CN106385012B - Feeder line zero-sequence protection method and device - Google Patents
Feeder line zero-sequence protection method and device Download PDFInfo
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- CN106385012B CN106385012B CN201610862070.7A CN201610862070A CN106385012B CN 106385012 B CN106385012 B CN 106385012B CN 201610862070 A CN201610862070 A CN 201610862070A CN 106385012 B CN106385012 B CN 106385012B
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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
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
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Abstract
The present invention relates to feeder line zero-sequence protection method and devices.The method includes：Measure power frequency zero-sequence current virtual value, power frequency residual voltage virtual value and the rated line voltage virtual value of protection for feed line installation place；When according to failure through high resistance ground; the feature that the zero-sequence current and residual voltage of feeder line can all be obviously reduced; on the basis of the current setting in keeping original zero sequence excess current protection; residual voltage value is added to correct zero sequence current measurement value, and judges whether obtained correction value is more than preset feeder line zero-sequence current protection setting valve；If so, protection for feed line action cuts off this faulty line.The present invention can realize its adaptive effect to high resistant singlephase earth fault when, improve tolerance transition resistance value when the single-phase resistance eutral grounding failure through transition occurs for feeder line.
Description
Technical field
The present invention relates to power distribution network technical fields, more particularly to feeder line zero-sequence protection method and dress
It sets.
Background technology
In the power distribution network of large- and-medium size cities, cable run proportion is higher and higher, connecing when singlephase earth fault occurs
Earth-current greatly increases, and easy tos produce arc overvoltage, is adversely affected to apparatus insulated property and power supply reliability.For
This, Neutral Point Through Low Resistance mode is widely used in China's urban power distribution network.
A kind of most important fault type of the singlephase earth fault as power distribution network, in small resistance grounding system mainly according to
Stage zero-sequence current protection is relied to realize that it is quick and precisely identified.This Zero Sequence Current Protection sensitivity is by transition resistance
Influence very big, the little situation of transition resistance suitable for singlephase earth fault.
However that there are distribution overhead lines in real system is low, the reasons such as feed-in residential block are easy to happen single-phase through high resistant
Earth fault, and at present distribution network feeder frequently with Zero Sequence Current Protection in order to avoid singlephase earth fault outside area when this line
The capacitance current value on road, setting valve is generally large, causes the sensitivity to high resistance earthing fault in area relatively low, especially distance
Longer feeder line.If the little fault current long-term existence of numerical value and cannot be found that serious consequence will be led to.
For in the guard method of small resistance grounding system high resistance earthing fault, most of is by detecting earth current institute
Existing nonlinear distortion feature carries out high resistance earthing fault identification, but such methods for specific Arc Modelling or connect
The accuracy requirement of earth-current nonlinear characteristic is higher, it is difficult to cope with the complexity feature of high resistance earthing fault in power distribution network；And
Using the guard method of zero sequence power direction element, then due to the presence of neutral point low resistance so that faulty line and non-faulting
Circuit zero sequence power direction only differs 90 degree or so, therefore when high resistance ground residual voltage is smaller, be easy to cause homopolar power
The larger calculating error in direction, to judge by accident.
Invention content
Based on this, the embodiment of the present invention provides feeder line zero-sequence protection method and device, adaptive can be suitable for
High resistant singlephase earth fault improves the size of its tolerable transition resistance value.
One aspect of the present invention provides feeder line zero-sequence protection method, including：
Measure power frequency zero-sequence current virtual value, power frequency residual voltage virtual value and the rated line voltage of protection for feed line installation place
Virtual value；
Judge whether the power frequency zero-sequence current virtual value is more than or equal to preset zero-sequence current maximum unbalanced value；If
It is to execute next step；
Judge whether the power frequency zero-sequence current virtual value is more than preset feeder line zero-sequence current protection setting valve；If it is not,
Execute next step；
Judge whether the power frequency residual voltage virtual value is more than or equal to preset residual voltage and starts setting valve；If so,
Execute next step；
The correction factor of zero-sequence current is calculated according to the rated line voltage virtual value, power frequency residual voltage virtual value, and
The power frequency zero-sequence current virtual value is modified according to the correction factor, obtains the correction value of feeder line zero-sequence current；
Judge whether the correction value of the feeder line zero-sequence current is more than preset feeder line zero-sequence current protection setting valve；If
It is that protection for feed line action cuts off this faulty line.
