CN106253226B - Detect the ferromagnetic resonance harmonic elimination method of zero-sequence current pulse width - Google Patents
Detect the ferromagnetic resonance harmonic elimination method of zero-sequence current pulse width Download PDFInfo
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- CN106253226B CN106253226B CN201610682305.4A CN201610682305A CN106253226B CN 106253226 B CN106253226 B CN 106253226B CN 201610682305 A CN201610682305 A CN 201610682305A CN 106253226 B CN106253226 B CN 106253226B
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- sequence current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/04—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers
- H02H7/05—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers for capacitive voltage transformers, e.g. against resonant conditions
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
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- Power Engineering (AREA)
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- General Physics & Mathematics (AREA)
- Inverter Devices (AREA)
- Power Conversion In General (AREA)
Abstract
The present invention relates to a kind of ferromagnetic resonance harmonic elimination method for detecting zero-sequence current pulse width, wherein, the method includes judging whether current transformer detects the zero-sequence current between electromagnetic potential transformer neutral point and ground；When detecting that the zero-sequence current reaches default zero-sequence current, the pulse width for the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration is calculated；According to the pulse width of the zero-sequence current, judge whether the electromagnetic potential transformer occurs ferromagnetic resonance；When ferromagnetic resonance occurs for the electromagnetic potential transformer, the first control switch that control is connected in series with harmonic elimination resistance is closed, 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 detect zero-sequence current pulse width
Ferromagnetic resonance harmonic elimination method.
Background technology
In the power distribution network of 66kV and below 66kV, generally use system neutral is earth-free and neutral point through low resistance or
The non-effectively earthed system of grounding through arc is connected to the electromagnetic potential transformer of monitoring insulation against ground 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 generates of the reasons 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 caused by ferromagnetic resonance, fusing 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 low resistance
Or the non-effectively earthed system (part for being accidentally detached from low resistance 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 in the relevant technologies for the ferromagnetic resonance of 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 generated 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 phenomenons 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.
Invention content
To overcome the problems in correlation technique, the present invention provides a kind of the ferromagnetic humorous of detection zero-sequence current pulse width
Shake harmonic elimination method.
It is according to embodiments of the present invention in a first aspect, providing a kind of ferromagnetic resonance harmonic elimination for detecting zero-sequence current pulse width
Method, the 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 reaches default zero-sequence current, calculate and reach default arteries and veins in the first preset duration
The pulse width of the zero-sequence current of amplitude is rushed, wherein, the predetermined pulse amplitude is more than the pulse width of the default zero-sequence current
Value；
According to the pulse width of the zero-sequence current, judge whether the electromagnetic potential transformer occurs ferromagnetic resonance；
When ferromagnetic resonance occurs for the electromagnetic potential transformer, control and harmonic elimination resistance is connected in series with first controls
Switch is closed, and harmonic elimination processing is carried out to the electromagnetic potential transformer.
Optionally, the pulse width for calculating the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration,
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 acquired by current transformer；
Search the zero-sequence current that pulse amplitude is greater than or equal to predetermined pulse amplitude；
Calculate the pulse width that pulse amplitude is greater than or equal to the zero-sequence current of predetermined pulse amplitude.
Optionally, first preset duration is 80ms, and the predetermined pulse amplitude is 100-500mA.
Optionally, judge whether the electromagnetic potential transformer occurs ferromagnetic resonance, including：
Whether the pulse width for judging the zero-sequence current is 3-40ms；
When the pulse width of the zero-sequence current is between 3-40ms, determine that the electromagnetic potential transformer occurs
Ferromagnetic resonance.
Optionally, when the first control switch that control is connected in series with harmonic elimination resistance is closed, 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 switch disconnects, and the second control switch that control is electrically connected with the open delta circuit of the electromagnetic potential transformer closes
It closes, so that the open delta circuit short circuit of the electromagnetic potential transformer, eliminates the ferromagnetic of the electromagnetic potential transformer
Resonance.
Optionally, second preset duration is 50ms.
Optionally, when the second control switch that control is electrically connected with the open delta circuit of the electromagnetic potential transformer
During closure, the method further includes：
Start third 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 the third duration of timing reaches third preset duration, control the second control switch disconnects；
When the second control switch off-time is controlled to reach four preset durations, second control is controlled again
Switch is closed, until the pulse amplitude of the zero-sequence current is down to below the pulse amplitude of the default zero-sequence current.
Optionally, the third preset duration is 200ms, and the 4th preset duration is 20-60ms.
