CN113629717A - Optimal power flow calculation method, system, storage medium and calculation equipment - Google Patents

Optimal power flow calculation method, system, storage medium and calculation equipment Download PDF

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CN113629717A
CN113629717A CN202110979986.1A CN202110979986A CN113629717A CN 113629717 A CN113629717 A CN 113629717A CN 202110979986 A CN202110979986 A CN 202110979986A CN 113629717 A CN113629717 A CN 113629717A
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node
tcpst
power flow
voltage
optimal power
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张宁宇
李群
陈静
朱鑫要
李铮
刘建坤
王大江
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Electric Power Research Institute of State Grid Jiangsu Electric Power Co Ltd
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Electric Power Research Institute of State Grid Jiangsu Electric Power Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/04—Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
    • H02J3/06—Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/10—Flexible AC transmission systems [FACTS]

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Abstract

The invention discloses an optimal power flow calculation method, a system, a storage medium and calculation equipment.

Description

Optimal power flow calculation method, system, storage medium and calculation equipment
Technical Field
The invention relates to an optimal power flow calculation method, an optimal power flow calculation system, a storage medium and calculation equipment, and belongs to the field of analysis and calculation of power systems.
Background
With the rapid development of economy, the power grid load of China is increasing day by day, however, the power supply capacity of the power grid in part of regions is gradually insufficient due to factors such as uneven land resource distribution, difficulty in grid expansion work and the like, and the increasing life requirements of people cannot be met, so that the search for a method for relieving the contradiction is the primary task of the current power grid construction.
The TCPST (thyristor-containing controllable phase shifter) is used as a new generation of flexible alternating current transmission device, and can realize flexible control of bus voltage and line tide by adjusting parameters of controllable elements without changing the original grid of a system, thereby eliminating line heavy load and improving the zone power supply capacity, and therefore, the TCPST has wide application prospect.
An optimal power flow calculation method (OPF) is an important branch in the field of optimal operation of a power system, and with the wide application of TCPST, the optimal power flow calculation method of the power system containing the TCPST is urgently needed to be researched.
Disclosure of Invention
The invention provides an optimal power flow calculation method, an optimal power flow calculation system, a storage medium and calculation equipment, which solve the problems disclosed in the background art.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
an optimal power flow calculation method comprises the following steps:
establishing a TCPST equivalent node injection power model under the original admittance matrix of the system on the basis of the real-time parameters of the system and the operation principle of the TCPST; wherein the system is a system comprising a TCPST;
establishing a system optimal power flow calculation model considering the controllable phase shifter according to the TCPST equivalent node injection power model;
and solving the system optimal power flow calculation model to obtain the system optimal power flow.
The TCPST equivalent node injection power model is as follows:
Figure BDA0003228716960000021
Figure BDA0003228716960000022
wherein, PTaInjecting active power, Q, for TCPST equivalent to node aTaEquivalent injection of reactive power, P, for TCPST to contact aTbInjecting active power, Q, for TCPST equivalent to contact bTbEquivalent injection of reactive power for TCPST to contact b, bRbThe equivalent susceptance of the branch in which the TCPST is located,
Figure BDA0003228716960000023
is the phase shift angle, U, of TCPSTaIs the voltage of node a, UbIs the voltage at the node b and is,
Figure BDA0003228716960000024
is the voltage angle difference between node R and node b of the branch where TCPST is located, babIs the equivalent susceptance of the lines a-b,
Figure BDA0003228716960000025
is the voltage angle difference between node a and node b.
The system optimal power flow calculation model considering the controllable phase shifter comprises a target function;
the method comprises the following specific steps:
Figure BDA0003228716960000026
wherein f is the active network loss of the system, n is the number of system nodes, and UiIs the voltage of node i, UjIs the voltage of node j, GijFor the i-j conductance, theta, of the lines in the system admittance matrixijIs the voltage phase angle difference between node i and node j.
