CN116131276A - Offshore wind power reactive power compensation optimization calculation method and system based on power factors - Google Patents
Offshore wind power reactive power compensation optimization calculation method and system based on power factors Download PDFInfo
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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
- H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
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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
- H02J3/381—Dispersed generators
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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
- H02J3/50—Controlling the sharing of the out-of-phase component
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
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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
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
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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
- 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
- H02J2300/28—The renewable source being wind energy
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- 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 disclosure belongs to the technical field of reactive power compensation, and in particular relates to a power factor-based offshore wind power reactive power compensation optimization calculation method and system, comprising the following steps: acquiring the fan type and the running state of the offshore wind turbine; according to the acquired fan type and the running state, constructing an offshore wind power equivalent model; based on the constructed equivalent model, determining the alternating current bus voltage of the flexible direct-current end converter station; judging the selection range of the fan power factor according to the obtained alternating current bus voltage; and calculating fluctuation of reactive power shortage of the offshore wind turbine according to the selection range of the power factors of the fans, and configuring reactive power compensation of the fans.
Description
Technical Field
The disclosure belongs to the technical field of reactive power compensation, and particularly relates to a power factor-based offshore wind power reactive power compensation optimization calculation method and system.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
With the continuous expansion of offshore wind power scale and the increasing of offshore distance, flexible direct current transmission systems are applied to offshore wind farms. Unlike onshore wind power, the charging power of the alternating-current submarine cable is about 8-10 times that of the overhead line, so that the reactive power of the offshore wind farm is excessive, and the offshore converter station is singly used as main reactive power compensation equipment, so that the aim that the voltage qualification of all wind farms cannot be met is met.
Disclosure of Invention
In order to solve the problems, the present disclosure provides a power factor-based offshore wind power reactive compensation optimization calculation method and system, which are used for performing output characteristic analysis on a direct-drive fan with an adjustable power factor, configuring a corresponding reactive compensation device according to various running conditions of a wind farm, and ensuring the maximum dynamic reactive margin of an offshore converter station.
According to some embodiments, a first scheme of the present disclosure provides an offshore wind power reactive power compensation optimization calculation method based on power factors, which adopts the following technical scheme:
a power factor-based offshore wind power reactive power compensation optimization calculation method comprises the following steps:
acquiring the fan type and the running state of the offshore wind turbine;
according to the acquired fan type and the running state, constructing an offshore wind power equivalent model;
based on the constructed equivalent model, determining the alternating current bus voltage of the flexible direct-current end converter station;
judging the selection range of the fan power factor according to the obtained alternating current bus voltage;
and calculating fluctuation of reactive power shortage of the offshore wind turbine according to the selection range of the power factors of the fans, and configuring reactive power compensation of the fans.
As a further technical definition, the reactive power loss of the offshore wind power is that of a fan-side box-type transformer and an offshore booster station, and is related to the active power output by a wind farm; the larger the active power output by the wind farm is, the more reactive power loss of the offshore wind power is.
As further technical limitation, when the isolated network access of the new energy cluster is flexible and straight, the control mode of the sending end converter station is fixed alternating voltage and fixed alternating frequency control, and the alternating voltage controlled by the sending end converter station is the busbar voltage at the alternating side; the alternating-current side bus voltage is equivalent to a balance node in the new energy cluster system.
As a further technical definition, the constraint conditions of the offshore wind power equivalent model include output voltage modulation ratio constraint of the voltage source converter station, common connection point node voltage constraint, converter station output current constraint and constraint by maximum direct current line current limit.
Further, defining dynamic reactive margin of the converter station as the shortest distance from the operating point of the converter station to the upper and lower boundaries in the output state of the current new energy; the dynamic reactive margin of the converter station is maximized by changing the alternating current bus when the converter station is in steady state operation.
