CN101865967A - Device for single-phase earth fault line selection and method thereof - Google Patents

Device for single-phase earth fault line selection and method thereof Download PDF

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Publication number
CN101865967A
CN101865967A CN 201010203357 CN201010203357A CN101865967A CN 101865967 A CN101865967 A CN 101865967A CN 201010203357 CN201010203357 CN 201010203357 CN 201010203357 A CN201010203357 A CN 201010203357A CN 101865967 A CN101865967 A CN 101865967A
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China
Prior art keywords
disturbance
zero
circuit
earth fault
selection
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CN 201010203357
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姜新宇
陆国庆
余怀林
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GUANGZHOU ZHIGUANG ELECTRIC CO Ltd
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GUANGZHOU ZHIGUANG ELECTRIC CO Ltd
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Priority to CN 201010203357 priority Critical patent/CN101865967A/en
Publication of CN101865967A publication Critical patent/CN101865967A/en
Pending legal-status Critical Current

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Abstract

The invention provides a method for single-phase earth fault line selection and a method thereof. The device comprises an automatic line selection device, a disturbance source and a zero sequence current transformer, wherein the disturbance source is arranged on a system neutral point and transmits the disturbance to a zero sequence circuit of the system after receiving a disturbance command transmitted by the automatic line selection device; and the zero sequence current transformer is arranged on each line, is connected with the automatic line selection device and is used for sampling the disturbed zero sequence circuit current. The invention is not limited by the magnitude of the system capacitance current, earth types and other factors and can be used for reliably and accurately selecting an earth fault line.

