6IEC60840, Power cable with extruded insulation and their accessories for rated voltages above 30 kV (Um=36 kV) up to 150 kV(Um=170 kV)-Test methods and requirements[S], 2004.
7IEC62067, Power cable with extruded insulation and their accessories for rated voltages above 150 kV(Um = 170 kV) up to 500 kV(Um = 550kV)-Test methods and requirements[S], 2001.