CN108776283A - A kind of CT not exclusively lower power distribution network single-phase disconnection fault judgment method of configuration with judge system - Google Patents
A kind of CT not exclusively lower power distribution network single-phase disconnection fault judgment method of configuration with judge system Download PDFInfo
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Abstract
The invention discloses a kind of CT not exclusively lower power distribution network single-phase disconnection fault judgment methods of configuration with judge system, which includes fault initiating criterion and disconnection fault detection criteria；The judgement system is made of current/voltage conversion module, voltage/voltage change module, working power module, D/A converter module, data calculation processing module, control module, On-off signal output module, communication interface modules and human-computer interaction module；Present invention introduces voltages and the magnitude of current to collectively form disconnection fault criterion; the situation of change of each phase current and voltage can be considered; disconnection fault judgement can not only be carried out in the case where CT is not exclusively configured; and can it is reliable, accurately distinguish situations such as disconnection fault and CT broken strings, dissymmetrical load, it is ensured that the reliability of disconnection fault Protection criteria.
Description
Technical field
The present invention relates to electric device maintenance technical field, the power distribution network under specifically a kind of CT not exclusively configurations is single-phase
Disconnection fault judgment method and judge system.
Background technology
Taking place frequently for distribution line disconnection fault gradually causes the attention of people.Both at home and abroad have several documents for
Electrical quantity caused by distribution line disconnection fault changes, the variation characteristic of especially each order components has carried out theory analysis, summarizes
The changing rule of related electric amount；There is document to propose to carry out the side of disconnection fault judgement and positioning based on negative-sequence current component
Method, but the case where generally existing CT is not exclusively configured in power distribution network, the acquisition and calculating of negative sequence component have greater limitations；
There is document to propose that disconnection fault based on wavelet transformation judges and localization method, but such to data sampling frequency and calculating at
Reason precision has higher requirements, and is not suitable for being widely applied in power distribution network.
Dedicated disconnection fault protective device is not equipped in current power distribution network.After disconnection fault occurs, line current
There are very big difference, the short circuit that traditional kinetic current increases, voltage reduces to protect when with the changing rule and short trouble of busbar voltage
Shield principle and device simultaneously can not provide sensitive, reliable defencive function for disconnection fault, without corresponding after disconnection fault occurs
Safeguard measure, there is the risks to operate with failure for power grid.In addition, it is contemplated that power distribution network is not exclusively matched using CT at present
It sets, is that two phase configuration CT, B phase of A, C is unworthy of that in the case of CT complete three-phase current can not be provided under normal circumstances, it is assumed that hair
A phase disconnection faults are given birth to, A phase currents are reduced to 0 by normal load current at this time, if it is considered that power distribution network branch, A phase currents
It will not be reduced to 0, but can be obviously reduced.C phase currents can also reduce, but the unobvious reduced, and minimum is reduced to normal duty electric currentTimes.Break in case of C phases, obtained curent change rule is similar when breaking with A phases.Electric current is relied solely at this time
Amount constitutes criterion and is unable to ensure the reliability judged disconnection fault, because if dissymmetrical load, A phases or C phases has occurred
CT disconnection faults situations such as, the changing rule of the magnitude of current is also similar, the above situation is easily mistaken for single-phase wire break therefore
Barrier.It is therefore desirable to propose the power distribution network single-phase disconnection breakdown judge system and method under a kind of consideration CT is not exclusively configured, it is
Power distribution network provides sensitive, reliable disconnection fault defencive function.
Invention content
To solve the above problems, the object of the present invention is to provide the power distribution network single-phase disconnection events under a kind of CT not exclusively configuration
Hinder judgment method and judges system.
