WO2022267317A1 - 基于电网构造型的柔性直流孤岛控制方法、装置及介质 - Google Patents

基于电网构造型的柔性直流孤岛控制方法、装置及介质 Download PDF

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WO2022267317A1
WO2022267317A1 PCT/CN2021/131700 CN2021131700W WO2022267317A1 WO 2022267317 A1 WO2022267317 A1 WO 2022267317A1 CN 2021131700 W CN2021131700 W CN 2021131700W WO 2022267317 A1 WO2022267317 A1 WO 2022267317A1
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Prior art keywords
voltage
grid
reference value
frequency
connected point
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PCT/CN2021/131700
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English (en)
French (fr)
Inventor
陈怡静
黄伟煌
蔡东晓
彭发喜
李岩
赵晓斌
许树楷
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南方电网科学研究院有限责任公司
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Publication of WO2022267317A1 publication Critical patent/WO2022267317A1/zh

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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
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/388—Islanding, i.e. disconnection of local power supply from the network
    • 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
    • H02J3/36—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
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • H02J2003/365—Reducing harmonics or oscillations in HVDC
    • 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]

Definitions

  • the invention relates to the technical field of power electronic control, in particular to a flexible DC island control method, device and medium based on grid configuration.
  • the engineering control method of flexible DC transmission system is mainly based on the voltage phase locked loop (PLL) constant active/reactive power-current inner and outer loop vector control method.
  • PLL voltage phase locked loop
  • the AC power grid connected to the HVDC transmission system under the grid control strategy is switched from the grid-connected type to the island grid, if the DC system still operates under the grid-type control strategy without special control means, Then its AC frequency will shift, and the degree of shift is related to the transmission power level of the DC system before and after the grid switching. If the power level difference is small, the frequency deviation is small; if the power level difference before and after the DC system switching is large, the frequency deviation is large, and the frequency deviation exceeds the allowable operating range, which will directly affect the safety of the DC system operation. sex and stability.
  • Embodiments of the present invention provide a flexible DC island control method, device, and medium based on grid configuration, which can avoid continuous use of grid-type control strategies, causing the frequency of the grid-connected point to exceed the extreme operating frequency, causing the DC system to stop running, resulting in system failure unstable.
  • An embodiment of the present invention provides a flexible DC island control method based on grid configuration, characterized in that the method includes:
  • the flexible direct current transmission system After the flexible direct current transmission system is connected to the power grid topology and is only connected to the island type power grid and the direct current system, detect the grid connection point frequency of the grid connection point of the flexible direct current transmission system;
  • an AC voltage phase angle reference value is output according to a preset rated frequency reference value, and the flexible direct current transmission system is implemented according to the AC voltage phase angle reference value and a steady-state control method power control, voltage control and current control.
  • the method also includes:
  • the power control, voltage control and current control of the flexible direct current transmission system are performed according to the steady state control method of the flexible direct current transmission system.
  • the AC voltage phase angle reference value is output according to the preset rated frequency reference value, and the AC voltage phase angle reference value and the steady-state control method are used to perform the The power control, voltage control and current control of the flexible DC transmission system are described, including:
  • f exmin is the lower limit of the extreme operating frequency of the grid-connected point and f exmax are the upper limit of the extreme operating frequency of the grid-connected point, and f min and f max are the minimum frequency and maximum frequency of the long-term operation of the grid-connected point, respectively;
  • Integral operation is performed according to the preset rated frequency reference value f ref to obtain the AC voltage phase angle reference value;
  • Measure the AC voltage measurement value of the grid-connected point perform Parker transformation on the AC voltage measurement value according to the AC voltage phase angle reference value ⁇ , transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the The AC voltage dq component value of the grid-connected point;
  • the voltage reference value of the AC voltage d component of the grid-connected point is set as the AC voltage amplitude reference value, and the voltage reference value of the AC voltage q component of the grid-connected point is set is zero;
  • the set voltage reference value of the AC voltage d component, the set voltage reference value of the AC voltage q component and the preset voltage control model the value of the AC voltage dq component is controlled, and the current dq component is output Reference;
  • Measure the AC current measurement value of the grid-connected point perform Parker transformation on the AC current measurement value according to the AC voltage phase angle reference value, transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the AC current dq component value at the grid-connected point; control the AC current dq component value according to the current dq component reference value and the preset current control model, and output the valve side voltage dq component reference value of the converter station; according to The phase angle reference value of the AC voltage performs Parker inverse transformation on the dq component reference value of the valve side voltage, inversely transforms from the dq coordinate system to the abc coordinate system, and outputs the converter three-phase voltage reference wave for converter valve control links.
  • the power control, voltage control and current control of the flexible direct current transmission system are performed according to the steady state control method of the flexible direct current transmission system, specifically including:
  • Measure the AC voltage measurement value of the grid-connected point perform Parker transformation on the AC voltage measurement value according to the AC voltage phase angle reference value ⁇ , transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the The AC voltage dq component value of the grid-connected point;
  • the voltage reference value of the AC voltage d component of the grid-connected point is set as the AC voltage amplitude reference value, and the voltage reference value of the AC voltage q component of the grid-connected point is set is zero;
  • the set voltage reference value of the AC voltage d component, the set voltage reference value of the AC voltage q component and the preset voltage control model the value of the AC voltage dq component is controlled, and the current dq component is output Reference;
  • Measure the AC current measurement value of the grid-connected point perform Parker transformation on the AC current measurement value according to the AC voltage phase angle reference value, transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the AC current dq component value at the grid-connected point; control the AC current dq component value according to the current dq component reference value and the preset current control model, and output the valve side voltage dq component reference value of the converter station; according to The phase angle reference value of the AC voltage performs Parker inverse transformation on the dq component reference value of the valve side voltage, inversely transforms from the dq coordinate system to the abc coordinate system, and outputs the converter three-phase voltage reference wave for converter valve control link.
  • Another embodiment of the present invention provides a grid-based flexible DC island control device, including: a frequency detection module and a first control module;
  • the frequency detection module is used to detect the grid-connected point frequency of the grid-connected point of the flexible DC power transmission system after the topology structure of the flexible DC transmission system is changed to only the island-type grid connected to the DC system;
  • the first control module is used to output an AC voltage phase angle reference value according to a preset rated frequency reference value when the frequency of the grid-connected point fluctuates to an extreme frequency range, and according to the AC voltage phase angle reference value and steady-state control
  • the method performs power control, voltage control and current control of the flexible direct current transmission system.
  • the device further includes a second control module
  • the second control module is used to perform power control, voltage control and current control of the flexible direct current transmission system according to the steady-state control method of the flexible direct current transmission system when the frequency fluctuation of the grid-connected point operates within a stable range.
  • the first control module is specifically used for:
  • f exmin is the lower limit of the extreme operating frequency of the grid-connected point and f exmax are the upper limit of the extreme operating frequency of the grid-connected point, and f min and f max are the minimum frequency and maximum frequency of the long-term operation of the grid-connected point, respectively;
  • Integral operation is performed according to the preset rated frequency reference value f ref to obtain the AC voltage phase angle reference value;
  • Measure the AC voltage measurement value of the grid-connected point perform Parker transformation on the AC voltage measurement value according to the AC voltage phase angle reference value ⁇ , transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the The AC voltage dq component value of the grid-connected point;
  • the voltage reference value of the AC voltage d component of the grid-connected point is set as the AC voltage amplitude reference value, and the voltage reference value of the AC voltage q component of the grid-connected point is set is zero;
  • the set voltage reference value of the AC voltage d component, the set voltage reference value of the AC voltage q component and the preset voltage control model the value of the AC voltage dq component is controlled, and the current dq component is output Reference;
  • Measure the AC current measurement value of the grid-connected point perform Parker transformation on the AC current measurement value according to the AC voltage phase angle reference value, transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the AC current dq component value at the grid-connected point; control the AC current dq component value according to the current dq component reference value and the preset current control model, and output the valve side voltage dq component reference value of the converter station; according to The phase angle reference value of the AC voltage performs Parker inverse transformation on the dq component reference value of the valve side voltage, inversely transforms from the dq coordinate system to the abc coordinate system, and outputs the converter three-phase voltage reference wave for converter valve control link.
  • the power control, voltage control and current control of the flexible direct current transmission system are performed according to the steady state control method of the flexible direct current transmission system, specifically including:
  • Measure the AC voltage measurement value of the grid-connected point perform Parker transformation on the AC voltage measurement value according to the AC voltage phase angle reference value ⁇ , transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the The AC voltage dq component value of the grid-connected point;
  • the voltage reference value of the AC voltage d component of the grid-connected point is set as the AC voltage amplitude reference value, and the voltage reference value of the AC voltage q component of the grid-connected point is set is zero;
  • the set voltage reference value of the AC voltage d component, the set voltage reference value of the AC voltage q component and the preset voltage control model the value of the AC voltage dq component is controlled, and the current dq component is output Reference;
  • Measure the AC current measurement value of the grid-connected point perform Parker transformation on the AC current measurement value according to the AC voltage phase angle reference value, transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the AC current dq component value at the grid-connected point; control the AC current dq component value according to the current dq component reference value and the preset current control model, and output the valve side voltage dq component reference value of the converter station; according to The phase angle reference value of the AC voltage performs Parker inverse transformation on the dq component reference value of the valve side voltage, inversely transforms from the dq coordinate system to the abc coordinate system, and outputs the converter three-phase voltage reference wave for converter valve control links.
  • An embodiment of the present invention also provides a flexible DC island control device based on grid configuration, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, and the processor executes The computer program implements the grid configuration-based flexible DC island control method described in any one of the above embodiments.
  • An embodiment of the present invention also provides a computer-readable storage medium, the computer-readable storage medium includes a stored computer program, wherein, when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the above-mentioned embodiments A flexible DC island control method based on grid configuration described in any one of the above.
  • the present invention provides a flexible DC island control method, device, and medium based on grid configuration.
  • the topological structure of the AC grid connected to the flexible DC transmission system is composed of
  • the frequency of the grid-connected point of the flexible DC power transmission system is detected; when the frequency of the grid-connected point fluctuates to an extreme frequency range, the AC voltage is output according to the preset rated frequency reference value Phase angle reference value, according to the AC voltage phase angle reference value and the steady-state control method, the power control, voltage control and current control of the flexible direct current transmission system are performed;
  • the network-type control strategy continues to be adopted, causing the frequency of the grid-connected point to exceed the extreme operating frequency, causing the DC system to stop running, resulting in system instability, and improving the stability of the system control process.
  • Fig. 1 is a schematic flow diagram of a flexible DC island control method based on grid configuration provided by an embodiment of the present invention
  • Fig. 2 is a schematic structural diagram of an AC voltage phase angle reference value acquisition model of a flexible DC island control method based on grid configuration provided by an embodiment of the present invention
  • Fig. 3 is a frame diagram of active power reference value generated by a secondary frequency modulation control model provided by an embodiment of the present invention
  • Fig. 4 is a frame diagram of a reactive power reference value generated by a secondary frequency modulation control model provided by an embodiment of the present invention
  • Fig. 5 is a control frame diagram of a power control model provided by an embodiment of the present invention.
  • Fig. 6 is a control frame diagram of a voltage control model provided by an embodiment of the present invention.
  • Fig. 7 is a control frame diagram of a current control model provided by an embodiment of the present invention.
  • Fig. 8 is a schematic structural diagram of a grid-based flexible DC island control device provided by an embodiment of the present invention.
  • Fig. 9 is a schematic structural diagram of a grid-based flexible DC island control device according to yet another embodiment of the present invention.
  • FIG. 1 is a schematic flowchart of a grid configuration-based flexible DC island control method provided by an embodiment of the present invention, including step S101 ⁇ S102:
  • the frequency of the grid-connection point fluctuates to an extreme frequency range
  • the frequency of the grid-connection point will gradually deviate from the stable range.
  • the frequency of the grid-connection point exceeds the extreme operating frequency , will cause the DC system to stop running.
  • output the AC voltage phase angle reference value according to the preset rated frequency reference value and perform voltage control and current control of the flexible DC power transmission system;
  • the embodiment of the present invention provides a flexible DC island control method based on grid structure.
  • the topological structure of the flexible DC transmission system connected to the grid is changed to only the island grid connected to the DC system.
  • detect the grid-connected point frequency of the grid-connected point of the flexible direct current transmission system when the frequency of the grid-connected point fluctuates to an extreme frequency range, output the AC voltage phase angle reference value according to the preset frequency rated reference value, and output the AC voltage phase angle reference value according to the AC
  • the voltage phase angle reference value and the steady-state control method are used to perform the power control, voltage control and current control of the flexible direct current transmission system; in order to avoid the use of a network-structured control strategy, after the frequency of the grid-connected point deviates from the stable range, continue to use the structure
  • the grid-type control strategy causes the frequency of the grid-connected point to exceed the extreme operating frequency, causing the DC system to stop running, resulting in system instability, and improving the stability of the system control process.
  • the method further includes step S103:
  • the power control, voltage control and current control of the flexible direct current transmission system are performed according to the steady state control method of the flexible direct current transmission system.
  • the flexible direct current transmission system when the flexible direct current transmission system is connected to the power grid and changes from the grid-connected type to the island type, if the power change caused by the state change before and after the connection to the power grid is small, causing the frequency shift of the grid-connected point, the parallel If the network point frequency is within a stable range, the flexible direct current transmission system can still operate in a steady state. In this case, the frequency provided by the direct current system remains within a stable range and is controlled according to the steady state control method of the flexible direct current transmission system The flexible direct current transmission system.
  • the flexible direct current transmission system When the flexible direct current transmission system is switched from the interconnected type to the island type, when the grid-connected point frequency remains within a stable range, the flexible direct current transmission system is controlled according to the steady-state control method of the flexible direct current transmission system to realize the control of the flexible direct current transmission system stability control.
  • step S102 specifically includes:
  • f exmin is the lower limit of the extreme operating frequency of the grid-connected point and f exmax are the upper limit of the extreme operating frequency of the grid-connected point, and f min and f max are the minimum frequency and maximum frequency of the long-term operation of the grid-connected point, respectively;
  • Integral operation is performed according to the preset rated frequency reference value f ref to obtain the AC voltage phase angle reference value;
  • Measure the AC voltage measurement value of the grid-connected point perform Parker transformation on the AC voltage measurement value according to the AC voltage phase angle reference value ⁇ , transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the The AC voltage dq component value of the grid-connected point;
  • the voltage reference value of the AC voltage d component of the grid-connected point is set as the AC voltage amplitude reference value, and the voltage reference value of the AC voltage q component of the grid-connected point is set is zero;
  • the set voltage reference value of the AC voltage d component, the set voltage reference value of the AC voltage q component and the preset voltage control model the value of the AC voltage dq component is controlled, and the current dq component is output Reference;
  • Measure the AC current measurement value of the grid-connected point perform Parker transformation on the AC current measurement value according to the AC voltage phase angle reference value, transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the AC current dq component value at the grid-connected point; control the AC current dq component value according to the current dq component reference value and the preset current control model, and output the valve side voltage dq component reference value of the converter station; according to The phase angle reference value of the AC voltage performs Parker inverse transformation on the dq component reference value of the valve side voltage, inversely transforms from the dq coordinate system to the abc coordinate system, and outputs the converter three-phase voltage reference wave for converter valve control link.
  • the frequency of the grid-connected point is detected in real time and judged.
  • the grid-connected point is determined Frequency operation to the extreme frequency range, where f exmin is the lower limit of the extreme operating frequency of the grid-connected point and f exmax the upper limit of the extreme operating frequency of the grid-connected point, and f min and f max are the minimum frequency and maximum frequency of the long-term operation of the grid-connected point respectively;
  • FIG. 2 it is a schematic structural diagram of an AC voltage phase angle reference value acquisition model of a flexible DC island control method based on grid configuration provided by an embodiment of the present invention
  • Output power reference value including: active power reference value P ref and reactive power reference value Q ref , wherein,
  • f ref and V mref are the rated frequency reference value and voltage rated reference value of the grid-connected point, respectively
  • P nom and Q nom are the rated active power and rated reactive power in the design of the main circuit of the DC system, respectively
  • P set and Q set are respectively
  • T p and T q are respectively the active power time constant control parameters and reactive power that determine the dynamic response time of the secondary frequency modulation Time constant control parameters
  • ⁇ p and ⁇ q are contribution factors of active power secondary frequency modulation and reactive power secondary frequency modulation contribution factors, respectively.
  • the AC voltage measurement value V abc is subjected to Parker transformation according to the AC voltage phase angle reference value ⁇ , and the three-phase AC electrical quantity is transformed from the abc coordinate system to the dq coordinate system Obtain the AC voltage dq component voltage value V dq ;
  • the AC voltage amplitude reference value V mref is set as the voltage reference value V dref of the AC voltage d component V d
  • the AC voltage dq components V d and V q are controlled respectively according to the voltage reference value V dref of the AC voltage d component V d and the voltage reference value V qref of the AC voltage q component V q , and the output of the AC current dq component is Reference values I dref and I qref .
  • the actual value I abc of the three-phase AC current is subjected to Parker transformation according to the AC voltage phase angle reference value ⁇ , and the three-phase AC electrical quantity is transformed from the abc coordinate system to dq
  • the coordinate system obtains the current value I dq of the alternating current dq component of the grid-connected point;
  • the AC current dq components I d and I q of the grid-connected point follow the current reference values I dref and I qref respectively , and generate valve-side voltage dq component reference waves V cdref and V cqref ;
  • valve-side voltage reference wave is inversely transformed by Parker, and the valve-side three-phase voltage reference wave V cabc is obtained from the dq coordinate system to the abc coordinate system as the input of the converter valve control link. quantity.
  • the grid-connected control strategy continues to be used, causing the frequency of the grid-connected point to exceed the extreme operating frequency, causing the DC system to stop running, resulting in system instability , which improves the stability of the system control process.
  • step S103 specifically includes:
  • Measure the AC voltage measurement value of the grid-connected point perform Parker transformation on the AC voltage measurement value according to the AC voltage phase angle reference value ⁇ , transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the The AC voltage dq component value of the grid-connected point;
  • the voltage reference value of the AC voltage d component of the grid-connected point is set as the AC voltage amplitude reference value, and the voltage reference value of the AC voltage q component of the grid-connected point is set is zero;
  • the set voltage reference value of the AC voltage d component, the set voltage reference value of the AC voltage q component and the preset voltage control model the value of the AC voltage dq component is controlled, and the current dq component is output Reference;
  • Measure the AC current measurement value of the grid-connected point perform Parker transformation on the AC current measurement value according to the AC voltage phase angle reference value, transform the three-phase AC electrical quantity from the abc coordinate system to the dq coordinate system, and output the AC current dq component value at the grid-connected point; control the AC current dq component value according to the current dq component reference value and the preset current control model, and output the valve side voltage dq component reference value of the converter station; according to The phase angle reference value of the AC voltage performs Parker inverse transformation on the dq component reference value of the valve side voltage, inversely transforms from the dq coordinate system to the abc coordinate system, and outputs the converter three-phase voltage reference wave for converter valve control link.
  • the flexible direct current transmission system is controlled according to the steady state control method of the flexible direct current transmission system.
  • the specific process is as follows:
  • the power reference value includes active power reference value P ref and reactive power reference value Q ref ; in addition, the parameter information of the electric power system obtained in advance is included in the described secondary frequency modulation control model, specifically: f ref and V mref is the rated frequency reference value and voltage rated reference value of the grid-connected point, respectively, P nom and Q nom are the rated active power and rated reactive power in the design of the main circuit of the DC system, respectively, and P set and Q set are the dispatching system
  • the reference value of the active power of the secondary frequency modulation and the reference value of the reactive power of the secondary frequency modulation are set, T p and T q are respectively the active power time constant control parameters and the reactive power time constant control parameters that determine the dynamic response time of the secondary frequency modulation Parameters, ⁇ p and ⁇ q are contribution factors of secondary frequency modulation of active power and contribution factors of secondary frequency modulation of reactive power, respectively.
  • FIG. 3 it is a frame diagram of the active power reference value generated by the secondary frequency modulation control model provided by the embodiment of the present invention.
  • the reference value P set of the secondary frequency modulation active power set by the dispatching system, the secondary frequency modulation control model is based on the frequency rated reference value f ref , the rated active power P nom in the design of the main circuit of the DC system, and the contribution of the active power secondary frequency modulation Factor ⁇ p , and active power time constant control parameter T p , output active power reference value P ref ;
  • FIG. 4 it is a frame diagram of a reactive power reference value generated by a secondary frequency modulation control model provided by an embodiment of the present invention.
  • the secondary frequency modulation control model is based on the voltage rated reference value V mref , the rated reactive power Q nom of the DC system main circuit design, and the reactive power Contribution factor ⁇ q of secondary frequency modulation, and reactive power time constant control parameter T q , output reactive power reference value Q ref ;
  • the power reference value generated by the secondary frequency modulation control model is a quasi-steady-state control link, and its dynamic response time accuracy is at the second level. After the voltage or frequency of the grid-connected point deviates, it can be reduced by the generated active/reactive power reference value. The degree of deviation between the frequency amplitude and the voltage amplitude.
  • the output voltage reference value includes the AC voltage phase angle reference value ⁇ and the AC voltage amplitude reference value V mref ;
  • P is the measured active power voltage value
  • Q is the measured reactive power voltage value
  • ⁇ is the phase angle at which the DC system is connected to the power grid
  • f is the frequency of the connected power grid
  • J p and J q are respectively Virtual synchronous control inertia constants
  • D P and D q are active/reactive power virtual synchronous control adjustment constants
  • active power voltage value P active power reference value P ref
  • the working principle is basically similar to that of the active power, and will not be repeated here.
  • FIG. 5 it is a control frame diagram of a power control model provided by an embodiment of the present invention, input active power voltage value P, active power reference value P ref , reactive power voltage value Q, and reactive power reference value Q ref , through the process shown in the figure, it can complete the stabilization of active/reactive power voltage and output voltage reference value ⁇ and V mref ;
  • the precision of the response of the power control model is millisecond level, corresponding to the primary frequency modulation link of synchronous motor control.
  • the power control link simulates the motion equation of the synchronous generator, and constructs the amplitude and phase angle of the grid-side grid-connected point voltage through power control, so that the flexible DC system has the self-synchronization function and the ability of rapid frequency regulation and voltage regulation.
  • the control link No phase-locked loop is required.
  • FIG. 6 it is a control frame diagram of a voltage control model provided by an embodiment of the present invention, and the actual AC voltage dq component V of the grid-connected point is calculated according to the reference values V dref and V qref of the AC voltage dq component of the grid-connected point respectively. d and V q are controlled, and the reference values I dref and I qref of the AC current dq component of the grid-connected point are output. .
  • FIG. 7 it is a control frame diagram of a current control model provided by an embodiment of the present invention.
  • the AC current dq components I d and I q of the grid-connected point follow the current reference values I dref and I qref respectively , and generate valve-side voltage dq component reference waves V cdref and V cqref ;
  • the valve-side voltage reference wave is subjected to Parker inverse transformation, and the valve-side three-phase voltage reference wave V cabc is obtained from the dq coordinate system to the abc coordinate system, which is used as the input quantity of the converter valve control link.
  • the frequency modulation and voltage regulation characteristics of the synchronous motor can be fully applied to the DC transmission system, and the characteristics of the synchronous motor of the DC system can be further simulated, and the DC system can be more conveniently equivalent to the synchronous motor grid. Respond to system changes in milliseconds, adjust the reactive/active power, voltage, and current of the DC system, and maintain the stability of the DC system.
  • the embodiment of the present invention provides a flexible DC island control method based on grid structure.
  • the topological structure of the flexible DC transmission system connected to the grid is changed to only the island grid connected to the DC system.
  • detect the grid-connected point frequency of the grid-connected point of the flexible direct current transmission system when the frequency of the grid-connected point fluctuates to an extreme frequency range, output the AC voltage phase angle reference value according to the preset frequency rated reference value, and output the AC voltage phase angle reference value according to the AC
  • the voltage phase angle reference value and the steady-state control method are used to perform the power control, voltage control and current control of the flexible direct current transmission system; in order to avoid the use of a network-structured control strategy, after the frequency of the grid-connected point deviates from the stable range, continue to use the structure
  • the grid-type control strategy causes the frequency of the grid-connected point to exceed the extreme operating frequency, causing the DC system to stop running, resulting in system instability, and improving the stability of the system control process.
  • the embodiment of the present invention also provides a flexible DC island control device based on grid configuration, see Fig. 8, which is a schematic structural diagram of a flexible DC island control device based on grid configuration provided by an embodiment of the present invention, the device includes a frequency detection module and a first control module;
  • the frequency detection module is used to detect the grid-connected point frequency of the grid-connected point of the flexible DC power transmission system after the topology structure of the flexible DC transmission system is changed to only the island-type grid connected to the DC system;
  • the first control module is used to output an AC voltage phase angle reference value according to a preset rated frequency reference value when the frequency of the grid-connected point fluctuates to an extreme frequency range, and according to the AC voltage phase angle reference value and steady-state control
  • the method performs power control, voltage control and current control of the flexible direct current transmission system.
  • FIG. 9 it is a schematic structural diagram of a grid-based flexible DC island control device according to yet another embodiment of the present invention.
  • the flexible DC island control device based on grid configuration in this embodiment includes: a processor, a memory, and a computer program stored in the memory and operable on the processor, such as a flexible DC island control based on grid configuration program.
  • the processor executes the computer program, it realizes the steps in the above-mentioned embodiments of the grid-based flexible DC island control method, such as steps S101-S103 shown in Fig. 1 .
  • the processor executes the computer program, the functions of the modules/units in the above device embodiments are implemented.
  • the computer program can be divided into one or more modules/units, and the one or more modules/units are stored in the memory and executed by the processor to complete the present invention.
  • the one or more modules/units may be a series of computer program instruction segments capable of accomplishing specific functions, and the instruction segments are used to describe the execution process of the computer program in the grid-based flexible DC island control device .
  • the computer program can be divided into a power reference value setting module, a power control module, a voltage control module and a current control module, and the specific functions of each module will not be repeated here.
  • the grid-based flexible DC island control device may be computing devices such as desktop computers, notebooks, palmtop computers, and cloud servers.