Optionally, 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 pulse current pulse width, the side
Method includes judging whether current transformer detects the zero-sequence current between electromagnetic potential transformer neutral point and ground；Work as detection
When reaching default zero-sequence current to the zero-sequence current, the zero sequence electricity for reaching predetermined pulse amplitude in the first preset duration is calculated
The pulse width of stream；According to the pulse width 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, the be connected in series with harmonic elimination resistance first control is controlled to open
It closes and closes, harmonic elimination processing is carried out to the electromagnetic potential transformer.
The embodiment of the present invention can determine whether the electromagnetic type by the detection to zero-sequence current according to the size of zero-sequence current
Whether voltage transformer occurs ferromagnetic resonance, in case of ferromagnetic resonance, then the first control switch can be controlled to be closed, make harmonic elimination
Resistance forms series loop with open delta circuit, increases the damping of electromagnetic potential transformer primary circuit by harmonic elimination resistance, from
And the ferromagnetic resonance of electromagnetic potential transformer is quickly eliminated, and since harmonic elimination resistance is connected directly between on open delta circuit, energy
Enough accurately, ferromagnetic resonance is quickly eliminated, so as to effectively improve the harmonic elimination efficiency of ferromagnetic resonance, moreover, this is simple in structure, effectively dropped
The cost of complicated microcomputer secondary resonance elimination device that low power grid in the prior art uses.
In addition, in the present invention is implemented, by being connected in parallel one second control on harmonic elimination resistance and the first control switch
Switch, once the quick harmonic elimination of ferromagnetic resonance that can not be quickly generated by the harmonic elimination resistance to the electromagnetic potential transformer
When, the second control switch can be controlled to be closed by resonance judgment module, return the open delta of electromagnetic potential transformer
Road forms short circuit, is 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 generates quickly is eliminated, and can be further improved the elimination efficiency of ferromagnetic resonance, be greatly shortened existing skill
The time that ferromagnetic resonance is eliminated in art.
It should be understood that above general description and following detailed description are only exemplary and explanatory, not
It can the limitation present invention.
Description of the drawings
Attached drawing herein is incorporated into specification and forms the part of this specification, shows the implementation for meeting the present invention
Example, and be used to explain 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, to embodiment or will show below
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 be obtained according to these attached drawings other 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 S103 of ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention is illustrated
Figure；
Fig. 6 is the flow diagram of another ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention；
Fig. 7 is the detailed process schematic diagram of another ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention.
Specific embodiment
Here exemplary embodiment will be illustrated in detail, 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 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 device and method of some aspects being described in detail in claims, of the invention.
Fig. 1 is the structure diagram according to a kind of ferromagnetic resonance harmonic elimination apparatus shown in 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, it is described so as to provide power supply, and power module 11 can be directly connected to alternating current for resonance judgment module 12 and harmonic elimination module
Resonance judgment module 12 can be CPU (Central Processing Unit, central processing unit) or PLC (Programmable
Logic Control ler, 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
The humorous control of resistance 13 and first switch 14, the both ends of the harmonic elimination resistance 13 are connected to the electromagnetic potential transformer 17
Open delta circuit both ends, the first control switch 14 be series at the harmonic elimination resistance 13 and open delta circuit it
Between, i.e., open delta circuit, the control of harmonic elimination resistance 13 and first switch 14 form series loop, and switch 14 by the first control
Break-make make open delta circuit, harmonic elimination resistance 13 and first control switch 14 formed be closed or disconnect series loops.And
In embodiment disclosed by the invention, the resonance judgment module 12 is electrically connected to the first control switch 14, so as to be judged by resonance
Module 12 controls the break-make of the first control 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, the first control switch 14 is generally using electronic power switch or relay switch, and power module 11 is distinguished
The first control of electrical connection switch 14 and the second control switch 15, so as to the first control be controlled to switch 14 by resonance judgment module 12
Make harmonic elimination resistance 13 directly with open delta circuit in series, make its to electromagnetic potential transformer quick harmonic elimination.It is being embodied
In the process, 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, it can be utmostly
Increase the primary circuit damping of electromagnetic potential transformer 17, the ferromagnetic resonance of electromagnetic potential transformer 17 is made quickly to eliminate.
