Verification and Analysis of Lumped-circuit Approximate Models of Multiconductor Transmission Lines Excited by Fast Rising Pulse

To investigate the coupling mechanism between fast rising pulses and transmission lines, we established lumped-circuit models of both lossless and lossy transmission lines, and verified them with other simulation methods and experiments. Taking lossless three-conductor transmission line with frequency-dependent loads as the representative, we built a lumped-circuit model of lossless line and verified it using the state variable technique. Simulation results indicate that the shorter the segment of transmission line is, the more consistent with actual value the simulation results will be, and the longer time the simulation will take. For a fixed segment length, simulation time increases with the length of transmission line in a linear manner. Meanwhile, taking a four-core cable with resistance loads,capacitance, and transient voltage suppressor as the representative, we established a lumped-circuit model of lossy line, and verified its simulation results by experiments. It is found that the response of loads is highly dependent on the configuration of core cables and the types of applied loads. It is concluded that lumped-circuit approximate models can be employed to solve the cross-talk problems for transmission lines with frequency-dependent loads and/or nonlinear loads, and they are useful for protection design against electromagnetic pulses for multi-core interconnect systems.