Nothing Special   »   [go: up one dir, main page]

CN108599167B - Linear power flow calculation method for radial power distribution network - Google Patents

Linear power flow calculation method for radial power distribution network Download PDF

Info

Publication number
CN108599167B
CN108599167B CN201810035353.3A CN201810035353A CN108599167B CN 108599167 B CN108599167 B CN 108599167B CN 201810035353 A CN201810035353 A CN 201810035353A CN 108599167 B CN108599167 B CN 108599167B
Authority
CN
China
Prior art keywords
node
branch
equation
power
matrix
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201810035353.3A
Other languages
Chinese (zh)
Other versions
CN108599167A (en
Inventor
吴文传
高长征
张伯明
常学飞
杨越
刘座铭
高松
王佳蕊
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STATE GRID JILINSHENG ELECTRIC POWER SUPPLY Co ELECTRIC POWER RESEARCH INSTITUTE
Tsinghua University
State Grid Corp of China SGCC
Original Assignee
STATE GRID JILINSHENG ELECTRIC POWER SUPPLY Co ELECTRIC POWER RESEARCH INSTITUTE
Tsinghua University
State Grid Corp of China SGCC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by STATE GRID JILINSHENG ELECTRIC POWER SUPPLY Co ELECTRIC POWER RESEARCH INSTITUTE, Tsinghua University, State Grid Corp of China SGCC filed Critical STATE GRID JILINSHENG ELECTRIC POWER SUPPLY Co ELECTRIC POWER RESEARCH INSTITUTE
Priority to CN201810035353.3A priority Critical patent/CN108599167B/en
Publication of CN108599167A publication Critical patent/CN108599167A/en
Application granted granted Critical
Publication of CN108599167B publication Critical patent/CN108599167B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/04Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
    • H02J3/06Controlling transfer of power between connected networks; Controlling sharing of load between connected networks

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention relates to a linear power flow calculation method for a radial power distribution network, and belongs to the technical field of operation control of power systems. On the basis of a traditional linear equation without considering network loss and interphase mutual impedance, nonlinear network loss terms are linearly expanded and included in the equation, a linear three-phase branch power flow equation is established, and the active power load and the reactive power load of all nodes are utilized to calculate the approximate values of the active power, the reactive power and the voltage of all nodes of all branches, so that the power flow calculation result of the radial power distribution network is obtained. Compared with a linearized branch load flow equation without considering network loss, the method greatly improves the calculation precision, can directly obtain an approximate solution of the load flow without iterative solution, is rapid in calculation, and is suitable for being applied to scenes with strict performance requirements such as real-time online analysis of the power distribution network.

