CN104659809A - Anti-islanding grid-connection intelligent switch protection method for distributed type power supply system and grid-connection intelligent switch device - Google Patents
Anti-islanding grid-connection intelligent switch protection method for distributed type power supply system and grid-connection intelligent switch device Download PDFInfo
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- CN104659809A CN104659809A CN201510037649.5A CN201510037649A CN104659809A CN 104659809 A CN104659809 A CN 104659809A CN 201510037649 A CN201510037649 A CN 201510037649A CN 104659809 A CN104659809 A CN 104659809A
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- inverter
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- voltage
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Classifications
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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
- H02J3/381—Dispersed generators
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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
- H02H7/267—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 parallel lines and wires
-
- 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
Abstract
The invention discloses an anti-islanding grid-connection intelligent switch protection method for a distributed type power supply system and a grid-connection intelligent switch device. The distributed type power supply system is converted into alternating current power through an inverter, and the alternating current power is converted into electric energy of the corresponding voltage level through a transformer and is connected into a power distribution network through a grid-connection switch; the grid-connection intelligent switch protection method comprises the following steps: injecting certain disturbance into the output power, the frequency or the phase of a grid-connection inverter by controlling the grid-connection inverter, and detecting the output situation of the inverter, wherein when a power grid works normally, a disturbance signal cannot change the output characteristic of the grid-connection inverter under the balance action of the power grid; when the power grid fails, the output characteristic of the grid-connection inverter can be quickly accumulated and exceed an allowable range under the feedback action of the disturbance signal; if the output current, the output voltage and the output power, detected by injection of the disturbance signal into the grid-connection inverter, of the grid-connection inverter exceed the allowable range, a signal is generated to trigger a protection device of the grid-connection switch immediately to enable the protection device to trip.
Description
Technical field
What the present invention relates to is a kind of grid-connected intelligent switch method and switching device of distributed power supply system isolated island effect prevention, belongs to power system security resist technology field.
Background technology
In prior art, when electrical network has a power failure because of fault or maintenance, distributed generation system (wind power generation, solar power generation) fails detect power down mode in time and self is cut off electrical network, and the self-energizing isolated island formed.
Isolated island is once produce the safety of maintenance personal and the public on entail dangers to power grid transmission line road; Affect the operation program of the protection switch in distribution system, impact electric network protection device; Affect electric energy transmitting quality, the supply power voltage in electric power isolated island region and frequency are by instability; The phase place that can cause after mains supply recovers is asynchronous; Single-phase distributed generation system can cause system threephase load loss phase to power, and therefore must can carry out anti-islanding effect detection for a Grid-connected Distributed Generation Power System, and can cut off electrical network in time.
Summary of the invention
The object of the invention is to the deficiency overcoming prior art existence; and provide a kind of method simple and reliable; strick precaution island effect produces, and improves grid-connected power supply effect, ensures the grid-connected switch protection method of the distributed power supply system isolated island effect prevention of electric power system safety and grid-connected switching device.
The object of the invention is to have come by following technical solution; a kind of grid-connected intelligent switch guard method of distributed power supply system isolated island effect prevention; the direct current power that described distributed power supply system comprises wind energy, solar energy exports; AC power is converted to by inverter; converted to the electric energy of relevant voltage grade again by transformer; and be incorporated to power distribution network by grid-connected switch, described grid-connected intelligent switch guard method is:
By controlling combining inverter, injecting certain disturbance, comprise current disturbing method, i.e. motional impedance mensuration to its power output, frequency or phase place etc., frequency shift (FS), sudden change method, voltage shift method, detects the output situation of inverter simultaneously; When electrical network normally works, due to the balanced action of electrical network, disturbing signal is not enough to the output characteristic changing combining inverter; When electric network fault or power down, due to the feedback effect of disturbing signal, the output characteristic of combining inverter will accelerated accumulation and exceed allowed band, thus achieves fast detecting; As when inject to combining inverter disturbing signal detecting to combining inverter output current, voltage, power exceed allowed band, produce a signal, and horse back triggers the protective device of grid-connected switch, makes its isolation electrical network that trips;
After switch trip, be checked through voltage in bus rated voltage at its more than 88%UN by the voltage transformer pt installed on the bus of power distribution network, give grid-connected intelligent switch by triggering signal, make it close a floodgate.