The present invention to achieve the above object, is achieved through the following technical solutions：
Power distribution network single-phase disconnection fault judgment method under a kind of CT not exclusively configuration, including fault initiating criterion and broken string
Fault detect criterion；
Wherein fault initiating criterion is
In formula, Δ iφFor the variable quantity of A phases or C phase current sampling values,WithIt is mutually current for A phases or C phases
The current sampling data at moment before moment and 1 power frequency period,For to continuous k | iφ| summation, 1<K≤N/2, INFor
Circuit rated current virtual value, ksetTo adjust threshold value coefficient, ksetNumerical value be 0.1~0.2；
Disconnection fault detection criteria includes B phase disconnection faults criterion, A phases or C phase disconnection fault criterions；
Wherein B phases disconnection fault criterion is
Wherein,Expression takes A phase currents and C phase current magnitude the greater；Expression takes A
Phase current and C phase current magnitude smallers；Indicate the phase difference of A phase currents and C phase currents；It indicates
Take A phase voltages and C phase voltage amplitude smallers；
A phases or C phase disconnection fault criterions are
Wherein,Expression takes A phase currents and C phase current magnitude the greater；Expression takes A
Phase current and C phase current magnitude smallers；Expression takes A phase voltages and C phase voltage amplitude the greater；Expression takes A phase voltages, B phase voltages and C phase voltage amplitude smallers.
Power distribution network single-phase disconnection fault judgment method under a kind of preferred CT not exclusively configurations, includes the following steps：
1. broken wire protecting equipment constantly detects A phases and C phase currents in normal operation, when any phase current sampling amount of the two
When meeting fault initiating criterion, breaking protection starts, and enters step 2.；
2. judging the size of A phases and C phase currents, the smaller value of higher value of the two is then used, judges whether ratio is more than
1.2, it enters step 3., is otherwise entered step 4. if it is greater than 1.2；
3. if A phase currents are more than C phase currents, with voltage magnitude smaller in C phase voltages Amplitude Ration A phases and B phases, sentence
Whether disconnected ratio is more than 1.2, if it is greater than 1.2, shows that C phase disconnection faults have occurred, and otherwise that disconnection fault does not occur, terminates
Flow；Equally, if C phase currents are more than A phase currents, with voltage magnitude smaller in A phase voltages Amplitude Ration B phases and C phases, sentence
Whether disconnected ratio is more than 1.2, if it is greater than 1.2, shows that A phase disconnection faults have occurred, and otherwise that disconnection fault does not occur, terminates
Flow；
4. judging that the difference of A phase currents and C phase angle of phase current whether between [130 °, 180 °], then uses B phase voltages
Voltage magnitude smaller in A phases and C phases on Amplitude Ration, judges whether ratio is more than 1.2；If conditions above meets simultaneously, table
Bright B phases disconnection fault terminates flow otherwise that disconnection fault does not occur.
Preferably, ksetNumerical value be 0.15.
The invention also includes the power distribution network single-phase disconnection breakdown judge systems under a kind of CT not exclusively configuration, by electric current/electricity
Press conversion module, voltage/voltage change module, working power module, D/A converter module, data calculation processing module, control
Module, On-off signal output module, communication interface modules and human-computer interaction module composition, wherein D/A converter module respectively with
Current/voltage conversion module, voltage/voltage change module are connected with data calculation processing module, control module respectively with data
Calculation processing module, human-computer interaction module, communication interface modules are connected with On-off signal output module.
Preferably, the current signal of input only has A phases and C phase currents, and the information of voltage of input is A, B, C three-phase voltage.
Current signal is converted to suitable microsystem by current/voltage conversion module, voltage signal through overvoltage/voltage transformation module
The weak voltage signal of work and processing, peak-to-peak value are ± 5V~± 15V；Above-mentioned weak voltage signal is handled by D/A converter module
Become discrete digital signal afterwards, then calculated and handled by data calculation processing module, completes the amplitude of voltage, electric current
With the calculating of phase；
Control module carries out logical comparison and judgement to the result of calculation from data calculation processing module, judges current
Whether electrical magnitude relation meets criterion.If meeting criterion, disconnection fault has occurred in circuit where showing, controls On-off signal
Output module sends out trip signal, controls circuit breaker trip；If being unsatisfactory for criterion, show that broken string event does not occur for protected circuit
Barrier, broken wire protecting equipment are failure to actuate；
On-off signal output module is acted on by control module, can send out trip signal and alarm signal；Also it can receive
From external circuit breaker position status signal or other switching value information；
Working power module provides the direct-current working volts of different amplitudes for entire protective device；
Human-computer interaction module includes keyboard and liquid crystal display, for completing basic human-computer interaction function；
Communication interface modules is used for completing the information exchange function between broken wire protecting equipment and electric substation automation system,
Broken wire protecting equipment needs measurement, calculating and criterion result being uploaded to electric substation automation system, it is also desirable to receive from change
The various telecommands of power station automation system.
