CN104701827A - Microgrid wide-area current protecting system and method based on multi-Agent technology - Google Patents

Abstract

A microgrid wide-area current protecting system and method based on the multi-Agent technology belongs to the technical field of microgrid protection. The system is composed of an intelligent electronic equipment layer, an area control and protection coordinating layer and a central processing layer, wherein the intelligent electronic equipment layer is composed of intelligent electronic devices (IED) configured on every breaker in a microgrid, and every IED comprises a state monitoring Agent, a measuring Agent, an network topology Agent and a protecting Agent; the area control and protection coordinating layer comprises an area control Agent and a protection coordinating Agent; the central processing layer comprises a central processing Agent. According to the microgrid wide-area current protecting system and method based on the multi-Agent technology, the microgrid current protecting range is divided through an improved taboo fusion breadth searching algorithm, gives full play to the advantage of a taboo algorithm capable of eliminating local optimization, makes full use of the advantages of wide search range and high efficiency of a breadth search algorithm and overcomes refusal operation and maloperation of the IEDs through a method of enlarging the current protecting range, thereby being capable of accurately and rapidly cutting off faults inside the microgrid.

Description

Based on microgrid wide area current protection system and the method for multi-Agent technology

Art

The invention belongs to microgrid resist technology field, particularly a kind of microgrid wide area current protection system based on multi-Agent technology and method.

Background technology

Microgrid is by building the Miniature low voltage distribution system that is made up of a series of distributed power source (DG), energy-storage system and load, and the abundant application for distributed power source provides effect technique means.Meanwhile, the electrical characteristic that microgrid is inner more complicated: the inner direction of tide of microgrid is not fixed, and microgrid exists grid-connected and isolated island two kinds of operational modes.The selectivity that the bi-directional current characteristic of microgrid makes microgrid protect is more difficult accomplishes; Be incorporated into the power networks and islet operation be then faced with the short-circuit current differed greatly.In addition, " plug and play " characteristic that microgrid and distributed power source have, brings larger impact to the voltage of microgrid and frequency stabilization, brings stern challenge therefore to the protection of microgrid.

Along with the fast development of WAMS and communication network, the wide area current protection realized based on Wide-area Measurement Information receives the concern of Chinese scholars, and meanwhile multi-Agent technology is also applied in electric power system more and more widely.Therefore, scholars attempt a multi-Agent technology and combine with wide area current protection, and achieve some basic achievements in research.But the research of these microgrid guard methods is only limitted to specific microgrid structural model, do not possess popularity, and for wide area current protection, receiving the scope of fault message is not be the bigger the better, and reason is as follows: one is that the rapidity requirement of relaying protection makes do not have enough time to go receive and process large-scale fault message; Two is that fault disturbance only affects limited subrange, and the fault message within the scope of this is most important to breakdown judge, and information outside fault is very unimportant, thus protection range how to divide be a problem needing research further.And also exist when intelligent electronic device (IED) tripping or malfunction, the problem of IED associated therewith how action.

Summary of the invention

For the deficiency that existing method exists, the present invention proposes a kind of microgrid wide area current protection system based on multi-Agent technology and method.

Technical scheme of the present invention is achieved in that

Based on a microgrid wide area current protection system for multi-Agent technology, this system divides is intelligent electronic device layer, Region control and protection coordination layer, central processing layer totally 3 levels; Wherein:

Intelligent electronic device layer is made up of the intelligent electronic device IED that circuit breaker each in microgrid configures; Intelligent electronic device layer is responsible for the state information gathering microgrid, and draws out real-time microgrid network topological diagram, is also responsible for the electric quantity information gathering microgrid simultaneously; And when interlayer communication is normal, the real-time microgrid network topological diagram drawn is uploaded to Region control and protection coordination layer and central processing layer, the electric quantity information of microgrid is uploaded to Region control and protection coordination layer; Each described IED comprises again further:

Status monitoring Agent, is responsible for the state information of monitoring microgrid, comprises the on-position of distributed power source, folding condition that each circuit breaker in state and microgrid is moved back in the throwing of distributed power source;

Measure Agent, be responsible for gathering the electric quantity information of microgrid, comprise: the voltage of microgrid, the magnitude of current, phase angle and frequency;

Network topology Agent, is responsible for the state information according to microgrid, draws real-time microgrid network topological diagram;

Protection Agent, be responsible for the electric quantity information of microgrid is analyzed after, according to central authorities process Agent send microgrid overcurrent protection scheme adjust adaptively the Protection criteria write in advance protection definite value or when interlayer communication interrupts completely autonomous action excision fault;

Region control and protection coordination layer comprise:

Region control Agent, is responsible for the reactive power to the active power of distributed power source, distributed power source, the active power of energy-storage units, the reactive power of energy-storage units, microgrid voltage and microgrid frequency and controls, make control program;

Protection coordination Agent, determines the microgrid current protection scope that should expand of the optimum when main protection IED tripping or malfunction in microgrid; Be responsible for coordinating and managing each protection Agent, determine how the protection Agent of the superior and the subordinate's circuit of same outlet coordinates, and makes protection coordination scheme;

Central authorities' processing layer comprises:

Central authorities process Agent, is responsible for the operating state of each Agent of monitoring except central authorities process Agent; The control program that reference zone control agents provides and the protection coordination scheme that protection coordination Agent provides, make microgrid overcurrent protection scheme, and feed back to intelligent electronic device layer; When interlayer communication is normal, microgrid current protection region is divided in real time;

Described central authorities process Agent, Region control Agent and protection coordination Agent is all configured in substation low-voltage side leading-out terminal.

The fiber optic Ethernet of employing between layers of system carries out interconnected; Information exchange is carried out by CAN between different Agent in same layer.

