CN106229960B - Detect the ferromagnetic resonance harmonic elimination method of zero-sequence current pulse amplitude uniformity - Google Patents
Detect the ferromagnetic resonance harmonic elimination method of zero-sequence current pulse amplitude uniformity Download PDFInfo
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- CN106229960B CN106229960B CN201610680343.6A CN201610680343A CN106229960B CN 106229960 B CN106229960 B CN 106229960B CN 201610680343 A CN201610680343 A CN 201610680343A CN 106229960 B CN106229960 B CN 106229960B
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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
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/20—Instruments transformers
- H01F38/22—Instruments transformers for single phase ac
- H01F38/28—Current transformers
- H01F38/32—Circuit arrangements
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Abstract
The present invention be on it is a kind of detect zero-sequence current pulse amplitude uniformity ferromagnetic resonance harmonic elimination method, wherein, the described method includes judge whether current transformer detects the zero-sequence current between electromagnetic potential transformer neutral point and ground；When detecting that the zero-sequence current is more than default zero-sequence current, the pulse amplitude uniformity for the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration is calculated；According to the pulse amplitude uniformity of the zero-sequence current, judge whether the electromagnetic potential transformer occurs ferromagnetic resonance；When ferromagnetic resonance occurs for the electromagnetic potential transformer, control is closed with the first controlling switch that harmonic elimination resistance is connected in series, and harmonic elimination processing is carried out to the electromagnetic potential transformer.The device provided through this embodiment can accurately, quickly eliminate ferromagnetic resonance, and improve the harmonic elimination efficiency of ferromagnetic resonance.
Description
Technical field
The present invention relates to power system security Prevention Technique field, more particularly to a kind of detection zero-sequence current pulse amplitude one
The ferromagnetic resonance harmonic elimination method of cause property.
Background technology
In the power distribution network of 66kV and below 66kV, generally use system neutral is earth-free and neutral point through small resistor or
The non-effectively earthed system of grounding through arc, the electromagnetic potential transformer of monitoring insulation against ground is connected on system busbar
(Potential Transformer, PT).Because lightning stroke, single-phase earthing, the operation of conjunction aircraft carrier line, load acute variation occur for circuit
And the transient state impact that produces of the reason such as secondary voltage load switching may excite the excitation reactance of electromagnetic potential transformer with
There is ferromagnetic resonance between system direct-to-ground capacitance.Electromagnetic potential transformer frequent breakage, fusing caused by ferromagnetic resonance in recent years
The device problem that frequently fuses still annoyings equipment operation maintenance unit, and such isolated neutral system or neutral point are through small resistor
Or the non-effectively earthed system (part for accidentally departing from small resistor or grounding through arc) of grounding through arc be easy to cause and sets
Standby frequent breakage, increases operation expense.
At present, the protection method of the ferromagnetic resonance in correlation technique for appearance mainly uses：In electromagnetic potential mutual inductance
Neutral point of device installs resonance eliminator additional, alternatively, using installed additional in electromagnetic potential transformer residual voltage circuit damping resistance,
By installing microcomputer secondary resonance elimination device additional and detecting residual voltage and every phase voltage waveform etc..Wherein, in electromagnetic potential mutual inductance
Neutral point of device installs resonance eliminator additional, i.e., connects resonance eliminator in electromagnetic potential transformer successively neutral point, pass through resonance eliminator pair
The ferromagnetic resonance of generation carries out harmonic elimination.
But install the mode of resonance eliminator additional in central point of electromagnetic potential transformer, although can be in anti-locking system
The three-phase voltage easily produced over the ground between ferromagnetic resonance, it is but poor for industrial frequency resonance harmonic elimination effect caused by broken string, and easily
The voltage of electromagnetic potential transformer neutral point is brought to raise, the bad phenomenon such as electromagnetic potential transformer tail end insulation breakdown,
Cause resonance eliminator ineffective；Installing damping resistance additional can be because damping resistance fever influences harmonic elimination effect；Disappear using microcomputer is secondary
Humorous device device, because the method for detection residual voltage and three-phase voltage waveform is difficult to differentiate between industrial frequency resonance, there are measure loop and disappears
Humorous circuit shares or need to detect three-phase voltage problem.
Therefore, by using above-mentioned existing harmonic elimination mode, harmonic elimination time and increase harmonic elimination cost can not only be extended, and
And meeting extreme influence harmonic elimination efficiency, equipment frequent breakage is caused, serious threat is caused to the safe and stable operation of power grid and equipment.
The content of the invention
To overcome problem present in correlation technique, the present invention provides a kind of detection zero-sequence current pulse amplitude uniformity
Ferromagnetic resonance harmonic elimination method.
First aspect according to embodiments of the present invention, there is provided a kind of to detect the ferromagnetic humorous of zero-sequence current pulse amplitude uniformity
Shake harmonic elimination method, including：
Judge whether current transformer detects the zero-sequence current between electromagnetic potential transformer neutral point and ground；
When detecting that the zero-sequence current is more than default zero-sequence current, calculate and reach default arteries and veins in the first preset duration
The pulse amplitude uniformity of the zero-sequence current of amplitude is rushed, wherein, the predetermined pulse amplitude is more than the default zero-sequence current
Pulse amplitude；
According to the pulse amplitude uniformity of the zero-sequence current, it is ferromagnetic to judge whether the electromagnetic potential transformer occurs
Resonance；
When ferromagnetic resonance occurs for the electromagnetic potential transformer, control and harmonic elimination resistance is connected in series first controls
Switch closure, harmonic elimination processing is carried out to the electromagnetic potential transformer.
