CN112398104B - Comprehensive monitoring protection system for insulation, arc light and line selection of power distribution network - Google Patents
Comprehensive monitoring protection system for insulation, arc light and line selection of power distribution network Download PDFInfo
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- CN112398104B CN112398104B CN202011379048.XA CN202011379048A CN112398104B CN 112398104 B CN112398104 B CN 112398104B CN 202011379048 A CN202011379048 A CN 202011379048A CN 112398104 B CN112398104 B CN 112398104B
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- 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
- H02H7/28—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 for meshed systems
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/58—Testing of lines, cables or conductors
- G01R31/60—Identification of wires in a multicore cable
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
Abstract
The utility model provides a distribution network insulation, arc light, selected line comprehensive monitoring protection system, the system includes pulse voltage acquisition device, wide band current acquisition device and power frequency voltage acquisition device, and connects pulse voltage acquisition device wide band current acquisition device with power frequency voltage acquisition device's comprehensive controller. The comprehensive controller is configured to monitor the insulation faults of the switch cabinet and determine the types of the insulation faults according to the acquired operation parameters of the switch cabinet; the integrated controller can also monitor the isolated light fault of the switch cabinet and realize line selection and phase selection of the ground fault of the power distribution network. The method combines the functions of insulation fault, light-isolated protection and line selection detection, and has comprehensive functions and extremely high judgment accuracy.
Description
Technical Field
The application relates to the technical field of monitoring protection of power systems, in particular to a comprehensive monitoring protection system for insulation, arc light and line selection of a power distribution network.
Background
On the one hand, the distribution network electrical equipment is an important infrastructure for guaranteeing reliable power supply, operation and maintenance of other auxiliary equipment such as a switch cabinet/a ring main unit switch are mainly detected by periodically carrying out insulation tests or a post-fault maintenance and replacement mode is adopted, power failure is required to be detected by periodically detecting equipment or the post-fault maintenance and replacement mode causes sudden power failure, the power supply reliability is affected, and the quantity of the distribution equipment is numerous, such as huge workload of the periodic maintenance mode. On the other hand, single-phase earth faults of the distribution network frequently occupy more than 80% of the total number of faults, the earth faults are arc faults, the arc faults can occur on buses and lines, the current technology on the occurrence buses adopts the arc protection technology of detection light, the occurrence of line selection protection and tripping isolation faults on the lines, the high-resistance earth in an overhead network occupies the vast majority, and the current comprehensive line selection accuracy is lower than 90% because the fault characteristics of the high-resistance earth faults are not obvious.
However, the current insulation monitoring, arc light protection and line selection protection technologies of the power distribution network are technologies of three different technical ideas, and the three different technical means correspond to three sets of equipment, so that the problems of inconvenient management, high cost, complex implementation, low detection sensitivity, small coverage and the like of the three sets of equipment exist in application.
In order to solve the problems in the prior art, the application provides a comprehensive monitoring and protecting system for insulation, arc light and line selection of a power distribution network.
Disclosure of Invention
The utility model provides a distribution network insulation, arc light, route selection comprehensive monitoring protection system to solve when carrying out insulation monitoring, arc light protection and trouble route selection to the distribution network, use three sets of equipment, the management is inconvenient, three sets of equipment are with high costs, implement complicacy, detect the low and cover face scheduling problem of sensitivity.