Another aspect of the present invention provides a kind of feeder line zero-sequence current protection device, including：
Measurement module, power frequency zero-sequence current virtual value, the power frequency residual voltage for measuring protection for feed line installation place are effective
Value and rated line voltage virtual value；
First current detection module, for judging whether the power frequency zero-sequence current virtual value is more than or equal to preset zero sequence
Electric current maximum unbalanced value；If so, notifying the second current detection module；
Second current detection module, if the notice for receiving the first current detection module, judges the power frequency zero
Whether sequence current effective value is more than preset feeder line zero-sequence current protection setting valve；If it is not, notice first voltage detection module；
First voltage detection module, if the notice for receiving the second current detection module, judges the power frequency zero
Whether sequence voltage virtual value, which is more than or equal to preset residual voltage, starts setting valve；If so, notice correcting module；
Correcting module, if the notice for receiving first voltage detection module, effective according to the rated line voltage
Value, power frequency residual voltage virtual value calculate the correction factor of zero-sequence current, and according to the correction factor to the power frequency zero sequence
Current effective value is modified, and obtains the correction value of feeder line zero-sequence current；
Second voltage detection module, for judging whether the correction value of the feeder line zero-sequence current is more than preset feeder line zero
Sequence current protection setting valve；If so, notice protection execution module；
And protection execution module, if the notice for receiving second voltage detection module, protection for feed line action
Cut off this faulty line.
Above-mentioned technical proposal, when according to failure through high resistance ground, the zero-sequence current and residual voltage of feeder line all can obviously subtract
Residual voltage value is added to repair on the basis of the current setting in keeping original zero sequence excess current protection in small feature
Positive zero sequence current measurement value, correction factor increases with the increase of transition resistance, adaptive to achieve the effect that.Therefore, originally
Invention in the case where not changing original zero sequence excess current and protecting definite value, using the residual voltage of protection for feed line installation place as
The index for crossing resistance sizes is modified zero-sequence current value, to realize its adaptive effect to high resistant singlephase earth fault when
Fruit can greatly improve tolerance transition resistance value when the single-phase resistance eutral grounding failure through transition occurs for feeder line, overcome existing small
Resistance grounded system feeder line zero-sequencedirectional protection is resistant to the smaller defect of transition resistance；With other existing solution phases
Than, residual voltage amplitude information is introduced when high resistance earthing fault occurs, and original zero-sequence current protection setting valve is still suitable
With simpler reliable；And this method need to only increase on the basis of traditional feeder line zero-sequence current protection to residual voltage information
Collection and processing, be easy to Project Realization.
Description of the drawings
Fig. 1 is the schematic flow chart of the feeder line zero-sequence protection method of an embodiment；
Fig. 2 is the application example of the feeder line zero-sequence protection method of an embodiment；
Fig. 3 is the schematic diagram of the feeder line zero-sequence current protection device of an embodiment.
Specific implementation mode
In order to make the purpose , technical scheme and advantage of the present invention be clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.
Fig. 1 is the schematic flow chart of the feeder line zero-sequence protection method of an embodiment；As shown in Figure 1, the present embodiment
In feeder line zero-sequence protection method include step：
S11 measures the power frequency zero-sequence current virtual value I of protection for feed line installation placeL0, power frequency residual voltage virtual value U0And volume
Line voltage virtual value Un；
In the present embodiment, power frequency zero-sequence current virtual value IL0For 3 times of power frequency zero-sequence currents.
S12 judges the power frequency zero-sequence current virtual value IL0It is maximum uneven whether preset zero-sequence current is more than or equal to
Value IL0.unb；If so, executing step S13；
In the present embodiment, that is, judge whether to meet IL0≥IL0.unb；If satisfied, executing step S13.If the judgement of step S12
As a result it is no, does not then execute any action, i.e., protection is without action.Preferably, feeder line zero-sequence current is carried out if periodic
Protection, then need return to step S11, continue the feeder line zero-sequence current protection of next round in the case.
S13 judges the power frequency zero-sequence current virtual value IL0Whether preset feeder line zero-sequence current protection setting valve is more than
IL0.set；If it is not, executing step S14；
In the present embodiment, that is, judge whether to meet IL0＞ IL0.set, if not satisfied, executing step S14；If step S13's sentences
Disconnected result is yes, then demonstrates the need for protection for feed line action and cut off this faulty line, without carrying out subsequent step.Preferably, if
Feeder line zero-sequence current protection is periodically carried out, then protection for feed line action needs to return after cutting off this faulty line in the case
Step S11 continues the feeder line zero-sequence current protection of next round.
S14 judges the power frequency residual voltage virtual value U0Whether it is more than or equal to preset residual voltage and starts setting valve
U0.set；If so, executing step S15；
In the present embodiment, that is, judge whether to meet U0≥U0.set, if satisfied, executing step S15；If the judgement of step S14
As a result it is no, does not then execute any action, i.e., protection is without action.Preferably, feeder line zero-sequence current is carried out if periodic
Protection, then need return to step S11, continue the feeder line zero-sequence current protection of next round in the case.
S15, according to the rated line voltage virtual value Un, power frequency residual voltage virtual value U0Calculate the amendment of zero-sequence current
COEFFICIENT K, and according to the adjusted coefficient K to the power frequency zero-sequence current virtual value IL0It is modified, obtains feeder line zero-sequence current
Correction value I '0；Execute step S16；
In the present embodiment, since when failure is through high resistance ground, the zero-sequence current and residual voltage of feeder line can all have obviously
The feature of reduction, therefore on the basis of the current setting in keeping zero sequence excess current protection, residual voltage value is added to repair
Positive zero sequence current measurement value, it is adaptive to achieve the effect that.
S16 judges the correction value I ' of the feeder line zero-sequence current0Whether adjusted more than preset feeder line zero-sequence current protection
Value IL0.set；If so, protection for feed line action cuts off this faulty line.
In the present embodiment, that is, judge whether to meet I0' ＞ IL0.set, if satisfied, protection for feed line action cuts off this fault wire
Road.
If the judging result of step S16 is no, any action is not executed, i.e., protection is without action.Preferably, if week
The carry out feeder line zero-sequence current protection of phase property, then need return to step S11 in the case, continues the feeder line zero-sequence current of next round
Protection.
As a preferred embodiment, judge to meet I in step S160' ＞ IL0.setOr judge in step S13
Meet IL0＞ IL0.setLater, the concrete mode of this faulty line of progress protection for feed line action excision can be：
Start a mask register TL；When detecting the timing of the mask register TL and whether reaching preset action delay
Long TL.setIf reaching, protection for feed line action cuts off this faulty line, and closes the mask register TL；If not up to, counting
When register TL continue timing, until its timing reaches action delay duration TL.set。
It is understood that the feeder line zero-sequence protection method of the present embodiment further includes presetting feeder line zero-sequence current
Protection seting value IL0.set, zero-sequence current maximum unbalanced value IL0.unbAnd residual voltage starts setting valve U0.setThe step of, with
And set action delay duration TL.setThe step of.
Wherein, IL0.setThe protection of setting and original zero sequence excess current be this circuit when avoiding singlephase earth fault outside area
The setting valve of the capacitance current value flowed through is identical；Set IL0.unbValue when, be likely to occur to avoid zero sequence current mutual inductor
Maximum unbalanced value, depending on need to considering the factors such as system asymmetric operation operating mode and zero sequence current mutual inductor precision；Setting
U0.setValue when the factors such as uneven residual voltage when need to consider precision, the normal operation of zero sequential potential transformer depending on.
Above-described embodiment is further detailed below.
Wherein, in step S15, zero sequence is calculated according to the rated line voltage virtual value, power frequency residual voltage virtual value
The concrete mode of the correction factor of electric current can be：
The adjusted coefficient K of zero-sequence current is calculated according to following formula：
Wherein, UnFor the rated line voltage virtual value of protection for feed line installation place, U0For the power frequency zero sequence of protection for feed line installation place
Voltage effective value.
In step S15, the power frequency zero-sequence current virtual value is modified according to the correction factor, obtains feeder line
The concrete mode of the correction value of zero-sequence current can be：
The correction value I of feeder line zero-sequence current is calculated according to following formula0′：
I0'=KIL0；
Wherein, K is correction factor, IL0For the power frequency zero-sequence current virtual value of protection for feed line installation place.
In conjunction with the feeder line zero-sequence protection method of above-described embodiment, concrete engineering application example is given below.
