CN116430165A - Power grid fault detection device and method - Google Patents
Power grid fault detection device and method Download PDFInfo
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- CN116430165A CN116430165A CN202310280274.XA CN202310280274A CN116430165A CN 116430165 A CN116430165 A CN 116430165A CN 202310280274 A CN202310280274 A CN 202310280274A CN 116430165 A CN116430165 A CN 116430165A
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
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- 238000012360 testing method Methods 0.000 description 2
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- 238000013024 troubleshooting Methods 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
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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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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
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Abstract
The invention discloses a power grid fault detection device and a method, wherein the power grid fault detection device comprises a portable power supply and a detection device, wherein the portable power supply is used for outputting direct current, the detection device is connected with the portable power supply and is used for converting the direct current output by the portable power supply into alternating current pulse voltage, and the alternating current pulse voltage is applied to a power grid line to be detected according to a preset program so as to detect single-phase or phase-to-phase faults of the power grid. When alternating current with a certain frequency passes through the voltage transformer or the transformer, the inductance impedance is very large at the moment and is similar to a resistor with very large resistance, namely, the situation that the two phases are disconnected at the position of the voltage transformer and the transformer can not cause false detection is considered, so that the power grid fault detection device provided by the embodiment of the invention can perform fault finding without releasing the voltage transformer and the transformer when detecting a line, thereby greatly saving the cost of manpower and material resources and improving the fault detection efficiency.
Description
Technical Field
The invention belongs to the technical field of power grid fault detection, and particularly relates to a power grid fault detection device and method.
Background
The power supply transmission of the power grid line is the guarantee of the normal operation of a national power system, the power grid line is intricate and complex, the geographical environment where the power grid line is located is severe, and the problem of power grid line faults frequently occurs. The power supply of the power grid line is cut off in time after the power grid line breaks down, so that the problem is solved, the process is time-consuming, the power supply safety of a region and even a city is seriously affected, and huge economic loss is caused for local power departments. Therefore, the fault area is rapidly and accurately positioned, faults are removed in time, and the power supply recovery as early as possible is an urgent problem to be solved by power maintenance personnel and power departments.
At present, two main ways of troubleshooting the power grid fault are available in the market: one is to use the traditional resistance measurement mode, namely use the megameter to carry on the problem to find out; the second is to conduct troubleshooting by a withstand voltage test method, that is, using a direct current withstand voltage tester. The voltage transformer on the high-voltage transmission line needs to be released before detection, a large amount of manpower and material resources are consumed, the time consumption is long, the operation difficulty is high, and the danger is high.
Disclosure of Invention
The invention provides a power grid fault detection device and a power grid fault detection method, which can perform fault finding without removing a voltage transformer and a transformer, greatly save the cost of manpower and material resources and improve the fault detection efficiency.
In a first aspect, the present invention provides a power grid fault detection device, including:
a portable power supply for outputting direct current;
the detection device is connected with the portable power supply and is used for converting direct current output by the portable power supply into alternating current pulse voltage and applying the alternating current pulse voltage to a power grid line to be detected according to a preset program so as to detect single-phase faults or phase-to-phase faults of the power grid.
Optionally, the detection device comprises a digital control system, a pulse power supply and a change-over switch module;
the digital control system is connected with the portable power supply, and the portable power supply provides working power for the digital control system;
the digital control system is connected with the pulse power supply, the pulse power supply is respectively connected with the portable power supply and the change-over switch module, and the pulse power supply converts direct current output by the portable power supply into alternating current pulse voltage under the control of the digital control system;
the digital control system is connected with the change-over switch module and is used for controlling the change-over switch module to act according to a preset program and applying the alternating current pulse voltage to a power grid line to be detected.
Optionally, the change-over switch module includes a first switch, a second switch, a third switch, a fourth switch and a fifth switch;
the first end of the first switch is connected with the pulse power supply, and the second end of the first switch is connected with a first phase line of the power grid;
the first end of the second switch is connected with the pulse power supply, and the second end of the second switch is connected with a second phase line of the power grid;
the first end of the third switch is connected with the pulse power supply, and the second end of the third switch is connected with a third phase line of the power grid;
the first end of the fourth switch is connected with the second end of the second switch, and the second end of the fourth switch is grounded;
the first end of the fifth switch is connected with the second end of the third switch, and the second end of the fifth switch is grounded;
the control end of the first switch, the control end of the second switch, the control end of the third switch, the control end of the fourth switch and the control end of the fifth switch are all connected with the digital control system.