The application provides a distribution network insulation, arc light, route selection comprehensive monitoring protection system, the system includes: the device comprises a pulse voltage acquisition device, a broadband current acquisition device and a power frequency voltage acquisition device, and a comprehensive controller connected with the pulse voltage acquisition device, the broadband current acquisition device and the power frequency voltage acquisition device;
the pulse voltage acquisition device is arranged on the outlet side of each monitored switch cabinet, and is used for acquiring a high-frequency pulse voltage signal of the switch cabinet and sending the high-frequency pulse voltage signal to the comprehensive controller;
the broadband current acquisition device is arranged on the outlet side of each monitored switch cabinet, and is used for acquiring broadband zero sequence current signals of the switch cabinet and sending the broadband zero sequence current signals to the comprehensive controller;
the power frequency voltage acquisition device is connected with the switch cabinet bus and is used for acquiring a power frequency voltage signal of the switch cabinet and sending the power frequency voltage signal to the comprehensive controller;
the integrated controller is configured to perform the steps of:
determining a high-frequency pulse voltage amplitude and a high-frequency pulse voltage phase according to the high-frequency pulse voltage signal;
filtering and decomposing the broadband zero sequence current signal to determine a power frequency zero sequence current signal and a high frequency pulse current signal contained in the broadband zero sequence current signal;
determining whether an insulation fault exists in the switch cabinet according to the high-frequency pulse voltage amplitude and the power frequency zero sequence current signal, or according to the high-frequency pulse voltage amplitude, the high-frequency pulse current signal and the power frequency zero sequence current signal, or according to the high-frequency pulse voltage amplitude, the high-frequency pulse voltage phase and the power frequency voltage signal; if yes, further judging the type of the insulation fault;
determining whether arc faults exist on bus equipment according to the high-frequency pulse voltage amplitude and the high-frequency pulse current signal; if yes, an arc light protection early warning is sent out, and arc light protection measures are taken;
determining whether a line has a ground fault according to the high-frequency pulse voltage amplitude and the high-frequency pulse current signal; if yes, the earth fault early warning is sent out, and earth fault protection measures are taken.
Optionally, determining whether an insulation fault exists in the switch cabinet according to the high-frequency pulse voltage amplitude and the power frequency zero sequence current signal, or according to the high-frequency pulse voltage amplitude, the high-frequency pulse current signal and the power frequency zero sequence current signal, or according to the high-frequency pulse voltage amplitude, the high-frequency pulse voltage phase and the power frequency voltage signal; if yes, further judging the type of the insulation fault, including:
obtaining the maximum high-frequency pulse voltage amplitude;
when the amplitude of the maximum high-frequency pulse voltage is greater than or equal to a preset starting fixed value for more than two times continuously, if so, judging that the switch cabinet has an insulation fault; further judging whether the power frequency zero sequence current signal has zero rest characteristics, if so, judging that the type of the insulation fault is a single-phase grounding fault; if not, judging the type of the insulation fault to be tip discharge or creeping discharge;
or when the maximum high-frequency pulse voltage amplitude is greater than or equal to the starting fixed value for more than two times continuously, if yes, judging that the switch cabinet has insulation faults; further judging that the high-frequency pulse current signal has a phase characteristic according to the power frequency zero sequence current signal, and if so, judging that the insulation fault type is single-phase grounding fault; if not, judging the type of the insulation fault to be tip discharge or creeping discharge;
or when the amplitude of the maximum high-frequency pulse voltage is more than twice continuously and is greater than a preset ground fault setting value, if so, judging that the switch cabinet has an insulation fault; further judging whether the phase of the high-frequency pulse voltage has a phase characteristic according to the power frequency voltage signal, if so, judging that the type of the insulation fault is a single-phase grounding fault; if not, judging the type of the insulation fault as tip discharge or creeping discharge.
Optionally, the start-up setting value and the ground fault setting value are determined by:
in the system fault-free state, determining the noise pulse voltage amplitude according to the high-frequency pulse voltage amplitude of each phase of each line;
determining the starting constant value according to the noise pulse voltage amplitude;
and determining the ground fault setting value according to the starting setting value.
Optionally, the determining whether the arc fault exists on the bus device according to the high-frequency pulse voltage amplitude, the high-frequency pulse current signal and the power frequency voltage signal includes:
and when the maximum high-frequency pulse voltage amplitude is greater than or equal to the starting fixed value for more than two times continuously and all the high-frequency pulse current phases are in the same phase, determining that arc faults occur on the bus equipment.