Preferably, peak-to-peak value is ± 10V.
Preferably, data calculation processing module is the dsp chip of TMS320 series.
Preferably, control module is STM32F type singlechip chips.
Preferably, the direct-current working volts of different amplitudes are 220V, ± 12V, 5V and 3.3V.
The present invention has the following advantages compared with prior art：
The principle of the invention understands, it is easy to accomplish, it need not additionally increase equipment, it is at low cost, do not increase operating maintenance work
Amount, the present invention by disconnection fault protection according to fault initiating criterion and disconnection fault detection criteria is divided into, sentence by wherein fault initiating
According to sufficiently high sensitivity, start-up criterion when non-disconnection fault is allowed to act, but do not allow not start when disconnection fault.Therefore
Enter disconnection fault detection criteria after hindering start-up criterion action, the requirement to the criterion is that have higher reliability, Neng Gouke
By distinguishing disconnection fault and non-disconnection fault, to improve the reliability that the lower disconnection fault of CT not exclusively configurations judges, the present invention draws
Enter voltage and collectively form disconnection fault criterion with the magnitude of current, the situation of change of each phase current and voltage can be considered, no
Can only carry out disconnection fault judgement in the case where CT is not exclusively configured, and can it is reliable, accurately distinguish disconnection fault and
Situations such as CT broken strings, dissymmetrical load, it is ensured that the reliability of disconnection fault Protection criteria.
Description of the drawings
Fig. 1 is the flow chart of the power distribution network single-phase disconnection fault judgment method under CT not exclusively configurations；
Fig. 2 is the distribution net work structure schematic diagram of typical 10kV systems；
Fig. 3 is the changing rule schematic diagram of each phase current before and after the failure under CT not exclusively configurations；
Fig. 4 is voltage change curve schematic diagram at A；
Fig. 5 is voltage change curve schematic diagram at B；
Fig. 6 is the structure connection diagram of the power distribution network single-phase disconnection breakdown judge system under CT not exclusively configurations.
Specific implementation mode
The object of the present invention is to provide a kind of CT not exclusively lower power distribution network single-phase disconnection fault judgment methods of configuration with sentence
Disconnected system, is achieved through the following technical solutions：
The incomplete configuring conditions of CT of power distribution network refer to that A phases are equipped with CT with C phases, and B phases are not equipped with CT, so being filled to protection
For setting equal secondary devices, the electric current of A phases and C phases can only be obtained, B phase currents can not be obtained.For busbar PT, one is well matched
For three-phase five-limb PT, it is capable of providing complete A, B, C three-phase voltage and residual voltage.The present invention is based on above-mentioned mutual inductors to match
It sets situation and corresponding electrical quantity proposes corresponding single-phase wire break Protection criteria.
Assuming that A phase disconnection faults have occurred, A phase currents are reduced to 0 by normal load current at this time, if it is considered that distribution
Branch is netted, A phase currents will not be reduced to 0, but can be obviously reduced.C phase currents can also reduce, but the unobvious reduced, minimum are reduced to
Normal duty electric currentTimes.Break in case of C phases, obtained curent change rule is similar when breaking with A phases.This
When rely solely on the magnitude of current constitute criterion be unable to ensure the reliability judged disconnection fault, because if it is not right that load has occurred
Situations such as CT disconnection faults of title, A phases or C phases, the changing rule of the magnitude of current is also similar, easily judges the above situation by accident
For single-phase wire break failure.To improve the reliability that the lower disconnection fault of CT not exclusively configurations judges, present invention introduces voltages, with electricity
Flow collectively forms disconnection fault criterion.
