CN103269069A - Method for reconstructing low-voltage power transmission system - Google Patents

Abstract

The invention provides a method for reconstructing a low-voltage power transmission system. The method comprises the following steps: step S1, obtaining a power grid model and a data section of the power transmission system in an energy management system of a dispatching center; step S2, calculating transmission loss sensitivity of each node in the power grid model, wherein the transmission loss sensitivity of the nodes is a proportional relation between the increasing of active power of the nodes and the increasing of a total active loss of the system; step S3, calculating the transmission loss sensitivity after any one low-voltage transformer substation switches a power supplying point according to the transmission loss sensitivity of the nodes and screening a power supplying point switching reconstruction policy capable of reducing transmission loss to obtain a reconstruction scheme of the low-voltage power transmission system; and step S4, carrying out safe checking on the reconstruction scheme and adjusting the reconstruction scheme when judging that newly-increased equipment over-limit exists. According to the method for reconstructing the low-voltage power transmission system disclosed by the invention, based on the transmission loss sensitivity, the power supplying point switching reconstruction policy capable of reducing the transmission loss can be screened according to the transmission loss sensitivity.

Description

The method of a kind of low voltage power transmission grid reconstruct

Technical field

The present invention relates to electric power system and calculate the 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 is providing the essential energy and power, through-put power is huge.Electric power system realizes that by the links such as transmission of electricity, power transformation and distribution in the electric power networks electrical network is to giving user's electric flux conveying, because the existence of power system impedance, electric energy is accompanied by a large amount of losses inevitably in conversion, conveying, assigning process, and is dissipated in the surrounding medium with forms such as heat energy.

Perfect day by day along with power system operation and management, the network loss rate has become an important technology economic index weighing and examine power supply enterprise's production and operation, it can reflect the height of planning and designing, manufacturing production technology and the marketing management level of electrical network, is directly connected to the economic benefit of electric power enterprise.Reducing the network loss rate is one of economic benefit important means that improves power supply enterprise.

In fact, the low voltage power transmission system losses are important component parts of regional network loss, account for more than 60% of total network loss, and as seen reducing the low voltage power transmission system losses is 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, obtain electric network model and the data section of described transmission system from the EMS of control centre;

Step S2, the network loss sensitivity of calculating each node in the described electric network model, the network loss sensitivity of described node are the proportionate relationship that the meritorious increase of exerting oneself of node and the total active loss of transmission system increase;

Step S3, the network loss of switching behind supply terminals according to any one low pressure transformer station of the network loss sensitivity calculations of described node changes, and filters out the supply terminals that network loss is reduced and switches reconstruction strategy, obtains the reconfiguration scheme of described low voltage power transmission system;

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

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

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

Step S201, list the matrix form of trend computing 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 the formula, V ₁-V _NAnd θ ₁-θ _NBe respectively each node voltage amplitude vector and angle, P ₁-P _NAnd Q ₁-Q _NBe respectively meritorious, the idle injection of each node, J is coefficient matrix brief note form, and the conversion of inverting obtains to matrix J:

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

J ^-1Matrix has reacted node voltage amplitude, angle in the described transmission system and has been subjected to the influence degree that each node injecting power changes in the described transmission system: each element in the matrix is the numerical value proportionate relationship of voltage magnitude, angle variable quantity and each node injecting power variable quantity on the corresponding node Expression is when node k goes up the meritorious injection that increases by 1 unit respectively, and node t goes up the variable quantity of voltage magnitude, phase angle;

Step S202, according to the tandem circuit theory, the meritorious total losses computing formula of described transmission system network 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 the formula, P _LBe the total network loss of described transmission system, N is the total node number of described transmission system, G _IjBe the real part of the transadmittance between node i, the j, V _i, V _jBe the voltage magnitude of node i and j, θ _IjBe the phase angle difference between node i, the j in the network, θ _iPhase angle for node i; By the network loss computing formula, try to achieve the influence that the total network loss of described transmission system is subjected 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 described transmission system network loss to the meritorious injection sensitivity of any node k in the 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 the 3rd preferred embodiment provided by the invention: any one the low pressure transformer station of network loss sensitivity calculations according to described node among the described step S3 switches to supply power mode from the power supply of B point, network loss changes delta Loss from the power supply of A point _ABSize is: Δ Loss _AB=(S _B-S _A) P _d+ P _LB

Wherein, S _BBe the meritorious injection sensitivity of Node B, S _ABe the meritorious injection sensitivity of Node B, P _dBe the meritorious total load of described low pressure transformer station, P _LBFor described Node B to the transmission line between the low pressure dependent station active loss and: $P_{\mathrm{LB}}=\frac{{P_d}^2+{Q_d}^2}{{U_B}^2}{R}_B;$

Wherein, Q _dBe the idle total load of voltage dependent station, U _BBe Node B voltage magnitude, R _BBe the resistance of this low pressure transformer station to circuit between the Node B.