The system optimal power flow calculation model considering the controllable phase shifter comprises equality constraint;
the method comprises the following specific steps:
and (3) constraint of an equation:
Figure BDA0003228716960000031
wherein, PGiActive power, Q, generated for the generator on node iGiFor reactive power, P, generated by generators on node iDiIs the active load of node i, QDiBeing reactive load of node i, BijFor the line i-j susceptance, P, in the system admittance matrixTiInjecting active power, Q, for TCPST equivalent to node iTiInjecting reactive power for TCPST to the equivalent of the contact point i, n is the number of system nodes, UiIs the voltage of node i, UjIs the voltage of node j, GijFor the i-j conductance, theta, of the lines in the system admittance matrixijIs the voltage phase angle difference between node i and node j.
The system optimal power flow calculation model considering the controllable phase shifter comprises inequality constraints;
the method comprises the following specific steps:
TCPST capacity inequality constraint:
Figure BDA0003228716960000032
wherein, bRbIs the equivalent susceptance, g, of the branch in which the TCPST is locatedRbIs the equivalent conductance of the branch in which TCPST is located, is the conjugate, SmaxIn order to be the upper capacity limit of the TCPST,
Figure BDA0003228716960000033
for the TCPST series side voltage source voltage vector,
Figure BDA0003228716960000034
is a vector of the voltage at the node a,
Figure BDA0003228716960000035
is the voltage vector at node b;
TCPST tuning controls the inequality constraint:
Figure BDA0003228716960000036
wherein, UBFor TCPST series side voltage source voltage, thetaBFor the voltage phase angle, U, of the TCPST series side voltage sourceBmaxIs UBUpper limit of (U), UBminIs UBLower limit of (a), thetaBmaxIs thetaBUpper limit of (e), thetaBminIs thetaBThe lower limit of (d);
the remaining inequalities constrain:
Figure BDA0003228716960000041
wherein, UiIs the voltage of node i, UjIs the voltage of node j, UimaxIs UiUpper limit of (B), PGiActive power, Q, generated for the generator on node iGiReactive power, U, generated for generators on node iiminIs UiLower limit of (a), thetaiIs the voltage phase angle, θ, of node iimaxIs thetaiUpper limit of (e), thetaiminIs thetaiLower limit of (D), PijFor active power of lines i-j, QijFor reactive power of lines i-j, Pij,maxIs PijUpper limit of (B), Pij,minIs PijLower limit of (2), Qij,maxIs QijUpper limit of (2), Qij,minIs QijLower limit of (D), PGi,maxIs PGiUpper limit of (B), PGi,minIs PGiLower limit of (2), QGi,maxIs QGiUpper limit of (2), QGi,minIs QGiThe lower limit of (3).
Solving a system optimal power flow calculation model to obtain a system optimal power flow, wherein the specific process comprises the following steps:
and solving the system optimal power flow calculation model by adopting a multi-center-correction inner point method to obtain the system optimal power flow.
The multi-center-correction interior point method is an improved multi-center-correction interior point method, and the improved multi-center-correction interior point method adjusts the step length of the affine direction and the mapping parameters of the hyper-stereo space on the basis of the traditional multi-center-correction interior point method;
the adjusted affine direction step length is as follows:
α′＝min{max{αaf,αce,αco}+δ,1}
wherein alpha' is the adjusted affine direction step length, alphaafIs originally shot-like direction step length, alphaceStep size of center direction, αcoTo correct the direction step, δ is the affine direction step increment;
the adjusted hyper-stereo space mapping parameters are as follows:
δ∈[0.4,0.7]maximum value of spatial threshold βmax∈[5,8]Minimum value of spatial threshold βmin∈[0.4,0.6]。
An optimal power flow calculation system comprising:
injecting a power model module: establishing a TCPST equivalent node injection power model under the original admittance matrix of the system on the basis of the real-time parameters of the system and the operation principle of the TCPST; wherein the system is a system comprising a TCPST;
an optimal power flow calculation model module: establishing a system optimal power flow calculation model considering the controllable phase shifter according to the TCPST equivalent node injection power model;
a solving module: and solving the system optimal power flow calculation model to obtain the system optimal power flow.
A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform an optimal power flow calculation optimization method.
A computing device comprising one or more processors, one or more memories, and one or more programs stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs including instructions for performing an optimal power flow calculation method.
The invention achieves the following beneficial effects: the method is based on the TCPST equivalent node injection power model, the system optimal power flow calculation model considering the controllable phase shifter is established, the system optimal power flow calculation model is solved, the system optimal power flow is obtained, the optimal power flow calculation of the power system containing the TCPST is realized, a foundation is provided for formulating the optimal control strategy of the TCPST, and the safety and the stability of the power system are improved.
