fault positioning system based on the distribution transformer injection pulse comprises the following steps:
step (1), setting the state of the selective grounding device, and randomly grounding one phase of A phase, B phase and C phase directly;
step (2), the signal generating device injects a voltage amplitude value of equal to a certain two phases at the low-voltage side of the distribution transformer according to a certain injection ruleU 0The pulse signal of (3);
step (3), the discharge detection sensor detects a voltage signal of the high-voltage side of the distribution transformer, and then transmits the acquired signal to a fault positioning device;
step (4), the fault positioning device analyzes signals obtained by detection of the discharge detection sensor and judges whether second pulses exist in each phase or not;
step (5), when the state of the selective grounding device is x-phase direct grounding, x = A, B or C, if the waveform of each phase has no second pulse, the single-phase grounding fault is judged to be x-phase; if the second pulse exists, returning to the step (1) to change the state of the selective grounding device again;
step (6), when the single-phase earth fault is judged to be in the phase A, operating the selective earthing device to enable the phase B or the phase C to be directly earthed; when the single-phase earth fault is judged to be in the phase C, operating the selective earthing device to enable the phase A or the phase B to be directly earthed; when the single-phase earth fault is judged to be in the B phase, the selective earthing device is operated to enable the A phaseOr the phase C is directly grounded; then the signal generating device injects the voltage amplitude value of the same time to a certain two phases at the low-voltage side of the distribution transformer according to a certain injection ruleU 0The pulse signal of (3);
and (7) detecting the signal characteristics of the fault phase, and recording the time corresponding to the first pulse amplitude and the second pulse amplitude as the time respectively
And
and carrying out fault location by using the time difference.
Further, in the steps (2) and (7), the injection rule is preferably: when the state of the selective grounding device is that the phase A is directly grounded, the low-voltage side A, C of the distribution transformer is injected in parallel; when the state of the selective grounding device is that the phase B is directly grounded, the low-voltage side A, B of the distribution transformer is injected in parallel; when the selective grounding device is in a state of direct grounding of the phase C, the low voltage side B, C of the distribution transformer is connected in parallel.
Further, it is preferable that the second pulse is discriminated as follows:
calculating and judging by using two ungrounded phases of the selectable grounding device: multiplying the ungrounded two-phase waveform by a coefficient of-1; and then judging the part of the two-phase waveforms which are not overlapped after the multiplication by the coefficient-1, wherein the time period corresponding to the first non-overlapped part is the time period corresponding to the second pulse of the fault phase, and judging the pulse on the fault phase in the time period to be the second pulse.
Further, it is preferable that, if the line is not branched, the line is directly positioned according to the time difference between the first pulse and the second pulse; if the line has one or more branches, determining the fault branch according to a removing method;
the absence of pulses in the present invention generally means: 1/2 with amplitudes less than the amplitudes of the pulses in the other same time periods are considered pulse-free.
The elimination method utilizes the time difference between the amplitudes of the second pulse and the third pulse to calculate the length of the overhead line as the length of a side branch with a common fulcrum with a branch where a fault point is located; and according to the characteristic of the length of the side branch, excluding other lines with the same length as the length calculated by the time difference of the first pulse amplitude and the second pulse amplitude.
In the invention, the first pulse is the first pulse of the measured signal, namely the signal coupled to the high-voltage side after the low-voltage side is injected. The second pulse is a signal reflected by a fault point after traveling waves on two phases which are not grounded by the selective grounding device meet a single-phase grounding fault.
The present invention exemplifies the method for determining the second pulse and the third pulse, for example, if the ungrounded phases of the selective grounding device are the a phase and the C phase, the waveform of the a phase or the C phase is multiplied by a coefficient-1, and is marked as a 'and C'; then, the part where A 'and C' are not overlapped is judged, and the pulse on the time period corresponding to the first non-overlapped part is the second pulse. The pulse in the time period corresponding to the 2 nd misaligned small segment is the third pulse.