When A phase disconnection faults occur, according to the changing rule of voltage it is found that A phase voltages can be significantly raised at this time,
Two non-faulting phase voltages of remaininging can reduce, and the residual voltage of certain amplitude occurs in system.And when A phase CT disconnection faults occur, it is
System three-phase voltage almost symmetry, residual voltage amplitude will not be very big；When situation asymmetric there are three-phase load, although having
The residual voltage of certain amplitude, but amplitude still will not be very big, and system three-phase voltage is in symmetry status substantially.As it can be seen that synthesis is examined
Consider the situation of change of each phase current and voltage, disconnection fault judgement can not only be carried out in the case where CT is not exclusively configured, and
And can it is reliable, accurately distinguish situations such as disconnection fault and CT broken strings, dissymmetrical load, it is ensured that disconnection fault Protection criteria
Reliability.
When C phase disconnection faults occur, respective electric amount in addition to separate different, changing rule be it is identical, no longer
It repeats.
When B phase disconnection faults occur, the electric current of A phases and C phases can slightly reduce, but phase difference will increase；Three-phase voltage
In an at least phase (failure phase) can be significantly raised, remaining two-phase can decrease, and the residual voltage of certain amplitude occurs.
To sum up：When non-B phases disconnection fault, faulted phase current can be obviously reduced, and another phase current can slightly reduce；B phases are broken
When line failure, biphase current slightly reduces, but phase difference will increase.No matter which mutually breaks, and broken string is had in three-phase voltage
Mutually significantly raised, in addition two-phase slightly reduces, and will appear the residual voltage of certain amplitude.
Disconnection fault Protection criteria includes two parts：First part is fault initiating criterion, and second part is disconnection fault
Detection criteria.Wherein, the requirement of fault initiating criterion is that have sufficiently high sensitivity, start-up criterion when allowing non-disconnection fault
Action, but do not allow not start when disconnection fault.Enter disconnection fault detection criteria after the action of fault initiating criterion, to the criterion
Requirement be that there is higher reliability, can reliably distinguish disconnection fault and non-disconnection fault.
Start-up criterion：
In formula,For the variable quantity of A phases or C phase current sampling values,WithFor A phases or current C phases when
The current sampling data at moment before quarter and 1 power frequency period,For to continuous kSummation, 1<K≤N/2, INFor
Circuit rated current virtual value, ksetTo adjust threshold value coefficient, 0.1~0.2 can use based on experience value.
First condition is kinetic current reduction in start-up criterion expression formula, and second condition requires the amplitude of current reduction
Reach certain requirement, while starting breaking protection after meeting the two conditions.
For start-up criterion, it is important that the sensitivity that have enough is ensured, as long as therefore there is current value reduction
Situation can all meet the entry condition of breaking protection, as to whether disconnection fault really occurs, comparing for disconnection fault occurs etc.
Concrete condition needs to further discriminate between by disconnection fault detection criteria.
Disconnection fault detection criteria：
For B phase disconnection faults, criterion is：
In formula,Expression takes A phase currents and C phase current magnitude the greater；Expression takes A
Phase current and C phase current magnitude smallers；Indicate the phase difference of A phase currents and C phase currents；It indicates
Take A phase voltages and C phase voltage amplitude smallers.Ratio threshold value 1.2 determines based on experience value, 130 ° and 180 ° of range according to
Theory analysis and result of calculation determine jointly.
When B phase disconnection faults occur, A, C biphase current can reduce, therefore breaking protection start-up criterion can reliably start.
A, C biphase current amplitude are substantially suitable at this time, therefore can meet first current amplitude ratio criterion；A, C biphase currents phase
Difference will increase, and be up to 180 °, therefore can meet second current and phase difference criterion；B phase voltages can increase at this time, A, C two-phase
Voltage at least one is met reduction, therefore can meet third voltage magnitude ratio criterion.
Break for A phases or C phases, criterion is：
In formula,Expression takes A phase currents and C phase current magnitude the greater；Expression takes A
Phase current and C phase current magnitude smallers；Expression takes A phase voltages and C phase voltage amplitude the greater；Expression takes A phase voltages, B phase voltages and C phase voltage amplitude smallers.Ratio threshold value 1.2 is according to warp
Test value determination.
