Anti island protection: Series inverter VS Centralized inverter

The island effect: refers to the power outages due to failure or maintenance of the part of the grid, power lines power supplied by grid connected power generation device, and constitute a self powered islanding phenomenon with the surrounding load. GB/T19964-2012 standard require power station with anti islanding protection equipment, usually the inverter adopts active + passive double anti islanding protection, to protect the inverter in any case can be reliably disconnected from the grid connection. Active protection is usually used to inject small interfering signal to the power grid, by detecting the feedback signal to determine whether the loss of electricity, while the passive protection usually uses the detection output voltage, frequency and phase to determine the occurrence state of the island.
Series inverter: the AC side is directly connected in parallel, and the active protection can not be applied in the multi machine parallel system because of the active protection, unable to perform active protection in isolated island protection.
Application risks: the resonant island will cause a security threat to the line maintenance personnel, and damage the electrical equipment, seriously affect the safety of the operation of the power station, etc..
Centralized inverter: AC output without concentration, direct access to the dual split winding transformer, while the implementation of active and passive island protection.

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