CN113794208A - Control method for reducing high-voltage cascade SVG low-voltage ride-through off-line - Google Patents

Control method for reducing high-voltage cascade SVG low-voltage ride-through off-line Download PDF

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CN113794208A
CN113794208A CN202111014031.9A CN202111014031A CN113794208A CN 113794208 A CN113794208 A CN 113794208A CN 202111014031 A CN202111014031 A CN 202111014031A CN 113794208 A CN113794208 A CN 113794208A
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voltage
low
penetration
grid
phase
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CN113794208B (en
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王璐
霍利杰
杨忠浩
李芳芳
刘猛
虞剑文
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Nanjing Zhirui Energy Internet Research Institute Co ltd
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Nanjing Zhirui Energy Internet Research Institute Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • 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
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/48—Controlling the sharing of the in-phase component
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/50—Controlling the sharing of the out-of-phase component
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • 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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/10—Flexible AC transmission systems [FACTS]
    • 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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Inverter Devices (AREA)

Abstract

The invention discloses a control method for reducing high-voltage cascade SVG low-voltage ride through off-line, and relates to the technical field of power equipment. The method comprises the steps of detecting the voltage of a power grid, locking the phase of the voltage of the power grid, obtaining the ratio of the active component of the voltage to the rated voltage, judging the in-out low-penetration logic, processing the angular frequency sliding average of the power grid, exiting from the low-penetration lock drive logic to avoid overcurrent and off-grid logic, and controlling the balance of the voltage of a bus under asymmetrical drop. At the moment of grid voltage drop, the method can quickly and effectively detect low-voltage penetration and send out reactive current corresponding to the grid voltage to support the grid, so that when the grid exits from a low-voltage penetration state, the problem of low-voltage penetration and grid disconnection is effectively reduced, the grid-connected operation capacity of the device is greatly improved, and the safety and reliability of new energy accessed to the grid are ensured.