Optionally, the first switch, the second switch, the third switch, the fourth switch and the fifth switch are relay switches or IGBT switches.
Optionally, the pulse power supply comprises an inversion module, a boosting module and a feedback module;
the inversion module is respectively connected with the digital control system and the portable power supply and is used for converting direct current output by the portable power supply into alternating current pulse voltage with preset frequency under the control of the digital control system;
the boosting module is respectively connected with the digital control system and the inversion module and is used for boosting the alternating current pulse voltage output by the inversion module under the control of the digital control system;
the feedback module is respectively connected with the boosting module and the digital control system, and is used for collecting the alternating current pulse voltage output by the boosting module and feeding back the alternating current pulse voltage to the digital control system, and the control system controls the inversion module and the boosting module to regulate according to feedback information so as to output stable alternating current pulse voltage.
Optionally, the amplitude of the pulse voltage output by the detection device is continuously adjustable within the range of 0-20 kV.
In a second aspect, the present invention provides a power grid fault detection method, based on the power grid fault detection device provided in the first aspect of the present invention, including:
after the detection equipment is electrified, converting direct current output by the portable power supply into alternating current pulse voltage;
and applying the alternating current pulse voltage to a power grid line to be detected according to a preset program.
Optionally, the detection device includes a digital control system, a pulse power supply, and a switch module, where the switch module includes a first switch, a second switch, a third switch, a fourth switch, and a fifth switch; the first end of the first switch is connected with the pulse power supply, and the second end of the first switch is connected with a first phase line of the power grid; the first end of the second switch is connected with the pulse power supply, and the second end of the second switch is connected with a second phase line of the power grid; the first end of the third switch is connected with the pulse power supply, and the second end of the third switch is connected with a third phase line of the power grid; the first end of the fourth switch is connected with the second end of the second switch, and the second end of the fourth switch is grounded; the first end of the fifth switch is connected with the second end of the third switch, and the second end of the fifth switch is grounded; the control end of the first switch, the control end of the second switch, the control end of the third switch, the control end of the fourth switch and the control end of the fifth switch are all connected with the digital control system, and the alternating current pulse voltage is applied to a power grid line to be detected according to a preset program, and the method comprises the following steps:
controlling the first switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a first phase power grid circuit to be detected so as to detect a first phase line fault;
controlling the second switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a second phase power grid circuit to be detected so as to detect a second phase line fault;
and controlling the third switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a third phase power grid circuit to be detected so as to detect a third phase line fault.
Optionally, the ac pulse voltage is applied to the power grid line to be detected according to a preset program, and the method further includes:
controlling the first switch and the fourth switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a first phase power grid circuit to be detected so as to detect phase-to-phase faults of a first phase circuit and a second phase circuit;
controlling the first switch and the fifth switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a first phase power grid circuit to be detected so as to detect phase-to-phase faults of a first phase circuit and a third phase circuit;
and controlling the second switch and the fifth switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a second phase power grid circuit to be detected so as to detect the phase-to-phase faults of the second phase line and the third phase line.
The power grid fault detection device provided by the embodiment of the invention comprises a portable power supply and detection equipment, wherein the portable power supply is used for outputting direct current, the detection equipment is connected with the portable power supply and is used for converting the direct current output by the portable power supply into alternating current pulse voltage, and the alternating current pulse voltage is applied to a power grid line to be detected according to a preset program so as to detect single-phase faults or interphase faults of the power grid. Because the inductance in the voltage transformer and the transformer has the characteristics of direct current passing and alternating current isolating, when alternating current with certain frequency passes through the voltage transformer or the transformer, the inductance impedance is very large at the moment and is similar to a resistor with very large resistance, namely, the two phases are considered to be disconnected at the position of the voltage transformer and the transformer, and the situation of false detection is not caused.
Drawings
The invention is described in further detail below with reference to the drawings and examples.
FIG. 1 is a schematic diagram of a grid power supply circuit;
fig. 2 is a schematic structural diagram of a power grid fault detection device according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a detection device according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a switch module according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a pulse power supply according to an embodiment of the present invention;
FIG. 6 is an equivalent circuit diagram of grid transmission;
fig. 7 is a flowchart of a power grid fault detection method according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.
In the description of the present invention, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for providing a special meaning.