As shown in Fig. 2, using the data of the substation of certain 10kV low resistance grounding as model.The ground connection stood with grounding transformer
Resistance value is 12 Ω；1,2,3,4 length of feeder line is respectively 4.1km, 4.7km, 2.7km, 3.2km, the electricity that feeder line 1,2,3,4 uses
Cable model is all YJV22- 3*300, positive order parameter are：R1=0.089 Ω/km, L1=0.261mH/km, C1=0.37 μ F/km,
Zero sequence parameter is：R0=0.089 Ω/km, L0=0.783mH/km, C0=0.37 μ F/km.The load factor of distribution transformer takes
60%, and power factor takes θ=0.9 cos.Transition resistance Rf0 Ω, 600 Ω, 1200 Ω and 1500 Ω are taken respectively.
In the present embodiment, most serious situation is considered, be provided in the end of the longest feeder line of feed line length 2 single-phase through transition
Resistance eutral grounding fault point A examines the protection act situation of faulty line feeder line 2 and non-fault line feeder line 1, to verify above-mentioned reality
Apply the validity of the feeder line zero-sequence protection method of example.
The setting method of the original feeder line zero-sequencedirectional protection of the exemplary substations of Fig. 2 is：Iact=KrelIC, and consider
The capacitance current of circuit is 2A/km, safety factor Krel=1.5, so 1 original protection act value of feeder line is Iact=12.3A,
It is I that working value is done in the original protection of feeder line 2act=14.1A.Therefore, the feeder line zero-sequence current protection side based on above-described embodiment
Method, also by the zero-sequencedirectional protection setting valve I of feeder line 1 and feeder line 2L0.setRespectively 12.3A and 14.1A；Zero sequence current mutual inductor
Maximum unbalanced value IL0.unb3~10A generally is taken, in order to improve sensitivity, takes 3A here；Residual voltage starts setting valve
U0.setValue according to the precision of related zero sequential potential transformer, take 1% of rated voltage or so, take 58V here；Protection for feed line
The rated line voltage U of installation placenFor 10KV.Zero-sequence current correction value I can be obtained according to the above value0' be：
Table 1 is the measurement situation of 2 protection act of feeder line 1 and feeder line when singlephase earth fault occurs through different transition resistances：
Table 1：
(1) the zero-sequencedirectional protection situation of feeder line 2 is：
1. transition resistance RfWhen=0 Ω：
A. it measures and calculates when the single-phase resistance eutral grounding failure through transition occurs, protect the zero-sequence current of installation place effective
Value is IL0=435.90A, residual voltage virtual value are U0=5487.81V；
B. judge IL0≥IL0.unbSatisfaction and IL0＞ IL0.setMeet, mask register starts timing, and timing, which reaches, to be set
Faulty line is cut off after definite value.
2. transition resistance RfWhen=600 Ω, 1200 Ω：
A. it measures and calculates when the single-phase resistance eutral grounding failure through transition occurs, protect the zero-sequence current of installation place effective
Value is respectively IL0=9.47A, IL0=4.79A, residual voltage virtual value are respectively U0=119.27V, U0=60.27V；
B. judge IL0≥IL0.unbMeet, but IL0＞ IL0.setIt is unsatisfactory for, continues following flow；
C. judge U0≥U0.setMeet, then the correction factor that can be calculated zero-sequence current is respectively K=48.41, K=
95.79；According to formula I0'=KIL0It is respectively I that zero-sequence current correction value, which is calculated,0'=458.41A, I0'=458.85A.
D. judge I0′≥IL0.setMeet, mask register starts timing, and timing cuts off fault wire after reaching setting value
Road.
3. transition resistance RfWhen=1500 Ω：
A. it measures and calculates when the single-phase resistance eutral grounding failure through transition occurs, protect the zero-sequence current of installation place effective
Value is IL0=3.84A, residual voltage virtual value are U0=48.32A；
B. judge IL0≥IL0.unbMeet, but IL0＞ IL0.setIt is unsatisfactory for, continues following flow；
C. judge U0≥U0.setIt is unsatisfactory for, therefore protection for feed line is failure to actuate.
By can be seen that above to the protection act process analysis of feeder line 2：It is single-phase when occurring in this circuit (feeder line 2)
When through transition resistance eutral grounding failure, the higher zero sequence overcurrent of a sensitivity is carried out first and is judged, as the starting value of protection, when
Zero-sequence current value obtained by survey calculation meets IL0＞ IL0.setWhen, it, in this way can be directly into protection act is executed after line delay
The amendment link that residual voltage is needed not move through in the case that transition resistance is smaller, zero-sequence current is larger, so as to avoid amendment
Link brings the influence to protection act reliability, you can so that protection is kept for the advantages of conventional overcurrent protection；When high resistant connects
When earth fault tradition zero-sequence current protection sensitivity deficiency, that is, it is unsatisfactory for IL0＞ IL0.setWhen, then using residual voltage as zero sequence
The modified foundation of electric current makes zero-sequence current amendment since zero-sequence current adjusted coefficient K can increase with the increase of transition resistance
Value keeps a higher value, achievees the effect that adaptive, to improve protection to the sensitivity of troubles inside the sample space, enables protection
It is correctly acted in high resistance ground, cuts off this faulty line.But when transition resistance is excessive, lead to residual voltage value
It is unsatisfactory for U0≥U0.set, then protection can not be acted correctly, so there are upper limit values for the transition resistance being resistant to, by zero sequence
The influence of the various aspects such as voltage measuring transformer precision and zero sequence current mutual inductor measurement accuracy.The tolerance obtained in the present embodiment
Resistance upper limit value is 1200 Ω or so.
(2) the zero-sequencedirectional protection situation of feeder line 1 is：
1. transition resistance RfWhen=0 Ω：
A. it measures and calculates when the single-phase resistance eutral grounding failure through transition occurs, protect the zero-sequence current of installation place effective
Value is IL0=7.86A, residual voltage virtual value are U0=5487.81V；
B. judge IL0≥IL0.unbMeet, but IL0＞ IL0.setIt is unsatisfactory for, continues following flow；
C. judge U0≥U0.setMeet, the correction factor that can be calculated zero-sequence current is K=1.05, and according to formula
I0'=KIL0It is I that zero-sequence current correction value, which is calculated,0'=8.27A.
D. judge I0′≥IL0.setIt is unsatisfactory for, therefore protection for feed line is failure to actuate.
2. transition resistance RfWhen=600 Ω, 1200 Ω, 1500 Ω：
A. it measures and calculates when the single-phase resistance eutral grounding failure through transition occurs, protect the zero-sequence current of installation place effective
Value is IL0=0.17A, IL0=0.09A, IL0=0.07A, residual voltage virtual value are U0=119.27V, U0=60.27V, U0=
48.32V；
B. judge IL0≥IL0.unbIt is unsatisfactory for, therefore protection for feed line is failure to actuate.
By can be seen that above to the protection act process analysis of feeder line 1：Occur single-phase to connect through transition resistance outside area
When ground, even if meeting IL0≥IL0.unb, but since when generation singlephase earth fault, the zero-sequence current that this circuit flows through is outside area
This line-to-ground total capacitance electric current, and its increase with transition resistance and significantly reduce, therefore meeting U0≥U0.setIt is right
When zero-sequence current is modified, even if being multiplied by adjusted coefficient K, obtained correction value is also maintained at a smaller value, can not
Meet I0′≥IL0.set, therefore protection is failure to actuate.It can be seen that the feeder line zero-sequence protection method of above-described embodiment is being handled
Malfunction will not occur when external area error.
Shown by above-mentioned example：The improvement of feeder line zero-sequencedirectional protection can be protected ensuring zero-sequence current in the present invention
Under the premise of protecting selectivity, its sensitivity for high resistance earthing fault in area is effectively improved.
By the feeder line zero-sequence protection method and its engineer application example of above-described embodiment, connect through high resistant according to failure
When ground, the feature that the zero-sequence current and residual voltage of feeder line can all be obviously reduced, in keeping original zero sequence excess current protection
Current setting on the basis of, residual voltage value is added and corrects zero sequence current measurement value, correction factor is with transition resistance
Increase and increase, it is adaptive to achieve the effect that.Therefore, the present invention is in the feelings for not changing original zero sequence excess current protection definite value
Under condition, using the residual voltage of protection for feed line installation place as the index of transition resistance size, zero-sequence current value is modified,
To realize its adaptive effect to high resistant singlephase earth fault when, feeder line can be greatly improved and occur single-phase to connect through transition resistance
Tolerance transition resistance value when earth fault overcomes existing small resistance grounding system feeder line zero-sequencedirectional protection to be resistant to transition
The smaller defect of resistance；Compared with other existing solutions, residual voltage amplitude is introduced when high resistance earthing fault occurs
Information, and original zero-sequence current protection setting valve stands good, it is simpler reliable；And this method only need to be in traditional feeder line
On the basis of zero-sequence current protection, increases the collection and processing to residual voltage information, be easy to Project Realization.
It should be noted that for each method embodiment above-mentioned, describes, be all expressed as a series of for simplicity
Combination of actions, but those skilled in the art should understand that, the present invention is not limited by the described action sequence, because according to
According to the present invention, certain steps may be used other sequences or be carried out at the same time.
Based on thought identical with the feeder line zero-sequence protection method in above-described embodiment, the present invention also provides feeder lines zero
Sequence current protective device, the device can be used for executing above-mentioned feeder line zero-sequence protection method.For convenience of description, feeder line zero sequence
In the structural schematic diagram of current protective device embodiment, it illustrate only and the relevant part of the embodiment of the present invention, this field skill
Art personnel are appreciated that the restriction of schematic structure not structure twin installation, may include than illustrating more or fewer components, or
Person combines certain components or different components arrangement.
Fig. 3 is the schematic diagram of the feeder line zero-sequence current protection device of one embodiment of the invention.As shown in figure 3, this
The feeder line zero-sequence current protection device of embodiment includes：Measurement module 310, the first current detection module 320, the second current detecting
Module 330, first voltage detection module 340, correcting module 350, second voltage detection module 360 and protection execution module
370, details are as follows for each module：
The measurement module 310, power frequency zero-sequence current virtual value, power frequency zero sequence electricity for measuring protection for feed line installation place
It is pressed with valid value and rated line voltage virtual value；
Above-mentioned first current detection module 320, for judging it is pre- whether the power frequency zero-sequence current virtual value is more than or equal to
If zero-sequence current maximum unbalanced value；If so, notifying the second current detection module；
Second current detection module 330, if the notice for receiving the first current detection module, described in judgement
Whether power frequency zero-sequence current virtual value is more than preset feeder line zero-sequence current protection setting valve；If it is not, notice first voltage detection
Module；
The first voltage detection module 340, if the notice for receiving the second current detection module, described in judgement
Whether power frequency residual voltage virtual value, which is more than or equal to preset residual voltage, starts setting valve；If so, notice correcting module；
The correcting module 350, if the notice for receiving first voltage detection module, according to the specified line electricity
Be pressed with valid value, power frequency residual voltage virtual value calculates the correction factor of zero-sequence current, and according to the correction factor to the work
Frequency zero-sequence current virtual value is modified, and obtains the correction value of feeder line zero-sequence current；
The specific implementation of correcting module 350 can refer to above method embodiment.
The second voltage detection module 360, for judging it is default whether the correction value of the feeder line zero-sequence current is more than
Feeder line zero-sequence current protection setting valve；If so, notice protection execution module；
And the protection execution module 370, if the notice for receiving second voltage detection module, feeder line
Protection act cuts off this faulty line.
Preferably, second current detection module 330, if being additionally operable to judge that the power frequency zero-sequence current virtual value is big
In preset feeder line zero-sequence current protection setting valve, the protection execution module is notified；The protection execution module 370, is also used
If in the notice for receiving second current detection module, protection for feed line action cuts off this faulty line.
Preferably the protection execution module 370 includes：
Delay unit starts if the notice for receiving second current detection module or second voltage detection module
One mask register；And whether execution unit, the timing for detecting the mask register reach preset action delay
Duration, if reaching, protection for feed line action cuts off this faulty line.
As another preferred embodiment, the feeder line zero-sequence current protection device further includes：Setup module is (in figure not
Show), it is started for presetting feeder line zero-sequence current protection setting valve, zero-sequence current maximum unbalanced value and residual voltage
Setting valve；And preset action delay duration.
Pass through the feeder line zero-sequence current protection device of above-described embodiment, when according to failure through high resistance ground, the zero sequence of feeder line
The feature that electric current and residual voltage can all be obviously reduced, the base of the current setting in keeping original zero sequence excess current protection
On plinth, residual voltage value is added to correct zero sequence current measurement value, correction factor can increase with the increase of transition resistance, with
Achieve the effect that adaptive.Therefore, the present invention can greatly improve resistance to when the single-phase resistance eutral grounding failure through transition occurs for feeder line
By transition resistance value, compared with the solution proposed at present, since residual voltage and faulty line zero-sequence current is utilized
Relationship mainly determines this feature, clear physics conception by neutral point low resistance；Only zero is introduced when high resistance earthing fault occurs
Sequence voltage amplitude information, and original zero-sequence current protection setting valve stands good, therefore it is simpler reliable；And this method
It need to only increase the collection and processing to residual voltage information on the basis of traditional feeder line zero-sequence current protection, be easy to Project Realization.
It should be noted that in the embodiment of the feeder line zero-sequence current protection device of above-mentioned example, each module/unit it
Between the contents such as information exchange, implementation procedure, due to being based on same design, the skill brought with preceding method embodiment of the present invention
Art effect is identical as preceding method embodiment of the present invention, and particular content can be found in the narration in the method for the present invention embodiment, herein
It repeats no more.
In addition, in the embodiment of the feeder line zero-sequence current protection device of above-mentioned example, the logical partitioning of each function module
Be merely illustrative of, can be as needed in practical application, such as configuration requirement or software for corresponding hardware realization
It is convenient consider, above-mentioned function distribution is completed by different function modules, i.e., by the feeder line zero-sequence current protection device
Internal structure is divided into different function modules, to complete all or part of the functions described above.Wherein each function mould was both
The form that hardware may be used is realized, can also be realized in the form of software function module.
It will appreciated by the skilled person that realizing all or part of flow in above-described embodiment method, being can
It is completed with instructing relevant hardware by computer program, the program can be stored in a computer-readable storage and be situated between
In matter, sells or use as independent product.Described program when being executed, can perform the complete of the embodiment such as above-mentioned each method
Portion or part steps.Wherein, the storage medium can be magnetic disc, CD, read-only memory (Read-Only
Memory, ROM) or random access memory (Random Access Memory, RAM) etc..
In the above-described embodiments, it all emphasizes particularly on different fields to the description of each embodiment, there is no the portion being described in detail in some embodiment
Point, it may refer to the associated description of other embodiments.It is appreciated that term " first ", " second " etc. are at this used in wherein
For distinguishing object in text, but these objects should not be limited by these terms.
Several embodiments of the invention above described embodiment only expresses, should not be understood as to the scope of the claims of the present invention
Limitation.It should be pointed out that for those of ordinary skill in the art, without departing from the inventive concept of the premise,
Various modifications and improvements can be made, these are all within the scope of protection of the present invention.Therefore, the protection domain of patent of the present invention
It should be determined by the appended claims.
Claims (9)
1. a kind of feeder line zero-sequence protection method, which is characterized in that including：
The power frequency zero-sequence current virtual value, power frequency residual voltage virtual value and rated line voltage for measuring protection for feed line installation place are effective
Value；
Judge whether the power frequency zero-sequence current virtual value is more than or equal to preset zero-sequence current maximum unbalanced value；If so, holding
Row is in next step；
Judge whether the power frequency zero-sequence current virtual value is more than preset feeder line zero-sequence current protection setting valve；If it is not, executing
In next step；
Judge whether the power frequency residual voltage virtual value is more than or equal to preset residual voltage and starts setting valve；If so, executing
In next step；
According to the rated line voltage virtual value, the correction factor of power frequency residual voltage virtual value calculating zero-sequence current, and according to
The correction factor is modified the power frequency zero-sequence current virtual value, obtains the correction value of feeder line zero-sequence current；
Judge whether the correction value of the feeder line zero-sequence current is more than preset feeder line zero-sequence current protection setting valve；If so, feedback
Line protection act cuts off this faulty line；
The step of correction factor of zero-sequence current being calculated according to the rated line voltage virtual value, power frequency residual voltage virtual value
For：
The adjusted coefficient K of zero-sequence current is calculated according to following formula：
Wherein, UnFor the rated line voltage virtual value of protection for feed line installation place, U0For the power frequency residual voltage of protection for feed line installation place
Virtual value.
2. feeder line zero-sequence protection method according to claim 1, which is characterized in that judge the power frequency zero-sequence current
After the step of whether virtual value is more than preset feeder line zero-sequence current protection setting valve, further include：
If the power frequency zero-sequence current virtual value is more than preset feeder line zero-sequence current protection setting valve, protection for feed line action excision
This faulty line.
3. feeder line zero-sequence protection method according to claim 2, which is characterized in that judging the feeder line zero sequence
If the correction value of electric current is more than preset feeder line zero-sequence current protection setting valve or judges that the power frequency zero-sequence current is effective
Before the step of value is more than after preset feeder line zero-sequence current protection setting valve, and protection for feed line action cuts off this faulty line,
Including：
Start a mask register；Whether the timing for detecting the mask register reaches preset action delay duration, if reaching
It arrives, protection for feed line action cuts off this faulty line.
4. feeder line zero-sequence protection method according to claim 2, which is characterized in that according to the correction factor to institute
Stating the step of power frequency zero-sequence current virtual value is modified, obtains the correction value of feeder line zero-sequence current includes：
The correction value I of feeder line zero-sequence current is calculated according to following formula0′：
I0'=KIL0；
Wherein, K is correction factor, IL0For the power frequency zero-sequence current virtual value of protection for feed line installation place.
5. feeder line zero-sequence protection method according to claim 2, which is characterized in that further include：
Feeder line zero-sequence current protection setting valve, zero-sequence current maximum unbalanced value and residual voltage starting is preset to adjust
Value；
Further include：Preset action delay duration.
6. a kind of feeder line zero-sequence current protection device, which is characterized in that including：
Measurement module, for measure the power frequency zero-sequence current virtual value of protection for feed line installation place, power frequency residual voltage virtual value and
Rated line voltage virtual value；
First current detection module, for judging whether the power frequency zero-sequence current virtual value is more than or equal to preset zero-sequence current
Maximum unbalanced value；If so, notifying the second current detection module；
Second current detection module judges the power frequency zero sequence electricity if the notice for receiving the first current detection module
Flow whether virtual value is more than preset feeder line zero-sequence current protection setting valve；If it is not, notice first voltage detection module；
First voltage detection module judges the power frequency zero sequence electricity if the notice for receiving the second current detection module
It is pressed with whether valid value is more than or equal to preset residual voltage starting setting valve；If so, notice correcting module；
Correcting module, if the notice for receiving first voltage detection module, according to the rated line voltage virtual value, work
Frequency residual voltage virtual value calculates the correction factor of zero-sequence current, and is had to the power frequency zero-sequence current according to the correction factor
Valid value is modified, and obtains the correction value of feeder line zero-sequence current；
Second voltage detection module, for judging whether the correction value of the feeder line zero-sequence current is more than preset feeder line zero sequence electricity
Flow protection seting value；If so, notice protection execution module；
And protection execution module, if the notice for receiving second voltage detection module, protection for feed line action excision
This faulty line；
The step of correction factor of zero-sequence current being calculated according to the rated line voltage virtual value, power frequency residual voltage virtual value
For：
The adjusted coefficient K of zero-sequence current is calculated according to following formula：
Wherein, UnFor the rated line voltage virtual value of protection for feed line installation place, U0For the power frequency residual voltage of protection for feed line installation place
Virtual value.
7. feeder line zero-sequence current protection device according to claim 6, which is characterized in that the second current detecting mould
Block, if being additionally operable to judge that the power frequency zero-sequence current virtual value is more than preset feeder line zero-sequence current protection setting valve, notice
The protection execution module；
The protection execution module, if being additionally operable to receive the notice of second current detection module, protection for feed line action is cut
Except this faulty line.
8. feeder line zero-sequence current protection device according to claim 7, which is characterized in that the protection execution module packet
It includes：
Delay unit starts a meter if the notice for receiving second current detection module or second voltage detection module
When register；
Execution unit, whether the timing for detecting the mask register reaches preset action delay duration, if reaching, feedback
Line protection act cuts off this faulty line.
9. feeder line zero-sequence current protection device according to claim 8, which is characterized in that further include：
Setup module, for presetting feeder line zero-sequence current protection setting valve, zero-sequence current maximum unbalanced value and zero sequence
Voltage start setting valve；And preset action delay duration.
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| CN108037402B (en) * | 2017-11-20 | 2019-04-09 | 华南理工大学 | A kind of small resistance grounding system single-phase high-impedance detection method |
| CN108594071B (en) * | 2018-04-18 | 2020-09-25 | 广东电网有限责任公司 | Single-phase earth fault detection method for neutral point small-resistance earth distribution network |
| CN108445347A (en) * | 2018-04-28 | 2018-08-24 | 广东电网有限责任公司 | A kind of single-phase earth fault detecting method based on line equivalent impedance value |
| CN108879608B (en) * | 2018-07-12 | 2019-11-08 | 三峡大学 | Transformer zero sequence excess current guard method based on the variation of zero-sequence current phase-space distributions center of gravity amplitude |
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| CN102856891B (en) * | 2012-10-11 | 2014-11-19 | 广州嘉缘电力科技有限公司 | Self-adapting zero sequence current protection method of feeder line |
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