CN109888748A

CN109888748A - One kind being based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity

Info

Publication number: CN109888748A
Application number: CN201910188386.6A
Authority: CN
Inventors: 郭亮; 安义; 徐在德; 邓才波; 李升健
Original assignee: Nanchang Ke Chen Electric Power Test Research Co Ltd; State Grid Corp of China SGCC; Electric Power Research Institute of State Grid Jiangxi Electric Power Co Ltd
Current assignee: Nanchang Ke Chen Electric Power Test Research Co Ltd; State Grid Corp of China SGCC; Electric Power Research Institute of State Grid Jiangxi Electric Power Co Ltd
Priority date: 2019-03-13
Filing date: 2019-03-13
Publication date: 2019-06-14
Anticipated expiration: 2039-03-13
Also published as: CN109888748B

Abstract

One kind being based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity; there was only backbone for distribution line; distribution line has backbone and branch line; and distribution line has three kinds of backbone, branch line and secondary branch line situations, establishes the expection fault outage distribution transforming total capacity calculation formula of consideration line fault probability corresponding to three-level protective allocation plan respectively.By calculating the fault outage capacity of distribution transform of limited kind of relaying configuration scheme, specific calculation process is provided respectively；The minimum corresponding switch setting position of distribution line power failure capacity and quantity are eventually found, thus the three-level protective allocation plan optimized.Attached drawing is second and third grade of backbone switch distance and distribution transforming distribution.The method of the present invention, solve the problems, such as distribution line three-level protective optimization collocation principle, algorithm and in terms of exist, this method can realize computer software programming, for distribution line three-level protective configuration automatic quick calculating provide possibility.

Description

One kind being based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity

Technical field

The present invention relates to one kind to be based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, belongs to power distribution network Protection technique field.

Background technique

For the 10kV distribution line of part 110kV substation power supply, line conductor is longer, the biggish feelings of line impedance Under condition, can configure the cooperation that three-level protective realizes the superior and the subordinate's protection: substation's outlet switch is protected as the first order of route, Protect the place setting in the big Mr. Yu's limit value of impedance, on the basis of second level protective position determines, third level protection in the second level According to the impedance magnitude at the protection of the second level, impedance is greater than the place setting of another limit value on rear side of the protection of the second level.Second and third Grade protection by route on-pole switch or looped network cabinet switch serve as.The route of three-level protective is configured, third level protection rear side Only the line failure between third level protection, only tripping pair are protected in the corresponding third level switch of tripping, the second level to failure The second level answered switchs, and the line fault between only first and second grade protection is just tripped by outlet switch, realizes failure (especially Be rear side failure) subregion isolation, reduce fault outage range.

Since distribution line generally has branch and time branch line, according to its branched structure feature, the protection of second and third grade Can have multiple, therefore, if the impedance of certain position is equal to desired impedance limit value, any position on rear side of the position is settable Second level switch, the second level position of the switch is different, and corresponding definite value is also different；For the position of each second level protection setting It sets, may also set up third level switch in any position that impedance value is greater than the rear side at third level protection impedance limit value.Therefore from Theoretically, the scheme of three-level protective configuration has infinite a variety of

Summary of the invention

The object of the present invention is to which the invention proposes one kind to be based in order to obtain the three-level protective allocation plan of optimization The smallest distribution line three-level protective Optimal Configuration Method of power failure capacity.

The technical solution that the present invention realizes is as follows, and one kind is matched based on the smallest distribution line three-level protective optimization of power failure capacity Method is set, the method only has backbone for distribution line, and distribution line has backbone and branch line and distribution line to have Three kinds of backbone, branch line and secondary branch line situations are based on capacity of distribution transform and location information, establish three-level protective allocation plan respectively The expection fault outage distribution transforming total capacity calculation formula of corresponding consideration line fault probability, it is contemplated that power failure capacity of distribution transform depends on In the distribution transforming position the characteristics of, by calculating the fault outage capacity of distribution transform of limited kind of relaying configuration scheme, and provide respectively specific Calculation process, eventually find power failure capacity minimum corresponding switch and position and quantity be set, thus the three-level optimized Relaying configuration scheme.

The distribution line only has the expection fault outage distribution transforming total capacity Q of backbone are as follows:

In formula, λ_ZFor backbone unit length probability of malfunction；L_ZFor distribution line trunk line length；L_K2ZFor backbone second The grade position of the switch and backbone beginning distance；L_K3ZFor the backbone third level position of the switch and backbone beginning distance；S_jFor jth The capacity of a distribution transforming；l_jDistance of the position away from backbone beginning is connect by j-th of distribution transforming；For distribution transformings all on distribution line Total capacity；It switchs for the backbone second level to the distribution transforming total capacity between backbone end；For backbone third Grade is switched to the distribution transforming total capacity between backbone end；

Distribution line is divided into three sections by the second level, three step switch, and all distribution transforming total capacities are equal to each section of line on distribution line The sum of connect distribution transforming in road, that is,

In formula,For distribution transforming total capacities all on distribution line；For backbone beginning to the backbone second level Distribution transforming total capacity between switch；It is switched for the backbone second level total to the distribution transforming between backbone third level switch Capacity；It switchs for the backbone third level to the distribution transforming total capacity between backbone end；Therefore Q formula can convert are as follows:

The distribution line only has the selection algorithm process of the expection fault outage distribution transforming total capacity of backbone as follows:

(1) the minimum impedance Z under the big mode at the switch setting of the second level is acquired_2minAnd corresponding minimum range L_K2Zmin, And the minimum impedance Z under the big mode at third level switch setting_3minAnd corresponding minimum range L_K3Zmin；

(2) judge L_K3ZminWhether in length range (0,0.8L_Z) within, judgment method is with L_K3ZminIt is upper with the range Limit value 0.8L_ZCompare, if L_K3Zmin> 0.8L_Z, illustrate that the route cannot configure three-level protective, into other flow processings；If L_K3Zmin≤0.8L_Z, illustrate that the route can configure three-level protective；

(3) second level switch rear side distribution transforming number j=1, third level switch rear side distribution transforming number k=1 are enabled；

(4) L is enabled₂=L_K2Zmin, L₃=L_K3Zmin；

(5) judge L₃Whether in length range (0,0.8L_Z) within, if L₃> 0.8L_Z, illustrate that the traversal second level is completed Switch is fixed to be located at L₂When third level switch all possible distribution transforming positions the case where, at this point, entering step (8) changes the second level Switch fixed position；If L₃≤0.8L_Z, illustrate that third level switch is located at L₃Three-level protective can be configured, this seasonal backbone the Secondary switch position and backbone beginning distance are L₂, i.e. L_K2Z=L₂, the third level position of the switch and backbone beginning distance are L₃, That is L_K3Z=L₃；

(6) L is calculated according to Q formula_K2Z、L_K3ZCorresponding expected fault outage distribution transforming total capacity Q (L_K2Z,L_K3Z)；If Q_bestFor Initial value or Q (L_K2Z,L_K3Z) < Q_best, then by minimum expected fault outage distribution transforming total capacity Q_bestIt is assigned a value of Q (L_K2Z,L_K3Z), it is right The second level switch answered optimizes position (L_K2Zbest,L_K3Zbest) it is assigned a value of (L_K2Z,L_K3Z)；

(7) the fixed second level position of the switch is set to L_K2ZPlace, finds L_K3ZJ-th of distribution transforming of rear side, enables intermediate quantity L₃Deng In distance l of the distribution transforming position away from backbone beginning_j, i.e. L₃=l_j, while count number j adds 1, enters back into step (5), circulation time Go through all qualified distribution transforming positions；

(8) second level position of the switch is changed, L is found_K2ZK-th of distribution transforming of rear side updates the second level and switchs minimum range L_K2ZminDistance l for the distribution transforming position away from backbone beginning_kEven L_K2Zmin=l_k, judge L_K2ZminWhether length range (0, 0.8L_Z) within, if L_K2Zmin> 0.8L_Z, illustrate that all traversals are completed, enter step the knot that (9) output final optimization pass calculates Fruit；If L_K2Zmin≤0.8L_Z, illustrate that route protection is configured with the possibility advanced optimized, recalculate to obtain third level switch most Small distance L_K3Zmin, judge L_K3ZminWhether in length range (0,0.8L_Z) within, if L_K3Zmin> 0.8L_Z, illustrate that three-level protective is matched Set it is all traversal be completed, enter step (9) output final optimization pass calculate as a result, if L_K3Zmin≤0.8L_Z, illustrate in the presence of not The case where calculating, while count number k adds 1, count number j is assigned a value of 1 again, enters back into step (4), loops through and calculates；

(9) pass through the above workflow management, finally obtain minimum expected fault outage distribution transforming total capacity Q_bestAnd its it is corresponding Second level switch optimizes position (L_K2Zbest,L_K3Zbest), export calculated result.

