CN115173457A - Flexible direct current receiving end alternating current fault ride-through method, system and computer equipment - Google Patents
Flexible direct current receiving end alternating current fault ride-through method, system and computer equipment Download PDFInfo
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- CN115173457A CN115173457A CN202210794834.9A CN202210794834A CN115173457A CN 115173457 A CN115173457 A CN 115173457A CN 202210794834 A CN202210794834 A CN 202210794834A CN 115173457 A CN115173457 A CN 115173457A
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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
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
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- 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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Abstract
The application relates to a flexible direct current receiving end alternating current fault ride-through method, a system, computer equipment, a storage medium and a computer program product. The method comprises the following steps: when receiving end alternating current fault signals of a receiving end alternating current system, controlling a transmitting end converter to switch to a capacitor voltage average value control mode; acquiring a capacitor voltage average value of the sending end converter and a capacitor voltage reference value of the sending end converter; determining a target sending end direct-current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value; and controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting the capacitor voltage average value control mode. By adopting the method, the problem of capacitor voltage fluctuation of the converter at the transmitting end after the converter at the receiving end is put into the direct current energy consumption device can be solved, and the stability of an alternating current system at the transmitting end is improved.
Description
Technical Field
The present application relates to the field of power engineering technologies, and in particular, to a receiving-end ac fault ride-through method, system, computer device, storage medium, and computer program product.
Background
The installed capacity of the new energy station is greatly increased, and the distribution is more and more extensive. The adoption of flexible direct current to convey new energy sources becomes a current research hotspot. The sending end alternating current system is a large-scale photovoltaic system and transmits power to the receiving end alternating current system through a sending end converter, a direct current circuit and a receiving end converter.
When the fault of the receiving end alternating current system occurs at present, the receiving end alternating current fault passes through the receiving end converter, the receiving end alternating current system fault is detected, the direct current energy consumption device is put into use, and when the fault of the receiving end alternating current system is cleared, the direct current energy consumption device is cut off, so that the capacitor voltage of the sending end converter is large in fluctuation, and potential safety hazards exist.
Disclosure of Invention
Based on this, it is necessary to provide a flexible dc receiving end ac fault ride-through method, system, computer device, computer readable storage medium and computer program product capable of solving the problem of voltage fluctuation of a transmitting end converter capacitor after a receiving end converter is put into a dc energy consuming device.
In a first aspect, the application provides a flexible direct current receiving end alternating current fault ride-through method. The method comprises the following steps:
when receiving end alternating current fault signals of a receiving end alternating current system, controlling a transmitting end converter to switch to a capacitor voltage average value control mode;
acquiring a capacitor voltage average value of the sending end converter and a capacitor voltage reference value of the sending end converter;
determining a target sending end direct-current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value;
and controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting the capacitor voltage average value control mode.
In one embodiment, the determining a target sending end direct current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value comprises:
obtaining a capacitance voltage change value of the sending end converter under the condition of the fault of the receiving end alternating current system according to the difference value of the square of the capacitance voltage average value and the square of the capacitance voltage reference value;
obtaining the variation of the direct-current voltage reference value of the sending-end converter by performing proportional-integral control on the capacitance voltage variation value;
and superposing the variation of the direct-current voltage reference value and the sending-end direct-current voltage reference value of the sending-end converter to obtain a target sending-end direct-current voltage reference value of the sending-end converter.
In one embodiment, before the controlling the sending-end converter to switch the capacitor voltage average value control mode, the method further comprises:
and detecting whether the capacitor voltage average value is larger than the capacitor voltage reference value, if so, controlling a sending end converter to switch a capacitor voltage average value control mode.
In one embodiment, the method further comprises:
when the capacitor voltage average value control mode is exited, acquiring the variable quantity of the direct-current voltage reference value of the sending-end converter;
and controlling the change amount of the direct-current voltage reference value to linearly change to zero according to a set rate.
In one embodiment, the controlling the sending-end converter to switch to the capacitor voltage average value control mode when receiving a receiving-end alternating current fault signal of a receiving-end alternating current system comprises:
when receiving end alternating current fault signals of a receiving end alternating current system are received, controlling a sending end converter to be switched to a capacitor voltage average value control mode, triggering a timer to start timing, and executing the step of acquiring the capacitor voltage average value of the sending end converter and the capacitor voltage reference value of the sending end converter;
the controlling the sending power of the dc side of the sending end converter according to the target sending end dc voltage reference value until the capacitor voltage of the sending end converter is in a stable state includes:
controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value to obtain the timing duration of the timer;
if the timing time reaches a preset time and the fault of the receiving end alternating current system is cleared, indicating that the capacitor voltage of the sending end converter is in a stable state; and the preset time length is longer than the fault clearing time length of the receiving end alternating current system.
In one embodiment, the method further comprises:
and if the timing duration reaches a preset duration and the fault of the receiving end alternating current system is not cleared, triggering the timer to count again, executing the step of controlling the sending end converter to be switched to the capacitor voltage average value control mode until the capacitor voltage of the sending end converter is in a stable state, and exiting the capacitor voltage average value control mode.
In a second aspect, the application further provides a flexible dc receiving ac fault ride-through system. The system comprises:
the system includes receiving end AC system, receiving end transverter and send end transverter, receiving end AC system with receiving end transverter links to each other, receiving end transverter and send end transverter pass through direct current circuit and link to each other, receiving end transverter includes first control module, send end transverter includes second control module, wherein:
the first control module is used for acquiring a receiving end alternating current fault signal of the receiving end alternating current system and sending the receiving end alternating current fault signal to the sending end current converter when detecting that the receiving end alternating current system sends a fault;
the second control module is used for controlling the sending end converter to be switched to a capacitor voltage average value control mode when receiving a receiving end alternating current fault signal of a receiving end alternating current system; and controlling the sending power of the direct current side of the sending end converter based on the capacitor voltage average value control mode until the capacitor voltage of the sending end converter is in a stable state.
In a third aspect, the present application also provides a computer device. The computer device comprises a memory storing a computer program and a processor implementing the following steps when executing the computer program:
when receiving end alternating current fault signals of a receiving end alternating current system, controlling a transmitting end converter to switch to a capacitor voltage average value control mode;
acquiring a capacitor voltage average value of the sending end converter and a capacitor voltage reference value of the sending end converter;
determining a target sending end direct-current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value;
and controlling the sending power of the DC side of the sending end converter according to the target sending end DC voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting the capacitor voltage average value control mode.
In a fourth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of:
when receiving end alternating current fault signals of a receiving end alternating current system, controlling a transmitting end converter to switch to a capacitor voltage average value control mode;
acquiring a capacitor voltage average value of the sending end converter and a capacitor voltage reference value of the sending end converter;
determining a target sending end direct-current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value;
and controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting the capacitor voltage average value control mode.
In a fifth aspect, the present application further provides a computer program product. The computer program product comprising a computer program which when executed by a processor performs the steps of:
when receiving end alternating current fault signals of a receiving end alternating current system, controlling a transmitting end converter to switch to a capacitor voltage average value control mode;
acquiring a capacitor voltage average value of the sending end converter and a capacitor voltage reference value of the sending end converter;
determining a target sending end direct-current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value;
and controlling the sending power of the DC side of the sending end converter according to the target sending end DC voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting the capacitor voltage average value control mode.
According to the flexible direct-current receiving end alternating-current fault ride-through method, system, computer equipment, storage medium and computer program product, when a fault of a receiving end alternating-current system is detected, a receiving end alternating-current fault signal of the receiving end alternating-current system is sent to a sending end converter through the receiving end converter; when the sending end converter receives a receiving end alternating current fault signal of a receiving end alternating current system, controlling the sending end converter to be switched to a capacitor voltage average value control mode; and controlling the sending power of the direct current side of the sending end converter based on the capacitor voltage average value control mode until the capacitor voltage of the sending end converter is in a stable state. When a receiving end alternating current system breaks down, a receiving end alternating current fault signal is sent to a sending end converter, the sending end converter is controlled to be switched to a capacitor voltage average value control mode, capacitor voltage is stabilized, the problem that capacitor voltage of the sending end converter fluctuates after the receiving end converter is put into a direct current energy consumption device is solved, and stability of the sending end alternating current system is improved.
Drawings
FIG. 1 is a diagram of an exemplary embodiment of an application environment of a flexible DC receiving end AC fault ride-through method;
FIG. 2 is a schematic flow chart illustrating a flexible DC receiving end AC fault ride-through method according to an embodiment;
FIG. 3 is a schematic flow chart illustrating a method for determining a target transmit DC voltage reference for a transmit inverter according to one embodiment;
FIG. 4 is a block diagram illustrating control of the average value of the capacitor voltage in one embodiment;
FIG. 5 is a schematic flow chart illustrating a flexible DC receiving end AC fault ride-through method according to another embodiment;
FIG. 6 is a schematic flow chart illustrating a flexible DC receiving end AC fault ride-through method according to another embodiment;
FIG. 7 is a schematic structural diagram of a system of a flexible DC receiving end AC fault ride-through method in one embodiment;
FIG. 8 is a block diagram of an embodiment of a flexible DC sink AC fault ride-through system;
FIG. 9 is a diagram illustrating an internal structure of a computer device according to an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
The flexible direct current receiving end alternating current fault ride-through method provided by the embodiment of the application can be applied to the application environment shown in fig. 1. Wherein, the sending-side converter 102 communicates with the receiving-side converter 104 through a dc line. The transmitting-side converter 102 is connected to a transmitting-side ac system, and the receiving-side converter 104 is connected to a receiving-side ac system. The data storage system may store data that must be processed by transmit end converter 102. The data storage system may be integrated on the sending-end inverter 102, or may be placed on the cloud or other network server. When the receiving end converter detects that the receiving end alternating current system has a fault, based on communication established by the transmitting end converter and the receiving end converter, transmitting a receiving end alternating current fault signal of the receiving end alternating current system to the transmitting end converter, and when the receiving end alternating current fault signal of the receiving end alternating current system is received, controlling the transmitting end converter to be switched to a capacitor voltage average value control mode; acquiring a capacitor voltage average value of the sending end converter and a capacitor voltage reference value of the sending end converter; determining a target sending end direct-current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value; and controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting from the capacitor voltage average value control mode. The sending-end converters can be different types of sending-end converters, and the receiving-end converters can be different types of receiving-end converters.
