CN103269069B - A kind of method of low voltage power transmission grid reconstruct - Google Patents

Abstract

The invention provides the method for a kind of low voltage power transmission grid reconstruct, comprising: step S1, from the EMS of control centre, obtain electric network model and the data section of transmission system; Step S2, calculates the power loss sensitivity of each node in electric network model, and the power loss sensitivity of node is that node is gained merit the proportionate relationship that the increase of exerting oneself and the total active loss of system increase; Step S3, calculates any one substation according to the power loss sensitivity of node and switches the network loss change after supply terminals, filter out the supply terminals that network loss can be made to reduce and switch reconstruction strategy, obtain the reconfiguration scheme of low voltage power transmission system; Step S4, carries out safety check to reconfiguration scheme, judges to adjust reconfiguration scheme when having newly-increased equipment out-of-limit.The method of a kind of low voltage power transmission grid reconstruct provided by the invention, based on power loss sensitivity, filters out the supply terminals that network loss can be made to reduce according to power loss sensitivity and switches reconstruction strategy.

Description

A kind of method of low voltage power transmission grid reconstruct

Technical field

The present invention relates to power system computation field, be specifically related to the method for a kind of low voltage power transmission grid reconstruct.

Background technology

At present, power industry has become the important industry of countries in the world, and for entire society provides the required energy and power, through-put power is huge.Electric power system realizes electrical network to carrying to the electric flux of user by links such as the transmission of electricity in electric power networks, power transformation and distribution, due to the existence of power system impedance, electric energy conversion, conveying, in assigning process inevitably along with a large amount of losses, and to be dissipated in surrounding medium with forms such as heat energy.

Day by day perfect along with power system operation and management, Network Loss Rate has become the important technology economic index weighed and examine power supply enterprise's production and operation, it can reflect the planning and designing of electrical network, manufacture the height of production technology and Marketing management level, is directly connected to the economic benefit of electric power enterprise.Reducing Network Loss Rate is one of economic benefit important means improving power supply enterprise.

In fact, low voltage power transmission system losses are important component parts of regional network loss, account for more than 60% of total network loss, and visible reduction low voltage power transmission system losses are the keys of falling damage work.

Summary of the invention

The present invention relates to the method for a kind of low voltage power transmission grid reconstruct, comprising: step S1, from the EMS of control centre, obtain electric network model and the data section of described transmission system;

Step S2, calculates the power loss sensitivity of each node in described electric network model, and the power loss sensitivity of described node is that node is gained merit the proportionate relationship that the increase of exerting oneself and the total active loss of transmission system increase;

Step S3, calculates any one substation according to the power loss sensitivity of described node and switches the network loss change after supply terminals, filter out the supply terminals that network loss can be made to reduce and switch reconstruction strategy, obtain the reconfiguration scheme of described low voltage power transmission system;

Step S4, carries out safety check to described reconfiguration scheme, judges to adjust described reconfiguration scheme when having newly-increased equipment out-of-limit.

In first preferred embodiment provided by the invention: in described step S1, what obtain from the EMS of described control centre is real-time or the electric network model of described transmission system and data section under research mode, comprises the data of device parameter, equipment operational mode and measurement.

In second preferred embodiment provided by the invention: the method calculating the power loss sensitivity of arbitrary node i in described electric network model in described step S2 comprises:

Step S201, lists the matrix form of Load flow calculation formula according to electric network model and operational mode:

$\left[\begin{array}{c}{\mathrm{\ΔP}}_1\\ {\mathrm{\ΔP}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔP}}_N\\ {\mathrm{\ΔQ}}_1\\ {\mathrm{\ΔQ}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔQ}}_N\end{array}\right]=\left[\begin{array}{cccccccc}\frac{{\∂P}_1}{{\∂\mathrm{\θ}}_1}& \frac{{\∂P}_1}{{\∂\mathrm{\θ}}_2}& ...& \frac{{\∂P}_1}{{\∂\mathrm{\θ}}_N}& \frac{{\∂P}_1}{{\∂V}_1}& \frac{{\∂P}_1}{{\∂V}_2}& ...& \frac{{\∂P}_1}{{\∂V}_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ \frac{{\∂P}_N}{{\∂\mathrm{\θ}}_1}& \frac{{\∂P}_N}{{\∂\mathrm{\θ}}_2}& ...& \frac{{\∂P}_N}{{\∂\mathrm{\θ}}_N}& \frac{{\∂P}_N}{{\∂V}_1}& \frac{{\∂P}_N}{{\∂V}_2}& ...& \frac{{\∂P}_N}{{\∂V}_N}\\ \frac{{\∂Q}_1}{{\∂\mathrm{\θ}}_1}& \frac{\∂Q_1}{{\∂\mathrm{\θ}}_2}& ...& \frac{{\∂Q}_1}{{\∂\mathrm{\θ}}_N}& \frac{{\∂Q}_1}{\∂V_1}& \frac{{\∂Q}_1}{{\∂V}_2}& ...& \frac{{\∂Q}_1}{{\∂V}_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ \frac{{\∂Q}_N}{{\∂\mathrm{\θ}}_1}& \frac{{\∂Q}_N}{{\∂\mathrm{\θ}}_2}& ...& \frac{{\∂Q}_N}{{\∂\mathrm{\θ}}_N}& \frac{{\∂Q}_N}{{\∂V}_1}& \frac{{\∂Q}_N}{{\∂V}_2}& ...& \frac{{\∂Q}_N}{{\∂V}_N}\end{array}\right]\left[\begin{array}{c}{\mathrm{\Δ\θ}}_1\\ {\mathrm{\Δ\θ}}_2\\ .\\ .\\ .\\ {\mathrm{\Δ\θ}}_N\\ {\mathrm{\ΔV}}_1\\ {\mathrm{\ΔV}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔV}}_N\end{array}\right]=J\left[\begin{array}{c}{\mathrm{\Δ\θ}}_1\\ {\mathrm{\Δ\θ}}_2\\ .\\ .\\ .\\ {\mathrm{\Δ\θ}}_N\\ {\mathrm{\ΔV}}_1\\ {\mathrm{\ΔV}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔV}}_N\end{array}\right]$

