CN116087684A - Small-current ground fault segment selection method and device, electronic equipment and storage medium - Google Patents
Small-current ground fault segment selection method and device, electronic equipment and storage medium 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
- G01R31/081—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
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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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- 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
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- 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
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Abstract
The embodiment of the invention provides a small-current ground fault section selection method, a small-current ground fault section selection device, electronic equipment and a storage medium, which comprise the following steps: when detecting that the transformer substation has a low-current ground fault, acquiring alternating current parameters of the transformer substation; the alternating current parameters comprise a current value of a current side three phase and a current value of a current opposite side three phase; calculating split-phase longitudinal differential current according to the current value of the current side and the current value of the current side; calculating an inter-phase difference stream according to the split-phase longitudinal difference stream; and determining a single-phase grounding fault line section according to the phase difference flow. According to the embodiment of the invention, the single-phase grounding fault can be accurately detected, and further the section selection positioning and nearby isolation of the low-current grounding fault are realized.
Description
Technical Field
The invention relates to the technical field of power station fault diagnosis, in particular to a small-current ground fault section selection method, a small-current ground fault section selection device, electronic equipment and a storage medium.
Background
Most of the distribution networks are low-current grounding systems, and single-phase grounding faults account for more than 80% of the total fault quantity. When a single-phase earth fault occurs, the fault current changes little, and the characteristic quantity is not obvious. The existing method for selecting the small-current grounding fault mainly adopts a method for analyzing zero sequence voltage and current at each interval by configuring a small-current grounding line selecting device in a transformer substation, but the existing detection mode has low accuracy, so that the overall line selecting success rate is low, and the distribution line section where the fault is located cannot be determined.
Disclosure of Invention
In view of the foregoing, embodiments of the present invention have been developed to provide a low-current ground fault section selection method, a low-current ground fault section selection apparatus, an electronic device, and a storage medium that overcome or at least partially solve the foregoing problems.
In a first aspect of the present invention, an embodiment of the present invention discloses a small current ground fault segment selection method, which is applied to a power supply master station, where the power supply master station is connected with a plurality of substations, and the method includes:
when detecting that the transformer substation has a low-current ground fault, acquiring alternating current parameters of the transformer substation; the alternating current parameters comprise a current value of a current side three phase and a current value of a current opposite side three phase;
calculating split-phase longitudinal differential current according to the current value of the current side and the current value of the current side;
calculating an inter-phase difference stream according to the split-phase longitudinal difference stream;
and determining a single-phase grounding fault line section according to the phase difference flow.
Optionally, the method further comprises:
acquiring three-phase voltage parameters of the transformer substation; the three-phase voltage parameter comprises a first phase voltage value, a second phase voltage value and a third phase voltage value;
and when two of the first phase voltage value, the second phase voltage value and the third phase voltage value are larger than a preset non-grounding phase voltage setting value and the other is smaller than a preset grounding phase voltage setting value, determining that the substation sends a small-current grounding fault.
Optionally, the method further comprises:
and calculating inter-phase braking current according to the split-phase longitudinal differential flow.
Optionally, the method further comprises:
and when the ratio of the inter-phase braking current to the inter-phase differential current is greater than a preset proportional braking coefficient, executing the step of determining the single-phase grounding fault line section.
Optionally, the current value of the third phase includes a current value of the first phase, a current value of the second phase, and a current value of the third phase, and the current value of the second phase includes a current value of the first phase, a current value of the second phase, and a current value of the third phase; the step of calculating the split-phase longitudinal differential flow according to the current value of the current side three phase and the current value of the opposite side three phase comprises the following steps:
vector addition is carried out on the current value of the first phase at the current side and the current value of the first phase at the current side to obtain a first longitudinal differential stream;
vector addition is carried out on the current value of the second phase at the side and the current value of the second phase at the opposite side, so as to obtain a second-phase longitudinal differential stream;
vector addition is carried out on the current value of the third phase at the current side and the current value of the third phase at the current side to obtain a third longitudinal differential stream;
and determining the first phase longitudinal differential flow, the second phase longitudinal differential flow and the third phase longitudinal differential flow as the split-phase longitudinal differential flow.