Preferably, the pulse amplitude one for calculating the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration
Cause property, including：
When detecting that the zero-sequence current is more than default zero-sequence current, start the first timer, start timing；
Zero-sequence current in first preset duration of the timing is gathered by current transformer；
Search the zero-sequence current that pulse amplitude is greater than or equal to predetermined pulse amplitude；
Calculate the pulse amplitude uniformity that pulse amplitude is greater than or equal to the adjacent zero-sequence current of predetermined pulse amplitude.
Preferably, the pulse amplitude for calculating pulse amplitude and being greater than or equal to the adjacent zero-sequence current of predetermined pulse amplitude
Uniformity, including：
Calculate the difference and average value of the pulse amplitude absolute value of adjacent zero-sequence current；
According to the difference and average value, the pulse amplitude uniformity of adjacent zero-sequence current, the pulse amplitude are determined
Uniformity is the difference and the percentage of the toaverage ratio.
Preferably, first preset duration is 80ms, and the predetermined pulse amplitude is 100-500mA.
Preferably, judge whether the electromagnetic potential transformer occurs ferromagnetic resonance, including：
Judge whether the pulse amplitude uniformity of the zero-sequence current is less than 20%；
When the pulse amplitude uniformity of the zero-sequence current is less than 20%, determine that the electromagnetic potential transformer occurs
Ferromagnetic resonance.
Preferably, when control is closed with the first controlling switch that harmonic elimination resistance is connected in series, the method further includes：
Start the second timer, start timing；
Judge in the second preset duration, whether the pulse amplitude of the zero-sequence current is reduced to the default zero-sequence current
Pulse amplitude below；
When the zero-sequence current is not reduced to below the pulse amplitude of the default zero-sequence current, control first control
System switches off, and the second controlling switch that control is electrically connected with the open delta circuit of the electromagnetic potential transformer is closed
Close, so that the open delta circuit short circuit of the electromagnetic potential transformer, eliminates the ferromagnetic of the electromagnetic potential transformer
Resonance.
Preferably, second preset duration is 50ms.
Preferably, when the second controlling switch that control is electrically connected with the open delta circuit of the electromagnetic potential transformer
During closure, the method further includes：
Start the 3rd timer, start timing；
The pulse amplitude of zero-sequence current described in real-time judge whether be reduced to the pulse amplitude of the default zero-sequence current with
Under；
When the pulse amplitude of the zero-sequence current is not reduced to below the pulse amplitude of the default zero-sequence current and described
When 3rd duration of timing reaches three preset durations, second controlling switch is controlled to disconnect；
When controlling the second controlling switch turn-off time to reach four preset durations, second control is controlled again
Switch closure, until the pulse amplitude of the zero-sequence current is down to below the pulse amplitude of the default zero-sequence current.
Preferably, the 3rd preset duration is 200ms, and the 4th preset duration is 20-60ms.
Preferably, the pulse amplitude of the default zero-sequence current is 10-100mA.
The technical solution that the embodiment of the present invention provides can include the following benefits：
The embodiment of the present invention provides a kind of ferromagnetic resonance harmonic elimination method for detecting zero-sequence current pulse amplitude uniformity, described
Method includes judging whether current transformer detects the zero-sequence current between electromagnetic potential transformer neutral point and ground；Work as inspection
When measuring the zero-sequence current more than default zero-sequence current, the zero sequence for reaching predetermined pulse amplitude in the first preset duration is calculated
The pulse amplitude uniformity of electric current；According to the pulse amplitude uniformity of the zero-sequence current, the electromagnetic potential mutual inductance is judged
Whether device occurs ferromagnetic resonance；When ferromagnetic resonance occurs for the electromagnetic potential transformer, company of connecting with harmonic elimination resistance is controlled
The the first controlling switch closure connect, harmonic elimination processing is carried out to the electromagnetic potential transformer.
The embodiment of the present invention can determine whether the electromagnetic potential by detecting zero-sequence current, according to the size of zero-sequence current
Whether mutual inductor occurs ferromagnetic resonance, in the event of ferromagnetic resonance, then the first controlling switch can be controlled to close, make harmonic elimination resistance
Series loop is formed with open delta circuit, by the primary circuit damping of harmonic elimination resistance increase electromagnetic potential transformer, so that soon
Speed eliminates the ferromagnetic resonance of electromagnetic potential transformer, since harmonic elimination resistance is connected directly between on open delta circuit, Neng Gouzhun
Really, ferromagnetic resonance is quickly eliminated, so as to effectively improve the harmonic elimination efficiency of ferromagnetic resonance, moreover, this is simple in structure, is effectively reduced existing
There is the cost of the complicated microcomputer secondary resonance elimination device that power grid uses in technology.
In addition, in the present invention is implemented, by being connected in parallel one second control on harmonic elimination resistance and the first controlling switch
Switch, once the quick harmonic elimination of ferromagnetic resonance that can not be quickly produced by the harmonic elimination resistance to the electromagnetic potential transformer
When, by resonance judgment module second controlling switch can be controlled to close, return the open delta of electromagnetic potential transformer
Road forms short circuit, equivalent to the energized circuit short circuit the electromagnetic potential transformer of resonant tank, so as to electromagnetic potential
The ferromagnetic resonance that mutual inductor produces quickly eliminates, and can further improve the elimination efficiency of ferromagnetic resonance, greatly shorten existing skill
The time that ferromagnetic resonance eliminates in art.
It should be appreciated that the general description and following detailed description of the above are only exemplary and explanatory, not
Can the limitation present invention.
Brief description of the drawings
Attached drawing herein is merged in specification and forms the part of this specification, shows the implementation for meeting the present invention
Example, and for explaining the principle of the present invention together with specification.
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
There is attached drawing needed in technology description to be briefly described, it should be apparent that, for those of ordinary skill in the art
Speech, without having to pay creative labor, can also obtain other attached drawings according to these attached drawings.
