A wind turbine blade, comprising: a proximal end, where the blade is attached to a rotor hub at a blade root, and a distal end, where the blade tapers to form a blade tip, a lightning protection system, comprising: at least one lightning receptor (148, 154) exposed on a surface of the blade for receiving a lightning strike, and a lightning down conductor coupled to the lightning receptor (148, 154) for relaying lightning current from a lightning strike, the down conductor running internally within the blade and coupled to an electrical ground, and a lightning current measurement system, for deriving parameters of a lightning strike, comprising: a lightning current sensor (170, 172) comprising a coil of metal substantially circumscribing the down conductor, the coil in proximity with the down conductor so as to detect magnetic field fluctuations, wherein the lightning current sensor is provided with a sensor protection system for preventing dielectric breakdown, the sensor protection system comprising insulation about the coil of metal, the insulation having a dielectric breakdown voltage of at least 20kV, a lightning analytical system, for receiving an output reading from the lightning current sensor (170, 172) and to provide lightning current parameters, and a signal conversion unit coupled between the lighting current sensor (170, 172) and the lightning analytical system; wherein the signal conversion unit is physically located in the blade and is separated from the blade root by a spacing distance so as to reduce the occurrence of a flashover. a proximal end, where the blade is attached to a rotor hub at a blade root, and a distal end, where the blade tapers to form a blade tip, a lightning protection system, comprising: at least one lightning receptor (148, 154) exposed on a surface of the blade for receiving a lightning strike, and a lightning down conductor coupled to the lightning receptor (148, 154) for relaying lightning current from a lightning strike, the down conductor running internally within the blade and coupled to an electrical ground, and at least one lightning receptor (148, 154) exposed on a surface of the blade for receiving a lightning strike, and a lightning down conductor coupled to the lightning receptor (148, 154) for relaying lightning current from a lightning strike, the down conductor running internally within the blade and coupled to an electrical ground, and a lightning current measurement system, for deriving parameters of a lightning strike, comprising: a lightning current sensor (170, 172) comprising a coil of metal substantially circumscribing the down conductor, the coil in proximity with the down conductor so as to detect magnetic field fluctuations, wherein the lightning current sensor is provided with a sensor protection system for preventing dielectric breakdown, the sensor protection system comprising insulation about the coil of metal, the insulation having a dielectric breakdown voltage of at least 20kV, a lightning analytical system, for receiving an output reading from the lightning current sensor (170, 172) and to provide lightning current parameters, and a signal conversion unit coupled between the lighting current sensor (170, 172) and the lightning analytical system; a lightning current sensor (170, 172) comprising a coil of metal substantially circumscribing the down conductor, the coil in proximity with the down conductor so as to detect magnetic field fluctuations, wherein the lightning current sensor is provided with a sensor protection system for preventing dielectric breakdown, the sensor protection system comprising insulation about the coil of metal, the insulation having a dielectric breakdown voltage of at least 20kV, a lightning analytical system, for receiving an output reading from the lightning current sensor (170, 172) and to provide lightning current parameters, and a signal conversion unit coupled between the lighting current sensor (170, 172) and the lightning analytical system; wherein the signal conversion unit is physically located in the blade and is separated from the blade root by a spacing distance so as to reduce the occurrence of a flashover.