When A phases or C phase disconnection faults occurs, faulted phase current can be obviously reduced, therefore breaking protection start-up criterion energy
Enough reliable startups.Non-faulting phase current is larger compared to for fault current at this time, therefore the ratio of the two amplitude also can be larger, full
First current amplitude ratio criterion of foot；At this time faulted phase voltage increase, remaining two non-faulting phase voltage at least one can drop
It is low, therefore faulted phase voltage and the ratio of non-faulting phase voltage minimum value also can be larger, meet second amplitude voltage ratio and sentence
According to.
Impact analysis of the irregular operating state to above-mentioned criterion：
1) CT breaks：The electrical quantity variation characteristic of secondary side has similarity with line disconnection failure when CT breaks, but
In the presence of apparent difference.When CT breaks, broken string phase current is obviously reduced or becomes 0, can meet disconnection fault start-up criterion, also may be used
It can meet the ratio criterion of current amplitude, but the amplitude of non-faulting phase current and phase difference are constant at this time, and three-phase voltage base
This is in symmetry status, therefore will not meet non-faulting phase current phase angle difference criterion, will not meet voltage magnitude ratio criterion,
CT can be broken accordingly and reliably be distinguished with line disconnection failure.In addition, occurring to generally result in when line disconnection failure more
Similar variation occurs simultaneously for the electric current of a measuring point, and the electric current that CT broken strings only result in certain point changes, hereby it is possible to not
The CT broken strings and line disconnection failure of the complete mode of connection further discriminate between.
2) open-phase operation：In power distribution network, the open-phase operation of circuit is by switching manipulation mostly in addition to disconnection fault
It is caused.The switch of power distribution network is substantially three-phase operation, is generally not in prolonged non-full-operating state.If by
Lead to circuit long-time open-phase operation in reasons such as switch faults, can be considered disconnection fault.For short time open-phase operation
State, action delay appropriate can be arranged, and breaking protection caused by escape the possibility of open-phase operation in short-term is judged by accident.
3) out-of-balance load：Dissymmetrical load is mostly to easily occur in load branched line caused by due to single-phase electricity consumption
On.When three-phase load asymmetry reaches a certain level, three-phase current will appear feature similar with disconnection fault, but bear
System three-phase voltage still almost symmetry when lotus asymmetry will not meet above-mentioned voltage magnitude ratio criterion, accordingly can be with area
Divide out-of-balance load operation and single-phase wire break failure.
Below in conjunction with specific embodiment, the invention will be further described.
Embodiment 1
The flow chart of power distribution network single-phase disconnection fault judgment method under CT as shown in Figure 1 not exclusively configuration, including with
Lower step：
1. broken wire protecting equipment constantly detects A phases and C phase currents in normal operation, when any phase current sampling amount of the two
When meeting fault initiating criterion, breaking protection starts, and enters step 2. disconnection fault and judges flow；
2. judging the size of A phases and C phase currents, the smaller value of higher value of the two is then used, judges whether ratio is more than
1.2, it enters step 3., is otherwise entered step 4. if it is greater than 1.2；
3. if A phase currents are more than C phase currents, with voltage magnitude smaller in C phase voltages Amplitude Ration A phases and B phases, sentence
Whether disconnected ratio is more than 1.2, if it is greater than 1.2, shows that C phase disconnection faults have occurred, and otherwise that disconnection fault does not occur, terminates
Flow；Equally, if C phase currents are more than A phase currents, with voltage magnitude smaller in A phase voltages Amplitude Ration B phases and C phases, sentence
Whether disconnected ratio is more than 1.2, if it is greater than 1.2, shows that A phase disconnection faults have occurred, and otherwise that disconnection fault does not occur, terminates
Flow；
4. judging that the difference of A phase currents and C phase angle of phase current whether between [130 °, 180 °], then uses B phase voltages
Voltage magnitude smaller in A phases and C phases on Amplitude Ration, judges whether ratio is more than 1.2；If conditions above meets simultaneously, table
Bright B phases disconnection fault terminates flow otherwise that disconnection fault does not occur.
Embodiment 2
A kind of typical distribution net work structure schematic diagram as shown in Figure 2,10kV systems use the operation of isolated neutral
Mode and the radial network structure of single supply.There are n outlet (L1~Ln), every outlet to include several loads point on busbar
Branch.Using L1 as research object, branch's situation is as shown, wherein rectangle frame indicates that breaker, dot indicate block switch, arrow
Indicate load, remaining circuit L2~Ln is using simplified equivalent constructions.