Optionally, the determining whether the line has a ground fault according to the high-frequency pulse voltage amplitude, the high-frequency pulse current signal and the power frequency voltage signal includes:
and when the maximum high-frequency pulse voltage amplitude is more than twice continuously and is more than or equal to the starting fixed value, if the phase of the high-frequency pulse current of one line is opposite to that of other lines, judging that the line has a ground fault.
Optionally, the determining that the high-frequency pulse current signal has a phase characteristic according to the power frequency zero sequence current signal includes:
acquiring phases corresponding to the maximum values of the high-frequency pulse currents in two adjacent periods;
judging whether the phase corresponding to the maximum value of the high-frequency pulse current in two adjacent periods occurs when the power frequency zero sequence current passes through zero or not, wherein the phases are respectively positioned at preset current positions, the preset current positions comprise a first position and a second position which are synchronous with the phase relative to the power frequency zero sequence current, and the first position and the second position are used for synchronizing the phases of the power frequency zero sequence current, wherein: the first position is
The second position is
Optionally, the determining whether the high-frequency pulse voltage phase has a phase characteristic according to the power frequency voltage signal includes:
acquiring phases corresponding to the maximum values of the high-frequency pulse voltages in two adjacent periods;
judging the height in two adjacent periodsWhether the phase corresponding to the maximum value of the frequency pulse voltage is located at a preset voltage position or not respectively, wherein the preset voltage position comprises a third position and a fourth position which are synchronous with the phase relative to the power frequency voltage, and the third position and the fourth position are formed by: the third position is
The fourth position is +.>
Optionally, the pulse voltage acquisition device is a three-phase sensor, and each phase includes a coupling capacitance sensor and a detection impedance.
Optionally, the broadband current acquisition device is an electromagnetic zero sequence current transformer, a hall current sensor or a rogowski coil.
Optionally, the power frequency voltage acquisition device is an electromagnetic voltage transformer, a photoelectric voltage transformer or a capacitive voltage transformer.
The utility model provides a distribution network insulation, arc light, selected line comprehensive monitoring protection system, the system includes pulse voltage acquisition device, wide band current acquisition device and power frequency voltage acquisition device, and connects pulse voltage acquisition device wide band current acquisition device with power frequency voltage acquisition device's comprehensive controller. The comprehensive controller is configured to monitor the insulation faults of the switch cabinet and determine the types of the insulation faults according to the acquired operation parameters of the switch cabinet; the integrated controller can also monitor the isolated light fault of the switch cabinet and realize line selection and phase selection of the ground fault of the power distribution network. The power distribution equipment insulation fault monitoring device combines the insulation fault, the islanding protection and the line selection detection functions, has comprehensive functions and extremely high judgment accuracy, and has the advantages that (1) the device can monitor the power distribution equipment insulation fault, including point discharge, creeping discharge and grounding fault, especially high-resistance grounding fault; (2) means for monitoring arc protection of the power distribution device; (3) The device can realize line selection and phase selection of the ground fault of the power distribution network. The invention integrates the functions of insulation fault, arc protection and line selection detection. Compared with the prior art and equipment, the technical method and the device have the advantages of comprehensive functions, quick response, accurate judgment, high detection sensitivity and the like.
Drawings
In order to more clearly illustrate the technical solutions of the present application, the drawings that are needed in the embodiments will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.
Fig. 1 is a schematic structural diagram of a comprehensive monitoring protection system for insulation, arc light and line selection of a power distribution network according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of a pulse voltage acquisition device according to an embodiment of the present disclosure;
fig. 3 is a flowchart of an execution step of a comprehensive controller in a comprehensive monitoring protection system for insulation, arc light and line selection of a power distribution network according to an embodiment of the present application;
fig. 4 is a waveform diagram of a detection result of a high-frequency pulse voltage according to an embodiment of the present application;
FIG. 5 is a waveform diagram of a fault power frequency zero sequence current component detection result provided by an embodiment of the present application;
FIG. 6 is a waveform diagram of the detection result of the fault high-frequency zero-sequence current component provided by the embodiment of the application;
fig. 7 is a phase diagram of a high frequency pulse voltage according to an embodiment of the present application.
