CN104485660B - A kind of distribution network reliability evaluation method based on oriented graph of a relation - Google Patents

Abstract

The invention discloses a kind of distribution network reliability evaluation method based on oriented graph of a relation; according to disconnecting switch segmenting function in the protection zone of chopper in power distribution network and feeder line, power distribution network is divided into the protection zone (CZ) of different levels and feeder line layer (FS) sets up the oriented graph of a relation of power distribution network; this oriented graph of a relation may be conveniently used the reliability assessment of power distribution network, and is directly used in containing distributed power source power distribution network.Main BasisASAIValue the biggest, reliability is the highest；SAIFI、SAIDI、CAIDIWithAENSValue the least, reliability is the highest, thus assesses the reliability of distribution network system.The present invention is widely used in the middle of the reliability assessment of medium voltage distribution network, overcomes the deficiency of existing fault mode consequences analysis method and block algorithm etc..

Description

A kind of distribution network reliability evaluation method based on oriented graph of a relation

Technical field

The present invention relates to power distribution network safe and reliable operation technical field, particularly relate to a kind of distribution based on oriented graph of a relation Net reliability estimation method.Both may be used for the reliability assessment of conventional electrical distribution net, it is also possible to for joining containing distributed power source The reliability assessment of electrical network.

Background technology

Power distribution network is the link in power system directly facing user, on customer power supply quality and the impact of power supply reliability The most direct, can improve by power distribution network being carried out reliability assessment power distribution network reliability, ensure power supply quality, promotion and Improve power industry production technology, manage, improve economic and social benefit etc. and all have and be of great significance.

The reliability estimation method widely used fault mode consequences analysis method (FMEA) of traditional power distribution network.Fault mode Consequences analysis method is the reliability data utilizing power distribution network element, sets up the fault mode consequence table that power distribution network runs, and analyzes every Individual event of failure and consequence thereof, the most comprehensively form reliability index.But when the structure complexity of power distribution network, fault mode consequence The foundation of table will be the most difficult, so directly utilizing fault mode consequences analysis method and carrying out the reliability assessment of Complicated Distribution Network be Extremely difficult.The network equivalent technology of Complex Distribution System Reliability Assessment in order to simplify the reliability assessment step of power distribution network, But when power distribution network contains more sub-feeder line, it will be difficult to obtain the equivalent network of Complicated Distribution Network.

The reliability estimation method of power distribution network also uses minimal path algorithm, minimal path algorithm when carrying out reliability assessment, First seek the minimal path of each load point, then consider the shadow to the reliability of load point of the element on minimal path and on non-minimum road respectively Ring, the impact of load point is converted in minimal path by certain criterion by the element on non-minimum road, then calculates minimal path The impact (including Equivalence effects) on load point reliability index of the middle element, thus try to achieve reliability index.

Power distribution network has a large capacity and a wide range, and network breaker in middle number of devices is numerous and its type, Various Functions, and sub-feeder line form is even Connecing the features such as complexity, these factors all add the difficulty of evaluating reliability of distribution network, and therefore research improves distribution network reliability The speed of assessment and precision are the Main Scientific Issues in this field current.Increasingly mature along with distributed generation technology, distribution Formula power supply (DG) is access in power distribution network, to distribution more and more by advantages such as its generation mode motility, environment friendly Structure and the operation of system create significant impact.Distributed power source (DG) accesses after power distribution network reliability to power distribution network actually Producing what impact, this is the most concerned problem of user and Utilities Electric Co..So, to the power distribution network containing distributed power source can It is the task of top priority by property assessment.

Summary of the invention

It is an object of the invention to provide a kind of distribution network reliability evaluation method based on oriented graph of a relation, it is possible to original On the basis of power distribution network network structure, assessed the reliability of distribution network system by the reliability index of load point, both can use The reliability assessment of power distribution network containing distributed power source can be applied to again in conventional electrical distribution net.

The technical solution used in the present invention is:

A kind of distribution network reliability evaluation method based on oriented graph of a relation, it is characterised in that: comprise the following steps:

A: gather the structured data of power distribution network to be assessed, electric parameter data and reliability parameters data bank；

B: the data gathered according to step A, carry out piecemeal and classification to power distribution network network structure；

Based on the difference of different elements fault impact in power distribution network, power distribution network is carried out in accordance with the following steps piecemeal and divides Level:

B1: the first section of chopper being directly connected with major network bus is divided into first order chopper, and is designated as CB11；

B2: under system failure running status, based on Depth Priority Algorithm with CB11 as starting point, starts Search for element along direction of tide on the feeder line at CB11 place, search a chopper or search the end of feeder line and then stop The only search in the direction, then start to proceed the search other directions from CB11, until the search of all of direction terminates； The protection zone of all elements composition CB11 then searched during this forms a block, and referred to as first class of protection district, is designated as CZ11；

B3: the method utilizing step B1 and B2, it is stipulated that the downstream direction of tide being joined directly together with CZ (i-1) (j-1) disconnected Road device is referred to as i-stage chopper, and protection zone corresponding to i-stage chopper is referred to as j-th stage protection zone, and search obtains other Chopper CBij and respective protection zone CZij, wherein, if CBij represents the jth chopper in i-stage protection zone； CZij represents the jth block in i-stage protection zone；Level and block will be divided into by whole power distribution network；

C: according to the partition of the level of protection zone CZij, sets up the oriented graph of a relation of initial power distribution network, the i.e. oriented relation of power distribution network Figure is that the protection zone by all levels is arranged to make up from top to bottom according to the first order, the second level, the third level ..., i-stage；

D: the feeder line in CZij is carried out segmentation；CZij is divided into different feeder line section by the position according to block switch FS, partiting step is as follows:

D1: first set in CZij all of feeder line as the feeder line section of the first level, be designated as FSij1；

