CN109755942A - Extension trend method and device based on optimization method - Google Patents
Extension trend method and device based on optimization method Download PDFInfo
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Abstract
The extension trend method and device based on optimization method that the invention discloses a kind of, wherein method includes: to limit equation according to the busbar voltage that limitation formula establishes relaxation；The tide optimization problem for having partial voltage control device is established by optimization formula；The Optimized model, the Optimized model of PV bus and the Optimized model of PQ bus of zero injection bus are established by constraint equation；Optimized model, the Optimized model of PV bus and the Optimized model of PQ bus of zero injection bus are solved by the IPM of constant Hessian matrix, to obtain integer tap position, and carry out functional test under the conditions of three-phase equilibrium and imbalance.The convergence of nonlinear-sensitivity method under fully loaded transportation condition can be improved in this method, suitable for infeasible voltage limitation is detected and relaxed under fully loaded transportation condition, it is ensured that Power flow solvability.
Description
Technical Field
The invention relates to the technical field of power system expanded power flow, in particular to an expanded power flow method and device based on an optimization method.
Background
The local voltage controllers are addressed by a sensitivity-based approach in the related art that applies a constant impedance matrix to derive a nonlinear sensitivity matrix for the local voltage controllers. Due to the fact that the nonlinearity of the power flow is serious under the heavy load condition, the distributed network power flow which is based on the sensitivity method and corresponds to the local voltage controller needs more iteration times under the heavy load condition.
The nonlinear sensitivity matrix of the voltage control distributed generator can also be derived based on loop analysis, which proves that the nonlinear sensitivity method has better convergence than the linear sensitivity method, however, under heavy load, the nonlinear sensitivity method may have poor convergence, and particularly after the position of the tap switch is adjusted under heavy load, the bus voltage may still exceed the voltage limit, which is needed to be solved urgently.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, an object of the present invention is to provide an optimization-based method for expanding power flow, which can improve the convergence of the nonlinear sensitivity method under a heavy load condition, and is suitable for detecting and relaxing the infeasible voltage limitation under the heavy load condition.
Another objective of the present invention is to provide an expanded power flow device based on the optimization method.
In order to achieve the above object, an embodiment of the present invention provides an expanded trend method based on an optimization method, including the following steps: establishing a relaxed bus voltage limit equation according to a limit formula; establishing a power flow optimization problem with a local voltage controller through an optimization formula; establishing an optimization model of a zero injection bus, an optimization model of a PV bus and an optimization model of a PQ bus through a constraint equation; and solving the optimization model of the zero injection bus, the optimization model of the PV bus and the optimization model of the PQ bus through an IPM (Intelligent Power Module) of a constant blackplug matrix to obtain an integer tap position, and performing functional test under the conditions of three-phase balance and unbalance.
According to the power flow expanding method based on the optimization method, the IPM of the constant blackplug matrix is used for solving the optimization model of the zero injection bus, the optimization model of the PV bus and the optimization model of the PQ bus, so that the integer tap position is obtained, the function test is carried out under the conditions of three-phase balance and unbalance, the purpose of power flow expanding based on the optimization method is achieved, the problem that the non-linearity problem of distributed network power flow of a local voltage controller is solved based on a sensitive method under the heavy load condition, the problem that the limitation of the non-feasible voltage is detected and relaxed under the heavy load condition is solved, the convergence of the non-linear sensitivity method under the heavy load condition is improved, and the method is suitable for detecting and relaxing the limitation of the non-feasible voltage under the heavy load condition.
In addition, the expanded trend method based on the optimization method according to the above embodiment of the present invention may further have the following additional technical features:
further, in one embodiment of the present invention, the bus voltage limit equation is established by a limit formula, the limit formula being:
wherein,the lower limit of the square of the bus voltage,for the upper limit of the square of the bus voltage, l and U represent non-negative relaxation variables, UreAnd UimRespectively a real part and an imaginary part of a bus voltage complex variable; guIs the upper limit of the function, g is the mapping, glFor the lower limit of the function,is the bus voltage squared.
