CN116595699B - Interactive processing method and device for power quality of converter and power distribution network - Google Patents
Interactive processing method and device for power quality of converter and power distribution network Download PDFInfo
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Abstract
The invention provides a method and a device for interactively processing the electric energy quality of an inverter and a power distribution network, wherein the method comprises the following steps: acquiring basic parameters of a converter and basic parameters of a power distribution network, and determining a plurality of electric energy quality influence models according to the basic parameters of the converter and the basic parameters of the power distribution network; establishing an electric energy quality interaction model of the converter and the power distribution network by using the electric energy quality influence model; the power quality interaction model of the converter and the power distribution network is used for quantitatively analyzing and processing power quality interaction of the power distribution network comprising the converter. According to the invention, quantitative power quality interaction analysis is carried out on the low-voltage distribution network comprising the power electronic converter, the multi-index coupling relation of the power quality is fully represented, quantitative power quality interaction analysis is carried out on the low-voltage distribution network comprising the power electronic converter, the disclosure of the cause of the power quality problem in the distribution network and the contribution ratio of different causes to the final problem is facilitated, and directional guidance is provided for the power quality improvement engineering of the distribution network.
Description
Technical Field
The invention relates to the technical field of power distribution networks, in particular to a method and a device for interactive processing of power quality of a converter and a power distribution network.
Background
Along with the rapid development of smart power grids and the development and utilization of large-scale renewable energy sources, a large number of novel power electronic converters such as photovoltaic inverters, energy storage converters, electric automobile charging piles and the like are introduced into a power distribution network. The power system has obvious high permeability and high power electronization characteristics, and the power quality of the power grid is subverted compared with the past. The electric energy quality interaction mechanism model is a precondition of power grid optimization design, performance analysis and comprehensive evaluation.
However, the traditional power quality modeling method is carried out through numerical simulation or single-index analysis calculation, and has the problems that only qualitative analysis can not quantitatively analyze or the index is considered to be incomplete and the conclusion is on one side. And most modeling methods analyze the interaction relationship between the converter and the power distribution network, either take the converter as an ideal power supply to analyze the internal problems of the power distribution network in detail, or take the power distribution network equivalent as the ideal power supply to analyze the internal problems of the converter in an important way. This results in an inaccurate modeling of the power quality interaction mechanism, resulting in large errors in the final model application.
Disclosure of Invention
Aiming at the problems existing in the prior art, the main purpose of the embodiment of the invention is to provide a method and a device for processing the power quality interaction of a converter and a power distribution network, which realize quantitative power quality interaction analysis of a low-voltage power distribution network comprising a power electronic converter and provide directional guidance for power quality improvement engineering of the power distribution network.
In order to achieve the above objective, an embodiment of the present invention provides a method for interactively processing power quality of a converter and a power distribution network, where the method includes:
acquiring basic parameters of a converter and basic parameters of a power distribution network, and determining a plurality of electric energy quality influence models according to the basic parameters of the converter and the basic parameters of the power distribution network;
establishing an electric energy quality interaction model of the converter and the power distribution network by using the electric energy quality influence model; the power quality interaction model of the converter and the power distribution network is used for quantitatively analyzing and processing power quality interaction of the power distribution network comprising the converter.
Optionally, in an embodiment of the present invention, the basic parameters of the inverter include a photovoltaic cell maximum power point voltage standard value, a photovoltaic cell maximum power point current standard value, a photovoltaic cell light intensity standard value, an inverter dc bus capacitance value, an inverter dc bus voltage given value, an inverter closed loop transfer function, an inverter output impedance, an inverter dc voltage outer loop scaling factor, an inverter dc voltage outer loop integration factor, and a grid voltage nominal value.
Optionally, in an embodiment of the present invention, the basic parameters of the power distribution network include a topology structure of the power distribution network, a rated voltage class, a rated operating frequency, a line impedance between nodes, a capacity of the converter of each node, and a load capacity of each node.