Fig. 1 is a kind of structure diagram of ferromagnetic resonance harmonic elimination apparatus provided in an embodiment of the present invention；
Fig. 2 is a kind of application scenarios schematic diagram of ferromagnetic resonance harmonic elimination apparatus provided in an embodiment of the present invention；
Fig. 3 is a kind of flow diagram of ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention；
The detailed process that Fig. 4 is a kind of step S102 of ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention is illustrated
Figure；
The detailed process that Fig. 5 is a kind of step S1024 of ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention is illustrated
Figure；
The detailed process that Fig. 6 is a kind of step S103 of ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention is illustrated
Figure；
Fig. 7 is the flow diagram of another ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention；
Fig. 8 is the detailed process schematic diagram of another ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention.
Embodiment
Here exemplary embodiment will be illustrated in detail, its example is illustrated in the accompanying drawings.Following description is related to
During attached drawing, unless otherwise indicated, the same numbers in different attached drawings represent the same or similar key element.Following exemplary embodiment
Described in embodiment do not represent and the consistent all embodiments of the present invention.On the contrary, they be only with it is such as appended
The example of the consistent apparatus and method of some aspects being described in detail in claims, of the invention.
Fig. 1 is a kind of structure diagram of ferromagnetic resonance harmonic elimination apparatus according to an exemplary embodiment.Such as 1 institute
Show, which can include power module 11, resonance judgment module 12, harmonic elimination module and current transformer 16 (CT, Current
Tranfer)。
In embodiment disclosed by the invention, power module 11 is respectively electrically connected to the resonance judgment module 12 and harmonic elimination
Module, so that power supply is provided for resonance judgment module 12 and harmonic elimination module, and power module 11 can be directly connected to alternating current, it is described
Resonance judgment module 12 can be CPU (Central Processing Unit, central processing unit) or PLC (Programmable
Logic Controller, programmable logic controller (PLC)), the resonance judgment module 12 is electrically connected to the harmonic elimination module, uses
Harmonic elimination is carried out in controlling the harmonic elimination module；The current transformer 16 is used to be electrically connected to the electromagnetic potential transformer 17
Connecting wire between neutral point and ground, so as to measure zero-sequence current (i.e. electromagnetic potential transformer three by current transformer 16
The sum of phase exciting current).
In order to realize the ferromagnetic resonance to electromagnetic potential transformer in power distribution network 17, which disappears including at least one
Humorous 13 and first controlling switch 14 of resistance, the both ends of the harmonic elimination resistance 13 are connected to the electromagnetic potential transformer 17
Open delta circuit both ends, first controlling switch 14 be series at the harmonic elimination resistance 13 and open delta circuit it
Between, i.e., open delta circuit, 13 and first controlling switch 14 of harmonic elimination resistance form series loop, and pass through the first controlling switch 14
Break-make make open delta circuit, 13 and first controlling switch 14 of harmonic elimination resistance formed closure or disconnect series loop.And
In embodiment disclosed by the invention, the resonance judgment module 12 is electrically connected to the first controlling switch 14, so as to be judged by resonance
Module 12 controls the break-make of first controlling switch 14.
Wherein, in embodiment disclosed by the invention, the Standard resistance range of the harmonic elimination resistance 13 is 0.5-10 Ω, preferably
For 1 Ω, the both ends in the open delta circuit of electromagnetic potential transformer 17 are accessed by harmonic elimination resistance 13, so as to pass through harmonic elimination electricity
The resistance value of resistance 13 increases electromagnetic potential transformer loop damping successively, so as to eliminate the ferromagnetic of electromagnetic potential transformer generation
Resonance.Moreover, first controlling switch 14 generally uses electronic power switch or relay switch, and power module 11 is distinguished
The first controlling switch 14 and the second controlling switch 15 are electrically connected, so as to control the first controlling switch 14 by resonance judgment module 12
Harmonic elimination resistance 13 is set directly with open delta circuit in series, to make it to the quick harmonic elimination of electromagnetic potential transformer.It is being embodied
During, the resistance value of harmonic elimination resistance 13 is the smaller the better, for example, when the resistance value of harmonic elimination resistance 13 is 0.5 Ω, can be at utmost
Increase the primary circuit damping of electromagnetic potential transformer 17, the ferromagnetic resonance of electromagnetic potential transformer 17 is quickly eliminated.
In ferromagnetic resonance harmonic elimination apparatus provided in an embodiment of the present invention, when can not quickly eliminate electricity using harmonic elimination resistance 13
During the ferromagnetic resonance of electromagnetic type voltage transformer 17, the harmonic elimination module in ferromagnetic resonance harmonic elimination apparatus provided in an embodiment of the present invention is also
Including the second controlling switch 15,13 and first controlling switch 14 of second controlling switch 15 and the harmonic elimination resistance is in parallel to be set
Put, and the second controlling switch 15 is respectively electrically connected to the both ends in the open delta circuit, by controlling the second controlling switch 15
Break-make make open delta circuit and second control open extension 15 formed series loops.So as to when harmonic elimination resistance 13 can not be to electromagnetism
The ferromagnetic resonance that formula voltage transformer produces can put into second controlling switch 15 when quickly eliminating, make open delta circuit with
The series connection of second controlling switch 15 forms short circuit, and then the ferromagnetic resonance of electromagnetic potential transformer is eliminated.
In addition, in embodiment disclosed by the invention, which can also include timer (being not shown), described
Timer is electrically connected with resonance judgment module 12 and harmonic elimination module respectively, and operating voltage is provided for timer by power module 11,
Accurately the first controlling switch 14 and the second controlling switch 15 is controlled to close according to the timing time of timer by resonance judgment module 12
Close, so as to achieve the purpose that to carry out accurate harmonic elimination to the ferromagnetic resonance of electromagnetic potential transformer 17, effectively improve harmonic elimination efficiency.
Meanwhile in embodiment disclosed by the invention, the timely of different periods, and the timer can be carried out by a timer
Number can be arranged as required to it is multiple, by multiple timers to different periods Split Time, so as to effectively improve to the time
Accurate control.
Fig. 2 shows ferromagnetic resonance harmonic elimination apparatus application scenarios schematic diagram in power distribution network provided in an embodiment of the present invention,
As shown in Fig. 2, ferromagnetic resonance harmonic elimination apparatus provided in an embodiment of the present invention includes power module 11, resonance judgment module 12, disappears
Humorous resistance 13, the first controlling switch 14, the second controlling switch 15 and current transformer 16, the power module 11 are electrically connected
To the resonance judgment module 12 and harmonic elimination module, the current transformer 16 is also electrically connected to resonance judgment module 12, electric current
Mutual inductor 16 is used to send the zero-sequence current of collection to resonance judgment module 12.
Wherein, in power distribution network, three-phase voltage (E1, E2, E3) is respectively electrically connected to electromagnetic potential transformer 17, and electricity
Electromagnetic type voltage transformer 17 is connected in parallel a three phase capacitance (C1, C2, C3), and three phase capacitance is respectively electrically connected to three-phase voltage.
The electromagnetic potential transformer 17 includes an open delta circuit, and it is mutual that the current transformer 16 is electrically connected to electromagnetic potential
Connecting wire between the neutral point and ground of sensor 17, for gathering the zero-sequence current of electromagnetic potential transformer 17；Institute
State 13 and first controlling switch 14 of harmonic elimination resistance to concatenate and be series at the both ends in open delta circuit, second controlling switch
15 are arranged in parallel with 13 and first controlling switch 14 of harmonic elimination resistance, and second controlling switch 15 is concatenated to open delta circuit
Both ends.
In specific implementation process, in the case that EMR electromagnetic resonance does not occur for electromagnetic potential transformer 17, first control
System switch 14 and the second controlling switch 15 are in, when EMR electromagnetic resonance occurs for electromagnetic potential transformer 17, judging mould by resonance
Block 12 controls the first controlling switch 14 to close, and open delta circuit and harmonic elimination resistance 13 is formed series loop, passes through harmonic elimination electricity
The primary circuit damping of the increase electromagnetic potential transformer 17 of resistance 13, so as to eliminate ferromagnetic resonance；When the first controlling switch 14 is closed
Closing preset time (such as 50ms), for ferromagnetic resonance still without elimination, resonance judgment module 12 controls the second controlling switch 15 to close afterwards
Close, while the first controlling switch 14 is opened, open delta circuit is formed series loop with the second controlling switch 15, due to the
After two controlling switches 15 and open delta circuit in series, 15 shape same root conducting wire of the second controlling switch, i.e. open delta circuit
Direct short-circuit, so as to eliminate the ferromagnetic resonance of electromagnetic potential transformer 17.
Using ferromagnetic resonance harmonic elimination apparatus provided in an embodiment of the present invention, for resonance judgment module and disappeared by power module
Humorous module provides supply voltage, and the zero-sequence current in electromagnetic potential transformer open delta circuit is detected by current transformer,
And the zero-sequence current is sent to resonance judgment module, the resonance judgment module and can determine whether according to the size of zero-sequence current
Whether the electromagnetic potential transformer occurs ferromagnetic resonance, in the event of ferromagnetic resonance, then can control the first controlling switch
Closure, makes harmonic elimination resistance form series loop with open delta circuit, by harmonic elimination resistance increase electromagnetic potential transformer once
Loop damping, so that the ferromagnetic resonance of electromagnetic potential transformer is quickly eliminated, since harmonic elimination resistance is connected directly between opening three
On angular convolution road, can accurately, quickly eliminate ferromagnetic resonance, so that the harmonic elimination efficiency of ferromagnetic resonance is effectively improved, moreover, the structure
Simply, the cost that enterprise in the prior art uses complex appts is effectively reduced.
In addition, in the present invention is implemented, by being connected in parallel one second control on harmonic elimination resistance and the first controlling switch
Switch, once the quick harmonic elimination of ferromagnetic resonance that can not be quickly produced by the harmonic elimination resistance to the electromagnetic potential transformer
When, by resonance judgment module second controlling switch can be controlled to close, return the open delta of electromagnetic potential transformer
Road forms short circuit, so that the ferromagnetic resonance produced to electromagnetic potential transformer quickly eliminates, can further improve ferromagnetic humorous
The elimination efficiency shaken, greatly shortens the time that ferromagnetic resonance eliminates in the prior art.
Above is it is described in detail for the embodiment of device provided by the invention, in embodiment disclosed by the invention
In, the way of example of harmonic elimination method when additionally providing to ferromagnetic resonance progress harmonic elimination processing, referring specifically to real in detailed below
Apply the description of example.
Fig. 3 shows a kind of flow diagram of ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention.It is of the invention public
The ferromagnetic resonance harmonic elimination method opened is applied in the resonance judgment module 12 in ferromagnetic resonance harmonic elimination apparatus, judges mould by resonance
Block 12 judges whether electromagnetic potential transformer 17 occurs ferromagnetic resonance according to the zero-sequence current that current transformer 16 gathers, and leads to
Cross control the first controlling switch 14, the break-make of the second controlling switch 15 to the ferromagnetic resonance that electromagnetic potential transformer 17 produces into
The processing of row harmonic elimination.As shown in figure 3, this method may include steps of.
In step S101, judge whether current transformer is detected between electromagnetic potential transformer neutral point and ground
Zero-sequence current.Otherwise, terminate.
Since when not ferromagnetic resonance occurs for electromagnetic potential transformer, the open delta of electromagnetic potential transformer returns
Road will not then produce sensing electric current, therefore can be detected by current transformer between electromagnetic potential transformer neutral point and ground
The size of zero-sequence current.