Description

Control method for reducing high-voltage cascade SVG low-voltage ride-through off-line
Technical Field
The invention belongs to the technical field of power equipment, and particularly relates to a control method for reducing high-voltage cascade SVG low-voltage ride-through off-line.
Background
In order to reduce the emission of greenhouse gases, more and more clean energy sources are connected to a power grid, such as clean energy sources of wind power, photovoltaic and the like, and the energy sources can be connected to the power grid only by power conversion through a power electronic device, however, wind power and illumination have randomness and instability, and the power electronic device has the characteristics of nonlinearity and small inertia, so that the voltage of the power grid is distorted and unstable. Compared with a passive compensator, the static synchronous compensator (SVG) has the advantages of continuous power regulation, quick dynamic response and the like, and in addition, the cascaded SVG is often used for a 1KV-50KV medium-voltage level power system, and because of the advantages of no transformer, multiple levels and modularization, the high-voltage cascaded star configuration SVG is very suitable for the scene.
However, the low voltage ride through capability is a key problem of the grid-connected inverter device, and the device is required to be capable of keeping the grid-connected state without disconnection in a certain grid voltage drop period and injecting reactive current with corresponding voltage amplitude into the grid.
Disclosure of Invention
In order to solve the problem that the high-voltage cascade SVG is easy to be off-line during low-voltage ride through, the invention provides a control method for reducing the off-line of the high-voltage cascade SVG during low-voltage ride through.
In order to solve the technical problems, the invention is realized by the following technical scheme:
the invention relates to a control method for reducing high-voltage cascade SVG low-voltage ride through off-line, which specifically comprises the following steps:
(1) sampling the voltage of a power grid, carrying out phase tracking on the voltage of the power grid by a phase-locked loop, decomposing the voltage to obtain an active voltage component Vd and a reactive voltage component, and decomposing the current to obtain an active current component and a reactive current component;
(2) judging whether the active voltage component Vd obtained by the phase-locked loop is greater than the set voltage value of the sliding filtering of the enabling calculation angular frequency, if so, carrying out the sliding filtering processing on the grid voltage angular frequency W obtained by the phase locking to obtain the sliding average filtering angular frequency WMafUnder the condition of restraining asymmetric drop, a phase-locked loop cannot work when the phase-locked loop is in zero penetration and 2-order harmonic pulsation components in active and reactive components of the voltage of a power grid, and a reference phase is provided for reactive current;
(3) when the Vd is smaller than a low penetration setting value, entering low penetration, sending corresponding reactive current according to the voltage drop depth of the power grid, timing the low penetration state entering time, and judging whether the duration time of the low penetration state exceeds the preset low penetration time; when the Vd is not less than the low penetration setting value, judging whether the Vd is greater than an exit low penetration setting value;
(4) when the Vd is not greater than the exit low penetration setting value, entering low penetration, sending corresponding reactive current according to the voltage drop depth of the power grid, timing the low penetration state entering time, judging whether the low penetration state duration time exceeds the low penetration preset time, and jumping to the step (6) when the entering low penetration time exceeds; when the Vd is larger than the exit low-penetration setting value, judging whether the high-voltage cascaded SVG is in a low-penetration state;
(5) when the high-voltage cascaded SVG is in a low-penetration state, blocking a set cycle driving pulse, after the driving is recovered, switching to the step (1) to continue to sample the voltage of the power grid, and executing the steps (1) - (4) again; when the high-voltage cascaded SVG is not in a low-voltage state, directly switching to the step (1) to sample the voltage of the power grid, and similarly executing the steps (1) - (4) again;
(6) and (3) when the low penetration time exceeds in the step (4), the high-voltage cascaded SVG is disconnected, otherwise, the step (1) is carried out to continue to sample the voltage of the power grid, and the steps (1) - (4) are carried out again.
Further, the method for acquiring and detecting the grid voltage in the step (1) specifically comprises the following steps: and an AD (analog-to-digital) conversion module is adopted to collect the three-phase power grid voltage into the controller and carry out data operation on the three-phase power grid voltage.
Further, the data operation specifically includes: clark, Park coordinate transformation and phase-locked loop calculation.
Further, when the low penetration is performed in the steps (3) and (4), the corresponding reactive current is output according to the standard to support the power grid, and the method specifically comprises the following steps: the method comprises the steps of storing a current reactive power set value before entering low penetration, determining the reactive current required to be output by the high-voltage cascaded SVG according to the ratio of the grid voltage active component Vd obtained by phase locking to the rated grid voltage when entering low penetration, and recovering the reactive current set when entering low penetration when exiting low penetration.
Further, the grid voltage drop in steps (3) and (4) is an asymmetric drop, and the bus voltage balance control is realized under the asymmetric drop, specifically including: under the condition of asymmetric drop, the voltage of each phase of the high-voltage cascaded SVG bus can be unbalanced, and the bus overvoltage is restrained by adopting negative sequence current control.
The invention has the following beneficial effects:
1. the control method for reducing the low voltage ride through and off-grid of the high voltage cascaded SVG can effectively reduce the problem of fault and off-grid of the device in low voltage ride through, greatly improve the grid-connected operation capability of the device and ensure the safety and reliability of new energy accessed into a power grid.
Of course, it is not necessary for any product in which the invention is practiced to achieve all of the above-described advantages at the same time.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a flowchart of a control method for reducing the off-line of the high-voltage cascaded SVG low voltage ride through according to the present invention.
Fig. 2 is a topological diagram of a high-voltage cascaded SVG main circuit according to the present invention.
Fig. 3 is a block diagram of a high-voltage cascaded SVG three-layer hierarchical control according to the present invention.
Fig. 4 is a block diagram of voltage processing control of the high-voltage cascaded SVG bus according to the present invention.
Fig. 5 is a schematic block diagram of a high-voltage cascaded SVG phase-locked loop according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Examples
Referring to fig. 1, the present invention is a control method for reducing high-voltage cascade SVG low-voltage ride through off-line, which specifically includes the following steps:
(1) sampling the voltage of a power grid, carrying out phase tracking on the voltage of the power grid by a phase-locked loop, decomposing the voltage to obtain an active voltage component Vd and a reactive voltage component, and decomposing the current to obtain an active current component and a reactive current component;
(2) judging whether the active voltage component Vd obtained by the phase-locked loop is greater than the set voltage value of the sliding filtering of the enabling calculation angular frequency, if Vd is greater than the set voltage value of the sliding filtering of the enabling calculation angular frequency, performing sliding filtering processing on the grid voltage angular frequency W obtained by phase locking to obtain the sliding average filtering angular frequency WMafUnder the condition of restraining asymmetric drop, a phase-locked loop cannot work when the phase-locked loop is in zero penetration and 2-order harmonic pulsation components in active and reactive components of the voltage of a power grid, and a reference phase is provided for reactive current;
(3) when Vd is smaller than a low-penetration setting value, entering low penetration, sending corresponding reactive current according to the voltage drop depth of the power grid, timing the low-penetration state entering time, and judging whether the duration time of the low penetration state exceeds the preset low penetration time; when Vd is not less than the low penetration setting value, judging whether Vd is greater than the exit low penetration setting value;
(4) when Vd is not greater than the exit low penetration setting value, entering low penetration, sending corresponding reactive current according to the voltage drop depth of the power grid, timing the entering time of the low penetration state, judging whether the duration time of the low penetration state exceeds the preset low penetration time, and jumping to the step (6) when the entering low penetration time exceeds; when Vd is larger than the exit low-penetration setting value, judging whether the high-voltage cascaded SVG is in a low-penetration state;
(5) when the high-voltage cascaded SVG is in a low-penetration state, blocking a set cycle driving pulse, returning to the step (1) to continue to sample the voltage of the power grid after the driving is recovered, and executing the steps (1) - (4) again; when the high-voltage cascaded SVG is not in a low-penetration state, directly switching to the step (1) to sample the voltage of the power grid, and similarly executing the steps (1) - (4) again;
(6) and (4) when the low penetration time exceeds in the step (4), the high-voltage cascaded SVG is disconnected, otherwise, the step (1) is carried out to continue to sample the voltage of the power grid, and the steps (1) - (4) are carried out again.
The method for acquiring and detecting the power grid voltage in the step (1) specifically comprises the following steps: and an AD (analog-to-digital) conversion module is adopted to collect the three-phase power grid voltage into the controller and carry out data operation on the three-phase power grid voltage.
The data operation specifically comprises the following steps: clark, Park coordinate transformation and phase-locked loop calculation.
When the low-voltage penetration is performed in the steps (3) and (4), outputting corresponding reactive current to support the power grid according to the standard, and specifically comprising the following steps of: the method comprises the steps of storing a current reactive power set value before entering low penetration, determining the reactive current required to be output by the high-voltage cascaded SVG according to the ratio of the grid voltage active component Vd obtained by phase locking to the rated grid voltage when entering low penetration, and recovering the set reactive current when entering low penetration when exiting low penetration;
after the ratio of the active component Vd of the power grid voltage obtained by phase locking to the rated power grid voltage meets the condition of low-pass recovery, overcurrent caused by unstable voltage is avoided, a proper cycle pulse is blocked first and then the low-pass state is exited, particularly in zero-pass recovery, generally about two power grid cycles.
Wherein, the power grid voltage dropping form in steps (3) and (4) is asymmetric dropping, realizes the bus voltage balance control under asymmetric dropping, specifically includes: under the condition of asymmetric drop, the voltage of each phase of bus of the high-voltage cascaded SVG is unbalanced, and the overvoltage of the bus is controlled and restrained by adopting negative sequence current;
and under the condition of restraining asymmetric dropping, a phase-locked loop cannot work when a 2-order harmonic ripple component and zero penetration in an active reactive component of the power grid voltage occur, and a reference phase is provided for reactive current.
Referring to fig. 2, a main circuit topology diagram of a control method for reducing high-voltage cascaded SVG low-voltage ride through off-line according to the present invention specifically includes: each phase is formed by cascading modularized H-bridge inverters, a voltage-sharing resistor is connected in parallel at the direct current side, and the three-phase inverters form a star-shaped structure and are connected with a power grid through a reactor.
Referring to fig. 3, a three-layer hierarchical control block diagram of the high-voltage cascaded SVG in the control method for reducing the low-voltage ride through and off-line of the high-voltage cascaded SVG of the present invention specifically includes: the device comprises a current inner ring, a voltage outer ring, a power outer ring and an in-phase equalizing ring, wherein the current inner ring control is dq control based on a two-phase rotating coordinate system, a positive sequence dq axis is used for stabilizing the voltage Vdc of a total bus and reactive current, and a negative sequence dq axis current is used for stabilizing the voltage balance of an interphase bus; the voltage outer ring is used for stabilizing the voltage of the total bus; the power outer loop calculates the reference value of the positive sequence current inner loop according to different operation modes, such as a constant power factor mode, a constant voltage mode, a constant reactive power mode, a constant current mode and the like in actual working conditions; realizing tracking V of in-phase grading ringdcm(m ═ a, b, c), (n ═ 1, 2, 3.. n) tracking Vdcm(m＝a，b，c)。
Referring to fig. 4, in the hierarchical bus voltage control block diagram of the control method for reducing the high-voltage cascaded SVG low-voltage ride-through and off-grid according to the present invention, the three phases a, b, and c are respectively formed by cascading N stages of modules, and the bus voltage of each stage is denoted as vdcm(m ═ a, b, c), (n ═ 1, 2, 3.. n), and V was obtained by filtering the second harmonic component through a 100Hz Notch Filterdcm(m ═ a, b, c), (n ═ 1, 2, 3.. n), and then the bus average voltage V of each phase is obtained by adding and averaging the bus voltages of the cascaded modules of each phasedcm(m ═ a, b, c), finally Vdcm(m ═ a, b, c) are added and averaged to obtain the total bus voltage average value Vdc. The goal of the voltage outer loop control algorithm is to implement the functions as shown by the arrows in fig. 4, namely the first layer: control VdcTracking Vdc_refCalled the total bus voltage control loop, second layer: control Vdcm(m ═ a, b, c) track VdcReferred to as interphase grading ring, third layer: control Vdcm(m ═ a, b, c), (n ═ 1, 2, 3.. n) tracking Vdcm(m ═ a, b, c), referred to as intra-phase grading rings.
Referring to fig. 5, a block diagram of a phase-locked loop of a control method for reducing the voltage ride-through and off-grid of the high-voltage cascaded SVG of the present invention, where the phase-locked loop performs phase tracking on the voltage of the power grid, specifically includes: the method is used for decomposing active current components and reactive current components of voltage and current, comparing the decomposed active voltage components with a low-penetration judgment value, using the value as a basis for entering or exiting low-penetration of the high-voltage cascaded SVG, and performing sliding filtering processing on the grid voltage angular frequency W obtained by phase locking to obtain WMaf. If the phase-locked angle of the phase-locked loop is different from the actual grid voltage by more than 90 degrees, U is judgedd<0, if the control loop gain of the phase-locked loop is changed, U needs to be judgeddSwitching the gain of the forward channel ensures that the gain is always greater than 0.
In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims (5)

1. A control method for reducing high-voltage cascade SVG low-voltage ride through off-line is characterized in that: the method specifically comprises the following steps:
(1) sampling the voltage of the power grid, tracking the phase of the voltage of the power grid by a phase-locked loop, and decomposing the voltage to obtain an active component V of the voltagedDecomposing the current to obtain a current active component and a current reactive component;
(2) judging the voltage active component V obtained by the phase-locked loopdWhether the voltage value is larger than the set voltage value of the sliding filter of the enabling calculation angular frequency, if the voltage value is VdWhen the current value is larger than the set voltage value of the sliding filtering of the enabling calculation angular frequency, the sliding filtering processing is carried out on the grid voltage angular frequency W obtained by phase locking to obtain the sliding average filtering angular frequency WMafUnder the condition of restraining asymmetric drop, a phase-locked loop cannot work when the phase-locked loop is in zero penetration and 2-order harmonic pulsation components in active and reactive components of the voltage of a power grid, and a reference phase is provided for reactive current;
(3) when said V isdWhen the voltage drop depth is smaller than the low penetration setting value, entering low penetration, sending corresponding reactive current according to the voltage drop depth of the power grid, timing the low penetration state entering time, and judging whether the low penetration state duration time exceeds the low penetration preset time or not; when said V isdWhen the value is not less than the low penetration setting value, the V is judgeddWhether the value is greater than the exit low penetration setting value;
(4) when said V isdWhen the voltage is not greater than the exit low-penetration setting value, entering low penetration, sending corresponding reactive current according to the voltage drop depth of the power grid, timing the low-penetration state entry time, judging whether the low-penetration state duration time exceeds the low-penetration preset time, and jumping to the step (6) when the low-penetration state entry time exceeds; when said V isdWhen the value is larger than the exit low-penetration setting value, judging whether the high-voltage cascaded SVG is in a low-penetration state;
(5) when the high-voltage cascaded SVG is in a low-penetration state, blocking a set cycle driving pulse, after the driving is recovered, switching to the step (1) to continue to sample the voltage of the power grid, and executing the steps (1) - (4) again; when the high-voltage cascaded SVG is not in a low-voltage state, directly switching to the step (1) to sample the voltage of the power grid, and similarly executing the steps (1) - (4) again;
(6) and (3) when the low penetration time exceeds in the step (4), the high-voltage cascaded SVG is disconnected, otherwise, the step (1) is carried out to continue to sample the voltage of the power grid, and the steps (1) - (4) are carried out again.
2. The control method for reducing the grid-off phenomenon of the low voltage ride through of the high-voltage cascaded SVG according to claim 1, wherein said method for collecting and detecting the grid voltage in step (1) specifically comprises: and an AD (analog-to-digital) conversion module is adopted to collect the three-phase power grid voltage into the controller and carry out data operation on the three-phase power grid voltage.
3. The control method for reducing the high-voltage cascaded SVG low voltage ride-through and off-grid as claimed in claim 2, wherein said data operation specifically comprises: clark, Park coordinate transformation and phase-locked loop calculation.
4. The control method for reducing the grid disconnection of the high-voltage cascaded SVG low voltage ride through according to claim 1, wherein said steps (3) and (4) are performed when the low ride through is entered, and then the corresponding reactive current is outputted according to the standard to support the grid, specifically comprising: storing the current reactive set value before entering low penetration, and obtaining the active component V of the network voltage according to the phase lock when entering low penetrationdAnd the ratio of the output current to the rated power grid voltage determines the magnitude of the reactive current required to be output by the high-voltage cascaded SVG, and the magnitude of the reactive current set when the high-voltage cascaded SVG enters low-voltage penetration needs to be restored when the high-voltage cascaded SVG exits low-voltage penetration.
5. The control method for reducing the grid-off phenomenon of the cascaded SVG with high voltage and low voltage ride through according to claim 1, wherein the grid voltage drop in steps (3) and (4) is an asymmetric drop, and the bus voltage balance control is realized under the asymmetric drop, specifically comprising: under the condition of asymmetric drop, the voltage of each phase of the high-voltage cascaded SVG bus can be unbalanced, and the bus overvoltage is restrained by adopting negative sequence current control.
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CN109560571A (en) * 2018-11-06 2019-04-02 深圳市禾望电气股份有限公司 Low voltage ride through control method, static reactive generator and storage medium
CN111769588A (en) * 2019-04-02 2020-10-13 中国电力科学研究院有限公司 VSG low-voltage ride-through control method and system based on power grid unbalance fault
CN112531774A (en) * 2020-12-01 2021-03-19 辽宁东科电力有限公司 Low-voltage ride-through operation control method of inverter type distributed power supply

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107732956A (en) * 2017-07-10 2018-02-23 华北电力大学（保定） The two-stage type photovoltaic parallel in system low-voltage ride-through method of Variable power pursuit path
CN109560571A (en) * 2018-11-06 2019-04-02 深圳市禾望电气股份有限公司 Low voltage ride through control method, static reactive generator and storage medium
CN111769588A (en) * 2019-04-02 2020-10-13 中国电力科学研究院有限公司 VSG low-voltage ride-through control method and system based on power grid unbalance fault
CN112531774A (en) * 2020-12-01 2021-03-19 辽宁东科电力有限公司 Low-voltage ride-through operation control method of inverter type distributed power supply

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