Drawings
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a TCPST structural model;
FIG. 3 is a TCPST equivalent node injection power model;
FIG. 4 is a voltage amplitude comparison diagram before and after an IEEE14 node system is added with a TCPST;
FIG. 5 is a voltage amplitude comparison diagram before and after an IEEE30 node system is added with a TCPST;
FIG. 6 is a voltage amplitude comparison before and after the IEEE118 node system adds TCPST.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
As shown in fig. 1, an optimal power flow calculation method includes the following steps:
step 1, establishing a TCPST equivalent node injection power model under the original admittance matrix of a system on the basis of system real-time parameters and the operation principle of the TCPST; wherein the system is a system comprising a TCPST;
step 2, establishing a system optimal power flow calculation model considering the controllable phase shifter according to the TCPST equivalent node injection power model;
and 3, solving the system optimal power flow calculation model to obtain the system optimal power flow.
The method is based on the TCPST equivalent node injection power model, the system optimal power flow calculation model considering the controllable phase shifter is established, the system optimal power flow calculation model is solved, the system optimal power flow is obtained, the optimal power flow calculation of the power system containing the TCPST is achieved, a foundation is provided for formulating the optimal control strategy of the TCPST, and the safety and the stability of the power system are improved.
Analyzing the operation principle of the TCPST based on the structure of the TCPST, as shown in FIG. 2, the TCPST mainly comprises three parts, namely a parallel transformer, a series transformer and a control device; the control device is composed of power electronic components, and the difference of the TCPST characteristics and the control mode is caused by the difference of the structure of the control device; in the drawings
Figure BDA0003228716960000071
The voltage vector at the head end of the branch in which the TCPST is located, i.e. the voltage vector at the node a,
Figure BDA0003228716960000072
the voltage vector at the end of the branch in which TCPST is located, i.e. the voltage vector at node b,
Figure BDA0003228716960000073
for the newly added virtual node voltage phasor r of the TCPST access systemRbIs the equivalent resistance, x, of the branch in which the TCPST is locatedRbIs the equivalent reactance, P, of the branch in which the TCPST is located0Active power, P, of the line before the addition of TCPST1Active power of the line after adding for TCPST.
The TCPST steady-state model adopts a series voltage source and parallel current source independent branch model, and the basic idea of the model is to decompose a branch where the TCPST is located into a TCPST parallel branch and an original line branch, so that an admittance matrix containing a TCPST system is still obtained according to a traditional power flow method and is a symmetric matrix, and the complexity of calculation caused by adding equipment is avoided.
According to circuit principles, the TCPST equivalent voltage and current sources can be expressed as:
Figure BDA0003228716960000074
Figure BDA0003228716960000075
wherein the content of the first and second substances,
Figure BDA0003228716960000076
is the phase shift angle of the TCPST,
Figure BDA0003228716960000077
is a vector of the voltage at the node a,
Figure BDA0003228716960000078
for the current phasor at the series side of the TCPST,
Figure BDA0003228716960000079
for the TCPST series side voltage source voltage vector,
Figure BDA00032287169600000710
is a vector of the voltage at the node b,
Figure BDA00032287169600000711
equivalent current source and equivalent voltage source representing TCPST, respectively;
at the same time
Figure BDA00032287169600000712
Figure BDA0003228716960000081
Wherein the content of the first and second substances,
Figure BDA0003228716960000082
representing the phasor of the current flowing out of node a,
Figure BDA0003228716960000083
representing the phasor of the current flowing into node b.
Based on the above transformation, the TCPST can be moved out of the network, the effect of the TCPST is equivalent to the node injection power at both ends, and the TCPST equivalent node injection power model under the original admittance matrix of the system is not changed as shown in fig. 3, which specifically includes the following steps:
Figure BDA0003228716960000084
Figure BDA0003228716960000085
wherein, PTaInjecting active power, Q, for TCPST equivalent to contact aTaEquivalent injection of reactive power, P, for TCPST to contact aTbInjecting active power, Q, for TCPST equivalent to contact bTbEquivalent injected reactive power, g, for TCPST to contact bRbIs the equivalent conductance of the branch in which it is located, bRbIs the equivalent susceptance, g, of the branch in which the TCPST is locatedRb+jbRb＝(rRb+jxRb)-1，UaIs the voltage of node a, UbIs the voltage at the node b and is,
Figure BDA0003228716960000086
the voltage angle difference between node R and node b of the branch where TCPST is located,
Figure BDA0003228716960000087
is the voltage angle difference of node a and node b; the TCPST is located at different positions and the injection power model is different.
