CN110571859B - Method for improving grid-connected operation capacity of double-fed wind turbine generator under power grid fault - Google Patents

Method for improving grid-connected operation capacity of double-fed wind turbine generator under power grid fault Download PDF

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CN110571859B
CN110571859B CN201910959097.1A CN201910959097A CN110571859B CN 110571859 B CN110571859 B CN 110571859B CN 201910959097 A CN201910959097 A CN 201910959097A CN 110571859 B CN110571859 B CN 110571859B
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wind turbine
turbine generator
fed wind
grid
doubly
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CN110571859A (en
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欧阳金鑫
郑迪
庞茗予
熊小伏
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Chongqing University
China Jiliang University
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China Jiliang University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—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
    • 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
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects

Abstract

The invention discloses a method for improving grid-connected operation capacity of a doubly-fed wind turbine generator under power grid fault, wherein when the power grid fault causes a generator terminal voltage UsmNot more than 0.9p.u. and rotor current IrmWhen the current is more than or equal to 2.0p.u., Crowbar is put into and the rotor side converter is locked; when the rotor current I is detectedrmQuitting Crowbar when the current is less than or equal to 1.9p.u., and setting the control instruction value of the rotor-side converter to be Psc、Qsc(ii) a Calculating the terminal voltage and the minimum grid-connection duration t after control is implementedd,min(ii) a At t < td,minInner UsmWhen the value is more than 0.9p.u., the instruction value is set to Psn、Qsn(ii) a Otherwise, always remain as Psc、QscAnd detecting whether the parameter is out of limit, if so, when t is more than td,minThen the double-fed wind turbine generator is withdrawn, if the double-fed wind turbine generator is not out of limit, when the U is not out of limitsmWhen the value is more than 0.9p.u., the instruction value is set to Psn、Qsn. The method can give full play to the flexible power control capability and the safety margin of the double-fed wind turbine generator, improve the continuous grid-connected operation capability of the double-fed wind turbine generator under the power grid fault, and provide effective technical measures for the operation control of a high-proportion wind power system.

Description

Method for improving grid-connected operation capacity of double-fed wind turbine generator under power grid fault
Technical Field
The invention relates to the field of protection and control of an electric power system, in particular to a method for improving grid-connected operation capacity of a double-fed wind turbine generator under a power grid fault.
Background
In order to solve the global energy crisis, wind power generation is rapidly developed in the global scope. The regional power grid rich in wind energy gradually forms a power grid pattern containing high-proportion wind power. The traditional wind turbine generator adopts a cage type induction generator or a winding type induction generator, and a generator stator winding is directly connected with a step-up transformer and is respectively called as a type I wind turbine generator and a type II wind turbine generator. The type II unit is provided with a variable resistor on a rotor winding, and constant power output under gust is realized through adjustment of the variable resistor. However, the output power cannot be changed along with the change of the wind speed because the rotating speed of the wind turbine generator is not changed, and the wind energy utilization rate is not high. On the basis of the II-type unit, the III-type unit adopts the power electronic converter to provide variable frequency excitation for the winding type induction generator, so that the current and the voltage of the rotor can be immediately regulated, the maximum power output under different wind speeds can be realized, the wind energy utilization efficiency is greatly improved, the loss is smaller, and the response performance is greatly improved. The III-type unit rotor can also exchange power with a power grid through a back-to-back converter and form a double channel with a stator winding, so that the III-type unit rotor is also called a double-fed wind turbine generator. After decades of development, doubly-fed wind turbines have dominated the wind power equipment market.
