CN115598465A - Intelligent line selection method, device, equipment and storage medium for low-current grounding system - Google Patents

Intelligent line selection method, device, equipment and storage medium for low-current grounding system Download PDF

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Publication number
CN115598465A
CN115598465A CN202211235578.6A CN202211235578A CN115598465A CN 115598465 A CN115598465 A CN 115598465A CN 202211235578 A CN202211235578 A CN 202211235578A CN 115598465 A CN115598465 A CN 115598465A
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China
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current
grounding system
output voltage
low
current grounding
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Inventor
李彦昌
孙雁卿
秦小芳
袁健
刘丽娟
张淑芬
李凤霞
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Taiyuan Hechuang Automatization Co ltd
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Taiyuan Hechuang Automatization Co ltd
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Priority to CN202211235578.6A priority Critical patent/CN115598465A/en
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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
    • 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
    • H02H7/262—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of switching or blocking orders
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00001—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by the display of information or by user interaction, e.g. supervisory control and data acquisition systems [SCADA] or graphical user interfaces [GUI]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00002—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by monitoring
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • H02J13/00016—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using a wired telecommunication network or a data transmission bus
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • H02J13/00022—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using wireless data transmission
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
    • H02J13/00036—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers
    • H02J13/0004—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers involved in a protection system

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Human Computer Interaction (AREA)
  • Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)

Abstract

The application relates to an intelligent line selection method, an intelligent line selection device, intelligent line selection equipment and an intelligent line selection storage medium for a low-current grounding system, which are applied to the technical field of the low-current grounding system, wherein the method comprises the following steps: acquiring output voltage of the low-current grounding system, wherein the output voltage is open triangular voltage detected by a voltage transformer on a bus in the low-current grounding system; judging whether the output voltage is greater than a preset voltage or not; if yes, acquiring zero sequence current of outgoing lines carried on each section of bus in the small current grounding system; performing state analysis on the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result; and performing tripping and/or grounding alarm based on the first analysis result. The method and the device have the effect of improving the accuracy of line selection of the line selection device.

Description

Intelligent line selection method, device, equipment and storage medium for low-current grounding system
Technical Field
The present disclosure relates to the field of low current grounding systems, and in particular, to an intelligent line selection method, apparatus, device and storage medium for a low current grounding system.
Background
The small current grounding system is a three-phase system with a neutral point not grounded or grounded through an arc suppression coil and high impedance, and is also called a neutral point indirect grounding system. When a ground fault occurs in a phase, the ground fault current tends to be much smaller than the load current because a short circuit cannot be formed, so this system is called a low current grounding system.
The small current line selection can accurately judge that the grounding loop is the basis for rapidly discharging single-phase grounding faults in time and is also the core function of the small current line selection. In the related art, one way is that an operator tries to pull each phase switch to judge the grounding point, and the other way is that the grounding point is automatically judged through a line selection device, but the algorithm of the line selection device is old and has high misjudgment rate, so that the fault point cannot be isolated at the first time during grounding, the accident is enlarged, and the production is influenced.
Disclosure of Invention
In order to improve the accuracy of line selection of a line selection device and reduce the influence of ground faults on production, the application provides an intelligent line selection method, a device, equipment and a storage medium for a low-current grounding system.
In a first aspect, the present application provides an intelligent line selection method for a low-current grounding system, which adopts the following technical scheme:
an intelligent line selection method for a low-current grounding system comprises the following steps:
acquiring output voltage of the low-current grounding system, wherein the output voltage is open triangular voltage detected by a voltage transformer on a bus in the low-current grounding system;
judging whether the output voltage is greater than a preset voltage or not;
if yes, acquiring zero sequence current of outgoing lines carried on each section of bus in the small current grounding system;
performing state analysis on the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result, wherein the state analysis comprises transient state analysis and steady state analysis;
and performing tripping and/or grounding alarm based on the first analysis result.
