CN116865332A - Flexible direct current fault ride-through control method and device, storage medium and equipment - Google Patents

Flexible direct current fault ride-through control method and device, storage medium and equipment Download PDF

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Publication number
CN116865332A
CN116865332A CN202310789851.8A CN202310789851A CN116865332A CN 116865332 A CN116865332 A CN 116865332A CN 202310789851 A CN202310789851 A CN 202310789851A CN 116865332 A CN116865332 A CN 116865332A
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fault
integral coefficient
voltage
flexible direct
direct current
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CN116865332B (en
Inventor
唐王倩云
蔡希鹏
周保荣
张野
杨子千
李俊杰
袁豪
李诗旸
郭知非
田宝烨
黄东启
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CSG Electric Power Research Institute
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CSG Electric Power Research Institute
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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
    • 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
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00001—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by the display of information or by user interaction, e.g. supervisory control and data acquisition systems [SCADA] or graphical user interfaces [GUI]
    • 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
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • H02J13/00016—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using a wired telecommunication network or a data transmission bus
    • H02J13/00017—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using a wired telecommunication network or a data transmission bus using optical fiber
    • 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
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • H02J13/00022—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using wireless data transmission
    • H02J13/00024—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using wireless data transmission by means of mobile telephony
    • 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
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • H02J13/00022—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using wireless data transmission
    • H02J13/00026—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using wireless data transmission involving a local wireless network, e.g. Wi-Fi, ZigBee or Bluetooth
    • 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
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/48—Controlling the sharing of the in-phase component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Human Computer Interaction (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The application provides a flexible direct current fault ride-through control method, a device, a storage medium and equipment. The method comprises the following steps: acquiring the alternating-current side end voltage of a converter valve and the output power of a flexible direct-current converter station; if the voltage of the alternating-current side end is smaller than the low-voltage crossing threshold value, triggering low-voltage crossing and acquiring an active power instruction value in a fault period; determining a second integral coefficient during the fault according to the difference value between the active power instruction value and the outgoing power; switching the integral coefficient of the voltage outer loop controller from the first integral coefficient before failure to the second integral coefficient; the difference value of the active power instruction value and the outgoing power in the fault period and the second integral coefficient are in a negative correlation relationship; acquiring the voltage of an alternating-current side end in real time; if the real-time value of the voltage at the alternating-current side end is higher than the low-voltage crossing threshold value, fault recovery is executed, and the integral coefficient of the voltage outer loop controller is switched to the first integral coefficient. The application can improve the stability of the island system from which new energy is sent out by flexible direct current.

Description

Flexible direct current fault ride-through control method and device, storage medium and equipment
Technical Field
The present application relates to the field of power system control technologies, and in particular, to a method and apparatus for controlling flexible dc fault ride through, a storage medium, and a computer device.
Background
Accelerating the construction of large-scale wind-electricity photovoltaic bases with deserts, gobi and desert areas as important points is a great strategic requirement for the construction of the current electric power system. The large-scale pure new energy base has large installed capacity and wide distribution area, and a flexible direct current island sending mode is often adopted. The conventional flexible direct current VF control (constant alternating current voltage/constant frequency control) mode fault ride through strategy is mainly used for offshore wind power transmission systems. And the large-scale pure new energy base is sent out of the system, the probability of faults is higher, and the stability requirement on the system at the sending end after the faults is higher.
In order to ensure the transient stability of the large-scale pure new energy base transmitter, the transmitter needs to actively reduce the power and slow down the power recovery rate during the fault period. However, existing flexible direct current uses a method of freezing the outer loop controller during a fault in order to prevent saturation of the integral control during the fault. For large-scale pure new energy base end-transmitting systems, the end-transmitting systems cannot be provided with power supplies capable of adjusting voltage in transient processes. This easily causes a problem of voltage stabilization after a large new energy base terminal system fails. If the outer ring controller is controlled normally, when the fault is deeper, the transient stability problem is caused by overlarge outer ring deviation and too fast action.
Disclosure of Invention
The embodiment of the application provides a flexible direct current fault ride-through control method, a device, a storage medium and equipment, which can improve system stability.