In formula, V ₁-V _nand θ ₁-θ _nbe respectively each node voltage amplitude vector sum angle, P ₁-P _nand Q ₁-Q _nbe respectively that each node is meritorious, idle injection, J is coefficient matrix brief note form, obtains matrix J conversion of inverting:

$\left[\begin{array}{c}{\mathrm{\Δ\θ}}_1\\ {\mathrm{\Δ\θ}}_2\\ .\\ .\\ .\\ {\mathrm{\Δ\θ}}_N\\ {\mathrm{\ΔV}}_1\\ {\mathrm{\ΔV}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔV}}_N\end{array}\right]=J^{-1}\left[\begin{array}{c}{\mathrm{\ΔP}}_1\\ \mathrm{\Δ}{P}_2\\ .\\ .\\ .\\ \mathrm{\Δ}{P}_N\\ \mathrm{\Δ}{Q}_1\\ \mathrm{\Δ}{Q}_2\\ .\\ .\\ .\\ \mathrm{\Δ}{Q}_N\end{array}\right]=\left[\begin{array}{cccccccc}\frac{{\∂\mathrm{\θ}}_1}{\∂P_1}& \frac{{\∂\mathrm{\θ}}_1}{\∂P_2}& ...& \frac{{\∂\mathrm{\θ}}_1}{{\∂P}_N}& \frac{{\∂\mathrm{\θ}}_1}{\∂Q_1}& \frac{{\∂\mathrm{\θ}}_1}{\∂Q_2}& ...& \frac{{\∂\mathrm{\θ}}_1}{\∂Q_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& ..& .\\ \frac{{\∂\mathrm{\θ}}_N}{\∂P_1}& \frac{{\∂\mathrm{\θ}}_N}{\∂P_2}& ...& \frac{{\∂\mathrm{\θ}}_N}{\∂P_N}& \frac{{\∂\mathrm{\θ}}_N}{\∂Q_1}& \frac{{\∂\mathrm{\θ}}_N}{\∂Q_2}& ...& \frac{{\∂\mathrm{\θ}}_N}{\∂Q_N}\\ \frac{{\∂V}_1}{\∂P_1}& \frac{\∂V_1}{\∂P_2}& ...& \frac{{\∂V}_1}{\∂P_N}& \frac{{\∂V}_1}{\∂P_1}& \frac{{\∂V}_1}{\∂P_2}& ...& \frac{{\∂V}_1}{\∂P_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ \frac{\∂V_N}{{\∂P}_1}& \frac{\∂V_N}{{\∂P}_2}& ...& \frac{{\∂V}_N}{{\∂P}_N}& \frac{{\∂V}_N}{{\∂Q}_1}& \frac{{\∂V}_N}{{\∂Q}_2}& ...& \frac{{\∂V}_N}{{\∂Q}_N}\end{array}\right]\left[\begin{array}{c}{\mathrm{\ΔP}}_1\\ {\mathrm{\ΔP}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔP}}_N\\ {\mathrm{\ΔQ}}_1\\ {\mathrm{\ΔQ}}_2\\ \text{.}\\ .\\ .\\ {\mathrm{\ΔQ}}_N\end{array}\right]$

J ^-1the influence degree that matrix has reacted described transmission system interior joint voltage magnitude, angle changes by node injecting power each in described transmission system: each element in matrix is the number ratios relation of voltage magnitude, angle variable quantity and each node injecting power variable quantity in corresponding node represent when the meritorious injection of increase by 1 unit on node k respectively, the variable quantity of voltage magnitude, phase angle on node t;

Step S202, theoretical according to tandem circuit, described transmission system network total losses computing formula of gaining merit is:

$P_L=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{G}_{\mathrm{ij}}{V}_i{V}_j{\cos \mathrm{\θ}}_{\mathrm{ij}}$

In formula, P _lfor the total network loss of described transmission system, N is the total nodes of described transmission system, G _ijfor the real part of the transadmittance between node i, j, V _i, V _jfor the voltage magnitude of node i and j, θ _ijfor the phase angle difference between nodes i, j, θ _ifor the phase angle of node i; By line losses management formula, try to achieve the impact that the total network loss of described transmission system is subject to any node t voltage magnitude and phase angle change: with

Step S203, calculates according to described step S201 and step S202 trying to achieve the meritorious injection sensitivity of described transmission system network loss to a node k any in described transmission system is: $S_k=\frac{{\∂P}_L}{{\∂P}_k}=\underset{t=1}{\overset{N}{\mathrm{\Σ}}}(\frac{{\∂P}_L}{{\∂\mathrm{\θ}}_t}\frac{{\∂\mathrm{\θ}}_t}{{\∂P}_k}+\frac{{\∂P}_L}{{\∂V}_t}\frac{{\∂V}_t}{{\∂P}_k}).$

In 3rd preferred embodiment provided by the invention: in described step S3 according to the power loss sensitivity of described node calculate any one substation by supply power mode from A point power switching for from B point power, network loss changes delta Loss _aBsize is: Δ Loss _aB=(S _b-S _a) P _d+ P _lB;

Wherein, S _bfor the meritorious injection sensitivity of Node B, S _afor the meritorious injection sensitivity of Node B, P _dfor described substation is gained merit total load, P _lBfor the active loss on transmission line between described Node B to low pressure dependent station and: $P_{\mathrm{LB}}=\frac{{P_d}^2+{Q_d}^2}{{U_B}^2}{R}_B;$

Wherein, Q _dfor the idle total load of voltage dependent station, U _bfor node B voltage amplitude, R _bfor the resistance of circuit between this substation to Node B.

