CN116760037A - Flexible interconnected three-phase four-wire system distribution network power flow calculation method, device and equipment - Google Patents

Flexible interconnected three-phase four-wire system distribution network power flow calculation method, device and equipment Download PDF

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Publication number
CN116760037A
CN116760037A CN202310642154.XA CN202310642154A CN116760037A CN 116760037 A CN116760037 A CN 116760037A CN 202310642154 A CN202310642154 A CN 202310642154A CN 116760037 A CN116760037 A CN 116760037A
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China
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power
data
current
node
phase
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Inventor
白浩
付宇
肖小兵
李巍
袁小清
李跃
杨炜晨
贯昌宝
瞿杨全
徐敏
方阳
叶远红
刘通
宋子宏
姜方向
郭琦
宾峰
李阳
要若天
杨凛
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CSG Electric Power Research Institute
Guizhou Power Grid Co Ltd
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CSG Electric Power Research Institute
Guizhou Power Grid Co Ltd
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Priority to CN202310642154.XA priority Critical patent/CN116760037A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/04—Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
    • H02J3/06—Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

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

Abstract

The application relates to a method, a device and equipment for calculating the power flow of a flexible interconnected three-phase four-wire system power distribution network, wherein the method comprises the steps of obtaining first power data, and calculating a first alternating current circuit of the flexible interconnected three-phase four-wire system power distribution network in a forward push back substitution power flow calculation mode according to the first power data to obtain first power flow data; acquiring second power data, loss power of the converter and third power data of the converter, and calculating fourth power data according to the second power data, the third power data and the loss power; and calculating a second alternating current line of the tide of the flexible interconnection three-phase four-wire system power distribution network according to the fourth power data by adopting a forward push back substitution tide calculation mode to obtain second tide data. According to the method, the power data are obtained, and the power calculation is respectively carried out on the first alternating current line and the second alternating current line in a forward push back power flow calculation mode, so that the calculation result reduces errors of a power flow theory and an actual power flow of the three-phase four-wire system power distribution network which are flexibly connected, and the precision of the power flow calculation result is improved.

Description

Flexible interconnected three-phase four-wire system distribution network power flow calculation method, device and equipment
Technical Field
The application relates to the technical field of power flow analysis of power distribution networks, in particular to a power flow calculation method, device and equipment of a three-phase four-wire system power distribution network which are flexibly connected.
Background
Solves the serious environmental problems caused by the huge consumption of fossil energy, and builds a clean and efficient novel energy system, which becomes the primary direction of the current power system development. The novel energy system is built, a large amount of clean energy sources such as photovoltaic energy, wind energy and the like are required to be accessed, and the utilization efficiency of the clean energy sources is improved.
With the continuous development of photovoltaic power generation technology, the technical difficulty of photovoltaic power generation is continuously overcome, the cost of photovoltaic power generation is also continuously reduced, and renewable energy power generation represented by photovoltaic power generation is one of the important directions of current energy utilization. However, a large number of accesses of the distributed photovoltaic power stations also bring some problems to the power distribution network, and the problems of voltage out-of-limit, power flow foldback and the like of the power distribution network are easy to occur due to the characteristics of randomness of photovoltaic output, mismatching of output and load time sequence and the like. The low-voltage power distribution network adopts a three-phase four-wire system circuit structure, so that the three-phase unbalance phenomenon is generated under the conditions of asymmetric access of three-phase loads and asymmetric parameters of the circuit, and the three-phase unbalance of the low-voltage power distribution network is further aggravated by large-scale single-phase grid connection of photovoltaic. In addition, in order to improve the photovoltaic digestion capability, the in-situ digestion of the photovoltaic output is realized, a plurality of power distribution networks at present adopt a flexible interconnection mode, two alternating current power networks are connected through an inverter, the photovoltaic output is transmitted through a direct current circuit, and the photovoltaic digestion rate is improved. The access of the converters further changes the flow direction of the power in the distribution network.
For the power distribution network in the balanced state, the transformer, the power line, the parallel capacitor, the load and the like in the default power distribution network are three-phase symmetrical, so that the power flow of the power distribution network can be calculated according to a single-phase line model. However, at present, the low-voltage power distribution network is actually a three-phase four-wire system circuit, the three-phase three-wire system circuit and the three-phase four-wire system circuit have essential differences in terms of load flow calculation modes and the like, the parameters of the low-voltage power distribution network circuit are asymmetric, a large amount of loads are single-phase access rather than three-phase access, the three-phase imbalance of the low-voltage power distribution network is further aggravated by large-scale photovoltaic single-phase grid connection, the three-phase imbalance can not be accurately reflected by adopting a three-phase three-wire system single-phase circuit model, and errors can exist when the circuit loss is calculated.
Disclosure of Invention
The embodiment of the application provides a method, a device and equipment for calculating the power flow of a flexibly-interconnected three-phase four-wire system power distribution network, which are used for solving the technical problem that the power flow calculation mode of the existing power distribution network has large calculation result error due to three-phase unbalance of the three-phase four-wire system power distribution network.
In order to achieve the above object, the embodiment of the present application provides the following technical solutions:
On the one hand, the utility model provides a flexible interconnected three-phase four-wire system distribution network power flow calculation method, which comprises the following steps:
acquiring first power data of converter operation in a three-phase four-wire system power distribution network controlled by P-Q, and calculating a first alternating current circuit of a flexible interconnection three-phase four-wire system power distribution network in a forward push back substitution power flow calculation mode according to the first power data to obtain first power flow data;
acquiring second power data output by the first alternating current line, loss power of the converter and third power data of the converter, and calculating according to the second power data, the third power data and the loss power to obtain fourth power data;
and calculating a second alternating current line of the flexible interconnection three-phase four-wire system power distribution network tide according to the fourth power data in a forward push back substitution tide calculation mode to obtain second tide data.