In one embodiment, as shown in fig. 2, a flexible dc-to-ac fault ride-through method is provided, which is described by taking the method as an example for being applied to the sending-end converter in fig. 1, and includes the following steps:
The method for detecting whether the receiving end alternating current system has faults comprises multiple modes, and the detection can be carried out through the existing fault detection mode. For example, when detecting whether the receiving-end alternating current system has a fault, it may be determined that the receiving-end alternating current system has a fault by detecting whether the alternating voltage of the receiving-end alternating current system is normal, and if it is detected that the effective value of the alternating voltage is reduced to be less than a fixed value (for example, 0.5 pu).
Specifically, the receiving-end converter detects a fault of the receiving-end alternating current system, and if the receiving-end alternating current system fails, the receiving-end converter is put into a direct current energy consumption device, and the direct current energy consumption device consumes power transmitted by the rectifying side. And sending a receiving end alternating current fault signal of the receiving end alternating current system to the sending end converter, controlling the sending end converter to be switched to a capacitor voltage average value control mode, and stably controlling the sub-module capacitor voltage in the sending end converter.
And step 204, acquiring the average value of the capacitor voltage of the sending end converter and the reference value of the capacitor voltage of the sending end converter.
The sending end converter comprises a plurality of sub-modules, the capacitor voltage of each sub-module is not identical, and when the capacitor voltage of the sending end converter is determined, the capacitor voltage of the sub-modules is averaged to obtain the average value of the capacitor voltage of the sending end converter.
And step 206, determining a target sending end direct current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value.
Specifically, when a receiving end alternating current fault signal of a receiving end alternating current system is received, the sending end converter is controlled to be switched to a capacitor voltage average value control mode. And under the control mode of the capacitor voltage average value, determining a target sending end direct current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value.
And 208, controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting the capacitor voltage average value control mode.
Specifically, the sending-end converter controls the sending power of the direct current side of the sending-end converter according to the target sending-end direct current voltage reference value until the capacitor voltage of the sending-end converter is in a stable state, and the capacitor voltage average value control mode is exited. At the moment, the fault of the receiving end alternating current system is cleared, the receiving end converter cuts off the direct current energy consumption device, and energy source transmission between the transmitting end alternating current system and the receiving end alternating current system is recovered.
According to the flexible direct-current receiving end alternating current fault ride-through method, when a receiving end alternating current system is detected to have a fault, a receiving end alternating current fault signal of the receiving end alternating current system is sent to a sending end converter through the receiving end converter; when the sending end converter receives a receiving end alternating current fault signal of a receiving end alternating current system, controlling the sending end converter to be switched to a capacitor voltage average value control mode; and controlling the sending power of the direct current side of the sending end converter based on the capacitor voltage average value control mode until the capacitor voltage of the sending end converter is in a stable state. When a receiving end alternating current system breaks down, a receiving end alternating current fault signal is sent to a sending end converter, the sending end converter is controlled to be switched to a capacitor voltage average value control mode, capacitor voltage is stabilized, the problem that capacitor voltage of the sending end converter fluctuates after the receiving end converter is put into a direct current energy consumption device is solved, and stability of the sending end alternating current system is improved.
In one embodiment, as shown in fig. 3, a method for controlling an average value of a capacitor voltage is provided, which is described by taking the method as an example for being applied to the sending-end converter in fig. 1, and includes the following steps:
and step 302, obtaining a capacitance voltage change value of the sending end converter under the condition of the fault of the receiving end alternating current system according to the difference value of the square of the capacitance voltage average value and the square of the capacitance voltage reference value.
And 304, performing proportional-integral control on the capacitance voltage change value to obtain the change quantity of the direct-current voltage reference value of the sending-end converter.