Fig. 1 is a schematic diagram of a power supply line of a power grid in which a large number of voltage transformers (Potential Transformer, PT) and transformers are present, which are similar to the voltage transformers and are the means for transforming the voltages. However, the purpose of voltage transformation of the transformer is to conveniently transmit electric energy, so that the capacity is very large, and is generally calculated by kilovolt-amperes or megavolt-amperes, while the purpose of voltage transformation of the voltage transformer is mainly to supply power to a measuring instrument and a relay protection device, to measure the voltage, the power and the electric energy of a line, or to protect valuable equipment, a motor and a transformer in the line when the line fails, so that the capacity of the voltage transformer is very small, generally only a few volt-amperes or tens of volt-amperes, and is not more than one kilovolt-ampere at maximum. The voltage transformer and the transformer have the function of mutual inductance besides energy transmission in the circuit, and have the characteristics of direct connection and disconnection because the voltage transformer and the transformer are similar to an inductor. When direct current is applied to the lines by adopting a traditional resistance measurement or voltage withstand test mode, if faults of two lines are detected, the inductance is smaller, when the direct current passes through the inductance, the inductance is similar to a wire, the two lines are communicated, and at the moment, the two lines are in a short circuit state, so that false detection is caused, the detection cannot be carried out by adopting a direct current mode, and if the direct current detection is required, the voltage transformer and the transformer in the lines can be removed. The voltage transformer and the transformer are installed at a high position, so that a large amount of manpower and material resources are consumed, the time is long, the operation difficulty is high, and the danger is high.
In view of the foregoing, an embodiment of the present invention provides a power grid detection apparatus, including:
a portable power supply for outputting direct current;
the detection device is connected with the portable power supply, and is used for converting direct current output by the portable power supply into alternating current pulse voltage, and applying the alternating current pulse voltage to a power grid line to be detected according to a preset program so as to detect single-phase faults or phase-to-phase faults of the power grid.
In the embodiment of the present invention, the portable power source may be a storage battery, for example, a lithium ion battery, a lead acid battery, etc., which is not limited herein. The portable power source is used for outputting direct current. The detection device is connected with the portable power supply, and is used for converting direct current output by the portable power supply into required alternating current pulse voltage, and applying the alternating current pulse voltage to a power grid line to be detected according to a preset program so as to detect single-phase faults or phase-to-phase faults of the power grid. For example, when single-phase fault detection is performed, an ac pulse voltage is applied to one of the phase lines, current and voltage data of the phase line are collected, single-phase faults are detected, when inter-phase fault detection is performed, an ac pulse voltage is applied to one of the phase lines to be detected, current and voltage data are collected on the other phase line, and inter-phase faults are detected. For example, if a single-phase fault is detected, current and voltage data cannot be collected if an open-circuit fault exists, and if an interphase short-circuit fault exists during interphase fault detection, current and voltage data can be detected, so that the fault type can be judged according to the collected current and voltage data.
Because the inductance in the voltage transformer and the transformer has the characteristics of direct current passing and alternating current isolating, when alternating current with certain frequency passes through the voltage transformer or the transformer, the inductance impedance is very large at the moment and is similar to a resistor with very large resistance, namely, the two phases are considered to be disconnected at the position of the voltage transformer and the transformer, and the situation of false detection is not caused.
The grid fault detection device of the present invention will be described below by way of example with reference to specific embodiments, and it should be noted that the following embodiments are illustrative of the present invention, and not limiting of the present invention.
Fig. 2 is a schematic structural diagram of a power grid fault detection device according to an embodiment of the present invention, where, as shown in fig. 2, the power grid fault detection device includes a portable power source 110 and a detection apparatus 120.
The portable power source 110 is configured to output direct current to power the detection device 120. For example, in one embodiment of the present invention, portable power source 110 may be a lithium ion battery. The portable power supply 110 has the advantages of light weight, portability and the like, is suitable for various complex terrains, and can meet the test requirement all the day after being charged once.
The detection device 120 is connected to the portable power source 110, and is configured to convert the dc power output by the portable power source 110 into an ac pulse voltage, and apply the ac pulse voltage to a power grid line to be detected according to a preset program, so as to detect a single-phase fault or an inter-phase fault of the power grid. Illustratively, when a single phase is required to be detected, for example, a single phase fault is detected on the a-phase line, an ac pulse voltage is applied to the a-phase line, current and voltage data of the a-phase line are collected at a remote end, and the single phase fault of the a-phase line is detected; in the case of detecting an inter-phase fault, for example, A, B, an ac pulse voltage is applied to the a-phase line, current and voltage data are collected on the B-phase line, and A, B is detected.
