CN110957728A - All-pure embedded tide method and device for three-phase active power distribution network - Google Patents
All-pure embedded tide method and device for three-phase active power distribution network Download PDFInfo
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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Abstract
The embodiment of the invention provides a full-pure embedded power flow method and a device of a three-phase active power distribution network, wherein the method comprises the following steps: establishing a three-phase active power distribution network model, wherein the three-phase active power distribution network model comprises a three-phase bus and a calculation node; under the network constraint condition, carrying out load flow calculation on the three-phase bus and the calculation node to obtain power; if the power convergence is judged and obtained according to the convergence criterion value, judging whether the stepping voltage regulator exceeds the voltage limit; and if the step voltage regulator is judged and known not to exceed the voltage limit, obtaining a load flow calculation result. The all-pure embedded power flow method and the all-pure embedded power flow device for the three-phase active power distribution network, provided by the embodiment of the invention, can be used for simultaneously calculating power flow under loads of different scales so as to improve voltage stability and balance a transmission network.
Description
Technical Field
The invention relates to the field of electric power, in particular to a full-pure embedded tide method and device for a three-phase active power distribution network.
Background
The tidal current calculation is an important analysis calculation of the power system to study various problems in system planning and operation. The load flow calculation is to calculate the voltage of each bus, the current and the power of each branch and the network loss when the power system operates in a steady state by knowing the wiring mode, parameters and operating conditions of the power grid. For the running power system, whether the voltage of a power grid bus, the branch current and the power are out of limit or not can be judged through load flow calculation, and if the voltage, the branch current and the power are out of limit, measures are taken to adjust the running mode.
For the power system being planned, a basis can be provided for selecting a power supply scheme of a power grid and electrical equipment through load flow calculation. The load flow calculation can also provide raw data for relay protection and automatic device setting calculation, power system fault calculation, stability calculation and the like.
The existing power flow calculation methods mainly include an improved Newton method, an optimal multiplier method, a nonlinear programming method, a homotopy method and the like, but the methods often have the problem of convergence failure when facing power flow calculation caused by high-power transmission, and a transmission network cannot be balanced, so that a method capable of overcoming the convergence failure when facing power flow calculation caused by high-power transmission is urgently needed.
Disclosure of Invention
In order to overcome the technical defects, the embodiment of the invention provides a full-pure embedded tide method and device for a three-phase active power distribution network.
In a first aspect, an embodiment of the present invention provides a full-pure embedded power flow method for a three-phase active power distribution network, including:
establishing a three-phase active power distribution network model, wherein the three-phase active power distribution network model comprises a three-phase bus and a calculation node;
under the network constraint condition, carrying out load flow calculation on the three-phase bus and the calculation node to obtain power;
if the power convergence is judged and obtained according to the convergence criterion value, judging whether the stepping voltage regulator exceeds the voltage limit;
and if the step voltage regulator is judged and known not to exceed the voltage limit, obtaining a load flow calculation result.
In a second aspect, an embodiment of the present invention provides an all-pure embedded power flow device for a three-phase active power distribution network, including:
the model establishing module is used for establishing a three-phase active power distribution network model, and the three-phase active power distribution network model comprises a three-phase bus and a computing node;
the load flow calculation module is used for carrying out load flow calculation on the three-phase bus and the calculation node under the network constraint condition to obtain power;
the first processing module is used for judging whether the stepping voltage regulator exceeds the voltage limit or not if the power convergence is judged and obtained according to the convergence criterion value;
and the second processing module is used for acquiring a load flow calculation result if the step voltage regulator is judged and known not to exceed the voltage limit.
In a third aspect, an embodiment of the present invention provides an electronic device, including a memory and a processor, where the processor and the memory complete communication with each other through a bus; the memory stores program instructions executable by the processor, the processor being capable of performing the method of the first aspect when invoked by the processor.
In a fourth aspect, an embodiment of the present invention provides a non-transitory computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements a fully-embedded power flow method for a three-phase active power distribution network according to the first aspect.
The all-pure embedded power flow method and the all-pure embedded power flow device for the three-phase active power distribution network are applied to voltage stability analysis and simplification of a nonlinear network, can calculate power flow under loads of different scales at the same time, and overcome the problem of convergence failure in high-power flow calculation, so that voltage stability is improved, and a transmission network is balanced.