As a further technical limitation, the reactive power sources in the wind power plant are wind power generators, alternating current submarine cables, transformers and converter stations, when the reactive power shortage of the offshore wind turbine is calculated, according to the current running state of the wind turbine, the lack of inductive reactive power is indicated when the reactive power shortage is a negative number, and the lack of capacitive reactive power is indicated when the reactive power shortage is a positive number.
As a further technical limitation, the offshore wind turbine reactive power shortage Q q Is Q q ＝-Q WFi -Q C35i -Q C220i +Q Li +Q L35i +Q L220i The method comprises the steps of carrying out a first treatment on the surface of the Wherein Q is WFi Output reactive power for wind power generator, Q C35i 、Q C220i Charging power for AC sea cable, Q Li 、Q L35i 、Q L220i The reactive power loss of the transformer and the AC submarine cable is respectively.
According to some embodiments, a second scheme of the present disclosure provides an offshore wind power reactive power compensation optimization computing system based on power factors, which adopts the following technical scheme:
an offshore wind power reactive power compensation optimization computing system based on power factors, comprising:
the acquisition module is configured to acquire the fan type and the running state of the offshore wind turbine;
the construction module is configured to construct an offshore wind power equivalent model according to the acquired fan type and the running state;
the judging module is configured to determine the voltage of the alternating current bus of the flexible direct-current end converter station based on the constructed equivalent model; judging the selection range of the fan power factor according to the obtained alternating current bus voltage;
and the calculation module is configured to calculate fluctuation of reactive power shortage of the offshore wind turbine according to the selection range of the power factor of the fan and configure reactive power compensation of the fan.
According to some embodiments, a third aspect of the present disclosure provides a computer-readable storage medium, which adopts the following technical solutions:
a computer readable storage medium having stored thereon a program which when executed by a processor implements the steps in the power factor based offshore wind power reactive compensation optimization calculation method according to the first aspect of the present disclosure.
According to some embodiments, a fourth aspect of the present disclosure provides an electronic device, which adopts the following technical solutions:
an electronic device comprising a memory, a processor and a program stored on the memory and executable on the processor, the processor implementing the steps in the power factor based offshore wind power reactive compensation optimization calculation method according to the first aspect of the disclosure when the program is executed.
Compared with the prior art, the beneficial effects of the present disclosure are:
the alternating-current submarine cable charging power and the reactive power control capability of the converter station are quantized, and on the premise that the maximum dynamic reactive power margin of the converter station is ensured, the alternating-current bus voltage reference value in the operation of a wind field is selected; aiming at the fluctuation condition of reactive power shortage of the system under two fan operation methods, the capacity of the corresponding reactive power compensation device of the wind field is determined by taking the minimum investment as the target.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate and explain the exemplary embodiments of the disclosure and together with the description serve to explain the disclosure, and do not constitute an undue limitation on the disclosure.
