Lightning protection of a smart grid sensor

• Application of the theory for lightning electromagnetic field computation on the protection of an electronic sensor used in power distribution lines.
• Use of a high-pass filter to protect the radio-frequency interface against the lightning surges coupled to the radio antenna.
• Use of a low-pass filter to protect the power-frequency voltage interface against the lightning surges coupled to the electric field antenna.
• Use of surge protective components to protect the power-frequency current interface against the lightning surges coupled to the magnetic field antenna.
• Assessment of the attenuation provided by the sensor chassis on the lightning magnetic field.

This paper presents the protection procedures implemented in a power line sensor in order to make it compatible with the electromagnetic environment, especially with the stresses imposed by lightning flashes. The paper includes the sensor description and simulation results of lightning surges coupled to the device through its external interfaces. It is shown that the protection of the radio-frequency circuitry requires the installation of a high-pass filter at the antenna port and that the protection of the voltage-measuring circuit can be accomplished by using a voltage divider combined with a low-pass filter. By its turn, the protection of the current-measuring circuit is achieved by the installation of surge protective components.