Preferably, the content of the forward push back power flow calculation mode includes:
s01, acquiring electrical quantity parameters of m nodes of a first alternating current line or a second alternating current line in a flexible interconnection three-phase four-wire system power distribution network in real time, wherein the electrical quantity parameters comprise first current, voltage amplitude and impedance data; according to the voltage amplitude value of each node and the first power data or the fourth power data, three-phase load current of a section line corresponding to each node is obtained;
S02, calculating according to the first current of the three phases of the end node to obtain the first neutral line current of the end node; according to the first current corresponding to each node and the three-phase load current of the line where the first current is positioned, adopting a forward superposition mode to calculate to obtain the three-phase current of the first line; according to the first neutral line current and the three-phase load current of the section line where each node corresponds to, calculating to obtain a second neutral line current of each node except the last node;
s03, according to the impedance data of the electrical quantity parameters, the voltage amplitude of the first node, the first current and the second neutral line current of each node, pushing back and calculating to obtain the voltage of the last node;
s04, acquiring electrical quantity parameters of m nodes of a first alternating current circuit or a second alternating current circuit of the flexible interconnection three-phase four-wire system power distribution network again, performing iterative computation by adopting forward-push back power flow from the step S01 to the step S03 until a voltage difference value of two adjacent end node voltages meets a convergence condition, and correcting the node voltages obtained by iterative computation to obtain voltage data of the power flow computation of the flexible interconnection three-phase four-wire system power distribution network.
Preferably, the calculating according to the voltage amplitude value and the first power data or the fourth power data of each node, to obtain the three-phase load current of the section line corresponding to each node includes:
According to the voltage amplitude of each node and the first power data or the fourth power data, a three-phase load current formula is adopted to calculate, so that three-phase load currents of a section of line corresponding to each node are obtained;
wherein, the three-phase load current formula is:
wherein P is i The active power input to the section line corresponding to the ith node, qi is the reactive power input to the section line corresponding to the ith node, U i For the voltage amplitude of the ith node, I load，i And a, b and c are respectively three phases a, b and c of a three-phase four-wire system for the load current of the line of the corresponding section of the ith node.
Preferably, the content of the forward push back power flow calculation mode further includes:
calculating by adopting a neutral current calculation formula according to the first current of the three phases of the end node to obtain the first neutral line current of the end node;
according to the first current corresponding to each node and the three-phase load current of the section line where the first current is positioned, adopting a forward superposition mode to calculate a first section line current calculation formula, and obtaining the three-phase current of the first section line;
calculating by adopting a KCL law formula according to the first neutral line current and the three-phase load current of the section line where each node corresponds to, and obtaining a second neutral line current of each node except the last node;
Wherein, the neutral current calculation formula is:
the first section line current calculation formula is as follows:
the formula of KCL law is as follows:
in the method, in the process of the invention,three-phase flows of a, b and c respectivelyFirst current after passing through the mth line, < >>First neutral current for the end node, +.>The current of a, b and c three phases flowing through the first-stage line is respectively +.>Respectively, a, b and c three phases are respectively first current after flowing through the ith section line, +.> Load current of a, b and c three phases flowing through the ith section of line respectively, +.>A second neutral current that is the neutral of the ith node.
Preferably, the content of the forward push back power flow calculation mode further includes:
according to the impedance data of the electrical quantity parameters, the voltage amplitude of the first node, the three-phase load current of the section line corresponding to each node and the second neutral line current, a voltage calculation formula is adopted to carry out backward calculation, and the final node voltage is obtained;
the voltage calculation formula is as follows:
in the method, in the process of the invention,respectively, a, b and c three phases are respectively first current after flowing through the ith section line, +.>Second neutral current, which is the neutral line of the ith node,/>Impedance data on the i-th section of the three phases a, b and c respectively, < >>Impedance data for neutral line of ith node, < +. > Voltage drop at the ith node for the three phases a, b, c and neutral line n, respectively,/->The terminal voltages of the three phases a, b, c and the neutral line n respectively,the voltage amplitudes of the three phases a, b and c and the n first nodes of the neutral line are respectively.
Preferably, correcting the voltage of each node obtained by iterative calculation to obtain voltage data of the power flow calculation of the flexible interconnection three-phase four-wire system power distribution network comprises the following steps: correcting the voltage of each node obtained by iterative calculation by adopting a correction formula to obtain voltage data of the power flow calculation of the flexible interconnection three-phase four-wire system power distribution network; the correction formula is:
in the method, in the process of the invention,the voltage amplitudes of the three phases a, b, c and the neutral line n at the ith node,respectively flexible interconnection threeAnd calculating three-phase voltage data by using the power flow of the phase four-wire system distribution network.
Preferably, the calculating according to the second power data, the third power data and the loss power, obtaining fourth power data includes:
calculating by adopting a first power calculation formula according to the third power data and the loss data to obtain fifth power data of the power distribution network injected by the converter controlled by the P-Q;
calculating by adopting a second power calculation formula according to the fifth power data and the second power data to obtain alternating current active data and alternating current reactive data of the fourth power data;
Calculating by adopting a third power calculation formula according to the third power data, the loss power and the second power data to obtain direct current active power of the fourth power data;
the first power calculation formula is as follows:
the second power calculation formula is:
the third power calculation formula is:
in the method, in the process of the invention,are respectively matched withAC line of electric network>Phase i node connects active power and reactive power of the converter, < >>Ac line for distribution network>The i-th node of the phase is connected with the loss power of the converter,active alternating current data and reactive alternating current data which are respectively fifth power data; />First ac line respectively->Active power and reactive power output by the ith node, namely second power data; />Second alternating current lines respectively->Active power and reactive power of the i-th node of the phase, namely alternating current power of fourth power data; />To inject active power of an inverter at an ith node of a power distribution network, P i 0+ For the active power of the i-th node in the second power data,/and/or>And the direct current power of the ith node in the fourth power data.
