CN110224382A - Micro-capacitance sensor relay protecting method and device - Google Patents
Micro-capacitance sensor relay protecting method and device Download PDFInfo
- Publication number
- CN110224382A CN110224382A CN201910570922.9A CN201910570922A CN110224382A CN 110224382 A CN110224382 A CN 110224382A CN 201910570922 A CN201910570922 A CN 201910570922A CN 110224382 A CN110224382 A CN 110224382A
- Authority
- CN
- China
- Prior art keywords
- micro
- capacitance sensor
- module
- overcurrent protection
- isolated island
- 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
- H02H3/08—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
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measurement Of Resistance Or Impedance (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The present invention provides micro-capacitance sensor relay protecting method and device; by the way that genetic algorithm real-time prediction model is arranged; according to historical current data in micro-capacitance sensor; the current conditions of next cycle are predicted in real time; comparison prediction value and sampled data in practical micro-capacitance sensor afterwards, and then determine whether there is short trouble in micro-capacitance sensor.Firstly, by the real-time prediction of genetic algorithm, very good solution conventional overcurrent protection is set merely by definite value to determine whether there is short trouble to occur, frequently result in the problem of shielding failure, greatly improves protection sensitivity and timeliness；Secondly, comprehensive protection needs when can meet 400V and micro-capacitance sensor isolated power grid below；Again, it can adapt to switching of the micro-capacitance sensor between isolated network and grid-connected two kinds of working conditions, finally, the various failures of micro-capacitance sensor can be recognized, and make correct response, ensure the safe and stable operation of micro-capacitance sensor.
Description
Technical field
The present invention relates to electric system micro-capacitance sensor protection technique field, in particular to a kind of micro-capacitance sensor relay protecting method.
Meanwhile the invention further relates to a kind of micro-capacitance sensor protective relaying devices.
Background technique
Micro-capacitance sensor refers to by groups such as distributed generation resource, energy storage device, energy conversion device, load, monitoring and protective devices
At small-sized electric system, being one can be realized self-contr ol, protection and the autonomous system of management, both may be coupled to
Operation (referred to as " grid-connected " operation) on external bulk power grid, can also disengaging external bulk power grid isolated operation, (referred to as " isolated network " is transported
Row).Micro-capacitance sensor has become national grid peak load shifting, improves system stability and realizes that one kind of demand side management has in recent years
Effect means.
But with the fast development of micro-capacitance sensor technology, more and more problems is exposed, such as traditional relay protection
Device has not adapted to the protection of micro-capacitance sensor.This is because the protection technique of micro-capacitance sensor is relative complex: relay traditional first is protected
Protection unit can't adapt to the off-network (isolated island) and grid-connected switching mode of micro-capacitance sensor；Lead to secondly, traditional overcurrent protection is simple
It crosses definite value setting and judges whether faulty generation, high-power electric appliance is out of service inside micro-capacitance sensor, when short trouble occurs, by
In the route and equipment short circuit current very little of micro-capacitance sensor, therefore short circuit current is likely less than protection definite value, leads to shielding failure, passes
The overcurrent protection of system is no longer desirable for micro-capacitance sensor；Again, the very short distributed generation resource of distance large number of inside micro-capacitance sensor, very
It is easy to cause short circuit current increased dramatically, if corresponding circuit cannot be disconnected in time, the safety of micro-capacitance sensor can be generated huge
Big harm.In addition, traditional Protection Technology is designed both for the bulk power grid line applications of 10KV and the above voltage
, it is difficult to meet 400V in the perception to low current and the timeliness to the electric current of sharp increase and following micro-capacitance sensor is quickly cut
Except the protection demand of failure, i.e., it is difficult to play due protective effect in micro-capacitance sensor isolated power grid.
Study new relay protecting method as a result, to ensure that the safe and stable operation of micro-capacitance sensor becomes this field and urgently solve
Certainly the problem of.
Summary of the invention
In view of this, the present invention is directed to propose a kind of micro-capacitance sensor relay protecting method, to ensure the safe and stable of micro-capacitance sensor
Operation.
In order to achieve the above objectives, the technical scheme of the present invention is realized as follows:
A kind of micro-capacitance sensor relay protecting method, includes the following steps
A, the current waveform of point of common coupling is sampled, obtains sampled data；
B, digital filtering is carried out to the sampled data, obtains the characteristic value of fundamental wave and the characteristic value of each harmonic；
C, genetic algorithm real-time prediction model is constructed, overcurrent protection decision threshold is obtained；
D, preset isolated island decision threshold is obtained；
E, the characteristic value of fundamental wave described in comparison and the overcurrent protection decision threshold, judge whether there is short trouble,
If so, executing overcurrent protection movement；If it is not, then returning to step a；
Compare each harmonic characteristic value and the preset isolated island decision threshold, determine whether that there are island shapes
State；If so, determining whether the island state is plan isolated island；If it is not, then terminating this judgement；
Determine whether the island state is unplanned isolated island；If so, executing isolated island protection act；If it is not, then motionless
Make.
Further, in step b, the method for the digital filtering includes the following steps:
B1, omnipotent window zero point filtering algorithm calculating is carried out to the sampled data, obtains fundamental wave data and each harmonic number
According to；
B2, fast fourier transform algorithm calculating is carried out to the fundamental wave data and each harmonic data, obtains institute
State the characteristic value of fundamental wave and the characteristic value of each harmonic.