Description

Linear power flow calculation method for radial power distribution network
Technical Field
The invention relates to a linear power flow calculation method for a radial power distribution network, and belongs to the technical field of operation control of power systems.
Background
Compared with a transmission network, the power distribution network has the following remarkable characteristics:
1. essentially operating as a radial network, there is no annular loop.
2. The three-phase parameters of the line are asymmetric, the three-phase load of the node is unbalanced, and part of branches operate in a single-phase or double-phase state.
3. The branch resistance and the reactance are close to each other, and the PQ decoupling condition is not met.
Therefore, the characteristics need to be considered, and a power flow model which accords with the operation characteristics of the power distribution network is established.
Currently, a power flow algorithm suitable for a power distribution network has been proposed by a few scholars, such as a gaussian iteration method based on a three-phase extended node admittance matrix, a newton-raphson method and a previous generation back-substitution method using the radial operation characteristics of the power distribution network. Although the calculation efficiency of solving the power flow of the power distribution network by the prior generation back substitution method is quite high, the prior generation back substitution method still needs iterative solution, and in the problems of optimal power flow and the like, a power flow equation often appears in the problems as a non-convex equality constraint condition. To simplify the solution of the problem, it is necessary to convert the exact power flow equations into approximate simplified power flow equations. The existing literature provides a single-phase branch power flow equation based on the radial running characteristic of a power distribution network, and omits a network loss item to be used as a linear equation to solve.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a linear power flow calculation method of a radial power distribution network. The method selects a known tidal current state of a power grid as a reference point, approximates nonlinear terms in a tidal current equation by using parameters such as power and voltage of the reference point to obtain a linear three-phase tidal current equation, and rapidly obtains an approximate tidal current solution by solving the linear equation. The method has the advantages of high calculation speed and high result precision, and is suitable for being applied to scenes with harsh performance requirements, such as real-time online analysis of the power distribution network.
The invention provides a linearization power flow calculation method of a radial distribution network, which is characterized by comprising the following steps:
1) supposing that a radial distribution network to be subjected to load flow calculation has N +1 nodes, wherein the number of a root node is 0, starting from the root node, numbering the tail end nodes of each branch from 1 to N in sequence, and then, the number of the branches of the distribution network is N;
2) randomly selecting one node from nodes numbered from 1 to N as k, recording a branch formed by the node and an upstream node i as ik, and calculating a three-phase branch load flow equation of the node k and the branch ik; the method comprises the following specific steps:
2-1) calculate the voltage drop over branch ik:
Figure BDA0001547782400000021
wherein,
Figure BDA0001547782400000022
the expression points are divided, v, I and s are all in a three-dimensional column vector form and respectively represent voltage, current and power of three phases, subscript I represents the number of a head node of a branch ik, subscript k represents the number of a tail node of the branch ik, and x represents the conjugate of a complex number; v. ofkAnd viRespectively representing the voltages of node k and node I, IikCurrent, s, representing branch ikikRepresents the power of branch ik; z is a radical ofikIs a three-phase impedance matrix of branch ik, which is a 3 × 3 symmetric complex matrix:
Figure BDA0001547782400000023
wherein z isikThe diagonal elements of (1) represent self-impedance of a, b and c three phases, and the non-diagonal elements represent interphase mutual impedance;
conjugate two sides of the equal sign of the formula (1) and multiply the conjugate with the formula (1) to obtain:
Figure BDA0001547782400000024
2-2) considering node power balance, obtaining:
Figure BDA0001547782400000025
where the left side of the equation is the incoming power of node k, the right side of the equation is the sum of the outgoing powers of node k,
Figure BDA0001547782400000026
is the load of node k;
substituting formula (1) for formula (4) to obtain:
Figure BDA0001547782400000027
the three-phase branch load flow equation of the node k and the branch ik is formed by the formulas (1) and (5);
3) carrying out linear approximation on the three-phase branch load flow equation obtained in the step 2); the method comprises the following specific steps:
3-1) selecting a reference state, wherein
Figure BDA00015477824000000214
The voltage representing the reference state of node i,
Figure BDA0001547782400000028
and
Figure BDA0001547782400000029
respectively representing the active power of the branch ik reference state and the reactive power of the reference state;
