CN105356441A - Intelligent PT harmonic elimination and phase selection method and device - Google Patents
Intelligent PT harmonic elimination and phase selection method and device Download PDFInfo
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- CN105356441A CN105356441A CN201510789609.6A CN201510789609A CN105356441A CN 105356441 A CN105356441 A CN 105356441A CN 201510789609 A CN201510789609 A CN 201510789609A CN 105356441 A CN105356441 A CN 105356441A
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- 230000008030 elimination Effects 0.000 title claims abstract description 24
- 238000003379 elimination reaction Methods 0.000 title claims abstract description 24
- 238000010187 selection method Methods 0.000 title abstract 2
- 238000005070 sampling Methods 0.000 claims abstract description 12
- 238000000034 method Methods 0.000 claims description 10
- 230000003111 delayed effect Effects 0.000 claims description 6
- 230000007935 neutral effect Effects 0.000 description 9
- 230000001629 suppression Effects 0.000 description 5
- 230000001052 transient effect Effects 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/08—Limitation or suppression of earth fault currents, e.g. Petersen coil
Abstract
The invention provides an intelligent PT harmonic elimination and phase selection method and device. A three-phase five-pole voltage transformer PT is adopted to acquire voltage data in a power grid, and sampling of three-phase bus voltage and zero-sequence voltage is performed by a voltage sampling module when zero-sequence voltage occurs; sampling of zero-sequence current of all feeder lines is performed by a current sampling module, all sampling values are inputted to a single-chip microcomputer, the amplitude and the phase of all phases of voltage and zero-sequence voltage are calculated and judged by the single-chip microcomputer, fault phases and fault lines are selected, faults are classified into instantaneous faults or permanent faults according to duration of single-phase earth faults, and only alarming is actuated for protection as for the instantaneous single-phase earth faults so that reliability of power supply can be guaranteed; and tripping is actuated for protection apart from alarming as for the permanent single-phase earth faults so that safety of power supply can be guaranteed.
Description
Technical field
The present invention relates to power grid security field, especially harmonic elimination phase-selecting method and device, specifically a kind of neutral non-effective grounding electrical network eliminates resonance, to single phase ground fault Intelligent Recognition and guard method and device thereof.
Background technology
In neutral non-effective grounding electrical network, resonance and single-phase earthing are the major failure forms of operation of power networks, affect the safe operation of electrical network.
There is many energy-storage travelling wave tubes in electric power system, when system carries out operating or breaking down, transformer, instrument transformer etc. may cause ferro resonance containing capacitances in series in nonlinear inductance element and the system of iron-core element, form endanger safe operation of power system.In the non-direct ground system of isolated neutral, the ferro-resonance over-voltage that iron electromagnetic type voltage transformer causes is common, is the more a kind of internal overvoltage that causes the accident.This overvoltage gently then makes voltage transformer fuse failure, heavy then burn voltage transformer, even demolishs porcelain insulator and lightning arrester causes system shutdown.Series resonance phenomenon can be produced under certain power supply effect, cause in system, occurring serious resonance overvoltage.
Along with electrical network scale constantly expands, urban power grid cable, causes system single-phase earth fault electric current sharply to increase.Isolated neutral mode can not meet arc extinguishing and the superpotential requirement of restriction arc light already, the capacity of arc suppression coil is also required increasing, the jumbo arc suppression coil compensation device of transformer station's separate unit that some load is heavy can not meet the demands, need install two or multiple stage automatic Following-up Compensation Arc-decreasing Wires could meet compensation requirement at same bus.This not only increases the installation cost of arc suppression coil, and will increase installing space, brings inconvenience.And arc suppression coil is also limited in the effect of single phase ground fault: 1) arc suppression coil can reduce the probability of single-phase earthing overvoltage appearance but can not eliminate intermittency electric arc's earthing over-voltage; 2) number of times that arc light is restriked can be reduced, and the generation of ground arc can not be eradicated; 3) can only power frequency component in compensation of ground capacitance current, and harmonic component wherein can not be compensated; 4) can only idle component (capacitance current) in compensation of ground electric current, real component wherein can not be compensated; 5) can not judge high resistance earth fault and protect.