Description

The devices and methods therefor of single-phase earth fault line selection
Technical field
The present invention relates to the small current earthing wire-selecting technology, be specifically related to a kind of devices and methods therefor of single-phase earth fault line selection.
Background technology
The single-phase earth fault line selection of small current neutral grounding system is a difficult problem that perplexs electric system for a long time, correctly selects ground path fast after single-phase earthing takes place safe operation of power system is played an important role.Earthing wire-selecting method and earthing wire-selecting protective device accurately, electric system had important contribution: judgement promptly and accurately and selectively excise earth fault, be grounded the selectivity action of fault, the operation of restriction system band singlephase earth fault, reduce the duration of singlephase earth fault, the safe operation of safeguards system; The switching overvoltage level of reduction system makes superpotential life period minimizings such as arc grounding; Reduce apparatus insulated pollution flashover accident rate, reduce the chance that forms two-phase strange land short circuit and alternate direct short-circuit; Can reduce power off time as far as possible, keep the continuity of power supply, thereby reduce the user, improve service level because of the loss that power failure causes to the user.
Since the microcomputer type line selection apparatus puts into operation, a lot of enterprises, R﹠D institution have successively proposed multiple route selection principle, and developed multiple product based on these route selection principles, but the route selection accuracy of these products is also lower, can not satisfy the requirement of power distribution automation development.Therefore, the automatic route selection technology is not widely used, and returns to the line selection mode of original manual line-by-line line guy again.
In resonant earthed system, when system capacitive current is big the route selection accuracy higher, but capacitance current hour route selection accuracy is low.Relevant therewith is, route selection accuracy higher (ground current is bigger) during common metal ground connection, and (ground current is less) route selection accuracy is low during high resistance ground.Singlephase earth fault when taking place in the distribution of neutral by arc extinction coil grounding, ground path electric weight feature shows different features according to the difference of arc suppression coil compensation mode, and the situation (crossing under the condition of repaying a kindness) that ground path and non-ground path have the same charge feature can occur, make that a plurality of route selection principles are no longer suitable as arc suppression coil.How to solve the single-phase earth fault line selection problem and become the key that can the resonance grounding mode be widely used.Therefore develop a kind of reliability, little electric current line selection apparatus that accuracy is high has important practical significance.
Summary of the invention
Primary and foremost purpose of the present invention is to overcome the shortcoming and defect of prior art, a kind of device of single-phase earth fault line selection is provided, be mainly used in resonant earthed system, this device is not subjected to the influence of factors such as system capacitive current size, earthing type, overcome problems such as the existing system method of operation, ground current be little, can select earth fault line reliably, exactly.
Another object of the present invention provides the method for single-phase earth fault line selection.
Primary and foremost purpose of the present invention is achieved through the following technical solutions: the device of single-phase earth fault line selection is characterized in that comprising: the automatic route selection device; Be installed in system neutral, after receiving the disturbance order that the automatic route selection device sends, the system zero sequence loop is sent the disturbing source of disturbance; Be installed on each circuit, that be connected with the automatic route selection device, be used for zero sequence current mutual inductor that zero sequence loop current after the disturbance is sampled.
Described disturbing source is controllable impedance, switching resistance or the switching capacitance in short-term in short-term in system neutral installing.
Another object of the present invention is achieved through the following technical solutions: the method for single-phase earth fault line selection may further comprise the steps:
Behind S1, the system's generation single-phase earthing, gather zero-sequence current before each circuit disturbance by the zero sequence current mutual inductor that is installed in each circuit;
S2, in the ground connection process, change system's zero sequence impedance, thereby produce disturbance by automatic route selection device control disturbing source;
After S3, disturbing source were produced disturbance, the automatic route selection device was gathered the zero-sequence current after each circuit disturbance again, calculated each forward and backward circuit zero sequence difference between current value Δ I of disturbance 0, and according to zero-sequence current difference DELTA I 0Each circuit is sorted, and the circuit of the forward and backward zero-sequence current difference of disturbance maximum is faulty line.
In the method for above-mentioned single-phase earth fault line selection, go back execution in step behind the execution in step S3:
S4, by switching value input/output module, communication module line number is sent or uploads after selecting faulty line.
Ultimate principle of the present invention is: at system neutral installing disturbing source, behind system's generation single-phase earthing, gather the zero-sequence current of each circuit by the zero sequence CT (current transformer) that is installed in each circuit, control disturbing source then and in the ground connection process, change system's zero sequence impedance in short-term among a small circle, the perturbation scheme of disturbing source has: change compensativity among a small circle by arc suppression coil, perhaps adopt switching resistance, switched capacitor etc. in short-term; After producing disturbance, gather the zero-sequence current of each circuit again, obtain the variable quantity of each circuit zero-sequence current before and after disturbance then, wherein the maximum is earth fault line.Because it equals the change value of disturbance front and back current perturbation, and All other routes are constant substantially.
The present invention has following advantage and effect with respect to prior art: principle is simple and clear, the criterion of determining earth fault line is not an absolute value, but relative value, it is the variable quantity of zero-sequence current, irrelevant with the polarity of zero sequence current mutual inductor, the influence of also having avoided zero sequence current mutual inductor and having measured factors such as loop errer and background interference, all accurately route selections under conditions such as the different capacitance current sizes of system, various earthing types have improved sensitivity and reliability; Do not influence arc suppression coil compensation in arc suppression coil earthing system, arc extinction compensation and route selection are parallel, and can repeatedly check the route selection result.
Description of drawings
Fig. 1 is a structural representation of the present invention;
Fig. 2 is the data acquisition module structural representation;
Fig. 3 is that main control module reaches the structural representation that is connected with peripheral module;
Zero-sequence current distribution plan when Fig. 4 is the circuit single-phase earthing;
Fig. 5 is a principle schematic of doing the disturbing source route selection with arc suppression coil;
Fig. 6 is a circuit zero sequence current waveform figure.
Embodiment
The present invention is described in further detail below in conjunction with embodiment and accompanying drawing, but embodiments of the present invention are not limited thereto.
Embodiment
As shown in Figure 1, the device of single-phase earth fault line selection of the present invention comprises the zero sequence CT (current transformer), automatic route selection device, the disturbing source that connect successively.Wherein zero sequence CT is installed on each circuit, finishes the sampling to each circuit zero-sequence current behind system's generation single-phase earthing, and sampled signal is delivered to the automatic route selection device.The automatic route selection device comprises main control module 3, power module 4, and the data acquisition module 1 that is connected with main control module 3 respectively, time module 6, switching value input/output module 2, communication module 7, demonstration and Keyboard Control module 5, data acquisition module 1 receives the sampled signal of zero sequence CT, and switching value input/output module 2 is connected with disturbing source; Power module 4 is connected with all the other each modules of automatic route selection device respectively, to they power supplies, and by optional 220V of actual conditions or 110V input (AC/DC universal).Disturbing source is installed in system neutral, and be controlled by the automatic route selection device, after receiving the disturbance order of sending by switching value input/output module 2 in the automatic route selection device system zero sequence loop is sent disturbance, and the disturbance confirmation signal is replied to the automatic route selection device by switching value input/output module 2; After the automatic route selection device is received the disturbance confirmation signal, finish sampling, the calculating of zero sequence loop current after the disturbance by zero sequence CT.During specific implementation, disturbing source can be in system neutral installing controllable impedance (as arc suppression coil), in short-term switching resistance or in short-term switching capacitance (be resistance, the electric capacity that may command input or excision are withdrawed from, to be selected go out circuit after, at once with its excision) etc.
As shown in Figure 2, described data acquisition module 1 mainly comprises current transformer, amplifying return circuit and the A/D conversion chip that connects successively, 40 tunnel simulating signals of gathering when current transformer normally moves in system enter the A/D conversion chip through amplifying return circuit, are connected with the input end of parallel bus mode with main control module 3 at A/D conversion chip output terminal.
As shown in Figure 3, described main control module 3 mainly comprises dsp processor, CPLD (ComplexProgrammable Logic Device, CPLD), house dog, and dsp processor is connected with CPLD, house dog respectively by bus; Main control module is isolated by photoelectricity and is linked to each other with the switching value input/output module, links to each other with data acquisition module, display keyboard control module, communication module respectively by bus.
The method of single-phase earth fault line selection of the present invention comprises the steps:
When A, system normally moved, the automatic route selection device was gathered the zero-sequence current of each circuit in real time.
Behind B, the system's generation single-phase earthing, gather zero-sequence current before each circuit disturbance by the zero sequence current mutual inductor that is installed in each circuit.
C, in the ground connection process, change system's zero sequence impedance, thereby produce disturbance by automatic route selection device control disturbing source; As control arc suppression coil change among a small circle compensativity, in short-term switching resistance, method such as switching capacitance all can realize the purpose of disturbance in short-term; The time that disturbance is kept can determine that general each disturbance is kept 2~3 power frequency cycles and got final product according to the zero-sequence current required time after the disturbance of automatic route selection device reliable samples.As shown in Figure 4, disturbing source and earth point form the zero-sequence current loop, promptly pass through the zero-sequence current I of disturbing source XFlow back to system by earth point, so the disturbance of disturbing source is not to having the greatest impact of producing of the faulty line II that earth fault is arranged, have influence substantially to non-fault line I, two circuit zero sequence current waveforms as shown in Figure 6.
After D, disturbing source were produced disturbance, the automatic route selection device was gathered the zero-sequence current after each circuit disturbance again, calculated each forward and backward circuit zero sequence difference between current value Δ I of disturbance 0, and according to zero-sequence current difference DELTA I 0Each circuit is sorted, and the circuit of the forward and backward zero-sequence current difference of disturbance maximum is faulty line.
Fig. 5 is the schematic diagram that is grounded failure line selection with arc suppression coil as disturbing source.The compensativity of supposing ground connection generation back arc suppression coil changes to the m point by the n point, and the inductance current of compensation is by I L(before the disturbance) is adjusted to I L' (after the disturbance) produced a disturbance quantity to system: Δ I like this L=I L-I L', arc suppression coil to the influence of non-fault line zero-sequence current promptly among the figure b point to a point, Δ I 0h=I 0a-I 0b≈ 0; Influence to the faulty line zero-sequence current is that the d point is to c point, Δ I 0f=I 0d-I 0c≈ Δ I L, because Δ I 0f>Δ I 0hSo, can judge Δ I 0Be the circuit of generation ground connection for the circuit of maximum.
E, by switching value input/output module, communication module line number is sent or uploads after selecting faulty line.
The foregoing description is a preferred implementation of the present invention; but embodiments of the present invention are not restricted to the described embodiments; other any do not deviate from change, the modification done under spirit of the present invention and the principle, substitutes, combination, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.