3-2) voltage of reference state with node i
Figure BDA00015477824000000210
Approximation
Figure BDA00015477824000000211
Approximation of equation (1):
Figure BDA00015477824000000212
for the first two terms on the right of the equal sign of formula (6), define
Figure BDA00015477824000000213
Obtaining:
Figure BDA0001547782400000031
wherein p isik,qikRespectively representing the active and reactive power of branch ik,
Figure BDA0001547782400000032
is a calculated auxiliary variable;
for the third term on the right of equation (6), define
Figure BDA0001547782400000033
diag denotes the conversion of a vector into a diagonal matrix,
Figure BDA0001547782400000034
are all calculated auxiliary variables, resulting in:
Figure BDA0001547782400000035
to the right of formula (8) is with respect to pikAnd q isikA quadratic function of
Figure BDA0001547782400000036
The first-order Taylor expansion is carried out and converted into a linear function:
Figure BDA0001547782400000037
further written in the form:
Figure BDA0001547782400000038
wherein R isik,XikIs a 3 x 3 matrix of the matrix,
Figure BDA0001547782400000039
is a 3 × 1 vector, and takes the following value:
Figure BDA00015477824000000310
3-3) voltage of reference state with node i
Figure BDA0001547782400000041
Approximation
Figure BDA0001547782400000042
Approximation of equation (5):
Figure BDA0001547782400000043
the second term on the left of equation (12) is written as:
Figure BDA0001547782400000044
order to
Figure BDA0001547782400000045
Are all calculated auxiliary variables, resulting in:
Figure BDA0001547782400000046
writing the real part and the imaginary part separately into the forms of active power and reactive power:
Figure BDA0001547782400000047
in equation (15), the first equation represents the active power balance of node k, the second equation represents the reactive power balance of node k, pik、pkmThe active power of the branches ik and km, qik、qkmThe reactive powers of the branches ik and km respectively, and the node m is a downstream node of the node k;
Figure BDA0001547782400000048
is the active load of the node k and,
Figure BDA0001547782400000049
is the reactive load of node k; f. ofp(pik,qik) And fq(pik,qik) Respectively as follows:
Figure BDA00015477824000000410
Figure BDA00015477824000000411
fp(pik,qik) And fq(pik,qik) Are all about pikAnd q isikOf a quadratic function of
Figure BDA00015477824000000412
And (3) performing first-order Taylor expansion, and converting into a linear function:
Figure BDA00015477824000000413
Figure BDA0001547782400000051
equation (15) is written as follows:
Figure BDA0001547782400000052
wherein B isik,Gik,Hik,KikIs a 3 x 3 matrix of the matrix,
Figure BDA0001547782400000053
is a 3 × 1 vector, and takes the following value:
Figure BDA0001547782400000054
after conversion, the equations (10) and (20) form a linearized three-phase branch load flow equation of the node k and the branch ik;
4) repeating the step 2) to the step 3) to obtain a linearized three-phase branch flow equation of all nodes of the power distribution network except the root node and corresponding branches taking the nodes as tail end nodes;
5) converting all the linearized three-phase branch load flow equations obtained in the step 4) into a matrix form to obtain a power distribution network load flow calculation result;
the expression of the linearized three-phase branch load flow equation in the form of a matrix is as follows:
Figure BDA0001547782400000055
Figure BDA0001547782400000056
Figure BDA0001547782400000057
solving a linear equation set composed of the formulas (22) to (24) to obtain the active power p of the branchbReactive power qbBranch voltage difference ubAnd node voltage unThe expression of (1) is as follows, wherein subscript b represents all branch sets, and subscript n represents all node sets;
Figure BDA0001547782400000061
Figure BDA0001547782400000062
wherein M is a three-phase extended node branch incidence matrix, and N ispRepresenting a network incidence matrix, Rb,Xb,Bb,Gb,Hb,KbRespectively representing R corresponding to each branchik,Xik,Bik,Gik,Hik,KikThe extension forms which are arranged along the main diagonal of the matrix according to the serial number sequence of the branch tail end nodes are all 3 Nx3N matrixes;
Figure BDA0001547782400000063
respectively indicating that each branch corresponds to
Figure BDA0001547782400000064
The extension forms arranged according to the serial number sequence of the branch ends are vectors of 3 Nx 1;
inputting the active power load p of all nodes by the equation (25)LAnd reactive power load qLCalculating the active power p of all branchesbReactive power qbAll node voltages unAnd obtaining the load flow calculation result of the radial distribution network.
The method has the characteristics and beneficial effects that:
in order to improve the accuracy of a linearized three-phase power flow equation, the invention provides a novel linearized approximation method, and a nonlinear network loss term is linearly expanded and included in the equation on the basis of a traditional linear equation without considering network loss and phase mutual impedance. As long as a proper reference load flow state is selected, the method can perform quite accurate estimation on the network loss, the accuracy of a calculation result is obviously higher than that of a simple linear equation, the advantages of a linear model are maintained, iterative solution is not needed, and the calculation speed is high.