Fig. 3 is a schematic structural diagram of a detection device according to an embodiment of the present invention, and as shown in fig. 3, in some embodiments of the present invention, the detection device includes a digital control system 121, a pulse power source 122, and a switch module 123.
The digital control system 121 is connected to a portable power source, and the portable power source provides working power for the digital control system 121.
The digital control system 121 is connected with a pulse power supply 122, the pulse power supply 122 is respectively connected with a portable power supply and a change-over switch module 123, and the pulse power supply 122 converts direct current output by the portable power supply into alternating current pulse voltage under the control of the digital control system 121. For example, in an embodiment of the present invention, the digital control system 121 may control the frequency and amplitude of the ac pulse voltage output by the pulse power source 122 to meet the detection requirements.
The digital control system 121 is connected to the switch module 123, and is used for controlling the switch module to act according to a preset program, and applying an ac pulse voltage to the power grid line to be detected. Illustratively, when unidirectional failure detection is performed on the a-phase line, the switch module 123 is operated, the ac pulse voltage output by the pulse power source 122 is applied to the a-phase line, when unidirectional failure detection is performed on the B-phase line, the switch module 123 is operated, the ac pulse voltage output by the pulse power source 122 is applied to the B-phase line, when unidirectional failure detection is performed on the C-phase line, the switch module 123 is operated, when phase-to-phase failure detection is performed on the A, B phase, the switch module 123 is operated, the ac pulse voltage output by the pulse power source 122 is applied to the a-phase or B-phase line, when phase-to-phase failure detection is performed on the A, C phase, the switch module 123 is operated, and when phase-to-phase failure detection is performed on the B, C phase, the ac pulse voltage output by the pulse power source 122 is applied to the B-phase or C-phase line.
Fig. 4 is a schematic structural diagram of a switch module according to an embodiment of the present invention, which further illustrates the switch module, and exemplary, as shown in fig. 4, in some embodiments of the present invention, the switch module includes a first switch a, a second switch B, a third switch C, a fourth switch B1, and a fifth switch C1. The first end of the first switch A is connected with the pulse power supply, and the second end of the first switch A is connected with a first phase line (namely an A-phase line) of the power grid; the first end of the second switch B is connected with the pulse power supply, and the second end of the second switch B is connected with a second phase line (namely a B-phase line) of the power grid; the first end of the third switch C is connected with the pulse power supply, and the second end of the third switch C is connected with a third phase line (namely a C-phase line) of the power grid; the first end of the fourth switch B1 is connected with the second end of the second switch B, and the second end of the fourth switch B1 is grounded; the first end of the fifth switch C1 is connected with the second end of the third switch C, and the second end of the fifth switch C1 is grounded; the control end of the first switch a, the control end of the second switch B, the control end of the third switch C, the control end of the fourth switch B1 and the control end of the fifth switch C1 are all connected with a digital control system (not shown in the figure).
Illustratively, in the embodiment of the present invention, the unidirectional failure detection process is: the digital control system automatically detects A, B, C three-phase lines one by one according to the flow. When the phase A line is detected, the digital control system controls the first switch A to be turned on, and the other switches B, B and C, C1 are turned off; when the phase B line is detected, the digital control system controls the second switch B to be turned on, and the other switches A, B and C, C1 are turned off; when the C-phase line is detected, the digital control system controls the switch C to be turned on, the other switches A, B, B and C1 are turned off, the pulse power supply is controlled to output pulse voltage with certain frequency and amplitude, then the single-phase fault is detected through the collection of voltage and current signals in the equipment, and the detection result can be automatically displayed.
Illustratively, in the embodiment of the present invention, the interphase fault detection process is: the inter-phase line fault detection is divided into three types of A-B inter-phase fault detection, A-C inter-phase fault detection and B-C inter-phase fault detection, when the A-B inter-phase fault detection is carried out, a first switch A and a fourth switch B1 are conducted, the other switches B, C, C1 are disconnected, after the automatic switching of the switches is completed, a pulse power supply outputs pulse voltage with certain frequency and amplitude to be applied to an A-phase line, then judgment is carried out according to voltage and current signals collected by the inside of the equipment, and the judgment result is displayed; when detecting an A-C phase fault, the first switch A and the fifth switch C1 are turned on, the other switches B, B and C are turned off, and pulse voltage output by the pulse power supply is applied to an A phase line; when the phase-B-C fault is detected, the second switch B and the fifth switch C1 are turned on, the other switches A, B and C are turned off, and the pulse voltage output by the pulse power supply is applied to the phase-B line.
