CN113098047A - Flexible direct-current power grid control method, device, equipment and storage medium - Google Patents

Flexible direct-current power grid control method, device, equipment and storage medium Download PDF

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Publication number
CN113098047A
CN113098047A CN202110520204.8A CN202110520204A CN113098047A CN 113098047 A CN113098047 A CN 113098047A CN 202110520204 A CN202110520204 A CN 202110520204A CN 113098047 A CN113098047 A CN 113098047A
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reference value
voltage
grid
value
component
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CN113098047B (en
Inventor
陈怡静
李力
黄伟煌
敖健永
蔡东晓
谭涛亮
李岩
陆秋瑜
赵晓斌
黎带珍
许数楷
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Yangjiang Power Supply Bureau of Guangdong Power Grid Co Ltd
Research Institute of Southern Power Grid Co Ltd
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Yangjiang Power Supply Bureau of Guangdong Power Grid Co Ltd
Research Institute of Southern Power Grid Co Ltd
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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
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • 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
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H02J3/241—The oscillation concerning frequency
    • 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
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/48—Controlling the sharing of the in-phase component
    • 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
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/50—Controlling the sharing of the out-of-phase component
    • 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
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • H02J2003/365—Reducing harmonics or oscillations in HVDC
    • 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
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • 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)
  • Inverter Devices (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention discloses a flexible direct current power grid control method, a device, equipment and a storage medium, wherein a secondary frequency modulation control model is introduced, so that the frequency modulation and voltage regulation characteristics of a synchronous motor can be fully applied to a direct current power transmission system, the characteristics of the synchronous motor of a direct current system are further simulated, the direct current system can be more conveniently equivalent to the synchronous motor power grid, the system change can be responded in millisecond level, the reactive/active power, voltage and current of the direct current system are regulated, and the stability of the direct current system is maintained.

Description

Flexible direct-current power grid control method, device, equipment and storage medium
Technical Field
The invention relates to the technical field of power electronic control, in particular to a method, a device, equipment and a storage medium for controlling a flexible direct-current power grid.
Background
With the continuous improvement of the proportion of large-capacity power electronic equipment in the system, the power grid faces a brand new evolution mode, and the traditional stability problem taking the synchronous machine as the main factor is changed into a novel stability problem taking the control of the power electronic equipment as the main factor.
At present, an engineering control method of a flexible direct current transmission system is mainly a constant active/reactive-current inner and outer loop vector control method based on a voltage Phase Locked Loop (PLL). Under the control method, the flexible direct current transmission system presents strong rigidity, namely the direct current system is insensitive to the changes of the voltage, the frequency, the amplitude and the initial phase of the connected alternating current power grid, and the active/reactive output of the flexible direct current transmission system cannot be automatically adjusted to correspond to the changes of the connected power grid like a synchronous motor is taken as a main power grid.
Disclosure of Invention
The embodiment of the invention provides a method, a device, equipment and a storage medium for controlling a flexible direct current power grid, which can conveniently and quickly enable a direct current system to be equivalent to a synchronous motor power grid, quickly respond, adjust the active/reactive output of the direct current system and improve the stability of the direct current system access system.
An embodiment of the present invention provides a method for controlling a flexible dc power grid, where the method includes:
acquiring a voltage measurement value and a frequency measurement value of an alternating current grid-connected point of a converter station, and outputting an active power reference value and a reactive power reference value according to the voltage measurement value, the frequency measurement value and a preset secondary frequency modulation control model;
measuring the active power and the reactive power of the grid-connected point, and outputting an alternating voltage phase angle reference value and an alternating voltage amplitude reference value of the grid-connected point according to the active power reference value, the reactive power reference value, a preset active power control model and a preset reactive power control model;
measuring the alternating voltage measured value of the grid-connected point, carrying out park transformation on the alternating voltage measured value according to the alternating voltage phase angle reference value, transforming the three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating voltage dq component value of the grid-connected point; setting a voltage reference value of an alternating voltage d component of the grid-connected point as the alternating voltage amplitude reference value, and setting a voltage reference value of an alternating voltage q component of the grid-connected point as zero; controlling the alternating voltage dq component value according to a set voltage reference value of an alternating voltage d component, a set voltage reference value of an alternating voltage q component and a preset voltage control model, and outputting a current dq component reference value;
measuring the alternating current measured value of the grid-connected point, carrying out park transformation on the alternating current measured value according to the alternating voltage phase angle reference value, transforming the three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating current dq component value of the grid-connected point; controlling the alternating current dq component value according to the current dq component reference value and a preset current control model, and outputting a valve side voltage dq component reference value of the converter station; and performing park inverse transformation on the reference value of the dq component of the valve side voltage according to the reference value of the phase angle of the alternating voltage, performing inverse transformation from a dq coordinate system to an abc coordinate system, and outputting a three-phase voltage reference wave of the converter for a control link of the converter valve.
As a preferred mode, the obtaining a voltage measurement value and a frequency measurement value of an ac grid-connected point of a converter station, and outputting an active power reference value and a reactive power reference value according to the voltage measurement value, the frequency measurement value, and a preset secondary frequency modulation control model specifically includes:
obtaining a voltage measurement value of an alternating current grid-connected point of a converter station to obtain an amplitude V of an alternating current power supply of the grid-connected pointmAnd the AC power frequency f of the grid-connected pointm；
Through secondary frequency modulation control model:
Figure 47070DEST_PATH_IMAGE001
and
Figure 130301DEST_PATH_IMAGE002
outputting a power reference value comprising: reference value of active power PrefAnd a reactive power reference value QrefWherein, in the step (A),
frefand VmrefRespectively a frequency nominal reference value and a voltage nominal reference value, P, of said grid-connected pointnomAnd QnomRated active power and rated reactive power, P, respectively, for the design of the main circuit of the DC systemsetAnd QsetReference value of secondary frequency modulation active power and reference value of secondary frequency modulation reactive power, T, set for a scheduling system respectivelypAnd TqRespectively an active power time constant control parameter and a reactive power time constant control parameter, sigma, for determining the secondary frequency modulation dynamic response timepAnd σqRespectively an active power secondary frequency modulation contribution factor and a reactive power secondary frequency modulation contribution factor.