The distribution line has the expection fault outage distribution transforming total capacity Q (L of backbone and branch line_K2Fi,L_K3Fi,L_K2Zi, L_K3Z) it is as follows:

In formula,For the front end probability power failure capacity of all distribution transformings of whole distribution line, its calculation formula is

Wherein, S_AlwaysFor all of whole distribution line The sum of capacity of distribution transform；L_FiFor the length of each branch line；λ_FiFor each branch line unit length probability of malfunction；L_K2FiFor K_2FiPosition with Place branch line beginning distance, K_2FiFor the second level switch on certain branch line；Other each parameter meanings are as previously described；

For second level switch fault probability power failure capacity of distribution transform, its calculation formula is:

Wherein, S_ZBIt switchs for the backbone second level to the sum of all capacity of distribution transform between end；S_m3For third class branch The sum of all capacity of distribution transform on line；S_m42For the sum of all capacity of distribution transform on the 2nd kind of branch line of the 4th class；S_m43For the 4th class the 3rd The sum of all capacity of distribution transform on kind branch line；S_FiBFor the i branch line second level switch to all capacity of distribution transform between end it With；Other each parameter meanings are as previously described；

For third level switch fault probability power failure capacity of distribution transform, its calculation formula is:

Wherein, S_ZCIt switchs for the backbone third level to the sum of all capacity of distribution transform between end；S_m43For the 4th class the 3rd The sum of all capacity of distribution transform on kind branch line；S_FiCFor the i branch line third level switch to all capacity of distribution transform between end it With other each parameter meanings are as previously described.

When the distribution line has backbone and branch line, it is contemplated that the selection algorithm process of fault outage distribution transforming total capacity is such as Under:

(1) line information is obtained, and calculates the slave beginning of backbone, the corresponding effective end of branch line according to line information To end 0.8l_mImpedance ranges (Z_mi0, Z_mi)；Acquire the minimum impedance Z at the switch setting of the second level_2min；Third level switch is set Set the minimum impedance Z at place_3min；

(2) it judges whether there is certain impedance ranges and meets Z_3min∈(Z_mi0,Z_mi), if it does not exist, illustrate that the route cannot match Three-level protective is set, into other flow processings；If it exists, illustrate that the route can configure three-level protective, determination can be set three The conducting wire of grade switch；Calculate the length L at each three step switch setting positional distance backbone beginning_K3Zmin、L_K3Fimin, judge simultaneously Z_2min∈(Z_mi0,Z_mi), calculate the length L at each two-stage switch setting positional distance backbone beginning_K2Zmin、L_K2Fimin；

(3) it enables

(4) judgeEach element whether exceed corresponding line maximum magnitude 0.8l_miIfIn there is no being less than 0.8l_miElement, illustrate to be completed the switch fixation of the traversal second level and be located atWhen third level switch in all possible distribution transforming positions The case where；At this point, entering step (7), the fixed position of second level switch is changed；IfIt is middle to exist less than 0.8l_miElement, say Bright third level switch is located atThree-level protective can be configured, then is updatedIt deletes and is wherein greater than 0.8l_miElement, be retained less than 0.8l_miElement, this season each second level position of the switch takesEach element, i.e.,Each third level position of the switch takesEach element, i.e.,

(5) according to position of the switch predeterminated position, according to Q (L after classifying to each conducting wire_K2Fi,L_K3Fi,L_K2Zi,L_K3Z) formula It calculatesCorresponding expected fault outage distribution transforming total capacity Q (L_K2Fi,L_K3Fi,L_K2Zi,L_K3Z)；If Q_bestFor initial value or Q(L_K2Fi,L_K3Fi,L_K2Zi,L_K3Z) < Q_best, then by minimum expected fault outage distribution transforming total capacity Q_bestIt is assigned a value of Q (L_K2Fi, L_K3Fi,L_K2Zi,L_K3Z), corresponding second level switch optimizes positionIt is assigned a value of

(6) the fixed second level position of the switch is set toPlace, findsThe 1st after the corresponding each place on line of each element The impedance for calculating each distribution transforming is asked in distribution transforming；Minimum impedance therein is taken, the positional distance backbone for calculating the corresponding each route of the impedance is sought The distance at beginning, is denoted asEnable intermediate quantityIt enters back into step (5), loops through all qualified distribution transforming positions；

(7) second level position of the switch is changed, is foundResistance after the corresponding each place on line of each element at the 1st distribution transforming It is anti-, take minimum impedance Z therein_P2, the distance for calculating the positional distance backbone beginning of the corresponding each route of the impedance is sought, is denoted asIt updates the second level and switchs minimum range L_K2Zmin、L_K2FiminForCorresponding element, judgementWhether length range (0, 0.8l_mi) within；IfAll elements are all larger than 0.8l_mi, illustrate that all traversals are completed, enter step (8) output final optimization pass The result of calculating；IfThere are elements to be less than 0.8l_mi, illustrate that route protection is configured with the possibility advanced optimized, at this time basis Impedance Z at the switch of the second level_P2It recalculates to obtain the corresponding minimum impedance Z of third level switch_P3, ask the calculation impedance corresponding The distance at the positional distance backbone beginning of each route, is denoted asIt updates the third level and switchs minimum range L_K3Zmin、L_K3FiminFor Corresponding element, judgementWhether in length range (0,0.8l_mi) within, ifAll elements are all larger than 0.8l_mi, illustrate variation After secondary switch position, it can not continue to configure third level protection, all traversals are completed, and enter step (8) output final optimization pass The result of calculating；IfThere are elements to be less than 0.8l_mi, illustrate that three-level protective can be configured after changing the second level position of the switch, It enters step (3) and loops through calculating；

(8) pass through the above workflow management, finally obtain minimum expected fault outage distribution transforming total capacity Q_bestAnd its it is corresponding Second level switch optimizes positionExport calculated result.

The distribution line has the expection fault outage distribution transforming total capacity Q of backbone, branch line and secondary branch line_fcIt is as follows:

In formula, N_CFor the sum of secondary branch line total quantity, it may be assumed thatWherein, N_iFor the secondary branch line on i-th of branch line Quantity；

For the front end probability power failure capacity of all distribution transformings of whole distribution line, its calculation formula is:

Wherein, S_AlwaysFor the sum of all capacity of distribution transform of whole distribution line, other each parameter meanings are as previously described；

For backbone second level switch fault probability power failure capacity of distribution transform, its calculation formula is:

Wherein, ∑ λ L_K3CZThe third level for all third class time branch lines being coupled on backbone switchs to the length at its beginning Degree and the product of probability of malfunction and；∑λL_b0For all the 2nd kind branch of the 4th class between second and third grade of switch of backbone The product of the length and probability of malfunction of line and；S_ZBIt switchs for the backbone second level to the sum of all capacity of distribution transform between end； S_mf3For the sum of all capacity of distribution transform on all third class branch lines；S_mf42For all distribution transformings on the 2nd kind of branch line of all 4th classes The sum of capacity；S_mf43For the sum of all capacity of distribution transform on the 3rd kind of branch line of all 4th classes；S_mc3ZIt is coupled on backbone to be all Third class time branch line on the sum of all capacity of distribution transform；S_b0For all the 4th classes between second and third grade of switch of backbone The sum of all capacity of distribution transform on 2nd kind branch line；S_c0For all distribution transformings on the 3rd kind branch line of all the 4th classes for being coupled to backbone The sum of capacity；Other each parameter meanings are as previously described；

For branch line second level switch fault probability power failure capacity of distribution transform, its calculation formula is:

Wherein, ∑ λ L_K3CFiFor all thirds being located at after numbering the first kind for being i or second class branch line second level switch The third level of class time branch line switch it is to the product of the length and probability of malfunction at its beginning and；∑λL_b1iIt is i for all numbers that are located at Second and third grade of switch of first kind branch line between the 2nd kind of the 4th class time branch line length and probability of malfunction product and；∑ λL_b2iFor the length of all the 2nd kind branch lines of the 4th class being located between second and third grade of switch of the second class branch line that number is i With the product of probability of malfunction and；S_FiBFor be connected to the second level of i-th of branch line switch to all capacity of distribution transform between end it With；S_mc3FiTo be connected to the sum of all capacity of distribution transform on the third class time branch line of i-th of branch line；S_b1iFor be connected to that number is i the The sum of all capacity of distribution transform on the 2nd kind branch line of the 4th class of a kind of branch line；S_b2iTo be connected to the second class branch that number is i The sum of all capacity of distribution transform on the 2nd kind branch line of the 4th class of line；Other each parameter meanings are as previously described；

For secondary branch line third level switch fault probability power failure capacity of distribution transform, its calculation formula is:

Wherein, S_CiCIt switchs for the third class time branch line third level of number i to end The sum of all capacity of distribution transform between end, other each parameter meanings are as previously described.

It is characterized in that, when the distribution line has backbone, branch line and secondary branch line, it is contemplated that fault outage distribution transforming is always held The selection algorithm process of amount is as follows:

(1) line information is obtained, and backbone, branch line and the corresponding effective end of secondary branch line are calculated according to line information Slave beginning to end 0.8l_mImpedance ranges (Z_mi0, Z_mi)；Acquire the minimum impedance Z at the switch setting of the second level_2min；Third Minimum impedance Z at grade switch setting_3min；

(2) it judges whether there is certain impedance ranges and meets Z_3min∈(Z_mi0,Z_mi)；If it does not exist, illustrate that the route cannot match Three-level protective is set, into other flow processings；If it exists, illustrate that the route can configure three-level protective, determination can be set three The conducting wire of grade switch；Calculate the length L at each three step switch setting positional distance backbone beginning_K3Zmin、L_K3Fimin、L_K3Cimin, together When judge Z_2min∈(Z_mi0,Z_mi)；Calculate the length L at each two-stage switch setting positional distance backbone beginning_K2Zmin、L_K2Fimin、 L_K2Cimin；

(3) it enables

(4) judgeEach element whether exceed corresponding line maximum magnitude 0.8l_mi；IfIn there is no being less than 0.8l_miElement, illustrate to be completed the switch fixation of the traversal second level and be located atWhen third level switch in all possible distribution transforming positions The case where；At this point, entering step (7) changes the fixed position of second level switch；IfIt is middle to exist less than 0.8l_miElement, say Bright third level switch is located atThree-level protective can be configured, then is updatedIt deletes and is wherein greater than 0.8l_miElement, be retained less than 0.8l_miElement, this season each second level position of the switch takesEach element, i.e.,Each third level position of the switch takes Each element, i.e.,