On the other hand, the utility model provides a flexible interconnected three-phase four-wire system distribution network power flow calculation device, which comprises a first power flow calculation module, a power calculation module and a second power flow calculation module;
The first power flow calculation module is used for obtaining first power data of the current converter operation in the three-phase four-wire system power distribution network controlled by adopting P-Q, and calculating a first alternating current line of the flexible interconnection three-phase four-wire system power distribution network in a forward push back substitution power flow calculation mode according to the first power data to obtain first power flow data;
the power calculation module is used for obtaining second power data output by the first alternating current circuit, loss power of the converter and third power data of the converter, and calculating according to the second power data, the third power data and the loss power to obtain fourth power data;
and the second power flow calculation module is used for calculating a second alternating current line of the flexible interconnection three-phase four-wire system power distribution network tide in a forward push back substitution power flow calculation mode according to the fourth power data to obtain second power flow data.
Preferably, the first power flow calculation module and the second power flow calculation module each comprise a first calculation sub-module, a second calculation sub-module, a third calculation sub-module and a fourth calculation sub-module;
the first calculation submodule is used for acquiring electrical quantity parameters of m nodes of a first alternating current line or a second alternating current line in the flexible interconnection three-phase four-wire system power distribution network in real time, wherein the electrical quantity parameters comprise first current, voltage amplitude and impedance data; according to the voltage amplitude value of each node and the first power data or the fourth power data, three-phase load current of a section line corresponding to each node is obtained;
The second calculation sub-module is used for calculating according to the first current of the three phases of the end node to obtain the first neutral line current of the end node; according to the first current corresponding to each node and the three-phase load current of the line where the first current is positioned, adopting a forward superposition mode to calculate to obtain the three-phase current of the first line; according to the first neutral line current and the three-phase load current of the section line where each node corresponds to, calculating to obtain a second neutral line current of each node except the last node;
the third calculation sub-module is used for performing backward pushing calculation according to the impedance data of the electrical quantity parameters, the voltage amplitude of the first node, the first current of each node and the second neutral line current to obtain the voltage of the last node;
the fourth calculation sub-module is configured to re-acquire electrical quantity parameters of m nodes of the first ac line or the second ac line of the flexible interconnected three-phase four-wire system power distribution network, and perform iterative calculation by adopting the forward push back substitution power flow of the first calculation sub-module, the second calculation sub-module and the third calculation sub-module until a voltage difference value of two adjacent terminal node voltages is obtained and meets a convergence condition, and correct the voltage of each node obtained by iterative calculation to obtain voltage data of the power flow calculation of the flexible interconnected three-phase four-wire system power distribution network.
In yet another aspect, a terminal device is provided that includes a processor and a memory;
the memory is used for storing program codes and transmitting the program codes to the processor;
and the processor is used for executing the flexible interconnected three-phase four-wire system power distribution network power flow calculation method according to the instructions in the program codes.
From the above technical solutions, the embodiment of the present application has the following advantages: the method comprises the steps of obtaining first power data of an inverter in a three-phase four-wire system power distribution network controlled by P-Q, and calculating a first alternating current circuit of the flexible interconnection three-phase four-wire system power distribution network in a forward push back substitution power flow calculation mode according to the first power data to obtain first power flow data; obtaining second power data output by the first alternating current line, loss power of the converter and third power data of the converter, and calculating according to the second power data, the third power data and the loss power to obtain fourth power data; and calculating a second alternating current line of the tide of the flexible interconnection three-phase four-wire system power distribution network in a forward push back power flow calculation mode according to the fourth power data to obtain second power flow data. According to the power flow calculation method of the flexibly-interconnected three-phase four-wire system power distribution network, power data are obtained, and the power flow calculation is respectively carried out on the first alternating current circuit and the second alternating current circuit of the flexibly-interconnected three-phase four-wire system power distribution network in a forward push back power flow calculation mode, so that the calculated result reduces errors of the power flow theory and the actual power flow theory of the flexibly-interconnected three-phase four-wire system power distribution network, and the precision of the power flow calculation result is improved. The technical problem that the calculation result error is large due to the fact that the three phases of a three-phase four-wire system power distribution network are unbalanced in the current power distribution network power flow calculation mode is solved.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the application, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.
Fig. 1 is a flow chart of steps of a power flow calculation method of a flexible interconnected three-phase four-wire system power distribution network according to an embodiment of the application;
fig. 2 is a schematic diagram of a flexibly-interconnected three-phase four-wire system power distribution network in a flexibly-interconnected three-phase four-wire system power distribution network power flow calculation method according to an embodiment of the application;
fig. 3 is a schematic diagram of an ac line of a flexibly-interconnected three-phase four-wire system power distribution network in a power flow calculation method of the flexibly-interconnected three-phase four-wire system power distribution network according to an embodiment of the present application;
fig. 4 is a flowchart illustrating a step of a forward push back power flow calculation mode in a power flow calculation method of a flexible interconnected three-phase four-wire system power distribution network according to an embodiment of the present application;
fig. 5 is a schematic topology diagram of a flexibly-interconnected three-phase four-wire system power distribution network in a flexibly-interconnected three-phase four-wire system power distribution network power flow calculation method according to an embodiment of the present application;
Fig. 6 is a graph of an ac line voltage peak in a power flow calculation method of a flexible-interconnection three-phase four-wire system power distribution network according to an embodiment of the present application;
fig. 7 is a frame flow chart of a power flow calculation device of a flexible-interconnection three-phase four-wire system power distribution network according to an embodiment of the application.
Detailed Description
In order to make the objects, features and advantages of the present application more comprehensible, the technical solutions in the embodiments of the present application are described in detail below with reference to the accompanying drawings, and it is apparent that the embodiments described below are only some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In the description of embodiments of the present application, the terms "first," "second," and the like 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 defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the embodiments of the present application, the meaning of "plurality" is two or more, unless explicitly defined otherwise.
In the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like are to be construed broadly and include, for example, either permanently connected, removably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to specific circumstances.
The embodiment of the application provides a method, a device and equipment for calculating the power flow of a flexibly-interconnected three-phase four-wire system power distribution network, which are used for solving the technical problem that the error of a calculation result is large due to the unbalance of three phases of the three-phase four-wire system power distribution network in the existing power flow calculation mode of the power distribution network.
Embodiment one:
fig. 1 is a flow chart of steps of a power flow calculation method of a flexibly-interconnected three-phase four-wire system power distribution network according to an embodiment of the present application, and fig. 2 is a schematic diagram of the flexibly-interconnected three-phase four-wire system power distribution network in the power flow calculation method of the flexibly-interconnected three-phase four-wire system power distribution network according to the embodiment of the present application.
As shown in fig. 1, the embodiment of the application provides a power flow calculation method of a flexible interconnected three-phase four-wire system power distribution network, which comprises the following steps:
s1, first power data of converter operation in a three-phase four-wire system power distribution network controlled by P-Q is obtained, and first power flow data is obtained by calculating a first alternating current line of a flexible interconnection three-phase four-wire system power distribution network in a forward push back substitution power flow calculation mode according to the first power data.
In step S1, first power data for controlling the operation of the converter in the three-phase four-wire system power distribution network by using the P-Q is obtained, where the first power data includes ac active power, ac reactive power and dc active power; and secondly, calculating the first alternating current line of the flexible interconnection three-phase four-wire system power distribution network in a forward push back substitution power flow calculation mode according to the first power data, so as to realize power flow calculation of the first alternating current line of the flexible interconnection three-phase four-wire system power distribution network. In this embodiment, as shown in fig. 2, the flexible-interconnection three-phase four-wire system distribution network includes a first ac line and a second ac line, between which a first converter VSC1 and a second converter VSC2 connected to the first converter are disposed.
In the embodiment of the application, if the direct-current voltage class of the flexible interconnection three-phase four-wire system distribution network is + -300 kV, the capacity is 600 MVA. Calculating the loss power P of the converter by adopting a loss power calculation formula according to the alternating current flowing through the converter and the parameters of the converter VSC,loss The loss power calculation formula is:
wherein I is c For the alternating current flowing through the converter, A is a first loss coefficient proportional to the square of the alternating current, B is a second linear loss coefficient, C is a fixed loss and a converter no-load loss value, P c And Q c Active power and reactive power flowing through the converter respectively, SN is rated capacity of the converter, U DC,N Is a direct current voltage rating. Wherein C can be that the converter is in a rectifying state and is a loss coefficient when the power distribution network flows from the alternating current system to the direct current system. The rated running loss of the common two-level converter is about 3%, the loss of the MMC converter is about 1%, and the current loss of the converter can be selected to be 2% for load flow calculation.
In the embodiment of the application, the exchange power relationship of the alternating current and direct current distribution networks at the two ends of the converter is as follows:
wherein the sum of the active power of the ac side of the converter is equal to the sum of the active power of the dc side of the converter. In the method, in the process of the application, Active power respectively output by converters in three phases a, b and c of the power distribution network respectively>Is the alternating current active power of the converter, +.>Is the direct current active power of the converter, P 0+ 、P 0- The active power of the converter in the positive voltage direct current line and the active power of the converter in the negative voltage direct current line are respectively.
S2, obtaining second power data output by the first alternating current line, loss power of the converter and third power data of the converter, and calculating according to the second power data, the third power data and the loss power to obtain fourth power data.
In the step S2, data of power flow calculation performed by the second ac line of the flexible interconnected three-phase four-wire power distribution network is obtained, and when power flow calculation is performed by the flexible interconnected three-phase four-wire power distribution network, power of the node to be injected needs to be superimposed at the node to which the converter is connected in addition to power of the node to be injected when power of the node to be injected is calculated at each moment, and at this time, active power and reactive power of the node injection power can be substituted into the power flow to perform calculation.
In the embodiment of the present application, according to the second power data, the third power data and the loss power calculation, obtaining fourth power data includes:
Calculating by adopting a first power calculation formula according to the third power data and the loss data to obtain fifth power data of the power distribution network injected by the converter controlled by the P-Q;
calculating by adopting a second power calculation formula according to the fifth power data and the second power data to obtain alternating current active data and alternating current reactive data of fourth power data;
calculating by adopting a third power calculation formula according to the third power data, the loss power and the second power data to obtain direct current active power of fourth power data;
the first power calculation formula is as follows:
the second power calculation formula is:
the third power calculation formula is:
in the method, in the process of the invention,respectively is an alternating current line of a power distribution network>Phase i node connects active power and reactive power of the converter, < >>Ac line for distribution network>The i-th node of the phase is connected with the loss power of the converter,active alternating current data and reactive alternating current data which are respectively fifth power data; />First ac line respectively->Active power and reactive power output by the ith node, namely second power data; />Second alternating current lines respectively->Active power and reactive power of the i-th node of the phase, namely alternating current power of fourth power data; / >To inject active power of an inverter at an ith node of a power distribution network, P i 0+ Active power for the i-th node in the second power data,and the direct current power of the ith node in the fourth power data.
When the following is performedMore than 0, representing that active power in the converter flows from the alternating current side to the direct current side, and corresponds to a rectification process; when->And less than 0, indicating that the active power in the converter flows from the direct current side to the alternating current side, and corresponds to the inversion process. Because the flexible interconnection three-phase four-wire system distribution network carries out load flow calculation on the three-phase four-wire system line, the power injected into corresponding nodes by the converter is also calculated in a split phase mode, and the converter loss can be approximately regarded as equal distribution to the three-phase line. In this embodiment, in the process of calculating the dc active power of the fourth power data, the power allocated by the first ac line and the second ac line of the power distribution network may be the same, i.e., +.>Opposite to the AC side distribution network, < > a->When the temperature is more than 0, the rectification process is carried out; />Less than 0 is an inversion process.
S3, calculating a second alternating current line of the flexible interconnection three-phase four-wire system power distribution network tide according to the fourth power data in a forward push back substitution tide calculation mode, and obtaining second tide data.
In step S3, the dc power data and the ac power data of the fourth power data obtained in step S2 are calculated by adopting a forward-push back power flow calculation method, respectively, to obtain second power flow data composed of ac and dc.
The application provides a power flow calculation method of a flexible interconnected three-phase four-wire system power distribution network, which comprises the steps of obtaining first power data of an inverter running in the three-phase four-wire system power distribution network controlled by P-Q, and calculating a first alternating current circuit of the flexible interconnected three-phase four-wire system power distribution network in a forward push back substitution power flow calculation mode according to the first power data to obtain first power flow data; obtaining second power data output by the first alternating current line, loss power of the converter and third power data of the converter, and calculating according to the second power data, the third power data and the loss power to obtain fourth power data; and calculating a second alternating current line of the tide of the flexible interconnection three-phase four-wire system power distribution network in a forward push back power flow calculation mode according to the fourth power data to obtain second power flow data. According to the power flow calculation method of the flexibly-interconnected three-phase four-wire system power distribution network, power data are obtained, and the power flow calculation is respectively carried out on the first alternating current circuit and the second alternating current circuit of the flexibly-interconnected three-phase four-wire system power distribution network in a forward push back power flow calculation mode, so that the calculated result reduces errors of the power flow theory and the actual power flow theory of the flexibly-interconnected three-phase four-wire system power distribution network, and the precision of the power flow calculation result is improved. The technical problem that the calculation result error is large due to the fact that the three phases of a three-phase four-wire system power distribution network are unbalanced in the current power distribution network power flow calculation mode is solved.
Fig. 3 is a schematic diagram of an ac line of a flexibly-interconnected three-phase four-wire system power distribution network in the flexibly-interconnected three-phase four-wire system power distribution network power flow calculation method according to the embodiment of the application, and fig. 4 is a flowchart of a step of pushing back a power flow calculation mode in the flexibly-interconnected three-phase four-wire system power distribution network power flow calculation method according to the embodiment of the application.
As shown in fig. 3 and fig. 4, in one embodiment of the present application, the content of the push back power flow calculation method includes:
s01, acquiring electrical quantity parameters of m nodes of a first alternating current line or a second alternating current line in the flexible interconnection three-phase four-wire system power distribution network in real time, wherein the electrical quantity parameters comprise first current, voltage amplitude and impedance data; according to the voltage amplitude of each node and the first power data or the fourth power data, three-phase load current of the section line corresponding to each node is obtained;
s02, calculating according to the first current of the three phases of the end node to obtain the first neutral line current of the end node; according to the first current corresponding to each node and the three-phase load current of the line where the first current is positioned, adopting a forward superposition mode to calculate to obtain the three-phase current of the first line; according to the first neutral line current and the three-phase load current of the section line where each node corresponds to, calculating to obtain a second neutral line current of each node except the last node;
S03, according to impedance data of the electrical quantity parameters, voltage amplitude of a first node, first current of each node and second neutral line current, pushing back and calculating to obtain final node voltage;
s04, acquiring electrical quantity parameters of m nodes of a first alternating current circuit or a second alternating current circuit of the flexible interconnection three-phase four-wire system power distribution network again, performing iterative computation by adopting forward-push back power flow from the step S01 to the step S03 until a voltage difference value of two adjacent end node voltages meets a convergence condition, and correcting the node voltages obtained by the iterative computation to obtain voltage data of the power flow computation of the flexible interconnection three-phase four-wire system power distribution network.
In step S01 of the embodiment of the present application, calculating according to the voltage amplitude value and the first power data or the fourth power data of each node, to obtain a three-phase load current of a line in which each node corresponds to the segment includes:
according to the voltage amplitude of each node and the first power data or the fourth power data, a three-phase load current formula is adopted to calculate, and three-phase load current of a section of line corresponding to each node is obtained;
wherein, three-phase load current formula is:
wherein P is i The active power input to the section line corresponding to the ith node, qi is the reactive power input to the section line corresponding to the ith node, U i For the voltage amplitude of the ith node, I load，i And a, b and c are respectively three phases a, b and c of a three-phase four-wire system for the load current of the line of the corresponding section of the ith node.
In step S02 of the embodiment of the present application, the content of the forward push back power flow calculation method further includes:
calculating by adopting a neutral current calculation formula according to the first current of the three phases of the end node to obtain the first neutral line current of the end node; according to the first current corresponding to each node and the three-phase load current of the section line where the first current is positioned, adopting a forward superposition mode to calculate a first section line current calculation formula, and obtaining the three-phase current of the first section line; calculating by adopting a KCL law formula according to the first neutral line current and the three-phase load current of the section line where each node corresponds to, and obtaining a second neutral line current of each node except the last node;
wherein, the neutral current calculation formula is:
the first section line current calculation formula is:
KCL law formula is：
In the method, in the process of the application,respectively, a, b and c three phases are respectively first current after flowing through the m-th section line, +.>First neutral current for the end node, +.>The current of a, b and c three phases flowing through the first-stage line is respectively +.>Respectively, a, b and c three phases are respectively first current after flowing through the ith section line, +. > Load current of a, b and c three phases flowing through the ith section of line respectively, +.>A second neutral current that is the neutral of the ith node.
In step S03 of the embodiment of the present application, the content of the forward push back power flow calculation method further includes: according to impedance data of the electrical quantity parameters, voltage amplitude of the first node, three-phase load current of a section line where each node corresponds to and second neutral line current, adopting a voltage calculation formula to carry out backward calculation to obtain final node voltage;
the voltage calculation formula is:
in the method, in the process of the application,respectively, a, b and c three phases are respectively first current after flowing through the ith section line, +.>Second neutral current, which is the neutral line of the ith node,/>Impedance data on the i-th section of the three phases a, b and c respectively, < >>Impedance data for neutral line of ith node, < +.> Voltage drop at the ith node for the three phases a, b, c and neutral line n, respectively,/->Terminal voltages of three phases a, b, c and neutral line n, respectively, +.>The voltage amplitudes of the three phases a, b and c and the n first nodes of the neutral line are respectively.
The method for calculating the power flow of the flexibly interconnected three-phase four-wire system power distribution network sequentially returns current to the tail end of the line through a voltage calculation formula, and can calculate and obtain the end node voltage of the three-phase and neutral lines. The power flow calculation method of the flexibly-interconnected three-phase four-wire system power distribution network completely executes one-time forward push back power flow calculation through steps S01 to S03.
