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This software package is a transmission and distribution line analyzer for rapid line parameter computations, steady-state and fault-induced electromagnetic interference studies (whether inductive or conductive) as well as an electric and magnetic field calculator.

Technical Description

The SESTLC Pro software package is a transmission and distribution line analyzer for rapid line parameter (constants), EMF and steady-state or fault-induced electromagnetic interference estimates (whether inductive and conductive). It can be used to quickly estimate line parameters, electric fields, and magnetic fields associated with arbitrary configurations of transmission and distribution lines. It also estimates voltages and currents generated by electromagnetic interference on other neighboring metallic utilities, such as pipelines, railways and communications lines. The software has been designed with simplicity in mind, providing an abundance of useful information with minimal data entry, when applied to simple system configurations. This can be very helpful for preliminary analyses of more complex systems. A simplified data entry mode is available for cases where the exposed line is always parallel to the transmission line, however an exposed line does not have to be parallel to the transmission line in a SESTLC Pro model. Moreover, the path followed by the transmission line is no longer limited to a straight line. This new enhancement also eliminates the limitations of uniform span lengths and tower impedances that existed in previous versions of the program, where the transmission line could only follow a straight path.

Keep in mind that for more complex systems or more detailed studies, the Right-of-Way or MultiFields software packages are recommended.

A summary of the estimations that can be made with SESTLC Pro:

  1. Line parameters of overhead transmission lines
  2. Electric & magnetic fields at given observation profiles
  3. Normal load (steady-state) condition inductive interference from a straight or jagged transmission line on a parallel or jagged exposed line
  4. Fault condition inductive and conductive interference from a straight or jagged transmission line on a parallel or jagged exposed line
  5. Inductive and conductive interference calculations between arbitrarily oriented and jagged transmission lines as well as buried jagged exposed lines in a homogenous earth.

User Interface

SESTLC Pro computes the line parameters of the transmission lines, the electric and magnetic field at selected observation points, the induced stress voltages and longitudinal currents on the exposed line during steady state conditions and fault conditions on the transmission lines.

The transmission line and exposed circuit can be described as either a simple “parallel” line or as a “jagged” path that can follow an arbitrary 3D linear path.

In parallel line mode, the exposed circuit includes a central portion running parallel to the transmission line, continuation portions running perpendicular to the transmission line on both sides of the central portion and termination shunt impedances at both ends. Note that with this setup the continuation portions are not subject to EMF from the transmission line. The longitudinal direction of the transmission line is along the X axis. The coordinates of the exposed line are defined with respect to this coordinate system.

In jagged exposed line mode, the path followed by the exposed conductors consists of any number of sections. Each section can have its own geometrical and electrical characteristics. The configuration is determined by the coordinates of the path.

In jagged transmission line mode, transmission lines can follow arbitrary 3D paths, greatly expanding the range of applicability of the program, and without substantially increasing the time required to perform the computations. This was achieved due to the implementation of highly optimized algorithms that were developed for the calculation of the electromagnetic fields due to point sources and linear conductors. With this new option, transmission line spans can be of different lengths and tower impedances can differ for different sections of the line. With this enhancement, SESTLC can provide quick and reliable estimates of ac interference levels on pipelines (or other affected conductors) exposed to a jagged transmission line, under both steady-state and fault conditions.