In ferromagnetic resonance harmonic elimination apparatus provided in an embodiment of the present invention, electricity can not be quickly eliminated when 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 control switch 15, the second control switch 15 is in parallel with the harmonic elimination resistance 13 and first control switch 14 to be set
It puts, and the second control switch 15 is respectively electrically connected to the both ends in the open delta circuit, passes through the second control of control 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 generates can put into the second control switch 15 when quickly eliminating, make open delta circuit with
Second control switch, 15 series connection 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 respectively with resonance judgment module 12 and harmonic elimination module, and operating voltage is provided for timer by power module 11,
The first control switch 14 and the second control switch 15 is accurately controlled to close according to the timing time of timer by resonance judgment module 12
It closes, so as to achieve the purpose that the ferromagnetic resonance to electromagnetic potential transformer 17 carries out accurate harmonic elimination, effectively improves 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
The 14, second control of the humorous control of resistance 13, first switch 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 the zero-sequence current of acquisition being sent 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 acquiring the zero-sequence current of electromagnetic potential transformer 17；Institute
It states 14 concatenation of the control of harmonic elimination resistance 13 and first switch and is series at the both ends in open delta circuit, the second control switch
15 are arranged in parallel with the control of harmonic elimination resistance 13 and first switch 14, and the second control switch 15 is concatenated to open delta circuit
Both ends.
In the case that EMR electromagnetic resonance does not occur for electromagnetic potential transformer 17 in specific implementation process, first control
14 and second control switch 15 of system switch is in, when EMR electromagnetic resonance occurs for electromagnetic potential transformer 17, judging mould by resonance
First control of the control of block 12 switch 14 is closed, and open delta circuit and harmonic elimination resistance 13 is made to form series loop, passes through harmonic elimination electricity
Resistance 13 increases the primary circuit damping of electromagnetic potential transformer 17, so as to eliminate ferromagnetic resonance；When the first control switch 14 closes
Closing preset time (such as 50ms), still without elimination, second control of the control of resonance judgment module 12 switch 15 closes ferromagnetic resonance afterwards
It closes, while the first control is switched 14 and is opened, open delta circuit is made to be controlled with second and switchs 15 and forms series loops, due to the
After two control switches 15 and open delta circuit in series, the second control 15 shape same root conducting wires of 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 can determine whether according to the size of zero-sequence current
Whether the electromagnetic potential transformer occurs ferromagnetic resonance, in case of ferromagnetic resonance, then the first control can be controlled to switch
It is closed, harmonic elimination resistance is made to form series loop with open delta circuit, it is primary to increase electromagnetic potential transformer by harmonic elimination resistance
Loop damping, so as to quickly eliminate the ferromagnetic resonance of electromagnetic potential transformer, since harmonic elimination resistance is connected directly between opening three
Angular convolution road, can accurately, quickly eliminate ferromagnetic resonance, so as to effectively improve the harmonic elimination efficiency of ferromagnetic resonance, 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 control switch
Switch, once the quick harmonic elimination of ferromagnetic resonance that can not be quickly generated by the harmonic elimination resistance to the electromagnetic potential transformer
When, the second control switch can be controlled to be closed by resonance judgment module, return the open delta of electromagnetic potential transformer
Road forms short circuit, so as to which the ferromagnetic resonance generated to electromagnetic potential transformer is quickly eliminated, can further improve ferromagnetic humorous
The elimination efficiency shaken greatly shortens the time that ferromagnetic resonance is eliminated in the prior art.
It is to be described in detail for the embodiment of device provided by the invention above, 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 acquires, and leads to
Cross control first control switch 14, second control switch 15 break-make to the ferromagnetic resonance that electromagnetic potential transformer 17 generates 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 generate sensing electric current, therefore can be detected between electromagnetic potential transformer neutral point and ground by current transformer
The size of zero-sequence current.
When detecting that zero-sequence current reaches default zero-sequence current, in step s 102, calculate in the first preset duration
Reach the pulse width of the zero-sequence current of predetermined pulse amplitude.
In embodiment disclosed by the invention, under normal circumstances, when electromagnetic potential transformer does not generate ferromagnetic resonance, still
Zero-sequence current is had, only the pulse amplitude of zero-sequence current is relatively low at this time, generally 0-0.2mA.When detection zero-sequence current is more than
During the pulse amplitude 10-100mA of default zero-sequence current, need by whether judging zero-sequence current beyond predetermined pulse amplitude, and
The pulse width of zero-sequence current within a certain period of time could judge whether electromagnetic potential transformer occurs ferromagnetic resonance.Its
In, when detect by zero-sequence current pulse amplitude be more than 10-100mA when can start timer, calculate first it is default when
Reach the pulse width of the zero-sequence current of predetermined pulse amplitude in length.In specific implementation process, first preset duration can
To be set as 80ms, wherein, the predetermined pulse amplitude is more than the pulse amplitude of the default zero-sequence current, predetermined pulse amplitude
100-500mA is can be set as, and predetermined pulse amplitude is preferably 200mA, so as to be convenient for finding ferromagnetic resonance in time
And it is eliminated.In implementation process, first preset duration and predetermined pulse amplitude be not limited to more than be embodiment
The numerical value of proposition can be determined according to the resistance value of electromagnetic potential transformer and harmonic elimination resistance, no longer be explained in detail herein
It states.
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 reaches default zero-sequence current, in step S1021, start the first timer,
Start timing.
In embodiment disclosed by the invention, the pulse width by judging the zero-sequence current in certain time is needed, into
And judge whether electromagnetic current transducer occurs EMR electromagnetic resonance, and count zero since thering is zero-sequence current to be more than 10-100mA
Therefore the pulse width of sequence electric current, when detecting that zero-sequence current is more than 10-100mA, the is carried out by starting the first timer
The timing of one preset duration 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 acquired by current transformer.
When timing starts, then zero-sequence current all in the first preset duration is acquired by current transformer, and according to note
All zero-sequence current pulse numbers of record calculate the pulse width of each zero-sequence current, convenient for step S1023 processing.
Wherein, first preset duration be 80ms, and the time of the first preset duration might not be set as 80ms, can also basis
The period of the pulse current for the ferromagnetic resonance that electromagnetic potential transformer generates is calculated, and can be the pulse electricity of ferromagnetic resonance
The multiple in the period of stream.
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 preset value, and the predetermined pulse
Amplitude is 100-500mA, and in specific implementation process, the predetermined pulse amplitude is 100-500mA, i.e. only zero-sequence current
Pulse amplitude could start ferromagnetic resonance harmonic elimination apparatus in the case of being greater than or equal to the predetermined pulse amplitude, therefore, only need
Want the zero-sequence current for being greater than or equal to predetermined pulse amplitude in finding step S1022.
When finding zero-sequence current of the pulse amplitude more than or equal to predetermined pulse amplitude, in step S1024, calculate
Pulse amplitude is greater than or equal to the pulse width of the zero-sequence current of predetermined pulse amplitude.
According to the zero-sequence current determined in step S1023, the pulse width of zero-sequence current in step S1023 is calculated.
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 width of all zero-sequence currents, further according to the pulse width of zero-sequence current
Value filters out satisfactory zero sequence pulse 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.
When the pulse number and pulse width that get the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration
When, in step s 103, judge whether the electromagnetic potential transformer occurs ferromagnetic resonance.Otherwise, step is continued to execute
S101。
In embodiments of the present invention, by showing that the pulse for the zero-sequence current for reaching predetermined pulse amplitude is wide in step S102
Degree carries out judging whether electromagnetic potential transformer occurs ferromagnetic resonance, wherein, specifically, when the zero sequence obtained in step S102
When the pulse width of electric current reaches preset pulse width, it is determined that ferromagnetic resonance occurs for electromagnetic potential transformer.
In embodiments of the present invention, the detailed process schematic diagram of step S103 can be found in Fig. 5.As shown in figure 5, the step
S103 may include steps of：
In step S1031, whether the pulse width for judging the zero-sequence current is 3-40ms.Otherwise, step is performed
S101。
When the pulse for calculating the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration in step s 102 is wide
When spending, need to determine whether electromagnetic potential transformer occurs ferromagnetic resonance according to pulse width.When zero sequence electricity in step S102
When the pulse width of stream reaches preset value, that is, determine that ferromagnetic resonance occurs for electromagnetic potential transformer.In specific implementation process,
In above-mentioned preset value pulse width be 3-40ms, preferably 3ms, therefore, by judge zero-sequence current pulse width whether
It can determine whether electromagnetic potential transformer occurs ferromagnetic resonance more than 3ms.
When the pulse width of the zero-sequence current is located at 3-40ms, it is ferromagnetic to determine that the electromagnetic potential transformer occurs
Resonance.
When ferromagnetic resonance occurs for electromagnetic potential transformer, in step S104, control is connected in series with harmonic elimination resistance
First control switch be closed, to the electromagnetic potential transformer carry out harmonic elimination processing.
In embodiments of the present invention, it when determining that ferromagnetic resonance occurs for electromagnetic potential transformer in step S103, then controls
First control switch is closed, and forms open delta circuit, harmonic elimination resistance and the first control switch of electromagnetic potential transformer
Series loop damps so as to increase the primary circuit of electromagnetic potential transformer by harmonic elimination resistance, so as to mutual to electromagnetic potential
The ferromagnetic resonance that sensor generates is eliminated.
Using method provided in an embodiment of the present invention, can according to be more than in certain time 20ms predetermined pulse amplitude (i.e.
Ferromagnetic resonance harmonic elimination apparatus start current threshold) zero-sequence current pulse number and pulse width determine that electromagnetic potential is mutual
Whether sensor generates ferromagnetic resonance, and then controls the first control switch motion, and harmonic elimination resistance is made to increase electromagnetic potential transformer
Primary circuit damping, so as to electromagnetic potential transformer generate ferromagnetic resonance quickly eliminate, it is ferromagnetic so as to effectively improve
The harmonic elimination efficiency of resonance, avoids causing equipment frequent breakage, and serious threat is caused to the safe and stable operation of power grid and equipment.
Fig. 6 shows the flow diagram of another ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention.Such as Fig. 6 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 reaches default zero-sequence current, in step s 102, calculate first it is default when
Reach the pulse width of the zero-sequence current of predetermined pulse amplitude in length.
When the pulse width for calculating zero-sequence current, in step s 103, judge that the electromagnetic potential transformer is
No generation ferromagnetic resonance.
When ferromagnetic resonance occurs for the electromagnetic potential transformer, in step S104, control is connected with harmonic elimination resistance
First control switch of connection is closed, and harmonic elimination processing is carried out to the electromagnetic potential transformer.
When the first control switch that control is connected in series with harmonic elimination resistance is closed, 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
It distinguishes, since control the first control switch is closed, the ferromagnetic resonance generated 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 made to be 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 preset second preset duration
When, the first control switch is disconnected, protects harmonic elimination resistance.Certainly, it can also again be counted 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 control 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, control first switch disconnects.
In embodiments of the present invention, when step S105 starts timing, then the zero-sequence current of current transformer acquisition 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 the first control switch is controlled to disconnect, the ferromagnetic resonance of electromagnetic potential transformer is eliminated.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 hereinafter, then performing step S107.Wherein, in specific implementation process, second preset duration is 50ms, i.e.,
Harmonic elimination resistance input 50ms still for that in the case of harmonic elimination, then may burn harmonic elimination resistance, influences harmonic elimination processing next time, needs
The second control switch is controlled to be closed and further realizes 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,
The first control switch is controlled to disconnect, and control be electrically connected with the open delta circuit of the electromagnetic potential transformer the
Two control switches are closed.
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 the predetermined pulse amplitude hereinafter, then the first control of control switch disconnection first, i.e. harmonic elimination resistance and electromagnetic type electricity
The series circuit between the open delta circuit of mutual inductor is pressed to disconnect, while the second control switch is controlled to be closed, is i.e. electromagnetic type electricity
The open delta circuit and the second control switch for pressing mutual inductor form series loop, since the second control switch is without hindrance in this circuit
It is worth and without other electric elements, therefore, the open delta circuit is just as short circuit, so as to eliminate electromagnetic potential transformer
Ferromagnetic resonance.
In implementation process of the embodiment of the present invention, when ferromagnetic resonance that electromagnetic potential transformer generates is larger, control the
Two control switches are closed 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. 6
On the basis of, additionally provide another embodiment.It for details, reference can be made to shown in Fig. 7.
The detailed process schematic diagram of the ferromagnetic resonance harmonic elimination method provided as shown in Figure 7, the step S107 of this method may be used also
To include the following steps.
When the second control switch that control is electrically connected with the open delta circuit of the electromagnetic potential transformer is closed,
In step S1071, start third timer, start timing.
In embodiment disclosed by the invention, third timer can be pre-set, the third timer is different from
One timer and the second timer, so as to when the second control switch is closed, start timing by third timer.Specific real
During applying, third timer may be the second timer or the first timer, alternatively, the first timer, the second timer
It is same timer, only timing respectively, and independent timing in timing course each time with third 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 control switch is disconnected.
When third timer, then by receiving the zero-sequence current of current transformer acquisition, 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 pulse amplitude, i.e. harmonic elimination success, you can disconnect the first control switch；When the pulse amplitude of the zero-sequence current does not reduce
When below to 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 third duration of the timing reaches third preset duration, control the second control switch disconnects.
