CN110297154A - Earth fault line selection method and device based on zero mould current temporary state energy - Google Patents
Earth fault line selection method and device based on zero mould current temporary state energy Download PDFInfo
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- CN110297154A CN110297154A CN201910650124.7A CN201910650124A CN110297154A CN 110297154 A CN110297154 A CN 110297154A CN 201910650124 A CN201910650124 A CN 201910650124A CN 110297154 A CN110297154 A CN 110297154A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/088—Aspects of digital computing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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Abstract
The invention discloses a kind of earth fault line selection method and device based on zero mould current temporary state energy, the present invention starting link use zero mode voltage, zero mould electric current or Men Qidong, do not influenced by PT broken string；Propose zero mould current temporary state energy balane in fault characteristic band, by using the amplitude size relation between the zero mould current temporary state energy and zero mould and the transient state energy of electric current of each branch, determination is busbar grounding failure or certain grounding failure, route selection link is not necessarily to zero mode voltage amount, also do not influenced by PT broken string, at the same overcome zero mode voltage derivation bring, zero mode voltage, the distributional difference on zero mould current temporary state amount time dimension influences energy harvesting effect；Overcome compensated distribution network power frequency quantity influence route selection accuracy rate the problem of, while this method use zero mould current temporary state amount square when domain integral algorithm, overcome high resistance earthing fault bring under-sensitive problem.
Description
Technical field
The invention belongs to Relay Protection Technology in Power System fields, and in particular to a kind of based on zero mould current temporary state energy
Earth fault line selection method and device.
Background technique
Electric system is according to whether two major classes can be divided by being directly grounded: i.e. neutral-point solid ground (heavy current grounding system)
It is not directly grounded with neutral point (small current neutral grounding system).Neutral point is not directly grounded including isolated neutral system or neutrality
Point flows through the fault current very little of fault point when singlephase earth fault occurs through arc suppression coil (resonance grounding) earthing mode, because
This, also referred to as small current neutral grounding mode.When small current grounding fault occurs for isolated neutral system, there are failure amounts not to protrude
(earth current very little is typically only several amperes), uncertain (arc suppression coil compensation electric current is to power current in resonant earthed system
Influence) and the problems such as unstable (intermittence ground connection with arc grounding incidence height), the own quilt of low-current ground fault line selection technology
The problem being known as in electric system.
To solve this problem of low current neutral grounding system fault route selecting, many scholars have carried out a large amount of research, route selection side
Method is divided into active method and passive means two major classes according to the source of signal used.Active selection method has injecting signal, middle electricity
Resistance method, remnant current increment method, linear perturbation theory etc.；Passive type selection method can be divided into according to the difference of characteristic signal used based on steady
State characteristic quantity be based on two kinds of one of transient characteristic quantity.Wherein the passive type selection method based on steady state information is through grounding through arc
Under system condition, there are ground fault erroneous judgements, are not able to satisfy field demand.There is first half-wave based on one of transient characteristic quantity selection method
Method, transient zero mode current amplitude and polarity comparison, transient zero mode current direction method, transient energy method etc..
Low-current ground fault line selection principle wherein based on zero mould transient state energy is to define zero mould transient energy function
It is integral of the product of zero mode voltage derivative and zero mould electric current in time domain, for faulty line its zero mould transient energy function
Absolute value is greater than the absolute value of healthy line, and zero mould transient energy function value of faulty line is negative value, and healthy line
Zero mould transient energy function value is positive value, to complete the judgement of faulty line.
The existing low-current ground fault line selection principle based on zero mould transient state energy, use zero mode voltage derivative (or
Person is zero mode voltage phase shift) and zero mould electric current integral of the product in time domain, zero mode voltage derivation or zero mode voltage phase shift
It can bring failure that zero mode voltage at moment and the variation of zero mould electric current occurs not in synchronization, 1/4 cycle be differed, to transient state energy
It is unfavorable that the accumulation of amount is brought, and especially in high resistance earthing fault, transient state energy is small and time short only several milliseconds of time windows, route selection
Poor sensitivity influences the correctness of route selection；In addition do not consider that the energy in feature band is accumulated before integral, for warp
For arc suppression coil earthing system in the case where failure initial stage power frequency component accounting is high, route selection False Rate is high.