D2: in CZij along power distribution network time properly functioning direction of tide search block switch, when searching 1st point During Duan Kaiguan, this all of feeder line in block switch downstream is revised as the feeder line section of the 2nd level, is designated as FSij2；

D3: according to the method for step D2, when searching-1 block switch of kth, by all of for this block switch downstream Feeder line is revised as the feeder line section of kth level, is designated as FSijk；Continue search for block switch, until all of block switch in CZij Till the most searched and segmentation；

E: obtained the feeder line section information in each protection zone by step D2 and D3, existing by embedding for the feeder line section information in each protection zone Enter in the oriented graph of a relation of power distribution network that step C is set up, obtain the oriented graph of a relation of final power distribution network；

F: the dependability parameter equivalence of element in feeder line section；

Owing in same feeder line section, the fault of element is all identical on the impact of load point, so, reliable to load point Property affect identical element be divided into an equivalent feeder line, respectively by equivalent fault rate λ_eWith equivalence γ repair time_eRepresent this The reliability index of feeder line section；

${\mathrm{\λ}}_e=\underset{i=1}{\overset{Nc}{\Σ}}{\mathrm{\λ}}_i---\left(1\right)$

${\mathrm{\γ}}_e=\frac{\underset{i=1}{\overset{Nc}{\Σ}}{\mathrm{\λ}}_i{\mathrm{\γ}}_i}{{\mathrm{\λ}}_e}---\left(2\right)$

In formula: N_CFor the number of element, λ in this equivalence feeder line section_iAnd γ_iIt is respectively i-th element in this equivalence feeder line section Fault rate and repair time；

G: when calculating failure rate and the annual power failure of distribution network load point according to the oriented graph of a relation of final power distribution network Between；

G1: when not containing distributed power source in system, the failure rate of load point and annual power off time, the most negative The calculating of the reliability index of lotus point；

It is assumed that Mi is the number of the feeder line section in the jth piecemeal of i-stage protection zone CZij, si is i-stage protection zone The connection node of CZij and i+1 level protection zone CZi+1, N (k) is load point k to the protection zone number between power supply, then load (3) and (4) failure rate and the annual power off time of some k are calculated by formula:

$\mathrm{\λ}\left(k\right)=\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=i}{\overset{M_i}{\Σ}}{\mathrm{\λ}}_{ij}+{\mathrm{\λ}}_{mg}---\left(3\right)$

$U\left(k\right)=\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=1}{\overset{s_i}{\Σ}}{\mathrm{\λ}}_{ij}{\mathrm{\γ}}_{ij}+\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=s_{i+1}}{\overset{M_i}{\Σ}}{\mathrm{\λ}}_{ij}{t}_{ds}+{\mathrm{\λ}}_{mg}{\mathrm{\γ}}_{mg}---\left(4\right)$

In formula, λ (k) and U (k) is respectively failure rate and the annual power off time of load point k；λ_ijAnd γ_ijIt is i-th The fault rate of jth feeder line section FSij and repair time in individual CZij；t_dsThe isolated operation time for switch；λ_mgAnd γ_mgIt is main The fault rate of net and repair time；

G2: when calculating containing distributed photovoltaic power, the failure rate of load point and average year power off time；

The history utilizing distributed power source goes out force data and stops to failure rate λ ' (k) and average year determining load point k Electricity time U ' (k), such as formula (5), (6) show:

${\mathrm{\λ}}^{\′}\left(k\right)=\frac{1}{N_{pv}}\underset{j=1}{\overset{N_{pv}}{\Σ}}\frac{max\{P_{ak}-P_j,0\}}{P_{ak}}\mathrm{\λ}\left(k\right)---\left(5\right)$

$U^{\′}\left(k\right)=\frac{1}{N_{pv}}\underset{j=1}{\overset{N_{pv}}{\Σ}}\frac{max\{P_{ak}-P_j,0\}}{P_{ak}}U\left(k\right)---\left(6\right)$

In formula, P_j(j=1,2 ..., N_PV) it is distributed photovoltaic power exerting oneself in jth hour；N_PVIt it is total hour Number；P_akPower for load point k；

G3: calculate containing load point failure rate during distributed diesel generating set and average year power off time；

Owing to diesel generating set is only to start when major network fault, therefore the access of diesel generating set can't subtract The frequency of power cut of few load point is merely capable of reducing the annual power off time of load point；Load point k failure rate λ " (k) and average year power off time U " (8) (k) (7) calculated with formula by formula:

(k)=λ ' (k) is (7) for λ " (k)=λ (k) or λ "

U " (k)=p_Udλ(k)t_di+p_DdU (k) or U " (k)=p_Udλ′(k)t_di+p_DdU′(k) ⑻

In formula, t_diFor the startup time of diesel-driven generator, P_UdAnd P_DdBe respectively diesel generating set availability and can not By rate；

H: calculate the reliability index of distribution network system, exports result of calculation；

Distribution network system reliability index is calculated by following formula:

In formula, when λ (k) and U (k) does not respectively contain distributed power source, failure rate and the annual of load point k stop When electricity time, λ ' (k) and U ' (k) are respectively failure rate and the annual power failure of load point k when containing distributed photovoltaic power Between, when λ " (k) and U " (k) is respectively failure rate and the annual power failure of load point k when containing distributed diesel generating set Between, it is in formula (3)-(10) failure rate and the annual power off time of load point k of correspondence；C_kIt it is kth load point The number of users connected；P_akFor kth load point power；R is load point set；

SAIFI refers to the average frequency of power cut that system System average interruption frequency, the most each user were subjected within the unit interval, Represented by the have a power failure ratio of total degree and number of users of user；SAIDI refers to system System average interruption duration, i.e. user institute in a year The System average interruption duration suffered, is represented by the ratio of customer outage hours summation with number of users；CAIDI refers to that user averagely has a power failure Persistent period, the average duration that the most each user had a power failure in 1 year every time, customer outage hours summation stop with user The ratio of electricity total degree represents；ASAI refers to averagely power availability, the most each user need for electricity in a year be met time Between percentage ratio, by actual power time total amount represent with the ratio of amount when requiring to power total；AENS refers to that system averagely lacks delivery, I.e. represented by the ratio of total short of electricity amount with total number of users；

I: the result calculated according to step H, the value according to ASAI is the biggest, and reliability is the highest；SAIFI, SAIDI, CAIDI and The value of AENS is the least, and reliability is the highest, thus assesses the reliability of distribution network system.

Power distribution network is drawn by the present invention according to disconnecting switch segmenting function in the protection zone of chopper in power distribution network and feeder line The protection zone (CZ) and the feeder line layer (FS) that are divided into different levels set up power distribution network directed graph, and this directed graph can be used easily In the reliability assessment of power distribution network, and it is directly used in containing distributed power source power distribution network.The present invention is widely used in medium voltage distribution network Reliability assessment in the middle of, overcome the deficiency of existing fault mode consequences analysis method and block algorithm etc...

Accompanying drawing explanation

Fig. 1 is the evaluating reliability of distribution network flow chart of the present invention；

Fig. 2 is a certain simple power distribution network network structure of the present invention；

Fig. 3 is piecemeal and the classification figure of the simple power distribution network network of the present invention；

Fig. 4 is the oriented graph of a relation of the simple power distribution network network containing CZ of the present invention；

Fig. 5 is the oriented graph of a relation of the simple power distribution network network containing CZ and FS of the present invention；

Fig. 6 be the present invention feeder line layer in element dependability parameter equivalence before；

Fig. 7 be the present invention feeder line layer in element dependability parameter equivalence after；

Fig. 8 is meter and the oriented graph of a relation of power distribution network of distributed power source of the present invention；

Fig. 9 is the present invention's and take no account of the oriented graph of a relation of power distribution network of distributed power source；

Figure 10 is certain community power distribution network network structure of the present invention.

Detailed description of the invention

As it is shown in figure 1, the present invention includes distribution network reliability evaluation method based on oriented graph of a relation, it is characterised in that: Comprise the following steps:

A: gather the structured data of power distribution network to be assessed, electric parameter data and reliability parameters data bank；

B: the data gathered according to step A, carry out piecemeal and classification to power distribution network network structure；

Based on the difference of different elements fault impact in power distribution network, power distribution network is carried out in accordance with the following steps piecemeal and divides Level:

B1: the first section of chopper being directly connected with major network bus is divided into first order chopper, and is designated as CB11；

B2: under system failure running status, based on Depth Priority Algorithm with CB11 as starting point, starts Search for element along direction of tide on the feeder line at CB11 place, search a chopper or search the end of feeder line and then stop The only search in the direction, then start to proceed the search other directions from CB11, until the search of all of direction terminates； The protection zone of all elements composition CB11 then searched during this forms a block, and referred to as first class of protection district, is designated as CZ11；

B3: the method utilizing step B1 and B2, it is stipulated that the downstream direction of tide being joined directly together with CZ (i-1) (j-1) disconnected Road device is referred to as i-stage chopper, and protection zone corresponding to i-stage chopper is referred to as j-th stage protection zone, and search obtains other Chopper CBij and respective protection zone CZij, wherein, if CBij represents the jth chopper in i-stage protection zone； CZij represents the jth block in i-stage protection zone；Level and block will be divided into by whole power distribution network；

C: according to the partition of the level of protection zone CZij, sets up the oriented graph of a relation of initial power distribution network, the i.e. oriented relation of power distribution network Figure is that the protection zone by all levels is arranged to make up from top to bottom according to the first order, the second level, the third level ..., i-stage；

D: the feeder line in CZij is carried out segmentation；CZij is divided into different feeder line section by the position according to block switch FS, partiting step is as follows:

D1: first set in CZij all of feeder line as the feeder line section of the first level, be designated as FSij1；

D2: in CZij along power distribution network time properly functioning direction of tide search block switch, when searching 1st point During Duan Kaiguan, this all of feeder line in block switch downstream is revised as the feeder line section of the 2nd level, is designated as FSij2；

D3: according to the method for step D2, when searching-1 block switch of kth, by all of for this block switch downstream Feeder line is revised as the feeder line section of kth level, is designated as FSijk；Continue search for block switch, until all of block switch in CZij Till the most searched and segmentation；

E: obtained the feeder line section information in each protection zone by step D2 and D3, existing by embedding for the feeder line section information in each protection zone Enter in the oriented graph of a relation of power distribution network that step C is set up, obtain the oriented graph of a relation of final power distribution network；

F: the dependability parameter equivalence of element in feeder line section；

Owing in same feeder line section, the fault of element is all identical on the impact of load point, so, reliable to load point Property affect identical element be divided into an equivalent feeder line, respectively by equivalent fault rate λ_eWith equivalence γ repair time_eRepresent this The reliability index of feeder line section；

${\mathrm{\λ}}_e=\underset{i=1}{\overset{Nc}{\Σ}}{\mathrm{\λ}}_i---\left(1\right)$

${\mathrm{\γ}}_e=\frac{\underset{i=1}{\overset{Nc}{\Σ}}{\mathrm{\λ}}_i{\mathrm{\γ}}_i}{{\mathrm{\λ}}_e}---\left(2\right)$

In formula: N_CFor the number of element, λ in this equivalence feeder line section_iAnd γ_iIt is respectively i-th element in this equivalence feeder line section Fault rate and repair time；