The double-fed wind turbine generator adopts a back-to-back converter to provide excitation, and the output power of the double-fed wind turbine generator can be flexibly controlled by adjusting the frequency, amplitude and phase of excitation voltage, so that the operation mode and the output characteristic of the double-fed wind turbine generator are determined by the control mode of the converter. Under the condition of a normal power grid, a doubly-fed wind turbine usually operates with a unit power factor, a rotor-side converter and a grid-side converter of the doubly-fed wind turbine usually adopt a vector control strategy based on a current closed loop, the rotor-side converter realizes the maximum output of power through the maximum wind energy tracking control, and the grid-side converter mainly adopts direct-current bus voltage control. With the development and maturity of a converter control technology, the doubly-fed wind turbine generator can keep converter control under slight faults of a power grid, and can restore the converter control after transient impact is avoided by utilizing fault ride-through control such as a rotor crowbar and the like under serious faults, so that the flexible power control capability under the faults is kept, the feasibility is provided for the doubly-fed wind turbine generator to participate in emergency control of the power grid through power regulation during continuous grid-connected operation, and the emergency control of the power grid based on the doubly-fed wind turbine generator becomes a research hotspot. The method has certain research achievements in the aspects of power grid power angle stable control, emergency power control and the like based on the double-fed wind turbine generator.
The continuous grid-connected operation capability of the double-fed wind turbine generator is the basis of the emergency control of the power grid based on the double-fed wind turbine generator. However, there is little research on how to improve the grid-connected operation capability of the doubly-fed wind turbine generator under the grid fault. The minimum grid-connected duration of a unit under a grid fault reflects the capability of the unit to keep grid-connected operation. The minimum grid-connected duration of the doubly-fed wind turbine generator is determined by the grid-connected point voltage under the grid fault, and can be calculated by the wind power grid-connected guide rule according to the grid-connected point voltage. However, in the existing methods, the minimum grid-connected duration of the doubly-fed wind turbine generator under the grid fault is determined by the wind power grid-connected point voltage at the moment of the fault, and the minimum grid-connected duration is used as a reference for the off-grid of the doubly-fed wind turbine generator. However, during the grid fault period, the doubly-fed wind turbine generator outputs reactive power to the grid by adjusting the reactive power control reference value, so that the voltage of the grid-connected point is increased, that is, the minimum grid-connected duration of the wind turbine generator is reduced by the existing method, and the grid-connected operation capability of the wind turbine generator is reduced.
In addition, the minimum grid-connected duration is closely related to the grid-connected point voltage, if the grid-connected point voltage is higher under the control of the double-fed wind turbine generator, the change of parameters such as rotor current, rotating speed and direct-current bus voltage of the double-fed wind turbine generator is smaller, the off-grid possibility of the double-fed wind turbine generator is smaller, and the minimum grid-connected duration is longer. Therefore, the grid-connected operation capability of the doubly-fed wind turbine generator under the grid fault is also related to the control capability of the doubly-fed wind turbine generator on the grid-connected point voltage. At present, the control capability of a double-fed wind turbine generator is described by taking the grid-connected point voltage at the moment of fault occurrence as a constraint condition in the existing method, and the grid-connected point voltage is controlled by coordinating with a grid-side converter, other units in a wind power plant and reactive compensation equipment on the basis of the constraint condition. However, as the output power of the doubly-fed wind turbine is adjusted, the power flow of the power grid will be changed, and the voltage of the grid-connected point of the doubly-fed wind turbine is changed, so that the power control capability of the doubly-fed wind turbine is changed. The existing method does not consider the coupling effect of the double-fed wind turbine generator and the power grid, and inevitably causes the power control capability of the double-fed wind turbine generator not to be fully exerted, thereby seriously influencing the grid-connected operation capability of the double-fed wind turbine generator under the power grid fault.
In summary, with the continuous increase of the installed capacity of wind power, the doubly-fed wind turbine generator is applied to the emergency control of the power grid so as to improve the transient response speed and the control capability of the power grid, which is a necessary trend of the development of the power system. However, the existing method does not fully consider the change of the control capacity of the doubly-fed wind turbine generator during the grid fault period and the influence of grid voltage control on the minimum duration, so that the grid-connected operation capacity of the doubly-fed wind turbine generator during the grid fault period is greatly limited, and the application of the doubly-fed wind turbine generator in the grid emergency control is hindered. Therefore, how to further dig the control capability of the doubly-fed wind turbine generator and improve the continuous grid-connection time of the doubly-fed wind turbine generator under the grid fault so as to improve the grid-connection operation capability of the doubly-fed wind turbine generator under the grid fault becomes a problem which needs to be solved by technical personnel in the field.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a method for improving the grid-connected operation capacity of a double-fed wind turbine generator under the grid fault, which fully considers the influence of the power adjustment of the double-fed wind turbine generator on the grid voltage during the grid fault, fully considers the influence of the grid voltage rise on the minimum grid-connected duration of the double-fed wind turbine generator during the grid fault, can determine the active and reactive control reference values of the double-fed wind turbine generator according to the severity of the grid fault, fully exerts the flexible power control capacity and the impact resistance capacity of the double-fed wind turbine generator, prolongs the continuous grid-connected duration of the double-fed wind turbine generator under the grid fault, improves the grid-connected operation capacity of the double-fed wind turbine generator, is not only beneficial to realizing the fault ride-through of the double-fed wind turbine.