Optionally, the step of calculating the phase difference stream according to the split-phase longitudinal differential stream includes:
vector subtraction is carried out on the second phase longitudinal differential stream by adopting the first phase longitudinal differential stream to obtain a first transverse differential stream;
vector subtraction is carried out on the first phase longitudinal differential stream by adopting the second phase longitudinal differential stream to obtain a second transverse differential stream;
vector subtraction is carried out on the second-phase longitudinal differential stream by adopting the third-phase longitudinal differential stream to obtain a third transverse differential stream;
determining the first, second, and third lateral differential streams as the inter-phase differential streams.
Optionally, the step of determining a single phase ground fault line segment according to the phase difference stream comprises:
and when the phase-to-phase difference flow is larger than a preset threshold value, determining the line segment where the current value of the three phases on the side is located as the single-phase grounding fault line segment.
In a second aspect of the present invention, an embodiment of the present invention discloses a small current ground fault section selection device applied to a power supply master station, where the power supply master station is connected to a plurality of substations, the device includes:
the first acquisition module is used for acquiring alternating current parameters of the transformer substation when detecting that the transformer substation has a low-current ground fault; the alternating current parameters comprise a current value of a current side three phase and a current value of a current opposite side three phase;
the first calculation module is used for calculating split-phase longitudinal differential flow according to the current value of the current side three phase and the current value of the current opposite side three phase;
the second calculation module calculates an inter-phase difference stream according to the split-phase longitudinal difference stream;
and the fault determining module is used for determining a single-phase grounding fault line section according to the phase difference flow.
In a third aspect of the present invention, an embodiment of the present invention discloses an electronic device comprising a processor, a memory and a computer program stored on the memory and capable of running on the processor, which when executed by the processor implements the steps of the low current ground fault segmentation method as described above.
In a fourth aspect of the invention, embodiments of the invention disclose a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the low current ground fault segmentation method as described above.
The embodiment of the invention has the following advantages:
according to the embodiment of the invention, when the transformer substation is detected to have a low-current ground fault, the alternating current parameters of the transformer substation are obtained; the alternating current parameters comprise a current value of a current side three phase and a current value of a current opposite side three phase; calculating split-phase longitudinal differential current according to the current value of the current side and the current value of the current side; calculating an inter-phase difference stream according to the split-phase longitudinal difference stream; and determining a single-phase grounding fault line section according to the phase difference flow. By adopting the double-end data analysis and a small-current section selection method based on second-order differential, the accuracy of line selection is greatly improved, meanwhile, the sectional positioning and tripping control of faults are realized, and the power failure range is reduced.
Drawings
FIG. 1 is a flow chart of steps of an embodiment of a small current ground fault segmentation method of the present invention;
FIG. 2 is a flow chart of steps of an embodiment of a low current ground fault segmentation method of the present invention;
FIG. 3 is a schematic diagram of hardware connections of an example of a low current ground fault segmentation method of the present invention;
FIG. 4 is a flow chart of steps of an example low current ground fault segmentation method of the present invention;
fig. 5 is a block diagram of an embodiment of a low current ground fault section device of the present invention.
Detailed Description
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
At present, single-ended data analysis is mostly adopted for the small-current ground fault investigation method, and the precision and wiring accuracy of zero sequence CT (current transformer) and PT (voltage transformer) in a transformer substation are relied on, so that the overall line selection success rate is not high and the requirements are difficult to meet; and arrange the little electric current device in the station and need additionally arrange a large amount of cables, generally each transformer substation need arrange approximately 1000 meters of cable, causes the wasting of resources, also does not accord with the requirement of festival carbon, and construction excavation cost is higher. The single-ended configuration low-current grounding line selection device can only perform switch trial jump in a transformer substation, the distribution line section where a fault is located cannot be determined, the fault isolation range is large, part of areas which do not have faults are isolated, unnecessary power failure is caused, and the accuracy is low.
One of the core invention points of the invention is that when a single-phase earth fault occurs in the system, the three-phase current fault components at the upstream of the fault point are unbalanced, and the three-phase current fault components at the downstream of the fault point are balanced (all are line zero-sequence currents). The distributed acquisition control device sends the electric quantity data to the master station analysis system, the unbalance degree of current fault components at two sides of the line is quantified through plane differential motion, and when the difference between the two sides is large, the fault point is judged to be located on the line section and sent.