(5) according to position of the switch predeterminated position, according to Q after classifying to each conducting wire_fcFormula calculatesIt is corresponding It is expected that fault outage distribution transforming total capacity Q_fcIf Q_bestFor initial value or Q_fc< Q_best, then minimum expected fault outage distribution transforming is total Capacity Q_bestIt is assigned a value of Q_fc, corresponding second level switch optimization positionIt is assigned a value of

(6) the fixed second level position of the switch is set toPlace, findsThe 1st after the corresponding each place on line of each element Distribution transforming asks the impedance for calculating each distribution transforming, takes minimum impedance therein；Seek the positional distance backbone for calculating the corresponding each route of the impedance The distance at beginning, is denoted asEnable intermediate quantityIt enters back into step (4), loops through all qualified with displacement It sets；

(7) second level position of the switch is changed, is foundResistance after the corresponding each place on line of each element at the 1st distribution transforming It is anti-, take minimum impedance Z therein_P2, the distance for calculating the positional distance backbone beginning of the corresponding each route of the impedance is sought, is denoted asIt updates the second level and switchs minimum range L_K2Zmin、L_K2Fimin、L_K2CiminForCorresponding element, judgementWhether in length range (0,0.8l_mi) within, ifAll elements are all larger than 0.8l_mi, illustrate that all traversals are completed, it is final to enter step (8) output Optimize the result calculated；IfThere are elements to be less than 0.8l_mi, illustrate that route protection is configured with the possibility advanced optimized, at this time According to the impedance Z at the switch of the second level_P2It recalculates to obtain the corresponding minimum impedance Z of third level switch_P3, ask and calculate the impedance pair The distance at the positional distance backbone beginning for each route answered, is denoted asIt updates the third level and switchs minimum range L_K3Zmin、 L_K3Fimin、L_K3CiminForCorresponding element, judgementWhether in length range (0,0.8l_mi) within, ifAll elements are all larger than 0.8l_mi, illustrate after changing second level switch position, can not continue to configure third level protection, all traversals are completed, enter step (8) result that output final optimization pass calculates；IfThere are elements to be less than 0.8l_mi, illustrate after changing the second level position of the switch, it can To configure three-level protective, enters step (3) and loop through calculating；

(8) pass through above-mentioned workflow management, finally obtain minimum expected fault outage distribution transforming total capacity Q_bestAnd its it is corresponding Second level switch optimizes positionExport calculated result.

The invention has the advantages that the present invention is based on the smallest distribution line three-level protective of the power failure capacity sides of distributing rationally Method, solve the problems, such as distribution line three-level protective optimization collocation principle, algorithm and in terms of exist, the party Method can realize computer software programming, and the automatic quick calculating for the configuration of distribution line three-level protective provides possibility.

Detailed description of the invention

Fig. 1 is second and third grade of backbone switch distance and distribution transforming distribution schematic diagram；

Fig. 2 is that third level switch influences to be expected power failure capacity schematic diagram with distribution transforming relative position；

Fig. 3 is that second and third grade switch influences to be expected power failure capacity schematic diagram with distribution transforming relative position；

Fig. 4 is the computational algorithm flow chart that fault outage distribution transforming total capacity is expected when three-level protective configuration only has backbone；

Fig. 5 is way sort schematic diagram after the distribution line three-level protective setting containing branch line；

Fig. 6 is the selection algorithm flow chart of expected fault outage distribution transforming total capacity when having backbone and branch line；

Fig. 7 is way sort schematic diagram after the distribution line three-level protective setting containing secondary branch line；

Fig. 8 is the selection algorithm flow chart of expected fault outage distribution transforming total capacity when having backbone, branch line and secondary branch line.

Specific embodiment

The present embodiment one kind is based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, first according to three The principle of grade protection cooperation, in the minimum impedance or the most short of positional distance beginning is arranged for determining that second level switch is arranged at position After distance, the minimum impedance acquired at third level switch setting position or the most short distance that positional distance beginning is set can be calculated From, then expection power failure distribution transforming total capacity of the various protection schemes in fault treating procedure under different situations is calculated, it finds most The corresponding optimal water allocation scheme of small expection power failure distribution transforming total capacity.

The condition that second level switch setting position meets:

The impedance Z under big mode at the switch setting position of the second level₂Following relationship should be met:

Z₂≥1.5Z_{It is small}

In formula, Z_{It is small}For the system impedance under minimum mode at route beginning, that is, 10kV bus, the impedance for meeting above formula is Z₂ Position be exactly that the second level switchs the position that can be set.

The condition that third level switch setting position meets:

The impedance Z under big mode at third level switch setting position₃Following relationship should be met:

Z₃≥1.5Z_{2 is small}

In formula, Z_{2 is small}The system impedance at setting under minimum mode is switched for the second level, the impedance for meeting above formula is Z₃Position Set is exactly that the third level switchs the position that can be set.

It is expected that fault outage distribution transforming total capacity calculation formula and calculation process, are considered to implement by following three kinds of situations.

The first situation, distribution line only have backbone:

Establishing electric line trunk line length is L_Z, the probability that backbone breaks down is identical, and unit length probability of malfunction is λ_Z；For there was only the distribution line of backbone, second level switch is located on backbone and only one, and the third level switchs same position In on backbone and only one, if the backbone second level position of the switch and backbone beginning distance be L_K2Z, the backbone third level The position of the switch and backbone beginning distance are L_K3Z, the capacity of j-th of distribution transforming is S on backbone_j, as shown in Figure 1.

Then it is expected fault outage distribution transforming total capacity Q are as follows:

In formula, λ_ZFor backbone unit length probability of malfunction, L_ZFor distribution line trunk line length, L_K2ZFor backbone second The grade position of the switch and backbone beginning distance, L_K3ZFor the backbone third level position of the switch and backbone beginning distance；S_jFor jth The capacity of a distribution transforming, l_jDistance of the position away from backbone beginning is connect by j-th of distribution transforming；For distribution transformings all on distribution line Total capacity；It switchs for the backbone second level to the distribution transforming total capacity between backbone end；For backbone third Grade is switched to the distribution transforming total capacity between backbone end.

Distribution line is divided into three sections by the second level, three step switch, and all distribution transforming total capacities are equal to each section of line on distribution line The sum of connect distribution transforming in road, i.e.,

In formula,For distribution transforming total capacities all on distribution line,For backbone beginning to the backbone second level Distribution transforming total capacity between switch,It is switched for the backbone second level total to the distribution transforming between backbone third level switch Capacity,It switchs for the backbone third level to the distribution transforming total capacity between backbone end.Therefore formula (1) can convert Are as follows:

By taking the distribution line of Fig. 1 as an example, each distribution transforming is distributed among three section leads, relevant to capacity of distribution transform in formula (2) Each amount is respectively as follows:

From formula (2) as can be seen that the distribution transforming for three sections of routes that second and third grade of switch is divided on the backbone be distributed it is constant In the case of, it is contemplated that the size of fault outage distribution transforming total capacity Q is decided by second and third grade of position of the switch of backbone and backbone beginning Distance L_K2Z、L_K3Z, it is clear that in the case where distribution transforming distribution and the constant second level position of the switch, L_K3ZIt is minimized, can make to be expected Fault outage distribution transforming total capacity Q is minimum；In the case where distribution transforming distribution situation is constant, second and third grade of position of the switch and backbone Beginning distance L_K2Z、L_K3ZReach minimum simultaneously, expected fault outage distribution transforming total capacity Q can be made minimum.

In the case of distribution transforming distribution and the constant second level position of the switch, it is explained with reference to Fig. 2.

Such as Fig. 2, the second level position of the switch is fixed, the third level switch position can between distribution transforming j-1 and j any position, Obviously, it is located nearest at the position of previous distribution transforming j-1 when the third level switchs, corresponding L_K3ZMinimum, at this time corresponding expection Fault outage distribution transforming total capacity Q_j-1It is minimum.

For distribution transforming be distributed constant and second and third grade of position of the switch it is variable in the case of, be explained with reference to Fig. 3.

As shown in Figure 32, it is assumed that the second level switch can between distribution transforming position k-1 and k any position, the third level switch Position can between distribution transforming j-1 and j any position, it is clear that when the second level, switch is located nearest to the position of distribution transforming k-1, simultaneously Third level switch is when being located nearest to the position of distribution transforming j-1, to being contemplated that fault outage distribution transforming total capacity Q₁It is minimum.

Simultaneously as minimum impedance at the third level position of the switch is by the impedance influences at the switch of the second level, and conducting wire The impedance magnitude of position is decided by the distance at this apart from beginning, and impedance is bigger, and corresponding distance is bigger；Therefore L_K3ZPosition By L_K2ZLimitation, each L_K2ZA corresponding L_K3ZMinimum value, therefore, the second level switch determine after, should be first according to formula (1) it acquires third level switch and is set to and meet corresponding expected fault outage distribution transforming near each distribution transforming position that distance limitation requires Total capacity is compared and obtains the corresponding minimum expected fault outage distribution transforming total capacity in the second level position of the switch；When the second level is opened When off position changes, then the second level should be switched and be set in turn near each distribution transforming position that satisfaction distance limitation requires, continued According to formula (1) acquire the third level switch be set to meet distance limitation require each distribution transforming position near corresponding expected failure stop Electric distribution transforming total capacity is compared and obtains each corresponding minimum expected fault outage distribution transforming total capacity；Until exhaustive all possible Position of the switch facilities finally obtain the minimum expected fault outage distribution transforming total capacity under all situations.

