CN110649647A - Photovoltaic inverter low-voltage ride-through control based on reactive current boundary conditions under distribution network symmetric faults - Google Patents

Photovoltaic inverter low-voltage ride-through control based on reactive current boundary conditions under distribution network symmetric faults Download PDF

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CN110649647A
CN110649647A CN201910785507.5A CN201910785507A CN110649647A CN 110649647 A CN110649647 A CN 110649647A CN 201910785507 A CN201910785507 A CN 201910785507A CN 110649647 A CN110649647 A CN 110649647A
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distribution network
photovoltaic inverter
reactive current
voltage ride
photovoltaic
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CN110649647B (en
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黄华颖
黄辉
王庆斌
叶烜荣
叶锦坤
刘雄光
戴一宇
曹华珍
吴亚雄
唐俊熙
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Guangdong Power Grid Co Ltd
Yunfu Power Supply Bureau of Guangdong Power Grid Co Ltd
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Guangdong Power Grid Co Ltd
Yunfu Power Supply Bureau of Guangdong Power Grid Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—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
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/50—Controlling the sharing of the out-of-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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation

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Abstract

The invention discloses photovoltaic inverter low-voltage ride-through control based on reactive current boundary conditions under distribution network symmetric faults. Inputting distribution network bus rated voltage, short-circuit impedance and cable impedance related parameters from a photovoltaic access point to a distribution network bus, which are required by calculating reactive current boundary conditions under the symmetrical fault of a distribution network, according to the actual installation condition of a photovoltaic inverter; calculating reactive current boundary conditions under the symmetrical fault of the distribution network; correcting the low voltage ride through maximum reactive current effective value of the photovoltaic inverter according to the obtained reactive current boundary condition; and calculating a low-voltage ride through current command of the photovoltaic inverter. The method can effectively avoid the problems of unstable work and irregular output current phase of the photovoltaic inverter caused by the fact that the magnitude of the reactive current output by the photovoltaic inverter exceeds the boundary condition under certain working conditions (for example, the distribution network has a symmetrical short-circuit fault and the fault point is positioned on a distribution network bus) when the distribution network has a short-circuit fault.

Description

Photovoltaic inverter low-voltage ride-through control based on reactive current boundary conditions under distribution network symmetric faults
Technical Field
The invention relates to the technical field of power electronic converters, in particular to photovoltaic inverter low-voltage ride-through control based on reactive current boundary conditions under the symmetrical faults of a distribution network.
Background
The photovoltaic inverter is a power electronic converter which converts direct current output by a photovoltaic module into alternating current and is key equipment of a photovoltaic power generation system. Compared with a centralized photovoltaic power station, the distributed photovoltaic system has the advantages of flexible site selection, convenience in consumption and low investment, is one of main ways of new energy power generation encouraged by the state in recent years, and is mainly applied to medium-voltage power distribution network occasions. When the parallel voltage is normal, a photovoltaic inverter in the distributed photovoltaic system outputs the maximum power by adopting a Maximum Power Point Tracking (MPPT) algorithm, and when the grid-connected voltage is under-voltage, the maximum power is required to meet the related low-voltage ride-through regulation in the photovoltaic grid-connected inverter technical specification (NB/T32004-2018) of the national standard, namely: when the voltage of the grid-connected point is lower than 0.9 times of the rated voltage, a low voltage ride through curve and dynamic reactive power capacity shown in the formula (2) need to be satisfied:
Figure BDA0002177896680000011
in the formula ITThe inductive reactive current is positive and the capacitive reactive current is negative for the reactive current output by the inverter; k is a proportional value of the output reactive current and the voltage change of the inverter, and the value range is 1.5-2.5; u shapeTThe voltage is a per unit value of the photovoltaic grid-connected point voltage; i isNThe rated output current of the inverter is an effective value.
When a distribution network has a short-circuit fault, the grid-connected point voltage can be effectively supported due to the fact that the photovoltaic inverter outputs inductive reactive current, in practical application, larger inductive reactive current is often selected to be output, but under certain working conditions (for example, the distribution network has a symmetrical short-circuit fault and the fault point is located on a distribution network bus), the photovoltaic inverter is unstable in work and irregular in output current phase.
At present, the related research on the low voltage ride through of the photovoltaic inverter mainly focuses on the phase locking method of the photovoltaic inverter under the short-circuit fault and the related standard research on the output dynamic reactive current, the phenomena of unstable work and irregular output current phase of the photovoltaic inverter under certain working conditions (such as symmetrical short-circuit fault of the distribution network and the fault point located on a distribution network bus) when the distribution network has the short-circuit fault are not considered, and the research on the reactive current boundary condition and the low voltage ride through control of the photovoltaic inverter related to the low voltage ride through is not carried out.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides the photovoltaic inverter low-voltage ride-through control based on the reactive current boundary condition under the symmetrical fault of the distribution network.
In order to solve the technical problems, the invention adopts the technical scheme that: a photovoltaic inverter low voltage ride through control based on reactive current boundary conditions under distribution network symmetric faults comprises the following steps:
s1: inputting parameters related to reactive current boundary condition calculation under the condition of actual installation of the photovoltaic inverter and the symmetric fault of the distribution network;
s2: calculating reactive current boundary conditions under the symmetrical fault of the distribution network;
s3: correcting the low voltage ride through maximum reactive current effective value of the photovoltaic inverter according to the boundary condition;
s4: and calculating a low-voltage ride through current command of the photovoltaic inverter.
Preferably, in step S1, relevant parameters are collected from the trunk line diagram and the distribution network condition, and the input relevant parameters include the distribution network rated phase voltage UNAnd a system short circuit resistor RSSystem short circuit reactance XSCable resistance R from photovoltaic access point to distribution network bus1And an inter-triphase short-circuit resistance R.
Preferably, the reactive current boundary condition under the symmetric fault of the distribution network is calculated by using the following formula:
Figure BDA0002177896680000021
wherein IPVAnd outputting an inductive reactive current effective value for the photovoltaic inverter.
Preferably, in the step S3, when the boundary condition is 0 ≦ IPV≤IqbcIn which IqbcIs the reactive current boundary upper limit value output by the photovoltaic inverter,
Figure BDA0002177896680000022
the step S3 specifically includes the following steps;
s 31: comparison IqbcWhether the rated current I of the photovoltaic inverter is less than 1.05 timesN: if yes, go to step s32, otherwise go to step s 33;
s 32: photovoltaic inverter low voltage ride through maximum reactive current effective value Max during distribution network symmetrical faultsy＝0.9Iqbc；
s 33: photovoltaic inverter low voltage ride through maximum reactive current effective value Max during distribution network symmetrical faultsy＝1.05IN。
Preferably, the step S4 specifically includes the following steps:
s 41: reading original active current instruction IrefObtaining the maximum failure of the photovoltaic inverter under the symmetrical fault according to the step S3Effective value of work current Maxsy；
s 42: detecting photovoltaic grid-connected point voltageExtracting thePositive and negative sequence components U ofp、Un；
s 43: judge UpWhether or not less than 0.9UNIf yes, go to step s45, otherwise go to step s 44;
s 44: reactive current instruction I of photovoltaic inverter q0, photovoltaic inverter active current command Id＝Iref；
s 45: judge UnWhether or not it is greater than 0.1UNIf yes, go to step s46, otherwise go to step s 47;
s 46: maximum Max of output current of photovoltaic inverter is 0.4INThen, go to step s 48;
s 47: maximum value Max of output current of photovoltaic inverter is MaxsyProceeding to step s 48;
s 48: calculating reactive current instruction I of photovoltaic inverterq＝-2*(0.9-Up/UN)*IN；
s 49: judgment of IqIf the value is greater than Max, entering a step s410 if the value is greater than Max, or entering a step s411 if the value is not greater than Max;
s410：Iq＝-Max，Id＝0；
s411：Iq＝-2*(0.9-Up/UN)*IN，Id＝(Max2-Iq 2)0.5。
compared with the prior art, the beneficial effects are:
the invention introduces the reactive current boundary condition under the distribution network symmetrical fault which is consistent with the actual access condition of the photovoltaic inverter, is used for correcting the maximum reactive current effective value of the low voltage ride through of the photovoltaic inverter, and can effectively avoid the phenomena of unstable work and irregular output current phase of the photovoltaic inverter caused by the fact that the magnitude of the reactive current output by the photovoltaic inverter exceeds the boundary condition under certain working conditions (for example, the distribution network has the symmetrical short circuit fault and the fault point is positioned on a distribution network bus) when the distribution network has the short circuit fault.
