Page 72 - Alternative Energy Systems in Building Design
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48 SOLAR POWER SYSTEM PHYSICS AND TECHNOLOGIES
Islanding is a condition that occurs when the inverter continues to produce power
during a utility outage. Under such conditions, the power produced by a PV system
becomes a safety hazard to utility workers, who could be exposed inadvertently to haz-
ardous electric currents. Because of this, inverters are required to include anti-
islanding control circuitry to cut the power to the inverter and disconnect it from the
grid network.
Anti-islanding also prevents the inverter output power from getting out of phase with
the grid when the automatic safety interrupter reconnects the inverter to the grid (which
could result in high-voltage spikes that can cause damage to conversion and utility
equipment). Figures 3.13 and 3.14 show the electronics of a Solectria Renewables
inverter and a typical installation.
Figure 3.13 Internal view of inverter electronics. Photo
courtesy of Solectria Renewables.