The method starts from an accurate branch power flow equation, the voltage in the equation is replaced by the voltage in a reference state, the secondary power term is subjected to first-order Taylor expansion linearization at the power of a reference point, and no other approximation or some term is removed. Therefore, the accuracy of the power flow equation only depends on the selection of the datum point and is not influenced by the three-phase imbalance degree. The application of the method in the practical power distribution network calculation example shows that the result provided by the method is high in precision and the precision is related to the selected reference state, when the precise power flow solution is selected as the reference state, the precise solution is obtained, and even if the non-precise power flow solution is selected as the reference state, the error is far smaller than the linearized branch power flow equation without considering the network loss. Meanwhile, the method does not need iterative solution, is rapid in calculation, and is suitable for being applied to scenes with harsh performance requirements, such as real-time online analysis of the power distribution network.
Drawings
FIG. 1 is a block diagram of the overall flow of the method of the present invention.
Fig. 2 is a schematic power flow diagram of a radial distribution network in accordance with an embodiment of the present invention.
Detailed Description
The invention provides a linearized power flow calculation method for a radial distribution network, which is further described in detail below with reference to the accompanying drawings and specific embodiments.
The invention provides a linearization power flow calculation method of a radial distribution network, aiming at the network characteristics of radial operation and three-phase unbalance of the distribution network, the overall flow is shown in figure 1, and the linearization power flow calculation method comprises the following steps:
1) supposing that a radial distribution network to be subjected to load flow calculation has N +1 nodes, wherein the number of a root node is 0, starting from the root node, numbering the tail end nodes of each branch from 1 to N in sequence, and then, the number of the branches of the distribution network is N;
2) randomly selecting one node from nodes numbered from 1 to N as k, recording a branch formed by the node and an upstream node i as ik, and calculating a three-phase branch load flow equation of the node k and the branch ik;
taking the trend of node k and branch ik as shown in fig. 2 as an example, node i is an upstream node of node k (i.e., node i is closer to the root node than node k, and there is only one upstream node in each node in the radial grid, (if the selected node is numbered 1. then the upstream node is the root node, the same method is also adopted for calculation), and node m is a downstream node of node k (there may be more than one downstream node of each node, and any one downstream node m is taken as an illustration here).
The method comprises the following specific steps:
2-1) calculate the voltage drop over branch ik:
Figure BDA0001547782400000071
wherein,
Figure BDA0001547782400000072
the notation dot division, v, I and s are all in the form of three-dimensional column vectors representing the voltage, current and power of the three phases, respectively, with subscript I representing the number of the leading node of branch ik, subscript k representing the number of the trailing node of branch ik, and x representing the conjugate of the complex number. v. ofkAnd viRespectively representing the voltages of node k and node I, IikCurrent, s, representing branch ikikRepresenting the power of branch ik. z is a radical ofikIs a three-phase impedance matrix of branch ik, which is a 3 × 3 symmetric complex matrix:
Figure BDA0001547782400000073
wherein z isikThe diagonal elements of (a) represent the self-impedance of the three phases a, b and c, and the non-diagonal elements represent the interphase mutual impedance.
Conjugate two sides of the equal sign of the formula (1) and multiply the conjugate with the formula (1) to obtain:
Figure BDA0001547782400000074
2-2) considering node power balance, obtaining:
Figure BDA0001547782400000075
where the left side of the equation is the incoming power of node k, equationThe right side is the sum of the outgoing powers of node k,
Figure BDA0001547782400000076
is the load of node k.
Substituting formula (1) for formula (4) to obtain:
Figure BDA0001547782400000081
the three-phase branch power flow equation of the node k and the branch ik is formed by the formulas (1) and (5). Compared with the single-phase branch load flow equation, the mathematical form of the three-phase branch load flow equation is more complicated due to the interphase coupling.
3) Carrying out linear approximation on the three-phase branch load flow equation obtained in the step 2); the method comprises the following specific steps:
3-1) for a linearized approximation, a reference state is selected, which includes values of branch power and node voltage, and the result of the state estimation can be generally selected as the reference state, whose value is denoted by the superscript 0 in the following derivation, including:
Figure BDA0001547782400000082
the voltage representing the reference state of node i,