Illustration of: 11-a coupled capacitance sensor; 12-detection impedance.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
The embodiment of the application provides a comprehensive monitoring protection system for power distribution network insulation, arc light and line selection, and particularly relates to a structural schematic diagram of the comprehensive monitoring protection system for power distribution network insulation, arc light and line selection in fig. 1.
The comprehensive monitoring protection system for the insulation, arc light and line selection of the power distribution network comprises a pulse voltage acquisition device, a broadband current acquisition device, a power frequency voltage acquisition device, a display module and a comprehensive controller, wherein the comprehensive controller is connected with the pulse voltage acquisition device, the broadband current acquisition device, the power frequency voltage acquisition device and the display module. The display module is used for displaying the data on a screen after receiving the data acquired by the controller and providing the data for field staff.
The pulse voltage acquisition device is arranged on the outlet side of each monitored switch cabinet and is used for acquiring high-frequency pulse voltage signals of the switch cabinet and sending the high-frequency pulse voltage signals to the comprehensive controller.
Further, referring specifically to fig. 2, the pulse voltage acquisition device is a three-phase sensor, and each phase of the three-phase sensor includes a coupling capacitance sensor 11 and a detection impedance 12. The coupling capacitance sensor 11 may be any type of capacitor, and its capacitance value is in the range of 10pF to 1 nF. The detection impedance 12 is capacitance, inductance, resistance or any combination of the three, and the working frequency band is as follows: 10 kHz-20 MHz.
The broadband current acquisition device is arranged on the outlet side of each monitored switch cabinet, and is used for acquiring broadband zero sequence current signals of the switch cabinet and sending the broadband zero sequence current signals to the comprehensive controller.
Furthermore, the broadband current acquisition device is an electromagnetic zero-sequence current transformer, a Hall current sensor, a Rogowski coil or any other sensor capable of detecting the zero-sequence current of the circuit. The working frequency band is as follows: 20 Hz-20 MHz.
The power frequency voltage acquisition device is connected with the switch cabinet bus and is used for acquiring a power frequency voltage signal of the switch cabinet and sending the power frequency voltage signal to the comprehensive controller.
Further, the power frequency voltage acquisition device is an electromagnetic voltage transformer, a photoelectric voltage transformer, a capacitive voltage transformer or any other sensor capable of detecting the power frequency voltage of the line.
Referring to fig. 3, a flowchart of the execution steps of the integrated controller provided in this embodiment is provided.
Step S101, according to the high-frequency pulse voltage signal, determining the amplitude value and the phase of the high-frequency pulse voltage.
And step S102, filtering and decomposing the broadband zero sequence current signal to determine a power frequency zero sequence current signal and a high frequency pulse current signal contained in the broadband zero sequence current signal.
Step S103, determining whether an insulation fault exists in the switch cabinet according to the high-frequency pulse voltage amplitude and the power frequency zero sequence current signal, or according to the high-frequency pulse voltage amplitude, the high-frequency pulse current signal and the power frequency zero sequence current signal, or according to the high-frequency pulse voltage amplitude, the high-frequency pulse voltage phase and the power frequency voltage signal. If yes, further judging the type of the insulation fault.
In some embodiments of the present application, in a system fault-free state, the high-frequency pulse voltage signal of each phase of each line is recorded as a noise pulse voltage amplitude Uc, where the noise pulse voltage amplitude Uc is a background noise signal. The start-up constant Uq is further determined to be 1.5Uc. Further determining that the ground fault setting value Ud of the high-frequency pulse voltage is 2Uq, or setting the ground fault setting value Ud according to the pulse voltage amplitude generated by the ground fault during the test.
