CN109301801B - Mutual grounding electrode wiring structure and bipolar neutral line differential protection action method - Google Patents
Mutual grounding electrode wiring structure and bipolar neutral line differential protection action method Download PDFInfo
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- CN109301801B CN109301801B CN201811391312.4A CN201811391312A CN109301801B CN 109301801 B CN109301801 B CN 109301801B CN 201811391312 A CN201811391312 A CN 201811391312A CN 109301801 B CN109301801 B CN 109301801B
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- grounding electrode
- direct current
- disconnecting link
- bipolar
- grounding
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/28—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for meshed systems
-
- 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]
Abstract
The invention relates to a mutual grounding electrode wiring structure and a bipolar neutral line differential protection action method, which comprise a first isolation disconnecting link, wherein a second direct current grounding electrode circuit is connected to a second direct current circuit; the other end of the third isolation disconnecting link is connected with one end of a DC/DC grounding electrode circuit connected to the DC/DC line in parallel; an EBS switch is connected in series between the first isolation disconnecting link and the second isolation disconnecting link, and a second IDE_OBP is arranged between the EBS and the second isolation disconnecting link; a first IDE_OBP is arranged between the third isolating switch and the return direct-current line. The invention ensures no dead zone in protection and ensures safe and reliable operation when the double-circuit direct current is used for the grounding electrode; and ensures normal operation of non-fault direct current as much as possible, and improves the reliability of direct current operation.
Description
Technical Field
The invention relates to the field of extra-high voltage direct current engineering, in particular to a dual-return direct current mutual grounding electrode wiring structure and a bipolar neutral line differential protection action method.
Background
The grounding electrode is an important component in high-voltage direct-current transmission, provides a zero potential clamping point for a direct-current loop, and forms a loop through the grounding electrode and the earth when a monopole earth loop operates. The extra-high voltage direct current engineering in the prior art is composed of a rectifying station, a direct current circuit, a grounding electrode circuit and an inversion station. Once the earth is extremely unavailable (faulty or overhauled), the direct current is forced to be shut down. In order to reduce the engineering outage rate and improve the economic benefit, two direct current engineering adjacent to a station site can mutually use the grounding electrode, and when the grounding electrode of one direct current engineering is unavailable, the grounding electrode of the other direct current engineering is used for forming a power transmission loop, so that the power is normally transmitted. In order to achieve the above purpose, as shown in fig. 1, two dc projects close to the site can be provided with a mutual grounding electrode connection loop and related devices such as a change-over switch and a disconnecting link, so as to realize the mutual grounding electrode and improve the reliability and economic benefit of dc operation.
When the two-circuit direct current is used for the grounding electrode, the protection configuration and the action strategy of the area are also required to be adjusted due to the change of the connection modes of the bipolar electrode and the grounding electrode area. The bipolar neutral differential protection is used as an important protection of a bipolar area and is used for detecting the ground fault from a neutral bus to a ground electrode lead, and when the two-circuit direct current is used for the ground electrode mutually, the protection action strategy of the bipolar neutral differential protection needs to be adjusted to adapt to a new wiring form.
Disclosure of Invention
Aiming at the problems, the invention aims to provide an inter-use grounding electrode wiring structure and a bipolar neutral wire differential protection action method, which can ensure protection without dead zones and ensure safe and reliable operation during double-circuit direct current inter-use grounding electrode.
In order to achieve the above purpose, the present invention adopts the following technical scheme: the utility model provides an interwork earthing pole wiring structure, it sets up on returning the earthing pole connecting wire between first direct current and the second direct current, characterized by including first isolation switch, second isolation switch, third isolation switch, EBS, first IDE_OBP and second IDE_OBP; wherein, EBS is the grounding electrode connecting wire switch, IDE_OBP is the mutual grounding electrode current measurement CT; the second DC circuit is connected with a second DC grounding electrode circuit, one end of the first isolation disconnecting link is connected with one end of the second DC grounding electrode circuit in parallel, and the other end of the first isolation disconnecting link is connected with one end of the third isolation disconnecting link in series through the second isolation disconnecting link; the other end of the third isolation disconnecting link is connected with one end of a DC/DC grounding electrode circuit connected to the DC/DC line in parallel; the EBS is connected in series between the first isolation disconnecting link and the second isolation disconnecting link, and the second IDE_OBP is arranged between the EBS and the second isolation disconnecting link; the first IDE_OBP is arranged between the third isolating switch and the return direct-current line.
Further, two grounding branches are connected in parallel between the second isolation disconnecting link and the third isolation disconnecting link; the two grounding branches are respectively provided with a grounding disconnecting link, one end of each grounding disconnecting link is connected to a grounding electrode connecting line between the second isolation disconnecting link and the third isolation disconnecting link, and the other end of each grounding disconnecting link is grounded.
Further, the direct current grounding electrode circuit and the two direct current grounding electrode circuits are grounded through the grounding electrode circuit.
A bipolar neutral line differential protection action method based on the connection structure when the grounding electrode is used for the mutual use comprises the following steps: 1) When the EBS switch is in the closing position, the two direct currents are in the state of the mutual grounding electrode; when the EBS switch is in the split position, the two direct currents are in an independent running state of the grounding electrode; 2) When the two-circuit direct current mutually uses the grounding electrode, the IDE_OBP is included in the criterion of the bipolar neutral line differential protection of the two-circuit direct current; 3) When the grounding electrode is used for the mutual grounding electrode, if a certain back direct current bipolar neutral line differential protection action is performed, the back direct current performs the protection action and simultaneously sends an action signal to the other back direct current of the mutual grounding electrode, and whether bipolar operation is performed is judged; 4) If the protection still acts, blocking the direct current which is not available to the grounding electrode, judging whether the direct current which is available to the grounding electrode runs in a bipolar mode, and pulling the EBS; 5) If the protection still acts, locking the direct current which is available to the grounding electrode; 6) When the two-circuit direct current recovery grounding electrode independently operates, the criterion of the bipolar neutral line differential protection no longer adopts IDE_OBP, and the action strategy is recovered to the strategy during independent operation.
Further, in the step 3), determining whether the bipolar operation is the bipolar operation includes the steps of: 3.1 If the bipolar neutral differential protection action returns to bipolar operation, performing polar balancing; if the operation is monopolar operation, performing phase shifting restarting; 3.2 If the other back direct current of the inter-used grounding electrode is bipolar operation, sending a pole balance command to the other back direct current; and if the other direct current of the inter-used grounding electrode is in monopolar operation, sending a phase shift restarting command.
Further, in the step 4), it is determined whether the dc voltage available to the ground electrode is bipolar operation, including the steps of: 4.1 If the available direct current of the grounding electrode is bipolar operation, directly pulling the EBS after locking the unavailable direct current of the grounding electrode; judging whether the protection still acts or not, if yes, locking the available direct current of the grounding electrode, otherwise, normally operating the available direct current of the grounding electrode; 4.2 If the available direct current of the grounding electrode is in monopolar operation, after the unavailable direct current of the grounding electrode is blocked, the available direct current of the grounding electrode executes a phase shift command, and after the current flowing through the EBS is smaller than a preset fixed value, the EBS is pulled open.
Due to the adoption of the technical scheme, the invention has the following advantages: 1. the inter-use grounding electrode wiring structure can realize inter-use of the grounding electrodes of two direct currents, and when the grounding electrode is unavailable, the grounding electrode of the other direct current is used for normal power transmission, so that the economic benefit of direct current power transmission is improved. 2. The bipolar neutral line differential protection range covers the double-circuit grounding electrode connecting line area, so that the related protection areas overlap each other, no dead zone is ensured for protection, and safe and reliable operation during double-circuit Direct Current (DC) interaction grounding electrode is ensured. 3. The protection strategy is flexible and reliable, and ensures normal operation of the non-fault DC system as much as possible while eliminating and isolating faults, and improves the reliability of DC operation.
Drawings
FIG. 1 is a schematic diagram of a two-circuit DC engineering main connection for an inter-use ground;
FIG. 2 is a schematic diagram of a dual-loop DC-to-AC ground connection in accordance with the present invention;
FIG. 3 is a schematic diagram of the differential protection operation of the bipolar neutral line when the earth electrodes are used for each other.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and examples.
As shown in fig. 2, the present invention provides an inter-working grounding electrode connection structure, which is disposed on a grounding electrode connection line between a first dc and a second dc, and includes a first isolation switch Q31, a second isolation switch Q32, a third isolation switch Q33, a grounding electrode connection line switch (EBS), a first ide_obp (inter-working grounding electrode current measurement CT of the first dc), and a second ide_obp (inter-working grounding electrode current measurement CT of the second dc).
The two DC circuits are connected with two DC grounding electrode circuits, one end of the first isolation disconnecting link Q31 is connected with one end of the two DC grounding electrode circuits in parallel, and the other end of the first isolation disconnecting link Q31 is connected with one end of the third isolation disconnecting link Q33 in series through the second isolation disconnecting link Q32. The other end of the third isolating switch 33 is connected in parallel with one end of a DC-DC grounding electrode circuit connected to the DC-DC line. An EBS switch is connected in series between the first isolation disconnecting link Q31 and the second isolation disconnecting link Q32; a second IDE_OBP is arranged between the EBS and the second isolating switch Q32; a first ide_obp is provided between the third isolation switch 33 and the return dc line.
In the above embodiment, two grounding branches are connected in parallel between the second isolation switch Q32 and the third isolation switch Q33. The two grounding branches are provided with grounding disconnecting links, one end of each grounding disconnecting link is connected to a grounding electrode connecting line between the second isolation disconnecting link Q32 and the third isolation disconnecting link Q33, and the other end of each grounding disconnecting link is grounded.
In the above embodiments, the dc-dc grounding electrode circuit and the dc-dc grounding electrode circuit are the same and are grounded through the grounding electrode circuit.
In summary, when the inter-use grounding electrode wiring structure of the present invention is used, when the first isolation knife switch Q31, the second isolation knife switch Q32, the third isolation knife switch Q33, and the EBS switch on the grounding electrode connection line are in a closed state, the grounding knife switch is in an open state, the inter-use grounding electrode is in a connection state, and when the fault grounding electrode is in an isolation state, the dual-return direct current is considered to be in an inter-use grounding electrode state.
As shown in fig. 3, based on the above wiring structure, the present invention further provides a bipolar neutral differential protection operation method when the grounding electrode is used for the mutual use, comprising the following steps:
1) When the EBS switch is in the closing position, the two direct currents are in the state of the mutual grounding electrode; when the EBS switch is in the split position, the two direct currents are in an independent running state of the grounding electrode;
2) When the two-circuit direct current mutually uses the grounding electrode, the IDE_OBP is included in the criterion of the bipolar neutral line differential protection of the two-circuit direct current;
3) When the grounding electrode is used for the mutual grounding electrode, if a certain back direct current bipolar neutral line differential protection action is performed, the back direct current performs the protection action and simultaneously sends an action signal to the other back direct current of the mutual grounding electrode, and whether bipolar operation is performed is judged;
4) If the protection still acts, blocking the direct current which is not available to the grounding electrode, judging whether the direct current which is available to the grounding electrode runs in a bipolar mode, and pulling the EBS;
5) If the protection still acts, locking the direct current which is available to the grounding electrode;
6) When the two-circuit direct current recovery grounding electrode independently operates, the criterion of the bipolar neutral line differential protection no longer adopts IDE_OBP, and the action strategy is recovered to the strategy during independent operation.
In the step 3), the step of judging whether the bipolar operation is performed comprises the following steps:
3.1 If the bipolar neutral differential protection action returns to bipolar operation, performing polar balancing; if the operation is monopolar operation, performing phase shifting restarting;
3.2 If the other back direct current of the inter-used grounding electrode is bipolar operation, sending a pole balance command to the other back direct current; and if the other direct current of the inter-used grounding electrode is in monopolar operation, sending a phase shift restarting command.
In the step 4), the step of judging whether the direct current available to the grounding electrode is bipolar operation comprises the following steps:
4.1 If the available direct current of the grounding electrode is bipolar operation, directly pulling the EBS after locking the unavailable direct current of the grounding electrode; judging whether the protection still acts or not, if yes, locking the available direct current of the grounding electrode, otherwise, normally operating the available direct current of the grounding electrode;
4.2 If the available direct current of the grounding electrode is in monopolar operation, after the unavailable direct current of the grounding electrode is blocked, the available direct current of the grounding electrode executes a phase shift command, and after the current flowing through the EBS is smaller than a preset fixed value, the EBS is pulled open.
The foregoing embodiments are only illustrative of the present invention, and the structures, arrangement of parts and steps may be varied, and modifications and equivalents of the individual parts and steps based on the principles of the present invention should not be excluded from the scope of the present invention.
Claims (3)
1. The bipolar neutral wire differential protection action method based on the inter-use grounding electrode of the inter-use grounding electrode wiring structure is characterized in that the inter-use grounding electrode wiring structure is arranged on a grounding electrode connecting wire between a first direct current and a second direct current and comprises a first isolation disconnecting link, a second isolation disconnecting link, a third isolation disconnecting link, an EBS, a first IDE_OBP and a second IDE_OBP; wherein, EBS is the grounding electrode connecting wire switch, IDE_OBP is the mutual grounding electrode current measurement CT;
the second DC circuit is connected with a second DC grounding electrode circuit, one end of the first isolation disconnecting link is connected with one end of the second DC grounding electrode circuit in parallel, and the other end of the first isolation disconnecting link is connected with one end of the third isolation disconnecting link in series through the second isolation disconnecting link; the other end of the third isolation disconnecting link is connected with one end of a DC/DC grounding electrode circuit connected to the DC/DC line in parallel; the EBS is connected in series between the first isolation disconnecting link and the second isolation disconnecting link, and the second IDE_OBP is arranged between the EBS and the second isolation disconnecting link; the first IDE_OBP is arranged between the third isolating switch and the return direct-current line;
the bipolar neutral line differential protection action method during the mutual grounding electrode comprises the following steps:
1) When the EBS switch is in the closing position, the two direct currents are in the state of the mutual grounding electrode; when the EBS switch is in the split position, the two direct currents are in an independent running state of the grounding electrode;
2) When the two-circuit direct current mutually uses the grounding electrode, the IDE_OBP is included in the criterion of the bipolar neutral line differential protection of the two-circuit direct current;
3) When the grounding electrode is used for the mutual grounding electrode, if a certain back direct current bipolar neutral line differential protection action is performed, the back direct current performs the protection action and simultaneously sends an action signal to the other back direct current of the mutual grounding electrode, and whether bipolar operation is performed is judged;
4) If the protection still acts, blocking the direct current which is not available to the grounding electrode, judging whether the direct current which is available to the grounding electrode runs in a bipolar mode, and pulling the EBS;
5) If the protection still acts, locking the direct current which is available to the grounding electrode;
6) When the two-circuit direct current recovery grounding electrode independently operates, the criterion of the bipolar neutral line differential protection does not adopt IDE_OBP any more, and the action strategy is recovered to be the strategy during independent operation;
in the step 3), judging whether the bipolar operation is the bipolar operation comprises the following steps:
3.1 If the bipolar neutral differential protection action returns to bipolar operation, performing polar balancing; if the operation is monopolar operation, performing phase shifting restarting;
3.2 If the other back direct current of the inter-used grounding electrode is bipolar operation, sending a pole balance command to the other back direct current; if another back direct current of the inter-used grounding electrode is in monopolar operation, a phase shift restarting command is sent;
in the step 4), it is determined whether the dc voltage available to the ground electrode is bipolar operation, including the steps of:
4.1 If the available direct current of the grounding electrode is bipolar operation, directly pulling the EBS after locking the unavailable direct current of the grounding electrode; judging whether the protection still acts or not, if yes, locking the available direct current of the grounding electrode, otherwise, normally operating the available direct current of the grounding electrode;
4.2 If the available direct current of the grounding electrode is in monopolar operation, after the unavailable direct current of the grounding electrode is blocked, the available direct current of the grounding electrode executes a phase shift command, and after the current flowing through the EBS is smaller than a preset fixed value, the EBS is pulled open.
2. The method for differential protection operation of a bipolar neutral wire when a ground electrode is shared by both of claim 1, wherein: two grounding branches are connected in parallel between the second isolation disconnecting link and the third isolation disconnecting link; the two grounding branches are respectively provided with a grounding disconnecting link, one end of each grounding disconnecting link is connected to a grounding electrode connecting line between the second isolation disconnecting link and the third isolation disconnecting link, and the other end of each grounding disconnecting link is grounded.
3. A method for differential protection of a bipolar neutral line when a ground electrode is shared by the two electrodes as claimed in claim 1 or 2, wherein: the return direct current grounding electrode circuit and the return two direct current grounding electrode circuits are grounded through the grounding electrode circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201811391312.4A CN109301801B (en) | 2018-11-21 | 2018-11-21 | Mutual grounding electrode wiring structure and bipolar neutral line differential protection action method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201811391312.4A CN109301801B (en) | 2018-11-21 | 2018-11-21 | Mutual grounding electrode wiring structure and bipolar neutral line differential protection action method |
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| CN109301801A CN109301801A (en) | 2019-02-01 |
| CN109301801B true CN109301801B (en) | 2023-09-29 |
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| CN110120653B (en) * | 2019-04-30 | 2021-03-23 | 天津大学 | Pilot traveling wave differential protection method suitable for symmetrical bipolar direct current line |
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| CN205283127U (en) * | 2015-11-13 | 2016-06-01 | 南方电网科学研究院有限责任公司 | Topological structure of many times high voltage direct current sharing earthing poles |
| CN105790211A (en) * | 2015-12-31 | 2016-07-20 | 国家电网公司 | Method for protecting earth electrode line |
| CN106385010A (en) * | 2016-09-09 | 2017-02-08 | 南京南瑞继保工程技术有限公司 | Ultra-high voltage direct current earth electrode earth electrode lead double end unbalance protection method |
| CN106385047A (en) * | 2016-11-18 | 2017-02-08 | 中国能源建设集团广东省电力设计研究院有限公司 | Full-bridge topological bipolar wiring flexible DC converter station and neutral line wiring apparatus thereof |
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2018
- 2018-11-21 CN CN201811391312.4A patent/CN109301801B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204230894U (en) * | 2014-10-24 | 2015-03-25 | 中国南方电网有限责任公司超高压输电公司广州局 | A kind of One Common Earthing Electrode operation interlock circuit |
| CN205283127U (en) * | 2015-11-13 | 2016-06-01 | 南方电网科学研究院有限责任公司 | Topological structure of many times high voltage direct current sharing earthing poles |
| CN105790211A (en) * | 2015-12-31 | 2016-07-20 | 国家电网公司 | Method for protecting earth electrode line |
| CN106385010A (en) * | 2016-09-09 | 2017-02-08 | 南京南瑞继保工程技术有限公司 | Ultra-high voltage direct current earth electrode earth electrode lead double end unbalance protection method |
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