  • the grid-based flexible DC island control device may include, but not limited to, a processor and a memory.
  • Those skilled in the art can understand that the schematic diagram is only an example of a flexible DC island control device based on a grid configuration, and does not constitute a limitation on the flexible DC island control device based on a grid configuration. Fewer components, or a combination of certain components, or different components, for example, the grid-based flexible DC island control device may also include input and output devices, network access devices, buses, and the like.
  • the so-called processor can be a central processing unit (Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), on-site Programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
  • the general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc., and the processor is the control center of the flexible DC island control device based on grid configuration, and is connected by various interfaces and lines Various parts of the entire grid-based flexible DC island control device.
  • the memory can be used to store the computer programs and/or modules, and the processor implements the computer program and/or modules stored in the memory and calls the data stored in the memory to realize the Various functions of grid-configured flexible DC island control devices.
  • the memory may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, at least one application program required by a function (such as a sound playback function, an image playback function, etc.) and the like; the storage data area may store Data created based on the use of the mobile phone (such as audio data, phonebook, etc.), etc.
  • the memory can include high-speed random access memory, and can also include non-volatile memory, such as hard disk, internal memory, plug-in hard disk, smart memory card (Smart Media Card, SMC), secure digital (Secure Digital, SD) card , flash card (Flash Card), at least one magnetic disk storage device, flash memory device, or other volatile solid-state storage device.
  • non-volatile memory such as hard disk, internal memory, plug-in hard disk, smart memory card (Smart Media Card, SMC), secure digital (Secure Digital, SD) card , flash card (Flash Card), at least one magnetic disk storage device, flash memory device, or other volatile solid-state storage device.
  • the integrated modules/units of the grid-based flexible DC island control device are realized in the form of software function units and sold or used as independent products, they can be stored in a computer-readable storage medium.
  • the present invention realizes all or part of the processes in the methods of the above embodiments, and can also be completed by instructing related hardware through a computer program.
  • the computer program can be stored in a computer-readable storage medium, and the computer When the program is executed by the processor, the steps in the above-mentioned various method embodiments can be realized.
  • the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file or some intermediate form.
  • the computer-readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a removable hard disk, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM, Read-Only Memory) , Random Access Memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal and software distribution medium, etc.
  • ROM Read-Only Memory
  • RAM Random Access Memory
  • electrical carrier signal telecommunication signal and software distribution medium, etc.
  • the flexible DC island control method, device and medium based on the grid structure provided by the present invention under the framework of the network-based control system of the flexible DC power transmission system, the topological structure of the AC power grid connected to the flexible DC power transmission system is changed from a networked type to only After the island-type power grid is connected to the DC system, the frequency of the grid-connected point of the flexible DC transmission system is detected; when the frequency of the grid-connected point fluctuates to an extreme frequency range, the AC voltage phase angle reference value is output according to the preset rated frequency reference value, Perform the power control, voltage control and current control of the flexible direct current transmission system according to the reference value of the AC voltage phase angle and the steady-state control method; in order to avoid the use of a network-type control strategy, after the frequency of the grid-connected point deviates from the stable range , continue to adopt the grid-type control strategy, causing the frequency of the grid-connected point to exceed the extreme operating frequency, causing the DC system to stop running, resulting in system instability, and improving the stability of the system control
  • the device embodiments described above are only illustrative, and the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physically separated.