In a first aspect, the present application provides a flexible direct current fault ride through control method applied to a flexible direct current converter station in a system from which pure new energy is sent out through a flexible direct current island, the method comprising:
acquiring alternating-current side end voltage of a converter valve and the output power of the flexible direct-current converter station;
if the voltage of the alternating-current side end is smaller than a low-voltage crossing threshold value, triggering low-voltage crossing and acquiring an active power instruction value in a fault period;
determining a second integral coefficient during a fault according to the difference value between the active power instruction value and the output power;
switching the integral coefficient of the voltage outer loop controller from a first integral coefficient before failure to the second integral coefficient; the first integral coefficient is larger than the second integral coefficient, and the difference value between the active power instruction value and the output power in the fault period and the second integral coefficient are in negative correlation;
acquiring the voltage of an alternating-current side end in real time;
and if the real-time value of the alternating-current side terminal voltage is higher than the low-voltage crossing threshold value, fault recovery is executed, and the integral coefficient of the voltage outer loop controller is switched to the first integral coefficient.
In one embodiment, the acquiring the active power command value during the fault includes:
acquiring the output power of the flexible direct current converter station within a preset time before triggering low voltage ride through;
calculating an average value of the output power of the flexible direct current converter station within the preset time period;
the average value is determined as an active power command value during the fault.
In one embodiment, the predetermined time period is greater than or equal to 60s.
In one embodiment, during the low voltage ride through, the method further comprises:
the method comprises the steps of regularly obtaining the output power of the flexible direct current converter station;
and dynamically adjusting the second integral coefficient according to the real-time value of the output power of the flexible direct current converter station.
In one embodiment, after determining the first integral coefficient according to the difference between the active power command value and the output power during the low voltage ride through, the method further includes:
calculating a second proportional coefficient during the fault according to the first integral coefficient, the second integral coefficient and the first proportional coefficient of the voltage outer loop controller before the fault;
and switching the scaling factor of the voltage outer loop controller from the first scaling factor to the second scaling factor until the first scaling factor is switched back when fault recovery is performed.
In a second aspect, the present application provides a flexible dc fault ride through control device applied to a flexible dc converter station in a system from which pure new energy is sent out via a flexible dc island, the device comprising:
the first acquisition module is used for acquiring alternating-current side terminal voltage of the converter valve and the output power of the flexible direct-current converter station;
the low voltage ride through module is used for sending low voltage ride through when the voltage of the alternating current side end is smaller than a low voltage ride through threshold value, and acquiring an active power instruction value in a fault period;
the first determining module is used for determining a second integral coefficient during the fault according to the difference value between the active power instruction value and the output power;
the first switching module is used for switching the integral coefficient of the voltage outer loop controller from the first integral coefficient before failure to the second integral coefficient; the first integral coefficient is larger than the second integral coefficient, and the difference value between the active power instruction value and the output power in the fault period and the second integral coefficient are in negative correlation;
the second acquisition module is used for acquiring the alternating-current side terminal voltage in real time;
and the fault recovery module is used for executing fault recovery when the real-time value of the alternating-current side terminal voltage is higher than the low-voltage crossing threshold value, and switching the integral coefficient of the voltage outer loop controller to the first integral coefficient.
In one embodiment, the low voltage ride through module comprises:
the power acquisition unit is used for acquiring the output power of the flexible direct current converter station within a preset time before triggering the low voltage ride through;
the calculating unit is used for calculating the average value of the output power of the flexible direct current converter station in the preset time length;
and the command value configuration unit is used for determining the average value as the active power command value during the fault.
In one embodiment, the apparatus further comprises:
the power monitoring module is used for regularly acquiring the output power of the flexible direct current converter station during the low voltage ride through period;
and the dynamic adjustment module is used for dynamically adjusting the second integral coefficient according to the real-time value of the output power of the flexible direct current converter station during the low voltage ride through period.
In a third aspect, the present application provides a storage medium having stored therein computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of the flexible direct current fault ride through control method as described in any of the embodiments above.
In a fourth aspect, the present application provides a computer device comprising: one or more processors, and memory;
the memory has stored therein computer readable instructions which, when executed by the one or more processors, perform the steps of the flexible direct current fault ride-through control method as described in any of the embodiments above.