Figure BDA0001547782400000083
and
Figure BDA0001547782400000084
respectively representing the active power of the branch ik reference state and the reactive power of the reference state;
3-2) approximating the equation (1), the voltage per unit of the actual power grid is about 1, so the voltage of the state is referred to by the node i
Figure BDA0001547782400000085
Approximation
Figure BDA0001547782400000086
Figure BDA0001547782400000087
For the first two terms on the right of the equal sign of formula (6), define
Figure BDA0001547782400000088
Obtaining:
Figure BDA0001547782400000089
wherein p isik,qikRespectively representing the active and reactive power of branch ik,
Figure BDA00015477824000000810
are all calculated auxiliary variables.
For the third term on the right of equation (6), define
Figure BDA00015477824000000811
diag denotes the conversion of a vector into a diagonal matrix,
Figure BDA00015477824000000812
are all calculated auxiliary variables, resulting in:
Figure BDA00015477824000000813
wherein
Figure BDA00015477824000000814
Respectively, the active power and the reactive power of the branch ik reference state.
To the right of formula (8) is with respect to pikAnd q isikA quadratic function of
Figure BDA00015477824000000815
The first-order Taylor expansion is carried out and converted into a linear function:
Figure BDA0001547782400000091
further written in the form:
Figure BDA0001547782400000092
wherein R isik,XikIs a 3 x 3 matrix of the matrix,
Figure BDA0001547782400000093
is a 3 × 1 vector, and takes the following value:
Figure BDA0001547782400000094
3-3) voltage of reference state with node i
Figure BDA0001547782400000095
Approximation
Figure BDA0001547782400000096
Approximation of equation (5):
Figure BDA0001547782400000097
the second term on the left of equation (12) is written as:
Figure BDA0001547782400000098
order to
Figure BDA0001547782400000099
Figure BDA00015477824000000910
Are all calculated auxiliary variables, resulting in:
Figure BDA00015477824000000911
writing the real part and the imaginary part separately into the forms of active power and reactive power:
Figure BDA0001547782400000101
in equation (15), the first equation represents the active power balance of node k, the second equation represents the reactive power balance of node k, pik、pkmThe active power of the branches ik and km, qik、qkmThe reactive powers of the branches ik and km respectively, and the node m is a downstream node of the node k;
Figure BDA0001547782400000102
is the active load of the node k and,
Figure BDA0001547782400000103
is the reactive load of node k. f. ofp(pik,qik) And fq(pik,qik) Respectively as follows:
Figure BDA0001547782400000104
Figure BDA0001547782400000105
fp(pik,qik) And fq(pik,qik) Are all about pikAnd q isikOf a quadratic function of
Figure BDA0001547782400000106
And (3) performing first-order Taylor expansion, and converting into a linear function:
Figure BDA0001547782400000107
Figure BDA0001547782400000108
after work-up, formula (15) is written as follows:
Figure BDA0001547782400000109
wherein B isik,Gik,Hik,KikIs a 3 x 3 matrix of the matrix,
Figure BDA00015477824000001010
is a 3 × 1 vector, and takes the following value:
Figure BDA0001547782400000111
after transformation, equations (10) and (20) constitute a linearized three-phase branch power flow equation for node k and branch ik.
4) And (4) repeating the steps 2) to 3) to obtain the linearized three-phase branch flow equation of all the nodes of the power distribution network except the root node and the corresponding branches taking the nodes as the tail end nodes.
5) Converting all the linearized three-phase branch load flow equations obtained in the step 4) into a matrix form to obtain a power distribution network load flow calculation result;
the expression of the linearized three-phase branch load flow equation in the form of a matrix is as follows:
Figure BDA0001547782400000112
Figure BDA0001547782400000113
Figure BDA0001547782400000114
solving the linear equation set composed of the equations (22) to (24) can be achieved by using linear algebra software such as MATLAB and the like to obtain the active power p of the branchb(subscript b represents the set of all branches), reactive power qbAm, amDifference u of the path voltagebNode voltage un(subscript n represents the set of all nodes) the explicit expression is as follows, it can be seen that the node load p isLAnd q isLLinear form of (a).
Figure BDA0001547782400000115
Figure BDA0001547782400000116
Wherein M is a three-phase extended node branch incidence matrix, and N ispRepresenting the network incidence matrix (these two matrices can be written directly according to the power grid topology), Rb,Xb,Bb,Gb,Hb,KbRespectively representing R corresponding to each branchik,Xik,Bik,Gik,Hik,KikThe expansion forms arranged along the main diagonal of the matrix according to the numbering sequence of the branch end nodes are all 3 Nx3N matrixes.
Figure BDA0001547782400000117
Respectively indicating that each branch corresponds to
Figure BDA0001547782400000118
The extension forms arranged according to the numbering sequence of the branch ends are vectors of 3 Nx 1.
Inputting the active power load p of all nodes by the equation (25)LAnd reactive power load qLBy performing matrix operation, all branch active power p can be directly obtainedbReactive power qbAll node voltages unAnd obtaining the load flow calculation result of the radial distribution network.

