... , especially in lighting waveform monitoring system, an observation system for overhead test line, maintenance data information system, power line protection system ... the double-layer design ranges from 90mm2 to 200mm2, suitable for rated voltages of 150kV, 250kV, 275kV, 380kV and 500kV ... three-layer design ranges from 200mm2 to 400mm2, suitable for rated voltages of 380kV, 420kV and 500kV in European ...