In the 4th preferred embodiment provided by the invention: after filtering out the reconstruction strategy of the supply terminals switching that can make the network loss minimizing among the described step S3, filter out the scheme that reduces described transmission system network loss, exclude the reconfiguration scheme that obtains described low voltage power transmission system after the actual reconstruction strategy that can't operate.

In the 5th preferred embodiment provided by the invention: the described actual reconstruction strategy that can't operate comprises that 500kV Da Qu is striden in the commentaries on classics power supply and cyclization point phase difference is excessive.

In the 6th preferred embodiment provided by the invention: have or not newly added equipment out-of-limit by the inspection of trend calculation mode among the described step S4;

Judge when having newly-increased equipment out-of-limit reconfiguration scheme is adjusted, adjusting strategy is according to branch road is meritorious the meritorious size of injecting sensitivity of node to be formulated, out-of-limit degree according to described branch road, meritorious to the meritorious difference of injecting the size of sensitivity of the different nodes on the described branch road according to described branch road, select the different reconstruction strategy of the different nodes of the described branch road of cancellation influence.

In the 7th preferred embodiment provided by the invention: among the described step S4, described low pressure transformer station switches to supply power mode the reconstruction strategy of powering from B point the influence of described branch power is caused that branch road l power is changed to: Δ P from the power supply of A point _l=(S _{L, B}-S _{L, A}) P _d

Wherein, Δ P _lBe branch road l power variation, S _{L, A}, S _{L, B}It is meritorious to node A and the meritorious injection of B sensitivity to be respectively branch road l.

In the 8th preferred embodiment provided by the invention: two end nodes are the branch road l of i and j, calculate meritorious arbitrary node k is gained merit of described branch road l and inject sensitivity S _{L, k}Method comprise:

Step S401 is according to the meritorious equation P in the 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 _lBe branch road l susceptance, θ _i, θ _jBe the voltage phase angle of branch road l two ends node i and j, Δ θ _i, Δ θ _jVoltage phase angle increment for branch road l two ends node i and j.

Step S402 can be obtained by PQ decoupling method trend accounting equation: [Δ θ]=[B'] ^-1[Δ P];

Wherein, [Δ θ] is respectively node voltage angle increment and the meritorious incremental vector of injecting of node mutually with [Δ P], [B'] is the coefficient matrix of the meritorious iterative equation formula of quick decoupling method, calculate the arbitrary node voltage phase angle by described PQ decoupling method trend accounting equation and be subjected to the meritorious influence degree that changes of injecting of each node in the system, the note node i, the meritorious proportionate relationship of injecting of the phase angle increment of j and node k 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 that calculates 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, k}For: 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 provided by the invention reconstruct comprises:

1, the method of a kind of low voltage power transmission grid provided by the invention reconstruct is based on network loss sensitivity, 110kV and following low voltage electric network are generally followed 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 a plurality of, the method of a kind of network reconfiguration provided by the invention is unit with low pressure transformer station, the whether needs reconstruct of current low pressure transformer station is judged in sensitivity according to network loss, filter out the supply terminals that network loss is reduced and switch reconstruction strategy, can be under the situation that does not increase investment and build, by changing the rack topological structure, the digging system potentiality, reduce system power dissipation, the economy of raising system operation, based on network loss sensitivity, explicit physical meaning, find the solution convenient and swift, finely tune on basis in the network topology structure of current system, the number of switches that participant status is adjusted is few, thereby result of calculation is workable, but the guidance system actual motion, the economy of the operation of raising system conscientiously.

2, filter out after the supply terminals that network loss is reduced switches reconstruction strategy, can use various logic that reconfiguration scheme is screened, stride 500kV Da Qu as whether changeing power supply, whether cyclization point phase difference is excessive etc., remove infeasible reconstruction strategy, simplify computational process, screening process adopts open by design, and the screening logic can expand in actual use flexibly.

3, use sensitivity method that the reconfiguration scheme that obtains is adjusted, elimination is newly-increased out-of-limit, improves the feasibility of reconfiguration scheme.In eliminating out-of-limit process, take all factors into consideration the network loss sensitivity of reconstruction strategy and to the sensitivity of branch power, not causing on the newly-increased out-of-limit basis, reduce system losses as much as possible, the economy of raising system operation.