In order to solve the technical problems, the invention adopts the following technical scheme:
a method for improving grid-connected operation capacity of a doubly-fed wind turbine generator under grid fault comprises the following steps:
s1, real timeDetecting terminal voltage amplitude U of doubly-fed wind generator setsmAnd rotor current amplitude Irm；
S2, when a three-phase short circuit fault occurs on a return wire of the wind turbine generator, the terminal voltage of the double-fed wind turbine generator is reduced, and the terminal voltage UsmNot more than 0.9p.u. and rotor current IrmWhen the voltage is more than or equal to 2.0p.u., a rotor Crowbar circuit is put into and a rotor side converter is locked, and the terminal voltage U issmNot more than 0.9p.u. and rotor current IrmThe time is more than or equal to 2.0p.u. is the starting time of the fault;
s3, when the rotor current I of the doubly-fed wind turbine generatorrmWhen the voltage is less than or equal to 1.9p.u., quitting a Crowbar circuit of a rotor of the doubly-fed wind turbine generator and restarting a rotor-side converter, and simultaneously respectively setting active and reactive control instruction values of the rotor-side converter to be Psc、QscAnd implementing control;
s4, according to the active and reactive control instruction value Psc、QscTerminal voltage U of doubly-fed wind turbine generator after calculation and implementation controlsc；
S5, to control the back-end voltage UscDetermining minimum grid-connected duration t of double-fed wind turbine generator under grid faultd,min；
S6, if at tf＜td,minDuring the period, the voltage of the machine terminal of the double-fed wind power generator set is increased by detecting that the grid fault is cleared, and U issmWhen the current is more than 0.9p.u., the active and reactive control instruction values of the rotor side converter are set to be Psn、QsnAnd the doubly-fed wind turbine generator recovers normal operation, wherein Psn、QsnThe control instruction values are active control instruction values and reactive control instruction values before the power grid fails; t is tf＝t-tf0，tf0If the time is the fault occurrence time, t is the real-time acquisition time, otherwise, S7 is executed;
s7, the doubly-fed wind turbine generator always keeps grid-connected operation, and the control instruction value is kept at Psc、QscDetecting whether the operating parameters of the doubly-fed wind turbine generator such as the stator and rotor current, the rotor voltage, the generator rotating speed and the direct current voltage exceed the allowable range, and if the operating parameters exceed the allowable range, when t is more than td,minThen the double-fed wind turbine generator is withdrawn from the power grid,if the parameters are not out of limit, the terminal voltage of the doubly-fed wind generator set is increased to U until the grid fault is clearedsmWhen the current is more than 0.9p.u., setting the active and reactive control instruction values of the rotor side converter to be Psn、QsnAnd the double-fed wind turbine generator recovers normal operation.