G: when calculating failure rate and the annual power failure of distribution network load point according to the oriented graph of a relation of final power distribution network Between；

G1: when not containing distributed power source in system, the failure rate of load point and annual power off time, the most negative The calculating of the reliability index of lotus point；

It is assumed that Mi is the number of the feeder line section in the jth piecemeal of i-stage protection zone CZij, si is i-stage protection zone The connection node of CZij and i+1 level protection zone CZi+1, N (k) is load point k to the protection zone number between power supply, then load (3) and (4) failure rate and the annual power off time of some k are calculated by formula:

$\mathrm{\λ}\left(k\right)=\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=i}{\overset{M_i}{\Σ}}{\mathrm{\λ}}_{ij}+{\mathrm{\λ}}_{mg}---\left(3\right)$

$U\left(k\right)=\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=1}{\overset{s_i}{\Σ}}{\mathrm{\λ}}_{ij}{\mathrm{\γ}}_{ij}+\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=s_{i+1}}{\overset{M_i}{\Σ}}{\mathrm{\λ}}_{ij}{t}_{ds}+{\mathrm{\λ}}_{mg}{\mathrm{\γ}}_{mg}---\left(4\right)$

In formula, λ (k) and U (k) is respectively failure rate and the annual power off time of load point k；λ_ijAnd γ_ijIt is i-th The fault rate of jth feeder line section FSij and repair time in individual CZij；t_dsThe isolated operation time for switch；λ_mgAnd γ_mgIt is main The fault rate of net and repair time；

G2: when calculating containing distributed photovoltaic power, the failure rate of load point and average year power off time；

The history utilizing distributed power source goes out force data and stops to failure rate λ ' (k) and average year determining load point k Electricity time U ' (k), such as formula (5), (6) show:

${\mathrm{\λ}}^{\′}\left(k\right)=\frac{1}{N_{pv}}\underset{j=1}{\overset{N_{pv}}{\Σ}}\frac{max\{P_{ak}-P_j,0\}}{P_{ak}}\mathrm{\λ}\left(k\right)---\left(5\right)$

$U^{\′}\left(k\right)=\frac{1}{N_{pv}}\underset{j=1}{\overset{N_{pv}}{\Σ}}\frac{max\{P_{ak}-P_j,0\}}{P_{ak}}U\left(k\right)---\left(6\right)$

In formula, P_j(j=1,2 ..., N_PV) it is distributed photovoltaic power exerting oneself in jth hour；N_PVIt it is total hour Number；P_akPower for load point k；

G3: calculate containing load point failure rate during distributed diesel generating set and average year power off time；

Owing to diesel generating set is only to start when major network fault, therefore the access of diesel generating set can't subtract The frequency of power cut of few load point is merely capable of reducing the annual power off time of load point；Load point k failure rate λ " (k) and average year power off time U " (8) (k) (7) calculated with formula by formula:

(k)=λ ' (k) is (7) for λ " (k)=λ (k) or λ "

U " (k)=p_Udλ(k)t_di+p_DdU (k) or U " (k)=p_Udλ′(k)t_di+p_DdU′(k) ⑻

In formula, t_diFor the startup time of diesel-driven generator, p_UdAnd p_DdBe respectively diesel generating set availability and can not By rate；

H: calculate the reliability index of distribution network system, exports result of calculation；

Distribution network system reliability index is calculated by following formula:

In formula, when λ (k) and U (k) does not respectively contain distributed power source, failure rate and the annual of load point k stop When electricity time, λ ' (k) and U ' (k) are respectively failure rate and the annual power failure of load point k when containing distributed photovoltaic power Between, when λ " (k) and U " (k) is respectively failure rate and the annual power failure of load point k when containing distributed diesel generating set Between, it is in formula (3)-(10) failure rate and the annual power off time of load point k of correspondence；C_kIt it is kth load point The number of users connected；P_akFor kth load point power；R is load point set；

SAIFI refers to the average frequency of power cut that system System average interruption frequency, the most each user were subjected within the unit interval, Represented by the have a power failure ratio of total degree and number of users of user；SAIDI refers to system System average interruption duration, i.e. user institute in a year The System average interruption duration suffered, is represented by the ratio of customer outage hours summation with number of users；CAIDI refers to that user averagely has a power failure Persistent period, the average duration that the most each user had a power failure in 1 year every time, customer outage hours summation stop with user The ratio of electricity total degree represents；ASAI refers to averagely power availability, the most each user need for electricity in a year be met time Between percentage ratio, by actual power time total amount represent with the ratio of amount when requiring to power total；AENS refers to that system averagely lacks delivery, I.e. represented by the ratio of total short of electricity amount with total number of users；

I: the result calculated according to step H, the value according to ASAI is the biggest, and reliability is the highest；SAIFI, SAIDI, CAIDI and The value of AENS is the least, and reliability is the highest, thus assesses the reliability of distribution network system.

Describe the detailed process of the present invention below in conjunction with the accompanying drawings in detail:

As shown in Figure 1, for the evaluating reliability of distribution network flow chart of the present invention.For ease of the thinking of the present invention is described, Being described institute of the present invention extracting method with a certain simple power distribution network network below, this simple network is as in figure 2 it is shown, from Fig. 2 It will be seen that be branched off multichannel branch by major network, in figure, LP is load point.

Step 1: gather power distribution network master data information

Gathering the information such as distribution net work structure data to be assessed, electric parameter data, reliability parameters data bank, these data are used Calculation of Reliability analysis in the later stage.