According to the invention, certain two phases at the low-voltage side of the Dyn11 distribution transformer are connected in parallel, pulse signals are injected, and meanwhile, each phase at the high-voltage side of the distribution transformer is selectively and directly grounded. By utilizing the electromagnetic transmission characteristic of the distribution transformer, the injected pulse signals are coupled to three phases of the high-voltage side and amplified, and different phases of the high-voltage side are grounded, so that the ground signals detected by the high-voltage side can be further amplified. The amplified pulse signal is transmitted on a line, and is refracted and reflected when meeting a fault point, and the fault signal is transmitted back to the distribution transformer and influences the three-phase waveform. The discharge detection sensor is used for measuring signals of all phases at the high-voltage side of the distribution transformer, and fault line selection can be completed according to the waveform characteristics of all detected signals. According to the time difference between the first pulse signal and the second pulse signal of the fault phase, the measurement of the fault distance can be realized, and thus the single-phase earth fault positioning is realized.
Compared with the prior art, the invention has the beneficial effects that:
the invention is based on the electromagnetic transmission characteristic of a Dyn11 distribution transformer, pulse signals are injected from a certain two phases of a low-voltage side and coupled to a high-voltage side, and each phase of the high-voltage side is selectively and directly grounded, so that the signal can be amplified to improve the signal detectability, and the fault phase selection can be carried out by utilizing the waveform characteristic of the signal of the high-voltage side. And after phase selection, the fault distance is calculated and calculated by taking the time difference of the pulse signals detected by the high-voltage side fault phase as a basis, and manual distance measurement is not involved. The whole line selection and ranging process needs few equipment, has simple steps, greatly lightens the burden of operation and maintenance personnel, shortens troubleshooting time, and effectively improves the power supply reliability and the intelligent level of a power grid.
The existing fault location strategy needs to manually locate the fault along the line by a handheld device after injecting a low-voltage signal; or a high-voltage source which is complex in circuit, large in size, heavy and inconvenient to carry needs to be designed to inject high-voltage pulse signals, and then positioning is carried out through the wave catadioptric principle; or complex algorithms need to be designed to identify the fault signal for location. The method solves the problem that the equipment in the prior art is inconvenient to carry and install, is easy to realize in function, does not need to analyze a large amount of data and design a complex algorithm, and has higher applicability and convenience.
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, and 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 these drawings without creative efforts.
FIG. 1 is a schematic diagram of a distribution transformer injection pulse based ground fault location system wiring configuration of the present invention;
FIG. 2 is a flow chart of a method for locating a ground fault based on injection pulses of a distribution transformer in accordance with the present invention;
FIG. 3 is a simulation schematic diagram of single-phase earth fault location of a 10kV distribution overhead line system;
fig. 4 is a simulation result diagram.
Detailed Description
The present invention will be described in further detail with reference to examples.
It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The materials or equipment used are not indicated by manufacturers, and all are conventional products available by purchase.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. Further, "connected" as used herein may include wirelessly connected. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
In the description of the present invention, "a plurality" means two or more unless otherwise specified. The terms "inner," "upper," "lower," and the like, refer to an orientation or a state relationship based on that shown in the drawings, which is for convenience in describing and simplifying the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "provided" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. To those of ordinary skill in the art, the specific meanings of the above terms in the present invention are understood according to specific situations.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
As shown in fig. 1, a distribution transformer injection pulse based ground fault location system includes: the device comprises a signal generating device, a discharge detection sensor, a selective grounding device and a fault positioning device;
the signal generating device is located at a position marked as 2 and is connected with a low-voltage side neutral point n of the distribution transformer at the position 1 in a common ground manner; after being connected in parallel, a certain two phases at the low-voltage side of the distribution transformer are connected with the output end of the signal generator; the signal generating device is used for injecting pulse signals;
an A, B, C port of the discharge detection sensor is connected in parallel with a A, B, C port of the selective grounding device, and is correspondingly connected to an A phase, a B phase and a C phase of the high-voltage side of the distribution transformer respectively, and the access point is marked as position 3;
the discharge detection sensor comprises a signal acquisition module and a signal transmission module which are connected with each other; the signal acquisition module is used for acquiring pulse signals; the signal transmission module is used for transmitting the signals acquired by the signal acquisition module to the fault positioning device at the position 4;
the fault positioning device is used for analyzing according to the signals transmitted by the signal transmission module so as to position the fault.
