CN202735467U - Single-phase ground fault location apparatus - Google Patents
Single-phase ground fault location apparatus Download PDFInfo
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- CN202735467U CN202735467U CN2012203665817U CN201220366581U CN202735467U CN 202735467 U CN202735467 U CN 202735467U CN 2012203665817 U CN2012203665817 U CN 2012203665817U CN 201220366581 U CN201220366581 U CN 201220366581U CN 202735467 U CN202735467 U CN 202735467U
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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
A single-phase ground fault location apparatus comprises a signal injection device which is connected between a power line and ground and is used for detecting and determining the grounding and injecting modulated current signals to the ground, and a plurality of monitors which are disposed at multiple positions on a three-phase power circuit, detect injected signals returned from a grounding point, determine a fault, and output fault information. The signal injection device is arranged on a three-phase bus or an outlet of a transformer substation, and multiple groups of monitors are hung on the three-phase power circuit. A current signal with a special frequency is injected to the ground when a ground fault happens; only the monitor which is located between the signal injection device and a ground fault point can extract the current signal from carrier signals; and the monitor locally displays fault determination information and outputs the information in a radio frequency form. According to the single-phase ground fault location apparatus, the current signal injected by the signal injection device instead of the fault current is selected for determining the fault, and the fault is more reliably determined due to the fact that the signal is free from the affect of the ground resistance and the circuit length of the fault point.
Description
Technical field
The utility model relates to a kind of equipment of singlephase earth fault of the equipment of judging and search earth fault, particularly a kind of small current neutral grounding system.
Background technology
At present, distribution line adopts isolated neutral or the mode by grounding through arc mostly, is referred to as small current neutral grounding system.When singlephase earth fault occured, the capacitance current of system was only flow through in the trouble spot, and this electric current is less, did not affect the system power supply operation, but caused the voltage of earth-free phase to raise, and threatened the safety of line insulation porcelain vase.Porcelain insulator causes circuit breaker trip in case puncture can cause two relative ground circuits.For this reason, the product of some searching single-phase grounding failure positions or method are come out one after another.A kind of method is to inject the signal of particular frequencies (such as 220Hz) in the fault phase line by voltage transformer (VT) (PT).This signal is got back to signal source from earth fault line, earth point through the earth, consists of loop flow.Detect the signal of this particular frequencies with hand-held current field signal supervisory instrument, seek the place that descends to the particular frequencies signal along faulty line, be the position at earth fault place.Because the capacity of PT is very little, the power of Injection Signal and limited, this method can only detect the very little fault of grounding resistance.Just limited the marking current intensity of injecting when the stake resistance resistance is large, has made it be difficult to be detected by the current field signal supervisory instrument, success ratio is very low.For another example utility model patent 01109726.4 and 01118274.1 described method, shortage is to the cognition of small current neutral grounding system residual voltage and zero sequence impedance, three-phase transformer zero sequence impedance as telltale is too large, the marking current amplitude is uncontrollable, make the mode Injection Signal of disturbance by switch, this signal does not have fixing amplitude-frequency characteristic, and very strong randomness is arranged, there are inborn defective and mistake on the principle, have been difficult to operability and practical value.Therefore, also there are the improved place of needs in the judgement of the singlephase earth fault of present small current neutral grounding system and lookup method.
The utility model content
Search and judge the singlephase earth fault of small current neutral grounding system for solution, for defective and the not enough problem of prior art, the purpose of this utility model provides a kind of equipment of judging and searching the singlephase earth fault of small current neutral grounding system.
The singlephase earth fault positioning equipment that the utility model provides comprises:
The signal injection device, for detection of judging ground connection and injecting the current signal of modulation to the earth, it is installed in three-phase bus or the transformer station exit of transformer station, an end ground connection of this device, the other end connects line of electric force;
Some monitors are hung on respectively plurality of positions on the three-phase power circuit, and it detects the signal of the injection of returning from earth point as signal supervisory instrument, can export failure message after the failure judgement.
Compared with prior art, the beneficial effects of the utility model are:
1. the fault signature chosen of failure judgement is not the fault current when singlephase earth fault occurs, but the current signal of the specific amplitude-frequency that is injected by telltale, this signal is not subjected to the impact of trouble spot stake resistance and line length, and failure judgement is more reliable.