Drawings
FIG. 1 is a diagram of an equivalent circuit of a distribution network when a bus of the distribution network has a symmetric short-circuit fault;
FIG. 2 is a schematic diagram of photovoltaic inverter low voltage ride through control based on reactive current boundary conditions under a symmetrical fault of a distribution network;
FIG. 3 is a schematic flow chart illustrating a process of correcting the low voltage ride through maximum reactive current effective value of the photovoltaic inverter according to the boundary condition;
FIG. 4 is a schematic view of a calculation flow of a low voltage ride through command of the photovoltaic inverter;
fig. 5 is a comparison of simulation waveforms of the low voltage ride through control effect of the photovoltaic inverter.
Detailed Description
The drawings are for illustrative purposes only and are not to be construed as limiting the patent; for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present patent.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "long", "short", etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the drawings, it is only for convenience of description and simplicity of description, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationships in the drawings are only used for illustrative purposes and are not to be construed as limitations of the present patent, and specific meanings of the terms may be understood by those skilled in the art according to specific situations.
The technical scheme of the invention is further described in detail by the following specific embodiments in combination with the attached drawings:
examples
Fig. 1 is a diagram of an equivalent circuit of a distribution network when a symmetric short-circuit fault occurs in a distribution network bus, where the diagram includes: a system power supply, a system impedance, a photovoltaic power supply, a cable impedance, and a short circuit resistor. The system power supply is connected with one port of the system impedance in series, and the other port of the system impedance is connected to a short-circuit fault point; the photovoltaic power supply is connected with the cable impedance in series, and the other port of the cable impedance is connected to a short-circuit fault point; the short-circuit resistor is connected between the short-circuit fault point and a reference ground.
Fig. 1 shows the actual access situation of the photovoltaic inverter, including relevant parameters required by reactive current boundary conditions under the symmetric fault of the distribution network.
Fig. 2 is a schematic diagram of an exemplary photovoltaic inverter low voltage ride through control based on reactive current boundary conditions under a symmetrical fault of a distribution network, which includes four steps:
s1: inputting parameters related to reactive current boundary condition calculation under the condition of actual installation of the photovoltaic inverter and the symmetric fault of the distribution network;
s2: calculating reactive current boundary conditions under the symmetrical fault of the distribution network;
s3: correcting the low voltage ride through maximum reactive current effective value of the photovoltaic inverter according to the boundary condition;
s4: and calculating a low-voltage ride through current command of the photovoltaic inverter.
In step S1, the required parameters can be collected from the trunk map and distribution network conditions, and in this embodiment, can be collected from fig. 1: the input relevant parameters include: distribution network rated phase voltage UNAnd a system short circuit resistor RSSystem short circuit reactance XSCable resistance R from photovoltaic access point to distribution network bus1And an inter-triphase short-circuit resistance R.
In step S2, the reactive current boundary condition under the symmetric fault of the distribution network may be calculated by using formula (1);
Figure BDA0002177896680000051
in the formula IPVAnd outputting an inductive reactive current effective value for the photovoltaic inverter.
Based on fig. 1, the reactive current boundary condition obtaining process under the distribution network symmetric fault is as follows:
based on kirchhoff's law, the output current of the photovoltaic inverter can be obtained by the effective circuit shown in figure 1
Figure BDA0002177896680000052
And system power supply voltage
Figure BDA0002177896680000053
The relation between:
Figure BDA0002177896680000054
because the short-circuit fault point is located in the distribution network bus, the voltage of the photovoltaic grid-connected point is very low, active current is not output, only inductive reactive current is output, and the following can be obtained:
Figure BDA0002177896680000055
wherein j is a unit imaginary number;
Figure BDA0002177896680000056
rated output current for the inverter; i isPVIs composed of
Figure BDA0002177896680000057
The mold of (4);is the photovoltaic output voltage; u shapePVIs composed of
Figure BDA0002177896680000059
The die of (1).
The formula (5) can be substituted for the formula (4):
Figure BDA00021778966800000510
setting:the initial phase is zero, and the phase voltage amplitude is rated voltage UNAnd Z isS＝RS+jXS、Z1＝R1+jX1(RS、XSRespectively is ZSResistance and reactance of (d); r1、X1Respectively is Z1Resistance and reactance of (d); ) Then, there are:
Figure BDA00021778966800000512
in the formula (7)Is a unit phasor.
In the formula (7)
Figure BDA00021778966800000514
Is a vector of the unit,
Figure BDA00021778966800000515
should be equal to 1, obtained from (7):
||UN·R/(Rs+R+j·Xs)||＝||IPV·(-(R1+R)+j·(UPV/IPV-X1))|| (8)
namely:
Figure BDA0002177896680000061
due to UPVThe effective value of the output voltage of the photovoltaic inverter is large in actual variation range and can be (0-1.3U)N) Therefore, U contained in formula (6)PVThe term value change range of (2) is large, and the term value change range can be considered as a part of the automatic adjustment of the inverter and is not taken as a constraint condition. From the formula (6)：
Figure BDA0002177896680000062
Namely: when the symmetric short-circuit fault occurs in the distribution network and the fault point is positioned on the distribution network bus, the photovoltaic inverter can send out an inductive reactive current effective value IPVThe requirements are as follows:
Figure BDA0002177896680000063
such as IPVIf the formula (11) is not satisfied, the inductive reactive current emitted by the photovoltaic inverter cannot reach a stable state, and the phenomena of unstable work and irregular output current phase of the inverter occur.
In step S3, when the boundary condition is 0 ≦ IPV≤IqbcIn which IqbcIs the reactive current boundary upper limit value output by the photovoltaic inverter,an exemplary flowchart for modifying the pv inverter low-voltage ride-through maximum reactive current effective value according to the boundary conditions is shown in fig. 3, and includes 3 steps:
s 31: comparison IqbcWhether the rated current I of the photovoltaic inverter is less than 1.05 timesN: if yes, go to step s32, otherwise go to step s 33;
s 32: considering 10% of margin, the photovoltaic inverter passes through the maximum reactive current effective value Max under the condition of low voltage during the symmetrical fault of the distribution networksy＝0.9Iqbc；
s 33: photovoltaic inverter low voltage ride through maximum reactive current effective value Max during distribution network symmetrical faultsy＝1.05IN。
In step S4, an exemplary calculation flow diagram of the pv inverter low-voltage through current command is shown in fig. 4, and includes 11 steps:
s 41: reading original active current instruction IrefObtaining the maximum reactive current of the photovoltaic inverter under the symmetrical fault according to the step S3Max effective valuesy；
s 42: detecting photovoltaic grid-connected point voltageExtracting the
Figure BDA0002177896680000066
Positive and negative sequence components U ofp、Un；
s 43: judge UpWhether or not less than 0.9UNIf yes, go to step s45, otherwise go to step s 44;
s 44: reactive current instruction I of photovoltaic inverter q0, photovoltaic inverter active current command Id＝Iref；
s 45: judge UnWhether or not it is greater than 0.1UNIf yes, go to step s46, otherwise go to step s 47;
s 46: maximum Max of output current of photovoltaic inverter is 0.4INThen, go to step s 48;
s 47: maximum value Max of output current of photovoltaic inverter is MaxsyProceeding to step s 48;
s 48: calculating reactive current instruction I of photovoltaic inverterq＝-2*(0.9-Up/UN)*IN；
s 49: judgment of IqIf the value is greater than Max, entering a step s410 if the value is greater than Max, or entering a step s411 if the value is not greater than Max;
s410：Iq＝-Max，Id＝0；
s411：Iq＝-2*(0.9-Up/UN)*IN，Id＝(Max2-Iq 2)0.5。
the system structure and test mode are as follows:
the method adopts an equivalent circuit with the structure as shown in FIG. 1 to carry out the symmetrical short-circuit fault simulation of the distribution network bus, wherein the simulation parameters are as follows: rated phase voltage U of system power supplyN10/1.732-5.77 kV, short-circuit resistance RS0.019 Ω, short-circuit reactance XS0.19 Ω, cable resistance R10.12 omega, three-phase short-circuit resistance RSRated current I of photovoltaic inverter is 0.001 omegaN288.7A; the photovoltaic power supply adopts the traditional voltage ride through control and the photovoltaic inverter low-voltage ride through control based on the reactive current boundary condition under the symmetrical fault of the distribution network, which is provided by the invention.
The invention provides a photovoltaic inverter low-voltage ride through control based on reactive current boundary conditions under the symmetrical faults of a distribution network, which comprises the following steps:
according to the step S1, parameters related to the actual installation of the photovoltaic inverter and the calculation of the reactive current boundary condition under the symmetric fault of the distribution network, which are obtained by the simulation parameters, are input: u shapeN＝5.77kV，RS＝0.019Ω，XS＝0.19Ω，R1＝0.12Ω，RS＝0.001Ω；
According to the step S2, calculating the boundary condition I of the inductive reactive current output by the photovoltaic inverter under the symmetrical short-circuit fault of the distribution network by adopting the formula (1)PV≤IqbcBy calculation, Iqbc＝250.43A；
According to step S3, the effective value of the maximum reactive current of the low voltage ride through of the photovoltaic inverter is corrected, due to Iqbc<1.05IN303.1A, the photovoltaic inverter passes through the maximum reactive current effective value Max at the low voltage when the distribution network is in the symmetrical faultsy＝IqbcConsider a 10% margin at 250.43A, Maxsy＝0.9Iqbc＝225A；
Calculating a low-voltage ride through current instruction of the photovoltaic inverter according to the step S4, wherein when a symmetric short-circuit fault of a distribution network bus occurs, a positive sequence component U of the photovoltaic grid-connected point voltagep＝36V<0.9UN5.193kV with negative sequence component Un＝0V<0.1UN0.577kV, Max 225A; calculating reactive current instruction I of photovoltaic inverterq＝-2*(0.9-Up/UN)*IN-519.66 a; due to IqThe absolute value is larger than Max, and finally the reactive current instruction I of the photovoltaic inverterqMax-225A, active current command Id＝0。
Fig. 5 is a comparison of simulated waveforms of the low voltage ride through control effect of the photovoltaic inverter according to an example of the present invention.
The 10kV distribution network bus symmetric short-circuit fault occurs in 0.5 s-1 s, as can be seen from FIG. 5, the photovoltaic inverter low-voltage ride-through control (the low-voltage ride-through control provided by the invention) based on the reactive current boundary condition under the distribution network symmetric fault is adopted, and the photovoltaic inverter outputs stable three-phase current after a positive transient process when the symmetric fault occurs; by adopting the traditional low-voltage ride through control, the three-phase circuit output by the photovoltaic inverter after the transient process is ended is unstable when a symmetrical fault occurs, and the phase of the output current is irregular.
The invention relates to a photovoltaic inverter low-voltage ride-through control based on reactive current boundary conditions under the symmetrical faults of a distribution network. According to the actual installation condition of the photovoltaic inverter, inputting distribution network bus rated voltage, short-circuit impedance and cable impedance related parameters from a photovoltaic access point to a distribution network bus, which are required by calculating reactive current boundary conditions under the symmetrical faults of a distribution network, calculating the reactive current boundary conditions under the symmetrical faults of the distribution network, correcting the maximum reactive current effective value of low-voltage ride-through of the photovoltaic inverter, and calculating a low-voltage ride-through current instruction of the photovoltaic inverter. The photovoltaic inverter low-voltage ride-through control based on the reactive current boundary condition under the distribution network symmetrical fault can effectively avoid the phenomena of unstable work and irregular output current phase of the photovoltaic inverter due to the fact that the magnitude of the reactive current output by the photovoltaic inverter exceeds the boundary condition under certain working conditions (for example, the distribution network has the symmetrical short-circuit fault and the fault point is positioned on a distribution network bus) when the distribution network has the short-circuit fault.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (5)

1. Photovoltaic inverter low-voltage ride through control based on reactive current boundary conditions under distribution network symmetric faults is characterized by comprising the following steps:
s1: inputting parameters related to reactive current boundary condition calculation under the condition of actual installation of the photovoltaic inverter and the symmetric fault of the distribution network;
s2: calculating reactive current boundary conditions under the symmetrical fault of the distribution network;
s3: correcting the low voltage ride through maximum reactive current effective value of the photovoltaic inverter according to the boundary condition;
s4: and calculating a low-voltage ride through current command of the photovoltaic inverter.
2. The photovoltaic inverter low-voltage ride-through control based on reactive current boundary conditions under distribution network symmetric faults as claimed in claim 1, wherein in the step S1, relevant parameters are collected from a trunk line diagram and distribution network conditions, and the input relevant parameters comprise a distribution network rated phase voltage UNAnd a system short circuit resistor RSSystem short circuit reactance XSCable resistance R from photovoltaic access point to distribution network bus1And an inter-triphase short-circuit resistance R.
3. The photovoltaic inverter low voltage ride-through control based on the reactive current boundary condition under the symmetrical fault of the distribution network according to claim 2, characterized in that the reactive current boundary condition under the symmetrical fault of the distribution network is calculated by using the following formula:
Figure FDA0002177896670000011
wherein IPVAnd outputting an inductive reactive current effective value for the photovoltaic inverter.
4. The photovoltaic inverter low-voltage ride-through control based on reactive current boundary condition under distribution network symmetric fault as claimed in claim 3, wherein in step S3, when the boundary condition is 0 ≦ IPV≤IqbcIn which IqbcIs the reactive current boundary upper limit value output by the photovoltaic inverter,the step S3 specifically includes the following steps:
s 31: comparison IqbcWhether the rated current I of the photovoltaic inverter is less than 1.05 timesN: if yes, go to step s32, otherwise go to step s 33;
s 32: photovoltaic inverter low voltage ride through maximum reactive current effective value Max during distribution network symmetrical faultsy＝0.9Iqbc；
s 33: photovoltaic inverter low voltage ride through maximum reactive current effective value Max during distribution network symmetrical faultsy＝1.05IN。
5. The photovoltaic inverter low-voltage ride-through control based on the reactive current boundary condition under the distribution network symmetric fault according to claim 4, wherein the step S4 specifically includes the following steps:
s 41: reading original active current instruction IrefObtaining the maximum reactive current effective value Max of the photovoltaic inverter under the symmetrical fault according to the step S3sy；
s 42: detecting photovoltaic grid-connected point voltage
Figure FDA0002177896670000021
Extracting the
Figure FDA0002177896670000022
Positive and negative sequence components U ofp、Un；
s 43: judge UpWhether or not less than 0.9UNIf yes, go to step s45, otherwise go to step s 44;
s 44: reactive current instruction I of photovoltaic inverterq0, photovoltaic inverter active current command Id＝Iref；
s 45: judge UnWhether or not it is greater than 0.1UNIf yes, go to step s46, otherwise go to step s 47;
s 46: output current of photovoltaic inverterMax 0.4INThen, go to step s 48;
s 47: maximum value Max of output current of photovoltaic inverter is MaxsyProceeding to step s 48;
s 48: calculating reactive current instruction I of photovoltaic inverterq＝-2*(0.9-Up/UN)*IN；
s 49: judgment of IqIf the value is greater than Max, entering a step s410 if the value is greater than Max, or entering a step s411 if the value is not greater than Max;
s410：Iq＝-Max，Id＝0；
s411：Iq＝-2*(0.9-Up/UN)*IN，Id＝(Max2-Iq 2)0.5。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115663881A (en) * 2022-09-07 2023-01-31 国网重庆市电力公司电力科学研究院 Current control method of power system under symmetrical short-circuit fault of alternating-current power grid

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102761135A (en) * 2012-07-19 2012-10-31 河海大学 Low voltage ride through method for single-stage photovoltaic grid-connected inverter
CN104734191A (en) * 2015-03-31 2015-06-24 华南理工大学 Photovoltaic grid-connected inverter low-voltage ride through method based on reactive current injection
CN105591401A (en) * 2016-01-27 2016-05-18 浙江大学 Photovoltaic low-voltage crossing method containing reactive power current injection
CN105743128A (en) * 2016-05-05 2016-07-06 上海电机学院 Low voltage ride through control method of grid-connected photovoltaic power generation system
KR20160094810A (en) * 2015-02-02 2016-08-10 두산중공업 주식회사 Wind turbine and Method for LVRT control of wind turbine
CN107706893A (en) * 2017-10-31 2018-02-16 广东电网有限责任公司惠州供电局 A kind of computational methods of DG accesses distribution optimum capacity
CN107766596A (en) * 2016-08-18 2018-03-06 中国电力科学研究院 A kind of low voltage ride-through capability method of tire based on typical fault operating mode collection
CN109728597A (en) * 2017-10-30 2019-05-07 中国电力科学研究院有限公司 A kind of low voltage ride through of photovoltaic inverter property fitting method and system
US20190252884A1 (en) * 2018-02-15 2019-08-15 General Electric Company Reactive Current Margin Regulator for Power Systems

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102761135A (en) * 2012-07-19 2012-10-31 河海大学 Low voltage ride through method for single-stage photovoltaic grid-connected inverter
KR20160094810A (en) * 2015-02-02 2016-08-10 두산중공업 주식회사 Wind turbine and Method for LVRT control of wind turbine
CN104734191A (en) * 2015-03-31 2015-06-24 华南理工大学 Photovoltaic grid-connected inverter low-voltage ride through method based on reactive current injection
CN105591401A (en) * 2016-01-27 2016-05-18 浙江大学 Photovoltaic low-voltage crossing method containing reactive power current injection
CN105743128A (en) * 2016-05-05 2016-07-06 上海电机学院 Low voltage ride through control method of grid-connected photovoltaic power generation system
CN107766596A (en) * 2016-08-18 2018-03-06 中国电力科学研究院 A kind of low voltage ride-through capability method of tire based on typical fault operating mode collection
CN109728597A (en) * 2017-10-30 2019-05-07 中国电力科学研究院有限公司 A kind of low voltage ride through of photovoltaic inverter property fitting method and system
CN107706893A (en) * 2017-10-31 2018-02-16 广东电网有限责任公司惠州供电局 A kind of computational methods of DG accesses distribution optimum capacity
US20190252884A1 (en) * 2018-02-15 2019-08-15 General Electric Company Reactive Current Margin Regulator for Power Systems

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
张润坤: "含分布式光伏电源的配电网继电保护研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》 *
韩贤岁等: "对称和不对称故障下的并网光伏逆变器低电压穿越研究", 《电测与仪表》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115663881A (en) * 2022-09-07 2023-01-31 国网重庆市电力公司电力科学研究院 Current control method of power system under symmetrical short-circuit fault of alternating-current power grid
CN115663881B (en) * 2022-09-07 2024-04-30 国网重庆市电力公司电力科学研究院 Current control method for power system under symmetrical short-circuit fault of alternating-current power grid

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