From the above technical solutions, the embodiment of the present application has the following advantages:
the flexible direct current fault ride-through control method, the device, the storage medium and the computer equipment provided by the application monitor the alternating current side end voltage of the converter valve and the output power of the flexible direct current converter station, trigger the low voltage ride-through process when the alternating current side end voltage is smaller than the low voltage ride-through threshold value, determine the second integral coefficient of the voltage outer loop controller during the fault period according to the difference value of the active power command value and the output power during the fault period, switch the second integral coefficient, reduce the integral coefficient of the voltage outer loop controller, and switch the integral coefficient of the voltage outer loop controller back to the first integral coefficient before the fault when the real-time value of the alternating current side end voltage is higher than the low voltage ride-through threshold value and enters the fault recovery process, so that the outer loop of the flexible direct current converter station maintains certain integral capacity during the fault period, and meanwhile, the current command value is prevented from being influenced by voltage deviation to be changed fast and deviate from a steady state value too, and transient stability of the system is improved.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the application, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.
Fig. 1 is a schematic diagram of an application scenario of a flexible dc fault ride-through control method in one embodiment;
FIG. 2 is a flow chart of a flexible DC fault ride-through control method according to one embodiment;
FIG. 3 is a schematic diagram showing a correlation between a difference between an active command value and an output power and a second integral coefficient in an embodiment;
FIG. 4 is a schematic diagram of fault ride-through control logic in one embodiment;
FIG. 5 is a flowchart illustrating steps for obtaining an active power command value during a fault in one embodiment;
FIG. 6 is a block diagram of a flexible DC fault ride-through control device according to one embodiment;
FIG. 7 is an internal block diagram of a computer device, in one embodiment.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Aiming at the island sending-out system, the conventional flexible direct current adopts a VF control mode, namely a given frequency generation control phase, and d-axis and q-axis control branches are divided into an outer ring and an inner ring for control. In the existing flexible direct current fault ride-through control method, after a low voltage ride-through signal is detected during fault ride-through, an outer ring controller is frozen, output current limits current amplitude according to voltage drop degree, and equal proportion distribution is carried out according to the magnitude of an output d-axis current command value and a q-axis current command value of an outer ring, so that a d-axis current command value and a q-axis current command after amplitude limiting are obtained. However, freezing the outer ring controller can cause that the transmitting end system does not have a power supply capable of adjusting voltage in the transient process, which easily causes the problem of voltage stability after the transmitting end system fails, and when the failure is deeper, the problem of transient stability is caused by overlarge outer ring deviation and too fast action.
Based on the above problems, the embodiment of the application provides a flexible direct current fault ride through control method, which is applied to a flexible direct current converter station in a system where pure new energy is sent out through a flexible direct current island, wherein the pure new energy only comprises a new energy generator set, for example, only comprises photovoltaic power generation, or comprises photovoltaic power generation, wind power discharge and the like. The embodiment of the application is illustrated by taking the scene shown in fig. 1 as an example, the photovoltaic power generation base transmits through long-line impedance, power transmission is realized through the flexible direct current converter, three-phase ground faults occur at the bus of the port of the flexible direct current converter, and the photovoltaic power generation base adopts a power reduction control strategy to carry out fault ride-through control.
As shown in fig. 2, an embodiment of the present application provides a flexible direct current fault ride through control method, where the method includes:
step S201, obtaining an ac side terminal voltage of the converter valve and an output power of the flexible dc converter station.
The converter valve is core equipment of flexible direct current transmission engineering, and mainly comprises IGBT, control driving unit, cooling system, saturation reactor, electric capacity, resistance etc.. Unlike the thyristor of semi-controlled device used in conventional DC power transmission engineering, the soft DC engineering converter valve adopts fully-controlled IGBT to realize the conversion of AC and DC by controlling the on/off of the IGBT. The alternating-current side end voltage of the converter valve and the output power of the flexible direct-current converter station are obtained through real-time measurement of the detection equipment.
Step S202, if the voltage at the AC side terminal is smaller than the low voltage ride through threshold, triggering the low voltage ride through to obtain the active power command value during the fault period
The low voltage crossing threshold is a preset voltage threshold for judging whether the flexible direct current end needs to enter a low voltage crossing process, and when the voltage of the alternating current side end is smaller than the low voltage crossing threshold, the low voltage crossing process is not needed, and an active power instruction value in a fault period is obtained
Step S203, according to the active power fingerLet valueWith the power P of the outgoing e Is a difference deltaP of (1) e Determining a second integral coefficient k during a fault iac2 。
Referring to FIG. 3, active power command values during a fault are shownDifference deltap from the outgoing power P e And a second integral coefficient k iac2 In negative correlation, i.e. DeltaP e The larger the second integral coefficient k iac2 The smaller.
Step S204, the integral coefficient of the voltage outer loop controller is calculated from the first integral coefficient k before failure iac1 Switching to the second integral coefficient k iac2 。
Wherein the first integral coefficient is larger than the second integral coefficient, and the integral coefficient is switched to the second integral coefficient k iac2 The integral coefficient of the voltage outer loop controller is reduced, so that the change speed of the current command value affected by voltage deviation during faults is reduced.
Step S205, the AC side terminal voltage is obtained in real time.
The ac side terminal voltage needs to be obtained in real time during the low voltage ride through to determine whether to end the low voltage ride through and perform fault recovery.
Step S206, if the real-time value of the AC side voltage is higher than the low voltage crossing threshold, performing fault recovery and switching the integral coefficient of the voltage outer loop controller to the first integral coefficient k iac1 。
Switching the integral coefficient of the voltage outer loop controller back to the first integral coefficient k before failure while entering the failure recovery process iac1 。
Referring to fig. 4, the fault-ride-through control logic in the present embodiment is shown, in normal condition, lvrt=0, and the integral coefficient of the flexible dc voltage outer loop controller adopts the first integral coefficient k iac1 . In fault, lvrt=1, and the integral coefficient of the flexible DC voltage outer loop controller adopts a second integral systemNumber k iac2 . The outer loop voltage deviation is controlled by proportional integral to generate a current commandAndthen generates final current instruction +.>And->
In this embodiment, by monitoring the ac side terminal voltage of the converter valve and the output power of the flexible dc converter station, triggering the low voltage ride through process when the ac side terminal voltage is less than the low voltage ride through threshold, determining the second integral coefficient k of the voltage outer loop controller during the fault according to the difference between the active power command value and the output power during the fault ia Switching is carried out, the integral coefficient of the voltage outer loop controller is reduced, and when the low voltage ride through is ended and the fault recovery process is carried out until the real-time value of the voltage at the alternating current side end is higher than the low voltage ride through threshold value, the integral coefficient of the voltage outer loop controller is switched back to the first integral coefficient k before the fault iac1 The outer ring of the flexible direct current converter station keeps certain integral capacity during the fault period, meanwhile, the phenomenon that the current command value is influenced by voltage deviation to change rapidly and deviate from the steady-state value too much is avoided, and the transient stability of the system is improved.
As shown in fig. 5, in one embodiment, the acquiring the active power command value during the fault includes:
step S501, obtaining the output power of a flexible direct current converter station within a preset time period before triggering low voltage ride through;
step S502, calculating an average value of the output power of the flexible direct current converter station within a preset time period;
step S503, the average value is determined as the active power command value during the fault.
In this embodiment, an average value of the output power triggering a preset duration between the low voltage crossings is used as an active power command value during the fault, that is, a steady state value before the fault is used as a reference value, and errors caused by measurement errors and normal fluctuation in the running process are reduced by taking the average value, so that the system stability in the low voltage crossing process is improved. In one embodiment, the predetermined time period is greater than or equal to 60 seconds.
In one embodiment, during the low voltage ride through, the flexible direct current fault ride through control method further comprises:
the method comprises the steps of regularly obtaining the output power of a flexible direct current converter station;
and dynamically adjusting the second integral coefficient according to the real-time value of the output power of the flexible direct current converter station.
In this embodiment, if the output power changes during the low voltage ride through period, the first integral coefficient is dynamically adjusted, i.e. the first integral coefficient is dynamically adjusted according to the difference between the active power command value and the real-time output power value.
In one embodiment, after determining the first integral coefficient according to the difference between the active power command value and the output power during the low voltage ride through, the flexible direct current fault ride through control method further includes:
according to a first integral coefficient k iac1 Second integral coefficient k iac2 First scaling factor k of pre-fault voltage outer loop controller p1 Calculating a second scaling factor k during the fault p2 ；
The proportionality coefficient of the voltage outer loop controller is changed from the first proportionality coefficient k p1 Switching to the second scaling factor k p2 Switching back to the first proportional coefficient k until fault recovery is performed p1 。
Wherein the second scaling factor is calculated according to the following formula:
in this embodiment, during the low voltage ride through period, the integral coefficient and the scaling factor of the voltage outer loop controller are adjusted at the same time, the scaling factor affects the variation degree of the current command value along with the deviation of the voltage command value, so that the current command value can be restricted in an auxiliary manner so as not to deviate from the steady-state value too much, and the fault recovery process is switched back to the first scaling factor before the fault.