  • a unit can be located in one place, or it can be distributed to multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.
  • the connection relationship between the modules indicates that they have a communication connection, which can be specifically implemented as one or more communication buses or signal lines. It can be understood and implemented by those skilled in the art without creative effort.

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Abstract

本发明公开了基于电网构造型的柔性直流孤岛控制方法、装置及介质，在柔性直流输电系统在构网型控制系统框架下，柔性直流输电系统接入的交流电网拓扑结构由联网型改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点频率；当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制；为避免采用构网型控制策略时，所述并网点频率偏离稳定范围后，继续采用构网型控制策略，导致所述并网点频率超出极端运行频率，使得直流系统停止运行，造成的系统不稳定，提高了系统控制过程的稳定性。

Description

基于电网构造型的柔性直流孤岛控制方法、装置及介质 技术领域
本发明涉及电力电子控制技术领域，尤其涉及基于电网构造型的柔性直流孤岛控制方法、装置及介质。
背景技术
随着系统中大容量电力电子设备所占比例的不断提高，电网面临全新的演化模式，以同步机为主导的传统稳定问题将演变为以电力电子设备控制为主导的新型稳定问题。
目前柔性直流输电系统工程化控制方法主要为基于电压锁相(phase locked loop，PLL)的定有功/无功-电流内外环矢量控制方法。在该控制方法下，当直流输电系统在构网型控制策略下所连接的交流电网由联网型切为孤岛型电网时，若直流系统不采取特殊控制手段仍在构网型控制策略下运行，则其交流频率会产生偏移，偏移程度与电网切换前后直流系统传输功率水平相关。若功率水平差异较小，则频率偏移程度较小；若直流系统切换前后功率水平差异较大，则频率偏移程度较大，频率偏移超出允许的运行范围会直接影响直流系统运行的安全性与稳定性。
发明内容
本发明实施例提供基于电网构造型的柔性直流孤岛控制方法、装置及介质，能够避免持续采用构网型控制策略，导致所述并网点频率超出极端运行频率，使得直流系统停止运行，造成的系统不稳定。
本发明实施例提供一种基于电网构造型的柔性直流孤岛控制方法，其特征在于，所述方法包括：
柔性直流输电系统接入电网拓扑结构改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点的并网点频率；
当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制。
优选地，所述方法还包括：
当所述并网点频率波动在稳定范围内运行时，按照柔性直流输电系统的稳态控制方法进行 所述柔性直流输电系统的功率控制、电压控制和电流控制。
优选地，所述当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制，具体包括：
当所述并网点频率f满足f exmin<f<f min或f max<f<f exmax时，判定所述并网点频率运行至极端频率范围，其中，f exmin为所述并网点极端运行频率下限和f exmax并网点极端运行频率上限，f min和f max分别为所述并网点长期运行的最小频率及最大频率；
根据预设的频率额定参考值f ref进行积分运算，得到交流电压相位角参考值；
获取换流站交流并网点的电压测量值和频率测量值，并根据所述电压测量值、所述频率测量值和预设的二次调频控制模型，输出有功功率参考值及无功功率参考值；
测量所述并网点的有功功率及无功功率，并根据所述有功功率参考值、所述无功功率参考值、预设的有功功率控制模型及预设的无功功率控制模型，输出交流电压幅值参考值；
测量所述并网点的交流电压测量值，根据所述交流电压相位角参考值θ对所述交流电压测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电压dq分量值；设定所述并网点的交流电压d分量的电压参考值为所述交流电压幅值参考值，设定所述并网点的交流电压q分量的电压参考值为零；根据设定的交流电压d分量的电压参考值、设定的交流电压q分量的电压参考值和预设的电压控制模型对所述交流电压dq分量值进行控制，并输出电流dq分量参考值；
测量所述并网点的交流电流测量值，根据所述交流电压相位角参考值对所述交流电流测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电流dq分量值；根据所述电流dq分量参考值和预设的电流控制模型对所述交流电流dq分量值进行控制，并输出换流站的阀侧电压dq分量参考值；根据所述交流电压相位角参考值对所述阀侧电压dq分量参考值进行帕克逆变换，从dq坐标系逆变换到abc坐标系，输出换流器三相电压参考波用于换流器阀控制环节。
优选地，所述当所述并网点频率波动在稳定范围内运行时，按照柔性直流输电系统的稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制，具体包括：
当所述并网点频率f满足f min<f<f max时，判定所述并网点频率运行在稳定范围内，其中，f min和f max分别为并网点长期运行的最小频率及最大频率；
获取换流站交流并网点的电压测量值和频率测量值，并根据所述电压测量值、所述频率测量值和预设的二次调频控制模型，输出有功功率参考值及无功功率参考值；
测量所述并网点的有功功率及无功功率，并根据所述有功功率参考值、所述无功功率参考值、预设的有功功率控制模型及预设的无功功率控制模型，输出所述并网点的交流电压相位角参考值及交流电压幅值参考值；
测量所述并网点的交流电压测量值，根据所述交流电压相位角参考值θ对所述交流电压测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电压dq分量值；设定所述并网点的交流电压d分量的电压参考值为所述交流电压幅值参考值，设定所述并网点的交流电压q分量的电压参考值为零；根据设定的交流电压d分量的电压参考值、设定的交流电压q分量的电压参考值和预设的电压控制模型对所述交流电压dq分量值进行控制，并输出电流dq分量参考值；
测量所述并网点的交流电流测量值，根据所述交流电压相位角参考值对所述交流电流测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电流dq分量值；根据所述电流dq分量参考值和预设的电流控制模型对所述交流电流dq分量值进行控制，并输出换流站的阀侧电压dq分量参考值；根据所述交流电压相位角参考值对所述阀侧电压dq分量参考值进行帕克逆变换，从dq坐标系逆变换到abc坐标系，输出换流器三相电压参考波用于换流器阀控制环节。
本发明另一实施例提供一种基于电网构造型的柔性直流孤岛控制装置，包括：频率检测模块和第一控制模块；
所述频率检测模块用于柔性直流输电系统接入电网拓扑结构改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点的并网点频率；
所述第一控制模块用于当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制。
作为一种优选实施方式，所述装置还包括第二控制模块；
所述第二控制模块用于当所述并网点频率波动在稳定范围内运行时，按照柔性直流输电系统的稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制。
作为一种优选实施方式，所述第一控制模块具体用于：
当所述并网点频率f满足f exmin<f<f min或f max<f<f exmax时，判定所述并网点频率运行至极端频率范围，其中，f exmin为所述并网点极端运行频率下限和f exmax并网点极端运行频率上限，f min和f max分别为所述并网点长期运行的最小频率及最大频率；
根据预设的频率额定参考值f ref进行积分运算，得到交流电压相位角参考值；
获取换流站交流并网点的电压测量值和频率测量值，并根据所述电压测量值、所述频率测量值和预设的二次调频控制模型，输出有功功率参考值及无功功率参考值；
测量所述并网点的有功功率及无功功率，并根据所述有功功率参考值、所述无功功率参考值、预设的有功功率控制模型及预设的无功功率控制模型，输出交流电压幅值参考值；
测量所述并网点的交流电压测量值，根据所述交流电压相位角参考值θ对所述交流电压测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电压dq分量值；设定所述并网点的交流电压d分量的电压参考值为所述交流电压幅值参考值，设定所述并网点的交流电压q分量的电压参考值为零；根据设定的交流电压d分量的电压参考值、设定的交流电压q分量的电压参考值和预设的电压控制模型对所述交流电压dq分量值进行控制，并输出电流dq分量参考值；
测量所述并网点的交流电流测量值，根据所述交流电压相位角参考值对所述交流电流测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电流dq分量值；根据所述电流dq分量参考值和预设的电流控制模型对所述交流电流dq分量值进行控制，并输出换流站的阀侧电压dq分量参考值；根据所述交流电压相位角参考值对所述阀侧电压dq分量参考值进行帕克逆变换，从dq坐标系逆变换到abc坐标系，输出换流器三相电压参考波用于换流器阀控制环节。
优选地，所述当所述并网点频率波动在稳定范围内运行时，按照柔性直流输电系统的稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制，具体包括：
当所述并网点频率f满足f min<f<f max时，判定所述并网点频率运行在稳定范围内，其中，f min和f max分别为并网点长期运行的最小频率及最大频率；
获取换流站交流并网点的电压测量值和频率测量值，并根据所述电压测量值、所述频率测量值和预设的二次调频控制模型，输出有功功率参考值及无功功率参考值；
测量所述并网点的有功功率及无功功率，并根据所述有功功率参考值、所述无功功率参考值、预设的有功功率控制模型及预设的无功功率控制模型，输出所述并网点的交流电压相位角参考值及交流电压幅值参考值；
测量所述并网点的交流电压测量值，根据所述交流电压相位角参考值θ对所述交流电压测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电压dq分量值；设定所述并网点的交流电压d分量的电压参考值为所述交流电压幅值参考值，设定所述并网点的交流电压q分量的电压参考值为零；根据设定的交流电压d分量的电压参考值、设定的交流电压q分量的电压参考值和预设的电压控制模型对所述交流电压dq分 量值进行控制，并输出电流dq分量参考值；
测量所述并网点的交流电流测量值，根据所述交流电压相位角参考值对所述交流电流测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电流dq分量值；根据所述电流dq分量参考值和预设的电流控制模型对所述交流电流dq分量值进行控制，并输出换流站的阀侧电压dq分量参考值；根据所述交流电压相位角参考值对所述阀侧电压dq分量参考值进行帕克逆变换，从dq坐标系逆变换到abc坐标系，输出换流器三相电压参考波用于换流器阀控制环节。