Optionally, in an embodiment of the present invention, the power quality influence model includes a converter fine harmonic mathematical model, a power quality interaction mathematical model of the power distribution network, a three-phase unbalanced harmonic power fluctuation coupling model, a light intensity variation voltage deviation transient coupling model, and a power grid background harmonic converter harmonic coupling model.
The embodiment of the invention also provides a device for processing the interaction of the power quality of the converter and the power distribution network, which comprises the following steps:
the power quality module is used for acquiring basic parameters of the converter and basic parameters of the power distribution network and determining a plurality of power quality influence models according to the basic parameters of the converter and the basic parameters of the power distribution network;
the interaction analysis module is used for establishing an interaction model of the power quality of the converter and the power distribution network by using the power quality influence model; the power quality interaction model of the converter and the power distribution network is used for quantitatively analyzing and processing power quality interaction of the power distribution network comprising the converter.
Optionally, in an embodiment of the present invention, the basic parameters of the inverter include a photovoltaic cell maximum power point voltage standard value, a photovoltaic cell maximum power point current standard value, a photovoltaic cell light intensity standard value, an inverter dc bus capacitance value, an inverter dc bus voltage given value, an inverter closed loop transfer function, an inverter output impedance, an inverter dc voltage outer loop scaling factor, an inverter dc voltage outer loop integration factor, and a grid voltage nominal value.
Optionally, in an embodiment of the present invention, the basic parameters of the power distribution network include a topology structure of the power distribution network, a rated voltage class, a rated operating frequency, a line impedance between nodes, a capacity of the converter of each node, and a load capacity of each node.
Optionally, in an embodiment of the present invention, the power quality influence model includes a converter fine harmonic mathematical model, a power quality interaction mathematical model of the power distribution network, a three-phase unbalanced harmonic power fluctuation coupling model, a light intensity variation voltage deviation transient coupling model, and a power grid background harmonic converter harmonic coupling model.
The invention also provides an electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the above method when executing the program.
The present invention also provides a computer-readable storage medium storing a computer program for executing the above method by a computer.
The invention also provides a computer program product comprising computer programs/instructions which when executed by a processor implement the steps of the above method.
According to the invention, quantitative electric energy quality interaction analysis is carried out on the low-voltage distribution network comprising the power electronic converter, and an electric energy quality interaction model of the converter and the distribution network is established, so that the multi-index coupling relation of the electric energy quality is fully represented, quantitative electric energy quality interaction analysis is carried out on the low-voltage distribution network comprising the power electronic converter, the disclosure of the cause of the electric energy quality problem in the distribution network and the contribution ratio of different causes to the final problem is facilitated, and directional guidance is provided for the electric energy quality improvement engineering of the distribution network.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flowchart of a method for processing power quality interaction between an inverter and a power distribution network according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a typical inverter topology according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a typical power distribution network topology in an embodiment of the present invention;
FIG. 4 is a flow chart illustrating the construction of a power quality factor model in accordance with one embodiment of the present invention;
fig. 5 is a schematic diagram of a general model of a mechanism for interaction between a converter and power quality of a power distribution network according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of an interactive processing device for power quality of a converter and a power distribution network according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of an electronic device according to an embodiment of the invention.
Detailed Description
The embodiment of the invention provides a method and a device for interactively processing the power quality of a converter and a power distribution network.
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Fig. 1 is a flowchart of a method for processing power quality interaction between a converter and a power distribution network according to an embodiment of the present invention, where a main body of execution of the method for processing power quality interaction between a converter and a power distribution network provided by the embodiment of the present invention includes, but is not limited to, a computer. According to the invention, quantitative electric energy quality interaction analysis is carried out on the low-voltage distribution network comprising the power electronic converter, and an electric energy quality interaction model of the converter and the distribution network is established, so that the multi-index coupling relation of the electric energy quality is fully represented, quantitative electric energy quality interaction analysis is carried out on the low-voltage distribution network comprising the power electronic converter, the disclosure of the cause of the electric energy quality problem in the distribution network and the contribution ratio of different causes to the final problem is facilitated, and directional guidance is provided for the electric energy quality improvement engineering of the distribution network. The method shown in the figure comprises the following steps:
step S1, basic parameters of a converter and basic parameters of a power distribution network are obtained, and a plurality of electric energy quality influence models are determined according to the basic parameters of the converter and the basic parameters of the power distribution network;
s2, establishing an electric energy quality interaction model of the converter and the power distribution network by using an electric energy quality influence model; the power quality interaction model of the converter and the power distribution network is used for quantitatively analyzing and processing power quality interaction of the power distribution network comprising the converter.
As one embodiment of the invention, the basic parameters of the converter comprise a photovoltaic cell maximum power point voltage standard value, a photovoltaic cell maximum power point current standard value, a photovoltaic cell light intensity standard value, an inverter direct current bus capacitance value, an inverter direct current bus voltage given value, an inverter closed loop transfer function, an inverter output impedance, an inverter direct current voltage outer loop proportional coefficient, an inverter direct current voltage outer loop integral coefficient and a power grid voltage nominal value.
As one embodiment of the invention, the basic parameters of the power distribution network include the topology of the power network, rated voltage class, rated operating frequency, line impedance between nodes, capacity of the converter of each node and load capacity of each node.
The method comprises the steps of establishing a fine harmonic mathematical model of the current converter and a power quality interaction mathematical model of the power distribution network according to the operation mechanism of the current converter by utilizing the basic parameters of the current converter and the basic parameters of the power distribution network, establishing a three-phase unbalanced harmonic power fluctuation coupling model according to the influence mechanism of three-phase unbalance on the current converter, establishing a light intensity change voltage deviation transient coupling model according to the influence mechanism of light intensity change on the current converter, and establishing a power grid background harmonic current converter harmonic coupling model according to the influence mechanism of power grid background harmonic on the current converter.
As one embodiment of the invention, the power quality influence model comprises a converter fine harmonic mathematical model, a power quality interaction mathematical model of a power distribution network, a three-phase unbalanced harmonic power fluctuation coupling model, a light intensity variation voltage deviation transient coupling model and a power grid background harmonic converter harmonic coupling model.
The fine harmonic mathematical model of the converter quantitatively characterizes the voltage harmonic and current harmonic problem of the converter, which is caused by the modulation process of the power electronic switch, and the electric energy quality interaction mathematical model of the power distribution network quantitatively characterizes the voltage harmonic, current harmonic, three-phase imbalance, voltage deviation and voltage transient of the power distribution network and the interaction influence problem among the voltage harmonic, current harmonic, three-phase imbalance, voltage deviation and voltage transient of the converter.
Further, the three-phase unbalanced harmonic power fluctuation coupling model quantitatively characterizes the problems of converter voltage harmonic waves, current harmonic waves and voltage deviation caused by three-phase unbalance of the power distribution network voltage, and the light intensity change voltage deviation transient coupling model quantitatively characterizes the problems of converter node voltage deviation and voltage transient caused by the change of light intensity and converter power instructions. The power grid background harmonic converter harmonic coupling model quantitatively characterizes the problem of interaction influence between voltage and current harmonics of a power distribution network and converter voltage and current harmonics
And the power quality interaction model of the converter and the power distribution network is jointly established by utilizing a plurality of power quality influence models. The model can be used for quantitatively carrying out power quality interaction analysis on a low-voltage power distribution network comprising a power electronic converter, and is used for revealing the reason for generating the power quality problem in the power distribution network and the contribution ratio of different reasons to the final problem, and providing directional guidance for power quality improvement engineering of the power distribution network.
In a specific embodiment of the present invention, a process for establishing an electric energy quality interaction mechanism model capable of fully characterizing an electric energy quality multi-index coupling relationship and an electric converter power distribution network multi-node coupling relationship includes: basic parameters of the converter and the power distribution network are extracted; and respectively establishing each electric energy quality influence factor model based on the operation mechanism and basic parameters of the converter and the power distribution network. And establishing a total interaction mechanism model of the electric energy quality of the converter and the power distribution network based on the interaction relation of the electric energy quality of the converter and the power distribution network.