It should be understood that, although the steps in the flowcharts related to the embodiments described above are sequentially shown as indicated by arrows, these steps are not necessarily sequentially performed in the order indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in the flowcharts described in the above embodiments may include a plurality of steps or a plurality of stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of the steps or stages is not necessarily performed sequentially, but may be performed alternately or alternately with at least some of the other steps or stages.
The flexible direct current fault ride through control device provided by the embodiment of the application is described below, and the flexible direct current fault ride through control device described below and the flexible direct current fault ride through control method described above can be referred to correspondingly.
As shown in fig. 6, an embodiment of the present application provides a flexible dc fault ride-through control device 600 applied to a flexible dc converter station in a system where pure new energy is sent out through a flexible dc island, where the device includes:
the first obtaining module 601 is configured to obtain an ac side terminal voltage of a converter valve and an output power of the flexible dc converter station;
the low voltage ride through module 602 is configured to send out low voltage ride through when the ac side voltage is less than a low voltage ride through threshold value, and obtain an active power command value during a fault period;
a first determining module 603, configured to determine a second integral coefficient during a fault according to a difference between the active power command value and the outgoing power;
a first switching module 604, configured to switch an integration coefficient of the voltage outer loop controller from a first integration coefficient before a fault to the second integration coefficient; the first integral coefficient is larger than the second integral coefficient, and the difference value between the active power instruction value and the output power in the fault period and the second integral coefficient are in negative correlation;
a second obtaining module 605, configured to obtain an ac side terminal voltage in real time;
the fault recovery module 606 is configured to perform fault recovery when the real-time value of the ac side terminal voltage is higher than the low voltage crossing threshold, and switch the integral coefficient of the voltage outer loop controller to the first integral coefficient.
In one embodiment, the low voltage ride through module comprises:
the power acquisition unit is used for acquiring the output power of the flexible direct current converter station within a preset time before triggering the low voltage ride through;
the calculating unit is used for calculating the average value of the output power of the flexible direct current converter station in the preset time length;
and the command value configuration unit is used for determining the average value as the active power command value during the fault.
In one embodiment, the apparatus further comprises:
the power monitoring module is used for regularly acquiring the output power of the flexible direct current converter station during the low voltage ride through period;
and the dynamic adjustment module is used for dynamically adjusting the second integral coefficient according to the real-time value of the output power of the flexible direct current converter station during the low voltage ride through period.
In one embodiment, the apparatus further comprises:
the second calculation module is used for calculating a second proportionality coefficient during the fault according to the first integration coefficient, the second integration coefficient and the first proportionality coefficient of the voltage outer loop controller before the fault during the low voltage crossing;
and the second switching module is used for switching the proportional coefficient of the voltage outer loop controller from the first proportional coefficient to the second proportional coefficient until the first proportional coefficient is switched back when fault recovery is executed.
The above-mentioned division of each module in the flexible dc fault ride-through control device is only used for illustration, and in other embodiments, the flexible dc fault ride-through control device may be divided into different modules according to the needs, so as to complete all or part of the functions of the flexible dc fault ride-through control device. The modules in the flexible direct current fault ride-through control device can be all or partially realized by software, hardware and a combination thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.
In one embodiment, the present application also provides a storage medium having stored therein computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of:
acquiring alternating-current side end voltage of a converter valve and the output power of the flexible direct-current converter station;
if the voltage of the alternating-current side end is smaller than a low-voltage crossing threshold value, triggering low-voltage crossing and acquiring an active power instruction value in a fault period;
determining a second integral coefficient during a fault according to the difference value between the active power instruction value and the output power;
switching the integral coefficient of the voltage outer loop controller from a first integral coefficient before failure to the second integral coefficient; the first integral coefficient is larger than the second integral coefficient, and the difference value between the active power instruction value and the output power in the fault period and the second integral coefficient are in negative correlation;
acquiring the voltage of an alternating-current side end in real time;
and if the real-time value of the alternating-current side terminal voltage is higher than the low-voltage crossing threshold value, fault recovery is executed, and the integral coefficient of the voltage outer loop controller is switched to the first integral coefficient.
In one embodiment, the computer readable instructions when executed by the processor further implement the steps of:
acquiring the output power of the flexible direct current converter station within a preset time before triggering low voltage ride through;
calculating an average value of the output power of the flexible direct current converter station within the preset time period;
the average value is determined as an active power command value during the fault.