As a preferred mode, the measuring active power and reactive power of the grid-connected point, and outputting an ac voltage phase angle reference value and an ac voltage amplitude reference value of the grid-connected point according to the active power reference value, the reactive power reference value, a preset active power control model, and a preset reactive power control model specifically includes:
measuring the active power P and the reactive power Q of the grid-connected point, and according to the active reference value and the reactive power reference value; an active power control model and a reactive power control model constructed according to a synchronous generator equation of motion:
Figure DEST_PATH_IMAGE003
and
Figure 330207DEST_PATH_IMAGE004
generating the AC voltage phase angle reference value of the grid-connected pointƟAnd the reference value V of the amplitude of the alternating voltagemr(ii) a Wherein the content of the first and second substances,
Jpand JqRespectively, virtual synchronous control of inertia constant, DPAnd DqRespectively an active reactive power virtual synchronous control regulating constant and a reactive power virtual synchronous control regulating constant omegarefNominal reference value f for the frequency of the grid-connection pointrefAngular velocity of (i.e.,. omega.)ref =2πfref。
Preferably, the ac voltage measurement value of the grid-connected point is measured, park transformation is performed on the ac voltage measurement value according to the ac voltage phase angle reference value, a three-phase ac electric quantity is transformed from an abc coordinate system to a dq coordinate system, and an ac voltage dq component value of the grid-connected point is output; setting a voltage reference value of an alternating voltage d component of the grid-connected point as the alternating voltage amplitude reference value, and setting a voltage reference value of an alternating voltage q component of the grid-connected point as zero; controlling the value of the dq component of the alternating voltage according to a set voltage reference value of the d component of the alternating voltage, a set voltage reference value of the q component of the alternating voltage and a preset voltage control model, and outputting a reference value of the dq component of the current, specifically comprising:
by measuring the AC voltage measurement V of the point of connectionabcAccording to the phase angle reference value of the AC voltageƟMeasuring the AC voltage value VabcCarrying out park transformation, transforming the three-phase alternating current electric quantity from an abc coordinate system to a dq coordinate system to obtain an alternating voltage dq component voltage value Vdq；
Setting the reference value V of the amplitude of the AC voltagemrFor d component V of said alternating voltagedVoltage reference value VdrefSetting 0 as said component V of the AC voltage qqReference value V ofqrefI.e. Vdref=Vmr，Vqref=0。
Respectively according to d components V of the AC voltagedVoltage reference value VdrefAnd an alternating voltage q component VqVoltage reference value VqrefFor the component V of the alternating voltage dqdAnd VqControl is performed to output a reference value I of an alternating current dq componentdrefAnd Iqref。
Preferably, the alternating current measured value of the grid-connected point is measured, park transformation is performed on the alternating current measured value according to the alternating voltage phase angle reference value, a three-phase alternating current capacity is transformed from an abc coordinate system to a dq coordinate system, and an alternating current dq component value of the grid-connected point is output; controlling the alternating current dq component value according to the current dq component reference value and a preset current control model, and outputting a valve side voltage dq component reference value of the converter station; according to the alternating voltage phase angle reference value, carrying out park inverse transformation on the valve side voltage dq component reference value, carrying out inverse transformation from a dq coordinate system to an abc coordinate system, and outputting a converter three-phase voltage reference wave for a converter valve control link, wherein the method specifically comprises the following steps:
by measuring the AC current measured value I of the grid-connected pointabcAccording to the phase angle reference value of the AC voltageƟThe actual value I of the three-phase alternating currentabcCarrying out park transformation, transforming the three-phase alternating current magnitude from abc coordinate system to dq coordinate system to obtain the grid-connected point alternating current dq component current value Idq；
Through the use of the current control model,so that the grid-connected point AC current dq component IdAnd IqRespectively following the current reference values IdrefAnd IqrefGenerating a valve-side voltage dq component reference wave VcdrefAnd Vcqref；
According to the reference value of the phase angle of the AC voltageƟInverse park transformation is carried out on the valve side voltage reference wave, and inverse transformation is carried out on the dq coordinate system to the abc coordinate system to obtain a valve side three-phase voltage reference wave VcabcAnd the input quantity is used as the input quantity of the control link of the converter valve.
Another embodiment of the present invention provides a flexible dc power network control apparatus, including: the device comprises a power reference value setting module, a power control module, a voltage control module and a current control module;
the power reference value setting module is used for acquiring a voltage measurement value and a frequency measurement value of an alternating current grid-connected point of the converter station, and outputting an active power reference value and a reactive power reference value according to the voltage measurement value, the frequency measurement value and a preset secondary frequency modulation control model;
the power control module is used for measuring the active power and the reactive power of the grid-connected point and outputting an alternating voltage phase angle reference value and an alternating voltage amplitude reference value of the grid-connected point according to the active power reference value, the reactive power reference value, a preset active power control model and a preset reactive power control model;
the voltage control module is used for measuring an alternating voltage measured value of the grid-connected point, carrying out park transformation on the alternating voltage measured value according to the alternating voltage phase angle reference value, transforming a three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating voltage dq component value of the grid-connected point; setting a voltage reference value of an alternating voltage d component of the grid-connected point as the alternating voltage amplitude reference value, and setting a voltage reference value of an alternating voltage q component of the grid-connected point as zero; controlling the alternating voltage dq component value according to a set voltage reference value of an alternating voltage d component, a set voltage reference value of an alternating voltage q component and a preset voltage control model, and outputting a current dq component reference value;
the current control module is used for measuring an alternating current measured value of the grid-connected point, carrying out park transformation on the alternating current measured value according to the alternating voltage phase angle reference value, transforming a three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating current dq component value of the grid-connected point; controlling the alternating current dq component value according to the current dq component reference value and a preset current control model, and outputting a valve side voltage dq component reference value of the converter station; and performing park inverse transformation on the reference value of the dq component of the valve side voltage according to the reference value of the phase angle of the alternating voltage, performing inverse transformation from a dq coordinate system to an abc coordinate system, and outputting a three-phase voltage reference wave of the converter for a control link of the converter valve.