In this embodiment, a typical converter topology is shown in fig. 2, and the converter refers to a typical two-stage photovoltaic converter, where basic parameters include: the photovoltaic cell maximum power point voltage standard value, the photovoltaic cell maximum power point current standard value, the photovoltaic cell light intensity standard value, the inverter direct current bus capacitance value, the inverter direct current bus voltage given value, the inverter closed loop transfer function, the inverter output impedance, the inverter direct current voltage outer loop proportional coefficient, the inverter direct current voltage outer loop integral coefficient and the power grid voltage nominal value.
In this embodiment, a typical power distribution network structure is shown in fig. 3, where the power distribution network refers to a typical low-voltage power distribution network, and basic parameters include: the power grid topology, rated voltage class, rated operating frequency, line impedance between nodes, converter capacity of nodes and load capacity of nodes.
In this embodiment, as shown in fig. 4, the building of each power quality influence factor model includes the following steps:
1) Establishing a fine harmonic mathematical model of the converter according to the operation mechanism and basic parameters of the converter, wherein the closed-loop transfer function of the converter can be obtained by the following formula:
wherein, ，/>， ，L 1 is the reverse ofThe inductance value of the transformer side,L 2 for the inductance value at the power grid side,Cin order to filter the value of the capacitance,ω 0 for the fundamental angular frequency of the grid,K pwm for the equivalent gain of the inverter,H i1 for the sampling scaling factor of the capacitive current,H i2 sampling proportionality coefficient for grid-connected current, < >>Is the transfer function of the current inner loop compensator.
The converter output impedance can be obtained by
Wherein, 。
the fine harmonic mathematical model of the converter can be obtained as
2) Establishing a power quality interaction mathematical model of the power distribution network according to the operation mechanism and basic parameters of the converter
Wherein, I inv_i for the output current of the inverter on node i,I invref_i the inverter output current on node i is given a value,U grid_i for the grid voltage on node i,U d for the converter voltage drop due to non-linear factors,Z o is the equivalent output resistance of the current converter,I inv_k for the inverter output current on node k,Z f_k for the line impedance at node k,U p grid background Voltage for PCC node。
3) Establishing a three-phase unbalanced harmonic power fluctuation coupling model according to the influence mechanism of the three-phase unbalance on the converter
Wherein, ，i rms as an effective value of the current, the current is,i rms1 the effective value of the current fundamental wave, alpha and beta are parameter factors for adjusting power fluctuation and current harmonic wave in the converter controller, n is negative sequence unbalance degree, P is output instantaneous power, and P is output average power.
4) Establishing a transient coupling model of voltage deviation of light intensity variation according to the influence mechanism of the light intensity variation on the converter
Wherein, G S2Iod is a transfer function from the illumination intensity of the two-stage inversion photovoltaic system to the d-axis component of the output current,V mref is the standard value of the maximum power point voltage of the photovoltaic cell,I mref is the standard value of the maximum power point current of the photovoltaic cell,C DC is the capacitance value of the direct current bus capacitor,V DCef is the voltage reference value of the bus capacitor of the inverter,K p as the external ring scaling factor of the inverter voltage,K i for the outer loop integral coefficient of the inverter voltage,G cl_dd for the d-axis component of the inverter closed loop transfer function matrix,V g_d as a d-axis component of the grid voltage,S ref and the standard value of the illumination intensity of the photovoltaic cell.
5) Establishing a harmonic coupling model of the power grid background harmonic converter according to the influence mechanism of the power grid background harmonic on the converter
Wherein, I h for the distorted current output by the inverter,I ref for the output current reference value of the inverter,U h is the distorted voltage of the power grid background.
6) And (3) integrating the models represented by the formulas (3), (4), (5), (6) and (7), and establishing a total model of the interaction mechanism of the converter and the power quality of the power distribution network based on multi-index coupling.