Further, the formula of the omnipotent window zero point filtering algorithm are as follows:
In formula: f1、f2For two frequencies near harmonic frequency, r is compensation radius, TsFor sample frequency；
A (1)=1；A (2)=- 2 × (cos (2 π f1Ts)cos(2πf2Ts))×r；A (3)=4 × cos (2 π f1Ts)cos(2
πf2Ts)×r2；
A (4)=- 2 × (cos (2 π f1Ts)cos(2πf2Ts))×r3；A (5)=r4；
B (1)=1；B (2)=- 2 × cos (2 π f1Ts)cos(2πf2Ts)；B (3)=4 × cos (2 π f1Ts)cos(2π
f2Ts)；
B (4)=- 2 × cos (2 π f1Ts)cos(2πf2Ts)；B (5)=1.
Further, in step c, the construction method of the genetic algorithm real-time prediction model includes the following steps:
C1, the current characteristic number for obtaining point of common coupling generate initial population as historical data；
C2, the fitness value for calculating population at individual
The corresponding fitness value of each individual is calculated according to micro-capacitance sensor group's optimization object function of foundation；It waits；
C3, selection optimum individual,
According to the calculated individual adaptation degree of step c2, selects the highest individual of fitness value and replicated；
C4, intersection
According to the given intersection factor and Crossover Strategy, the information of two father's generation is subjected to combined crosswise, is generated new
Excellent individual；
C5, variation
Random variation is carried out to individual in population；
C6, population of new generation, i.e. real-time current predicted value are generated.
Further, step c is further comprising the steps of: c7, determining the real-time current predicted value multiplied by what is manually set
Value N is set as overcurrent protection decision threshold.
Further, further comprising the steps of after step e: after f, failure vanishes, to start reclosing automatically.
Further, the reclosing is three-phase n times reclosing device.
Meanwhile the present invention also provides a kind of micro-capacitance sensor protective relaying devices, to realize above-mentioned micro-capacitance sensor relay protection side
Method.
In order to achieve the above objectives, the technical scheme of the present invention is realized as follows:
A kind of micro-capacitance sensor protective relaying device, including
Acquisition module is sampled for the current waveform to point of common coupling, by gained sampling data transmitting to number
Filter module；
Digital filtering module, it is for carrying out digital filtering to the sampled data, gained fundamental wave characteristic value and each time is humorous
The characteristic value of wave is sent to overcurrent protection determination module and isolated island determination module；
Preset isolated island decision threshold obtains module, for obtaining preset isolated island decision threshold, by the preset orphan of gained
Island decision threshold is sent to isolated island determination module；
The real-time prediction module of genetic algorithm, for obtaining real-time current predicted value, by the acquisition real-time current predicted value
It is sent to overcurrent protection decision threshold and obtains module；
Overcurrent protection decision threshold obtains module and determines gained overcurrent protection for obtaining overcurrent protection decision threshold
Threshold value is sent to overcurrent protection determination module；
Isolated island determination module, for judging whether there is isolated operation；If so, triggering unplanned isolated island determination module；
If it is not, then terminating this judgement；
Unplanned isolated island determination module, for judging whether there is unplanned isolated island；If so, triggering isolated island protects mould
Block；If it is not, being then failure to actuate；
Overcurrent protection determination module, for judging whether there is short trouble；If so, triggering overcurrent protection module；
If it is not, then triggering collection module；
Isolated island protective module, for disconnecting the tie point of the micro-capacitance sensor and bulk power grid or load；
Overcurrent protection module, for disconnecting the tie point of micro-capacitance sensor and bulk power grid and the tie point of micro-capacitance sensor internal electric source.
Further, the real-time prediction module of the genetic algorithm includes genetic algorithm real-time prediction model, constructs the something lost
Propagation algorithm real-time prediction model specifically includes the following steps:
C1, the current characteristic number for obtaining point of common coupling generate initial population as historical data；
C2, the fitness value for calculating population at individual
The corresponding fitness value of each individual is calculated according to micro-capacitance sensor group's optimization object function of foundation；It waits；
C3, selection optimum individual,
According to the calculated individual adaptation degree of step c3, selects the highest individual of fitness value and replicated；
C4, intersection
According to the given intersection factor and Crossover Strategy, the information of two father's generation is subjected to combined crosswise, is generated new
Excellent individual；
C5, variation
Random variation is carried out to individual in population；
C6, population of new generation is generated, obtains real-time overcurrent protection definite value.
Further, the micro-capacitance sensor protective relaying device further includes self-starting reclosing module, after being used for failure vanishes,
Automatic starting reclosing；The reclosing is three-phase n times reclosing device.
Compared with the existing technology, present invention has the advantage that
Using technical solution of the present invention, by the way that genetic algorithm real-time prediction model is arranged, according to history electricity in micro-capacitance sensor
Flow data is predicted the current conditions of next cycle, sampled data in rear comparison prediction value and practical micro-capacitance sensor in real time, and then is determined
It whether there is short trouble in micro-capacitance sensor.Firstly, by the real-time prediction of genetic algorithm, very good solution conventional overcurrent protection
It relies on definite value to set merely to determine whether there are problems that short trouble, frequently resulting in shielding failure, greatly improves relay
The sensitivity and timeliness of protection；Secondly, comprehensive protection needs when can meet 400V and micro-capacitance sensor isolated power grid below；Again
It is secondary, it can adapt to switching of the micro-capacitance sensor between isolated network and grid-connected two kinds of working conditions；Finally, the various events of micro-capacitance sensor can be identified
Barrier, and correct response is made, ensure the safe and stable operation of micro-capacitance sensor.