Preferably, in step S2, the active and reactive control commands P of the doubly-fed wind turbine rotor-side convertersc、QscCalculated as follows:
Figure BDA0002228334100000031
Figure BDA0002228334100000032
wherein the coefficient K1、K2、K3、K4、K5、K6、K7、K8Respectively as follows:
Figure BDA0002228334100000041
Figure BDA0002228334100000042
Figure BDA0002228334100000043
Figure BDA0002228334100000044
Figure BDA0002228334100000045
Figure BDA0002228334100000046
K7＝(λrc1-λpf1)2/(λrc2-λpf2)2
Figure BDA0002228334100000047
wherein the content of the first and second substances,
Figure BDA0002228334100000048
Figure BDA0002228334100000049
Figure BDA00022283341000000410
Figure BDA00022283341000000411
Figure BDA00022283341000000412
Figure BDA00022283341000000413
in the formula, Xg′＝(1-α)Xl/2+Xg+XTg；Xd′＝αXl/2+XTd；Xl'＝α(1-α)Xl/2；XTgAnd XTdRespectively serving as the reactance of a system side transformer and the reactance of a booster transformer of the double-fed wind turbine generator; xlThe line reactance is between the step-up transformer of the double-fed wind turbine generator and a system side transformer; double-fed wind power generation with alpha as fault point distanceThe distance between the generator set step-up transformer and the total length of the wind turbine generator set and the power grid connecting line is proportional to the total length of the wind turbine generator set and the power grid connecting line; u shapegIs the system voltage amplitude; xgIs an equivalent reactance; rfA transition resistance that is a three-phase short circuit; rs、Xs、ZsThe equivalent resistance, reactance and impedance of the stator of the doubly-fed wind turbine generator are respectively; xmThe double-fed wind turbine generator is an excitation reactor; i isr,maxThe maximum running current of the rotor of the doubly-fed wind turbine generator is obtained.
Preferably, in step S4, controlling the back-end voltage U is performedscThe maximum grid-connected point voltage which can be achieved through the control of the double-fed wind turbine generator is calculated according to the following formula:
Figure BDA0002228334100000051
in the formula (I), the compound is shown in the specification,
Figure BDA0002228334100000052
preferably, in step S5, the minimum grid-connection duration t of the doubly-fed wind turbine generator under the grid fault after the control is implementedd,minIt can be calculated as follows:
Figure BDA0002228334100000053
aiming at the defects of the prior art, the invention provides a method for improving the grid-connected operation capacity of a double-fed wind turbine generator under the power grid fault, and the method improves the grid-connected operation capacity of the double-fed wind turbine generator under the power grid fault from 2 aspects of increasing the voltage of the double-fed wind turbine generator under the power grid fault and improving the minimum duration calculation method, realizes fault ride-through of the double-fed wind turbine generator, and supports the application of the double-fed wind turbine generator in power grid operation control. Different from the prior art, the method fully considers the influence of the power adjustment of the double-fed wind turbine generator on the grid voltage during the grid fault, fully considers the influence of the grid voltage rise on the minimum grid-connection duration of the double-fed wind turbine generator during the grid fault, can improve the generator terminal voltage of the double-fed wind turbine generator under the grid fault, and prolongs the grid-connection operation time of the double-fed wind turbine generator under the grid fault, so that the continuous grid-connection operation capacity of the double-fed wind turbine generator under the grid fault is improved, and effective technical measures can be provided for the operation control of a high-proportion wind power system.
Drawings
For purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made in detail to the present invention as illustrated in the accompanying drawings, in which:
fig. 1 is a flowchart of a method for improving grid-connected operation capability of a doubly-fed wind turbine generator set under a power grid fault, disclosed by the invention;
fig. 2 is a schematic diagram of a grid-connected system of a doubly-fed wind turbine.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1, the invention discloses a method for improving grid-connected operation capability of a doubly-fed wind turbine generator under a power grid fault, which comprises the following steps:
s1, detecting terminal voltage amplitude U of doubly-fed wind generator set in real timesmAnd rotor current amplitude Irm；
S2, when a three-phase short circuit fault occurs on a return wire of the wind turbine generator, the terminal voltage of the double-fed wind turbine generator is reduced, and the terminal voltage UsmNot more than 0.9p.u. and rotor current IrmWhen the voltage is more than or equal to 2.0p.u., a rotor Crowbar circuit is put into and a rotor side converter is locked, and the terminal voltage U issmNot more than 0.9p.u. and rotor current IrmThe time is more than or equal to 2.0p.u. is the starting time of the fault;
s3, when the rotor current I of the doubly-fed wind turbine generatorrmWhen the voltage is less than or equal to 1.9p.u., quitting a Crowbar circuit of a rotor of the doubly-fed wind turbine generator and restarting a rotor-side converter, and simultaneously respectively setting active and reactive control instruction values of the rotor-side converter to be Psc、QscAnd implementing control;
s4, according to the active and reactive control instruction value Psc、QscTerminal voltage U of doubly-fed wind turbine generator after calculation and implementation controlsc；
S5, to control the back-end voltage UscDetermining minimum grid-connected duration t of double-fed wind turbine generator under grid faultd,min；
S6, if at tf＜td,minDuring the period, the voltage of the machine terminal of the double-fed wind power generator set is increased by detecting that the grid fault is cleared, and U issmWhen the current is more than 0.9p.u., the active and reactive control instruction values of the rotor side converter are set to be Psn、QsnAnd the doubly-fed wind turbine generator recovers normal operation, wherein Psn、QsnThe control instruction values are active control instruction values and reactive control instruction values before the power grid fails; t is tf＝t-tf0，tf0If the time is the fault occurrence time, t is the real-time acquisition time, otherwise, S7 is executed;
s7, the doubly-fed wind turbine generator always keeps grid-connected operation, and the control instruction value is kept at Psc、QscDetecting whether the operating parameters of the doubly-fed wind turbine generator such as the stator and rotor current, the rotor voltage, the generator rotating speed and the direct current voltage exceed the allowable range (the power grid operating rule has the allowable operating ranges of the voltage and the current, and the allowable ranges are different at different voltage levels and power grid scales), if the operating parameters exceed the allowable range, when t is more than td,minAnd then the doubly-fed wind turbine generator is withdrawn from the power grid, if the parameters are not out of limit, the voltage of the machine terminal of the doubly-fed wind turbine generator is increased to U until the power grid fault is eliminated, and the voltage of the machine terminal of the doubly-fed wind turbine generator is increased to UsmWhen the current is more than 0.9p.u., setting the active and reactive control instruction values of the rotor side converter to be Psn、QsnAnd the double-fed wind turbine generator recovers normal operation.
The invention is different from the prior art in that:
1) in the prior art, the power control capability of the doubly-fed wind turbine generator is determined by using the machine terminal voltage at the moment of failure, the machine terminal voltage of the doubly-fed wind turbine generator under the power grid failure is improved under the condition of the power control capability, and the change of the machine terminal voltage after the control implementation is ignored, so that the control effect is limited, the grid-connected operation of the doubly-fed wind turbine generator under the power grid failure is limited, the control reference value is difficult to track, and even the oscillation or instability of the generator is caused; according to the invention, the generator terminal voltage U of the doubly-fed wind turbine generator is calculated and controlled at S4scIn time, the double-fed wind turbine generator setThe relation between the output power and the power flow distribution of the power grid and the relation between the generator terminal voltage and the output power of the double-fed wind turbine generator are solved in a simultaneous mode, so that the influence of the power adjustment of the double-fed wind turbine generator on the generator terminal voltage through source network coupling during the power grid fault is fully considered, the generator terminal voltage of the double-fed wind turbine generator under the power grid fault can be further improved, the safe operation of the double-fed wind turbine generator under the power grid fault is facilitated, and the continuous grid-connected operation capacity of the double-fed wind turbine generator under.
2) In the prior art, the minimum grid-connected duration time of the doubly-fed wind turbine generator is determined by using the machine terminal voltage at the moment of the fault, and the minimum grid-connected duration time is taken as the basis for the grid disconnection of the doubly-fed wind turbine generator under the grid fault, but because the doubly-fed wind turbine generator outputs reactive power to support the grid voltage during the grid fault, the machine terminal voltage of the doubly-fed wind turbine generator continuously rises after the fault, namely the voltage at the moment of the fault is the minimum value of the voltage during the fault, so that the determined minimum grid-connected duration time is necessarily smaller, and the grid-connected operation of the doubly-; according to the method, the influence of the grid voltage rise on the minimum grid-connection duration of the double-fed wind turbine generator during the grid fault is fully considered, the minimum grid-connection duration is calculated by using the generator-side voltage of the double-fed wind turbine generator after control is implemented, the grid-connection operation time of the double-fed wind turbine generator under the grid fault can be prolonged, and therefore the continuous grid-connection operation capacity of the double-fed wind turbine generator under the grid fault is improved.
In specific implementation, active and reactive control instructions P of rotor-side converter of doubly-fed wind turbine generatorsc、QscCalculated as follows:
Figure BDA0002228334100000071
Figure BDA0002228334100000072
wherein the coefficient K1、K2、K3、K4、K5、K6、K7、K8Respectively as follows:
Figure BDA0002228334100000073
Figure BDA0002228334100000074
Figure BDA0002228334100000075
Figure BDA0002228334100000076
Figure BDA0002228334100000077
Figure BDA0002228334100000078
K7＝(λrc1-λpf1)2/(λrc2-λpf2)2
Figure BDA0002228334100000079
wherein the content of the first and second substances,
Figure BDA00022283341000000710
Figure BDA0002228334100000081
Figure BDA0002228334100000082
Figure BDA0002228334100000083
Figure BDA0002228334100000084
Figure BDA0002228334100000085
in the formula, Xg′＝(1-α)Xl/2+Xg+XTg；Xd′＝αXl/2+XTd；Xl'＝α(1-α)Xl/2；XTgAnd XTdRespectively serving as the reactance of a system side transformer and the reactance of a booster transformer of the double-fed wind turbine generator; xlThe line reactance is between the step-up transformer of the double-fed wind turbine generator and a system side transformer; alpha is the proportion of the distance between a fault point and a booster transformer of the doubly-fed wind turbine generator set in the total length of the line; u shapegIs the system voltage amplitude; xgIs an equivalent reactance; rfA transition resistance that is a three-phase short circuit; rs、Xs、ZsThe equivalent resistance, reactance and impedance of the stator of the doubly-fed wind turbine generator are respectively; xmThe double-fed wind turbine generator is an excitation reactor; i isr,maxThe maximum running current of the rotor of the doubly-fed wind turbine generator is obtained.
In specific implementation, the control of the voltage U at the back-end terminal is implementedscThe maximum grid-connected point voltage which can be achieved through the control of the double-fed wind turbine generator is calculated according to the following formula:
Figure BDA0002228334100000086
in the formula (I), the compound is shown in the specification,
Figure BDA0002228334100000087
in specific implementation, the minimum grid-connected duration of the doubly-fed wind turbine generator under the power grid fault after the control is implemented can be calculated according to the following formula:
Figure BDA0002228334100000088
the method aims at the problems that when a power grid fails, the existing method is limited by the calculation accuracy of the control quantity, the control effect is limited, the control error is large, the control capability and the safety margin of the double-fed wind turbine generator cannot be fully exerted, the capability of the double-fed wind turbine generator for continuous grid-connected operation under the power grid failure is limited, the application of the double-fed wind turbine generator in the power grid operation control is limited, and the power grid safety problem can be caused by the fact that the double-fed wind turbine generator is disconnected from the power grid too early. The method fully considers the influence of the power adjustment of the double-fed wind turbine generator on the grid voltage during the grid fault, fully considers the influence of the grid voltage rise on the minimum grid-connection duration of the double-fed wind turbine generator during the grid fault, provides a method for determining the active and reactive control reference values of the double-fed wind turbine generator according to the effect after control implementation, and provides a calculation method of the generator terminal voltage and the minimum grid-connection duration of the double-fed wind turbine generator after control implementation.