Specifically, a total model of the interaction mechanism of the power quality of the converter and the power distribution network is shown in fig. 5. Wherein, formula (3) quantitatively characterizes the inverter voltage harmonic current harmonic problem which will be caused by the power electronic switch modulation process. Equation (6) quantitatively characterizes the voltage deviation and voltage transient problems of the converter nodes caused by the change of the light intensity and the converter power command. Equation (7) quantitatively characterizes the problem of interaction influence between the voltage and current harmonics of the power distribution network and the voltage and current harmonics of the converter. Equation (5) quantitatively characterizes the problems of converter voltage harmonic waves, current harmonic waves and voltage deviation caused by three-phase unbalance of the power distribution network voltage. The formula (4) quantitatively characterizes the interactive influence problem among the voltage harmonic wave, the current harmonic wave, the three-phase unbalance, the voltage deviation and the voltage transient of the power distribution network and the voltage harmonic wave, the current harmonic wave, the three-phase unbalance, the voltage deviation and the voltage transient of the converter.
The model shown in fig. 5 can be used for quantitatively performing power quality interaction analysis on a low-voltage power distribution network comprising a power electronic converter, so as to reveal the reason for the generation of power quality problems in the power distribution network and the contribution ratio of different reasons to the final problem, and provide directional guidance for power quality improvement engineering of the power distribution network.
According to the invention, quantitative electric energy quality interaction analysis is carried out on the low-voltage power distribution network comprising the power electronic converter, and an electric energy quality interaction model of the converter and the power distribution network is established, so that the multi-index coupling relation of the electric energy quality is fully represented, quantitative mathematical analysis is carried out on voltage harmonic waves, current harmonic waves, three-phase imbalance, voltage deviation and voltage transient electric energy quality interaction between the power electronic converter and the low-voltage power distribution network, the disclosure of the cause of electric energy quality problems in the power distribution network and the contribution ratio of different causes to final problems are facilitated, and directional guidance is provided for power quality improvement engineering of the power distribution network.
Fig. 6 is a schematic structural diagram of an interactive processing device for power quality of a converter and a power distribution network according to an embodiment of the present invention, where the device includes:
the power quality module 10 is configured to obtain a basic parameter of the converter and a basic parameter of the power distribution network, and determine a plurality of power quality influence models according to the basic parameter of the converter and the basic parameter of the power distribution network;
the interaction analysis module 20 is configured to establish an interaction model of the power quality of the converter and the power distribution network by using the power quality influence model; the power quality interaction model of the converter and the power distribution network is used for quantitatively analyzing and processing power quality interaction of the power distribution network comprising the converter.
As one embodiment of the invention, the basic parameters of the converter comprise a photovoltaic cell maximum power point voltage standard value, a photovoltaic cell maximum power point current standard value, a photovoltaic cell light intensity standard value, an inverter direct current bus capacitance value, an inverter direct current bus voltage given value, an inverter closed loop transfer function, an inverter output impedance, an inverter direct current voltage outer loop proportional coefficient, an inverter direct current voltage outer loop integral coefficient and a power grid voltage nominal value.
As one embodiment of the invention, the basic parameters of the power distribution network include the topology of the power network, rated voltage class, rated operating frequency, line impedance between nodes, capacity of the converter of each node and load capacity of each node.
As one embodiment of the invention, the power quality influence model comprises a converter fine harmonic mathematical model, a power quality interaction mathematical model of a power distribution network, a three-phase unbalanced harmonic power fluctuation coupling model, a light intensity variation voltage deviation transient coupling model and a power grid background harmonic converter harmonic coupling model.
Based on the same application conception as the method for interactively processing the power quality of the converter and the power distribution network, the invention also provides a device for interactively processing the power quality of the converter and the power distribution network. Because the principle of the device for processing the power quality interaction of the current converter and the power distribution network is similar to that of the method for processing the power quality interaction of the current converter and the power distribution network, the implementation of the device for processing the power quality interaction of the current converter and the power distribution network can be referred to the implementation of the method for processing the power quality interaction of the current converter and the power distribution network, and the repetition is omitted.