As a preferred mode, the power reference value setting module is specifically configured to:
obtaining a voltage measurement value of an alternating current grid-connected point of a converter station to obtain an amplitude V of an alternating current power supply of the grid-connected pointmAnd the AC power frequency f of the grid-connected pointm；
Through secondary frequency modulation control model:
Figure DEST_PATH_IMAGE005
and
Figure 461980DEST_PATH_IMAGE006
outputting a power reference value comprising: reference value of active power PrefAnd a reactive power reference value QrefWherein, in the step (A),
frefand VmrefRespectively a frequency nominal reference value and a voltage nominal reference value, P, of said grid-connected pointnomAnd QnomRated active power and rated reactive power, P, respectively, for the design of the main circuit of the DC systemsetAnd QsetReference value of secondary frequency modulation active power and reference value of secondary frequency modulation reactive power, T, set for a scheduling system respectivelypAnd TqRespectively an active power time constant control parameter and a reactive power time constant control parameter, sigma, for determining the secondary frequency modulation dynamic response timepAnd σqRespectively as active power secondary frequency modulation contribution factor and reactive powerSecondary frequency modulation contributing factors.
As a preferred mode, the power control module is specifically configured to:
measuring the active power P and the reactive power Q of the grid-connected point, and according to the active reference value and the reactive power reference value; an active power control model and a reactive power control model constructed according to a synchronous generator equation of motion:
Figure DEST_PATH_IMAGE007
and
Figure 689830DEST_PATH_IMAGE008
generating the AC voltage phase angle reference value of the grid-connected pointƟAnd the reference value V of the amplitude of the alternating voltagemr(ii) a Wherein the content of the first and second substances,
Jpand JqRespectively, virtual synchronous control of inertia constant, DPAnd DqRespectively an active reactive power virtual synchronous control regulating constant and a reactive power virtual synchronous control regulating constant, omegarefNominal reference value f for the frequency of the grid-connection pointrefAngular velocity of (i.e.,. omega.)ref =2πfref。
As a preferred mode, the voltage control module is specifically configured to:
by measuring the AC voltage measurement V of the point of connectionabcAccording to the phase angle reference value of the AC voltageƟMeasuring the AC voltage value VabcCarrying out park transformation, transforming the three-phase alternating current electric quantity from an abc coordinate system to a dq coordinate system to obtain an alternating voltage dq component voltage value Vdq；
Setting the reference value V of the amplitude of the AC voltagemrFor d component V of said alternating voltagedVoltage reference value VdrefSetting 0 as said component V of the AC voltage qqReference value V ofqrefI.e. Vdref=Vmr，Vqref=0。
Respectively according to d components V of the AC voltagedVoltage reference value VdrefAnd an alternating voltage q component VqVoltage reference value VqrefFor the component V of the alternating voltage dqdAnd VqControl is performed to output a reference value I of an alternating current dq componentdrefAnd Iqref。
As a preferred mode, the current control module is specifically configured to:
by measuring the AC current measured value I of the grid-connected pointabcAccording to the phase angle reference value of the AC voltageƟThe actual value I of the three-phase alternating currentabcCarrying out park transformation, transforming the three-phase alternating current magnitude from abc coordinate system to dq coordinate system to obtain the grid-connected point alternating current dq component current value Idq；
Leading the grid-connected point alternating current dq component I to pass through a current control modeldAnd IqRespectively following the current reference values IdrefAnd IqrefGenerating a valve-side voltage dq component reference wave VcdrefAnd Vcqref；
According to the reference value of the phase angle of the AC voltageƟInverse park transformation is carried out on the valve side voltage reference wave, and inverse transformation is carried out on the dq coordinate system to the abc coordinate system to obtain a valve side three-phase voltage reference wave VcabcAnd the input quantity is used as the input quantity of the control link of the converter valve.
Another embodiment of the present invention provides a storage medium, where the computer-readable storage medium includes a stored computer program, where when the computer program runs, a device where the computer-readable storage medium is located is controlled to execute the flexible direct current power grid control method according to the above-described embodiment of the present invention.
Another embodiment of the present invention provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, and when the processor executes the computer program, the processor implements the flexible direct current power grid control method according to the above embodiment of the present invention.
According to the flexible direct current power grid control method, device, equipment and storage medium, the secondary frequency modulation control model is introduced, the frequency modulation and voltage regulation characteristics of the synchronous motor can be fully applied to a direct current power transmission system, the characteristics of the synchronous motor of the direct current system are further simulated, the direct current system can be more conveniently equivalent to the synchronous motor power grid, the system change can be responded in millisecond level, the reactive/active power, voltage and current of the direct current system are regulated, and the stability of the direct current system is maintained.
Drawings
Fig. 1 is a schematic flow chart of a flexible dc power grid control method according to an embodiment of the present invention;
fig. 2 is a block diagram of an active power reference value generated by a secondary frequency modulation control model according to an embodiment of the present invention;
fig. 3 is a block diagram of a reactive power reference value generated by a secondary frequency modulation control model according to an embodiment of the present invention;
FIG. 4 is a control framework diagram of a power control model according to an embodiment of the present invention;
FIG. 5 is a control framework diagram of a voltage control model according to an embodiment of the present invention;
FIG. 6 is a control framework diagram of a current control model according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a flexible dc power network control device according to an embodiment of the present invention;
fig. 8 is a schematic diagram of a terminal device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, a schematic flow chart of a method for controlling a flexible dc power grid according to an embodiment of the present invention is shown, and the method includes steps S101 to S104:
s101, acquiring a voltage measurement value and a frequency measurement value of an alternating current grid-connected point of a converter station, and outputting an active power reference value and a reactive power reference value according to the voltage measurement value, the frequency measurement value and a preset secondary frequency modulation control model;
s102, measuring the active power and the reactive power of the grid-connected point, and outputting an alternating voltage phase angle reference value and an alternating voltage amplitude reference value of the grid-connected point according to the active power reference value, the reactive power reference value, a preset active power control model and a preset reactive power control model;
s103, measuring the alternating voltage measured value of the grid-connected point, carrying out park transformation on the alternating voltage measured value according to the alternating voltage phase angle reference value, transforming a three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating voltage dq component value of the grid-connected point; setting a voltage reference value of an alternating voltage d component of the grid-connected point as the alternating voltage amplitude reference value, and setting a voltage reference value of an alternating voltage q component of the grid-connected point as zero; controlling the alternating voltage dq component value according to a set voltage reference value of an alternating voltage d component, a set voltage reference value of an alternating voltage q component and a preset voltage control model, and outputting a current dq component reference value;
s104, measuring the alternating current measured value of the grid-connected point, carrying out park transformation on the alternating current measured value according to the alternating voltage phase angle reference value, transforming the three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating current dq component value of the grid-connected point; controlling the alternating current dq component value according to the current dq component reference value and a preset current control model, and outputting a valve side voltage dq component reference value of the converter station; and performing park inverse transformation on the reference value of the dq component of the valve side voltage according to the reference value of the phase angle of the alternating voltage, performing inverse transformation from a dq coordinate system to an abc coordinate system, and outputting a three-phase voltage reference wave of the converter for a control link of the converter valve.
When the embodiment is implemented specifically, a voltage measurement value and a frequency measurement value of an alternating current grid-connected point of a converter station are obtained, the voltage measurement value and the frequency measurement value are input into a preset secondary frequency modulation control model, and an active power reference value and a reactive power reference value are output;
measuring an active power voltage value and a reactive power voltage value of a grid-connected point, inputting the active power voltage value, the reactive power voltage value and a power reference value into a power control model, adjusting the active power voltage value and the reactive power voltage value, and outputting a voltage reference value comprising a grid-connected point alternating-current voltage phase angle reference value and a voltage amplitude reference value;
controlling a network side voltage reference value according to the reference voltage value and a voltage control model, and outputting a current reference value;
and outputting a valve side voltage reference value according to the current reference value and a preset current control model, and controlling the flexible direct current converter according to the valve side voltage reference value.
The embodiment provides a secondary frequency modulation control model of a synchronous generator, further simulates the characteristics of a synchronous motor of a direct current system, can more conveniently enable the direct current system to be equivalent to a synchronous motor power grid, can respond to system changes in millisecond level, adjusts reactive/active power, voltage and current of the direct current system, and maintains the stability of the direct current system.
In another embodiment provided by the present invention, step S101 specifically includes:
obtaining voltage measurement value V of alternating current grid-connected point of converter stationmFrequency measurement fm；
Through secondary frequency modulation control model:
Figure DEST_PATH_IMAGE009
and
Figure 6280DEST_PATH_IMAGE010
outputting the active power reference value PrefAnd a reactive power reference value QrefWherein, in the step (A),
frefand VmrefRespectively a frequency nominal reference value and a voltage nominal reference value, P, of said grid-connected pointnomAnd QnomRated active power and rated reactive power, P, respectively, for the design of the main circuit of the DC systemsetAnd QsetReference value of secondary frequency modulation active power and reference value of secondary frequency modulation reactive power, T, set for a scheduling system respectivelypAnd TqRespectively, a time constant control parameter, σ, determining the dynamic response time of the secondary modulationpAnd σqRespectively, are secondary frequency modulation contributing factors for sigma when the voltage frequency or voltage of the grid-connected point deviatespAnd σqThe active/reactive power reference values are adjusted to minimize frequency and voltage amplitude deviations.
In the specific implementation of the embodiment, the voltage measurement value V at the ac grid-connected point of the converter station is measured firstmAnd a frequency measurement f at the grid connection pointm；
Through the control model of predetermined secondary frequency modulation:
Figure 381898DEST_PATH_IMAGE011
Figure 740198DEST_PATH_IMAGE012
obtaining a power reference value, wherein the power reference value comprises an active power reference value PrefAnd a reactive power reference value Qref(ii) a In addition, the secondary frequency modulation control model contains parameter information of the electric power system acquired in advance, and specifically includes: f. ofrefAnd VmrefRespectively a frequency nominal reference value and a voltage nominal reference value, P, of said grid-connected pointnomAnd QnomRated active power and rated reactive power, P, respectively, for the design of the main circuit of the DC systemsetAnd QsetReference value of secondary frequency modulation active power and reference value of secondary frequency modulation reactive power, T, set for a scheduling system respectivelypAnd TqRespectively an active power time constant control parameter and a reactive power time constant control parameter, sigma, for determining the secondary frequency modulation dynamic response timepAnd σqRespectively an active power secondary frequency modulation contribution factor and a reactive power secondary frequency modulation contribution factor.
Referring to fig. 2, it is a frame diagram of an active power reference value generated by a chirp control model according to an embodiment of the present invention, where when input quantities of the chirp control model are input: reference value f of frequency ratingrefFrequency measurement fmReference value P of secondary frequency modulation active power set by scheduling systemsetThe secondary frequency modulation control model is based on the frequency rated reference value frefRated active power P in designing main loop of DC systemnomContribution factor sigma of active power secondary frequency modulationpAnd an active power time constant control parameter TpOutputting the active power reference value Pref；
Referring to fig. 3, it is a block diagram of a reactive power reference value generated by a secondary frequency modulation control model according to an embodiment of the present invention, when an input value of the secondary frequency modulation control model is inputted, a voltage rating reference value V is shownmrefVoltage measurement value VmReference value Q of secondary frequency modulation reactive power set by dispatching systemsetThe secondary frequency modulation control model is based on a voltage rated reference value VmrefRated reactive power Q in designing main loop of direct current systemnomContribution factor sigma of reactive power secondary frequency modulationqAnd a reactive power time constant control parameter TqTo output a reactive power reference value Qref；
The power reference value is generated through the secondary frequency modulation control model to be a quasi-steady state control link, the dynamic response time precision is in the second level, and the deviation degree of the frequency amplitude and the voltage amplitude can be reduced through the generated active/reactive power reference value after the voltage or the frequency of the grid-connected point deviates.
In an embodiment of the present invention, the step S102 specifically includes:
obtaining a voltage measurement value of an alternating current grid-connected point of a converter station to obtain an amplitude V of an alternating current power supply of the grid-connected pointmAnd the AC power frequency f of the grid-connected pointm；
Through secondary frequency modulation control model:
Figure 150451DEST_PATH_IMAGE013
and
Figure 700118DEST_PATH_IMAGE014
outputting a power reference value comprising: reference value of active power PrefAnd a reactive power reference value QrefWherein, in the step (A),
frefand VmrefRespectively a frequency nominal reference value and a voltage nominal reference value, P, of said grid-connected pointnomAnd QnomRated active power and rated reactive power, P, respectively, for the design of the main circuit of the DC systemsetAnd QsetReference value of secondary frequency modulation active power and reference value of secondary frequency modulation reactive power, T, set for a scheduling system respectivelypAnd TqRespectively an active power time constant control parameter and a reactive power time constant control parameter, sigma, for determining the secondary frequency modulation dynamic response timepAnd σqRespectively an active power secondary frequency modulation contribution factor and a reactive power secondary frequency modulation contribution factor.
In the specific implementation of this embodiment, in the power control link, an active power voltage value P and a reactive power voltage value Q of the grid-connected point are measured first;
measuring the active power voltage value P and the reactive power voltage value Q and the active power reference value P output by the secondary frequency modulation control modelrefAnd a reactive power reference value QrefInputting to a preset power control model:
Figure 438398DEST_PATH_IMAGE015
Figure 98925DEST_PATH_IMAGE016
output voltage reference value, including, AC voltage phase angle reference valueƟAnd the reference value V of the amplitude of the alternating voltagemr；
Wherein P is the measured active power voltage value, Q is the measured reactive power voltage value,Ɵphase angle for connecting DC system to power grid, f is frequency of connected power grid, JpAnd JqRespectively, virtual synchronous control of inertia constant, DPAnd DqAdjusting constant omega for virtual synchronous control of active/reactive power respectivelyrefIs that it isFrequency nominal reference value f of grid-connected pointrefAngular velocity of (i.e.,. omega.)ref =2πfref。
In a steady state situation, the active power voltage value P = the active power reference value PrefFrequency of connected grid f = frequency nominal reference value frefWhen the frequency of the alternating current system connected with the direct current system changes, if the frequency rated reference value f is increased,Δf= f-f ref and if not equal to 0, the active power voltage value can be quickly adjusted to a new stable value under the action of the power control model, and the system is ensured to keep a balance point.
When the voltage value of the reactive power changes, the working principle is basically similar to the situation of the active power, and the details are not repeated herein.
Referring to fig. 4, it is a control frame diagram of a power control model according to an embodiment of the present invention, where an active power voltage value P and an active power reference value P are inputrefA reactive power voltage value Q and a reactive power reference value QrefThrough the illustrated process, the stabilization of the active/reactive power voltage can be accomplished and the voltage reference values Ɵ and V can be outputmr；
The response precision of the power control model is millisecond level, and is correspondingly a primary frequency modulation link controlled by a synchronous motor. The power control link simulates a motion equation of a synchronous generator, and the amplitude and the phase angle of the grid-side grid-connected point voltage are constructed through power control, so that the flexible-direct system has a self-synchronizing function and a rapid frequency and voltage modulation capability, and a phase-locked loop is not needed in the control link during normal operation.
In another embodiment provided by the present invention, step S103 specifically includes:
by measuring the AC voltage measurement V of the point of connectionabcAccording to the phase angle reference value of the AC voltageƟMeasuring the AC voltage value VabcCarrying out park transformation, transforming the three-phase alternating current electric quantity from an abc coordinate system to a dq coordinate system to obtain an alternating voltage dq component voltage value Vdq；
Setting the reference value V of the amplitude of the AC voltagemrFor d component V of said alternating voltagedVoltage reference value VdrefSetting 0 as said component V of the AC voltage qqReference value V ofqrefI.e. Vdref=Vmr，Vqref=0。
Respectively according to d components V of the AC voltagedVoltage reference value VdrefAnd an alternating voltage q component VqVoltage reference value VqrefFor the component V of the alternating voltage dqdAnd VqControl is performed to output a reference value I of an alternating current dq componentdrefAnd Iqref。
In this embodiment, referring to fig. 5, it is a control frame diagram of a voltage control model according to an embodiment of the present invention, which is respectively based on the reference values V of the grid-connected point ac voltage dq componentsdrefAnd VqrefFor the actual AC voltage dq component V of the grid-connected pointdAnd VqControlling to output a reference value I of a grid-connected point alternating current dq componentdrefAnd Iqref。。
In another embodiment provided by the present invention, step S104 specifically includes:
by measuring the AC current measured value I of the grid-connected pointabcAccording to the phase angle reference value of the AC voltageƟThe actual value I of the three-phase alternating currentabcCarrying out park transformation, transforming the three-phase alternating current magnitude from abc coordinate system to dq coordinate system to obtain the grid-connected point alternating current dq component current value Idq；
Leading the grid-connected point alternating current dq component I to pass through a current control modeldAnd IqRespectively following the current reference values IdrefAnd IqrefGenerating a valve-side voltage dq component reference wave VcdrefAnd Vcqref；
According to the reference value of the phase angle of the AC voltageƟInverse park transformation is carried out on the valve side voltage reference wave, and inverse transformation is carried out on the dq coordinate system to the abc coordinate system to obtain a valve side three-phase voltage reference wave VcabcAnd the input quantity is used as the input quantity of the control link of the converter valve.
In practical implementation of the present invention, referring to fig. 6, it is shown that the present invention provides a control of a current control modelAnd (5) making a frame drawing. Leading the grid-connected point alternating current dq component I to pass through a current control modeldAnd IqRespectively following the current reference values IdrefAnd IqrefGenerating a valve-side voltage dq component reference wave VcdrefAnd Vcqref；
According to the phase angle Ɵ, inverse park transformation is carried out on the valve side voltage reference wave, and the valve side three-phase voltage reference wave V is obtained by inverse transformation from a dq coordinate system to an abc coordinate systemcabcAnd the input quantity is used as the input quantity of the control link of the converter valve.
According to the flexible direct current power grid control method provided by the invention, the secondary frequency modulation control model is introduced, the frequency modulation and voltage regulation characteristics of the synchronous motor can be fully applied to the direct current power transmission system, the characteristics of the synchronous motor of the direct current system are further simulated, the direct current system can be more conveniently equivalent to the synchronous motor power grid, the system change can be responded in millisecond level, the reactive/active power, voltage and current of the direct current system are regulated, and the stability of the direct current system is maintained.
Referring to fig. 7, it is a schematic structural diagram of a preferred implementation of a flexible dc power network control apparatus provided in the present invention, including: the device comprises a power reference value setting module, a power control module, a voltage control module and a current control module;
the power reference value setting module is used for acquiring a voltage measurement value and a frequency measurement value of an alternating current grid-connected point of the converter station, and outputting an active power reference value and a reactive power reference value according to the voltage measurement value, the frequency measurement value and a preset secondary frequency modulation control model;
the power control module is used for measuring the active power and the reactive power of the grid-connected point and outputting an alternating voltage phase angle reference value and an alternating voltage amplitude reference value of the grid-connected point according to the active power reference value, the reactive power reference value, a preset active power control model and a preset reactive power control model;
the voltage control module is used for measuring an alternating voltage measured value of the grid-connected point, carrying out park transformation on the alternating voltage measured value according to the alternating voltage phase angle reference value, transforming a three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating voltage dq component value of the grid-connected point; setting a voltage reference value of an alternating voltage d component of the grid-connected point as the alternating voltage amplitude reference value, and setting a voltage reference value of an alternating voltage q component of the grid-connected point as zero; controlling the alternating voltage dq component value according to a set voltage reference value of an alternating voltage d component, a set voltage reference value of an alternating voltage q component and a preset voltage control model, and outputting a current dq component reference value;
the current control module is used for measuring an alternating current measured value of the grid-connected point, carrying out park transformation on the alternating current measured value according to the alternating voltage phase angle reference value, transforming a three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating current dq component value of the grid-connected point; controlling the alternating current dq component value according to the current dq component reference value and a preset current control model, and outputting a valve side voltage dq component reference value of the converter station; and performing park inverse transformation on the reference value of the dq component of the valve side voltage according to the reference value of the phase angle of the alternating voltage, performing inverse transformation from a dq coordinate system to an abc coordinate system, and outputting a three-phase voltage reference wave of the converter for a control link of the converter valve.
The specific functions of each module of the device are specifically described in any embodiment of the flexible direct-current power grid control method provided by the invention, and are not described herein again.
Fig. 8 is a schematic diagram of a preferred implementation of the terminal device provided by the present invention. The terminal device of this embodiment includes: a processor, a memory, and a computer program, such as a flexible direct current grid control program, stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above embodiments of the flexible dc power grid control method, such as steps S101 to S104 shown in fig. 1, are implemented. Alternatively, the processor implements the functions of the modules/units in the above device embodiments when executing the computer program.
Illustratively, the computer program may be partitioned into one or more modules/units that are stored in the memory and executed by the processor to implement the invention. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, which are used for describing the execution process of the computer program in the terminal device. For example, the computer program may be divided into a power reference value setting module, a power control module, a voltage control module and a current control module, and specific functions of each module are not described herein.
The terminal device can be a desktop computer, a notebook, a palm computer, a cloud server and other computing devices. 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 schematic diagram is merely an example of a terminal device and does not constitute a limitation of a terminal device, and may include more or less components than those shown, or combine certain components, or different components, for example, the terminal device may also include input output devices, network access devices, buses, etc.
The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component, or the like. The general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like, which is the control center of the terminal device and connects the various parts of the whole terminal device using various interfaces and lines.
The memory may be used for storing the computer programs and/or modules, and the processor may implement various functions of the terminal device by executing or executing the computer programs and/or modules stored in the memory and calling data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, a phonebook, etc.) created according to the use of the cellular phone, and the like. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.
Wherein, the terminal device integrated module/unit can be stored in a computer readable storage medium if it is implemented in the form of software functional unit and sold or used as a stand-alone product. Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.
According to the flexible direct current power grid control method, device, equipment and storage medium, the secondary frequency modulation control model is introduced, the frequency modulation and voltage regulation characteristics of the synchronous motor can be fully applied to a direct current power transmission system, the characteristics of the synchronous motor of the direct current system are further simulated, the direct current system can be more conveniently equivalent to the synchronous motor power grid, the system change can be responded in millisecond level, the reactive/active power, voltage and current of the direct current system are regulated, and the stability of the direct current system is maintained.
It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. In addition, in the drawings of the embodiment of the apparatus provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, and may be specifically implemented as one or more communication buses or signal lines. One of ordinary skill in the art can understand and implement it without inventive effort.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims (10)

1. A flexible direct current power grid control method is characterized by comprising the following steps:
acquiring a voltage measurement value and a frequency measurement value of an alternating current grid-connected point of a converter station, and outputting an active power reference value and a reactive power reference value according to the voltage measurement value, the frequency measurement value and a preset secondary frequency modulation control model;
measuring the active power and the reactive power of the grid-connected point, and outputting an alternating voltage phase angle reference value and an alternating voltage amplitude reference value of the grid-connected point according to the active power reference value, the reactive power reference value, a preset active power control model and a preset reactive power control model;
measuring the alternating voltage measured value of the grid-connected point, carrying out park transformation on the alternating voltage measured value according to the alternating voltage phase angle reference value, transforming the three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating voltage dq component value of the grid-connected point; setting a voltage reference value of an alternating voltage d component of the grid-connected point as the alternating voltage amplitude reference value, and setting a voltage reference value of an alternating voltage q component of the grid-connected point as zero; controlling the alternating voltage dq component value according to a set voltage reference value of an alternating voltage d component, a set voltage reference value of an alternating voltage q component and a preset voltage control model, and outputting a current dq component reference value;
measuring the alternating current measured value of the grid-connected point, carrying out park transformation on the alternating current measured value according to the alternating voltage phase angle reference value, transforming the three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating current dq component value of the grid-connected point; controlling the alternating current dq component value according to the current dq component reference value and a preset current control model, and outputting a valve side voltage dq component reference value of the converter station; and performing park inverse transformation on the reference value of the dq component of the valve side voltage according to the reference value of the phase angle of the alternating voltage, performing inverse transformation from a dq coordinate system to an abc coordinate system, and outputting a three-phase voltage reference wave of the converter for a control link of the converter valve.
2. The method according to claim 1, wherein the obtaining a voltage measurement value and a frequency measurement value of an ac grid-connected point of a converter station, and outputting a power reference value and a reactive power reference value according to the voltage measurement value, the frequency measurement value, and a preset secondary frequency modulation control model specifically comprises:
obtaining a voltage measurement value of an alternating current grid-connected point of a converter station to obtain an amplitude V of an alternating current power supply of the grid-connected pointmAnd the AC power frequency f of the grid-connected pointm；
Through secondary frequency modulation control model:
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and
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outputting a power reference value comprising: reference value of active power PrefAnd a reactive power reference value QrefWherein, in the step (A),
frefand VmrefRespectively a frequency nominal reference value and a voltage nominal reference value, P, of said grid-connected pointnomAnd QnomRated active power and rated reactive power, P, respectively, for the design of the main circuit of the DC systemsetAnd QsetReference value of secondary frequency modulation active power and reference value of secondary frequency modulation reactive power, T, set for a scheduling system respectivelypAnd TqRespectively an active power time constant control parameter and a reactive power time constant control parameter, sigma, for determining the secondary frequency modulation dynamic response timepAnd σqRespectively an active power secondary frequency modulation contribution factor and a reactive power secondary frequency modulation contribution factor.
3. The method according to claim 2, wherein the measuring active power and reactive power of the grid-connected point and outputting an ac voltage phase angle reference value and an ac voltage amplitude reference value of the grid-connected point according to the active power reference value, the reactive power reference value, a preset active power control model and a preset reactive power control model specifically comprises:
measuring the active power P and the reactive power Q of the grid-connected point, and according to the active reference value and the reactive power reference value; an active power control model and a reactive power control model constructed according to a synchronous generator equation of motion:
Figure 534699DEST_PATH_IMAGE003
and
Figure 809823DEST_PATH_IMAGE004
generating the AC voltage phase angle reference value Ɵ and the AC voltage amplitude reference value V of the grid-connected pointmr(ii) a Wherein the content of the first and second substances,
Jpand JqRespectively, virtual synchronous control of inertia constant, DPAnd DqRespectively an active reactive power virtual synchronous control regulating constant and a reactive power virtual synchronous control regulating constant, omegarefNominal reference value f for the frequency of the grid-connection pointrefAngular velocity of (i.e.,. omega.)ref =2πfref。
4. The flexible direct-current power grid control method according to claim 3, wherein the alternating-current voltage measured value of the grid-connected point is measured, the alternating-current voltage measured value is subjected to park transformation according to the alternating-current voltage phase angle reference value, a three-phase alternating-current electric quantity is transformed from an abc coordinate system to a dq coordinate system, and an alternating-current voltage dq component value of the grid-connected point is output; setting a voltage reference value of an alternating voltage d component of the grid-connected point as the alternating voltage amplitude reference value, and setting a voltage reference value of an alternating voltage q component of the grid-connected point as zero; controlling the value of the dq component of the alternating voltage according to a set voltage reference value of the d component of the alternating voltage, a set voltage reference value of the q component of the alternating voltage and a preset voltage control model, and outputting a reference value of the dq component of the current, specifically comprising:
by measuring the AC voltage measurement V of the point of connectionabcAccording to the phase angle reference value of the AC voltageƟMeasuring the AC voltage value VabcCarrying out park transformation, transforming the three-phase alternating current electric quantity from an abc coordinate system to a dq coordinate system to obtain an alternating voltage dq component voltage value Vdq；
Setting the reference value V of the amplitude of the AC voltagemrFor d component V of said alternating voltagedVoltage reference value VdrefSetting 0 as said component V of the AC voltage qqReference value V ofqrefI.e. Vdref=Vmr，Vqref=0；
Respectively according to d components V of the AC voltagedVoltage reference value VdrefAnd an alternating voltage q component VqVoltage reference value VqrefFor the component V of the alternating voltage dqdAnd VqControl is performed to output a reference value I of an alternating current dq componentdrefAnd Iqref。
5. The flexible direct current grid control method according to claim 4, wherein the alternating current measured value of the grid-connected point is measured, the alternating current measured value is subjected to park transformation according to the alternating voltage phase angle reference value, a three-phase alternating current capacity is transformed from an abc coordinate system to a dq coordinate system, and an alternating current dq component value of the grid-connected point is output; controlling the alternating current dq component value according to the current dq component reference value and a preset current control model, and outputting a valve side voltage dq component reference value of the converter station; according to the alternating voltage phase angle reference value, carrying out park inverse transformation on the valve side voltage dq component reference value, carrying out inverse transformation from a dq coordinate system to an abc coordinate system, and outputting a converter three-phase voltage reference wave for a converter valve control link, wherein the method specifically comprises the following steps:
by measuring the AC current measured value I of the grid-connected pointabcAccording to the phase angle reference value of the AC voltageƟThe actual value I of the three-phase alternating currentabcCarrying out park transformation, transforming the three-phase alternating current magnitude from abc coordinate system to dq coordinate system to obtain the grid-connected point alternating current dq component current value Idq；
Leading the grid-connected point alternating current dq component I to pass through a current control modeldAnd IqRespectively following the current reference values IdrefAnd IqrefGenerating a valve-side voltage dq component reference wave VcdrefAnd Vcqref；
According to the reference value of the phase angle of the AC voltageƟInverse park transformation is carried out on the valve side voltage reference wave, and inverse transformation is carried out on the dq coordinate system to the abc coordinate system to obtain a valve side three-phase voltage reference wave VcabcAnd the input quantity is used as the input quantity of the control link of the converter valve.
6. A flexible dc network control apparatus, comprising: the device comprises a power reference value setting module, a power control module, a voltage control module and a current control module;
the power reference value setting module is used for acquiring a voltage measurement value and a frequency measurement value of an alternating current grid-connected point of the converter station, and outputting an active power reference value and a reactive power reference value according to the voltage measurement value, the frequency measurement value and a preset secondary frequency modulation control model;
the power control module is used for measuring the active power and the reactive power of the grid-connected point and outputting an alternating voltage phase angle reference value and an alternating voltage amplitude reference value of the grid-connected point according to the active power reference value, the reactive power reference value, a preset active power control model and a preset reactive power control model;
the voltage control module is used for measuring an alternating voltage measured value of the grid-connected point, carrying out park transformation on the alternating voltage measured value according to the alternating voltage phase angle reference value, transforming a three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating voltage dq component value of the grid-connected point; setting a voltage reference value of an alternating voltage d component of the grid-connected point as the alternating voltage amplitude reference value, and setting a voltage reference value of an alternating voltage q component of the grid-connected point as zero; controlling the alternating voltage dq component value according to a set voltage reference value of an alternating voltage d component, a set voltage reference value of an alternating voltage q component and a preset voltage control model, and outputting a current dq component reference value;
the current control module is used for measuring an alternating current measured value of the grid-connected point, carrying out park transformation on the alternating current measured value according to the alternating voltage phase angle reference value, transforming a three-phase alternating current capacity from an abc coordinate system to a dq coordinate system, and outputting an alternating current dq component value of the grid-connected point; controlling the alternating current dq component value according to the current dq component reference value and a preset current control model, and outputting a valve side voltage dq component reference value of the converter station; and performing park inverse transformation on the reference value of the dq component of the valve side voltage according to the reference value of the phase angle of the alternating voltage, performing inverse transformation from a dq coordinate system to an abc coordinate system, and outputting a three-phase voltage reference wave of the converter for a control link of the converter valve.
7. The flexible direct current network control device according to claim 6, wherein the power reference value setting module is specifically configured to:
obtaining a voltage measurement value of an alternating current grid-connected point of a converter station to obtain an amplitude V of an alternating current power supply of the grid-connected pointmAnd the AC power frequency f of the grid-connected pointm；
Through secondary frequency modulation control model:
Figure 390977DEST_PATH_IMAGE005
and
Figure 100045DEST_PATH_IMAGE006
outputting a power reference value comprising: reference value of active power PrefAnd a reactive power reference value QrefWherein, in the step (A),
frefand VmrefRespectively a frequency nominal reference value and a voltage nominal reference value, P, of said grid-connected pointnomAnd QnomRated active power and rated reactive power, P, respectively, for the design of the main circuit of the DC systemsetAnd QsetReference value of secondary frequency modulation active power and reference value of secondary frequency modulation reactive power, T, set for a scheduling system respectivelypAnd TqRespectively an active power time constant control parameter and a reactive power time constant control parameter, sigma, for determining the secondary frequency modulation dynamic response timepAnd σqRespectively an active power secondary frequency modulation contribution factor and a reactive power secondary frequency modulation contribution factor.
8. The flexible direct current network control apparatus according to claim 6, wherein the power control module is specifically configured to:
measuring the active power P of the grid-connected point andthe reactive power Q is obtained according to the active reference value and the reactive power reference value; an active power control model and a reactive power control model constructed according to a synchronous generator equation of motion:
Figure 766650DEST_PATH_IMAGE007
and
Figure 845464DEST_PATH_IMAGE008
generating the AC voltage phase angle reference value of the grid-connected pointƟAnd the reference value V of the amplitude of the alternating voltagemr(ii) a Wherein the content of the first and second substances,
Jpand JqRespectively, virtual synchronous control of inertia constant, DPAnd DqRespectively an active reactive power virtual synchronous control regulating constant and a reactive power virtual synchronous control regulating constant, omegarefNominal reference value f for the frequency of the grid-connection pointrefAngular velocity of (i.e.,. omega.)ref =2πfref。
9. A terminal device, characterized by comprising a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, the processor implementing the flexible direct current power grid control method according to any one of claims 1 to 5 when executing the computer program.
10. A computer-readable storage medium, comprising a stored computer program, wherein when the computer program runs, the computer-readable storage medium controls an apparatus to execute the flexible direct current power grid control method according to any one of claims 1 to 5.
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CN113765122A (en) * 2021-08-04 2021-12-07 广东安朴电力技术有限公司 MMC converter valve control method and control system

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