CN104766247A - Full voltage class power grid reliability calculation method - Google Patents

Abstract

The invention discloses a full voltage class power grid reliability calculation method. The full voltage class power grid reliability calculation method comprises a conventional power grid reliability calculation method, a reliability calculation method based on the coordination of the reliability and the economy and a power grid difference reliability calculation method based on the sensitivity. The conventional power grid reliability calculation method comprises an accurate calculation method for calculating the system reliability by minimum path sets, an accurate calculation method for calculating the system failure probability by minimum cut sets and an approximate calculation method for calculating the system failure probability by the minimum cut sets. According to the full voltage class power grid reliability calculation method, the reliability and the economy are uniformly taken into account and applied in the power grid work, the sensitivity index of reliability evaluation is established, therefore, the problem that which level the reliability can be improved on the condition that the investment is given can be solved, the problem that how to reduce the system construction cost to the minimum while the reliability requirement is achieved can be solved, and the sensitivity index can research the influence of the subtle change of element reliability parameters on the system reliability.

Description

A kind of computing method of full voltage level Grid reliability

Technical field

The present invention relates to electric power network technique field, specifically a kind of computing method of full voltage level Grid reliability.

Background technology

Along with the appearance of current China extra-high voltage grade and the progressively formation of national bulk transmission grid, indicate that profound change is occurring China's electrical network, and exert far reaching influence to the development of line voltage grade, grid structure.According to the objective demand at " in the middle of strengthening two, simplification " in current Electric Power Network Planning, construction, emphasis is needed to solve extra-high voltage and power distribution network " two weakness " problem.Therefore, in Electric Power Network Planning process of construction, on the one hand, the formation accelerating extra-high voltage bulk transmission grid is needed; On the other hand, also should strengthen the construction of full voltage level Grid and transformation dynamics, reasonable disposition city and country electric pressure, adjustment electric network composition; Meet with socio-economic development and people's livelihood workload demand, suitable provides power supply reliability, reduces loss of outage.Only in this way, could realize further making that major network is strong, distribution reliable, scheduling flexibly, the target of economical operation, eco-friendly novel power grid.

The grid structure of rational electric pressure and science is the basis that electrical network provides safety, firm power to supply to user.The most basic object of electrical network is to provide safe and reliable electric power supply to user, and final purpose is to obtain best social.The grid structure of rational electric pressure and science is the basis that electrical network provides safety, firm power to supply to user.

Summary of the invention

The object of the present invention is to provide a kind of computing method preventing from blindly increasing investment, full voltage level Grid reliability that purpose is strong, to solve the problem proposed in above-mentioned background technology.

For achieving the above object, the invention provides following technical scheme:

A kind of computing method of full voltage level Grid reliability, comprise normal grid reliability calculation method, the reliability calculation method coordinated mutually based on reliability and economy and the electrical network otherness reliability calculation method based on sensitivity, described normal grid reliability calculation method comprises the accurate computing method being asked system reliability by minimal path sets, ask the accurate computing method of System failure probability by minimal cut set and asked the approximate calculation method of System failure probability by minimal cut set, in the described reliability calculation method coordinated mutually based on reliability and economy, the horizontal Rm of optimal reliability is the corresponding reliability level of reliability marginal cost when equaling reliability marginal contribution, described based in the electrical network otherness reliability calculation method of sensitivity, element is under arms after T time, the probability P a that ageing failure occurs in its follow-up time interval Δ t is:

$P_a=1-e^{{\left(\frac{T}{\mathrm{\η}}\right)}^{\mathrm{\β}}-{\left(\frac{T+\mathrm{\Δt}}{\mathrm{\η}}\right)}^{\mathrm{\β}}}.$

As the further scheme of the present invention: the described reliably working probability RS of system in the accurate computing method of system reliability that asked by minimal path sets is:

$R_s=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}P\left\{L_{\mathrm{idis}}\right\}.$

As the further scheme of the present invention: the described failure probability Qs of system in the accurate computing method of System failure probability that asked by minimal cut set is:

$\begin{array}{c}{Q}_S=P\left\{\begin{array}{cccc}{C}_1& C_2& ...& C_l\end{array}\right\}\\ =\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{C_i\right\}-\underset{i<j=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{\begin{array}{cc}{C}_i& C_j\end{array}\right\}+...\\ +{(-1)}^{l-1}P\left\{\begin{array}{ccc}{C}_1& C_2& C_l\end{array}\right\}.\end{array}.$

As the present invention's further scheme: the described failure probability Qs of system in the approximate calculation method of System failure probability that asked by minimal cut set is:

$\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{C_i\right\}-\underset{i<j=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{\begin{array}{cc}{C}_i& C_j\end{array}\right\}\&le;Q_S\&le;\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{C_i\right\}.$

Compared with prior art, the invention has the beneficial effects as follows:

The present invention is on the basis of normal grid Calculation of Reliability, reliability and economy unification are considered and be applied in network operation, and establish the sensitivity index of reliability assessment, reliability and the unified consideration of economy both can be applied to line voltage hierarchical selection, electric network structure optimization, can be applicable to again the operation maintenance of electrical network, for network operation opens new road, solve and reliability can be made to bring up to the problem of how level under the condition of given investment, solve and how while reaching reliability requirement, the expenditure of construction of system to be reduced to minimum problem, solve the problem how making limited fund system reliability be reached optimum, solve in current electrical network and blindly increase investment, unlimited pursuit power supply reliability causes the problem of investment waste, the impact that the subtle change that sensitivity index studies component reliability parameter causes Reliability Index, the bottleneck of system for restricting reliability can be found exactly, the weak link increasing invest in the transformation of real estate is needed most in certainty annuity, can carry out on the basis of reliability cost/performance evaluation at the planning different to electrical network, optimization, modification scheme, determine optimum scheme.

Accompanying drawing explanation

Fig. 1 is the example network figure calculating minimal path sets and minimal cut set in the present invention.

Fig. 2 is nodes system non-directed graph of the present invention in Fig. 1.

Fig. 3 is reliability cost in the present invention/performance analysis curve map.

Fig. 4 is that in the present invention, economic evaluation model framework chart is built in distribution.

Fig. 5 is the graph of a relation of element failure rate and power supply reliability index ASAI in the present invention.

Fig. 6 is the graph of a relation of element repair time and power supply reliability index ASAI in the present invention.

Fig. 7 is the tub curve figure of equipment failure rate in the present invention.

Fig. 8 is ageing equipment failure probability schematic diagram in the present invention.

Fig. 9 is the WeibUll distribution crash rate of failure dense function and the relation schematic diagram between the time in the present invention.

Embodiment

Be described in more detail below in conjunction with the technical scheme of embodiment to this patent.

A kind of computing method of full voltage level Grid reliability, comprise normal grid reliability calculation method, the reliability calculation method coordinated mutually based on reliability and economy and the electrical network otherness reliability calculation method based on sensitivity, described normal grid reliability calculation method comprises the accurate computing method being asked system reliability by minimal path sets, ask the accurate computing method of System failure probability by minimal cut set and asked the approximate calculation method of System failure probability by minimal cut set, in the described reliability calculation method coordinated mutually based on reliability and economy, the horizontal Rm of optimal reliability is the corresponding reliability level of reliability marginal cost when equaling reliability marginal contribution, described based in the electrical network otherness reliability calculation method of sensitivity, element is under arms after T time, the probability P a that ageing failure occurs in its follow-up time interval Δ t is:

$P_a=1-e^{{\left(\frac{T}{\mathrm{\&eta;}}\right)}^{\mathrm{\&beta;}}-{\left(\frac{T+\mathrm{\&Delta;t}}{\mathrm{\&eta;}}\right)}^{\mathrm{\&beta;}}}$ Formula 1

Connect the set of any two internodal arcs, be called the Yi Tiaolu of these two nodes, between two nodes, the set on all roads is referred to as road collection, does not all form road after removing any arc in Ruo Yitiao road, Ze Chengzhetiao road is minimal path, and the set be made up of minimal path is referred to as minimal path sets.