Referring to fig. 1, a step flow diagram of an embodiment of a low-current ground fault section selection method of the present invention is shown and applied to a power supply master station, where the power supply master station is connected to a plurality of substations, and the specific low-current ground fault section selection method may include the following steps:
the power supply main station is connected with the busbar voltage in each transformer substation, the power supply main station carries out abnormality judgment through the voltage of each transformer substation, and when the small-current ground fault of the transformer substation is judged and detected, the alternating current parameter of the transformer substation is obtained, and the alternating current parameter is the electrical parameter of each alternating current of the transformer substation. Wherein, alternating current parameters include: the current value of the current side and the current value of the current opposite side. The current value of the three-phase on the side is the current value of the three-phase current flowing in the upstream of the transformer substation, and the current value of the three-phase on the opposite side is the current value of the three-phase current flowing out of the transformer substation to the downstream.
102, calculating split-phase longitudinal differential flow according to the current value of the current side and the current value of the current side;
in the embodiment of the invention, the split-phase longitudinal differential current of the transformer substation is calculated according to the current value of the three phases at the side and the current value of the three phases at the opposite side so as to determine that the circuit at the side has faults, and further the line segment range of fault elimination is reduced.
in the embodiment of the invention, the phase-to-phase difference flow is calculated according to the phase-to-phase longitudinal difference flow of the current side; the preliminary location of the single phase ground fault line segment is determined by the phase difference stream.
And 104, determining a single-phase grounding fault line section according to the phase difference flow.
In the embodiment of the invention, in order to improve accuracy, the phase-to-phase differential flow is judged according to the phase-to-phase differential flow, the phase-to-phase ground fault line segment of the phase-to-phase differential flow is verified, and after verification is successful, the phase-to-phase ground fault line segment of the phase-to-phase differential flow is determined.
According to the embodiment of the invention, when the transformer substation is detected to have a low-current ground fault, the alternating current parameters of the transformer substation are obtained; the alternating current parameters comprise a current value of a current side three phase and a current value of a current opposite side three phase; calculating split-phase longitudinal differential current according to the current value of the current side and the current value of the current side; calculating an inter-phase difference stream according to the split-phase longitudinal difference stream; and determining a single-phase grounding fault line section according to the phase difference flow. By adopting the double-end data analysis and a small-current section selection method based on second-order differential, the accuracy of line selection is greatly improved, meanwhile, the sectional positioning and tripping control of faults are realized, and the power failure range is reduced.
Referring to fig. 2, a flow chart of steps of another embodiment of a low current ground fault sectioning method of the present invention is shown, applied to a power master station connected to a plurality of substations.
In the embodiment of the invention, the power supply master station is connected with the buses of the plurality of substations by analyzing in the power supply master station, and the power supply master station can detect the electrical parameters of each substation and acquire the information of the substation.
The specific small-current ground fault section selection method can comprise the following steps:
in the embodiment of the invention, the power supply main station continuously and timely or periodically acquires three-phase voltage parameters of each transformer substation; and judging each transformer substation through the three-phase voltage parameters to determine whether abnormality exists. Wherein the three-phase voltage parameter includes a first phase voltage value, a second phase voltage value, and a third phase voltage value. I.e. the power supply master station will obtain the voltage value of each phase of the three-phase alternating current transmitted by each substation.
after the three-phase voltage parameters are obtained, monitoring three voltage values of the first phase voltage value, the second phase voltage value and the third phase voltage value, and judging whether each voltage value is between a preset non-grounding phase voltage setting value and a preset grounding phase voltage setting value. Namely, judging whether the first phase voltage value is between a preset non-grounding phase voltage setting value and a preset grounding phase voltage setting value, whether the second phase voltage value is between the preset non-grounding phase voltage setting value and the preset grounding phase voltage setting value, and whether the third phase voltage value is between the preset non-grounding phase voltage setting value and the preset grounding phase voltage setting value.
When the first phase voltage value, the second phase voltage value and the third phase voltage value are larger than the preset non-grounding phase voltage setting value and the other is smaller than the preset grounding phase voltage setting value, the method comprises the following steps: the first phase voltage value and the second phase voltage value are both greater than a preset non-ground phase voltage setting value, and the third phase voltage value is less than the preset ground phase voltage setting value. The second phase voltage value and the third phase voltage value are both greater than a preset non-ground phase voltage setting value, and the first phase voltage value is less than the preset ground phase voltage setting value. The first phase voltage value and the third phase voltage value are both greater than a preset non-ground phase voltage setting value, and the second phase voltage value is less than the preset ground phase voltage setting value. In the three cases, the substation is determined to send a low-current ground fault.
The first phase voltage value, the second phase voltage value and the third phase voltage value of the transformer substation are respectively the A phase voltage value, the B phase voltage value and the C phase voltage value of the transformer substation, wherein the A phase fault is illustrated:
wherein U is A Is the voltage value of A phase, U B Is B-phase voltage value, U C Is C-phase voltage value, U setL Setting value of ground phase voltage, U setH Is the voltage setting value of the non-grounding phase.
At this time, if the voltage value of the transformer substation is the above-mentioned column condition, the transformer substation is judged to be abnormal in voltage, and the single-phase ground fault of the transformer substation is determined.
It should be noted that, the preset non-ground phase voltage setting value and the preset ground phase voltage setting value are related to power transmitted by the transformer substation, and a person skilled in the art may determine the preset non-ground phase voltage setting value and the preset ground phase voltage setting value according to actual operation parameters of the transformer substation, which is not limited in the embodiment of the present invention.
and when the condition that the substation is detected to have a small-current ground fault is determined, acquiring alternating current parameters of the substation. Wherein the alternating current parameters include a current value of the current side three phase and a current value of the current side three phase.
in the embodiment of the invention, the split-phase longitudinal differential current between two sides of the transformer substation can be calculated according to the current value of the three phases at the side and the current value of the three phases at the opposite side.
In an alternative embodiment of the present invention, the present side three-phase current values include a present side first phase current value, a present side second phase current value, and a present side third phase current value, and the opposite side three-phase current values include an opposite side first phase current value, an opposite side second phase current value, and an opposite side third phase current value; the step of calculating the split-phase longitudinal differential flow according to the current value of the current side three phase and the current value of the opposite side three phase comprises the following steps:
step S2041, vector addition is carried out on the current value of the first phase at the current side and the current value of the first phase at the current side to obtain a first longitudinal differential stream;
in the embodiment of the invention, since the transformer substation transmits three-phase alternating current, that is, the current value of the primary side three-phase current includes the current of each phase in the three-phase alternating current, that is, the current value of the primary side first phase, the current value of the primary side second phase and the current value of the primary side third phase, correspondingly, the current value of the opposite side three-phase current also includes the current of each phase in the three-phase alternating current, that is, the current value of the opposite side first phase, the current value of the opposite side second phase and the current value of the opposite side third phase. Each corresponding alternating current may be calculated to determine the total split-phase longitudinal differential flow.
First, for the first phase electricity, vector addition may be performed on the current value of the first phase on the current side and the current value of the first phase on the current side, and the obtained value is the first phase longitudinal differential stream.
Step S2042, vector addition is carried out on the current value of the second phase at the side and the current value of the second phase at the opposite side, so as to obtain a second-phase longitudinal differential stream;
correspondingly, for the second phase electricity, vector addition can be carried out on the current value of the second phase at the side and the current value of the second phase at the opposite side, and the obtained value is the second phase longitudinal differential flow.
Step S2043, vector addition is carried out on the current value of the third phase at the current side and the current value of the third phase at the current side, so as to obtain a third longitudinal differential stream;
correspondingly, for the third phase electricity, vector addition can be carried out on the current value of the third phase on the current side and the current value of the third phase on the current side, and the obtained value is the third longitudinal differential flow.
Sub-step S2044, determining said first phase longitudinal differential stream, said second phase longitudinal differential stream, and said third phase longitudinal differential stream as said split phase longitudinal differential streams.
And determining the phase longitudinal differential flow of each phase of electricity as a phase-splitting longitudinal differential flow, namely determining the first phase longitudinal differential flow, the second phase longitudinal differential flow and the third phase longitudinal differential flow as phase-splitting longitudinal differential flows.
In summary, the combination of sub-steps S2041 to S2044 can be calculated by the following formula:
I da ＝|I a1 -I a2
I db ＝|I b1 -I b2
I dc ＝|I c1 -I c2
wherein I is da Is a first phase longitudinal differential flow, I db Is a second phase longitudinal differential flow, I dc Is a third phase longitudinal differential flow, I a1 For the current value of the first phase of the primary side, I a2 For the opposite side first phase current value, I b1 For the current value of the second phase of the primary side, I b2 For the opposite second phase current value, I c1 For the third phase current value of the primary side, I c2 Is the opposite side third phase current value.
and calculating the phase-to-phase difference flow of the current side according to the phase-to-phase longitudinal difference flow, and analyzing the road section of the current side.
In an alternative embodiment of the present invention, the step of calculating the phase difference stream from the split-phase longitudinal differential stream includes:
step S2051, performing vector subtraction on the second phase longitudinal differential stream by adopting the first phase longitudinal differential stream to obtain a first transverse differential stream;
in the embodiment of the invention, the first phase longitudinal differential flow is adopted to carry out vector subtraction on the second phase longitudinal differential flow, and the obtained value is the first transverse differential flow of the first phase electricity.
Step S2052, performing vector subtraction on the first phase longitudinal differential stream by adopting the second phase longitudinal differential stream to obtain a second transverse differential stream;
and vector subtraction is carried out on the first phase longitudinal differential flow by adopting the second phase longitudinal differential flow, and the obtained value is the second transverse differential flow of the second phase electricity.
Step S2053, performing vector subtraction on the second phase longitudinal differential stream by adopting the third phase longitudinal differential stream to obtain a third transverse differential stream;
and vector subtraction is carried out on the second-phase longitudinal differential flow by adopting the third-phase longitudinal differential flow, and the obtained value is the third transverse differential flow of the third phase power.
Sub-step S2054, determining the first lateral differential stream, the second lateral differential stream, and the third lateral differential stream as the inter-phase differential stream.
Then determining the first transverse differential stream, the second transverse differential stream and the third transverse differential stream as inter-phase differential streams; i.e. the union sub-step S2051-sub-step S2054 is available:
wherein I is Δa For the first transverse differential stream, I Δb Is a second transverse differential flow, I Δc Is the third lateral difference stream.
And determining whether the corresponding road section is a single-phase earth fault line section according to the size of the phase-to-phase differential flow.
In an alternative embodiment of the present invention, the step of determining the single phase ground fault line segment according to the phase-to-phase differential flow includes:
and in the substep S2061, when the phase-to-phase differential current is greater than a preset threshold, determining the line segment where the current value of the current side is located as the single-phase earth fault line segment.
Specifically, when any one of three lateral differential flows in the inter-phase differential flow is greater than a preset threshold, the corresponding road section can be determined to be a single-phase earth fault line section; namely, when the first transverse differential flow is larger than a preset threshold value, the A-phase road section is a single-phase ground fault line section; when the second transverse differential flow is larger than a preset threshold value, the B-phase road section is a single-phase ground fault line section; and when the third transverse differential flow is greater than a preset threshold value, the C-phase road section is a single-phase ground fault line section.
In addition, in order to avoid misjudgment and improve the identification accuracy, the inter-phase braking current of the circuit at the side can be calculated, and the determination of the road section is calculated only when the inter-phase braking current is determined to meet the normal condition, so that the judgment of the inter-phase braking current on fault diagnosis is avoided. To this end, in an alternative embodiment of the invention, the method further comprises:
and step S1, calculating inter-phase braking current according to the split-phase longitudinal differential flow.
In the embodiment of the invention, the inter-phase braking current can be calculated based on the relation between each phase in the split-phase longitudinal differential flow, namely, the inter-phase braking current can be calculated through the first phase longitudinal differential flow, the second phase longitudinal differential flow and the third phase longitudinal differential flow.
Specifically, calculating the inter-phase braking current of the first phase electricity by using the first phase longitudinal differential flow and the second phase longitudinal differential flow; calculating the interphase braking current of the second phase electricity by using the second phase longitudinal differential flow and the third phase longitudinal differential flow; and calculating the interphase braking current of the third phase electricity by using the third phase longitudinal differential flow and the first phase longitudinal differential flow. Namely:
wherein I is ra Interphase braking current, I, for the first phase of electricity rb Interphase braking current, I, being second phase electricity rc Phase-to-phase braking current for the third phase.
And S2, when the ratio of the inter-phase braking current to the inter-phase differential current is larger than a preset proportional braking coefficient, executing the step of determining the single-phase ground fault line section.
And when the ratio of the inter-phase braking current to the determined inter-phase differential current is greater than a preset proportional braking coefficient, executing the step of determining the single-phase ground fault line section. And determining the single-phase earth fault line section to improve the identification accuracy.
According to the embodiment of the invention, the three-phase voltage parameters of the transformer substation are obtained; the three-phase voltage parameter comprises a first phase voltage value, a second phase voltage value and a third phase voltage value; when the first phase voltage value, the second phase voltage value and the third phase voltage value are larger than a preset non-grounding phase voltage setting value and the other is smaller than a preset grounding phase voltage setting value, determining that the substation is detected to send a small-current grounding fault, and when the substation is detected to generate the small-current grounding fault, acquiring alternating current parameters of the substation; the alternating current parameters comprise a current value of a current side three phase and a current value of a current opposite side three phase; calculating split-phase longitudinal differential current according to the current value of the current side and the current value of the current side; calculating an inter-phase difference stream according to the split-phase longitudinal difference stream; and determining a single-phase grounding fault line section according to the phase difference flow. By adopting double-end data analysis and a small-current section selection method based on second-order differential, the accuracy of line selection is greatly improved, meanwhile, the sectional positioning and tripping control of faults are realized, and the power failure range is reduced; by utilizing wireless communication, the laying of a large number of optical fibers and cables is avoided, small-current line selection equipment is not required to be arranged, only the analysis master station is required to be arranged, and the fault diagnosis cost is reduced.
In order that those skilled in the art may better understand the embodiments of the present invention, the following description of the embodiments of the present invention is provided by way of example:
referring to fig. 3, a schematic diagram of hardware connections of an example of a low current ground fault segmentation method of the present invention is shown. The power system distribution network structure is distributed structure, and the distributed structure includes: the system comprises a plurality of distribution switch monitoring terminals and a master station system, wherein wireless communication modes are adopted between the distribution switch monitoring terminals and the master station system and between the distribution switch monitoring terminals at all sides. Wherein, the liquid crystal display device comprises a liquid crystal display device,
1) Distribution switch monitoring terminal (FTU): distributed arrangement mainly realizes collection, analysis and control strategy issuing of electric quantity; the main collected data comprise line three-phase voltage, line three-phase current and switch position states;
2) Master station system: the transformer substation is configured in the transformer substation and is responsible for comprehensively analyzing the voltage, the current and the switch position data sent by the acquisition control device, judging fault section selection and formulating a jump selection control strategy.
Based on the power distribution network structure of the power system, a small-current ground fault section selection method is described, and referring to fig. 4, a step flow chart of an example of the small-current ground fault section selection method is shown.
Step 1: during normal operation, the distributed acquisition control device is responsible for acquiring the gas quantity and the switching value data. In order to save the flow, the master station system and the distributed acquisition control device perform low-rate communication, so that the communication link is ensured to be normal.
Step 2: the master station system is connected to the bus voltage in the transformer substation, the master station system judges that the voltage is abnormal, the system is judged to have a ground fault, a fault analysis program is started, and real-time current data of the line are analyzed.
Step 3: the current on each side is calculated and analyzed. Acquiring alternating current parameters of the transformer substation; the alternating current parameters comprise a current value of a current side three phase and a current value of a current opposite side three phase; calculating split-phase longitudinal differential current according to the current value of the current side and the current value of the current side; calculating an inter-phase difference stream according to the split-phase longitudinal difference stream; and determining a single-phase grounding fault line section according to the phase difference flow.
Step 4: judging whether the branch of the single-phase earth fault line section is determined, and controlling to trip the sectionalizing switch when the single-phase earth fault line section is determined. And when the single-phase grounding fault line section is not determined, the remote master station performs manual analysis to determine the branch of the single-phase grounding fault line section.
It should be noted that, for simplicity of description, the method embodiments are shown as a series of acts, but it should be understood by those skilled in the art that the embodiments are not limited by the order of acts, as some steps may occur in other orders or concurrently in accordance with the embodiments. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred embodiments, and that the acts are not necessarily required by the embodiments of the invention.
Referring to fig. 5, there is shown a block diagram of an embodiment of a small current ground fault section selection apparatus of the present invention, applied to a power supply master station, where the power supply master station is connected to a plurality of substations, the apparatus may specifically include the following modules:
the first obtaining module 501 is configured to obtain an ac parameter of the substation when detecting that the substation has a low-current ground fault; the alternating current parameters comprise a current value of a current side three phase and a current value of a current opposite side three phase;
a first calculation module 502, configured to calculate a split-phase longitudinal differential stream according to the current value of the current side and the current value of the current side;
a second calculation module 503, for calculating an inter-phase difference stream according to the split-phase longitudinal difference stream;
a fault determination module 504 is configured to determine a single phase earth fault line segment based on the phase difference stream.
In an alternative embodiment of the invention, the apparatus further comprises:
the second acquisition module is used for acquiring three-phase voltage parameters of the transformer substation; the three-phase voltage parameter comprises a first phase voltage value, a second phase voltage value and a third phase voltage value;
and the fault detection module is used for determining that the substation sends a small-current ground fault when two of the first phase voltage value, the second phase voltage value and the third phase voltage value are larger than a preset non-ground phase voltage setting value and the other is smaller than a preset ground phase voltage setting value.
In an alternative embodiment of the invention, the apparatus further comprises:
and the third calculation module is used for calculating the inter-phase braking current according to the split-phase longitudinal differential flow.
In an alternative embodiment of the invention, the apparatus further comprises:
and the execution module is used for executing the step of determining the single-phase grounding fault line section when the ratio of the inter-phase braking current to the inter-phase differential current is larger than a preset proportional braking coefficient.
In an alternative embodiment of the present invention, the present side three-phase current values include a present side first phase current value, a present side second phase current value, and a present side third phase current value, and the opposite side three-phase current values include an opposite side first phase current value, an opposite side second phase current value, and an opposite side third phase current value; the first computing module 502 includes:
the first calculation submodule is used for carrying out vector addition on the current value of the first phase at the current side and the current value of the first phase at the opposite side to obtain a first longitudinal differential stream;
the second calculation submodule is used for carrying out vector addition on the current value of the second phase at the side and the current value of the second phase at the opposite side to obtain a second-phase longitudinal differential stream;
the third calculation submodule is used for carrying out vector addition on the current value of the third phase at the current side and the current value of the third phase at the opposite side to obtain a third longitudinal differential stream;
the split-phase longitudinal differential flow determining submodule is used for determining that the first-phase longitudinal differential flow, the second-phase longitudinal differential flow and the third-phase longitudinal differential flow are the split-phase longitudinal differential flows.
In an alternative embodiment of the present invention, the second calculating module 503 includes:
the first vector submodule is used for carrying out vector subtraction on the second phase longitudinal differential flow by adopting the first phase longitudinal differential flow to obtain a first transverse differential flow;
the second vector submodule is used for carrying out vector subtraction on the first phase longitudinal differential flow by adopting the second phase longitudinal differential flow to obtain a second transverse differential flow;
the third vector submodule is used for carrying out vector subtraction on the second-phase longitudinal differential flow by adopting the third-phase longitudinal differential flow to obtain a third transverse differential flow;
and the inter-phase difference flow determination submodule is used for determining the first transverse difference flow, the second transverse difference flow and the third transverse difference flow as the inter-phase difference flow.
In an alternative embodiment of the present invention, the fault determination module 504 includes:
and the fault determination submodule is used for determining that the line segment where the current value of the three phases on the current side is positioned is the single-phase grounding fault line segment when the phase-to-phase differential current is larger than a preset threshold value.
For the device embodiments, since they are substantially similar to the method embodiments, the description is relatively simple, and reference is made to the description of the method embodiments for relevant points.
The embodiment of the invention also provides electronic equipment, which comprises:
a processor and a storage medium storing a computer program executable by the processor, the processor executing the computer program when the electronic device is running to perform the method according to any one of the embodiments of the invention. The specific implementation manner and technical effects are partially similar to those of the method embodiment, and are not repeated here.
The storage medium may include random access memory (Random Access Memory, RAM) or may include non-volatile memory (non-volatile memory), such as at least one magnetic disk memory. Alternatively, the storage medium may be at least one storage device located remotely from the processor.
The processor may be a general-purpose processor, including a central processing unit (Central Processing Unit, CPU for short), a network processor (Network Processor, NP for short), etc.; but also digital signal processors (Digital Signal Processing, DSP for short), application specific integrated circuits (Application Specific Integrated Circuit, ASIC for short), field-programmable gate arrays (Field-Programmable Gate Array, FPGA for short) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.
Embodiments of the present invention also provide a computer readable storage medium having stored thereon a computer program which, when executed by a processor, performs a method according to any of the embodiments of the present invention. The specific implementation manner and technical effects are partially similar to those of the method embodiment, and are not repeated here.
In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described by differences from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other.
It will be apparent to those skilled in the art that embodiments of the present invention may be provided as a method, apparatus, or computer program product. Accordingly, embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the invention may take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
Embodiments of the present invention are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the embodiments of the invention.
Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or terminal device comprising the element.
