The study and development of anti-islanding controls are very important in wind and solar applications.
In general, there are three islanding detection methods, communication-based method, passive resident method and active resident method.
Communication-based method is limited by the communication speed. The other two are implemented in the grid-connected converter. On one side, passive resident method is based on grid voltage detection and frequency detection directly. There is no harmonic generated with these methods. But the non-detection zone is big. On the other side, active resident method is to change the current injected into the grid and check the corresponding response of grid voltage. It includes slide-mode frequency shift, active frequency drift, Sandia frequency shift or grid impedance detection. Its non-detection zone is small, but it would worse the power quality. Sometimes the passive method and active method would be used together.
In general, there are three islanding detection methods, communication-based method, passive resident method and active resident method.
Communication-based method is limited by the communication speed. The other two are implemented in the grid-connected converter. On one side, passive resident method is based on grid voltage detection and frequency detection directly. There is no harmonic generated with these methods. But the non-detection zone is big. On the other side, active resident method is to change the current injected into the grid and check the corresponding response of grid voltage. It includes slide-mode frequency shift, active frequency drift, Sandia frequency shift or grid impedance detection. Its non-detection zone is small, but it would worse the power quality. Sometimes the passive method and active method would be used together.
I looked a 1541 and it seems the wrong standard number, it seems the number 1547a.
http://grouper.ieee.org/groups/scc21/1547a/email/msg00155.html
But these rules result from big power plant exploitation.
In low voltage grids at lower power, islanding can be detected if the single phase voltages are not in the range: If the PV (or wind) power is bigger than the load, the voltage will be too high, if the PV power is lower than the load, one gets an undervoltage. It is indeed important to protect other users from large voltage deviations. Abnormal voltages might also result from a loss of neutral connection, as renewbles not always meke a neutral. So, disconnecting on voltage limits would be sufficient for small installations, but grid owners like to make it difficult, which is normal for high power, but not for small installations.
You can also look at IEC standard, this standard has some roles about low voltage
Mr. Gharavi, your answer could be much more valuable if at least refer to which IEC is relevant acording to you, as there are many.
Do you mean: IEC 62116:2014 ?
"Standards are the best kept secrets"
They are too expensive for normal users, the most expensive paper, apart from money itself...
Thanks for your email. The reason why I did not mention the number of standard was because I did not remember the number exactly. I remember it was mostly about photovoltaic system is-landing mode. Let me have a search on Internet and then I will tell you exactly which IEC standard was about the mentioned problem.
Comparison of rate of change of frequency protection. The local rate of change of frequency protection is compared with that of the grid as a whole and if there is a difference, the generator protection operates. More simply, if the grid as a whole suffers a frequency transient, it transmits a blocking signal to block the operation of generator rate of change of frequency (ROCOF) protection. Please google COROCOF for futher details.
In Germany there was a big problem that renewables were thrown of the grid at a big grid transient (Saling ship with open high voltage line at the Elbe). Those reguations should be abandonned as they have their origin in alternators. If you disconnect an alternator at light local load, the frequency rises and the voltage may rise also. But why should a frequency from a converter rise? So, this principle is not valid for converters. In converters, one will mainly see it in voltage not in frequency.
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