And obtaining the maximum high-frequency pulse voltage amplitude.
And when the amplitude of the maximum high-frequency pulse voltage is greater than or equal to a preset starting fixed value for more than two times continuously, if so, judging that the switch cabinet has an insulation fault. And further judging whether the power frequency zero sequence current signal has zero rest characteristics, if so, judging that the insulation fault type is single-phase grounding fault. If not, judging the type of the insulation fault as tip discharge or creeping discharge.
Referring specifically to fig. 4 and 5, as can be seen from the waveform diagrams of the high-frequency pulse voltage detection results in fig. 4, the A, B, C three phases detect at least 5 high-frequency voltage signals in 4.5ms, 5.5ms, 14.5ms, 15.5ms and 17ms of a power frequency period, wherein the amplitude of two pulse signals in 5.5ms and 15.5ms is maximum, the amplitude of the a phase is about 5V, the amplitude of the b phase is about 3V, and the amplitude of the c phase is about 5V. The method meets the requirement that 2 or more maximum pulse voltages exist in the insulation fault monitoring method, the amplitude of the maximum pulse voltages is larger than the starting fixed value of the pulse voltage amplitude by 0.5V, and further judges whether the power frequency current zero-break characteristic exists or not.
The horizontal axis of FIG. 5 represents time/s and the vertical axis represents amplitude/A. As can be seen from the waveform diagram of the detection result of the fault power frequency zero sequence current component in FIG. 5, the fault current has zero-break characteristics at the zero crossing point, and the zero-break time is about 1ms.
And judging that the system has single-phase grounding fault.
Or when the maximum high-frequency pulse voltage amplitude is greater than or equal to the starting fixed value for more than two times continuously, if yes, judging that the switch cabinet has insulation faults. And further judging that the high-frequency pulse current signal has a phase characteristic according to the power frequency zero sequence current signal, and if so, judging that the insulation fault type is single-phase grounding fault. If not, judging the type of the insulation fault as tip discharge or creeping discharge.
Further, the determining, according to the power frequency zero sequence current signal, that the high frequency pulse current signal has a phase characteristic includes:
the phase corresponding to the maximum value of the high-frequency pulse current in two adjacent periods is firstly obtained.
Judging whether the phase corresponding to the maximum value of the high-frequency pulse current in two adjacent periods occurs when the power frequency zero sequence current passes through zero or not, wherein the phases are respectively positioned at preset current positions, the preset current positions comprise a first position and a second position which are synchronous with the phase relative to the power frequency zero sequence current, and the first position and the second position are used for synchronizing the phases of the power frequency zero sequence current, wherein: the phase value of the first position is
The phase value of the second position is +.>
Referring specifically to fig. 4 and 6, as can be seen from the waveform diagrams of the high-frequency pulse voltage detection results in fig. 4, the A, B, C three phases detect at least 5 high-frequency voltage signals in 4.5ms, 5.5ms, 14.5ms, 15.5ms and 17ms of a power frequency period, wherein the amplitude of the two pulse signals in 5.5ms and 15.5ms is maximum, the amplitude of the a phase is about 5V, the amplitude of the b phase is about 3V, and the amplitude of the c phase is about 5V. The method meets the requirement that 2 or more maximum pulse voltages exist in the insulation fault monitoring method, the amplitude of the maximum pulse voltages is larger than the starting fixed value of the pulse voltage amplitude by 0.5V, and further judges the phase characteristics of the high-frequency pulse current.
The horizontal axis of FIG. 6 represents time/s and the vertical axis represents amplitude/A. As can be seen from the waveform diagram of the detection result of the fault high-frequency zero-sequence current component in FIG. 6, the arc reburning generates high-frequency pulse current, the maximum value of the high-frequency pulse current occurs when the power frequency current passes through zero, and the phase is distributed in
And->
Within the range.