Claims (1)

1. A linearization power flow calculation method of a radial distribution network is characterized by comprising the following steps:
1) supposing that a radial distribution network to be subjected to load flow calculation has N +1 nodes, wherein the number of a root node is 0, starting from the root node, numbering the tail end nodes of each branch from 1 to N in sequence, and then, the number of the branches of the distribution network is N;
2) randomly selecting one node from nodes numbered from 1 to N as k, recording a branch formed by the node and an upstream node i as ik, and calculating a three-phase branch load flow equation of the node k and the branch ik; the method comprises the following specific steps:
2-1) calculate the voltage drop over branch ik:
Figure FDA0001547782390000011
wherein,
Figure FDA0001547782390000012
the expression points are divided, v, I and s are all in a three-dimensional column vector form and respectively represent voltage, current and power of three phases, subscript I represents the number of a head node of a branch ik, subscript k represents the number of a tail node of the branch ik, and x represents the conjugate of a complex number; v. ofkAnd viRespectively representing the voltages of node k and node I, IikCurrent, s, representing branch ikikRepresents the power of branch ik; z is a radical ofikIs a three-phase impedance matrix of branch ik, which is a 3 × 3 symmetric complex matrix:
Figure FDA0001547782390000013
wherein z isikThe diagonal elements of (1) represent self-impedance of a, b and c three phases, and the non-diagonal elements represent interphase mutual impedance;
conjugate two sides of the equal sign of the formula (1) and multiply the conjugate with the formula (1) to obtain:
Figure FDA0001547782390000014
2-2) considering node power balance, obtaining:
Figure FDA0001547782390000015
where the left side of the equation is the incoming power of node k, the right side of the equation is the sum of the outgoing powers of node k,
Figure FDA0001547782390000016
is the load of node k;
substituting formula (1) for formula (4) to obtain:
Figure FDA0001547782390000017
the three-phase branch load flow equation of the node k and the branch ik is formed by the formulas (1) and (5);
3) carrying out linear approximation on the three-phase branch load flow equation obtained in the step 2); the method comprises the following specific steps:
3-1) selecting a reference state, wherein
Figure FDA0001547782390000018
The voltage representing the reference state of node i,
Figure FDA0001547782390000019
and
Figure FDA00015477823900000110
respectively representing the active power of the branch ik reference state and the reactive power of the reference state;
3-2) voltage of reference state with node i
Figure FDA00015477823900000111
Approximation
Figure FDA00015477823900000112
Approximation of equation (1):
Figure FDA0001547782390000021
for the first two terms on the right of the equal sign of formula (6), define
Figure FDA0001547782390000022
Obtaining:
Figure FDA0001547782390000023
wherein p isik,qikRespectively representing the active and reactive power of branch ik,
Figure FDA0001547782390000024
is a calculated auxiliary variable;
for the third term on the right of equation (6), define
Figure FDA0001547782390000025
diag denotes the conversion of a vector into a diagonal matrix,
Figure FDA0001547782390000026
are all calculated auxiliary variables, resulting in:
Figure FDA0001547782390000027
to the right of formula (8) is with respect to pikAnd q isikA quadratic function of
Figure FDA0001547782390000028
The first-order Taylor expansion is carried out and converted into a linear function:
Figure FDA0001547782390000029
further written in the form:
Figure FDA00015477823900000210
wherein R isik,XikIs a 3 x 3 matrix of the matrix,
Figure FDA00015477823900000211
is a 3 × 1 vector, and takes the following value:
Figure FDA0001547782390000031
3-3) voltage of reference state with node i
Figure FDA0001547782390000032
Approximation
Figure FDA0001547782390000033
Approximation of equation (5):
Figure FDA0001547782390000034
the second term on the left of equation (12) is written as:
Figure FDA0001547782390000035
order to
Figure FDA0001547782390000036
Figure FDA0001547782390000037
Are all calculated auxiliary variables, resulting in:
Figure FDA0001547782390000038
writing the real part and the imaginary part separately into the forms of active power and reactive power:
Figure FDA0001547782390000039
in equation (15), the first equation represents the active power balance of node k, the second equation represents the reactive power balance of node k, pik、pkmThe active power of the branches ik and km, qik、qkmThe reactive powers of the branches ik and km respectively, and the node m is a downstream node of the node k;
Figure FDA00015477823900000310
is the active load of the node k and,
Figure FDA00015477823900000311
is the reactive load of node k; f. ofp(pik,qik) And fq(pik,qik) Respectively as follows:
Figure FDA00015477823900000312
Figure FDA00015477823900000313
fp(pik,qik) And fq(pik,qik) Are all about pikAnd q isikOf a quadratic function of
Figure FDA0001547782390000041
And (3) performing first-order Taylor expansion, and converting into a linear function:
Figure FDA0001547782390000042
Figure FDA0001547782390000043
equation (15) is written as follows:
Figure FDA0001547782390000044
wherein B isik,Gik,Hik,KikIs a 3 x 3 matrix of the matrix,
Figure FDA0001547782390000045
is a 3 × 1 vector, and takes the following value:
Figure FDA0001547782390000046
after conversion, the equations (10) and (20) form a linearized three-phase branch load flow equation of the node k and the branch ik;
4) repeating the step 2) to the step 3) to obtain a linearized three-phase branch flow equation of all nodes of the power distribution network except the root node and corresponding branches taking the nodes as tail end nodes;
5) converting all the linearized three-phase branch load flow equations obtained in the step 4) into a matrix form to obtain a power distribution network load flow calculation result;
the expression of the linearized three-phase branch load flow equation in the form of a matrix is as follows:
Figure FDA0001547782390000047
Figure FDA0001547782390000048
Figure FDA0001547782390000051
solving a linear equation set composed of the formulas (22) to (24) to obtain the active power p of the branchbReactive power qbBranch voltage difference ubAnd node voltage unWherein subscript b represents all branch sets and subscript n representsThere is a set of nodes;
Figure FDA0001547782390000052
Figure FDA0001547782390000053
wherein M is a three-phase extended node branch incidence matrix, and N ispRepresenting a network incidence matrix, Rb,Xb,Bb,Gb,Hb,KbRespectively representing R corresponding to each branchik,Xik,Bik,Gik,Hik,KikThe extension forms which are arranged along the main diagonal of the matrix according to the serial number sequence of the branch tail end nodes are all 3 Nx3N matrixes;
Figure FDA0001547782390000054
respectively indicating that each branch corresponds to
Figure FDA0001547782390000055
The extension forms arranged according to the serial number sequence of the branch ends are vectors of 3 Nx 1;
inputting the active power load p of all nodes by the equation (25)LAnd reactive power load qLCalculating the active power p of all branchesbReactive power qbAll node voltages unAnd obtaining the load flow calculation result of the radial distribution network.
CN201810035353.3A 2018-01-15 2018-01-15 Linear power flow calculation method for radial power distribution network Active CN108599167B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810035353.3A CN108599167B (en) 2018-01-15 2018-01-15 Linear power flow calculation method for radial power distribution network

