CN112636379A - Virtual control method and system for direct current - Google Patents
Virtual control method and system for direct current Download PDFInfo
- Publication number
- CN112636379A CN112636379A CN202011449372.4A CN202011449372A CN112636379A CN 112636379 A CN112636379 A CN 112636379A CN 202011449372 A CN202011449372 A CN 202011449372A CN 112636379 A CN112636379 A CN 112636379A
- Authority
- CN
- China
- Prior art keywords
- direct current
- current
- control
- virtual
- trend
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 22
- 230000008859 change Effects 0.000 claims abstract description 29
- 238000011084 recovery Methods 0.000 claims abstract description 13
- 230000000694 effects Effects 0.000 claims abstract description 7
- 238000005259 measurement Methods 0.000 claims description 10
- 230000005540 biological transmission Effects 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 11
- 238000004590 computer program Methods 0.000 description 7
- 230000006870 function Effects 0.000 description 4
- 238000003860 storage Methods 0.000 description 3
- 238000009499 grossing Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 230000001174 ascending effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000004393 prognosis Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
Images
Classifications
-
- 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
-
- 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]
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Rectifiers (AREA)
Abstract
The invention relates to a virtual control method and a virtual control system for direct current, wherein the virtual control method comprises the following steps: predicting the change trend of the direct current; in the initial stage of fault development and the initial stage of direct current change, generating virtual current with an increased change trend for direct current control, and accelerating the control speed of the direct current; the control effect becomes effective, and after the direct current is restrained, virtual current with reduced variation trend is generated for controlling the direct current, so that the control speed of the direct current is slowed down, and overshoot is restrained; in the recovery stage of the direct current, the virtual current with the reduced variation trend is adopted for controlling the direct current, so that the control speed of the direct current is accelerated, and the direct current is recovered to the instruction value as soon as possible. The invention optimizes the control performance of the DC controller, overcomes the problems of control lag and overshoot caused by the inertia of the DC system, reduces the influence of DC disturbance on the AC system, and enhances the stability of the AC/DC system.
Description
Technical Field
The invention relates to the field of extra-high voltage direct current engineering, in particular to a virtual control method and a virtual control system for direct current.
Background
In the traditional extra-high voltage direct current project using a thyristor as a converter element, a rectification side controls direct current, and an inversion side controls direct voltage or adopts prediction type arc extinguishing angle control. The main link for realizing current closed-loop control in the current extra-high voltage direct current engineering is a proportional-integral (PI) controller, which performs proportional-integral control on a difference value of an actually measured direct current and a current instruction and outputs a trigger angle to realize the adjustment of the direct current. The current controller has the characteristics of quick and accurate adjustment, can quickly respond and control fault current in case of fault, and can keep zero-error adjustment of the current in a steady state. The direct-current power transmission system comprises main equipment such as a converter transformer, a converter valve, a smoothing reactor, a direct-current circuit, an alternating-current and direct-current filter and the like, and the whole power transmission loop has a large inertia effect. The control system acts on a direct current system with inertia, and the control system has the inevitable problems of control lag and overshoot. When a direct current system is greatly disturbed, for example, when phase change failure occurs, direct current can rapidly rise, due to control lag and overshoot, direct current can rapidly rise firstly, then greatly fall or even reach zero, reactive power consumed by a converter can also be high firstly and low secondly, and then the voltage of a converter bus can successively experience low voltage and overvoltage, so that the alternating current system is influenced.
The problems of control lag and overshoot caused by the inertia of a direct current system influence the stable operation of an alternating current and direct current system, in recent years, the influence is weakened by additionally arranging dynamic reactive power compensation devices such as a phase modifier, SVC (static var compensator), SVG (static var compensator) and the like in extra-high voltage direct current supporting engineering, the prognosis effect of the compensation mode is limited by technology or equipment, and in addition, the engineering investment is increased. In consideration of the problems, the strategy of the direct current controller is improved, control lag and overshoot caused by inertia of a direct current system are overcome, the control performance of the direct current system during disturbance is optimized, and the method has important significance for strengthening the stability of the alternating current and direct current system.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a virtual control method and system for dc current, which generates a virtual dc current for control by predicting a variation trend of the dc current, so as to optimize the control performance of a dc current controller.
