CN108832606B - It is a kind of meter and region measurement capability active distribution network protection scheme - Google Patents
It is a kind of meter and region measurement capability active distribution network protection scheme Download PDFInfo
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- CN108832606B CN108832606B CN201810644271.9A CN201810644271A CN108832606B CN 108832606 B CN108832606 B CN 108832606B CN 201810644271 A CN201810644271 A CN 201810644271A CN 108832606 B CN108832606 B CN 108832606B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/28—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for meshed systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0092—Details of emergency protective circuit arrangements concerning the data processing means, e.g. expert systems, neural networks
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
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Abstract
The invention discloses a kind of meter and the active distribution network protection schemes of region measurement capability, include the following steps: that (1) establishes inverse distributed power Faults Characteristic Analysis model under power limitation control mode;(2) fault characteristic of distributed generation resource and its influence to power distribution network current protection under fault condition are analyzed;(3) it builds active distribution network protection system architecture and the positioning of faulty line is completed according to fault current direction at breaker;(4) the grid-connected active distribution network reclosing scheme with distribution protection actuation time time cooperation of distributed generation resource is utilized;The invention can eliminate DG and access the influence generated to distribution protection, while using current failure component as feature electrical quantity, eliminate influence of the load current for protection scheme, reliability with higher.Mentioned reclosing scheme does not change the original relaying configuration of power distribution network, and not against communication network, has very strong economic advantages and engineering practicability.
Description
Fields
The invention belongs to distribution protection technical fields, and in particular to it is a kind of meter and region measurement capability active distribution network
Protection scheme.
Background technique
The concept of distributed generation resource results from the 1980s, referring to the appearance introduced in a power distribution system close to user side
Measure little power supply.Increasingly mature with the small power generations technology such as solar energy, wind energy, more and more schemes are to utilize dispersion
Resource meet the needs of small user.
The distributed generation resource in China develops overall state and keeps up with, but by resources supplIes, policy criteria and technology
The limitation of type difference etc., the fields such as photovoltaic power generation, cogeneration of heat and power development still in initial stage, scale is smaller.Although
Wind-power electricity generation increases by 50 times in the installed capacity of past 7 years, but since China's Wind Power Generation Industry development speed is too fast, professional standard and electricity
Network planning draws and relatively lags behind, and blower does not have the technical capabilities such as low voltage crossing, causes blower that cannot normally generate electricity by way of merging two or more grid systems.Although
Many Demonstration Bases based on solar energy power generating have also been built on the ground such as west area such as Yinchuan of Ningxia Province, but electricity consumption city, China
Field distribution can not fit like a glove with solar energy distribution.As the biggish eastern region of electricity consumption, land price is more high
It is expensive, if the large-scale ground power station of construction centralization, will undoubtedly greatly improve cost, it is unfavorable for pushing away on a large scale for solar power generation
Extensively;And contain West Region Development centralization abundant power station in solar energy, and will appear the loss problem of electric power long-distance transport.
Therefore, the following country is while further carrying out development of small scale hydropower station, it will emphasis promotes photovoltaic power generation and cogeneration of heat and power equal part
The development of cloth power technology.
The protection of conventional electrical distribution net is the radiation characteristic according to power distribution network, it then follows principle of selectivity passes through matching for protection equipment
The isolation for realizing fault zone is closed, to reach the smallest power loss range, guarantees power supply reliability.And after distributed generation resource access,
The unidirectional characteristics of tidal flow of power distribution network becomes bi-directional current characteristic, and the premise of traditional protection setting value order has been not present, and traditional three
Segmentation current protection is no longer valid.Meanwhile distribution net work structure is complicated, branch is more, and the measurement capability of part distribution web area
Limited, the engineering practicability of current existing protection scheme is not strong.In conjunction with practical development and instantly how demand, solve distributed electrical
It is urgent problem that source access bring, which influences and cope with the complex conditions of power distribution network,.
Summary of the invention
The present invention exactly be directed to the problems of the prior art, provide it is a kind of meter and region measurement capability active distribution network
Protection scheme can satisfy distributed generation resource access, for the distribution web area of measurement capability scarcity, can not change original
Distribution protection configuration, also not by any communication mode, feasibility and economy of the implementation on engineering construction.
To achieve the goals above, the technical solution adopted by the present invention is that: it is a kind of meter and distributed generation resource it is grid-connected be overlapped
The active distribution network protection scheme of lock time cooperation, includes the following steps:
S1 establishes inverse distributed power Faults Characteristic Analysis model under power limitation control mode, inverse after model simplification
Become device DC voltage to keep constant;
S2 analyzes the fault characteristic of distributed generation resource and its influence to power distribution network current protection under fault condition, described
The current failure characteristic of inverse distributed power depends on the control strategy of inverter;
S3, for the excellent region of power distribution network measurement capability, the structure type combined using centralization and layer-stepping is taken
Active distribution network protection system architecture is built, current direction in the protective device of front and back occurs by comparing failure, completes faulty line
Positioning;
S4, for the region of power distribution network measurement capability scarcity, when being acted using distributed generation resource is grid-connected with distribution protection
Between time cooperation active distribution network reclosing scheme.
As an improvement of the present invention, the step 2 further comprises:
S21 carries out Faults Characteristic Analysis, inverter output power to inverse distributed power under power limitation control mode
Formula under dq coordinate system are as follows:
Wherein, P, Q are the active power and reactive power of IIDG output;ugd、ugqFor d, q axis component of network voltage;id、
iqFor d, q axis component of inverter output current;
When d axis is oriented to network voltage vector, have:
Wherein, ugFor network voltage vector magnitude;
By above-mentioned two formulas simultaneous solution, inverter PQ control reference current is obtained are as follows:
Wherein, Pref、QrefFor the active power reference value and reactive power reference qref of IIDG;id.ref、iq.refNormally to transport
Watt current reference value and reactive current reference value when row;
Idle reference current iq.ref.fIt is determined by the low voltage crossing characteristic taken;In view of the inverter of distributed generation resource
Power component conveyance capacity is limited, if maximum output current imaxFor rated current inα (1.2≤α≤1.5) times, i.e. imax=α
in, then have:
Wherein, id.ref.f、iq.ref.fWatt current reference value and reactive current reference value when for failure;
S22, analyze fault condition under influence of the distributed generation resource to power distribution network current protection: the distributed generation resource for
Protective device downstream helps increasing effect, and current value increases at protective device;The distributed generation resource is to the guarantor swum thereon
Protection unit, the current value that the system of will cause flows through protective device reduce.
As an improvement of the present invention, active distribution network protection system architecture is from top to bottom successively wrapped in the step S3
Containing central processing unit, region decision package and local three levels of protection location,
A local protection location is equipped at each breaker, for receiving higher level region decision package for disconnected
The action command that road device is assigned, and then divide-shut brake control is carried out to breaker;
The region decision package is set in power distribution network subregion, setting one in each subregion, for receiving each open circuit
The current failure component direction that local protection location provides at device judges information, locks fault section by matrix operation, and will
Trip signal is issued to corresponding local protection location, controls corresponding circuit breaker trip by local protection location, completes failure
The positioning and excision of section;
It is equipped with a central processing unit in the power distribution network and carries out overall scheduling controlling.
As another improvement of the invention, current failure component direction uses " direction+amplitude " in the step S3
Dual method of discrimination,
" direction " method of discrimination are as follows: if current direction is constant after failure and amplitude increases, current failure component side
To identical as PRE-FAULT CURRENT direction;If current direction changes after failure or current direction is constant and amplitude reduces, electric current
Fault component direction is contrary with PRE-FAULT CURRENT;
" amplitude " method of discrimination are as follows: when failure is located within the section of protection zone, section both ends current and phase difference is 0 °;
When failure be located at protection zone section except or when no fault occurs, section both ends current and phase difference be 180 °.
As another of the invention improvement, in the step S3 faulty line positioning the following steps are included:
S31 carries out multidomain treat-ment by bound pair power distribution network of open type interconnection switch, 1 is numbered to bus in region~
N is installed with 2 breakers between bus i and bus j;
S32 is established according to the bus quantity n in Local Area Network topology and is stored n × n rank null matrix;
S33, according to current failure component direction criterion, if current failure component direction and electricity before failure at breaker i-j
It is identical to flow direction, then Aij=1 (i ≠ j);If at breaker j-i current failure component direction it is contrary with PRE-FAULT CURRENT or
Fault current is not detected at person's breaker j-i, then Aij=0 (i ≠ j).And then obtain fault judgment matrix DF, matrix element
It is plain as follows:
S34, by AijWith AjiLogic XOR operation is executed, ifIt then can be determined that between bus i and bus j
Route is normal;IfIt then can be determined that fault point between bus i and bus j.