Drawings
Fig. 1 is a schematic flow chart of a pure embedded power flow method of a three-phase active power distribution network according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an all-pure embedded power flow device of a three-phase active power distribution network according to an embodiment of the present invention;
fig. 3 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
And load flow calculation, namely calculating the distribution of active power, reactive power and voltage in the power grid under the conditions of given power system network topology, element parameters, power generation parameters and load parameters. The tidal current calculation is a calculation for determining steady-state operation state parameters of each part of the power system according to the given power grid structure, parameters and operation conditions of elements such as a generator and a load. Typically given operating conditions there are power at each source and load point in the system, pivot point voltage, voltage at the balance point and phase angle. The operating state parameters to be solved comprise voltage amplitude and phase angle of each bus node of the power grid, power distribution of each branch circuit, power loss of the network and the like.
Fig. 1 is a schematic flow chart of a pure embedded power flow method of a three-phase active power distribution network according to an embodiment of the present invention, as shown in fig. 1, including:
step 12, carrying out load flow calculation on the three-phase bus and the calculation node under the network constraint condition to obtain power;
and 14, if the step voltage regulator is judged and obtained not to exceed the voltage limit, obtaining a load flow calculation result.
The tidal current calculation is an important analysis calculation of the power system to study various problems in system planning and operation. For the power system in the planning, whether the proposed power system planning scheme can meet the requirements of various operation modes can be checked through load flow calculation; for an operating electric power system, various load changes and changes of a network structure can be predicted through load flow calculation, the safety of the system can not be endangered, whether the voltage of all buses in the system is within an allowable range or not, whether overload occurs to various elements (lines, transformers and the like) in the system or not, which preventive measures should be taken in advance when overload possibly occurs and the like, and meanwhile, the load flow calculation is also the basis of network loss calculation, static safety analysis, transient stability calculation, small-interference static stability calculation, short circuit calculation and static and dynamic equivalence calculation.
The load flow calculation can be mathematically reduced to solve a nonlinear equation system, and the mathematical model is abbreviated as follows:
f (X) ═ 0 is a nonlinear equation system
Wherein:
f ═ T (F1, F2........, fn) is the node balance equation;
x ═ T (X1, X2........ times.xn) is the voltage of each node to be solved.
This determined the following:
① iterative algorithm and convergence thereof
For the problem of the nonlinear equation system, various solving methods of the problem can not be iterated, so that the problem of whether iteration is converged exists.
② multivalue and existence of solution
For solving a system of nonlinear equations, there should be multiple sets of solutions from a mathematical point of view. Generally, a reasonable solution can be converged to according to an initial value set in the program. But there are special cases where convergence to an incomprehensible (too low or too high voltage) is also possible. These solutions are mathematical solutions (because they satisfy the node balancing equations) and not actual solutions. For this purpose, the operating conditions are changed and the calculation is carried out again. In addition, the components (magnitude and angle or real and imaginary parts) of the node voltage required for the power flow calculation problem. It is only meaningful if it is real. If there is no real solution in a given operating condition, the problem is considered to be solution-free.
Thus, when the iterations do not converge, two cases are possible: firstly, the solution (meaning real number solution) does not exist, and the operation mode needs to be modified at the moment; the other is that the calculation method does not converge, and at this time, the calculation method needs to be replaced.
The current widely applied load flow calculation method is based on a node voltage method, and a node admittance matrix Y is used as a mathematical model of the power network. Node voltage UiAnd node injection current IiLinked by a node voltage equation. In a practical power system, the known operating conditions are not the injected current of the node, but the power of the load and the generator, and these powers do not generally vary with the voltage of the node.
Knowing the wiring and each branch parameter of the network, a node admittance matrix Y in the load flow calculation can be formed. The variable for representing the running state of the system in the power flow equation is the injected active power PiReactive power QiAnd node voltage phasor Ui。
The three-phase fully-pure embedded power flow method is characterized in that a pure power balance equation is used, and complex node voltages are converted into a node voltage power series function through an analytic continuation technology.
The embodiment of the invention is realized by adopting the following scheme:
firstly, a three-phase all-pure embedded power flow method is introduced, and the complex node voltage can be expressed as a power series form of a complex number s:
where V [ n ] is the Taylor series coefficient and n is the exponent.
The taylor series of the power balance equation is:
where V [ n ] is the Taylor series coefficient and n is the exponent.
The coefficients of the left side and the right side must be equal to obtain a new power balance equation:
wherein f (V0, V1, …) and g (V0, V1, …) are linear functions of V0, V1, … Vn.
The linear constraint of the three-phase all-pure embedded power flow method on the voltage of a complex node is assumed as follows:
A·V＝b (4)
according to (1), the above equation can be expressed as a power series:
converting the linear constraint of (5) into:
under the constraint condition of the unique linear network, calculating complex voltage, complex phase voltage, complex injection current and complex phase current so as to obtain power.
Judging power mismatch through a convergence criterion; if the convergence criterion is met, a check is made as to whether the Step Voltage Regulator (SVR) exceeds the voltage limit. If oscillation occurs, matching fails and the process stops. Otherwise, whether the power is mismatched is judged again.
It is checked whether the Step Voltage Regulator (SVR) exceeds the voltage limit. And if the voltage limit is not exceeded, obtaining the result of the load flow calculation, namely the voltage and the current of each node of the nonlinear equation set to be solved.
The all-pure embedded power flow method of the three-phase active power distribution network provided by the embodiment of the invention is applied to voltage stability analysis and simplification of a nonlinear network, can simultaneously calculate power flow under loads of different scales, and overcomes the problem of convergence failure in high-power flow calculation, so that the voltage stability is improved, and the transmission network is balanced.
On the basis of the embodiment, the three-phase active power distribution network model comprises a triangular connection load model, a distributed power supply load model and a ZIP load model.
The current widely applied load flow calculation method is based on a node voltage method, and a node admittance matrix Y is used as a mathematical model of the power network. Node voltage UiAnd node injection current IiLinked by a node voltage equation. In a practical power system, the known operating conditions are not the injected current of the node, but the power of the load and the generator, and these powers do not generally vary with the voltage of the node.
Knowing the wiring and each branch parameter of the network, a node admittance matrix Y in the load flow calculation can be formed. The variable for representing the running state of the system in the power flow equation is the injected active power PiReactive power QiAnd node voltage phasor Ui(amplitude U)iAnd phase angle deltai). The power grid of n nodes has 4n variables, but only 2n power equations, and therefore 2n of them must be given operating state variables. Depending on the variables of a given node, there may be three types of nodes as follows.
PU node (voltage control bus) active power PiSum voltage amplitude UiIs given. This type of node corresponds to a generator bus node or to a substation bus equipped with a phase modulator or a static compensator.
PQ node, injecting active power PiAnd reactive power QiIs given. Corresponding to a load node in the actual power system, or a generator bus for a given active and reactive power.
And the balance node is used for balancing the power of the whole power grid. Voltage amplitude U of the balanced nodeiAnd phase angle deltaiIs given, usually with its phase angle as a reference point, i.e.The voltage phase angle is taken to be zero. Only one balancing node is arranged in an independent power grid.
The establishment of the three-phase active power distribution network model specifically comprises the following steps:
acquiring complex node voltage of the computing node, and representing the complex node voltage in a power series form;
acquiring a power balance equation, and acquiring a new power balance equation according to a power series form of the complex node voltage and the power balance equation;
and obtaining the network constraint condition according to the new power balance equation.
And establishing a three-phase active power distribution network model. First, three-phase busbars (TBus) and computing nodes (CNodes) are defined, each of which has a single-phase node, a two-phase node or a three-phase node in the analysis of a three-phase network. For clarity of description herein, TBus is used to denote the set of nodes and CNodes. CNodes are used for three-phase load flow numerical calculation.
The representing the complex node voltage in a power series form specifically includes:
the complex node voltage V is represented as a power series form of a complex number s,
where V(s) is the power series form of the complex node voltage, V [ n ] is the Taylor series coefficient, and n is the exponent.
Obtaining a new power balance equation according to the power series form of the complex node voltage and the power balance equation, specifically comprising:
the power balance equation is expressed in the form of a taylor series,
wherein V (n) is Taylor series coefficient, n is index, F is emitting power, G is consuming power;
according to the equality of the coefficients of the two sides of the equation, a new power balance equation is obtained,
f(V[0],V[1],...)＝f[0]＝g[0]＝g(V[0],V[1],...),
…,
f[n]＝g[n-1],
wherein f (V0, V1, …) and g (V0, V1, …) are linear functions of V0, V1, … Vn.