When detecting that zero-sequence current is more than default zero-sequence current, in step s 102, calculate in the first preset duration
Reach the pulse amplitude uniformity of the zero-sequence current of predetermined pulse amplitude.
In embodiment disclosed by the invention, under normal circumstances, when electromagnetic potential transformer does not produce ferromagnetic resonance, still
Zero-sequence current is had, simply the pulse amplitude of zero-sequence current is relatively low at this time, generally 0-0.2mA.When detecting zero-sequence current, need
Will be by judging whether zero-sequence current exceeds the pulse amplitude of default zero-sequence current, and the arteries and veins of zero-sequence current within a certain period of time
Rushing amplitude uniformity could judge whether electromagnetic potential transformer occurs ferromagnetic resonance.Wherein, when detecting zero-sequence current
More than default zero-sequence current pulse amplitude 10-100mA (and the pulse amplitude of default zero-sequence current is preferably 60mA) when can
To start timer, the pulse amplitude uniformity for the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration is calculated.
In specific implementation process, first preset duration could be provided as 80ms, wherein, the predetermined pulse amplitude is more than described
The pulse amplitude of default zero-sequence current, the predetermined pulse amplitude can be set as 100-500mA, and predetermined pulse amplitude is preferred
For 200mA, so as to easy to finding ferromagnetic resonance in time and eliminated.In implementation process, described first it is default when
Long and predetermined pulse amplitude is not limited to above is the numerical value that embodiment proposes, can according to electromagnetic potential transformer and
The resistance value of harmonic elimination resistance is determined, is no longer elaborated herein.
The detailed process schematic diagram of step S102 provided in an embodiment of the present invention can be found in Fig. 4.As shown in figure 4, step
S102 specifically comprises the following steps：
When detecting that the zero-sequence current is more than 10-100mA, in step S1021, start the first timer, start
Timing.
In embodiment disclosed by the invention, it is necessary to by judging that the pulse amplitude of the zero-sequence current in certain time is consistent
Property, and then judge whether electromagnetic current transducer occurs EMR electromagnetic resonance, and unite since zero-sequence current is more than 10-100mA
The pulse amplitude of zero-sequence current is counted, therefore, when detecting zero-sequence current, when being preset by starting the first timer progress first
Long timing, in implementation process, can carry out timing by way of countdown.
In step S1022, the zero-sequence current in the first preset duration of the timing is gathered by current transformer.
When timing starts, then zero-sequence current all in the first preset duration is gathered by current transformer, and according to note
The pulse amplitude of all zero-sequence currents of record, easy to step S1023 processing.Wherein, first preset duration is 80ms, and
The time of first preset duration might not be arranged to 80ms, the ferromagnetic resonance that can also be produced according to electromagnetic potential transformer
Cycle of pulse current calculated, can be the multiple in the cycle of the pulse current of ferromagnetic resonance.
When collecting zero-sequence currents all in the first preset duration, in step S1023, search pulse amplitude and be more than
Or the zero-sequence current equal to predetermined pulse amplitude.
In embodiment disclosed by the invention, the predetermined pulse amplitude is value set in advance, and the predetermined pulse
Value of the amplitude for startup ferromagnetic resonance harmonic elimination apparatus there may be ferromagnetic resonance, in specific implementation process, the predetermined pulse
Amplitude is 100-500mA, i.e., only the pulse amplitude of zero-sequence current is greater than or equal to ability in the case of the predetermined pulse amplitude
Ferromagnetic resonance may occur, therefore it may only be necessary to be greater than or equal to the zero-sequence current of predetermined pulse amplitude in finding step S1022.
When find pulse amplitude be greater than or equal to predetermined pulse amplitude zero-sequence current when, in step S1024, calculate
Pulse amplitude is greater than or equal to the pulse amplitude uniformity of the adjacent zero-sequence current of predetermined pulse amplitude.
According to the zero-sequence current determined in step S1023, the pulse amplitude for calculating zero-sequence current in step S1023 is consistent
Property.
In embodiment disclosed by the invention, the detailed process of step S102 is not limited to the step shown in above-described embodiment
The limitation of rapid sequencing, can first calculate the pulse amplitude of all zero-sequence currents, further according to the pulse width of zero-sequence current
Value filters out satisfactory zero sequence pulse current, then calculates the pulse amplitude uniformity of adjacent zero-sequence current.
By the way of above-described embodiment, data processing amount can be reduced to greatest extent, so as to accelerate to suitable zero sequence
The screening of electric current, so as to reduce processing processing time, quickly judges whether electromagnetic potential transformer occurs EMR electromagnetic resonance, and
Harmonic elimination is carried out by harmonic elimination resistance, so as to further improve harmonic elimination efficiency.
In addition, in embodiment disclosed by the invention, Fig. 5 shows that step S1024's provided in an embodiment of the present invention is detailed
Thin flow diagram, as shown in figure 5, step S1024 is further included：
In step S10241, the difference and average value of the pulse amplitude absolute value of adjacent zero-sequence current are calculated.
, can be random when getting the zero-sequence current of all in step S1023 more than predetermined pulse amplitude 100-500mA
Two adjacent zero-sequence currents are searched, and calculate the pulse amplitude between two adjacent zero-sequence currents, it is absolute according to pulse amplitude
Value calculates the absolute value differences and average value between two adjacent zero-sequence currents；Either, it is all according to what is found
Zero-sequence current, searches all two adjacent zero-sequence currents, and calculate the pulse amplitude absolute value of two adjacent zero-sequence currents
Difference and average value.
In step S10242, according to the difference and average value, determine that the pulse amplitude of adjacent zero-sequence current is consistent
Property.