Further, in an embodiment of the present invention, the trend optimization problem is established by the following optimization formula:
min∑(u+v)
wherein t is the position of the transformer tap, tminAnd tmaxThe minimum value limit and the maximum value limit of the transformer tap position are respectively, h is mapping, v is a non-negative relaxation variable, and s.t. is a constraint condition.
Further, in an embodiment of the present invention, the establishing an optimization model of a zero injection bus, an optimization model of a PV bus, and an optimization model of a PQ bus further includes:
for the zero injection bus, the first constraint equation h is expressed as a pair of linear equations:
wherein, IreAnd IimRespectively the real and imaginary part of the injected current, YzeroFor the admittance row corresponding to the zero injection bus, U is the complex bus voltage,andthe real and imaginary parts of the equation, respectively.
For the PV bus, a second constraint equation h is expressed in pairs as:
wherein,for the voltage control target of the PV bus, the subscript PV is the corresponding vector or matrix row of the PV bus, diag is the diagonal matrix, the conjugate of the complex variable, SreIn order to inject the real part of the complex power,is the real part of the equation, YPVFor admittance rows corresponding to PQ bus-bars, UPVIs the PV bus voltage, U is the complex bus voltage,is the real part of the PV bus voltage squared,the imaginary part of the PV bus voltage squared.
For the PQ bus, the third constraint equation h is expressed in pairs as:
wherein S isreAnd SimRespectively the real and imaginary parts of the injected complex power,andreal and imaginary parts of the equation, diag is the diagonal matrix, conjugate of complex variable, subscript PQ is the corresponding vector or matrix row of PQ bus, UPQIs PQ bus voltage, YPQU is the complex bus voltage for the admittance row corresponding to the PQ bus.
Further, in one embodiment of the present invention, the integer tap positions are obtained by rounding the fractional values of the tap positions.
In order to achieve the above object, an embodiment of another aspect of the present invention provides an expanded power flow device based on an optimization method, including: the limiting equation establishing module is used for establishing a relaxed bus voltage limiting equation according to a limiting formula; the optimization problem establishing module is used for establishing a power flow optimization problem with a local voltage controller through an optimization formula; the optimization model establishing module is used for establishing an optimization model of the zero injection bus, an optimization model of the PV bus and an optimization model of the PQ bus through a constraint equation; and the power flow expansion module is used for solving the optimization model of the zero injection bus, the optimization model of the PV bus and the optimization model of the PQ bus through IPM of the constant black plug matrix to obtain an integer tap position, and performing functional test under three-phase balance and unbalance conditions.
According to the expanded power flow device based on the optimization method, the IPM of the constant blackplug matrix is used for solving the optimization model of the zero injection bus, the optimization model of the PV bus and the optimization model of the PQ bus, so that the integer tap position is obtained, the function test is carried out under the conditions of three-phase balance and unbalance, the purpose of expanding the power flow based on the optimization method is achieved, the problem that the distributed network power flow of a local voltage controller is non-linear under the heavy load condition based on a sensitive method and the problem that the infeasible voltage limitation is detected and relaxed under the heavy load condition are solved, the convergence of the non-linear sensitivity method under the heavy load condition is improved, and the expanded power flow device is suitable for detecting and relaxing the infeasible voltage limitation under the heavy load condition.
In addition, the expanded power flow device based on the optimization method according to the above embodiment of the present invention may further have the following additional technical features:
further, in one embodiment of the present invention, the restriction equation in the restriction equation establishing module is:
wherein,the lower limit of the square of the bus voltage,for the upper limit of the square of the bus voltage, l and U are respectively non-negative relaxation variables, UreAnd UimReal and imaginary parts, g, of complex variables of the bus voltage, respectivelyuIs the upper limit of the function, g is the mapping, glFor the lower limit of the function,is the bus voltage squared.