Detailed description of the invention
It, below will be to embodiment in order to illustrate more clearly of embodiment of the present invention or technical solution in the prior art
Or attached drawing needed to be used in the description of the prior art does and simply introduces, it should be apparent that, the accompanying drawings in the following description is only
It is some embodiments of the present invention, for those of ordinary skill in the art, without creative efforts,
It is also possible to obtain other drawings based on these drawings.In the accompanying drawings:
Fig. 1 is the flow chart of micro-capacitance sensor relay protecting method of the invention；
Fig. 2 is the program flow diagram of genetic algorithm real-time prediction model in micro-capacitance sensor relay protecting method of the invention；
Fig. 3 is the structural block diagram of micro-capacitance sensor protective relaying device of the invention；
Fig. 4 is the original waveform figure of micro-grid system moment PCC point phase current in the embodiment of the present invention 1；
Fig. 5 is the waveform diagram that original waveform diagram obtains after omnipotent window zero point filtering algorithm in 1 Fig. 4 of the embodiment of the present invention
Picture；
Fig. 6 is the waveform image 3 that the waveform image of fundamental wave in 1 Fig. 5 of the embodiment of the present invention is obtained through FFT；
Fig. 7 is frequency-current curve that the waveform image of triple-frequency harmonics in 1 Fig. 5 of the embodiment of the present invention is obtained through FFT；
Fig. 8 is frequency-current curve that the waveform image of quintuple harmonics in 1 Fig. 5 of the embodiment of the present invention is obtained through FFT.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Whole description.Obviously, described embodiment is only a part of the embodiments of the present invention, instead of all the embodiments.Base
It is obtained by those of ordinary skill in the art without making creative efforts every other in the embodiment of the present invention
Embodiment shall fall within the protection scope of the present invention.
One skilled in the art will appreciate that embodiments of the present invention may be implemented a kind of system, device, equipment, method or
Computer program.Therefore, the present invention can specific implementation is as follows, it may be assumed that complete hardware, complete software (including firmware,
Resident software, microcode etc.) or hardware and software combine form.
In addition, any number of elements in attached drawing is used to example rather than limitation and any name are only used for distinguishing,
Without any restrictions meaning.
It should be noted that in the absence of conflict, the feature in embodiment and embodiment in the present invention can phase
Mutually combination.
The present invention relates to micro-capacitance sensor relay protecting method, main design idea is: passing through the real-time pre- of genetic algorithm
It surveys, the protection of very good solution conventional overcurrent is set merely by definite value to determine whether there is short trouble to occur, frequently result in
The problem of shielding failure.
By the setting of the whole design thought, it can be improved the sensitivity and timeliness of relay protection, be finally reached guarantee
The purpose of the safe and stable operation of micro-capacitance sensor.
Based on design philosophy as above, in the specific limits scheme of one of which of the invention, micro-capacitance sensor relay protecting method is (such as
Fig. 1), including the following steps:
A, the current waveform of point of common coupling is sampled, obtains sampled data；
B, digital filtering is carried out to the sampled data, obtains the characteristic value of fundamental wave and the characteristic value of each harmonic；
C, genetic algorithm real-time prediction model is constructed, overcurrent protection decision threshold is obtained；
D, preset isolated island decision threshold is obtained；
E, the characteristic value of fundamental wave described in comparison and the overcurrent protection decision threshold, judge whether there is short trouble, if
It is then to execute overcurrent protection movement；If it is not, then returning to step a；If it is determined that short trouble is not present in system, then by step b
Middle the data obtained and data acquisition time save, the input as genetic algorithm real-time prediction model；If it is determined that there are short for system
Road failure, the then input using last predicted value as genetic algorithm real-time prediction model.
Compare each harmonic characteristic value and the preset isolated island decision threshold, determine whether that there are island shapes
State；If so, determining whether the island state is unplanned isolated island；If it is not, then terminating this judgement；
Determine whether the island state is unplanned isolated island；If so, executing isolated island protection act；If it is not, then motionless
Make.Wherein, plan isolated island is set manually with unplanned isolated island, and plan isolated island is set as 1, and unplanned isolated island is set as 0.If 1 shape
State is then plan isolated island, is then unplanned isolated island if 0 state.
Using technical solution of the present invention, by the way that genetic algorithm real-time prediction model is arranged, according to history electricity in micro-capacitance sensor
Flow data is predicted the current conditions of next cycle, sampled data in rear comparison prediction value and practical micro-capacitance sensor in real time, and then is determined
Whether there is short trouble in micro-capacitance sensor.Firstly, by the real-time prediction of genetic algorithm, very good solution conventional overcurrent guarantor
Shield merely by definite value setting to determine whether it is faulty occur, frequently result in the problem of shielding failure, greatly improve protection
Sensitivity and timeliness；Secondly, comprehensive protection needs when can meet 400V and micro-capacitance sensor isolated power grid below；Finally, can
Switching of the micro-capacitance sensor between isolated network and grid-connected two kinds of working conditions is adapted to, ensures the safe and stable operation of micro-capacitance sensor.
In order to further increase the accuracy of micro-grid island detection method, in one of specific embodiment party of the invention
In formula, the method for the digital filtering includes the following steps:
B1, omnipotent window zero point filtering algorithm calculating is carried out to the sampled data, obtains fundamental wave data and each harmonic number
According to；
B2, fast fourier transform algorithm calculating is carried out to the fundamental wave data and each harmonic data, obtains institute
State the characteristic value of each harmonic described in the characteristic value of fundamental wave.
Means of filtering only has filtering algorithm in the present invention, pure digi-tal filtering is realized, without using hardware filter.
Preferably, the formula of the omnipotent window zero point filtering algorithm are as follows:
In formula: f1、f2For two frequencies near harmonic frequency, r is compensation radius, TsFor sample frequency；
A (1)=1；A (2)=- 2 × (cos (2 π f1Ts)cos(2πf2Ts))×r；A (3)=4 × cos (2 π f1Ts)cos(2
πf2Ts)×r2；
A (4)=- 2 × (cos (2 π f1Ts)cos(2πf2Ts))×r3；A (5)=r4；
B (1)=1；B (2)=- 2 × cos (2 π f1Ts)cos(2πf2Ts)；B (3)=4 × cos (2 π f1Ts)cos(2π
f2Ts)；
B (4)=- 2 × cos (2 π f1Ts)cos(2πf2Ts)；B (5)=1.
In order to further improve the accuracy of micro-grid island detection method, in another specific embodiment party of the invention
In formula, as shown in Fig. 2, the construction method of genetic algorithm real-time prediction model described in step c includes the following steps:
C1, the current characteristic number for obtaining point of common coupling generate initial population as historical data；
C2, the fitness value for calculating population at individual
The corresponding fitness value of each individual is calculated according to micro-capacitance sensor group's optimization object function of foundation；It waits, when waiting
Between terminate to be passed to time of new data, specially 20 ± 1ms for overcurrent protection judgement；
C3, selection optimum individual,
According to the calculated individual adaptation degree of step c2, selects the highest individual of fitness value and replicated；
C4, intersection
According to the given intersection factor and Crossover Strategy, the information of two father's generation is subjected to combined crosswise, is generated new
Excellent individual；
C5, variation
Random variation is carried out to individual in population；
C6, population of new generation is generated, obtains real-time overcurrent protection definite value.
In order to further increase the accuracy of micro-grid island detection method, in a specific embodiment of the invention,
Step c is further comprising the steps of: c7, by the real-time current predicted value multiplied by the definite value N manually set, that is, be set as overcurrent guarantor
Protect decision threshold.Meanwhile in step d, the isolated island decision threshold is dynamic setting, and the method for the dynamic setting includes following
Step: the characteristic value of each harmonic d1, is obtained as historical data；D2, by the historical data multiplied by the definite value manually set
N is set as dynamic threshold.
Since harmonic content real-time change is set according to real-time condition to enhance the real-time of detection method in power distribution network
Determine dynamic threshold.GB/T 14549-1993 provides utility network harmonic voltage limit and injects the harmonic content of points of common connection
Standard are as follows: 0.38KV odd harmonic content is no more than 4%, 6-10KV odd harmonic content and is no more than 3.2%.It obtains in the recent period at least
The data that step b is obtained in 30min are as historical data, wherein the historical data are not counted in when isolated island, this makes it possible to obtain recent
The harmonic content curve of each harmonic can further obtain harmonic content in recent micro-capacitance sensor (Harmonic Contene) value: HC；
Enable it multiplied by the definite value N manually set, i.e. N*HC is dynamic threshold.Then it is determined as when harmonic content is less than dynamic threshold normal
Operating status terminates this judgement, is otherwise determined as island operation state.When fundamental wave content is less than overcurrent protection decision threshold
When, then determine that short trouble is not present, is otherwise determined to have short trouble.
In order to further ensure the safe and stable operation of micro-capacitance sensor, in another specific embodiment of the present invention, step
It is further comprising the steps of after e: after f, failure vanishes, to start reclosing automatically.Preferably, consider 80%~90% in micro-capacitance sensor
Failure is transient fault, and the reclosing is set as three-phase n times reclosing device.Wherein, N value can be set according to actual demand,
Automatic reclosing is powered after failure vanishes, improves the anti-interference ability and power supply reliability of micro-capacitance sensor.
The present invention also provides a kind of micro-capacitance sensor alone island detection system, including it is acquisition module, digital filtering module, preset prominent
Become decision threshold and obtains module, the real-time prediction module of genetic algorithm, overcurrent protection decision threshold acquisition module, isolated island judgement mould
Block, unplanned isolated island determination module, overcurrent protection module and isolated island protective module (as shown in Figure 3), in which:
Acquisition module is sampled for the current waveform to point of common coupling, by gained sampling data transmitting to number
Filter module；
Digital filtering module, it is for carrying out digital filtering to the sampled data, gained fundamental wave characteristic value and each time is humorous
The characteristic value of wave is sent to overcurrent protection determination module and isolated island determination module；
Preset isolated island decision threshold obtains module, for obtaining preset isolated island decision threshold, by the preset orphan of gained
Island decision threshold is sent to isolated island determination module；
The real-time prediction module of genetic algorithm, for obtaining real-time current predicted value, by the acquisition real-time current predicted value
It is sent to overcurrent protection decision threshold and obtains module；
Overcurrent protection decision threshold obtains module and determines gained overcurrent protection for obtaining overcurrent protection decision threshold
Threshold value is sent to overcurrent protection determination module；
Isolated island determination module, for judging whether there is isolated operation；If so, triggering unplanned isolated island determination module；
If it is not, then terminating this judgement；
Unplanned isolated island determination module, for judging whether there is unplanned isolated island；If so, triggering isolated island protects mould
Block；If it is not, being then failure to actuate；
Overcurrent protection determination module, for judging whether there is short trouble；If so, triggering overcurrent protection module；If
It is no, then triggering collection module；
Isolated island protective module, for disconnecting the tie point of the micro-capacitance sensor and bulk power grid or load；
Overcurrent protection module,；For disconnecting the tie point of micro-capacitance sensor and bulk power grid and the tie point of micro-capacitance sensor internal electric source.
Preferably, the real-time prediction module of the genetic algorithm includes genetic algorithm real-time prediction model, constructs the heredity
Algorithm real-time prediction model, specifically includes the following steps:
C1, the current characteristic number for obtaining point of common coupling generate initial population as historical data；
C2, the fitness value for calculating population at individual
The corresponding fitness value of each individual is calculated according to micro-capacitance sensor group's optimization object function of foundation；It waits；
C3, selection optimum individual,
According to the calculated individual adaptation degree of step c2, selects the highest individual of fitness value and replicated；
C4, intersection
According to the given intersection factor and Crossover Strategy, the information of two father's generation is subjected to combined crosswise, is generated new
Excellent individual；
C5, variation
Random variation is carried out to individual in population；
C6, population of new generation is generated, obtains real-time overcurrent protection definite value.
It is furthermore preferred that the micro-capacitance sensor protective relaying device further includes self-starting reclosing module, after being used for failure vanishes,
Automatic starting reclosing；The reclosing is three-phase n times reclosing device.
It should be noted that the step in relay protecting method provided by the invention, can use micro-capacitance sensor relay protection
Corresponding module etc. is achieved in device, and the technical solution that those skilled in the art are referred to described device realizes the side
The step process of method, i.e. embodiment in described device can be regarded as realizing the preference of the method, and it will not be described here.
Based on whole design as above, following embodiments carry out specifically a portion concrete application under the design
It is bright.
Embodiment 1
Step 1: the current waveform of point of common coupling (PCC) being sampled, sampled data is a cycle of fundamental wave, is adopted
Sample frequency 1.6KHz；Fig. 4 is that certain time period grabs PCC point phase current original waveform figure in micro-capacitance sensor.
Step 2: digital filtering is carried out to sampled data；
The digital filtering algorithm used in the present invention are as follows: omnipotent window zero point filtering algorithm, but not limited to this, as long as it can be real
Now filter.Specifically, the formula (domain Z) of omnipotent window zero point filtering algorithm are as follows:
In formula:
A (1)=1；A (2)=- 2 × (cos (2 π f1Ts)cos(2πf2Ts))×r；A (3)=4 × cos (2 π f1Ts)cos(2
πf2Ts)×r2；
A (4)=- 2 × (cos (2 π f1Ts)cos(2πf2Ts))×r3；A (5)=r4；
B (1)=1；B (2)=- 2 × cos (2 π f1Ts)cos(2πf2Ts)；B (3)=4 × cos (2 π f1Ts)cos(2π
f2Ts)；
B (4)=- 2 × cos (2 π f1Ts)cos(2πf2Ts)；B (5)=1.
Wherein f1、f2For two frequencies near harmonic frequency, in the present embodiment, when digital filtering fundamental wave: f1=49Hz, f2
=51Hz；Digital filtering triple-frequency harmonics constantly, f1=149Hz, f2=151Hz；F when digital filtering quintuple harmonics1=249Hz, f2
=251Hz.R is compensation radius, in the present embodiment, when digital filtering fundamental wave, and r=0.75, r=when digital filtering triple-frequency harmonics
0.75, r=0.16 when digital filtering quintuple harmonics.TsFor sample frequency, in this example, Ts=1600Hz.
Note: f does not take these three numerical value of f=50Hz, 150Hz, 250Hz, this is because: when micro-capacitance sensor enters isolated operation,
May be with frequency shift (FS), therefore take respective frequencies two values progress cascade filterings nearby, it is ensured that in occurrence frequency offset
Still there is good filter effect.
By above-mentioned digital filtering algorithm, obtain through omnipotent window zero point filtering algorithm treated waveform image, such as Fig. 5 institute
Show, wherein Fig. 5 (a) is fundamental waveform image of the original waveform figure after omnipotent window zero point filtering algorithm, and Fig. 5 (b) is original wave
Triple-frequency harmonics waveform image of the shape figure after omnipotent window zero point filtering algorithm, Fig. 5 (c) are that original waveform figure is filtered through omnipotent window zero point
Quintuple harmonics waveform image after wave algorithm.Analysis chart 5 it is found that include different harmonic waves in micro-capacitance sensor original waveform figure,
Middle major harmonic is triple-frequency harmonics and quintuple harmonics.
Step 3: fast Fourier (FFT) being carried out to step 2 three obtained waveform and is calculated, its corresponding frequency-is obtained
Current curve diagram respectively corresponds fundamental wave, third and fifth harmonic as shown in Figure 6 to 8.By Fig. 6 to Fig. 8 it is found that fundamental wave
Characteristic value, triple-frequency harmonics characteristic value and quintuple harmonics characteristic value are respectively I50=2112A, I150=105.6A, I250=88.7A.
Also,
Each harmonic characteristic value input harmonics content calculation formula is calculated, obtains calculating triple-frequency harmonics content=5%, five times
Harmonic content=4.19%.
Step 4: setting dynamic threshold.
Step b is obtained in recent 30min data are obtained as historical data, wherein the history number is not counted in when isolated island
According to finally obtaining triple-frequency harmonics content in recent micro-capacitance sensor this makes it possible to obtain the harmonic content curve of recent each harmonic
(Harmonic Contene) value: HC=3.33%；Quintuple harmonics content (Harmonic Contene) value: HC=2.66%.
Enable it multiplied by the definite value N=1.2 manually set, i.e. N*HC is dynamic threshold.In the present embodiment, triple-frequency harmonics N*HC is dynamic gate
Sill are specially 4%, and quintuple harmonics N*HC is that dynamic threshold is specially 3.2%.
Step 5: isolated island determines
It is known by comparing the content and dynamic threshold of each harmonic it is found that harmonic content is greater than in step 4 in step 3
Dynamic threshold, micro-capacitance sensor is in island operation state at this time.Then, it is determined that whether the island state is unplanned isolated island；This
In embodiment, not receiving and be artificially transferred to isolated operation pattern information, island state 0 illustrates that it is unplanned isolated island, because
This, triggers isolated island protective module, disconnects the tie point of the micro-capacitance sensor and bulk power grid or load.
Step 6: obtaining overcurrent protection decision threshold
It is equipped with a real-time prediction module of genetic algorithm in micro-capacitance sensor protective relaying device, obtains last time step b and obtains
PCC current data as historical data, be inputted the real-time prediction module of genetic algorithm, obtain real-time current predicted value IN=
1550A.Enable it multiplied by the definite value N=1.2 manually set, i.e. overcurrent protection decision threshold.In the present embodiment, overcurrent protection determines
Threshold value is specially 1860A.
Step 7: overcurrent protection determines:
By comparing characteristic value and the overcurrent protection decision threshold of fundamental wave it is found that fundamental wave characteristic value is greater than step 6 in step 3
Middle overcurrent protection decision threshold.It is determined with short trouble as a result, executes overcurrent protection movement, triggers starting recloser.Its
In, overcurrent protection movement specifically: i.e. disconnection load side all power, while source side micro-capacitance sensor internal electric source and bulk power grid are disconnected
It opens, to guarantee non-transformer at short trouble, while micro-capacitance sensor internal electric source will not cause impact to influence on bulk power grid.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the invention
Within mind and principle, any modification, equivalent replacement, improvement and so on be should all be included in the protection scope of the present invention.
Claims (10)
1. a kind of micro-capacitance sensor relay protecting method, it is characterised in that: include the following steps
A, the current waveform of point of common coupling is sampled, obtains sampled data；
B, digital filtering is carried out to the sampled data, obtains the characteristic value of fundamental wave and the characteristic value of each harmonic；
C, genetic algorithm real-time prediction model is constructed, overcurrent protection decision threshold is obtained；
D, preset isolated island decision threshold is obtained；
E, the characteristic value of fundamental wave described in comparison and the overcurrent protection decision threshold, judge whether there is short trouble, if so,
Then execute overcurrent protection movement；If it is not, then returning to step a；
Compare each harmonic characteristic value and the preset isolated island decision threshold, determine whether that there are island states；If
It is then to determine whether the island state is plan isolated island；If it is not, then terminating this judgement；
Determine whether the island state is unplanned isolated island；If so, executing isolated island protection act；If it is not, being then failure to actuate.
2. micro-capacitance sensor relay protecting method according to claim 1, it is characterised in that: in step b, the digital filtering
Method includes the following steps:
B1, omnipotent window zero point filtering algorithm calculating is carried out to the sampled data, obtains fundamental wave data and each harmonic data；
B2, fast fourier transform algorithm calculating is carried out to the fundamental wave data and each harmonic data, obtains the base
The characteristic value of the characteristic value of wave and each harmonic.
3. micro-capacitance sensor relay protecting method according to claim 2, it is characterised in that: the omnipotent window zero point filtering algorithm
Formula are as follows:
In formula: f1、f2For two frequencies near harmonic frequency, r is compensation radius, TsFor sample frequency；
A (1)=1；A (2)=- 2 × (cos (2 π f1Ts)cos(2πf2Ts))×r；A (3)=4 × cos (2 π f1Ts)cos(2π
f2Ts)×r2；
A (4)=- 2 × (cos (2 π f1Ts)cos(2πf2Ts))×r3；A (5)=r4；
B (1)=1；B (2)=- 2 × cos (2 π f1Ts)cos(2πf2Ts)；B (3)=4 × cos (2 π f1Ts)cos(2πf2Ts)；
B (4)=- 2 × cos (2 π f1Ts)cos(2πf2Ts)；B (5)=1.
4. micro-capacitance sensor relay protecting method according to any one of claim 1-3, it is characterised in that: described in step c
The construction method of genetic algorithm real-time prediction model includes the following steps:
C1, the current characteristic number for obtaining point of common coupling generate initial population as historical data；
C2, the fitness value for calculating population at individual
The corresponding fitness value of each individual is calculated according to micro-capacitance sensor group's optimization object function of foundation；It waits；
C3, selection optimum individual,
According to the calculated individual adaptation degree of step c2, selects the highest individual of fitness value and replicated；
C4, intersection
According to the given intersection factor and Crossover Strategy, the information of two father's generation is subjected to combined crosswise, is generated new excellent
Elegant individual；
C5, variation
Random variation is carried out to individual in population；
C6, population of new generation, i.e. real-time current predicted value are generated.
5. micro-capacitance sensor relay protecting method according to claim 4, it is characterised in that: step c is further comprising the steps of:
C7, by the real-time current predicted value multiplied by the definite value N manually set, that is, be set as overcurrent protection decision threshold.
6. micro-capacitance sensor relay protecting method according to claim 4, it is characterised in that: further comprising the steps of after step e:
F, after failure vanishes, start reclosing automatically.
7. micro-capacitance sensor relay protecting method according to claim 6, it is characterised in that: the reclosing is three-phase n times weight
Closing device.
8. a kind of micro-capacitance sensor protective relaying device, it is characterised in that: including
Acquisition module is sampled for the current waveform to point of common coupling, by gained sampling data transmitting to digital filtering
Module；
Digital filtering module, for carrying out digital filtering to the sampled data, by gained fundamental wave characteristic value and each harmonic
Characteristic value is sent to overcurrent protection determination module and isolated island determination module；
Preset isolated island decision threshold obtains module and sentences the preset isolated island of gained for obtaining preset isolated island decision threshold
Determine threshold value and is sent to isolated island determination module；
The real-time prediction module of genetic algorithm sends the acquisition real-time current predicted value for obtaining real-time current predicted value
Module is obtained to overcurrent protection decision threshold；
Overcurrent protection decision threshold obtains module, for obtaining overcurrent protection decision threshold, by gained overcurrent protection decision threshold
It is sent to overcurrent protection determination module；
Isolated island determination module, for judging whether there is isolated operation；If so, triggering unplanned isolated island determination module；If it is not,
Then terminate this judgement；
Unplanned isolated island determination module, for judging whether there is unplanned isolated island；If so, triggering isolated island protective module；If
It is no, then it is failure to actuate；
Overcurrent protection determination module, for judging whether there is short trouble；If so, triggering overcurrent protection module；If it is not,
Then triggering collection module；
Isolated island protective module, for disconnecting the tie point of the micro-capacitance sensor and bulk power grid or load；
Overcurrent protection module, for disconnecting the tie point of micro-capacitance sensor and bulk power grid and the tie point of micro-capacitance sensor internal electric source.
9. micro-capacitance sensor protective relaying device according to claim 8, it is characterised in that: the genetic algorithm predicts mould in real time
Block includes genetic algorithm real-time prediction model, constructs the genetic algorithm real-time prediction model and specifically includes the following steps:
C1, the current characteristic number for obtaining point of common coupling generate initial population as historical data；
C2, the fitness value for calculating population at individual
The corresponding fitness value of each individual is calculated according to micro-capacitance sensor group's optimization object function of foundation；It waits；
C3, selection optimum individual,
According to the calculated individual adaptation degree of step c3, selects the highest individual of fitness value and replicated；
C4, intersection
According to the given intersection factor and Crossover Strategy, the information of two father's generation is subjected to combined crosswise, is generated new excellent
Elegant individual；
C5, variation
Random variation is carried out to individual in population；
C6, population of new generation is generated, obtains real-time overcurrent protection definite value.
10. the micro-capacitance sensor protective relaying device according to any one of claim 8 or 9, it is characterised in that: the micro-capacitance sensor
Protective relaying device further includes self-starting reclosing module, for starting reclosing automatically after failure vanishes；The reclosing is
Three-phase n times reclosing device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910570922.9A CN110224382B (en) | 2019-06-28 | 2019-06-28 | Micro-grid relay protection method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910570922.9A CN110224382B (en) | 2019-06-28 | 2019-06-28 | Micro-grid relay protection method and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110224382A true CN110224382A (en) | 2019-09-10 |
| CN110224382B CN110224382B (en) | 2021-08-17 |
Family
ID=67815281
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910570922.9A Active CN110224382B (en) | 2019-06-28 | 2019-06-28 | Micro-grid relay protection method and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110224382B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111244906A (en) * | 2020-01-16 | 2020-06-05 | 浙江浙能技术研究院有限公司 | Micro-grid fault discrimination method based on genetic algorithm |
| CN111983309A (en) * | 2020-08-28 | 2020-11-24 | 武汉鸿阳机电工程有限公司 | Method and device for detecting abnormality of sampling data |
| CN113376466A (en) * | 2021-06-18 | 2021-09-10 | 四川华能宝兴河水电有限责任公司 | Method for checking influence of frequency on sampling of relay protection device |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103956716A (en) * | 2014-05-20 | 2014-07-30 | 上海电气集团股份有限公司 | Micro-grid dynamic self-adapting relay protection method and self-adapting protection device |
| CN105391178A (en) * | 2015-12-24 | 2016-03-09 | 无锡信大气象传感网科技有限公司 | Substation anti-islanding operation monitoring system |
| CN108631353A (en) * | 2017-03-20 | 2018-10-09 | 南京理工大学 | A kind of micro-grid island detection method and system |
| CN108647275A (en) * | 2018-04-28 | 2018-10-12 | 国网北京市电力公司 | The recognition methods of isolated island detecting state and device, storage medium, processor |
| JP2018183034A (en) * | 2017-04-17 | 2018-11-15 | 日新電機株式会社 | Protector for power supply system and system comprising the same |
| CN109523097A (en) * | 2018-12-29 | 2019-03-26 | 杭州电子科技大学 | A kind of more micro-capacitance sensor Optimization Schedulings of improved adaptive GA-IAGA |
-
2019
- 2019-06-28 CN CN201910570922.9A patent/CN110224382B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103956716A (en) * | 2014-05-20 | 2014-07-30 | 上海电气集团股份有限公司 | Micro-grid dynamic self-adapting relay protection method and self-adapting protection device |
| CN105391178A (en) * | 2015-12-24 | 2016-03-09 | 无锡信大气象传感网科技有限公司 | Substation anti-islanding operation monitoring system |
| CN108631353A (en) * | 2017-03-20 | 2018-10-09 | 南京理工大学 | A kind of micro-grid island detection method and system |
| JP2018183034A (en) * | 2017-04-17 | 2018-11-15 | 日新電機株式会社 | Protector for power supply system and system comprising the same |
| CN108647275A (en) * | 2018-04-28 | 2018-10-12 | 国网北京市电力公司 | The recognition methods of isolated island detecting state and device, storage medium, processor |
| CN109523097A (en) * | 2018-12-29 | 2019-03-26 | 杭州电子科技大学 | A kind of more micro-capacitance sensor Optimization Schedulings of improved adaptive GA-IAGA |
Non-Patent Citations (4)
| Title |
|---|
| 严雪飞: "电子负载直流侧电压分析及滤波技术研究", 《理论与方法》 * |
| 余运俊: "滑膜频率偏移法和过/欠频被动法结合的混合孤岛检测法", 《电子测量与仪器学报》 * |
| 张瑞叶: "新型低畸变扰动式孤岛检测法", 《电力系统及其自动化学报》 * |
| 邓超平: "一种新型的微网自适应过流保护方法", 《电力系统保护与控制》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111244906A (en) * | 2020-01-16 | 2020-06-05 | 浙江浙能技术研究院有限公司 | Micro-grid fault discrimination method based on genetic algorithm |
| CN111244906B (en) * | 2020-01-16 | 2021-11-19 | 浙江浙能技术研究院有限公司 | Micro-grid fault discrimination method based on genetic algorithm |
| CN111983309A (en) * | 2020-08-28 | 2020-11-24 | 武汉鸿阳机电工程有限公司 | Method and device for detecting abnormality of sampling data |
| CN113376466A (en) * | 2021-06-18 | 2021-09-10 | 四川华能宝兴河水电有限责任公司 | Method for checking influence of frequency on sampling of relay protection device |
| CN113376466B (en) * | 2021-06-18 | 2022-08-16 | 四川华能宝兴河水电有限责任公司 | Method for checking influence of frequency on sampling of relay protection device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110224382B (en) | 2021-08-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2022160776A1 (en) | Failure analysis method based on relay protection on-line monitoring and analysis system | |
| CN110224382A (en) | Micro-capacitance sensor relay protecting method and device | |
| Zhang et al. | Non-unit traveling wave protection of HVDC grids using Levenberg–Marquart optimal approximation | |
| Chen et al. | A protection scheme for hybrid multi-terminal HVDC networks utilizing a time-domain transient voltage based on fault-blocking converters | |
| CN102195354B (en) | Large-grid wide-area asynchronous coordination control method | |
| CN103618300B (en) | One has highly sensitive HVDC transmission line traveling-wave protection method | |
| CN102611140A (en) | Grid-connected inverter island detection method based on wavelet transform and neural network | |
| CN105119255A (en) | Photovoltaic microgrid fault isolation method based on fault state | |
| CN111999583B (en) | Fault trip judging method of safety and stability control device suitable for alternating current power grid | |
| CN114124728B (en) | Vulnerability coupling link identification method between power grid control system and power primary equipment | |
| CN108132425A (en) | Power grid distribution line failure on-line monitoring method and system | |
| Lin et al. | An adaptive reclosure scheme for parallel transmission lines with shunt reactors | |
| CN104124783A (en) | Electricity fetching device based on electric transmission line aerial thunder prevention ground wires | |
| Diao et al. | Decision tree assisted controlled islanding for preventing cascading events | |
| CN112255499A (en) | Phase current amplitude based power distribution network disconnection fault positioning and identifying method and system | |
| CN103219712A (en) | Power transmission line one-phase malfunction property identification method based on natural frequency | |
| CN109001592A (en) | A kind of resonant earthed system fault line selection method for single-phase-to-ground fault based on transient | |
| CN105262069A (en) | High-voltage DC line pilot protection method based on fault DC component | |
| CN103326384A (en) | Stable emergency control method based on call wire double-peak track | |
| CN109449931A (en) | In conjunction with the cascading failure collection construction method of weighting trend entropy and whole process simulation | |
| Velásquez | Performance improvement in long overhead lines associated to single-phase faults due to atmospheric discharges | |
| Dong et al. | Research on characteristics of voltage fault traveling waves of transmission line | |
| CN202797910U (en) | Standby self-start blocking device in 10kV power distribution room of intelligent substation | |
| CN101958579A (en) | Method of treating information loss in centralized protection device of digitalized substation | |
| Chen et al. | A pilot directional protection based on low frequency voltage variable quantity for LCC-HVDC transmission lines |
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 |