Referring to fig. 2, a flowchart of a method for locating a ground fault based on an injection pulse of a distribution transformer according to the present invention is shown; as can be seen from fig. 2, the present embodiment provides a ground fault location based on injection pulses of a distribution transformer, and the method includes:
installing a discharge detection sensor and a selective grounding device on the high-voltage side of the distribution transformer according to the positions marked in the figure 1;
the selective grounding device is arbitrarily set to be directly grounded on a certain phase;
according to a certain injection rule on the low-voltage side of the distribution transformer, the injection amplitude of a certain two-phase of the distribution transformer isU 0The pulse signal of (3); specifically, when the state of the selective grounding device is that the phase A is directly grounded, the low-voltage side A, C of the distribution transformer is connected in parallel and a pulse signal is injected; when the state of the selective grounding device is that the phase B is directly grounded, the low-voltage sides A, B of the distribution transformers are connected in parallel and pulse signals are injected; when the state of the selective grounding device is that the phase C is directly grounded, the low-voltage side B, C of the distribution transformer is connected in parallel and a pulse signal is injected; the pulse signal generating device is positioned as shown in figure 1;
judging the peak values and the corresponding intervals of a first pulse and a second pulse of a high-voltage side pulse signal of the distribution transformer detected by each phase discharge detection sensor; specifically, the first pulse is the first pulse of the measured signal, i.e., the signal coupled to the high side after the low side injection. The second pulse is a signal reflected by a fault point after traveling waves on a fault phase meet a single-phase earth fault; the second pulse discrimination method needs to use two phases which are not grounded by the selective grounding device for calculation and judgment: for example, if the ungrounded phases of the selective grounding device are the A phase and the C phase, the waveform of the A phase or the C phase is multiplied by a coefficient of-1 and is marked as A 'and C'; then, the part where A 'and C' are not overlapped is judged, and the time period corresponding to the first non-overlapped part is the second pulse.
If the second pulse does not exist, directly judging that the direct grounding phase of the selective grounding device is a fault phase;
if the second pulse exists, directly judging that the ungrounded phase of the selective grounding device is a fault phase, replacing the direct grounding phase of the selective direct grounding device until the ungrounded phase of the selective grounding device does not have the second pulse, and judging that the grounding phase of the selective grounding device at the moment is the fault phase;
after the fault phase is determined, the direct grounding phase of the selective grounding device is changed;
according to a certain injection rule again, the injection amplitude isU 0The pulse signal of (3); specifically, when the state of the selective grounding device is that the phase A is directly grounded, the low-voltage side A, C of the distribution transformer is connected in parallel and a pulse signal is injected; when the state of the selective grounding device is that the phase B is directly grounded, the low-voltage sides A, B of the distribution transformers are connected in parallel and pulse signals are injected; when the state of the selective grounding device is that the phase C is directly grounded, the low-voltage side B, C of the distribution transformer is connected in parallel and a pulse signal is injected; the pulse signal generating device is positioned as shown in figure 1;
judging the peak values and the corresponding intervals of a first pulse and a second pulse of the pulse signal detected by each phase discharge detection sensor; specifically, the first pulse is the first pulse of the measured signal, i.e., the signal coupled to the high side after the low side injection. The second pulse is a signal reflected by a fault point after traveling waves on a fault phase meet a single-phase earth fault; the second pulse discrimination method needs to use two phases which are not grounded by the selective grounding device for calculation and judgment: for example, if the ungrounded phases of the selective grounding device are the A phase and the C phase, the waveform of the A phase or the C phase is multiplied by a coefficient of-1 and is marked as A 'and C'; then judging the part where A 'and C' are not overlapped, wherein the pulse on the time period corresponding to the first non-overlapped part is the second pulse;
reading the signal characteristics of the fault phase, and positioning by using the time difference of the first pulse, the second pulse and the third pulse; specifically, if the line is simple and has no branches, the positioning can be directly carried out according to the time difference between the first pulse and the second pulse; if the line is complicated and has one or more branches, determining the fault branch according to a removing method; the elimination method utilizes the time difference of the amplitude values of the second pulse and the third pulse; the third pulse judging method is the same as the second pulse except that the third pulse is a 2 nd non-coincident small section in a non-coincident part of A 'and C' (taking the non-grounded phase of the selective grounding device as an example of A, C); and the length of the overhead line obtained by calculating the time difference between the amplitudes of the second pulse and the third pulse is the length of a side branch with a common fulcrum in the branch where the fault point is located. According to the characteristic of the length of the side branch, other lines with the same length as the length calculated by the time difference of the first pulse amplitude and the second pulse amplitude can be excluded.