Specifically, a capacitance voltage change value of the sending-end converter under the condition of the fault of the receiving-end alternating current system is input into a proportional-integral (PI) regulator for proportional-integral control, so as to obtain a change quantity of a direct current voltage reference value of the sending-end converter. The PI regulator is a linear controller, which forms a control deviation from a given value and an actual output value, and linearly combines the proportion and integral of the deviation to form a control quantity to control a controlled object.
As shown in fig. 4, which is a schematic diagram of a control block diagram of an average value of a capacitor voltage corresponding to a control mode of the average value of the capacitor voltage in an embodiment, ucap _ ref is a reference value of the capacitor voltage, ucap is the average value of the capacitor voltage, PI is a PI regulator, delta _ Eref is a variation of a reference value of a dc voltage, and Eref is a reference value of the dc voltage. And obtaining a capacitance voltage change value of the sending end converter according to the difference value of the square of the capacitance voltage average value and the square of the capacitance voltage reference value, inputting the capacitance voltage change value into the PI regulator, outputting the change quantity of the direct current voltage reference value, and superposing the change quantity of the direct current voltage reference value and the sending end direct current voltage reference value of the sending end converter to obtain a target sending end direct current voltage reference value of the sending end converter.
And step 306, superposing the variation of the direct-current voltage reference value and the sending-end direct-current voltage reference value of the sending-end converter to obtain a target sending-end direct-current voltage reference value of the sending-end converter.
In the capacitor voltage average value control method, the difference between the square of the capacitor voltage average value and the square of the capacitor voltage reference value is sent to the PI controller to generate the variation of the sending end direct current voltage reference value, the variation is superposed with the sending end direct current voltage reference value of the sending end converter, and finally the sending end direct current voltage reference value is changed. Furthermore, after the reference value of the direct current voltage at the sending end is changed, the current converter at the sending end is controlled according to the changed reference value of the direct current voltage, the sending power at the direct current side of the current converter at the sending end can be changed, and the purpose of stabilizing the capacitor voltage is achieved.
In another embodiment, as shown in fig. 5, a flexible dc-to-ac fault ride-through method is provided, which is described by taking the method as an example applied to the sending-end converter in fig. 1, and includes the following steps:
In step 504, it is detected whether the average value of the capacitor voltage is greater than the reference value of the capacitor voltage, if so, step 508 is executed, otherwise, step 506 is executed.
And detecting whether the average value of the capacitor voltage is greater than the reference value of the capacitor voltage to judge whether the fault of the receiving-end alternating current system is a temporary recoverable fault or a temporary unrecoverable fault. And when the temporary unrecoverable fault is determined, controlling the sending end converter to switch to a capacitor voltage average value control mode, stabilizing the capacitor voltage of the sending end converter, and avoiding the fluctuation of the capacitor voltage of the sending end flexible-direct-current sub-module after the receiving end converter is put into the direct-current energy consumption device.
Step 506, if the average value of the capacitor voltage is smaller than the reference value of the capacitor voltage, it indicates that the fault of the receiving end alternating current system is cleared.
And step 508, determining a target sending end direct current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value.
And step 510, controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting from the capacitor voltage average value control mode.
And step 512, when the capacitor voltage average value control mode is exited, acquiring the variation of the direct current voltage reference value of the sending end converter.
And step 514, controlling the change amount of the direct current voltage reference value to linearly change to zero according to the set rate.
According to the flexible direct-current receiving end alternating current fault ride-through method, when a receiving end alternating current system is detected to have a fault, the receiving end converter is put into a direct current energy consumption device, and meanwhile, a receiving end alternating current fault signal of the receiving end alternating current system is sent to a sending end converter through the receiving end converter. When the sending end converter receives a receiving end alternating current fault signal of a receiving end alternating current system, the sending end converter is controlled to switch a capacitor voltage average value control mode by detecting whether the capacitor voltage average value of the sending end converter is larger than a capacitor voltage reference value or not under the condition that the capacitor voltage average value is larger than the capacitor voltage reference value, and the purpose of stabilizing the capacitor voltage is achieved by changing the sending power of the direct current side of the sending end converter. The problem of capacitor voltage fluctuation of the sending end converter after the receiving end converter is put into the direct current energy consumption device is solved, and the stability of the sending end alternating current system is improved.
Further, when the receiving-end alternating current system fails, the power balance between the receiving-end alternating current system and the sending-end alternating current system is broken, the capacitor voltage of the sending-end converter fluctuates, if the fluctuation range of the capacitor voltage of the sending-end converter is large, the voltage fluctuation of the sending-end alternating current system is large, photovoltaic cannot stabilize phase locking, the fluctuation of the capacitor voltage of the sending-end converter and the voltage of the sending-end alternating current system is further increased, and the sending-end alternating current system loses stability. In order to solve the problem of fluctuation of the transmitting-end converter capacitor voltage and the transmitting-end ac system voltage and to ensure the stability of the transmitting-end ac system, it is necessary to minimize the fluctuation of the transmitting-end converter capacitor voltage when the receiving-end ac system fails.