In one embodiment, the computer readable instructions when executed by the processor further implement the steps of:
the method comprises the steps of regularly obtaining the output power of the flexible direct current converter station;
and dynamically adjusting the second integral coefficient according to the real-time value of the output power of the flexible direct current converter station.
In one embodiment, the computer readable instructions when executed by the processor further implement the steps of:
calculating a second proportional coefficient during the fault according to the first integral coefficient, the second integral coefficient and the first proportional coefficient of the voltage outer loop controller before the fault;
and switching the scaling factor of the voltage outer loop controller from the first scaling factor to the second scaling factor until the first scaling factor is switched back when fault recovery is performed.
In one embodiment, the present application also provides a computer device having computer readable instructions stored therein, which when executed by the one or more processors, perform the steps of:
acquiring alternating-current side end voltage of a converter valve and the output power of the flexible direct-current converter station;
if the voltage of the alternating-current side end is smaller than a low-voltage crossing threshold value, triggering low-voltage crossing and acquiring an active power instruction value in a fault period;
determining a second integral coefficient during a fault according to the difference value between the active power instruction value and the output power;
switching the integral coefficient of the voltage outer loop controller from a first integral coefficient before failure to the second integral coefficient; the first integral coefficient is larger than the second integral coefficient, and the difference value between the active power instruction value and the output power in the fault period and the second integral coefficient are in negative correlation;
acquiring the voltage of an alternating-current side end in real time;
and if the real-time value of the alternating-current side terminal voltage is higher than the low-voltage crossing threshold value, fault recovery is executed, and the integral coefficient of the voltage outer loop controller is switched to the first integral coefficient.
In one embodiment, the processor, when executing the computer-readable instructions, further performs the steps of:
acquiring the output power of the flexible direct current converter station within a preset time before triggering low voltage ride through;
calculating an average value of the output power of the flexible direct current converter station within the preset time period;
the average value is determined as an active power command value during the fault.
In one embodiment, the processor, when executing the computer-readable instructions, further performs the steps of:
the method comprises the steps of regularly obtaining the output power of the flexible direct current converter station;
and dynamically adjusting the second integral coefficient according to the real-time value of the output power of the flexible direct current converter station.
In one embodiment, the processor, when executing the computer-readable instructions, further performs the steps of:
calculating a second proportional coefficient during the fault according to the first integral coefficient, the second integral coefficient and the first proportional coefficient of the voltage outer loop controller before the fault;
and switching the scaling factor of the voltage outer loop controller from the first scaling factor to the second scaling factor until the first scaling factor is switched back when fault recovery is performed.
In one embodiment, a computer device is provided, which may be a terminal, and the internal structure of which may be as shown in fig. 7. The computer device includes a processor, a memory, a communication interface, a display screen, and an input device 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 includes a non-volatile 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 the operating system and computer programs in the non-volatile storage media. The communication interface of the computer device is used for carrying out wired or wireless communication with an external terminal, and the wireless mode can be realized through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. The computer program, when executed by a processor, implements a flexible direct current fault ride-through control method. The display screen of the computer equipment can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment can be a touch layer covered on the display screen, can also be keys, a track ball or a touch pad arranged on the shell of the computer equipment, and can also be an external keyboard, a touch pad or a mouse and the like.
It will be appreciated by those skilled in the art that the structure shown in FIG. 7 is merely a block diagram of some of the structures associated with the present inventive arrangements and is not limiting of the computer device to which the present inventive arrangements may be applied, and that a particular computer device may include more or fewer components than shown, or may combine some of the components, or have a different arrangement of components.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, database, or other medium used in 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 (Magnetoresistive Random Access Memory, MRAM), ferroelectric Memory (Ferroelectric Random Access Memory, FRAM), phase change Memory (Phase Change Memory, PCM), graphene Memory, and the like. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, and the like. By way of illustration, and not limitation, RAM can be in the form of a variety of forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), and the like. The databases referred to in the embodiments provided herein may include at least one of a relational database and a non-relational database. The non-relational database may include, but is not limited to, a blockchain-based distributed database, and the like. The processor referred to in the embodiments provided in the present application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, or the like, but is not limited thereto.
Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present specification, each embodiment is described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and may be combined according to needs, and the same similar parts may be referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The flexible direct current fault ride through control method is characterized by being applied to a flexible direct current converter station in a system from which pure new energy is sent out through a flexible direct current island, and comprises the following steps:
acquiring alternating-current side end voltage of a converter valve and the output power of the flexible direct-current converter station;
if the voltage of the alternating-current side end is smaller than a low-voltage crossing threshold value, triggering low-voltage crossing and acquiring an active power instruction value in a fault period;
determining a second integral coefficient during a fault according to the difference value between the active power instruction value and the output power;
switching the integral coefficient of the voltage outer loop controller from a first integral coefficient before failure to the second integral coefficient; the first integral coefficient is larger than the second integral coefficient, and the difference value between the active power instruction value and the output power in the fault period and the second integral coefficient are in negative correlation;
acquiring the voltage of an alternating-current side end in real time;
and if the real-time value of the alternating-current side terminal voltage is higher than the low-voltage crossing threshold value, fault recovery is executed, and the integral coefficient of the voltage outer loop controller is switched to the first integral coefficient.
2. The flexible direct current fault ride-through control method according to claim 1, wherein the acquiring the active power command value during the fault includes:
acquiring the output power of the flexible direct current converter station within a preset time before triggering low voltage ride through;
calculating an average value of the output power of the flexible direct current converter station within the preset time period;
the average value is determined as an active power command value during the fault.
3. The flexible direct current fault ride-through control method according to claim 2, wherein the preset time period is greater than or equal to 60s.
4. The flexible direct current fault ride-through control method of claim 1, wherein during low voltage ride-through, the method further comprises:
the method comprises the steps of regularly obtaining the output power of the flexible direct current converter station;
and dynamically adjusting the second integral coefficient according to the real-time value of the output power of the flexible direct current converter station.
5. The flexible direct current fault ride through control method according to any one of claims 1 to 4, wherein, during low voltage ride through, after performing determination of a second integral coefficient from a difference between the active power command value and the outgoing power, further comprising:
calculating a second proportional coefficient during the fault according to the first integral coefficient, the second integral coefficient and the first proportional coefficient of the voltage outer loop controller before the fault;
and switching the scaling factor of the voltage outer loop controller from the first scaling factor to the second scaling factor until the first scaling factor is switched back when fault recovery is performed.
6. The utility model provides a flexible direct current fault ride through controlling means which characterized in that is applied to the flexible direct current converter station in pure new forms of energy via flexible direct current island delivery system, said device includes:
the first acquisition module is used for acquiring alternating-current side terminal voltage of the converter valve and the output power of the flexible direct-current converter station;
the low voltage ride through module is used for sending low voltage ride through when the voltage of the alternating current side end is smaller than a low voltage ride through threshold value, and acquiring an active power instruction value in a fault period;
the first determining module is used for determining a second integral coefficient during the fault according to the difference value between the active power instruction value and the output power;
the first switching module is used for switching the integral coefficient of the voltage outer loop controller from the first integral coefficient before failure to the second integral coefficient; the first integral coefficient is larger than the second integral coefficient, and the difference value between the active power instruction value and the output power in the fault period and the second integral coefficient are in negative correlation;
the second acquisition module is used for acquiring the alternating-current side terminal voltage in real time;
and the fault recovery module is used for executing fault recovery when the real-time value of the alternating-current side terminal voltage is higher than the low-voltage crossing threshold value, and switching the integral coefficient of the voltage outer loop controller to the first integral coefficient.
7. The flexible direct current fault ride-through control device of claim 6, wherein the low voltage ride-through module comprises:
the power acquisition unit is used for acquiring the output power of the flexible direct current converter station within a preset time before triggering the low voltage ride through;
the calculating unit is used for calculating the average value of the output power of the flexible direct current converter station in the preset time length;
and the command value configuration unit is used for determining the average value as the active power command value during the fault.
8. The flexible direct current fault ride-through control device of claim 6, further comprising:
the power monitoring module is used for regularly acquiring the output power of the flexible direct current converter station during the low voltage ride through period;
and the dynamic adjustment module is used for dynamically adjusting the second integral coefficient according to the real-time value of the output power of the flexible direct current converter station during the low voltage ride through period.
9. A storage medium, characterized by: the storage medium having stored therein computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of the flexible direct current fault ride-through control method of any of claims 1 to 5.
10. A computer device, comprising: one or more processors, and memory;
the memory has stored therein computer readable instructions which, when executed by the one or more processors, perform the steps of the flexible direct current fault ride-through control method of any of claims 1 to 5.
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