In order to achieve the purpose, the invention adopts the following technical scheme: a virtual control method of direct current is realized based on the existing direct current transmission system, after the direct current is subjected to virtualization processing, a difference value between the direct current and a current instruction is sent to a proportional-integral controller, a trigger angle is output, and the control of the direct current is realized.
Further, the virtual control method of the direct current comprises the following steps: 1) predicting the change trend of the direct current; 2) in the initial stage of fault development and the initial stage of direct current change, generating virtual current with an increasing change trend, and superposing the virtual current on an actual direct current measurement value for direct current control to accelerate the control speed of the direct current; 3) the control effect becomes effective, and after the direct current is restrained, virtual current with reduced variation trend is generated and is superposed on an actual direct current measurement value for direct current control, the control speed of the direct current is slowed down, and overshoot is restrained; 4) in the recovery stage of the direct current, the virtual current with the reduced variation trend is adopted for controlling the direct current, so that the control speed of the direct current is accelerated, and the direct current is recovered to the instruction value as soon as possible.
Further, in step 2), the actual dc current is in an increasing trend, and the actual dc current at the current time is subtracted from the actual dc current at the previous time to generate a virtual current with an increasing trend.
Further, in the step 3), the actual direct current is in a downward trend, and the actual direct current at the current moment is subtracted from the actual direct current at the previous moment to generate a virtual current with a reduced variation trend.
A virtual control system for direct current, comprising: the device comprises a prediction module, a first control module, a second control module and a recovery module; the prediction module is used for predicting the change trend of the direct current; the first control module generates virtual current with an increasing change trend at the initial stage of fault development and the initial stage of direct current change, and the virtual current is superposed on an actual direct current measurement value and used for direct current control to accelerate the control speed of the direct current; the second control module generates virtual current with reduced variation trend after the control action is effective and the direct current is restrained, and the virtual current is superposed on an actual direct current measurement value and used for direct current control, so that the control speed of the direct current is slowed down, and overshoot is restrained; the recovery module adopts the virtual current with the reduced variation trend for the direct current control in the recovery stage of the direct current, so that the control speed of the direct current is accelerated, and the direct current is recovered to the instruction value as soon as possible.
Further, in the first control module, the actual direct current is in an ascending trend, and the actual direct current at the current moment is subtracted from the actual direct current at the previous moment to generate a virtual current increasing the change trend.
Further, in the second control module, the actual direct current is in a descending trend, and the actual direct current at the current moment is subtracted from the actual direct current at the previous moment to generate a virtual current for reducing the change trend.
Due to the adoption of the technical scheme, the invention has the following advantages: 1. in the initial stage of the fault, the invention accelerates the regulation speed of the DC controller, overcomes the problem of control system lag caused by the inertia of the DC system, and is beneficial to the inhibition of the fault current. 2. After the control action of the invention is effective, the control speed of the direct current is slowed down, and the problem of control overshoot is restrained. 3. The invention optimizes the control performance of the DC controller, overcomes the problems of control lag and overshoot caused by the inertia of the DC system, reduces the influence of DC disturbance on the AC system, and enhances the stability of the AC/DC system. The method can be widely applied to the current control strategy of the extra-high voltage direct current engineering.
Drawings
FIG. 1 is a logic block diagram of a virtual DC current control method according to the present invention.
Fig. 2 is a schematic diagram of a dc power transmission system.
Fig. 3 is a logic block diagram of a typical dc current controller.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.
In the prior art, a current controller logic as shown in fig. 3 is generally adopted in an extra-high voltage dc project, and a difference value between an actually measured dc current (ID) and a current Instruction (IORD) is sent to a proportional-integral (PI) controller to output a trigger angle, so as to realize control of the dc current.
In order to optimize the control performance of the direct current and overcome the problems of control lag and overshoot caused by the inertia of a direct current system, the invention provides a virtual control method of the direct current, which is realized based on the existing direct current transmission system as shown in fig. 1.
As shown in fig. 2, the conventional dc power transmission system includes main devices such as a converter transformer 1, a converter valve 2, a smoothing reactor 3, a dc line 4, a dc filter 5, and an ac filter 6, and the entire power transmission circuit has a large inertia effect. The control system acts on a direct current system with inertia, and the control system has the inevitable problems of control lag and overshoot.
In a preferred embodiment, the virtual control method of the direct current of the invention comprises the following steps:
1) predicting the change trend of the direct current;
2) at the initial stage of fault development and the initial stage of direct current change, actual direct current is in a rising trend, the actual direct current at the current moment is subtracted from the actual direct current at the previous moment to generate virtual current with the increased change trend, and the virtual current is superposed on the actual direct current measured value and used for direct current control to accelerate the control speed of the direct current;
3) the control effect becomes effective, after the direct current is restrained, the actual direct current is in a descending trend, the actual direct current at the current moment is subtracted from the actual direct current at the previous moment to generate a virtual current with a reduced change trend, the virtual current is superposed on the actual direct current measured value and used for direct current control, the control speed of the direct current is slowed down, and the overshoot is restrained;
4) in the recovery stage of the direct current, the virtual current with the reduced variation trend is adopted for controlling the direct current, so that the control speed of the direct current is accelerated, and the direct current is recovered to the instruction value as soon as possible.
The present invention also provides a virtual control system for dc current, which includes: the device comprises a prediction module, a first control module, a second control module and a recovery module;
the prediction module is used for predicting the change trend of the direct current;
the first control module generates virtual current with an increasing change trend at the initial stage of fault development and the initial stage of direct current change, and the virtual current is superposed on an actual direct current measurement value and used for direct current control to accelerate the control speed of the direct current;
the second control module generates virtual current with reduced variation trend after the control action is effective and the direct current is restrained, and the virtual current is superposed on the actual direct current measurement value and used for direct current control, so that the control speed of the direct current is slowed down, and the overshoot is restrained;
and the recovery module adopts the virtual current with the reduced variation trend for the direct current control in the recovery stage of the direct current, so that the control speed of the direct current is accelerated, and the direct current is recovered to the instruction value as soon as possible.
In the above embodiment, in the first control module, the actual direct current is in an increasing trend, and the actual direct current at the current time is subtracted from the actual direct current at the previous time to generate a virtual current with an increasing trend.
In the above embodiment, in the second control module, the actual direct current is in a downward trend, and the actual direct current at the current time is subtracted from the actual direct current at the previous time to generate a virtual current with a reduced variation trend.
In conclusion, the invention optimizes the control performance of the direct current controller, overcomes the problems of control lag and overshoot caused by the inertia of the direct current system, reduces the influence of direct current disturbance on the alternating current system, and enhances the stability of the alternating current and direct current systems.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Claims (7)
1. A virtual control method of direct current is characterized in that the method is realized based on the existing direct current transmission system, after the direct current is subjected to virtualization processing, a difference value between the direct current and a current instruction is sent to a proportional-integral controller, a trigger angle is output, and the control of the direct current is realized.
2. The control method according to claim 1, wherein the virtual control method of the direct current comprises the steps of:
1) predicting the change trend of the direct current;
2) in the initial stage of fault development and the initial stage of direct current change, generating virtual current with an increasing change trend, and superposing the virtual current on an actual direct current measurement value for direct current control to accelerate the control speed of the direct current;
3) the control effect becomes effective, and after the direct current is restrained, virtual current with reduced variation trend is generated and is superposed on an actual direct current measurement value for direct current control, the control speed of the direct current is slowed down, and overshoot is restrained;
4) in the recovery stage of the direct current, the virtual current with the reduced variation trend is adopted for controlling the direct current, so that the control speed of the direct current is accelerated, and the direct current is recovered to the instruction value as soon as possible.
3. The control method according to claim 2, wherein in the step 2), the actual direct current is in an increasing trend, and the actual direct current at the current time is subtracted from the actual direct current at the previous time to generate a virtual current with an increasing trend of change.
4. The control method according to claim 2, wherein in the step 3), the actual direct current is in a downward trend, and the actual direct current at the current time is subtracted from the actual direct current at the previous time to generate a virtual current with a reduced trend of change.
5. A virtual control system for direct current, comprising: the device comprises a prediction module, a first control module, a second control module and a recovery module;
the prediction module is used for predicting the change trend of the direct current;
the first control module generates virtual current with an increasing change trend at the initial stage of fault development and the initial stage of direct current change, and the virtual current is superposed on an actual direct current measurement value and used for direct current control to accelerate the control speed of the direct current;
the second control module generates virtual current with reduced variation trend after the control action is effective and the direct current is restrained, and the virtual current is superposed on an actual direct current measurement value and used for direct current control, so that the control speed of the direct current is slowed down, and overshoot is restrained;
the recovery module adopts the virtual current with the reduced variation trend for the direct current control in the recovery stage of the direct current, so that the control speed of the direct current is accelerated, and the direct current is recovered to the instruction value as soon as possible.
6. The control system of claim 5, wherein in the first control module, the actual direct current is in an increasing trend, and the actual direct current at the current moment is subtracted from the actual direct current at the previous moment to generate a virtual current with an increasing trend of change.
7. The control system of claim 5, wherein in the second control module, the actual direct current is in a downward trend, and the actual direct current at the current moment is subtracted from the actual direct current at the previous moment to generate a virtual current with a reduced trend of change.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011449372.4A CN112636379A (en) | 2020-12-09 | 2020-12-09 | Virtual control method and system for direct current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011449372.4A CN112636379A (en) | 2020-12-09 | 2020-12-09 | Virtual control method and system for direct current |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112636379A true CN112636379A (en) | 2021-04-09 |
Family
ID=75309682
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011449372.4A Pending CN112636379A (en) | 2020-12-09 | 2020-12-09 | Virtual control method and system for direct current |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112636379A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04319717A (en) * | 1991-04-18 | 1992-11-10 | Toyo Electric Mfg Co Ltd | Power compensating device |
| US20080212342A1 (en) * | 2005-09-22 | 2008-09-04 | Siemens Aktiengesellschaft | Control Method for Direct-Current Transmission |
| WO2014107938A1 (en) * | 2013-01-08 | 2014-07-17 | 广东志成冠军集团有限公司 | Current source type rectifier and grid-connected control method based on virtual resistor |
| CN105633941A (en) * | 2015-01-20 | 2016-06-01 | 华北电力大学 | Commutation failure suppression method based on virtual current limiter |
| US20180006462A1 (en) * | 2015-01-21 | 2018-01-04 | Nr Electric Co., Ltd. | High voltage direct current power transmission series valve group control device |
| CN110474358A (en) * | 2019-08-28 | 2019-11-19 | 华北电力大学（保定） | Inhibit the control method of continuous commutation failure under extra-high voltage direct-current layer-specific access mode |
| CN111525588A (en) * | 2020-04-08 | 2020-08-11 | 南方电网科学研究院有限责任公司 | Control method and device for voltage stabilization of direct current power transmission system and storage medium |
-
2020
- 2020-12-09 CN CN202011449372.4A patent/CN112636379A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04319717A (en) * | 1991-04-18 | 1992-11-10 | Toyo Electric Mfg Co Ltd | Power compensating device |
| US20080212342A1 (en) * | 2005-09-22 | 2008-09-04 | Siemens Aktiengesellschaft | Control Method for Direct-Current Transmission |
| WO2014107938A1 (en) * | 2013-01-08 | 2014-07-17 | 广东志成冠军集团有限公司 | Current source type rectifier and grid-connected control method based on virtual resistor |
| CN105633941A (en) * | 2015-01-20 | 2016-06-01 | 华北电力大学 | Commutation failure suppression method based on virtual current limiter |
| US20180006462A1 (en) * | 2015-01-21 | 2018-01-04 | Nr Electric Co., Ltd. | High voltage direct current power transmission series valve group control device |
| CN110474358A (en) * | 2019-08-28 | 2019-11-19 | 华北电力大学（保定） | Inhibit the control method of continuous commutation failure under extra-high voltage direct-current layer-specific access mode |
| CN111525588A (en) * | 2020-04-08 | 2020-08-11 | 南方电网科学研究院有限责任公司 | Control method and device for voltage stabilization of direct current power transmission system and storage medium |
Non-Patent Citations (3)
| Title |
|---|
| ZEHONG LIU等: "Research on key technologies in ±1100 kV ultra-high voltage DC transmission", HIGH VOLTAGE, vol. 3, no. 4, 31 December 2018 (2018-12-31), XP006076324, DOI: 10.1049/hve.2018.5023 * |
| 王勇等: "抑制直流连续换相失败的直流电流指令值优化策略", 电力工程技术, vol. 39, no. 3, 31 May 2020 (2020-05-31) * |
| 马为民等: "改变直流电流控制器特性抑制次同步振荡的机理及实现", 高电压技术, vol. 44, no. 7, 31 July 2018 (2018-07-31) * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6084863B2 (en) | Power converter for grid connection | |
| Salimin et al. | Simulation analysis of DVR performance for voltage sag mitigation | |
| CN109149595B (en) | Phase modulator and extra-high voltage direct current converter station voltage reactive power coordination control method and system | |
| CN111082430B (en) | Phase modulator constant voltage control method, system and medium coordinated with reactive voltage control of extra-high voltage direct current converter station | |
| CN108110783B (en) | Method and device for coordination control between synchronous phase modulator and LCC-HVDC | |
| CN107809119B (en) | Optimization method for parameters of current controller of high-voltage direct current system | |
| EP3437184A2 (en) | System and method for consistent speed regulation in a variable frequency drive | |
| CN113991705A (en) | Wind power grid-connected system frequency modulation control method with energy storage wind power plant participating in primary frequency modulation control | |
| Nikolaev et al. | The dynamic operation investigation of an active rectifier control system with igct-thyristor switching angle table selection function | |
| JP7055998B2 (en) | Static VAR compensator and control method of the device | |
| CN112636379A (en) | Virtual control method and system for direct current | |
| CN110838716B (en) | Transformer starting impact current suppression system and method | |
| CN111342472B (en) | SVC (static var compensator) optimization control method and device for inhibiting direct-current continuous commutation failure | |
| CN112821439A (en) | Feedforward control method and device of flexible direct current converter | |
| CN108418257A (en) | Photovoltaic virtual synchronous machine light stores up control method for coordinating and device | |
| CN112134296B (en) | Three-level static var generator with auxiliary voltage sharing and voltage sharing method thereof | |
| JP2016032325A (en) | Power conversion device for system interconnection | |
| CN110994641B (en) | Method for inhibiting large-amplitude oscillation of direct-current transmission engineering power | |
| CN109039097B (en) | Variable frequency control method and device, shore power system and storage medium | |
| CN114665500A (en) | Coordination control method and system for restraining overvoltage of power grid | |
| CN113552430A (en) | Converter transient stability determination method and device based on critical indexes | |
| JP2022148986A (en) | Grid-connected power conversion device and control method for grid-connected power conversion device | |
| CN112636378A (en) | Dynamic parameter control method and system based on prediction of direct current change trend | |
| CN113765121B (en) | VSC/LCC parallel hybrid multi-feed system commutation failure recovery method and system | |
| CN111756051B (en) | Direct-current transmission reactive compensation device, control method and system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |