CN106207970B - Detect the ferromagnetic resonance harmonic elimination method of zero-sequence current pulse number - Google Patents
Detect the ferromagnetic resonance harmonic elimination method of zero-sequence current pulse number Download PDFInfo
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- CN106207970B CN106207970B CN201610680901.9A CN201610680901A CN106207970B CN 106207970 B CN106207970 B CN 106207970B CN 201610680901 A CN201610680901 A CN 201610680901A CN 106207970 B CN106207970 B CN 106207970B
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- zero
- sequence current
- potential transformer
- electromagnetic potential
- harmonic elimination
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Classifications
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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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
-
- 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
- H01F38/24—Voltage transformers
Abstract
The present invention relates to a kind of ferromagnetic resonance harmonic elimination methods of detection zero-sequence current pulse number, 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 is more than default zero-sequence current, the pulse number for the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration is calculated；According to the pulse number 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 detection zero-sequence current pulse numbers
Ferromagnetic resonance harmonic elimination method.
Background technology
In 66kV and 66kV power distribution networks below, 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.
Currently, mainly being used for the protection method of the ferromagnetic resonance of appearance in the related technology：In electromagnetic potential mutual inductance
Neutral point of device installs resonance eliminator additional, alternatively, using electromagnetic potential transformer residual voltage circuit install additional 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 be easy
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 there are measure loop and disappears because the method for detection residual voltage and three-phase voltage waveform is difficult to differentiate between industrial frequency resonance
Humorous circuit shares or need to detect three-phase voltage problem.
Therefore, by using above-mentioned existing harmonic elimination mode, it can not only extend the harmonic elimination time and increase harmonic elimination cost, and
And meeting extreme influence harmonic elimination efficiency, equipment frequent breakage is caused, the safe and stable operation of power grid and equipment is caused to seriously threaten.
Invention content
To overcome the problems in correlation technique, the present invention provide it is a kind of detection zero-sequence current pulse number it is ferromagnetic humorous
Shake harmonic elimination method.
According to a first aspect of the embodiments of the present invention, a kind of ferromagnetic resonance harmonic elimination of detection zero-sequence current pulse number is provided
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, calculates and reach default arteries and veins in the first preset duration
Rush the pulse number of the zero-sequence current of amplitude, wherein the predetermined pulse amplitude is more than the pulse width of the default zero-sequence current
Value；
According to the pulse number 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 number 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, starts timing；
The zero-sequence current in the 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 number 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：
Judge whether the pulse number of the zero-sequence current is less than 24；
When the pulse width of the zero-sequence current is less than 24, it is ferromagnetic humorous to determine that the electromagnetic potential transformer occurs
It shakes.
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, starts 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 the pulse amplitude of the default zero-sequence current or less, 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
When closure, the method further includes：
Start third timer, starts 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 the pulse amplitude of the default zero-sequence current or less and described
When the third duration of timing reaches third preset duration, control the second control switch disconnects；
When control the second control switch off-time reaches four preset durations, second control is controlled again
Switch is closed, until the pulse amplitude of the zero-sequence current is down to the pulse amplitude of the default zero-sequence current or less.
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 of detection zero-sequence current pulse number, the method packet
Include the zero-sequence current for judging whether current transformer detects between electromagnetic potential transformer neutral point and ground；When detecting
When stating zero-sequence current more than default zero-sequence current, the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration is calculated
Pulse number；According to the pulse number of the zero-sequence current, judge whether the electromagnetic potential transformer occurs ferromagnetic resonance；
When ferromagnetic resonance occurs for the electromagnetic potential transformer, controls the first control switch being connected in series with harmonic elimination resistance and close
It closes, 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 case of ferromagnetic resonance, then can control the first control switch and be closed, make harmonic elimination resistance
Series loop is formed with open delta circuit, the damping of electromagnetic potential transformer primary circuit is increased by harmonic elimination resistance, to fast
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, to effectively improve the harmonic elimination efficiency of ferromagnetic resonance, moreover, this is simple in structure, is effectively reduced existing
There is the cost for 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 control switch
Switch, once the quick harmonic elimination of ferromagnetic resonance that quickly electromagnetic potential transformer can not be generated by the harmonic elimination resistance
When, the second control switch can be controlled by resonance judgment module and is closed, and the open delta of electromagnetic potential transformer is made to return
Road forms short circuit, is equivalent to the energized circuit short circuit the electromagnetic potential transformer of resonant tank, to electromagnetic potential
The ferromagnetic resonance that mutual inductor generates quickly is eliminated, and can be further increased 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 is only exemplary and explanatory, not
It can the limitation present invention.