In conclusion, the system is judged to have single-phase earth fault.
Or when the maximum high-frequency pulse voltage amplitude is greater than a preset ground fault setting value for more than two times continuously, if yes, judging that the switch cabinet has an insulation fault. And further judging whether the phase of the high-frequency pulse voltage has a phase characteristic according to the power frequency voltage signal, and if so, judging that the type of the insulation fault is a single-phase grounding fault. If not, judging the type of the insulation fault as tip discharge or creeping discharge.
Further, the step of judging whether the high-frequency pulse voltage phase has a phase characteristic according to the power frequency voltage signal includes:
the phase corresponding to the maximum value of the high-frequency pulse voltage in two adjacent periods is firstly obtained.
Judging whether the phases corresponding to the maximum values of the high-frequency pulse voltages in two adjacent periods are respectively positioned at preset voltage positions, wherein the preset voltage positions comprise the power frequency electric powerThird and fourth positions of the synchronization phase, wherein: the phase value of the third position is
The phase value of the fourth position is +.>
Referring specifically to fig. 4 and 7, as can be seen from the waveform diagrams of the detection results of the high-frequency pulse voltage in fig. 4, at least 5 high-frequency voltage signals are detected in 4.5ms, 5.5ms, 14.5ms, 15.5ms and 17ms of one power frequency period, wherein the amplitude of the two pulse signals in 5.5ms and 15.5ms is maximum, the amplitude of the a phase is about 5V, the amplitude of the b phase is about 3V, and the amplitude of the c phase is about 5V. The method meets the requirement that 2 or more maximum pulse voltage signal amplitudes are larger than the ground fault setting value by 1V in the insulation fault monitoring method, and further judges the phase characteristics of the high-frequency pulse voltage.
In fig. 7, the horizontal axis represents time/ms and the vertical axis represents voltage/V. As can be seen from the high-frequency pulse voltage phase distribution diagram of FIG. 7, the maximum values of the high-frequency pulse voltages are respectively distributed at the positions of 5.5ms and 15.5ms of the power frequency period, the relative power frequency voltage phases are 99 degrees and 279 degrees, and the phase characteristics of 90 degrees +/-10 degrees and 270 degrees +/-10 degrees are satisfied.
In conclusion, the system is judged to have a ground fault.
Step S104, determining whether arc faults exist on bus equipment according to the high-frequency pulse voltage amplitude and the high-frequency pulse current signal. If yes, an arc light protection early warning is sent out, and arc light protection measures are taken.
Further, when the maximum high-frequency pulse voltage amplitude is greater than or equal to the starting fixed value for more than two times continuously and all the high-frequency pulse current phases are in the same phase, arc faults are judged to occur on the bus equipment, arc protection early warning is sent out, and arc extinction technology is adopted or a power supply side switch is tripped.
Step S105, determining whether a line has a ground fault according to the high-frequency pulse voltage amplitude and the high-frequency pulse current signal. If yes, the earth fault early warning is sent out, and earth fault protection measures are taken.
Further, when the maximum high-frequency pulse voltage amplitude is greater than or equal to the starting fixed value for more than two times continuously, if the high-frequency pulse current phase of a certain line is opposite to that of other lines, the line is judged to have a ground fault, and the line ground fault early warning is sent out, and an arc extinction technology is adopted or the line switch is tripped.
According to the technical scheme, the comprehensive monitoring protection system for the insulation, arc light and line selection of the power distribution network comprises a pulse voltage acquisition device, a broadband current acquisition device, a power frequency voltage acquisition device and a comprehensive controller connected with the pulse voltage acquisition device, the broadband current acquisition device and the power frequency voltage acquisition device.