The foregoing has described in detail the method, apparatus, electronic device and storage medium for small current ground fault section provided by the present invention, and specific examples have been applied to illustrate the principles and embodiments of the present invention, and the above description of the examples is only for helping to understand the method and core idea of the present invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (10)
1. A low current ground fault segment selection method, characterized by being applied to a power supply master station, the power supply master station being connected with a plurality of substations, the method comprising:
when detecting that the transformer substation has a low-current ground fault, acquiring alternating current parameters of the transformer substation; the alternating current parameters comprise a current value of a current side three phase and a current value of a current opposite side three phase;
calculating split-phase longitudinal differential current according to the current value of the current side and the current value of the current side;
calculating an inter-phase difference stream according to the split-phase longitudinal difference stream;
and determining a single-phase grounding fault line section according to the phase difference flow.
2. The method according to claim 1, wherein the method further comprises:
acquiring three-phase voltage parameters of the transformer substation; the three-phase voltage parameter comprises a first phase voltage value, a second phase voltage value and a third phase voltage value;
and when two of the first phase voltage value, the second phase voltage value and the third phase voltage value are larger than a preset non-grounding phase voltage setting value and the other is smaller than a preset grounding phase voltage setting value, determining that the substation sends a small-current grounding fault.
3. The method according to claim 1, wherein the method further comprises:
and calculating inter-phase braking current according to the split-phase longitudinal differential flow.
4. A method according to claim 3, characterized in that the method further comprises:
and when the ratio of the inter-phase braking current to the inter-phase differential current is greater than a preset proportional braking coefficient, executing the step of determining the single-phase grounding fault line section.
5. The method of claim 2, wherein the side three-phase current values comprise side first, side second and side third phase current values, and the side three-phase current values comprise side first, side second and side third phase current values; the step of calculating the split-phase longitudinal differential flow according to the current value of the current side three phase and the current value of the opposite side three phase comprises the following steps:
vector addition is carried out on the current value of the first phase at the current side and the current value of the first phase at the current side to obtain a first longitudinal differential stream;
vector addition is carried out on the current value of the second phase at the side and the current value of the second phase at the opposite side, so as to obtain a second-phase longitudinal differential stream;
vector addition is carried out on the current value of the third phase at the current side and the current value of the third phase at the current side to obtain a third longitudinal differential stream;
and determining the first phase longitudinal differential flow, the second phase longitudinal differential flow and the third phase longitudinal differential flow as the split-phase longitudinal differential flow.
6. The method of claim 5, wherein the step of calculating an inter-phase difference stream from the split-phase longitudinal differential stream comprises:
vector subtraction is carried out on the second phase longitudinal differential stream by adopting the first phase longitudinal differential stream to obtain a first transverse differential stream;
vector subtraction is carried out on the first phase longitudinal differential stream by adopting the second phase longitudinal differential stream to obtain a second transverse differential stream;
vector subtraction is carried out on the second-phase longitudinal differential stream by adopting the third-phase longitudinal differential stream to obtain a third transverse differential stream;
determining the first, second, and third lateral differential streams as the inter-phase differential streams.
7. The method of claim 1, wherein determining a single phase ground fault line segment from the phase-to-phase differential flow comprises:
and when the phase-to-phase difference flow is larger than a preset threshold value, determining the line segment where the current value of the three phases on the side is located as the single-phase grounding fault line segment.
8. A low current ground fault section selection device, characterized in that it is applied to a power supply master station, said power supply master station being connected with a plurality of substations, said device comprising:
the first acquisition module is used for acquiring alternating current parameters of the transformer substation when detecting that the transformer substation has a low-current ground fault; the alternating current parameters comprise a current value of a current side three phase and a current value of a current opposite side three phase;
the first calculation module is used for calculating split-phase longitudinal differential flow according to the current value of the current side three phase and the current value of the current opposite side three phase;
the second calculation module calculates an inter-phase difference stream according to the split-phase longitudinal difference stream;
and the fault determining module is used for determining a single-phase grounding fault line section according to the phase difference flow.
9. An electronic device comprising a processor, a memory and a computer program stored on the memory and executable on the processor, the computer program implementing the steps of the low current ground fault segmentation method according to any one of claims 1 to 7 when executed by the processor.
10. A computer readable storage medium, characterized in that the computer readable storage medium has stored thereon a computer program which, when executed by a processor, implements the steps of the low current ground fault segmentation method according to any one of claims 1 to 7.
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