Step 2: power distribution network network structure is carried out piecemeal and classification

According to the direction of trend, the element in feeder line can be divided on the basis of certain equipment upstream element and downstream unit Part, is i.e. positioned at all elements in this equipment front by direction of tide and is referred to as the upstream element of this equipment, on the contrary, be referred to as this element Downstream components.Definition according to upstream and downstream element is known, the fault of chopper downstream components does not interferes with the element of upstream, but disconnected Road device upstream element fault can cause its all downstream components to stop transport.Affect not based on different elements fault in power distribution network With, power distribution network is carried out in accordance with the following steps piecemeal and classification:

The first section of chopper being directly connected with major network bus is divided into first order chopper by step 2.1, and is designated as CB11； In conjunction with Fig. 3 it will be seen that be joined directly together with major network is CB11 chopper.

Step 2.2 searches for the protection zone of chopper CB11；

Under system failure running status, start in CB11 institute for starting point with CB11 based on Depth Priority Algorithm Feeder line on search for element along direction of tide, search chopper or feeder line branch road end then stop the search of the direction, Element is searched for, until the search of all of direction terminates further along other directions.The group of all elements then searched during this Closing and constitute a block, this block is the protection zone of CB11, and is referred to as being first class of protection district, is designated as CZ11.Can see in conjunction with Fig. 3 Go out, on the feeder line at CB11 place, search for element, may search for chopper CB21 and normally closed switch, but normally closed switch is also It not the condition terminating search, so, continue search downwards, may search for chopper CB22, CB23, now terminate search, Then the CZ11 shown in Fig. 3 is the protection zone of chopper CB11.

Step 2.3 determines second level chopper and protection zone thereof

Specify that the chopper of the downstream direction of tide being joined directly together with CZ11 is referred to as second level chopper, and second level open circuit The protection zone that device is corresponding is referred to as protection zone, the second level.As it is shown on figure 3, CB21, CB22 and CB23 are second level chopper.Press The searching method stated in rapid 2.2 obtains CB21, CB22 and CB23 respective protection zone CZ21, CZ22 and CZ23, claims it For protection zone, the second level.

Step 2.4 is by that analogy, it is stipulated that the chopper of the downstream direction of tide being joined directly together with CZ (i-1) (j-1) is referred to as I-stage chopper, and protection zone corresponding to i-stage chopper be referred to as j-th stage protection zone, search obtains other chopper CBij and respective protection zone CZij thereof, wherein, if CBij represents the jth chopper in i-stage protection zone；CZij represents Jth block in i-stage protection zone；Level and block will be divided into by whole power distribution network.

Step 3, according to the partition of the level of protection zone CZij, sets up the oriented graph of a relation of initial power distribution network, the i.e. oriented pass of power distribution network Be figure be that the protection zone by all levels is arranged to make up from top to bottom according to the first order, the second level, the third level ..., i-stage.Have To graph of a relation: use the arrow with one direction instruction to be connected with each other the protection zone of different stage according to a definite sequence And the figure formed is called oriented graph of a relation.According to this definition, the simple network of Fig. 3 is converted into oriented graph of a relation, as shown in Figure 4.

Step 4 carries out segmentation to the feeder line in CZij

When CZij includes block switch, can by block switch the element fault in this CZij carried out every From, and then the load restoration because of fault stoppage in transit between power supply and block switch can be powered.Therefore, different segmentations in feeder line The power off time of interior element is different, therefore according to the position of block switch, CZij is divided into different feeder line section (FS). The partiting step of feeder line section is as follows:

First step 4.1 sets all of feeder line in each CZij as the feeder line section of the first level, is designated as FSij1；By Fig. 3 and Fig. 5 combines it can be seen that now, is divided in FS111, CZ, 21 and is divided into FS211, be divided in CZ22 in CZ11 FS221, CZ23 are divided into FS231, CZ31 is divided into FS311.

Step 4.2: along power distribution network direction of tide search block switch time properly functioning in CZij, when searching the During 1 block switch, this all of feeder line in block switch downstream is revised as the feeder line section of the 2nd level, is designated as FSij2；Such as CZ11 includes a normally closed switch, so, the downstream components of normally closed switch is the feeder line section of the 22nd level, then repaiies Change, now CZ11 is divided into FS111, FS112；CZ23 protection zone for another example, such as CZ11.

Step 4.3: according to the method for step step 4.2, when searching-1 block switch of kth, by this block switch The all of feeder line in downstream is revised as the feeder line section of kth level, is designated as FSijk；

Step 4.4 is further according to step 4.2 and step 4.3 method, and the feeder line section of the next CZi (j+1) of traversal, until owning CZ protection zone the most searched to.

Step 5 is obtained the feeder line section information in each protection zone by step 4.1-4.4, existing feeder line section information is embedded into by In the oriented graph of a relation of initial power distribution network formed in step 3, obtain the oriented graph of a relation of final power distribution network, as shown in Figure 5.By step 5 it can be seen that be divided into carried out feeder line segmentation, such as first class of protection district in each protection zone in two feeder line section FS111, FS112。

The dependability parameter equivalence of element in step 6 feeder line layer FS

Owing in same feeder line layer, the fault of element is all identical on the impact of load point, as shown in Figure 6, Figure 7, therefore In order to simplify the network structure of reliability assessment, the element that load point reliability effect is identical will be divided into an equivalence feedback Line, this equivalence does not reduce Evaluation accuracy, respectively with equivalent fault rate (λ_e) and equivalence (γ repair time_e) represent this feedback The reliability index of line layer.

${\mathrm{\λ}}_e=\underset{i=1}{\overset{Nc}{\Σ}}{\mathrm{\λ}}_i---\left(1\right)$

${\mathrm{\γ}}_e=\frac{\underset{i=1}{\overset{Nc}{\Σ}}{\mathrm{\λ}}_i{\mathrm{\γ}}_i}{{\mathrm{\λ}}_e}---\left(2\right)$

In formula: N_CFor the number of element, λ in this equivalence feeder line layer_iAnd γ_iIt is respectively i-th element in this equivalence feeder line layer Fault rate and repair time.

Step 7 calculates the load point failure rate under different condition and average year power off time, as shown in Figure 8, Figure 9, For whether containing the difference of the oriented graph of a relation of power distribution network of distributed power source.

Step 7.1: calculate without load point failure rate during distributed power source and average year power off time.

The calculating of distribution Power System Reliability index is described below in detail: accompanying drawing 10 show containing DG community with embodiment Power distribution network network structure.This distribution network load comprises six office building loads (B1, B2, B3, B5, B6, B7), three dormitory loads (D1, D2, D3), a gymnasium load (GM) and a fitness center load (FC).The roof of office building B7 is provided with specified Capacity is the photovoltaic unit of 20kW, and in addition to gymnasium and fitness center, remaining nine load is provided with diesel generating set conduct Stand-by power supply, when major network breaks down, stand-by power supply is powered to important load.

It is assumed that M_iIt is i-stage protection zone (CZ_i) number of feeder line section in interior jth piecemeal, s_iIt it is i-stage protection zone CZ_iWith i+1 level protection zone CZ_i+1Connection node, N (k) is load point k to the protection zone number between power supply, then without point Failure rate and the average year power off time of load point k during cloth power supply are calculated by formula (3) and formula (4):

$\mathrm{\λ}\left(k\right)=\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=i}{\overset{M_i}{\Σ}}{\mathrm{\λ}}_{ij}+{\mathrm{\λ}}_{mg}---\left(3\right)$

$U\left(k\right)=\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=1}{\overset{s_i}{\Σ}}{\mathrm{\λ}}_{ij}{\mathrm{\γ}}_{ij}+\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=s_{i+1}}{\overset{M_i}{\Σ}}{\mathrm{\λ}}_{ij}{t}_{ds}+{\mathrm{\λ}}_{mg}{\mathrm{\γ}}_{mg}---\left(4\right)$

In formula, λ (k) and U (k) is respectively failure rate and the annual power off time of load point k；λ_ijAnd γ_ijIt is i-th The fault rate of jth feeder line section FS and repair time in individual CZ；t_dsThe isolated operation time for switch；λ_mgAnd γ_mgFor major network Fault rate and repair time.

Step 7.2: calculate containing load point failure rate during distributed photovoltaic power and average year power off time

When load point k is connected to distributed photovoltaic power, photo-voltaic power supply contribute to reduce load point failure rate and Annual power off time.For being connected to the load point of photo-voltaic power supply, access meeting when major network fault in time due to photo-voltaic power supply The fault rate of load point and repair time are produced impact, goes out force data hence with the history of photo-voltaic power supply and calculate and divide Failure rate λ (k) of load point k during cloth photo-voltaic power supply and average year power off time U (k), such as formula (5) and formula (6) institute Show:

${\mathrm{\λ}}^{\′}\left(k\right)=\frac{1}{N_{pv}}\underset{j=1}{\overset{N_{pv}}{\Σ}}\frac{max\{P_{ak}-P_j,0\}}{P_{ak}}\mathrm{\λ}\left(k\right)---\left(5\right)$

$U^{\′}\left(k\right)=\frac{1}{N_{pv}}\underset{j=1}{\overset{N_{pv}}{\Σ}}\frac{max\{P_{ak}-P_j,0\}}{P_{ak}}U\left(k\right)---\left(6\right)$

In formula, P_j(j=1,2 ..., N_PV) it is distributed photovoltaic power exerting oneself in jth hour；N_PVIt it is total hour Number.

Step 7.3: calculate containing load point failure rate during distributed diesel generating set and average year power off time

For important power load, often access diesel generating set as stand-by power supply using automatic transfer switch.Due to Diesel generating set is only to start when major network fault, and therefore the access of diesel generating set can't reduce stopping of load point Electricity number of times is merely capable of reducing the annual power off time of load point.When considering the diesel-driven generator group model of two states, negative Failure rate λ (k) of lotus point k and average year power off time U (k) are calculated by formula (7) and formula (8):

λ " (k)=λ (k) or λ " (k)=λ ' (k) (7)

U " (k)=p_Udλ(k)t_di+p_DdU (k) or U " (k)=p_Udλ′(k)t_di+p_DdU′(k) (8)

In formula, t_diFor the startup time of diesel-driven generator, p_UdAnd p_DdBe respectively diesel generating set availability and can not By rate.

Step 8: calculate the reliability index of distribution system

Obtain in power distribution network after the reliability index of each load point, according to the definition of the reliability index of distribution system just Can directly calculate the reliability index of system.System System average interruption frequency (SAIFI) refers to each user institute within the unit interval The average frequency of power cut being subjected to, is represented by the have a power failure ratio of total degree and number of users of user；System System average interruption duration (SAIDI) System average interruption duration that user was suffered in a year is referred to, by the ratio of customer outage hours summation with number of users Represent；User's System average interruption duration (CAIDI) refers to the average duration that each user had a power failure in 1 year every time, by with The have a power failure ratio of total degree of family power off time summation and user represents；Availability of averagely powering (ASAI) refers to that each user is in 1 year The percentage of time that need for electricity is met, by actual power time total amount represent with the ratio of amount when requiring to power total；System The average delivery (AENS) that lacks of system is represented by the ratio of total short of electricity amount with total number of users.

Distribution Power System Reliability index is calculated by formula (9)-(13):

In formula, when λ (k) and U (k) does not respectively contain distributed power source, failure rate and the annual of load point k stop When electricity time, λ ' (k) and U ' (k) are respectively failure rate and the annual power failure of load point k when containing distributed photovoltaic power Between, when λ " (k) and U " (k) is respectively failure rate and the annual power failure of load point k when containing distributed diesel generating set Between, it is in formula (3)-(10) failure rate and the annual power off time of load point k of correspondence；C_kIt it is kth load point The number of users connected；P_akFor kth load point power；R is load point set.

The reliability basic data gathered according to step 1, calculates when not containing distributed power source according to formula (9)-(13) Distribution Power System Reliability index result of calculation result is as shown in table 1 below:

Table 1

Building title	SAFI	SAIDI	ASAI (%)	AENS
					B1	1.0765	7.4127	99.9154	498.4270
B2	1.0782	7.4774	99.9146	537.5650
					B3	1.0775	7.5019	99.9144	394.2440
B5	1.0775	7.4704	99.9147	1042.1000
					B6	1.0782	7.4774	99.9146	495.0040
B7	1.0775	7.5019	99.9144	848.6900
					D1	1.0800	7.6839	99.9123	659.6120
D2	1.0800	7.6839	99.9123	318.9080
					D3	1.0800	7.6839	99.9123	612.3560
GM	1.0800	7.6839	99.9123	218.7610
					FC	1.0800	7.6839	99.9123	670.8050
Whole system	1.0784	7.5430	99.9139	578.123

System System average interruption frequency (SAIFI), system System average interruption duration (SAIDI), user as can be seen from Table 1 It is the highest that System average interruption duration (CAIDI), system averagely lack delivery (AENS), and the stability of distribution network system, power supply can Relatively low by property ratio；Availability of averagely powering (ASAI) is the highest, and the power supply performance of distribution network system is the best.

Calculate containing distribution Power System Reliability index result of calculation during distributed power source as shown in table 2 below, due to distributed Power supply is installed only on B7, and therefore distributed power source only improves the reliability index of B7 building after accessing, and it is reliable that other are built Property index is identical with above-mentioned computational methods.

Table 2

Building title	SAFI	SAIDI	ASAI (%)	AENS	CRASAI(%)
						B7	1.06800	7.4355	99.9151	843.927	0.0007
Whole system	1.07753	7.5369	99.9140	577.690	0.0001

As shown in table 3 below containing distribution Power System Reliability index result of calculation during diesel generating set:

Table 3

Building title	SAFI	SAIDI	ASAI (%)	AENS	CRASAI(%)
						B1	1.07648	5.60104	99.9361	453.607	0.0207
B2	1.07823	6.01542	99.9313	432.011	0.0167
						B3	1.07753	5.66842	99.9353	386.396	0.0209
B5	1.07753	5.03605	99.9425	496.948	0.0278
						B6	1.07823	5.04077	99.9425	235.016	0.0279
B7	1.06800	4.99091	99.9430	499.209	0.0286
						D1	1.07998	5.17982	99.9409	304.183	0.0286
D2	1.07998	5.17982	99.9409	242.658	0.0286
						D3	1.07998	5.17982	99.9409	476.159	0.0286
GM	1.07998	7.68390	99.9123	218.761	0
						FC	1.07998	7.68390	99.9123	670.805	0
Whole system	1.07753	5.52559	99.9369	399.156	0.0230

Claims (1)

1. a distribution network reliability evaluation method based on oriented graph of a relation, it is characterised in that: comprise the following steps:

A: gather the structured data of power distribution network to be assessed, electric parameter data and reliability parameters data bank；

B: the data gathered according to step A, carry out piecemeal and classification to power distribution network network structure；

Based on the difference of different elements fault impact in power distribution network, power distribution network is carried out in accordance with the following steps piecemeal and classification:

B1: the first section of chopper being directly connected with major network bus is divided into first order chopper, and is designated as CB11；

B2: under system failure running status, based on Depth Priority Algorithm with CB11 as starting point, starts in CB11 institute Feeder line on search for element along direction of tide, search a chopper or search the end of feeder line and then stop the party Search upwards, then start to proceed the search other directions from CB11, until the search of all of direction terminates；Then this mistake The protection zone of all elements composition CB11 searched in journey forms a block, and referred to as first class of protection district, is designated as CZ11；

B3: the method utilizing step B1 and B2, it is stipulated that with the chopper of the downstream direction of tide that CZ (i-1) (j-1) is joined directly together The protection zone that referred to as i-stage chopper, and i-stage chopper is corresponding is referred to as j-th stage protection zone, and search obtains the disconnected of other Road device CBij and respective protection zone CZij thereof, wherein, if CBij represents the jth chopper in i-stage protection zone；CZij Represent the jth block in i-stage protection zone；Level and block will be divided into by whole power distribution network；

C: according to the partition of the level of protection zone CZij, sets up the oriented graph of a relation of initial power distribution network, i.e. the oriented graph of a relation of power distribution network is It is arranged to make up from top to bottom according to the first order, the second level, the third level ..., i-stage by the protection zone of all levels；

D: the feeder line in CZij is carried out segmentation；CZij is divided into different feeder line section FS by the position according to block switch, draws As follows:

D1: first set in CZij all of feeder line as the feeder line section of the first level, be designated as FSij 1；

D2: in CZij along power distribution network time properly functioning direction of tide search block switch, open when searching the 1st segmentation Guan Shi, is revised as this all of feeder line in block switch downstream the feeder line section of the 2nd level, is designated as FSij2；

D3: according to the method for step D2, when searching-1 block switch of kth, by this all of feeder line in block switch downstream It is revised as the feeder line section of kth level, is designated as FSijk；Continue search for block switch, until all of block switch all quilts in CZij Till search segmentation；

E: obtained the feeder line section information in each protection zone by step D2 and D3, existing feeder line section information in each protection zone embedding walks In the oriented graph of a relation of power distribution network that rapid C sets up, obtain the oriented graph of a relation of final power distribution network；

F: the dependability parameter equivalence of element in feeder line section；

Owing in same feeder line section, the fault of element is all identical on the impact of load point, so, to load point reliability shadow Ring identical element and be divided into an equivalent feeder line, respectively by equivalent fault rate λ_eWith equivalence γ repair time_eRepresent this feeder line The reliability index of section；

${\mathrm{\λ}}_e=\underset{i=1}{\overset{Nc}{\Σ}}{\mathrm{\λ}}_i---\left(1\right)$

${\mathrm{\γ}}_e=\frac{\underset{i=1}{\overset{Nc}{\Σ}}{\mathrm{\λ}}_i{\mathrm{\γ}}_i}{{\mathrm{\λ}}_e}---\left(2\right)$

In formula: N_CFor the number of element, λ in this equivalence feeder line section_iAnd γ_iIt is respectively the event of i-th element in this equivalence feeder line section Barrier rate and repair time；

G: calculate failure rate and the annual power off time of distribution network load point according to the oriented graph of a relation of final power distribution network；

G1: when not containing distributed power source in system, the failure rate of load point and annual power off time, i.e. load point The calculating of reliability index；

It is assumed that Mi is the number of the feeder line section in the jth piecemeal of i-stage protection zone CZij, si be i-stage protection zone CZij with The connection node of i+1 level protection zone CZi+1, N (k) is load point k to the protection zone number between power supply, then load point k (3) and (4) failure rate and annual power off time are calculated by formula:

$\mathrm{\λ}\left(k\right)=\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=i}{\overset{M_i}{\Σ}}{\mathrm{\λ}}_{ij}+{\mathrm{\λ}}_{mg}---\left(3\right)$

$U\left(k\right)=\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=1}{\overset{s_i}{\Σ}}{\mathrm{\λ}}_{ij}{\mathrm{\γ}}_{ij}+\underset{i=1}{\overset{N\left(k\right)}{\Σ}}\underset{j=s_{i+1}}{\overset{M_i}{\Σ}}{\mathrm{\λ}}_{ij}{t}_{ds}+{\mathrm{\λ}}_{mg}{\mathrm{\γ}}_{mg}---\left(4\right)$

In formula, λ (k) and U (k) is respectively failure rate and the annual power off time of load point k；λ_ijAnd γ_ijFor i-th The fault rate of jth feeder line section FSij and repair time in CZij；t_dsThe isolated operation time for switch；λ_mgAnd γ_mgFor major network Fault rate and repair time；

G2: when calculating containing distributed photovoltaic power, the failure rate of load point and average year power off time；

When the history utilizing distributed power source goes out force data to determine that failure rate λ ' (k) of load point k and average year have a power failure Between U ' (k), such as formula (5), (6) show:

${\mathrm{\λ}}^{\′}\left(k\right)=\frac{1}{N_{pv}}\underset{j=1}{\overset{N_{pv}}{\Σ}}\frac{max\{P_{ak}-P_j,0\}}{P_{ak}}\mathrm{\λ}\left(k\right)---\left(5\right)$

$U^{\′}\left(k\right)=\frac{1}{N_{pv}}\underset{j=1}{\overset{N_{pv}}{\Σ}}\frac{\max \{P_{ak}-P_j,0\}}{P_{ak}}U\left(k\right)---\left(6\right)$

In formula, P_j(j=1,2 ..., N_PV) it is distributed photovoltaic power exerting oneself in jth hour；N_PVIt it is total hourage；P_ak Power for load point k；

G3: calculate containing load point failure rate during distributed diesel generating set and average year power off time；

Owing to diesel generating set is only to start when major network fault, therefore the access of diesel generating set can't reduce negative The frequency of power cut of lotus point is merely capable of reducing the annual power off time of load point；Failure rate λ of load point k " (k) peace All years power off time U " (8) (k) (7) calculated with formula by formula:

(k)=λ ' (k) is (7) for λ " (k)=λ (k) or λ "

U " (k)=p_Udλ(k)t_di+p_DdU (k) or U " (k)=p_Udλ′(k)t_di+p_DdU′(k) ⑻

In formula, t_diFor the startup time of diesel-driven generator, p_UdAnd p_DdIt is respectively the availability of diesel generating set and unavailable Rate；

H: calculate the reliability index of distribution network system, exports result of calculation；

Distribution network system reliability index is calculated by following formula:

In formula, when when λ (k) and U (k) respectively do not contain distributed power source, the failure rate of load point k and annual have a power failure Between, λ ' (k) and U ' (k) is respectively failure rate and annual power off time, the λ of load point k when containing distributed photovoltaic power " K " (k) is respectively failure rate and the annual power off time of load point k when containing distributed diesel generating set, i.e. for () and U Failure rate and annual power off time for load point k corresponding in formula (3)-(10)；C_kIt is that kth load point connects Number of users；P_akFor kth load point power；R is load point set；

SAIFI refers to the average frequency of power cut that system System average interruption frequency, the most each user were subjected within the unit interval, by with Power failure total degree in family represents with the ratio of number of users；SAIDI refers to that system System average interruption duration, i.e. user were suffered in 1 year System average interruption duration, the ratio of customer outage hours summation with number of users represent；CAIDI refers to that user averagely has a power failure and continues Time, the average duration that the most each user had a power failure in 1 year every time, customer outage hours summation have a power failure always with user The ratio of number of times represents；ASAI refers to averagely power availability, the most each user time that need for electricity is met in 1 year hundred Proportion by subtraction, by actual power time total amount represent with the ratio of amount when requiring to power total；AENS refers to that system averagely lacks delivery, i.e. by Total short of electricity amount represents with the ratio of total number of users；

I: the result calculated according to step H, the value according to ASAI is the biggest, and reliability is the highest；SAIFI, SAIDI, CAIDI and AENS Value the least, reliability is the highest, thus assesses the reliability of distribution network system.