The specific calculation formula for positioning by using the time difference is as follows:
wherein the content of the first and second substances,Lthe distance between the line fault point and the distribution transformer is calculated, and c is the light speed value of 3 multiplied by 108m/s, the time corresponding to the first pulse amplitude and the second pulse amplitude ist 1Andt 2。
simulation example:
the simulation of single-phase earth fault location in a 10kV distribution overhead line system by using the method provided by the invention is shown in figure 3. Wherein, a rectangular signal simulation circuit with the amplitude of 400V is selected as a voltage source and corresponds to a signal generating device at the position 2 in practice; distribution transformer P _ transf corresponds to the Dyn11 distribution transformer at position 1 in practice; TLine _1 with the length of 5km is connected to the high-voltage side of a distribution transformer P _ transf, and then is divided into two lines: TLine _2 with the length of 100km and TLine _3 with the length of 3.5km, wherein a single-phase ground fault (grounded through a 1-ohm resistor in the figure) which is 2km away from a branch point on the TLine _2 divides the TLine _2 into TLine _11 and TLine _12, and a C-phase fault is simulated in simulation; voltage to ground measured by high-voltage side of distribution transformer in simulationE A、E BAndE Cthe voltage signals of the high-voltage side of the distribution transformer detected by the discharge detection sensor at the actual middle position 3 are respectively corresponded; the direct grounding in the simulation represents the state of the selective grounding device, and the direct grounding of the phase A in the simulation represents that the state of the selective grounding device is actually the direct grounding of the phase A. According to the initial state of the selectable grounding device and according to the certain injection rule, the low-voltage side A, C of the distribution transformer P _ transf is connected in parallel to a voltage source represented by a rectangular signal simulation circuit, a pulse signal with the amplitude of 400V is injected, and the simulation result is as shown in figure 4Shown in the figure.
According to the simulation result and the single-phase earth fault positioning method based on the injection of the pulse signal at the low-voltage side of the distribution transformer: judging that each phase has a second pulse according to the first pulse and second pulse judging method, and judging that the fault is in a B or C phase; and then changing the state of the selective grounding device into C-phase grounding, injecting signals according to the certain injection rule, and judging that the fault phase is in the C-phase if no second pulse exists in the simulation result. Step (6) is then performed, where the alternative grounding device is selected to be phase a grounded, and the initial simulation results of fig. 4 may be used. Next, step (7) is performed according to FIG. 4, and the signal characteristics of the failed phase C phase are read, wherein the time corresponding to the first pulse amplitude and the second pulse amplitude is t1=11.06 μ s and t2=57.59 μ s, substituting the time difference positioning calculation formula to calculate L =6.980km, and the error is 0.020 km; the method further comprises the steps of determining a fault branch according to a removing method and judging a third pulse to read information according to a judging method of the third pulse because a line is complex and has branches, wherein the time corresponding to the amplitude of the third pulse is t3=82.26 μ s; the length of the side branch calculated by the time difference between the amplitudes of the second pulse and the third pulse is L' =3.551km, and the length is close to the actual length of TLine _3, namely 3.5km, so that the TLine _3 is judged to be the side branch, and the fault is on TLine _ 2. Finally, a fault point which is 0.020km away from the transformer 6.980km on TLine _2 is determined.