FIG. 1 is a flowchart of a power factor based offshore wind power reactive compensation optimization calculation method in a first embodiment of the disclosure;
FIG. 2 is a schematic diagram of output characteristics of a fan with different power factors in accordance with a first embodiment of the present disclosure;
FIG. 3 is a schematic diagram of a distributed parameter model in accordance with a first embodiment of the present disclosure;
fig. 4 is a schematic diagram of an n-type equivalent model in a first embodiment of the disclosure;
FIG. 5 is a schematic diagram of a 400MW wind farm alternating current sea cable (10 km) along line voltage in an embodiment of the disclosure;
FIG. 6 is a schematic diagram of a 300MW wind farm alternating current sea cable (10 km) along line voltage in an embodiment of the disclosure;
FIG. 7 is a schematic diagram of a 400MW wind farm alternating current sea cable (20 km) along line voltage in an embodiment of the disclosure;
FIG. 8 is a schematic diagram of a 300MW wind farm alternating current sea cable (20 km) along line voltage in an embodiment of the disclosure;
FIG. 9 is a schematic diagram of a 400MW wind farm alternating current sea cable (30 km) along line voltage in an embodiment of the disclosure;
FIG. 10 is a schematic diagram of a 300MW wind farm alternating current sea cable (30 km) along line voltage in an embodiment of the disclosure;
FIG. 11 is a schematic view of a wind power cluster topology in accordance with a first embodiment of the disclosure;
FIG. 12 is a schematic diagram of the voltage variation of the key nodes of the H1 wind farm in the first embodiment of the disclosure;
FIG. 13 is a schematic diagram of voltage variation of a key node of an H2 wind farm in accordance with an embodiment of the disclosure;
FIG. 14 is a schematic diagram of a voltage change at a key node of an H3 wind farm in accordance with one embodiment of the disclosure;
fig. 15 is a schematic diagram of an equivalent circuit model of an ac submarine cable according to the first embodiment of the present disclosure;
FIG. 16 is a schematic diagram of reactive trend of the system without compensation in accordance with one embodiment of the present disclosure;
fig. 17 is a schematic diagram of a new energy cluster access single-ended VSC-HVDC equivalent model in accordance with embodiment one of the present disclosure;
FIG. 18 is a schematic diagram of steady state operating ranges at voltage references 0.97p.u., 1.07p.u., in embodiment one of the present disclosure;
FIG. 19 is a schematic diagram of steady state operating range at a voltage reference of 1.0p.u. in an embodiment of the disclosure;
fig. 20 is a schematic diagram of a dynamic reactive margin of a converter station in accordance with an embodiment of the present disclosure;
FIG. 21 is a flow chart of a configuration method in a first embodiment of the present disclosure;
fig. 22 is a block diagram of a power factor-based offshore wind power reactive compensation optimization computing system in a second embodiment of the disclosure.
Detailed Description
The disclosure is further described below with reference to the drawings and examples.
It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
Embodiments of the present disclosure and features of embodiments may be combined with each other without conflict.
Example 1
The embodiment of the disclosure first introduces an offshore wind power reactive power compensation optimization calculation method based on power factors.
The offshore wind power reactive power compensation optimization calculation method based on the power factors shown in fig. 1 comprises the following steps:
acquiring the fan type and the running state of the offshore wind turbine;
according to the acquired fan type and the running state, constructing an offshore wind power equivalent model;
based on the constructed equivalent model, determining the alternating current bus voltage of the flexible direct-current end converter station;
judging the selection range of the fan power factor according to the obtained alternating current bus voltage;
and calculating fluctuation of reactive power shortage of the offshore wind turbine according to the selection range of the power factors of the fans, and configuring reactive power compensation of the fans.
With the continuous progress of wind generating set technology, permanent magnet direct-driven synchronous wind generating sets and doubly-fed wind generating sets are developed into main stream types in the wind power plant at present, and meanwhile, the two types of the wind generating sets are reactive power supplies, so that reactive power can be generated and absorbed. Typically, the fan reactive voltage control is a constant power factor control or a constant voltage control, and fan constant power factor control is mainly considered herein. According to the wind power plant access regulation of GB-T19963.1-2021, the wind power generation set required to be installed is adjustable within the range of 0.95-0.95 of advance power factor.
In this embodiment, considering the permanent magnet direct-drive fan, the direct-drive fan is connected to the power grid through the full-power converter, the voltage and the frequency of the converter side and the voltage and the frequency of the grid side are decoupled mutually, and the grid-connected electrical characteristic of the fan and the generator relationship are not great, and mainly depend on the technical performance of the grid-side converter.
Under the limitation of the maximum allowable current of the converter, the rated apparent power of the single wind turbine generator is fixed, and the output apparent power cannot exceed the rated value. In a short time, the converter can work at 110% rated capacity, and the reactive power generating capacity of the converter can meet the following formula:
therefore, the upper and lower limits of the output reactive power of the direct-drive fan are as follows:
wherein S is max Is the maximum value of apparent power, typically 110% of nominal value.