As a further improvement of the present invention, the step S4 further comprises:
S41, fault detection: real-time detection DG and power distribution network point of common coupling, voltage, once it detects due to Distribution Network Failure
Lead to the reduction of PCC voltage, disconnects the connection of DG and power distribution network immediately.
S42, distribution network protection action logic: if failure occurs in feeder line, the excision of the non-selectivity feeder line is delayed by Td
It is overlapped the feeder line.
S43, DG grid-connected action logic again: judging fault zone, if detecting, failure occurs in PCC breaker upstream,
After Tm is delayed and waits power distribution network reclosing, the voltage of PCC is detected, prepares simultaneous interconnecting and shows to match if meeting same period condition
Electric network fault is transient fault, and failure has been eliminated;Or distribution network failure is permanent fault, but DG is located at distribution network failure
Upstream;No matter which kind of situation, DG carries out simultaneous interconnecting operation;If being unsatisfactory for grid-connected conditions always, show distribution network failure
For permanent fault, and DG is located at distribution network failure downstream, and DG continues to keep off-network state.
Compared with prior art, the invention proposes it is a kind of meter and region measurement capability active distribution network protection scheme,
It has the beneficial effect that
(1) present invention is realized by the position of interconnection switch and breaker in distribution network topology to power distribution network
Multidomain treat-ment, reduce the network matrix order of centerized fusion, accelerate the arithmetic speed of algorithm, improve protective device
Execution efficiency;
(2) present invention is without adjusting circuit breaker current action value, evaded distributed generation resource Injection Current for
The influence of protection technique reduces a possibility that distributed generation resource accesses lower distribution protection error action of device, tripping, improves and match
Safety and reliability under the conditions of electric network fault;
(3) present invention is realized using the grid-connected time cooperation with reclosing of distributed generation resource for measurement capability scarcity
The relay protection of distribution web area, the program do not change original distribution protection configuration, also do not need by any communication party
Formula, it is only necessary to work good power distribution network reclosing and DG grid-connected time, engineering construction has feasibility and economy.
Detailed description of the invention
Fig. 1 is method flow schematic diagram of the invention;
Fig. 2 is the grid-connected equivalent schematic of inverse distributed power of the invention;
Fig. 3 is protection system hierarchy schematic diagram of the invention;
Fig. 4 is pilot protection active region schematic diagram of the invention;
Fig. 5 is the protection act logical schematic of active distribution network of the invention;
Fig. 6 is the operation of DG off-network and three-step charging time coordination relation schematic diagram of the invention.
Specific embodiment
Below with reference to drawings and examples, the present invention is described in detail.
Embodiment 1
It is a kind of meter and region measurement capability active distribution network protection scheme, as shown in Figure 1, including the following steps:
S1 establishes inverse distributed power Faults Characteristic Analysis model under power limitation control mode, inverse distributed
Power grid equivalent schematic is as shown in Figure 2.Due to inverter direct-flow side parallel connection energy storage device and illumination and wind speed etc. pair
The factor that distributed generation resource is affected during fault transient it is believed that remain unchanged, can be by DC side voltage of converter UdcIt sees
It keeps constant.Therefore the current failure characteristic of inverse distributed power depends primarily on the control strategy of inverter.