As can be seen from the example, the fault positioning effect obtained by the method provided by the invention is good, and the error is small. And can use the less pulse to inject the voltage and obtain the greater detectable trouble voltage signal, can avoid the manual work to patrol and examine or must carry the heavy, difficult problem of carrying the high voltage power supply that is portable when the traditional injection method is positioned. According to the method, the grounding fault signal is easy to identify and judge, a complex algorithm does not need to be designed, and the method has high practical value.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (5)
1. The ground fault positioning method based on distribution transformer injection pulse is characterized in that a ground fault positioning system based on distribution transformer injection pulse is adopted, and the ground fault positioning system based on distribution transformer injection pulse comprises the following steps: the device comprises a signal generating device, a discharge detection sensor, a selective grounding device and a fault positioning device;
the signal generating device is connected with a neutral point n on the low-voltage side of the distribution transformer in a common ground mode; after being connected in parallel, a certain two phases at the low-voltage side of the distribution transformer are connected with the output end of the signal generator; the signal generating device is used for injecting pulse signals;
the A, B, C port of the discharge detection sensor is connected in parallel with the A, B, C port of the selective grounding device and is correspondingly connected to the phase A, the phase B and the phase C on the high-voltage side of the distribution transformer respectively;
the discharge detection sensor comprises a signal acquisition module and a signal transmission module which are connected with each other; the signal acquisition module is used for acquiring pulse signals; the signal transmission module is used for transmitting the signals acquired by the signal acquisition module to the fault positioning device;
the fault positioning device is used for analyzing according to the signal transmitted by the signal transmission module so as to position the fault;
the ground fault positioning method based on the injection pulse of the distribution transformer comprises the following steps:
step (1), setting the state of the selective grounding device, and randomly grounding one phase of A phase, B phase and C phase directly;
step (2), the signal generating device injects a voltage amplitude value of equal to a certain two phases at the low-voltage side of the distribution transformer according to a certain injection ruleU 0The pulse signal of (3);
step (3), the discharge detection sensor detects a voltage signal of the high-voltage side of the distribution transformer, and then transmits the acquired signal to a fault positioning device;
step (4), the fault positioning device analyzes signals obtained by detection of the discharge detection sensor and judges whether second pulses exist in each phase or not;
step (5), when the state of the selective grounding device is x-phase direct grounding, x = A, B or C, if the waveform of each phase has no second pulse, the single-phase grounding fault is judged to be x-phase; if the second pulse exists, returning to the step (1) to change the state of the selective grounding device again;
step (6), when the single-phase earth fault is judged to be in the phase A, operating the selective earthing device to enable the phase B or the phase C to be directly earthed; when the single-phase earth fault is judged to be in the phase C, operating the selective earthing device to enable the phase A or the phase B to be directly earthed; when the single-phase earth fault is judged to be in the phase B, operating the selective earthing device to enable the phase A or the phase C to be directly earthed; then the signal generating device injects the voltage amplitude value of the same time to a certain two phases at the low-voltage side of the distribution transformer according to a certain injection ruleU 0The pulse signal of (3);
and (7) detecting the signal characteristics of the fault phase, and recording the time corresponding to the first pulse amplitude and the second pulse amplitude as the time respectively
And
carrying out fault positioning by using the time difference;
the second pulse discrimination method is as follows:
calculating and judging by using two ungrounded phases of the selectable grounding device: multiplying the ungrounded two-phase waveform by a coefficient of-1; and then judging the part of the two-phase waveforms which are not overlapped after the multiplication by the coefficient-1, wherein the time period corresponding to the first non-overlapped part is the time period corresponding to the second pulse of the fault phase, and judging the pulse on the fault phase in the time period to be the second pulse.