The calculated reactive limit range of the fan and the output characteristics of the fan with different power factors are shown in fig. 2, wherein a, b, c, d is the reactive limit range.
For offshore wind power clusters, the charging power of the alternating current submarine cable is a stable reactive power source, so that as the conveying distance of the submarine cable increases, a distribution parameter equivalent circuit is adopted when the capacitance effect of the submarine cable in alternating current withstand voltage is analyzed, as shown in fig. 3 and 4 respectively.
Knowing the impedance z per unit length 1 And admittance per unit length y 1 The voltage and current at any point along the line can be calculated according to the terminal voltage and current:
Converting into an n-type equivalent circuit to obtain:
when an ac submarine cable is connected to a converter station, the converter station corresponds to a stable ac power source, and therefore submarine cable voltage is related to submarine cable parameters, submarine cable length, and delivery power. Through calculation and analysis, when different active powers are transmitted, the influence of the submarine cable length on the line voltage is achieved.
Assuming that two wind fields of 300MW and 400MW exist, the voltage change along the submarine cable when the submarine cable length is 10km, 20km and 30km is calculated, and the calculation results are shown in fig. 5, 6, 7, 8, 9 and 10.
Assuming that the H1, H2 and H3 are respectively wind fields of 400MW, 300MW and 300MW, and a total of 200 direct-drive fans with single-machine capacity of 5MW, each wind field is provided with a 220kV offshore booster station, the main transformer design scale is respectively 2 x 240MVA, 2 x 180MVA and 2 x 180MVA, and the main transformer design scale is connected to an offshore converter station through 2 times 220kV submarine cables (2 x 10km, 2 x 20km and 2 x 30 km) after boosting, and the topological structure is shown in figure 11.
For the inside of the offshore wind farm, the reactive power loss is mostly reactive power loss such as a fan-side box-type transformer, an offshore booster station and the like, and is mainly related to active power output by the wind farm, and the larger the output power is, the more the reactive power loss is. In general, in full-firing situations, the reactive losses of the wind farm are maximum, while in zero-firing situations, the reactive losses are minimum.
In a wind farm, the number of fans connected to the tail ends of the feeder lines is smaller, and the current is smaller, so that reactive power consumption is smaller. The number of fans at the head end of the feeder is more, and reactive power loss is larger. However, in the whole, the voltage difference of each fan of one line is not large, so that the terminal fan terminal voltage, a 35kV bus, a main transformer high-voltage side and a converter station bus are selected as important nodes, and the voltage fluctuation range is respectively shown in fig. 12, 13 and 14 in the process of observing the active output change; the voltage reactive power distribution characteristics of the offshore wind farm are that the voltage on the offshore cable can rise due to the high charging power of the offshore cable, but the reactive power consumption of the offshore cable and the inside of the wind farm is increased along with the increase of the active power output, so that the voltage can be reduced. When the output force is large, the 35kV bus voltage may drop below the rated voltage, and the 35kV bus voltage is smaller than the fan terminal voltage in general.
In a wind power plant, an alternating current submarine cable is a stable reactive power source, reactive power is mainly influenced by line voltage, reactive power consumption is mainly influenced by active power transmission, and a submarine cable equivalent circuit model is shown in fig. 15.
Reactive charging capability of submarine cable
Reactive loss of submarine cable
Assuming that the fans are operated with a unit power factor and the voltage value of the alternating current bus is 1.0p.u., the reactive power loss and the charging power of the wind field 35kV system and the wind field 220kV system are calculated as shown in tables 1 and 2.
TABLE 1 wind farm 35kV System reactive analysis results statistics
Table 2 wind farm 220kV system reactive analysis results statistics
The trend of reactive power change from 0 to full of the wind farm system without accounting for high reactance and SVG is shown in fig. 16.