The computing method of described minimal path sets comprise connection matrix method, boolean's new determinant method and search procedure, in connection matrix method, a given network S having a n node, define corresponding n rank Matrix C=[cij], n rank Matrix C is the incidence matrix of network S, and the incidence matrix of network described in Fig. 1 is:

$C=\left[\begin{array}{cccc}0& x_1& x_2& 0\\ 0& 0& x_3& x_4\\ 0& x_3& 0& x_5\\ 0& 0& 0& 0\end{array}\right]$ Formula 2

Definition multiplying C2=[c [2] _ij],

${c^{\left(2\right)}}_{\mathrm{ij}}=\underset{k=1}{\overset{n}{\mathrm{\&Sigma;}}}{C}_{\mathrm{ik}}\&CenterDot;C_{\mathrm{kj}}$ Formula 3

Wherein, c [2] expression is the entirety of 2 minimal path sets from an i to the length of a j, if c [2] _ijbe less than 2, namely only have an arc, then should by c [2] _ijchange zero into.

In like manner definable Cr=[c [r] _ij], r=1,2 ..., wherein c [r] _ijthe length be meant between an i to some j be the entirety of the minimal path sets of r.

Have in the network S of n node at one, the maximum length≤n-1 of minimal path between any two nodes, so for incidence matrix C, if r >=n, must have Cr=0.Therefore, can obtain any two node i, the minimal path sets entirety between j is:

$c_{\mathrm{ij}}^r_{r=1}^{n-1},(c_{\mathrm{ij}}^{\left(1\right)}=c_{\mathrm{ij}})$ Formula 4

Therefore, by repeatedly multiplication just can in the hope of the entirety of minimal path sets.Minimal path sets between input node and output node, then only need to obtain C2 ..., a certain column element in Cn-1.

Such as, refer to Fig. 1, input node is 1, and output node is 4, as long as namely obtain C2 ..., the 4th column element in Cn-1, C24 represents the 4th column element of C2, and C34 represents the 4th column element of C3, as shown in table 1:

4th column element table between table 1 input node and output node

Therefore, from point 1 to the minimal path sets S of point 4 be:

S=x ₁x ₄+ x ₂x ₅+ x ₁x ₃x ₅+ x ₂x ₃x ₄formula 5

When namely having at least a minimal path sets to be in serviceable condition, system is just in serviceable condition.

The incidence matrix C of a given network S in described boolean's new determinant method, constructs one and is added with unit matrix U and the C of dimension with incidence matrix C, obtain Matrix C+U.If this matrix dimension is n × n, the row of input node corresponding in this matrix and the element of row that corresponds to output node is scratched, form a determinant | S|, will | what S| expanded into boolean product can obtain the minimal path sets of network with limit.

If ask the minimal path sets in Fig. 1 by boolean's new determinant method, then

$C+U=\left[\begin{array}{cccc}1& x_1& x_2& 0\\ 0& 1& x_3& x_4\\ 0& x_3& 1& x_5\\ 0& 0& 0& 1\end{array}\right]$ Formula 6

Determinant | S| is: $\left|S\right|=\left[\begin{array}{ccc}{x}_1& x_2& 0\\ 1& x_3& x_4\\ x_3& 1& x_5\end{array}\right]$ Formula 7

Determinant | S| can obtain minimal path sets after launching:

S=x ₁x ₄+ x ₂x ₅+ x ₁x ₃x ₅+ x ₂x ₃x ₄formula 5

Described search procedure is that find out whole minimal path sets, search procedure comprises depth-first search and BFS (Breadth First Search) method successively to output node search by the input node of network.

Fig. 2 please be participate in, during described depth-first search, DFS is in access figure after the V of certain a starting point, by V, access its arbitrary connect Vertex W1, then from Wl, access and W1 adjoin but the summit W2 also do not accessed, and then from W2, carry out similar access, so go on, until the summit U of all accessed mistake of all adjacent vertexes.Then, return a step, the summit once just accessed before falling back on, see whether also have other not visited adjacent vertexes.If had, then access this summit, from then on set out in summit more afterwards, carries out and aforementioned similar access; If no, just return a stepping line search again.Repeat said process, until all accessed mistake in all summits in connected graph.

The process of depth-first search traversal is: from node V1, starts search, finds V2, because V2 is not accessed, then carry out search V4 from V2, all of its neighbor node due to V4 is all accessed have been crossed, so start backtracking, get back to V1 through V4, V2 successively, then search V6 through V1, V3 and then recall, eventually pass V2, V3 to V7, now all node searchings are complete, its search procedure is V1-V2-V4, V1-V2-V5-V7, V1-V3-V6.

During described BFS (Breadth First Search) method, in access figure after the V of certain a starting point, by V, access the adjacent vertex Wl of each not accessed mistake of V successively, W2 ... Wt, and then sequential access Wl, W2 ... the adjacent vertex of these not accessed mistakes all of Wt.Again from the summit accessed, visit again the adjacent vertex of their all also not accessed mistakes, so go down, until all summits are all accessed in figure.

The process that in Fig. 2, BFS (Breadth First Search) is gone through is: from first node VI, the adjacent node of search V1, because V1 does not have adjacent node, then second layer V2 and its adjacent node V3 of non-directed graph is searched for, then the third layer V4 of this non-directed graph and adjacent node V5 and V6 thereof is searched for, final search the 4th layer of V7 node, until all nodes have all been searched for.Its search procedure is V1-V2-V3, V2-V4-V5, V3-V6, V5-V7.

The minimal path sets of generally trying to achieve is compatible, ask system works probability very complicated by compatible minimal path sets, therefore compatible minimal path sets is first turned to inconsistent minimal path sets, and then ask the work probability of system, compatible minimal path sets is first turned to inconsistent minimal path sets, one process is called non cross link process, and the method for non cross link process leaves out to leave algorithm.

It is described that to leave out the concrete steps leaving algorithm as follows:

(1) a n-dimensional vector Ei is defined to each minimal path sets Si, i=1,2 ..., each component of n, vectorial Ei is a binary digit, and the numeral that the element comprised in minimal path sets Si is corresponding is 1, and the numeral that the element do not comprised is corresponding is 0, then $T_j=\underset{j=1}{\overset{n}{\mathrm{\&Sigma;}}}{E}_j(j=\mathrm{1,2},...,n)$ Formula 8;

(2) compare Tj and Ej, if in Tj some nonzero element position on the element of Ej be zero, so just by they descending or ascending positions writing down them of location number in Tj, make these location labels be respectively K1, K2 ... Kr;

(3) Ej to Kr be decomposed into two component Ej (Kr) and they respectively with 1 and-1 replace Ej to zero on flow control Kr position, then check Ej (Kr) and if have the position of 1 to contain in Ej (Kr) position that arbitrary Ei all has 1, i < j, so Ej (Kr) just leaves out; If there is the position of 1 (-1) to have-1 (1) corresponding with co-located in Ej (Kr) at least in each Ei, i < j, illustrate that Ei and E (Kr) is non-intersect, then Ej (Kr) stays, it is the non-intersect subset changed, right also similar process is done.

(4) if Ej (Kr) does not leave out, also do not stay, then continue to decompose, in the minimal path sets Ljdis after non cross link, counter element is intact in 1, the element fault of-1 correspondence, and 0 represents not containing this element.

Obtain non-intersect minimal path matrix and non-intersect minimal path sets thus.Namely asked the reliably working probability RS of system in the accurate computing method of system reliability to be by minimal path sets:

$R_s=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}P\left\{L_{\mathrm{idis}}\right\}$ Formula 9

In formula, Lidis is i-th inconsistent minimal path sets.

Described cut set is the set be made up of arc in network S, if these arcs lost efficacy, then causes network S all to be lost efficacy by all paths of origin-to-destination, then claim the set of this group arc to be the cut set of network S.Be no longer just cut set remove any arc from cut set C after, then C is minimal cut set.

Refer to Fig. 1, point 1 to the minimal cut set C of point 4 is: C=x ₁x ₂+ x ₄x ₅+ x ₂x ₃x ₄+ x ₁x ₃x ₅formula 10.