By adopting the technical scheme, when the output voltage is greater than the preset voltage, the small current grounding system is judged to have the single-phase grounding fault, the output voltage and the zero sequence current of the small current grounding system are subjected to transient and steady state analysis, the intelligent selection of the grounding circuit can be achieved through the transient analysis and the steady state analysis, and the accuracy of the selection of the grounding circuit can be improved through two analysis results of the transient and the steady state, so that the influence of the grounding fault on production is reduced.
Optionally, the first analysis result includes that the low-current grounding system is single-phase grounded and the low-current grounding system is bus-grounded; the state analysis of the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result comprises:
acquiring the directions of the output voltage and the zero sequence current;
judging whether the direction of the output voltage is consistent with the direction of the zero sequence current;
if the direction of the output voltage is inconsistent with the direction of the zero sequence current, judging that the corresponding outgoing lines in the small current grounding system are grounded, and recording the number of the outgoing lines which are grounded;
if the direction of the output voltage is consistent with the direction of the zero sequence current, judging that a corresponding outlet wire in a small current grounding system is not grounded, and acquiring the number of ungrounded lines based on the zero sequence current and the output voltage;
judging whether the number of the ungrounded lines is consistent with a preset number or not;
and if the number of the ungrounded lines is consistent with the preset number, judging that the small-current grounding system bus is grounded.
Optionally, before the determining whether the number of the ungrounded lines is consistent with the preset number, the method further includes:
judging whether the zero sequence current is larger than a preset current value or not;
if not, resetting the preset number.
Optionally, the performing state analysis on the small-current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result includes:
acquiring waveform images of all the output voltages of the low-current grounding system;
determining all the zero-sequence currents corresponding to the output voltage zero-crossing points based on the waveform image;
judging whether the numerical value of the zero-sequence current is not a negative value;
if so, judging that the bus in the low-current grounding system is grounded;
if not, the corresponding outlet line with the zero-sequence current in the small-current grounding system being a negative value is grounded.
Optionally, after performing state analysis on the small-current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result, the method further includes:
judging whether the output voltage has resonance or not;
and if so, eliminating the harmonic of the output voltage.
Optionally, after performing state analysis on the small-current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result, the method further includes:
acquiring ground fault information of the low-current grounding system based on the first analysis result;
generating a ground fault table based on the ground fault information;
performing fault analysis on the low-current grounding system based on the grounding fault table to obtain a second analysis result;
and monitoring the low-current grounding system based on the second analysis result.
Optionally, before the performing the trip and/or ground fault alarm based on the first analysis result, the method further includes:
determining a start time of a ground fault of the low-current grounding system based on the first analysis result;
timing based on the starting time to obtain timing time;
judging whether the timing time is equal to a preset time or not;
and if so, controlling the grounding switch to act.
In a second aspect, the present application provides an intelligent line selection device for a low-current grounding system, which adopts the following technical scheme:
an intelligent line selection device of a low-current grounding system comprises:
the acquisition module is used for acquiring the output voltage of the low-current grounding system;
the judging module is used for judging whether the output voltage is greater than a preset voltage or not; if yes, acquiring a zero sequence current of the small current grounding system;
the analysis module is used for carrying out state analysis on the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result;
and the control module is used for carrying out tripping and/or grounding alarm based on the first analysis result.
By adopting the technical scheme, when the output voltage is greater than the preset voltage, the small current grounding system is judged to have the single-phase grounding fault, the output voltage and the zero sequence current of the small current grounding system are subjected to transient and steady state analysis, the intelligent selection of the grounding circuit can be achieved through the transient analysis and the steady state analysis, and the accuracy of the selection of the grounding circuit can be improved through two analysis results of the transient and the steady state, so that the influence of the grounding fault on production is reduced.
In a third aspect, the present application provides an electronic device, which adopts the following technical solutions:
an electronic device comprising a processor, the processor coupled with a memory;
the processor is configured to execute the computer program stored in the memory to cause the electronic device to perform the method for intelligent line selection of the low-current grounding system according to any one of the first aspect.