Description of drawings

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

Be illustrated in figure 2 as the schematic diagram that a kind of low pressure provided by the invention transformer station is subjected to the embodiment of electricity.

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 comprises as shown in Figure 1:

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

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

Step S3 changes according to the network loss behind any one low pressure transformer station switching supply terminals of network loss sensitivity calculations of node, filters out the supply terminals that network loss is reduced and switches reconstruction strategy, obtains the reconfiguration scheme of this low voltage power transmission system.

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

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

Need to calculate according to the electric network model that obtains and data section the network loss sensitivity of each node in the electric network model among the step S2, existing network loss sensitivity computing method is a lot, as transposition Jacobi matrix method, B Y-factor method Y, the Impedance Moment tactical deployment of troops, admittance matrix method etc., can adopt comparatively accurate and ripe transposition Jacobi matrix method to calculate.Calculate the network loss sensitivity S of arbitrary node i in the electric network model among a kind of step S2 provided by the invention _iThe embodiment of method be:

Step S201, can list the matrix form of trend computing 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 the formula, V ₁-V _NAnd θ ₁-θ _NBe respectively each node voltage amplitude vector and angle, P ₁-P _NAnd Q ₁-Q _NBe respectively meritorious, the idle injection of each node, J is coefficient matrix brief note form, and the conversion of inverting obtains to matrix J:

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

J is described as following formula ^-1Matrix has reacted that node voltage amplitude, angle are subjected to the influence degree that each node injecting power changes in the system in the system: each element in the matrix is the numerical value proportionate relationship of voltage magnitude, angle variable quantity and each node injecting power variable quantity on the corresponding node.As

Expression is when node k goes up the meritorious injection that increases by 1 unit respectively, and node t goes up the variable quantity of voltage magnitude, phase angle.

Step S202, according to the tandem circuit theory, the meritorious total losses computing formula of transmission system network 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 the formula, P _LBe the total network loss of system, N is the total node number of system, G _IjBe the real part of the transadmittance between node i, the j, V _i, V _jBe the voltage magnitude of node i and j, θ _IjBe the phase angle difference between node i, the j in the network, θ _iPhase angle for node i.By the meritorious total losses computing formula of this network, can try to achieve the influence that the total network loss of system is subjected 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 transmission system network loss to the meritorious injection sensitivity of any node k in this transmission system is: $S_k=\frac{{\∂P}_L}{{\∂P}_k}=\underset{t=1}{\overset{N}{\mathrm{\Σ}}}(\frac{{\∂P}_L}{{\∂\mathrm{\θ}}_t}\frac{{\∂\mathrm{\θ}}_t}{{\∂P}_k}+\frac{{\∂P}_L}{{\∂V}_t}\frac{{\∂V}_t}{{\∂P}_k})$

A kind of low pressure transformer station that being illustrated in figure 2 as invention provides is subjected to the schematic diagram of the embodiment of electricity, as shown in Figure 2, this low pressure transformer station is its power supply by the node A of high voltage power transmisson system at this moment, consider that for improving power supply reliability it is this dependent station power supply that grid can also change by Node B by change related switch running status.

R among Fig. 2 _B+ jX _BBe the connecting line resistance value of B point to dependent station.Because 2 diverse locations that are positioned at high voltage power transmisson system of A, B, its network loss level of sensitivity is also variant, is designated as S respectively _A, S _B

Step S3 mesolow transformer station switches to supply power mode from the power supply of B point, network loss changes delta Loss from the power supply of A point _ABSize is:

ΔLoss _AB＝(S _B-S _A)P _d+P _LB (5)

Wherein, S _BBe the meritorious injection sensitivity of Node B, S _ABe the meritorious injection sensitivity of Node B, P _dBe the meritorious total load of low pressure dependent station, P _LBBe the active loss of Node B to the transmission line between the low pressure transformer station, account form as the formula (6):

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

Wherein, Q _dBe the idle total load of voltage transformer station, U _BBe Node B voltage magnitude, R _BBe the resistance of this low pressure transformer station to circuit between the Node B.

If network loss variation delta Loss _ABFor negative, illustrate that then 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 is reduced switch, and obtains the reconfiguration scheme of this low voltage power transmission system.