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810035353.3A CN108599167B (en) 2018-01-15 2018-01-15 Linear power flow calculation method for radial power distribution network

Publications (2)

Publication Number Publication Date
CN108599167A CN108599167A (en) 2018-09-28
CN108599167B true CN108599167B (en) 2020-10-20

Family

ID=63608342

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810035353.3A Active CN108599167B (en) 2018-01-15 2018-01-15 Linear power flow calculation method for radial power distribution network

Country Status (1)

Country Link
CN (1) CN108599167B (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109980650B (en) * 2019-05-21 2022-11-15 华北水利水电大学 Load flow calculation method of radiation type power distribution system
CN110568265A (en) * 2019-10-17 2019-12-13 江苏远致能源科技有限公司 Impedance identification method and system based on low-voltage distribution network
CN112542838B (en) * 2020-11-26 2023-01-03 云南电网有限责任公司 Three-phase power flow linearization method for power distribution network based on support vector regression
CN114221344A (en) * 2021-11-05 2022-03-22 三峡大学 Improved affine algorithm-based forward-backward substitution load flow calculation method
CN114566971B (en) * 2022-03-01 2024-09-24 东北大学秦皇岛分校 Real-time optimal power flow calculation method based on near-end strategy optimization algorithm

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104734153A (en) * 2014-12-18 2015-06-24 国家电网公司 Method of reconstructing power distribution network containing distributed power supply
WO2015073270A3 (en) * 2013-11-14 2015-07-23 Abb Technology Ag Method and apparatus for security constrained economic dispatch in hybrid power systems
CN106446458A (en) * 2016-11-01 2017-02-22 国网技术学院 Weakly looped power distribution network load flow calculation method considering distributed power supplies
CN106532709A (en) * 2016-10-25 2017-03-22 天津大学 Distribution-grid-reconstruction-based optimal power flow calculation method for integrated communication energy system
CN107069741A (en) * 2017-04-20 2017-08-18 河海大学 A kind of novel linear tidal current computing method
CN107482633A (en) * 2017-08-22 2017-12-15 东南大学 A kind of non-iterative Interval Power Flow algorithm suitable for radial distribution networks

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015073270A3 (en) * 2013-11-14 2015-07-23 Abb Technology Ag Method and apparatus for security constrained economic dispatch in hybrid power systems
CN104734153A (en) * 2014-12-18 2015-06-24 国家电网公司 Method of reconstructing power distribution network containing distributed power supply
CN106532709A (en) * 2016-10-25 2017-03-22 天津大学 Distribution-grid-reconstruction-based optimal power flow calculation method for integrated communication energy system
CN106446458A (en) * 2016-11-01 2017-02-22 国网技术学院 Weakly looped power distribution network load flow calculation method considering distributed power supplies
CN107069741A (en) * 2017-04-20 2017-08-18 河海大学 A kind of novel linear tidal current computing method
CN107482633A (en) * 2017-08-22 2017-12-15 东南大学 A kind of non-iterative Interval Power Flow algorithm suitable for radial distribution networks

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
两种配电网线性潮流计算方法及其比较;敖鑫等;《电网技术》;20171231;第41卷(第12期);全文 *
配电网潮流计算的分析与运用;叶帆;《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》;20160215;全文 *

Also Published As

Publication number Publication date
CN108599167A (en) 2018-09-28

Similar Documents

Publication Publication Date Title
CN108599167B (en) Linear power flow calculation method for radial power distribution network
Padrón et al. Calculating steady-state operating conditions for doubly-fed induction generator wind turbines
CN107959294B (en) Power distribution network sensitivity calculation method based on linearized power flow
CN104462661B (en) Electronic power switch interpolation real-time emulation method
CN108875269B (en) Multi-period energy flow calculation method of electricity-gas interconnection system considering slow dynamic characteristics of multi-balancing machine of power system and natural gas system
CN102879668A (en) Asymmetric fault analysis method for power distribution network including inverted distribution type power supply
CN105184027B (en) A kind of power load modelling approach based on interacting multiple model algorithm
CN103984822A (en) Three phase flow implementation method based on advanced digital power system simulator
CN101976837A (en) Method for adjusting unsolvable power flow of electric power system
CN100470995C (en) Distributed computing method of the features of the power system
WO2018102720A1 (en) System and method for a fast power network simulator
CN108075478B (en) Transient stability emergency control method
CN107104430A (en) A kind of bilingual coupling method for estimating state of power distribution network
CN110912137A (en) Flexible power distribution network operation domain model construction method considering alternating current power flow
CN105305392B (en) Short circuit calculation symmetrical component method suitable for the type IIDG power distribution network of control containing voltage
CN110048428B (en) Power system probability load flow calculation method based on probability conservation principle
CN108596475B (en) PMU data recovery method based on dynamic change of interpolation interval
CN107658880B (en) The algorithm quicksort coefficient matrix calculation method of operation based on correlation matrix
CN111045329B (en) Double-fed fan digital physical hybrid simulation method based on self-adaptive mode switching
CN103928941B (en) Analytic solving method for generator aggregation
Blaauwbroek et al. Branch current state estimation of three phase distribution networks suitable for paralellization
Nicholson Hierarchical control of a multimachine power system model
CN105005831B (en) A kind of calculation method of the quasi- direct current Dynamic Optimal Power Flow Problem based on electric power system tide coupled relation
Oyedokun et al. Analysis and Compensation of Power Systems with Harmonics and Unbalance
CN111541266B (en) Load flow calculation method of power distribution system with distributed power supply based on forward-backward substitution idea

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant