The islanding phenomena of PV inverter are obviously influenced by the regenerative loads such as motor load and resonance circuit. In Japanese situation, the motor loads of 1 KW or less are used in the certification test and evaluated in order to test the islanding detection device in a severer case from the viewpoint of safety. However, the motor load is not very clear in the specification of a standard motor to use for the examination so that there are diverse and unspecified kinds. Accordingly, it is certainly not easy to standardize the motor load for certification test around the world. On the other hand, in IEEE929-2000 and IEC62109CD2 standard, resonance circuit is used instead of motor load for the examination with consideration of regenerative load characteristic. Therefore, it is necessary to confirm whether the resonance circuit can simulate the motor load properly under the islanding condition