CN103176103A - Overhead power distribution line single-phase grounding fault positioning method - Google Patents
Overhead power distribution line single-phase grounding fault positioning method Download PDFInfo
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- CN103176103A CN103176103A CN2013100846222A CN201310084622A CN103176103A CN 103176103 A CN103176103 A CN 103176103A CN 2013100846222 A CN2013100846222 A CN 2013100846222A CN 201310084622 A CN201310084622 A CN 201310084622A CN 103176103 A CN103176103 A CN 103176103A
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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
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- 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 relates to an overhead power distribution line single-phase grounding fault positioning method based on space magnetic field waveform characteristics, and belongs to the technical field of faults of an electric power system. The method includes arranging fault indicators and positioning faults by a time-difference-of-arrival method through a mobile measurement device. When a power distribution line is in heavy-current (>/=7A) fault, the fault indicators act to realize positioning of faults correctly; and when the power distribution line is in low-current (<7A) fault, the fault indicators do no actions, fault branches are cut off from branch points, and single-peak pulse signals are injected into a transformer substation. The method has high accuracy and can be used for solving the problem about positioning of overhead power distribution line single-phase grounding faults, and has important application in the technical field of fault detection of the electric power system.
Description
Technical field
The present invention relates to a kind of overhead distribution method for locating single-phase ground fault, relate in particular to the overhead distribution method for locating single-phase ground fault based on the space magnetic field waveform characteristic, belong to the electric power system fault technical field.
Background technology
In the Operation of Electric Systems process, often can break down, the power failure outside the plan that fault causes makes produces the confusion of pausing, live, and even jeopardizes the person and device security, forms very serious consequence.The statistical data demonstration of electric system, the fault great majority in the power distribution network operational process are short troubles, and are wherein singlephase earth fault more than 90%.The main cause that produces short circuit is the phase insulation of electrical equipment current carrying part or relatively insulate damaged.Therefore, after power distribution network generation singlephase earth fault, if can realize locating fast and accurately, not only can repair as early as possible circuit, guarantee power supply reliability, also safety and stability and the economical operation of whole electric system be had very important effect.
Traditional method is successively to draw the road to select fault wire, then finds out earth fault by artificial line walking ocular estimate.Draw the road route selection to cause non-fault wire user's unnecessary power failure.A large amount of manpower and materials are expended in range estimation line walking location, incur loss through delay positioning time.These two kinds of methods and modern power network increasingly automated extremely inadaptable.For decades, countless work about electric power persons is for solving route selection and locating automation issues and carried out extensive work, and research work never stopped.By numerous experts, scholar's effort, the route selection problem has obtained important breakthrough, and the route selection accuracy of novel line selection apparatus is not less than 95%, can satisfy the power distribution network operation to the requirement of route selection.But the singlephase earth fault orientation problem of power distribution network does not have much progress, also adopts the old way of artificial visually examine's line walking always, has a strong impact on the power distribution network power supply reliability.
After the route selection problem solved, domestic and international numerous experts and scholars had carried out a series of researchs for the individual event earth fault orientation problem of power distribution network, have also obtained many location theory and localization method.Such as domestic fault detector method, S signal injection method, traveling wave method etc. are arranged.
The fault detector ratio juris be in transformer station to fault phase bus Injection Signal electric current, this marking current is sent by transformer station, enters the earth return signal source through failure path by ground current.The pointer detection of failure path is moved to fault current.Fault detector generally partly is comprised of electric current, voltage and time detecting, fault distinguishing, indicating fault driving, malfunction indication and signal output and automatic time-delay reset control etc.Most of product adopts mechanical type rotating board turning indication fault, and circuit normally operates to a kind of color indication, becomes another kind of color during line fault, also has the small part product to adopt luminous indication fault.The excellent point of fault detector method is that structure and principle are simple, and low price is installed easily, and the user is reflected the practical function of display device for short circuit or reasonable.Shortcoming is to determine the concrete fault branch of circuit, affected by impedance ground, is not suitable for the system of neutral ground.Therefore, the result of use of earth-fault indicator is not bery desirable, and accuracy is not high, usually not reaction during electrical network generation singlephase earth fault.As seen, the earth-fault indicator technology can not satisfactorily resolve the distribution network failure orientation problem.