A kind of grid-connected intelligent switch device of the grid-connected intelligent switch guard method for above-mentioned distributed power supply system isolated island effect prevention, it comprises one and is connected to distributed power supply system, the direct current power that distributed power supply system exports can be converted to the inverter of AC power, described inverter connects the transformer that alternating voltage can be converted to relevant voltage grade electric energy by, described transformer passes behind a grid-connected switch and accesses power distribution network, described combining inverter is one in its power output, frequency or phase place inject certain disturbance direct current and exports the inverter of a variable AC current, the detection ammeter of a setting current value is in series with at the output of combining inverter, described detection ammeter is connected to can be triggered and the grid-connected switch of tripping operation by the electric network fault of the generation of secondary circuit or power-off signal by the secondary circuit connected,
The bus L of power distribution network is in series with the voltage transformer that can detect bus rated voltage, on this voltage transformer, setting voltage value is the 88%UN of load voltage value, and on this voltage transformer pt, be checked through voltage in bus rated voltage at its more than 88%UN, just can produce triggering signal to the grid-connected intelligent switch be connected, make it close a floodgate.
Combining inverter of the present invention is one inject disturbance direct current the inverter of output AC electric current by power supply to inverter, after inverter, current value is obtained in detection ammeter thereafter, when gained current value exceedes set point, the secondary circuit be connected with detection ammeter produces triggering signal and is sent to connected grid-connected switch, and by grid-connected switch generation trip operation;
Described voltage transformer is after switch trip, and by being checked through voltage in bus rated voltage after its more than 88%UN, triggering signal gives the grid-connected intelligent switch be connected, and makes it close a floodgate.
The present invention improves the one of prior art, and it is simple and reliable that it has method, takes precautions against island effect and produces, possess auto-reset function, can improve the reliability of electrical network, improve grid-connected power supply effect, ensures the electric power system feature such as safely.
Accompanying drawing explanation
Fig. 1 is structure theory of constitution figure of the present invention.
Embodiment
Below in conjunction with accompanying drawing, the present invention will be described in detail: a kind of grid-connected intelligent switch guard method of distributed power supply system isolated island effect prevention; the direct current power that described distributed power supply system comprises wind energy, solar energy exports; AC power is converted to by inverter; converted to the electric energy of relevant voltage grade again by transformer; and be incorporated to power distribution network by grid-connected switch DK, described grid-connected intelligent switch guard method is:
By controlling combining inverter, injecting certain disturbance, comprise current disturbing method, i.e. motional impedance mensuration to its power output, frequency or phase place etc., frequency shift (FS), sudden change method, voltage shift method, detects the output situation of inverter simultaneously; When electrical network normally works, due to the balanced action of electrical network, disturbing signal is not enough to the output characteristic changing combining inverter; When electric network fault or power down, due to the feedback effect of disturbing signal, the output characteristic of combining inverter will accelerated accumulation and exceed allowed band, thus achieves fast detecting; As when inject to combining inverter disturbing signal detecting to combining inverter output current, voltage, power exceed allowed band, produce a signal, and horse back triggers the protective device of grid-connected switch DK, makes its isolation electrical network that trips;
After switch trip, be checked through voltage in bus L rated voltage at its more than 88%UN by the voltage transformer pt installed on the bus L of power distribution network, give grid-connected intelligent switch DK by triggering signal, make it close a floodgate.
A kind of grid-connected intelligent switch device of the grid-connected intelligent switch guard method for above-mentioned distributed power supply system isolated island effect prevention, it comprises one and is connected to distributed power supply system, the direct current power that distributed power supply system exports can be converted to the inverter of AC power, described inverter connects the transformer that alternating voltage can be converted to relevant voltage grade electric energy by, described transformer passes behind a grid-connected switch and accesses power distribution network, described combining inverter is one in its power output, frequency or phase place inject certain disturbance direct current and exports the inverter of a variable AC current, the detection ammeter of a setting current value is in series with at the output of combining inverter, described detection ammeter is connected to can be triggered and the grid-connected switch of tripping operation by the electric network fault of the generation of secondary circuit or power-off signal by the secondary circuit connected,
The bus L of power distribution network is in series with the voltage transformer pt that can detect bus L rated voltage, on this voltage transformer pt, setting voltage value is the 88%UN of load voltage value, and on this voltage transformer pt, be checked through voltage in bus L rated voltage at its more than 88%UN, just can produce triggering signal to the grid-connected intelligent switch DK be connected, make it close a floodgate.
Combining inverter of the present invention is one inject disturbance direct current I1 the inverter of output AC electric current by power supply T1 to inverter, after inverter, current value is obtained in detection ammeter thereafter, when gained current value exceedes set point, the secondary circuit be connected with detection ammeter produces triggering signal and is sent to connected grid-connected switch, and by grid-connected switch generation trip operation;
Described voltage transformer pt is after switch trip, and by being checked through voltage in bus L rated voltage after its more than 88%UN, triggering signal gives the grid-connected intelligent switch DK be connected, and makes it close a floodgate.
Embodiment: shown in Fig. 1, distributed power supply system of the present invention, comprises the direct current power of wind energy, solar energy output, AC power is converted to by inverter, converted to the electric energy of relevant voltage grade again by transformer, be incorporated to power distribution network, grid-connected have special grid-connected switch DK; For preventing the generation of isolated island benefit, by controlling combining inverter, inject certain disturbance to its power output, frequency or phase place etc., as current disturbing method (motional impedance mensuration), frequency shift (FS), sudden change method, voltage shift method, detects the output situation of inverter simultaneously.When electrical network normally works, due to the balanced action of electrical network, disturbing signal is not enough to the output characteristic changing combining inverter; When electric network fault or power down, due to the feedback effect of disturbing signal, the output characteristic of combining inverter will accelerated accumulation and exceed allowed band, thus achieves fast detecting; As when injecting disturbing signal to combining inverter, detect combining inverter output current, voltage, power exceed allowed band, produce a signal; and trigger the protective device of grid-connected switch DK at once; make it trip, make it isolate electrical network, improve electric network security, reliability.
As injected disturbance direct current I1 by power supply T1 to inverter; after inverter; the alternating current exported obtains I2 by ammeter, if set point is 20A, when I2 is more than 20A; a signal is produced by secondary circuit; pass to grid-connected switch DK, and trigger the protective device of grid-connected switch DK at once, make it trip; make it isolate electrical network, improve electric network security, reliability.
After switch trip, if be checked through voltage in bus L rated voltage at its more than 88%UN by the voltage transformer pt on bus L, by triggering signal to DK, make it close a floodgate, possess auto-reset function, improve the reliability of electrical network.
Claims (3)
1. the grid-connected intelligent switch guard method of a distributed power supply system isolated island effect prevention; the direct current power that described distributed power supply system comprises wind energy, solar energy exports; AC power is converted to by inverter; converted to the electric energy of relevant voltage grade again by transformer; and be incorporated to power distribution network by grid-connected switch, it is characterized in that grid-connected intelligent switch guard method is:
By controlling combining inverter, injecting certain disturbance, comprise current disturbing method, i.e. motional impedance mensuration to its power output, frequency or phase place etc., frequency shift (FS), sudden change method, voltage shift method, detects the output situation of inverter simultaneously; When electrical network normally works, due to the balanced action of electrical network, disturbing signal is not enough to the output characteristic changing combining inverter; When electric network fault or power down, due to the feedback effect of disturbing signal, the output characteristic of combining inverter will accelerated accumulation and exceed allowed band, thus achieves fast detecting; As when inject to combining inverter disturbing signal detecting to combining inverter output current, voltage, power exceed allowed band, produce a signal, and horse back triggers the protective device of grid-connected switch, makes its isolation electrical network that trips;
After switch trip, be checked through voltage in bus rated voltage at its more than 88%UN by the voltage transformer pt installed on the bus of power distribution network, give grid-connected intelligent switch by triggering signal, make it close a floodgate.
2. the grid-connected intelligent switch device for the grid-connected intelligent switch guard method of distributed power supply system isolated island effect prevention described in claim 1, it comprises one and is connected to distributed power supply system, the direct current power that distributed power supply system exports can be converted to the inverter of AC power, described inverter connects the transformer that alternating voltage can be converted to relevant voltage grade electric energy by, described transformer passes behind a grid-connected switch and accesses power distribution network, it is characterized in that described combining inverter is one in its power output, frequency or phase place inject certain disturbance direct current and exports the inverter of a variable AC current, the detection ammeter of a setting current value is in series with at the output of combining inverter, described detection ammeter is connected to can be triggered and the grid-connected switch of tripping operation by the electric network fault of the generation of secondary circuit or power-off signal by the secondary circuit connected,
The bus of power distribution network is in series with the voltage transformer that can detect bus rated voltage, on this voltage transformer, setting voltage value is the 88%UN of load voltage value, and on this voltage transformer, be checked through voltage in bus rated voltage at its more than 88%UN, just can produce triggering signal to the grid-connected intelligent switch be connected, make it close a floodgate.
3. grid-connected switching device according to claim 2, it is characterized in that described combining inverter is one inject disturbance direct current the inverter of output AC electric current by power supply to inverter, after inverter, current value is obtained in detection ammeter thereafter, when gained current value exceedes set point, the secondary circuit be connected with detection ammeter produces triggering signal and is sent to connected grid-connected switch, and by grid-connected switch generation trip operation;
Described voltage transformer is after switch trip, and by being checked through voltage in bus rated voltage after its more than 88%UN, triggering signal gives the grid-connected intelligent switch be connected, and makes it close a floodgate.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105305483A (en) * | 2015-09-30 | 2016-02-03 | 华北电力大学 | Inverter grid connected type power source impedance measurement model optimization method under the condition of external disturbance signals |
| CN106602599A (en) * | 2016-12-21 | 2017-04-26 | 天津瑞能电气有限公司 | Passive type island crossing method based on wind generator system |
| CN108469570A (en) * | 2018-02-05 | 2018-08-31 | 全球能源互联网研究院有限公司 | A kind of electric network fault processing method and system based on inverter |
| CN108988392A (en) * | 2018-08-17 | 2018-12-11 | 国网山西省电力公司大同供电公司 | A kind of power distribution network self-adaptive low-voltage anti-island method based on back-to-back converter |
| CN112180313A (en) * | 2020-09-02 | 2021-01-05 | 深圳市首航新能源股份有限公司 | Automatic correction method and control device for current transformer and energy storage equipment |
| CN112491015A (en) * | 2020-11-10 | 2021-03-12 | 深圳供电局有限公司 | Time synchronization method suitable for power distribution network |
| CN108988392B (en) * | 2018-08-17 | 2024-04-19 | 国网山西省电力公司大同供电公司 | Power distribution network self-adaptive low-voltage anti-island method based on back-to-back converter |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105305483A (en) * | 2015-09-30 | 2016-02-03 | 华北电力大学 | Inverter grid connected type power source impedance measurement model optimization method under the condition of external disturbance signals |
| CN105305483B (en) * | 2015-09-30 | 2017-08-04 | 华北电力大学 | Grid-connected inverters class power measurement impedance model optimization method under external disturbance signal |
| CN106602599A (en) * | 2016-12-21 | 2017-04-26 | 天津瑞能电气有限公司 | Passive type island crossing method based on wind generator system |
| CN106602599B (en) * | 2016-12-21 | 2019-03-01 | 天津瑞能电气有限公司 | A kind of passive type isolated island traversing method based on wind generator system |
| CN108469570A (en) * | 2018-02-05 | 2018-08-31 | 全球能源互联网研究院有限公司 | A kind of electric network fault processing method and system based on inverter |
| CN108469570B (en) * | 2018-02-05 | 2020-08-04 | 全球能源互联网研究院有限公司 | Power grid fault processing method and system based on inverter |
| CN108988392A (en) * | 2018-08-17 | 2018-12-11 | 国网山西省电力公司大同供电公司 | A kind of power distribution network self-adaptive low-voltage anti-island method based on back-to-back converter |
| CN108988392B (en) * | 2018-08-17 | 2024-04-19 | 国网山西省电力公司大同供电公司 | Power distribution network self-adaptive low-voltage anti-island method based on back-to-back converter |
| CN112180313A (en) * | 2020-09-02 | 2021-01-05 | 深圳市首航新能源股份有限公司 | Automatic correction method and control device for current transformer and energy storage equipment |
| CN112180313B (en) * | 2020-09-02 | 2023-11-10 | 深圳市首航新能源股份有限公司 | Automatic correction method, control device and energy storage equipment for current transformer |
| CN112491015A (en) * | 2020-11-10 | 2021-03-12 | 深圳供电局有限公司 | Time synchronization method suitable for power distribution network |
| CN112491015B (en) * | 2020-11-10 | 2022-12-13 | 深圳供电局有限公司 | Time synchronization method suitable for power distribution network |
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Application publication date: 20150527 |