Summary of the invention
For overcoming above-mentioned the deficiencies in the prior art, the present invention provides the cholesky of a kind of meter and interactive dependency to decompose half
Invariant tidal current computing method, on the basis of analyzing stochastic variable interactive response dependency, in conjunction with responsive node and random note
Enter correlation matrix computational methods between source node, it is proposed that the cumulant Probabilistic Load Flow modeling side decomposed based on cholesky
Method and calculation process.
Realizing the solution that above-mentioned purpose used is:
The cholesky of a kind of meter and interactive dependency decomposes cumulant tidal current computing method, described computational methods bag
Include:
(1) input basic data, node injecting power random distribution parameter and response participation factors;
(2) probability distribution and the response correlation matrix C of interactive response node injecting power are calculatedres;
(3) carry out Newton-Laphson method Load flow calculation at new benchmark operating point, obtain output variable node voltage X0With
Road power Z0And sensitivity matrix S0And T0;
(4) utilize cholesky decomposition method, the node injecting power stochastic variable with response dependency is converted to phase
The most independent stochastic variable;
(5) ask for meter and each rank cumulant of response dependency trend output variable, utilize Gram-Charlier progression
Calculate the probability distribution of output variable.
Preferably, in described step (1), branch parameters, generating needed for described basic data comprising determining that property Load flow calculation
Machine injecting power and load injecting power.
Preferably, in described step (1), described response participation factors such as following formula:
In formula: Δ PjmaxAdj sp for node;ΩRFor participating in the node set of interactive response, if certain node is connected to many
When platform unit or multiple flexible load, taking it and for the equivalent participation factors of this node, all node participation factors sums are 1, j
For jth node.
Preferably, in described step (2), described calculating includes:
(2-1) meter and stochastic source inject node new forms of energy randomness and load prediction randomness, obtain system imbalance merit
Rate;
(2-2) obtained the sample of each random node injecting power by Monte Carlo sampling method, use correlation coefficient ρijRetouch
State the response randomness Δ P ' of interactive response node jresjWith the randomness Δ P that stochastic source injects node iiLinear correlation degree;
(2-3) obtain n stochastic source and inject node i, the correlation matrix C of m interactive response node j randomnessres,
Matrix is that (m+n) ties up symmetrical matrix.
Further, in described step (2-1), described system imbalance power such as following formula:
Punb=Punb0+ΔPunb
In formula: PunbFor system imbalance power;Punb0For the definitiveness part in imbalance power;ΔPunbFor randomness
Part;ΩIRepresent that stochastic source injects the set of node;ΔPiFor the randomness of node i injecting power, this node connected new energy
Source randomness Δ PwiWith load randomness Δ PliJointly cause.
Further, in described step (2-2), described correlation coefficient ρijSuch as following formula:
Wherein, cov () is covariance, and D () is variance.
Preferably, in described step (3), system load flow equation matrix form is as follows:
Wherein, X, Z represent that node voltage and branch power, subscript 0 represent benchmark running status respectively;Δ x, Δ z are respectively
Represent node voltage and the change at random amount of branch power;Δ w represents the change at random amount of injecting power;S0With T0Represent respectively
The sensitivity that injecting power is changed by node voltage and branch power.
Preferably, in described step (4), described decomposition such as following formula:
Cres=GGT
In formula: G is lower triangular matrix, GTTransposition for G.
Preferably, in described step (5), described each rank cumulant such as following formula:
In formula: (*)(k)Represent k rank cumulant;After considering response dependency, Δ w carrying out piecemeal, Δ w ' is the most solely
Vertical input variable, Δ w is " for having the input variable of response dependency;G is correlation matrix CresDivided by cholesky
Lower triangular matrix after solution;A is diagonal matrix, and diagonal element is the standard deviation of node injecting power relevant variable;Δ Y be standard just
State be distributed, its single order cumulant is 0, and second order cumulant is 1, three rank and above be 0;S′0Represent separate node
The sensitivity matrix block that injecting power is changed by voltage, S "0Represent that the node voltage with response dependency is to injecting power
Sensitivity matrix block, T '0Represent the separate node branch power sensitivity matrix block to injecting power, T "0Expression has
The node branch power of the response dependency sensitivity matrix block to injecting power.