2. The method of claim 1 wherein the distribution transformer is coupled using Dyn 11.
3. The distribution transformer injection pulse-based ground fault location method of claim 1, wherein the signal transmission module is configured to transmit the signal acquired by the signal acquisition module to the fault location device in a wireless or wired transmission manner.
4. The method for locating a ground fault based on injection pulses of a distribution transformer according to claim 1, wherein in the steps (2) and (7), the injection rule is as follows: when the state of the selective grounding device is that the phase A is directly grounded, the low-voltage side A, C of the distribution transformer is injected in parallel; when the state of the selective grounding device is that the phase B is directly grounded, the low-voltage side A, B of the distribution transformer is injected in parallel; when the selective grounding device is in a state of direct grounding of the phase C, the low voltage side B, C of the distribution transformer is connected in parallel.
5. The method of claim 1, wherein if the line is unbranched, the method directly locates the ground fault based on a time difference between the first pulse and the second pulse; if the line has one or more branches, determining the fault branch according to a removing method;
the elimination method utilizes the time difference between the amplitudes of the second pulse and the third pulse to calculate the length of the overhead line as the length of a side branch with a common fulcrum with a branch where a fault point is located; according to the characteristic of the length of the side branch, other lines with the same length as the length calculated by the time difference of the first pulse amplitude and the second pulse amplitude are excluded;
the third pulse is determined as follows:
calculating and judging by using two ungrounded phases of the selectable grounding device: multiplying the ungrounded two-phase waveform by a coefficient of-1; and then judging the part of the two-phase waveform which is not coincident after multiplying by the coefficient-1, wherein the time period corresponding to the second non-coincident part is the time period corresponding to the third pulse of the fault phase, and judging the pulse on the fault phase in the time period to be the third pulse.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002350489A (en) * | 2001-05-29 | 2002-12-04 | Nippon Kouatsu Electric Co | Fault point position plotting method and device for high voltage distribution line |
| CN202041559U (en) * | 2011-04-22 | 2011-11-16 | 上海市电力公司 | Signal source equipment for power transmission line grounding fault automatic positioning device |
| CN203324404U (en) * | 2013-06-27 | 2013-12-04 | 国家电网公司 | Test circuit for small current grounding line selection device |
| CN110161353A (en) * | 2019-04-30 | 2019-08-23 | 云南电网有限责任公司电力科学研究院 | A kind of fault locator and method |
| CN110161358A (en) * | 2019-04-30 | 2019-08-23 | 云南电网有限责任公司电力科学研究院 | A kind of Earth design method and device |
| CN111175610A (en) * | 2020-02-06 | 2020-05-19 | 云南电网有限责任公司电力科学研究院 | Fault positioning system and method for distribution line |
-
2020
- 2020-10-27 CN CN202011168047.0A patent/CN112379220B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002350489A (en) * | 2001-05-29 | 2002-12-04 | Nippon Kouatsu Electric Co | Fault point position plotting method and device for high voltage distribution line |
| CN202041559U (en) * | 2011-04-22 | 2011-11-16 | 上海市电力公司 | Signal source equipment for power transmission line grounding fault automatic positioning device |
| CN203324404U (en) * | 2013-06-27 | 2013-12-04 | 国家电网公司 | Test circuit for small current grounding line selection device |
| CN110161353A (en) * | 2019-04-30 | 2019-08-23 | 云南电网有限责任公司电力科学研究院 | A kind of fault locator and method |
| CN110161358A (en) * | 2019-04-30 | 2019-08-23 | 云南电网有限责任公司电力科学研究院 | A kind of Earth design method and device |
| CN111175610A (en) * | 2020-02-06 | 2020-05-19 | 云南电网有限责任公司电力科学研究院 | Fault positioning system and method for distribution line |
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