In a fourth aspect, the present application provides a computer-readable storage medium, which adopts the following technical solutions:
a computer readable storage medium storing a computer program that can be loaded by a processor and executed to perform the intelligent line selection method of the low current grounding system of any one of the first aspect.
Drawings
Fig. 1 is a schematic flowchart of an intelligent line selection method for a low-current grounding system according to an embodiment of the present application.
Fig. 2 is a diagram of a phase-a ground field current distribution.
Fig. 3 is a block diagram of a structure of an intelligent line selection device of a low-current grounding system according to an embodiment of the present application.
Fig. 4 is a block diagram of an electronic device according to an embodiment of the present disclosure.
Detailed Description
The present application is described in further detail below with reference to the accompanying drawings.
The embodiment of the application provides an intelligent line selection method for a low-current grounding system, which can be executed by electronic equipment, wherein the electronic equipment can be a server or terminal equipment, the server can be an independent physical server, a server cluster or a distributed system formed by a virtual machine or a plurality of physical servers, and a cloud server for providing cloud computing service. The terminal device may be, but is not limited to, a smart phone, a tablet computer, a desktop computer, etc.
Fig. 1 is a schematic flow chart of an intelligent line selection method for a low-current grounding system according to an embodiment of the present application.
As shown in fig. 1, the main flow of the method is described as follows (steps S101 to S105):
step S101, obtaining output voltage of the low-current grounding system, wherein the output voltage is open triangular voltage detected by a voltage transformer on a bus in the low-current grounding system.
In this embodiment, the output voltage of the low-current grounding system can be obtained through the voltage transformer, the voltage transformer adopts an open-delta connection method, and whether the grounding condition occurs in the low-current grounding system is judged by detecting the open-delta voltage of the voltage transformer.
When the small-current grounding system has no single-phase grounding fault, the output voltage of the opening triangle of the voltage transformer is in a first stable state, when the small-current grounding system has the single-phase grounding fault, the output voltage of the opening triangle of the voltage transformer is changed for a short time, and after the short-time change, the small-current grounding system enters a second stable state.
Step S102, judging whether the output voltage is greater than a preset voltage; if yes, the process proceeds to step S103, otherwise, step S101 is repeated.
In this embodiment, the preset voltage may be different for different operating environments, and is generally set to 30V, but in some old power plants or substations, the preset voltage may be set to 15V. In this embodiment, the predetermined voltage is 30V.
Further, when the detected output voltage is greater than 30V, it can be preliminarily determined that the small-current grounding system has a ground fault, and it is necessary to detect each line in the small-current grounding system, so as to determine which specific line has a ground fault or a bus has a ground fault, so as to respond in time and make a corresponding action.
When the detected output voltage is less than or equal to 30V, the low-current grounding system can be detected in real time by acquiring the output voltage in real time, so that the damage to equipment caused by the ground fault of the low-current grounding system is reduced.
And step S103, acquiring zero sequence current of the outgoing lines carried by each section of bus in the small current grounding system.
In a small current grounding system, each phase voltage has a capacitance to ground relative to the ground, if a certain phase has a ground fault, the capacitance to ground with the ground fault is short-circuited, but the other two phases have current relative to the ground capacitance, the neutral point voltage to ground rises to be a phase voltage, the voltage to ground of the non-fault phase rises to be a line voltage, and the symmetry of the phase voltage and the capacitor current is broken, so that the neutral point has zero sequence current.
In the small current grounding system, the zero sequence current can be detected through the current transformer, and then the zero sequence current is displayed.
And step S104, performing state analysis on the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result.
In this embodiment, the first analysis result includes that the low-current grounding system is single-phase grounded and the low-current grounding system is bus-grounded; performing state analysis on the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result, wherein the first analysis result comprises the following steps: acquiring directions of output voltage and zero sequence current; judging whether the direction of the output voltage is consistent with the direction of the zero sequence current; if the direction of the output voltage is inconsistent with the direction of the zero sequence current, the outgoing lines in the small current grounding system are grounded, and the number of the outgoing lines which are grounded is recorded; if the direction of the output voltage is consistent with the direction of the zero sequence current, judging that the corresponding outgoing line in the small current grounding system is not grounded, and acquiring the number of ungrounded lines based on the zero sequence current and the output voltage; judging whether the number of the ungrounded lines is consistent with a preset number or not; and if the number of the ungrounded lines is consistent with the preset number, judging that the small-current grounding system bus is grounded.