In the distribution of Neutral Grounding through Resistance in Electrical, because neutral resistor limits neutral point voltage, very high overvoltage can not be produced.Meanwhile, in ground path, flow through larger current in resistance property, ensure that zero-sequenceprotection accurately judges and excises faulty line fast.But the operational mode of resistive ground connection also has certain drawback: 1) when there is single-phase earthing, larger earth current may produce higher touch voltage and step voltage, threatens to equipment and the person, and interference is caused to around communication line; 2) one-phase ground protection action tripping operation, adds fault trip number of times and interruption duration, reduces power supply reliability; 3) for ensureing the continuity of power supply, the general network of low resistance grounding mode that adopts needs to have to turn power supply capacity to responsible consumer, makes operation more complicated; 4) can not judge high resistance earth fault and protect.
Summary of the invention
The object of the invention is the drawback existed for existing medium voltage network neutral grounding mode, a kind of intelligentized one-phase ground protection scheme is proposed, the time that the program continues according to single phase ground fault, be categorized as transient fault or permanent fault, to transient single-phase earth fault, a protection action, in warning, ensures power supply reliability; For permanent single phase earthing protection except also action of reporting to the police is in tripping operation, ensure Supply Security.
Technical scheme of the present invention is:
A kind of device of intelligent PT harmonic elimination phase selection, it is characterized in that it comprises three-phase five-pole voltage transformer PT, microcomputer control device WJCK and tripping operation case TZX, described three-phase five-pole voltage transformer PT is for gathering three-phase bus voltage in the electrical network in electrical network and residual voltage, its secondary voltage output is connected with the voltage sample module input of microcomputer control device WJCK, the current sampling signal input of microcomputer control device WJCK is connected with the secondary terminals of each bar feeder line zero sequence CT, gather feeder line zero sequence current signal, the K1 of microcomputer control device WJCK ... Kn output connects tripping operation case TZX, tripping operation case TZX output L1 ... Ln correspondence connects each bar feeder line, microcomputer control device WJCK controls tripping operation case TZX action, excision earth fault feeder line, another control output end of microcomputer control device WJCK connects the drive end of harmonic elimination solid-state relay XJ, is controlled the break-make in harmonic elimination loop by harmonic elimination solid-state relay XJ, realizes eliminating resonance.
Microcomputer control device WJCK of the present invention comprises: voltage sample module, current sample module, single-chip microcomputer and relay output control module; described voltage sample module and the signal output part of current sample module are by connecing the signal input part of single-chip microcomputer after sampling filter module; the control output end of single-chip microcomputer is connected with the input of relay output control module; single-chip microcomputer carries out computing and judgement to each voltage sample, current sample, is exported control the action of single-phase earth fault line selection trip protection and eliminate resonance by relay.
A kind of method of intelligent PT harmonic elimination phase selection, apply the device of intelligent PT phase selection, it comprises the following steps: adopt the voltage data in three-phase five-pole voltage transformer PT collection electrical network, when there is residual voltage, voltage sample module is to three-phase bus voltage and zero-sequence voltage samples; The zero-sequence current of current sample module to each bar feeder line is sampled, and all sampled values all input to single-chip microcomputer, and single-chip microcomputer calculates and judges amplitude and the phase place of each phase voltage and residual voltage, if in three-phase voltage: two phase voltages raise, a phase voltage reduces; Or a phase voltage raises, two-phase voltage reduces, and wherein 90 °, the delayed phase residual voltage phase place of arbitrary reduction phase voltage, then judge that sampling instant there occurs single phase ground fault, it is fault phase mutually that the voltage of 90 °, delayed residual voltage phase place reduces.
Method of the present invention also comprises the determination step of earth fault line: single-chip microcomputer calculates amplitude and the phase place of each bar feeder line zero-sequence current, get feeder current phase place and the residual voltage phase compare of first four of amplitude sequence, judge that the circuit of 90 °, delayed phase residual voltage phase place is as earth fault line.