In practical application, the integrated controller is configured to monitor the insulation fault of the switch cabinet and determine the type of the insulation fault according to the acquired operation parameters of the switch cabinet; the integrated controller can also monitor the isolated light fault of the switch cabinet and realize line selection and phase selection of the ground fault of the power distribution network. The power distribution equipment insulation fault monitoring device combines the insulation fault, the islanding protection and the line selection detection functions, has comprehensive functions and extremely high judgment accuracy, and has the advantages that (1) the device can monitor the power distribution equipment insulation fault, including point discharge, creeping discharge and grounding fault, especially high-resistance grounding fault; (2) means for monitoring arc protection of the power distribution device; (3) The device can realize line selection and phase selection of the ground fault of the power distribution network. The invention integrates the functions of insulation fault, arc protection and line selection detection. Compared with the prior art and equipment, the technical method and the device have the advantages of comprehensive functions, quick response, accurate judgment, high detection sensitivity and the like.
The foregoing detailed description has been provided for the purposes of illustration in connection with specific embodiments and exemplary examples, but such description is not to be construed as limiting the application. Those skilled in the art will appreciate that various equivalent substitutions, modifications and improvements may be made to the technical solution of the present application and its embodiments without departing from the spirit and scope of the present application, and these all fall within the scope of the present application. The scope of the application is defined by the appended claims.
Claims (7)
1. An insulation, arc light and line selection comprehensive monitoring protection system for a power distribution network, which is characterized by comprising: the device comprises a pulse voltage acquisition device, a broadband current acquisition device and a power frequency voltage acquisition device, and a comprehensive controller connected with the pulse voltage acquisition device, the broadband current acquisition device and the power frequency voltage acquisition device;
the pulse voltage acquisition device is arranged on the outlet side of each monitored switch cabinet, and is used for acquiring a high-frequency pulse voltage signal of the switch cabinet and sending the high-frequency pulse voltage signal to the comprehensive controller;
the broadband current acquisition device is arranged on the outlet side of each monitored switch cabinet, and is used for acquiring broadband zero sequence current signals of the switch cabinet and sending the broadband zero sequence current signals to the comprehensive controller;
the power frequency voltage acquisition device is connected with the switch cabinet bus and is used for acquiring a power frequency voltage signal of the switch cabinet and sending the power frequency voltage signal to the comprehensive controller;
the integrated controller is configured to perform the steps of:
determining a high-frequency pulse voltage amplitude and a high-frequency pulse voltage phase according to the high-frequency pulse voltage signal;
filtering and decomposing the broadband zero sequence current signal to determine a power frequency zero sequence current signal and a high frequency pulse current signal contained in the broadband zero sequence current signal;
determining whether an insulation fault exists in the switch cabinet according to the high-frequency pulse voltage amplitude and the power frequency zero sequence current signal, or according to the high-frequency pulse voltage amplitude, the high-frequency pulse current signal and the power frequency zero sequence current signal, or according to the high-frequency pulse voltage amplitude, the high-frequency pulse voltage phase and the power frequency voltage signal; if yes, judging the type of the insulation fault;
the step of judging the insulation fault type comprises the following steps:
obtaining the maximum high-frequency pulse voltage amplitude;
when the amplitude of the maximum high-frequency pulse voltage is greater than or equal to a preset starting fixed value for more than two times continuously, if so, judging that the switch cabinet has an insulation fault; judging whether the power frequency zero sequence current signal has zero rest characteristics or not, if so, judging that the type of the insulation fault is a single-phase grounding fault; if not, judging the type of the insulation fault to be tip discharge or creeping discharge;
or when the maximum high-frequency pulse voltage amplitude is greater than or equal to the starting fixed value for more than two times continuously, if yes, judging that the switch cabinet has insulation faults; judging that the high-frequency pulse current signal has a first phase characteristic according to the power frequency zero sequence current signal, and judging that the insulation fault type is single-phase grounding fault if the high-frequency pulse current signal has the first phase characteristic; if not, judging the type of the insulation fault to be tip discharge or creeping discharge;