S signal injection method is the method that the positioning combination of single-phase grounding selecting and earth point is got up.Principle is after fault occurs, and injects the electric signal (frequency of Injection Signal is between power frequency nth harmonic and n+1 subharmonic, 220Hz commonly used) of characteristic frequency to ground wire by bus PT.Injection Signal can inject the earth through earth point along faulty line, detects at take-off point with fault detector, has the branch that signal flows through to be fault branch.Hand-held fault detector continuous detecting along the line on fault branch is according to the signal characteristic localization of faults on circuit.The advantage of the method is to use simply, not affected by arc suppression coil, and isolated neutral system and neutral by arc extinction coil grounding system are all applicable.Shortcoming is the Injection Signal finite energy, easily is subject to the impact of ground connection transition resistance and line distribution capacitance, therefore be not suitable for the large or long circuit of the excessive resistance of ground connection.But the method locating effect is subject to the impact of ground connection transition resistance and line distribution capacitance, in the situation that the ground connection transition resistance is large, the long meeting of circuit be located unsuccessfully.The S injection method does not have thoroughly to solve the singlephase earth fault orientation problem of small current neutral grounding system
The principle of traveling wave method is to utilize the characteristics of circuit upward traveling wave transmission to carry out localization of fault.Traveling wave method carries out localization of fault can be divided into Single Terminal Traveling Wave Fault Location and both-end travelling wave ranging.The principle of Single Terminal Traveling Wave Fault Location is at bus place's detection travelling wave signal, identifying after the reflection wave of trouble spot, according to ripple round trip between bus place and trouble spot time and velocity of wave propagation used, calculate fault distance, travelling wave signal wherein may be the transient state travelling wave of fault moment generation, may be also the capable ripple that the artificial pulse signal that injects in faulty line causes.The principle of both-end travelling wave ranging is the travelling wave signal in the detection failure generation simultaneously of the two ends of circuit, arrives definite abort situation of mistiming at circuit two ends according to the fault ripple.The advantage of traveling wave method is directly to locate fault distance and fault branch, does not need line walking, and locating speed is fast.Shortcoming is when the ground connection transition resistance is large, circuit branch hands over when many, and travelling wave signal will greatly weaken, and therefore, traveling wave method is only applicable to the situation that the ground connection transition resistance is little, branch is few.
Also have in addition to use and reach the method that time difference method measurement space Electromagnetic Wave Propagation carries out localization of fault.Step-out time method location is to arrive the moment of each monitoring station by the electromagnetic signal of measuring the fault current generation, and arrives a kind of localization method of the mistiming calculative determination abort situation of each monitoring station according to fault-signal.As shown in Figure 1, E1, E2, E3 are 3 monitoring points in circuit, and the high-precise synchronization clock is set on it.When the coordinate of these monitoring points is known, establish the moment that fault-signal arrives each monitoring station to be respectively T1, T2, T3, can calculate the mistiming that fault-signal arrives each monitoring station is respectively T12, T23, T13.
Wherein:
T
12=T
1-T
2，T
22=T
2-T
3，T
13=T
1-T
3
Three time differences can draw three pairs of hyperbolic curves, and hyp intersection point is the trouble spot of circuit, and the hyp equation of standard is:
A=T in formula
12(c/2), c is the light velocity
B=(S/2)
2-a
2, S is two distances between the monitoring station
In the mistiming of monitoring, only have two to be separate, get T12 and T13.That corresponding with this two mistimings is two hyperbolic curve L12 and L13.These two hyperbolic curves generally have two intersection points (as shown in Figure 1): some A1 and A2 are exactly the point of this circuit generation earth fault with the crossing point of overhead distribution in two intersection points.But the step-out time method is only applicable to determine the position of lightning fault.
Summary of the invention
For mentioning overhead distribution individual event earth fault orientation problem in the above-mentioned background technology, the present invention proposes the overhead distribution single-phase fault localization method based on the space magnetic field waveform characteristic.
Technical scheme of the present invention is when large current failure occurs, to use the fault detector method based on the induction electromotive force of changes of magnetic field; When low current fault occurs, adopt the portable localization of fault based on step-out time.
The method step is as follows:
Step 1: put fault detector;
Step 2: when the fault of large electric current (＞=7A) occured in circuit, fault was correctly located in the fault detector action;
Step 3: when in circuit, little electric current (﹤ 7A) fault occuring, fault detector is failure to actuate, and from take-off point open failure branch road, injects unimodal pulse signal in transformer station;
Step 4: carry traverse measuring device and use the arrival time difference method to locate fault.
The present invention is based on the overhead distribution method for locating single-phase ground fault that the space magnetic field waveform characteristic is carried out.
In said method, described current sorting technique is to calculate according to the conclusion of deriving based on Maxwell equation group and Lorentz gauge.This conclusion is i=I for electric current in the overhead distribution of random length in the space
0During sin ω t, at the induction electromotive force apart from the position of this circuit r be
Wherein, the magnetic permeability of closed-loop path curved surface is μ
r, area is that S, coil turn are N.
The described fault detector of the method is the fault detector that a kind of induction electromotive force of the space magnetic field generation based on changing moves.
The described low current fault localization method based on the step-out time method of the method is the time difference that the converted quantity by detection failure rear space magnetic field arrives different monitoring points to realize localization of fault.