Summary of the invention
It is an object of the invention to overcome the deficiencies of the prior art and provide a kind of based on the small of zero mould current temporary state energy
Current earthing fault-line selecting method forms complete route selection Technical Solving, is adaptive to isolated neutral system, through disappearing
Arc coil earthed system is influenced through high resistance ground system, and not by PT broken string.
In order to solve the above technical problems, the present invention provides a kind of, the small current neutral grounding based on zero mould current temporary state energy is former
Hinder selection method, characterized in that including following procedure:
Upon the occurrence of a ground fault, zero mould current sample of each branch connected on small current neutral grounding system median generatrix is obtained
Value；
Zero mould electric current of each branch or its variable quantity are filtered, the zero mould electric current for obtaining filtered each branch is temporary
State amount；
It sums to zero mould current temporary state amount of each branch, obtains the transient of zero mould and electric current；
T is carried out to the transient of each zero mould current temporary state amount of branch and zero mould and electric current respectively2Sampled value in time is flat
Fang Jifen obtains zero mould current temporary state energy of each branch and the transient state energy of zero mould and electric current；
T after fault initiating2In time, if the transient state energy of zero mould and electric current is always more than the zero mould electricity of any branch
Flow transient state energy, then it is assumed that busbar grounding failure occurs；If maximum zero mould current temporary state energy is always more than zero mould and electric current
Transient state energy, then it is assumed that this corresponding branch of zero mould current temporary state energy of maximum is the route that ground fault occurs.
Further, judge the criterion of generation ground fault are as follows:
Obtain the zero mould current sampling data and its variable quantity, zero mould of each branch connected on small current neutral grounding system median generatrix
Voltage sample value and its variable quantity；
When zero mode voltage amplitude is more than definite value or zero mode voltage variable quantity amplitude more than definite value, alternatively, any branch route
Zero mould current amplitude is more than definite value or zero mould current change quantity amplitude is more than definite value, then it is assumed that ground fault occurs.
Further, the variation of zero mould current sampling data of each branch connected on the small current neutral grounding system median generatrix
It measures, the variable quantity of zero mode voltage sampled value includes:
Δi0k(t)=i0k(t)-i0k(t-N×ΔT)
Δu0(t)=u0(t)-u0(t-N×ΔT)
Δ T: sampling interval duration；Sampling number in N: one power frequency period；K: kth branch
i0k(t): zero mould current sampling data of current t moment kth branch；
i0k(t-N × Δ T): zero mould current sampling data of the kth branch of the previous cycle of current t moment；
Δi0k(t): the variable quantity of zero mould current sampling data of current t moment kth branch；
u0(t): current zero mode voltage sampled value of t moment bus；
u0(t-N × Δ T): the zero mode voltage sampled value of bus of the previous cycle of current t moment；
Δu0(t): the variable quantity of current zero mode voltage sampled value of t moment bus.
It is further, described that zero mould electric current of each branch or its variable quantity are filtered, specifically:
It is bandpass filtering or wavelet transformation to the filtering mode that zero mould electric current of each branch or its variable quantity are filtered.
Further, T is carried out to the transient of each zero mould current temporary state amount of branch and zero mould and electric current respectively2In time
Sampled value integrated square includes:
Ek_filter(t): the transient state energy under the feature band of corresponding each zero mould electric current of branch
Esum_filter(t): the transient state energy under the feature band of corresponding all zero moulds of branch and electric current
T2: the transient time of integration upper limit under the feature band that failure initial time rises
Δi0k_filterIt (t) is the transient zero mode current transient of kth branch, Δ i0sum_filterIt (t) is zero mould and electric current
Transient.
