CN108666990A - A kind of power grid differential protecting method and system - Google Patents

A kind of power grid differential protecting method and system Download PDF

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Publication number
CN108666990A
CN108666990A CN201810581368.XA CN201810581368A CN108666990A CN 108666990 A CN108666990 A CN 108666990A CN 201810581368 A CN201810581368 A CN 201810581368A CN 108666990 A CN108666990 A CN 108666990A
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China
Prior art keywords
differential protection
head end
sample rate
current
rate current
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CN201810581368.XA
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CN108666990B (en
Inventor
刘长生
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Guangdong Keruide Electric Technology Co Ltd
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Guangdong Keruide Electric Technology Co Ltd
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02HEMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00Emergency 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
    • H02H7/26Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/261Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
    • H02H7/263Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of measured values

Abstract

The invention discloses a kind of power grid differential protecting method and systems.This method includes:The sampling instant of synchronous head end differential protection and end differential protection;Since sampling instant, the current amplitude and power direction of the administration section circuit of installation place are acquired with the first setting time interval respectively for head end differential protection and end differential protection;And collected current amplitude and power direction are sent to other side;The current amplitude and power direction that head end differential protection and end differential protection are sent according to itself collected current amplitude and power direction and opposite end respectively determine whether the administration section circuit breaks down.Power grid differential protecting method provided by the invention and system have the characteristics that realization method simplicity and breakdown judge accuracy are high.

Description

A kind of power grid differential protecting method and system
Technical field
The present invention relates to electric network protection fields, more particularly to a kind of power grid differential protecting method and system.
Background technology
With the continuous development of national power distribution network and the continuous promotion of distribution automation degree, to the reliability requirement of power supply Also higher and higher.The reliability of power supply is to weigh an important indicator of power supply and distribution quality, weighs the index of power supply and distribution reliability, The percentage of annual time is generally accounted for average of the whole year power-on time to indicate, for example, the annual time is 8760 hours, Yong Huquan Annual power off time 87.6 hours, i.e. power off time account for annual 1%, then power supply reliability is 99%.
The various intelligent monitorings of distribution automation, protective device are to improve the important leverage of power supply reliability, are especially matched Fault Isolation in power grid and power supply self-recovering function, and optical fiber differential protective technology and its device are pressed in electric system 10KV In system distribution, distribution network failure is quickly isolated, with the advantage that other intelligent apparatus are incomparable, and the country is first Qualified to exploit is walked, has started planning implementation in the subregion of south electric network at present.
The realization method of optical fiber differential protective:Line differential protection is often referred to the pilot protection of power transmission line, exactly uses optical fiber The protective device at power transmission line both ends is longitudinally tied by communication port, by the electrical quantity at each end the direction etc. of power (electric current) It is transmitted to opposite end, the electrical quantity at both ends is compared, with failure judgement in this line range or outside line range, to certainly It is fixed whether to cut off protected circuit.But in the prior art, the differential protection realization mechanism of transmission line of electricity is complicated, is passed to network The reliability requirement of transfer device is high.In addition, the synchronized sampling of data need to eliminate the communication delay of network communication, affects failure and sentence Disconnected accuracy.
Invention content
The object of the present invention is to provide a kind of power grid differential protecting method and systems, and there is realization method simplicity and failure to sentence The high feature of disconnected accuracy.
To achieve the above object, the present invention provides following schemes:
A kind of power grid differential protecting method, the method includes:
The sampling instant of synchronous head end differential protection and end differential protection, the head end differential protection The both ends of administration section circuit are respectively arranged in the end differential protection;
It is differential that head end differential protection acquires the head end since the sampling instant, with the first setting time interval The electric current of section circuit is administered in protective device installation place, is denoted as head end sample rate current, the head end sample rate current includes electric current Amplitude size and power direction;
The head end sample rate current is sent to the end differential protection by head end differential protection;
End differential protection acquires the end since the sampling instant, with first setting time interval The electric current of section circuit is administered in differential protection installation place, is denoted as end sample rate current, and the end sample rate current includes electricity The amplitude size and power direction of stream;
The end sample rate current is sent to the head end differential protection by end differential protection;
Head end differential protection determines the administrative area according to the head end sample rate current and the end sample rate current Whether section circuit breaks down;
End differential protection determines the administrative area according to the head end sample rate current and the end sample rate current Whether section circuit breaks down.
