52 Part 12-5 of IEC 61400 specifies the procedures for assessing the significance of obstacles 53 and terrain variations on a proposed power performance measurement site and applies to the 54 performance testing of wind turbines of all types and sizes connected to the electrical power 55 network as described in other parts of the IEC 61400 series. The procedure applies to the 56 performance evaluation of specific wind turbines at specific locations.