2. the transformer that adopts Z-type to connect is done the power supply of telltale, has a zero sequence impedance little, the advantage that the positive-negative sequence impedance is large, and the amplitude-frequency of Injection Signal is adjustable by the secondary inductance of arc suppression coil, and safe and reliable.
3. the employing electronic switching device has higher response quick-break, can open and close circuit at special angle, produces the current signal of specific amplitude-frequency.
Description of drawings
Fig. 1 is electrical principle sketch of the present utility model;
Fig. 2 is the electrical schematic diagram of implementation of the present utility model;
Fig. 3 is the waveform schematic diagram of Injection Signal in the utility model;
Fig. 4 is the schematic diagram during the Injection Signal carrier wave in the utility model;
Fig. 5 is the schematic diagram during the monitor detection in the utility model;
Fig. 6 is the process flow diagram during the monitor detection in the utility model;
Fig. 7 is the structured flowchart of monitor in the utility model.
Embodiment
The utility model provides the equipment of a kind of singlephase earth fault location.Comprise:
The signal injection device, for detection of judging ground connection and injecting the current signal of modulation to the earth, it is installed in three-phase bus or the transformer station exit of transformer station, an end ground connection of this device, the other end connects line of electric force;
Some monitors are hung on respectively plurality of positions on the three-phase power circuit, and it detects the signal of the injection of returning from earth point as signal supervisory instrument, can export failure message after the failure judgement.
Described signal injection device comprises grounding transformer, voltage transformer (VT), arc suppression coil, controlled inductance, wherein: described grounding transformer is the transformer that the neutral point Z-type of drawing connects, its former limit is connected with power circuit, are connected former limit and are connected in neutral point and the former limit of voltage transformer (VT) with arc suppression coil, residual voltage can appear in neutral point when earth fault occured; The former edge joint of described voltage transformer (VT) is used for the residual voltage of the neutral point of monitoring grounding transformer between the neutral point and the earth of ground transformer; The former edge joint of described arc suppression coil is between the neutral point of ground transformer and the earth and secondary connects controlled inductance; Described controlled inductance is comprised of modulation telefault and electronic switch, when residual voltage appears in the secondary that monitors voltage transformer (VT), the conduction angle of control electronic switch, produce the current signal of specific amplitude and frequency by the modulation inductance, this signal injects the earth by the former limit coupling of arc suppression coil.
Described monitor comprises voltage transformer (VT), current transformer, microprocessor, and wherein: described voltage transformer (VT) is a capacitance type potential transformer, for detection of phase voltage; Described current transformer is an Open Type Electric Current Mutual Inductor, for detection of phase current; Described microprocessor is the high-speed low-power-consumption chip, is used for judging having or not of Injection Signal in conjunction with the amplitude versus frequency characte of electric current and voltage.
The neutral point of described grounding transformer is an artificial neutral point of making, be used for connecting arc suppression coil, during system generation earth fault, this grounding transformer is high impedance to the positive sequence negative-sequence current, zero-sequence current is low resistivity, make the Injection Signal action message, when singlephase earth fault occured, neutral point produced residual voltage.
Described monitor inside arranges a metal polar plate that is parallel to the earth, consist of condenser divider, voltage for detection of electrical lead, the inner integrated microprocessor of monitor extracts the signal that injects from carrier signal, export failure message by radio-frequency module after the failure judgement, to be used for the failure message remote monitoring.
Below in conjunction with accompanying drawing specific embodiments of the present utility model being done equipment further specifies.
Fig. 1 is electrical principle sketch of the present utility model, is comprised of ground connection three-phase transformer T, arc suppression coil L, controlled inductance K and monitor G.Three-phase transformer T is through arc suppression coil L ground connection, controlled inductance K and arc suppression coil L electromagnetic coupled, and monitor G is arranged on the three-phase feeder line.