S2 analyzes the fault characteristic of distributed generation resource and its influence to power distribution network current protection, step under fault condition
S2 further comprises:
S21 carries out Faults Characteristic Analysis, inverter output power to inverse distributed power under power limitation control mode
Formula under dq coordinate system are as follows:
Wherein, P, Q are the active power and reactive power of IIDG output;ugd、ugqFor d, q axis component of network voltage;id、
iqFor d, q axis component of inverter output current;
When d axis is oriented to network voltage vector, have:
Wherein, ugFor network voltage vector magnitude;
By above-mentioned two formulas simultaneous solution, inverter PQ control reference current is obtained are as follows:
Wherein, Pref、QrefFor the active power reference value and reactive power reference qref of IIDG;id.ref、iq.refIt is normal
Watt current reference value and reactive current reference value when operation;
When power distribution network breaks down, grid voltage sags occur at points of common connection, inverse distributed power needs mention
For reactive current to guarantee grid stability.Idle reference current iq.ref.fIt is determined by the low voltage crossing characteristic taken.It is idle
Reference current iq.ref.fIt is determined by the low voltage crossing characteristic taken.In view of the inverter power element overcurrent of distributed generation resource
Ability is limited, if maximum output current imaxFor rated current inα (1.2≤α≤1.5) times, i.e. imax=α in, then have:
Wherein, id.ref.f、iq.ref.fWatt current reference value and reactive current reference value when for failure;
In conclusion PQ type IIDG can be equivalent to and network voltage U at PCCPCCRelated voltage-controlled current source.General feelings
Under condition, the short circuit current that IIDG is provided when failure occurs can be greater than the maximum current that its conveyance capacity allows, inverter outlet
Amplitude limit link controls inverter output current for imax。
S22, analyze influence of the distributed generation resource to power distribution network current protection under fault condition: distributed generation resource accesses distribution
After net, when short trouble occurs, for the protective device in distributed generation resource downstream, system and inverse distributed power are simultaneously
Short circuit current is injected to fault point, helps increasing to act on due to distributed generation resource, current value increases at protective device, has malfunction can
Can, and distributed generation resource capacity is bigger, protective device malfunction possibility is higher;Meanwhile the protection for distributed generation resource upstream
Device, the short circuit current that distributed generation resource provides can raise grid entry point voltage, and the current value for causing system to flow through protective device subtracts
Small, it is possible to have tripping for sensitivity decrease, and distributed generation resource capacity is bigger, and protective device tripping possibility is higher.
S3, for the excellent region of power distribution network measurement capability, the structure type combined using centralization and layer-stepping, such as
Shown in Fig. 3, active distribution network protection system architecture is built, the active distribution network protection system architecture from top to bottom successively includes
Central processing unit (Central Processing Unit, CPU), region decision package (Region Decision Unit,
RDU) and local protection location (Local Protection Unit, LPU) three levels,
A LPU, function are installed at each breaker are as follows: acquisition three-phase voltage, three-phase current and switch state;
The action command that higher level RDU assigns breaker is received, and then divide-shut brake control is carried out to breaker;
Multidomain treat-ment is carried out by bound pair power distribution network of open type interconnection switch, a RDU, effect are set in each region
It is to receive the current failure component direction that LPU is provided at each breaker to judge information, fault section is locked by matrix operation, and
Trip signal is issued to corresponding LPU, corresponding circuit breaker trip is controlled by LPU, completes the positioning and excision of fault section;
It is equipped with a CPU in power distribution network and carries out overall scheduling controlling.CPU is by receiving the electricity that LPU is uploaded at interconnection switch
Stream information judges power distribution network topological structure.If electric current is not 0 at interconnection switch, illustrate that interconnection switch is closed, power distribution network
Topological structure changes.
It is assumed that Same Name of Ends is respectively positioned on close to adjacent bus side when all mutual inductors are installed in power distribution network.Theoretically, when event
When barrier is located within protection section, section both ends current and phase difference is 0 °;When failure be located at protection zone section except or fault-free hair
When raw, section both ends current and phase difference is 180 °.In view of there are errors and power transmission line there is distribution for electric current, voltage transformer
Capacitor etc. influences, and when except failure being located at protection zone section, two sides current and phase difference is approximately only 180 °, and when failure is located at
When protecting within section, section two sides current phase is also approximately only 0 °, therefore the operating space protected is general such as Fig. 4 institute
Show.
Due to the method for operation that distribution line generally uses single supply radioactivity to power, even if being connected to DG on route, DG is mentioned
The short circuit current of confession is also smaller, and short dot downstream protective device is insufficient to allow reliably to start.Therefore, Unit protection is transported
There are problems that weak feedback for power distribution network.For this purpose, the dual method of discrimination in " direction+amplitude " is used to current failure component direction,
Complete the positioning of fault section.
Criterion of this programme for current failure component direction are as follows: if current direction is constant after failure and amplitude increases,
Cutoff current fault component direction is identical as PRE-FAULT CURRENT direction;If current direction changes after failure or current direction is constant
And amplitude reduces, then Cutoff current fault component direction is contrary with PRE-FAULT CURRENT.