According to the invention, quantitative electric energy quality interaction analysis is carried out on the low-voltage power distribution network comprising the power electronic converter, and an electric energy quality interaction model of the converter and the power distribution network is established, so that the multi-index coupling relation of the electric energy quality is fully represented, quantitative mathematical analysis is carried out on voltage harmonic waves, current harmonic waves, three-phase imbalance, voltage deviation and voltage transient electric energy quality interaction between the power electronic converter and the low-voltage power distribution network, the disclosure of the cause of electric energy quality problems in the power distribution network and the contribution ratio of different causes to final problems are facilitated, and directional guidance is provided for power quality improvement engineering of the power distribution network.
The invention also provides an electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the above method when executing the program.
The invention also provides a computer program product comprising computer programs/instructions which when executed by a processor implement the steps of the above method.
The present invention also provides a computer-readable storage medium storing a computer program for executing the above method by a computer.
As shown in fig. 7, the electronic device 600 may further include: a communication module 110, an input unit 120, an audio processor 130, a display 160, a power supply 170. It is noted that the electronic device 600 need not include all of the components shown in fig. 7; in addition, the electronic device 600 may further include components not shown in fig. 7, to which reference is made to the related art.
As shown in fig. 7, the central processor 100, sometimes also referred to as a controller or operational control, may include a microprocessor or other processor device and/or logic device, which central processor 100 receives inputs and controls the operation of the various components of the electronic device 600.
The memory 140 may be, for example, one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, or other suitable device. The information about failure may be stored, and a program for executing the information may be stored. And the central processor 100 can execute the program stored in the memory 140 to realize information storage or processing, etc.
The input unit 120 provides an input to the central processor 100. The input unit 120 is, for example, a key or a touch input device. The power supply 170 is used to provide power to the electronic device 600. The display 160 is used for displaying display objects such as images and characters. The display may be, for example, but not limited to, an LCD display.
The memory 140 may be a solid state memory such as Read Only Memory (ROM), random Access Memory (RAM), SIM card, or the like. But also a memory which holds information even when powered down, can be selectively erased and provided with further data, an example of which is sometimes referred to as EPROM or the like. Memory 140 may also be some other type of device. Memory 140 includes a buffer memory 141 (sometimes referred to as a buffer). The memory 140 may include an application/function storage 142, the application/function storage 142 for storing application programs and function programs or a flow for executing operations of the electronic device 600 by the central processor 100.
The memory 140 may also include a data store 143, the data store 143 for storing data, such as contacts, digital data, pictures, sounds, and/or any other data used by the electronic device. The driver storage 144 of the memory 140 may include various drivers of the electronic device for communication functions and/or for performing other functions of the electronic device (e.g., messaging applications, address book applications, etc.).
The communication module 110 is a transmitter/receiver 110 that transmits and receives signals via an antenna 111. A communication module (transmitter/receiver) 110 is coupled to the central processor 100 to provide an input signal and receive an output signal, which may be the same as in the case of a conventional mobile communication terminal.