To the protection step of single phase ground fault after method of the present invention also comprises phase selection route selection: when judging electrical network generation single phase ground fault, and and single phase ground fault time of origin last time interval is more than or equal to set point time, inquiry current failure whether with fault homophase and collinear last time;
If when previous fault has arbitrary not identical with fault phase last time with faulty line, then judge that last time fault is as instantaneity earth fault, keep last time Fault Phase Selection route selection to report to the police, and this fault is kainogenesis earth fault, record trouble moment, phase place, circuit reporting to the police;
If when previous fault and fault homophase collinear last time, then judge that this fault is as permanent earth fault, carry out reporting to the police and carry out trip operation to the ground path selected, excise faulty line.
Beneficial effect of the present invention:
The character (instantaneity or permanent) that the present invention is directed to different single phase ground faults takes different Preservation tactics, is namely of value to power supply reliability, is of value to Supply Security again.Compensate for the drawback that existing medium voltage network neutral grounding mode exists.
The three-phase five-pole voltage transformer of routine and microcomputer control device, the case that trips are combined by the present invention, and practical, observing and controlling is simple and reliable, and Intelligent single-phase ground protection can be provided reliably to eliminate ferro resonance again.
It is instantaneity or permanent that the present invention divides fault according to the duration that fault occurs, and reporting to the police, to permanent fault except reporting to the police, also carrying out route selection tripping operation to a transient fault route selection, excision faulty line.
Accompanying drawing explanation
Fig. 1 is differentiation of the present invention and guard method flow chart.
Fig. 2 is the electric structure principle chart of device of the present invention.
Fig. 3 is the theory diagram of microcomputer control device of the present invention.
In figure: QS: isolation trolley (or isolating switch); FU: high-tension fuse; PT: voltage transformer;
XJ: harmonic elimination solid-state relay; WJCK: microcomputer control device; TZX: tripping operation case;
Io1 ... Ion: feeder line zero-sequence current input; K1 ... Kn: microcomputer control device outputs end;
L1 ... Ln: end outputed by tripping operation case
Embodiment
Below in conjunction with drawings and Examples, the present invention is further illustrated.
A kind of device of intelligent PT harmonic elimination phase selection, it is characterized in that it comprises three-phase five-pole voltage transformer PT, microcomputer control device WJCK and tripping operation case TZX, described three-phase five-pole voltage transformer PT is for gathering three-phase bus voltage in the electrical network in electrical network and residual voltage, its secondary voltage output is connected with the voltage sample module input of microcomputer control device WJCK, the current sampling signal input of microcomputer control device WJCK is connected with the secondary terminals of each bar feeder line zero sequence CT, gather feeder line zero sequence current signal, the K1 of microcomputer control device WJCK ... Kn output connects tripping operation case TZX, tripping operation case TZX output L1 ... Ln correspondence connects each bar feeder line, microcomputer control device WJCK controls tripping operation case TZX action, excision earth fault feeder line, another control output end of microcomputer control device WJCK connects the drive end of harmonic elimination solid-state relay XJ, is controlled the break-make in harmonic elimination loop by harmonic elimination solid-state relay XJ, realizes eliminating resonance.
As shown in Figure 2, microcomputer control system as shown in Figure 3 for Integrated Protection System electricity structural principle of the present invention.Microcomputer control device detects three-phase voltage and the residual voltage of voltage transformer, and the zero-sequence current of this section of bus connection feeder line.Once judge system generation single phase ground fault, first fault phase and faulty line is selected, next judges whether it is identical fault phase and identical faulty line with single phase ground fault record last time, if there is a condition not meet, it is once then new fault, record the fault phase of this fault, faulty line and fault and the moment occurs, warning returns; If the two is all satisfied for foot, be then same fault, calculates trouble duration, if trouble duration is less than setting-up time, reports to the police and return; If be greater than setting-up time, be then judged to continuous earth fault, microcomputer control device drives the action of tripping operation case, excision earth fault line.
Microcomputer control device is by detecting three-phase voltage and the residual voltage of voltage transformer, accurately can judge whether system resonance occurs, once judge have resonance to occur, drive the solid-state relay being connected to voltage transformer open delta instantaneous closed at once, consume resonant energy and realize harmonic elimination.
Concrete example is as follows:
Example 1.
There is an instantaneous single phase ground fault of feeder line in device place bus, microcomputer control device is at once from the change of three-phase voltage, residual voltage and feeder current, select current single phase ground fault phase and faulty line, and inquiry is with or without continuous print failure logging, if do not have, be once then new fault, there is the moment in this fault phase of program record, faulty line and fault, being reported to the police and returning rejudges; Return after rejudging for several times, this failure vanishes, its duration is less than permanent fault set point, then device judges that this fault is as instantaneity earth fault, and protection is only done phase selection route selection and reported to the police.
Example 2.
There is a permanent single phase ground fault of feeder line in device place bus, microcomputer control device is at once from the change of three-phase voltage, residual voltage and feeder current, select current single phase ground fault phase and faulty line, and inquiry is with or without continuous print failure logging, if do not have, be once then new fault, there is the moment in this fault phase of program record, faulty line and fault, being reported to the police and returning rejudges; Return for several times after rejudging, this fault still exists, and its duration is greater than permanent fault set point; then device judges that this fault is as permanent earth fault; protection is not only done phase selection route selection and is reported to the police, and what also drive tripping operation case correspondence to select faulty line outputs end action, excision earth fault line.
Example 3.
Device place bus is due to voltage disturbances such as single phase ground faults, excitation voltage instrument transformer ferro resonance, microcomputer control device is at once from the change of three-phase voltage, residual voltage and frequency, judge that resonance occurs, and drive the solid-state relay being connected to voltage transformer open delta instantaneous closed, consume resonant energy and realize harmonic elimination.
The part that the present invention does not relate to prior art that maybe can adopt all same as the prior art is realized.
Claims (5)
1. the device of an intelligent PT harmonic elimination phase selection, it is characterized in that it comprises three-phase five-pole voltage transformer PT, microcomputer control device WJCK and tripping operation case TZX, described three-phase five-pole voltage transformer PT is for gathering three-phase bus voltage in the electrical network in electrical network and residual voltage, its secondary voltage output is connected with the voltage sample module input of microcomputer control device WJCK, the current sampling signal input of microcomputer control device WJCK is connected with the secondary terminals of each bar feeder line zero sequence CT, gather feeder line zero sequence current signal, the K1 of microcomputer control device WJCK ... Kn output connects tripping operation case TZX, tripping operation case TZX output L1 ... Ln correspondence connects each bar feeder line, microcomputer control device WJCK controls tripping operation case TZX action, excision earth fault feeder line, another control output end of microcomputer control device WJCK connects the drive end of harmonic elimination solid-state relay XJ, is controlled the break-make in harmonic elimination loop by harmonic elimination solid-state relay XJ, realizes eliminating resonance.
2. the device of intelligent PT harmonic elimination phase selection according to claim 1, it is characterized in that microcomputer control device WJCK comprises: voltage sample module, current sample module, single-chip microcomputer and relay output control module, described voltage sample module and the signal output part of current sample module are by connecing the signal input part of single-chip microcomputer after sampling filter module, the control output end of single-chip microcomputer is connected with the input of relay output control module, single-chip microcomputer is to each voltage sample, current sample carries out computing and judgement, exported by relay and control the action of single-phase earth fault line selection trip protection and eliminate resonance.
3. the method for an intelligent PT harmonic elimination phase selection, application rights requires the device of the intelligent PT phase selection described in 2, it is characterized in that it comprises the following steps: adopt the voltage data in three-phase five-pole voltage transformer PT collection electrical network, when there is residual voltage, voltage sample module is to three-phase bus voltage and zero-sequence voltage samples; The zero-sequence current of current sample module to each bar feeder line is sampled, and all sampled values all input to single-chip microcomputer, and single-chip microcomputer calculates and judges amplitude and the phase place of each phase voltage and residual voltage, if in three-phase voltage: two phase voltages raise, a phase voltage reduces; Or a phase voltage raises, two-phase voltage reduces, and wherein 90 °, the delayed phase residual voltage phase place of arbitrary reduction phase voltage, then judge that sampling instant there occurs single phase ground fault, it is fault phase mutually that the voltage of 90 °, delayed residual voltage phase place reduces.