In some embodiments of the present invention, the first switch a, the second switch B, the third switch C, the fourth switch B1, and the fifth switch C1 are relay switches or IGBT switches, and embodiments of the present invention are not limited herein.
In the traditional fault detection method, after one path is detected each time, the detection needs to be manually operated and replaced to another path for detection, so that the operation difficulty is high and the operation is complex. As described above, the change-over switch module can realize automatic line switching during single-phase detection and phase-to-phase detection, and the program of the digital control system controls the on and off of different switches, so that single-phase and phase-to-phase fault detection can be completed without manual switching, and the fault detection efficiency is improved.
Fig. 5 is a schematic structural diagram of a pulse power supply according to an embodiment of the present invention, and as shown in fig. 5, in some embodiments of the present invention, the pulse power supply includes an inverter module 1221, a boost module 1222, and a feedback module 1223.
The inverter module 1221 is connected to the digital control system and the portable power source, respectively, and is configured to convert the dc power output by the portable power source into an ac pulse voltage with a preset frequency under the control of the digital control system. The boost module 1222 is connected to the digital control system and the inverter module 1221, respectively, and is configured to boost the ac pulse voltage output by the inverter module 1221 under the control of the digital control system.
The feedback module 1223 is connected to the boost module 1222 and the digital control system, respectively, and is used for collecting the ac pulse voltage output by the boost module 1222 and feeding back to the digital control system. The control system controls the inverter module 1221 and the boost module 1222 to adjust according to the feedback information to output a stable ac pulse voltage.
Because of the specificity of the power grid line, the power supply transmission line of the power grid is generally used for power transmission of about 10kV, but the highest voltage of some insulating devices on the line can reach about 15kV, so that if the fault detection is carried out on the power grid line, the detection voltage needs to be close to or higher than the insulating voltage of the devices to be detected accurately. In some embodiments of the invention, the amplitude of the pulse voltage output by the detection device is continuously adjustable within the range of 0-20kV, and the detection requirement can be met for all insulation faults on the transmission line of the power grid.
Fig. 6 is an equivalent circuit diagram of power grid transmission, as shown in fig. 6, because of the special structure of the power grid transmission line, the three-phase electric wire is similar to three parallel wires, and the distances between the three wires are relatively close, so that the same capacitor C is arranged between the wires, the larger the distributed capacitance between the wires is along with the increase of the distance, the conducting internal resistance R is arranged on the transmission line, and the internal resistance R is gradually increased along with the increase of the distance between the wires. At present, the power grid detection equipment in the market is direct current detection output, because the output power of the equipment is smaller, when the direct current detection equipment is used for detecting, the power supply is similar to the charging process of a power supply to a capacitor C, as the distance of a transmission line increases, the resistor R increases, the longer the charging time is, the more energy is consumed on the power grid line, the more energy is consumed in the detection process all the time, and the output voltage of the direct current equipment is low, so that the detection distance of a traditional detection mode is short.
In the embodiment of the invention, the alternating current pulse voltage is adopted for detection, the pulse voltage is up to 20kV, the pulse energy storage capacitor is larger, and the instantaneous power output by each pulse is larger, so that the distributed capacitor can be charged to the voltage required for detection in a short time when each pulse works, and the power is supplied by the front-stage lithium battery, so that sufficient energy can be provided for detection equipment, and the power grid fault detection device can meet the requirement of ultra-long-distance power grid line fault detection.
The embodiment of the invention also provides a power grid fault detection method, based on the power grid fault detection device provided by any of the foregoing embodiments of the invention, fig. 7 is a flowchart of the power grid fault detection method provided by the embodiment of the invention, and as shown in fig. 7, the power grid fault detection method includes:
s101, after the detection equipment is electrified, converting direct current output by the portable power supply into alternating current pulse voltage.
S102, applying alternating current pulse voltage to a power grid line to be detected according to a preset program.
The power grid fault detection device is described in detail in the foregoing embodiments, and the embodiments of the present invention are not described herein again.
After the detection equipment is electrified, the direct current output by the portable power supply is converted into alternating current pulse voltage. The detection device applies alternating current pulse voltage to the power grid line to be detected according to a preset program so as to detect single-phase faults or phase-to-phase faults of the power grid. For example, when single-phase fault detection is performed, an alternating current pulse voltage is applied to one phase line, current and voltage data of the phase line are collected, single-phase faults are detected, when interphase fault detection is performed, an alternating current pulse voltage is applied to one phase line to be detected, current and voltage data are collected on the other phase line, and interphase faults are detected.
In some embodiments of the present invention, as shown in fig. 3 and 4, the detection device includes a digital control system, a pulse power supply, and a switch module including a first switch a, a second switch B, a third switch C, a fourth switch B1, and a fifth switch C1. The first end of the first switch A is connected with the pulse power supply, and the second end of the first switch A is connected with a first phase line (namely an A-phase line) of the power grid; the first end of the second switch B is connected with the pulse power supply, and the second end of the second switch B is connected with a second phase line (namely a B-phase line) of the power grid; the first end of the third switch C is connected with the pulse power supply, and the second end of the third switch C is connected with a third phase line (namely a C-phase line) of the power grid; the first end of the fourth switch B1 is connected with the second end of the second switch B, and the second end of the fourth switch B1 is grounded; the first end of the fifth switch C1 is connected with the second end of the third switch C, and the second end of the fifth switch C1 is grounded; the control end of the first switch a, the control end of the second switch B, the control end of the third switch C, the control end of the fourth switch B1 and the control end of the fifth switch C1 are all connected with a digital control system (not shown in the figure). Applying an alternating current pulse voltage to a power grid line to be detected according to a preset program, wherein the alternating current pulse voltage comprises the following components:
1. the first switch is controlled to be closed, the other switches are opened, and alternating current pulse voltage is applied to a first phase power grid circuit to be detected, so that first phase line faults are detected.
For example, when detecting the phase a line, the first switch a is turned on, the other switches B, B, C, C are turned off, then the high-voltage pulse power supply outputs a high-voltage pulse voltage with a certain frequency and pulse width, the high-voltage pulse voltage is divided into three gears, namely, 10kV gear, 15kV gear and 20kV gear, each gear is detected 3-5 times, namely, 10kV gear detection is automatically performed 3-5 times, if the line is normal, 15kV gear detection is automatically performed 3-5 times, if the line is normal, 20kV gear detection is performed 3-5 times, if the line is normal, the line jumps directly to the next phase (phase B) line for detection, and when three gears in one phase are detected, if one gear detects the line fault, the next gear detection is not performed any more (if the line fault is detected in 10kV gear, 15kV and 20kV gear detection are not performed any more), but the phase line jumps directly to the next phase line for detection.
2. And controlling the second switch to be closed, opening the other switches, and applying alternating current pulse voltage to a second phase power grid circuit to be detected so as to detect a second phase line fault.
When the phase B line is detected, the switch B is turned on, and the switches A, B1 and C, C1 are turned off; and then the high-voltage pulse power supply outputs high-voltage pulse voltage with certain frequency and pulse width, the high-voltage pulse voltage is divided into three gears, namely 10kV gear, 15kV gear and 20kV gear, each gear is detected 3-5 times, namely, the 10kV gear is detected 3-5 times, if the line is normal, the 15kV gear is automatically detected 3-5 times, if the line is normal, the 20kV gear is detected 3-5 times, if the line is normal, the line is directly jumped to the next phase (C phase) line for detection, and when three gears in one phase are detected, if a certain gear detects the line fault, the next gear is no longer detected (if the 10kV gear does not detect the line fault any more, the 15kV and 20kV gears are not detected), and the next phase line is directly jumped to for detection.
3. And controlling the third switch to be closed, opening the other switches, and applying alternating current pulse voltage to a third phase power grid circuit to be detected so as to detect a third phase line fault.
When a C-phase line is detected, the switch C is turned on, the switches A, B, B and C1 are turned off, the high-voltage pulse power supply automatically outputs high-voltage pulse voltage with certain frequency and pulse width according to program setting, the high-voltage pulse voltage is divided into three gears, namely 10kV gear, 15kV gear and 20kV gear, each gear is detected for 3-5 times, namely 10kV gear is detected for 3-5 times, 15kV gear detection is automatically carried out if the line is normal, 20kV gear detection is automatically carried out after 3-5 times of 15kV gear detection, a display screen automatically pops out three-phase line detection results if the line is normal, in addition, when the C-phase three gears are detected, when a certain gear detects a line fault, next gear and next phase detection are not carried out, and the detection results are directly popped out.
4. And controlling the first switch and the fourth switch to be closed, opening the other switches, and applying alternating current pulse voltage to a first phase power grid circuit to be detected so as to detect phase-to-phase faults of the first phase circuit and the second phase circuit.
