CN109980597A - A kind of over-current protection method based on the starting of mirror image Sudden Changing Rate - Google Patents
A kind of over-current protection method based on the starting of mirror image Sudden Changing Rate Download PDFInfo
- Publication number
- CN109980597A CN109980597A CN201910220581.2A CN201910220581A CN109980597A CN 109980597 A CN109980597 A CN 109980597A CN 201910220581 A CN201910220581 A CN 201910220581A CN 109980597 A CN109980597 A CN 109980597A
- Authority
- CN
- China
- Prior art keywords
- changing rate
- sudden changing
- starting
- mirror image
- current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/006—Calibration or setting of parameters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
-
- 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
Landscapes
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses a kind of over-current protection methods based on the starting of mirror image Sudden Changing Rate; increase after detecting Sudden Changing Rate on the basis of only sentencing a Sudden Changing Rate traditional; by newest half cycles take its mirror value and half of cycle value before previous cycle point by point again compared with a difference, for determining that the Sudden Changing Rate detected for the first time starting is that failure or because Sudden Changing Rate error starting caused by external environmental factor interference really has occurred.The present invention can be according to protection after starting for the first time; carry out the starting judgement of Sudden Changing Rate again by the mirror image waveform of subsequent half cycles; the false protection because of caused by external environment influence is avoided in the case where guaranteeing protection sensitivity, improves the reliability of protection.
Description
Technical field
The present invention relates to Relay Protection Technology in Power System fields, and in particular to a kind of mistake based on the starting of mirror image Sudden Changing Rate
Flow guard method.
Background technique
Infrastructure device of the power distribution network terminal as electrical power distribution automatization system, reliable and stable operation to entire power distribution network from
Can dynamicization system, which operate normally and play a role, conclusive influence.The reliability service of power distribution network terminal is in addition to completing
Outside basic " four is distant " function, to be also able to detect failure and quickly cut off failure.Alternate overcurrent protection is sent out using electric system
The feature that phase current significantly rises when raw phase fault realizes protection, have be swift in motion, be simple and reliable, pipe easy to set
The advantages of reason, becomes a kind of main protection form in power distribution network.Its protection process is divided into starting detection, and short circuit current judges two
Step.After detecting overcurrent starting, then judge to send out trip signal excision failure when short circuit current is more than setting valve immediately.
But because distribution terminal more install outdoors, running environment is severe, be more susceptible to external environment such as be struck by lightning surge believe
Number influence, be easy to produce protection misoperation, cause unnecessary power outage, reduce power supply reliability.For this dry
It disturbs, needs to be further optimized by the feature of analytical sampling to flow algorithm is crossed, to guarantee that power distribution network terminal is being interfered
When do not malfunction, and then guarantee protection reliability and sensitivity.
Summary of the invention
To solve deficiency in the prior art, the present invention provides a kind of overcurrent protection side based on the starting of mirror image Sudden Changing Rate
Method, into when judging whether overcurrent value surmounts the stage of electric current threshold value, passes through mirror image Sudden Changing Rate after protecting pre-boot phase
Method come determine whether for really have occurred failure still because interference caused by sampling dithering, solve power distribution network terminal because outside
Portion's environment malfunction as caused by the surging signals such as lightning stroke, in the reliability for guaranteeing to improve protection while protecting sensitivity.
