A Communication Based Islanding Detection Method for Photovoltaic Distributed Generation Systems

Table 2

A comparison of current islanding detection methods.

Features	Local methods			Remote methods (communication based methods)
	Passive	Active	Hybrid	PLL	SCADA
Operation principle	Measuring the PCC parameters	Adding a disturbance signal to the grid	A combination of active and passive methods	Grid impedance change in PCC	Using receiver and transmitter sensors between DG and grid
NDZ	Large	Small	Small	No	No
Response time	Short	Shorter than passive methods	Longer than active methods	Fast	Faster
Detection failure	Yes, when matching powers of inverter, load, and grid	Yes, only in high quality factor	Smaller than active and passive methods	No, except a few specific conditions	No, except a few specific conditions
Effect on dist. grid	No	Yes	Yes, but smaller than active methods	No	No
System cost	Minimum cost	Average cost	High cost	Very high cost	Extremely high cost
Multiple inverter connection	No	Yes	Yes	No	No
Effect on power quality	No	Decreases the power quality of the system	Decreases the power quality of the system, but with smaller effect compared to active methods	No	No