When the pulse amplitude of zero-sequence current be not reduced to the pulse amplitude of default zero-sequence current hereinafter, and timing time do not reach
During to third preset duration, 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
Down to default zero-sequence current pulse amplitude hereinafter, and timing time reach third preset duration when, then electromagnetic potential mutual inductance
The ferromagnetic resonance of device is not eliminated yet, therefore, can in advance be disconnected the second control switch, be avoided the opening of electromagnetic potential transformer
Electromagnetic potential transformer is burnt in the long-time short circuit of triangle circuit.Wherein, the third preset duration is set as 200ms, so as to
Electromagnetic potential transformer is avoided to burn.But the third preset duration is not limited to 200ms, it can be mutual according to electromagnetic potential
The open delta circuit of sensor is set, and this will not be detailed here.
When the second control switch is controlled to disconnect, in step S1074, when control the second control switch off-time
When reaching four preset durations, the second control switch is controlled to be closed again, until the zero-sequence current is down to the zero sequence
Below the pulse amplitude of electric 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 third timer reclocking, alternatively, the 4th timer is pre-set, by the 4th meter
When device start timing, when timing duration reaches 20-60ms, the second control switch is controlled to be closed again, makes electromagnetic type electric
The open delta circuit short circuit of mutual inductor is pressed, the ferromagnetic resonance of electromagnetic potential transformer is eliminated.And it repeats above-mentioned
Step S1071 to step S1073, until the zero-sequence current pulse amplitude 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 generates, the second control switch can be controlled to be closed by resonance judgment module, make electricity
The open delta circuit of electromagnetic type voltage transformer forms short circuit, so as to which the ferromagnetic resonance generated to electromagnetic potential transformer is quick
It eliminates, the elimination efficiency of ferromagnetic resonance can be further improved, greatly shorten the time that ferromagnetic resonance is eliminated 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 illustratively, and true scope and spirit of the invention are by following
Claim is pointed out.
It should be understood 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 (9)
1. a kind of ferromagnetic resonance harmonic elimination method for detecting zero sequence pulse current pulse width, which is characterized 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 reaches default zero-sequence current, calculate and reach predetermined pulse width in the first preset duration
The pulse width of the zero-sequence current of value, wherein, the predetermined pulse amplitude is more than the pulse amplitude of the default zero-sequence current；
According to the pulse width of the zero-sequence current for calculating and reaching predetermined pulse amplitude in the first preset duration, described in judgement
Whether electromagnetic potential transformer occurs ferromagnetic resonance；
When ferromagnetic resonance occurs for the electromagnetic potential transformer, the first control that control is connected in series with harmonic elimination resistance switchs
It is closed, 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 width 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 acquired by current transformer；
Search the zero-sequence current that pulse amplitude is greater than or equal to predetermined pulse amplitude；
Calculate the pulse width that pulse amplitude is greater than or equal to the zero-sequence current of predetermined pulse amplitude.
3. method according to claim 1 or 2, which is characterized in that first preset duration be 80ms, the default arteries and veins
Amplitude is rushed as 100-500mA.
4. according to the method described in claim 1, it is characterized in that, to judge whether the electromagnetic potential transformer occurs ferromagnetic
Resonance, including：
Whether the pulse width for judging the zero-sequence current is 3-40ms；
When the pulse width of the zero-sequence current is between 3-40ms, it is ferromagnetic to determine that the electromagnetic potential transformer occurs
Resonance.
5. 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
It rushes 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
Shutdown is opened, and the second control switch that control is electrically connected with the open delta circuit of the electromagnetic potential transformer is closed, with
Make the open delta circuit short circuit of the electromagnetic potential transformer, eliminate the ferromagnetic resonance of the electromagnetic potential transformer.
6. according to the method described in claim 5, it is characterized in that, second preset duration is 50ms.
7. according to the method described in claim 5, it is characterized in that, when control and the opening three of the electromagnetic potential transformer
When second control switch of angular convolution road electrical connection is closed, the method further includes：
Start third 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
Third duration when reaching third preset duration, control the second control switch disconnects；
When the second control switch off-time is controlled to reach four preset durations, the second control switch is controlled again
It is closed, until the pulse amplitude of the zero-sequence current is down to below the pulse amplitude of the default zero-sequence current.
8. the method according to the description of claim 7 is characterized in that the third preset duration is 200ms, the described 4th is default
Shi Changwei 20-60ms.
9. according to the method described in claim 1,2,5 or 7, which is characterized in that the pulse amplitude of the default zero-sequence current is
10-100mA。
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