The control mode of the new energy cluster isolated network access soft-straightening time transmitting-end converter station is fixed alternating voltage and fixed alternating frequency control, the alternating voltage controlled by the transmitting-end converter station is alternating-side bus voltage, the alternating voltage is equivalent to a balance node in the new energy cluster system, but the alternating-side bus voltage cannot be regarded as a simple infinite node, but an infinite node meeting the operation constraint condition of the converter station is needed, so that the steady-state operation range of the system is needed to be studied, namely the reactive margin in the current operation state can be quantified, and a soft-straightening converter station single-end equivalent model is shown in fig. 17.
Considering the constraint of the actual capacity of the converter station, since the flexible direct-current end converter station can realize independent control of active power and reactive power, the active power and reactive power which are transmitted to the flexible direct by the new energy cluster must be limited in a certain specific range of the PQ plane. The steady-state operation range of the voltage source converter station at this time refers to the variation range of active power and reactive power which are transmitted from the new energy cluster isolated network system to the alternating current bus of the converter station. In order to study the operating ranges of the active power Ps and the reactive power Qs injected into the bus bar node of the converter station, the operating ranges of Ps and Qs are analyzed with the active power Pv and the reactive power Qv output at the v point taken as intermediate variables.
In combination with a sending end converter station control mode, comprehensively considering various constraints of a converter station PQ operation interval, the method comprises the following steps:
(1) Output voltage modulation ratio m constraint of voltage source converter station
The voltage at point V and the output power are known, and the voltage at point delta can be obtained:
the voltage source output voltage modulation ratio m is generally defined as the fundamental phase voltage amplitude over delta divided by U dc /2：
Wherein μ=0.866 is taken.
Considering constraint conditions of the converter in actual operation, the output voltage modulation ratio m needs to be checked:
0.85≤m≤1.0
(2) Common junction node voltage constraints
Calculating alternating-current side bus U of converter station s ：
Because the voltage stabilization depends on the dynamic reactive power adjustment of the converter station, the actual running condition in engineering is considered, and the voltage meets the grid-connected normal voltage offset range:
0.97p.u.≤U s 、U Δ 、U v ≤1.07p.u.
(3) Considering constraint conditions of converter during operation, output current constraint of converter station
(4) Considering that the maximum active power transmitted by DC transmission is limited by the maximum DC line current
-U dc I max ≤P s ≤U dc I max
Let the rated apparent power of the VSC at the v point be S vN I.e.
The VSC itself is allowed to run when it is. Area->
Divided into a plurality of tiny blocks, each block being divided into a plurality of tiny blocks by a corresponding power point (P v +jQ v ) The power points satisfying the constraint conditions are obtained by calculating the parameters of all the power points, and the coverage range of the power points is the steady-state operation range section of the converter station.
In actual operation, the steady-state operation range is affected by various factors, and considering that the control strategy of the converter station at the transmitting end is to set the ac side voltage, only the influence of the reference value of the soft dc ac voltage on the steady-state range is considered, and the result of the new energy source transmitting only considering P >0 is shown in fig. 18 and 19.
When the ac voltage increases, the steady-state operating interval of the converter station shifts upward so that the converter station can accept more reactive power capacity.
Definition of a dynamic reactive margin F of a converter station Q In the current new energy output state, namely F Q (P s ,Q s ,U ref )＝min{dQ 1 ,dQ 2 -a }; the shortest distance of the converter station operating point to the upper and lower boundaries is shown in fig. 20.
Ensuring that the converter station has sufficient reactive margin when in steady operation, and feeding the active output in the process of change by changing U ref Maximizing dynamic reactive margin of converter station, i.e. maxF Q . The dynamic reactive margin is changed along with the change of the running state and can not be displayed and expressed by a fixed formula, so that the solution is carried out by adopting a point-by-point heuristic, namely, starting from the current running point, U is continuously changed ref And Q s Calculating until reaching reactive safety feasible region boundary to obtain limit operation point U ref ，Q s Thereby selecting the maximum F Q Time U ref 。
According to the wind field topological structure, calculating the alternating current bus voltage reference value U of the flexible direct current converter station in the wind field operation ref The results are shown in Table 3.
Table 3 ac busbar voltage reference value of the converter station when the reactive margin is guaranteed to be maximum
The total capacity of reactive power required by the large-scale wind power plant which is directly connected into the power grid through the flexibility is closely related to the topology and parameters of the grid connected with the wind power plant, the topology and parameters of the collecting line inside the wind power plant, the fan type, the control strategy of the converter station and the like, so that a reactive power configuration capacity calculation method combining the control strategy of the fan and the control strategy of the converter station is provided, and the detailed calculation flow is as follows:
1) Determining fan type and its control strategy (constant power factor or variable power factor)
2) Establishing an equivalent model inside a wind power plant
3) Determining a set value U of an alternating current bus of a flexible direct-current end converter station ref
4) Judging fan power factor
Selectable range
5) According to reactive shortage Q in the running process of the system q Is provided with corresponding high reactance and SVG
The reactive power sources in the wind farm are wind driven generators, alternating current submarine cables, transformers and converter stations, so that when the reactive power shortage of the system is calculated, the reactive power is obtained according to the current running state, the reactive power shortage is negative, the lack of inductive reactive power is indicated, and the reactive power shortage is positive, the lack of capacitive reactive power is indicated.
Reactive shortage Q q Is Q q ＝-Q WFi -Q C35i -Q C220i +Q Li +Q L35i +Q L220i The method comprises the steps of carrying out a first treatment on the surface of the Wherein Q is WFi Output reactive power for wind power generator, Q C35i 、Q C220i Charging power for AC sea cable, Q Li 、Q L35i 、Q L220i The reactive power loss of the transformer and the AC submarine cable is respectively.
Because the SVG cost is higher than the fixed high-impedance compensation, in order to ensure the minimum investment, the reactive power deficiency fluctuation is ensured to be reduced as far as possible, and the capacity of the dynamic reactive power compensation device is ensured to be minimum, namely, the high-voltage reactor selects the intermediate value of the reactive power deficiency fluctuation range in the wind field operation process:
The investment sum is as follows: m is M i ＝Q 220i *n+Q 35i * m; wherein n is the unit capacity high-resistance cost, and m is the unit capacity SVG cost.
According to the alternating current bus voltage U of the converter station ref Active force P of fan WFi Variable power factor range of fan
The capacity of the reactive power shortage of the system in the process of increasing the active power output can be calculated. When a proper fan power factor is selected to minimize the fluctuation of the reactive power shortage of the system, the capacity of the reactive power compensation equipment required by the steady-state operation of the wind farm can be obtained according to the reactive power shortage of the system, and a specific flow chart is shown in fig. 21.
Taking wind driven generators in two running states as examples, respectively determining power factors (in the active change process, the power factor of a fan is unchanged) and changing the power factors (in the active change process, the power factor of the fan can be changed), and carrying out configuration calculation on reactive equipment of a wind farm:
taking a deep sea wind power cluster as an example, the calculation result and the verification result in a fixed power factor mode are shown in table 4 and table 5 respectively, the calculation result and the verification result in a variable power factor mode are shown in table 6 and table 7 respectively, and the voltage fluctuation in the full power mode and the zero power mode is controlled within 3%. For maximum active fluctuation of a wind farm, SVG can rapidly act (within 5 ms) to meet the requirement.
TABLE 4 configuration of reactive power equipment of deep sea wind power cluster and operation mode of fans
TABLE 5 System Voltage ripple in constant Power factor mode
TABLE 6 configuration of reactive power equipment of deep sea wind power cluster and operation mode of fans
TABLE 7 System Voltage ripple in variable Power factor mode
According to the embodiment, the selection of the alternating current bus voltage reference value in the wind field operation is provided on the premise of ensuring the maximum dynamic reactive margin of the convertor station by quantifying the charging power of the alternating current submarine cable and the reactive control capability of the convertor station; and the capacity of the corresponding reactive compensation device of the wind field is determined by taking the minimum investment as a target according to the fluctuation condition of reactive shortage of the system under the two fan operation methods.