Finally, it is noted that the above-mentioned embodiments illustrate rather than limit the invention, and that, while the invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (3)

1. A method for improving grid-connected operation capacity of a doubly-fed wind turbine generator under grid fault is characterized by comprising the following steps:
s1, detecting terminal voltage amplitude U of doubly-fed wind generator set in real timesmAnd rotor current amplitude Irm；
S2, when a three-phase short circuit fault occurs on a return wire of the wind turbine generator, the terminal voltage of the double-fed wind turbine generator is reduced, and the terminal voltage UsmNot more than 0.9p.u. and rotor current IrmWhen the voltage is more than or equal to 2.0p.u., a rotor Crowbar circuit is put into and a rotor side converter is locked, and the terminal voltage U issmNot more than 0.9p.u. and rotor current IrmThe time is more than or equal to 2.0p.u. is the starting time of the fault;
s3, when the rotor current I of the doubly-fed wind turbine generatorrmWhen the voltage is less than or equal to 1.9p.u., quitting a Crowbar circuit of a rotor of the doubly-fed wind turbine generator and restarting a rotor-side converter, and simultaneously respectively setting active and reactive control instruction values of the rotor-side converter to be Psc、QscAnd implementing control;
active and reactive control instruction P of rotor-side converter of doubly-fed wind turbine generatorsc、QscCalculated as follows:
Figure FDA0002886154960000011
Figure FDA0002886154960000012
wherein the coefficient K1、K2、K3、K4、K5、K6、K7、K8Respectively as follows:
Figure FDA0002886154960000013
Figure FDA0002886154960000014
Figure FDA0002886154960000015
Figure FDA0002886154960000016
Figure FDA0002886154960000017
Figure FDA0002886154960000018
K7＝(λrc1-λpf1)2/(λrc2-λpf2)2
Figure FDA0002886154960000019
wherein the content of the first and second substances,
Figure FDA00028861549600000110
Figure FDA0002886154960000021
Figure FDA0002886154960000022
Figure FDA0002886154960000023
Figure FDA0002886154960000024
Figure FDA0002886154960000025
in the formula, Xg′＝(1-α)Xl/2+Xg+XTg；Xd′＝αXl/2+XTd；Xl'＝α(1-α)Xl/2；XTgAnd XTdRespectively serving as the reactance of a system side transformer and the reactance of a booster transformer of the double-fed wind turbine generator; xlThe line reactance is between the step-up transformer of the double-fed wind turbine generator and a system side transformer; alpha is the proportion of the distance between the fault point and the booster transformer of the doubly-fed wind turbine generator set in the total length of the wind turbine generator set and the power grid connecting line; u shapegIs the system voltage amplitude; xgIs an equivalent reactance; rfA transition resistance that is a three-phase short circuit; rs、Xs、ZsThe equivalent resistance, reactance and impedance of the stator of the doubly-fed wind turbine generator are respectively; xmThe double-fed wind turbine generator is an excitation reactor; i isr,maxThe maximum running current of the rotor of the doubly-fed wind turbine generator is obtained;
s4, according to the active and reactive control instruction value Psc、QscTerminal voltage U of doubly-fed wind turbine generator after calculation and implementation controlsc；
S5, to control the back-end voltage UscDetermining minimum grid-connected duration t of double-fed wind turbine generator under grid faultd,min；
S6, if at tf＜td,minDuring the period, the voltage of the machine terminal of the double-fed wind power generator set is increased by detecting that the grid fault is cleared, and U issmWhen the current is more than 0.9p.u., the active and reactive control instruction values of the rotor side converter are set to be Psn、QsnAnd the doubly-fed wind turbine generator recovers normal operation, wherein Psn、QsnThe control instruction values are active control instruction values and reactive control instruction values before the power grid fails; t is tf＝t-tf0，tf0T is the time of failure occurrence and t is the time of real-time acquisitionOtherwise, executing S7;
s7, the doubly-fed wind turbine generator always keeps grid-connected operation, and the control instruction value is kept at Psc、QscDetecting whether the operating parameters of the doubly-fed wind turbine generator such as the stator and rotor current, the rotor voltage, the generator rotating speed and the direct current voltage exceed the allowable range, and if the operating parameters exceed the allowable range, when t is more than td,minAnd then the doubly-fed wind turbine generator is withdrawn from the power grid, if the parameters are not out of limit, the voltage of the machine terminal of the doubly-fed wind turbine generator is increased to U until the power grid fault is eliminated, and the voltage of the machine terminal of the doubly-fed wind turbine generator is increased to UsmWhen the current is more than 0.9p.u., setting the active and reactive control instruction values of the rotor side converter to be Psn、QsnAnd the double-fed wind turbine generator recovers normal operation.