And the triangular load connection model comprises Y-type connection and D-type connection.
Y-connected PQ loading model TBus. There are three CNodes for PQ loads for Y-connections. Each PQ CNodes was easily handled by a three-phase HELM. The formula is as follows:
in which i and ncDenotes the index of CNode, PiAnd QiIt is meant that the node is injecting power,
is the admittance matrix of the CNode. Wi *[s]Is defined as:
Wi *[s]＝1/Vi *[s*]＝Wi *[0]+Wi *[1]s+Wi *[2]s2+…(8)
obtain an initial solution Vi[0]Through Wi *[s]And Vi *[s]The coefficients in (8) can be calculated by convolution:
model D connected PQ loading model TBu. Let i, j, k be three-phase CNodes for PQ loads connected in D-mode. We add an interphase complex voltage as an additional variable, the linear constraint is as follows:
this linear constraint is easily accommodated by the HELM.
At CNode i, the fully pure embedding formula is as follows:
in the formula (I), the compound is shown in the specification,
at CNode j, the fully pure embedding formula is as follows:
a distributed power model. The photovoltaic power generation of the power electronics interface is mainly considered here.
Through impedance ZdgThe latter current or voltage source may model the power electronic interface generator. There are two control modes for a three-phase converter:
balancing internal voltage Vi＝Vjej120°＝Vke-j120°，
Balancing the injection current Ii＝Ijej120°＝Ike-j120°。
(1) Internal voltages are balanced under no voltage control. The voltage constraints are:
i denotes a certain stage.
The pure embedding formula is as follows:
(2) the internal voltage is balanced under voltage control. In addition to two linear voltage constraints, for amplitude voltage | ViControl of l, additionAn all-pure embedded formula:
where the subscript re denotes the real part of the complex number,
is the object of voltage amplitude control, deltaniKronecker sign function:
the total reactive power of the DGs is unknown. The pure embedding formula is as follows:
the product of two power series can be described by convolution; also, the coefficients of the above equation can be converted to the following equation:
in the formula
Representing the convolution of two power series.
(3) The balance injection current, namely the current flowing into a certain node is equal to the current flowing out, and the power series is as follows:
the linearity constraint of the injected current is as follows:
the total injected power constraint is:
in the formula:
ZIP load
In the all-pure embedded formula, the current of the ZIP load is crucial. The constant impedance and constant power portions of the ZIP load are separately represented. Such as a linear impedance branch and PQ loading with respect to CNode voltage.
For the current component of the wye connection, the load is:
Si＝ap,IP0|Vi|+jaq,IQ0|Vi| (23)
wherein, ap,I，P0，Q0Is the coefficient of the ZIP load, constant. By derivation, the power series of coefficients of the injected current is:
also, regarding the phase-to-phase branch current IijDerivation of the D-type connection current component may also be implemented.
The all-pure embedded power flow method of the three-phase active power distribution network provided by the embodiment of the invention is applied to voltage stability analysis and simplification of a nonlinear network, can simultaneously calculate power flow under loads of different scales, and overcomes the problem of convergence failure in high-power flow calculation, so that the voltage stability is improved, and the transmission network is balanced.
On the basis of the above embodiment, if it is determined that the power is not converged according to the convergence criterion value, the operation is stopped.
The network constraint conditions are as follows:
YV[0]＝0，
where Y is the admittance matrix and V0 is the complex node voltage.
Y-connected PQ loading model TBus. There are three CNodes for PQ loads for Y-connections. Each PQ CNodes was easily handled by a three-phase HELM. The formula is as follows:
in which i and ncDenotes the index of CNode, PiAnd QiIt is meant that the node is injecting power,
is the admittance matrix of the CNode. Wi *[s]Is defined as:
Wi *[s]＝1/Vi *[s*]＝Wi *[0]+Wi *[1]s+Wi *[2]s2+…(8)
obtain an initial solution Vi[0]Through Wi *[s]And Vi *[s]The coefficients in (8) can be calculated by convolution:
model D connected PQ loading model TBu. Let i, j, k be three-phase CNodes for PQ loads connected in D-mode. We add an interphase complex voltage as an additional variable, the linear constraint is as follows:
this linear constraint is easily accommodated by the HELM.
At CNode i, the fully pure embedding formula is as follows:
in the formula (I), the compound is shown in the specification,
at CNode j, the fully pure embedding formula is as follows:
a distributed power model. The photovoltaic power generation of the power electronics interface is mainly considered here.
Through impedance ZdgThe latter current or voltage source may model the power electronic interface generator. There are two control modes for a three-phase converter:
balancing internal voltage Vi＝Vjej120°＝Vke-j120°，
Balancing the injection current Ii＝Ijej120°＝Ike-j120°。
(1) Internal voltages are balanced under no voltage control. The voltage constraints are:
i denotes a certain stage.
The pure embedding formula is as follows:
(2) the internal voltage is balanced under voltage control. In addition to two linear voltage constraints, for amplitude voltage | ViAnd | control, adding an all-pure embedded formula:
where the subscript re denotes the real part of the complex number,
is the object of voltage amplitude control, deltaniKronecker sign function:
the total reactive power of the DGs is unknown. The pure embedding formula is as follows:
the product of two power series can be described by convolution; also, the coefficients of the above equation can be converted to the following equation:
in the formula
Representing the convolution of two power series.
(3) The balance injection current, namely the current flowing into a certain node is equal to the current flowing out, and the power series is as follows:
the linearity constraint of the injected current is as follows:
the total injected power constraint is:
in the formula:
ZIP load
In the all-pure embedded formula, the current of the ZIP load is crucial. The constant impedance and constant power portions of the ZIP load are separately represented. Such as a linear impedance branch and PQ loading with respect to CNode voltage.
For the current component of the wye connection, the load is:
Si＝ap,IP0|Vi|+jaq,IQ0|Vi| (23)
wherein, ap,I，P0，Q0Is the coefficient of the ZIP load, constant. By derivation, the power series of coefficients of the injected current is:
also, regarding the phase-to-phase branch current IijDerivation of the D-type connection current component may also be implemented.
Zero injection CNode
The zero injection constraint is:
a voltage regulator is stepped. The step voltage regulator is widely applied to an Active Distribution Network (ADN), and the line voltage drop compensator passes through a voltage transformer (transformation ratio N)PT1) and current transformer (transformation ratio CT)p:CTs) Coupled to the distribution line. The impedance of the compensator is expressed as an equivalent impedance from the regulator to the center of the load. The voltage of the relay is
Vrelay＝Vreg-Vdrop＝Vreg-(Rij,cΩ+jXij,cΩ)Iij(26)
In the formula Rij,cΩ+jXij,cΩRepresenting the impedance, V, of the compensatorregIs the secondary side voltage of the voltage transformer, VdropIs a line current IijA voltage drop across the equivalent impedance of the compensator.
A floating point network. The floating point network is directed to the delta connection load model, and the floating point network has a problem because the delta connected active distribution network has no reference CNode. This problem is solved by adding a zero sequence reference constraint to the three-phase abc CNode (i, j, k).
Vi+Vj+Vk＝0 (27)
Through (10) (13) (20), constraint YV [0] of unique linear network]Under 0, the complex voltage V is calculatedi[0]Multiple phase voltage Vij[0]The composite injection current Ii[0](for DGs) and complex interphase current Iij[0](for delta connection ZIP loads).
For the m-th term, V is calculated from the above-mentioned power series expressions (7) (11) (14) (15) (17) (21) (24)i[m]，Vij[m]，Ii[m]，Iij[m]I.e. each term of the expansion of the taylor series corresponding to the quantity.
Judging power mismatch through a convergence criterion; if the convergence criterion is satisfied, step S4 is performed. If oscillation occurs, matching fails and the process stops. Otherwise, returning to recalculate Vi[m]，Vij[m]，Ii[m]，Iij[m]I.e. each term of the expansion of the taylor series corresponding to the quantity.
It is checked whether the Step Voltage Regulator (SVR) exceeds the voltage limit. If the voltage limit is exceeded, the SVR tap is modified and the modified admittance matrix is returned.
And calculating all variables by x ═ x [0] + x [1] + x [2] + …, namely solving a corresponding nonlinear equation to obtain a power flow calculation result, wherein x is voltage and current.
Fig. 2 is a schematic structural diagram of an all-pure embedded power flow device of a three-phase active power distribution network according to an embodiment of the present invention, as shown in fig. 2, including a model building module 21, a power flow calculation module 22, a first processing module 23, and a second processing module 24, where:
the model establishing module 21 is configured to establish a three-phase active power distribution network model, where the three-phase active power distribution network model includes a three-phase bus and a computing node;
the load flow calculation module 22 is used for carrying out load flow calculation on the three-phase bus and the calculation node under the network constraint condition to obtain power;
the first processing module 23 is configured to determine whether the step voltage regulator exceeds the voltage limit if the power convergence is determined according to the convergence criterion value;
and the second processing module 24 is configured to obtain a load flow calculation result if it is determined that the step voltage regulator does not exceed the voltage limit.
And taking the node admittance matrix Y as a mathematical model of the power network, and connecting the node voltage Ui and the node injection current Ii by a node voltage equation. In a practical power system, the known operating conditions are not the injected current of the node, but the power of the load and the generator, and these powers do not generally vary with the voltage of the node.
Knowing the wiring and each branch parameter of the network, a node admittance matrix Y in the load flow calculation can be formed. The variable for representing the running state of the system in the power flow equation is the injected active power PiReactive power QiAnd node voltage phasor Ui(amplitude Ui and phase angle δi)。
The three-phase fully-pure embedded power flow method is characterized in that a pure power balance equation is used, and complex node voltages are converted into a node voltage power series function through an analytic continuation technology.
Firstly, a three-phase all-pure embedded power flow method is introduced, a model building module 21 builds a three-phase active power distribution network model, and it is assumed that complex node voltage can be expressed in a power series form of a complex number s:
where V [ n ] is the Taylor series coefficient and n is the exponent.
The taylor series of the power balance equation is:
where V [ n ] is the Taylor series coefficient and n is the exponent.
The coefficients of the left side and the right side must be equal to obtain a new power balance equation:
wherein f (V0, V1, …) and g (V0, V1, …) are linear functions of V0, V1, … Vn.
The linear constraint of the three-phase all-pure embedded power flow method on the voltage of a complex node is assumed as follows:
A·V＝b (4)
according to (1), the above equation can be expressed as a power series:
converting the linear constraint of (5) into:
the power flow calculation module 22 calculates complex voltage, complex phase-to-phase voltage, complex injection current and complex phase-to-phase current under the constraint condition of the unique linear network, thereby obtaining power.
The first processing module 23 judges power mismatch by a convergence criterion; if the convergence criterion is met, a check is made as to whether the Step Voltage Regulator (SVR) exceeds the voltage limit. If oscillation occurs, matching fails and the process stops. Otherwise, whether the power is mismatched is judged again.
The second processing module 24 checks whether the Step Voltage Regulator (SVR) exceeds the voltage limit. And if the voltage limit is not exceeded, obtaining the result of the load flow calculation, namely the voltage and the current of each node of the nonlinear equation set to be solved.
The apparatus provided in the embodiment of the present invention is used for executing the above method embodiments, and for detailed descriptions and specific processes, reference is made to the above method embodiments, which are not described herein again.
The all-pure embedded power flow device of the three-phase active power distribution network provided by the embodiment of the invention is applied to voltage stability analysis and simplification of a nonlinear network, can simultaneously calculate power flow under loads of different scales, and overcomes the problem of convergence failure in high-power flow calculation, so that the voltage stability is improved, and the transmission network is balanced.
Fig. 3 illustrates a physical structure diagram of an electronic device, which may include, as shown in fig. 3: a processor (processor)310, a communication Interface (communication Interface)320, a memory (memory)330 and a bus 340, wherein the processor 310, the communication Interface 320 and the memory 330 complete communication with each other through the bus 340. Bus 340 may be used for information transfer between the electronic device and the sensor. The processor 310 may call logic instructions in the memory 330 to perform the following method: establishing a three-phase active power distribution network model, wherein the three-phase active power distribution network model comprises a three-phase bus and a calculation node; under the network constraint condition, carrying out load flow calculation on the three-phase bus and the calculation node to obtain power; if the power convergence is judged and obtained according to the convergence criterion value, judging whether the stepping voltage regulator exceeds the voltage limit; and if the step voltage regulator is judged and known not to exceed the voltage limit, obtaining a load flow calculation result.
In addition, the logic instructions in the memory 330 may be implemented in the form of software functional units and stored in a computer readable storage medium when the software functional units are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
An embodiment of the present invention provides a non-transitory computer-readable storage medium, which stores computer instructions, where the computer instructions cause a computer to execute the method for fully-embedded power flow of a three-phase active power distribution network provided in the foregoing embodiment, for example, the method includes: establishing a three-phase active power distribution network model, wherein the three-phase active power distribution network model comprises a three-phase bus and a calculation node; under the network constraint condition, carrying out load flow calculation on the three-phase bus and the calculation node to obtain power; if the power convergence is judged and obtained according to the convergence criterion value, judging whether the stepping voltage regulator exceeds the voltage limit; and if the step voltage regulator is judged and known not to exceed the voltage limit, obtaining a load flow calculation result.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and additions may be made to the described embodiments by those skilled in the art without departing from the spirit of the invention or exceeding the scope as defined in the appended claims.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A full-pure embedded power flow method of a three-phase active power distribution network is characterized by comprising the following steps:
establishing a three-phase active power distribution network model, wherein the three-phase active power distribution network model comprises a three-phase bus and a calculation node;
under the network constraint condition, carrying out load flow calculation on the three-phase bus and the calculation node to obtain power;
if the power convergence is judged and obtained according to the convergence criterion value, judging whether the stepping voltage regulator exceeds the voltage limit;
and if the step voltage regulator is judged and known not to exceed the voltage limit, obtaining a load flow calculation result.
2. The method of claim 1, wherein the three-phase active power distribution network model comprises a delta connection load model, a distributed power load model, and a ZIP load model.
3. The method according to claim 2, wherein the establishing of the three-phase active power distribution network model specifically comprises:
acquiring complex node voltage of the computing node, and representing the complex node voltage in a power series form;
acquiring a power balance equation, and acquiring a new power balance equation according to a power series form of the complex node voltage and the power balance equation;
and obtaining the network constraint condition according to the new power balance equation.
4. The method of claim 3, wherein the representing the complex node voltage in a power series form comprises:
the complex node voltage V is represented as a power series form of a complex number s,
where V(s) is the power series form of the complex node voltage, V [ n ] is the Taylor series coefficient, and n is the exponent.
5. The method of claim 3, wherein obtaining a new power balance equation from the power series form of the complex node voltage and the power balance equation comprises:
the power balance equation is expressed in the form of a taylor series,
wherein V (n) is Taylor series coefficient, n is index, F is emitting power, G is consuming power;
according to the equality of the coefficients of the two sides of the equation, a new power balance equation is obtained,
f(V[0],V[1],...)＝f[0]＝g[0]＝g(V[0],V[1],...),
…,
f[n]＝g[n-1],
wherein f (V0, V1, …) and g (V0, V1, …) are linear functions of V0, V1, … Vn.
6. The method of claim 1, wherein the operation is stopped if the power is determined not to converge according to a convergence criterion.
7. The method of claim 1, wherein the network constraint is:
YV[0]＝0，
where Y is the admittance matrix and V0 is the complex node voltage.
8. The utility model provides a pure embedding trend device of three-phase active power distribution network which characterized in that includes:
the model establishing module is used for establishing a three-phase active power distribution network model, and the three-phase active power distribution network model comprises a three-phase bus and a computing node;
the load flow calculation module is used for carrying out load flow calculation on the three-phase bus and the calculation node under the network constraint condition to obtain power;
the first processing module is used for judging whether the stepping voltage regulator exceeds the voltage limit or not if the power convergence is judged and obtained according to the convergence criterion value;
and the second processing module is used for acquiring a load flow calculation result if the step voltage regulator is judged and known not to exceed the voltage limit.
9. An electronic device, comprising a memory and a processor, wherein the processor and the memory communicate with each other via a bus; the memory stores program instructions executable by the processor, the processor invoking the program instructions to perform the method of any of claims 1 to 7.
10. A non-transitory computer-readable storage medium, on which a computer program is stored, wherein the computer program, when being executed by a processor, implements a method for fully-embedded power flow in a three-phase active power distribution network according to any one of claims 1 to 7.
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