• HVAC, HVDC and industrial grounding systems in multilayered soils and transferred potentials to buried structures such as pipelines.
• Effects of cathodic protection installations on other metallic structures.

Since today's higher system voltages and fault current levels require substantial and expensive grounding installations, SES's computer tools help customers increase their design efficiency while significantly reducing their expenditures.

For example, in 1986, Alberta Power Limited wanted to increase the capacity of one of its substations which was surrounded by buried pipelines. Concerned that a ground fault at the station or on the transmission line could damage the pipelines, the pipeline company refused to approve the expansion unless expensive mitigation matting was deployed around many pipeline sections.

Fortunately, SES demonstrated to the satisfaction of both parties that the projected expansion would actually result in a slight decrease in interference levels, thus eliminating the need for the proposed mitigation.

• Low frequency electromagnetic interference effects caused by power system transmission lines on pipelines, railways, telecommunication lines and similar long conductors, during steady state and fault conditions.
• Low frequency conductive interference effects caused by power system grounds on non-energized metallic structures.

With the current trend towards minimizing the amount of land available to private and public utilities, installations such as powerlines, pipelines, railway tracks, communication lines and similar services are being forced to share relatively narrow tracts of land, thus increasing the need for mitigation systems.

Responding to this need, SES has developed a design which combines the functions of grounding, gradient control, and cathodic protection into a single mitigation system. SES's design is a safer and more economical alternative to the "cancellation wire" technique which transfers high pipeline potentials to the opposite side of the right-of-way, where hazardous potentials are least expected. Finally, SES has made important contributions to the concept of evaluating interference levels with respect to local earth rather than remote earth. This has resulted in a more precise reference point and greatly reduced mitigation requirements.

SES's software can accurately compute the electric and magnetic fields caused by currents flowing in overhead and buried conductors, including house wiring and water pipes. This software can analyze:

• Electric and magnetic fields generated by arbitrarily oriented current-carrying conductors located above ground and partially or totally buried in soil. Computations are carried out accurately at frequencies ranging from a few hertz to hundreds of megahertz.
• Effects of lightning strikes or high current transient surges on power system networks, pipelines and similar non-energized installations.

Lightning and high current transient surges can cause significant equipment damage and induce lethal stress voltages. Recently SES helped Florida Power & Light successfully solve a capacitor transient discharge problem and assisted South Carolina Electric & Gas in solving a distribution line lightning problem.

New soil resistivity measurement procedures developed by SES make it possible to obtain accurate data and achieve significant cost savings by diminishing the need to overdesign grounding and mitigation systems. These procedures provide:

• Effective soil resistivity measurements at sites with high level of power system interference and stray voltages. Multilayer soil interpretation for horizontally and vertically layered soil structures.