CN111181153A - Method and system for determining Thevenin equivalent parameters based on branch response information - Google Patents
Method and system for determining Thevenin equivalent parameters based on branch response information Download PDFInfo
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- CN111181153A CN111181153A CN201911141762.2A CN201911141762A CN111181153A CN 111181153 A CN111181153 A CN 111181153A CN 201911141762 A CN201911141762 A CN 201911141762A CN 111181153 A CN111181153 A CN 111181153A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
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Abstract
The invention discloses a method and a system for determining Thevenin equivalent parameters based on branch response information, and belongs to the technical field of voltage stability online analysis and monitoring of safety and stability of an electric power system. The method comprises the following steps: selecting any one of a plurality of buses in the power system as a boundary, and taking a part in the buses as a target to be detected; acquiring a voltage amplitude, active power and reactive power of a target bus node to be detected; acquiring thevenin internal potential amplitude, thevenin internal potential phase angle and thevenin reactance of the power system with iteration rounds of t and t + 1; determining whether the absolute values of the difference values of the Thevenin internal potential amplitude, the Thevenin internal potential phase angle and the Thevenin reactance of the power system with the iteration round number t and the t +1 round are smaller than a preset value; and determining the Thevenin internal potential amplitude, the Thevenin internal potential phase angle and the Thevenin reactance of the power system with the iteration round number of t +1 rounds as Thevenin equivalent parameters of the power system. The invention ensures the voltage stability of the power system.
Description
Technical Field
The invention relates to the technical field of voltage stability online analysis and monitoring of safety and stability of a power system, in particular to a method and a system for determining Thevenin equivalent parameters based on branch response information.
Background
Most provincial power grids in the eastern region of China are receiving-end power grids. In order to ensure that the receiving-end power grid can operate safely and reliably without voltage collapse, online voltage stability monitoring and analysis are required. Thevenin equivalent of an electric power system is a basic technology for realizing online voltage stability monitoring and analysis.
Thevenin equivalence equates an arbitrarily selected sub-network in a power system to the form of a series connection of an internal potential and a reactance. Thevenin equivalence can effectively simplify a complex power system, and can also accurately indicate the voltage stability and stability margin of the power system by using equivalent internal potential and internal impedance obtained by the equivalent internal potential and the equivalent internal impedance, so that effective perception of a dispatcher on the safety situation of a power grid is promoted, and voltage instability of the system is prevented. The Thevenin equivalent parameters are closely related to the power grid structure and the system operation mode and change along with the power grid structure and the system operation mode, and the accuracy of the Thevenin equivalent parameters directly determines the accuracy of recognizing the safety characteristics of the power grid by a dispatcher, so that the accurate determination of the Thevenin equivalent parameters under various working conditions is related to the correct judgment of the voltage stability of the power grid, and the Thevenin equivalent parameters are extremely important work.
The traditional Thevenin equivalent parameter determination method is suitable for the following scenes: during a plurality of adjacent time steps of continuous sampling, the amplitude value of the internal potential, the phase angle of the internal potential and the Thevenin reactance of a selected certain sub-network are kept unchanged; at the same time, the active, reactive, and voltage amplitudes of the external networks outside the sub-network need to change significantly between these adjacent time steps.
In fact, the actual operation condition of the power system is often greatly different from the above-mentioned scenario. A typical scenario is: in a plurality of time steps of Thevenin equivalence, which are carried out on a certain sub-network of an electric power system, in order to adjust the voltage level of the system to keep the voltage level in a reasonable range, the switching operation of reactive equipment (inductor or capacitor) often exists in an external network except the sub-network. Under the scene, the Thevenin equivalent internal potential of the sub-network can be changed obviously, and the traditional method has larger error and is not applicable any more.
The traditional method can be used only in the scene that the magnitude of thevenin internal potential, the phase angle of the internal potential and thevenin reactance are kept unchanged in a plurality of adjacent time steps. Under the working condition that the potential amplitude in thevenin changes, thevenin equivalent parameters obtained by the traditional method have poor precision and are difficult to support and accurately judge the voltage stability.
Disclosure of Invention
Aiming at the problems, the invention provides a method for determining thevenin equivalent parameters based on branch response information, which comprises the following steps:
selecting any one of a plurality of buses in the power system as a boundary, and taking a part in the buses as a target to be detected;
according to the preset time steps, acquiring the voltage amplitude of a target bus node to be detected, the active power of a target bus line to be detected and the reactive power of the target bus line to be detected;
according to the amplitude to be subjected to voltage, the active power and the reactive power, iteration is carried out on the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin, the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin are obtained, the number of iteration rounds t and t +1 rounds are obtained, and t is larger than or equal to 1;
obtaining the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin in the iteration rounds t and t +1, and determining whether the absolute value of the difference value of the internal potential amplitudes, the absolute value of the internal potential phase angle difference and the absolute value of the difference value of the Thevenin reactance of the power system Thevenin in the iteration rounds t and t +1 are smaller than a preset value or not;
and when the absolute value of the difference value of the internal potential amplitude value of the power system Thevenin, the absolute value of the internal potential phase angle difference value and the absolute value of the difference value of the reactance of the iteration round number t and the iteration round number t +1 are all smaller than preset values, determining the internal potential amplitude value of the power system Thevenin, the internal potential phase angle and the reactance of the iteration round number t +1 as equivalent parameters of the power system Thevenin.
Optionally, the preset time step is greater than or equal to 2.
Optionally, the preset value is 0.001.
Optionally, the thevenin internal potential amplitude, the thevenin internal potential phase angle and the power system thevenin reactance of the iteration round number t and the t +1 round are obtained, specifically:
iteration is carried out by enabling the Dyvenin internal potential amplitude of the power system in 1 iteration round number to be 1, the Dyvenin internal potential phase angle of the power system in 1 iteration round number to be 0 and the Dyvenin reactance of the power system in 1 iteration round number to be 0, and the Dyvenin internal potential amplitude of the power system, the Dyvenin internal potential phase angle of the power system and the Dyvenin reactance of the power system in t iteration round number are obtained;
according to the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t, the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t +1 are obtained, and the formula is as follows:
wherein η is 0.001-0.01,
The number of iteration rounds is t +1 round, namely the magnitude and delta of the Thevenin internal potential of the power systemth(t +1) iteration round number t +1 round of power system Thevenin internal potential phase angle Xth(t +1) iterative turns t +1 turns of Thevenin reactance of power system,
The internal potential amplitude value delta of the Thevenin of the power system is t rounds of iterationth(t) iterative round number t round power system Thevenin internal potential phase angle Xth(t) iterative turns t turns of Thevenin reactance, U of power systemkVoltage amplitude, P, of a bus node of a target to be measuredkFor the active power, Q, of the target busbar line to be testedkFor the reactive power of the target bus line to be measured, K is a preset time step, K is any one time step, fkAs the sum of the active residuals ekIs a reactive residual.
The invention also provides a system for determining Thevenin equivalent parameters based on branch response information, which comprises the following steps:
the target determining module selects any one of the buses in the power system as a boundary, and takes the part in the buses as a target to be detected;
the parameter acquisition module is used for acquiring the voltage amplitude of a node of a target bus to be detected, the active power of a target bus line to be detected and the reactive power of the target bus line to be detected according to a preset time step;
the iteration module is used for iterating the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin according to the amplitude to be voltage, the active power and the reactive power to obtain the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin of iteration rounds t and t +1, wherein t is greater than or equal to 1;
the comparison module is used for obtaining the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin in the iteration rounds t and t +1, and determining whether the absolute value of the difference value of the internal potential amplitude values of the power system Thevenin, the absolute value of the difference value of the internal potential phase angles of the power system Thevenin and the absolute value of the difference value of the Thevenin reactance of the power system are smaller than a preset value or not;
and the judgment module is used for determining that the Thevenin internal potential amplitude, the internal potential phase angle and the reactance of the power system in the iteration round number t +1 are equivalent parameters of the power system when the absolute value of the difference value of the Thevenin internal potential amplitude, the absolute value of the internal potential phase angle difference and the absolute value of the difference value of the reactance of the power system in the iteration round number t +1 are smaller than preset values.
Optionally, the preset time step is greater than or equal to 2.