To sum up, when distribution line only has backbone, in the optional range of second and third grade of position of the switch, have infinite more Kind of position of the switch facilities, wherein only needing to ask calculation according to formula (1) and when more each position of the switch is located near distribution transforming position Various situations expection fault outage distribution transforming total capacity Q, find wherein the smallest value, corresponding second and third grade switch of the value Position and corresponding relaying configuration scheme are exactly distribution line three-level protective configuration optimal case.

On the basis of above, it is contemplated that the selection algorithm process of fault outage distribution transforming total capacity is as described below:

1) the minimum impedance Z under the big mode at the switch setting of the second level is acquired_2minAnd corresponding minimum range L_K2Zmin, And the minimum impedance Z under the big mode at third level switch setting_3minAnd corresponding minimum range L_K3Zmin；

2) judge L_K3ZminWhether in length range (0,0.8L_Z) within, judgment method is with L_K3ZminIt is upper with the range Limit value 0.8L_ZCompare, if L_K3Zmin> 0.8L_Z, illustrate that the route cannot configure three-level protective, into other flow processings；If L_K3Zmin≤0.8L_Z, illustrate that the route can configure three-level protective；

3) second level switch rear side distribution transforming number j=1, third level switch rear side distribution transforming number k=1 are enabled；

4) L is enabled₂=L_K2Zmin, L₃=L_K3Zmin；

5) judge L₃Whether in length range (0,0.8L_Z) within, if L₃> 0.8L_Z, illustrate that the traversal second level, which is completed, opens It closes fixed positioned at L₂When third level switch all possible distribution transforming positions the case where, opened at this point, entering step and 8) changing the second level Close fixed position；If L₃≤0.8L_Z, illustrate that third level switch is located at L₃Three-level protective can be configured, this seasonal backbone second The grade position of the switch and backbone beginning distance are L₂, i.e. L_K2Z=L₂, the third level position of the switch and backbone beginning distance are L₃, i.e., L_K3Z=L₃；

6) L is calculated according to formula (1)_K2Z、L_K3ZCorresponding expected fault outage distribution transforming total capacity Q (L_K2Z,L_K3Z), if Q_bestFor Initial value or Q (L_K2Z,L_K3Z) < Q_best, then by minimum expected fault outage distribution transforming total capacity Q_bestIt is assigned a value of Q (L_K2Z,L_K3Z), it is right The second level switch answered optimizes position (L_K2Zbest,L_K3Zbest) it is assigned a value of (L_K2Z,L_K3Z)；

7) the fixed second level position of the switch is set to L_K2ZPlace, finds L_K3ZJ-th of distribution transforming of rear side, enables intermediate quantity L₃It is equal to Distance l of the distribution transforming position away from backbone beginning_j, i.e. L₃=l_j, while count number j adds 1, enters back into step 5), loops through institute There is qualified distribution transforming position；

8) second level position of the switch is changed, L is found_K2ZK-th of distribution transforming of rear side updates the second level and switchs minimum range L_K2ZminDistance l for the distribution transforming position away from backbone beginning_kEven L_K2Zmin=l_k, judge L_K2ZminWhether length range (0, 0.8L_Z) within, if L_K2Zmin> 0.8L_Z, illustrate that all traversals are completed, enter step the result that 9) output final optimization pass calculates； If L_K2Zmin≤0.8L_Z, illustrate that route protection is configured with the possibility advanced optimized, recalculate to obtain third level switch minimum Distance L_K3Zmin, judge L_K3ZminWhether in length range (0,0.8L_Z) within, if L_K3Zmin> 0.8L_Z, illustrate that three-level protective configures All traversals are completed, enter step 9) output final optimization pass calculate as a result, if L_K3Zmin≤0.8L_Z, illustrate that presence does not calculate The case where, while count number k adds 1, count number j is assigned a value of 1 again, enters back into step 4), loops through and calculates；

9) pass through the above workflow management, finally obtain minimum expected fault outage distribution transforming total capacity Q_bestAnd its corresponding Secondary switch optimizes position (L_K2Zbest,L_K3Zbest), export calculated result.

Computational algorithm process such as Fig. 4 institute of fault outage distribution transforming total capacity is expected in three-level protective configuration when there was only backbone Show.

Second situation, distribution line have backbone and branch line:

For there is the distribution line of backbone and branch line, second and third grade of switch may appear in backbone simultaneously and divide On branch line, i.e., the number of second and third grade switch is likely larger than 1.Establishing electric line trunk line length is L_Z, unit length failure Probability is λ_Z；Branch line on backbone has M (M >=0) item, and each branch line is connected to the position of backbone away from backbone beginning length Respectively l_F1、l_F2、…、l_FM, the length of each branch line is respectively L_F1、L_F2、…、L_FM, each branch line unit length probability of malfunction Respectively λ_F1、λ_F2、…、λ_FM；The distribution transforming quantity that distribution line is mounted is R, and jth (0≤j≤R) a capacity is S_j, position Setting apart from place backbone or branch line beginning is l_j。

According to distribution line information, a total of 1 backbone of route, M branch line, the corresponding end of every conducting wire, Therefore M+1 end is shared.Each end is numbered, the length for remembering each end to backbone beginning is respectively l_mi(1≤i≤M + 1), before determining second and third grade of position of the switch, to the connecting point positions of all branch lines and corresponding l_mi0.8 times compared Compared with if the distance at contact to backbone beginning is greater than 0.8l_mi, then the branch line and backbone share an end, referred to as effectively End.

On this basis, to backbone, corresponding end number is 1, calculates beginning to 0.8l_m1Between impedance variations Range is denoted as (Z_m10, Z_m1)；To certain branch line, remembers that its corresponding end number is i, calculate the branch line beginning to 0.8l_miIt Between impedance variations range (Z_mi0, Z_mi).It is Z that establishing electric line, which switchs the impedance at setting by the second level being calculated,₂, Judge Z₂Whether within each impedance ranges, for Z₂End in each range then shows on the corresponding conducting wire in the end Second level switch can be set.If the second level switch on backbone is denoted as K_2Z, K_2ZPosition and backbone beginning distance are L_K2Z, If also there is second level switch on certain branch line, it is denoted as K_2Fi, i is count parameter, K_2FiPosition is with place branch line beginning distance L_K2Fi.It is Z that establishing electric line, which switchs the impedance at setting by the third level being calculated,₃If Z₃In certain impedance ranges it It is interior, then show that third level switch can be set on the corresponding conducting wire in the end.If the third level switch on backbone is denoted as K_3Z, K_3ZPosition and backbone beginning distance are L_K3ZIf also there is third level switch on certain branch line, it is denoted as K_3Fi, i is count parameter, K_3FiPosition and place branch line beginning distance are L_K3Fi。

According to diversity switch whether is arranged on each route and the number of diversity switch is arranged, the conducting wire of whole route is divided into Four classes:

(1) there are the second level and third level switch on route simultaneously

(2) there was only second level switch on route；

(3) there was only third level switch on route；

(4) it is not switched on route, this kind of only branch line can be subdivided into before being entirely located in second level switch, all Between second and third grade switch, it is entirely located in third level switch equal 3 microspecies later；

Way sort after distribution line three-level protective setting containing branch line, as shown in Figure 5.

Remember that branch line quantity is m in first kind conducting wire₁, branch line quantity is m in the second class conducting wire₂, in third-class conductor point Branch line quantity is m₃, the 4th class conducting wire the 1st, 2,3 kind of branch line quantity m₄₁、m₄₂、m₄₃, branch line number is according to m₁, m₂, m₃, m₄₁、 m₄₂、m₄₃Sequence it is cumulative, i.e. M=m₁+m₂+m₃+m₄₁+m₄₂+m₄₃, then it is expected fault outage distribution transforming total capacity Q (L_K2Fi,L_K3Fi, L_K2Zi,L_K3Z) are as follows:

In formula,For the front end probability power failure capacity of all distribution transformings of whole distribution line, its calculation formula is:

Wherein, S_AlwaysFor all of whole distribution line The sum of capacity of distribution transform, other each parameter meanings are as previously described；

Wherein, S_ZBIt switchs for the backbone second level to the sum of all capacity of distribution transform between end, S_m3For third class branch The sum of all capacity of distribution transform, S on line_m42For the sum of all capacity of distribution transform on the 2nd kind of branch line of the 4th class, S_m43For the 4th class the 3rd The sum of all capacity of distribution transform, S on kind branch line_FiBFor the i branch line second level switch to all capacity of distribution transform between end it With other each parameter meanings are as previously described；

Wherein, S_ZCIt switchs for the backbone third level to the sum of all capacity of distribution transform between end, S_m43For the 3rd kind of branch line of the 4th class The sum of upper all capacity of distribution transform, S_FiCIt switchs for the i branch line third level to the sum of all capacity of distribution transform between end, other are each Parameter meaning is as previously described.

When the distribution line of configurable three-level protective has backbone and branch line, in the optional of second and third grade of position of the switch In range, there are infinite a variety of position of the switch facilities, wherein each when only needing respectively to switch near distribution transforming position The expection fault outage distribution transforming total capacity Q of kind situation, finds wherein the smallest value, corresponding second and third grade of position of the switch of the value And corresponding relaying configuration scheme is exactly relaying configuration optimal case.

When distribution line has backbone and branch line, it is contemplated that the selection algorithm process of fault outage distribution transforming total capacity is as follows It is described:

1) line information is obtained, and calculates the slave beginning of backbone, the corresponding effective end of branch line according to line information To end 0.8l_mImpedance ranges (Z_mi0, Z_mi)；Acquire the minimum impedance Z at the switch setting of the second level_2min；Third level switch is set Set the minimum impedance Z at place_3min。

2) it judges whether there is certain impedance ranges and meets Z_3min∈(Z_mi0,Z_mi), if it does not exist, illustrate that the route cannot match Three-level protective is set, into other flow processings；If it exists, illustrate that the route can configure three-level protective, determination can be set three The conducting wire of grade switch calculates the length L at each three step switch setting positional distance backbone beginning_K3Zmin、L_K3Fimin, judge simultaneously Z_2min∈(Z_mi0,Z_mi), calculate the length L at each two-stage switch setting positional distance backbone beginning_K2Zmin、L_K2Fimin。

3) it enables

4) judgeEach element whether exceed corresponding line maximum magnitude 0.8l_miIfIn there is no be less than 0.8l_mi Element, illustrate to be completed the switch fixation of the traversal second level and be located atWhen third level switch all possible distribution transforming positions feelings 7) condition changes the fixed position of second level switch at this point, entering step；IfIt is middle to exist less than 0.8l_miElement, illustrate third Grade switch is located atThree-level protective can be configured, then is updatedIt deletes and is wherein greater than 0.8l_miElement, be retained less than 0.8l_mi Element, this season each second level position of the switch takesEach element, i.e.,Each third level position of the switch takesIt is each Element, i.e.,

5) it according to position of the switch predeterminated position, is calculated after classifying to each conducting wire according to formula (3)It is corresponding It is expected that fault outage distribution transforming total capacity Q (L_K2Fi,L_K3Fi,L_K2Zi,L_K3Z), if Q_bestFor initial value or Q (L_K2Fi,L_K3Fi,L_K2Zi, L_K3Z) < Q_best, then by minimum expected fault outage distribution transforming total capacity Q_bestIt is assigned a value of Q (L_K2Fi,L_K3Fi,L_K2Zi,L_K3Z), it is corresponding Second level switch optimizes positionIt is assigned a value of

6) the fixed second level position of the switch is set toPlace, findsThe 1st after the corresponding each place on line of each element Distribution transforming asks the impedance for calculating each distribution transforming, takes minimum impedance therein, seeks the positional distance backbone for calculating the corresponding each route of the impedance The distance at beginning, is denoted asEnable intermediate quantityStep 5) is entered back into, all qualified distribution transforming positions are looped through.

7) second level position of the switch is changed, is foundResistance after the corresponding each place on line of each element at the 1st distribution transforming It is anti-, take minimum impedance Z therein_P2, the distance for calculating the positional distance backbone beginning of the corresponding each route of the impedance is sought, is denoted asIt updates the second level and switchs minimum range L_K2Zmin、L_K2FiminForCorresponding element, judgementWhether length range (0, 0.8l_mi) within, ifAll elements are all larger than 0.8l_mi, illustrate that all traversals are completed, enter step 8) output final optimization pass The result of calculating；IfThere are elements to be less than 0.8l_mi, illustrate that route protection is configured with the possibility advanced optimized, at this time basis Impedance Z at the switch of the second level_P2It recalculates to obtain the corresponding minimum impedance Z of third level switch_P3, ask the calculation impedance corresponding The distance at the positional distance backbone beginning of each route, is denoted asIt updates the third level and switchs minimum range L_K3Zmin、L_K3FiminFor Corresponding element, judgementWhether in length range (0,0.8l_mi) within, ifAll elements are all larger than 0.8l_mi, illustrate variation After secondary switch position, it can not continue to configure third level protection, all traversals are completed, and enter step 8) output final optimization pass meter Calculate as a result, ifThere are elements to be less than 0.8l_mi, illustrate that three-level protective can be configured after changing the second level position of the switch, into Enter step 3) and loops through calculating.

8) pass through the above workflow management, finally obtain minimum expected fault outage distribution transforming total capacity Q_bestAnd its corresponding Secondary switch optimizes positionExport calculated result.

The selection algorithm process that fault outage distribution transforming total capacity is expected when having backbone and branch line is as shown in Figure 6.

The third situation, distribution line have backbone, branch line and secondary branch line:

For there is a distribution line of backbone, branch line and secondary branch line, second level switch may appear in simultaneously backbone, On branch line or secondary branch line, i.e. the number of second level switch is likely larger than 1.

Establishing electric line trunk line length is L_Z, unit length probability of malfunction is λ_Z；Branch line on backbone have M (M >= 0) item, it is respectively l that each branch line, which is connected to the position of backbone away from backbone beginning length,_F1、l_F2、…、l_FM, the length of each branch line Degree is respectively L_F1、L_F2、…、L_FM, each branch line unit length probability of malfunction is respectively λ_F1、λ_F2、…、λ_FM；I-th (0≤i≤M) Secondary branch line quantity on a branch line is N_i(N_i>=0) item, each secondary branch line are connected to the position of i-th of branch line away from branch line beginning Length is respectively l_iC1、l_iC2、…、l_iCNi, each secondary leg length is respectively L_iC1、L_iC2、…、L_iCNi, each secondary branch line unit length event Hindering probability is respectively λ_iC1、λ_iC2、…、λ_iCNi.The distribution transforming quantity that establishing electric line is mounted is R, jth (0≤j≤R) a appearance Amount is S_j, positional distance backbone beginning is l_j.The distribution transforming quantity that distribution line is mounted is R, jth (0≤j≤R) a appearance Amount is S_j, backbone where positional distance or branch line beginning are l_j。

The two of distribution line containing backbone, branch line and secondary branch line and the distribution line containing backbone and branch line The optimal setting method and calculation formula of the second level switch of grade relaying configuration are roughly the same, except that for secondary branch line Processing.It since the line construction comprising secondary branch line is complex, is calculated if being carried out with length, can seem complicated and is difficult to hold Row, all comparison procedures are carried out using impedance at this time.

According to distribution line information, a total of 1 backbone of route, M branch line andItem time branch line, every is led Line corresponds to an end, therefore sharedA end.Each end is numbered, remembers that each end to backbone begins The length at end is respectively l_mi Before carrying out calculating, all branch lines and time branch line are connect Put position and corresponding l_mi0.8 times be compared, if contact to backbone beginning distance be greater than 0.8l_mi, then the branch line An end, referred to as effective end are shared with backbone or the secondary branch line and place branch line.

On this basis, to backbone, corresponding end number is 1, calculates beginning to 0.8l_m1Between impedance variations Range is denoted as (Z_m10, Z_m1)；To certain branch line, remembers that its corresponding end number is i, calculate the branch line beginning to 0.8l_miIt Between impedance variations range (Z_mi0, Z_mi)；To certain branch line, remembers that its corresponding end number is j, calculate at time branch line beginning extremely 0.8l_miBetween impedance variations range (Z_mj0, Z_mj).Establishing electric line switchs the resistance at setting by the second level being calculated Resist for Z₂, judge Z₂Whether within each impedance ranges, for Z₂End in each range then shows that the end is corresponding Conducting wire on can be set the second level switch.If the second level switch on backbone is denoted as K_2Z, K_2ZPosition and backbone beginning away from From for L_K2ZIf also there is second level switch on certain branch line, it is denoted as K_2Fi, i is count parameter, K_2FiPosition and place branch line begin End distance is L_K2FiIf also there is second level switch on certain branch line, it is denoted as K_2Cj, j is count parameter, K_2CjPosition and place branch Line beginning distance is L_K2Cj.It is Z that establishing electric line, which switchs the impedance at setting by the third level being calculated,₃If Z₃In certain Within impedance ranges, then show that third level switch can be set on the corresponding conducting wire in the end.If the third level on backbone opens Pass is denoted as K_3Z, K_3ZPosition and backbone beginning distance are L_K3ZIf also there is third level switch on certain branch line, it is denoted as K_3Fi, i is Count parameter, K_3FiPosition and place branch line beginning distance are L_K3FiIf also there is third level switch on certain branch line, it is denoted as K_3Cj, j is count parameter, K_3CjPosition and place branch line beginning distance are L_K3Cj。

According to diversity switch whether is arranged on each route and the number of diversity switch is arranged, the conducting wire of whole route is divided into Five classes:

(1) there are the second level and third level switch on route simultaneously；

(2) there was only second level switch on route；

(3) there was only third level switch on route；

(4) it is not switched on route, it is this kind of to have branch line and time branch line, it can be subdivided into and be entirely located in second level switch Before, it is entirely located between second and third grade of switch, is entirely located in third level switch equal 3 microspecies later；

Way sort after distribution line three-level protective setting containing secondary branch line, as shown in Figure 7.

Remember that branch line quantity is m in first kind conducting wire_f1, secondary branch line quantity is m_c1, branch line quantity is in the second class conducting wire m_f2, secondary branch line quantity is m_c2, branch line quantity is m in third-class conductor_f3, secondary branch line quantity is m_c3, the 4th class conducting wire the 1st, 2,3 Kind branch line quantity m_f41、m_f42、m_f43, secondary branch line quantity m_c41、m_c42、m_c43, branch line number is according to m_f1, m_f2, m_f3, m_f41、 m_f42、m_f43Sequence it is cumulative, i.e. M=m_f1+m_f2+m_f3+m_f41+m_f42+m_f43, secondary branch line number is according to m_c1, m_c2, m_c3, m_c41、m_c42、 m_c43Sequence it is cumulative, i.e.,

In m_c42In 2nd kind branch line of bar the 4th class conducting wire, it is possible to it is located between second and third grade of backbone switch, It is likely located between second and third grade of switch of first kind branch line, or switch rear side positioned at the second level of the second class branch line, if Secondary branch line quantity between second and third grade of switch of backbone is b0, is located at m_f1Second and third grade of first kind branch line is opened Quantity between pass is b1_i, it is located at m_f2The quantity of the second level switch rear side of item the second class branch line is b2_i, therefore

In m_c43In 3rd kind branch line of bar the 4th class conducting wire, it is possible to it is located at backbone third level switch rear side, it can also The third level that first kind branch line can be located at switchs rear side, it is also possible to and the third level positioned at third class branch line switchs rear side, if Wherein being located at the secondary branch line quantity on rear side of the backbone third level is c0, is located at m_f1The third level of first kind branch line switchs rear side Quantity be c1_i, it is located at m_f3The third level switch rear side quantity of third class branch line is c3_i；Therefore

Then it is expected fault outage distribution transforming total capacity Q_fcFor

In formula, N_CFor the sum of secondary branch line total quantity, i.e.,

Wherein, N_iFor the secondary branch line quantity on i-th of branch line；

Wherein, ∑ λ L_K3CZThe third level for all third class time branch lines being coupled on backbone switchs to the length at its beginning Degree and the product of probability of malfunction and, ∑ λ L_b0For all the 2nd kind branch of the 4th class between second and third grade of switch of backbone The product of the length and probability of malfunction of line and, S_ZBIt switchs for the backbone second level to the sum of all capacity of distribution transform between end, S_mf3For the sum of all capacity of distribution transform on all third class branch lines, S_mf42For all distribution transformings on the 2nd kind of branch line of all 4th classes The sum of capacity, S_mc3ZFor the sum of all capacity of distribution transform on all third class time branch lines being coupled on backbone, S_b0It is located to be all The sum of all capacity of distribution transform, S on the 2nd kind branch line of the 4th class between second and third grade of switch of backbone_c0Trunk is coupled to be all The sum of all capacity of distribution transform on the 3rd kind branch line of the 4th class of line；Other each parameter meanings are as previously described；

Wherein, ∑ λ L_K3CFiFor all thirds being located at after numbering the first kind for being i or second class branch line second level switch The third level of class time branch line switch it is to the product of the length and probability of malfunction at its beginning and, ∑ λ L_b1iIt is i for all numbers that are located at Second and third grade of switch of first kind branch line between the 2nd kind of the 4th class time branch line length and probability of malfunction product and, ∑ λL_b2iFor the length of all the 2nd kind branch lines of the 4th class being located between second and third grade of switch of the second class branch line that number is i With the product of probability of malfunction and, S_FiBFor be connected to the second level of i-th of branch line switch to all capacity of distribution transform between end it With S_mc3FiTo be connected to the sum of all capacity of distribution transform, S on the third class time branch line of i-th of branch line_b1iFor be connected to that number is i the The sum of all capacity of distribution transform, S on the 2nd kind branch line of the 4th class of a kind of branch line_b2iTo be connected to the second class branch that number is i The sum of all capacity of distribution transform on the 2nd kind branch line of the 4th class of line；Other each parameter meanings are as previously described；

For secondary branch line second level switch fault probability power failure capacity of distribution transform, its calculation formula is:

Wherein, S_CiBTo number be i the A kind of or the second class time branch line second level is switched to the sum of all capacity of distribution transform between end, for example preceding institute of other each parameter meanings It states；

For backbone third level switch fault probability power failure capacity of distribution transform, its calculation formula is:

Wherein, ∑ λ L_c0For all positions The product of the length and probability of malfunction of the 3rd kind of the 4th class time branch line after backbone three step switch and, S_ZCFor backbone third Grade is switched to the sum of all capacity of distribution transform between end, S_mf42For all capacity of distribution transform on the 3rd kind of branch line of all 4th classes The sum of, S_c0For the sum of all capacity of distribution transform on the 3rd kind branch line of all the 4th classes for being coupled to backbone；Other each parameter meanings are such as It is preceding described；

For branch line third level switch fault probability power failure capacity of distribution transform, its calculation formula is:

Wherein, ∑λL_c1iFor all the 3rd kind of the 4th class time branch lines being located at after the first kind branch line third level switch that number is i length with The sum of the product of probability of malfunction, ∑ λ L_c3iIt is located at the 4th class the 3rd after the third class branch line third level that number is i switchs to be all The product of the length and probability of malfunction of kind of time branch line and, S_FiBIt switchs to be connected to the second level of i-th of branch line between end The sum of all capacity of distribution transform, S_c1iTo be connected to all distribution transformings on the 3rd kind branch line of the 4th class for the first kind branch line that number is i The sum of capacity, S_c3iTo be connected to the sum of all capacity of distribution transform on the 3rd kind branch line of the 4th class for the second class branch line that number is i； Other each parameter meanings are as previously described；

Wherein, S_CiCFor number be i the third class time branch line third level switch to The sum of all capacity of distribution transform between end, other each parameter meanings are as previously described.

When distribution line has backbone, branch line and secondary branch line, in the optional range of second and third grade of position of the switch, have Infinite a variety of position of the switch facilities, wherein various situations when only needing respectively to switch near distribution transforming position is pre- Phase fault outage distribution transforming total capacity Q finds wherein the smallest value, corresponding second and third grade of position of the switch of the value and corresponding guarantor Protecting allocation plan is exactly relaying configuration optimal case.

When distribution line has backbone, branch line and secondary branch line, it is contemplated that the selection algorithm of fault outage distribution transforming total capacity Process is as follows:

1) line information is obtained, and backbone, branch line and the corresponding effective end of secondary branch line are calculated according to line information Slave beginning to end 0.8l_mImpedance ranges (Z_mi0, Z_mi)；Acquire the minimum impedance Z at the switch setting of the second level_2min；Third Minimum impedance Z at grade switch setting_3min。

2) it judges whether there is certain impedance ranges and meets Z_3min∈(Z_mi0,Z_mi), if it does not exist, illustrate that the route cannot match Three-level protective is set, into other flow processings；If it exists, illustrate that the route can configure three-level protective, determination can be set three The conducting wire of grade switch calculates the length L at each three step switch setting positional distance backbone beginning_K3Zmin、L_K3Fimin、L_K3Cimin, together When judge Z_2min∈(Z_mi0,Z_mi), calculate the length L at each two-stage switch setting positional distance backbone beginning_K2Zmin、L_K2Fimin、 L_K2Cimin。

3) it enables

4) judgeEach element whether exceed corresponding line maximum magnitude 0.8l_miIfIn there is no be less than 0.8l_mi Element, illustrate to be completed the switch fixation of the traversal second level and be located atWhen third level switch all possible distribution transforming positions feelings 7) condition changes the fixed position of second level switch at this point, entering step；IfIt is middle to exist less than 0.8l_miElement, illustrate third Grade switch is located atThree-level protective can be configured, then is updatedIt deletes and is wherein greater than 0.8l_miElement, be retained less than 0.8l_mi's Element, this season each second level position of the switch takeEach element, i.e.,Each third level position of the switch takesEach member Element, i.e.,

5) it according to position of the switch predeterminated position, is calculated after classifying to each conducting wire according to formula (4)It is corresponding It is expected that fault outage distribution transforming total capacity Q_fcIf Q_bestFor initial value or Q_fc< Q_best, then minimum expected fault outage distribution transforming is total Capacity Q_bestIt is assigned a value of Q_fc, corresponding second level switch optimization positionIt is assigned a value of

6) the fixed second level position of the switch is set toPlace, findsThe 1st after the corresponding each place on line of each element Distribution transforming asks the impedance for calculating each distribution transforming, takes minimum impedance therein, seeks the positional distance backbone for calculating the corresponding each route of the impedance The distance at beginning, is denoted asEnable intermediate quantityStep 4) is entered back into, all qualified distribution transforming positions are looped through.

7) second level position of the switch is changed, is foundResistance after the corresponding each place on line of each element at the 1st distribution transforming It is anti-, take minimum impedance Z therein_P2, the distance for calculating the positional distance backbone beginning of the corresponding each route of the impedance is sought, is denoted asIt updates the second level and switchs minimum range L_K2Zmin、L_K2Fimin、L_K2CiminForCorresponding element, judgementWhether in length range (0,0.8l_mi) within, ifAll elements are all larger than 0.8l_mi, illustrate that all traversals are completed, it is final excellent to enter step 8) output Change the result calculated；IfThere are elements to be less than 0.8l_mi, illustrate that route protection is configured with the possibility advanced optimized, at this time root According to the impedance Z at the switch of the second level_P2It recalculates to obtain the corresponding minimum impedance Z of third level switch_P3, ask the calculation impedance corresponding Each route positional distance backbone beginning distance, be denoted asIt updates the third level and switchs minimum range L_K3Zmin、L_K3Fimin、 L_K3CiminForCorresponding element, judgementWhether in length range (0,0.8l_mi) within, ifAll elements are all larger than 0.8l_mi, Illustrate after changing second level switch position, can not continue to configure third level protection, all traversals are completed, and enter step and 8) export Final optimization pass calculate as a result, ifThere are elements to be less than 0.8l_mi, illustrate to configure after changing the second level position of the switch Three-level protective enters step and 3) loops through calculating.

Selection algorithm process such as Fig. 8 institute of fault outage distribution transforming total capacity is expected when having backbone, branch line and secondary branch line Show.

Protection after being determined that second and third grade of switch setting optimizes position, according to protection cooperation principle to each switch Definite value carries out adaptive setting, as optimization collocation.

Claims

1. one kind is based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, which is characterized in that the method There was only backbone for distribution line, distribution line have backbone and branch line and distribution line have backbone, branch line and Three kinds of situations of secondary branch line；The expection fault outage for establishing consideration line fault probability corresponding to three-level protective allocation plan respectively is matched Become total capacity calculation formula；By calculating the fault outage capacity of distribution transform of limited kind of relaying configuration scheme, provide respectively specific Calculation process；The minimum corresponding switch setting position of distribution line power failure capacity and quantity are eventually found, to be optimized Three-level protective allocation plan.

2. one kind according to claim 1 is based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, It is characterized in that, the distribution line only has the expection fault outage distribution transforming total capacity Q of backbone are as follows:

In formula, λ_ZFor backbone unit length probability of malfunction；L_ZFor distribution line trunk line length；L_K2ZIt is opened for the backbone second level Off position and backbone beginning distance；L_K3ZFor the backbone third level position of the switch and backbone beginning distance；S_jMatch for j-th The capacity of change；l_jDistance of the position away from backbone beginning is connect by j-th of distribution transforming；Always hold for distribution transformings all on distribution line Amount；It switchs for the backbone second level to the distribution transforming total capacity between backbone end；For the backbone third level It switchs to the distribution transforming total capacity between backbone end；

Distribution line is divided into three sections by the second level, three step switch, and all distribution transforming total capacities are equal to each section of route institute on distribution line Connect the sum of distribution transforming, that is,

In formula,For distribution transforming total capacities all on distribution line；For backbone beginning to backbone second level switch Between distribution transforming total capacity；It switchs for the backbone second level to the distribution transforming between backbone third level switch and always holds Amount；It switchs for the backbone third level to the distribution transforming total capacity between backbone end；Therefore Q formula can convert are as follows:

3. one kind according to claim 2 is based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, It is characterized in that, the distribution line only has the selection algorithm process of the expection fault outage distribution transforming total capacity of backbone as follows:

(1) the minimum impedance Z under the big mode at the switch setting of the second level is acquired_2minAnd corresponding minimum range L_K2Zmin, and The third level switchs the minimum impedance Z under the big mode at setting_3minAnd corresponding minimum range L_K3Zmin；

(2) judge L_K3ZminWhether in length range (0,0.8L_Z) within, judgment method is with L_K3ZminWith the upper limit value of the range 0.8L_ZCompare, if L_K3Zmin> 0.8L_Z, illustrate that the route cannot configure three-level protective, into other flow processings；If L_K3Zmin≤ 0.8L_Z, illustrate that the route can configure three-level protective；

(4) L is enabled₂=L_K2Zmin, L₃=L_K3Zmin；

(5) judge L₃Whether in length range (0,0.8L_Z) within, if L₃> 0.8L_Z, illustrate that traversal second level switch is completed admittedly It is positioned at L₂When third level switch all possible distribution transforming positions the case where, at this point, entering step (8), to change second level switch solid Fixed position；If L₃≤0.8L_Z, illustrate that third level switch is located at L₃Three-level protective can be configured, this seasonal backbone second level is opened Off position and backbone beginning distance are L₂, i.e. L_K2Z=L₂, the third level position of the switch and backbone beginning distance are L₃, i.e. L_K3Z =L₃；

(6) L is calculated according to Q formula_K2Z、L_K3ZCorresponding expected fault outage distribution transforming total capacity Q (L_K2Z,L_K3Z)；If Q_bestFor initial value Or Q (L_K2Z,L_K3Z) < Q_best, then by minimum expected fault outage distribution transforming total capacity Q_bestIt is assigned a value of Q (L_K2Z,L_K3Z), corresponding Secondary switch optimizes position (L_K2Zbest,L_K3Zbest) it is assigned a value of (L_K2Z,L_K3Z)；

(7) the fixed second level position of the switch is set to L_K2ZPlace, finds L_K3ZJ-th of distribution transforming of rear side, enables intermediate quantity L₃Match equal to this The distance l away from backbone beginning is set in displacement_j, i.e. L₃=l_j, while count number j adds 1, enters back into step (5), loops through all Qualified distribution transforming position；

(8) second level position of the switch is changed, L is found_K2ZK-th of distribution transforming of rear side updates the second level and switchs minimum range L_K2Zmin Distance l for the distribution transforming position away from backbone beginning_kEven L_K2Zmin=l_k, judge L_K2ZminWhether length range (0, 0.8L_Z) within, if L_K2Zmin> 0.8L_Z, illustrate that all traversals are completed, enter step the knot that (9) output final optimization pass calculates Fruit；If L_K2Zmin≤0.8L_Z, illustrate that route protection is configured with the possibility advanced optimized, recalculate to obtain third level switch most Small distance L_K3Zmin, judge L_K3ZminWhether in length range (0,0.8L_Z) within, if L_K3Zmin> 0.8L_Z, illustrate that three-level protective is matched Set it is all traversal be completed, enter step (9) output final optimization pass calculate as a result, if L_K3Zmin≤0.8L_Z, illustrate in the presence of not The case where calculating, while count number k adds 1, count number j is assigned a value of 1 again, enters back into step (4), loops through and calculates；

(9) pass through the above workflow management, finally obtain minimum expected fault outage distribution transforming total capacity Q_bestAnd its corresponding second level Switch optimizes position (L_K2Zbest,L_K3Zbest), export calculated result.

4. one kind according to claim 1 is based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, It is characterized in that, the distribution line has the expection fault outage distribution transforming total capacity Q (L of backbone and branch line_K2Fi,L_K3Fi, L_K2Zi,L_K3Z) it is as follows:

Wherein, S_AlwaysFor all distribution transformings of whole distribution line The sum of capacity；L_FiFor the length of each branch line；λ_FiFor each branch line unit length probability of malfunction；L_K2FiFor K_2FiPosition and place Branch line beginning distance, K_2FiFor the second level switch on certain branch line；Other each parameter meanings are as previously described；

Wherein, S_ZBIt switchs for the backbone second level to the sum of all capacity of distribution transform between end；S_m3For on third class branch line The sum of all capacity of distribution transform；S_m42For the sum of all capacity of distribution transform on the 2nd kind of branch line of the 4th class；S_m43It is 3rd kind point of the 4th class The sum of all capacity of distribution transform on branch line；S_FiBIt switchs for the i branch line second level to the sum of all capacity of distribution transform between end；Its His each parameter meaning is as previously described；

Wherein, S_ZCIt switchs for the backbone third level to the sum of all capacity of distribution transform between end；S_m43It is 3rd kind point of the 4th class The sum of all capacity of distribution transform on branch line；S_FiCIt switchs for the i branch line third level to the sum of all capacity of distribution transform between end, His each parameter meaning is as previously described.

5. one kind according to claim 4 is based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, It is characterized in that, when the distribution line has backbone and branch line, it is contemplated that the selection algorithm stream of fault outage distribution transforming total capacity Journey is as follows:

(1) line information is obtained, and calculates slave beginning to the end of backbone, the corresponding effective end of branch line according to line information Hold 0.8l_mImpedance ranges (Z_mi0, Z_mi)；Acquire the minimum impedance Z at the switch setting of the second level_2min；The third level switchs at setting Minimum impedance Z_3min；

(2) it judges whether there is certain impedance ranges and meets Z_3min∈(Z_mi0,Z_mi), if it does not exist, illustrate that the route cannot configure three Grade protection, into other flow processings；If it exists, illustrate that the route can configure three-level protective, determine that three-level, which can be set, to be opened The conducting wire of pass；Calculate the length L at each three step switch setting positional distance backbone beginning_K3Zmin、L_K3Fimin, while judging Z_2min∈ (Z_mi0,Z_mi), calculate the length L at each two-stage switch setting positional distance backbone beginning_K2Zmin、L_K2Fimin；

(3) it enables

(4) judgeEach element whether exceed corresponding line maximum magnitude 0.8l_miIfIn there is no be less than 0.8l_mi's Element illustrates that the switch fixation of the traversal second level, which is completed, to be located atWhen third level switch all possible distribution transforming positions the case where； At this point, entering step (7), the fixed position of second level switch is changed；IfIt is middle to exist less than 0.8l_miElement, illustrate third Grade switch is located atThree-level protective can be configured, then is updatedIt deletes and is wherein greater than 0.8l_miElement, be retained less than 0.8l_mi Element, this season each second level position of the switch takesEach element, i.e.,Each third level position of the switch takesIt is each Element, i.e.,

(5) according to position of the switch predeterminated position, according to Q (L after classifying to each conducting wire_K2Fi,L_K3Fi,L_K2Zi,L_K3Z) formula calculatingCorresponding expected fault outage distribution transforming total capacity Q (L_K2Fi,L_K3Fi,L_K2Zi,L_K3Z)；If Q_bestFor initial value or Q (L_K2Fi,L_K3Fi,L_K2Zi,L_K3Z) < Q_best, then by minimum expected fault outage distribution transforming total capacity Q_bestIt is assigned a value of Q (L_K2Fi,L_K3Fi, L_K2Zi,L_K3Z), corresponding second level switch optimizes positionIt is assigned a value of

(6) the fixed second level position of the switch is set toPlace, findsMatch for the 1st after the corresponding each place on line of each element Become, asks the impedance for calculating each distribution transforming；Minimum impedance therein is taken, the positional distance backbone for calculating the corresponding each route of the impedance is asked to begin The distance at end, is denoted asEnable intermediate quantityIt enters back into step (5), loops through all qualified distribution transforming positions；

(7) second level position of the switch is changed, is foundImpedance after the corresponding each place on line of each element at the 1st distribution transforming, takes Minimum impedance Z therein_P2, the distance for calculating the positional distance backbone beginning of the corresponding each route of the impedance is sought, is denoted asIt updates The second level switchs minimum range L_K2Zmin、L_K2FiminForCorresponding element, judgementWhether in length range (0,0.8l_mi) within； IfAll elements are all larger than 0.8l_mi, illustrate that all traversals are completed, enter step the result that (8) output final optimization pass calculates； IfThere are elements to be less than 0.8l_mi, illustrate that route protection is configured with the possibility that advanced optimizes, at this time according to second level switch at Impedance Z_P2It recalculates to obtain the corresponding minimum impedance Z of third level switch_P3, ask the position for calculating the corresponding each route of the impedance Distance apart from backbone beginning, is denoted asIt updates the third level and switchs minimum range L_K3Zmin、L_K3FiminForCorresponding element is sentenced It is disconnectedWhether in length range (0,0.8l_mi) within, ifAll elements are all larger than 0.8l_mi, illustrate to change second level switch position Later, can not continue to configure third level protection, all traversals are completed, and enter step the result that (8) output final optimization pass calculates； IfThere are elements to be less than 0.8l_mi, illustrate to configure three-level protective after changing the second level position of the switch, enter step (3) It loops through and calculates；

(8) pass through the above workflow management, finally obtain minimum expected fault outage distribution transforming total capacity Q_bestAnd its corresponding second level Switch optimizes positionExport calculated result.

6. one kind according to claim 4 is based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, It is characterized in that, second and third grade switchs while appearing in backbone and branch when the distribution line has backbone and branch line On line, i.e., the number of second and third grade switch is likely larger than 1；

According to diversity switch whether is arranged on each route and the number of diversity switch is arranged, the conducting wire of whole route is divided into four Class:

(2) there was only second level switch on route；

(3) there was only third level switch on route；

(4) it is not switched on route, this kind of only branch line can be subdivided into before being entirely located in second level switch, be entirely located in Between second and third grade switch, it is entirely located in 3 microspecies after third level switch.

7. one kind according to claim 1 is based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, It is characterized in that, the distribution line has the expection fault outage distribution transforming total capacity Q of backbone, branch line and secondary branch line_fcIt is as follows:

In formula, N_CFor the sum of secondary branch line total quantity, it may be assumed thatWherein, N_iFor the secondary branch line number on i-th of branch line Amount；

Its In, S_AlwaysFor the sum of all capacity of distribution transform of whole distribution line, other each parameter meanings are as previously described；

Wherein, ∑ λ L_K3CZThe third level for all third class time branch lines being coupled on backbone switchs to the length at its beginning and event Hinder the sum of the product of probability；∑λL_b0For the length of all the 2nd kind branch lines of the 4th class between second and third grade of switch of backbone Degree and the product of probability of malfunction and；S_ZBIt switchs for the backbone second level to the sum of all capacity of distribution transform between end；S_mf3For institute There are the sum of all capacity of distribution transform on third class branch line；S_mf42For all capacity of distribution transform on the 2nd kind of branch line of all 4th classes it With；S_mf43For the sum of all capacity of distribution transform on the 3rd kind of branch line of all 4th classes；S_mc3ZFor all thirds being coupled on backbone The sum of all capacity of distribution transform on class time branch line；S_b0For all the 4th class the 2nd kind times between second and third grade of switch of backbone The sum of all capacity of distribution transform on branch line；S_c0For all capacity of distribution transform on the 3rd kind of all the 4th classes for being coupled to backbone time branch line it With；Other each parameter meanings are as previously described；

Wherein, ∑ λ L_K3CFiFor all third classes time being located at after numbering the first kind for being i or second class branch line second level switch The third level of branch line switch it is to the product of the length and probability of malfunction at its beginning and；∑λL_b1iFor all be located at that number is i the The product of the length and probability of malfunction of the 2nd kind of the 4th class time branch line between second and third grade of switch of a kind of branch line and；∑λL_b2i The length and event of the 2nd kind branch lines of the 4th class between second and third grade of switch of all the second class branch lines for being i positioned at number Hinder the sum of the product of probability；S_FiBIt switchs to be connected to the second level of i-th of branch line to the sum of all capacity of distribution transform between end； S_mc3FiTo be connected to the sum of all capacity of distribution transform on the third class time branch line of i-th of branch line；S_b1iIt is the first of i to be connected to number The sum of all capacity of distribution transform on the 2nd kind branch line of the 4th class of class branch line；S_b2iTo be connected to the second class branch line that number is i The 2nd kind of the 4th class time branch line on the sum of all capacity of distribution transform；Other each parameter meanings are as previously described；

Wherein, S_CiCFor number i the third class time branch line third level switch to end it Between the sum of all capacity of distribution transform, other each parameter meanings are as previously described.

8. one kind according to claim 7 is based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, It is characterized in that, when the distribution line has backbone, branch line and secondary branch line, it is contemplated that the selection of fault outage distribution transforming total capacity Algorithm flow is as follows:

(1) obtain line information, and according to line information calculate backbone, branch line and the corresponding effective end of secondary branch line from Beginning to end 0.8l_mImpedance ranges (Z_mi0, Z_mi)；Acquire the minimum impedance Z at the switch setting of the second level_2min；The third level opens Close the minimum impedance Z at setting_3min；

(2) it judges whether there is certain impedance ranges and meets Z_3min∈(Z_mi0,Z_mi)；If it does not exist, illustrate that the route cannot configure three Grade protection, into other flow processings；If it exists, illustrate that the route can configure three-level protective, determine that three-level, which can be set, to be opened The conducting wire of pass；Calculate the length L at each three step switch setting positional distance backbone beginning_K3Zmin、L_K3Fimin、L_K3Cimin, sentence simultaneously Disconnected Z_2min∈(Z_mi0,Z_mi)；Calculate the length L at each two-stage switch setting positional distance backbone beginning_K2Zmin、L_K2Fimin、 L_K2Cimin；

(3) it enables

(4) judgeEach element whether exceed corresponding line maximum magnitude 0.8l_mi；IfIn there is no be less than 0.8l_mi's Element illustrates that the switch fixation of the traversal second level, which is completed, to be located atWhen third level switch all possible distribution transforming positions the case where； At this point, entering step (7) changes the fixed position of second level switch；IfIt is middle to exist less than 0.8l_miElement, illustrate the third level Switch is located atThree-level protective can be configured, then is updatedIt deletes and is wherein greater than 0.8l_miElement, be retained less than 0.8l_miMember Element, this season each second level position of the switch takeEach element, i.e.,Each third level position of the switch takesEach member Element, i.e.,

(5) according to position of the switch predeterminated position, according to Q after classifying to each conducting wire_fcFormula calculatesCorresponding expection Fault outage distribution transforming total capacity Q_fcIf Q_bestFor initial value or Q_fc< Q_best, then by minimum expected fault outage distribution transforming total capacity Q_bestIt is assigned a value of Q_fc, corresponding second level switch optimization positionIt is assigned a value of

(6) the fixed second level position of the switch is set toPlace, findsMatch for the 1st after the corresponding each place on line of each element Become, asks the impedance for calculating each distribution transforming, take minimum impedance therein；The positional distance backbone for calculating the corresponding each route of the impedance is asked to begin The distance at end, is denoted asEnable intermediate quantityIt enters back into step (4), loops through all qualified distribution transforming positions；

(7) second level position of the switch is changed, is foundImpedance after the corresponding each place on line of each element at the 1st distribution transforming, takes Minimum impedance Z therein_P2, the distance for calculating the positional distance backbone beginning of the corresponding each route of the impedance is sought, is denoted asIt updates The second level switchs minimum range L_K2Zmin、L_K2Fimin、L_K2CiminForCorresponding element, judgementWhether length range (0, 0.8l_mi) within, ifAll elements are all larger than 0.8l_mi, illustrate that all traversals are completed, enter step (8) output final optimization pass The result of calculating；IfThere are elements to be less than 0.8l_mi, illustrate that route protection is configured with the possibility advanced optimized, at this time basis Impedance Z at the switch of the second level_P2It recalculates to obtain the corresponding minimum impedance Z of third level switch_P3, ask the calculation impedance corresponding The distance at the positional distance backbone beginning of each route, is denoted asIt updates the third level and switchs minimum range L_K3Zmin、L_K3Fimin、 L_K3CiminForCorresponding element, judgementWhether in length range (0,0.8l_mi) within, ifAll elements are all larger than 0.8l_mi, Illustrate after changing second level switch position, can not continue to configure third level protection, all traversals are completed, and it is defeated to enter step (8) The result that final optimization pass calculates out；IfThere are elements to be less than 0.8l_mi, illustrate after changing the second level position of the switch, Ke Yipei Three-level protective is set, (3) is entered step and loops through calculating；

(8) pass through above-mentioned workflow management, finally obtain minimum expected fault outage distribution transforming total capacity Q_bestAnd its corresponding second level Switch optimizes positionExport calculated result.

9. one kind according to claim 7 is based on the smallest distribution line three-level protective Optimal Configuration Method of power failure capacity, It is characterized in that, when the distribution line has backbone, branch line and secondary branch line, the second level switch while appearing in backbone, On branch line or secondary branch line, i.e. the number of second level switch is greater than 1；

According to diversity switch whether is arranged on each route and the number of diversity switch is arranged, the conducting wire of whole route is divided into five Class:

(2) there was only second level switch on route；

(3) there was only third level switch on route；

(4) it is not switched on route, it is this kind of to have branch line and time branch line, it can be subdivided into before being entirely located in second level switch, entirely Portion is located between second and third grade switch, is entirely located in 3 microspecies after third level switch.