CN114825419A - Self-adaptive island control system and method for direct current converter station and electronic equipment - Google Patents
Self-adaptive island control system and method for direct current converter station and electronic equipment 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
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
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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
- H02J3/24—Arrangements for preventing or reducing oscillations of 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
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
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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
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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Abstract
The application provides a self-adaptation island control system for flexible direct current converter station connects new forms of energy or passive system, includes: the acquisition conversion unit is used for converting the acquired three-phase voltage and three-phase current on the alternating current side of the flexible direct current converter station into a dq-axis lower voltage signal and a dq-axis lower current signal through an abc/dq coordinate system; the self-adaptive island control unit is automatically switched to control without inner ring current, and the system can be stabilized due to the absence of negative resistance caused by time delay such as sampling control and the like, so that the problem of medium-high frequency oscillation caused by the introduction of negative resistance component due to closed-loop control is avoided, and a more preferable scheme is provided for large-scale new energy access.
Description
Technical Field
The application relates to the technical field of flexible direct current transmission of a power system, in particular to a self-adaptive island control system and method for a direct current converter station and electronic equipment.
Background
In order to solve the problem of global warming caused by the increase of carbon emission, new energy power generation is increasingly paid attention and favored by governments of various countries as a green energy source. Wind power generation, photovoltaic power generation and the like are increasingly valued by various countries as green energy, and new energy including wind power generation and photovoltaic power generation is developed on a large scale in main countries in the world.
The large-scale photovoltaic and wind power resources are generally far away from a load center, the large-scale offshore wind power resources close to the load center need to be transmitted through cables, and how to realize the efficient and high-quality access of large-scale new energy to a power grid is the difficulty of new energy grid connection at present. Although the offshore wind power is close to the load center, the cable is adopted, and when the distance between the wind power plant and the shore exceeds 60km, the difficulties of power loss, land occupation in the sea area, reactive power compensation and the like are gradually increased by adopting a traditional alternating current output mode, so that the alternating current access advantage is reduced.
The flexible direct current transmission is in a flexible control mode, reactive power is not generated by the direct current transmission, and the occupation of land in a small sea area becomes an optional option for large-scale wind power transmission.
When flexible direct current transmission is connected with large-scale new energy, the flexible direct current adopts isolated island control, most of patents and researches concentrate on starting and fault ride-through of new energy access flexible direct current, and the main flow scheme of the existing flexible direct current isolated island control adopts two control strategies of open loop and closed loop: on one hand, the double closed-loop control scheme can effectively suppress fault current, but medium-high frequency oscillation is brought by introducing inner loop current control, and particularly, for example, a double closed-loop control method disclosed in patent CN201610938897 and article, "analysis and control method review of oscillation phenomenon of flexible direct current transmission system" describe analysis of medium-high frequency oscillation phenomenon;
on the other hand, if open-loop control is adopted, such as open-loop control modes proposed in the thesis of black start control capability of the flexible direct-current transmission system and direct voltage control of passive network power supply of the MMC type flexible direct-current transmission system, the open-loop control mode causes current to be uncontrollable and then trip, and is not beneficial to new energy transmission.
The above information disclosed in this background section is only for enhancement of understanding of the background of the application and therefore it may contain information that does not constitute prior art that is already known to a person of ordinary skill in the art.
Disclosure of Invention
The application provides a self-adaptive island control system, a self-adaptive island control method and electronic equipment for a direct current converter station, so that a flexible direct current converter station control system connected with new energy can self-adaptively select a self-adaptive island control method with an inner ring current control mode or without the inner ring current control mode according to the running state of a flexible direct current transmission system, and the self-adaptive island control method can be automatically switched to control without the inner ring current, so that the system is stable because negative resistance caused by time delay such as sampling control does not exist, the problem of medium-high frequency oscillation caused by the introduction of a negative resistance component due to closed-loop control is avoided, the medium-high frequency oscillation risk is avoided, and the controllability of fault current under a fault state is also realized.
According to one aspect of the application, a self-adaptive island control method for a direct current converter station is provided, and comprises the steps of collecting three-phase voltage and three-phase current on an alternating current side of a flexible direct current converter station, and converting the three-phase voltage and the three-phase current into a dq-axis lower voltage signal and a dq-axis lower current signal through an abc/dq coordinate system; and generating a self-adaptive island control bridge arm reference wave by selecting a control mode according to the received voltage setting reference value, frequency setting reference value, the voltage signal and current signal under the dq axis, and the three-phase voltage signal and three-phase current signal on the AC side of the flexible DC converter station.
According to an example embodiment, the selecting the control mode comprises selecting an islanding control mode with in-band loop current control or selecting an islanding control mode without in-band loop current control.
According to the embodiment, the island control mode with the inner-loop current control or the island control mode without the inner-loop current control is selected, including the island control mode under the conditions of starting unlocking and no-load when the system power P is met<Pset1 or Current Peak I peak <Iset1 or
Selecting an island control mode without inner loop current control; otherwise, automatically switching to island mode with in-band loop current, wherein P set1 ≤0.1pu，I set1 ≤0.1pu。
According to an example embodiment, the selecting the island control mode with the in-band loop current control or the selecting the island control mode without the in-band loop current control further includes automatically switching to the island control mode without the in-band loop current control module when the network side voltage harmonic content Us _ h > Us _ hset or the current harmonic content I _ h > Iv _ hset is detected in the control mode of the in-band loop current control module, wherein Us _ hset is greater than or equal to 0.01pu and Iv _ hset is greater than or equal to 0.01 pu.
According to an example embodiment, the selecting the island control mode with inner loop current control or the island control mode without inner loop current control further includes detecting a zero sequence voltage U on the grid side when the control is already under the control of the module without inner loop current control 0 >U 0 Set or grid side current Is>Is _ set or bridge arm current I b >I b When the current value is set, the current value is automatically switched to an in-band ring current control module, wherein the U is 0 _set≥0.05pu，Is_set≥1.15pu，I b _set≥1.15pu。
According to another aspect of the present application, there is provided an adaptive islanding control system for a dc converter station, comprising: the acquisition conversion unit is used for converting the acquired three-phase voltage and three-phase current on the alternating current side of the flexible direct current converter station into a dq-axis lower voltage signal and a dq-axis lower current signal through an abc/dq coordinate system; and the self-adaptive island control unit is used for generating a self-adaptive island control bridge arm reference wave by passing the three-phase voltage signal and the three-phase current signal on the alternating current side of the flexible direct current converter station through the self-adaptive island control unit according to the received voltage setting reference value, the frequency setting reference value, the dq axis lower voltage signal and the current signal.
According to an example embodiment, the adaptive island control unit comprises an island control module with in-band loop current control, and is used for generating a dq-axis closed-loop voltage reference wave; the island control module without inner loop current control is used for generating a dq-axis open-loop voltage reference wave; the frequency phase control module is used for generating synchronous phase signals for the abc/dq coordinate system conversion of the acquisition and conversion unit and the dq/abc coordinate system conversion of the reference wave generation module; the self-adaptive island control selection module is used for selecting an island control module with inner-loop current control or an island control module without inner-loop current control; and the reference wave generation module is used for receiving the synchronous phase signal conversion dq/abc coordinate system of the frequency phase control module and generating six bridge arm reference waves.
According to an example embodiment, the in-band loop current controlled islanding control module includes an output signal that converts the voltage setting reference, the dq-axis down-voltage signal, and the dq-axis down-current signal into a dq-axis closed-loop voltage reference wave.
According to an example embodiment, the island control module without inner loop current control includes an output signal that converts the voltage setting reference and the dq axis lower voltage signal into a dq axis open loop voltage reference wave.
According to an example embodiment, the adaptive islanding control selection module includes an output signal for converting three-phase voltage signals and three-phase current signals on an ac side of the flexible dc converter station, the dq-axis closed-loop voltage reference wave, and the dq-axis open-loop voltage reference wave into an adaptive input reference wave voltage.
According to an example embodiment, the voltage outer loop controller and the current loop controller in both the island control module with inner loop current control and the island control module without inner loop current control comprise a PI controller and/or a PR controller.
According to an aspect of the present application, an electronic device is provided, including: one or more processors; storage means for storing one or more programs; when executed by one or more processors, cause the one or more processors to implement a method as above.
According to the technical scheme, the acquisition and conversion unit is used for converting the acquired three-phase voltage and three-phase current on the alternating current side of the flexible direct current converter station into a dq axis lower voltage signal and a dq axis lower current signal through an abc/dq coordinate system; the self-adaptive island control unit realizes automatic switching to control without inner ring current, can stabilize a system because of no negative resistance caused by time delay such as sampling control and the like, avoids the problem of medium-high frequency oscillation caused by introducing negative resistance components due to closed-loop control, and provides a more preferable scheme for large-scale new energy access.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without exceeding the protection scope of the present application.
Fig. 1a shows a schematic diagram of a flexible dc transmission converter station connection new energy or passive system composition according to an exemplary embodiment of the present application.
Fig. 1b shows a flow chart of an adaptive island control method for connecting a flexible direct current converter station with a new energy source according to an exemplary embodiment of the present application.
Fig. 2 shows a schematic structural diagram of an adaptive island control system for connecting a flexible direct current converter station with new energy according to an embodiment of the application.
Fig. 3 shows a schematic structural diagram of a control unit of an adaptive island control system with a flexible dc converter station connected with a new energy source according to an embodiment of the present application.
Fig. 4 shows an electronic device block diagram of a control device of an adaptive island control system for connecting a flexible direct current converter station with new energy according to an embodiment of the application.
Detailed Description
Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals denote the same or similar parts in the drawings, and thus, a repetitive description thereof will be omitted.
The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the embodiments of the disclosure can be practiced without one or more of the specific details, or with other means, components, materials, devices, etc. In such cases, well-known structures, methods, devices, implementation steps, materials, or operations are not shown or described in detail.
Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.
The terms "first," "second," and the like in the description and claims of the present application and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions.
Fig. 1a shows a schematic diagram of a flexible dc transmission converter station connected to a new energy source or a passive system according to an exemplary embodiment of the present application, taking connection of a large wind farm as an example.
As shown in fig. 1a, according to an embodiment, a flexible dc transmission converter station-connected offshore wind power new energy system 1000 generally includes an ac booster station 1001, an offshore flexible dc transmission converter station 2001 (hereinafter referred to as an offshore converter station), and an onshore converter station 3001. Electric energy generated by an offshore wind farm is boosted by the alternating current booster station 1001 and then is connected to the offshore converter station 2001. Direct current is output through an offshore converter station 2001 and is connected to an onshore converter station 3001 through a submarine cable 4000, so that power of the wind power plant is transmitted to an onshore alternating current power grid 5000 from the sea.
With continued reference to fig. 1a, the offshore converter station 2001 generally comprises: ac busbar 2100, station transformer 2200, junction transformer 2300, valve-side busbar 2400, valve-side switch (not shown), converter valve and dc field device 2600 and corresponding measurement or control devices. The converter valves and dc field devices 2600 typically include converter valves, bridge arm reactors, dc field devices, and the like.
According to an embodiment, during power transmission, wind power generated by an offshore wind farm is boosted and then connected to the ac bus 2100 of the offshore converter station 2001. The ac busbar 2100 is connected to the valve-side busbar 2400 by two parallel sets of coupling transformers 2300. Valve side bus 2400 is connected to the ac side of converter valve and dc field device 2600. The marine converter station 2001 supplies power to other equipment of the marine converter station through the high voltage station power transformer 2200. In the whole control process, the offshore converter station generates stable alternating current voltage through island control to supply new offshore wind power energy to be connected to the grid.
Fig. 1b shows a flow chart of an adaptive island control method for connecting a flexible direct current converter station with a new energy source according to an exemplary embodiment of the present application.
Referring to fig. 1b, according to an embodiment, at S101, three-phase voltages and three-phase currents on the ac side of the flexible dc converter station are collected and converted into a dq-axis voltage signal and a dq-axis current signal through an abc/dq coordinate system.
In S103, a self-adaptive island control bridge arm reference wave is generated by selecting a control mode according to a received voltage setting reference value, a frequency setting reference value, the voltage signal and the current signal under the dq axis, and the three-phase voltage signal and the three-phase current signal on the AC side of the flexible DC converter station.
According to an embodiment, the control mode is selected, including selecting an island control mode with inner loop current control or selecting an island control mode without inner loop current control, and the specific switching process of the two modes will be described in detail with reference to fig. 3.
Fig. 2 shows a schematic structural diagram of an adaptive island control system for connecting a flexible dc converter station with a new energy source according to a first exemplary embodiment of the present application.
As shown in fig. 1b and fig. 2, according to an example embodiment, the adaptive island control method for a flexible direct current transmission converter station provided by the present application includes:
and S101, three-phase voltage and three-phase current on the alternating current side of the flexible direct current converter station are collected and converted into a voltage signal under a dq axis and a current signal under the dq axis through an abc/dq coordinate system.
And S103, generating a self-adaptive island control bridge arm reference wave by selecting a control mode according to the received voltage setting reference value, the frequency setting reference value, the voltage signal and the current signal under the dq axis, the three-phase voltage signal and the three-phase current signal reflecting the flexible and direct running state.
According to an embodiment, the control mode is selected, comprising selecting an island control mode with inner loop current control or selecting an island control mode without inner loop current control. An embodiment of selecting the control mode as described above will be described later with reference to fig. 3. The specific structure of the control system will be described below with reference to fig. 2.
Referring to fig. 2, the adaptive islanding control system for the flexible direct current transmission converter station includes an acquisition conversion unit 100 and an adaptive islanding control unit 200.
The acquisition conversion unit 100 is used for converting the acquired three-phase voltage and three-phase current on the alternating current side of the flexible direct current converter station into a dq-axis lower voltage signal and a dq-axis lower current signal through an abc/dq coordinate system.
The adaptive island control unit 200 is configured to generate an adaptive island control bridge arm reference wave by passing a three-phase voltage signal and a three-phase current signal which reflect a soft and direct operation state through the adaptive island control unit according to a received voltage setting reference value, a dq-axis lower voltage signal and a received current signal.
According to an embodiment, the acquisition conversion unit 100 comprises a first input 101, a second input 102, a third input 103, a first output 111, a second output 112.
The first input terminal 101 is used for receiving three-phase voltage signals at the ac side of the flexible dc converter station.
The second input terminal 102 is configured to receive three-phase current signals at the ac side of the flexible dc converter station.
The third input 103 is for receiving a synchronized phase angle signal.
The first output 111 is used for outputting a voltage signal reflecting the flexible dc operating state.
The second output terminal 112 is used for outputting a current signal reflecting the flexible direct current operation state.
According to an embodiment, the adaptive island control unit 102 includes a first input 201, a second input 202, a third input 203, a fourth input 204, a fifth input 211, a sixth input 212, a first output 261, a second output 262, a third output 263, a fourth output 264, a fifth output 265, a sixth output 266, and a seventh output 267.
The first input terminal 201 is used for receiving a voltage setting reference value.
The second input terminal 202 is used for generating a synchronized phase angle signal to the third input terminal of the acquisition and conversion unit and generating a reference wave by itself.
The third input terminal 203 is used for receiving a voltage signal reflecting the flexible dc operating state.
The fourth input 204 is for receiving a current signal reflecting the soft dc operating condition.
The fifth input terminal 211 is for receiving a dq-axis voltage signal.
The sixth input 212 is for receiving a dq-axis down current signal.
The first output end 261, the second output end 262, the third output end 263, the fourth output end 264, the fifth output end 265 and the sixth output end 266 respectively output three-phase upper bridge arm reference waves and three-phase lower bridge arm reference waves of the adaptive island control unit.
The seventh output 267 is configured to output the synchronized phase angle signal.
According to an embodiment, referring to fig. 2, the first output 111 of the acquisition and conversion unit is connected to the fifth input 211 of the adaptive island control unit, the second output 112 of the acquisition and conversion unit is connected to the sixth input 212 of the adaptive island control unit, and the seventh output 267 of the adaptive island control unit is connected to the third input 103 of the acquisition and conversion unit.
The acquisition conversion unit 100 is used for converting the acquired flexible direct current alternating current side three-phase voltage and three-phase current into dq axis lower voltage Udq and current Idq through abc/dq according to the received potential angle signal, and the flexible direct current alternating current side three-phase voltage and three-phase current reach the acquisition conversion unit 100 through a first input end 101 and a second input end 102 of the acquisition conversion unit respectively; the third input terminal 103 of the acquisition and conversion unit 100 acquires the phase angle signal fed by the seventh output terminal 267 of the adaptive island control unit 200.
According to the embodiment, optionally, the first output terminal 101 and the second output terminal 102 of the acquisition conversion unit 100 can be combined into one output terminal to be sent to the adaptive island control unit 200, and accordingly, the fifth input terminal 211 and the sixth input terminal 212 of the adaptive island control unit 200 can be combined into one input terminal to receive the signal output by the acquisition conversion unit 100.
Alternatively, the third input terminal 203 and the fourth input terminal 204 of the adaptive island control unit 200 can also be combined to the fifth input terminal 211 and the sixth input terminal 212, the third input terminal 203 and the fourth input terminal 204 are omitted, and the three-phase voltage signals and the three-phase current signals output by the first output terminal 101 and the second output terminal 102 of the acquisition unit 100 are directly sent to the fifth input terminal 211 and the sixth input terminal 212 of the adaptive island control unit 200.
The adaptive island control unit 200 is configured to set a reference value according to the received voltage
And the voltage Udq and the current Idq under the dq axis are subjected to adaptive island control according to the three-phase voltage and the current reflecting the flexible and direct running state to generate an adaptive island control bridge arm reference wave. The adaptive island control unit 200 generates a phase angle signal θ according to the received frequency setting reference value f _ ref to the acquisition and conversion unit 100 and generates a reference wave for use. Voltage of (2) setting reference value
The frequency setting reference value f _ ref, the dq axis voltage Udq and the dq axis current Idq are respectively sent to the adaptive island control unit 200 through a first input terminal 201, a second input terminal 202, a fifth input terminal 211 and a sixth input terminal 212 of the adaptive control unit; three-phase voltage and three-phase current signals reflecting the flexible direct current running state are respectively sent to the adaptive island control 200 through a third input end 203 and a fourth input end 204 of the adaptive control unit, a first output end 261, a second output end 262, a third output end 263, a fourth output end 264, a fifth output end 265 and a sixth output end 266 of the island control unit respectively output flexible direct current three-phase upper bridge arm and three-phase lower bridge arm reference waves to be transmitted to the flexible direct current valve control system (not shown), and a seventh output end 267 of the island control unit outputs a phase angle signal theta to the third input end 103 of the acquisition and conversion unit.
Fig. 3 shows a schematic structural diagram of an adaptive island control unit 200 of an adaptive island control system with a flexible dc converter station connected to a new energy source according to an embodiment of the present application.
As shown in fig. 3, according to an example embodiment, the adaptive island control unit 200 of the flexible direct current transmission converter station provided by the present application includes an island control module 210 with inner loop current control, an island control module 220 without inner loop current control, a frequency phase control module 230, an adaptive island control selection module 240, and a reference wave generation module 250.
An island control module 210 with inner loop current control is used to generate a dq axis closed loop voltage reference wave.
The island control module 220 without inner loop current control is used to generate a dq axis open loop voltage reference wave.
The frequency phase control module 230 is used for generating a synchronous phase signal for the abc/dq coordinate system conversion of the acquisition and conversion unit and the dq/abc coordinate system conversion of the reference wave generation module.
The adaptive island control selection module 240 is used to select an island control module with in-band loop current control or an island control module without inner loop current control.
The reference wave generating module 250 is used for receiving the synchronous phase signal conversion dq/abc coordinate system of the frequency phase control module and generating six bridge arm reference waves.
According to an embodiment, the in-band loop current controlled island control module 210 comprises a first input 213, a second input 214, a third output 215 and a first output 217.
The first input terminal 213 is used for receiving a voltage setting reference value.
The second input terminal 214 is for receiving a dq-axis voltage signal.
The third input terminal 215 is for receiving a dq-axis down current signal.
The first output terminal 217 is used for outputting a dq-axis closed-loop voltage reference wave.
According to an embodiment, the island control module without inner loop current control 220 includes a first input 221, a second input 222, and a first output 226.
The first input terminal 221 is used for receiving a voltage setting reference value.
A second input terminal 222 for receiving the dq-axis voltage signal.
A first output terminal 226 for outputting a dq-axis open-loop voltage reference wave.
According to an embodiment, the adaptive island control selection module comprises a first input 241, a second input 242, a third input 243, a fourth input 244 and a first output 246.
The first input 241 is for receiving a voltage signal reflecting a soft dc operating condition.
The second input 242 is for receiving a current signal reflecting the soft dc operating condition.
The third input 243 is for receiving a dq-axis closed-loop voltage reference wave.
The fourth input 244 is for receiving a dq axis open loop voltage reference wave.
The first output 246 is used for outputting the adaptive input reference wave voltage.
According to an embodiment, the first output 217 of the in-band loop current controlled island control module 210 is connected to the third input 243 of the adaptive island control selection module 240; the first output 226 of the island control module 220 without inner loop current control is connected to the fourth input 244 of the adaptive island control selection module 240; the output end 232 of the frequency phase control module 230 is connected with the second input end 252 of the reference wave generation module; the first output 246 of the adaptive island control selection module 240 is connected to the first input 251 of the reference wave generation module.
According to an embodiment, the islanding control module 210 with in-band loop current control is configured to set a reference value according to a received voltage
And the dq axis voltage Udq generates a current reference wave Idq _ ref through the outer ring voltage controller, and the current reference wave Idq _ ref and the dq axis current Idq generate a dq axis closed-loop voltage reference wave Udq _ ref _ cl with current closed-loop control through the inner ring current controller and are sent to a third input end 243 of the self-adaptive island control selection module; wherein the voltage sets the reference value
The dq axis voltage Udq and the dq axis current Idq are fed into a first input end 213, a second input end 214 and a third input end of an island control module with the function of controlling the in-band loop currentAn input terminal 215.
According to an embodiment, the islanding control module 220 without inner loop current control is used for setting a reference value according to the received voltage
And dq axis voltage Udq is controlled by an outer ring voltage to generate a dq axis open-loop voltage reference wave Udq _ ref _ op without current closed-loop control, and the dq axis voltage reference wave Udq is sent to a fourth input end 244 of the self-adaptive island control selection module 240; wherein the voltage sets the reference value
And the dq axis voltage Udq is fed to the first input 221 and the second input 222 of the island control module without inner loop current control.
The frequency phase control module 230 is used for generating a synchronous phase signal according to the received frequency setting reference value f _ ref for the acquisition and conversion module abc/dq conversion and the reference wave generation module dq/abc conversion. The frequency setting reference f _ ref is coupled to the frequency phase control module first input 231. The first output 232 of the frequency phase control module is connected to the third input 252 of the reference wave generating module.
The adaptive island control selection module 240 is configured to adaptively select a dq axis closed-loop voltage reference wave Udq _ ref _ cl with current closed-loop control or a dq axis open-loop voltage reference wave Udq _ ref _ op without current closed-loop control according to a flexible direct current operation state, where the flexible direct current operation state is adaptively determined and selected by three-phase voltage and three-phase current or a three-phase voltage and three-phase current comprehensive quantity. The flexible direct current operation state is connected to the first input end 241 and the second input end 242 of the self-adaptive island control selection module through three-phase voltage and three-phase current. A dq-axis closed-loop voltage reference wave Udq _ ref _ cl with current closed-loop control or a dq-axis open-loop voltage reference wave Udq _ ref _ op without current closed-loop control is respectively sent to the third input end 243 and the fourth input end 244 of the adaptive island control selection module. The adaptive input reference wave selected after the adaptive decision based on the soft-straight running state is sent to the output 246 of the adaptive island control selection module.
The reference wave generation module 250 is configured to convert dq voltage reference waves output by the adaptive island control selection module and synchronous phase signals controlled by frequency phases into abc coordinates through dq/abc and then generate six bridge arm reference waves required by valve control. The output dq axis reference voltage of the adaptive island control selection module is sent to a first input end 251 of a reference wave generation module, and the generated six bridge arm reference waves are respectively sent to a first output end 254 to a sixth output end 259 of the reference wave generation module.
The selection criterion for adaptively judging the soft and direct running state adaptive selection module to select the dq axis closed-loop voltage reference wave Udq _ ref _ cl with current closed-loop control or the dq axis open-loop voltage reference wave Udq _ ref _ op with no current closed-loop control according to the three-phase voltage, the three-phase current or the active power is as follows:
according to the embodiment, when the system power P is satisfied under the conditions of flexible direct current starting unlocking and no-load state<Pset1 or Current Peak Ipeak<Iset1 or
If not, the island control module 220 without inner loop current control is selected to operate, otherwise, the island control module 210 with inner loop current is automatically switched to, and another Pset1 is less than or equal to 0.1pu, and Iset1 is less than or equal to 0.1 pu.
Under the control of the in-band loop current control module 210, when the voltage harmonic content Us _ h > Us _ hset or the current harmonic content I _ h > Iv _ hset of the flexible direct system is detected, the system is automatically switched to an island control system without an inner loop current control module, wherein Us _ hset is greater than or equal to 0.01pu, and Iv _ hset is greater than or equal to 0.01 pu.
Under the control of the control module without the inner loop current, when the zero sequence voltage U0 of the network side current Is > U0_ set, the network side current Is > Is _ set or the bridge arm current Ib > Ib _ set Is detected, the control module Is automatically switched to the control module with the inner loop current, U0_ se t Is more than or equal to 0.05pu, Is _ set Is more than or equal to 1.15pu, and Ib _ set Is more than or equal to 1.15 pu.
The above-mentioned dq-axis voltage Udq, the dq-axis current Idq,
The instruction value, Udq _ ref _ cl, Udq _ ref _ op, represents the positive and negative sequence components for a total of four components.
After receiving the dq-axis adaptive input reference wave and the synchronous phase angle signal, the input ends 251 and 252 of the reference wave generation module 250 respectively generate three-phase voltages Ux _ ref (a, b, c) for positive and negative sequence superposition after dq/abc conversion, and then generate six bridge arm reference waves respectively through signal conversion Vxu _ ref ═ Udc/2-Ux _ ref (x ═ a, b, c) and Vx _ dref ═ Udc/2-Ux _ ref, where Udc sets a reference value for a direct current voltage.
The voltage outer ring control and current ring controller in the island control module with inner ring current control and the island control module without inner ring current control can be a PI controller or a PR controller.
Fig. 4 shows an electronic device block diagram of an adaptive island control device of an adaptive island control system in which a flexible direct current converter station is connected with new energy according to an embodiment of the application.
As shown in fig. 4, electronic device 400 is embodied in the form of a general purpose computing device. The components of electronic device 400 may include, but are not limited to: at least one processing unit 410, at least one memory unit 420, a bus 430 that connects the various system components (including the memory unit 420 and the processing unit 410), a display unit 440, and the like.
Wherein the storage unit stores program code, which can be executed by the processing unit 410, to cause the processing unit 410 to perform the methods according to various exemplary embodiments of the present application described herein.
The electronic device 400 may also communicate with one or more external devices 500 (e.g., keyboard, pointing device, bluetooth device, etc.), with one or more devices that enable a user to interact with the electronic device 400, and/or with any devices (e.g., router, modem, etc.) that enable the electronic device 400 to communicate with one or more other computing devices. Such communication may occur via input/output (I/O) interfaces 450. Also, the electronic device 400 may communicate with one or more networks (e.g., a Local Area Network (LAN), a Wide Area Network (WAN), and/or a public network, such as the internet) via the network adapter 460. The network adapter 460 may communicate with other modules of the electronic device 400 via the bus 430. It should be appreciated that although not shown in the figures, other hardware and/or software modules may be used in conjunction with electronic device 400, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, among others.
According to the self-adaptive island control system, the self-adaptive island control method and the electronic equipment for the direct current converter station, the self-adaptive island control method with an inner loop current control mode or without the inner loop current control mode is selected by the control system of the direct current converter station connected with new energy in a self-adaptive mode according to the running state of a flexible direct current transmission system, and the system can be stabilized by automatically switching to the control without the inner loop current because of the absence of negative resistance caused by time delay such as sampling control and the like, so that the problem of medium-high frequency oscillation caused by the introduction of negative resistance components due to closed-loop control is avoided, the medium-high frequency oscillation risk is avoided, and the controllability of fault current in a fault state is also realized.
The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application, and the description of the embodiments is only intended to facilitate the understanding of the methods and their core concepts of the present application. Meanwhile, a person skilled in the art should, according to the idea of the present application, change or modify the embodiments and applications of the present application based on the scope of the present application. In view of the above, the description should not be taken as limiting the application.
Claims (12)
1. An adaptive island control method for a direct current converter station, characterized by comprising:
acquiring three-phase voltage and three-phase current on the alternating current side of the flexible direct current converter station, and converting the three-phase voltage and the three-phase current into a dq-axis lower voltage signal and a dq-axis lower current signal through an abc/dq coordinate system;
and generating a self-adaptive island control bridge arm reference wave by selecting a control mode according to the received voltage setting reference value, frequency setting reference value, the voltage signal and current signal under the dq axis, and the three-phase voltage signal and three-phase current signal on the AC side of the flexible DC converter station.
2. The method of claim 1, wherein selecting the control mode comprises:
and selecting an island control mode with inner loop current control or selecting an island control mode without inner loop current control.
3. The method of claim 2, wherein selecting either an island control mode with in-band loop current control or an island control mode without in-band loop current control comprises:
when the system power P is satisfied in the starting unlocking and no-load state<Pset1 or Current Peak I peak <Iset1 or
Selecting an island control mode without inner loop current control;
otherwise it will automatically switch to island mode with in-band loop current,
wherein, the P set1 ≤0.1pu，I set1 ≤0.1pu。
4. The method of claim 2, wherein selecting either an island control mode with in-band loop current control or an island control mode without in-loop current control further comprises:
when the network side voltage harmonic content Us _ h > Us _ hset or the current harmonic content I _ h > Iv _ hset is detected in the control mode of the in-band loop current control module, the island control mode without the in-band loop current control module is automatically switched to,
wherein, the Us _ hset is more than or equal to 0.01pu, and the Iv _ hset is more than or equal to 0.01 pu.
5. The method of claim 2, wherein selecting either an island control mode with in-band loop current control or an island control mode without inner loop current control further comprises:
under the control of a control module without an inner loop current, when the zero sequence voltage U on the network side is detected 0 >U 0 Set or grid side current Is>Is _ set or bridge arm current I b >I b When _ set is detected, the control module is automatically switched to the control module of the in-band ring current control,
wherein, the U 0 _set≥0.05pu，Is_set≥1.15pu，I b _set≥1.15pu。
6. An adaptive island control system for a direct current converter station, comprising:
the acquisition conversion unit is used for converting the acquired three-phase voltage and three-phase current on the alternating current side of the flexible direct current converter station into a dq-axis lower voltage signal and a dq-axis lower current signal through an abc/dq coordinate system;
and the self-adaptive island control unit is used for generating a self-adaptive island control bridge arm reference wave by passing the three-phase voltage signal and the three-phase current signal on the alternating current side of the flexible direct current converter station through the self-adaptive island control unit according to the received voltage setting reference value, the frequency setting reference value, the dq axis lower voltage signal and the current signal.
7. The system of claim 6, wherein the adaptive islanding control unit comprises:
the island control module with the inner loop current control is used for generating a dq-axis closed-loop voltage reference wave;
the island control module without inner loop current control is used for generating a dq-axis open-loop voltage reference wave;
the frequency phase control module is used for generating synchronous phase signals for the abc/dq coordinate system conversion of the acquisition and conversion unit and the dq/abc coordinate system conversion of the reference wave generation module;
the self-adaptive island control selection module is used for selecting an island control module with inner-loop current control or an island control module without inner-loop current control;
and the reference wave generation module is used for receiving the synchronous phase signal conversion dq/abc coordinate system of the frequency phase control module and generating six bridge arm reference waves.
8. The system of claim 7, wherein the in-band loop current controlled islanding control module comprises:
and converting the voltage setting reference value, the dq-axis lower voltage signal and the dq-axis lower current signal into an output signal of a dq-axis closed-loop voltage reference wave.
9. The system of claim 7, wherein the islanding control module without inner loop current control comprises:
and converting the voltage setting reference value and the dq-axis lower voltage signal into an output signal of a dq-axis open-loop voltage reference wave.
10. The system according to any of claims 7 to 9, wherein the adaptive islanding control selection module comprises:
and converting the three-phase voltage signals and the three-phase current signals at the AC side of the flexible DC converter station, the dq axis closed-loop voltage reference waves and the dq axis open-loop voltage reference waves into output signals of self-adaptive input reference wave voltages.
11. The system of claim 6, wherein voltage outer loop controllers and current loop controllers in both the in-band inner loop current controlled island control module and the non-inner loop current controlled island control module comprise PI controllers and/or PR controllers.
12. An electronic device, comprising:
one or more processors;
storage means for storing one or more programs;
when executed by the one or more processors, cause the one or more processors to implement the method of any one of claims 1-13.
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| CN202110071233.0A CN114825419B (en) | 2021-01-19 | 2021-01-19 | Self-adaptive island control system and method for direct-current converter station and electronic equipment |
| MX2023007693A MX2023007693A (en) | 2021-01-19 | 2022-01-18 | Control method and system for island operation of vsc-hvdc system. |
| PCT/CN2022/072571 WO2022156681A1 (en) | 2021-01-19 | 2022-01-18 | Control method and system for island operation of vsc-hvdc system |
| EP22742160.9A EP4283816A1 (en) | 2021-01-19 | 2022-01-18 | Control method and system for island operation of vsc-hvdc system |
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