Describedly ask the basic skills of minimal cut set to have the method for inversion and combined method by minimal path sets, the described method of inversion is according to De Morgan's theorem, is asked its inverting by the minimal path sets of network, can obtain the minimal cut set of network, has tried to achieve its minimal path sets to be

S=x ₁x ₄+ x ₂x ₅+ x ₁x ₃x ₅+ x ₂x ₃x ₄formula 5

Negate and drill:

$\begin{array}{c}\stackrel{\&OverBar;}{S}=\stackrel{\&OverBar;}{x_1{x}_4+x_2{x}_5+x_1{x}_3{x}_5+x_2{x}_3{x}_4}\\ =\stackrel{\&OverBar;}{x_1}\stackrel{\&OverBar;}{x_2}+\stackrel{\&OverBar;}{x_4}\stackrel{\&OverBar;}{x_5}+\stackrel{\&OverBar;}{x_2}\stackrel{\&OverBar;}{x_3}\stackrel{\&OverBar;}{x_4}+\stackrel{\&OverBar;}{x_1}\stackrel{\&OverBar;}{x_3}\stackrel{\&OverBar;}{x_5}\end{array}$ Formula 11

Thus, minimal cut set is: wherein, xi represents that element is normal, represent component failure.

Described combined method first writes out the minimal path sets matrix of network S.If a certain column element is all 1 in minimal path sets matrix, so, the element corresponding to matrix column is exactly the single order minimal cut set of network.Again two column elements any in minimal path sets matrix are carried out logical add combination, if the column element that after combination, certain two element is formed is all 1, so this two element is exactly a second order cut set of network.Then, then three elements are carried out logical add combination, if the column element that this element is formed is all 1, then this three element is three rank cut sets of network, and the rest may be inferred.

The top step number of described minimal cut set equals minimal path sets number, and after having obtained three rank to n rank cut set, must check out whether minimal cut set has been comprised in 2 to n-1 rank cut sets, if so, this cut set will be cast out as non-minimum cut set.

The minimal cut set of described system is

C=C ₁c ₂c _lformula 12

In general, Cj (j=1,2 ... l) comprise mutually, therefore asked by minimal cut set the failure probability Qs of system in the accurate computing method of System failure probability to be:

$\begin{array}{c}{Q}_S=P\left\{\begin{array}{cccc}{C}_1& C_2& ...& C_l\end{array}\right\}\\ =\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{C_i\right\}-\underset{i<j=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{\begin{array}{cc}{C}_i& C_j\end{array}\right\}+...\\ +{(-1)}^{l-1}P\left\{\begin{array}{ccc}{C}_1& C_2& C_l\end{array}\right\}\end{array}.$ Formula 13

In formula, Cj (j=1,2 ... l) be the cut set comprised mutually, the minimal cut set of system is C=C ₁c ₂c _l.

The minimal cut set intersected is adopted the method increasing argument, and change into disjoint minimal cut set one by one, it meets the following conditions:

$C_i_{i=1}^n=C_{\mathrm{jdis}}_{j=1}^m$ Formula 14

formula 15

Wherein represent n the minimal cut set intersected; represent m disjoint minimal cut set.

The described failure probability Qs of system in the approximate calculation method of System failure probability that asked by minimal cut set is:

$\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{C_i\right\}-\underset{i<j=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{\begin{array}{cc}{C}_i& C_j\end{array}\right\}\&le;Q_S\&le;\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{C_i\right\}$ Formula 16

In formula, for the upper bound of System failure probability Qs, for the lower bound of System failure probability Qs, when system scale is very large and element is a lot, often take this upper bound, road of thrashing as the approximate value of System failure probability Qs, to save computing time under the prerequisite ensureing engine request.

Refer to Fig. 3, in the described reliability calculation method coordinated mutually based on reliability and economy, the horizontal Rm of optimal reliability is the corresponding reliability level of reliability marginal cost when equaling reliability marginal contribution, the cost of investment that reliability marginal cost is increase unit reliability level and need increases, reliability marginal contribution is the benefit that obtains because adding a unit reliability level or the therefore outage cod reduced, therefore also can be described as marginal outage cost, known by reliability cost/performance analysis, when reliability marginal cost equals reliability marginal contribution, namely when cost of investment curve and reliability marginal outage cost curve intersection, for the Tm in figure, the lowest cost, at this moment corresponding reliability level Rm is optimal reliability level.If electric grid investment is not enough, if reliability cost corresponds to the A point on cost of investment curve, then corresponding power supply reliability level is R1, and lower than Rm, result causes outage cod to be B point on curve, and marginal total cost T1 is higher than Tm; If electric grid investment is too high, be set to the C point on outage cod curve, although the corresponding horizontal R2 of power supply reliability is higher than Rm, but cost of investment be increased to D point time, cause marginal total cost T2 still higher than Tm, therefore, only have the benefit when the cost of investment often increased needed for a unit power supply reliability level and user obtain because this reliability improves or the outage cod that reduces thus minimum time, electric network reliability level is only the most rational.

Described based in the electrical network otherness reliability calculation method of sensitivity, described sensitivity analysis is the impact that the subtle change of research component reliability parameter causes Reliability Index, reliability index is very large to the sensitivity of a certain device parameter, then this equipment is very large on the impact of system reliability, carrying out invest in the transformation of real estate to it can be just comparatively large to the raising of system reliability contribution, and described sensitivity analysis comprises element failure rate to the analysis of reliability effect and element repair time to the analysis of reliability effect.

Refer to Fig. 4, described power supply reliability index ASAI and the substantially linear variation tendency of element failure rate, as shown in table 1:

The relation of table 1 element failure rate and reliability index ASAI

Element failure rate (%)	0.6	0.8	1.0	1.2	1.4
						ASAI(％)	99.8488	99.8366	99.8228	99.8118	99.7997

Therefore, function admirable, high, the long-life equipment of reliability is adopted to be improve the effective means of available rate to reduce element failure rate.

Refer to Fig. 5, the analysis that described element affects available rate repair time, power supply reliability index ASAI and element fault substantially linear variation tendency repair time, as shown in table 2:

Table 2 element repair time and index ASAI relation table

Refer to Fig. 6, the failure rate of equipment is tub curve shape, and has three obvious regions, and region I is limber up period, and element failure rate declines in time gradually; Region II is the useful life phase, and element failure rate is close to constant; Region III is the attenuation phase, and element failure rate is in rising trend.Namely the ageing failure of element occurs in the attenuation phase, and the crash rate of ageing failure increases in time and increases in addition.

Refer to Fig. 7, the probability of element generation ageing failure is a conditional probability, T is the enlistment age of element, t be follow-up need consider preset time during, the definition of probability of element generation ageing failure is, point element be on active service T condition under, the indignant rate lost efficacy is there is in follow-up time t, element survival probability is defined as, point element be on active service T condition under, still keep the probability of service state to the T+t moment.

Refer to Fig. 8, the probability of element generation ageing failure and element survival probability WeibUll distribution are simulated, the crash rate of WeibUll distribution pattern statement and the relation between the time, consistent with consuming the situation of phase in the basin of component life shown in Fig. 6 paddy curve, corresponding to the curve of form parameter β > 1.

WeibUll distributed faults rate and accumulated probability distribution function are respectively:

${\mathrm{\&lambda;}}_a\left(t\right)=\frac{\mathrm{\&beta;}}{\mathrm{\&eta;}}{\left(\frac{t}{\mathrm{\&eta;}}\right)}^{\mathrm{\&beta;}-1}$ Formula 17

$F_a\left(t\right)=1-e^{-{\left(\frac{t}{\mathrm{\&eta;}}\right)}^{\mathrm{\&beta;}}}$ Formula 18

Wherein, t is the time, and β is form parameter, and η is that scale parameter also claims characteristics life parameter.

According to the definition of conditional probability, element is under arms after T time, and the probability that ageing failure occurs in its follow-up time interval Δ t is:

$P_a=\mathrm{Pr}(T\&le;t\&le;T+\mathrm{\&Delta;t}|t>T)=\frac{F_a(T+\mathrm{\&Delta;t})-F_a\left(T\right)}{1-F_a\left(T\right)}$ Formula 19

Will bring formula into, after the T time that obtained element under arms, the probability P a that ageing failure occurs in its follow-up time interval Δ t is:

$P_a=1-e^{{\left(\frac{T}{\mathrm{\&eta;}}\right)}^{\mathrm{\&beta;}}-{\left(\frac{T+\mathrm{\&Delta;t}}{\mathrm{\&eta;}}\right)}^{\mathrm{\&beta;}}}$ Formula 20

The present invention is on the basis of normal grid Calculation of Reliability, reliability and economy unification are considered and be applied in network operation, and establish the sensitivity index of reliability assessment, reliability and the unified consideration of economy both can be applied to line voltage hierarchical selection, electric network structure optimization, can be applicable to again the operation maintenance of electrical network, for network operation opens new road, solve and reliability can be made to bring up to the problem of how level under the condition of given investment, solve and how while reaching reliability requirement, the expenditure of construction of system to be reduced to minimum problem, solve the problem how making limited fund system reliability be reached optimum, solve in current electrical network and blindly increase investment, unlimited pursuit power supply reliability causes the problem of investment waste, the impact that the subtle change that sensitivity index studies component reliability parameter causes Reliability Index, the bottleneck of system for restricting reliability can be found exactly, the weak link increasing invest in the transformation of real estate is needed most in certainty annuity, can carry out on the basis of reliability cost/performance evaluation at the planning different to electrical network, optimization, modification scheme, determine optimum scheme.

Above the better embodiment of this patent is explained in detail, but this patent is not limited to above-mentioned embodiment, in the ken that one skilled in the relevant art possesses, various change can also be made under the prerequisite not departing from this patent aim.

Claims (4)

1. the computing method of a full voltage level Grid reliability, it is characterized in that, comprise normal grid reliability calculation method, the reliability calculation method coordinated mutually based on reliability and economy and the electrical network otherness reliability calculation method based on sensitivity, described normal grid reliability calculation method comprises the accurate computing method being asked system reliability by minimal path sets, ask the accurate computing method of System failure probability by minimal cut set and asked the approximate calculation method of System failure probability by minimal cut set, in the described reliability calculation method coordinated mutually based on reliability and economy, the horizontal Rm of optimal reliability is the corresponding reliability level of reliability marginal cost when equaling reliability marginal contribution, described based in the electrical network otherness reliability calculation method of sensitivity, element is under arms after T time, the probability P a that ageing failure occurs in its follow-up time interval Δ t is:

$P_a=1-e^{{\left(\frac{T}{\mathrm{\&eta;}}\right)}^{\mathrm{\&beta;}}-{\left(\frac{T+\mathrm{\&Delta;t}}{\mathrm{\&eta;}}\right)}^{\mathrm{\&beta;}}.}$

2. the computing method of full voltage level Grid reliability according to claim 1, is characterized in that, the described reliably working probability RS of system in the accurate computing method of system reliability that asked by minimal path sets is:

$R_s=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}P\left\{L_{\mathrm{idis}}\right\}.$

3. the computing method of full voltage level Grid reliability according to claim 1, is characterized in that, the described failure probability Qs of system in the accurate computing method of System failure probability that asked by minimal cut set is:

$\begin{array}{c}{Q}_s=P\left\{\begin{array}{cccc}{C}_1& C_2& \&CenterDot;\&CenterDot;\&CenterDot;& \end{array}{C}_l\right\}\\ =\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{C_i\right\}-\underset{i<j=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{\begin{array}{cc}{C}_i& C_j\end{array}\right\}+\&CenterDot;\&CenterDot;\&CenterDot;\\ +{(-1)}^{l-1}P\left\{\begin{array}{ccc}{C}_1& C_2& C_l\end{array}\right\}\end{array}.$

4. the computing method of full voltage level Grid reliability according to claim 1, is characterized in that, the described failure probability Qs of system in the approximate calculation method of System failure probability that asked by minimal cut set is:

$\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{C_i\right\}-\underset{i<j=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{\begin{array}{cc}{C}_i& C_j\end{array}\right\}\&le;Q_s\&le;\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}P\left\{C_i\right\}.$