or when the amplitude of the maximum high-frequency pulse voltage is more than twice continuously and is greater than a preset ground fault setting value, if so, judging that the switch cabinet has an insulation fault; judging whether the high-frequency pulse voltage phase has a second phase characteristic according to the power frequency voltage signal, if so, judging that the insulation fault type is single-phase grounding fault; if not, judging the type of the insulation fault to be tip discharge or creeping discharge;
determining whether arc faults exist on bus equipment according to the high-frequency pulse voltage amplitude and the high-frequency pulse current signal; if yes, an arc light protection early warning is sent out, and arc light protection measures are taken;
the step of judging whether arc faults exist on the bus equipment is as follows: when the maximum high-frequency pulse voltage amplitude is greater than or equal to the starting fixed value for more than two times continuously and all the high-frequency pulse current phases are in the same phase, arc faults on bus equipment are judged;
determining whether a line has a ground fault according to the high-frequency pulse voltage amplitude and the high-frequency pulse current signal; if yes, giving out an earth fault early warning and taking earth fault protection measures;
the step of judging whether the line has a ground fault is as follows: and when the maximum high-frequency pulse voltage amplitude is more than twice continuously and is more than or equal to the starting fixed value, if the phase of the high-frequency pulse current of one line is opposite to that of other lines, judging that the line has a ground fault.
2. The integrated monitoring protection system for power distribution network insulation, arc light, line selection according to claim 1, wherein the starting constant and the ground fault setting value are determined by:
in the system fault-free state, determining the noise pulse voltage amplitude according to the high-frequency pulse voltage amplitude of each phase of each line;
determining the starting constant value according to the noise pulse voltage amplitude;
and determining the ground fault setting value according to the starting setting value.
3. The integrated monitoring protection system for insulation, arc light and line selection of a power distribution network according to claim 1, wherein the step of determining that the high-frequency pulse current signal has a phase characteristic according to the power frequency zero sequence current signal comprises:
acquiring phases corresponding to the maximum values of the high-frequency pulse currents in two adjacent periods;
judging whether the phase corresponding to the maximum value of the high-frequency pulse current in two adjacent periods occurs when the power frequency zero sequence current passes through zero or not, wherein the phases are respectively positioned at preset current positions, the preset current positions comprise a first position and a second position which are synchronous with the phase relative to the power frequency zero sequence current, and the first position and the second position are used for synchronizing the phases of the power frequency zero sequence current, wherein: the first position is
The second position is->
4. The integrated monitoring protection system for insulation, arc light and line selection of a power distribution network according to claim 1, wherein the step of determining whether the phase of the high-frequency pulse voltage has a phase characteristic according to a power frequency voltage signal comprises the steps of:
acquiring phases corresponding to the maximum values of the high-frequency pulse voltages in two adjacent periods;
judging whether phases corresponding to the maximum values of the high-frequency pulse voltages in two adjacent periods are respectively located at preset voltage positions, wherein the preset voltage positions comprise a third position and a fourth position which are synchronous with respect to the power frequency voltage, and the third position and the fourth position are used for synchronizing the phases, wherein the phases are the same as the power frequency voltage: the third position is
The fourth position is +.>
5. The integrated monitoring and protecting system for power distribution network insulation, arc light and line selection according to claim 1, wherein the pulse voltage acquisition device is a three-phase sensor, and each phase comprises a coupling capacitance sensor and a detection impedance.
6. The integrated monitoring and protecting system for power distribution network insulation, arc light and line selection according to claim 1, wherein the broadband current acquisition device is an electromagnetic zero sequence current transformer, a Hall current sensor or a rogowski coil.
7. The integrated monitoring and protecting system for power distribution network insulation, arc light and line selection according to claim 1, wherein the power frequency voltage acquisition device is an electromagnetic voltage transformer, a photoelectric voltage transformer or a capacitive voltage transformer.
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