Further, in an embodiment of the present invention, the optimization formula in the optimization problem establishing module is:
min∑(u+v)
wherein t is the position of the transformer tap, tminAnd tmaxThe minimum value limit and the maximum value limit of the transformer tap position are respectively, h is mapping, v is a non-negative relaxation variable, and s.t. is a constraint condition.
Further, in an embodiment of the present invention, the optimization model building module further includes:
for the zero injection bus, the first constraint equation h is expressed as a pair of linear equations:
wherein, IreAnd IimRespectively the real and imaginary part of the injected current, YzeroFor the admittance row corresponding to the zero injection bus, U is the complex bus voltage,andthe real and imaginary parts of the equation, respectively.
For the PV bus, a second constraint equation h is expressed in pairs as:
wherein,for the voltage control target of the PV bus, the subscript PV is the corresponding vector or matrix row of the PV bus, diag is the diagonal matrix, the conjugate of the complex variable, SreIn order to inject the real part of the complex power,is the real part of the equation, YPVFor admittance rows corresponding to PV bus-bars, UPVIs the PV bus voltage, U is the complex bus voltage,is the real part of the PV bus voltage squared,the imaginary part of the PV bus voltage squared.
For the PQ bus, the third constraint equation h is expressed in pairs as:
wherein S isreAnd SimRespectively the real and imaginary parts of the injected complex power,andreal and imaginary parts of the equation, diag is the diagonal matrix, conjugate of complex variable, subscript PQ is the corresponding vector or matrix row of PQ bus, UPQIs PQ bus voltage, YPQU is the complex bus voltage for the admittance column corresponding to the PQ bus voltage.
Further, in one embodiment of the present invention, the integer tap positions are obtained by rounding the fractional values of the tap positions.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a flow chart of an extended power flow method based on an optimization method according to an embodiment of the invention;
fig. 2 is a schematic structural diagram of an extended power flow device based on an optimization method according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The expanded power flow method and the device based on the optimization method according to the embodiment of the invention are described below with reference to the accompanying drawings, and first, the expanded power flow method based on the optimization method according to the embodiment of the invention will be described with reference to the accompanying drawings.
Fig. 1 is a flow chart of an extended trend method based on an optimization method according to an embodiment of the present invention.
As shown in fig. 1, the extended power flow method based on the optimization method includes the following steps:
in step S101, a relaxed bus voltage limit equation is established according to a limit formula.
Further, in one embodiment of the present invention, the bus voltage limit equation is established by a limit formula, the limit formula being:
wherein,the lower limit of the square of the bus voltage,upper limit of the square of the bus voltage, l and U being non-negative relaxation variables, UreAnd UimReal and imaginary parts, g, of complex variables of the bus voltage, respectivelyuIs the upper limit of the function, g is the mapping, glFor the lower limit of the function,is the square of the bus voltage.
In step S102, a power flow optimization problem with local voltage controllers is established by an optimization formula.
Further, in an embodiment of the present invention, the power flow optimization problem is established by the following optimization formula:
min∑(u+v)
wherein t is the position of the transformer tap, tminAnd tmaxThe method comprises the steps of respectively limiting the minimum value and the maximum value of a transformer tap position, h is mapping, v is a non-negative relaxation variable, and s.t. is a constraint condition.
In step S103, an optimization model of the zero injection bus, an optimization model of the PV bus, and an optimization model of the PQ bus are established by the constraint equations.
Further, in an embodiment of the present invention, the establishing an optimization model of a zero injection bus, an optimization model of a PV bus, and an optimization model of a PQ bus further includes:
for a zero injection bus, the first constraint equation h is expressed as a pair of linear equations:
wherein, IreAnd IimRespectively the real and imaginary part of the injected current, YzeroTo correspond to zero implantationU is the complex bus voltage,andthe real and imaginary parts of the equation, respectively.
For the PV bus, the second constraint equation h is expressed in pairs as:
wherein,is a voltage control target of the PV bus; subscript PV is the corresponding vector or matrix row of the PV bus, diag is the diagonal matrix, conjugate of the complex variable, SreIn order to inject the real part of the complex power,is the real part Y of the equationPVFor admittance rows corresponding to PV bus-bars, UPVIs the PV bus voltage, U is the complex bus voltage,is the real part of the PV bus voltage squared,the imaginary part of the PV bus voltage squared.
For the PQ bus, the third constraint equation h is expressed in pairs as:
wherein S isreAnd SimRespectively the real and imaginary parts of the injected complex power,andreal and imaginary parts of the equation, diag is the diagonal matrix, conjugate of complex variable, subscript PQ is the corresponding vector or matrix row of PQ bus, UPQIs PQ bus voltage, YPQU is the complex bus voltage for the admittance column corresponding to the PQ bus voltage.
In step S104, the optimization model of the zero injection bus, the optimization model of the PV bus, and the optimization model of the PQ bus are solved through IPM of the constant blackplug matrix to obtain integer tap positions, and a functional test is performed under three-phase balanced and unbalanced conditions.
Further, in one embodiment of the present invention, the integer tap positions are obtained by rounding the fractional values of the tap positions.
In a specific embodiment of the present invention, under a three-phase equilibrium condition, the power flow expansion method based on the optimization method proposed in the embodiment of the present invention includes the following steps:
s1: collecting data under light load or heavy load of distributed network power flow of a local voltage controller on the basis of a sensitivity method without considering nonlinearity.
S2: and establishing a relaxed bus voltage limit equation.
Wherein,the lower limit of the square of the bus voltage,is a masterUpper limit of the square of the line voltage, l and U being non-negative relaxation variables, UreAnd UimReal and imaginary parts, g, of complex variables of the bus voltage, respectivelyuIs the upper limit of the function, g is the mapping, glFor the lower limit of the function,is the square of the bus voltage.
S3: an optimization problem of power flow extension with local voltage controllers is established.
min∑(u+v)
Wherein, UreAnd UimRespectively the real part and the imaginary part of a complex variable of the bus voltage, t is the position of a transformer tap, tminAnd tmaxThe method comprises the steps of respectively limiting the minimum value and the maximum value of a transformer tap position, h is mapping, v is a non-negative relaxation variable, and s.t. is a constraint condition.
S4: and establishing a zero injection bus constraint equation.
Wherein, IreAnd IimRespectively the real and imaginary part of the injected current, YzeroFor the admittance row corresponding to the zero injection bus, U is the complex bus voltage,andthe real and imaginary parts of the equation, respectively.
S5: and establishing a PV bus constraint equation.
Wherein,for the voltage control target of the PV bus, the subscript PV is the corresponding vector or matrix row of the PV bus, diag is the diagonal matrix, the conjugate of the complex variable, SreIs the real part of the injected complex power;is the real part of the equation, YPVFor admittance rows corresponding to PV bus-bars, UPVIs the PV bus voltage, U is the complex bus voltage,is the real part of the PV bus voltage squared,the imaginary part of the PV bus voltage squared.
S6: and establishing a PQ bus constraint equation.
Wherein S isreAnd SimRespectively the real and imaginary parts of the injected complex power,andreal and imaginary parts of the equation, diag is the diagonal matrix, conjugate of complex variable, subscript PQ is the corresponding vector or matrix row of PQ bus, UPQIs PQ bus voltage, YPQU is the complex bus voltage for the admittance column corresponding to the PQ bus voltage.
S7: matlab is applied and the optimization problem described above is solved with IPM with constant blackplug matrix.
S8: the method provided by the embodiment of the invention is compared with the iteration times and time required by the sensitivity method and the expanded trend method, and the functionality of the method is verified.
In another specific embodiment of the present invention, under an unbalanced condition, the expanded power flow method based on the optimization method proposed by the embodiment of the present invention includes the following steps:
s1: and establishing a relaxed bus voltage limit equation.
Wherein,the lower limit of the square of the bus voltage,for the upper limit of the square of the bus voltage, l and U are non-negative relaxation variables UreAnd UimReal and imaginary parts, g, of complex variables of the bus voltage, respectivelyuIs the upper limit of the function, g is the mapping, glFor the lower limit of the function,is the square of the bus voltage.