Optionally, the preset value is 0.001.
Optionally, the iteration module is configured to:
iteration is carried out by enabling the Dyvenin internal potential amplitude of the power system in 1 iteration round number to be 1, the Dyvenin internal potential phase angle of the power system in 1 iteration round number to be 0 and the Dyvenin reactance of the power system in 1 iteration round number to be 0, and the Dyvenin internal potential amplitude of the power system, the Dyvenin internal potential phase angle of the power system and the Dyvenin reactance of the power system in t iteration round number are obtained;
according to the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t, the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t +1 are obtained, and the formula is as follows:
wherein η is 0.001-0.01,
The number of iteration rounds is t +1 round, namely the magnitude and delta of the Thevenin internal potential of the power systemth(t +1) iteration round number t +1 round of power system Thevenin internal potential phase angle Xth(t +1) iterative turns t +1 turns of Thevenin reactance of power system,
The internal potential amplitude value delta of the Thevenin of the power system is t rounds of iterationth(t) iterative round number t round power system Thevenin internal potential phase angle Xth(t) iterative turns t turns of Thevenin reactance, U of power systemkVoltage amplitude, P, of a bus node of a target to be measuredkFor the active power, Q, of the target busbar line to be testedkFor the reactive power of the target bus line to be measured, K is a preset time step, K is any one time step, fkAs the sum of the active residuals ekIs a reactive residual.
The method can obtain accurate Thevenin equivalent parameters, thereby supporting accurate voltage stability judgment, improving the effective perception of dispatching personnel on the safety situation of the power grid, preventing the voltage instability of the power system and ensuring the voltage stability of the power system.
According to the method, Thevenin equivalent parameters are calculated only by using local measurement data on the bus and the outgoing line thereof, a system model and parameters are not depended on, and the Thevenin equivalent parameters obtained by the method are more accurate compared with the traditional method for the working condition of the change of the internal potential amplitude of Thevenin.
Drawings
FIG. 1 is a flow chart of a method of determining Thevenin equivalent parameters based on branch response information according to the present invention;
FIG. 2 is a Thevenin equivalence diagram of an electric power system of the method for determining Thevenin equivalence parameters based on branch response information;
FIG. 3 is a graph showing an active power curve of a target busbar line to be tested and a reactive power curve of the target busbar line to be tested according to the method for determining Thevenin equivalent parameters based on branch response information;
FIG. 4 is a voltage amplitude curve diagram of a target bus node to be measured by the method for determining Thevenin equivalent parameters based on branch response information;
FIG. 5 is a Thevenin internal potential amplitude curve diagram of a power system of the method for determining Thevenin equivalent parameters based on branch response information;
FIG. 6 is a Thevenin internal potential phase angle graph of a power system of the method for determining Thevenin equivalent parameters based on branch response information of the invention;
FIG. 7 is a Thevenin reactance graph of a force system of a method for determining Thevenin equivalent parameters based on branch response information according to the present invention;
FIG. 8 is a diagram of a system for determining Thevenin equivalent parameters based on branch response information in accordance with the present invention.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
The invention provides a method for determining Thevenin equivalent parameters based on branch response information, which comprises the following steps of:
the thevenin equivalent diagram of the power system is shown in fig. 2, any one of a plurality of buses in the power system is selected as a boundary, the part inside the bus is used as a target to be detected, the target to be detected is a subsystem, the boundary outside the subsystem is used as an external system, and U is adoptedkVoltage amplitude, P, of a bus node of a target to be measuredkFor the active power, Q, of the target busbar line to be testedkThe reactive power of the target bus line to be measured,
For the magnitude, delta, of the Thevenin internal potential of the power systemthThevenin internal potential phase angle and X of power systemthIs a Thevenin reactance of a wheel power system;
according to the preset time step, the preset time step is more than or equal to 2;
the voltage amplitude of the target bus node to be detected and the active power of the target bus line to be detected are obtained, and the voltage amplitude of the target bus node to be detected and the active power curve of the target bus line to be detected are shown in fig. 3;
obtaining the reactive power of a target busbar line to be tested, wherein a reactive power curve chart of the target busbar line to be tested is shown in fig. 4;
iterating the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system according to the voltage amplitude of the target bus node to be detected, the active power of the target bus line to be detected and the reactive power of the target bus line to be detected, and acquiring the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system for t +1 rounds of iteration rounds, wherein t is greater than or equal to 1;
the method comprises the following steps of obtaining thevenin internal potential amplitude, thevenin internal potential phase angle and power system thevenin reactance of iteration rounds t and t +1, and specifically comprises the following steps:
iteration is carried out by enabling the Dyvenin internal potential amplitude of the power system in 1 iteration round number to be 1, the Dyvenin internal potential phase angle of the power system in 1 iteration round number to be 0 and the Dyvenin reactance of the power system in 1 iteration round number to be 0, and the Dyvenin internal potential amplitude of the power system, the Dyvenin internal potential phase angle of the power system and the Dyvenin reactance of the power system in t iteration round number are obtained;
according to the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t, the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t +1 are obtained, and the formula is as follows:
wherein η is 0.001-0.01,
The number of iteration rounds is t +1 round, namely the magnitude and delta of the Thevenin internal potential of the power systemth(t +1) iteration round number t +1 round of power system Thevenin internal potential phase angle Xth(t +1) iterative turns t +1 turns of Thevenin reactance of power system,
The internal potential amplitude value delta of the Thevenin of the power system is t rounds of iterationth(t) iterative round number t round power system Thevenin internal potential phase angle Xth(t) iterative turns t turns of Thevenin reactance, U of power systemkVoltage amplitude, P, of a bus node of a target to be measuredkFor the active power, Q, of the target busbar line to be testedkFor the reactive power of the target bus line to be measured, K is a preset time step, K is any one time step, fkAs the sum of the active residuals ekIs a reactive residual.
Acquiring the internal potential amplitude value of the power system Thevenin, the internal potential phase angle of the power system Thevenin and the Thevenin reactance of the power system according to the iteration turns t and t +1, and determining whether the absolute value of the difference value of the internal potential amplitude values of the power system Thevenin, the absolute value of the difference value of the internal potential phase angles of the power system Thevenin and the absolute value of the difference value of the Thevenin reactance of the power system Thevenin of the iteration turns t and t +1 are smaller than a preset value or not;
when the absolute value of the difference value of the internal potential amplitude value of the power system Thevenin, the absolute value of the phase angle difference value of the internal potential of the power system Thevenin and the absolute value of the difference value of the Thevenin reactance of the power system, which are the iteration turns t and t +1, are all smaller than preset values, the preset values are 0.001, and the internal potential amplitude value of the power system Thevenin, the internal potential phase angle of the power system Thevenin and the Thevenin reactance of the power system, which are the iteration turns t +1, are determined as equivalent parameters of the Thevenin of the power system;
graphs of the magnitude of the Thevenin internal potential of the power system, the phase angle of the Thevenin internal potential of the power system, and the Thevenin reactance of the power system are shown in FIGS. 5, 6, and 7, respectively.
The present invention further provides a system 200 for determining thevenin equivalent parameters based on branch response information, as shown in fig. 8, comprising:
the target determining module 201 selects any one of a plurality of buses in the power system as a boundary, and takes a part in the buses as a target to be detected;
the parameter obtaining module 202 is used for obtaining the voltage amplitude of the node of the target bus to be detected, the active power of the target bus line to be detected and the reactive power of the target bus line to be detected according to the preset time step, wherein the preset time step is greater than or equal to 2;
the iteration module 203 is used for iterating the Thevenin internal potential amplitude value of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system according to the voltage amplitude value of the target bus node to be detected, the active power of the target bus line to be detected and the reactive power of the target bus line to be detected, and acquiring the Thevenin internal potential amplitude value of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system in t +1 iteration rounds, wherein t is greater than or equal to 1;
the iteration module 203 is configured to:
iteration is carried out by enabling the Dyvenin internal potential amplitude of the power system in 1 iteration round number to be 1, the Dyvenin internal potential phase angle of the power system in 1 iteration round number to be 0 and the Dyvenin reactance of the power system in 1 iteration round number to be 0, and the Dyvenin internal potential amplitude of the power system, the Dyvenin internal potential phase angle of the power system and the Dyvenin reactance of the power system in t iteration round number are obtained;
according to the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t, the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t +1 are obtained, and the formula is as follows:
wherein η is 0.001-0.01,
The number of iteration rounds is t +1 round, namely the magnitude and delta of the Thevenin internal potential of the power systemth(t +1) iteration round number t +1 round of power system Thevenin internal potential phase angle Xth(t +1) iterative turns t +1 turns of Thevenin reactance of power system,
The internal potential amplitude value delta of the Thevenin of the power system is t rounds of iterationth(t) iterative round number t round power system Thevenin internal potential phase angle Xth(t) iterative turns t turns of Thevenin reactance, U of power systemkVoltage amplitude, P, of a bus node of a target to be measuredkFor the active power, Q, of the target busbar line to be testedkFor the reactive power of the target bus line to be measured, K is a preset time step, K is any one time step, fkAs the sum of the active residuals ekIs a reactive residual.
The comparison module 204 is used for obtaining the internal potential amplitude value of the power system thevenin, the internal potential phase angle of the power system thevenin and the thevenin reactance of the power system according to iteration rounds t and t +1, and determining whether the absolute value of the difference value of the internal potential amplitude values of the power system thevenin, the absolute value of the difference value of the internal potential phase angle of the power system thevenin and the absolute value of the difference value of the thevenin reactance of the power system are smaller than a preset value or not;
the judgment module 205 determines that when the absolute value of the difference value of the internal potential amplitude of the power system thevenin, the absolute value of the phase angle difference value of the internal potential of the power system thevenin and the absolute value of the difference value of the thevenin reactance of the power system are all smaller than preset values, the preset values are 0.001, and determines that the internal potential amplitude of the power system thevenin, the internal potential phase angle of the power system thevenin and the thevenin reactance of the power system thevenin in the iteration round t +1 are equivalent parameters of the power system thevenin.
The method can obtain accurate Thevenin equivalent parameters, thereby supporting accurate voltage stability judgment, improving the effective perception of dispatching personnel on the safety situation of the power grid, preventing the voltage instability of the system and ensuring the voltage stability of the power system.
According to the method, Thevenin equivalent parameters are calculated only by using local measurement data on the bus and the outgoing line thereof, a system model and parameters are not depended on, and the Thevenin equivalent parameters obtained by the method are more accurate compared with the traditional method for the working condition of the change of the internal potential amplitude of Thevenin.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (8)
1. A method of determining thevenin equivalent parameters based on branch response information, the method comprising:
selecting any one of a plurality of buses in the power system as a boundary, and taking a part in the buses as a target to be detected;
according to the preset time steps, acquiring the voltage amplitude of a target bus node to be detected, the active power of a target bus line to be detected and the reactive power of the target bus line to be detected;
according to the amplitude to be subjected to voltage, the active power and the reactive power, iteration is carried out on the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin, the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin are obtained, the number of iteration rounds t and t +1 rounds are obtained, and t is larger than or equal to 1;
obtaining the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin in the iteration rounds t and t +1, and determining whether the absolute value of the difference value of the internal potential amplitudes, the absolute value of the internal potential phase angle difference and the absolute value of the difference value of the Thevenin reactance of the power system Thevenin in the iteration rounds t and t +1 are smaller than a preset value or not;
and when the absolute value of the difference value of the internal potential amplitude value of the power system Thevenin, the absolute value of the internal potential phase angle difference value and the absolute value of the difference value of the reactance of the iteration round number t and the iteration round number t +1 are all smaller than preset values, determining the internal potential amplitude value of the power system Thevenin, the internal potential phase angle and the reactance of the iteration round number t +1 as equivalent parameters of the power system Thevenin.
2. The method of claim 1, the preset time step being greater than or equal to 2.
3. The method of claim 1, wherein the preset value is 0.001.
4. The method according to claim 1, wherein the obtaining of thevenin internal potential amplitude, thevenin internal potential phase angle and power system thevenin reactance of iteration rounds t and t +1 is specifically as follows:
iteration is carried out by enabling the Dyvenin internal potential amplitude of the power system in 1 iteration round number to be 1, the Dyvenin internal potential phase angle of the power system in 1 iteration round number to be 0 and the Dyvenin reactance of the power system in 1 iteration round number to be 0, and the Dyvenin internal potential amplitude of the power system, the Dyvenin internal potential phase angle of the power system and the Dyvenin reactance of the power system in t iteration round number are obtained;
according to the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t, the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t +1 are obtained, and the formula is as follows:
wherein η is 0.001-0.01,
The number of iteration rounds is t +1 round, namely the magnitude and delta of the Thevenin internal potential of the power systemth(t +1) iteration round number t +1 round of power system Thevenin internal potential phase angle Xth(t +1) iterative turns t +1 turns of Thevenin reactance of power system,
The internal potential amplitude value delta of the Thevenin of the power system is t rounds of iterationth(t) iterative round number t round power system Thevenin internal potential phase angle Xth(t) iterative turns t turns of Thevenin reactance, U of power systemkVoltage amplitude, P, of a bus node of a target to be measuredkFor the active power, Q, of the target busbar line to be testedkThe reactive power of a target bus line to be measured, K is a preset time step, K is any one time step,fkAs the sum of the active residuals ekIs a reactive residual.
5. A system for determining thevenin equivalent parameters based on branch response information, the system comprising:
the target determining module selects any one of the buses in the power system as a boundary, and takes the part in the buses as a target to be detected;
the parameter acquisition module is used for acquiring the voltage amplitude of a node of a target bus to be detected, the active power of a target bus line to be detected and the reactive power of the target bus line to be detected according to a preset time step;
the iteration module is used for iterating the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin according to the amplitude to be voltage, the active power and the reactive power to obtain the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin of iteration rounds t and t +1, wherein t is greater than or equal to 1;
the comparison module is used for obtaining the internal potential amplitude, the internal potential phase angle and the reactance of the power system Thevenin in the iteration rounds t and t +1, and determining whether the absolute value of the difference value of the internal potential amplitude values of the power system Thevenin, the absolute value of the difference value of the internal potential phase angles of the power system Thevenin and the absolute value of the difference value of the Thevenin reactance of the power system are smaller than a preset value or not;
and the judgment module is used for determining that the Thevenin internal potential amplitude, the internal potential phase angle and the reactance of the power system in the iteration round number t +1 are equivalent parameters of the power system when the absolute value of the difference value of the Thevenin internal potential amplitude, the absolute value of the internal potential phase angle difference and the absolute value of the difference value of the reactance of the power system in the iteration round number t +1 are smaller than preset values.
6. The system of claim 5, the preset time step is greater than or equal to 2.
7. The system of claim 5, wherein the preset value is 0.001.
8. The system of claim 5, the iteration module to:
iteration is carried out by enabling the Dyvenin internal potential amplitude of the power system in 1 iteration round number to be 1, the Dyvenin internal potential phase angle of the power system in 1 iteration round number to be 0 and the Dyvenin reactance of the power system in 1 iteration round number to be 0, and the Dyvenin internal potential amplitude of the power system, the Dyvenin internal potential phase angle of the power system and the Dyvenin reactance of the power system in t iteration round number are obtained;
according to the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t, the Thevenin internal potential amplitude of the power system, the Thevenin internal potential phase angle of the power system and the Thevenin reactance of the power system of the iteration round number t +1 are obtained, and the formula is as follows:
wherein η is 0.001-0.01,
The number of iteration rounds is t +1 round, namely the magnitude and delta of the Thevenin internal potential of the power systemth(t +1) iteration round number t +1 round of power system Thevenin internal potential phase angle Xth(t +1) iterative round number t +1 round power system maintenanceA south reactance,
The internal potential amplitude value delta of the Thevenin of the power system is t rounds of iterationth(t) iterative round number t round power system Thevenin internal potential phase angle Xth(t) iterative turns t turns of Thevenin reactance, U of power systemkVoltage amplitude, P, of a bus node of a target to be measuredkFor the active power, Q, of the target busbar line to be testedkFor the reactive power of the target bus line to be measured, K is a preset time step, K is any one time step, fkAs the sum of the active residuals ekIs a reactive residual.
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