The method of the microgrid wide area current protection system based on multi-Agent technology described in employing, comprises the steps:

Step 1, each Agent of initialization;

The microgrid state information that it monitors by step 2, status monitoring Agent in real time passes to network topology Agent; Described microgrid state information comprises: the folding condition of each circuit breaker in state and microgrid is moved back in the on-position of distributed power source, the throwing of distributed power source; Measure that Agent is also real-time passes to protection Agent by microgrid electric quantity information, described microgrid electric quantity information comprises: the voltage of microgrid, the magnitude of current, phase angle and frequency simultaneously;

If each interlayer communication of step 3 is normal, then perform step 4; If interlayer communication interrupts completely, then protect Agent to adopt and carry out failure removal based on the overcurrent protection of local information;

Step 4, according to real-time microgrid state information, network topology Agent draws real-time microgrid network topological diagram and passes to Region control Agent, protection coordination Agent and central authorities process Agent, measures that Agent is also real-time that microgrid electric quantity information is passed to Region control Agent simultaneously;

Step 5, the real-time microgrid network topological diagram drawn according to network topology Agent and measure the microgrid electric quantity information of Agent, Region control Agent formulates the control program of the active power of distributed power source in microgrid current protection region, the reactive power of distributed power source, the active power of energy-storage units, the reactive power of energy-storage units, microgrid voltage and microgrid frequency and is uploaded to central authorities process Agent; Protection coordination Agent formulates microgrid protection coordination scheme and is uploaded to central authorities process Agent;

The control program that step 6, the real-time microgrid network topological diagram drawn according to network topology Agent, Region control and protection coordination layer are made and protection coordination scheme, taboo list is introduced breadth first search method and is formed fusion taboo breadth first search method by central authorities process Agent, utilize this fusion to avoid breadth first search method to divide in real time microgrid current protection region, obtain microgrid current protection zoning;

The control program that step 7, reference zone control and scheduling co-design cooperation layer are made and protection coordination scheme, central authorities process Agent makes microgrid overcurrent protection scheme: all configure the current comparison pilot protection of a set of improvement and a set of overcurrent protection based on local information in the protection Agent in each microgrid current protection region delimited; This microgrid overcurrent protection scheme is fed back to intelligent electronic device layer by central authorities process Agent simultaneously;

Step 8, when fault message correct and complete time, by improve current comparison pilot protection carry out failure removal;

Protection Agent analyzes the microgrid electric quantity information that measurement Agent sends here; and combine the microgrid overcurrent protection scheme of central authorities process Agent transmission; the protection definite value of the current comparison pilot protection criterion of the improvement that adaptive adjustment writes in advance, comprising: the setting value I of differential current _set1, ratio brake coefficient K ₁, K ₂, the erratic current of DG is to the current comparison pilot protection influence coefficient K improved ₃and the flex point value I of ratio brake electric current _iNT, the number of gathering line road port;

The current comparison pilot protection criterion improved is as follows:

$\left\{\begin{array}{cc}{I}_d>I_{{\mathrm{set}}_1}& \\ I_d>k_1{I}_{\mathrm{zd}}& I_d\≤I_{\mathrm{INT}}\\ I_d\≥k_2(I_{\mathrm{zd}}-I_r)& I_d>I_{\mathrm{INT}}\end{array}\right.$

$I_d=k_3\left|\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\ΔI}}_{\mathrm{gi}}\right|$

$I_{\mathrm{zd}}=|\sqrt{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\ΔI}}_{\mathrm{gi}}^2}-\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{gs}}|$

$\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{gs}}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\ΔI}}_{\mathrm{gi}}$

I _r＝I _INT(k ₂-k ₁)/k ₁k ₂

Δ I in formula _gifor the magnitude of current that each line port gathers, the network topological diagram that can provide according to network topology Agent determines the number of gathering line road port, thus regulates the criterion of current comparison pilot protection adaptively; K ₁, K ₂for ratio brake coefficient, I _iNTfor the flex point value of ratio brake electric current, I _set1for the setting value of differential current, K ₃it is the coefficient that the erratic current of DG affects current comparison pilot protection;

Step 9, when partial fault loss of learning or fault message mistake, main protection IED tripping or malfunction, incidence coefficient and the protection act characteristic coefficient of the IED that the IED of this tripping or malfunction in microgrid is adjacent then is determined by protection coordination Agent, and then build current protection actuating range output function, the microgrid current protection scope disaggregation that acquisition should expand, obtain the optimum microgrid current protection actuating range that should expand by ant group algorithm optimizing again, carry out failure removal finally by the longitudinal differential current protection improved;

Determine that each IED is adjacent the incidence coefficient A of IED according to the Network Topology for Real-Time figure that network topology Agent provides, protection coordination Agent _f:

Define the operating characteristics coefficient of each IED:

Wherein i=1,2......n; K and A _fcorresponding, i.e. k=1,2,3; N is the number of IED in microgrid;

Set up current protection actuating range expression formula as follows:

$\left\{\begin{array}{cc}{A}_f=1& F_1=(R_{\mathrm{fIED}1}^1,R_{\mathrm{fIED}2}^1,\·\·\·,R_{\mathrm{fIEDn}}^1)\\ A_f=2& F_2=(R_{\mathrm{fIED}1}^2,R_{\mathrm{fIED}2}^2,\·\·\·,R_{\mathrm{fIEDn}}^2)\\ A_f=3& F_3=(R_{\mathrm{fIED}1}^3,R_{\mathrm{fIED}2}^3,\·\·\·,R_{\mathrm{fIEDn}}^3)\end{array}\right.$

And build current protection actuating range output function F _out={ F ₁, F ₂, F ₃, wherein F ₁, F ₂, F ₃protection act priority reduce successively, F ₁there is a solution, F ₂and F ₃all there is multiple solution; According to F _outoutput can determine that each IED is because of fault information errors or partial fault loss of learning, the microgrid current protection actuating range disaggregation that should expand after causing malfunction or tripping.

Utilize fusion taboo breadth first search method to carry out microgrid dividing the process obtaining microgrid current protection zoning in real time in described step 6, comprise the steps: further

Step 6.1, set up and divide the target function in microgrid current protection region, the target of this function is that in microgrid, power supply interrupted district minimizes, and sets up constraints for this target function;

Described target function is: $\begin{array}{cc}\mathrm{Min}& F\left(x\right)=\underset{i\∈\mathrm{ps}}{\mathrm{\Σ}}{A}_i\end{array}$

Described constraints is:

$\left\{\begin{array}{c}{T}_{\mathrm{ij}}=\frac{I_{\mathrm{ij}}}{C}+{\mathrm{mt}}_v+\mathrm{\Δt}\≤T_{\mathrm{ijm}}\\ B_{\min }\≤B\≤B_{\max }\\ P_i=(P_{X1}\∪P_{X2}......)\∩(P_{y1}\∪P_{y2}......)\≥P_{\mathrm{im}}\\ U_{\min }\≤U\≤U_{\max }\end{array}\right.$

Wherein F (x) represents total power failure area; A _irepresent the power failure area of each zoning; PS represents the measure collection making each zoning power failure area minimum; T _ijthe representing fault information delay time; I _ijto represent in microgrid node i to the communication distance of node j; C represents the light velocity; M represents the nodal point number of communication path process; t _vrepresent the call duration time of single node; Δ t represents randomized jitter time delay; T _ijmthe set-point of representing fault information delay; B representing fault information gathering amount; P _irepresent communication reliability degree; P _xirepresent the reliability of communication device; P _yirepresent the reliability of circuit between communication device; P _imrepresent the set-point of communication reliability; I=1,2......n, j=1,2......n, U represent microgrid busbar voltage;

Step 6.2, employing breadth first search method, and provide the initial solution of breadth first search, namely initial microgrid current protection zoning, this initial solution can be produced by random device or be produced by existing heuristic;

Step 6.3, with the above-mentioned constraints provided for boundary, utilize breadth first search method from initial solution, search for the optimal solution of above-mentioned target function;

Step 6.4, the locally optimal solution searched is put into taboo list; taboo list all upgrades in each iteration; this locally optimal solution is avoided during search next time; and other space is searched for; until acquisition globally optimal solution, till namely meeting the optimum microgrid current protection zoning of above-mentioned target function and constraints.

The invention has the beneficial effects as follows:

1, the system of the microgrid wide area current protection based on multi-Agent technology of layering is built.This protection system takes full advantage of the independence of Agent, interactivity and cooperative, changeability and adaptability, spontaneity, both centralized decision-making can carry out protecting control, again can when communication failure, independently protects.

2, the fusion taboo breadth first search method improved is adopted to divide microgrid current protection scope, give full play to Tabu search algorithm and there is the advantage breaking away from local optimum, introduce taboo list to mark the locally optimal solution obtained with specification breadth first search, prevent breadth first search's result to be absorbed in local optimum, save search time simultaneously; This algorithm also takes full advantage of that breadth first search method hunting zone is wide, efficiency is high, the simple advantage of algorithm, therefore merges taboo breadth first search method and can well obtain target optimal solution, namely optimum microgrid current protection scope.

3, the current comparison pilot protection improved is adopted; the network topological diagram that protection coordination Agent can provide according to network topology Agent is determined to protect the current comparison pilot protection improved in Agent to want the number of gathering line road port; thus protection Agent can the Protection criteria of adaptive adjustment current comparison pilot protection, to overcome the impact of DG " plug and play " on protection.

4, the method expanding current protection scope is adopted to overcome IED tripping or malfunction; first determine incidence coefficient and the protection act characteristic coefficient of each IED; and then constructor determines that the microgrid current protection actuating range disaggregation that should expand, the method finally by ant optimization determine the optimum microgrid current protection actuating range that should expand.This method can overcome the problem that IED tripping or malfunction bring effectively, correctly can excise the fault of microgrid inside fast.

Accompanying drawing explanation

Fig. 1 is the microgrid wide area current protection system structural representation based on multi-Agent technology of one embodiment of the present invention;

Fig. 2 is the microgrid wide area current protection flow chart based on multi-Agent technology of one embodiment of the present invention;

Fig. 3 is the fusion taboo breadth first search method flow chart of one embodiment of the present invention;

Fig. 4 is the microgrid wide area current protection allocation plan based on multi-Agent technology of one embodiment of the present invention;

Fig. 5 (a) is that one embodiment of the present invention, at the current comparison pilot protection line FG improved, current waveform figure before and after three phase short circuit fault occurs; B () is that one embodiment of the present invention, at the current comparison pilot protection line FG improved, current waveform figure before and after single phase ground fault occurs;

Fig. 6 is that the ant optimization algorithm that utilizes of one embodiment of the present invention finds optimum expansion current protection scope flow chart.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail.

Present embodiment builds the wide area current protection system based on multi-Agent technology of layering, as shown in Figure 1.

This system divides is intelligent electronic device layer, Region control and protection coordination layer and central processing layer.Carry out information exchange by fiber optic Ethernet networking between layers, the mechanism of information exchange adopts IEC61850 GOOSE model.Information exchange is carried out by CAN (controller local area network) bus between different Agent in same layer; Each circuit breaker configures a set of intelligent electronic device (IED) in microgrid, all IED form intelligent electronic device layer; Intelligent electronic device layer is for the state information that gathers in microgrid and draw out real-time microgrid network topological diagram, also gather electric quantity information simultaneously, in the normal situation of interlayer communication, the information of carrying out is uploaded, make final decision by central processing layer, independently when interlayer communication interrupts completely carry out faulted-phase judgment and protection act; Each IED comprises network topology Agent, status monitoring Agent, measures Agent and protection Agent.Region control and protection coordination layer: the local information provided according to decision-making and the intelligent electronic device layer of central processing layer, the reactive power of the active power of the reactive power of the active power of distributed power source, distributed power source, energy-storage units, energy-storage units, microgrid voltage and microgrid frequency are controlled, microgrid frequency stabilization, voltage are normal to reach, the object of power-balance; Meanwhile, when partial fault loss of learning or fault message mistake cause main protection IED tripping or malfunction, determine in microgrid with the incidence coefficient of this tripping or the adjacent each IED of malfunction IED and protection act characteristic coefficient, thus determine the microgrid current protection scope that should expand, determine the optimum microgrid current protection scope that should expand finally by ant group algorithm optimizing; Coordinate and manage each protection Agent in microgrid, how the protection Agent as the superior and the subordinate's circuit determining same outlet coordinates; Determine to protect the current comparison pilot protection improved in Agent to want the number of gathering line road port according to the real-time topology figure that network topology Agent draws; This layer comprises Region control Agent and protection coordination Agent, is all configured in substation low-voltage side leading-out terminal.Central authorities' processing layer: for overall monitoring all Agent than itself; and when communicating normal, microgrid current protection region is divided in real time; and make microgrid overcurrent protection scheme, this layer comprises central authorities process Agent, is also configured in substation low-voltage side leading-out terminal.When interlayer communication is normal, intelligent electronic device layer, Region control and protection coordination layer and central processing layer can carry out the transmission of order and the feedback of information; When interlayer communication interrupts completely, intelligent electronic device layer can make full use of the independence handling failure information of Agent and carry out current protection action.

Central authorities process Agent is responsible for the operating state of each Agent monitored except self; With intelligent electronic device layer, communicate between Region control with protection coordination layer, the control program of the active power of the active power to distributed power source that reference zone control agents provides, the reactive power of distributed power source, energy-storage units, the reactive power of energy-storage units, microgrid voltage and microgrid frequency, the protection coordination scheme to each protection Agent that protection coordination Agent provides, carry out analysis and make microgrid overcurrent protection scheme, and process with the central authorities of other microgrid and carry out communicating between Agent and mutual; Be responsible for the information processing of each Agent, the full microgrid fault message that comprehensive each Agent sends here, carries out preserving and showing, and forms failure logging form; When communicating normal, microgrid current protection region is divided in real time.

Region control Agent and protection coordination Agent is an intermediate link; it is the joint of information; information interaction should be carried out with intelligent electronic device layer; also information interaction to be carried out with central processing layer; wherein Region control Agent is responsible for active power to distributed power source, the reactive power of distributed power source, the active power of energy-storage units, the reactive power of energy-storage units, microgrid voltage and microgrid frequency and controls, and to reach, microgrid frequency stabilization, voltage are normal, the object of power-balance.Protection coordination Agent determines to protect the current comparison pilot protection of the improvement in Agent to want the number of gathering line road port according to the real-time microgrid network topological diagram that network topology Agent draws; When partial fault loss of learning or fault message mistake cause main protection IED tripping or malfunction, determine in microgrid with the incidence coefficient of this tripping or the adjacent each IED of malfunction IED and protection act characteristic coefficient, thus determine the microgrid current protection scope that should expand, determine the optimum microgrid current protection scope that should expand finally by ant group algorithm optimizing; Being responsible for coordinating and managing each protection Agent, as determined how coordinating of the protection Agent of the superior and the subordinate's circuit of same outlet, formulating protection coordination scheme.And the control program of formulation and protection coordination scheme are uploaded to central authorities process Agent, process Agent by central authorities and make microgrid overcurrent protection scheme as a reference.

In intelligent electronic device layer: status monitoring Agent is responsible for monitoring the state information of microgrid, microgrid state information comprises: the folding condition of each circuit breaker in state and microgrid is moved back in the on-position of distributed power source, the throwing of distributed power source, and communicates with network topology Agent; Measure the collection that Agent realizes the electric parameters that microgrid current protection needs, data on real-time measurement current transform er, voltage transformer, or measure the amplitude of protected area voltage, the amplitude of electric current, phase angle and frequency by synchronous phasor measuring device, directly with between protection Agent communicate, also communicate with Region control Agent simultaneously; Protection Agent major function have: be responsible for the electric quantity information of microgrid is analyzed after; the microgrid overcurrent protection scheme sent in conjunction with central authorities process Agent adjusts the protection definite value of the improvement current comparison pilot protection criterion write in advance adaptively or adopts when interlayer communication interrupts completely the overcurrent protection autonomous action based on local information to excise fault, and protection definite value comprises: the setting value I of differential current _set1, ratio brake coefficient K ₁, K ₂, the erratic current of DG is to current comparison pilot protection influence coefficient K ₃and the flex point value I of ratio brake electric current _iNT; The state information real-time rendering that network topology Agent provides according to status monitoring Agent goes out network topological diagram, and is uploaded to Region control Agent, protection coordination Agent and central authorities process Agent.

The microgrid wide area current protection method based on multi-Agent technology of present embodiment, as shown in Figure 2.

Step 1, by each Agent initialization in microgrid.

The microgrid state information that it monitors by step 2, status monitoring Agent in real time passes to network topology Agent; Described microgrid state information comprises: the folding condition of each circuit breaker in state and microgrid is moved back in the on-position of distributed power source, the throwing of distributed power source; Measure that Agent is also real-time passes to protection Agent by microgrid electric quantity information, described microgrid electric quantity information comprises: the voltage of microgrid, the magnitude of current, phase angle and frequency simultaneously.

If each interlayer communication of step 3 is normal, then perform step 4; If interlayer communication interrupts completely, then protect Agent to adopt and carry out failure removal based on the overcurrent protection of local information;

Step 4, according to real-time microgrid state information; network topology Agent draws real-time microgrid network topological diagram and passes to Region control Agent, protection coordination Agent and central authorities process Agent, measures that Agent is also real-time that microgrid electric quantity information is passed to Region control Agent simultaneously.

Step 5, to draw real-time microgrid network topological diagram and measure the microgrid electric quantity information of Agent according to network topology Agent, Region control Agent formulates the control program of the active power of distributed power source in microgrid current protection region, the reactive power of distributed power source, the active power of energy-storage units, the reactive power of energy-storage units, microgrid voltage and microgrid frequency and is uploaded to central authorities process Agent; Protection coordination Agent formulates microgrid protection coordination scheme and is uploaded to central authorities process Agent, and central authorities process Agent makes microgrid overcurrent protection scheme with reference to microgrid protection coordination scheme and control program, and feeds back to intelligent electronic device layer;

As shown in Figure 4: when PCC closes, when microgrid runs in grid-connected mode, distributed power source DG1, DG2 in microgrid all adopt P-Q (active power-reactive power) to control, to ensure the output of power, and energy-storage units also adopts P-Q to control, when the voltage of microgrid or frequency change, the operating point of DG1 and DG2 can change the constant of the active reactive ensureing to export, the operating point of energy-storage units also can change simultaneously, carries out " peak load shifting " to ensure the balance of whole microgrid active power and reactive power; When PCC disconnects microgrid, when running in isolated island mode, energy storage device in microgrid adopts V-F (voltage-frequency) to control, maintain the stable of microgrid voltage and frequency, distributed power source DG1 and DG2 still adopts P-Q to control to ensure the output of power, when the voltage of microgrid or frequency change, the energy-storage units adopting V-F to control can adopt the mode of translation operation curve to maintain the stable of microgrid voltage and frequency, and DG1, DG2 of adopting P-Q to control still can adopt the mode changing operating point to ensure that the output of active power and reactive power does not change.

Protection coordination scheme is formulated for circuit EF, when circuit EF breaks down, protection Agent in main protection IED9 and IED10 sends trip command and acts on corresponding circuit breaker, send tripping operation information to protection coordination Agent simultaneously, protection coordination Agent is after certain time-delay, detect corresponding circuit breaker respectively by the status monitoring Agent in status monitoring Agent and IED10 of IED9 whether to disconnect, if due to IED9 and IED10 tripping cause its separately corresponding circuit breaker do not disconnect, then the protection coordination Agent microgrid current protection scope that should expand according to optimum sends tripping operation information to the protection Agent in IED corresponding to the protection Agent in IED corresponding to higher level's circuit AE or subordinate circuit FG, trip command cut-off breaker is sent by the protection Agent in corresponding IED, by failure removal.

Step 6, grid of reference topology Agent draws the control program and protection coordination scheme that real-time microgrid network topological diagram, Region control and protection coordination layer make, taboo list is introduced breadth first search method and is formed fusion taboo breadth first search method by central authorities process Agent, utilize this fusion to avoid breadth first search method to divide in real time microgrid current protection region, obtain microgrid current protection zoning;

Wherein merge taboo breadth first search method flow chart as shown in Figure 3, comprise the following steps:

Step 6.1, set up and divide the target function in microgrid current protection region, the target of this function is that in microgrid, power supply interrupted district minimizes, and sets up constraints for this target function;

Described target function is: $\begin{array}{cc}\mathrm{Min}& F\left(x\right)=\underset{i\∈\mathrm{ps}}{\mathrm{\Σ}}{A}_i\end{array}$

Described constraints is:

Transmitting fault information postpones to be less than or equal to fault message time delay set-point, namely communication reliability is more than or equal to reliability set-point, i.e. P _i=(P _x1∪ P _x2...) ∩ (P _y1∪ P _y2...)>=P _im; And voltage constraints U _min≤ U≤U _maxwith fault information acquisition amount constraints B _min≤ B≤B _maxfor boundary, wherein U _maxand U _minbe respectively 1.1U and 0.9U, B _maxand B _minbe respectively 1.2B and 0.8B; F (x) represents total power failure area; A _irepresent the power failure area of each zoning; PS represents the measure collection making each zoning power failure area minimum; T _ijthe representing fault information delay time; I _ijto represent in microgrid node i to the communication distance of node j; C represents the light velocity; M represents the nodal point number of communication path process; t _vrepresent the call duration time of single node; Δ t represents randomized jitter time delay; T _ijmthe set-point of representing fault information delay; B representing fault information gathering amount; P _irepresent communication reliability degree; P _xirepresent the reliability of communication device; P _yirepresent the reliability of circuit between communication device; P _imrepresent the set-point of communication reliability; I=1,2......n, j=1,2......n, U represent microgrid busbar voltage;

Step 6.2, employing breadth first search method, and provide the initial solution of breadth first search, namely initial microgrid current protection zoning, this initial solution can be produced by random device or be produced by existing heuristic;

Step 6.3, with the above-mentioned constraints provided for boundary, utilize breadth first search method from initial solution, search for the optimal solution of above-mentioned target function.

Step 6.4, the locally optimal solution searched is put into taboo list; taboo list all upgrades in each iteration; this locally optimal solution is avoided during search next time; and other space is searched for; until acquisition globally optimal solution, till namely meeting the optimum microgrid current protection zoning of above-mentioned target function and constraints.

As shown in Figure 4: the optimum microgrid current protection zoning utilizing above-mentioned fusion taboo breadth first search method at a time to divide, comprising: current protection region I, current protection region II, current protection region III, current protection region IV, current protection region V and current protection region VI.Wherein current protection region I comprises the points of common connection (PCC) of transformer station, microgrid and power distribution network; Current protection region II comprises whole feeder line L1, load LOAD1 and energy-storage units; Current protection region III comprises AC section, the load LOAD2 and the first distributed power source DG1 of feeder line L2; Current protection region IV comprises remainder and the load LOAD3 of the feeder line L2 except AC section; Current protection region V comprises the AE section of feeder line L3, EF section, FG section, load LOAD4, load LOAD5, load LOAD6 and the second distributed power source DG2; Current protection region VI comprises feeder line L3 remainder except AE section, EF section, FG section and load LOAD7.Can coordinate between above-mentioned all current protection regions, thus reach the object of correct, quick excision microgrid internal fault.

Step 7, delimit each microgrid current protection region in protection Agent in all configure the current comparison pilot protection of a set of improvement and a set of overcurrent protection based on local information;

Step 8, when fault message correct and complete time, by improve current comparison pilot protection carry out failure removal;

For the circuit FG in the microgrid current protection region V shown in Fig. 4, protection coordination Agent is according to the access state of DG2 in network topology, determine to protect the current comparison pilot protection improved in Agent will gather the magnitude of current of 3 end lines, protection coordination Agent judges IED11 according to network topology, IED12, IED16 is relevant to the protection of circuit FG, the measurement Agent of each IED inside is allowed to communicate with protection Agent, protection Agent analyzes the microgrid electric quantity information that measurement Agent sends here, and according to the microgrid overcurrent protection scheme that central authorities process Agent sends, the protection definite value of the current comparison pilot protection criterion of the improvement that adaptive adjustment writes in advance, comprise: the setting value I of differential current _set1, ratio brake coefficient K ₁, K ₂, the erratic current of DG is to the current comparison pilot protection influence coefficient K improved ₃and the flex point value I of ratio brake electric current _iNT,

The current comparison pilot protection criterion improved is as follows:

$\left\{\begin{array}{cc}{I}_d>I_{{\mathrm{set}}_1}& \\ I_d>k_1{I}_{\mathrm{zd}}& I_d\≤I_{\mathrm{INT}}\\ I_d\≥k_2(I_{\mathrm{zd}}-I_r)& I_d>I_{\mathrm{INT}}\end{array}\right.$

$I_d=k_3\left|\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\ΔI}}_{\mathrm{gi}}\right|$

$I_{\mathrm{zd}}=|\sqrt{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\ΔI}}_{\mathrm{gi}}^2}-\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{gs}}|$

$\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{gs}}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\ΔI}}_{\mathrm{gi}}$

I _r＝I _INT(k ₂-k ₁)/k ₁k ₂

Δ I in formula _gifor the magnitude of current that each line port gathers, the network topological diagram that can provide according to network topology Agent determines the number of gathering line road port, thus the criterion of the current comparison pilot protection of Automatic adjusument improvement, to overcome the impact of DG " plug and play " on protection; K ₁, K ₂for ratio brake coefficient, I _iNTfor the flex point value of ratio brake electric current, I _set1for the setting value of differential current, K ₃consider the coefficient of the erratic current of DG on the current comparison pilot protection impact improved;

Under PSCAD/EMTDC environment, build microgrid model, and emulate when there is single phase ground fault under there is three-phase fault and island operation state to circuit FG under the state of being incorporated into the power networks, the design parameter in microgrid model is as shown in the table.

Distributed power source	Type	Control mode	Rated power	Rated voltage
					DG1	Photovoltaic cell	P-Q controls	10KW	400V
DG2	Wind-driven generator	P-Q controls	7.5KW	400V

Table 1 distributed electrical source dates

Circuit

Length (km)

R(Ω/km)

X(Ω/km)

AB	3.45	0.126	0.154
				AC	3.40	0.126	0.154
CD	3.40	0.126	0.154
				AE	3.35	0.133	0.167
EF	3.35	0.133	0.167
				FG	3.35	0.133	0.167
GH	3.35	0.133	0.167

Table 2 line parameter circuit value

Load	Type	Capacity (KVA)	Power factor
				LOAD1	Static load	600	0.991
LOAD2	Static load	600	0.992
				LOAD3	Static load	650	0.992
LOAD4	Static load	600	0.990
				LOAD5	Static load	650	0.993
LOAD6	Static load	650	0.991
				LOAD7	Static load	600	0.992

Table 3 load parameter

The capacity arranging energy-storage units is 1000KVA, and power factor is 0.991, for P-Q controls under the state of being incorporated into the power networks, for V-F controls under island operation state.In this emulation, all DG all access, and when 0.2S, three phase short circuit fault and single phase ground fault occur respectively, duration 0.05S, and the current waveform profile of emulation is respectively as shown in Fig. 5 (a) He Fig. 5 (b).When after 0.2S input fault enabling signal, the electric current on circuit FG there occurs significant sudden change, and the current comparison pilot protection of improvement hereinbefore subsequently starts action, is excised by faulty line.The current waveform profile figure of emulation proves that the current comparison pilot protection improved can excise microgrid internal wiring fault correctly, fast.

Step 9, when partial fault loss of learning or fault message mistake, main protection IED tripping or malfunction, then by protection coordination Agent determine in microgrid with the incidence coefficient of this tripping or adjacent each IED of malfunction IED and protection act characteristic coefficient, and then build current protection actuating range output function, the microgrid current protection scope disaggregation that acquisition should expand, obtain the optimum microgrid current protection actuating range that should expand by ant group algorithm optimizing again, carry out failure removal finally by the current comparison pilot protection improved;

For the IED9 in microgrid current protection region V in Fig. 4.First determine IED associated with it: with IED9 incidence coefficient be 1 (1 represent correlation degree maximum) be IED8, IED10; With IED9 incidence coefficient be 2 (2 represent correlation degree larger) be IED7, IED11; With IED9 incidence coefficient be 3 (3 represent correlation degree minimum) be IED12.The operating characteristics coefficient of each IED is-1,0,1, namely malfunction, be failure to actuate, correct operation.

Break down with the circuit EF in microgrid current protection region V in Fig. 4, IED9 is that research object is further described.When the operating characteristics coefficient of IED9 is 1, namely during correct operation, first search and its incidence coefficient are the IED of 1, i.e. IED10.When the operating characteristics coefficient of this IED is also 1, i.e. F _out=F ₁=(... ..1,1......) time, just correctly can excise faulty line.Protection range now between IED9, IED10 is exactly optimal current protection range.When the operating characteristics coefficient of IED10 is not 1, namely protect IED malfunction or tripping.Due to the fault message mistake that IED9 can not receive fault message or receives, current protection actuating range will be expanded, go to search with IED9 incidence coefficient be 2 or 3 all IED, and the protective feature coefficient of IED9 also may not be 1, i.e. false protection or tripping.Therefore the current protection actuating range disaggregation that should expand; comprise: (IED9; IED11), (IED9; IED12), (IED8, IED10), (IED7, IED10), (IED8; IED11), (IED8; IED12), (IED7, IED11) and (IED7, IED12).So now F _out=F ₂or F _out=F ₃protection act area Results have multiple.Next present embodiment utilizes the algorithm of ant optimization to go to find the optimum current protection actuating range that should expand.

Present embodiment as shown in Figure 6 obtains the optimum microgrid current protection actuating range that should expand by ant group algorithm optimizing, comprises the following steps:

Step 9.1, initiation parameter, comprising: the greatest iteration number N of ant group _max=300, pheromones significance level factor-alpha=1, heuristic function significance level factor-beta=4, pheromones volatilization factor ρ=0.5, pheromone release total amount Q=64, the number m=30 of ant group.Definition IED action more correctly, quicker, pheromone concentration is larger.

Step 9.2, for the current protection actuating range disaggregation (IED9 that should expand determined, IED11), (IED9, IED12), (IED8, IED10), (IED7, IED10), (IED8, IED11), (IED8, IED12), (IED7, IED11), (IED7, IED12), random for each ant is placed in different starting point, namely different initial values is arranged to ant group algorithm, by all current protection actuating ranges that each should expand, that is: (IED9, IED11), (IED9, IED12), (IED8, IED10), (IED7, IED10), (IED8, IED11), (IED8, IED12), (IED7, IED11), (IED7, IED12) each node is defined as, each ant is allowed to calculate as follows, to determine the node (node that state transition probability is the highest) that its next one will be accessed, until all ants have accessed all nodes.

$P_{\mathrm{ij}}^k=\left\{\begin{array}{cc}\frac{{\left[{\mathrm{\τ}}_{\mathrm{ij}}\left(t\right)\right]}^{\mathrm{\α}}\·{\left[{\mathrm{\η}}_{\mathrm{ij}}\left(t\right)\right]}^{\mathrm{\β}}}{\underset{s\∈{\mathrm{allow}}_k}{\mathrm{\Σ}}{\left[{\mathrm{\τ}}_{\mathrm{is}}\left(t\right)\right]}^{\mathrm{\α}}\·{\left[{\mathrm{\η}}_{\mathrm{is}}\left(t\right)\right]}^{\mathrm{\β}}}& s\∈{\mathrm{allow}}_k\\ 0& s\∉{\mathrm{allow}}_k\end{array}\right.$

Wherein, represent that ant k transfers to the state transition probability of next node j (j=1,2......n) from present node i (i=1,2......n), τ _ijt () represents the pheromones amount that t is residual in node i and node j line; η _ijt () is heuristic function, represent that ant transfers to the expected degree of node j from node i, η _ij(t)=1/d _ij, d _ijfor the distance between node i to node j; Allow _k(k=1,2 ... m) be the current protection actuating range set that should expand that ant k is to be visited, during beginning, allow _kin have (n-1) individual element, namely comprise other all nodes except ant k starting point, along with the propelling of time, allow _kin element constantly reduce, until be empty, namely represent that all current protection actuating ranges that should expand all are accessed complete; α is the pheromones significance level factor, and its value is larger, represents that pheromone concentration role in transfer is larger; β is the heuristic function significance level factor, and its value is larger, and represent that the effect of heuristic function in transfer is larger, namely ant can transfer to the maximum path of pheromone concentration with larger probability.

Step 9.3, calculate the path L of each ant process _k(k=1,2 ... 30), the terminal corresponding to path that in record current iteration number of times, pheromone concentration is maximum, the current protection actuating range that the optimum namely in current iteration number of times should expand.Meanwhile, the pheromone concentration on each node access path is upgraded as follows.

τ _ij(t+n)＝(1-ρ)τ _ij(t)+Δτ _ij(t)

${\mathrm{\Δ\τ}}_{\mathrm{ij}}\left(t\right)=\underset{k=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{\Δ\τ}}_{\mathrm{ij}}^k\left(t\right)$

τ _ij(t+n) representative is through the pheromone concentration in n moment, represent that a kth ant is stayed in current iteration and separate i to the pheromones increment separated on j path, Δ τ _ijt () represents that all ants stay the pheromones increment in this path in current iteration.

If step 9.4 iterations N < is N _max=300, then make N=N+1, empty the record sheet of ant through path, and return step step 12.2; Otherwise stop calculating, export optimal solution, the path that namely pheromone concentration is maximum, terminal corresponding to this path is exactly the current protection actuating range that optimum should expand.The current protection actuating range that can obtain should expanding in present embodiment by the computing of above-mentioned ant optimization algorithm is (IED8, IED11).

Can be found out by above analysis and simulation: the isolation that the microgrid wide area current protection that the present invention is based on multi-Agent technology can be quick, correct and excision microgrid internal fault.

Claims (4)

1. based on a microgrid wide area current protection system for multi-Agent technology, it is characterized in that: this system divides is intelligent electronic device layer, Region control and protection coordination layer, central processing layer totally 3 levels; Wherein:

Intelligent electronic device layer is made up of the intelligent electronic device IED that circuit breaker each in microgrid configures; Intelligent electronic device layer is responsible for the state information gathering microgrid, and draws out real-time microgrid network topological diagram, is also responsible for the electric quantity information gathering microgrid simultaneously; And when interlayer communication is normal, the real-time microgrid network topological diagram drawn is uploaded to Region control and protection coordination layer and central processing layer, the electric quantity information of microgrid is uploaded to Region control and protection coordination layer; Each described IED comprises again further:

Status monitoring Agent, is responsible for the state information of monitoring microgrid, comprises the on-position of distributed power source, folding condition that each circuit breaker in state and microgrid is moved back in the throwing of distributed power source;

Measure Agent, be responsible for gathering the electric quantity information of microgrid, comprise: the voltage of microgrid, the magnitude of current, phase angle and frequency;

Network topology Agent, is responsible for the state information according to microgrid, draws real-time microgrid network topological diagram;

Protection Agent, be responsible for the electric quantity information of microgrid is analyzed after, according to central authorities process Agent send microgrid overcurrent protection scheme adjust adaptively the Protection criteria write in advance protection definite value or when interlayer communication interrupts completely autonomous action excision fault;

Region control and protection coordination layer comprise:

Region control Agent, is responsible for the reactive power to the active power of distributed power source, distributed power source, the active power of energy-storage units, the reactive power of energy-storage units, microgrid voltage and microgrid frequency and controls, make control program;

Protection coordination Agent, determines the microgrid current protection scope that should expand of the optimum when main protection IED tripping or malfunction in microgrid; Be responsible for coordinating and managing each protection Agent, determine how the protection Agent of the superior and the subordinate's circuit of same outlet coordinates, and makes protection coordination scheme;

Central authorities' processing layer comprises:

Central authorities process Agent, is responsible for the operating state of each Agent of monitoring except central authorities process Agent; The control program that reference zone control agents provides and the protection coordination scheme that protection coordination Agent provides, make microgrid overcurrent protection scheme, and feed back to intelligent electronic device layer; When interlayer communication is normal, microgrid current protection region is divided in real time;

Described central authorities process Agent, Region control Agent and protection coordination Agent is all configured in substation low-voltage side leading-out terminal.

2. the microgrid wide area current protection system based on multi-Agent technology according to claim 1, is characterized in that: the fiber optic Ethernet of employing between layers of system carries out interconnected; Information exchange is carried out by CAN between different Agent in same layer.

3. adopt the method for the microgrid wide area current protection system based on multi-Agent technology according to claim 1, it is characterized in that: comprise the steps:

Step 1, each Agent of initialization;

The microgrid state information that it monitors by step 2, status monitoring Agent in real time passes to network topology Agent; Described microgrid state information comprises: the folding condition of each circuit breaker in state and microgrid is moved back in the on-position of distributed power source, the throwing of distributed power source; Measure that Agent is also real-time passes to protection Agent by microgrid electric quantity information, described microgrid electric quantity information comprises: the voltage of microgrid, the magnitude of current, phase angle and frequency simultaneously;

If each interlayer communication of step 3 is normal, then perform step 4; If interlayer communication interrupts completely, then protect Agent to adopt and carry out failure removal based on the overcurrent protection of local information;

Step 4, according to real-time microgrid state information, network topology Agent draws real-time microgrid network topological diagram and passes to Region control Agent, protection coordination Agent and central authorities process Agent, measures that Agent is also real-time that microgrid electric quantity information is passed to Region control Agent simultaneously;

Step 5, the real-time microgrid network topological diagram drawn according to network topology Agent and measure the microgrid electric quantity information of Agent, Region control Agent formulates the control program of the active power of distributed power source in microgrid current protection region, the reactive power of distributed power source, the active power of energy-storage units, the reactive power of energy-storage units, microgrid voltage and microgrid frequency and is uploaded to central authorities process Agent; Protection coordination Agent formulates microgrid protection coordination scheme and is uploaded to central authorities process Agent;

The control program that step 6, the real-time microgrid network topological diagram drawn according to network topology Agent, Region control and protection coordination layer are made and protection coordination scheme, taboo list is introduced breadth first search method and is formed fusion taboo breadth first search method by central authorities process Agent, utilize this fusion to avoid breadth first search method to divide in real time microgrid current protection region, obtain microgrid current protection zoning;

The control program that step 7, reference zone control and scheduling co-design cooperation layer are made and protection coordination scheme, central authorities process Agent makes microgrid overcurrent protection scheme: all configure the current comparison pilot protection of a set of improvement and a set of overcurrent protection based on local information in the protection Agent in each microgrid current protection region delimited; This microgrid overcurrent protection scheme is fed back to intelligent electronic device layer by central authorities process Agent simultaneously;

Step 8, when fault message correct and complete time, by improve current comparison pilot protection carry out failure removal;

Protection Agent analyzes the microgrid electric quantity information that measurement Agent sends here; and combine the microgrid overcurrent protection scheme of central authorities process Agent transmission; the protection definite value of the current comparison pilot protection criterion of the improvement that adaptive adjustment writes in advance, comprising: the setting value I of differential current _set1, ratio brake coefficient K ₁, K ₂, the erratic current of DG is to the current comparison pilot protection influence coefficient K improved ₃and the flex point value I of ratio brake electric current _iNT, the number of gathering line road port;

The current comparison pilot protection criterion improved is as follows:

$\left\{\begin{array}{cc}{I}_d>I_{{\mathrm{set}}_1}& \\ I_d>k_1{I}_{\mathrm{zd}}& I_d\&le;I_{\mathrm{INT}}\\ I_d\&GreaterEqual;k_2(I_{\mathrm{zd}}-I_r)& I_d>I_{\mathrm{INT}}\end{array}\right.$

$I_d=k_3\left|\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{I}_{\mathrm{gi}}\right|$

$I_{\mathrm{zd}}=|\sqrt{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{I}_{\mathrm{gi}}^2}-\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{\mathrm{gs}}|$

$\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{\mathrm{gs}}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{I}_{\mathrm{gi}}$

I _r＝I _INT(k ₂-k ₁)/k ₁k ₂

Δ I in formula _gifor the magnitude of current that each line port gathers, the network topological diagram that can provide according to network topology Agent determines the number of gathering line road port, thus regulates the criterion of current comparison pilot protection adaptively; K ₁, K ₂for ratio brake coefficient, I _iNTfor the flex point value of ratio brake electric current, I _set1for the setting value of differential current, K ₃it is the coefficient that the erratic current of DG affects current comparison pilot protection;

Step 9, when partial fault loss of learning or fault message mistake, main protection IED tripping or malfunction, incidence coefficient and the protection act characteristic coefficient of the IED that the IED of this tripping or malfunction in microgrid is adjacent then is determined by protection coordination Agent, and then build current protection actuating range output function, the microgrid current protection scope disaggregation that acquisition should expand, obtain the optimum microgrid current protection actuating range that should expand by ant group algorithm optimizing again, carry out failure removal finally by the longitudinal differential current protection improved;

Determine that each IED is adjacent the incidence coefficient A of IED according to the Network Topology for Real-Time figure that network topology Agent provides, protection coordination Agent _f:

Define the operating characteristics coefficient of each IED:

Wherein i=1,2......n; K and A _fcorresponding, i.e. k=1,2,3; N is the number of IED in microgrid;

Set up current protection actuating range expression formula as follows:

$\left\{\begin{array}{cc}{A}_f=1& F_1=(R_{\mathrm{fIED}1}^1,R_{\mathrm{fIED}2}^1,...,R_{\mathrm{fIEDn}}^1)\\ A_f=2& F_2=(R_{\mathrm{fIED}1}^2,R_{\mathrm{fIED}2}^2,...,R_{\mathrm{fIEDn}}^2)\\ A_f=3& F_3=(R_{\mathrm{fIED}1}^3,R_{\mathrm{fIED}2}^3,...,R_{\mathrm{fIEDn}}^3)\end{array}\right.$

And build current protection actuating range output function F _out={ F ₁, F ₂, F ₃, wherein F ₁, F ₂, F ₃protection act priority reduce successively, F ₁there is a solution, F ₂and F ₃all there is multiple solution; According to F _outoutput can determine that each IED is because of fault information errors or partial fault loss of learning, the microgrid current protection actuating range disaggregation that should expand after causing malfunction or tripping.

4. the microgrid wide area current protection method based on multi-Agent technology according to claim 3; it is characterized in that: utilize fusion taboo breadth first search method to carry out microgrid dividing the process obtaining microgrid current protection zoning in real time in described step 6, comprise the steps: further

Step 6.1, set up and divide the target function in microgrid current protection region, the target of this function is that in microgrid, power supply interrupted district minimizes, and sets up constraints for this target function;

Described target function is: $\begin{array}{cc}\mathrm{Min}& F\left(x\right)=\underset{i\&Element;\mathrm{ps}}{\mathrm{\&Sigma;}}{A}_i\end{array}$

Described constraints is:

$\left\{\begin{array}{c}{T}_{\mathrm{ij}}=\frac{I_{\mathrm{ij}}}{C}+{\mathrm{mt}}_v+\mathrm{\&Delta;t}\&le;T_{\mathrm{ijm}}\\ B_{\min }\&le;B\&le;B_{\max }\\ P_i=(P_{X1}\&cup;P_{X2}......)\&cap;(P_{y1}\&cup;P_{y2}......)\&GreaterEqual;P_{\mathrm{im}}\\ U_{\min }\&le;U\&le;U_{\max }\end{array}\right.$

Wherein F (x) represents total power failure area; A _irepresent the power failure area of each zoning; PS represents the measure collection making each zoning power failure area minimum; T _ijthe representing fault information delay time; I _ijto represent in microgrid node i to the communication distance of node j; C represents the light velocity; M represents the nodal point number of communication path process; t _vrepresent the call duration time of single node; Δ t represents randomized jitter time delay; T _ijmthe set-point of representing fault information delay; B representing fault information gathering amount; P _irepresent communication reliability degree; P _xirepresent the reliability of communication device; P _yirepresent the reliability of circuit between communication device; P _imrepresent the set-point of communication reliability; I=1,2......n, j=1,2......n, U represent microgrid busbar voltage;

Step 6.2, employing breadth first search method, and provide the initial solution of breadth first search, namely initial microgrid current protection zoning, this initial solution can be produced by random device or be produced by existing heuristic;

Step 6.3, with the above-mentioned constraints provided for boundary, utilize breadth first search method from initial solution, search for the optimal solution of above-mentioned target function;

Step 6.4, the locally optimal solution searched is put into taboo list; taboo list all upgrades in each iteration; this locally optimal solution is avoided during search next time; and other space is searched for; until acquisition globally optimal solution, till namely meeting the optimum microgrid current protection zoning of above-mentioned target function and constraints.