S2: an optimization problem of power flow extension with local voltage controllers is established.
min∑(u+v)
Wherein, UreAnd UimAre respectively bus-bar electricityReal and imaginary parts of the complex-valued variable, t being the transformer tap position, tminAnd tmaxThe method comprises the steps of respectively limiting the minimum value and the maximum value of a transformer tap position, h is mapping, v is a non-negative relaxation variable, and s.t. is a constraint condition.
S3: and establishing a zero injection bus constraint equation.
Wherein, IreAnd IimRespectively the real and imaginary part of the injected current, YzeroFor the admittance row corresponding to the zero-injection bus, U represents the complex bus voltage,andthe real and imaginary parts of the equation, respectively.
S4: and establishing a PV bus constraint equation.
Wherein,for the voltage control target of the PV bus, the subscript PV is the corresponding vector or matrix row of the PV bus, diag is the diagonal matrix, the conjugate of the complex variable, SreIs the real part of the injected complex power;is the real part of the equation, YPVFor admittance rows corresponding to PV bus-bars, UPVIs the PV bus voltage, U is the complex bus voltage,is the real part of the PV bus voltage squared,the imaginary part of the PV bus voltage squared.
S5: and establishing a PQ bus constraint equation.
Wherein S isreAnd SimRespectively the real and imaginary parts of the injected complex power,andreal and imaginary parts of the equation, diag is the diagonal matrix, conjugate of complex variable, subscript PQ is the corresponding vector or matrix row of PQ bus, UPQIs PQ bus voltage, YPQU is the complex bus voltage for the admittance column corresponding to the PQ bus voltage.
S6: the optimization problem is solved using an IPM with a constant blackplug matrix using Matlab.
S7: according to [ I.Kocar, J.Mahseredjian, U.Karaagac, G.Soykan, and O.Saad, "Multiphase Load-Flow Solution for Large-Scale Distribution Systems Using ManA," IEEE Transactions on Power Delivery, vol.29, No.2, pp.908-915, Apr.2014 ], a step voltage regulator model is known to be represented by a voltage controlled voltage source and a current controlled current source.
S8: IEEE4 bus test feeder data was collected [ W.H.Kersting, Distribution System Modeling and Analysis, third edition. boca Raton, Florida: CRC Press,2012 ].
S9: comparing the load flow result adjusted by the step voltage regulator with the iteration times of the method provided by the embodiment of the invention, the method provided by the embodiment of the invention has the advantage of less iteration times.
S10: multiplying the C-phase load on the IEEE4 bus by 2 to obtain the infeasible voltage limit of the method of the embodiment of the invention verifies that the method of the embodiment of the invention has the functionality of detecting the infeasible voltage limit and the relaxation capacity.
According to the power flow expanding method based on the optimization method provided by the embodiment of the invention, the IPM of the constant blackplug matrix is used for solving the optimization model of the zero injection bus, the optimization model of the PV bus and the optimization model of the PQ bus, so that the integer tap position is obtained, the function test is carried out under the conditions of three-phase balance and unbalance, the purpose of power flow expanding based on the optimization method is realized, the nonlinear problem that the distributed network power flow of a local voltage controller is responded by a sensitive method under the heavy load condition and the problem that the limitation of the infeasible voltage is detected and relaxed under the heavy load condition are solved, the convergence of the nonlinear sensitivity method under the heavy load condition is improved, and the method is suitable for detecting and relaxing the limitation of the infeasible voltage under the heavy load condition.
Next, an extended power flow apparatus based on an optimization method according to an embodiment of the present invention will be described with reference to the drawings.
Fig. 2 is a schematic structural diagram of an extended power flow device based on an optimization method according to an embodiment of the present invention.
As shown in fig. 2, the extended power flow device 10 based on the optimization method includes: a constraint equation building module 100, an optimization problem building module 200, an optimization model building module 300 and a power flow extension module 400.
The constraint equation establishing module 100 is configured to establish a relaxed bus voltage constraint equation according to a constraint equation. The optimization problem establishing module 200 is used for establishing a power flow optimization problem with local voltage controllers through an optimization formula. The optimization model building module 300 is used for building an optimization model of the zero injection bus, an optimization model of the PV bus and an optimization model of the PQ bus through constraint equations. The power flow expansion module 400 is configured to solve the optimization model of the zero injection bus, the optimization model of the PV bus, and the optimization model of the PQ bus through IPM of the constant black plug matrix to obtain an integer tap position, and perform a functional test under three-phase balanced and unbalanced conditions. The device 10 of the embodiment of the invention can improve the convergence of the nonlinear sensitivity method under the heavy load condition, is suitable for detecting and relaxing the infeasible voltage limitation under the heavy load condition, and ensures the solvability of the tide.
Further, in one embodiment of the present invention, the restriction equation in the restriction equation establishing module 100 is:
wherein,the lower limit of the square of the bus voltage,for the upper limit of the square of the bus voltage, l and U represent non-negative relaxation variables, UreAnd UimReal and imaginary parts, g, of complex variables of the bus voltage, respectivelyuIs the upper limit of the function, g is the mapping, glFor the lower limit of the function,is the square of the bus voltage.
Further, in an embodiment of the present invention, the optimization formula in the optimization problem establishing module 200 is:
min∑(u+v)
wherein t is the position of the transformer tap, tminAnd tmaxRespectively the position of a transformer tapH is the mapping, v is the non-negative relaxation variable, and s.t. is the constraint.
Further, in an embodiment of the present invention, the optimization model building module 300 further includes:
for a zero injection bus, the first constraint equation h is expressed as a pair of linear equations:
wherein, IreAnd IimRespectively the real and imaginary part of the injected current, YzeroFor the admittance row corresponding to the zero injection bus, U is the complex bus voltage,andthe real and imaginary parts of the equation, respectively.
For the PV bus, the second constraint equation h is expressed in pairs as:
wherein,for the voltage control target of the PV bus, the subscript PV is the corresponding vector or matrix row of the PV bus, diag is the diagonal matrix, the conjugate of the complex variable, SreIn order to inject the real part of the complex power,is the real part of the equation, YPVFor admittance rows corresponding to PV bus-bars, UPVIs the PV bus voltage, U is the complex bus voltage,is the real part of the PV bus voltage squared,the imaginary part of the PV bus voltage squared.
For the PQ bus, the third constraint equation h is expressed in pairs as:
wherein S isreAnd SimRespectively the real and imaginary parts of the injected complex power,andreal and imaginary parts of the equation, diag is the diagonal matrix, conjugate of complex variable, subscript PQ is the corresponding vector or matrix row of PQ bus, UPQIs PQ bus voltage, YPQU is the complex bus voltage for the admittance column corresponding to the PQ bus voltage.
Further not in one embodiment of the present invention, the integer tap positions are obtained by rounding the fractional values of the tap positions.
It should be noted that the foregoing explanation of the embodiment of the expanded power flow method based on the optimization method is also applicable to the expanded power flow device based on the optimization method of the embodiment, and details are not repeated here.
According to the expanded power flow device based on the optimization method, the optimization model of the zero injection bus, the optimization model of the PV bus and the optimization model of the PQ bus are solved through the IPM of the constant blackplug matrix, so that the integer tap position is obtained, the function test is carried out under the conditions of three-phase balance and unbalance, the purpose of expanding the power flow based on the optimization method is achieved, the nonlinear problem that the distributed network power flow of a local voltage controller is responded by a sensitive method under the heavy load condition and the problem that the limitation of the infeasible voltage is detected and relaxed under the heavy load condition are solved, the convergence of the nonlinear sensitivity method under the heavy load condition is improved, and the expanded power flow device is suitable for detecting and relaxing the limitation of the infeasible voltage under the heavy load condition.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. An expanded trend method based on an optimization method is characterized by comprising the following steps:
establishing a relaxed bus voltage limit equation according to a limit formula;
establishing a power flow optimization problem with a local voltage controller through an optimization formula;
establishing an optimization model of a zero injection bus, an optimization model of a PV bus and an optimization model of a PQ bus through a constraint equation; and
and solving the optimization model of the zero injection bus, the optimization model of the PV bus and the optimization model of the PQ bus through the IPM of the constant black plug matrix to obtain an integer tap position, and performing functional test under the conditions of three-phase balance and unbalance.
