The wind farm is among the first in the world to use a conical joint at the top of its monopiles to prevent transition pieces from slipping.
The design was taken forward by the London Array in parallel with a separate industry research project established to overcome problems that have been reported on some monopile foundations.
"The construction and design of what will be the world's largest wind farm is a major technical and engineering challenge, and we have paid close attention ...
to ensure that we got the design absolutely right," said London Array project manager Soren Thorbjorn Larsen. In addition to slippage, water depths and the mobility of the seabed across the site were also important.
The new foundation features a gently sloping cone at the top of the monopile that sits inside an inverted cone at the bottom of the transition piece. A layer of grout lies between the two surfaces.
Phase one of London Array is due for completion by the end of this year. The DNV certification covers the wind farm's 175 turbines, with a combined capacity of 630MW, and two offshore substations.
London Array is being developed by a consortium comprising Dong Energy (50%), E.on (30%) and Masdar (20%).