CN108011359B - A kind of isolated island protective device and its detection algorithm for distributed generation resource - Google Patents
A kind of isolated island protective device and its detection algorithm for distributed generation resource Download PDFInfo
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- CN108011359B CN108011359B CN201711361142.0A CN201711361142A CN108011359B CN 108011359 B CN108011359 B CN 108011359B CN 201711361142 A CN201711361142 A CN 201711361142A CN 108011359 B CN108011359 B CN 108011359B
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- isolated island
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- distributed generation
- thyristor
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
-
- 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
- H02H7/261—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 involving signal transmission between at least two stations
- H02H7/262—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 involving signal transmission between at least two stations involving transmissions of switching or blocking orders
-
- 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
- H02H7/261—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 involving signal transmission between at least two stations
- H02H7/263—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 involving signal transmission between at least two stations involving transmissions of measured values
-
- 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
- H02J3/381—Dispersed generators
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention discloses a kind of isolated island protective devices for distributed generation resource, including step-down transformer, current-limiting reactor, thyristor and controller unit.The present invention manufactures a controlled short circuit current and network voltage distortion by certain section internal trigger turn on thyristors near network voltage zero passage；The invention also discloses the detection algorithm of such isolated island protective device, detection algorithm includes IGBT group angle on-line optimization algorithm and isolated island criterion algorithm.The notable difference with the capacity of short circuit of distributed power access point when being detached from is supported based on power grid, and the present invention can go out whether distributed generation resource is in isolated operation with reliable recognition.The isolated island protective device of the invention be it is a kind of can distributed installation equipment, do not depend on any medium of communication, at low cost, no signal decaying and interference problem.
Description
Technical field
The present invention relates to a kind of isolated island protective device technologies for distributed generation resource, belong to distributed power generation protection technique
Field.
Background technique
Distributed power generation source, such as the power generation of photovoltaic plant, wind power plant, miniature turbine, it is a large amount of to access mesohigh power grid,
But there is the risk disconnected with bulk power grid substation in transmission line, it is possible to forming the isolated operation of distributed generation resource.It is lonely
The safety that the distributed generation resource of island operation will jeopardize power grid testing staff, be powered load equipment and distributed generation resource itself, state
Border, domestic Grid-connection standards require the distributed generation resource of isolated operation that must reliably detect island state within a limited period of time and pacify
It is detached from entirely in points of common connection and power grid.
The isolated island protection scheme of distributed generation resource is generally divided into active, passive-type and communication type etc..Wherein actively disturb
Type isolated island detection algorithm is generally used for the distributed generation resource of access low-voltage network, and is realized based on gird-connected inverter and actively disturbed
It is dynamic；Passive-type island detection method is generally fairly simple, easy to accomplish, but there are biggish non-detection areas；The inspection of communication type isolated island
Survey method is widely used in the distributed power supply system of access mesohigh power grid, but this method needs to build connection upstream substation
With the communication line of distributed generation resource, there are high construction costs and dimension for most of foundation are in distributed generation resource from far-off regions
Protect difficult problem.In addition, the island detection method based on dedicated telephone line cannot effectively identify upstream substation and distribution
The scene that route disconnects between power supply.Existing bibliography proposes that the island detection method based on electric line carrier communication can be examined
The scene that transmission line of electricity disconnects is surveyed, but the receiving side there are detection signal transmitted by transformer substation side in distributed generation resource exists substantially
The problem for decaying and being disturbed increases malfunction and misaction rate.
If a kind of distributed isolated island protective device can be invented, equipment property right can be most important independently of distributed generation resource quotient
Be to avoid above-mentioned technology and cost disadvantage, safety, low operating cost and the low-maintenance cost of distributed generation resource will be greatly improved
Operation.
Summary of the invention
Technical problem: the present invention is used to solve isolated island protection when distributed generation resource access mesohigh power grid, to solve mesh
It is preceding to realize the existing problems such as the construction period is long, at high cost, reliability is low of isolated island protection based on communication modes.
Technical solution: the invention adopts the following technical scheme:
A kind of isolated island protective device for distributed generation resource, including step-down transformer (1), current-limiting reactor (2), thyristor
(3) and controller unit (4)；The former vice-side winding of step-down transformer (1) can be triangle or any combination of star-like connection；
Current-limiting reactor (2) can be independent inductance, or the leakage inductance of step-down transformer (1) is realized；Thyristor (3) is commercialization
Switching device can be single device, can also be combined in series and parallel and be obtained by multiple devices；Controller unit (4) includes voltage, electric current
Detection part, detection algorithm running unit, thyristor driver signal generator divide and protection signal generator point.
Further, the high-pressure side X of the step-down transformer is connected to the downstream of distributed generation resource feeder line breaker,
One end of low-pressure side connection current-limiting reactor.
Further, the anode of other end connection thyristor of the current-limiting reactor, the cathode of thyristor return to decompression and become
The low-pressure side of depressor, the gate pole of thyristor connect the Trigger Angle signal end of controller.
Further, the controller connection X point voltage measurement signal and T point current measurement signal.
Further, the protection signal end of the controller is connected to circuit-breaker, to execute isolated island trip protection
Operation.
A kind of detection algorithm of the isolated island protective device for distributed generation resource, detailed process is as follows:
The first step calculates time domain indexWherein Ipeak_Bef.It is networking shape
Thyristor current flows peak value, I under statepeak_Aft.It is the thyristor current flows peak value under island state；
Second calculating frequency-domain index Δ THD=THDAft.-THDBef., wherein THDBef.It is the public company under networking state
Junction voltage total harmonic distortion (THD) value, THDAft.It is the points of common connection voltage THD value under island state；
It is to meet that isolated island, which detects criterion,When, isolated island occurs.
Further, detailed process is as follows for the on-line optimization process at IGBT group angle:
Initialization definitions predeterminated voltage loses k, minimum trigger angle δ nmin and maximum Trigger Angle δ nmax, then according to isolated island
Protective device is connected across the difference of line voltage or phase voltage, and capacity of short circuit and predeterminated voltage loss k based on access point calculate just
Beginning Trigger Angle δ n；
Phase voltage form is connected:
Line voltage form is connected:
Whether within a preset range initial trigger angle δ n is checked, if otherwise carrying out clipping；
It checks thyristor current flows stress, and adjusts Trigger Angle；
The loss of voltage percentage of points of common connection is calculated, and adjusts Trigger Angle；
The voltage harmonic content of points of common connection is calculated, and adjusts Trigger Angle；
Export the real-time optimization Trigger Angle under current electric grid state.
The utility model has the advantages that the present invention is compared with prior art:
The present invention by the public access point in distributed generation resource be incorporated to step-down transformer, current-limiting inductance and thyristor groups at
Controllable short circuit current, access power grid in network voltage zero passage.Thus by points of common connection under networking and off-grid state
The different of capacity of short circuit will generate different short circuit current size and Voltage Harmonic level, and the present invention is based on time domains and frequency domain
Index can reliably determine whether isolated island occurs.The present invention realizes the local excitation local detection of isolated island detection, significantly reduces
System cost and the reliability for improving detection.
Detailed description of the invention
The circuit connecting mode schematic diagram of Fig. 1 isolated island protective device of the present invention when being for single distributed generation resource scene；
Fig. 2 is isolated island protection circuit key job waveform of the present invention and control timing diagram；
Fig. 3 is the present invention when isolated island protective device is connected across phase voltage channel under single distributed generation resource scene before isolated island
Key job waveform diagram afterwards；
Fig. 4 is the present invention when isolated island protective device is connected across line voltage channel under single distributed generation resource scene before isolated island
Key job waveform diagram afterwards；
Fig. 5 describes the circuit connecting mode schematic diagram that the present invention is used for the more distributed generation resource scenes of unit feeder；
Fig. 6 is that present invention isolated island protective device 1 under more 2 scenes of distributed generation resource embodiment of unit feeder is connected across phase voltage
Key job waveform diagram when channel before and after isolated island；
Fig. 7 is that present invention isolated island protective device under more 2 scenes of distributed generation resource embodiment of unit feeder is connected across phase voltage
Key job waveform diagram when channel before and after isolated island；
Fig. 8 is that present invention isolated island protective device 2 under more 2 scenes of distributed generation resource embodiment of unit feeder is connected across phase voltage
Points of common connection voltage waveform and low-order harmonic distribution map before isolated island when channel；
Fig. 9 is that present invention isolated island protective device 2 under more 2 scenes of distributed generation resource embodiment of unit feeder is connected across phase voltage
Points of common connection voltage waveform and low-order harmonic distribution map after isolated island when channel；
Figure 10 is online Trigger Angle optimized flow chart of the invention.
Specific embodiment
Isolated island protective device of the invention is installed as shown in Figure 1, accessing out by the common point in distributed generation resource, is passed through
Real-time detection voltage zero-crossing point of power grid and real-time online optimize IGBT group angle, and periodically, by phased manner with rotation ground
Triggering short-circuit loop carries out island state identification by isolated island criterion to obtain time domain and frequency domain detection index.
Embodiment 1:
Fig. 1 describes circuit connecting mode of the embodiment of the present invention 1 for single distributed generation resource scene, step-down transformer
High-pressure side X be connected to the downstream of distributed generation resource feeder line breaker, low-pressure side connects one end of current-limiting reactor；Current limliting electricity
The anode of anti-other end connection thyristor, the cathode of thyristor return to the low-pressure side neutral point of step-down transformer, thyristor
The Trigger Angle signal end of gate pole connection controller；Controller connects X point voltage measurement signal and T point current measurement signal；Control
The protection signal end connection circuit-breaker of device executes the operation of isolated island trip protection.
Fig. 2 is the isolated island protection circuit key job waveform and control sequential of the embodiment of the present invention 1.Isolated island protective device control
Device processed δ angle triggering thyristor before voltage zero-crossing point of power grid forms the short circuit to current-limiting inductance, so that on inductive current is quick
Reach peak I when rising to network voltage zero pointpeak, subsequent inductive current under network voltage effect rapid decrease until be zero,
Entire detection operation is completed.It can be seen that the part that detection operation causes points of common connection voltage from test point X voltage waveform
Loss.
Fig. 3 is the key that when isolated island protective device is connected across phase voltage channel under 1 scene of the embodiment of the present invention before and after isolated island
Working waveform figure；Fig. 4 is pass when isolated island protective device is connected across line voltage channel under 1 scene of the embodiment of the present invention before and after isolated island
Key working waveform figure.Under two kinds of connection types, peak value of short shows apparent difference before and after isolated island, when only relying on
Domain index Δ IpeakIsland state can be identified.
Embodiment 2:
Fig. 5 describes circuit connecting mode of the embodiment of the present invention 2 for the more distributed generation resource scenes of unit feeder, in route
2. distributed generation resource 1 accesses the node of M1, and isolated island protective device 1 of the invention is connected to line attachment breaker and distributed electrical
Between source 1；Isolated island protective device 2 is connected between line attachment breaker and distributed generation resource 2.
Fig. 6 is the key that when isolated island protective device 1 is connected across phase voltage channel under 2 scene of the embodiment of the present invention before and after isolated island
Working waveform figure；Fig. 7 is pass when isolated island protective device is connected across phase voltage channel under 2 scene of the embodiment of the present invention before and after isolated island
Key working waveform figure.After isolated island occurs, the peak value of short of isolated island protective device 1 has reduction, but isolated island protective device 2 is short
Current peak reduction in road is unobvious, and after the disengagement of distributed generation resource 1, the short circuit current of isolated island protective device 2 is had occurred obviously
Variation.Therefore, single time domain index Δ IpeakDifferentiate that the island state under more distributed generation resource scenes has delay.
Fig. 8 is commonly connected before isolated island when isolated island protective device 2 is connected across phase voltage channel under 2 scene of the embodiment of the present invention
Point voltage waveform and low-order harmonic distribution map；Fig. 9 is that isolated island protective device 2 is connected across phase voltage under 2 scene of the embodiment of the present invention
Points of common connection voltage waveform and low-order harmonic distribution map after isolated island when channel.Frequency-domain index Δ THD is explicitly indicated before and after isolated island
The generation of island state, therefore, based on time-domain and frequency-domain combined index more distributed generation resource scenes be it is a kind of in time, efficiently, it is quasi-
Standby isolated island method of discrimination.
Two kinds of embodiments of the invention are described in detail above, still, during present invention is not limited to the embodiments described above
Detail a variety of equivalents can be carried out to technical solution of the present invention within the scope of the technical concept of the present invention, this
A little equivalents all belong to the scope of protection of the present invention.
It is further to note that specific technical features described in the above specific embodiments, in not lance
In the case where shield, it can be combined in any appropriate way.In order to avoid unnecessary repetition, the present invention to it is various can
No further explanation will be given for the combination of energy.In addition, any group can also be carried out between a variety of different embodiments of the invention
It closes, as long as it does not violate the idea of the present invention, it should also be regarded as the disclosure of the present invention.
Claims (1)
1. a kind of detection algorithm of the isolated island protective device for distributed generation resource, it is characterised in that: isolated island protective device includes
Step-down transformer (1), current-limiting reactor (2), thyristor (3) and controller unit (4)；The former vice-side winding of step-down transformer (1)
It can be triangle or any combination of star-like connection；Current-limiting reactor (2) can be independent inductance, or downconverter
The leakage inductance of device (1) is realized；Thyristor (3) is commercial switching device, can be single device, can also be series-parallel group by multiple devices
Conjunction obtains；Controller unit (4) includes voltage, current detecting part, detection algorithm running unit, the generation of thyristor driver signal
Part and protection signal generator point；
The first step calculates time domain indexWherein Ipeak_Bef.It is under networking state
Thyristor current flows peak value, Ipeak_Aft.It is the thyristor current flows peak value under island state；
Second step calculates frequency-domain index Δ THD=THDAft.-THDBef., wherein THDBef.It is the points of common connection under networking state
Voltage total harmonic distortion (THD) value, THDAft.It is the points of common connection voltage THD value under island state；
It is to meet that isolated island, which detects criterion,When, isolated island occurs；
Detailed process is as follows for the on-line optimization process at IGBT group angle:
Initialization definitions predeterminated voltage loses k, minimum trigger angle δ nmin and maximum Trigger Angle δ nmax, is then protected according to isolated island
Device is connected across the difference of line voltage or phase voltage, and capacity of short circuit and predeterminated voltage loss k based on access point calculate initial touching
Send out angle δ n；
Phase voltage form is connected:
Wherein SPG_feederIt is X point phase voltage shorted to earth capacity, SPN_DGIt is distributed generation resource phase voltage shorted to earth capacity, ST
It is step-down transformer capacity, xTIt is the short-circuit impedance percentage of step-down transformer；
Line voltage form is connected:
Wherein S3ph_feederIt is X point three-phase symmetrical capacity of short circuit, S3ph_DGIt is distributed generation resource three-phase symmetrical capacity of short circuit；
Whether within a preset range initial trigger angle δ n is checked, if otherwise carrying out clipping；
It checks thyristor current flows stress, reduces Trigger Angle if thyristor stress does not transfinite；
The loss of voltage percentage for calculating points of common connection, if the loss of voltage of points of common connection is less than or equal to one percentage point
Increase Trigger Angle；
The voltage harmonic content for calculating points of common connection, if the voltage harmonic content of points of common connection is more than or equal to 5 percent
Reduce Trigger Angle；
Export the real-time optimization Trigger Angle under current electric grid state.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711361142.0A CN108011359B (en) | 2017-12-18 | 2017-12-18 | A kind of isolated island protective device and its detection algorithm for distributed generation resource |
| PCT/CN2018/110585 WO2019119947A1 (en) | 2017-12-18 | 2018-10-17 | Islanding protection device for distributed power supply and detection algorithm thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711361142.0A CN108011359B (en) | 2017-12-18 | 2017-12-18 | A kind of isolated island protective device and its detection algorithm for distributed generation resource |
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| CN108011359A CN108011359A (en) | 2018-05-08 |
| CN108011359B true CN108011359B (en) | 2019-08-20 |
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| CN108011359B (en) * | 2017-12-18 | 2019-08-20 | 东南大学 | A kind of isolated island protective device and its detection algorithm for distributed generation resource |
| CN113964801B (en) * | 2021-10-13 | 2024-06-18 | 南京南瑞继保电气有限公司 | Distance protection optimization method and device for high-voltage line protection device |
| CN113991598B (en) * | 2021-11-29 | 2023-08-08 | 深圳供电局有限公司 | Three-phase reclosing method of inversion type distributed power supply |
| CN114336541B (en) * | 2021-12-01 | 2023-07-28 | 国网辽宁省电力有限公司锦州供电公司 | Island protection configuration prevention method for different voltage classes |
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| CN102185335A (en) * | 2011-05-05 | 2011-09-14 | 山东电力研究院 | Novel island detection method and system |
| CN105024403B (en) * | 2015-07-24 | 2018-01-09 | 国网天津市电力公司 | A kind of micro-capacitance sensor isolated island and grid-connected whistle control system and method |
| CN106443501B (en) * | 2016-10-27 | 2017-10-20 | 广东电网有限责任公司茂名供电局 | Distributed generator islanding detection method and system |
| CN107294128B (en) * | 2017-06-01 | 2020-04-21 | 南京南瑞继保电气有限公司 | Distributed power supply comprehensive anti-islanding protection system and method |
| CN108011359B (en) * | 2017-12-18 | 2019-08-20 | 东南大学 | A kind of isolated island protective device and its detection algorithm for distributed generation resource |
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| CN108011359A (en) | 2018-05-08 |
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