Specifically, the preset number is the total number of lines in the small-current grounding system, when the small-current grounding system has a ground fault, the symmetry of phase voltage and capacitance current of the small-current grounding system is broken, the grounding capacitor is short-circuited at the moment, zero-sequence voltage and zero-sequence current are generated, and the output voltage at the moment is zero-sequence voltage.
The waveforms of the zero-sequence voltage and the zero-sequence current are obtained, and the phases of the zero-sequence voltage and the zero-sequence current can be judged according to the waveforms, so that the directions of the zero-sequence voltage and the zero-sequence current are determined.
Referring to fig. 2, if a phase a has a ground fault, a zero sequence voltage and a zero sequence current occur because the symmetry of the phase voltage and the capacitance current is broken, and at this time:
the voltage of phase a is: UA1=0;
the magnitude of the zero sequence voltage is as follows: 3U0= UB1+ UC1;
UB1 is B voltage to ground, UC1 is C voltage to ground.
In the non-faulty line 1,
the current of phase A is: IA1=0;
the zero-sequence current is: 3I0= IB1+ IC1;
where IB1 is the B-phase current of the non-faulty line 1, and IC1 is the C-phase current of the non-faulty line 1.
In the faulty line 2:
the current of phase A is: IA2= - (IB 2+ IB1+ IC2+ IC 1);
the zero-sequence current is: 3I0= IA2+ IB2+ IC2= - (IB 1+ IB 2);
here, IA2 is the a-phase current of the faulty line 2, IB2 is the B-phase current of the faulty line 2, and IC2 is the C-phase current of the faulty line 2.
When the phase A in the fault line 2 has an earth fault, the non-fault line 1 has no fault, and the phase of the zero-sequence current in the non-fault line 1 is ahead of the zero-sequence voltage by 90 degrees, the phase of the zero-sequence current in the fault line 2 is behind the zero-sequence voltage by 90 degrees, and the phase of the zero-sequence current in the non-fault line 1 is 180 degrees different from that of the non-fault line 1, so that the earth line can be selected.
In this embodiment, since each bus has a plurality of outgoing lines to drive the electric device, it is necessary to further determine whether the bus has a ground fault, that is, the output voltages of the plurality of outgoing lines led out from each outgoing line are needed, and the phase of the output voltage and the output current of each outgoing line are determined. If the number of the ungrounded lines is the same as the total number of the lines, the bus can be judged to have the ground fault; otherwise, a fault occurs for a certain outlet.
It is worth to be noted that the transient state data of the zero sequence voltage and the zero sequence current collected by the voltage transformer and the current transformer need to be subjected to filtering row judgment and analyzed for multiple times, and then the accuracy of the grounding circuit is improved.
Further, because each outgoing line may have an empty load condition, when determining the number of the main lines, it is necessary to determine whether the zero-sequence current on each outgoing line is greater than a preset current fixed value, and when the detected zero-sequence current is less than a preset current value, and when setting the preset number, the outgoing line with the zero-sequence current less than the preset current value is in an empty load state, and the probability of occurrence of a ground fault is low, so the number of the outgoing lines with the zero-sequence current less than the preset current value is not counted by default, so as to increase the accuracy of selecting the faulty outgoing line. Further, performing state analysis on the small-current grounding system based on the output voltage and the zero-sequence current to obtain a first analysis result, further comprising: acquiring waveform images of all output voltages of the low-current grounding system; determining all zero-sequence currents corresponding to the zero-crossing points of the output voltage based on the waveform image; judging whether the numerical value of the zero sequence current is not a negative value; if so, judging that the bus in the low-current grounding system is grounded; if not, the corresponding outlet line with the zero sequence current in the small current grounding system being a negative value is grounded.
In this embodiment, after the ground fault occurs in the low-current grounding system, the output voltage and the current change briefly and then enter a new steady state, so that after the output voltage is greater than the preset voltage, not only the transient analysis but also the steady state analysis need to be completed, and the accuracy of selecting the fault outgoing line is improved by combining the transient analysis and the steady state analysis.
Specifically, when the output voltage is greater than the preset voltage, waveform images of all output voltages of the small-current grounding system are obtained, then a current value of the zero-sequence current is obtained according to the waveform images, and meanwhile, whether the corresponding zero-sequence current value is a negative value or not is judged according to the waveform images when the output voltage crosses the zero point, if the corresponding zero-sequence current is the negative value, the outgoing line corresponding to the zero-sequence current has a grounding fault, and when all the zero-sequence current values are not the negative value, the bus is judged to have the grounding fault, otherwise, the outgoing line has the grounding fault.
In order to improve the accuracy of selecting the grounding circuit, after performing state analysis on the low-current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result, the method further includes: judging whether the output voltage has resonance or not; and if so, performing harmonic elimination output on the output voltage.
When an electric power system is powered on, due to three-phase different-period or instantaneous ground faults, harmonic current can be generated in the voltage transformer, an iron core inside the voltage transformer is saturated, and the waveform of a secondary side of the voltage transformer is changed, so that ferromagnetic resonance is formed.
When overvoltage or ferromagnetic resonance occurs, whether the small current grounding system resonates or not needs to be judged, when the small current grounding system does not resonate, the selected grounding line is output, and when the small current grounding system resonates, the resonance needs to be eliminated, and the grounding line is reselected.
Specifically, in the process of operating the low-current grounding system, grounding misjudgment caused by transient grounding or ferromagnetic resonance may occur, so that whether resonance exists or not needs to be judged for the output voltage, and when the resonance exists in the output voltage, the resonance elimination operation needs to be performed on the obtained output voltage, so that the influence of the resonance on the process of selecting a grounding circuit is reduced, and the selected grounding circuit is more accurate.
In this embodiment, after performing state analysis on the small-current grounding system based on the output voltage and the zero-sequence current to obtain a first analysis result, the method further includes: acquiring ground fault information of the low-current grounding system based on the first analysis result; generating a ground fault table based on the ground fault information; performing fault analysis on the low-current grounding system based on the grounding fault table to obtain a second analysis result; and monitoring the low-current grounding system based on the second analysis result.
Specifically, after the ground line is determined, the ground fault information is stored, a first ground fault table is generated according to the ground fault information, the ground fault information is supplemented to the first ground fault table, the first ground fault table is compared with data in a database, the reason of the ground fault of the fault line is analyzed, whether the ground fault is caused by the same reason or not is judged, if the ground fault is caused by the same reason, the reason and the processing method which cause the ground fault can be input into the database, so that the subsequent ground fault caused by the same reason can be quickly processed and the ground line can be selected, and the method is more convenient and quick.
The grounding fault information comprises grounding initial time, a fault line number and fault accumulated time; the data of the database comprises ground fault information of ground faults generated for various reasons; the second analysis result includes a fault cause causing the ground fault.
And step S105, performing tripping and/or grounding alarm based on the first analysis result.
Specifically, after the first analysis result is obtained, if the outgoing line has a ground fault, the ground switch on the outgoing line is controlled to operate to protect the electrical equipment on the outgoing line, and if the bus has a ground fault, the ground switch on the bus needs to be controlled to operate to protect all the electrical equipment on the outgoing line.
Further, before performing a trip and/or ground alarm based on the first analysis result, the method further comprises: determining a starting moment of a ground fault of the low-current grounding system based on the first analysis result; timing based on the starting time to obtain timing time; judging whether the timing time is equal to the preset time or not; and if so, carrying out tripping and/or grounding alarm.
Specifically, after the first analysis result is obtained, the time for obtaining the first analysis result is taken as the starting time, the time is counted from the starting time, the timing time is obtained, and the time delay of the grounding switch action is completed through the timing time, so that the possibility of action caused by instantaneous grounding or ferromagnetic resonance is reduced, the misjudgment is reduced, and the accuracy of selecting the grounding circuit is further improved.
Fig. 2 is a block diagram of an intelligent line selection apparatus 200 of a low-current grounding system according to an embodiment of the present disclosure.
As shown in fig. 3, the intelligent line selection device 200 for the low-current grounding system mainly includes:
the first obtaining module 201 is configured to obtain an output voltage of the low-current grounding system, where the output voltage is an open delta voltage detected by a voltage transformer on a bus in the low-current grounding system;
the judging module 202 is used for judging whether the output voltage is greater than a preset voltage; if yes, acquiring zero sequence current of outgoing lines carried on each section of bus in the small current grounding system;
the analysis module 203 is configured to perform state analysis on the small-current grounding system based on the output voltage and the zero-sequence current to obtain a first analysis result, where the state analysis includes transient analysis and steady-state analysis;
and the control module 204 is used for carrying out tripping and/or grounding alarm based on the first analysis result.
As an optional implementation manner of this embodiment, the determining module 202 is further specifically configured to determine that the first analysis result includes that the low-current grounding system generates single-phase grounding and low-current grounding system bus grounding; performing state analysis on the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result, wherein the first analysis result comprises the following steps: acquiring the directions of output voltage and zero sequence current; judging whether the direction of the output voltage is consistent with the direction of the zero sequence current; if the direction of the output voltage is inconsistent with the direction of the zero sequence current, judging that the corresponding outgoing lines in the small current grounding system are grounded, and recording the number of the outgoing lines which are grounded; if the direction of the output voltage is consistent with the direction of the zero sequence current, judging that the corresponding outgoing line in the small current grounding system is not grounded, and acquiring the number of ungrounded lines based on the zero sequence current and the output voltage; judging whether the number of the ungrounded lines is consistent with a preset number or not; and if the number of the ungrounded lines is consistent with the preset number, judging that the small-current grounding system bus is grounded.
As an optional implementation manner of this embodiment, the determining module 202 is further specifically configured to, before determining whether the number of the ungrounded lines is consistent with the preset number, further include: judging whether the zero sequence current is larger than a preset current value or not; if not, resetting the preset number.
As an optional implementation manner of this embodiment, the determining module 202 is further specifically configured to perform state analysis on the small-current grounding system based on the output voltage and the zero-sequence current, and obtain a first analysis result, where the obtaining the first analysis result includes: acquiring waveform images of all output voltages of the low-current grounding system; determining all zero-sequence currents corresponding to the zero-crossing points of the output voltage based on the waveform image; judging whether the numerical value of the zero-sequence current is not a negative value; if yes, judging that a female outlet in the low-current grounding system is grounded; if not, the corresponding outlet line with the zero-sequence current being a negative value in the small-current grounding system is grounded.
As an optional implementation manner of this embodiment, the determining module 202 is further specifically configured to, after performing state analysis on the low-current grounding system based on the output voltage and the zero-sequence current to obtain a first analysis result, the method further includes: judging whether the output voltage has resonance or not; and if so, performing harmonic elimination output on the output voltage.
As an optional implementation manner of this embodiment, the determining module 202 is further specifically configured to, after performing state analysis on the low-current grounding system based on the output voltage and the zero-sequence current to obtain a first analysis result, the method further includes: acquiring ground fault information of the low-current grounding system based on the first analysis result; generating a ground fault table based on the ground fault information; carrying out fault analysis on the low-current grounding system based on the grounding fault table to obtain a second analysis result; and monitoring the low-current grounding system based on the second analysis result.
As an optional implementation manner of this embodiment, the control module 204 is further specifically configured to, before performing the trip and/or ground alarm based on the first analysis result, further include: determining a starting moment of a ground fault of the low-current grounding system based on the first analysis result; timing based on the starting time to obtain timing time; judging whether the timing time is equal to the preset time or not; and if so, carrying out tripping and/or grounding alarm.
In one example, the modules in any of the above apparatus may be one or more integrated circuits configured to implement the above method, for example: one or more Application Specific Integrated Circuits (ASICs), or one or more Digital Signal Processors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs), or a combination of at least two of these integrated circuit forms.
For another example, when a module in a device may be implemented in the form of a processing element scheduler, the processing element may be a general-purpose processor, such as a Central Processing Unit (CPU) or other processor capable of invoking programs. As another example, these modules may be integrated together, implemented in the form of a system-on-a-chip (SOC).
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described apparatuses and modules may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
Fig. 4 is a block diagram of an electronic device 300 according to an embodiment of the present disclosure.
As shown in FIG. 4, electronic device 300 includes a processor 301 and memory 302, and may further include an information input/information output (I/O) interface 303, one or more of a communications component 304, and a communications bus 305.
The processor 301 is configured to control the overall operation of the electronic device 300, so as to complete all or part of the steps of the intelligent line selection method for the low-current grounding system; the memory 302 is used to store various types of data to support operation at the electronic device 300, such data may include, for example, instructions for any application or method operating on the electronic device 300, as well as application-related data. The Memory 302 may be implemented by any type of volatile or non-volatile Memory device or combination thereof, such as one or more of Static Random Access Memory (SRAM), electrically Erasable Programmable Read-Only Memory (EEPROM), erasable Programmable Read-Only Memory (EPROM), programmable Read-Only Memory (PROM), read-Only Memory (ROM), magnetic Memory, flash Memory, magnetic or optical disk.
The I/O interface 303 provides an interface between the processor 301 and other interface modules, such as a keyboard, mouse, buttons, etc. These buttons may be virtual buttons or physical buttons. The communication component 304 is used for wired or wireless communication between the electronic device 300 and other devices. Wireless Communication, such as Wi-Fi, bluetooth, near Field Communication (NFC), 2G, 3G, or 4G, or a combination of one or more of them, so that the corresponding Communication component 304 may include: wi-Fi part, bluetooth part, NFC part.
The electronic Device 300 may be implemented by one or more Application Specific Integrated Circuits (ASICs), digital Signal Processors (DSPs), digital Signal Processing Devices (DSPDs), programmable Logic Devices (PLDs), field Programmable Gate Arrays (FPGAs), controllers, microcontrollers, microprocessors or other electronic components, and is configured to perform the intelligent line selection method of the low current grounding system according to the above embodiments.
The communication bus 305 may include a path that carries information between the aforementioned components. The communication bus 305 may be a PCI (Peripheral Component Interconnect) bus, an EISA (Extended Industry Standard Architecture) bus, or the like. The communication bus 305 may be divided into an address bus, a data bus, a control bus, and the like.
The electronic device 300 may include, but is not limited to, a mobile terminal such as a mobile phone, a notebook computer, a digital broadcast receiver, a PDA (personal digital assistant), a PAD (tablet), a PMP (portable multimedia player), a vehicle-mounted terminal (e.g., a car navigation terminal), etc., and a stationary terminal such as a digital TV, a desktop computer, etc., and may also be a server, etc.
The application also provides a computer readable storage medium, on which a computer program is stored, and the computer program, when executed by a processor, implements the steps of the intelligent line selection method for the low-current grounding system.
The computer-readable storage medium may include: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus 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 apparatus.
The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by those skilled in the art that the scope of the application referred to in the present application is not limited to the embodiments in which the above-mentioned features are combined in particular, and also encompasses other embodiments in which the above-mentioned features or their equivalents are combined arbitrarily without departing from the concept of the application. For example, the above features may be replaced with (but not limited to) features having similar functions as those described in this application.

Claims (10)

1. An intelligent line selection method for a low-current grounding system is characterized by comprising the following steps:
acquiring output voltage of the low-current grounding system, wherein the output voltage is open triangular voltage detected by a voltage transformer on a bus in the low-current grounding system;
judging whether the output voltage is greater than a preset voltage or not;
if yes, acquiring zero sequence current of outgoing lines carried on each section of bus in the small current grounding system;
performing state analysis on the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result, wherein the state analysis comprises transient state analysis and steady state analysis;
and performing tripping and/or grounding alarm based on the first analysis result.
2. The method of claim 1, wherein the first analysis result comprises that the low current grounding system is single phase grounded and the low current grounding system is bus grounded; the state analysis of the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result comprises:
acquiring the directions of the output voltage and the zero sequence current;
judging whether the direction of the output voltage is consistent with the direction of the zero sequence current;
if the direction of the output voltage is inconsistent with the direction of the zero sequence current, judging that the corresponding outgoing lines in the small current grounding system are grounded, and recording the number of the outgoing lines which are grounded;
if the direction of the output voltage is consistent with the direction of the zero sequence current, judging that a corresponding outlet wire in a small current grounding system is not grounded, and acquiring the number of ungrounded lines based on the zero sequence current and the output voltage;
judging whether the number of the ungrounded lines is consistent with a preset number or not;
and if the number of the ungrounded lines is consistent with the preset number, judging that the small-current grounding system bus is grounded.
3. The method of claim 2, wherein before the determining whether the number of ungrounded lines is consistent with the preset number, the method further comprises:
judging whether the zero sequence current is larger than a preset current value or not;
if not, resetting the preset number.
4. The method according to claim 1 or 2, wherein the analyzing the state of the low-current grounding system based on the output voltage and the zero sequence current, and obtaining a first analysis result comprises:
acquiring waveform images of all the output voltages of the low-current grounding system;
determining all the zero-sequence currents corresponding to the output voltage zero-crossing points based on the waveform image;
judging whether the numerical value of the zero-sequence current is not a negative value;
if so, judging that the bus in the low-current grounding system is grounded;
if not, the corresponding outlet line with the zero-sequence current in the small-current grounding system being a negative value is grounded.
5. The method of claim 4, wherein after the analyzing the state of the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result, the method further comprises:
judging whether the output voltage has resonance or not;
and if so, eliminating the harmonic of the output voltage.
6. The method of claim 1, wherein after the analyzing the state of the small-current grounding system based on the output voltage and the zero-sequence current to obtain a first analysis result, the method further comprises:
acquiring ground fault information of the low-current grounding system based on the first analysis result;
generating a ground fault table based on the ground fault information;
performing fault analysis on the low-current grounding system based on the ground fault table, obtaining a second analysis result;
and monitoring the low-current grounding system based on the second analysis result.
7. The method of claim 1, wherein prior to said conducting a trip and/or ground alarm based on said first analysis, said method further comprises:
determining a start time of a ground fault of the low-current grounding system based on the first analysis result;
timing based on the starting time to obtain timing time;
judging whether the timing time is equal to a preset time or not;
and if so, controlling the grounding switch to act.
8. The utility model provides a undercurrent grounding system intelligence route selection device which characterized in that includes:
the acquisition module is used for acquiring the output voltage of the low-current grounding system;
the judging module is used for judging whether the output voltage is greater than a preset voltage or not; if yes, acquiring a zero sequence current of the small current grounding system;
the analysis module is used for carrying out state analysis on the small current grounding system based on the output voltage and the zero sequence current to obtain a first analysis result;
and the control module is used for carrying out tripping and/or grounding alarm based on the first analysis result.
9. An electronic device comprising a processor, the processor coupled with a memory;
the processor is configured to execute a computer program stored in the memory to cause the electronic device to perform the method of any of claims 1 to 7.
10. A computer-readable storage medium comprising a computer program or instructions which, when run on a computer, cause the computer to carry out the method of any one of claims 1 to 7.
CN202211235578.6A 2022-10-10 2022-10-10 Intelligent line selection method, device, equipment and storage medium for low-current grounding system Pending CN115598465A (en)

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