Preferably, filter out the reconstruction strategy of the supply terminals switching that can make the network loss minimizing among the step S3, the scheme that can reduce system losses is screened, exclude those the actual reconstruction strategy that can't operate, as changeing power supply, to stride 500kV Da Qu, cyclization point phase difference excessive etc., gets rid of the reconfiguration scheme that obtains this low voltage power transmission system after the actual reconstruction strategy that can't operate.

The regulation scheme of formulating according to effective reconstruction strategy set can reduce system losses, the economy of raising system operation.Yet reconfiguration scheme might bring new safety problem also, as cause the equipment trend out-of-limit, do not satisfy N-1 and cut-off and analyze to require etc.Therefore among the step S4 reconfiguration scheme is carried out safety check, have or not newly added equipment out-of-limit by mode inspections such as trend calculating, judge when having newly-increased equipment out-of-limit reconfiguration scheme is adjusted.

Adjusting strategy can formulate the meritorious size of injecting sensitivity of node according to branch road is meritorious, out-of-limit degree according to this branch road, meritorious to the meritorious difference of injecting the size of sensitivity of the different nodes on this branch road according to branch road, select cancellation to influence the different reconstruction strategy of the different nodes of this branch road, guarantee the transmission system fail safe.

Being subjected to the embodiment of electricity with shown in Figure 2 a kind of low pressure transformer station is example, branch road l is out-of-limit after supposing reconstruct, then need analyze each reconstruction strategy, low pressure transformer station switches to supply power mode the reconstruction strategy of powering from B point the influence of this branch power is caused that branch road l power is changed to from A point power supply:

ΔP _l＝(S _l,B-S _l,A)P _d (7)

Wherein, Δ P _lBe branch road l power variation, S _{L, A}, S _{L, B}It is meritorious to node A and the meritorious injection of B sensitivity to be respectively branch road l.

Two end nodes of branch road l are i and j, and it is meritorious to node i and the meritorious sensitivity S of injecting of j to obtain branch road l _{L, i,}S _{L, j}Method be:

Step S401 is according to the meritorious equation P in the 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 _lBe branch road l susceptance, θ _i, θ _jBe the voltage phase angle of branch road l two ends node i and j, Δ θ _i, Δ θ _jVoltage phase angle increment for branch road l two ends node i and j.

Step S402 can be obtained by PQ decoupling method trend accounting equation: [Δ θ]=[B'] ^-1[Δ P];

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

Step S403, the power that calculates 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, k}For: S _{L, k}=B _l(S _{θ i, k}-S _{θ j, k}).

Should be noted that at last: 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 the present invention is had been described in detail, those of ordinary skill in the field are to be understood that: still can make amendment or be equal to replacement the specific embodiment of the present invention, and do not break away from any modification of spirit and scope of the invention or be equal to replacement, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (9)

1. the method for low voltage power transmission grid reconstruct 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, the network loss sensitivity of calculating each node in the described electric network model, the network loss sensitivity of described node are the proportionate relationship that the meritorious increase of exerting oneself of node and the total active loss of described transmission system increase;

Step S3, the network loss of switching behind supply terminals according to any one low pressure transformer station of the network loss sensitivity calculations of described node changes, and filters out the supply terminals that network loss is reduced and switches reconstruction strategy, obtains the reconfiguration scheme of described low voltage power transmission system;

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

2. the method for claim 1, it is characterized in that, among the described step S1, what obtain from the EMS of described control centre is electric network model and the data section of described transmission system under real-time or the research mode, comprises the data of device parameter, equipment operational mode and measurement.

3. the method for claim 1 is characterized in that, calculates the network loss sensitivity S of arbitrary node k in the described electric network model among the described step S2 _kMethod comprise:

Step S201, list the matrix form of trend computing 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 the formula, V ₁-V _NAnd θ ₁-θ _NBe respectively each node voltage amplitude vector and angle, P ₁-P _NAnd Q ₁-Q _NBe respectively meritorious, the idle injection of each node, J is coefficient matrix brief note form, and the conversion of inverting obtains to matrix J:

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

J ^-1Matrix has reacted node voltage amplitude, angle in the described transmission system and has been subjected to the influence degree that each node injecting power changes in the described transmission system: each element in the matrix is the numerical value proportionate relationship of voltage magnitude, angle variable quantity and each node injecting power variable quantity on the corresponding node, according to matrix J ^-1Content obtain Expression is when node k goes up the meritorious injection that increases by 1 unit respectively, and node t goes up the variable quantity of voltage magnitude, phase angle;

Step S202, according to the tandem circuit theory, the meritorious total losses computing formula of described transmission system network 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 the formula, P _LBe the total network loss of described transmission system, N is the total node number of described transmission system, G _IjBe the real part of the transadmittance between node i, the j, V _i, V _jBe the voltage magnitude of node i and j, θ _IjBe the phase angle difference between node i, the j in the network, θ _iPhase angle for node i; By the meritorious total losses computing formula of described network, try to achieve the influence that the total network loss of described transmission system is subjected 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 described transmission system network loss to the meritorious injection sensitivity of any node k in the described transmission system is: $S_k=\frac{{\∂P}_L}{{\∂P}_k}=\underset{t=1}{\overset{N}{\mathrm{\Σ}}}(\frac{{\∂P}_L}{{\∂\mathrm{\θ}}_t}\frac{{\∂\mathrm{\θ}}_t}{{\∂P}_k}+\frac{{\∂P}_L}{{\∂V}_t}\frac{{\∂V}_t}{{\∂P}_k}).$

4. the method for claim 1 is characterized in that, any one the low pressure transformer station of network loss sensitivity calculations according to described node among the described step S3 switches to supply power mode from the power supply of B point, network loss changes delta Loss from the power supply of A point _ABSize is: Δ Loss _AB=(S _B-S _A) P _d+ P _LB

Wherein, S _BBe the meritorious injection sensitivity of Node B, S _ABe the meritorious injection sensitivity of Node B, P _dBe the meritorious total load of described low pressure transformer station, P _LBFor described Node B to the transmission line between the low pressure dependent station active loss and: $P_{\mathrm{LB}}=\frac{{P_d}^2+{Q_d}^2}{{U_B}^2}{R}_B;$

Wherein, Q _dBe the idle total load of voltage dependent station, U _BBe Node B voltage magnitude, R _BBe the resistance of this low pressure transformer station to circuit between the Node B.

5. the method for claim 1, it is characterized in that, after filtering out the reconstruction strategy of the supply terminals switching that can make the network loss minimizing among the described step S3, filter out the scheme that reduces described transmission system network loss, exclude the reconfiguration scheme that obtains described low voltage power transmission system after the actual reconstruction strategy that can't operate.

6. method as claimed in claim 5 is characterized in that, the described actual reconstruction strategy that can't operate comprises that 500kV Da Qu is striden in the commentaries on classics power supply and cyclization point phase difference is excessive.

7. the method for claim 1 is characterized in that, has or not newly added equipment out-of-limit by the inspection of trend calculation mode among the described step S4;

Judge when having newly-increased equipment out-of-limit reconfiguration scheme is adjusted, adjusting strategy is according to branch road is meritorious the meritorious size of injecting sensitivity of node to be formulated, out-of-limit degree according to described branch road, meritorious to the meritorious difference of injecting the size of sensitivity of the different nodes on the described branch road according to described branch road, select the different reconstruction strategy of the different nodes of the described branch road of cancellation influence.

8. method as claimed in claim 4 is characterized in that, among the described step S4, described low pressure transformer station switches to supply power mode the reconstruction strategy of powering from B point the influence of described branch power is caused that branch road l power is changed to: Δ P from the power supply of A point _l=(S _{L, B}-S _{L, A}) P _d

Wherein, Δ P _lBe branch road l power variation, S _{L, A}, S _{L, B}It is meritorious to node A and the meritorious injection of B sensitivity to be respectively branch road l.

9. method as claimed in claim 8 is characterized in that, two end nodes are the branch road l of i and j, calculates the meritorious sensitivity S of injecting of the meritorious arbitrary node k of described branch road l _{L, k}Method comprise:

Step S401 is according to the meritorious equation P in the 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 _lBe branch road l susceptance, θ _i, θ _jBe the voltage phase angle of branch road l two ends node i and j, Δ θ _i, Δ θ _jVoltage phase angle increment for branch road l two ends node i and j;

Step S402 is obtained by PQ decoupling method trend accounting equation: [Δ θ]=[B'] ^-1[Δ P];

Wherein, [Δ θ] is respectively node voltage angle increment and the meritorious incremental vector of injecting of node mutually with [Δ P], [B'] is the coefficient matrix of the meritorious iterative equation formula of quick decoupling method, calculate the arbitrary node voltage phase angle by described PQ decoupling method trend accounting equation and be subjected to the meritorious influence degree that changes of injecting of each node in the system, the note node i, the meritorious proportionate relationship of injecting of the phase angle increment of j and node k 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 that calculates 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, k}For: S _{L, k}=B _l(S _{θ i, k}-S _{θ j, k}).

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