Smart grid is the latest development trends of the power systems in the world. With a large number of intelligent substation pilot projects put into construction, the need for intelligent electronic devices (IEDs) is increasing quickly. There is great concern on the electromagnetic compatibility problem of IEDs in a gas insulated substation. IEDs may be confronted with severe transient electromagnetic disturbance due to proximity with the primary disturbance sources like the switching operation of a disconn...