In embodiments of the present invention, the pulse amplitude uniformity is the difference and the percentage of the toaverage ratio
Than specifically, can be calculated according to the difference and average value of the pulse amplitude absolute value of random two adjacent zero-sequence currents
The ratio of the difference and average value, and it is converted into pulse amplitude uniformity of the percentage as current zero-sequence current.Either,
The pulse amplitude uniformity of multigroup adjacent zero-sequence current is calculated respectively, then asks for its average value respectively, is in the application
The pulse amplitude uniformity for the adjacent zero-sequence current that step S102 is pointed out.
When getting the pulse amplitude uniformity for the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration,
In step S103, judge whether the electromagnetic potential transformer occurs ferromagnetic resonance.Otherwise, step S101 is continued to execute.
In embodiments of the present invention, by drawing the pulse width of the zero-sequence current for reaching predetermined pulse amplitude in step S102
Value uniformity carries out judging whether electromagnetic potential transformer occurs ferromagnetic resonance, wherein, specifically, being obtained when in step S102
The pulse amplitude uniformity of zero-sequence current when being less than predetermined pulse amplitude uniformity, it is determined that electromagnetic potential transformer occurs
Ferromagnetic resonance.
In embodiments of the present invention, the detailed process schematic diagram of step S103 can be found in Fig. 6.As shown in fig. 6, the step
S103 may include steps of：
In step S1031, judge whether the pulse pulse amplitude uniformity of the zero-sequence current is less than 20%.Otherwise,
Perform step S101.
When the pulse arteries and veins for calculating the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration in step s 102
, it is necessary to determine whether electromagnetic potential transformer occurs ferromagnetic resonance according to pulse amplitude uniformity when rushing amplitude uniformity.When
When the pulse amplitude uniformity of zero-sequence current is less than predetermined pulse amplitude uniformity in step S102, that is, determine that electromagnetic potential is mutual
Ferromagnetic resonance occurs for sensor.In specific implementation process, above-mentioned preset value is 20%, therefore, by the arteries and veins for judging zero-sequence current
Rush whether amplitude uniformity less than 20% can determine that whether electromagnetic potential transformer occurs ferromagnetic resonance.
When the pulse amplitude uniformity of the zero-sequence current is less than 20%, determine that the electromagnetic potential transformer occurs
Ferromagnetic resonance.
When ferromagnetic resonance occurs for electromagnetic potential transformer, in step S104, control is connected in series with harmonic elimination resistance
The first controlling switch closure, to the electromagnetic potential transformer carry out harmonic elimination processing.
In embodiments of the present invention, when determining that ferromagnetic resonance occurs for electromagnetic potential transformer in step S103, then control
First controlling switch closes, and forms open delta circuit, harmonic elimination resistance and the first controlling switch of electromagnetic potential transformer
Series loop, so as to be damped by the primary circuit of harmonic elimination resistance increase electromagnetic potential transformer, so that mutual to electromagnetic potential
The ferromagnetic resonance that sensor produces is eliminated.
Using method provided in an embodiment of the present invention, predetermined pulse amplitude can be exceeded (i.e. according in certain time 80ms
The current threshold that ferromagnetic resonance harmonic elimination apparatus starts) the pulse amplitude uniformity of zero-sequence current determine electromagnetic potential transformer
Ferromagnetic resonance whether is produced, and then controls the action of the first controlling switch, makes the one of harmonic elimination resistance increase electromagnetic potential transformer
Minor loop damps, so that the ferromagnetic resonance produced to electromagnetic potential transformer quickly eliminates, so as to effectively improve ferromagnetic resonance
Harmonic elimination efficiency, avoid causing equipment frequent breakage, serious threat caused to the safe and stable operation of power grid and equipment.
Fig. 7 shows the flow diagram of another ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention.Such as Fig. 7 institutes
Show, this method may include steps of.
In step S101, judge whether current transformer is detected between electromagnetic potential transformer neutral point and ground
Zero-sequence current.
When detecting that the zero-sequence current is more than 10-100mA, in step s 102, calculate in the first preset duration
Reach the pulse amplitude uniformity of the zero-sequence current of predetermined pulse amplitude.
When calculating the pulse amplitude uniformity of zero-sequence current, in step s 103, judge that the electromagnetic potential is mutual
Whether sensor occurs ferromagnetic resonance.
When ferromagnetic resonance occurs for the electromagnetic potential transformer, in step S104, control is connected with harmonic elimination resistance
The first controlling switch closure of connection, harmonic elimination processing is carried out to the electromagnetic potential transformer.
When control is closed with the first controlling switch that harmonic elimination resistance is connected in series, in step S105, start the second meter
When device, start timing.
In embodiment disclosed by the invention, the second timer and the first timer in step S1021 can be pre-set
Distinguish, due to control the first controlling switch closure, the ferromagnetic resonance produced by harmonic elimination resistance to electromagnetic potential transformer
When carrying out harmonic elimination, it is not possible to the open delta circuit of harmonic elimination resistance and electromagnetic potential transformer is in series connection for a long time,
Otherwise harmonic elimination resistance will be burnt, therefore, it is necessary to by the second timer reclocking, when reaching default second preset duration
When, the first controlling switch is disconnected, protects harmonic elimination resistance.Certainly, can also be counted again by the first timer in this step
When.
Wherein, in implementation process, the second preset duration is pre-set duration, i.e., by disappearing in the second preset duration
Humorous resistance carries out harmonic elimination, if having resonance judgment module to disconnect immediately by the success of harmonic elimination resistance harmonic elimination in the second preset duration
First controlling switch, makes electromagnetic potential transformer come into operation again.The timing mode of second preset duration can be by falling
The mode timing of timing.
In step s 106, judge in the second preset duration, whether the pulse amplitude of the zero-sequence current is reduced to institute
Below the pulse amplitude for stating default zero-sequence current.Otherwise, first switch is controlled to disconnect.