Correspondingly, the present invention provides a kind of low-current ground fault line selection device based on zero mould current temporary state energy,
It is characterized in that including sampled value acquisition module, zero mould current temporary state amount computing module, zero mould and current temporary state amount computing module；
Transient state energy computing module and failure line selection module；
Sampled value obtains module, upon the occurrence of a ground fault, obtains each connected on small current neutral grounding system median generatrix
The zero mould current sampling data on road；
Zero mould current temporary state amount computing module, is filtered zero mould electric current of each branch or its variable quantity, is filtered
Zero mould current temporary state amount of each branch afterwards；
Zero mould and current temporary state amount computing module sum to zero mould current temporary state amount of each branch, obtain zero mould and
The transient of electric current；
Transient state energy computing module carries out T to the transient of each zero mould current temporary state amount of branch and zero mould and electric current respectively2
Sampled value integrated square in time obtains zero mould current temporary state energy of each branch and the transient state energy of zero mould and electric current；
Failure line selection module, the T after fault initiating2In time, appoint if the transient state energy of zero mould and electric current is always more than
Zero mould current temporary state energy of one branch, then it is assumed that busbar grounding failure occurs；If maximum zero mould current temporary state energy is big always
In the transient state energy of zero mould and electric current, then it is assumed that this corresponding branch of zero mould current temporary state energy of maximum is that ground fault occurs
Route.
Further, sampled value obtains in module, further includes ground fault judgment module, sentences in ground fault judgment module
The disconnected criterion that ground fault occurs are as follows:
Obtain the zero mould current sampling data and its variable quantity, zero mould of each branch connected on small current neutral grounding system median generatrix
Voltage sample value and its variable quantity；
When zero mode voltage amplitude is more than definite value or zero mode voltage variable quantity amplitude more than definite value, alternatively, any branch route
Zero mould current amplitude is more than definite value or zero mould current change quantity amplitude is more than definite value, then it is assumed that ground fault occurs.
Further, sampled value obtains in module, obtains the zero of each branch connected on small current neutral grounding system median generatrix
The variable quantity of mould current sampling data, zero mode voltage sampled value variable quantity include:
Δi0k(t)=i0k(t)-i0k(t-N×ΔT)
Δu0(t)=u0(t)-u0(t-N×ΔT)
Δ T: sampling interval duration；Sampling number in N: one power frequency period；K: kth branch
i0k(t): zero mould current sampling data of current t moment kth branch；
i0k(t-N × Δ T): zero mould current sampling data of the kth branch of the previous cycle of current t moment；
Δi0k(t): the variable quantity of zero mould current sampling data of current t moment kth branch；
u0(t): current zero mode voltage sampled value of t moment bus；
u0(t-N × Δ T): the zero mode voltage sampled value of bus of the previous cycle of current t moment；
Δu0(t): the variable quantity of current zero mode voltage sampled value of t moment bus.
Further, in zero mould current temporary state amount computing module, the zero mould electric current to each branch or its variable quantity into
Row filtering, specifically:
It is bandpass filtering or wavelet transformation to the filtering mode that zero mould electric current of each branch or its variable quantity are filtered.
Further, in transient state energy computing module, respectively to each zero mould current temporary state amount of branch and zero mould and electric current
Transient carries out T2Sampled value integrated square in time includes:
Ek_filter(t): the transient state energy under the feature band of corresponding each zero mould electric current of branch
Esum_filter(t): the transient state energy under the feature band of corresponding all zero moulds of branch and electric current
T2: the transient time of integration upper limit under the feature band that failure initial time rises
Δi0k_filterIt (t) is the transient zero mode current transient of kth branch, Δ i0sum_filterIt (t) is zero mould and electric current
Transient.
Compared with prior art, the beneficial effects obtained by the present invention are as follows being: the present invention uses zero mould electricity in starting link
Pressure, zero mould electric current or Men Qidong, do not influenced by PT broken string；Zero mould in fault characteristic band is proposed in failure line selection link
Current temporary state energy balane, by using between the zero mould current temporary state energy and zero mould and the transient state energy of electric current of each branch
Amplitude size relation, determination is busbar grounding failure or certain grounding failure, overcomes compensated distribution network
Power frequency quantity influence route selection accuracy rate the problem of, while this method use zero mould current temporary state amount square when domain integral calculate
Method overcomes high resistance earthing fault bring under-sensitive problem.Failure line selection is not necessarily to zero mode voltage amount, is not broken by PT
It influences, while overcoming zero mode voltage derivation bring, zero mode voltage, the distributional difference on zero mould current temporary state amount time dimension
Influence energy harvesting effect.
Detailed description of the invention
Fig. 1 is the flow chart of the method for the present invention.
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.