In another embodiment, as shown in fig. 6, a flexible dc-to-ac fault ride-through method is provided, which is described by taking the method as an example for being applied to the sending-end converter in fig. 1, and includes the following steps:
step 602, when receiving a receiving end ac fault signal of a receiving end ac system, controlling the sending end converter to switch to the capacitor voltage average value control mode, and triggering a timer to start timing.
And 606, determining a target sending end direct current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value.
And step 610, if the timing duration reaches the preset duration and the fault of the receiving-end alternating current system is cleared, indicating that the capacitor voltage of the sending-end converter is in a stable state, and exiting the capacitor voltage average value control mode.
The preset time length is longer than the fault clearing time length of the receiving end alternating current system.
And 612, if the timing duration reaches the preset duration and the fault of the receiving-end alternating current system is not cleared, triggering the timer to count again, executing the step of controlling the sending-end converter to be switched to the capacitor voltage average value control mode until the capacitor voltage of the sending-end converter is in a stable state, and exiting the capacitor voltage average value control mode.
Specifically, if the timing duration reaches the preset duration and the fault of the receiving end alternating current system is not cleared, the timer is triggered to restart, and the sending end converter is controlled to be switched to a capacitor voltage average value control mode; acquiring a capacitor voltage average value of the sending end converter and a capacitor voltage reference value of the sending end converter; determining a target sending end direct-current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value; and controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting from the capacitor voltage average value control mode.
And 614, acquiring the variable quantity of the direct-current voltage reference value of the sending-end converter.
And 616, controlling the change quantity of the direct-current voltage reference value to linearly change to zero according to a set rate.
Specifically, when the exiting capacitor voltage average value control is started, the voltage reference value variation output by the controller in the sending-end converter at the corresponding moment is obtained, and the direct-current voltage reference value variation is controlled to linearly change to zero according to a set rate.
As shown in fig. 7, a system structure schematic diagram of the flexible dc-to-ac fault ride-through method in an embodiment is shown, and includes a sending-end ac system, a sending-end flexible dc converter station, a dc line, a receiving-end flexible dc converter station, and a receiving-end ac system. The sending end alternating current system contains new energy and does not contain a conventional power supply, the new energy power of the sending end alternating current system is sent out to the receiving end flexible direct current converter station through the sending end flexible direct current converter station through a direct current circuit, the receiving end flexible direct current converter station is connected with the receiving end alternating current system, and the receiving end alternating current system contains the conventional power supply. The transmitting end flexible direct current converter station is provided with a corresponding transmitting end converter, and the receiving end flexible direct current converter station is provided with a corresponding receiving end converter.
And the receiving end converter detects the fault of the receiving end alternating current system, and if the receiving end alternating current system has the fault, the receiving end converter is put into a direct current energy consumption device, and the direct current energy consumption device consumes the power transmitted by the rectifying side. And sending a receiving end alternating current fault signal of the receiving end alternating current system to the sending end converter, and controlling the sending end converter to be switched to a capacitor voltage average value control mode. And obtaining the capacitance voltage variation value of the sending end converter according to the difference value of the square of the capacitance voltage average value and the square of the capacitance voltage reference value, inputting the capacitance voltage variation value into the PI regulator, outputting the variation of the direct current voltage reference value, and superposing the variation of the direct current voltage reference value and the sending end direct current voltage reference value of the sending end converter to obtain the target sending end direct current voltage reference value of the sending end converter. And superposing the variation of the direct-current voltage reference value and the sending-end direct-current voltage reference value of the sending-end converter to obtain a target sending-end direct-current voltage reference value of the sending-end converter. And controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting from the capacitor voltage average value control mode. And when the capacitor voltage average value control mode is exited, acquiring the variation of the direct-current voltage reference value of the sending-end converter, and controlling the variation of the direct-current voltage reference value to linearly vary to zero according to a set rate. And after the receiving end alternating current fault is cleared, the receiving end converter cuts off the direct current energy consumption device.
According to the flexible direct-current receiving-end alternating-current fault ride-through method, when a receiving-end alternating-current system is detected to have a fault, a receiving-end alternating-current fault signal of the receiving-end alternating-current system is sent to a sending-end converter through the receiving-end converter while the receiving-end converter is put into a direct-current energy consumption device. When the sending end converter receives a receiving end alternating current fault signal of a receiving end alternating current system, the sending end converter is controlled to switch a capacitor voltage average value control mode, and a timer is triggered to start timing. The sending power of the direct current side of the sending end converter is controlled based on the capacitor voltage average value control mode until the capacitor voltage of the sending end converter is in a stable state, after the capacitor voltage average value control of the sending end converter exits, the voltage reference value variable quantity output by the control returns to zero at a certain speed, the capacitor voltage is stabilized, the problem of capacitor voltage fluctuation of the sending end converter after the receiving end converter is put into a direct current energy consumption device is solved, and the stability of a sending end alternating current system is improved.
It should be understood that, although the steps in the flowcharts related to the embodiments are shown in sequence as indicated by the arrows, the steps are not necessarily executed in sequence as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least a part of the steps in the flowcharts related to the above embodiments may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of performing the steps or stages is not necessarily sequential, but may be performed alternately or alternately with other steps or at least a part of the steps or stages in other steps.
Based on the same inventive concept, the embodiment of the application also provides a flexible direct current receiving end alternating current fault ride-through system for realizing the flexible direct current receiving end alternating current fault ride-through method. The implementation scheme for solving the problem provided by the system is similar to the implementation scheme described in the above method, so that specific limitations in one or more embodiments of the flexible dc receiving ac fault ride-through system provided below can be referred to the limitations on the flexible dc receiving ac fault ride-through method above, and details are not repeated herein.
In one embodiment, as shown in fig. 8, a flexible dc receiving-end ac fault ride-through system is provided, the flexible dc receiving-end ac fault ride-through system includes a receiving-end ac system, a receiving-end converter, and a transmitting-end converter, the receiving-end ac system is connected to the receiving-end converter, the receiving-end converter and the transmitting-end converter are connected through a dc line, the receiving-end converter includes a first control module, the transmitting-end converter includes a second control module, where:
and the first control module is used for acquiring a receiving end alternating current fault signal of the receiving end alternating current system and sending the receiving end alternating current fault signal to the sending end current converter when detecting that the receiving end alternating current system sends a fault.
The second control module is used for controlling the sending end converter to be switched to a capacitor voltage average value control mode when receiving a receiving end alternating current fault signal of a receiving end alternating current system; and controlling the sending power of the direct current side of the sending end converter based on the capacitor voltage average value control mode until the capacitor voltage of the sending end converter is in a stable state.
Specifically, when the sending-end converter receives a receiving-end alternating current fault signal of a receiving-end alternating current system, the sending-end converter is controlled to be switched to a capacitor voltage average value control mode through a second control module in the second control module; the method comprises the steps that a sending end converter obtains a capacitor voltage average value and a capacitor voltage reference value, and a target sending end direct current voltage reference value of the sending end converter is determined according to the capacitor voltage average value and the capacitor voltage reference value; and controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting from the capacitor voltage average value control mode.
According to the flexible direct-current receiving end alternating current fault ride-through method system, when a receiving end alternating current system is detected to have a fault, a receiving end alternating current fault signal of the receiving end alternating current system is sent to a sending end converter through the receiving end converter; when the sending end converter receives a receiving end alternating current fault signal of a receiving end alternating current system, controlling the sending end converter to be switched to a capacitor voltage average value control mode; and controlling the sending power of the direct current side of the sending end converter based on the capacitor voltage average value control mode until the capacitor voltage of the sending end converter is in a stable state. When a receiving end alternating current system breaks down, a receiving end alternating current fault signal is sent to a sending end converter, the sending end converter is controlled to be switched to a capacitor voltage average value control mode, capacitor voltage is stabilized, the problem that capacitor voltage of the sending end converter fluctuates after the receiving end converter is put into a direct current energy consumption device is solved, and stability of the sending end alternating current system is improved.
In another embodiment, a flexible dc receiving-end ac fault ride-through system is provided, the flexible dc receiving-end ac fault ride-through system includes a receiving-end ac system, a receiving-end converter, a sending-end converter, and a sending-end ac system, the receiving-end ac system is connected to the receiving-end converter, the sending-end ac system is connected to the sending-end converter, the receiving-end converter and the sending-end converter are connected through a dc line, the receiving-end converter includes a first control module, the sending-end converter includes a second control module, a determination module, and a data acquisition module, where:
the second control module is also used for obtaining a capacitance voltage change value of the sending end converter under the condition of the fault of the receiving end alternating current system according to the difference value of the square of the capacitance voltage average value and the square of the capacitance voltage reference value;
obtaining the variation of the DC voltage reference value of the sending end converter by carrying out proportional-integral control on the variation value of the capacitor voltage;
and superposing the variation of the direct-current voltage reference value and the sending-end direct-current voltage reference value of the sending-end converter to obtain a target sending-end direct-current voltage reference value of the sending-end converter.
And the judging module is used for detecting whether the average value of the capacitor voltage is greater than the reference value of the capacitor voltage or not, and if the average value of the capacitor voltage is less than the reference value of the capacitor voltage, the fault clearing of the receiving end alternating current system is indicated.
And the data acquisition module is used for acquiring the variable quantity of the direct-current voltage reference value of the sending-end converter when the capacitor voltage average value control mode exits.
