WO2016006091A1 - Dispositif et procédé d'analyse de système d'alimentation - Google Patents

Dispositif et procédé d'analyse de système d'alimentation Download PDF

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Publication number
WO2016006091A1
WO2016006091A1 PCT/JP2014/068530 JP2014068530W WO2016006091A1 WO 2016006091 A1 WO2016006091 A1 WO 2016006091A1 JP 2014068530 W JP2014068530 W JP 2014068530W WO 2016006091 A1 WO2016006091 A1 WO 2016006091A1
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Prior art keywords
power system
system analysis
nodes
analysis device
power
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PCT/JP2014/068530
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English (en)
Japanese (ja)
Inventor
犬塚　達基
俊之 三宅
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株式会社日立製作所
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Priority to PCT/JP2014/068530 priority Critical patent/WO2016006091A1/fr
Publication of WO2016006091A1 publication Critical patent/WO2016006091A1/fr

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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

Definitions

  • the present invention relates to a power system analysis apparatus and method for analyzing a power system.
  • the power system is operated with a balance between supply and demand, while various devices that generate and consume power perform their own operations.
  • many power plants that generate electric power have been centrally installed and operated by electric power companies.
  • distributed power sources such as solar power generation and wind power generation have begun to spread in order to utilize natural energy.
  • the power generation amount of these distributed power sources varies depending on weather conditions. For example, the amount of solar radiation, wind direction, and wind speed cause changes in power generation.
  • a large-capacity storage battery may be mounted on an electric vehicle or the like, and may be connected to the grid while changing the connection point, the connection time, the charge / discharge capacity, and the like.
  • the power system is composed of a combination of L (inductance), C (capacitance), R (resistance), etc., and the state values of the power system are V (voltage), I (current), P (active power), Q (invalid) Power) and ⁇ (phase).
  • L inductance
  • C capacitor
  • R resistance
  • ⁇ phase
  • Simulators that perform power flow calculations for system analysis using equations related to such power systems are widely used. It is used to calculate the power flowing through the line by specifying state values such as input / output power of the load.
  • Patent Document 1 as a method for calculating a mathematical model of a power system by parallel calculation. The behavior of voltage and current is calculated by setting the time step for calculation and repeatedly calculating.
  • the power equation described above is a nonlinear simultaneous equation
  • a numerical calculation method such as the Newton-Raphson method is used.
  • a matrix-type nonlinear power equation is prepared in advance. Therefore, if there is a change in the system configuration, it is necessary to rewrite the power equation, which is a mathematical model, and the power flow calculation cannot be continued in response to another structure (mesh structure, tree structure, etc.) or dynamic reconfiguration of the power system.
  • Patent Document 1 calculates a voltage / current waveform for the purpose of power system surge analysis, and is not suitable for calculating power flow.
  • the present invention provides a power system analysis device that analyzes a power system configured based on a plurality of nodes and a branch that connects the nodes, and includes power on a load side connected to the nodes.
  • Means for calculating a load power indicative of a complex voltage gradient of the branch based on the load power, and a complex voltage of an adjacent node connected to the node via the branch based on the complex voltage gradient And means for calculating the correction amount for nodes within a predetermined range in the power system.
  • power flow calculation can be started without preprocessing such as making a mathematical model in advance. , Tree structure, etc.) or dynamic flow reconstruction can be continued.
  • Off-line may be used for the purpose of evaluating and analyzing the characteristics of the system configuration in advance.
  • the purpose is to calculate a control command to a control device in the power system, an online form is obtained.
  • the present invention described below can be applied to both online and offline.
  • Fig. 1 schematically shows the configuration of the power system.
  • the node 101 is a system component such as a transformer, reactance, capacitance, etc., or a load installed by a consumer, a distributed power source using renewable energy.
  • the branch 102 is a line connecting the nodes 101 and has characteristics such as line type and line impedance.
  • the power system can be described as a relationship in which the node 101 and the branch 102 are connected. For example, a method for describing the connection relationship between the node 101 and the branch 102 with text data is easy to create and highly versatile, but preprocessing for replacing the text data with a mathematical model is essential.
  • the present invention arranges the node 101 and the branch 102 in a diagrammatic manner.
  • the mathematical model will be called a graphical model.
  • the graphical meaning is to describe a picture on a two-dimensional plane while maintaining the adjacent relationship between the node 101 and the branch 102. In other words, this corresponds to writing the elements that are adjacent to each other on the power system so that they are adjacent to each other in a two-dimensional array.
  • this two-dimensional array has a data structure prepared in a programming language, it is possible to refer to adjacent elements by changing the array index by one.
