CN104578128A - Islanding-to-networking switching method for flexible direct current power transmission system - Google Patents
Islanding-to-networking switching method for flexible direct current power transmission system Download PDFInfo
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- CN104578128A CN104578128A CN201410811863.7A CN201410811863A CN104578128A CN 104578128 A CN104578128 A CN 104578128A CN 201410811863 A CN201410811863 A CN 201410811863A CN 104578128 A CN104578128 A CN 104578128A
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- current
- transmission system
- flexible direct
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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
- H02J3/40—Synchronising a generator for connection to a network or to another generator
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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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- Remote Monitoring And Control Of Power-Distribution Networks (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
Abstract
The invention discloses a method for detecting the change of an operating mode of a power grid into a networking state under the islanding operation of a flexible direct current power transmission system. A control system determines that the flexible direct current power transmission system under the islanding operation enters the networking state by detecting the network side voltage and judging the on-off position of a switch, and switches from an islanding operation control mode to a networking control mode; the mode is steadily switched into the networking control mode by changing a power instruction at a switching moment and performing phase tracking on a current power grid voltage mode, and the system keeps operation continuously.
Description
Technical field
The invention belongs to field of power electronics, particularly under a kind of flexible direct current power transmission system islet operation, detection of grid changes of operating modes enters networking state method.
Background technology
Flexible DC power transmission adopts voltage source converter, independently, fast can control active power and reactive power, thus improve the stability of system, suppress the fluctuation of system frequency and voltage, improve the steady-state behaviour of synchronization AC system.Flexible DC power transmission at new-energy grid-connected, distributed power generation is grid-connected, island with power, urban distribution network are powered etc., and field has larger advantage, therefore the research of flexible DC power transmission correlation technique has great importance.
Flexible direct current power transmission system be in islet operation time, in current conversion station, near-end combined floodgate incoming transport electrical network or far-end switch close a floodgate, active electrical network operation is entered in flexible direct current converter station parallel connection, need flexible direct current system to be transformed into the active operation control method of networking from current islet operation control mode, keep DC transmission system to continue to run.
When under flexible direct current power transmission system islet operation, detection of grid changes of operating modes enters networking state; need accurately to detect flexible direct current power transmission system and enter the networking moment; otherwise the long period can cause Out of step; flexible direct current power transmission system is caused to be stopped transport; also need steadily to switch to networking mode to run simultaneously; avoid switching and cause overcurrent or overvoltage phenomenon instantaneously, cause flexible direct current power transmission system protection act out of service.Under current flexible direct current power transmission system islet operation, detection of grid changes of operating modes enters the detection method of networking and takes over seamlessly control and have no relevant report.
Summary of the invention
Object of the present invention, under being to provide a kind of flexible direct current power transmission system islet operation, detection of grid changes of operating modes enters networking state method, ensures that flexible direct current power transmission system transfers networking operation to from islet operation smoothly.
In order to reach above-mentioned purpose, the technical solution used in the present invention is:
Under a kind of flexible direct current power transmission system islet operation, detection of grid changes of operating modes enters networking state method, under it is characterized in that flexible direct-current transmission system converter station islet operation situation, detect transmission system and connect alternating-current switch position, if connect alternating-current switch to be in a point position, comprise the steps:
(1) voltage on line side has at least a phase voltage to exceed threshold value, and through detecting time delay t, open islanding detect condition, enters step (2), otherwise close this islanding detect condition, get back to step (1);
(2) judge that whether connect alternating-current switch is changed to co-bit from a point position, as change enters step (3), enters step (1) as not having change;
(3) the control system phase-locked link setting current voltage on line side of locking or voltage on valve side phase place, starts control mode conversion simultaneously, controls transitions to Active control mode by current flexible direct-current transmission system converter station isolated island;
In scheme, under flexible direct current power transmission system islet operation, detection of grid changes of operating modes enters networking state method, and connecting alternating-current switch position can also can asynchronous switch-on place in the distance at our station;
In above scheme, described in step (1), threshold value span is 0.1pu ~ 1.0pu, and detecting time delay t span is 0 ~ 1s;
The moment of the described control mode conversion of step (3) in above scheme, active power and reactive power instruction can maintain the runtime value of current active power and reactive power, can be also 0, rise to current runtime value gradually by slope.
The present invention also comprises a kind of isolated island and turns networking control device, it is characterized in that comprising alternating-current switch position detection unit, voltage on line side detecting unit, and control mode converting unit.
Described voltage on line side detecting unit detects voltage on line side, has at least a phase voltage to exceed threshold value, and continues for some time t, then open islanding detect condition.
Whether described alternating-current switch position detection unit, enter control mode converting unit by detecting transmission system connection alternating-current switch determining positions.
Described control mode converting unit, the phase-locked link of control system is utilized to set the current AC voltage-phase of locking, start control mode conversion simultaneously, control transitions to Active control mode by current flexible direct-current transmission system converter station isolated island, active power and reactive power instruction maintain the runtime value of current active power and reactive power.
The present invention also comprises a kind of flexible direct current power transmission system isolated island and turns networked system, it is characterized in that, comprise converter, top level control device and valve control device, wherein top level control device detects transmission system connection alternating-current switch position, if be in a point position, and voltage on line side has at least a phase voltage to exceed threshold value, and continue for some time t, then open islanding detect condition, then judge whether connect alternating-current switch is changed to co-bit from a point position, as change just sets the current AC voltage-phase of locking by the phase-locked link of the control system of top level control device, start control mode conversion simultaneously, Active control mode is controlled transitions to by current flexible direct-current transmission system converter station isolated island.
After adopting such scheme, beneficial effect of the present invention is:
Under a kind of flexible direct current power transmission system islet operation provided by the invention, detection of grid changes of operating modes enters networking state method, can take over seamlessly networking operation mode, can not impact to electrical network.
Accompanying drawing explanation
Fig. 1 is flexible direct current power transmission system dual station structural representation;
Fig. 2 is grid-connected detection power station control mode schematic diagram;
Fig. 3 is the control mode schematic diagram at constant DC voltage control station;
Fig. 4 is the grid-connected overhaul flow chart of flexible direct current under decoupled mode.
Embodiment
Below with reference to drawings and the specific embodiments, technical scheme of the present invention is described in detail.
As shown in Figure 1, be in the flexible direct current transmission converter station 201-202 of islet operation, 301-302 is load, 400-401 is AC network, far-end switch 102 does not close a floodgate, flexible direct current power transmission system 201-202 does not have incoming transport electrical network 101, near-end switch 103 is in a point position, flexible direct current power transmission system 201-202 is in island operation state, 202 is constant DC voltage control side, control mode is adopted to see Fig. 3, 201 adopt Fig. 2 control mode, Fig. 3 is constant DC voltage control mode, remain unchanged afterwards before the handover, in Fig. 2, grid-connected detection detects that networking state is just switched to real power control mode.Because near-end switch 103 is in a point position, 201 current conversion stations are in decoupled mode, and moment detection whether also net state, switch 103 closes a floodgate moment, detects (see Fig. 4) in accordance with the following steps and whether transfers networking state operation to by isolated island:
(1) in flexible direct-current transmission system converter station 201-202 islet operation situation, alternating-current switch 103 points of positions and voltage on line side 401 has at least a phase voltage to exceed threshold value, open islanding detect condition, enter step (2), otherwise close this islanding detect condition, get back to step (1)
(2) judging whether converter our station alternating-current switch 103 is changed to co-bit from a point position, as change enters step (3), entering step (1) as there is no change;
(3) current voltage on valve side phase place is followed the tracks of in the setting of control system phase-locked link, changing power instruction is zero energy instruction, start control mode conversion, current flexible direct-current transmission system converter station 201 controls transitions to Active control mode by isolated island, and this transfer process terminates simultaneously.
After switch 103 closes, if net side 401 is active, then converter 201 controls transitions to Active control mode according to above step from isolated island.In particular cases, net side 401 is passive states, and after switch 103 closes, step (1) is as long as middle voltage on line side 401 has a phase voltage high condition not meet, and close this networking testing conditions, converter 201 remains island operation state.Close a switch after 103, if converter 201 remains island operation state, continue to detect next stage switch 102 points of co-bits, step is the same, just voltage on line side is replaced by checking network side 400 voltage, step shown in same employing Fig. 4, only changes sense switch 102 points of co-bits and net side 400 place alternating voltage into.
The present invention also provides a kind of isolated island to turn networking control device, comprises alternating-current switch position detection unit, voltage on line side detecting unit, and control mode converting unit;
Described voltage on line side detecting unit detects voltage on line side, has at least a phase voltage to exceed threshold value, and continues for some time t, then open islanding detect condition;
Whether described alternating-current switch position detection unit, enter control mode converting unit by detecting transmission system connection alternating-current switch determining positions;
Described control mode converting unit, the phase-locked link of control system is utilized to set the current AC voltage-phase of locking, start control mode conversion simultaneously, control transitions to Active control mode by current flexible direct-current transmission system converter station isolated island, active power and reactive power instruction maintain the runtime value of current active power and reactive power.
The present invention also provides a kind of flexible direct current power transmission system isolated island to turn networked system, comprise converter, top level control device and valve control device, wherein top level control device detects transmission system connection alternating-current switch position, if be in a point position, and voltage on line side has at least a phase voltage to exceed threshold value, and continue for some time t, then open islanding detect condition, then judge whether connect alternating-current switch is changed to co-bit from a point position, as change just sets the current AC voltage-phase of locking by the phase-locked link of the control system of top level control device, start control mode conversion simultaneously, Active control mode is controlled transitions to by current flexible direct-current transmission system converter station isolated island.
Above embodiment is only and technological thought of the present invention is described, can not limit protection scope of the present invention with this, and every technological thought proposed according to the present invention, any change that technical scheme basis is done, all falls within scope.
Claims (7)
1. flexible direct current power transmission system isolated island turns a changing method for networking, it is characterized in that, in flexible direct-current transmission system converter station islet operation situation, detects transmission system and connects alternating-current switch position, if connect alternating-current switch to be in a point position, comprise the steps:
(1) if voltage on line side has at least a phase voltage to exceed threshold value, and continue for some time t, then open islanding detect condition, enters step (2), otherwise closes this islanding detect condition, get back to step (1);
(2) judge that whether connect alternating-current switch is changed to co-bit from a point position, as change enters step (3), enters step (1) as not having change;
(3) the current AC voltage-phase of control system phase-locked link setting locking, starts control mode conversion simultaneously, controls transitions to Active control mode by current flexible direct-current transmission system converter station isolated island.
2. a kind of flexible direct current power transmission system isolated island as claimed in claim 1 turns the changing method of networking, it is characterized in that, connects alternating-current switch position in our station or asynchronous switch-on place in the distance.
3. a kind of flexible direct current power transmission system isolated island as claimed in claim 1 turns the changing method of networking, and described in step (1), threshold value span is 0.1pu ~ 1.0pu, and detecting time delay t span is 0 ~ 1s.
4. a kind of flexible direct current power transmission system isolated island as claimed in claim 1 turns the changing method of networking, it is characterized in that, the moment of the conversion of control mode described in step (3), active power and reactive power instruction maintain the runtime value of current active power and reactive power.
5. a kind of flexible direct current power transmission system isolated island as claimed in claim 1 turns the changing method of networking, it is characterized in that, the moment of the conversion of control mode described in step (3), active power and reactive power instruction are 0, then rise to current runtime value gradually.
6. isolated island turns a networking control device, it is characterized in that comprising alternating-current switch position detection unit, voltage on line side detecting unit, and control mode converting unit;
Described voltage on line side detecting unit detects voltage on line side, has at least a phase voltage to exceed threshold value, and continues for some time t, then open islanding detect condition;
Whether described alternating-current switch position detection unit, enter control mode converting unit by detecting transmission system connection alternating-current switch determining positions;
Described control mode converting unit, the phase-locked link of control system is utilized to set the current AC voltage-phase of locking, start control mode conversion simultaneously, control transitions to Active control mode by current flexible direct-current transmission system converter station isolated island, active power and reactive power instruction maintain the runtime value of current active power and reactive power.
7. a flexible direct current power transmission system isolated island turns networked system, it is characterized in that, comprise converter, top level control device and valve control device, wherein top level control device detects transmission system connection alternating-current switch position, if be in a point position, and voltage on line side has at least a phase voltage to exceed threshold value, and continue for some time t, then open islanding detect condition, then judge whether connect alternating-current switch is changed to co-bit from a point position, as change just sets the current AC voltage-phase of locking by the phase-locked link of the control system of top level control device, start control mode conversion simultaneously, Active control mode is controlled transitions to by current flexible direct-current transmission system converter station isolated island.
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| CN201410811863.7A CN104578128B (en) | 2014-12-23 | 2014-12-23 | A kind of flexible direct current power transmission system isolated island turns the switching method of networking |
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Cited By (7)
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| CN105140948A (en) * | 2015-07-06 | 2015-12-09 | 南京南瑞继保电气有限公司 | Flexible direct current transmission system power coordination control method |
| CN105870967A (en) * | 2016-04-29 | 2016-08-17 | 许继电气股份有限公司 | Islanding-to-networking control method and system for flexible direct-current transmission system |
| CN106786592A (en) * | 2017-01-13 | 2017-05-31 | 全球能源互联网研究院 | A kind of isolated island method for handover control and device suitable for flexible direct current power transmission system |
| CN106953349A (en) * | 2017-04-27 | 2017-07-14 | 南京南瑞继保电气有限公司 | A kind of method started for flexible direct current power transmission system isolated island |
| CN108023337A (en) * | 2016-10-31 | 2018-05-11 | 南京南瑞继保电气有限公司 | A kind of flexible direct current power transmission system transverter operates in failure current limit control and protection fitting method under island state |
| CN111130141A (en) * | 2020-01-17 | 2020-05-08 | 中国电力科学研究院有限公司 | Switching controller for networking and island operation of flexible direct current converter station |
| CN112731014A (en) * | 2020-12-18 | 2021-04-30 | 佛山科学技术学院 | Island detection method and device for direct-current interconnected power distribution system |
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Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105140948A (en) * | 2015-07-06 | 2015-12-09 | 南京南瑞继保电气有限公司 | Flexible direct current transmission system power coordination control method |
| CN105870967A (en) * | 2016-04-29 | 2016-08-17 | 许继电气股份有限公司 | Islanding-to-networking control method and system for flexible direct-current transmission system |
| CN105870967B (en) * | 2016-04-29 | 2020-06-16 | 许继电气股份有限公司 | Island-to-network control method and system for flexible direct current transmission system |
| CN108023337B (en) * | 2016-10-31 | 2019-07-23 | 南京南瑞继保电气有限公司 | A kind of flexible HVDC transmission system inverter operates in failure current limit control and protection fitting method under island state |
| CN108023337A (en) * | 2016-10-31 | 2018-05-11 | 南京南瑞继保电气有限公司 | A kind of flexible direct current power transmission system transverter operates in failure current limit control and protection fitting method under island state |
| JP2019532611A (en) * | 2016-10-31 | 2019-11-07 | エヌアール エレクトリック カンパニー リミテッドＮｒ Ｅｌｅｃｔｒｉｃ Ｃｏ．， Ｌｔｄ | Fault current limit control and protection coordination method when the converter of flexible DC power transmission system operates in island mode |
| CN106786592A (en) * | 2017-01-13 | 2017-05-31 | 全球能源互联网研究院 | A kind of isolated island method for handover control and device suitable for flexible direct current power transmission system |
| CN106786592B (en) * | 2017-01-13 | 2023-01-24 | 全球能源互联网研究院有限公司 | Island switching control method and device suitable for flexible direct current transmission system |
| CN106953349B (en) * | 2017-04-27 | 2019-06-21 | 南京南瑞继保电气有限公司 | A method of start for flexible island direct current transmission system island |
| CN106953349A (en) * | 2017-04-27 | 2017-07-14 | 南京南瑞继保电气有限公司 | A kind of method started for flexible direct current power transmission system isolated island |
| US11329486B2 (en) | 2017-04-27 | 2022-05-10 | Nr Electric Co., Ltd | Method for initiating flexible DC transmission system under isolated island condition |
| CN111130141A (en) * | 2020-01-17 | 2020-05-08 | 中国电力科学研究院有限公司 | Switching controller for networking and island operation of flexible direct current converter station |
| CN112731014A (en) * | 2020-12-18 | 2021-04-30 | 佛山科学技术学院 | Island detection method and device for direct-current interconnected power distribution system |
| CN112731014B (en) * | 2020-12-18 | 2023-12-26 | 佛山科学技术学院 | Island detection method and device for direct-current interconnection power distribution system |
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