After the controllable phase shifter is added into the system, the influence of the controllable phase shifter on the power flow of the system can be represented by the equivalent injection power; considering that in the high-voltage transmission line, the equivalent conductance of the line is far smaller than the equivalent susceptance of the line, so the equivalent conductance of the line can be ignored, and because the phase angle of the controllable phase shifter is not different from the phase angle of the node voltage, the reactive component of the injected power of the additional node can be ignored and only the active component is counted; thus, the above model can be simplified to:
Figure BDA0003228716960000091
Figure BDA0003228716960000092
wherein, babIs the equivalent susceptance of the lines a-b.
According to the simplified model, a system optimal power flow calculation model considering the controllable phase shifter can be established, and the system optimal power flow calculation model specifically comprises an objective function, equality constraints and inequality constraints.
In order to research the regulation effect of the controllable phase shifter on the line active loss and simplify the calculation, an OPF model based on a rectangular coordinate system is established by taking the minimum system active network loss as an objective function, and the objective function is expressed as follows:
Figure BDA0003228716960000093
wherein f is the active network loss of the system, n is the number of system nodes, and UiIs the voltage of node i, UjIs the voltage of node j, GijFor the i-j conductance, theta, of the lines in the system admittance matrixijIs the voltage phase angle difference between node i and node j.
The constraint conditions comprise equality constraint and inequality constraint;
the equation is constrained as follows:
the power balance equation is as follows:
Figure BDA0003228716960000094
wherein, PGiActive power, Q, generated for the generator on node iGiThe reactive power generated by the generator on the node i is 0 when the node i is not connected with the generator; pDiIs the active load of node i, QDiBeing reactive load of node i, BijSusceptances for lines i-j in a system admittance matrix;
for a line added with a TCPST, an equivalent injection power needs to be added to the two end nodes of the line, so when the TCPST is installed on the line i-j (i.e. the line between the node i and the node j), the power balance equation can be further expressed as:
Figure BDA0003228716960000101
wherein, PTiInjecting active power, Q, for TCPST equivalent to node iTiReactive power is injected for the TCPST equivalent to contact i.
TCPST capacity inequality constraint:
Figure BDA0003228716960000102
wherein is a conjugate, SmaxThe upper TCPST capacity limit.
TCPST tuning controls the inequality constraint:
Figure BDA0003228716960000103
wherein, UBFor TCPST series side voltage source voltage, thetaBFor the voltage phase angle, U, of the TCPST series side voltage sourceBmaxIs UBUpper limit of (U), UBminIs UBLower limit of (a), thetaBmaxIs thetaBUpper limit of (e), thetaBminIs thetaBThe lower limit of (3).
The remaining inequalities constrain:
Figure BDA0003228716960000111
wherein, UimaxIs UiUpper limit of (U), UiminIs UiLower limit of (a), thetaiIs the voltage phase angle, θ, of node iimaxIs thetaiUpper limit of (e), thetaiminIs thetaiLower limit of (D), PijFor active power of lines i-j, QijFor reactive power of lines i-j, Pij,maxIs PijUpper limit of (B), Pij,minIs PijLower limit of (2), Qij,maxIs QijUpper limit of (2), Qij,minIs QijLower limit of (D), PGi,maxIs PGiUpper limit of (B), PGi,minIs PGiLower limit of (2), QGi,maxIs QGiUpper limit of (2), QGi,minIs QGiThe lower limit of (3).
And solving the system optimal power flow calculation model by adopting a multi-center-correction inner point method to obtain the system optimal power flow. The traditional multi-center-correction inner point method effectively determines that the calculation times of center-correction in each iteration is the difficulty of MCCIPM, if the calculation times are less, the expected effect cannot be achieved, and if the calculation times are more, the calculated amount is increased; therefore, the affine direction step length and the hyper-stereo space mapping parameters are adjusted on the basis of the traditional multi-center-correction interior point method;
the adjusted affine direction step length is as follows:
α′＝min{max{αaf,αce,αco}+δ,1}
wherein alpha' is the adjusted affine direction step length, alphaafIs originally shot-like direction step length, alphaceStep size of center direction, αcoTo correct the direction step, δ is the affine direction step increment;
the adjusted hyper-stereo space mapping parameters are as follows:
δ∈[0.4,0.7]maximum value of spatial threshold βmax∈[5,8]Minimum value of spatial threshold βmin∈[0.4,0.6]。
The modified multicenter-corrected interior point method is as follows:
(1) firstly, a relaxation variable l ═ l is introduced1,...,lr]T、u＝[u1,...ur]TConverting inequality constraints in the optimal power flow model into equality constraints;
(2) the lagrange function is constructed as follows:
Figure 1
in the formula, r inequality constraints are in total; y ═ y1,....,ym]T、z＝[z1,...,zr]T、w＝[w1,...wr]TLagrange multipliers representing equality constraints and inequality constraints, respectively; l ═ l1,...,lr]T、u＝[u1,...ur]TExpressing a relaxation variable of inequality constraint, and converting the problem into an optimization problem only containing equality constraint; μ is a perturbation factor of the barrier function;
(3) applying the KKT (Karush-Kuhn-Tucker) first order requirement to the Lagrangian function yields:
Figure BDA0003228716960000122
wherein L ═ diag (L)1,…,lr)，U＝diag(u1,…,ur)， Z＝diag(z1,…,zr)，W＝diag(w1,…,wr) (ii) a e is an r-dimensional vector with elements of 1;
the above formula also becomes a perturbation KKT system, wherein the 2 nd, 3 rd and 4 th equations and implicit conditions l >0 and u >0 represent feasibility of the original problem; the 1 st equation and implicit conditions z >0, w >0 represent the feasibility of the dual problem; the 5 th and 6 th equations are generally called mu compensation conditions, and the high-order interior point method is performed for the mu compensation conditions;
(4) the perturbation KKT system is a nonlinear equation system and can be solved by a Newton method, for this purpose, various equations in the system are expanded by Taylor series, and a high-order term of a mu compensation condition is reserved to obtain:
Figure BDA0003228716960000131
writing the above equation in matrix form:
Figure BDA0003228716960000141
the above equation is a correction equation of the high-order interior point method, and is written as Δ λ ═ (Δ z, Δ l, Δ w, Δ u, Δ x, Δ y)T、
Figure BDA0003228716960000142
Coefficient matrix to the left of the above equation, daf、dce、dcoRespectively 1, 2 and 3 on the right side of the above formula, and wherein
Figure BDA0003228716960000143
The above formula can be rewritten as:
Figure BDA0003228716960000144
(5) by
Figure BDA0003228716960000145
The solved newton direction Δ λ is also correspondingly composed of 3 directions:
Δλ＝Δλaf+Δλce+Δλco
in the formula, Δ λaf、Δλce、ΔλcoAre respectively daf、dce、dcoA corresponding direction; delta lambdaafIs an affine direction, i.e., a direction obtained when the center parameter σ is 0 in the primal dual inlier method; delta lambdaceIs the center direction, i.e. the direction when the center parameter σ is 1, which ensures that the search path advances along the obstacle trajectory without deviating from the feasible region; delta lambdacoCalled the correction direction, which compensates for the original nonlinear characteristics of the affine direction, since the high-order nonlinear terms Δ L Δ Ze and Δ U Δ We are not taken into account in the conventional interior point method, compensation is given in the high-order interior point method;
(6) in the forecast stage, first of all
Figure BDA0003228716960000151
Determining affine direction Δ λafThen calculating the radiation step length alphaafAffine compensation gap rhoafAnd affine obstacle parameter muaf。
(7) In the correction stage, the vector obtained in the prediction stage is mapped into a hyper-stereo (hypercube) space, and in order to seek the correction direction more quickly and reduce the iteration times, the step length of the original imitation direction is increased as follows:
α′＝min{max{αaf,αce,αco}+δ,1}
wherein alpha' is the adjusted affine direction step length, alphaafIs originally shot-like direction step length, alphaceStep size of center direction, αcoTo correct the direction step, δ is the affine direction step increment;
(8) and selecting the maximum value in the step length of the three directions as the affine step length of the iterative computation to ensure the rapidity of correcting the direction.
Based on this, the original and dual variables are updated to obtain:
m′＝m(k)+α′·Δb1
in the formula, m' is each variable after iterative update; Δ b1Is an affine direction; k represents the number of iterations; m ═ x y z w l u]Is each variable in the calculation;
(9) let vectors p ', q' be:
Figure BDA0003228716960000152
wherein l '═ diag [ l'1,...,l′r]T，z′＝diag[z′1,...,z′r]T，u′＝diag[u′1,...u′r]T， w′＝diag[w′1,...w′r]TAnd each iteration variable is obtained by updating the above formula. Mapping p ', q' to hyper-stereo space omega ═ betaminμ1 βmaxμ1]Obtain new vectors p and q, mu1The affine disturbance factor obtained in the step of predicting;
based on the above mapping, the center-correction direction Δ b is solved23And a total newton direction Δ b, expressed as:
Figure BDA0003228716960000161
Δb＝Δb1+Δb23
wherein n ═ p-p 'q-q']TAnd after obtaining the delta b, carrying out iterative solution as a conventional prime-dual interior point method.
Based on the system optimal power flow, the optimal control strategy of the TCPST can be formulated, the power supply capacity of the power grid is improved, meanwhile, the regulation and control capacity of the TCPST on the line power flow is fully exerted, and the operation safety of the power grid is further improved.
And selecting an IEEE14, IEEE30 and IEEE118 node system to perform simulation test so as to verify the effectiveness of the method. The upper and lower limits of the TCPST phase shift angle are set to be +30 degrees and-30 degrees, and affine step increment delta and beta are tested by a calculation examplemax、βminWhen the values are 0.65, 0.1 and 10 respectively, the MCCIPM has high iteration speed and good convergence.
According to the site selection principle, the TCPST should be installed on the key branch with the best optimization effect, and table 1 shows the best position for installing the TCPST of each system.
TABLE 1 basic parameters of the test System
Figure BDA0003228716960000162
Figure BDA0003228716960000171
To verify the correctness and validity of the improved MCCIPM algorithm in solving the OPF problem of the TCPST-containing system, table 2 shows a comparison of the PDIPM and the number of iterations of the improved MCCIPM algorithm to solve the OPF. Meanwhile, in order to verify that the TCPST has the capability of improving the system operation economy, OPF calculation is carried out on the TCPST system based on the method, and the comparison result of the system active network loss is shown in Table 2.
TABLE 2 comparison of OPF calculations
Figure BDA0003228716960000172
From the iteration times of the 2 algorithms, the iteration times of the PDIPM when OPF calculation is carried out on different systems are far higher than those of the improved MCCIPM; and as the system is increased, the PDIPM iteration times are obviously increased, and the phenomena of slow iterative computation of a large system, even no solution and the like are more likely to occur. MCCIPM is improved in an inverse mode, different systems can quickly converge in OPF calculation, and the iteration times are not greatly influenced by the size of the system.
In addition, the active network loss of the TCPST-containing system is obviously reduced compared with the original system, wherein the reduction ratios of the active network loss of the IEEE14 node system and the IEEE30 node system are larger and are respectively 14.29 percent and 29.03 percent, and the regulation effect is obvious; and the IEEE118 node system is large, only one controllable phase shifter is added, so that the reduction of the active network loss is not obvious and is only 3.85 percent.
The above analysis shows that the improved MCCIPM can effectively reduce the number of iterations and improve the OPF calculation efficiency, and still has good convergence in the large-system OPF calculation. Meanwhile, the active loss of system operation can be greatly reduced by adding the TCPST, and the stability and the economical efficiency of system operation can be better improved by considering increasing the number of TCPST equipment in a large system.
In order to verify the improvement effect of the TCPST on the power quality of the system, the different systems are subjected to example analysis. The extent to which the addition of TCPST affects the magnitude of the system node voltage is given in fig. 4, 5 and 6.
As can be seen from the comparison of the voltage amplitudes of the nodes in fig. 3, the voltage amplitude of the node 8 does not satisfy the safety constraint when the TCPST is not added to the system, and the voltage amplitude of the node satisfies the relevant requirements after the TCPST is added. If the voltage level of the system is described in a voltage qualified rate mode, the total voltage qualified rate of the IEEE14 node system is improved to 100% from 92.86% initially after the TCPST is added. In addition, the sum of the voltage offsets of each node of the system is 35.8% before the TCPST is installed; after the TCPST participates in the regulation, the sum of the voltage offsets is greatly reduced to 13.5%. After the IEEE30 system joins the TCPST, the sum of the voltage offsets of the nodes of the system is reduced from 131.9% to 122.1%. In the IEEE118 node system, only one TCPST is added without significant effect on the node voltage offset.
Simulation results show that the method has high efficiency and accuracy, and meanwhile, in small and medium-sized systems, the addition of TCPST reduces the active loss of the system, effectively reduces the voltage deviation of the node and improves the electric energy quality of the system; in order to better improve the electric energy quality of a large-scale system and improve the stability and the economy of the large-scale system, the installation quantity of the TCPSTs can be increased as appropriate, and the functions of controlling the power flow distribution, reducing the network loss of the system and the like of the TCPSTs are better exerted.
The software system corresponding to the method, namely the optimal power flow calculation system, comprises the following steps:
injecting a power model module: establishing a TCPST equivalent node injection power model under the original admittance matrix of the system on the basis of the real-time parameters of the system and the operation principle of the TCPST; wherein the system is a system comprising a TCPST;
an optimal power flow calculation model module: establishing a system optimal power flow calculation model considering the controllable phase shifter according to the TCPST equivalent node injection power model;
a solving module: and solving the system optimal power flow calculation model to obtain the system optimal power flow.
A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform an optimal power flow calculation optimization method.
A computing device comprising one or more processors, one or more memories, and one or more programs stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs including instructions for performing an optimal power flow calculation method.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the scope of the claims of the present invention which are filed as the application.

Claims (10)

1. An optimal power flow calculation method is characterized by comprising the following steps:
establishing a TCPST equivalent node injection power model under the original admittance matrix of the system on the basis of the real-time parameters of the system and the operation principle of the TCPST; wherein the system is a system comprising a TCPST;
establishing a system optimal power flow calculation model considering the controllable phase shifter according to the TCPST equivalent node injection power model;
and solving the system optimal power flow calculation model to obtain the system optimal power flow.
2. The optimal power flow calculation method according to claim 1, wherein the TCPST equivalent node injection power model is:
Figure FDA0003228716950000011
Figure FDA0003228716950000012
wherein, PTaInjecting active power, Q, for TCPST equivalent to node aTaEquivalent injection of reactive power, P, for TCPST to contact aTbInjecting active power, Q, for TCPST equivalent to contact bTbEquivalent injection of reactive power for TCPST to contact b, bRbThe equivalent susceptance of the branch in which the TCPST is located,
Figure FDA0003228716950000013
is the phase shift angle, U, of TCPSTaIs the voltage of node a, UbIs the voltage at the node b and is,
Figure FDA0003228716950000014
is the voltage angle difference between node R and node b of the branch where TCPST is located, babIs the equivalent susceptance of the lines a-b,
Figure FDA0003228716950000015
is the voltage angle difference between node a and node b.
3. The optimal power flow calculation method according to claim 1, wherein the system optimal power flow calculation model considering the controllable phase shifters comprises an objective function;
the method comprises the following specific steps:
Figure FDA0003228716950000021
wherein f is the active network loss of the system, n is the number of system nodes, and UiIs the voltage of node i, UjIs the voltage of node j, GijFor the i-j conductance, theta, of the lines in the system admittance matrixijIs the voltage phase angle difference between node i and node j.
4. The optimal power flow calculation method according to claim 1, wherein the system optimal power flow calculation model considering the controllable phase shifters comprises equality constraints;
the method comprises the following specific steps:
and (3) constraint of an equation:
Figure FDA0003228716950000022
wherein, PGiActive power, Q, generated for the generator on node iGiFor reactive power, P, generated by generators on node iDiIs the active load of node i, QDiBeing reactive load of node i, BijFor the line i-j susceptance, P, in the system admittance matrixTiIs a TCPST pairEquivalent injected active power, Q, of node iTiInjecting reactive power for TCPST to the equivalent of the contact point i, n is the number of system nodes, UiIs the voltage of node i, UjIs the voltage of node j, GijFor the i-j conductance, theta, of the lines in the system admittance matrixijIs the voltage phase angle difference between node i and node j.
5. The optimal power flow calculation method according to claim 1, wherein the system optimal power flow calculation model considering the controllable phase shifters comprises inequality constraints;
the method comprises the following specific steps:
TCPST capacity inequality constraint:
Figure FDA0003228716950000031
wherein, bRbIs the equivalent susceptance, g, of the branch in which the TCPST is locatedRbIs the equivalent conductance of the branch in which TCPST is located, is the conjugate, SmaxIn order to be the upper capacity limit of the TCPST,
Figure FDA0003228716950000032
for the TCPST series side voltage source voltage vector,
Figure FDA0003228716950000033
is a vector of the voltage at the node a,
Figure FDA0003228716950000034
is the voltage vector at node b;
TCPST tuning controls the inequality constraint:
Figure FDA0003228716950000035
wherein, UBFor TCPST series side voltage source voltage, thetaBFor the voltage phase angle, U, of the TCPST series side voltage sourceBmaxIs UBUpper limit of (U), UBminIs UBLower limit of (a), thetaBmaxIs thetaBUpper limit of (e), thetaBminIs thetaBThe lower limit of (d);
the remaining inequalities constrain:
Figure FDA0003228716950000036
wherein, UiIs the voltage of node i, UjIs the voltage of node j, UimaxIs UiUpper limit of (B), PGiActive power, Q, generated for the generator on node iGiReactive power, U, generated for generators on node iiminIs UiLower limit of (a), thetaiIs the voltage phase angle, θ, of node iimaxIs thetaiUpper limit of (e), thetaiminIs thetaiLower limit of (D), PijFor active power of lines i-j, QijFor reactive power of lines i-j, Pij,maxIs PijUpper limit of (B), Pij,minIs PijLower limit of (2), Qij,maxIs QijUpper limit of (2), Qij,minIs QijLower limit of (D), PGi,maxIs PGiUpper limit of (B), PGi,minIs PGiLower limit of (2), QGi,maxIs QGiUpper limit of (2), QGi,minIs QGiThe lower limit of (3).
6. The optimal power flow calculation method according to claim 1, wherein a system optimal power flow calculation model is solved to obtain a system optimal power flow, and the specific process is as follows:
and solving the system optimal power flow calculation model by adopting a multi-center-correction inner point method to obtain the system optimal power flow.
7. The optimal power flow calculation method according to claim 6, wherein the multi-center-correction interior point method is a modified multi-center-correction interior point method, and the modified multi-center-correction interior point method adjusts affine direction step length and hyper-stereo space mapping parameters based on a traditional multi-center-correction interior point method;
the adjusted affine direction step length is as follows:
α′＝min{max{αaf,αce,αco}+δ,1}
wherein alpha' is the adjusted affine direction step length, alphaafIs originally shot-like direction step length, alphaceStep size of center direction, αcoTo correct the direction step, δ is the affine direction step increment;
the adjusted hyper-stereo space mapping parameters are as follows:
δ∈[0.4,0.7]maximum value of spatial threshold βmax∈[5,8]Minimum value of spatial threshold βmin∈[0.4,0.6]。
8. An optimal power flow calculation system, comprising:
injecting a power model module: establishing a TCPST equivalent node injection power model under the original admittance matrix of the system on the basis of the real-time parameters of the system and the operation principle of the TCPST; wherein the system is a system comprising a TCPST;
an optimal power flow calculation model module: establishing a system optimal power flow calculation model considering the controllable phase shifter according to the TCPST equivalent node injection power model;
a solving module: and solving the system optimal power flow calculation model to obtain the system optimal power flow.
9. A computer readable storage medium storing one or more programs, characterized in that: the one or more programs include instructions that, when executed by a computing device, cause the computing device to perform any of the methods of claims 1-7.
10. A computing device, comprising:
one or more processors, one or more memories, and one or more programs stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods of claims 1-7.
CN202110979986.1A 2021-08-25 2021-08-25 Optimal power flow calculation method, system, storage medium and calculation equipment Pending CN113629717A (en)

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