When the phase-A-B fault detection is carried out, the switch A and the switch B1 are conducted, the switch B, C, C is disconnected, when the switch is automatically switched, the high-voltage pulse power supply outputs high-voltage pulse voltage with certain frequency and pulse width, the high-voltage pulse voltage is divided into two gears during the phase-to-phase detection, namely 3kV gears and 5kV gears, each gear is detected for 3-5 times, if a line is normal after 3-5 times of 3kV gear detection, the 5kV gear detection is automatically carried out, the next phase (A-C phase) detection is automatically carried out after 3-5 times of 5kV gear detection, and when the 3kV gear detection is carried out, the 5kV gear detection is not carried out any more, and the next phase detection is directly jumped.
5. And controlling the first switch and the fifth switch to be closed, opening the other switches, and applying alternating current pulse voltage to a first phase power grid circuit to be detected so as to detect the phase-to-phase faults of the first phase circuit and the third phase circuit.
When detecting the A-C phase, the switch A and the switch C1 are turned on, and the switches B, B1 and C are turned off; when the switch is automatically switched, the high-voltage pulse power supply outputs high-voltage pulse voltage with certain frequency and pulse width, the high-voltage pulse voltage is divided into two gears, namely a 3kV gear and a 5kV gear, each gear is detected for 3-5 times, if the line is normal after 3-5 times of detection, the 5kV gear is automatically detected, the next phase (B-C phase) is automatically detected after 3-5 times of detection of the 5kV gear, and when the 3kV gear detects the line fault, the 5kV gear is not detected any more, and the next phase is directly jumped to for detection.
6. And controlling the second switch and the fifth switch to be closed, opening the other switches, and applying alternating current pulse voltage to a second phase power grid circuit to be detected so as to detect phase-to-phase faults of the second phase line and the third phase line.
When detecting the B-C phase, the switch B and the switch C1 are turned on, and the switches A, B and C are turned off; when the switch is automatically switched, the high-voltage pulse power supply outputs high-voltage pulse voltage with certain frequency and pulse width, the high-voltage pulse voltage is divided into two gears, namely a 3kV gear and a 5kV gear, each gear is detected for 3-5 times, if the line is normal after 3-5 times of detection of the 3kV gear, the 5kV gear is automatically detected, the detection result is automatically popped up after 3-5 times of detection of the 5kV gear, and in addition, when the 3kV gear detects the line fault in the B-C phase, the detection result is not popped up again after the 3kV gear is detected.
The power grid fault detection method provided by the embodiment of the invention adopts an automatic detection control system, adopts a high-voltage pulse mode with certain frequency and pulse width to output, simultaneously controls the system to automatically perform high-voltage switch combination switching, can perform automatic detection under the condition that a distribution network line does not need to be disconnected with a voltage transformer and a transformer, does not need manual operation to perform line switching detection, can simultaneously detect three-phase lines, has short detection time (the inter-phase detection time or the single-phase detection time is not more than 5 minutes at most), has a few minutes from the detection start time to the detection end time, and can display detection results in real time. In addition, the invention can detect various faults in the distribution network line on one device, especially can detect invisible faults which are extremely difficult to find, such as insulator insulation faults, the existing device can not detect without releasing PT and a transformer, and can only judge through experience of an maintainer, and the invention can detect various faults on the line without releasing PT and the transformer, thereby solving the pain point problems in circuit overhaul and fault investigation, thoroughly changing the way of power grid fault investigation, greatly improving overhaul efficiency and ensuring reliable operation of a power grid.
In the description herein, it should be understood that the terms "upper," "lower," "left," "right," and the like are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and to simplify operation, rather than to indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.
In the description herein, reference to the term "one embodiment," "an example," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in the foregoing embodiments, and that the embodiments described in the foregoing embodiments may be combined appropriately to form other embodiments that will be understood by those skilled in the art.
The technical principle of the present invention is described above in connection with the specific embodiments. The description is made for the purpose of illustrating the general principles of the invention and should not be taken in any way as limiting the scope of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of this specification without undue burden.
Claims (9)
1. A power grid fault detection device, comprising:
a portable power supply for outputting direct current;
the detection device is connected with the portable power supply and is used for converting direct current output by the portable power supply into alternating current pulse voltage and applying the alternating current pulse voltage to a power grid line to be detected according to a preset program so as to detect single-phase faults or phase-to-phase faults of the power grid.
2. The grid fault detection device of claim 1, wherein the detection apparatus comprises a digital control system, a pulsed power supply, and a diverter switch module;
the digital control system is connected with the portable power supply, and the portable power supply provides working power for the digital control system;
the digital control system is connected with the pulse power supply, the pulse power supply is respectively connected with the portable power supply and the change-over switch module, and the pulse power supply converts direct current output by the portable power supply into alternating current pulse voltage under the control of the digital control system;
the digital control system is connected with the change-over switch module and is used for controlling the change-over switch module to act according to a preset program and applying the alternating current pulse voltage to a power grid line to be detected.
3. The grid fault detection device of claim 2, wherein the diverter switch module comprises a first switch, a second switch, a third switch, a fourth switch, and a fifth switch;
the first end of the first switch is connected with the pulse power supply, and the second end of the first switch is connected with a first phase line of the power grid;
the first end of the second switch is connected with the pulse power supply, and the second end of the second switch is connected with a second phase line of the power grid;
the first end of the third switch is connected with the pulse power supply, and the second end of the third switch is connected with a third phase line of the power grid;
the first end of the fourth switch is connected with the second end of the second switch, and the second end of the fourth switch is grounded;
the first end of the fifth switch is connected with the second end of the third switch, and the second end of the fifth switch is grounded;
the control end of the first switch, the control end of the second switch, the control end of the third switch, the control end of the fourth switch and the control end of the fifth switch are all connected with the digital control system.
4. A grid fault detection device according to claim 3, wherein the first switch, the second switch, the third switch, the fourth switch and the fifth switch are relay switches or IGBT switches.
5. The grid fault detection device of any one of claims 2-4, wherein the pulsed power supply comprises an inverter module, a boost module, and a feedback module;
the inversion module is respectively connected with the digital control system and the portable power supply and is used for converting direct current output by the portable power supply into alternating current pulse voltage with preset frequency under the control of the digital control system;
the boosting module is respectively connected with the digital control system and the inversion module and is used for boosting the alternating current pulse voltage output by the inversion module under the control of the digital control system;
the feedback module is respectively connected with the boosting module and the digital control system, and is used for collecting the alternating current pulse voltage output by the boosting module and feeding back the alternating current pulse voltage to the digital control system, and the control system controls the inversion module and the boosting module to regulate according to feedback information so as to output stable alternating current pulse voltage.
6. The grid fault detection device of any one of claims 1-4, wherein the amplitude of the pulsed voltage output by the detection apparatus is continuously adjustable in the range of 0-20 kV.
7. A method for detecting a power grid fault, characterized in that it is based on the power grid fault detection device according to any one of claims 1-6, comprising:
after the detection equipment is electrified, converting direct current output by the portable power supply into alternating current pulse voltage;
and applying the alternating current pulse voltage to a power grid line to be detected according to a preset program.
8. The method of claim 7, wherein the detection device comprises a digital control system, a pulsed power supply, and a switcher module comprising a first switch, a second switch, a third switch, a fourth switch, and a fifth switch; the first end of the first switch is connected with the pulse power supply, and the second end of the first switch is connected with a first phase line of the power grid; the first end of the second switch is connected with the pulse power supply, and the second end of the second switch is connected with a second phase line of the power grid; the first end of the third switch is connected with the pulse power supply, and the second end of the third switch is connected with a third phase line of the power grid; the first end of the fourth switch is connected with the second end of the second switch, and the second end of the fourth switch is grounded; the first end of the fifth switch is connected with the second end of the third switch, and the second end of the fifth switch is grounded; the control end of the first switch, the control end of the second switch, the control end of the third switch, the control end of the fourth switch and the control end of the fifth switch are all connected with the digital control system, and the alternating current pulse voltage is applied to a power grid line to be detected according to a preset program, and the method comprises the following steps:
controlling the first switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a first phase power grid circuit to be detected so as to detect a first phase line fault;
controlling the second switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a second phase power grid circuit to be detected so as to detect a second phase line fault;
and controlling the third switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a third phase power grid circuit to be detected so as to detect a third phase line fault.
9. The grid fault detection method according to claim 8, wherein the ac pulse voltage is applied to the grid line to be detected according to a preset program, further comprising:
controlling the first switch and the fourth switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a first phase power grid circuit to be detected so as to detect phase-to-phase faults of a first phase circuit and a second phase circuit;
controlling the first switch and the fifth switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a first phase power grid circuit to be detected so as to detect phase-to-phase faults of a first phase circuit and a third phase circuit;
and controlling the second switch and the fifth switch to be closed, opening the other switches, and applying the alternating current pulse voltage to a second phase power grid circuit to be detected so as to detect the phase-to-phase faults of the second phase line and the third phase line.
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