Example two
The second embodiment of the disclosure introduces an offshore wind power reactive compensation optimization computing system based on power factors.
The offshore wind power reactive power compensation optimization calculation method based on the power factors shown in fig. 22 comprises the following steps:
the acquisition module is configured to acquire the fan type and the running state of the offshore wind turbine;
the construction module is configured to construct an offshore wind power equivalent model according to the acquired fan type and the running state;
the judging module is configured to determine the voltage of the alternating current bus of the flexible direct-current end converter station based on the constructed equivalent model; judging the selection range of the fan power factor according to the obtained alternating current bus voltage;
and the calculation module is configured to calculate fluctuation of reactive power shortage of the offshore wind turbine according to the selection range of the power factor of the fan and configure reactive power compensation of the fan.
The detailed steps are the same as those of the offshore wind power reactive power compensation optimization calculation method based on the power factor provided in the first embodiment, and are not described herein again.
Example III
A third embodiment of the present disclosure provides a computer-readable storage medium.
A computer readable storage medium having stored thereon a program which when executed by a processor performs the steps in the power factor based offshore wind power reactive compensation optimization calculation method according to the first embodiment of the present disclosure.
The detailed steps are the same as those of the offshore wind power reactive power compensation optimization calculation method based on the power factor provided in the first embodiment, and are not described herein again.
Example IV
The fourth embodiment of the disclosure provides an electronic device.
An electronic device includes a memory, a processor, and a program stored on the memory and executable on the processor, wherein the processor implements the steps in the power factor-based offshore wind power reactive compensation optimization calculation method according to the first embodiment of the disclosure when executing the program.
The detailed steps are the same as those of the offshore wind power reactive power compensation optimization calculation method based on the power factor provided in the first embodiment, and are not described herein again.
The foregoing description of the preferred embodiments of the present disclosure is provided only and not intended to limit the disclosure so that various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.
While the specific embodiments of the present disclosure have been described above with reference to the drawings, it should be understood that the present disclosure is not limited to the embodiments, and that various modifications and changes can be made by one skilled in the art without inventive effort on the basis of the technical solutions of the present disclosure while remaining within the scope of the present disclosure.
Claims (10)
1. The offshore wind power reactive power compensation optimization calculation method based on the power factor is characterized by comprising the following steps of:
acquiring the fan type and the running state of the offshore wind turbine;
according to the acquired fan type and the running state, constructing an offshore wind power equivalent model;
based on the constructed equivalent model, determining the alternating current bus voltage of the flexible direct-current end converter station;
judging the selection range of the fan power factor according to the obtained alternating current bus voltage;
and calculating fluctuation of reactive power shortage of the offshore wind turbine according to the selection range of the power factors of the fans, and configuring reactive power compensation of the fans.
2. The optimization calculation method for the reactive power compensation of the offshore wind power based on the power factor as claimed in claim 1, wherein the reactive power loss of the offshore wind power is the reactive power loss of a fan-side box-type transformer and an offshore booster station and is related to the active power output by a wind farm; the larger the active power output by the wind farm is, the more reactive power loss of the offshore wind power is.
3. The method for optimizing and calculating the reactive power compensation of the offshore wind power based on the power factor as claimed in claim 1, wherein the control mode of the power supply converter station at the power supply isolated network access flexible-straight time is constant alternating voltage and constant alternating frequency control, and the alternating voltage controlled by the power supply converter station is the busbar voltage at the alternating side; the alternating-current side bus voltage is equivalent to a balance node in the new energy cluster system.
4. The method for optimizing and calculating the reactive power compensation of the offshore wind power based on the power factor as claimed in claim 1, wherein the constraint conditions of the offshore wind power equivalent model comprise the output voltage modulation ratio constraint of the voltage source converter station, the voltage constraint of the common connection point node, the output current constraint of the converter station and the constraint of the maximum direct current line current limit.
5. The optimization calculation method for offshore wind power reactive power compensation based on power factors as claimed in claim 4, wherein the dynamic reactive margin of the converter station is defined as the shortest distance from the operating point of the converter station to the upper and lower boundaries in the current new energy output state; the dynamic reactive margin of the converter station is maximized by changing the alternating current bus when the converter station is in steady state operation.
6. The optimal calculation method for reactive power compensation of offshore wind power based on power factors as claimed in claim 1, wherein the reactive power sources in the wind farm are wind driven generator, alternating current submarine cable, transformer and converter station, and when the reactive power shortage of the offshore wind power generation unit is calculated, according to the current running state of the wind power generation unit, the lack of inductive reactive power is indicated when the reactive power shortage is negative, and the lack of capacitive reactive power is indicated when the reactive power shortage is positive.
7. The optimization calculation method for reactive power compensation of offshore wind power based on power factors as claimed in claim 1, wherein the reactive power deficiency Q of the offshore wind turbine generator is q Is Q q ＝-Q WFi -Q C35i -Q C220i +Q Li +Q L35i +Q L220i The method comprises the steps of carrying out a first treatment on the surface of the Wherein Q is WFi Output reactive power for wind power generator, Q C35i 、Q C220i Charging power for AC sea cable, Q Li 、Q L35i 、Q L220i The reactive power loss of the transformer and the AC submarine cable is respectively.
8. An offshore wind power reactive power compensation optimization computing system based on power factors is characterized by comprising:
the acquisition module is configured to acquire the fan type and the running state of the offshore wind turbine;
the construction module is configured to construct an offshore wind power equivalent model according to the acquired fan type and the running state;
the judging module is configured to determine the voltage of the alternating current bus of the flexible direct-current end converter station based on the constructed equivalent model; judging the selection range of the fan power factor according to the obtained alternating current bus voltage;
and the calculation module is configured to calculate fluctuation of reactive power shortage of the offshore wind turbine according to the selection range of the power factor of the fan and configure reactive power compensation of the fan.
9. A computer readable storage medium having stored thereon a program, which when executed by a processor performs the steps in the power factor based offshore wind power reactive compensation optimization calculation method according to any of claims 1-7.
10. An electronic device comprising a memory, a processor and a program stored on the memory and executable on the processor, wherein the processor performs the steps in the power factor based offshore wind power reactive compensation optimization calculation method of any of claims 1-7 when the program is executed.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116599115A (en) * | 2023-06-13 | 2023-08-15 | 国网江苏省电力有限公司电力科学研究院 | Flexible low-frequency power transmission system optimal operation method, device and equipment based on dynamic voltage adjustment and storage medium |
| CN116646967A (en) * | 2023-05-23 | 2023-08-25 | 华中科技大学 | Transient reactive power optimization method, device and system for onshore grid-following type converter station |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116646967A (en) * | 2023-05-23 | 2023-08-25 | 华中科技大学 | Transient reactive power optimization method, device and system for onshore grid-following type converter station |
| CN116646967B (en) * | 2023-05-23 | 2023-12-22 | 华中科技大学 | Transient reactive power optimization method, device and system for onshore grid-following type converter station |
| CN116599115A (en) * | 2023-06-13 | 2023-08-15 | 国网江苏省电力有限公司电力科学研究院 | Flexible low-frequency power transmission system optimal operation method, device and equipment based on dynamic voltage adjustment and storage medium |
| CN116599115B (en) * | 2023-06-13 | 2024-01-30 | 国网江苏省电力有限公司电力科学研究院 | Flexible low-frequency power transmission system optimal operation method, device and equipment based on dynamic voltage adjustment and storage medium |
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