CN104950202A - Island detection method and system based on reactive power-frequency positive feedback - Google Patents
Island detection method and system based on reactive power-frequency positive feedback Download PDFInfo
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Abstract
The invention provides an island detection method based on reactive power-frequency positive feedback. The detection method comprises the steps of collecting network voltage first, obtaining a frequency f through a phase-locked loop, then obtaining delta f through a band-pass filter, then multiplying the delta f by gains, so as to obtain the reactive current disturbance quantity delta i through a limiter, and adding the disturbance quantity to given reactive current at last. When a power network is off and frequency increase is detected by an inverter, the given q-axis current of the inverter can be increased under the action of positive feedback, so that reactive power output by the inverter can be increased. The frequency can be further increased according to reactive power-frequency characteristics of loads. The reactive power of the inverter is further increased by the increased frequency, the final frequency can exceed a normal working area, and a passive island detection method is matched, so as to detect an island state at last. A non-detection area does not exist in the island detection method, and the influence on the quality of electric energy is less because artificially introduced current disturbance does not exist.
Description
Technical field
The present invention relates to the islanding detect technology in combining inverter field, be specifically related to a kind of island detection method based on idle-frequency positive feedback and system.
Background technology
Along with going from bad to worse of global environment, generation of electricity by new energy technology is subject to people and more and more pays close attention to, and combining inverter have also been obtained as the device of energy exchange between regenerative resource and electrical network and applies widely.In the distributed generation system or micro-grid system of regenerative resource, combining inverter and electrical network composition, jointly powered to the load by combining inverter and electrical network.When grid collapses disconnects, load is powered separately by combining inverter, and system will depart from electrical network and continue to run, and forms isolated island.Island effect make voltage and frequency out of hand, will there is larger fluctuation in the voltage in islanded system and frequency, thus cause damage to electrical network and subscriber equipment; The circuit that island effect makes some be considered to disconnect with all power supplys is charged, and this can bring the danger of electric shock to electrical network maintenance personal and user.Therefore, combining inverter must possess a kind of reliable and effective island detection method.
At present, conventional island detection method is divided into passive type islanding detect method and active alone island detection method.
What passive type islanding detect method was conventional is detect voltage magnitude and frequency, can detect island state when voltage magnitude or frequency cross the protection threshold value of setting.But when the meritorious and reactive power that inverter provides and loading demand only have slight mismatch to mate even completely time, voltage magnitude and frequency offset are difficult to the protection threshold value of crossing setting, and islanding detect will be failed, have larger check frequency.
What active alone island detection method was conventional is active frequency drift method, principle is that combining inverter passes through to inject to electrical network the electric current having a distortion a little, after suspension, the trend changed up or down is continuously formed to make the frequency of inverter output end voltage, final frequency skew exceedes setting threshold value, then island state is detected.Disturbance added by active frequency drift method makes current waveform distort, and can affect the output quality of power supply of combining inverter; In addition for upwards shift frequency method, if load is capacitance-resistance, then may cause islanding detect failure.
Summary of the invention
For the problems referred to above, the invention provides that a kind of to export quality of power supply impact to inverter little, and without the island detection method of check frequency and system.
The technical scheme that the present invention adopts for its technical matters of solution is:
Based on an island detection method for idle-frequency positive feedback, it is characterized in that comprising the following steps:
Step 1, reads grid-connected point voltage in each sampling period;
Step 2, obtains frequency f by grid-connected point voltage through phaselocked loop;
Step 3, judges whether grid-connected point voltage frequency f is greater than overfrequency or is less than underfrequency protection threshold value, if so, then detects island state, shuts down, and disconnects the connection with electrical network; If no, enter step 4;
Step 4, obtains pass band width Δ f by grid-connected point voltage frequency through bandpass filter, and pass band width Δ f is multiplied by proportional gain factor, and the value obtained obtains reactive current disturbance quantity Δ i by amplitude limit, reactive current disturbance quantity Δ i is added in reactive current given on;
Step 5, according to load idle-frequency characteristic:
，
During grid cut-off, the frequency that inverter detects increases, positive feedback effect can make the given increase of inverter q shaft current, the reactive power that inverter exports can be increased like this, thus frequency can increase further, the frequency of increase increases the reactive power of inverter further, and final frequency can exceed normal range of operation, coordinate passive island detection method, finally detect island state.
As the further improvement of such scheme, the phaselocked loop in described step 2 is reference synchronization coordinate system phaselocked loop.
Further, described over frequency protection threshold value is 50.2Hz, and underfrequency protection threshold value is 47.2Hz.
Based on an alone island detection system for idle-frequency positive feedback, comprise combining inverter, load and electrical network, characterized by further comprising:
Electric current, voltage acquisition unit, be respectively used to the output three-phase current (i gathering combining inverter
a, i
b, i
c) and and site three-phase voltage (u
a, u
b, u
c);
Electric current, voltage abc-dq phase coordinates transducer, be respectively used to three-phase current, voltage (i
a, i
b, i
c), (u
a, u
b, u
c) convert rotatory current, voltage (i to
d, i
q), (u
dand u
q);
Phase-locked loop pll, is connected with voltage abc-dq phase coordinates transducer, and for calculating phase-locked angle q and frequency f, wherein phase-locked angle qq is used for participating in the coordinate transform between electric current, voltage abc-dq phase coordinates transducer;
Bandpass filter, is connected with phase-locked loop pll, for calculating pass band width Δ f;
Gain module, amplifies for pass band width Δ f being multiplied by gain;
Limiter, is connected with gain module, for obtaining reactive current disturbance quantity Δ i by being multiplied by the Δ f value after gain through amplitude limit;
D axis scale integral controller, for by actual current d axle component i
dwith d shaft current specified rate i
d *error amount after comparing carries out integral transformation, obtains d axle controlled quentity controlled variable;
Q axis scale integral controller, for by actual current q axle component i
qwith q shaft current specified rate i
q *add the value of reactive current disturbance quantity Δ i compare after error amount carry out integral transformation, obtain q axle controlled quentity controlled variable;
Dq-α β coordinate converter, for converting the controlled quentity controlled variable under α β axle to by d axle, q axle controlled quentity controlled variable;
SVPWM modulator, for obtaining the break-make of each brachium pontis of PWM ripple control inverter by SVPWM modulation algorithm by the controlled quentity controlled variable under α β axle.
As the further improvement of such scheme, described phaselocked loop is reference synchronization coordinate system phaselocked loop.
The invention has the beneficial effects as follows: the island detection method based on idle-frequency positive feedback of the present invention does not have check frequency; Owing to there is not the artificial current disturbing introduced, also less on the impact of the quality of power supply, adopt when electrical network is normal, because the fluctuation of grid-connected point voltage frequency is very little, inverter only applies very little reactive current disturbance to grid-connected current, the power factor of combining inverter is not affected, also very little to grid-connected current harmonic influence; The present invention by the impact of load characteristic, can not detect the island state under high quality factor system.
Accompanying drawing explanation
Be further detailed below in conjunction with the drawings and specific embodiments:
Fig. 1 is the control system block diagram of the embodiment of the present invention;
Fig. 2 is the control flow chart of the embodiment of the present invention.
Embodiment
Below with reference to embodiment and accompanying drawing, design of the present invention and technique effect are clearly and completely described, to understand object of the present invention, characteristic sum effect fully.Obviously; described embodiment is a part of embodiment of the present invention, instead of whole embodiment, based on embodiments of the invention; other embodiments that those skilled in the art obtains under the prerequisite not paying creative work, all belong to the scope of protection of the invention.
With reference to Fig. 2, a kind of island detection method based on idle-frequency positive feedback, comprises the following steps:
Step 1, reads grid-connected point voltage ua, ub, uc in each sampling period;
Step 2, obtains frequency f by grid-connected point voltage through reference synchronization coordinate system phaselocked loop;
Step 3, judges whether grid-connected point voltage frequency f is greater than 50.2Hz, or is less than 47.2Hz, if so, then detect island state, shuts down, and disconnects the connection with electrical network; If not, then enter step 4;
Step 4, apply disturbance to grid-connected current, grid-connected point voltage frequency f is obtained Δ f through a second-order bandpass filter, bandpass filter can high frequency noise in filtering f and DC component, high frequency noise can affect the quality of power supply, and DC component can affect the set-point under stable state; Δ f is multiplied by a gain, the size of gain affects the speed of islanding detect speed, and gain is larger, and islanding detect speed is faster, but the stability that excessive gain meeting influential system runs under normal circumstances at line voltage; Value after Δ f is multiplied by gain obtains reactive current disturbance quantity Δ i by amplitude limit, reactive current disturbance quantity Δ i is added in reactive current given on.
Step 5, according to load idle-frequency characteristic:
, judge whether island state occurs.When electrical network disconnects, when the frequency that inverter detects increases, positive feedback effect can make the given increase of inverter q shaft current, can increase the reactive power that inverter exports like this.According to load in above formula idle-frequency characteristic, grid-connected point voltage frequency can increase idle to balance further.The frequency increased increases the reactive power of inverter further, and final frequency can exceed normal range of operation, and triggered frequency protection, island state is detected.Same positive feedback mechanism is had when frequency reduces.
With reference to Fig. 1, a kind of alone island detection system based on idle-frequency positive feedback, comprises combining inverter, load and electrical network, also comprises:
Electric current, voltage acquisition unit, be respectively used to the output three-phase current (i gathering combining inverter
a, i
b, i
c) and and site three-phase voltage (u
a, u
b, u
c);
Electric current, voltage abc-dq phase coordinates transducer, be respectively used to three-phase current, voltage (i
a, i
b, i
c), (u
a, u
b, u
c) convert rotatory current, voltage (i to
d, i
q), (u
dand u
q);
Reference synchronization coordinate system phase-locked loop pll, is connected with voltage abc-dq phase coordinates transducer, and for calculating phase-locked angle q and frequency f, wherein phase-locked angle qq is used for participating in the coordinate transform between electric current, voltage abc-dq phase coordinates transducer;
Bandpass filter, is connected with phase-locked loop pll, for calculating pass band width Δ f;
Gain module, amplifies for pass band width Δ f being multiplied by gain;
Limiter, is connected with gain module, for obtaining reactive current disturbance quantity Δ i by being multiplied by the Δ f value after gain through amplitude limit;
D axis scale integral controller, for by actual current d axle component i
dwith d shaft current specified rate i
d *error amount after comparing carries out integral transformation, obtains d axle controlled quentity controlled variable;
Q axis scale integral controller, for by actual current q axle component i
qwith q shaft current specified rate i
q *add the value of reactive current disturbance quantity Δ i compare after error amount carry out integral transformation, obtain q axle controlled quentity controlled variable;
Dq-α β coordinate converter, for converting the controlled quentity controlled variable under α β axle to by d axle, q axle controlled quentity controlled variable;
SVPWM modulator, for obtaining the break-make of each brachium pontis of PWM ripple control inverter by SVPWM modulation algorithm by the controlled quentity controlled variable under α β axle.
Embodiments of the present invention are not restricted to the described embodiments, as long as it reaches technique effect of the present invention with substantially identical means, all should belong to protection scope of the present invention.
Claims (5)
1., based on an island detection method for idle-frequency positive feedback, it is characterized in that comprising the following steps:
Step 1, reads grid-connected point voltage in each sampling period;
Step 2, obtains frequency f by grid-connected point voltage through phaselocked loop;
Step 3, judges whether grid-connected point voltage frequency f is greater than overfrequency or is less than underfrequency protection threshold value, if so, then detects island state, shuts down, and disconnects the connection with electrical network; If no, enter step 4;
Step 4, obtains pass band width Δ f by grid-connected point voltage frequency through bandpass filter, and pass band width Δ f is multiplied by proportional gain factor, and the value obtained obtains reactive current disturbance quantity Δ i by amplitude limit, reactive current disturbance quantity Δ i is added in reactive current given on;
Step 5, according to load idle-frequency characteristic:
，
During grid cut-off, the frequency that inverter detects increases, positive feedback effect can make the given increase of inverter q shaft current, the reactive power that inverter exports can be increased like this, thus frequency can increase further, the frequency of increase increases the reactive power of inverter further, and final frequency can exceed normal range of operation, coordinate passive island detection method, finally detect island state.
2. a kind of island detection method based on idle-frequency positive feedback according to claim 1, is characterized in that: the phaselocked loop in described step 2 is reference synchronization coordinate system phaselocked loop.
3. a kind of island detection method based on idle-frequency positive feedback according to claim 1, it is characterized in that: described over frequency protection threshold value is 50.2Hz, underfrequency protection threshold value is 47.2Hz.
4., based on an alone island detection system for idle-frequency positive feedback, comprise combining inverter, load and electrical network, characterized by further comprising:
Electric current, voltage acquisition unit, be respectively used to the output three-phase current (i gathering combining inverter
a, i
b, i
c) and and site three-phase voltage (u
a, u
b, u
c);
Electric current, voltage abc-dq phase coordinates transducer, be respectively used to three-phase current, voltage (i
a, i
b, i
c), (u
a, u
b, u
c) convert rotatory current, voltage (i to
d, i
q), (u
dand u
q);
Phase-locked loop pll, is connected with voltage abc-dq phase coordinates transducer, and for calculating phase-locked angle q and frequency f, wherein phase-locked angle qq is used for participating in the coordinate transform between electric current, voltage abc-dq phase coordinates transducer;
Bandpass filter, is connected with phase-locked loop pll, for calculating pass band width Δ f;
Gain module, amplifies for pass band width Δ f being multiplied by gain;
Limiter, is connected with gain module, for obtaining reactive current disturbance quantity Δ i by being multiplied by the Δ f value after gain through amplitude limit;
D axis scale integral controller, for by actual current d axle component i
dwith d shaft current specified rate i
d *error amount after comparing carries out integral transformation, obtains d axle controlled quentity controlled variable;
Q axis scale integral controller, for by actual current q axle component i
qwith q shaft current specified rate i
q *add the value of reactive current disturbance quantity Δ i compare after error amount carry out integral transformation, obtain q axle controlled quentity controlled variable;
Dq-α β coordinate converter, for converting the controlled quentity controlled variable under α β axle to by d axle, q axle controlled quentity controlled variable;
SVPWM modulator, for obtaining the break-make of each brachium pontis of PWM ripple control inverter by SVPWM modulation algorithm by the controlled quentity controlled variable under α β axle.
5. a kind of island detection method based on idle-frequency positive feedback according to claim 4, is characterized in that: described phaselocked loop is reference synchronization coordinate system phaselocked loop.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108344902A (en) * | 2017-10-24 | 2018-07-31 | 广东电网有限责任公司汕头供电局 | Dead electricity judgment method and device in face of the flexible DC power transmission device for transporting inspection personnel |
| CN110196398A (en) * | 2019-05-09 | 2019-09-03 | 合肥工业大学 | A kind of inverter anti-island effect detection method |
| CN110376483A (en) * | 2019-07-01 | 2019-10-25 | 浙江大学 | A kind of direct current island detection method based on specific frequency busbar voltage positive feedback |
| CN110824272A (en) * | 2019-10-24 | 2020-02-21 | 合肥为民电源有限公司 | Island detection method and island detection system |
| CN111257670A (en) * | 2020-01-16 | 2020-06-09 | 中南大学 | Method for determining island detection positive feedback gain range |
| CN111541271A (en) * | 2020-05-13 | 2020-08-14 | 广东电网有限责任公司韶关供电局 | Method and system for identifying island operation and grid-connected operation of small hydropower station |
| CN114696347A (en) * | 2022-05-31 | 2022-07-01 | 新风光电子科技股份有限公司 | Active island judgment system and method for energy storage system |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS603564A (en) * | 1983-06-20 | 1985-01-09 | Matsushita Electric Ind Co Ltd | Resonator characteristic measuring and selecting device |
| JPH06167551A (en) * | 1992-11-27 | 1994-06-14 | Honda Motor Co Ltd | Method and device for detecting remaiing charge in battery for electric vehicle |
| CN102437587A (en) * | 2011-09-23 | 2012-05-02 | 武汉新能源接入装备与技术研究院有限公司 | Island detection method of high-power photovoltaic grid-connected converter |
| CN103091578A (en) * | 2013-01-11 | 2013-05-08 | 天津理工大学 | Island detection method of photovoltaic grid-connected system |
| CN103645404A (en) * | 2013-12-16 | 2014-03-19 | 辽宁工业大学 | Micro-grid islanding detection method |
| CN103760434A (en) * | 2013-12-27 | 2014-04-30 | 浙江工业大学 | Self-adaption phase deviation island detection method based on fuzzy control |
| CN103954863A (en) * | 2014-04-28 | 2014-07-30 | 电子科技大学 | Three-phase grid-connected inverter anti-islanding detection method |
| CN104007349A (en) * | 2014-06-11 | 2014-08-27 | 江苏大学 | Fuzzy control island detection method based on wavelet transformation |
| CN104111406A (en) * | 2014-06-24 | 2014-10-22 | 许继电气股份有限公司 | Frequency feedback disturbance-based island detection method and apparatus |
| CN104316786A (en) * | 2014-10-10 | 2015-01-28 | 湖南大学 | Mixed isolated island detection method |
| CN104569696A (en) * | 2015-01-30 | 2015-04-29 | 闫朝阳 | Island detection method based on dq conversion and used for voltage per unit value positive feedback |
| CN104569685A (en) * | 2015-01-15 | 2015-04-29 | 华南理工大学 | Reactive phase angle error island detection method based on frequency positive feedback |
-
2015
- 2015-06-16 CN CN201510331374.6A patent/CN104950202A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS603564A (en) * | 1983-06-20 | 1985-01-09 | Matsushita Electric Ind Co Ltd | Resonator characteristic measuring and selecting device |
| JPH06167551A (en) * | 1992-11-27 | 1994-06-14 | Honda Motor Co Ltd | Method and device for detecting remaiing charge in battery for electric vehicle |
| CN102437587A (en) * | 2011-09-23 | 2012-05-02 | 武汉新能源接入装备与技术研究院有限公司 | Island detection method of high-power photovoltaic grid-connected converter |
| CN103091578A (en) * | 2013-01-11 | 2013-05-08 | 天津理工大学 | Island detection method of photovoltaic grid-connected system |
| CN103645404A (en) * | 2013-12-16 | 2014-03-19 | 辽宁工业大学 | Micro-grid islanding detection method |
| CN103760434A (en) * | 2013-12-27 | 2014-04-30 | 浙江工业大学 | Self-adaption phase deviation island detection method based on fuzzy control |
| CN103954863A (en) * | 2014-04-28 | 2014-07-30 | 电子科技大学 | Three-phase grid-connected inverter anti-islanding detection method |
| CN104007349A (en) * | 2014-06-11 | 2014-08-27 | 江苏大学 | Fuzzy control island detection method based on wavelet transformation |
| CN104111406A (en) * | 2014-06-24 | 2014-10-22 | 许继电气股份有限公司 | Frequency feedback disturbance-based island detection method and apparatus |
| CN104316786A (en) * | 2014-10-10 | 2015-01-28 | 湖南大学 | Mixed isolated island detection method |
| CN104569685A (en) * | 2015-01-15 | 2015-04-29 | 华南理工大学 | Reactive phase angle error island detection method based on frequency positive feedback |
| CN104569696A (en) * | 2015-01-30 | 2015-04-29 | 闫朝阳 | Island detection method based on dq conversion and used for voltage per unit value positive feedback |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108344902A (en) * | 2017-10-24 | 2018-07-31 | 广东电网有限责任公司汕头供电局 | Dead electricity judgment method and device in face of the flexible DC power transmission device for transporting inspection personnel |
| CN110196398A (en) * | 2019-05-09 | 2019-09-03 | 合肥工业大学 | A kind of inverter anti-island effect detection method |
| CN110376483A (en) * | 2019-07-01 | 2019-10-25 | 浙江大学 | A kind of direct current island detection method based on specific frequency busbar voltage positive feedback |
| CN110376483B (en) * | 2019-07-01 | 2020-06-16 | 浙江大学 | Direct current island detection method based on bus voltage positive feedback of specific frequency |
| CN110824272A (en) * | 2019-10-24 | 2020-02-21 | 合肥为民电源有限公司 | Island detection method and island detection system |
| CN110824272B (en) * | 2019-10-24 | 2021-07-09 | 合肥为民电源有限公司 | Island detection method and island detection system |
| CN111257670A (en) * | 2020-01-16 | 2020-06-09 | 中南大学 | Method for determining island detection positive feedback gain range |
| CN111257670B (en) * | 2020-01-16 | 2021-04-23 | 中南大学 | Method for determining island detection positive feedback gain range |
| CN111541271A (en) * | 2020-05-13 | 2020-08-14 | 广东电网有限责任公司韶关供电局 | Method and system for identifying island operation and grid-connected operation of small hydropower station |
| CN111541271B (en) * | 2020-05-13 | 2024-02-13 | 广东电网有限责任公司韶关供电局 | Identification method and system for island operation and grid-connected operation of small hydropower station |
| CN114696347A (en) * | 2022-05-31 | 2022-07-01 | 新风光电子科技股份有限公司 | Active island judgment system and method for energy storage system |
| CN114696347B (en) * | 2022-05-31 | 2022-08-26 | 新风光电子科技股份有限公司 | Active island judgment system and method for energy storage system |
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Application publication date: 20150930 |