Apparatus, method and system for detecting an islanding state of a power generation device

A method comprising:

• acquiring a current amount at a substation;
• acquiring a voltage phasor at a power generation device;
• determining an interconnection impedance between the power generation device and the substation according to a ratio of a variation of the voltage phasor and a variation of the current amount within a same time period;
• and
• determining that the power generation device is in an islanding state under the condition that the interconnection impedance meets a predetermined condition.

An apparatus comprising:

• a first acquisition unit for acquiring a first voltage phasor and a first current phasor at a substation;
• a second acquisition unit for acquiring a second voltage phasor at a power generation device;
• and
• a processing unit connected with the first acquisition unit and the second acquisition unit, for determining an interconnection impedance between the power generation device and the substation within a predetermined time period, and determining that the power generation device is in an islanding state under a condition that the interconnection impedance is greater than a predetermined interconnection threshold, wherein
• the interconnection impedance is determined based on a ratio corresponding to a voltage drop caused by a current flowing through an equivalent impedance between the substation and the power generation device.