Optionally, the method further includes:
Every the second setting time interval synchronization once the head end differential protection and end differential protection Sampling instant.
Optionally, the sampling instant of synchronous the head end differential protection and end differential protection, specifically includes:
Head end differential protection terminad differential protection sends synchronic command;
After end differential protection receives the synchronic command, open PCA is interrupted;
Lock-out pulse is sent in the PCA interrupt pins of the end differential protection and produces by head end differential protection It is raw to interrupt, sampling instant is synchronized.
Optionally, the head end sample rate current is sent to the end differential protection in the head end differential protection Before device, further include:
Using window recursion Fu's formula algorithm, the real and imaginary parts of the head end sample rate current are calculated, and stamp sampled point volume Number;
The end differential protection by the end sample rate current be sent to the head end differential protection it Before, further include:
Using window recursion Fu's formula algorithm, the real and imaginary parts of the end sample rate current are calculated, and stamp sampled point volume Number.
Optionally, described that the administration section circuit is determined according to the head end sample rate current and the end sample rate current Whether break down, specifically includes:
Calculate the spill current between the head end sample rate current and the end sample rate current of synchronization;
Judge whether the spill current exceeds setting value;
If it is, the administration section line failure.
The present invention also provides a kind of power grid differential protective system, the system comprises:
Synchronization unit, the sampling instant for synchronizing head end differential protection and end differential protection, the head End differential protection and the end differential protection are respectively arranged in the both ends of administration section circuit;
Head end sampling unit, for head end differential protection since the sampling instant, between the first setting time Every the electric current for acquiring head end differential protection installation place administration section circuit, it is denoted as head end sample rate current, the head end Sample rate current includes the amplitude size and power direction of electric current;
It is differential to be sent to the end by head end transmission unit for head end differential protection for the head end sample rate current Protective device;
End sampling unit, for end differential protection since the sampling instant, when with first setting Between interval acquire the electric current of end differential protection installation place administration section circuit, be denoted as end sample rate current, it is described End sample rate current includes the amplitude size and power direction of electric current;
It is differential to be sent to the head end by end transmission unit for end differential protection for the end sample rate current Protective device;
Head end failure determination unit is adopted for head end differential protection according to the head end sample rate current and the end Sample electric current judges whether the administration section circuit breaks down;
End fault determination unit is adopted for end differential protection according to the head end sample rate current and the end Sample electric current judges whether the administration section circuit breaks down.
Optionally, the system also includes:
Sampling instant amending unit, for every the primary head end differential protection of the second setting time interval synchronization With the sampling instant of end differential protection.
Optionally, the synchronization unit specifically includes:
Transmission sub-unit is instructed, synchronic command is sent for head end differential protection terminad differential protection;
Open subelement is interrupted, after receiving the synchronic command for end differential protection, open PCA is interrupted;
Sampling instant synchronizes subelement, and lock-out pulse is sent to the differential guarantor in the end for head end differential protection Interruption is generated in the PCA interrupt pins of protection unit, and sampling instant is synchronized.
Optionally, the system also includes:
Head end sample rate current processing unit calculates the head end sample rate current for using window recursion Fu's formula algorithm Real and imaginary parts, and stamp sampling point number;
End sample rate current processing unit calculates the end sample rate current for using window recursion Fu's formula algorithm Real and imaginary parts, and stamp sampling point number.
Optionally, the head end failure determination unit, specifically includes:
Head end spill current computation subunit, the head end sample rate current for calculating synchronization and end sampling Spill current between electric current;
Head end spill current judgment sub-unit, for judging whether the spill current exceeds setting value;
Head end failure determination subelement, for when the spill current exceeds setting value, determining the administration section circuit It breaks down;
The end fault determination unit, specifically includes:
End spill current computation subunit, the head end sample rate current for calculating synchronization and end sampling Spill current between electric current;
End spill current judgment sub-unit, for judging whether the spill current exceeds setting value;
End fault determination subelement, for when the spill current exceeds setting value, determining the administration section circuit It breaks down.
