[RE-wrenches] anti islanding?

[Bill Brooks]

August,

Probably the best simple explanation is in "Connecting to the Grid",
published by the Interstate Renewable Energy Council and the North Carolina
Solar Center. It is in its 6th edition. I wrote the original version of the
document over 15 years ago.

Bill.

Quote from Document:

"Grid-tied inverters monitor the utility line voltage and frequency
continuously. When abnormal voltage or frequency conditions occur on the
utility system, they shut themselves off quickly (or "cease to energize,"
the phrase that appears in technical interconnection standards).
Unintentional islands with inverters are very difficult to sustain because
the inverter is not designed to regulate output voltage. Instead, these
inverters produce current proportional to the available power from the prime
power source. An Islanding condition would require the source power to match
real and reactive load conditions thus sustain an unintentional island. With
dynamic loads and fixed power source the natural tendency of the island to
shift outside the allowable voltage and frequency limits that would
otherwise cause the inverter to trip. Extensive testing of inverters at
Sandia National Laboratories, under a variety of laboratory-controlled
worst-case conditions, led to the development of specific
islanding-detection (or anti-islanding) techniques and a generalized test
procedure for evaluating the efficacy of any anti-islanding device. These
and other anti-islanding techniques reduce the already low probability of
inverter islanding such that devices that pass this test, which is detailed
in IEEE 1547.1-2005, are considered non-islanding. Informative discussions
of islanding and anti-islanding inverters are included in the annexes to
IEEE 929-2000  and in a study titled Results of Sandia National Laboratories
Grid-Tied Inverter Testing,   published in 1998 by Sandia National
Laboratories."
******

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of August Goers
Sent: Saturday, February 13, 2010 8:29 AM
To: RE-wrenches
Subject: [RE-wrenches] anti islanding?

Hi Wrenches,

Does anyone know where I can go to read about general information on how
grid tied inver anti islanding works? I'd like to be able to describe this
in better detail to our tech-savvy clients. 

Thanks,

August


August Goers

Luminalt Energy Corporation
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