4. the method for intelligent PT harmonic elimination phase selection according to claim 3, it is characterized in that it also comprises the determination step of earth fault line: single-chip microcomputer calculates amplitude and the phase place of each bar feeder line zero-sequence current, get feeder current phase place and the residual voltage phase compare of first four of amplitude sequence, judge that the circuit of 90 °, delayed phase residual voltage phase place is as earth fault line.
5. the method for intelligent PT harmonic elimination phase selection according to claim 4, it is characterized in that it also comprise phase selection route selection after protection step to single phase ground fault: when judging electrical network generation single phase ground fault, and and single phase ground fault time of origin last time interval is more than or equal to set point time, inquiry current failure whether with fault homophase and collinear last time;
If when previous fault has arbitrary not identical with fault phase last time with faulty line, then judge that last time fault is as instantaneity earth fault, keep last time Fault Phase Selection route selection to report to the police, and this fault is kainogenesis earth fault, record trouble moment, phase place, circuit reporting to the police;
If when previous fault and fault homophase collinear last time, then judge that this fault is as permanent earth fault, carry out reporting to the police and carry out trip operation to the ground path selected, excise faulty line.
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| CN106405191A (en) * | 2016-06-30 | 2017-02-15 | 国网浙江建德市供电公司 | Zero-sequence current sampling circuit capable of AC grounding precise judgment, and judgment method thereof |
| CN106849076A (en) * | 2017-04-14 | 2017-06-13 | 国网宁夏电力公司银川供电公司 | Earth fault alignment alarm type mobile substation |
| CN108132417A (en) * | 2017-11-24 | 2018-06-08 | 国网北京市电力公司 | Method for locating single-phase ground fault and device |
| CN108196214A (en) * | 2017-12-12 | 2018-06-22 | 神华集团有限责任公司 | Feeder line zero sequence current mutual inductor CT polarity check methods and device |
| CN108448562A (en) * | 2018-05-25 | 2018-08-24 | 云南电网有限责任公司电力科学研究院 | A kind of full compensation method of electric current based on singlephase earth fault and system |
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| CN110568312A (en) * | 2019-09-11 | 2019-12-13 | 中南大学 | Phase current distortion-based single-phase earth fault line selection method for neutral point ungrounded system |
| CN112485596A (en) * | 2020-11-30 | 2021-03-12 | 云南电网有限责任公司电力科学研究院 | Power distribution network ground fault detection device and method |
| CN113671412A (en) * | 2021-09-10 | 2021-11-19 | 国网安徽省电力有限公司检修分公司 | Low-current grounding line selection device |
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| CN108196214A (en) * | 2017-12-12 | 2018-06-22 | 神华集团有限责任公司 | Feeder line zero sequence current mutual inductor CT polarity check methods and device |
| CN108448562A (en) * | 2018-05-25 | 2018-08-24 | 云南电网有限责任公司电力科学研究院 | A kind of full compensation method of electric current based on singlephase earth fault and system |
| CN110247383A (en) * | 2019-04-30 | 2019-09-17 | 云南电网有限责任公司电力科学研究院 | The removing method and device of ferromagnetic resonance in a kind of active compensation system |
| CN110568312A (en) * | 2019-09-11 | 2019-12-13 | 中南大学 | Phase current distortion-based single-phase earth fault line selection method for neutral point ungrounded system |
| CN112485596B (en) * | 2020-11-30 | 2022-06-07 | 云南电网有限责任公司电力科学研究院 | Power distribution network ground fault detection device and method |
| CN112485596A (en) * | 2020-11-30 | 2021-03-12 | 云南电网有限责任公司电力科学研究院 | Power distribution network ground fault detection device and method |
| CN113671412A (en) * | 2021-09-10 | 2021-11-19 | 国网安徽省电力有限公司检修分公司 | Low-current grounding line selection device |
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