And controlling the change amount of the direct-current voltage reference value to linearly change to zero according to a set rate.
And the second control module is also used for controlling the sending end converter to be switched to a capacitor voltage average value control mode and triggering the timer to start timing when receiving an alternating current fault signal of a receiving end of the receiving end alternating current system.
The second control module is also used for controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value and acquiring the timing duration of the timer;
if the timing time reaches the preset time and the fault of the receiving end alternating current system is cleared, indicating that the capacitor voltage of the sending end converter is in a stable state; the preset time length is longer than the fault clearing time length of the receiving end alternating current system.
And the second control module is also used for triggering the timer to count again if the timing duration reaches the preset duration and the fault of the receiving end alternating current system is not cleared, executing the step of controlling the sending end converter to be switched to the capacitor voltage average value control mode until the capacitor voltage of the sending end converter is in a stable state, and exiting the capacitor voltage average value control mode.
All or part of each module in the flexible direct current receiving end alternating current fault ride-through system can be realized through software, hardware and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.
In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as shown in fig. 9. The computer device includes a processor, a memory, a communication interface, a display screen, and an input system connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The communication interface of the computer device is used for communicating with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. The computer program is executed by a processor to realize a flexible direct current receiving end alternating current fault ride-through method. The display screen of the computer equipment can be a liquid crystal display screen or an electronic ink display screen, and the input system of the computer equipment can be a touch layer covered on the display screen, a key, a track ball or a touch pad arranged on a shell of the computer equipment, an external keyboard, a touch pad or a mouse and the like.
Those skilled in the art will appreciate that the architecture shown in fig. 9 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.
In one embodiment, a computer device is further provided, which includes a memory and a processor, the memory stores a computer program, and the processor implements the steps of the above method embodiments when executing the computer program.
In an embodiment, a computer-readable storage medium is provided, on which a computer program is stored which, when being executed by a processor, carries out the steps of the above-mentioned method embodiments.
In an embodiment, a computer program product is provided, comprising a computer program which, when being executed by a processor, carries out the steps of the above-mentioned method embodiments.
It should be noted that, the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, presented data, etc.) referred to in the present application are information and data authorized by the user or sufficiently authorized by each party.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above may be implemented by hardware that is instructed by a computer program, and the computer program may be stored in a non-volatile computer-readable storage medium, and when executed, may include the processes of the embodiments of the methods described above. Any reference to memory, database, or other medium used in the embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, high-density embedded nonvolatile Memory, resistive Random Access Memory (ReRAM), magnetic Random Access Memory (MRAM), ferroelectric Random Access Memory (FRAM), phase Change Memory (PCM), graphene Memory, and the like. Volatile Memory can include Random Access Memory (RAM), external cache Memory, and the like. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM), among others. The databases referred to in various embodiments provided herein may include at least one of relational and non-relational databases. The non-relational database may include, but is not limited to, a block chain based distributed database, and the like. The processors referred to in the various embodiments provided herein may be, without limitation, general purpose processors, central processing units, graphics processors, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, or the like.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above examples only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.
Claims (10)
1. A flexible direct current receiving end alternating current fault ride-through method is characterized by comprising the following steps:
when receiving end alternating current fault signals of a receiving end alternating current system, controlling a transmitting end converter to switch to a capacitor voltage average value control mode;
acquiring a capacitor voltage average value of the sending end converter and a capacitor voltage reference value of the sending end converter;
determining a target sending end direct-current voltage reference value of the sending end converter according to the capacitor voltage average value and the capacitor voltage reference value;
and controlling the sending power of the DC side of the sending end converter according to the target sending end DC voltage reference value until the capacitor voltage of the sending end converter is in a stable state, and exiting the capacitor voltage average value control mode.
2. The method of claim 1, wherein determining a target send-side DC voltage reference for the send-side converter from the capacitor voltage average value and the capacitor voltage reference comprises:
obtaining a capacitance voltage change value of the sending end converter under the condition of the fault of the receiving end alternating current system according to the difference value of the square of the capacitance voltage average value and the square of the capacitance voltage reference value;
obtaining the variation of the direct-current voltage reference value of the sending end converter by carrying out proportional-integral control on the capacitance voltage variation value;
and superposing the variation of the direct-current voltage reference value and the sending-end direct-current voltage reference value of the sending-end converter to obtain a target sending-end direct-current voltage reference value of the sending-end converter.
3. The method of claim 1, wherein prior to the controlling the sending end inverter to switch the capacitor voltage average control mode, the method further comprises:
and detecting whether the capacitor voltage average value is larger than the capacitor voltage reference value, if so, controlling a sending end converter to switch a capacitor voltage average value control mode.
4. The method of claim 1, further comprising:
when the capacitor voltage average value control mode is exited, acquiring the variable quantity of the direct-current voltage reference value of the sending-end converter;
and controlling the change amount of the direct-current voltage reference value to linearly change to zero according to a set rate.
5. The method of claim 1, wherein controlling the sending-end converter to switch to the capacitor voltage average value control mode when receiving a receiving-end AC fault signal of a receiving-end AC system comprises:
when receiving end alternating current fault signals of a receiving end alternating current system are received, controlling a sending end converter to be switched to a capacitor voltage average value control mode, triggering a timer to start timing, and executing the step of acquiring the capacitor voltage average value of the sending end converter and the capacitor voltage reference value of the sending end converter;
the controlling the sending power of the dc side of the sending end converter according to the target sending end dc voltage reference value until the capacitor voltage of the sending end converter is in a stable state includes:
controlling the sending power of the direct current side of the sending end converter according to the target sending end direct current voltage reference value to obtain the timing duration of the timer;
if the timing time reaches a preset time and the fault of the receiving end alternating current system is cleared, indicating that the capacitor voltage of the sending end converter is in a stable state; and the preset time length is longer than the fault clearing time length of the receiving end alternating current system.
6. The method of claim 5, further comprising:
and if the timing duration reaches a preset duration and the fault of the receiving end alternating current system is not cleared, triggering the timer to count again, executing the step of controlling the sending end converter to be switched to the capacitor voltage average value control mode until the capacitor voltage of the sending end converter is in a stable state, and exiting the capacitor voltage average value control mode.
7. A flexible dc receive-side ac fault ride-through system, the system comprising a receive-side ac system, a receive-side converter, and a transmit-side converter, the receive-side ac system being connected to the receive-side converter, the receive-side converter and the transmit-side converter being connected by a dc link, the receive-side converter comprising a first control module, the transmit-side converter comprising a second control module, wherein:
the first control module is used for acquiring a receiving end alternating current fault signal of the receiving end alternating current system and sending the receiving end alternating current fault signal to the sending end current converter when detecting that the receiving end alternating current system sends a fault;
the second control module is used for controlling the sending end converter to be switched to a capacitor voltage average value control mode when receiving a receiving end alternating current fault signal of a receiving end alternating current system; and controlling the sending power of the direct current side of the sending end converter based on the capacitor voltage average value control mode until the capacitor voltage of the sending end converter is in a stable state.
8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor realizes the steps of the method of any one of claims 1 to 6 when executing the computer program.
9. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 6.
10. A computer program product comprising a computer program, characterized in that the computer program realizes the steps of the method of any one of claims 1 to 6 when executed by a processor.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210794834.9A CN115173457A (en) | 2022-07-07 | 2022-07-07 | Flexible direct current receiving end alternating current fault ride-through method, system and computer equipment |
| PCT/CN2022/127877 WO2024007488A1 (en) | 2022-07-07 | 2022-10-27 | Flexible direct-current receiving end alternating-current fault ride-through method and system, and computer device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210794834.9A CN115173457A (en) | 2022-07-07 | 2022-07-07 | Flexible direct current receiving end alternating current fault ride-through method, system and computer equipment |
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| CN115173457A true CN115173457A (en) | 2022-10-11 |
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| CN202210794834.9A Pending CN115173457A (en) | 2022-07-07 | 2022-07-07 | Flexible direct current receiving end alternating current fault ride-through method, system and computer equipment |
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| CN (1) | CN115173457A (en) |
| WO (1) | WO2024007488A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024007488A1 (en) * | 2022-07-07 | 2024-01-11 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Flexible direct-current receiving end alternating-current fault ride-through method and system, and computer device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108539796B (en) * | 2018-05-31 | 2023-08-25 | 华中科技大学 | Fault ride-through and energy dissipation control method for wind power bipolar flexible direct current power grid |
| CN114336716B (en) * | 2021-11-22 | 2023-05-26 | 中国三峡建工(集团)有限公司 | Energy dissipation method for offshore wind power system through flexible direct current grid connection |
| CN114266134A (en) * | 2021-11-22 | 2022-04-01 | 中国三峡建工(集团)有限公司 | Economical efficiency improving system for offshore wind power multi-terminal flexible direct-current power transmission energy consumption device |
| CN114499251A (en) * | 2022-01-29 | 2022-05-13 | 清华大学 | Converter system and control method thereof |
| CN115173457A (en) * | 2022-07-07 | 2022-10-11 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Flexible direct current receiving end alternating current fault ride-through method, system and computer equipment |
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- 2022-07-07 CN CN202210794834.9A patent/CN115173457A/en active Pending
- 2022-10-27 WO PCT/CN2022/127877 patent/WO2024007488A1/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024007488A1 (en) * | 2022-07-07 | 2024-01-11 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Flexible direct-current receiving end alternating-current fault ride-through method and system, and computer device |
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