Description of the drawings
The drawings herein are incorporated into the specification and forms part of this specification, and 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 more clearly explain the embodiment of the invention or the technical proposal in the existing technology, 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, other drawings may also be obtained based on these drawings.
Fig. 1 is a kind of structural schematic 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 signal that Fig. 4 is a kind of step S102 of ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention
Figure；
The detailed process signal that Fig. 5 is a kind of step S103 of ferromagnetic resonance harmonic elimination method provided in an embodiment of the present invention
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 implementation mode
Example embodiments are described in detail here, and the example is illustrated in the accompanying drawings.Following description is related to
When attached drawing, unless otherwise indicated, the same numbers in different drawings indicate the same or similar elements.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 a kind of structural schematic diagram of ferromagnetic resonance harmonic elimination apparatus shown according to an exemplary embodiment.Such as 1 institute
Show, which may 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, to provide power supply for resonance judgment module 12 and harmonic elimination module, and power module 11 can be directly connected to alternating current, described
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 for being electrically connected to the electromagnetic potential transformer 17
Connecting wire between neutral point and ground, 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 resistance 13 and first controls switch 14, and 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, harmonic elimination resistance 13 and first control switch 14 and form series loop, and pass through the first control switch 14
Break-make make open delta circuit, harmonic elimination resistance 13 and first control switch 14 formed be closed or disconnection series loop.And
In embodiment disclosed by the invention, the resonance judgment module 12 is electrically connected to the first control switch 14, 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, to pass through harmonic elimination electricity
The resistance value of resistance 13 increases electromagnetic potential transformer loop damping successively, to eliminate the ferromagnetic of electromagnetic potential transformer generation
Resonance.Moreover, the first control switch 14 generally uses electronic power switch or relay switch, and power module 11 is distinguished
Electrical connection the first control switch 14 and second controls switch 15, to by the control of resonance judgment module 12 first control switch 14
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
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
The primary circuit damping for increasing electromagnetic potential transformer 17, makes the ferromagnetic resonance of electromagnetic potential transformer 17 quickly eliminate.
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
When 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 and the harmonic elimination resistance 13 and first control that switch 14 is in parallel to be set
It sets, and the second control switch 15 is respectively electrically connected to the both ends in the open delta circuit, passes through control the second control switch 15
Break-make make open delta circuit and second control open extension 15 formed series loops.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 and
The second control series connection of switch 15 forms short circuit, and then is eliminated to the ferromagnetic resonance of electromagnetic potential transformer.
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,
The first control switch 14 and second control switch 15 is accurately controlled by resonance judgment module 12 according to the timing time of timer to close
It closes, 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, to effectively improve to the time
Accurately 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, first controls the control switch 15 of switch 14, second 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 harmonic elimination resistance 13 and first to control the concatenation of switch 14 and be series at the both ends in open delta circuit, the second control switch
15 control switch 14 with harmonic elimination resistance 13 and first is arranged in parallel, 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
System switch 14 and second controls switch 15 and is in when EMR electromagnetic resonance occurs for electromagnetic potential transformer 17, judges mould by resonance
The control of block 12 first control switch 14 is closed, and so that open delta circuit and harmonic elimination resistance 13 is formed series loop, is passed through harmonic elimination electricity
Resistance 13 increases the primary circuit damping of electromagnetic potential transformer 17, to eliminate ferromagnetic resonance；When the first control switch 14 closes
Closing preset time (such as 50ms), still without elimination, the control of resonance judgment module 12 second control switch 15 closes ferromagnetic resonance afterwards
It closes, while the first control switch 14 being opened, so that open delta circuit is controlled the formation series loop of switch 15 with second, due to the
For two control switches 15 with after open delta circuit in series, second controls 15 shape same root conducting wire of switch, i.e. open delta circuit
Direct short-circuit, 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 can control the first control 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, 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, 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 quickly electromagnetic potential transformer can not be generated by the harmonic elimination resistance
When, the second control switch can be controlled by resonance judgment module and is closed, and the open delta of electromagnetic potential transformer is made to return
Road forms short circuit, to which the ferromagnetic resonance generated to electromagnetic potential transformer is quickly eliminated, can further increase 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 carrying out harmonic elimination processing to ferromagnetic resonance is additionally provided, 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 ferromagnetic resonance that the break-make of control the first control control switch 15 of switch 14, second generates electromagnetic potential transformer 17 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 detects 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 not will produce induced current then, 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 is more than default zero-sequence current, in step s 102, calculate in the first preset duration
Reach the pulse number 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, is under normal circumstances 10-100mA, preferably
60mA.When detecting zero-sequence current more than 10-100mA, need by judging whether zero-sequence current exceeds predetermined pulse amplitude, and
The pulse number of zero-sequence current within a certain period of time could judge whether electromagnetic potential transformer occurs ferromagnetic resonance.Its
In, it can start timer when detecting that zero-sequence current is more than 10-100mA, calculate in the first preset duration and reach default
The pulse number and pulse width of the zero-sequence current of pulse amplitude.In specific implementation process, first preset duration can be with
It is set as 80ms, wherein the predetermined pulse amplitude is more than the pulse amplitude of the default zero-sequence current, and predetermined pulse amplitude can
To be set as 100-500mA, and predetermined pulse amplitude is preferably 200mA, so as to be convenient for finding ferromagnetic resonance simultaneously in time
It is eliminated.In implementation process, first preset duration and predetermined pulse amplitude are not limited to above be that embodiment carries
The numerical value gone out can be determined according to the resistance value of electromagnetic potential transformer and harmonic elimination resistance, no longer be 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 default zero-sequence current, in step S1021, start the first timer,
Start timing.
