CN109066761B - Control method for direct current system ground conversion - Google Patents
Control method for direct current system ground conversion Download PDFInfo
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- CN109066761B CN109066761B CN201810996071.XA CN201810996071A CN109066761B CN 109066761 B CN109066761 B CN 109066761B CN 201810996071 A CN201810996071 A CN 201810996071A CN 109066761 B CN109066761 B CN 109066761B
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 11
- 238000000034 method Methods 0.000 title claims abstract description 10
- 230000009467 reduction Effects 0.000 claims description 5
- 230000005540 biological transmission Effects 0.000 abstract description 4
- 239000002184 metal Substances 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
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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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- 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
- H02J3/001—Methods to deal with contingencies, e.g. abnormalities, faults or failures
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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 invention relates to a control method for direct current system ground conversion, and belongs to the field of power electronics and flexible direct current transmission. The invention comprises the following steps: (1) detecting faults in real time, and if the grounding point has faults, judging the type of the faults; (2) when the fault type is a slight fault, firstly putting in a standby grounding point, and then withdrawing the fault grounding point; (3) when the fault type is a serious fault, the spare grounding point is directly put into use, and the problem that the direct current system cannot stably operate when the grounding point is failed due to the fact that a single grounding point is configured is solved. The invention realizes the mutual conversion between the grounding points, ensures the stable operation of the direct current system and has good engineering application prospect.
Description
Technical Field
The invention relates to a control method for direct current system ground conversion, and belongs to the field of power electronics and flexible direct current transmission.
Background
With the rapid development of power electronic technology, a flexible direct current transmission technology with a Voltage Source Converter (VSC) as a core component becomes the mainstream trend of the development of a future power system, and considering the outstanding advantages of large-scale centralized access of new energy power generation, reduction of power supply corridors, reduction of power transmission loss, improvement of power supply quality and power supply reliability, the flexible direct current grid is considered to be a great revolutionary technology of the development of the power system.
The flexible direct-current power grid is a novel power network which is directly interconnected with direct-current lines in a direct-current field, can realize flexible independent control of power and friendly access of new energy power generation, can provide better power supply reliability and system redundancy, has stronger adaptability, flexible and safe power flow control and the like, and is considered as an ideal networking scheme in the aspects of large-scale distributed renewable energy access, island power supply, sending out in an offshore wind power plant cluster, novel urban power grid construction and the like, and is also one of important directions of development of future smart power grids.
For a multi-terminal flexible direct-current power grid adopting a bipolar connection scheme, if a single grounding point is configured, when the grounding point fails, a direct-current system cannot stably operate.
Disclosure of Invention
The invention aims to provide a control method for ground conversion of a direct current system, which is used for solving the problem that the direct current system cannot stably run when a single ground point is configured and the ground point fails.
In order to achieve the above object, the present invention provides a method for controlling ground conversion of a dc system, comprising the following steps:
(1) detecting faults in real time, and if the grounding point has faults, judging the type of the faults;
(2) when the fault type is a slight fault, firstly putting in a standby grounding point, and then withdrawing the fault grounding point;
(3) when the fault type is a serious fault, the spare grounding point is directly put into use.
Because the single ground point is configured, if the ground point is damaged and the double poles are not balanced in operation, the system can only be shut down, so that the system is unstable, a plurality of ground points are configured, mutual conversion among the ground points can be realized, the stable operation of a direct current system is ensured, and the method has a good engineering application prospect.
In the step (2), when the fault type is a slight fault, firstly processing according to the system running state, and then putting into a standby grounding point; the means for processing according to the system running state comprises:
if the system running state is a unipolar running state, controlling each converter station to perform power reduction running;
and if the system operation state is a bipolar operation state, controlling the power balance among the poles of the converter stations.
Before the grounding point is converted, the bipolar power balance is realized or the current flowing through the metal return wire is minimum by controlling the power of all converter stations, the electrical impact in the grounding point transfer process can be effectively reduced, the metal return wire is prevented from overflowing, and the stable operation of a direct current system is ensured.
Drawings
FIG. 1 is a schematic diagram of a flexible DC power grid system of the present invention;
fig. 2 is a schematic diagram of a ground point conversion control method according to the present invention.
Detailed Description
The following further describes embodiments of the present invention with reference to the drawings.
The basic structure of the flexible direct current grid system related to the embodiment is shown in fig. 1, the flexible direct current grid system at least comprises three-terminal flexible direct current converter stations, each terminal converter station adopts a bipolar structure, each voltage source type converter has control modes such as direct current voltage, active power, reactive power, alternating current voltage and the like, and each converter station is connected with other converter stations through a mesh-shaped direct current line.
In this embodiment, the converter station a and the converter station D are respectively configured with grounding points, and the steady-state operation conditions of the system are as follows: d converter station decides DC voltage control, DC side metal return wire grounding point is put into operation, A converter station decides active power control, DC side metal return wire grounding point is standby, B converter station and C converter station all decide active power control, DC side has no grounding point.
The grounding conversion of the direct current system is carried out through the following steps:
as shown in fig. 2, the running condition of the grounding point of the dc system in the input state shown in fig. 1 is monitored in real time, if the grounding point of the D converter station is detected to have a fault, the detected fault type is determined, and when the fault type of the D converter station is detected to be a slight fault, the running state of the system is determined, and if the running state of the flexible dc power grid system is in the monopolar running state, the standby grounding point of the a converter station is input first and the fault grounding point of the D converter station is withdrawn after the power reduction running of the a converter station, the B converter station, the C converter station and the D converter station at the same time, so that the current flowing through the metal; and if the operation state of the flexible direct current grid system is a bipolar operation state, balancing the interelectrode power of the converter station A, the converter station B, the converter station C and the converter station D, so that the current flowing through the metal return wire is minimum, firstly putting the standby grounding point of the converter station A, and then withdrawing the fault grounding point of the converter station D.
And when the D converter station fault type is detected to be a serious fault, directly putting the standby grounding point of the A converter station.
While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that the foregoing and various other changes, omissions and deviations in the form and detail thereof may be made without departing from the scope of this invention as defined in the appended claims.
Claims (1)
1. A control method for direct current system ground conversion is characterized by comprising the following steps:
(1) detecting faults in real time, and if the grounding point has faults, judging the type of the faults;
(2) when the fault type is a slight fault, firstly putting in a standby grounding point, and then withdrawing the fault grounding point;
(3) when the fault type is a serious fault, directly putting into a standby grounding point;
in the step (2), when the fault type is a slight fault, firstly, processing is carried out according to the system operation state, and then a standby grounding point is put into use; the means for processing according to the system running state comprises:
if the system running state is a unipolar running state, controlling each converter station to perform power reduction running;
and if the system operation state is a bipolar operation state, controlling the power balance among the poles of the converter stations.
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| CN201810996071.XA CN109066761B (en) | 2018-08-29 | 2018-08-29 | Control method for direct current system ground conversion |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810996071.XA CN109066761B (en) | 2018-08-29 | 2018-08-29 | Control method for direct current system ground conversion |
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| Publication Number | Publication Date |
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| CN109066761A CN109066761A (en) | 2018-12-21 |
| CN109066761B true CN109066761B (en) | 2021-03-05 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105762825A (en) * | 2016-04-06 | 2016-07-13 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Direct current grounding electrode system and interconnection method |
| CN206270446U (en) * | 2016-12-09 | 2017-06-20 | 上海吉泰电阻器有限公司 | A kind of grounding resistor intelligent monitor system for mesolow electrical power trans mission/distribution system |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013115915A1 (en) * | 2012-01-31 | 2013-08-08 | Atlantic Grid Operations A., Llc | Control and protection of a dc power grid |
| CN105071373B (en) * | 2015-08-27 | 2018-03-30 | 中国电力科学研究院 | The configuration system and method for dc switch field in a kind of flexible direct current power transmission system |
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2018
- 2018-08-29 CN CN201810996071.XA patent/CN109066761B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105762825A (en) * | 2016-04-06 | 2016-07-13 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Direct current grounding electrode system and interconnection method |
| CN206270446U (en) * | 2016-12-09 | 2017-06-20 | 上海吉泰电阻器有限公司 | A kind of grounding resistor intelligent monitor system for mesolow electrical power trans mission/distribution system |
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| CN109066761A (en) | 2018-12-21 |
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