  • the two-dimensional array is a memory device, the elements in the adjacent relationship can be referred to by regular change of the memory address.
  • the node 101 is represented by a symbol ⁇
  • the branch 102 is represented by a line connecting ⁇
  • information on the node 101 and the branch 102 can be written as attached information.
  • the node 101 and the branch 102 may be represented by the same symbol ⁇ . Or you may handle the intersection of a grid-like vertical and horizontal line as an element. Since the node 101 and the branch 102 have different functions, they may be distinguished from each other.
  • Such a schematic model enables interactive data input with the operator.
  • the above-described graphically represented screen is presented to the operator, and the operator can write the power system while viewing the screen, or can correct the data input in advance.
  • the written screen can be used for a calculation procedure to be described later by treating it as a two-dimensional schematic model. Since the calculation results are made of the same two-dimensional array, the calculation results can be displayed on the screen superimposed on the input data.
  • a node of interest is N 3
  • an adjacent node is N 4
  • a branch connecting the two is Line 34 .
  • the voltage of each node is V 3 and V 4
  • the impedance of the branch is Z 34
  • the flowing current is I 34 .
  • the node N 4 is connected to a load and consumes power S. In the initial state, all node voltages are Vs, and the current flowing through the branch is zero. By initializing the impedance of the branch as infinite, it does not contribute to the calculation of the power flow when there is no allocation of power system elements.
  • These variables are expressed as complex numbers including phase. In the following description, the complex number format may not be specified for the sake of simplicity.
  • FIG. 5 shows a flowchart. Since the power S is consumed at the node N 4 , the current L 4 flowing through the load is
  • V 3 V 4 -I 34 ⁇ Z 34 You can correct it. Or it may share the magnitude of the voltage correction calculated in the node N 3 and the node N 4 adjacent.
  • this correction value is obtained only from the relationship between the node N 3 and the node N 4 , but in reality, other connected nodes must be considered. Further, when the correction value is directly used, the solution may oscillate or diverge. Therefore, a correction coefficient K is prepared so that the correction is gradually performed, and the following is set as a correction value.
  • V 3 (V 4 -I 34 ⁇ Z 34 ) ⁇ K
  • the correction coefficient K is used as a numerical value of 0 ⁇ K ⁇ 1 in the repeated calculation described below.
  • the above basic calculation is obtained from the relationship between two adjacent nodes.
  • This procedure may be extended to the relationship between adjacent nodes as shown in FIG.
  • the relationship between the complex voltage and the complex current is derived from the relationship between the node N of interest and the node adjacent to the node N.
  • the correction coefficient K is used as a numerical value of 0 ⁇ K ⁇ 1 to gradually reflect the correction value in the repeated calculation described below.
  • the correction value is calculated by scanning all the combinations of nodes and branches constituting the system.
  • FIG. 8 shows an example of the order in which the calculation proceeds.
  • the scanning order may be such that the upper left of the graphical model is the starting point and the lower right is the ending point, such as the scanning order of electron beams of a cathode ray tube.
  • the correction amount gradually decreases and approaches a stable state.
  • the situation gradually approaching the stable state is adjusted by the correction coefficient K described above.
  • a method for setting the correction coefficient K will be described later.
  • the power flow calculation procedure of the present invention does not need to prepare a mathematical model of the power system in advance. Since iterative calculations are performed based on the schematic model, if there is a change in the system configuration over the course of the iterative calculation, there is a feature that enables dynamic reconfiguration that can be reflected in the calculation simply by changing the schematic model . There is no need to do any pre-processing before starting the tidal calculation.
  • the calculation can be advanced by scanning the two-dimensional array prepared on the memory. This two-dimensional array can have the same data structure for the purpose of writing the configuration of the power system and the purpose of writing the result.
  • the procedure for obtaining a stable power solution according to the present invention by repetitive calculation reproduces the state in which power gradually diffuses, similar to heat diffusion.
  • the temperature is a scalar value
  • the power system is represented by a complex number. Elements constituting the power system include supply and consumption of power.
  • the present invention interprets the flow of power to reach a stable solution through repeated trial and error. In the process of trial and error leading to a stable solution, the correction amount per time may be an appropriate minute amount that does not diverge.
  • Correction coefficient setting method adaptive setting The correction coefficient K is prepared and the correction amount is calculated.
  • This correction coefficient is set to 0 ⁇ K ⁇ 1 as described above.
  • the size can be variably set while observing the above restrictions. These tendencies may vary depending on the structure of the system.
  • the correction coefficient the same numerical value may be used for the entire system, but it may be a different correction coefficient depending on the type and area of the system. Further, in combination with means for observing the degree of convergence, the numerical values may be switched in the process of repeated calculation.
  • a numerical value is set by preparing means for determining and determining determination criteria such as stable convergence and quick convergence.
  • a numerical value for characteristic confirmation can be set, and the numerical value can be variably set based on the result.
  • the correction coefficient may be set to a different value depending on the part or region of the system configuration.
  • the device may be configured such that the operator sets this correction factor via an interface.
  • an interface that allows the operator to explicitly adjust the correction coefficient can be prepared. This purpose is useful, for example, to help the operator learn the calculation algorithm.
  • the impedance load is a device whose load power is determined based on Ohm's law, and corresponds to, for example, a lamp.
  • the constant power load is a device that uses a semiconductor circuit to control the load power to be constant. For example, there is a corresponding device such as an air conditioner.
  • the load for driving the semiconductor circuit by program control can have power characteristics that cannot be approximated by the simple mathematical model as described above. It is easy to reproduce the operation of the program control in the repeated calculation. Both loads consider the characteristics of active power and reactive power, that is, power factor.
  • the node voltage is corrected in the process of repetitive calculation, so that the current flowing through the load changes due to voltage fluctuation.
  • the recalculation of these load powers is executed in the repeated calculation.
  • Equipment that supplies power can be regarded as a load having a minus sign. Since the storage battery performs both consumption and supply, it can be regarded as a load that can be switched. Since both are DC power supplies, conversion by an inverter is indispensable for connecting to an AC system.
  • PCS Power Conditioning System
  • PCS Power Conditioning System
  • control functions such as control of power factor (active power and reactive power) and suppression of power supply in addition to the inverter function. If these operation contents are known, it is easy to incorporate them into the power flow calculation procedure of the present invention.
  • the voltage used in the power system is called a voltage class.
  • a high voltage is used to reduce power loss due to the line, and in the power distribution system, a low voltage suitable for supplying to general consumers is used.
  • Transformers are used to convert these voltages.
  • the transformer is a device that performs voltage conversion using a ratio of the number of windings on the primary side and the secondary side.
  • the voltage conversion function of the transformer is assigned as a function of a node connected to the branch on the primary side and the secondary side.
  • the primary side and the secondary side are discriminated and the winding ratio between the primary side and the secondary side is set in advance.
  • the complex voltage and complex current of this node itself are set as the primary side, for example.
  • the complex voltage and complex current converted by the winding ratio are allocated to the branch connected to the secondary side.
  • the node having the function of the transformer can see the converted complex voltage and complex current on the primary side and the secondary side, respectively.
  • a switching converter is configured by combining an inductance, a capacitance, a diode, and the like with a semiconductor switch that performs high-speed on / off.
  • a switching converter is configured by combining an inductance, a capacitance, a diode, and the like with a semiconductor switch that performs high-speed on / off.
  • Control equipment for the purpose of voltage stabilization is used in the power system.
  • control content is transmitted from a centralized management means. The operation of these control devices is simulated and incorporated into the power flow calculation.
  • SVR is a kind of transformer, it can be handled in the same way as the above-mentioned transformer. However, the turns ratio can be changed by tap switching. An input means for the tap switching signal is prepared. Voltage control devices such as SVCs and storage batteries can be handled in the same way as loads connected to nodes. Both can be incorporated into the tidal current calculation by deciding the operation of the aircraft while observing the voltage and current in the process of repeated calculations.
  • Constraint function In the operation of the power system, control is performed to achieve a desired state.
  • One of them is voltage, and if it is a distribution system, it is required to be within the range of 101 ⁇ 6V. Similar voltage ranges are determined for other voltage classes.
  • the present invention in order to realize such a voltage range constraint, provides a voltage constraint function in the process of calculating the voltage of the node and branch.
  • the correction amount is multiplied by a constraint function so that the correction amount is not directed to the outside of the voltage range.
  • FIG. 9 shows an example of the constraint function. If the shape has a size of 0 around the voltage range, this constraint function works so as not to create a correction amount that goes outside the voltage range. Or it can be rephrased as an induction function because it works to induce voltage.
  • the above constraint function or induction function can be determined in advance, and can be arbitrarily changed while observing the state of the system. Since the power flow calculation means stores the state value of the entire target system in a variable or some kind of memory, it goes without saying that the state at an arbitrary location can be observed. Furthermore, it is possible to prepare some evaluation function created by combining variables, and to switch the above-described constraint function or induction function while looking at the result of the evaluation function.