In embodiment disclosed by the invention, the pulse number 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 sequence since zero-sequence current is more than 10-100mA
Therefore the pulse number of electric current when detecting zero-sequence current, the meter of the first preset duration is carried out by starting the first timer
When, in implementation process, timing can be carried out 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
The pulse number of all zero-sequence currents of record is convenient for step S1023 processing.Wherein, first preset duration is 80ms, and
The time of first preset duration might not be set as 80ms, the ferromagnetic resonance that can also be generated according to electromagnetic potential transformer
Period of pulse current calculated, can be the multiple in the period of the pulse current of ferromagnetic resonance.
When collecting zero-sequence currents all in the first preset duration, in step S1023, searches 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 to start the amplitude thresholds of ferromagnetic resonance harmonic elimination apparatus, and in specific implementation process, the predetermined pulse amplitude is 100-
500mA, i.e., only the pulse amplitude of zero-sequence current is likely to generate iron in the case of being greater than or equal to the predetermined pulse amplitude
Magnetic resonance, 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 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 number of the zero-sequence current of predetermined pulse amplitude.
According to the zero-sequence current determined in step S1023, the pulse number 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 walk shown in above-described embodiment
The limitation of rapid sequencing can first calculate the pulse number 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, to accelerate to suitable zero sequence
The screening of electric current quickly judges whether electromagnetic potential transformer occurs EMR electromagnetic resonance to reduce processing processing time, and
Harmonic elimination is carried out by harmonic elimination resistance, to further increase harmonic elimination efficiency.
When getting the pulse number for the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration, in step
In S103, judge whether the electromagnetic potential transformer occurs ferromagnetic resonance.Otherwise, step S101 is continued to execute.
In embodiments of the present invention, by showing that the pulse for the zero-sequence current for reaching predetermined pulse amplitude is a in step S102
Number carries out judging whether electromagnetic potential transformer occurs ferromagnetic resonance, wherein specifically, when the zero sequence obtained in step S102
When the pulse number of electric current is less than preset pulse number, 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, judge whether the pulse number of the zero-sequence current is less than 24.Otherwise, step is executed
S101。
When the pulse for calculating the zero-sequence current for reaching predetermined pulse amplitude in the first preset duration in step s 102
When number, need to determine whether electromagnetic potential transformer occurs ferromagnetic resonance according to pulse number.When zero sequence electricity in step S102
When the pulse number of stream is less than preset value, that is, determine that ferromagnetic resonance occurs for electromagnetic potential transformer.In specific implementation process,
Above-mentioned preset value is 24, therefore, by judging whether the pulse number of zero-sequence current can determine electromagnetic type electricity less than 24
Whether pressure mutual inductor occurs ferromagnetic resonance.
When the pulse number of the zero-sequence current is less than 24, it is ferromagnetic humorous to determine that the electromagnetic potential transformer occurs
It shakes.
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 open delta circuit, harmonic elimination resistance and the first control switch of electromagnetic potential transformer is made to be formed
Series loop, the primary circuit to increase electromagnetic potential transformer by harmonic elimination resistance damps, 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 80ms predetermined pulse amplitude (i.e.
The current threshold that ferromagnetic resonance harmonic elimination apparatus starts) the pulse width of zero-sequence current determine whether electromagnetic potential transformer produces
Pig iron magnetic resonance, and then the first control switch motion is controlled, so that harmonic elimination resistance is increased the primary circuit of electromagnetic potential transformer
Damping, to which the ferromagnetic resonance generated to electromagnetic potential transformer is quickly eliminated, to effectively improve the harmonic elimination of ferromagnetic resonance
Efficiency avoids causing equipment frequent breakage, causes to seriously threaten 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 detects between electromagnetic potential transformer neutral point and ground
Zero-sequence current.
When detecting that the pulse amplitude of the zero-sequence current is more than 10-100mA, in step s 102, first is calculated
Reach the pulse number of the zero-sequence current of predetermined pulse amplitude in preset duration.
When calculating the pulse number of 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 that electromagnetic potential transformer is generated by harmonic elimination resistance
When carrying out harmonic elimination, it is not possible to so that 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 preset second preset duration
When, the first control switch is disconnected, harmonic elimination resistance is protected.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 controlling the first control switch and disconnecting, 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, thening follow the steps 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
It controls the second control switch closure and further realizes harmonic elimination, still, second preset duration is not limited to 50ms.
When the zero-sequence current is not reduced to the pulse amplitude of the default zero-sequence current or less, 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 pulse amplitude of the default zero-sequence current hereinafter, then the first control of control switch disconnection, i.e. harmonic elimination resistance first
Series circuit between the open delta circuit of electromagnetic potential transformer disconnects, while controlling the second control switch and being closed,
I.e. the open delta circuit of electromagnetic potential transformer forms series loop with the second control 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, 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 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.Shown in Fig. 7.
The step S107 of the detailed process schematic diagram of the ferromagnetic resonance harmonic elimination method provided as shown in Figure 7, 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, starts 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, 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 the 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
The pulse amplitude of amplitude, 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 control switch；When the pulse of the zero-sequence current
When amplitude is not reduced to the pulse amplitude of default zero-sequence current or less, S1073 is thened follow the steps.
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
When 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, 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 controlling the second control switch disconnection, in step S1074, when control the second control switch off-time
When reaching four preset durations, the second control switch is controlled again and is closed, 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 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, control the second control switch again and be closed, keep electromagnetic type electric
The open delta circuit short circuit for pressing mutual inductor, eliminates the ferromagnetic resonance of electromagnetic potential transformer.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
When the quick harmonic elimination of ferromagnetic resonance that sensor generates, the second control switch can be controlled by resonance judgment module and is closed, electricity is made
The open delta circuit of electromagnetic type voltage transformer forms short circuit, to which the ferromagnetic resonance generated to electromagnetic potential transformer is quick
It eliminates, the elimination efficiency of ferromagnetic resonance can be further increased, greatly shorten the time that ferromagnetic resonance is eliminated in the prior art.Together
When, equipment frequent breakage is avoided, the safe and stable operation of power grid and equipment is caused to seriously threaten.
Those skilled in the art will readily occur to its of the present invention 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 includes undocumented common knowledge in the art of the invention
Or conventional techniques.The description and examples are only to be considered as illustrative, 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 architectures for being described above and being shown in the accompanying drawings, and
And various modifications and changes may be made without departing from the scope thereof.The scope of the present invention is limited only by the attached claims.
Claims (9)
1. a kind of ferromagnetic resonance harmonic elimination method of detection zero-sequence current pulse number, 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 is more than default zero-sequence current, calculates and reach predetermined pulse width in the first preset duration
The pulse number 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 number 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 number 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, starts timing；
The zero-sequence current in the 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 number 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 is 80ms, the default arteries and veins
It is 100-500mA to rush amplitude.
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：
Judge whether the pulse number of the zero-sequence current is less than 24；
When the pulse number of the zero-sequence current is less than 24, determine that ferromagnetic resonance occurs for the electromagnetic potential transformer.
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, starts 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 amplitude or less；
When the zero-sequence current is not reduced to the pulse amplitude of the default zero-sequence current or less, 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
The open delta circuit short circuit for making the electromagnetic potential transformer, eliminates 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 controlling the opening three with the electromagnetic potential transformer
When second control switch of angular convolution road electrical connection is closed, the method further includes：
Start third timer, starts timing；
Whether the pulse amplitude of zero-sequence current described in real-time judge is reduced to the pulse amplitude of the default zero-sequence current or less；
When the pulse amplitude of the zero-sequence current is not reduced to the pulse amplitude of the default zero-sequence current or less and the timing
Third duration when reaching third preset duration, control the second control switch disconnects；
When control the second control switch off-time reaches 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 the pulse amplitude of the default zero-sequence current or less.
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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| CN113161993B (en) * | 2021-02-23 | 2023-01-20 | 广东电网有限责任公司电力科学研究院 | Low-frequency oscillation suppression method and device for electromagnetic voltage transformer |
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| CN202916384U (en) * | 2012-09-11 | 2013-05-01 | 陈昌鹏 | Improved voltage transformer zero sequence circuit system capable of improving precision of line selection and fault positioning |
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