2. The method for improving the grid-connected operation capacity of the doubly-fed wind turbine generator under the grid fault according to claim 1, wherein in the step S4, the control of the back-end voltage U is implementedscThe maximum grid-connected point voltage which can be achieved through the control of the double-fed wind turbine generator is calculated according to the following formula:
Figure FDA0002886154960000031
in the formula (I), the compound is shown in the specification,
Figure FDA0002886154960000032
3. the method for improving the grid-connected operation capacity of the doubly-fed wind turbine generator under the grid fault according to claim 2, wherein in the step S5, the minimum grid-connected duration t of the doubly-fed wind turbine generator under the grid fault after the control is implementedd,minIt can be calculated as follows:
Figure FDA0002886154960000033
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CN113125953B (en) * 2020-01-15 2022-12-09 江苏龙源风电技术培训有限公司 Wind generating set fault judgment method and fault judgment equipment thereof
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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102457195A (en) * 2010-11-02 2012-05-16 上海电气风电设备有限公司 Power grid failure traversing system and method of 2 MW and more than 2 MW double-fed wind generating set complete machine
CN103296682A (en) * 2013-05-09 2013-09-11 国家电网公司 Multiple spatial and temporal scale gradually-advancing load dispatching mode designing method
CN103326368A (en) * 2013-06-13 2013-09-25 国家电网公司 Dynamic reactive current direct control method by doubly-fed wind turbine generator set during grid fault
CN106021754A (en) * 2016-05-26 2016-10-12 重庆大学 Probabilistic power flow algorithm of hybrid power grid taking adjustment strategy of VSC reactive power constraints into consideration
CN108565897A (en) * 2018-06-20 2018-09-21 清华大学 Power electronics generates electricity by way of merging two or more grid systems the Transient Stability Control method and system of unit
CN109038620A (en) * 2018-09-17 2018-12-18 浙江运达风电股份有限公司 Double-fed fan motor unit frequency modulation and pressure regulation control method for coordinating under a kind of weak grid conditions
CN109066791A (en) * 2018-08-31 2018-12-21 中国电力科学研究院有限公司 A kind of determination method and apparatus of wind-powered electricity generation simulation abandonment sequence
CN109524994A (en) * 2018-12-25 2019-03-26 重庆大学 A kind of control method and system improving double-fed fan motor interconnected electric power system false voltage

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2926002B1 (en) * 2012-11-30 2019-01-23 Vestas Wind Systems A/S Power plant generation system, method for controlling wind turbine generators, power plant controller and wind turbine generator

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102457195A (en) * 2010-11-02 2012-05-16 上海电气风电设备有限公司 Power grid failure traversing system and method of 2 MW and more than 2 MW double-fed wind generating set complete machine
CN103296682A (en) * 2013-05-09 2013-09-11 国家电网公司 Multiple spatial and temporal scale gradually-advancing load dispatching mode designing method
CN103326368A (en) * 2013-06-13 2013-09-25 国家电网公司 Dynamic reactive current direct control method by doubly-fed wind turbine generator set during grid fault
CN106021754A (en) * 2016-05-26 2016-10-12 重庆大学 Probabilistic power flow algorithm of hybrid power grid taking adjustment strategy of VSC reactive power constraints into consideration
CN108565897A (en) * 2018-06-20 2018-09-21 清华大学 Power electronics generates electricity by way of merging two or more grid systems the Transient Stability Control method and system of unit
CN109066791A (en) * 2018-08-31 2018-12-21 中国电力科学研究院有限公司 A kind of determination method and apparatus of wind-powered electricity generation simulation abandonment sequence
CN109038620A (en) * 2018-09-17 2018-12-18 浙江运达风电股份有限公司 Double-fed fan motor unit frequency modulation and pressure regulation control method for coordinating under a kind of weak grid conditions
CN109524994A (en) * 2018-12-25 2019-03-26 重庆大学 A kind of control method and system improving double-fed fan motor interconnected electric power system false voltage

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
故障电网下双馈风电系统运行技术研究综述;年珩，程鹏，贺益康;《中国电机工程学报》;20150820;第4184-4192页 *

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