本发明实施例还提供一种基于电网构造型的柔性直流孤岛控制装置，包括处理器、存储器以及存储在所述存储器中且被配置为由所述处理器执行的计算机程序，所述处理器执行所述计算机程序时实现上述实施例中任意一项所述的基于电网构造型的柔性直流孤岛控制方法。
本发明实施例还提供一种计算机可读存储介质，所述计算机可读存储介质包括存储的计算机程序，其中，在所述计算机程序运行时控制所述计算机可读存储介质所在设备执行上述实施例中任意一项所述的基于电网构造型的柔性直流孤岛控制方法。
本发明提供基于电网构造型的柔性直流孤岛控制方法、装置及介质，基于电网构造型控制，在柔性直流输电系统在构网型控制系统框架下，柔性直流输电系统接入的交流电网拓扑结构由联网型改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点频率；当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制；为避免采用构网型控制策略时，所述并网点频率偏离稳定范围后，继续采用构网型控制策略，导致所述并网点频率超出极端运行频率，使得直流系统停止运行，造成的系统不稳定，提高了系统控制过程的稳定性。
附图说明
图1是本发明实施例提供的一种基于电网构造型的柔性直流孤岛控制方法的流程示意图；
图2是本发明实施例提供的一种基于电网构造型的柔性直流孤岛控制方法的交流电压相位角参考值获取模型的结构示意图；
图3是本发明实施例提供的一种二次调频控制模型生成有功功率参考值的框架图；
图4是本发明实施例提供的一种二次调频控制模型生成无功功率参考值的框架图；
图5是本发明实施例提供的一种功率控制模型的控制框架图；
图6是本发明实施例提供的一种电压控制模型的控制框架图；
图7是本发明实施例提供的一种电流控制模型的控制框架图；
图8是本发明实施例提供的一种基于电网构造型的柔性直流孤岛控制装置的结构示意图；
图9是本发明又一实施例提供的基于电网构造型的柔性直流孤岛控制装置的结构示意图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明实施例提供一种基于电网构造型的柔性直流孤岛控制方法，参见图1所示，是本发明实施例提供的一种基于电网构造型的柔性直流孤岛控制方法的流程示意图，包括步骤S101～S102：
S101，柔性直流输电系统接入电网拓扑结构改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点的并网点频率；
S102，当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制。
在本实施例具体实施时，在柔性支流电网在构网型控制系统框架下，接入电网由联网型转变为孤岛型电网后，为避免构网型控制策略下由于，柔性直流输电系统的并网点的频率发生较大的波动，需要检测所述并网点的并网点频率；
当识别到所述并网点频率波动至极端频率范围时，为避免继续采用构网型控制策略，将会导致所述并网点频率越来越偏离稳定范围，当所述并网点频率超出极端运行频率，将会导致直流系统停止运行，此时，根据预设的频率额定参考值输出交流电压相位角参考值，并进行所述柔性直流输电系统的电压控制和电流控制；
本发明实施例提供一种基于电网构造型的柔性直流孤岛控制方法，在柔性支流电网在构网型控制系统框架下，柔性直流输电系统接入电网拓扑结构改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点的并网点频率；当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制；为避免采用构网型控制策略时，所述并网点频率偏离稳定范围后，继续采用构网型控制策略，导致所述并网点频率超出极端运行频率，使得直流系统停止运行，造成的系统不稳定，提高了系统控制过 程的稳定性。
本发明提供的又一实施例中，所述方法还包括步骤S103：
当所述并网点频率波动在稳定范围内运行时，按照柔性直流输电系统的稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制。
在本实施例具体实施时，当柔性直流输电系统接入电网由联网型转为孤岛型后，若接入电网状态变化前后所引起的功率变化较小，引起并网点频率偏移，所述并网点频率在稳定范围内，则所述柔性直流输电系统仍能在稳态下运行，保持该情况下由直流系统提供的频率保持在稳定范围内运行，按照柔性直流输电系统的稳态控制方法控制所述柔性直流输电系统。
当柔性直流输电系统有联网型切换为孤岛型后，当并网点频率保持在稳定范围内，按照柔性直流输电系统的稳态控制方法控制所述柔性直流输电系统，实现对所述柔性直流输电系统的稳定控制。
在本发明提供的又一实施例中，步骤S102，具体包括：
当所述并网点频率f满足f exmin<f<f min或f max<f<f exmax时，判定所述并网点频率运行至极端频率范围，其中，f exmin为所述并网点极端运行频率下限和f exmax并网点极端运行频率上限，f min和f max分别为所述并网点长期运行的最小频率及最大频率；
根据预设的频率额定参考值f ref进行积分运算，得到交流电压相位角参考值；
获取换流站交流并网点的电压测量值和频率测量值，并根据所述电压测量值、所述频率测量值和预设的二次调频控制模型，输出有功功率参考值及无功功率参考值；
测量所述并网点的有功功率及无功功率，并根据所述有功功率参考值、所述无功功率参考值、预设的有功功率控制模型及预设的无功功率控制模型，输出交流电压幅值参考值；
测量所述并网点的交流电压测量值，根据所述交流电压相位角参考值θ对所述交流电压测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电压dq分量值；设定所述并网点的交流电压d分量的电压参考值为所述交流电压幅值参考值，设定所述并网点的交流电压q分量的电压参考值为零；根据设定的交流电压d分量的电压参考值、设定的交流电压q分量的电压参考值和预设的电压控制模型对所述交流电压dq分量值进行控制，并输出电流dq分量参考值；
测量所述并网点的交流电流测量值，根据所述交流电压相位角参考值对所述交流电流测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电流dq分量值；根据所述电流dq分量参考值和预设的电流控制模型对所述交流电流dq分量值进行控制，并输出换流站的阀侧电压dq分量参考值；根据所述交流电压相位角参考值对所 述阀侧电压dq分量参考值进行帕克逆变换，从dq坐标系逆变换到abc坐标系，输出换流器三相电压参考波用于换流器阀控制环节。
在本实施例具体实施时，实时检测所述并网点频率，并进行判定，当所述并网点频率f满足f exmin<f<f min或f max<f<f exmax时，判定所述并网点频率运行至极端频率范围，其中，f exmin为所述并网点极端运行频率下限和f exmax并网点极端运行频率上限，f min和f max分别为所述并网点长期运行的最小频率及最大频率；
参见图2所示，是本发明实施例提供的一种基于电网构造型的柔性直流孤岛控制方法的交流电压相位角参考值获取模型的结构示意图；
获取预设的频率额定参考值f ref，对进行通过积分算子1/s进行积分运算，得到交流电压相位角参考值θ；
获取换流站交流并网点的电压测量值得到所述并网点的交流电源的幅值V m和所述并网点的交流电源频率f m；
通过二次调频控制模型：
Figure PCTCN2021131700-appb-000001
和
Figure PCTCN2021131700-appb-000002
输出功率参考值，包括：有功功率参考值P ref和无功功率参考值Q ref,其中，
f ref和V mref分别为所述并网点的频率额定参考值和电压额定参考值，P nom和Q nom分别为直流系统主回路设计时额定有功功率及额定无功功率，P set和Q set分别为调度系统设定的二次调频有功功率的基准值和二次调频无功功率的基准值，T p和T q分别为决定二次调频动态响应时间的有功功率时间常数控制参数和无功功率时间常数控制参数，σ p和σ q分别为有功功率二次调频贡献因素和无功功率二次调频贡献因素。
测量所述并网点的有功功率P及无功功率Q，并根据所述有功参考值和无功功率参考值；根据同步发电机运动方程构建的有功功率控制模型和无功功率控制模型：
Figure PCTCN2021131700-appb-000003
和
Figure PCTCN2021131700-appb-000004
生成所述并网点的所述交流电压幅值参考值V mref；其中，
J p和J q分别为虚拟同步控制惯量常数，D P和D q分别为有功无功功率虚拟同步控制调节常数和无功功率虚拟同步控制调节常数，ω ref为所述并网点的频率额定参考值f ref的角速度，即ω ref＝2πf ref，ω＝2πf，f为所连电网频率，在稳态情况下，f＝f ref。
通过测量所述并网点的交流电压测量值V abc，根据交流电压相位角参考值θ将所述交流电压测量值V abc进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系得到交流电压dq分量电压值V dq；
设定所述交流电压幅值参考值V mref为所述交流电压d分量V d的电压参考值V dref，设定0为所述交流电压q分量V q的参考值V qref，即V dref＝V mref，V qref＝0；
分别根据所述交流电压d分量V d的电压参考值V dref和交流电压q分量V q的电压参考值V qref对所述交流电压dq分量V d和V q进行控制，输出交流电流dq分量的参考值I dref和I qref。
通过测量所述并网点的交流电流测量值I abc，根据所述交流电压相位角参考值θ将三相交流电流实际值I abc进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系得到所述并网点交流电流dq分量电流值I dq；
通过电流控制模型，使得并网点交流电流dq分量I d和I q分别跟随所述电流参考值I dref和I qref，生成阀侧电压dq分量参考波V cdref和V cqref；
根据所述交流电压相位角参考值θ将阀侧电压参考波进行帕克逆变换，从dq坐标系逆变换到abc坐标系得到阀侧三相电压参考波V cabc作为换流器阀控制环节的输入量。
为避免采用构网型控制策略时，所述并网点频率偏离稳定范围后，继续采用构网型控制策略，导致所述并网点频率超出极端运行频率，使得直流系统停止运行，造成的系统不稳定，提 高了系统控制过程的稳定性。
在本发明提供的又一实施例中，步骤S103具体包括：
当所述并网点频率f满足f min<f<f max时，判定所述并网点频率运行在稳定范围内，其中，f min和f max分别为并网点长期运行的最小频率及最大频率；
获取换流站交流并网点的电压测量值和频率测量值，并根据所述电压测量值、所述频率测量值和预设的二次调频控制模型，输出有功功率参考值及无功功率参考值；
测量所述并网点的有功功率及无功功率，并根据所述有功功率参考值、所述无功功率参考值、预设的有功功率控制模型及预设的无功功率控制模型，输出所述并网点的交流电压相位角参考值及交流电压幅值参考值；
测量所述并网点的交流电压测量值，根据所述交流电压相位角参考值θ对所述交流电压测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电压dq分量值；设定所述并网点的交流电压d分量的电压参考值为所述交流电压幅值参考值，设定所述并网点的交流电压q分量的电压参考值为零；根据设定的交流电压d分量的电压参考值、设定的交流电压q分量的电压参考值和预设的电压控制模型对所述交流电压dq分量值进行控制，并输出电流dq分量参考值；