Compared with prior art, the method have the advantages that
The present invention devises the cholesky of a kind of meter and interactive dependency and decomposes cumulant tidal current computing method, the party
Method can be counted and the uncertainty of flexible load interactive response behavior, and simulation calculated load participate in the randomness of scheduling, and utilize
Cholesky decomposition method solves interactive response dependency.The present invention be conducive to improving under strong uncertain environment electric network swim analysis and
Computing capability, is particularly suited for flexible load and can participate in the actual fortune of system call post analysis electrical network by resource response as a kind of high-quality
Market condition, promotes the electrical network receiving ability to new forms of energy further.
Detailed description of the invention
Below in conjunction with the accompanying drawings the detailed description of the invention of the present invention is described in further detail.
1, input basis flow data, probability distribution parameters and response regulation coefficient.Basic data includes definitiveness trend
Calculate required branch parameters, electromotor and load injecting power etc., additionally need input node injecting power random distribution parameter,
Response participation factors etc..
When in system, some bus nodes accesses certain adjustable unit or flexible load, its scheduling quantum can be as balance
The interactive response amount of system imbalance power, these bus nodes are referred to as interactive response node.Can be according to the connected unit of node
Or the regulations speed (or variable capacity etc.) of flexible load determines its participation factors, with unit (or flexible load) creep speed
As a example by being directly proportional, the response participation factors of node j is represented by:
In formula: Δ PjmaxAdj sp for node;ΩRFor participating in the node set of interactive response, if certain node is connected to many
During platform unit (or multiple flexible load), taking it and for the equivalent participation factors of this node, all node participation factors sums are
1。
2, according to the imbalance power of system, use and calculate interactive response node injecting power based on monte carlo method
Probability distribution and response correlation matrix Cres。
For certain electrical network, after counting and injecting node new forms of energy randomness and load prediction randomness, system imbalance power
Also it is a stochastic variable, is represented by:
Punb=Punb0+ΔPunb (2)
In formula: PunbFor system imbalance power;Punb0For the definitiveness part in imbalance power;ΔPunbFor randomness
Part;ΩIRepresent that stochastic source injects the set of node;ΔPiRandomness for node i injecting power;New energy is connected by this node
Source randomness Δ PwiWith load randomness Δ PliJointly cause.
Then system imbalance power expectation part and randomness part Δ PunbAll according to participation factors K on node jjEnter
Row distribution, can be obtained the random partial Δ P of node j interactive response amount by formula (3)resjIt is represented by:
Assume interactive node response quautity also Normal Distribution, the then random distribution of system imbalance power and interactive node
The random distribution relation of response quautity is as shown in schematic diagram 2.It is to say, when system imbalance power is Δ P1Time, interactive node j
Response quautity expected value be KjΔP1, owing to considering that response self randomness then response quautity is obeyedNormal distribution,
Consider that interactive response self randomness posterior nodal point interactive response amount is denoted as Δ P 'resj。
Additionally, according to formula (4) it is seen that, the response randomness Δ P ' of interactive node jresjNode is injected with stochastic source
The randomness Δ P of iiThere is obvious dependency relation.The sample of each random node injecting power is obtained by Monte Carlo sampling method
This, use correlation coefficient ρ on this basisijLinear correlation degree between the two described:
In formula: cov () is covariance, D () is variance.
Thus, available stochastic source injects node i (n altogether), the phase relation of interactive response node j (m altogether) randomness
Matrix number Cres, matrix is (m+n) dimension symmetrical matrix:
3, carry out Newton-Laphson method Load flow calculation at new benchmark operating point, obtain output variable node voltage X and branch road
Trend Z and sensitivity matrix S0And T0.When the expected value of system imbalance power is shared by responsive node according to participation factors
After obtain the benchmark operating point that system is new, then system load flow equation matrix form is as follows:
Wherein, X, Z represent that node voltage and branch power, subscript 0 represent benchmark running status respectively;Δ x, Δ z are respectively
Represent node voltage and the change at random amount of branch power;Δ w represents the change at random amount of injecting power;S0With T0Represent respectively
The sensitivity that injecting power is changed by node voltage and branch power.
4, utilize Cholesky decomposition method, the node injecting power stochastic variable with response dependency is converted to mutually
Independent stochastic variable.
Correlation matrix CresGenerally positive definite matrix, then can carry out cholesky decomposition to this matrix:
Cres=GGT (8)
In formula: G is lower triangular matrix, its element is represented by:
In formula: ρkkAnd ρlkIt is respectively correlation matrix CresIn correlation coefficient;K is to have relevant stochastic variable
Number, is m+n herein.If random node and the injecting power of interactive response nodeClothes
From normal distribution, orderX is the stochastic variable of one group of obedience standard normal distribution, and its correlation matrix is still
Cres;A is diagonal matrix, and diagonal element is the standard deviation of node injecting power relevant variable;μ is its expectation.
Correlation matrix C is understood by formula (9)resFor symmetrical matrix, then there is an orthogonal matrix B, can will have dependency
Stochastic variable X be converted into the stochastic variable Y of incoherent obedience standard normal distribution:
Y=BX (10)
In formula: Y=[y1,y2,…,yn+m]TIt is one group of separate stochastic variable obeying standard normal distribution, then
The correlation matrix C of YYFor unit matrix I, thus can obtain:
Take B=G-1, i.e. Y=G-1X, can have one group of stochastic variable of dependencyIt is expressed as incoherent obedience to mark
The expression formula of quasi normal distribution stochastic variable Y:
5, ask for meter and each rank cumulant of response dependency trend output variable, utilize Gram-Charlier progression
Calculate the probability distribution of output variable.After system node injecting power random partial after meter and response, calculate system load flow defeated
The each rank cumulant going out variable is represented by:
After considering response dependency, Δ w is carried out piecemeal, it may be assumed that
" for there is the input variable of response dependency, on the other hand in formula: Δ w ' is separate input variable, Δ w
The S answered0, T0Also piecemeal is:
By Cholesky decomposition method, the input variable with response dependency is converted into separate standard normal
Distribution, hereinI.e. Δ w "=AG Δ Y, shown under the form that formula (13) is final:
In formula: (*)(k)Represent k rank cumulant;After considering response dependency, Δ w carrying out piecemeal, Δ w ' is the most solely
Vertical input variable, Δ w is " for having the input variable of response dependency;G is correlation matrix CresDivided by cholesky
Lower triangular matrix after solution;A is diagonal matrix, and diagonal element is the standard deviation of node injecting power relevant variable;Δ Y be standard just
State be distributed, its single order cumulant is 0, and second order cumulant is 1, three rank and above be 0;S′0Represent separate node
The sensitivity matrix block that injecting power is changed by voltage, S "0Represent that the node voltage with response dependency is to injecting power
Sensitivity matrix block, T '0Represent the separate node branch power sensitivity matrix block to injecting power, T "0Expression has
The node branch power of the response dependency sensitivity matrix block to injecting power.
On this basis, Gram-Charlier progression is utilized to calculate output variable probability distribution.
Finally should be noted that: above example is merely to illustrate the technical scheme of the application rather than to its protection domain
Restriction, although being described in detail the application with reference to above-described embodiment, those of ordinary skill in the field should
Understand: those skilled in the art read the application after still can to application detailed description of the invention carry out all changes, amendment or
Person's equivalent, but these changes, amendment or equivalent, all within the claims that application is awaited the reply.