In 4th preferred embodiment provided by the invention: after filtering out the reconstruction strategy of the supply terminals switching that network loss can be made to reduce in described step S3, filter out the scheme reducing described transmission system network loss, after excluding the actual reconstruction strategy that cannot operate, obtain the reconfiguration scheme of described low voltage power transmission system.

In 5th preferred embodiment provided by the invention: the described actual reconstruction strategy that cannot operate comprise turn power supply across 500kV great Qu and cyclization point phase difference excessive.

In 6th preferred embodiment provided by the invention: the mode by Load flow calculation in described step S4 checks with or without newly added equipment out-of-limit;

Judge to adjust reconfiguration scheme when having newly-increased equipment out-of-limit, adjustable strategies gains merit to gain merit to node according to branch road to inject the size of sensitivity and formulate, according to the out-of-limit degree of described branch road, gain merit to gain merit to the different nodes on described branch road according to described branch road and inject the difference of size of sensitivity, select the different reconstruction strategy of the different nodes cancelling the described branch road of impact.

In 7th preferred embodiment provided by the invention: in described step S4, supply power mode is cause branch road l changed power to be from the impact of reconstruction strategy on described branch power of B point power supply from A point power switching by described substation: Δ P _l=(S _l,B-S _l,A) P _d;

Wherein, Δ P _lfor branch road l power variation, S _l,A, S _l,Bbe respectively branch road l meritorious to node A and B meritorious injection sensitivity.

In 8th preferred embodiment provided by the invention: two end nodes are the branch road l of i and j, calculate described branch road l meritorious to arbitrary node k meritorious injection sensitivity S _l,kmethod comprise:

Step S401, according to the meritorious equation P in DC power flow method for simplifying _l=B _l(θ _i-θ _j) obtain branch power increment Delta P _lbe expressed as: Δ P _l=B _lΔ θ _i-B _lΔ θ _j;

Wherein, P _lfor flowing through the active power of branch road l, B _lfor branch road l susceptance, θ _i, θ _jfor the voltage phase angle of branch road l two ends node i and j, Δ θ _i, Δ θ _jfor the voltage phase angle increment of branch road l two ends node i and j.

Step S402, can be obtained by PQ decoupling method Load flow calculation equation: [Δ θ]=[B'] ^-1[Δ P];

Wherein, [Δ θ] and [Δ P] is respectively node voltage phase angle increment and node meritorious injection incremental vector, [B'] to gain merit the coefficient matrix of iterative equation formula for quick decoupling method, by described PQ decoupling method Load flow calculation equation calculate arbitrary node voltage phase angle by node each in system gain merit inject change influence degree, note node i, the phase angle increment of j and the node k proportionate relationship injected of gaining merit is $S_{\mathrm{\θi},k}=\frac{{\∂\mathrm{\θ}}_i}{{\∂P}_k},$ $S_{\mathrm{\θj},k}=\frac{{\∂\mathrm{\θ}}_j}{{\∂P}_k};$

Step S403, the power calculating branch road l power increment and node k according to step S401 injects the proportionate relationship Δ P of increment _l=B _l(S _{θ i, k}-S _{θ j, k}) Δ P _k, namely branch road l gains merit to the meritorious injection sensitivity S of node k _l,kfor: S _l,k=B _l(S _{θ i, k}-S _{θ j, k}).

The beneficial effect of the method for a kind of low voltage power transmission grid reconstruct provided by the invention comprises:

1, the method of a kind of low voltage power transmission grid reconstruct provided by the invention is based on power loss sensitivity, 110kV and following low voltage electric network generally follow closed loop design, open loop operation principle, under normal conditions, low pressure receiving and transforming station is powered by a power supply point, but the power supply 220kV and the above transformer station that in fact can be its power supply may have multiple, the method of a kind of network reconfiguration provided by the invention is in units of substation, judge that current substation is the need of reconstruct according to power loss sensitivity, filter out the supply terminals that network loss can be made to reduce and switch reconstruction strategy, can when not increasing investment with construction, by changing network frame topology structure, digging system potentiality, reduce system power dissipation, improve the economy of system cloud gray model, based on power loss sensitivity, explicit physical meaning, solve convenient and swift, the basis of the network topology structure of current system is finely tuned, the number of switches of participant status adjustment is few, thus result of calculation is workable, can guidance system actual motion, the economy of practical raising system cloud gray model.

2, after filtering out the supply terminals switching reconstruction strategy that network loss can be made to reduce, various logic can be used to screen reconfiguration scheme, as whether turned power supply across 500kV great Qu, whether cyclization point phase difference is excessive, remove infeasible reconstruction strategy, simplify computational process, screening process adopts open by design, and screening logic can expand in actual use flexibly.

3, use sensitivity method to adjust the reconfiguration scheme obtained, eliminate newly-increased out-of-limit, improve the feasibility of reconfiguration scheme.In the process that elimination is out-of-limit, considering the power loss sensitivity of reconstruction strategy and the sensitivity to branch power, not causing on newly-increased out-of-limit basis, reducing system losses as much as possible, improve the economy of system cloud gray model.