测量所述并网点的交流电流测量值，根据所述交流电压相位角参考值对所述交流电流测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电流dq分量值；根据所述电流dq分量参考值和预设的电流控制模型对所述交流电流dq分量值进行控制，并输出换流站的阀侧电压dq分量参考值；根据所述交流电压相位角参考值对所述阀侧电压dq分量参考值进行帕克逆变换，从dq坐标系逆变换到abc坐标系，输出换流器三相电压参考波用于换流器阀控制环节。
在本实施例具体实施时，当所述并网点频率f满足f min<f<f max时，判定所述并网点频率运行在稳定范围内，其中，f min和f max分别为并网点长期运行的最小频率及最大频率；
判定并网点频率运行在稳定范围内时，按照柔性直流输电系统的稳态控制方法控制所述柔性直流输电系统，具体过程如下：
先测量换流站交流并网点处的电压测量值V m和所述并网点处的频率测量值f m；
通过预设的二次调频控制模型：
Figure PCTCN2021131700-appb-000005
Figure PCTCN2021131700-appb-000006
获取功率参考值，功率参考值包括有功功率参考值P ref和无功功率参考值Q ref；此外，所述二次调频控制模型中包含提前获取的电力系统的参数信息，具体为：f ref和V mref分别为所述并网点的频率额定参考值和电压额定参考值，P nom和Q nom分别为直流系统主回路设计时额定有功功率及额定无功功率，P set和Q set分别为调度系统设定的二次调频有功功率的基准值和二次调频无功功率的基准值，T p和T q分别为决定二次调频动态响应时间的有功功率时间常数控制参数和无功功率时间常数控制参数，σ p和σ q分别为有功功率二次调频贡献因素和无功功率二次调频贡献因素。
参见图3所示，是本发明实施例提供的的二次调频控制模型生成有功功率参考值的框架图，当输入二次调频控制模型的输入量：频率额定参考值f ref、频率测量值f m、调度系统设定的二次调频有功功率的基准值P set，二次调频控制模型根据频率额定参考值f ref、直流系统主回路设计时额定有功功率P nom、有功功率二次调频的贡献因素σ p，以及有功功率时间常数控制参数T p，输出有功功率参考值P ref；
参见图4所示，是本发明实施例提供的一种二次调频控制模型生成无功功率参考值的框架图，当输入二次调频控制模型的输入量，电压额定参考值V mref、电压测量值V m、调度系统设定的二次调频无功功率的基准值Q set，二次调频控制模型根据电压额定参考值V mref、直流系统主回路设计时额定无功功率Q nom、无功功率二次调频的贡献因素σ q，以及无功功率时间常数控制参数T q，输出无功功率参考值Q ref；
通过二次调频控制模型来生成功率参考值为准稳态控制环节，其动态响应时间精度为秒级，能够在并网点电压或频率发生偏离后，通过生成的有功/无功功率参考值来减少频率幅值和电压幅值的偏离程度。
在功率控制环节，先测量所述并网点的有功功率电压值P和无功功率电压值Q；
将测量的有功功率电压值P和无功功率电压值Q以及二次调频控制模型输出的有功功率 参考值P ref和无功功率参考值Q ref输入到预设的功率控制模型：
Figure PCTCN2021131700-appb-000007
Figure PCTCN2021131700-appb-000008
输出电压参考值，包括，交流电压相位角参考值θ及所述交流电压幅值参考值V mref；
其中，P为测量的所述有功功率电压值，Q为测量的所述无功功率电压值，θ为直流系统接入电网的相角，f为所连电网频率，J p和J q分别为虚拟同步控制惯量常数，D P和D q分别为有功/无功功率虚拟同步控制调节常数ω ref为所述并网点的频率额定参考值f ref的角速度，即ω ref＝2πf ref，f为所连电网频率，在稳态情况下，f＝f ref。
在稳态情况下，有功功率电压值P＝有功功率参考值P ref，所连电网频率f＝频率额定参考值f ref，当直流系统所连接交流系统频率发生变化时，若频率额定参考值f增大时，Δf＝f-f ref≠0，则有功功率电压值也会在功率控制模型作用下快速调节至新的稳定值，确保系统保持平衡平衡点。
当无功功率电压值发生变化，工作原理与有功功率情况基本类似，在此不做赘述。
参见图5所示，是本发明实施例提供的一种功率控制模型的控制框架图，输入有功功率电压值P、有功功率参考值P ref、无功功率电压值Q、无功功率参考值Q ref，经过图示的流程，能够完成对有功/无功功率电压的稳定并输出电压参考值θ和V mref；
功率控制模型的响应的精度为毫秒级，对应为同步电机控制的一次调频环节。功率控制环节模拟了同步发电机的运动方程，通过功率控制对网侧并网点电压的幅值和相角进行构造，使柔直系统具备自同步功能和快速调频调压能力，正常运行时控制环节中无需锁相环。
参见图6所示，是本发明实施例提供的一种电压控制模型的控制框架图，分别根据所述并网点交流电压dq分量的参考值V dref和V qref对并网点实际交流电压dq分量V d和V q进行控制，输出并网点交流电流dq分量的参考值I dref和I qref。。
参见图7所示，是本发明实施例提供的一种电流控制模型的控制框架图。通过电流控制模 型，使得并网点交流电流dq分量I d和I q分别跟随所述电流参考值I dref和I qref，生成阀侧电压dq分量参考波V cdref和V cqref；
根据所述相角θ将阀侧电压参考波进行帕克逆变换，从dq坐标系逆变换到abc坐标系得到阀侧三相电压参考波V cabc作为换流器阀控制环节的输入量。
通过，引入二次调频控制模型，能够充分将同步电机的调频调压特性应用到直流输电系统中，进一步模拟直流系统的同步电机特性，可以更方便的将直流系统等效于同步电机电网，能够在毫秒级响应系统变化，调节直流系统的无功/有功的功率、电压、电流，维持直流系统的稳定性。
本发明实施例提供一种基于电网构造型的柔性直流孤岛控制方法，在柔性支流电网在构网型控制系统框架下，柔性直流输电系统接入电网拓扑结构改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点的并网点频率；当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制；为避免采用构网型控制策略时，所述并网点频率偏离稳定范围后，继续采用构网型控制策略，导致所述并网点频率超出极端运行频率，使得直流系统停止运行，造成的系统不稳定，提高了系统控制过程的稳定性。
本发明实施例还提供一种基于电网构造型的柔性直流孤岛控制装置，参见图8，是本发明实施例提供的一种基于电网构造型的柔性直流孤岛控制装置的结构示意图，所述装置包括频率检测模块和第一控制模块；
所述频率检测模块用于柔性直流输电系统接入电网拓扑结构改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点的并网点频率；
所述第一控制模块用于当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制。
本装置各个模块的具体功能在本发明提供的任一基于电网构造型的柔性直流孤岛控制方法的实施例中做了具体说明，在此不作赘述。
参见图9，是本发明又一实施例提供的基于电网构造型的柔性直流孤岛控制装置的结构示意图。该实施例的基于电网构造型的柔性直流孤岛控制装置包括：处理器、存储器以及存储在所述存储器中并可在所述处理器上运行的计算机程序，例如基于电网构造型的柔性直流孤岛控制程序。所述处理器执行所述计算机程序时实现上述各个基于电网构造型的柔性直流孤岛控制 方法实施例中的步骤，例如图1所示的步骤S101～S103。或者，所述处理器执行所述计算机程序时实现上述各装置实施例中各模块/单元的功能。
示例性的，所述计算机程序可以被分割成一个或多个模块/单元，所述一个或者多个模块/单元被存储在所述存储器中，并由所述处理器执行，以完成本发明。所述一个或多个模块/单元可以是能够完成特定功能的一系列计算机程序指令段，该指令段用于描述所述计算机程序在所述基于电网构造型的柔性直流孤岛控制装置中的执行过程。例如，所述计算机程序可以被分割成功率参考值设定模块、功率控制模块、电压控制模块和电流控制模块，各模块具体功能在此不做赘述.。
所述基于电网构造型的柔性直流孤岛控制装置可以是桌上型计算机、笔记本、掌上电脑及云端服务器等计算设备。所述基于电网构造型的柔性直流孤岛控制装置可包括，但不仅限于，处理器、存储器。本领域技术人员可以理解，所述示意图仅仅是基于电网构造型的柔性直流孤岛控制装置的示例，并不构成对基于电网构造型的柔性直流孤岛控制装置的限定，可以包括比图示更多或更少的部件，或者组合某些部件，或者不同的部件，例如所述基于电网构造型的柔性直流孤岛控制装置还可以包括输入输出设备、网络接入设备、总线等。
所称处理器可以是中央处理单元(Central Processing Unit，CPU)，还可以是其他通用处理器、数字信号处理器(Digital Signal Processor，DSP)、专用集成电路(Application Specific Integrated Circuit，ASIC)、现场可编程门阵列(Field-Programmable Gate Array，FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等，所述处理器是所述基于电网构造型的柔性直流孤岛控制装置的控制中心，利用各种接口和线路连接整个基于电网构造型的柔性直流孤岛控制装置的各个部分。
所述存储器可用于存储所述计算机程序和/或模块，所述处理器通过运行或执行存储在所述存储器内的计算机程序和/或模块，以及调用存储在存储器内的数据，实现所述基于电网构造型的柔性直流孤岛控制装置的各种功能。所述存储器可主要包括存储程序区和存储数据区，其中，存储程序区可存储操作系统、至少一个功能所需的应用程序(比如声音播放功能、图像播放功能等)等；存储数据区可存储根据手机的使用所创建的数据(比如音频数据、电话本等)等。此外，存储器可以包括高速随机存取存储器，还可以包括非易失性存储器，例如硬盘、内存、插接式硬盘，智能存储卡(Smart Media Card,SMC)，安全数字(Secure Digital,SD)卡，闪存卡(Flash Card)、至少一个磁盘存储器件、闪存器件、或其他易失性固态存储器件。
其中，所述基于电网构造型的柔性直流孤岛控制装置集成的模块/单元如果以软件功能单 元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本发明实现上述实施例方法中的全部或部分流程，也可以通过计算机程序来指令相关的硬件来完成，所述的计算机程序可存储于一计算机可读存储介质中，该计算机程序在被处理器执行时，可实现上述各个方法实施例的步骤。其中，所述计算机程序包括计算机程序代码，所述计算机程序代码可以为源代码形式、对象代码形式、可执行文件或某些中间形式等。所述计算机可读介质可以包括：能够携带所述计算机程序代码的任何实体或装置、记录介质、U盘、移动硬盘、磁碟、光盘、计算机存储器、只读存储器(ROM，Read-Only Memory)、随机存取存储器(RAM，Random Access Memory)、电载波信号、电信信号以及软件分发介质等。需要说明的是，所述计算机可读介质包含的内容可以根据司法管辖区内立法和专利实践的要求进行适当的增减，例如在某些司法管辖区，根据立法和专利实践，计算机可读介质不包括电载波信号和电信信号。