In step S04 of the embodiment of the present application, electrical parameters of m nodes of the first ac line or the second ac line of the flexible interconnected three-phase four-wire system power distribution network are obtained again, and then iterative computation is performed according to the contents of steps S01 to S03 until a voltage difference value of two adjacent end node voltages is obtained to satisfy a convergence condition, and then the computation of the power flow of the first ac line or the second ac line of the flexible interconnected three-phase four-wire system power distribution network is ended. Wherein, the convergence condition is:
in the method, in the process of the application,for the last node voltage calculated in the kth iteration in the tide calculation process, epsilon is a difference threshold, the difference threshold can be set according to requirements, and specific numerical values of the difference threshold are not limited.
It should be noted that, the last node voltage of the kth iterative computation includes four voltages of a, b, c three phases and a neutral line, and the convergence condition means that the iterative computation is completed only when the four voltages all meet the condition.
In step S04 of the embodiment of the present application, correcting the voltage of each node obtained by iterative calculation to obtain voltage data of the power flow calculation of the flexible interconnection three-phase four-wire system power distribution network includes: correcting the voltage of each node obtained by iterative calculation by adopting a correction formula to obtain voltage data of the power flow calculation of the flexible interconnection three-phase four-wire system power distribution network; the correction formula is:
In the method, in the process of the application,the voltage amplitudes of the three phases a, b, c and the neutral line n at the ith node,and calculating three-phase voltage data for the power flow of the flexible interconnection three-phase four-wire system power distribution network.
Fig. 5 is a schematic topology diagram of a flexibly-interconnected three-phase four-wire system power distribution network in the flexibly-interconnected three-phase four-wire system power distribution network power flow calculation method according to an embodiment of the present application, and fig. 6 is a graph of an ac line voltage peak in the flexibly-interconnected three-phase four-wire system power distribution network power flow calculation method according to an embodiment of the present application. In fig. 6, the first graph indicates a voltage peak graph when the ac voltage is most severe as the upper limit, the second graph indicates a voltage peak graph when the ac voltage is most severe as the lower limit, and the third graph indicates a voltage peak graph of the dc voltage.
In the embodiment of the application, according to the power flow calculation method of the flexible interconnected three-phase four-wire system power distribution network, two alternating current lines are connected through an inverter as shown in fig. 5, distributed photovoltaic access is arranged in part of nodes of the alternating current lines, the rated voltage of the lines is 380V, specific load parameters are shown in tables 1 and 2, and the obtained power flow calculation result is shown in fig. 6.
Table 1 shows load data for 21 node distribution network
Table 2 shows load data for 14 node power distribution network
Embodiment two:
fig. 7 is a frame flow chart of a power flow calculation device of a flexible-interconnection three-phase four-wire system power distribution network according to an embodiment of the application.
As shown in fig. 7, the embodiment of the application provides a power flow calculation device of a flexibly-interconnected three-phase four-wire system power distribution network, which comprises a first power flow calculation module 10, a power calculation module 20 and a second power flow calculation module 30;
the first power flow calculation module 10 is configured to obtain first power data for controlling operation of an inverter in the three-phase four-wire system power distribution network by using P-Q, and calculate a first ac line of the flexible interconnected three-phase four-wire system power distribution network by using a forward push back substitution power flow calculation mode according to the first power data, so as to obtain first power flow data;
the power calculation module 20 is configured to obtain second power data output by the first ac line, loss power of the converter, and third power data of the converter, and calculate according to the second power data, the third power data, and the loss power, to obtain fourth power data;
and the second power flow calculation module 30 is configured to calculate, according to the fourth power data, a second ac line of the flexible interconnected three-phase four-wire system power distribution network tide by adopting a forward push back substitution power flow calculation mode, so as to obtain second power flow data.
In the embodiment of the present application, the first power flow calculation module 10 and the second power flow calculation module 30 each include a first calculation sub-module, a second calculation sub-module, a third calculation sub-module and a fourth calculation sub-module;
the first calculation sub-module is used for acquiring electrical quantity parameters of m nodes of a first alternating current line or a second alternating current line in the flexible interconnection three-phase four-wire system power distribution network in real time, wherein the electrical quantity parameters comprise first current, voltage amplitude and impedance data; according to the voltage amplitude of each node and the first power data or the fourth power data, three-phase load current of the section line corresponding to each node is obtained;
the second calculation sub-module is used for calculating according to the first current of the three phases of the end node to obtain the first neutral line current of the end node; according to the first current corresponding to each node and the three-phase load current of the line where the first current is positioned, adopting a forward superposition mode to calculate to obtain the three-phase current of the first line; according to the first neutral line current and the three-phase load current of the section line where each node corresponds to, calculating to obtain a second neutral line current of each node except the last node;
the third calculation sub-module is used for calculating backward according to the impedance data of the electrical quantity parameters, the voltage amplitude of the first node, the first current of each node and the second neutral line current to obtain the voltage of the last node;
And the fourth calculation sub-module is used for re-acquiring the electrical quantity parameters of m nodes of the first alternating current circuit or the second alternating current circuit of the flexible interconnection three-phase four-wire system power distribution network, performing iterative calculation by adopting the forward push back power flow of the first calculation sub-module, the second calculation sub-module and the third calculation sub-module until the voltage difference value of the two adjacent end node voltages meets the convergence condition, and correcting the voltage of each node obtained by iterative calculation to obtain the voltage data of the power flow calculation of the flexible interconnection three-phase four-wire system power distribution network.
It should be noted that, the content of the module in the flexibly interconnected three-phase four-wire system power distribution network power flow calculation device corresponds to the content of the steps in the method in the embodiment, and the content of the steps in the method in the embodiment is described in the embodiment one, and the description of the content of the module in the embodiment two is not repeated in this embodiment.
Embodiment III:
the embodiment of the application provides terminal equipment, which comprises a processor and a memory;
a memory for storing program code and transmitting the program code to the processor;
and the processor is used for executing the flexible interconnected three-phase four-wire system power distribution network power flow calculation method according to the instructions in the program codes.
It should be noted that the processor is configured to execute the steps in the embodiment of the power flow calculation method for a flexibly interconnected three-phase four-wire system power distribution network according to the instructions in the program code. In the alternative, the processor, when executing the computer program, performs the functions of the modules/units in the system/apparatus embodiments described above.
For example, a computer program may be split into one or more modules/units, which are stored in a memory and executed by a processor to perform the present application. One or more of the modules/units may be a series of computer program instruction segments capable of performing specific functions for describing the execution of the computer program in the terminal device.
The terminal device may be a computing device such as a desktop computer, a notebook computer, a palm computer, a cloud server, etc. The terminal device may include, but is not limited to, a processor, a memory. It will be appreciated by those skilled in the art that the terminal device is not limited and may include more or less components than those illustrated, or may be combined with certain components, or different components, e.g., the terminal device may also include input and output devices, network access devices, buses, etc.
The processor may be a central processing unit (Central Processing Unit, CPU), other general purpose processor, digital signal processor (Digital Signal Processor, DSP), application specific integrated circuit (Application Specific Integrated Circuit, ASIC), off-the-shelf Programmable gate array (FPGA) or other Programmable logic device, discrete gate or transistor logic device, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory may be an internal storage unit of the terminal device, such as a hard disk or a memory of the terminal device. The memory may also be an external storage device of the terminal device, such as a plug-in hard disk provided on the terminal device, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), or the like. Further, the memory may also include both an internal storage unit of the terminal device and an external storage device. The memory is used for storing computer programs and other programs and data required by the terminal device. The memory may also be used to temporarily store data that has been output or is to be output.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other forms.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in part or all of the technical solution or in part in the form of a software product stored in a storage medium, including instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (10)

1. A power flow calculation method of a flexible interconnected three-phase four-wire system power distribution network is characterized by comprising the following steps:
acquiring first power data of converter operation in a three-phase four-wire system power distribution network controlled by P-Q, and calculating a first alternating current circuit of a flexible interconnection three-phase four-wire system power distribution network in a forward push back substitution power flow calculation mode according to the first power data to obtain first power flow data;
acquiring second power data output by the first alternating current line, loss power of the converter and third power data of the converter, and calculating according to the second power data, the third power data and the loss power to obtain fourth power data;
And calculating a second alternating current line of the flexible interconnection three-phase four-wire system power distribution network tide according to the fourth power data in a forward push back substitution tide calculation mode to obtain second tide data.
2. The method for calculating the power flow of the flexibly interconnected three-phase four-wire system power distribution network according to claim 1, wherein the content of the forward push back power flow calculation mode comprises the following steps:
s01, acquiring electrical quantity parameters of m nodes of a first alternating current line or a second alternating current line in a flexible interconnection three-phase four-wire system power distribution network in real time, wherein the electrical quantity parameters comprise first current, voltage amplitude and impedance data; according to the voltage amplitude value of each node and the first power data or the fourth power data, three-phase load current of a section line corresponding to each node is obtained;
s02, calculating according to the first current of the three phases of the end node to obtain the first neutral line current of the end node; according to the first current corresponding to each node and the three-phase load current of the line where the first current is positioned, adopting a forward superposition mode to calculate to obtain the three-phase current of the first line; according to the first neutral line current and the three-phase load current of the section line where each node corresponds to, calculating to obtain a second neutral line current of each node except the last node;
S03, according to the impedance data of the electrical quantity parameters, the voltage amplitude of the first node, the first current and the second neutral line current of each node, pushing back and calculating to obtain the voltage of the last node;
s04, acquiring electrical quantity parameters of m nodes of a first alternating current circuit or a second alternating current circuit of the flexible interconnection three-phase four-wire system power distribution network again, performing iterative computation by adopting forward-push back power flow from the step S01 to the step S03 until a voltage difference value of two adjacent end node voltages meets a convergence condition, and correcting the node voltages obtained by iterative computation to obtain voltage data of the power flow computation of the flexible interconnection three-phase four-wire system power distribution network.
3. The method for calculating the power flow of the flexibly interconnected three-phase four-wire system power distribution network according to claim 2, wherein calculating the three-phase load current of the section line corresponding to each node according to the voltage amplitude of each node and the first power data or the fourth power data comprises:
according to the voltage amplitude of each node and the first power data or the fourth power data, a three-phase load current formula is adopted to calculate, so that three-phase load currents of a section of line corresponding to each node are obtained;
Wherein, the three-phase load current formula is:
wherein P is i The active power input to the section line corresponding to the ith node, qi is the reactive power input to the section line corresponding to the ith node, U i For the voltage amplitude of the ith node, I load，i For the load current of the line of the section corresponding to the ith node, a, b and c are respectivelyThree phases a, b and c are four-wire system.
4. The method for calculating the power flow of the flexibly interconnected three-phase four-wire system power distribution network according to claim 2, wherein the content of the forward push back power flow calculation mode further comprises:
calculating by adopting a neutral current calculation formula according to the first current of the three phases of the end node to obtain the first neutral line current of the end node;
according to the first current corresponding to each node and the three-phase load current of the section line where the first current is positioned, adopting a forward superposition mode to calculate a first section line current calculation formula, and obtaining the three-phase current of the first section line;
calculating by adopting a KCL law formula according to the first neutral line current and the three-phase load current of the section line where each node corresponds to, and obtaining a second neutral line current of each node except the last node;
wherein, the neutral current calculation formula is:
the first section line current calculation formula is as follows:
The formula of KCL law is as follows:
in the method, in the process of the invention,respectively, a, b and c three phases are respectively first current after flowing through the m-th section line, +.>As the end nodeFirst neutral line current +.>The current of a, b and c three phases flowing through the first-stage line is respectively +.>Respectively, a, b and c three phases are respectively first current after flowing through the ith section line, +.> Load current of a, b and c three phases flowing through the ith section of line respectively, +.>A second neutral current that is the neutral of the ith node.
5. The method for calculating the power flow of the flexibly interconnected three-phase four-wire system power distribution network according to claim 2, wherein the content of the forward push back power flow calculation mode further comprises:
according to the impedance data of the electrical quantity parameters, the voltage amplitude of the first node, the three-phase load current of the section line corresponding to each node and the second neutral line current, a voltage calculation formula is adopted to carry out backward calculation, and the final node voltage is obtained;
the voltage calculation formula is as follows:
in the method, in the process of the invention,respectively, a, b and c three phases are respectively first current after flowing through the ith section line, +.>Second neutral current, which is the neutral line of the ith node,/>Impedance data on the i-th section of the three phases a, b and c respectively, < >>Impedance data for neutral line of ith node, < +. > Voltage drop at the ith node for the three phases a, b, c and neutral line n, respectively,/->The terminal voltages of the three phases a, b, c and the neutral line n respectively,the voltage amplitudes of the three phases a, b and c and the n first nodes of the neutral line are respectively.
6. The method for calculating the power flow of the flexibly interconnected three-phase four-wire system power distribution network according to claim 2, wherein correcting the voltage of each node obtained by the iterative calculation to obtain the voltage data of the flexibly interconnected three-phase four-wire system power distribution network comprises: correcting the voltage of each node obtained by iterative calculation by adopting a correction formula to obtain voltage data of the power flow calculation of the flexible interconnection three-phase four-wire system power distribution network; the correction formula is:
in the method, in the process of the invention,the voltage amplitudes of the three phases a, b, c and the neutral line n at the ith node,and calculating three-phase voltage data for the power flow of the flexible interconnection three-phase four-wire system power distribution network.
7. The method of power flow calculation for a flexibly interconnected three-phase four-wire system power distribution network of claim 1, wherein calculating fourth power data from the second power data, the third power data, and the loss power comprises:
calculating by adopting a first power calculation formula according to the third power data and the loss data to obtain fifth power data of the power distribution network injected by the converter controlled by the P-Q;
Calculating by adopting a second power calculation formula according to the fifth power data and the second power data to obtain alternating current active data and alternating current reactive data of the fourth power data;
calculating by adopting a third power calculation formula according to the third power data, the loss power and the second power data to obtain direct current active power of the fourth power data;
the first power calculation formula is as follows:
the second power calculation formula is:
the third power calculation formula is:
in the method, in the process of the invention,respectively is an alternating current line of a power distribution network>Phase i node connects active power and reactive power of the converter, < >>Ac line for distribution network>Phase i node connects the lost power of the converter, < >>Active alternating current data and reactive alternating current data which are respectively fifth power data; />First ac line respectively->Active power and reactive power output by the ith node, namely second power data; />Respectively the second alternating current linesActive power and reactive power of the i-th node of the phase, namely alternating current power of fourth power data; />To inject active power of an inverter at an ith node of a power distribution network, P i 0+ For the active power of the i-th node in the second power data,/and/or >And the direct current power of the ith node in the fourth power data.
8. The utility model provides a flexible interconnected three-phase four-wire system distribution network power flow calculation device which is characterized by comprising a first power flow calculation module, a power calculation module and a second power flow calculation module;
the first power flow calculation module is used for obtaining first power data of the current converter operation in the three-phase four-wire system power distribution network controlled by adopting P-Q, and calculating a first alternating current line of the flexible interconnection three-phase four-wire system power distribution network in a forward push back substitution power flow calculation mode according to the first power data to obtain first power flow data;
the power calculation module is used for obtaining second power data output by the first alternating current circuit, loss power of the converter and third power data of the converter, and calculating according to the second power data, the third power data and the loss power to obtain fourth power data;
and the second power flow calculation module is used for calculating a second alternating current line of the flexible interconnection three-phase four-wire system power distribution network tide in a forward push back substitution power flow calculation mode according to the fourth power data to obtain second power flow data.
9. The flexibly interconnected three-phase four-wire system power distribution network power flow computing device of claim 8, wherein the first power flow computing module and the second power flow computing module each comprise a first computing sub-module, a second computing sub-module, a third computing sub-module, and a fourth computing sub-module;
The first calculation submodule is used for acquiring electrical quantity parameters of m nodes of a first alternating current line or a second alternating current line in the flexible interconnection three-phase four-wire system power distribution network in real time, wherein the electrical quantity parameters comprise first current, voltage amplitude and impedance data; according to the voltage amplitude value of each node and the first power data or the fourth power data, three-phase load current of a section line corresponding to each node is obtained;
the second calculation sub-module is used for calculating according to the first current of the three phases of the end node to obtain the first neutral line current of the end node; according to the first current corresponding to each node and the three-phase load current of the line where the first current is positioned, adopting a forward superposition mode to calculate to obtain the three-phase current of the first line; according to the first neutral line current and the three-phase load current of the section line where each node corresponds to, calculating to obtain a second neutral line current of each node except the last node;
the third calculation sub-module is used for performing backward pushing calculation according to the impedance data of the electrical quantity parameters, the voltage amplitude of the first node, the first current of each node and the second neutral line current to obtain the voltage of the last node;
The fourth calculation sub-module is configured to re-acquire electrical quantity parameters of m nodes of the first ac line or the second ac line of the flexible interconnected three-phase four-wire system power distribution network, and perform iterative calculation by adopting the forward push back substitution power flow of the first calculation sub-module, the second calculation sub-module and the third calculation sub-module until a voltage difference value of two adjacent terminal node voltages is obtained and meets a convergence condition, and correct the voltage of each node obtained by iterative calculation to obtain voltage data of the power flow calculation of the flexible interconnected three-phase four-wire system power distribution network.
10. A terminal device comprising a processor and a memory;
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to execute the flexibly interconnected three-phase four-wire system power distribution network power flow calculation method according to the instructions in the program code.
CN202310642154.XA 2023-05-31 2023-05-31 Flexible interconnected three-phase four-wire system distribution network power flow calculation method, device and equipment Pending CN116760037A (en)

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