In order to achieve the above objectives, the present invention adopts the following technical scheme: a kind of overcurrent based on the starting of mirror image Sudden Changing Rate
Guard method, characterized in that include:
Step 1: the phase current of data acquisition device acquisition protected circuit；Circulation stores the sampling of newest two cycles
Value；
Step 2: carrying out the calculating of difference of phase currents with formula (1) point-to-point comparison method every half cycles, obtain difference
Diff；
Diff=abs (Cur_pos-Pre_pos) (1)
In formula, Cur_pos indicates the sampled value that newest cycle sampled point head pointer is directed toward, and Pre_pos indicates the last week
The sampled value that wave sampled point head pointer is directed toward；
Step 3: judging the size of difference Diff according to formula (2), meet formula (2), then by Sudden Changing Rate number
BrkVarCount adds 1, is unsatisfactory for, and is set to 0；
Diff>DIFFDZ (2)
In formula, DIFFDZStart definite value for Sudden Changing Rate；
Step 4: judging the size of Sudden Changing Rate number brkVarCount according to formula (3), meet formula (3), then set overcurrent
Protecting " pretrigger " signal is 1；
brkVarCount>BRKVARCOUNTDZ (3)
In formula, BRKVARCOUNTDZContinuously start number definite value for Sudden Changing Rate；
Step 5: after back to back half cycles sample, such as detecting that " pretrigger " signal is 1, then by newest half
Cycle sampled value takes its mirror value along time shaft, is expressed as "-New_pos ", is carried out point by point with the value after mirror image by formula (4)
The calculating of comparison method progress difference of phase currents:
New_Diff=abs (- New_pos-Pre_pos) (4)
Step 6: whether the New_Diff that judgement newly calculates is greater than DIFFDZ, if satisfied, then by new Sudden Changing Rate number
NewBrkVarCount adds 1, is unsatisfactory for, and is set to 0；
Step 7: judging whether new Sudden Changing Rate number newBrkVarCount is greater than BRKVARCOUNTDZ, if satisfied, then
Setting overcurrent " starting " signal is 1；
Step 8: while step 7 is completed, calculating the phase current virtual value of a current newest cycle at once, obtain fault current
Value is denoted as If；
Step 9: " starting " signal being judged whether there is according to formula (5) and whether fault current is greater than overcurrent definite value Idz, such as
Meet (5), be then true over current fault, data acquisition device sends out relay protection outlet trip signal and cuts off failure:
(Act==1) && (If>Idz) (5)。
A kind of over-current protection method based on the starting of mirror image Sudden Changing Rate above-mentioned, it is characterized in that: newest two described in step 1
The minimum sampling frequency of the sampled value of a cycle is 1kHz.
A kind of over-current protection method based on the starting of mirror image Sudden Changing Rate above-mentioned, it is characterized in that: every half described in step 2
A cycle, i.e. 10ms detect a Sudden Changing Rate.
A kind of over-current protection method based on the starting of mirror image Sudden Changing Rate above-mentioned, it is characterized in that: Sudden Changing Rate starting is fixed
Value DIFFDZFlexible setting is carried out according to different occasions.
A kind of over-current protection method based on the starting of mirror image Sudden Changing Rate above-mentioned, it is characterized in that: the Sudden Changing Rate continuously opens
Dynamic number definite value BRKVARCOUNTDZFlexible setting is carried out all in accordance with different occasions.
A kind of over-current protection method based on the starting of mirror image Sudden Changing Rate above-mentioned, it is characterized in that: the calculating is current newest
The phase current virtual value of one cycle uses fourier algorithm.
Advantageous effects of the invention: the present invention can pass through subsequent half cycles according to protection after starting for the first time
Mirror image waveform carry out again Sudden Changing Rate starting judgement, guarantee protect sensitivity in the case where avoid because of external environment
False protection caused by influence improves the reliability of protection.
Detailed description of the invention
Fig. 1 is the current recording waveform diagram of normal phase-to phase fault；
Fig. 2 is the current recording waveform that external disturbance causes shake；
Fig. 3 is normal over current fault sampling instant and mirror image waveform figure；
Fig. 4 is abnormal over current fault sampling instant and mirror image waveform figure.
Specific embodiment
The invention will be further described below in conjunction with the accompanying drawings.Following embodiment is only used for clearly illustrating the present invention
Technical solution, and not intended to limit the protection scope of the present invention.
It is as shown in Figure 1 the current recording waveform diagram of normal phase-to phase fault；It is illustrated in figure 2 external disturbance and causes shake
Current recording waveform diagram, i.e., abnormal over current fault waveform diagram.
Embodiment one, judgment method when normal over current fault, it is assumed that collected over current fault waveform as shown in Figure 1,
It puts on after acquiring the moment as shown in Figure 3；
In Fig. 3, parameter declaration is as follows.