2. The optimization method based expanded power flow method of claim 1, wherein the bus voltage limiting equation is established by a limiting formula, the limiting formula being:
wherein,the lower limit of the square of the bus voltage,is the upper limit of the square of the bus voltage, l and U are non-negative relaxation variables, UreAnd UimReal and imaginary parts, g, of complex variables of the bus voltage, respectivelyuIs the upper limit of the function, g is the mapping, glIs the lower limit of the function and,is the bus voltage squared.
3. The optimization method based expanded power flow method of claim 2, wherein the power flow optimization problem is established by the following optimization formula:
wherein t is the position of the transformer tap, tminAnd tmaxThe minimum value limit and the maximum value limit of the transformer tap position are respectively, h is mapping, v is non-negative relaxation changeThe quantity, s.t. is a constraint.
4. The optimization method based expanded power flow method of claim 1, wherein the establishing of the optimization model of the zero injection bus, the optimization model of the PV bus and the optimization model of the PQ bus further comprises:
for the zero injection bus, the first constraint equation h is expressed as a pair of linear equations:
wherein, IreAnd IimRespectively the real and imaginary part of the injected current, YzeroFor the admittance row corresponding to the zero injection bus, U is the complex bus voltage,andthe real and imaginary parts of the equation, respectively.
For the PV bus, a second constraint equation h is expressed in pairs as:
wherein,for the voltage control target of the PV bus, the subscript PV is the corresponding vector or matrix row of the PV bus, diag is the diagonal matrix, the conjugate of the complex variable, SreIn order to inject the real part of the complex power,is the real part of the equation, YPVFor admittance rows corresponding to PV bus-bars, UPVIs the PV bus voltage, U is the complex bus voltage,is the real part of the PV bus voltage,the imaginary part of the PV bus voltage.
For the PQ bus, the third constraint equation h is expressed in pairs as:
wherein S isreAnd SimRespectively the real and imaginary parts of the injected complex power,andreal and imaginary parts of the equation, diag is the diagonal matrix, conjugate of complex variable, subscript PQ is the corresponding vector or matrix row of PQ bus, UPQIs PQ bus voltage, YPQU is the complex bus voltage for the admittance row corresponding to the PQ bus.
5. The optimization-method-based extended power flow method of claim 1, wherein the integer tap positions are obtained by rounding off the fractional values of the tap positions.
6. An expanded power flow device based on an optimization method is characterized by comprising the following steps:
the limiting equation establishing module is used for establishing a relaxed bus voltage limiting equation according to a limiting formula;
the optimization problem establishing module is used for establishing a power flow optimization problem with a local voltage controller through an optimization formula;
the optimization model establishing module is used for establishing an optimization model of the zero injection bus, an optimization model of the PV bus and an optimization model of the PQ bus through a constraint equation; and
and the power flow expansion module is used for solving the optimization model of the zero injection bus, the optimization model of the PV bus and the optimization model of the PQ bus through IPM of the constant black plug matrix to obtain an integer tap position, and performing functional test under three-phase balance and unbalance conditions.
7. The optimization-method-based expanded power flow device of claim 6, wherein: the restriction formula in the restriction equation establishing module is as follows:
wherein,the lower limit of the square of the bus voltage,for the upper limit of the square of the bus voltage, l and U represent non-negative relaxation variables, UreAnd UimReal and imaginary parts, g, of complex variables of the bus voltage, respectivelyuIs the upper limit of the function, g is the mapping, glFor the lower limit of the function,is the bus voltage squared.