本发明提供的基于电网构造型的柔性直流孤岛控制方法、装置及介质，在柔性直流输电系统在构网型控制系统框架下，柔性直流输电系统接入的交流电网拓扑结构由联网型改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点频率；当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制；为避免采用构网型控制策略时，所述并网点频率偏离稳定范围后，继续采用构网型控制策略，导致所述并网点频率超出极端运行频率，使得直流系统停止运行，造成的系统不稳定，提高了系统控制过程的稳定性。
需说明的是，以上所描述的装置实施例仅仅是示意性的，其中所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部模块来实现本实施例方案的目的。另外，本发明提供的装置实施例附图中，模块之间的连接关系表示它们之间具有通信连接，具体可以实现为一条或多条通信总线或信号线。本领域普通技术人员在不付出创造性劳动的情况下，即可以理解并实施。
以上所述是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也视为本发明的保护范围。

Claims (10)

  1. 一种基于电网构造型的柔性直流孤岛控制方法，其特征在于，所述方法包括：柔性直流输电系统接入电网拓扑结构改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点频率；
    当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制。
  2. 根据权利要求1所述的基于电网构造型的柔性直流孤岛控制方法，其特征在于，所述方法还包括：
    当所述并网点频率波动在稳定范围内运行时，按照柔性直流输电系统的稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制。
  3. 根据权利要求1所述的基于电网构造型的柔性直流孤岛控制方法，其特征在于，所述当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制，具体包括：
    当所述并网点频率f满足f exmin<f<f min或f max<f<f exmax时，判定所述并网点频率运行至极端频率范围，其中，f exmin为并网点极端运行频率下限和f exmax并网点极端运行频率上限，f min和f max分别为所述并网点长期运行的最小频率及最大频率；
    根据预设的频率额定参考值f ref进行积分运算，得到交流电压相位角参考值；
    获取换流站交流并网点的电压测量值和频率测量值，并根据所述电压测量值、所述频率测量值和预设的二次调频控制模型，输出有功功率参考值及无功功率参考值；
    测量所述并网点的有功功率及无功功率，并根据所述有功功率参考值、所述无功功率参考值、预设的有功功率控制模型及预设的无功功率控制模型，输出交流电压幅值参考值；
    测量所述并网点的交流电压测量值，根据所述交流电压相位角参考值θ对所述交流电压测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电压dq分量值；设定所述并网点的交流电压d分量的电压参考值为所述交流电压幅值参考值，设定所述并网点的交流电压q分量的电压参考值为零；根据设定的交流电压d分量的电压参考值、设定的交流电压q分量的电压参考值和预设的电压控制模型对所述交流电压dq分 量值进行控制，并输出电流dq分量参考值；
    测量所述并网点的交流电流测量值，根据所述交流电压相位角参考值对所述交流电流测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电流dq分量值；根据所述电流dq分量参考值和预设的电流控制模型对所述交流电流dq分量值进行控制，并输出换流站的阀侧电压dq分量参考值；根据所述交流电压相位角参考值对所述阀侧电压dq分量参考值进行帕克逆变换，从dq坐标系逆变换到abc坐标系，输出换流器三相电压参考波用于换流器阀控制环节。
  4. 根据权利要求2所述的基于电网构造型的柔性直流孤岛控制方法，其特征在于，所述当所述并网点频率波动在稳定范围内运行时，按照柔性直流输电系统的稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制，具体包括：
    当所述并网点频率f满足f min<f<f max时，判定所述并网点频率运行在稳定范围内，其中，f min和f max分别为并网点长期运行的最小频率及最大频率；
    获取换流站交流并网点的电压测量值和频率测量值，并根据所述电压测量值、所述频率测量值和预设的二次调频控制模型，输出有功功率参考值及无功功率参考值；
    测量所述并网点的有功功率及无功功率，并根据所述有功功率参考值、所述无功功率参考值、预设的有功功率控制模型及预设的无功功率控制模型，输出所述并网点的交流电压相位角参考值及交流电压幅值参考值；
    测量所述并网点的交流电压测量值，根据所述交流电压相位角参考值θ对所述交流电压测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电压dq分量值；设定所述并网点的交流电压d分量的电压参考值为所述交流电压幅值参考值，设定所述并网点的交流电压q分量的电压参考值为零；根据设定的交流电压d分量的电压参考值、设定的交流电压q分量的电压参考值和预设的电压控制模型对所述交流电压dq分量值进行控制，并输出电流dq分量参考值；
    测量所述并网点的交流电流测量值，根据所述交流电压相位角参考值对所述交流电流测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电流dq分量值；根据所述电流dq分量参考值和预设的电流控制模型对所述交流电流dq分量值进行控制，并输出换流站的阀侧电压dq分量参考值；根据所述交流电压相位角参考值对所述阀侧电压dq分量参考值进行帕克逆变换，从dq坐标系逆变换到abc坐标系，输出换流器三相电压参考波用于换流器阀控制环节。
  5. 一种基于电网构造型的柔性直流孤岛控制装置，其特征在于，包括：频率检测模块和第一控制模块；
    所述频率检测模块用于柔性直流输电系统接入电网拓扑结构改变为仅孤岛型电网与直流系统连接后，检测所述柔性直流输电系统的并网点的并网点频率；
    所述第一控制模块用于当所述并网点频率波动至极端频率范围时，根据预设的频率额定参考值输出交流电压相位角参考值，根据所述交流电压相位角参考值和稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制。
  6. 根据权利要求5所述的基于电网构造型的柔性直流孤岛控制装置，其特征在于，所述装置还包括第二控制模块；
    所述第二控制模块用于当所述并网点频率波动在稳定范围内运行时，按照柔性直流输电系统的稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制。
  7. 根据权利要求5所述的基于电网构造型的柔性直流孤岛控制装置，其特征在于，所述第一控制模块具体用于：
    当所述并网点频率f满足f exmin<f<f min或f max<f<f exmax时，判定所述并网点频率运行至极端频率范围，其中，f exmin为所述并网点极端运行频率下限和f exmax并网点极端运行频率上限，f min和f max分别为所述并网点长期运行的最小频率及最大频率；
    根据预设的频率额定参考值f ref进行积分运算，得到交流电压相位角参考值；
    获取换流站交流并网点的电压测量值和频率测量值，并根据所述电压测量值、所述频率测量值和预设的二次调频控制模型，输出有功功率参考值及无功功率参考值；
    测量所述并网点的有功功率及无功功率，并根据所述有功功率参考值、所述无功功率参考值、预设的有功功率控制模型及预设的无功功率控制模型，输出交流电压幅值参考值；
    测量所述并网点的交流电压测量值，根据所述交流电压相位角参考值θ对所述交流电压测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电压dq分量值；设定所述并网点的交流电压d分量的电压参考值为所述交流电压幅值参考值，设定所述并网点的交流电压q分量的电压参考值为零；根据设定的交流电压d分量的电压参考值、设定的交流电压q分量的电压参考值和预设的电压控制模型对所述交流电压dq分量值进行控制，并输出电流dq分量参考值；
    测量所述并网点的交流电流测量值，根据所述交流电压相位角参考值对所述交流电流测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电流dq分量值；根据所述电流dq分量参考值和预设的电流控制模型对所述交流电流dq分量值进行控制，并输出换流站的阀侧电压dq分量参考值；根据所述交流电压相位角参考值对所述阀侧电压dq分量参考值进行帕克逆变换，从dq坐标系逆变换到abc坐标系，输出换流器三相电压参考波用于换流器阀控制环节。
  8. 根据权利要求6所述的基于电网构造型的柔性直流孤岛控制装置，其特征在于，所述当所述并网点频率波动在稳定范围内运行时，按照柔性直流输电系统的稳态控制方法进行所述柔性直流输电系统的功率控制、电压控制和电流控制，具体包括：
    当所述并网点频率f满足f min<f<f max时，判定所述并网点频率运行在稳定范围内，其中，f min和f max分别为并网点长期运行的最小频率及最大频率；
    获取换流站交流并网点的电压测量值和频率测量值，并根据所述电压测量值、所述频率测量值和预设的二次调频控制模型，输出有功功率参考值及无功功率参考值；
    测量所述并网点的有功功率及无功功率，并根据所述有功功率参考值、所述无功功率参考值、预设的有功功率控制模型及预设的无功功率控制模型，输出所述并网点的交流电压相位角参考值及交流电压幅值参考值；
    测量所述并网点的交流电压测量值，根据所述交流电压相位角参考值θ对所述交流电压测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电压dq分量值；设定所述并网点的交流电压d分量的电压参考值为所述交流电压幅值参考值，设定所述并网点的交流电压q分量的电压参考值为零；根据设定的交流电压d分量的电压参考值、设定的交流电压q分量的电压参考值和预设的电压控制模型对所述交流电压dq分量值进行控制，并输出电流dq分量参考值；
    测量所述并网点的交流电流测量值，根据所述交流电压相位角参考值对所述交流电流测量值进行帕克变换，将三相交流电气量从abc坐标系变换到dq坐标系，输出所述并网点的交流电流dq分量值；根据所述电流dq分量参考值和预设的电流控制模型对所述交流电流dq分量值进行控制，并输出换流站的阀侧电压dq分量参考值；根据所述交流电压相位角参考值对所述阀侧电压dq分量参考值进行帕克逆变换，从dq坐标系逆变换到abc坐标系，输出换流器三相电压参考波用于换流器阀控制环节。
  9. 一种基于电网构造型的柔性直流孤岛控制装置，其特征在于，包括处理器、存储器以及存储在所述存储器中且被配置为由所述处理器执行的计算机程序，所述处理器执行所述计算机程序时实现如权利要求1至4中任意一项所述的基于电网构造型的柔性直流孤岛控制方法。
  10. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质包括存储的计算机程序，其中，在所述计算机程序运行时控制所述计算机可读存储介质所在设备执行如权利要求1至4中任意一项所述的基于电网构造型的柔性直流孤岛控制方法。
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