Illustrated for single-phase wire break failure occurs on circuit L1 main feeders, it is assumed that disconnection fault point is located at the open circuit in figure
Between device A and block switch C, the changing rule of each phase current is as shown in figure 3, due to not exclusively matching for CT in figure before and after failure
It sets, without B phase current curves；
After A phases break, A phases and C phase currents reduce, and wherein failure A phase changes are most apparent, and amplitude of variation reaches
71.42%, meet the requirement of start-up criterion, reliably start breaking protection, C phase current magnitudes and A phase current magnitudes ratio be about at this time
It is 3.2, is more than 1.2.
The voltage at A represents the voltage of each measurement point between fault point and power supply at this time, and the voltage at C represents failure
The voltage of each measurement point between point and load, voltage change curve at A as shown in figure 4, at B voltage change curve as shown in figure 5,
The voltage magnitude highest of failure phase A phases at this time, about 7.5kV, two non-faulting phase voltage amplitudes are of substantially equal, about 5.5kV, and two
Person's ratio is about 1.38, is more than 1.2.
In summary as it can be seen that when A phase disconnection faults occur, faulted phase current obviously drops the changing rule of electric current, voltage
It is low, it can reliably start breaking protection；The ratio between non-faulting phase current and faulted phase current amplitude be more than 1.2, faulted phase voltage with
The ratio between non-faulting phase voltage amplitude also greater than 1.2 can reliably judge that A phase disconnection faults have occurred.For C phase disconnection faults,
Rule is similar, repeats no more.
When B phase disconnection faults occur, since B phases are fitted without CT, B phase currents can not be obtained.Two non-event at this time
Barrier phase current can also reduce, and since start-up criterion has higher sensitivity, can reliably start breaking protection.A phases at this time
It is almost the same with C phase current magnitudes, therefore the ratio between the two amplitude is not more than 1.2, the two phase difference will increase to 145 ° or so,
B phase voltages are significantly raised at this time, are about 1.4 with the ratio between A phases or C phase voltage amplitudes, are more than 1.2, therefore meet B phase disconnection faults
Criterion.As it can be seen that when B phases lack CT, by the changing rule of amount non-faulting phase current and three-phase voltage, can still judge
B phases break.
Embodiment 3
The structure connection signal of power distribution network single-phase disconnection breakdown judge system under CT as shown in FIG. 6 not exclusively configurations
Figure, the power distribution network single-phase disconnection breakdown judge system under CT not exclusively configurations are become by current/voltage conversion module, voltage/voltage
Change module, working power module, D/A converter module, data calculation processing module, control module, On-off signal output mould
Block, communication interface modules and human-computer interaction module composition, wherein D/A converter module respectively with current/voltage conversion module, electricity
Pressure/voltage change module is connected with data calculation processing module, control module respectively with data calculation processing module, human-computer interaction
Module, communication interface modules are connected with On-off signal output module；
Since CT is not exclusively configured, the current signal of input only has A phases and C phase currents, and the information of voltage of input is A, B, C
Three-phase voltage.Current signal is converted to by current/voltage conversion module, voltage signal through overvoltage/voltage transformation module suitable
The weak voltage signal of microsystem work and processing is closed, peak-to-peak value is ± 5V~± 15V；Concrete numerical value turns regarding used digital-to-analogue
It changes depending on chip；Above-mentioned weak voltage signal becomes discrete digital signal after D/A converter module is handled, then by data
Calculation processing module is calculated and is handled, and the calculating of the amplitude and phase of voltage, electric current is completed；Wherein data calculation processing mould
Block generally uses dsp chip, has TMS320 serial than more typical；
Control module carries out logical comparison and judgement to the result of calculation from data calculation processing module, judges current
Whether electrical magnitude relation meets criterion, and control module uses singlechip chip, such as STM32F singlechip chips.If satisfaction is sentenced
According to disconnection fault has occurred in circuit where showing, control On-off signal output module sends out trip signal, and control breaker is jumped
Lock；If being unsatisfactory for criterion, show that disconnection fault does not occur for protected circuit, broken wire protecting equipment is failure to actuate；
On-off signal output module is acted on by control module, can send out trip signal and alarm signal；Also it can receive
From external circuit breaker position status signal or other switching value information；
Working power module provides the direct-current working volts of different amplitudes, including 220V for entire protective device, ± 12V,
5V, 3.3V etc.；
Human-computer interaction module includes keyboard and liquid crystal display, for completing basic human-computer interaction function；
Communication interface modules is used for completing the information exchange function between broken wire protecting equipment and electric substation automation system,
Broken wire protecting equipment needs measurement, calculating and criterion result being uploaded to electric substation automation system, it is also desirable to receive from change
The various telecommands of power station automation system.
Claims (9)
1. the power distribution network single-phase disconnection fault judgment method under a kind of CT not exclusively configurations, it is characterised in that：Including fault initiating
Criterion and disconnection fault detection criteria；
Wherein fault initiating criterion is
In formula, Δ iφFor the variable quantity of A phases or C phase current sampling values, iφ(n) and iφ(n-N) it is A phases or C phase phase current times
And the current sampling data at 1 power frequency period former moment,For to continuous k | iφ| summation, 1<K≤N/2, INFor circuit
Rated current virtual value, ksetTo adjust threshold value coefficient, ksetNumerical value be 0.1~0.2；
Disconnection fault detection criteria includes B phase disconnection faults criterion, A phases or C phase disconnection fault criterions；
Wherein B phases disconnection fault criterion is
Wherein,Expression takes A phase currents and C phase current magnitude the greater；Expression takes A phases electric
Stream and C phase current magnitude smallers；Indicate the phase difference of A phase currents and C phase currents；Expression takes A
Phase voltage and C phase voltage amplitude smallers；
A phases or C phase disconnection fault criterions are
Wherein,Expression takes A phase currents and C phase current magnitude the greater；Expression takes A phases electric
Stream and C phase current magnitude smallers；Expression takes A phase voltages and C phase voltage amplitude the greater；Expression takes A phase voltages, B phase voltages and C phase voltage amplitude smallers.
2. the power distribution network single-phase disconnection fault judgment method under a kind of CT according to claim 1 not exclusively configurations, special
Sign is：Include the following steps：
1. broken wire protecting equipment constantly detects A phases and C phase currents in normal operation, when any phase current sampling amount of the two meets
When fault initiating criterion, breaking protection starts, and enters step 2.；
2. judging the size of A phases and C phase currents, the smaller value of higher value of the two is then used, judges whether ratio is more than 1.2,
It enters step 3., is otherwise entered step 4. if it is greater than 1.2；
3. if A phase currents are more than C phase currents, with voltage magnitude smaller in C phase voltages Amplitude Ration A phases and B phases, ratio is judged
Whether value is more than 1.2, if it is greater than 1.2, shows that C phase disconnection faults have occurred, and otherwise that disconnection fault does not occur, terminates stream
Journey；Equally, if C phase currents are more than A phase currents, with voltage magnitude smaller in A phase voltages Amplitude Ration B phases and C phases, judge
Whether ratio is more than 1.2, if it is greater than 1.2, shows that A phase disconnection faults have occurred, and otherwise that disconnection fault does not occur, terminates stream
Journey；
4. judging that the difference of A phase currents and C phase angle of phase current whether between [130 °, 180 °], then uses B phase voltage amplitudes
The smaller voltage magnitude than in upper A phases and C phases, judges whether ratio is more than 1.2；If conditions above meets simultaneously, show B phases
Disconnection fault terminates flow otherwise that disconnection fault does not occur.
3. the power distribution network single-phase disconnection fault judgment method under a kind of CT according to claim 1 not exclusively configurations, special
Sign is：ksetNumerical value be 0.15.
4. the power distribution network single-phase disconnection breakdown judge system under a kind of CT not exclusively configurations, which is characterized in that become by current/voltage
Mold changing block, voltage/voltage change module, working power module, D/A converter module, data calculation processing module, control module,
On-off signal output module, communication interface modules and human-computer interaction module composition, wherein D/A converter module respectively with electric current/
Voltage transformation module, voltage/voltage change module are connected with data calculation processing module, control module respectively at data calculating
Reason module, human-computer interaction module, communication interface modules are connected with On-off signal output module.
5. the power distribution network single-phase disconnection breakdown judge system under a kind of CT according to claim 4 not exclusively configurations, special
Sign is that the current signal of input only has A phases and C phase currents, and the information of voltage of input is A, B, C three-phase voltage.Current signal
By current/voltage conversion module, voltage signal suitable microsystem work and place are converted to through overvoltage/voltage transformation module
The weak voltage signal of reason, peak-to-peak value are ± 5V~± 15V；Above-mentioned weak voltage signal become after D/A converter module is handled from
Then scattered digital signal is calculated and is handled by data calculation processing module, voltage, the amplitude of electric current and phase are completed
It calculates；
Control module carries out logical comparison and judgement to the result of calculation from data calculation processing module, judges current electrical
Whether magnitude relation meets criterion.If meeting criterion, disconnection fault, control On-off signal output has occurred in circuit where showing
Module sends out trip signal, controls circuit breaker trip；If being unsatisfactory for criterion, show that disconnection fault does not occur for protected circuit,
Broken wire protecting equipment is failure to actuate；
On-off signal output module is acted on by control module, can send out trip signal and alarm signal；Also it can receive from outer
The circuit breaker position status signal in portion or other switching value information；
Working power module provides the direct-current working volts of different amplitudes for entire protective device；
Human-computer interaction module includes keyboard and liquid crystal display, for completing basic human-computer interaction function；
Communication interface modules is used for completing the information exchange function between broken wire protecting equipment and electric substation automation system, broken string
Protective device needs measurement, calculating and criterion result being uploaded to electric substation automation system, it is also desirable to receive and come from substation
The various telecommands of automated system.
6. the power distribution network single-phase disconnection breakdown judge system under a kind of CT according to claim 5 not exclusively configurations, special
Sign is that peak-to-peak value is ± 10V.
7. the power distribution network single-phase disconnection breakdown judge system under a kind of CT according to claim 5 not exclusively configurations, special
Sign is that data calculation processing module is the dsp chip of TMS320 series.
8. the power distribution network single-phase disconnection breakdown judge system under a kind of CT according to claim 5 not exclusively configurations, special
Sign is that control module is STM32F type singlechip chips.
9. the power distribution network single-phase disconnection breakdown judge system under a kind of CT according to claim 5 not exclusively configurations, special
Sign is that the direct-current working volts of different amplitudes are 220V, ± 12V, 5V and 3.3V.
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| CN111579927A (en) * | 2020-05-22 | 2020-08-25 | 南京南瑞继保电气有限公司 | Disconnection protection judgment method and device suitable for single-side power transmission line |
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| CN111007355A (en) * | 2019-12-11 | 2020-04-14 | 苏州银蕨电力科技有限公司 | Disconnection fault detection method based on wide-area synchronous intelligent sensor |
| CN111579927A (en) * | 2020-05-22 | 2020-08-25 | 南京南瑞继保电气有限公司 | Disconnection protection judgment method and device suitable for single-side power transmission line |
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| CN112345977B (en) * | 2020-10-21 | 2023-11-24 | 河南华润电力首阳山有限公司 | Electrical equipment and PT secondary circuit disconnection judging method, system and device thereof |
| CN113013880A (en) * | 2021-04-20 | 2021-06-22 | 西安兴汇电力科技有限公司 | Fault processing method based on 5G communication module distribution line |
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| CN114640093A (en) * | 2022-02-23 | 2022-06-17 | 北京天能继保电力科技有限公司 | Method and device for protecting broken line of distributed power transmission and distribution line |
| CN114938074A (en) * | 2022-03-22 | 2022-08-23 | 国网黑龙江省电力有限公司齐齐哈尔供电公司 | Automatic system applied to community power distribution |
| CN114938074B (en) * | 2022-03-22 | 2023-05-09 | 国网黑龙江省电力有限公司齐齐哈尔供电公司 | Automation system applied to district power distribution |
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