Time-domain Behavioral Modeling and Protection Effect Simulation of Lightning Protection Device for Short-wave Transmission System

In this paper the time-domain behavioral modeling method and simulation results of lightning protection device for short-wave transmitting system were introduced. The lighting protection device consisted of two stage modules. The first stage module featured self-breakdown discharge switch, whose current capability was larger than 200 kA, and response time less than 50 ns. The second stage module was composed of a π-structured decoupling network and micro GDT (gas discharge tube), whose current capability was larger than 10kA, and response time less than 10 ns. For the purpose of analyzing the time-domain response characteristics of the protection device under the circumstances of high voltage and large current of lightning, behavioral model describing the process of field emission and gas discharge was established with SPICE based language. The simulation results showed that the action delay of the protection modules decreased as the rising rate of the lightning impulse voltage increased. In the case of the voltage rising rate being larger than 10 kV/ns, the action delay of the first stage module was less than 10 ns and the second stage less than 2 ns. The π-structured decoupling network, consisting of two high voltage capacitors and one shunt inductor, played the role of isolation between the two protection stages to prevent the GDT in the first stage from acting faster than the large current switch in the first stage.