Low Frequency Approximation

The LOW FREQUENCY APPROXIMATION keyword is applicable only when MHARNESS® is called from the software program EMA3D. When MHARNESS is used as a standalone program, this keyword is ignored. The LOW FREQUENCY APPROXIMATION is particularly applicable when modeling MHARNESS cables within a three-dimensional geometry that is being subjected to low frequency excitation, such as lightning.

When implementing the LOW FREQUENCY APPROXIMATION some keywords, if present within the MHARNESS input file are ignored. These keywords are listed below.

SHIELD GLOBAL TRANSFER DIRECTION

SHIELD TRANSFER DIRECTION

In addition, all shield transfer inductance values are set to zero and only resistive circuit terminations can be specified. This is acceptable in a low frequency limit.

The required input file text line format is:

!LOW FREQUENCY APPROXIMATION