Accompanying drawing explanation

Be illustrated in figure 1 the flow chart of the method for a kind of low voltage power transmission grid reconstruct provided by the invention;

Be illustrated in figure 2 the schematic diagram of the powered embodiment of a kind of substation provided by the invention.

Embodiment

With reference to the accompanying drawings the specific embodiment of the present invention is described in further detail below.

The invention provides the method for a kind of low voltage power transmission grid reconstruct, its flow chart as shown in Figure 1, comprising:

Step S1, obtains electric network model and the data section of transmission system from the EMS of control centre.

Step S2, calculates the power loss sensitivity of each node in electric network model, and wherein, the power loss sensitivity of node is that node is gained merit the proportionate relationship that the increase of exerting oneself and the total active loss of system increase.

Step S3, calculates any one substation according to the power loss sensitivity of node and switches the network loss change after supply terminals, filter out the supply terminals that network loss can be made to reduce and switch reconstruction strategy, obtain the reconfiguration scheme of this low voltage power transmission system.

Step S4, carries out safety check to reconfiguration scheme, judges to adjust reconfiguration scheme when having newly-increased equipment out-of-limit.

In step S1, what obtain from the EMS of control centre is real-time or the electric network model of transmission system and data section under research mode, comprises the data such as device parameter, equipment operational mode and measurement.

Need in step S2 to calculate the power loss sensitivity of each node in electric network model according to the electric network model obtained and data section, existing power loss sensitivity computational methods are a lot, as transposition Jacobi matrix method, B Y-factor method Y, the Impedance Moment tactical deployment of troops, admittance matrix algorithm etc., comparatively accurate and ripe transposition Jacobi matrix method can be adopted to calculate.The power loss sensitivity S of arbitrary node i in electric network model is calculated in a kind of step S2 provided by the invention _ithe embodiment of method be:

Step S201, can list the matrix form of Load flow calculation formula according to electric network model and operational mode:

$\left[\begin{array}{c}{\mathrm{\ΔP}}_1\\ {\mathrm{\ΔP}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔP}}_N\\ {\mathrm{\ΔQ}}_1\\ {\mathrm{\ΔQ}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔQ}}_N\end{array}\right]=\left[\begin{array}{cccccccc}\frac{{\∂P}_1}{{\∂\mathrm{\θ}}_1}& \frac{{\∂P}_1}{{\∂\mathrm{\θ}}_2}& ...& \frac{{\∂P}_1}{{\∂\mathrm{\θ}}_N}& \frac{{\∂P}_1}{{\∂V}_1}& \frac{{\∂P}_1}{{\∂V}_2}& ...& \frac{{\∂P}_1}{{\∂V}_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ \frac{{\∂P}_N}{{\∂\mathrm{\θ}}_1}& \frac{{\∂P}_N}{{\∂\mathrm{\θ}}_2}& ...& \frac{{\∂P}_N}{{\∂\mathrm{\θ}}_N}& \frac{{\∂P}_N}{{\∂V}_1}& \frac{{\∂P}_N}{{\∂V}_2}& ...& \frac{{\∂P}_N}{{\∂V}_N}\\ \frac{{\∂Q}_1}{{\∂\mathrm{\θ}}_1}& \frac{\∂Q_1}{{\∂\mathrm{\θ}}_2}& ...& \frac{{\∂Q}_1}{{\∂\mathrm{\θ}}_N}& \frac{{\∂Q}_1}{\∂V_1}& \frac{{\∂Q}_1}{{\∂V}_2}& ...& \frac{{\∂Q}_1}{{\∂V}_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ \frac{{\∂Q}_N}{{\∂\mathrm{\θ}}_1}& \frac{{\∂Q}_N}{{\∂\mathrm{\θ}}_2}& ...& \frac{{\∂Q}_N}{{\∂\mathrm{\θ}}_N}& \frac{{\∂Q}_N}{{\∂V}_1}& \frac{{\∂Q}_N}{{\∂V}_2}& ...& \frac{{\∂Q}_N}{{\∂V}_N}\end{array}\right]\left[\begin{array}{c}{\mathrm{\Δ\θ}}_1\\ {\mathrm{\Δ\θ}}_2\\ .\\ .\\ .\\ {\mathrm{\Δ\θ}}_N\\ {\mathrm{\ΔV}}_1\\ {\mathrm{\ΔV}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔV}}_N\end{array}\right]=J\left[\begin{array}{c}{\mathrm{\Δ\θ}}_1\\ {\mathrm{\Δ\θ}}_2\\ .\\ .\\ .\\ {\mathrm{\Δ\θ}}_N\\ {\mathrm{\ΔV}}_1\\ {\mathrm{\ΔV}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔV}}_N\end{array}\right]$

In formula, V ₁-V _nand θ ₁-θ _nbe respectively each node voltage amplitude vector sum angle, P ₁-P _nand Q ₁-Q _nbe respectively that each node is meritorious, idle injection, J is coefficient matrix brief note form, obtains matrix J conversion of inverting:

$\left[\begin{array}{c}{\mathrm{\Δ\θ}}_1\\ {\mathrm{\Δ\θ}}_2\\ .\\ .\\ .\\ {\mathrm{\Δ\θ}}_N\\ {\mathrm{\ΔV}}_1\\ {\mathrm{\ΔV}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔV}}_N\end{array}\right]=J^{-1}\left[\begin{array}{c}{\mathrm{\ΔP}}_1\\ \mathrm{\Δ}{P}_2\\ .\\ .\\ .\\ \mathrm{\Δ}{P}_N\\ \mathrm{\Δ}{Q}_1\\ \mathrm{\Δ}{Q}_2\\ .\\ .\\ .\\ \mathrm{\Δ}{Q}_N\end{array}\right]=\left[\begin{array}{cccccccc}\frac{{\∂\mathrm{\θ}}_1}{\∂P_1}& \frac{{\∂\mathrm{\θ}}_1}{\∂P_2}& ...& \frac{{\∂\mathrm{\θ}}_1}{{\∂P}_N}& \frac{{\∂\mathrm{\θ}}_1}{\∂Q_1}& \frac{{\∂\mathrm{\θ}}_1}{\∂Q_2}& ...& \frac{{\∂\mathrm{\θ}}_1}{\∂Q_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& ..& .\\ \frac{{\∂\mathrm{\θ}}_N}{\∂P_1}& \frac{{\∂\mathrm{\θ}}_N}{\∂P_2}& ...& \frac{{\∂\mathrm{\θ}}_N}{\∂P_N}& \frac{{\∂\mathrm{\θ}}_N}{\∂Q_1}& \frac{{\∂\mathrm{\θ}}_N}{\∂Q_2}& ...& \frac{{\∂\mathrm{\θ}}_N}{\∂Q_N}\\ \frac{{\∂V}_1}{\∂P_1}& \frac{\∂V_1}{\∂P_2}& ...& \frac{{\∂V}_1}{\∂P_N}& \frac{{\∂V}_1}{\∂P_1}& \frac{{\∂V}_1}{\∂P_2}& ...& \frac{{\∂V}_1}{\∂P_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ \frac{\∂V_N}{{\∂P}_1}& \frac{\∂V_N}{{\∂P}_2}& ...& \frac{{\∂V}_N}{{\∂P}_N}& \frac{{\∂V}_N}{{\∂Q}_1}& \frac{{\∂V}_N}{{\∂Q}_2}& ...& \frac{{\∂V}_N}{{\∂Q}_N}\end{array}\right]\left[\begin{array}{c}{\mathrm{\ΔP}}_1\\ {\mathrm{\ΔP}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔP}}_N\\ {\mathrm{\ΔQ}}_1\\ {\mathrm{\ΔQ}}_2\\ \text{.}\\ .\\ .\\ {\mathrm{\ΔQ}}_N\end{array}\right]$

Described by above formula, J ^-1the influence degree that matrix has reacted system interior joint voltage magnitude, angle changes by node injecting power each in system: each element in matrix is the number ratios relation of voltage magnitude, angle variable quantity and each node injecting power variable quantity in corresponding node.As represent when the meritorious injection of increase by 1 unit on node k respectively, the variable quantity of voltage magnitude, phase angle on node t.

Step S202, theoretical according to tandem circuit, transmission system network total losses computing formula of gaining merit can be expressed as:

$P_L=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{G}_{\mathrm{ij}}{V}_i{V}_j{\cos \mathrm{\θ}}_{\mathrm{ij}}$

In formula, P _lfor the total network loss of system, N is the total nodes of system, G _ijfor the real part of the transadmittance between node i, j, V _i, V _jfor the voltage magnitude of node i and j, θ _ijfor the phase angle difference between nodes i, j, θ _ifor the phase angle of node i.To be gained merit total losses computing formula by this network, the impact of the total network loss of system by any node t voltage magnitude and phase angle change can be tried to achieve: with

Step S203, calculates according to described step S201 and step S202 trying to achieve the meritorious injection sensitivity of transmission system network loss to a node k any in this transmission system is: $S_k=\frac{{\∂P}_L}{{\∂P}_k}=\underset{t=1}{\overset{N}{\mathrm{\Σ}}}(\frac{{\∂P}_L}{{\∂\mathrm{\θ}}_t}\frac{{\∂\mathrm{\θ}}_t}{{\∂P}_k}+\frac{{\∂P}_L}{{\∂V}_t}\frac{{\∂V}_t}{{\∂P}_k})$

Be illustrated in figure 2 the schematic diagram that the powered embodiment of a kind of substation provided is provided, as shown in Figure 2, this substation now by high voltage power transmisson system node A be its power supply, consider for raising power supply reliability, grid can also change by Node B as this dependent station is powered by changing related switch running status.

R in Fig. 2 _b+ jX _bfor B point is to the connecting line resistance value of dependent station.Because A, B 2 are positioned at the diverse location of high voltage power transmisson system, its power loss sensitivity size is also variant, is designated as S respectively _a, S _b.

Step S3 mesolow transformer station by supply power mode from A point power switching be from B point power supply, network loss changes delta Loss _aBsize is:

ΔLoss _AB＝(S _B-S _A)P _d+P _LB(5)

Wherein, S _bfor the meritorious injection sensitivity of Node B, S _afor the meritorious injection sensitivity of Node B, P _dfor low pressure dependent station is gained merit total load, P _lBfor the active loss on transmission line between Node B to substation, account form is such as formula shown in (6):

$P_{\mathrm{LB}}=\frac{{P_d}^2+{Q_d}^2}{{U_B}^2}{R}_B---\left(6\right)$

Wherein, Q _dfor the idle total load of voltage transformer station, U _bfor node B voltage amplitude, R _bfor the resistance of circuit between this substation to Node B.

If network loss variation delta Loss _aBbe negative, then illustrate that the change of supply power mode makes system losses reduce, this reconstruction strategy is effective, and Preliminary screening goes out the reconstruction strategy that these supply terminals that network loss can be made to reduce switch, and obtains the reconfiguration scheme of this low voltage power transmission system.

Preferably, the reconstruction strategy of the supply terminals switching that network loss can be made to reduce is filtered out in step S3, the scheme that can reduce system losses is screened, exclude those actual reconstruction strategy that cannot operate, as excessive etc. across 500kV great Qu, cyclization point phase difference in turned power supply, obtain the reconfiguration scheme of this low voltage power transmission system after getting rid of the actual reconstruction strategy that cannot operate.

Can system losses be reduced according to the regulation scheme that effective reconstruction strategy set is formulated, improve the economy of system cloud gray model.But reconfiguration scheme likely brings new safety problem also, as cause equipment trend out-of-limit, do not meet N-1 cut-off analyze require etc.Therefore in step S4, safety check is carried out to reconfiguration scheme, check with or without newly added equipment out-of-limit by modes such as Load flow calculation, judge to adjust reconfiguration scheme when having newly-increased equipment out-of-limit.

Adjustable strategies can be gained merit to gain merit to node according to branch road and be injected the size of sensitivity and formulate, according to the out-of-limit degree of this branch road, gain merit to gain merit to the different nodes on this branch road according to branch road and inject the difference of size of sensitivity, select to cancel the different reconstruction strategy affecting the different nodes of this branch road, guarantee transmission system fail safe.

For the powered embodiment of a kind of substation shown in Fig. 2, after supposing reconstruct, branch road l is out-of-limit, then need to analyze each reconstruction strategy, supply power mode is cause branch road l changed power to be from the impact of reconstruction strategy on this branch power of B point power supply from A point power switching by substation:

ΔP _l＝(S _l,B-S _l,A)P _d(7)

Wherein, Δ P _lfor branch road l power variation, S _l,A, S _l,Bbe respectively branch road l meritorious to node A and B meritorious injection sensitivity.

Two end nodes of branch road l are i and j, obtain branch road l meritorious to node i and j meritorious injection sensitivity S _{l, i,}s _l,jmethod be:

Step S401, according to the meritorious equation P in DC power flow method for simplifying _l=B _l(θ _i-θ _j) obtain branch power increment Delta P _lbe expressed as: Δ P _l=B _lΔ θ _i-B _lΔ θ _j;

Wherein, P _lfor flowing through the active power of branch road l, B _lfor branch road l susceptance, θ _i, θ _jfor the voltage phase angle of branch road l two ends node i and j, Δ θ _i, Δ θ _jfor the voltage phase angle increment of branch road l two ends node i and j.

Step S402, can be obtained by PQ decoupling method Load flow calculation equation: [Δ θ]=[B'] ^-1[Δ P];

Wherein, [Δ θ] and [Δ P] is respectively node voltage phase angle increment and node meritorious injection incremental vector, [B'] to gain merit the coefficient matrix of iterative equation formula for quick decoupling method, by this equation can calculate arbitrary node voltage phase angle by node each in system gain merit inject change influence degree, note node i, the phase angle increment of j and the node k proportionate relationship injected of gaining merit is $S_{\mathrm{\θj},k}=\frac{{\∂\mathrm{\θ}}_j}{{\∂P}_k};$

Step S403, the power calculating branch road l power increment and node k according to step S401 injects the proportionate relationship Δ P of increment _l=B _l(S _{θ i, k}-S _{θ j, k}) Δ P _k, namely branch road l gains merit to the meritorious injection sensitivity S of node k _l,kfor: S _l,k=B _l(S _{θ i, k}-S _{θ j, k}).

Finally should be noted that: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit, although with reference to above-described embodiment to invention has been detailed description, those of ordinary skill in the field are to be understood that: still can modify to the specific embodiment of the present invention or equivalent replacement, and not departing from any amendment of spirit and scope of the invention or equivalent replacement, it all should be encompassed in the middle of right of the present invention.

Claims (4)

1. a method for low voltage power transmission grid reconstruct, it is characterized in that, described method comprises:

Step S1, obtains electric network model and the data section of transmission system from the EMS of control centre;

Step S2, calculates the power loss sensitivity of each node in described electric network model, and the power loss sensitivity of described node is that node is gained merit the proportionate relationship that the increase of exerting oneself and the total active loss of described transmission system increase;

Step S3, calculates any one substation according to the power loss sensitivity of described node and switches the network loss change after supply terminals, filter out the supply terminals that network loss can be made to reduce and switch reconstruction strategy, obtain the reconfiguration scheme of described low voltage power transmission system;

Step S4, carries out safety check to described reconfiguration scheme, judges to adjust described reconfiguration scheme when having newly-increased equipment out-of-limit;

In described step S1, what obtain from the EMS of described control centre is real-time or the electric network model of described transmission system and data section under research mode, comprises the data of device parameter, equipment operational mode and measurement;

The power loss sensitivity S of arbitrary node k in described electric network model is calculated in described step S2 _kmethod comprise:

Step S201, lists the matrix form of Load flow calculation formula according to electric network model and operational mode:

$\left[\begin{array}{c}{\mathrm{\ΔP}}_1\\ {\mathrm{\ΔP}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔP}}_N\\ {\mathrm{\ΔQ}}_1\\ {\mathrm{\ΔQ}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔQ}}_N\end{array}\right]=\left[\begin{array}{cccccccc}\frac{\∂P_1}{\∂{\mathrm{\θ}}_1}& \frac{\∂P_1}{\∂{\mathrm{\θ}}_2}& \mathrm{...}& \frac{\∂P_1}{\∂{\mathrm{\θ}}_N}& \frac{\∂P_1}{\∂V_1}& \frac{\∂P_1}{\∂V_2}& \mathrm{...}& \frac{\∂P_1}{\∂V_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ \frac{\∂P_N}{\∂{\mathrm{\θ}}_1}& \frac{\∂P_N}{\∂{\mathrm{\θ}}_2}& \mathrm{...}& \frac{\∂P_N}{\∂{\mathrm{\θ}}_N}& \frac{\∂P_N}{\∂V_1}& \frac{\∂P_N}{\∂V_2}& \mathrm{...}& \frac{\∂P_N}{\∂V_N}\\ \frac{\∂Q_1}{\∂{\mathrm{\θ}}_1}& \frac{\∂Q_1}{\∂{\mathrm{\θ}}_2}& \mathrm{...}& \frac{\∂Q_1}{\∂{\mathrm{\θ}}_N}& \frac{\∂Q_1}{\∂V_1}& \frac{\∂Q_1}{\∂V_2}& \mathrm{...}& \frac{\∂Q_1}{\∂V_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ \frac{\∂Q_N}{\∂{\mathrm{\θ}}_1}& \frac{\∂Q_N}{\∂{\mathrm{\θ}}_2}& \mathrm{...}& \frac{\∂Q_N}{\∂{\mathrm{\θ}}_N}& \frac{\∂Q_N}{\∂V_1}& \frac{\∂Q_N}{\∂V_2}& \mathrm{...}& \frac{\∂Q_N}{\∂V_N}\end{array}\right]=\left[\begin{array}{c}{\mathrm{\Δ\θ}}_1\\ {\mathrm{\Δ\θ}}_2\\ .\\ .\\ .\\ {\mathrm{\Δ\θ}}_N\\ {\mathrm{\ΔV}}_1\\ {\mathrm{\ΔV}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔV}}_N\end{array}\right]=J\left[\begin{array}{c}{\mathrm{\Δ\θ}}_1\\ {\mathrm{\Δ\θ}}_2\\ .\\ .\\ .\\ {\mathrm{\Δ\θ}}_N\\ {\mathrm{\ΔV}}_1\\ {\mathrm{\ΔV}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔV}}_N\end{array}\right]$

In formula, V ₁-V _nand θ ₁-θ _nbe respectively each node voltage amplitude and phase angle, P ₁-P _nand Q ₁-Q _nbe respectively that each node is meritorious, idle injection, Δ V ₁-Δ V _nfor the variable quantity of each node voltage amplitude, Δ θ ₁-Δ θ _nfor the variable quantity of each node phase angle, Δ P ₁-Δ P _nvariable quantity is injected, Δ Q for each node is meritorious ₁-Δ Q _nfor the idle injection variable quantity of each node, J is coefficient matrix brief note form, obtains matrix J conversion of inverting:

$\left[\begin{array}{c}{\mathrm{\Δ\θ}}_1\\ {\mathrm{\Δ\θ}}_2\\ .\\ .\\ .\\ {\mathrm{\Δ\θ}}_N\\ {\mathrm{\ΔV}}_1\\ {\mathrm{\ΔV}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔV}}_N\end{array}\right]=J^{-1}\left[\begin{array}{c}{\mathrm{\ΔP}}_1\\ {\mathrm{\ΔP}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔP}}_N\\ {\mathrm{\ΔQ}}_1\\ {\mathrm{\ΔQ}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔQ}}_N\end{array}\right]=\left[\begin{array}{cccccccc}\frac{\∂{\mathrm{\θ}}_1}{\∂P_1}& \frac{\∂{\mathrm{\θ}}_1}{\∂P_2}& \mathrm{...}& \frac{\∂{\mathrm{\θ}}_1}{\∂P_N}& \frac{\∂{\mathrm{\θ}}_1}{\∂Q_1}& \frac{\∂{\mathrm{\θ}}_1}{\∂Q_2}& \mathrm{...}& \frac{\∂{\mathrm{\θ}}_1}{\∂Q_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ \frac{\∂{\mathrm{\θ}}_N}{\∂P_1}& \frac{\∂{\mathrm{\θ}}_N}{\∂P_2}& \mathrm{...}& \frac{\∂{\mathrm{\θ}}_N}{\∂P_N}& \frac{\∂{\mathrm{\θ}}_N}{\∂Q_1}& \frac{\∂{\mathrm{\θ}}_N}{\∂Q_2}& \mathrm{...}& \frac{\∂{\mathrm{\θ}}_N}{\∂Q_N}\\ \frac{\∂V_1}{\∂P_1}& \frac{\∂V_1}{\∂P_2}& \mathrm{...}& \frac{\∂V_1}{\∂P_N}& \frac{\∂V_1}{\∂Q_1}& \frac{\∂V_1}{\∂Q_2}& \mathrm{...}& \frac{\∂V_1}{\∂Q_N}\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ .& .& .& .& .& .& .& .\\ \frac{\∂V_N}{\∂P_1}& \frac{\∂V_N}{\∂P_2}& \mathrm{...}& \frac{\∂V_N}{\∂P_N}& \frac{\∂V_N}{\∂Q_1}& \frac{\∂V_N}{\∂Q_2}& \mathrm{...}& \frac{\∂V_N}{\∂Q_N}\end{array}\right]\left[\begin{array}{c}{\mathrm{\ΔP}}_1\\ {\mathrm{\ΔP}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔP}}_N\\ {\mathrm{\ΔQ}}_1\\ {\mathrm{\ΔQ}}_2\\ .\\ .\\ .\\ {\mathrm{\ΔQ}}_N\end{array}\right]$

J ^-1the influence degree that matrix has reacted described transmission system interior joint voltage magnitude, phase angle changes by node injecting power each in described transmission system, each element in matrix is the number ratios relation of voltage magnitude, phase angle change amount and each node injecting power variable quantity in corresponding node, according to matrix J ^-1content obtain with represent when the meritorious injection of increase by 1 unit on node k respectively, the variable quantity of voltage magnitude, phase angle on node t;

Step S202, theoretical according to tandem circuit, described transmission system network total losses computing formula of gaining merit is:

$p_L=\underset{i=1}{\overset{N}{\Σ}}\underset{j=1}{\overset{N}{\Σ}}{G}_{ij}{V}_i{V}_j{\mathrm{cos\θ}}_{ij}$

In formula, P _lfor the total network loss of described transmission system, N is the total nodes of described transmission system, G _ijfor the real part of the transadmittance between node i, j, V _i, V _jfor the voltage magnitude of node i and j, θ _ijfor the phase angle difference between nodes i, j, θ _ifor the phase angle of node i; To be gained merit total losses computing formula by described network, try to achieve the impact of the total network loss of described transmission system by any node t voltage magnitude and phase angle change: with

Step S203, calculates according to described step S201 and step S202 with trying to achieve the meritorious injection sensitivity of described transmission system network loss to a node k any in described transmission system is:

$S_k=\frac{\∂P_L}{\∂P_k}=\underset{t=1}{\overset{N}{\Σ}}(\frac{\∂P_L}{\∂{\mathrm{\θ}}_t}\frac{\∂{\mathrm{\θ}}_t}{\∂P_k}+\frac{\∂P_L}{\∂V_t}\frac{\∂V_t}{\∂P_k});$

In described step S3 according to the power loss sensitivity of described node calculate any one substation by supply power mode from A point power switching for from B point power, network loss changes delta Loss _aBsize is: Δ Loss _aB=(S _b-S _a) P _d+ P _lB;

Wherein, S _bfor the meritorious injection sensitivity of Node B, S _afor the meritorious injection sensitivity of node A, P _dfor described substation is gained merit total load, P _lBfor the active loss on transmission line between described Node B to low pressure dependent station and:

$P_{LB}=\frac{{P_d}^2+{Q_d}^2}{{U_B}^2}{R}_B;$

Wherein, Q _dfor the idle total load of voltage dependent station, U _bfor node B voltage amplitude, R _bfor the resistance of circuit between this substation to Node B;

After filtering out the reconstruction strategy of the supply terminals switching that network loss can be made to reduce in described step S3, filter out the scheme reducing described transmission system network loss, after excluding the actual reconstruction strategy that cannot operate, obtain the reconfiguration scheme of described low voltage power transmission system;

The described actual reconstruction strategy that cannot operate comprise turn power supply across 500kV great Qu and cyclization point phase difference excessive.

2. the method for claim 1, is characterized in that, the mode by Load flow calculation in described step S4 checks with or without newly added equipment out-of-limit;

Judge to adjust reconfiguration scheme when having newly-increased equipment out-of-limit, adjustable strategies gains merit to gain merit to node according to branch road to inject the size of sensitivity and formulate, according to the out-of-limit degree of described branch road, gain merit to gain merit to the different nodes on described branch road according to described branch road and inject the difference of size of sensitivity, select the different reconstruction strategy of the different nodes cancelling the described branch road of impact.

3. the method for claim 1, is characterized in that, in described step S3, supply power mode is cause branch road l changed power to be from the impact of reconstruction strategy on branch power of B point power supply from A point power switching by described substation: Δ P _l=(S _l,B-S _l,A) P _d;

Wherein, Δ P _lfor branch road l power variation, S _l,A, S _l,Bbe respectively branch road l meritorious to node A and B meritorious injection sensitivity.

4. method as claimed in claim 3, it is characterized in that, two end nodes are the branch road l of i and j, calculate described branch road l and gain merit that arbitrary node k is meritorious injects sensitivity S _l,kmethod comprise:

Step S401, according to the meritorious equation P in DC power flow method for simplifying _l=B _l(θ _i-θ _j) obtain branch power increment Delta P _lbe expressed as: Δ P _l=B _lΔ θ _i-B _lΔ θ _j;

Wherein, P _lfor flowing through the active power of branch road l, B _lfor branch road l susceptance, θ _i, θ _jfor the voltage phase angle of branch road l two ends node i and j, Δ θ _i, Δ θ _jfor the voltage phase angle increment of branch road l two ends node i and j;

Step S402, is obtained by PQ decoupling method Load flow calculation equation: [Δ θ]=[B'] ^-1[Δ P];

Wherein, [Δ θ] and [Δ P] is respectively node voltage phase angle increment and node meritorious injection increment, [B'] to gain merit the coefficient matrix of iterative equation formula for quick decoupling method, by described PQ decoupling method Load flow calculation equation calculate arbitrary node voltage phase angle by node each in system gain merit inject change influence degree, note node i, the phase angle increment of j and the node k proportionate relationship injected of gaining merit is $S_{\mathrm{\θ}i,k}=\frac{\∂{\mathrm{\θ}}_i}{\∂P_k},S_{\mathrm{\θ}j,k}=\frac{\∂{\mathrm{\θ}}_1}{\∂P_k};$

Step S403, the power calculating branch road l power increment and node k according to step S401 injects the proportionate relationship Δ P of increment _l=B _l(S _{θ i, k}-S _{θ j, k}) Δ P _k, namely branch road l gains merit to the meritorious injection sensitivity S of node k _l,kfor:

S _l,k＝B _l(S _θi,k-S _θj,k)。