The monitoring device of the described step-out time method of the method be not placed on the pole line distribution line under, be placed on when having the position near the ground of 20 times far away of shaft tower height at least apart from transmission line of electricity, can accurately monitor the space magnetic field waveform that earth current produces.
The described step-out time method of the method requires the clock high-precise synchronization (time sensitivity reaches 100ns) on each monitoring station.
The invention provides a kind of high accuracy that has, can be used for instructing the method that solves overhead distribution singlephase earth fault orientation problem.Has important application in the Power System Faults Detection technical field.
Description of drawings
Fig. 1 is TOA difference locating principle figure
Fig. 2 is that schematic diagram is put in the fault detector suspension.
Fig. 3 is that the circuit space magnetic field that fault detector is housed changes schematic diagram.
Fig. 4 is traverse measurement fault-signal schematic diagram.
Fig. 5 is process flow diagram of the present invention.
Embodiment
Below in conjunction with accompanying drawing, the present invention is further elaborated.Should be emphasized that, following explanation is only exemplary, rather than in order to limit the scope of the invention and to use.
A kind of overhead distribution method for locating single-phase ground fault, the method contains in steps:
(1) put fault detector:
As requested, fault detector is made the square coil of 15cm*15cm.Coil winding is that on 2000 ferrite, number of turns is 500 circles at relative permeability.Space magnetic field directivity characteristics after analysis of failure around circuit can draw hanging position and the placing direction of fault detector.
In overhead distribution, when the circuit on being erected at shaft tower does not have angle to change, when fault detector hangs, perpendicular to the plane of shaft tower and circuit composition, as shown in Fig. 2 (a); When in overhead distribution, angle pole being arranged, fault alarm S is suspended on the angular bisector of corner circuit institute gyration and plane that shaft tower forms, as shown in Fig. 2 (b).
(2) when the fault of large electric current (＞=7A) occurs in circuit, the fault detector action, correctly locate fault:
Do not occur at circuit on the shaft tower of angle variation, fault detector is placed according to Fig. 2 (a).When circuit does not have earth fault, space magnetic field around the coil S of fault detector is as shown in Fig. 3 (a), only has the magnetic field that produces along the horizontal current of pole line direction, magnetic field and coil place plane parallel, on coil, the influence electricity kinetic potential produces, at this moment, fault detector does not move.After large current failure occurs in circuit, space magnetic field around the coil S of fault detector is as shown in Fig. 3 (b), the space magnetic field parallel with coil S except the line current generation, the space magnetic field perpendicular to coil S that also has earth current to produce, the variation magnetic field of this moment can produce induction electromotive force on coil S, the energy of this electromotive force can the driving malfunction indicator motion.
On angle pole, circuit changes through angle can occur after shaft tower, and fault detector is placed according to Fig. 2 (b), and its principle of work is identical with common shaft tower.When circuit did not have fault, the space magnetic field that the electric current in the pole line of shaft tower two ends produces was through the vector stack, and its direction is identical with the angular bisector of two circuits, thereby with coil S place plane parallel, on coil, the influence electricity kinetic potential produces, and at this moment, fault detector does not move.After large current failure occured circuit, earth current produced and plane, coil S place space magnetic field at an angle.At this moment, the changing magnetic field in coil causes that coil produces induction electromotive force, and this electromotive force can the driving malfunction indicator motion.
(3) when in circuit, little electric current (﹤ 7A) fault occuring, fault detector is failure to actuate, and from take-off point open failure branch road, injects unimodal pulse signal in transformer station:
When low current fault occured in circuit, the field signal that produces due to earth current is weak the annihilation too, and fault detector is failure to actuate.Due to after breaking down through large impedance earth, the field signal of generation is more weak, is easily fallen into oblivion by ground unrest, fault branch need to be opened circuit, and Injection Signal reaches the requirement that realizes localization of fault again.
(4) carrying traverse measuring device uses the arrival time difference method to locate fault:
Fig. 4 is the schematic diagram of metering system.In figure, the P point is the trouble spot, when the fault detector method can't be carried out localization of fault, fault branch is opened circuit, and add signal source S by transformer station, and S is a unimodal pulse producer.M, N are respectively two traverse measuring devices (can be vehicle-mounted), the time of arrival that is used for measuring fault-signal.Host computer control S sends pulse, time is designated as zero constantly, and the fault-signal that pulse produces arrives measurement point M, arrives measurement point N through T2 through T1, has produced poor T12 time of arrival, mistiming can be determined a pair of hyperbolic curve thus, and the intersection point of hyperbolic curve and circuit is the trouble spot.
Fig. 5 is process flow diagram of the present invention, is a kind of high accuracy that has, and can be used for instructing the method that solves overhead distribution singlephase earth fault orientation problem, has important application in Power System Faults Detection.
The above; only for the better embodiment of the present invention, but protection scope of the present invention is not limited to this, anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement are within all should being encompassed in protection scope of the present invention.
Claims (5)
1. an overhead distribution method for locating single-phase ground fault, is characterized in that, the method comprises the following steps:
Step 1: put fault detector;
Step 2: when the fault of large electric current (＞=7A) occured in circuit, fault was correctly located in the fault detector action;
Step 3: when in circuit, little electric current (﹤ 7A) fault occuring, fault detector is failure to actuate, and from take-off point open failure branch road, injects unimodal pulse signal in transformer station;
Step 4: carry traverse measuring device and use the arrival time difference method to locate fault.
2. a kind of overhead distribution method for locating single-phase ground fault according to claim 1, is characterized in that, described fault detector is the fault detector that a kind of induction electromotive force of the space magnetic field generation based on changing moves.
3. a kind of overhead distribution method for locating single-phase ground fault according to claim 1, it is characterized in that, the method for described step-out time legal position fault is the time difference that the converted quantity by detection failure rear space magnetic field arrives different monitoring points to realize localization of fault.
4. a kind of overhead distribution method for locating single-phase ground fault according to claim 1, it is characterized in that, the monitoring device of described step-out time method be not placed on the pole line distribution line under, and be placed on the position near the ground that has 20 times far away of shaft tower height apart from transmission line of electricity at least.
5. a kind of overhead distribution method for locating single-phase ground fault according to claim 1, is characterized in that, the clock high-precise synchronization on described step-out time method each monitoring station, and time sensitivity reaches 100ns.
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| CN104198895A (en) * | 2014-09-16 | 2014-12-10 | 湖南华大紫光科技股份有限公司 | Wind farm cable fault locating method |
| CN105137285A (en) * | 2015-08-28 | 2015-12-09 | 广东中钰科技股份有限公司 | Power distribution network grounding fault line selection method and system |
| CN105576623A (en) * | 2016-01-29 | 2016-05-11 | 中国电力科学研究院 | Time difference method based adaptive half wavelength line differential protection method |
| CN108318765A (en) * | 2016-05-25 | 2018-07-24 | 黄雪峰 | A kind of power fault detection method |
| CN108414875A (en) * | 2018-03-14 | 2018-08-17 | 中广核工程有限公司 | A kind of localization method and system of the large-scale enclosed busbar shell Abnormal Grounding of detection |
| CN110376485A (en) * | 2019-07-29 | 2019-10-25 | 北京派克盛宏电子科技有限公司 | Transmission line malfunction detection, localization method and equipment based on space magnetic induction |
| CN112345978A (en) * | 2020-10-27 | 2021-02-09 | 云南电网有限责任公司临沧供电局 | Ground fault positioning method based on two-phase injection pulse at low-voltage side of distribution transformer |
| CN113030651A (en) * | 2021-03-31 | 2021-06-25 | 国网上海市电力公司 | Method for positioning impact surge current |
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Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104198895A (en) * | 2014-09-16 | 2014-12-10 | 湖南华大紫光科技股份有限公司 | Wind farm cable fault locating method |
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| CN105576623A (en) * | 2016-01-29 | 2016-05-11 | 中国电力科学研究院 | Time difference method based adaptive half wavelength line differential protection method |
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| CN105576623B (en) * | 2016-01-29 | 2020-01-17 | 中国电力科学研究院 | Self-adaptive half-wavelength line differential protection method based on time difference method |
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| CN108445325A (en) * | 2016-05-25 | 2018-08-24 | 黄雪峰 | A kind of power fault detection system |
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| CN108414875A (en) * | 2018-03-14 | 2018-08-17 | 中广核工程有限公司 | A kind of localization method and system of the large-scale enclosed busbar shell Abnormal Grounding of detection |
| CN108414875B (en) * | 2018-03-14 | 2020-03-27 | 中广核工程有限公司 | Positioning method and system for detecting abnormal grounding of large-scale enclosed bus shell |
| CN110376485A (en) * | 2019-07-29 | 2019-10-25 | 北京派克盛宏电子科技有限公司 | Transmission line malfunction detection, localization method and equipment based on space magnetic induction |
| CN112345978A (en) * | 2020-10-27 | 2021-02-09 | 云南电网有限责任公司临沧供电局 | Ground fault positioning method based on two-phase injection pulse at low-voltage side of distribution transformer |
| CN112345978B (en) * | 2020-10-27 | 2024-02-06 | 云南电网有限责任公司临沧供电局 | Ground fault positioning method based on distribution transformer low-voltage side two-phase injection pulse |
| CN113030651A (en) * | 2021-03-31 | 2021-06-25 | 国网上海市电力公司 | Method for positioning impact surge current |
| CN113030651B (en) * | 2021-03-31 | 2023-03-14 | 国网上海市电力公司 | Method for positioning impact surge current |
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