Claims (5)

1. the device of single-phase earth fault line selection is characterized in that comprising:
The automatic route selection device;
Be installed in system neutral, after receiving the disturbance order that the automatic route selection device sends, the system zero sequence loop is sent the disturbing source of disturbance;
Be installed on each circuit, that be connected with the automatic route selection device, be used for zero sequence current mutual inductor that zero sequence loop current after the disturbance is sampled.
2. the device of single-phase earth fault line selection according to claim 1 is characterized in that: described disturbing source is at the controllable impedance of system neutral installing, switching resistance or switching capacitance in short-term in short-term.
3. the method for single-phase earth fault line selection is characterized in that may further comprise the steps:
Behind S1, the system's generation single-phase earthing, gather zero-sequence current before each circuit disturbance by the zero sequence current mutual inductor that is installed in each circuit;
S2, in the ground connection process, change system's zero sequence impedance, thereby produce disturbance by automatic route selection device control disturbing source;
After S3, disturbing source are produced disturbance, the automatic route selection device is gathered the zero-sequence current after each circuit disturbance again, calculate each forward and backward circuit zero sequence difference between current value Δ I0 of disturbance, and according to zero-sequence current difference DELTA I0 each circuit is sorted, the circuit of the forward and backward zero-sequence current difference of disturbance maximum is faulty line.
4. the method for single-phase earth fault line selection according to claim 3 is characterized in that: described disturbing source is at the controllable impedance of system neutral installing, switching resistance or switching capacitance in short-term in short-term.
5. the method for single-phase earth fault line selection according to claim 3 is characterized in that behind the execution in step S3 also execution in step:
S4, by switching value input/output module, communication module line number is sent or uploads after selecting faulty line.
CN 201010203357 2010-06-18 2010-06-18 Device for single-phase earth fault line selection and method thereof Pending CN101865967A (en)