8. The extended power flow device based on the optimization method of claim 7, wherein the optimization formula in the optimization problem establishing module is as follows:
wherein t is the tap position of the transformerT is putminAnd tmaxThe minimum value limit and the maximum value limit of the transformer tap position are respectively, h is mapping, v is a non-negative relaxation variable, and s.t. is a constraint condition.
9. The extended power flow device based on optimization method of claim 6, wherein the optimization model building module further comprises:
for the zero injection bus, the first constraint equation h is expressed as a pair of linear equations:
wherein, IreAnd IimRespectively the real and imaginary part of the injected current, YzeroFor the admittance row corresponding to the zero injection bus, U is the complex bus voltage,andthe real and imaginary parts of the equation, respectively.
For the PV bus, a second constraint equation h is expressed in pairs as:
wherein,for the voltage control target of the PV bus, the subscript PV is the corresponding vector or matrix row of the PV bus, diag is the diagonal matrix, the conjugate of the complex variable, SreIn order to inject the real part of the complex power,is the real part of the equation, YPVTo correspond to the PV motherAdmittance of the wire, UPVIs the PV bus voltage, U is the complex bus voltage,is the real part of the PV bus voltage,the imaginary part of the PV bus voltage.
For the PQ bus, the third constraint equation h is expressed in pairs as:
wherein S isreAnd SimRespectively the real and imaginary parts of the injected complex power,andreal and imaginary parts of the equation, diag is the diagonal matrix, conjugate of complex variable, subscript PQ is the corresponding vector or matrix row of PQ bus, UPQIs PQ bus voltage, YPQU is the complex bus voltage for the admittance row corresponding to the PQ bus.
10. The optimization-based extended power flow device of claim 6, wherein the integer tap positions are obtained by rounding off the fractional values of the tap positions.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2482417A2 (en) * | 2011-01-27 | 2012-08-01 | General Electric Company | Systems, Methods, and Apparatus for Accelerating Volt/VAR Load Flow Optimization |
| CN103150606A (en) * | 2013-01-22 | 2013-06-12 | 中国电力科学研究院 | Optimal power flow optimization method of distributed power supplies |
| CN103151784A (en) * | 2013-04-01 | 2013-06-12 | 国家电网公司 | AVC (automatic voltage control) system-based reactive voltage optimization method and device |
| CN104092213A (en) * | 2014-07-30 | 2014-10-08 | 东南大学 | Power analyzing method for indeterminate power flow branches based on optimization method |
| CN106253288A (en) * | 2016-07-19 | 2016-12-21 | 河海大学 | A kind of optimal load flow algorithm containing THE UPFC based on automatic differential |
| CN106532710A (en) * | 2016-11-04 | 2017-03-22 | 国网山东省电力公司 | Microgrid power flow optimization method considering voltage stability constraint |
-
2017
- 2017-11-02 CN CN201711064949.8A patent/CN109755942B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2482417A2 (en) * | 2011-01-27 | 2012-08-01 | General Electric Company | Systems, Methods, and Apparatus for Accelerating Volt/VAR Load Flow Optimization |
| CN103150606A (en) * | 2013-01-22 | 2013-06-12 | 中国电力科学研究院 | Optimal power flow optimization method of distributed power supplies |
| CN103151784A (en) * | 2013-04-01 | 2013-06-12 | 国家电网公司 | AVC (automatic voltage control) system-based reactive voltage optimization method and device |
| CN104092213A (en) * | 2014-07-30 | 2014-10-08 | 东南大学 | Power analyzing method for indeterminate power flow branches based on optimization method |
| CN106253288A (en) * | 2016-07-19 | 2016-12-21 | 河海大学 | A kind of optimal load flow algorithm containing THE UPFC based on automatic differential |
| CN106532710A (en) * | 2016-11-04 | 2017-03-22 | 国网山东省电力公司 | Microgrid power flow optimization method considering voltage stability constraint |
Non-Patent Citations (1)
| Title |
|---|
| 雷婧婷 等: "含直流配电网的交直流潮流计算", 《中国电机工程学报》 * |
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