The invention proposes a kind of earth fault line selection methods based on zero mould current temporary state energy, that is, calculate most
Big branch transient zero mode current square when domain integral, calculate all zero moulds of branch transient state and electric current square in time domain inner product
Point, according to amplitude size relation between the two determine fault point in bus or route, when determine belong to line fault when,
This method has both the technical characterstic for being located in which specific line fault simultaneously.
A kind of earth fault line selection method based on zero mould current temporary state energy of the invention, it is shown in Figure 1,
Its process is as follows:
Step 1: the variable quantity of zero mould current sampling data of each branch connected on small current neutral grounding system median generatrix is calculated
Δi0k(t), the variation delta u of zero mode voltage sampled value0(t), to eliminate the influence for operating normally amount of unbalance to subsequent criterion；
Δi0k(t)=i0k(t)-i0k(t-N×ΔT)
Δu0(t)=u0(t)-u0(t-N×ΔT)
Δ T: sampling interval duration；Sampling number in N: one power frequency period；K: kth branch
i0k(t): zero mould current sampling data of current t moment kth branch；
i0k(t-N × Δ T): zero mould current sampling data of the kth branch of the previous cycle of current t moment；
Δi0k(t): the variable quantity of zero mould current sampling data of current t moment kth branch；
u0(t): current zero mode voltage sampled value of t moment bus；
u0(t-N × Δ T): the zero mode voltage sampled value of bus of the previous cycle of current t moment；
Δu0(t): the variable quantity of current zero mode voltage sampled value of t moment bus.
Step 2: when zero mode voltage amplitude is more than definite value or zero mode voltage variable quantity amplitude more than definite value, alternatively, any
Zero mould current amplitude of route road is more than definite value or zero mould current change quantity amplitude is more than definite value, then it is assumed that and ground fault occurs, into
Enter fault initiating link and starts failure line selection；
(U0> U0setOr Δ U0> Δ U0set)||(I0k> I0setOr Δ I0k> Δ I0set)
U0: zero mode voltage amplitude of bus；
ΔU0: according to the zero calculated amplitude of mode voltage sampled value variable quantity of bus in step 1；
U0set: zero mode voltage definite value of bus；
ΔU0set: zero mode voltage variable quantity definite value of bus；
I0k: zero mould current amplitude of kth branch；
ΔI0k: according to the zero calculated amplitude of mould current sampling data variable quantity of kth branch in step 1；
I0set: zero mould current ration；
ΔI0set: zero mould current change quantity definite value.
In the method for the present invention, fault initiating link use zero mode voltage, zero mould electric current or Men Qidong, it is not disconnected by PT
Line influences.
Step 3: to the zero mould current sampling data or variation delta i of each branch0k(t) it is filtered, obtains filtered each
Zero mould current temporary state amount Δ i of a branch0k_filter(t)；
Filtering mode can be bandpass filtering or wavelet transformation, select bandpass filtering mode in the present invention.It can be to zero mould
Current sampling data or its variable quantity are filtered to obtain transient, select variable quantity in the embodiment of the present invention.
It is (the f in characteristic spectra (SFB) since fault branch transient zero mode current is opposite with branch polarity is perfected0, f1) at
Vertical, it is therefore desirable to determine feature band.Wherein low-pass cut-off frequencies f0It is chosen as 3 times of power frequencies, i.e. 150Hz, high pass cutoff frequency
Rate f1For the first resonance frequency of the route survey impedance of system longest outlet.
Δi0k_filter(t)=filter (Δ i0k(t))
Filter: bandpass filtering treatment function
Step 4: to the transient zero mode current transient Δ i of each branch0k_filter(t) it sums, obtains zero mould and electricity
The transient Δ i of stream0sum_filter(t)；
M: route sum
Step 5: T is carried out to the transient of each zero mould current temporary state amount of branch and zero mould and electric current respectively2Adopting in the time
Sample value integrated square obtains zero mould current temporary state energy of each branch and the transient state energy of zero mould and electric current；
Ek_filter(t): the transient state energy under the feature band of corresponding each zero mould electric current of route
Esum_filter(t): the transient state energy under the feature band of corresponding all zero moulds of route and electric current
T2: the transient time of integration upper limit under the feature band that failure initial time rises
T2Size is 1/f0, the 1/3 cycle time, to guarantee that zero mould current temporary state energy balane at least embodies high fdrequency component
The transient of one complete cycle.
Step 6: the T after fault initiating2In time, if the transient state energy of zero mould and electric current is always more than any branch
Zero mould current temporary state energy, then it is assumed that occur busbar grounding failure；If maximum zero mould current temporary state energy is always more than zero mould
With the transient state energy of electric current, then it is assumed that this corresponding branch of zero mould current temporary state energy of maximum is the route that ground fault occurs.
Formula expression are as follows:
In 0~T2, it is all satisfied Esum_filter(t) > k1×max(Ek_filter(t)), then ground fault occurs for bus
In 0~T2, it is all satisfied Ek_filter(t) > k2Esum_filterAnd E (t),k_filterIt (t) is transient state energy maximum branch,
Then ground fault occurs for kth branch
k1、k2For safety factor, max (Ek_filterIt (t)) is the zero mould current temporary state energy of maximum sought in all branches
Function
Wherein k1、k2Value 2.
The T it is found that after fault initiating is described from above formula2In time, the transient state energy of zero mould and electric current is big always
In maximum zero mould current temporary state energy (the zero mould current temporary state energy for being corresponding to greater than any branch), then it is assumed that bus occurs
Ground fault；If the zero mould current temporary state energy that zero mould current temporary state energy of certain branch is greater than other all branches (is equivalent to
Maximum zero mould current temporary state energy), and also it is always more than the transient state energy of zero mould and electric current, then it is assumed that branch has occurred and connects
Earth fault, this branch are the route that ground fault occurs.
The present invention proposes zero mould current temporary state energy balane in fault characteristic band in failure line selection link, by adopting
With the amplitude size relation between the zero mould current temporary state energy and zero mould and the transient state energy of electric current of each branch, determination is female
Line ground fault or certain grounding failure, overcoming compensated distribution network power frequency quantity influences asking for route selection accuracy rate
Topic, at the same this method use zero mould current temporary state amount square when domain integral algorithm, overcome high resistance earthing fault band
The under-sensitive problem come.Failure line selection is not necessarily to zero mode voltage amount, is not influenced by PT broken string, while overcoming zero mode voltage
Distributional difference in zero mode voltage of derivation bring, zero mould current temporary state amount time dimension influences energy harvesting effect.
Correspondingly, the present invention provides a kind of low-current ground fault line selection device based on zero mould current temporary state energy,
It is characterized in that including sampled value acquisition module, zero mould current temporary state amount computing module, zero mould and current temporary state amount computing module；
Transient state energy computing module and failure line selection module；
Sampled value obtains module, upon the occurrence of a ground fault, obtains each connected on small current neutral grounding system median generatrix
The zero mould current sampling data on road；
Zero mould current temporary state amount computing module, is filtered zero mould current change quantity of each branch or its variable quantity, obtains
To zero mould current temporary state amount of filtered each branch；
Zero mould and current temporary state amount computing module sum to zero mould current temporary state amount of each branch, obtain zero mould and
The transient of electric current；
Transient state energy computing module carries out T to the transient of each zero mould current temporary state amount of branch and zero mould and electric current respectively2
Sampled value integrated square in time obtains zero mould current temporary state energy of each branch and the transient state energy of zero mould and electric current；
Failure line selection module, the T after fault initiating2In time, appoint if the transient state energy of zero mould and electric current is always more than
Zero mould current temporary state energy of one branch, then it is assumed that busbar grounding failure occurs；If maximum zero mould current temporary state energy is big always
In the transient state energy of zero mould and electric current, then it is assumed that this corresponding branch of zero mould current temporary state energy of maximum is that ground fault occurs
Route.
Further, sampled value obtains in module, further includes ground fault judgment module, sentences in ground fault judgment module
The disconnected criterion that ground fault occurs are as follows:
Obtain the zero mould current sampling data and its variable quantity, zero mould of each branch connected on small current neutral grounding system median generatrix
Voltage sample value and its variable quantity；
When zero mode voltage amplitude is more than definite value or zero mode voltage variable quantity amplitude more than definite value, alternatively, any branch route
Zero mould current amplitude is more than definite value or zero mould current change quantity amplitude is more than definite value, then it is assumed that ground fault occurs.
Further, sampled value obtains in module, obtains the zero of each branch connected on small current neutral grounding system median generatrix
The variable quantity of mould current sampling data, zero mode voltage sampled value variable quantity include:
Δi0k(t)=i0k(t)-i0k(t-N×ΔT)
Δu0(t)=u0(t)-u0(t-N×ΔT)
Δ T: sampling interval duration；Sampling number in N: one power frequency period；K: kth branch
i0k(t): zero mould current sampling data of current t moment kth branch；
i0k(t-N × Δ T): zero mould current sampling data of the kth branch of the previous cycle of current t moment；
Δi0k(t): the variable quantity of zero mould current sampling data of current t moment kth branch；
u0(t): current zero mode voltage sampled value of t moment bus；
u0(t-N × Δ T): the zero mode voltage sampled value of bus of the previous cycle of current t moment；
Δu0(t): the variable quantity of current zero mode voltage sampled value of t moment bus.
Further, in zero mould current temporary state amount computing module, filtering mode is bandpass filtering or wavelet transformation.
Further, in transient state energy computing module, respectively to each zero mould current temporary state amount of branch and zero mould and electric current
Transient carries out T2Sampled value integrated square in time includes:
Ek_filter(t): the transient state energy under the feature band of corresponding each zero mould electric current of branch
Esum_filter(t): the transient state energy under the feature band of corresponding all zero moulds of branch and electric current
T2: the transient time of integration upper limit under the feature band that failure initial time rises
Δi0k_filterIt (t) is the transient zero mode current transient of kth branch, Δ i0sum_filterIt (t) is zero mould and electric current
Transient.
Compared with prior art, the beneficial effects obtained by the present invention are as follows being:
Using the transient in all zero moulds of route and failure of the current feature band, theoretically connect in line fault
It is bordering on 0, in bus-bar fault, for the summation of the transient in all zero mould current failure feature bands of route, always greater than most
Transient in zero mould current failure feature band of big route, and discrimination is obvious；
Power frequency component is eliminated, together in this frequency band using the transient energy method in zero mould current failure feature band
When this frequency band in inductive current in compensated distribution network be much smaller than branch capacitive earth current, eliminate and sell camber line
Enclosing stable state power frequency component in earthed system influences bring erroneous judgement to energy accumulation；
Start that link uses zero mode voltage and zero mould electric current or Men Qidong, route selection link and uses zero mould current temporary state
The integral of amount square in the time domain, is not necessarily to zero mode voltage amount, and this method is not influenced by PT broken string；
Route selection link is not necessarily to zero mode voltage amount, overcomes zero mode voltage derivation bring, zero mode voltage, zero mould current temporary state
The distributional difference measured on time dimension influences energy harvesting effect；
Using the integral of zero mould current squaring in the time domain in feature band, high resistance earthing fault bring spirit is overcome
The insufficient influence of sensitivity；
It is not influenced by arc suppression coil earthing system in the principle of the invention, isolated neutral system is adaptive in method
System, compensated distribution network, through high resistance ground system, have wide range of applications, and be not present route selection blind area.
It should be understood by those skilled in the art that, embodiments herein can provide as method, system or computer program
Product.Therefore, complete hardware embodiment, complete software embodiment or reality combining software and hardware aspects can be used in the application
Apply the form of example.Moreover, it wherein includes the computer of computer usable program code that the application, which can be used in one or more,
The computer program implemented in usable storage medium (including but not limited to magnetic disk storage, CD-ROM, optical memory etc.) produces
The form of product.
The application is referring to method, the process of equipment (system) and computer program product according to the embodiment of the present application
Figure and/or block diagram describe.It should be understood that every one stream in flowchart and/or the block diagram can be realized by computer program instructions
The combination of process and/or box in journey and/or box and flowchart and/or the block diagram.It can provide these computer programs
Instruct the processor of general purpose computer, special purpose computer, Embedded Processor or other programmable data processing devices to produce
A raw machine, so that being generated by the instruction that computer or the processor of other programmable data processing devices execute for real
The device for the function of being specified in present one or more flows of the flowchart and/or one or more blocks of the block diagram.
These computer program instructions, which may also be stored in, is able to guide computer or other programmable data processing devices with spy
Determine in the computer-readable memory that mode works, so that it includes referring to that instruction stored in the computer readable memory, which generates,
Enable the manufacture of device, the command device realize in one box of one or more flows of the flowchart and/or block diagram or
The function of being specified in multiple boxes.
These computer program instructions also can be loaded onto a computer or other programmable data processing device, so that counting
Series of operation steps are executed on calculation machine or other programmable devices to generate computer implemented processing, thus in computer or
The instruction executed on other programmable devices is provided for realizing in one or more flows of the flowchart and/or block diagram one
The step of function of being specified in a box or multiple boxes.
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 improvements and modifications, these improvements and modifications can also be made
Also it should be regarded as protection scope of the present invention.
Claims (10)
1. a kind of earth fault line selection method based on zero mould current temporary state energy, characterized in that including following procedure:
Upon the occurrence of a ground fault, zero mould current sampling data of each branch connected on small current neutral grounding system median generatrix is obtained；
Zero mould electric current of each branch or its variable quantity are filtered, zero mould current temporary state of filtered each branch is obtained
Amount；
It sums to zero mould current temporary state amount of each branch, obtains the transient of zero mould and electric current；
T is carried out to the transient of each zero mould current temporary state amount of branch and zero mould and electric current respectively2Sampled value square product in time
Point, obtain zero mould current temporary state energy of each branch and the transient state energy of all branches zero mould and electric current；
T after fault initiating2In time, if the zero mould electric current that the transient state energy of zero mould and electric current is always more than any branch is temporary
State energy, then it is assumed that busbar grounding failure occurs；If maximum zero mould current temporary state energy is always more than the transient state of zero mould and electric current
Energy, then it is assumed that this corresponding branch of zero mould current temporary state energy of maximum is the route that ground fault occurs.
2. a kind of earth fault line selection method based on zero mould current temporary state energy according to claim 1,
It is characterized in, the criterion that ground fault occurs are as follows:
Obtain the zero mould current sampling data and its variable quantity, zero mode voltage of each branch connected on small current neutral grounding system median generatrix
Sampled value and its variable quantity；
When zero mode voltage amplitude is more than definite value or zero mode voltage variable quantity amplitude more than definite value, alternatively, any zero mould of branch route
Current amplitude is more than definite value or zero mould current change quantity amplitude is more than definite value, then it is assumed that ground fault occurs.
3. a kind of earth fault line selection method based on zero mould current temporary state energy according to claim 1,
It is characterized in, variable quantity, the zero mould electricity of zero mould current sampling data of each branch connected on the small current neutral grounding system median generatrix
Pressure sampled value variable quantity include:
Δi0k(t)=i0k(t)-i0k(t-N×ΔT)
Δu0(t)=u0(t)-u0(t-N×ΔT)
Δ T: sampling interval duration；Sampling number in N: one power frequency period；K: kth branch
i0k(t): zero mould current sampling data of current t moment kth branch；
i0k(t-N × Δ T): zero mould current sampling data of the kth branch of the previous cycle of current t moment；
Δi0k(t): the variable quantity of zero mould current sampling data of current t moment kth branch；
u0(t): current zero mode voltage sampled value of t moment bus；
u0(t-N × Δ T): the zero mode voltage sampled value of bus of the previous cycle of current t moment；
Δu0(t): the variable quantity of current zero mode voltage sampled value of t moment bus.
4. a kind of earth fault line selection method based on zero mould current temporary state energy according to claim 1,
It is characterized in, it is described that zero mould electric current of each branch or its variable quantity are filtered, specifically:
It is bandpass filtering or wavelet transformation to the filtering mode that zero mould electric current of each branch or its variable quantity are filtered.
5. a kind of earth fault line selection method based on zero mould current temporary state energy according to claim 1,
It is characterized in, it is described that T is carried out to the transient of each zero mould current temporary state amount of branch and zero mould and electric current respectively2Sampled value in time
Integrated square includes:
Ek_filter(t): the transient state energy under the feature band of corresponding each zero mould electric current of branch
Esum_filter(t): the transient state energy under the feature band of corresponding all zero moulds of branch and electric current
T2: the transient time of integration upper limit under the feature band that failure initial time rises
Δi0k_filterIt (t) is zero mould current temporary state amount of kth branch, Δ i0sum_filter(t) be zero mould and electric current transient.
6. a kind of low-current ground fault line selection device based on zero mould current temporary state energy, characterized in that obtained including sampled value
Modulus block, zero mould current temporary state amount computing module, zero mould and current temporary state amount computing module；Transient state energy computing module and failure
Route selection module；
Sampled value obtains module, upon the occurrence of a ground fault, obtains each for calculating and connecting on small current neutral grounding system median generatrix
The zero mould current sampling data on road；
Zero mould current temporary state amount computing module, is filtered zero mould electric current of each branch or its variable quantity, obtains filtered
Zero mould current temporary state amount of each branch；
Zero mould and current temporary state amount computing module sum to zero mould current temporary state amount of each branch, obtain zero mould and electric current
Transient；
Transient state energy computing module carries out T to the transient of each zero mould current temporary state amount of branch and zero mould and electric current respectively2Time
Interior sampled value integrated square obtains zero mould current temporary state energy of each branch and the transient state energy of zero mould and electric current；
Failure line selection module, the T after fault initiating2In time, if the transient state energy of zero mould and electric current is always more than any branch
Zero mould current temporary state energy, then it is assumed that occur busbar grounding failure；If maximum zero mould current temporary state energy is always more than zero mould
With the transient state energy of electric current, then it is assumed that this corresponding branch of zero mould current temporary state energy of maximum is the route that ground fault occurs.
7. a kind of low-current ground fault line selection device based on zero mould current temporary state energy according to claim 6,
It is characterized in, sampled value obtains in module, further includes ground fault judgment module, ground fault occurs in ground fault judgment module
Criterion are as follows:
Obtain the zero mould current sampling data and its variable quantity, zero mode voltage of each branch connected on small current neutral grounding system median generatrix
Sampled value and its variable quantity；
When zero mode voltage amplitude is more than definite value or zero mode voltage variable quantity amplitude more than definite value, alternatively, any zero mould of branch route
Current amplitude is more than definite value or zero mould current change quantity amplitude is more than definite value, then it is assumed that ground fault occurs.
8. a kind of low-current ground fault line selection device based on zero mould current temporary state energy according to claim 6,
It is characterized in, sampled value obtains in module, zero mould current sample of each branch connected on the small current neutral grounding system median generatrix
The variable quantity of value, zero mode voltage sampled value variable quantity include:
Δi0k(t)=i0k(t)-i0k(t-N×ΔT)
Δu0(t)=u0(t)-u0(t-N×ΔT)
Δ T: sampling interval duration；Sampling number in N: one power frequency period；K: kth branch
i0k(t): zero mould current sampling data of current t moment kth branch；
i0k(t-N × Δ T): zero mould current sampling data of the kth branch of the previous cycle of current t moment；
Δi0k(t): the variable quantity of zero mould current sampling data of current t moment kth branch；
u0(t): current zero mode voltage sampled value of t moment bus；
u0(t-N × Δ T): the zero mode voltage sampled value of bus of the previous cycle of current t moment；
Δu0(t): the variable quantity of current zero mode voltage sampled value of t moment bus.
9. a kind of low-current ground fault line selection device based on zero mould current temporary state energy according to claim 6,
It is characterized in, it is described that zero mould electric current of each branch or its variable quantity are filtered in zero mould current temporary state amount computing module, specifically
Are as follows:
It is bandpass filtering or wavelet transformation to the filtering mode that zero mould electric current of each branch or its variable quantity are filtered.
10. a kind of low-current ground fault line selection device based on zero mould current temporary state energy according to claim 6,
It is characterized in, it is described respectively to the transient of each branch zero mould current temporary state amount and zero mould and electric current in transient state energy computing module
Carry out T2Sampled value integrated square in time includes:
Ek_filter(t): the transient state energy under the feature band of corresponding each zero mould electric current of route
Esum_filter(t): the transient state energy under the feature band of corresponding all zero moulds of route and electric current
T2: the transient time of integration upper limit under the feature band that failure initial time rises
Δi0k_filterIt (t) is the transient zero mode current transient of kth branch, Δ i0sum_filter(t) be zero mould and electric current transient state
Amount.
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