According to specific embodiment provided by the invention, the invention discloses following technique effects:Power grid provided by the invention Differential protecting method and system synchronize the data sampling for administering the differential protection at the both ends of section circuit, and And the synchronism of the sampling instant of the differential protection at administration section circuit both ends is modified every setting duration, it is real Existing mechanism is simple.Terminal device synchronization can be effectively ensured by the way of synchronic command+lock-out pulse in the synchronization of data sampling Start sampling, greatly optimizes data synchronization mechanism.The amendment of data sampling is by the way of revision directive+corrected impulse It passes, the synchronism of terminal device data sampling during long-play can be effectively ensured.In addition, the calculating of sampled data Using window recursion Fu's formula algorithm, the amplitude size and power direction of synchronization both ends electric current, the transmission side of data are reflected Formula significantly reduces the transmission capacity of two end datas using the real and imaginary parts mode of transmission current value, reduces data biography Wrong probability is exported, the stability of data communication is improved with reliably, in turn, improves the accuracy of breakdown judge.
Description of the drawings
It in order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, below will be to institute in embodiment Attached drawing to be used is needed to be briefly described, it should be apparent that, the accompanying drawings in the following description is only some implementations of the present invention Example, for those of ordinary skill in the art, without having to pay creative labor, can also be according to these attached drawings Obtain other attached drawings.
Fig. 1 is power grid differential protecting method flow chart of the embodiment of the present invention;
Fig. 2 is the information transmission schematic diagram of head end of embodiment of the present invention differential protection and end differential protection;
Fig. 3 is that Interruption of the embodiment of the present invention samples schematic diagram;
Fig. 4 is sampling instant of embodiment of the present invention drift schematic diagram;
Fig. 5 is that schematic diagram is corrected in sampling instant of the embodiment of the present invention;
Fig. 6 is power grid differential protective system structural schematic diagram of the embodiment of the present invention.
Specific implementation mode
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 Site preparation describes, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other Embodiment shall fall within the protection scope of the present invention.
The object of the present invention is to provide a kind of power grid differential protecting method and systems, and there is realization method simplicity and failure to sentence The high feature of disconnected accuracy.
In order to make the foregoing objectives, features and advantages of the present invention clearer and more comprehensible, below in conjunction with the accompanying drawings and specific real Applying mode, the present invention is described in further detail.
Fig. 1 is power grid differential protecting method flow chart of the embodiment of the present invention, as shown in Figure 1, power grid provided by the invention is poor Dynamic guard method step is specific as follows:
Step 101:The sampling instant of synchronous head end differential protection and end differential protection, the head end are differential Protective device and the end differential protection are respectively arranged in the both ends of administration section circuit, and the administration section circuit is Refer to one section of circuit in transmission line of electricity, differential protection is mounted in the power distribution room at this section of circuit both ends;
Step 102:Head end differential protection is since the sampling instant, described in the acquisition of the first setting time interval The electric current of section circuit is administered in head end differential protection installation place, is denoted as head end sample rate current, the head end sample rate current packet Include the amplitude size and power direction of electric current;
Step 103:The head end sample rate current is sent to the end differential protection by head end differential protection;
Step 104:End differential protection is acquired since the sampling instant with first setting time interval The electric current of section circuit is administered in end differential protection installation place, is denoted as end sample rate current, the end sampling electricity Stream includes the amplitude size and power direction of electric current;
Step 105:The end sample rate current is sent to the head end differential protection by end differential protection;
Step 106:Head end differential protection determines institute according to the head end sample rate current and the end sample rate current State whether administration section circuit breaks down;
Step 107:End differential protection determines institute according to the head end sample rate current and the end sample rate current State whether administration section circuit breaks down.
The method further includes:
Every the second setting time interval synchronization once the head end differential protection and end differential protection Sampling instant.
The head end differential protection by the head end sample rate current be sent to the end differential protection it Before, further include:
Using window recursion Fu's formula algorithm, the real and imaginary parts of the head end sample rate current are calculated, and stamp sampled point volume Number;
The end differential protection by the end sample rate current be sent to the head end differential protection it Before, further include:
Using window recursion Fu's formula algorithm, the real and imaginary parts of the end sample rate current are calculated, and stamp sampled point volume Number.
Wherein, step 101 specifically includes:
Head end differential protection terminad differential protection sends synchronic command;
After end differential protection receives the synchronic command, open PCA is interrupted;
Lock-out pulse is sent in the PCA interrupt pins of the end differential protection and produces by head end differential protection It is raw to interrupt, sampling instant is synchronized.
It is described to determine whether the administration section circuit is sent out according to the head end sample rate current and the end sample rate current Raw failure, specifically includes:
Calculate the spill current between the head end sample rate current and the end sample rate current of synchronization;
Judge whether the spill current exceeds setting value;
If it is, the administration section line failure.
Three-phase current analog signal (the I that fundamental frequency is 50 hertza/Ib/Ic) mould carried out by multipath A/D converter The master controller of number conversion, head end differential protection (end differential protection) obtains analog-to-digital conversion number by spi bus According to being calculated, while master controller receives the three-phase current data from opposite end by 1X9 optical transceivers, and local sample is obtained The three-phase current data arrived and the three-phase current data from opposite end constitute split-phase type differential protection.Master controller passes through high-precision Temperature compensation type clock chip obtains real-time clock, and will be in the storage to the ferroelectric memory of SPI interface of the SOE events of generation.Master control The three-phase current data of the machine are sent to opposite end by device processed by 1X9 optical transceivers.The pulse sending port and hair of master controller Penetrate port phase and be connected to the transmitting terminals of 1X9 optical transceivers with after, the receiving terminal of master controller connect with interruptive port pin after again It is connect with the receiving terminal of 1X9 optical transceivers.
Head end differential protection is the promoter that data sampling synchronizes;End differential protection data sampling is same Step.Full-duplex communication, information transfer directions are as shown in Figure 2.
The transmitting terminal and receiving terminal of 1X9 optical transceivers are Transistor-Transistor Logic level, can directly be connected with the asynchronism transceiver of master controller It connects.
The information emission port of the master controller of head end differential protection is used for transmission data, when sending out data, arteries and veins It rushes sending port and is set as high level state;The pulse sending port of master controller sends pulse, is used for the synchronization of data sampling With data Sampling and Correcting, referred to hereinafter as lock-out pulse or corrected impulse.When sending lock-out pulse or corrected impulse, information transmitting terminal Mouth is in high level state.The transmission of pulse belongs to the permission of head end differential protection.
PCA interrupts the permission for belonging to end differential protection, and the triggering mode that PCA is interrupted is set as along triggering.End In the state of normally receiving data, PCA interruptions are shielded the receiving terminal of differential protection;Receive lock-out pulse when It waits, PCA interruptions are opened.The PCA interruptions of head end differential protection are constantly in masked state.
The process that data sampling synchronizes is divided into following components:
Data sampling synchronizes:Data sampling synchronizes the initial time of mainly synchronized data sampling, by head end differential protection Device is initiated, it is ensured that head end differential protection and end differential protection start sampling in synchronization.Synchronizing process:It is first Differential protection is held to send out synchronic command by information emission port first, notice end differential protection prepares synchronized sampling Moment;Open PCA is interrupted after end differential protection receives synchronic command, prepares to receive lock-out pulse.Then head end is differential Protective device sends out lock-out pulse by pulse sending port, and lock-out pulse is transferred to by optical fiber in end differential protection Interruption, the sampling of end differential protection OnNow analog quantity are generated on PCA pins.
Data sampling amendment:Data sampling amendment is after data synchronously complete, in following long-time sampling process In intert execute this operation.Purpose:Though due to the master controller crystal oscillator of head end differential protection and end differential protection Right frequency of oscillation is theoretically consistent, but during long-term operation, due to the difference of device, there will certainly be accumulated time Error, data sampling amendment are exactly to be designed to eliminate this error.Makeover process:Head end differential protection passes through letter first It ceases emission port and sends out revision directive, notice end differential protection prepares to correct sampling instant;End differential protection is received Open PCA is interrupted after to revision directive, prepares to receive corrected impulse.Then head end differential protection passes through pulse sending port Corrected impulse is sent out, corrected impulse is transferred on the PCA pins of end differential protection by optical fiber and generates interruption, and end is poor Dynamic protective device corrects the sampling instant of analog quantity immediately.
Data calculate:The data of the present invention program, which calculate, uses window recursion Fu's formula algorithm, calculates the real part of analog quantity And imaginary part.Head end differential protection and end differential protection a whole cycle before synchronization is using this moment are adopted Sampling point carries out Fu's formula calculating.
Data transmission:The transmission quantity of data is three analog quantity (Ia/Ib/Ic) real and imaginary parts, while stamping sampled point volume Number, convenient for the homogeneity of opposite end verification data, the dislocation of data is effectively prevent to transmit.
The step-out of data sampling resynchronizes:In the process of running in view of device, due to certain factor (such as strong electromagnetic Deng) cause the step-out of data sampling and design according to sampling step-out resynchronize.Synchronizing process is described above.
The correcting mode and process of data sampling:Data sampling using etc. time intervals start A/D conversion, to analog quantity into Row is discrete.It is illustrated by taking 24 point sampling of cycle as an example:
It is sampled using timer interrupt mode:The timing of one 24 points of cycle is 20ms/24=833.33us, i.e., Per 833.33us, timing enters 1 A/D conversion of interrupt start, is embodied in time shaft up-sampling moment square wave figure as shown in figure 3, figure T in 31=t2=... t24=833.33us.It is assumed that the master controller of head end differential protection and end differential protection and Crystal oscillator performance parameter is completely the same, then synchronized sampling initial time is passed through in both ends sampling, and the sampling instant figure at both ends may be implemented It fits like a glove on a timeline, but the master controller and crystal oscillator performance of head end differential protection and end differential protection are joined Number can not possibly be made to completely the same, the drift of sampling instant be will appear in actual moving process, as shown in figure 4, this drift If do not corrected, the square wave of the sampling instant square wave figure of head end differential protection and end differential protection will go out It is now gradually to misplace, followed by overlap first, moves in circles, the sampled data at both ends loses synchronization.
Data sampling modification method of the present invention:Data sampling instants figure using head end differential protection is standard, end The data sampling instants of differential protection are corrected, as shown in Figure 5.Makeover process is as follows:End differential protection receives To after Sampling and Correcting order, open PCA is interrupted;End differential protection receives Sampling and Correcting pulse and generates PCA interruptions, Time when changing the Sampling interrupt generation of subsequent point in interrupt service routine.1 cycle is corrected twice, and data can be effectively ensured It is synchronous.
Data of the power grid differential protecting method provided by the invention to the differential protection at the both ends of administration section circuit Sampling is synchronized, moreover, every setting sampling instant of the duration to the differential protection at administration section circuit both ends Synchronism is modified, and realization mechanism is simple.The synchronization of data sampling is by the way of synchronic command+lock-out pulse, Ke Yiyou Effect ensures the sampling of terminal device synchronous averaging, greatly optimizes data synchronization mechanism.The amendment of data sampling is referred to using amendment The mode of order+corrected impulse passes, and the synchronism of terminal device data sampling during long-play can be effectively ensured.This Outside, the calculating of sampled data uses window recursion Fu's formula algorithm, reflects the amplitude size and power of synchronization both ends electric current The transmission mode in direction, data significantly reduces the transmission of two end datas using the real and imaginary parts mode of transmission current value Capacity reduces the probability of data transmission error, improves the stability of data communication with reliably, in turn, improves failure and sentence Disconnected accuracy.
The present invention also provides a kind of power grid differential protective system, Fig. 6 is power grid differential protective system of the embodiment of the present invention Structural schematic diagram, as shown in 6 figures, the system comprises:
Synchronization unit 601, the sampling instant for synchronizing head end differential protection and end differential protection are described Head end differential protection and the end differential protection are respectively arranged in the both ends of administration section circuit, the administrative area Section circuit refers to one section of circuit in transmission line of electricity, and differential protection is mounted in the power distribution room at this section of circuit both ends;
Head end sampling unit 602, for head end differential protection since the sampling instant, with the first setting time Interval acquires the electric current of head end differential protection installation place administration section circuit, is denoted as head end sample rate current, the head End sample rate current includes the amplitude size and power direction of electric current;
The head end sample rate current is sent to the end by head end transmission unit 603 for head end differential protection Differential protection;
End sampling unit 604 is set for end differential protection since the sampling instant with described first Time interval acquires the electric current of end differential protection installation place administration section circuit, is denoted as end sample rate current, institute State the amplitude size and power direction that end sample rate current includes electric current;
The end sample rate current is sent to the head end by end transmission unit 605 for end differential protection Differential protection;
Head end failure determination unit 606, for head end differential protection according to the head end sample rate current and the end End sample rate current judges whether the administration section circuit breaks down;
End fault determination unit 607, for end differential protection according to the head end sample rate current and the end End sample rate current judges whether the administration section circuit breaks down.
The system also includes:
Sampling instant amending unit, for every the primary head end differential protection of the second setting time interval synchronization With the sampling instant of end differential protection.
Head end sample rate current processing unit calculates the head end sample rate current for using window recursion Fu's formula algorithm Real and imaginary parts, and stamp sampling point number;
End sample rate current processing unit calculates the end sample rate current for using window recursion Fu's formula algorithm Real and imaginary parts, and stamp sampling point number.
Wherein, synchronization unit specifically includes:
Transmission sub-unit is instructed, synchronic command is sent for head end differential protection terminad differential protection;
Open subelement is interrupted, after receiving the synchronic command for end differential protection, open PCA is interrupted;
Sampling instant synchronizes subelement, and lock-out pulse is sent to the differential guarantor in the end for head end differential protection Interruption is generated in the PCA interrupt pins of protection unit, and sampling instant is synchronized.
The head end failure determination unit, specifically includes:
Head end spill current computation subunit, the head end sample rate current for calculating synchronization and end sampling Spill current between electric current;
Head end spill current judgment sub-unit, for judging whether the spill current exceeds setting value;
Head end failure determination subelement, for when the spill current exceeds setting value, determining the administration section circuit It breaks down;
The end fault determination unit, specifically includes:
End spill current computation subunit, the head end sample rate current for calculating synchronization and end sampling Spill current between electric current;
End spill current judgment sub-unit, for judging whether the spill current exceeds setting value;
End fault determination subelement, for when the spill current exceeds setting value, determining the administration section circuit It breaks down.
Data of the power grid differential protective system provided by the invention to the differential protection at the both ends of administration section circuit Sampling is synchronized, moreover, every setting sampling instant of the duration to the differential protection at administration section circuit both ends Synchronism is modified, and realization mechanism is simple.The synchronization of data sampling is by the way of synchronic command+lock-out pulse, Ke Yiyou Effect ensures the sampling of terminal device synchronous averaging, greatly optimizes data synchronization mechanism.The amendment of data sampling is referred to using amendment The mode of order+corrected impulse passes, and the synchronism of terminal device data sampling during long-play can be effectively ensured.This Outside, the calculating of sampled data uses window recursion Fu's formula algorithm, reflects the amplitude size and power of synchronization both ends electric current The transmission mode in direction, data significantly reduces the transmission of two end datas using the real and imaginary parts mode of transmission current value Capacity reduces the probability of data transmission error, improves the stability of data communication with reliably, in turn, improves failure and sentence Disconnected accuracy.
Each embodiment is described by the way of progressive in this specification, the highlights of each of the examples are with other The difference of embodiment, just to refer each other for identical similar portion between each embodiment.For system disclosed in embodiment For, since it is corresponded to the methods disclosed in the examples, so description is fairly simple, related place is said referring to method part It is bright.
Principle and implementation of the present invention are described for specific case used herein, and above example is said The bright method and its core concept for being merely used to help understand the present invention;Meanwhile for those of ordinary skill in the art, foundation The thought of the present invention, there will be changes in the specific implementation manner and application range.In conclusion the content of the present specification is not It is interpreted as limitation of the present invention.

Claims (10)

1. a kind of power grid differential protecting method, which is characterized in that the method includes:
The sampling instant of synchronous head end differential protection and end differential protection, the head end differential protection and institute State the both ends that end differential protection is respectively arranged in administration section circuit;
Head end differential protection acquires the head end differential protection since the sampling instant, with the first setting time interval The electric current of section circuit is administered in device installation place, is denoted as head end sample rate current, the head end sample rate current includes the amplitude of electric current Size and power direction;
The head end sample rate current is sent to the end differential protection by head end differential protection;
It is differential that end differential protection acquires the end since the sampling instant, with first setting time interval The electric current of section circuit is administered in protective device installation place, is denoted as end sample rate current, the end sample rate current includes electric current Amplitude size and power direction;
The end sample rate current is sent to the head end differential protection by end differential protection;
Head end differential protection determines the administration section line according to the head end sample rate current and the end sample rate current Whether break down on road;
End differential protection determines the administration section line according to the head end sample rate current and the end sample rate current Whether break down on road.
2. power grid differential protecting method according to claim 1, which is characterized in that the method further includes:
Every the sampling of the second setting time interval synchronization once the head end differential protection and end differential protection Moment.
3. power grid differential protecting method according to claim 1, which is characterized in that the synchronous head end differential protection With the sampling instant of end differential protection, specifically include:
Head end differential protection terminad differential protection sends synchronic command;
After end differential protection receives the synchronic command, open PCA is interrupted;
Lock-out pulse is sent in the PCA interrupt pins of the end differential protection in generation by head end differential protection It is disconnected, sampling instant is synchronized.
4. according to the method described in claim 1, it is characterized in that, the head end is sampled in the head end differential protection Electric current is sent to before the end differential protection, further includes:
Using window recursion Fu's formula algorithm, the real and imaginary parts of the head end sample rate current are calculated, and stamp sampling point number;
Before the end sample rate current is sent to the head end differential protection by the end differential protection, also Including:
Using window recursion Fu's formula algorithm, the real and imaginary parts of the end sample rate current are calculated, and stamp sampling point number.
5. according to the method described in claim 1, it is characterized in that, described adopt according to the head end sample rate current and the end Sample electric current determines whether the administration section circuit breaks down, and specifically includes:
Calculate the spill current between the head end sample rate current and the end sample rate current of synchronization;
Judge whether the spill current exceeds setting value;
If it is, the administration section line failure.
6. a kind of power grid differential protective system, which is characterized in that the system comprises:
Synchronization unit, the sampling instant for synchronizing head end differential protection and end differential protection, the head end are poor Dynamic protective device and the end differential protection are respectively arranged in the both ends of administration section circuit;
Head end sampling unit is adopted for head end differential protection since the sampling instant with the first setting time interval The electric current for collecting head end differential protection installation place administration section circuit is denoted as head end sample rate current, the head end sampling Electric current includes the amplitude size and power direction of electric current;
The head end sample rate current is sent to the end differential protection by head end transmission unit for head end differential protection Device;
End sampling unit, for end differential protection since the sampling instant, between first setting time Every the electric current for acquiring end differential protection installation place administration section circuit, it is denoted as end sample rate current, the end Sample rate current includes the amplitude size and power direction of electric current;
The end sample rate current is sent to the head end differential protection by end transmission unit for end differential protection Device;
Head end failure determination unit samples electricity for head end differential protection according to the head end sample rate current and the end Stream judges whether the administration section circuit breaks down;
End fault determination unit samples electricity for end differential protection according to the head end sample rate current and the end Stream judges whether the administration section circuit breaks down.
7. power grid differential protective system according to claim 6, which is characterized in that the system also includes:
Sampling instant amending unit, for every the second setting time interval synchronization once the head end differential protection and end Hold the sampling instant of differential protection.
8. power grid differential protective system according to claim 6, which is characterized in that the synchronization unit specifically includes:
Transmission sub-unit is instructed, synchronic command is sent for head end differential protection terminad differential protection;
Open subelement is interrupted, after receiving the synchronic command for end differential protection, open PCA is interrupted;
Sampling instant synchronizes subelement, and lock-out pulse, which is sent to the end differential protection, for head end differential protection fills Interruption is generated in the PCA interrupt pins set, and sampling instant is synchronized.
9. system according to claim 6, which is characterized in that the system also includes:
Head end sample rate current processing unit calculates the real part of the head end sample rate current for using window recursion Fu's formula algorithm And imaginary part, and stamp sampling point number;
End sample rate current processing unit calculates the real part of the end sample rate current for using window recursion Fu's formula algorithm And imaginary part, and stamp sampling point number.
10. system according to claim 6, which is characterized in that the head end failure determination unit specifically includes:
Head end spill current computation subunit, the head end sample rate current for calculating synchronization and the end sample rate current Between spill current;
Head end spill current judgment sub-unit, for judging whether the spill current exceeds setting value;
Head end failure determination subelement, for when the spill current exceeds setting value, determining that the administration section circuit occurs Failure;
The end fault determination unit, specifically includes:
End spill current computation subunit, the head end sample rate current for calculating synchronization and the end sample rate current Between spill current;
End spill current judgment sub-unit, for judging whether the spill current exceeds setting value;
End fault determination subelement, for when the spill current exceeds setting value, determining that the administration section circuit occurs Failure.
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