Lightning protection system for a wind turbine blade

A rotor blade of a wind turbine, comprising:

• a leading-edge section with a leading edge and a trailing edge section with a trailing edge;
• a root section with a root and a tip section with a tip;
• a shell with a suction side shell section and a pressure side shell section, wherein an outer surface of the shell defines an outer shape of the rotor blade and an inner surface of the shell defines a cavity of the rotor blade;
• a lightning protection system with an internal down conductor extending from the root section of the rotor blade to the tip section of the rotor blade, wherein the internal down conductor is connectable at the root section to a grounding system of a remainder of the wind turbine and at the tip section to an at least one tip lightning receptor which is positioned at the outer surface of the rotor blade;
• and
• an electrically insulating tip unit, wherein the electrically insulating tip unit is arranged in the tip section of the rotor blade in a cavity of the rotor blade and wherein the electrically insulating tip unit encapsulates at least a part of the internal down conductor in the tip section of the rotor blade, wherein:
• at least a part of the electrically insulating tip unit covers an entire area between a part of the suction side shell portion and a part of the pressure side shell portion, and
• a connection between the electrically insulating tip unit and the suction side shell portion as well as a connection between the electrically insulating tip unit and the pressure side shell portion is a cast interface, respectively;
• the electrically insulating tip unit comprises a tip part which covers the entire area between the leading edge and the trailing edge of the rotor blade.