Below in conjunction with more excellent conceptual scheme 2, discuss in detail implementation process of the present utility model.Signal injection device one end directly is connected with the three-phase feeder line, and the other end is connected with the earth.Wherein grounding transformer input end 1. is connected with the three-phase feeder line with disconnector F through fuse insurance FU, and the former limit of this grounding transformer is that Z-type connects (or claiming the meander configuration wiring), and provides an artificial neutral point to system.Grounding transformer has unique electromagnetic property in addition, and the positive sequence negative-sequence current is high impedance, only flows through very little exciting current in the winding.Because two windings are around on the contrary on each core limb, two windings flow through equal zero-sequence current and present Low ESR on the concentric column, and the pressure drop of zero-sequence current on winding is very little.Also namely when system's generation earth fault, in winding, will flow through positive sequence, negative phase-sequence and zero-sequence current.This winding presents high impedance to positive sequence and negative-sequence current, and concerning zero-sequence current, owing to connect in two winding reversed polarity of same phase, its induction electromotive force equal and opposite in direction, opposite direction is just in time cancelled out each other, and therefore is Low ESR.When singlephase earth fault occured, residual voltage appearred in the neutral point of this transformer, can be used as the power supply of Injection Signal.A wherein arc suppression coil end 2. and the neutral point link of grounding transformer, the direct ground connection of the other end requires stake resistance less than 4 ohm.When singlephase earth fault occured, residual voltage appearred in the former limit of this arc suppression coil, and the current controlled controlled inductance in its secondary that flows through that arc suppression coil enters ground 3..Controlled inductance forms by modulating telefault L and controllable silicon S1 and S2, special angle in phase voltage, trigger controlled silicon conducting, produce the current signal of certain amplitude-frequency, the former limit that this current signal is coupled to arc suppression coil enters ground, when flowing through the silicon controlled undercurrent with maintenance controllable silicon afterflow conducting, the controllable silicon cut-off, also just finish the modulated process of a signal, the waveform of the modulating current of arc suppression coil secondary as shown in Figure 3, trigger controlled silicon conducting when being chosen in voltage fundamental zero crossing front 45 and spending, flow through the silicon controlled undercurrent after the voltage fundamental zero passage when keeping controllable silicon afterflow conducting, the controllable silicon cut-off.The amplitude of signal and frequency can realize by regulating modulation telefault and silicon controlled conduction angle.
Above-mentioned modulation signal enters ground through arc suppression coil, through the earth fault scene, is returned by fault phase.The load current of modulation signal and power feeder is superimposed and forms as shown in Figure 4 carrier signal.The coded system of modulation signal adopts the Manchester's cde rule, when adjacent two cycles do not change relatively, also is that section does not have modulation signal or section that modulation signal is arranged, expression information " 0 "; When adjacent two cycles had relative variation, namely cycle did not have modulation signal and another cycle has modulation signal, expression information " 1 " yet; Adopt this coding rule can effectively avoid the load current signal on the impact of modulated current signal, because the load current signal has stable periodicity, and modulated current signal, in a cycle, occur once or not occurring, with adjacent cycle signal unchanged come judgement information " 1 " and " 0 " are arranged, can greatly improve the reliability of communication.
The monitor G that is installed on the power feeder has or not modulation signal by judging in the carrier signal, judges whether self is positioned on the fault loop, that is to say no between signal injection device and earth fault.The extraction flow process of modulation signal as shown in Figure 5.Current transformer is obtained current signal, is voltage signal through impedance transformation, and this voltage signal is made difference operation after the time-delay of a cycle with without the voltage signal of time-delay, and difference result is to the digital to analog converter of microprocessor.For the power frequency component of 50Hz, the time-delay of a cycle is 20ms.This differential voltage signal is called rectified signal, mainly keeps modulated current signal, only remaining very little load current signal.The result of logarithmic mode converter obtains filtering signal after processing with a digital band-pass filter, and this signal namely is whether the current signal of adjacent two cycles changes, as shown in Figure 6.Be easy to judge that by this filtering signal data message is " 1 " or " 0 ".Monitor receives specific data message (for example continuous 8 information " 1 "), can judge self to be in fault loop.Specific serial data sequence is sent by the signal injection device modulates.
The frequency of the passband design dependency of digital band-pass filter when the modulating apparatus modulation signal is in the situation that coupling can obtain best filter effect.Second order digital filtering transport function is:
Being connected neutral point with the earth respectively and being connected in voltage transformer (VT) former limit 4. with grounding transformer, is used for the residual voltage of the neutral point of monitoring grounding transformer, can be used for having judged whether that singlephase earth fault occurs.
The theory diagram of monitor comprises following functional module as shown in Figure 7: load current signal element, real-time clock crystal oscillator unit, differential current signal unit, battery supply monitoring means, voltage signal unit, radio communication interface unit, microprocessor.Load current signal element is used for measuring the load current of power feeder; Real-time clock crystal oscillator unit provides the precise time clock for monitor; The differential current signal unit is used for extracting the modulation signal that injects; The battery supply monitoring means is used for the supervision of the power status of monitor; The voltage signal unit is used for the phase voltage of monitoring power feeder; The radio communication interface unit is used for extending out communication and the parameter tuning that wireless radio frequency modules is finished failure message; Microprocessor is the core of monitor, especially extracts the modulation signal that injects and finishes in the microprocessor internal computing.
The above only is preferred implementation of the present utility model; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the utility model principle; can also make some improvement, these improvement also should be considered as protection domain of the present utility model.
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012203665817U CN202735467U (en) | 2012-07-26 | 2012-07-26 | Single-phase ground fault location apparatus |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012203665817U CN202735467U (en) | 2012-07-26 | 2012-07-26 | Single-phase ground fault location apparatus |
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| CN202735467U true CN202735467U (en) | 2013-02-13 |
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| CN2012203665817U Withdrawn - After Issue CN202735467U (en) | 2012-07-26 | 2012-07-26 | Single-phase ground fault location apparatus |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102778636A (en) * | 2012-07-26 | 2012-11-14 | 北京飞举电气有限公司 | Single-phase ground fault location method and apparatus |
| CN103337833A (en) * | 2013-06-17 | 2013-10-02 | 山东电力工程咨询院有限公司 | Grounding transformer protection action criteria |
| CN105676071A (en) * | 2016-02-29 | 2016-06-15 | 国家电网公司 | High-resistance control method for fault line selection |
| CN107340416A (en) * | 2017-08-28 | 2017-11-10 | 国网江西省电力公司电力科学研究院 | A kind of distribution network failure indicator LC tunings are outer to apply signal source |
| CN110927515A (en) * | 2019-11-14 | 2020-03-27 | 长沙理工大学 | Power distribution network single-phase earth fault line selection method and system based on grounding transformer tap grounding |
-
2012
- 2012-07-26 CN CN2012203665817U patent/CN202735467U/en not_active Withdrawn - After Issue
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102778636A (en) * | 2012-07-26 | 2012-11-14 | 北京飞举电气有限公司 | Single-phase ground fault location method and apparatus |
| CN102778636B (en) * | 2012-07-26 | 2016-03-02 | 北京飞举电气有限公司 | Method for locating single-phase ground fault and equipment |
| CN103337833A (en) * | 2013-06-17 | 2013-10-02 | 山东电力工程咨询院有限公司 | Grounding transformer protection action criteria |
| CN103337833B (en) * | 2013-06-17 | 2015-08-05 | 山东电力工程咨询院有限公司 | A kind of method of grounded transformer protection action |
| CN105676071A (en) * | 2016-02-29 | 2016-06-15 | 国家电网公司 | High-resistance control method for fault line selection |
| CN107340416A (en) * | 2017-08-28 | 2017-11-10 | 国网江西省电力公司电力科学研究院 | A kind of distribution network failure indicator LC tunings are outer to apply signal source |
| CN110927515A (en) * | 2019-11-14 | 2020-03-27 | 长沙理工大学 | Power distribution network single-phase earth fault line selection method and system based on grounding transformer tap grounding |
| CN110927515B (en) * | 2019-11-14 | 2022-01-25 | 长沙理工大学 | Power distribution network single-phase earth fault line selection method and system based on grounding transformer tap grounding |
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| Date | Code | Title | Description |
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| AV01 | Patent right actively abandoned |
Granted publication date: 20130213 Effective date of abandoning: 20160302 |
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| AV01 | Patent right actively abandoned |
Granted publication date: 20130213 Effective date of abandoning: 20160302 |
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| C25 | Abandonment of patent right or utility model to avoid double patenting |