Wherein faulty line positioning the following steps are included:
S31 carries out multidomain treat-ment by bound pair power distribution network of open type interconnection switch, 1 is numbered to bus in region~
N is installed with 2 breakers between bus i and bus j, then the breaker that will be close to bus i is named as breaker i-j;Together
Reason, the breaker that will be close to bus j are named as breaker j-i;
S32 is established according to the bus quantity n in Local Area Network topology and is stored n × n rank null matrix;
S33, according to current failure component direction criterion, if current failure component direction and electricity before failure at breaker i-j
It is identical to flow direction, then Aij=1 (i ≠ j);If at breaker j-i current failure component direction it is contrary with PRE-FAULT CURRENT or
Fault current is not detected at person's breaker j-i, then Aij=0 (i ≠ j).And then obtain fault judgment matrix DF, matrix element
It is plain as follows:
S34, by AijWith AjiLogic XOR operation is executed, ifIt then can be determined that between bus i and bus j
Route is normal;IfIt then can be determined that fault point between bus i and bus j.LPU sends out respective circuit breakers
Action signal is sent, the excision of faulty line is completed.
Power distribution network topological structure is variable: for economy, the reasonability for meeting electric energy distribution, the connection meeting of distribution line
Change frequent occurrence, while the throwing of DG is moved back and determined by DG operator, there is randomness and uncontrollability, lead to active distribution network
Topologies change frequency is very high.This just needs protection scheme to have certain topology adaptation function.It is opened up for reply power distribution network
The change of structure is flutterred, the method that this programme is taken is the electric current that interconnection switch is flowed through by the LPU detection for being mounted on interconnection switch
(under normal condition, at interconnection switch 0) current value is to information.When detecting at interconnection switch there are when electric current, by interconnection switch
Information is uploaded to associated two RDU by the LPU at place, is completed the merging of zone circuit breaker by two RDU and is renumberd,
And then new fault judgment matrix is generated, complete the fault section location under malfunction.
The reply weak feedback phenomenon of distributed generation resource: the method for operation that distribution line generally uses single supply radioactivity to power, i.e.,
Just distributed generation resource is connected on route, the short circuit current that distributed generation resource provides is also smaller, is insufficient to allow short dot downstream
Protective device reliably starts.Therefore, there is weak feedback in the distribution protection containing distributed generation resource.The solution of this programme
It is: when RDU confirms that certain section of route side LPU detects fault current and opposite end LPU is small without uploading failure because of short circuit current
When information (i.e. breaker does not detect fault current), judge that short dot is located on this section of protected circuit, this section of line of tripping
Road both ends breaker.
Cope with distribution feeder multiple-limb situation: compared with transmission line of electricity, the structure of distribution line is increasingly complex, feeder line
Often there is the case where multiple-limb.Therefore, when load in branch carries out switching, the change of load current will affect biography
The reliability of electric grid relay protection scheme under unified central planning.In this regard, using failure of the current component as distribution network failure feature electrical quantity.
Branch's load current does not appear in fault network, therefore reduces distribution feeder multiple-limb situation for protection scheme
It influences.
Reply power distribution network underloading electric current is not easy to detect: when load current is smaller at light load for distribution line, often having and is difficult to
The feature of detection.The amplitude of electric current and direction on distribution feeder are unable to judge accurately before failure occurs.The solution party of this programme
Method is: when distribution line underloading, when load current can not detect, not being defined to current amplitude and direction.When failure occurs
When, current amplitude increases, and fault current direction is the direction of current failure component.
S4 is proposed for the region of power distribution network measurement capability scarcity using distributed generation resource is grid-connected and distribution protection
The active distribution network reclosing scheme of actuation time time cooperation, protocol procedures are as shown in figure 5, the specific implementation steps are as follows institute
It states:
S41, fault detection: real-time detection DG and power distribution network point of common coupling (Point of Common Coupling,
PCC) voltage disconnects the connection of DG and power distribution network once detecting since Distribution Network Failure leads to the reduction of PCC voltage immediately.At this point,
No longer contain DG in distribution, becomes single supply radial networks.
S42, distribution network protection action logic: if failure occurs in feeder line, the excision of the non-selectivity feeder line is delayed by Td
It is overlapped the feeder line.At this point, the problem of not including DG in power distribution network, non-Switching Synchronization be not present.Meanwhile it the on-position of DG and connecing
Power distribution network will not be had an impact by entering capacity, and three-step charging scheme can more accurately judge fault zone, be had
The movement of selectivity is in tripping or signal.
S43, DG grid-connected action logic again: judging fault zone, if detecting, failure occurs in PCC breaker upstream,
After Tm is delayed and waits power distribution network reclosing, the voltage of PCC is detected, prepares simultaneous interconnecting and shows to match if meeting same period condition
Electric network fault is transient fault, and failure has been eliminated;Or distribution network failure is permanent fault, but DG is located at distribution network failure
Upstream;No matter which kind of situation, DG carries out simultaneous interconnecting operation;If being unsatisfactory for grid-connected conditions always, show distribution network failure
For permanent fault, and DG is located at distribution network failure downstream, and DG continues to keep off-network state.
It is assumed that DG turn-off time is T1, including PCC under-voltage protection actuation time T1A and PCC point switch off-time
T1B;The value of T1A is depending on protection algorism, at least 10ms;The value of T1B is adjusted by PCC solid-state switch movement speed,
Representative value is 10ms.It is assumed that distribution protection actuation time is T2, representative value is 10-25ms in engineering.By PCC protection and distribution
The logic analysis of net protection act is it is found that should have T1 < T2, as shown in Figure 6.
If not configuring former acceleration reclosure brake, even if being not meant to that three-stage electric current is protected in the case where meeting T1 < T2
Shield being capable of action message.The data that three-step charging obtains within the preceding T1 time include the short circuit current of DG injection, from
And cause the fault message obtained within the T1 time inaccurate, do not have availability.It in order to overcome the problem, can be by three-stage electricity
Stream protection starts to obtain fault message by the delay greater than T1 again, but the program has violated the quick of current quick
Property, while increasing entire distribution protection time delay of action.After former acceleration reclosure brake scheme, current quick can examined
It measures instant of failure and quickly cuts off failure.Due to the process non-selectivity, for data window on it substantially without influence, i.e. T1 does not influence electricity
Flow velocity breaks protection act.
The basic principles, main features and advantages of the present invention have been shown and described above.The technology of the industry
Personnel only illustrate the present invention it should be appreciated that the present invention is not limited by examples detailed above described in examples detailed above and specification
Principle, various changes and improvements may be made to the invention without departing from the spirit and scope of the present invention, these variation and
Improvement all fall within the protetion scope of the claimed invention.The claimed scope of the invention is by appended claims and its is equal
Object defines.
Claims (5)
1. the active distribution network guard method of a kind of meter and region measurement capability, which comprises the steps of:
S1 establishes inverse distributed power Faults Characteristic Analysis model under power limitation control mode, after model simplification, inverter
DC voltage is kept constant;
S2 analyzes the fault characteristic of distributed generation resource and its influence to power distribution network current protection, the inversion under fault condition
The current failure characteristic of type distributed generation resource depends on the control strategy of inverter, and the step further comprises:
S21 carries out Faults Characteristic Analysis to inverse distributed power under power limitation control mode, and inverter output power is in dq
Formula under coordinate system are as follows:
Wherein, P, Q are the active power and reactive power of IIDG output;ugd、ugqFor d, q axis component of network voltage;id、iqFor
D, q axis component of inverter output current;
When d axis is oriented to network voltage vector, have:
Wherein, ugFor network voltage vector magnitude;
By above-mentioned two formulas simultaneous solution, inverter PQ control reference current is obtained are as follows:
Wherein, Pref、QrefFor the active power reference value and reactive power reference qref of IIDG;id.ref、iq.refWhen to operate normally
Watt current reference value and reactive current reference value;
In view of the inverter power element conveyance capacity of distributed generation resource is limited, if maximum output current imaxFor rated current in
α times, 1.2≤α≤1.5, i.e. imax=α in, then have:
Wherein, id.ref.f、iq.ref.fWatt current reference value and reactive current reference value when for failure;iq.ref.fBy distributed electrical
The low voltage crossing strategy decision that source is taken;
S22, analyze influence of the distributed generation resource to power distribution network current protection under fault condition: the distributed generation resource is under it
The protective device of trip helps increasing effect, and current value increases at protective device;The distributed generation resource fills the protection swum thereon
It sets, the current value that the system of will cause flows through protective device reduces;
S3, for the excellent region of power distribution network measurement capability, the structure type combined using centralization and layer-stepping builds master
Dynamic distribution protection system architecture occurs current direction in the protective device of front and back by comparing failure, completes determining for faulty line
Position;
S4, for the region of power distribution network measurement capability scarcity, using distributed generation resource it is grid-connected with distribution protection actuation time when
The active distribution network reclosing scheme of sequence cooperation.
2. the active distribution network guard method of a kind of meter as described in claim 1 and region measurement capability, it is characterised in that institute
Stating active distribution network protection system architecture in step S3 from top to bottom successively includes central processing unit, region decision package and sheet
Three levels of ground protection location,
The local protection location is installed at breaker, is moved for receiving higher level region decision package for what breaker was assigned
It orders, and then divide-shut brake control is carried out to breaker;
The region decision package is set in power distribution network subregion, setting one in each subregion, for receiving at each breaker
The current failure component direction that local protection location provides judges information, locks fault section by matrix operation, and will tripping
Order is issued to corresponding local protection location, controls corresponding circuit breaker trip by local protection location, completes fault section
Positioning and excision;
It is equipped with a central processing unit in the power distribution network and carries out overall scheduling controlling.
3. the active distribution network guard method of a kind of meter as claimed in claim 1 or 2 and region measurement capability, feature exist
In: current failure component direction uses the dual method of discrimination in " direction+amplitude " in the step S3,
" direction " method of discrimination are as follows: if current direction is constant after failure and amplitude increases, current failure component direction with
PRE-FAULT CURRENT direction is identical;If current direction changes after failure or current direction is constant and amplitude reduces, current failure
Component direction is contrary with PRE-FAULT CURRENT;
" amplitude " method of discrimination are as follows: when failure is located within the section of protection zone, section both ends current and phase difference is 0 °;When event
Barrier is located at except protection section or when no fault occurs, section both ends current and phase difference is 180 °.
4. the active distribution network guard method of a kind of meter as claimed in claim 3 and region measurement capability, it is characterised in that institute
State the positioning of faulty line in step S3 the following steps are included:
S31 carries out multidomain treat-ment by bound pair power distribution network of open type interconnection switch, 1~n is numbered to bus in region, female
2 breakers are installed between line i and bus j;
S32 is established according to the bus quantity n in Local Area Network topology and is stored n × n rank null matrix;
S33, according to current failure component direction criterion, if current failure component direction and PRE-FAULT CURRENT side at breaker i-j
To identical, then Aij=1, i ≠ j;If current failure component direction is contrary or breaking with PRE-FAULT CURRENT at breaker j-i
Fault current is not detected at device j-i, then Aij=0, i ≠ j, and then obtain fault judgment matrix DF, matrix element is as follows
It is shown:
S34, by AijWith AjiLogic XOR operation is executed, if Aij⊕Aji=0, then it can be determined that route between bus i and bus j
Normally;If Aij⊕Aji=1, then it can be determined that fault point between bus i and bus j.
5. the active distribution network guard method of a kind of meter as described in claim 1 and region measurement capability, which is characterized in that institute
Stating step S4 further comprises:
S41, fault detection: real-time detection DG and power distribution network point of common coupling voltage, once it detects since Distribution Network Failure causes
PCC voltage reduces, and disconnects the connection of DG and power distribution network immediately;
S42, distribution network protection action logic: if failure occurs to be delayed and be overlapped by Td in feeder line, the excision of the non-selectivity feeder line
The feeder line;
S43, DG grid-connected action logic again: judging fault zone, if detecting, failure occurs in PCC breaker upstream, through Tm
After delay waits power distribution network reclosing, the voltage of PCC is detected, prepares simultaneous interconnecting if meeting same period condition and shows power distribution network
Failure is transient fault, and failure has been eliminated;Or distribution network failure is permanent fault, but DG is located on distribution network failure
Trip;No matter which kind of situation, DG carries out simultaneous interconnecting operation;If being unsatisfactory for grid-connected conditions always, show that distribution network failure is
Permanent fault, and DG is located at distribution network failure downstream, and DG continues to keep off-network state.
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