In embodiments of the present invention, when step S105 starts timing, then the zero-sequence current of current transformer collection is read,
And judge whether the pulse amplitude of the zero-sequence current reaches the pulse of default zero-sequence current according to the pulse amplitude of zero-sequence current
Below amplitude.If in the second preset duration, the pulse amplitude of the zero-sequence current be reduced to the pulse of default zero-sequence current
When below amplitude, then terminate, while control the first controlling switch to disconnect, the ferromagnetic resonance of electromagnetic potential transformer eliminates.Such as
When the duration of fruit timing reaches the second preset time, the pulse amplitude of the zero-sequence current is not reduced to the default zero-sequence current
Pulse amplitude below, then perform step S107.Wherein, in specific implementation process, second preset duration is 50ms, i.e.,
In the case that harmonic elimination resistance input 50ms is still harmonic elimination, then harmonic elimination resistance may be burnt, influence harmonic elimination processing next time, need
The second controlling switch closure is controlled further to realize harmonic elimination, still, second preset duration is not limited to 50ms.
When the zero-sequence current is not reduced to below the pulse amplitude of the default zero-sequence current, in step s 107,
Control first controlling switch to disconnect, and control be electrically connected with the open delta circuit of the electromagnetic potential transformer the
Two controlling switches close.
In embodiments of the present invention, when the duration of timing reaches the second preset duration, the pulse amplitude of zero-sequence current is still
It is not reduced to below the pulse amplitude of the default zero-sequence current, then controls the first controlling switch to disconnect first, i.e. harmonic elimination resistance
Series circuit between the open delta circuit of electromagnetic potential transformer disconnects, while controls the second controlling switch closure,
I.e. the open delta circuit of electromagnetic potential transformer forms series loop with the second controlling switch, due to the second control in this circuit
System switch is without resistance value and without other electric elements, and therefore, the open delta circuit is just as short circuit, so as to eliminate electromagnetic type electricity
Press the ferromagnetic resonance of mutual inductor.
In implementation process of the embodiment of the present invention, when ferromagnetic resonance that electromagnetic potential transformer produces is larger, control the
Two controlling switches close certain time, in the case of can not still eliminating ferromagnetic resonance, if unanimously keeping electromagnetic potential mutual inductance
The open delta circuit short circuit of device, then may burn electromagnetic potential transformer.Therefore, the embodiment of the present invention is in above-mentioned Fig. 7
On the basis of, additionally provide another embodiment.It for details, reference can be made to shown in Fig. 8.
The detailed process schematic diagram of the ferromagnetic resonance harmonic elimination method provided as shown in Figure 8, the step S107 of this method may be used also
To include the following steps.
When the second controlling switch closure that control is electrically connected with the open delta circuit of the electromagnetic potential transformer,
In step S1071, start the 3rd timer, start timing.
In embodiment disclosed by the invention, the 3rd timer can be pre-set, the 3rd timer is different from
One timer and the second timer, so that when the second controlling switch closes, start timing by the 3rd timer.Specific real
During applying, the 3rd timer can also be the second timer or the first timer, alternatively, the first timer, the second timer
It is same timer, simply timing respectively, and independent timing in timing course each time with the 3rd timer.
In step S1072, whether the pulse amplitude of zero-sequence current described in real-time judge is reduced to the default zero sequence electricity
Below the pulse amplitude of stream.Otherwise, the second controlling switch is disconnected.
When three timers, then by receiving the zero-sequence current of current transformer collection, zero-sequence current is judged
Pulse amplitude size, and judge whether according to the size of the pulse amplitude of zero-sequence current the pulse for being less than default zero-sequence current
Amplitude, the pulse amplitude of the default zero-sequence current is 10-100mA.When the pulse amplitude of the zero-sequence current be reduced to it is default
When below the pulse amplitude of zero-sequence current, i.e. harmonic elimination success, you can disconnect the first controlling switch；When the pulse of the zero-sequence current
When amplitude is not reduced to below the pulse amplitude of default zero-sequence current, then step S1073 is performed.
In step S1073, when the pulse amplitude of the zero-sequence current is not reduced to the pulse of the default zero-sequence current
Below amplitude and when the 3rd duration of the timing reaches three preset durations, second controlling switch is controlled to disconnect.
When the pulse amplitude of zero-sequence current is not reduced to below the pulse amplitude of default zero-sequence current, and timing time does not reach
During to three preset durations, then continue to carry out harmonic elimination by the short circuit in open delta circuit；When the pulse amplitude of zero-sequence current does not drop
Below the pulse amplitude of as low as default zero-sequence current, and when timing time reaches three preset durations, then electromagnetic potential mutual inductance
The ferromagnetic resonance of device does not eliminate yet, therefore, in advance can disconnect the second controlling switch, avoid the opening of electromagnetic potential transformer
Electromagnetic potential transformer is burnt in the long-time short circuit of triangle circuit.Wherein, the 3rd preset duration is arranged to 200ms, so that
Electromagnetic potential transformer is avoided to burn., can be mutual according to electromagnetic potential but the 3rd preset duration is not limited to 200ms
The open delta circuit of sensor is set, and this will not be detailed here.
When controlling the second controlling switch to disconnect, in step S1074, when control the second controlling switch turn-off time
When reaching four preset durations, second controlling switch is controlled to close again, until the zero-sequence current is down to described preset
Below the pulse amplitude of zero-sequence current.
In embodiment disclosed by the invention, the 4th preset duration may be configured as 20-60ms, and the preferential the 4th is pre-
If duration may be configured as 40ms.There can be the 3rd timer reclocking, alternatively, the 4th timer is pre-set, by the 4th meter
When device start timing, when timing duration reaches 20-60ms, control second controlling switch to close again, make electromagnetic type electric
The open delta circuit short circuit of mutual inductor is pressed, the ferromagnetic resonance of electromagnetic potential transformer is eliminated.And repeat above-mentioned
Step S1071 to step S1073, until the pulse amplitude of the zero-sequence current be reduced to the pulse amplitude of default zero-sequence current with
Under.
Using the above method provided in an embodiment of the present invention, the harmonic elimination resistance can not be quickly mutual to the electromagnetic potential
During the quick harmonic elimination of ferromagnetic resonance that sensor produces, by resonance judgment module second controlling switch can be controlled to close, make electricity
The open delta circuit of electromagnetic type voltage transformer forms short circuit, so that the ferromagnetic resonance produced to electromagnetic potential transformer is quick
Eliminate, the elimination efficiency of ferromagnetic resonance can be further improved, greatly shorten the time that ferromagnetic resonance eliminates in the prior art.Together
When, equipment frequent breakage is avoided, serious threat is caused to the safe and stable operation of power grid and equipment.
Those skilled in the art will readily occur to the present invention its after considering specification and putting into practice the disclosure invented here
Its embodiment.This application is intended to cover the present invention any variations, uses, or adaptations, these modifications, purposes or
Person's adaptive change follows the general principle of the present invention and including undocumented common knowledge in the art of the invention
Or conventional techniques.Description and embodiments are considered only as exemplary, and true scope and spirit of the invention are by following
Claim is pointed out.
It should be appreciated that the invention is not limited in the precision architecture for being described above and being shown in the drawings, and
And various modifications and changes may be made without departing from the scope thereof.The scope of the present invention is only limited by appended claim.
Claims (10)
- A kind of 1. ferromagnetic resonance harmonic elimination method for detecting zero-sequence current pulse amplitude uniformity, it is characterised in that including：Judge whether current transformer detects the zero-sequence current between electromagnetic potential transformer neutral point and ground；When detecting that the zero-sequence current is more than default zero-sequence current, calculate and reach predetermined pulse width in the first preset duration The pulse amplitude uniformity of the zero-sequence current of value, wherein, the predetermined pulse amplitude is more than the pulse of the default zero-sequence current Amplitude；According to the pulse amplitude uniformity of the zero-sequence current for calculating and reaching predetermined pulse amplitude in the first preset duration, sentence Whether the electromagnetic potential transformer that breaks occurs ferromagnetic resonance；When ferromagnetic resonance occurs for the electromagnetic potential transformer, the first controlling switch being connected in series with harmonic elimination resistance is controlled Closure, harmonic elimination processing is carried out to the electromagnetic potential transformer.
- 2. according to the method described in claim 1, it is characterized in that, described calculate in the first preset duration reaches predetermined pulse The pulse amplitude uniformity of the zero-sequence current of amplitude, including：When detecting that the zero-sequence current is more than default zero-sequence current, start the first timer, start timing；Zero-sequence current in first preset duration of the timing is gathered by current transformer；Search the zero-sequence current that pulse amplitude is greater than or equal to predetermined pulse amplitude；Calculate the pulse amplitude uniformity that pulse amplitude is greater than or equal to the adjacent zero-sequence current of predetermined pulse amplitude.
- 3. according to the method described in claim 2, it is characterized in that, the calculating pulse amplitude is greater than or equal to predetermined pulse width The pulse amplitude uniformity of the adjacent zero-sequence current of value, including：Calculate the difference and average value of the pulse amplitude absolute value of adjacent zero-sequence current；According to the difference and average value, the pulse amplitude uniformity of adjacent zero-sequence current is determined, the pulse amplitude is consistent Property for the difference and the toaverage ratio percentage.
- 4. method according to claim 1 or 2, it is characterised in that first preset duration is 80ms, the default arteries and veins It is 100-500mA to rush amplitude.
- 5. according to the method described in claim 1, it is characterized in that, to judge whether the electromagnetic potential transformer occurs ferromagnetic Resonance, including：Judge whether the pulse amplitude uniformity of the zero-sequence current is less than 20%；When the pulse amplitude uniformity of the zero-sequence current is less than 20%, it is ferromagnetic to determine that the electromagnetic potential transformer occurs Resonance.
- 6. according to the method described in claim 1, it is characterized in that, when the first control that control is connected in series with harmonic elimination resistance is opened When closing conjunction, the method further includes：Start the second timer, start timing；Judge in the second preset duration, whether the pulse amplitude of the zero-sequence current is reduced to the arteries and veins of the default zero-sequence current Rush below amplitude；When the zero-sequence current is not reduced to below the pulse amplitude of the default zero-sequence current, control first control is opened Shut-off is opened, and the second controlling switch closure that control is electrically connected with the open delta circuit of the electromagnetic potential transformer, with Make the open delta circuit short circuit of the electromagnetic potential transformer, eliminate the ferromagnetic resonance of the electromagnetic potential transformer.
- 7. according to the method described in claim 6, it is characterized in that, second preset duration is 50ms.
- 8. according to the method described in claim 6, it is characterized in that, when control and the opening three of the electromagnetic potential transformer During the second controlling switch closure that angular convolution road is electrically connected, the method further includes：Start the 3rd timer, start timing；Whether the pulse amplitude of zero-sequence current described in real-time judge is reduced to below the pulse amplitude of the default zero-sequence current；When the pulse amplitude of the zero-sequence current is not reduced to below the pulse amplitude of the default zero-sequence current and the timing The 3rd duration when reaching three preset durations, control second controlling switch to disconnect；When controlling the second controlling switch turn-off time to reach four preset durations, second controlling switch is controlled again Closure, until the pulse amplitude of the zero-sequence current is down to below the pulse amplitude of the default zero-sequence current.
- 9. according to the method described in claim 8, it is characterized in that, the 3rd preset duration is 200ms, the described 4th is default Shi Changwei 20-60ms.
- 10. according to the method described in claim 1,2,6 or 8, it is characterised in that the pulse amplitude of the default zero-sequence current is 10-100mA。
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