CN108918996A - Island detection method for distributed photovoltaic power generation system - Google Patents

Island detection method for distributed photovoltaic power generation system Download PDF

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Publication number
CN108918996A
CN108918996A CN201810629913.8A CN201810629913A CN108918996A CN 108918996 A CN108918996 A CN 108918996A CN 201810629913 A CN201810629913 A CN 201810629913A CN 108918996 A CN108918996 A CN 108918996A
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CN
China
Prior art keywords
inverter
carrier signal
frequency
grid
isolated island
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Pending
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CN201810629913.8A
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Chinese (zh)
Inventor
张颖
杨子龙
王波
王一波
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Institute of Electrical Engineering of CAS
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Institute of Electrical Engineering of CAS
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Priority to CN201810629913.8A priority Critical patent/CN108918996A/en
Publication of CN108918996A publication Critical patent/CN108918996A/en
Pending legal-status Critical Current

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38Arrangements for parallely feeding a single network by two or more generators, converters or transformers

Abstract

A kind of island detection method for distributed generation system is effectively combined the long-range detection method based on carrier communication with improved synovial membrane frequency drift method.When multicarrier receiver receives carrier signal, inverter receives low level signal, then isolated island does not occur, and inverter operates normally;When multicarrier receiver does not receive carrier signal, inverter receives high level signal, then isolated island may occur, and inverter starts improved synovial membrane frequency drift method, and the grid-connected dot frequency variation of real-time monitoring immediately.If grid-connected dot frequency exceeds 49.5-50.5Hz range, isolated island occurs, inverter is out of service;If within the scope of 49.5-50.5Hz isolated island does not occur for grid-connected dot frequency, if grid-connected dot frequency continues 2s within the scope of 49.5-50.5Hz, carrier communication breaks down, and inverter is out of service, alarm maintenance.

Description

Island detection method for distributed photovoltaic power generation system
Technical field
The present invention relates to a kind of island detection methods of distributed photovoltaic power generation system.
Background technique
With flourishing for distributed photovoltaic power generation, more and more distributed photovoltaic inverters are with high density multiple access The form of point is connected to the grid, and forms distributed photovoltaic inverter cluster.The validity of traditional island detection method is chosen by new War becomes the hot spot of current research suitable for the isolated island detection technique of distributed photovoltaic inverter group system.
Existing island detection method mainly includes that passive type detection method, active detection method and long-range detection method three are big Class, wherein passive type detection method and active detection algorithm are referred to as local isolated island detection method again.Passive type detection method is to utilize When using grid cut-off, the variation progress island effect detection of inverter output end frequency, voltage, phase or harmonic content, but It is that there are biggish check frequency (NDZ) for this method.Active detection method is the island detection method of current most study, Essence is that one small sample perturbations of addition in the output electric current of inverter mainly may be used according to the difference of disturbance quantity and disturbance result To be divided into frequency-shift type detection method, negative-sequence current disturbance, reactive disturbance etc..In the case where inverter cluster is grid-connected, using actively The phenomenon that formula detection method carries out isolated island detection, and there are the extensions of isolated island detection time even results in isolated island detection failure when serious, It is exactly so-called dilution effect.Long-range isolated island detection method refers to, and certain isolated island detection algorithm is added in distribution net side, general suitable The case where for more grid-connected inverters, wherein it is relatively conventional in a manner of power line carrier communication, but this method very great Cheng Depend on the reliability of carrier communication apparatus on degree, the unreliability of carrier communication isolated island can be detected cause malfunction can Energy.
Summary of the invention
In order to overcome the shortcomings of existing island detection method, the present invention proposes a kind of for distributed photovoltaic power generation system Island detection method.
The present invention is effectively combined the long-range detection method based on carrier communication with improved synovial membrane frequency drift method.This Invention receives the carrier signal that carrier signal generator is sent by the carrier signal receiver that inverter is nearby installed, and differentiation is No generation isolated island.When carrier signal receiver receives carrier signal, it is given to inverter and sends a low level signal, explanation does not have There is generation isolated island, inverter is normally incorporated into the power networks, and does not apply any disturbance;When carrier signal receiver does not receive carrier wave letter Number, it is given to inverter and sends a high level signal, then enter in doubtful isolated island set, isolated island may occur at this time, it is also possible to It is carrier communication loss of data, in this case, power quality is not the primary factor that system considers, inverter is using improvement Synovial membrane frequency drift method biggish disturbance is added, make every effort to quickly change electric network state, whether accurate judgement occurs isolated island.This hair It is bright to shorten isolated island detection time, it improves isolated island and detects reliability, reduce isolated island detection algorithm to the shadow of system power quality It rings.
The present invention adopts the following technical scheme that achieve the above object:
The carrier wave letter based on electric line carrier communication is installed in substation's secondary bus side of installation distributed generation system Number generator, every inverter nearby install carrier signal receiver.The sinusoidal signal of carrier signal generator selection 120kHz As carrier signal, peak value is about 6mV, is sent out at phase voltage zero crossing.The high frequency carrier of peak value 6mV is injected into 220V friendship In galvanic electricity pressure, the influence to power quality can be ignored.Three-phase voltage is high all in the high frequency carrier of zero crossing injection peak value 6mV Frequency carrier wave is in Coupling Between Phases, it is difficult to it eliminates, so carrier signal actually co-exists in three clusters in every half of voltage cycle, coupling High-frequency carrier signal amplitude very little out, carrier signal receiver compare threshold value by rationally setting, can only detect peak value The high frequency carrier of 6mV.When carrier signal receiver detects high-frequency carrier signal, to giving inverter to send a low level letter Number,;When carrier signal receiver does not detect high-frequency carrier signal, it is given to inverter and sends a high level signal.When inverse Become device and receive low level signal, illustrates that power grid is normal, isolated island does not occur, inverter continues to be incorporated into the power networks;Inverter once connects Receive high level signal, explanation may have occurred and that isolated island, into doubtful isolated island Set Status, inverter by actively apply compared with Big phase angle disturbance, judges whether isolated island really occur as early as possible, and power quality is not to consider emphasis at this time.
Enter doubtful isolated island Set Status after, inverter and it is non-immediate stopping be incorporated into the power networks, but immediately starting improve Synovial membrane frequency drift method.Improved synovial membrane frequency drift method is disturbed relative to common synovial membrane frequency drift method, increased phase angle Momentum θdisIt is bigger, be:
Wherein, θdisFor phase angle disturbance quantity, f is the grid-connected dot frequency measured, f0For rated frequency 50Hz, θMAXFor maximum phase Angle disturbance quantity, generally takes 5 ° to 15 °, takes 20 ° herein, fMAXFor maximum system frequencies, 51 to 53Hz are generally taken, takes 51Hz herein, Actively to realize biggish phase angle disturbance.
After inverter uses improved synovial membrane frequency drift method, the grid-connected dot frequency variation of real-time monitoring, if grid entry point frequency Rate exceeds 49.5-50.5Hz range, then isolated island has occurred, inverter is out of service;If grid-connected dot frequency is in 49.5-50.5Hz In range, then isolated island does not occur, if grid-connected dot frequency continues 2s within the scope of 49.5-50.5Hz, carrier communication occurs Failure, inverter is out of service, alarm maintenance.
For the present invention only when carrier signal receiver does not receive carrier signal, inverter just actively applies phase angle disturbance Amount, avoids active detecting method long lasting effect caused by power quality, while avoiding the long-range inspection based on power line carrier Survey method is unreliable to cause isolated island protection misoperation.Present invention reduces isolated island detection times, improve reliability of islanding detection, Reduce influence of the island detection method to power quality.The invention is particularly suited to distributed photovoltaic inverter cluster is grid-connected Situation.
Detailed description of the invention
Fig. 1 island detection method implements topological diagram;
Fig. 2 island detection method control logic figure.
Specific embodiment
The present invention is further illustrated below in conjunction with the drawings and the specific embodiments.
Island detection method implementation topological diagram of the present invention for distributed generation system is as shown in Figure 1.In substation Secondary bus surveys installation carrier signal generator, and carrier signal receiver is installed near every inverter.Carrier signal occurs The carrier signal that device is selected is the sinusoidal signal that 120kHz, peak value are about 6mV, whenever phase voltage zero crossing on power circuit The carrier signal that peak value is about 6mV is sent, is injected into 220V ac phase voltage, influence of this carrier signal to power quality can To ignore.There are the carrier signal that cluster amplitude is about 6mV in every half of cycle of phase voltage, i.e. carrier signal occurs The carrier signal that device is sent, there is also the two smaller carrier signals of cluster amplitude in addition to this, this two clusters carrier signal is due to three Phase voltage is all in zero crossing injected carrier signal, and carrier signal is obtained from Coupling Between Phases.The load being mounted near inverter Wave signal receiver can only detect the carrier signal of peak value about 6mV by the voltage detection threshold of reasonable set, and ignore Couple the obtained smaller two clusters signal of amplitude.
Inverter is connect with carrier signal receiver by a signal line.When carrier signal receiver detects that carrier wave is believed Number, the low level signal just sent to inverter;Carrier signal receiver does not detect carrier signal, just to inverter Send a high level signal.Fig. 2 is control logic figure of the present invention for the island detection method of distributed generation system.When When inverter receives low level signal, isolated island does not occur for distributed generation system, and inverter is normally incorporated into the power networks;When inverter is received When to high level signal, isolated island may occur for distributed generation system, and into doubtful isolated island set, inverter is actively implemented at this time Compared with large disturbances, to determine whether that isolated island occurs as early as possible.Inverter uses improved synovial membrane frequency drift method, and the phase angle of application is disturbed Momentum θdisFor:
Wherein, f is the grid-connected dot frequency measured, f0For rated frequency 50Hz, θMAXFor maximum phase angle disturbance quantity, 20 ° are taken, fMAXFor maximum system frequency, 51Hz is taken, then practical phase angle disturbance quantity θdisFor:
While inverter implements the disturbance of larger phase angle, the grid-connected dot frequency of real-time monitoring, if grid-connected dot frequency exceeds Isolated island has then occurred for 49.5-50.5Hz range, and inverter is out of service, if grid-connected dot frequency is in 49.5-50.5Hz range It is interior, then isolated island does not occur, if grid-connected dot frequency continues 2s within the scope of 49.5-50.5Hz, carrier communication breaks down, Inverter alarm is simultaneously out of service.

Claims (3)

1. a kind of island detection method for distributed generation system, it is characterised in that:The detection method passes through inversion The carrier signal receiver that device is nearby installed receives the carrier signal that carrier signal generator is sent, and discriminates whether that isolated island occurs; When carrier signal receiver receives carrier signal, just to giving inverter to send a low level signal, illustrate that there is no orphans Island, inverter are normally incorporated into the power networks;When carrier signal receiver does not receive carrier signal, it is electric just to send a height to inverter Ordinary mail number;Then enter in doubtful isolated island set, isolated island may occur at this time, it is also possible to carrier communication loss of data, this In the case of, inverter uses improved synovial membrane frequency drift method, applies biggish phase angle disturbance;Inverter real-time monitoring grid entry point Isolated island has occurred for frequency, inverter is out of service if grid-connected dot frequency exceeds 49.5-50.5Hz range;If grid entry point Within the scope of 49.5-50.5Hz isolated island does not occur for frequency then, if grid-connected dot frequency continues 2s in 49.5-50.5Hz range It is interior, then illustrate that carrier communication breaks down, inverter is out of service, issues fault alarm and is overhauled.
2. the island detection method according to claim 1 for distributed generation system, it is characterised in that:Applied Phase angle disturbance quantity θdisFor:
Wherein, f is the grid-connected dot frequency measured, f0For rated frequency 50Hz, θMAXFor the disturbance of maximum phase angle, 20 ° are taken, fMAXFor most Big system frequency, takes 51Hz,
Then actual phase angle disturbance quantity is:
3. the island detection method according to claim 1 for distributed generation system, it is characterised in that:The load Wave generator is mounted on substation's secondary bus side of distributed generation system, and every inverter nearby installs carrier signal Receiver, inverter are connect with carrier signal receiver by a signal line.
CN201810629913.8A 2018-06-19 2018-06-19 Island detection method for distributed photovoltaic power generation system Pending CN108918996A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110289637A (en) * 2019-07-16 2019-09-27 中腾微网(北京)科技有限公司 A kind of joint island detection method that region multi-inverter is grid-connected

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102005742A (en) * 2010-11-17 2011-04-06 中国电力科学研究院 Distributed power generation island detection system and method based on power frequency carrier wave
CN103124068A (en) * 2013-01-31 2013-05-29 中国电力科学研究院 Anti-islanding protection system for distributed grid-connected system and protection method of anti-islanding protection system
CN103941118A (en) * 2014-03-26 2014-07-23 中国科学院电工研究所 Island detecting method for photovoltaic power generation grid-connected inverter trunking system
CN105914776A (en) * 2016-04-13 2016-08-31 上海交通大学 Quick intelligent anti-island system and quick intelligent anti-island method with power grid fault self-recovering capability
CN106019010A (en) * 2016-05-23 2016-10-12 南昌大学 Mixed island detection method based on combination of slide mode frequency shift method and passive method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102005742A (en) * 2010-11-17 2011-04-06 中国电力科学研究院 Distributed power generation island detection system and method based on power frequency carrier wave
CN103124068A (en) * 2013-01-31 2013-05-29 中国电力科学研究院 Anti-islanding protection system for distributed grid-connected system and protection method of anti-islanding protection system
CN103941118A (en) * 2014-03-26 2014-07-23 中国科学院电工研究所 Island detecting method for photovoltaic power generation grid-connected inverter trunking system
CN105914776A (en) * 2016-04-13 2016-08-31 上海交通大学 Quick intelligent anti-island system and quick intelligent anti-island method with power grid fault self-recovering capability
CN106019010A (en) * 2016-05-23 2016-10-12 南昌大学 Mixed island detection method based on combination of slide mode frequency shift method and passive method

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
孙振奥等: "适用于分布式多逆变器系统的混合孤岛检测法", 《中国电机工程学报》 *
雷鸣宇等: "适用于并网逆变器集群系统孤岛检测的改进滑模频率漂移法", 《电网技术》 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110289637A (en) * 2019-07-16 2019-09-27 中腾微网(北京)科技有限公司 A kind of joint island detection method that region multi-inverter is grid-connected

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Application publication date: 20181130