Based on different communication technologies, a plurality of communication modules 110, such as a cellular network module, a bluetooth module, and/or a wireless local area network module, etc., may be provided in the same electronic device. The communication module (transmitter/receiver) 110 is also coupled to a speaker 131 and a microphone 132 via an audio processor 130 to provide audio output via the speaker 131 and to receive audio input from the microphone 132 to implement usual telecommunication functions. The audio processor 130 may include any suitable buffers, decoders, amplifiers and so forth. In addition, the audio processor 130 is also coupled to the central processor 100 so that sound can be recorded locally through the microphone 132 and so that sound stored locally can be played through the speaker 131.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The principles and embodiments of the present invention have been described in detail with reference to specific examples, which are provided to facilitate understanding of the method and core ideas of the present invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (8)
1. An interactive processing method for power quality of a converter and a power distribution network is characterized by comprising the following steps:
acquiring basic parameters of a converter and basic parameters of a power distribution network, and determining a plurality of electric energy quality influence models according to the basic parameters of the converter and the basic parameters of the power distribution network;
establishing an electric energy quality interaction model of the converter and the power distribution network by using the electric energy quality influence model; the converter and power distribution network power quality interaction model is used for quantitatively analyzing and processing power quality interaction of a power distribution network comprising the converter;
the method for establishing the power quality interaction model of the converter and the power distribution network comprises the following steps of:
establishing a fine harmonic mathematical model of the converter according to the operation mechanism and basic parameters of the converter, wherein the closed-loop transfer function of the converter can be obtained by the following formula:
；
wherein, ，
， L 1 for the inductance value of the inverter side,L 2 for the inductance value at the power grid side,Cin order to filter the value of the capacitance,ω 0 for the fundamental angular frequency of the grid,K pwm for the equivalent gain of the inverter,H i1 for the sampling scaling factor of the capacitive current,H i2 sampling proportionality coefficient for grid-connected current, < >>Is a transfer function of the current inner loop compensator;
the inverter output impedance may be obtained by:
；
wherein, ；
the fine harmonic mathematical model of the converter can be obtained as follows:
；
establishing a power quality interaction mathematical model of the power distribution network according to the operation mechanism of the converter and basic parameters:
；
wherein, I inv_i for the output current of the inverter on node i,I invref_i the inverter output current on node i is given a value,U grid_i for the grid voltage on node i,U d for the converter voltage drop due to non-linear factors,Z o is the equivalent output resistance of the current converter,I inv_k for the inverter output current on node k,Z f_k for the line impedance at node k, U p the PCC node power grid background voltage;
establishing a three-phase unbalanced harmonic power fluctuation coupling model according to the influence mechanism of the three-phase unbalance on the converter:
；
wherein, ，i rms as an effective value of the current, the current is,i rms1 the effective value of the current fundamental wave, alpha and beta are parameter factors for adjusting power fluctuation and current harmonic waves in the converter controller, n is negative sequence unbalance degree, P is output instantaneous power, and P is output average power;
establishing a light intensity change voltage deviation transient coupling model according to the influence mechanism of the light intensity change on the converter:
；
wherein, G S2Iod is a transfer function from the illumination intensity of the two-stage inversion photovoltaic system to the d-axis component of the output current,V mref is the standard value of the maximum power point voltage of the photovoltaic cell,I mref is the standard value of the maximum power point current of the photovoltaic cell,C DC is the capacitance value of the direct current bus capacitor,V DCref is the voltage reference value of the bus capacitor of the inverter,K p as the external ring scaling factor of the inverter voltage,K i for the outer loop integral coefficient of the inverter voltage,G cl_dd for the d-axis component of the inverter closed loop transfer function matrix,V g_d as a d-axis component of the grid voltage,S ref the illumination intensity standard value of the photovoltaic cell;
establishing a harmonic coupling model of the power grid background harmonic converter according to the influence mechanism of the power grid background harmonic on the converter:
；
wherein, I h for the distorted current output by the inverter,I ref for the output current reference value of the inverter,U h the distortion voltage is the power grid background;
and establishing a multi-index coupling-based converter and power quality interaction model of the power distribution network according to each model represented by the formula.
2. The method of claim 1, wherein the inverter base parameters include a photovoltaic cell maximum power point voltage standard value, a photovoltaic cell maximum power point current standard value, a photovoltaic cell light intensity standard value, an inverter direct current bus capacitance value, an inverter direct current bus voltage setpoint value, an inverter closed loop transfer function, an inverter output impedance, an inverter direct current voltage outer loop scaling factor, an inverter direct current voltage outer loop integration factor, and a grid voltage nominal value.
3. The method of claim 1, wherein the power distribution network base parameters include power network topology, rated voltage class, rated operating frequency, inter-node line impedance, node inverter capacity, and node load capacity.
4. An interactive processing device for power quality of a converter and a power distribution network, which is characterized by comprising:
the power quality module is used for acquiring basic parameters of the current converter and basic parameters of the power distribution network and determining a plurality of power quality influence models according to the basic parameters of the current converter and the basic parameters of the power distribution network;
the interaction analysis module is used for establishing an electric energy quality interaction model of the converter and the power distribution network by utilizing the electric energy quality influence model; the converter and power distribution network power quality interaction model is used for quantitatively analyzing and processing power quality interaction of a power distribution network comprising the converter;
wherein, the power quality module and the interaction analysis module are further configured to:
establishing a fine harmonic mathematical model of the converter according to the operation mechanism and basic parameters of the converter, wherein the closed-loop transfer function of the converter can be obtained by the following formula:
；
wherein, ，
， L 1 for the inductance value of the inverter side,L 2 for the inductance value at the power grid side,Cin order to filter the value of the capacitance,ω 0 for the fundamental angular frequency of the grid,K pwm for the equivalent gain of the inverter,H i1 for the sampling scaling factor of the capacitive current,H i2 sampling proportionality coefficient for grid-connected current, < >>Is a transfer function of the current inner loop compensator;
the inverter output impedance may be obtained by:
；
wherein, ；
the fine harmonic mathematical model of the converter can be obtained as follows:
；
establishing a power quality interaction mathematical model of the power distribution network according to the operation mechanism of the converter and basic parameters:
；
wherein, I inv_i for the output current of the inverter on node i,I invref_i the inverter output current on node i is given a value,U grid_i for the grid voltage on node i,U d for the converter voltage drop due to non-linear factors,Z o is the equivalent output resistance of the current converter,I inv_k for the inverter output current on node k,Z f_k for the line impedance at node k, U p the PCC node power grid background voltage;
establishing a three-phase unbalanced harmonic power fluctuation coupling model according to the influence mechanism of the three-phase unbalance on the converter:
；
wherein, ，i rms as an effective value of the current, the current is,i rms1 the effective value of the current fundamental wave, alpha and beta are parameter factors for adjusting power fluctuation and current harmonic waves in the converter controller, n is negative sequence unbalance degree, P is output instantaneous power, and P is output average power;
establishing a light intensity change voltage deviation transient coupling model according to the influence mechanism of the light intensity change on the converter:
；
wherein, G S2Iod is a transfer function from the illumination intensity of the two-stage inversion photovoltaic system to the d-axis component of the output current,V mref is the standard value of the maximum power point voltage of the photovoltaic cell,I mref is the standard value of the maximum power point current of the photovoltaic cell,C DC is the capacitance value of the direct current bus capacitor,V DCref is the voltage reference value of the bus capacitor of the inverter,K p as the external ring scaling factor of the inverter voltage,K i for the outer loop integral coefficient of the inverter voltage,G cl_dd for the d-axis component of the inverter closed loop transfer function matrix,V g_d as a d-axis component of the grid voltage,S ref the illumination intensity standard value of the photovoltaic cell;
establishing a harmonic coupling model of the power grid background harmonic converter according to the influence mechanism of the power grid background harmonic on the converter:
；
wherein, I h for the distorted current output by the inverter,I ref for the output current reference value of the inverter,U h the distortion voltage is the power grid background;
and establishing a multi-index coupling-based converter and power quality interaction model of the power distribution network according to each model represented by the formula.
5. The apparatus of claim 4, wherein the inverter base parameters include a photovoltaic cell maximum power point voltage standard value, a photovoltaic cell maximum power point current standard value, a photovoltaic cell light intensity standard value, an inverter direct current bus capacitance value, an inverter direct current bus voltage set point, an inverter closed loop transfer function, an inverter output impedance, an inverter direct current voltage outer loop scaling factor, an inverter direct current voltage outer loop integration factor, and a grid voltage nominal value.
6. The apparatus of claim 4, wherein the power distribution network base parameters include power network topology, rated voltage class, rated operating frequency, inter-node line impedance, node inverter capacity, and node load capacity.
7. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method of any one of claims 1 to 3 when executing the computer program.
8. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program for executing the method of any one of claims 1 to 3 by a computer.
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