  • the target value is a state value such as voltage, current, or power, or a tap setting value of a device including a tap switching unit.
  • This procedure can be used to calculate a control signal for voltage stabilization of the power system, such as setting a higher voltage or setting a lower voltage.
  • Three-phase unbalanced power systems are often configured as a set of three phases shifted in AC phase.
  • One method applied to the polyphase is to assign one line to one phase, and the polyphase is described by combining single-phase lines.
  • the other is to assign polyphase properties to one line and incorporate the polyphase calculation into a single line calculation procedure.
  • the present invention can realize any configuration.
  • GUI In the present invention, nodes and branches are arranged in a diagrammatic manner to advance calculation of power flow.
  • a graphical user interface can be used as a diagrammatic arrangement mechanism. An example is shown below.
  • a screen on which array elements as shown in FIG. 10 are arranged is prepared.
  • the element ⁇ is distinguished by a node and a branch, and both are arranged alternately.
  • This figure shows the progress of the repeated calculation described by the mouse operation on the display screen 104 of the PC 103.
  • the nodes and branches are actually selected with a mouse, pen, or keyboard.
  • the selected array element is assigned a device type, function, performance, etc. in configuring the power system. When it is not assigned, only selectable frameworks are shown or initial values are provided so as not to contribute to the system configuration. In order to improve the visual design and improve the efficiency of the operator, elements that do not contribute may be written.
  • display can be performed using the above-described array element format, and state values relating to the power system can be displayed. It is possible to confirm the state of convergence with the so-called “jiwajiwa”. However, this does not always indicate a transient response. Thus, by displaying the power system input screen and the screen for displaying the result of power flow calculation in an overlapping manner, the relationship between the cause and the result can be displayed in an easily understandable manner.
  • the present invention can be used as a simulator for analyzing a power system.
  • the present invention can also be used as a control device that generates a control signal for controlling an electric power system.
  • various sensor data related to the power system can be collected and used in a calculation procedure.
  • the control device can be applied to any configuration called a centralized type or a distributed type. Compare the collected sensor data with the simulator output according to the present invention, and correct the characteristics of the simulator of the present invention so as to reduce the error between the two. It can be used as a so-called observer.
  • the processor format is not limited, but a general-purpose processor called CPU (Central Processing Unit), a many-core processor called GPU (Graphic Processing Unit, General Purpose Unit, etc.), etc. are used.
  • CPU Central Processing Unit
  • GPU Graphic Processing Unit, General Purpose Unit, etc.
  • FIG. 11 in general, there are many configurations in which the CPU 105 performs overall system processing such as OS management, and the GPU 106 is installed as an additional device of the system.
  • the additional device equipped with the GPU 106 can be obtained as a general-purpose graphics board 109 or a dedicated parallel computing board.
  • a two-dimensional array memory 107 for handling image data is provided.
  • the nodes and branches of the power system are allocated to a two-dimensional array memory, and the device characteristics are written in the memory 107. Nodes and branches may be assigned as different variables in the same memory area. In any case, the operation is regularly executed by storing the adjacent nodes and the characteristics of the branch connecting them in a memory with regular addresses.
  • the GPU 106 is characterized by including a plurality of arithmetic units, and the individual arithmetic units execute memory access and arithmetic operations in parallel, thereby realizing high-speed overall signal processing.
  • the characteristic data of the power system is graphically arranged in the memory 107. It becomes easy to assign a plurality of arithmetic units included in the GPU 106 to elements constituting the power system. A plurality of arithmetic units can perform parallel processing, which is effective in speeding up repeated calculations.
  • the program for instructing the calculation procedure is described in the same manner as the image processing that handles pixel data, and the effect of parallel execution is obtained.
  • the graphics board 109 provided with the GPU 106 can execute parallel computation and screen display simultaneously.
  • the memory 107 that stores the elements and status of the system configuration may be used in common for both purposes.
  • Electric power can be replaced with other energy by unit conversion.
  • J Ws.
  • the energy flowing through the devices and branches arranged at the nodes may be replaced with heat.
  • a primary side and a secondary side having different units as in the transformer described above are prepared. The primary side and the secondary side are distinguished from each other, power is taken into the primary side, and the secondary side has a function of heat diffusion (or consumption). Both perform energy conversion according to the conversion equation described above.
  • the flow of electric power and heat can be calculated by performing energy conversion in the repeated calculation of the power flow calculation of the present invention.

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

Abstract

Si un changement se produit dans la configuration d'un système d'alimentation, il devient nécessaire de réécrire une équation de puissance qui est un modèle mathématique, et un calcul de flux de charge ne peut pas être poursuivi en réponse à d'autres structures de système d'alimentation (une structure maillée, une structure arborescente, ou autre) ou une reconfiguration dynamique. Par conséquent, la présente invention porte sur un dispositif d'analyse de système d'alimentation qui analyse un système d'alimentation configuré sur la base d'une pluralité de nœuds et de branches qui connectent les nœuds, ledit dispositif d'analyse de système d'alimentation étant caractérisé par la fourniture : d'un moyen pour calculer une puissance de charge qui représente la puissance sur un côté de charge qui est connecté aux nœuds ; dlun moyen pour calculer le gradient de tension complexe des branches sur la base de la puissance de charge ; d'un moyen pour calculer, sur la base du gradient de tension complexe, une quantité de correction pour la tension complexe d'un nœud adjacent qui est connecté aux nœuds par l'intermédiaire des branches ; d'un moyen pour calculer la quantité de correction pour des nœuds dans les limites d'une plage prédéterminée dans le système d'alimentation.
PCT/JP2014/068530 2014-07-11 2014-07-11 Dispositif et procédé d'analyse de système d'alimentation WO2016006091A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107633132A (zh) * 2017-09-18 2018-01-26 湖南大学 空间分布动态载荷的等效识别方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09205731A (ja) * 1996-01-24 1997-08-05 Tokyo Electric Power Co Inc:The 電力系統計算装置
JP2003235157A (ja) * 2002-02-05 2003-08-22 Mitsubishi Electric Corp 電力系統の行設備グループ作成方式および潮流計算方式
JP2005033848A (ja) * 2003-07-07 2005-02-03 Tm T & D Kk 電力系統の位相角差計算方法、電力系統の位相角計算方法、および電力系統解析装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09205731A (ja) * 1996-01-24 1997-08-05 Tokyo Electric Power Co Inc:The 電力系統計算装置
JP2003235157A (ja) * 2002-02-05 2003-08-22 Mitsubishi Electric Corp 電力系統の行設備グループ作成方式および潮流計算方式
JP2005033848A (ja) * 2003-07-07 2005-02-03 Tm T & D Kk 電力系統の位相角差計算方法、電力系統の位相角計算方法、および電力系統解析装置

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107633132A (zh) * 2017-09-18 2018-01-26 湖南大学 空间分布动态载荷的等效识别方法

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