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102005741A (en) * 2010-10-29 2011-04-06 华北电力大学 Distribution network line single phase earthing fault diagnosis and isolation method and device
CN102435911A (en) * 2011-09-20 2012-05-02 江苏省电力公司宿迁供电公司 Automatic positioning system for single-phase earth fault of distribution line
CN102520314A (en) * 2011-11-23 2012-06-27 北京天能继保电力科技有限公司 Detection system and detection method for single-phase grounding fault line selection in small current grounding system
CN103424671A (en) * 2013-09-03 2013-12-04 刘天明 Low-current grounding fault manual discrimination line selection system of power system
CN104330709A (en) * 2014-11-28 2015-02-04 国家电网公司 Positioning method for single-phase earth fault sections of isolated neutral system
CN105223469A (en) * 2015-09-30 2016-01-06 国网浙江省电力公司绍兴供电公司 A kind of line-selected earthing device being applicable to intelligent substation
CN108008248A (en) * 2017-11-27 2018-05-08 国网安徽省电力公司黄山供电公司 A kind of busbar small current neutral grounding warning system and method based on SCADA
CN109541380A (en) * 2019-01-18 2019-03-29 云南电网有限责任公司电力科学研究院 A kind of full compensating disturbance selection method of controllable voltage source earth current and device
CN110007198A (en) * 2019-05-16 2019-07-12 福州大学 A kind of novel singlephase earth fault starting method
CN110161355A (en) * 2019-04-30 2019-08-23 云南电网有限责任公司电力科学研究院 A kind of method for locating single-phase ground fault and device

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CN101042417A (en) * 2006-03-26 2007-09-26 吴昌德 Modelling method and route selecting method for single-phase grounding of low current neutral grounding system
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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102005741A (en) * 2010-10-29 2011-04-06 华北电力大学 Distribution network line single phase earthing fault diagnosis and isolation method and device
CN102435911A (en) * 2011-09-20 2012-05-02 江苏省电力公司宿迁供电公司 Automatic positioning system for single-phase earth fault of distribution line
CN102520314A (en) * 2011-11-23 2012-06-27 北京天能继保电力科技有限公司 Detection system and detection method for single-phase grounding fault line selection in small current grounding system
CN103424671A (en) * 2013-09-03 2013-12-04 刘天明 Low-current grounding fault manual discrimination line selection system of power system
CN104330709A (en) * 2014-11-28 2015-02-04 国家电网公司 Positioning method for single-phase earth fault sections of isolated neutral system
CN104330709B (en) * 2014-11-28 2017-03-01 国家电网公司 A kind of isolated neutral system singlephase earth fault Section Location
CN105223469A (en) * 2015-09-30 2016-01-06 国网浙江省电力公司绍兴供电公司 A kind of line-selected earthing device being applicable to intelligent substation
CN108008248A (en) * 2017-11-27 2018-05-08 国网安徽省电力公司黄山供电公司 A kind of busbar small current neutral grounding warning system and method based on SCADA
CN109541380A (en) * 2019-01-18 2019-03-29 云南电网有限责任公司电力科学研究院 A kind of full compensating disturbance selection method of controllable voltage source earth current and device
CN109541380B (en) * 2019-01-18 2020-04-24 云南电网有限责任公司电力科学研究院 Controllable voltage source grounding current full-compensation disturbance line selection method and device
CN110161355A (en) * 2019-04-30 2019-08-23 云南电网有限责任公司电力科学研究院 A kind of method for locating single-phase ground fault and device
CN110007198A (en) * 2019-05-16 2019-07-12 福州大学 A kind of novel singlephase earth fault starting method
CN110007198B (en) * 2019-05-16 2021-03-02 福州大学 Single-phase earth fault starting method

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