T0: fault moment starting point；
T1: the first half cycles moment starting point after failure；
T2: the 2nd half cycles moment starting point after failure；
T10: half of cycle moment starting point before failure；
T20: the complete cycle wave moment starting point before failure；
New_pos: the sampled value that the later half cycle sampled point head pointer of fault moment is directed toward；
Judgment method when normal over current fault, comprising steps of
The electric current of route is acquired, circulation stores newest two cycle sampled values, i.e. t20-t0 and t0-t2 two in Fig. 3
Two cycles between moment；
The sampled point of t0-t1 period half cycles is calculated with the point-by-point difference of sampled point of t20-t10 period half cycles and is obtained
Calculating difference point, takes the absolute value of calculated result, and judgement has continuous 4 differences point to be greater than specified threshold value, then sets overcurrent protection
" pretrigger " signal is 1；
The half cycles of t1-t2 period are negated along t axis, obtain its mirror image sample waveform, by after mirror image from t1-t2 period half cycle
The sampled point of wave carries out point-by-point difference with the sampled point of t20-t10 period half cycles and calculates acquisition calculating difference, takes calculated result
Absolute value, judgement obtains continuous 4 differences point and is greater than specified threshold value, then setting overcurrent " starting " signal is 1；
The current effective value I of t0-t2 period complete cycle wave is calculated by fourier algorithmf, protective current size is determined with overcurrent
Value compares, and virtual value is greater than overcurrent definite value, and data acquisition device sends out relay protection outlet trip signal and cuts off failure.
Embodiment two, judgment method when abnormal over current fault, it is assumed that collected over current fault waveform as shown in Fig. 2,
Put on acquisition the moment after as shown in figure 4,
Judgment method when abnormal over current fault, comprising steps of
The electric current of route is acquired, newest two cycle sampled points, i.e. two moment of t20-t0 and t0-t2 in Fig. 3 are stored
Between two cycles；
The sampled point of t0-t1 period half cycles is calculated with the point-by-point difference of sampled point of t20-t10 period half cycles and is obtained
Calculating difference takes the absolute value of calculated result, and judgement has continuous 4 differences point to be greater than specified threshold value, and overcurrent protection " is opened in advance
It is dynamic " signal is 1；
The half cycles of t1-t2 period are negated along t axis, obtain its mirror image sample waveform, by after mirror image from t1-t2 period half cycle
The sampled point of wave carries out point-by-point difference with the sampled point of t20-t10 period half cycles and calculates acquisition calculating difference, takes calculated result
Absolute value, judge that no continuous 4 differences point is greater than specified threshold value, then setting overcurrent " starting " signal is 0, is removed " in advance
Starting " mark, is set to 0, into sampling period judgement next time.
A kind of over-current protection method based on the starting of mirror image Sudden Changing Rate of the present invention, in traditional base for only sentencing a Sudden Changing Rate
Increase after detecting Sudden Changing Rate on plinth, by newest half cycles take before its mirror value and previous cycle half of cycle value by
Point compares a difference again, for determining that the Sudden Changing Rate detected for the first time starting is that failure or because outside really has occurred
Sudden Changing Rate error starting caused by environmental factor interference.
When untrue fault occurs, Distributing Terminal Assembly will send out " protection pretrigger " signal, and because being that interference causes
Sudden Changing Rate pretrigger, Sudden Changing Rate will disappear in the sampling of back to back half of cycle, therefore according to mirror image Sudden Changing Rate starting algorithm
It continuously does if the difference of acquisition will not meet and crosses threshold value, thus Distributing Terminal Assembly will not send out really that " protection is opened
It is dynamic " signal, that is, avoid the malfunction that the distribution terminal because of caused by external disturbance is protected.
When true fault occurs, Distributing Terminal Assembly will send out " protection pretrigger " signal, and because caused by non-interference
Sudden Changing Rate pretrigger, Sudden Changing Rate will not disappear in the sampling of back to back half of cycle, therefore according to mirror image Sudden Changing Rate starting algorithm
The difference of acquisition will still meet continuous several points and cross threshold value, thus Distributing Terminal Assembly by hair, really " open by protection
It is dynamic " signal, while the size for obtaining current protective current is calculated by fourier, if current protective current is greater than overcurrent definite value,
Trip protection order is then sent out, failure is cut off.
The size of the result and calculating protective current that start by differentiation mirror image Sudden Changing Rate is complete in the same duty cycle
At, therefore the differentiation of " mirror image mutation starting " ensures the quick-action of overcurrent protection, together without the time of increase protection exit
When because having carried out secondary discrimination, and improve the reliability of overcurrent protection.
The above is only a preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, without departing from the technical principles of the invention, several improvement and deformations can also be made, these improvement and deformations
Also it should be regarded as protection scope of the present invention.
Claims (6)
1. a kind of over-current protection method based on the starting of mirror image Sudden Changing Rate, characterized in that include:
Step 1: the phase current of data acquisition device acquisition protected circuit；Circulation stores the sampled value of newest two cycles；
Step 2: carrying out the calculating of difference of phase currents with formula (1) point-to-point comparison method every half cycles, obtain difference Diff；
Diff=abs (Cur_pos-Pre_pos) (1)
In formula, Cur_pos indicates the sampled value that newest cycle sampled point head pointer is directed toward, and Pre_pos indicates that previous cycle is adopted
The sampled value that sampling point head pointer is directed toward；
Step 3: judging the size of difference Diff according to formula (2), meet formula (2), then by Sudden Changing Rate number brkVarCount
Add 1, be unsatisfactory for, is set to 0；
Diff>DIFFDZ (2)
In formula, DIFFDZStart definite value for Sudden Changing Rate；
Step 4: judging the size of Sudden Changing Rate number brkVarCount according to formula (3), meet formula (3), then set overcurrent protection
" pretrigger " signal is 1；
brkVarCount>BRKVARCOUNTDZ (3)
In formula, BRKVARCOUNTDZContinuously start number definite value for Sudden Changing Rate；
Step 5: after back to back half cycles sample, such as detecting that " pretrigger " signal is 1, then by newest half of cycle
Sampled value takes its mirror value along time shaft, is expressed as "-New_pos ", carries out point-by-point comparison by formula (4) with the value after mirror image
The calculating of method progress difference of phase currents:
New_Diff=abs (- New_pos-Pre_pos) (4)
Step 6: whether the New_Diff that judgement newly calculates is greater than DIFFDZ, if satisfied, then by new Sudden Changing Rate number
NewBrkVarCount adds 1, is unsatisfactory for, and is set to 0；
Step 7: judging whether new Sudden Changing Rate number newBrkVarCount is greater than BRKVARCOUNTDZ, if satisfied, then setting
Flowing " starting " signal is 1；
Step 8: while step 7 is completed, calculating the phase current virtual value of a current newest cycle at once, obtain fault curre note
For If；
Step 9: " starting " signal being judged whether there is according to formula (5) and whether fault current is greater than overcurrent definite value Idz, such as meet
(5), then it is true over current fault, data acquisition device sends out relay protection outlet trip signal and cuts off failure:
(Act==1) && (If>Idz) (5)。
2. a kind of over-current protection method based on the starting of mirror image Sudden Changing Rate according to claim 1, it is characterized in that: step 1
Described in newest two cycles sampled value minimum sampling frequency be 1kHz.
3. a kind of over-current protection method based on the starting of mirror image Sudden Changing Rate according to claim 1, it is characterized in that: step 2
Described in every half of cycle, i.e. 10ms detects a Sudden Changing Rate.
4. a kind of over-current protection method based on the starting of mirror image Sudden Changing Rate according to claim 1, it is characterized in that: described prominent
Variable starts definite value DIFFDZFlexible setting is carried out according to different occasions.
5. a kind of over-current protection method based on the starting of mirror image Sudden Changing Rate according to claim 1, it is characterized in that: described prominent
Variable continuously starts number definite value BRKVARCOUNTDZFlexible setting is carried out all in accordance with different occasions.
6. a kind of over-current protection method based on the starting of mirror image Sudden Changing Rate according to claim 1, it is characterized in that: the meter
The phase current virtual value for calculating a current newest cycle uses fourier algorithm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910220581.2A CN109980597B (en) | 2019-03-22 | 2019-03-22 | Overcurrent protection method based on mirror image mutation starting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910220581.2A CN109980597B (en) | 2019-03-22 | 2019-03-22 | Overcurrent protection method based on mirror image mutation starting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109980597A true CN109980597A (en) | 2019-07-05 |
| CN109980597B CN109980597B (en) | 2020-12-29 |
Family
ID=67080030
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910220581.2A Active CN109980597B (en) | 2019-03-22 | 2019-03-22 | Overcurrent protection method based on mirror image mutation starting |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109980597B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101154800A (en) * | 2007-09-29 | 2008-04-02 | 吴为麟 | Method for detecting trouble electric arc and its protecting equipment |
| CN102832599A (en) * | 2012-08-24 | 2012-12-19 | 电子科技大学 | Over-current protection circuit |
| US8576529B2 (en) * | 2010-07-16 | 2013-11-05 | Richpower Microelectronics Corporation | Power stage control circuit |
| CN104332953A (en) * | 2014-11-20 | 2015-02-04 | 江苏省电力公司扬州供电公司 | Magnetizing inrush current combined blocking method based on waveform symmetry |
| CN105140892A (en) * | 2015-07-21 | 2015-12-09 | 河南行知专利服务有限公司 | Line protection method for power transmission line |
-
2019
- 2019-03-22 CN CN201910220581.2A patent/CN109980597B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101154800A (en) * | 2007-09-29 | 2008-04-02 | 吴为麟 | Method for detecting trouble electric arc and its protecting equipment |
| US8576529B2 (en) * | 2010-07-16 | 2013-11-05 | Richpower Microelectronics Corporation | Power stage control circuit |
| CN102832599A (en) * | 2012-08-24 | 2012-12-19 | 电子科技大学 | Over-current protection circuit |
| CN104332953A (en) * | 2014-11-20 | 2015-02-04 | 江苏省电力公司扬州供电公司 | Magnetizing inrush current combined blocking method based on waveform symmetry |
| CN105140892A (en) * | 2015-07-21 | 2015-12-09 | 河南行知专利服务有限公司 | Line protection method for power transmission line |
Non-Patent Citations (1)
| Title |
|---|
| 黄景光等: "基于电流突变量的自适应过电流保护新原理", 《电力系统保护与控制》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109980597B (en) | 2020-12-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11056874B2 (en) | Fault detection and protection during steady state using traveling waves | |
| RU2358273C2 (en) | Technique and device for registration of transient fault to ground | |
| CA2369429C (en) | Method for discriminating abnormal current including arc current in ac load circuit and apparatus for executing the same | |
| US7945400B2 (en) | Systems and methods for detecting high-impedance faults in a multi-grounded power distribution system | |
| US5659453A (en) | Arc burst pattern analysis fault detection system | |
| US7656626B2 (en) | Electric arc detection device, switchgear unit comprising one such device and method for detecting an electric arc | |
| Bo et al. | Positional protection of transmission line using fault generated high frequency transient signals | |
| JP7282928B2 (en) | Behavior of intelligent electronic devices during power fluctuations | |
| CN104779594A (en) | Inter-phase short circuit and single-phase grounding comprehensive protection method for small-current grounding power system | |
| WO2013023753A2 (en) | A method of distance protection of parallel transmission line | |
| US11307265B2 (en) | Earth leakage circuit breaker | |
| CN103503262A (en) | A method and an apparatus for supervision of current transformer in a differential protection system | |
| US11598800B2 (en) | Distance elements for line protection near unconventional sources | |
| CN109417284B (en) | Apparatus for determining ground fault and related method | |
| CN109980597A (en) | A kind of over-current protection method based on the starting of mirror image Sudden Changing Rate | |
| US11162994B2 (en) | Fault current calculation during transformer saturation using the waveform unsaturated region | |
| US10819261B1 (en) | Security improvements for electric power generator protection | |
| JP2022529872A (en) | How to protect your distribution and / or transmission network from short circuits | |
| KR101355765B1 (en) | Compensation method of current transformer error for detection of ultra ampere at remote terminal unit | |
| CN109245049A (en) | A kind of AC excitation synchronous electric motor rotor winding overcurrent protection method and device | |
| US11411390B2 (en) | Secure and dependable restricted earth fault protection for electric power generators and transformers | |
| CN110988454B (en) | Method for monitoring small current by apparent power and real-time disposal | |
| CN110676813B (en) | Power supply unit and method for determining Rogowski current measurement direct current component on power supply unit | |
| JP2011244593A (en) | Accident aspect decision device | |
| JP2003125532A (en) | Tracking breaker |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |