Electrical Utility System Studies

TriAxis performs electrical distribution system studies such as Long Range Plans and Short Range Construction Work Plans. TriAxis uses Aspen Distriview software to build system circuit models and perform circuit analysis. TriAxis utility system planning involves estimating load growth and construction cost, and merges the resulting system technical requirements with optimized improvement recommendations and the utilities operation and maintenance goals.

TriAxis provides the following types of studies for our utility clients:

Load Flow & Voltage Drop A Load Flow & Voltage Drop study is necessary to compare actual line loads with rated capacities, and to determine if service voltage levels are within the required limits. Using ASPEN Distriview and other software tools, TriAxis provides radial and network electrical system analysis. We can quickly build a new electrical model from system circuit maps using standard system network parameters, or we can use a client’s existing system model database and software. Using load data, we can then examine the normal and contingency voltage drops in an electric system.

Fault Current Studies are needed to:

  1. Compare equipment fault current ratings with the actual fault current available under different types and locations of system faults, and
  2. Coordinate the operation of circuit breakers, reclosers, sectionalizers, and line fuses.

TriAxis uses ASPEN Distriview to build a simplified circuit model for quick answers or to construct complex models with multiple sources, radial and looped lines, in normal and contingency configurations, for comprehensive studies.

Protective Device Coordination

Proper protective device coordination can prevent damage to equipment. At the same time, it can reduce both the extent and duration of system outages by sectionalizing the area of the trouble. TriAxis adds protective devices and their settings to the system software circuit model and examines the interactions and coordination of these devices. Protective device time current curves (TCCs) are produced to document the intended coordination of their operation.

Protective Relay Settings

In addition to examining existing system-wide protective device settings, TriAxis can provide recommendations for substation and switchyard relay setting changes, replacements, and complete sets of relay setting sheets for common protective relays. TriAxis has experience with Basler, ABB, Cooper, Siemens, and SEL relays. Where requested, TriAxis can prepare equipment-specific electronic settings files for use by clients.

Arc Flash Studies

Using ASPEN Distriview models, TriAxis has prepared both detailed and general arcflashstudies. Arc hazard assessments look at high-, medium- and low-voltage systems and the protective devices and working practices typically encountered. TriAxis has developed recommendations for arc-flash management programs and personnel protective equipment policies. TriAxis has also developed utility-specific hot-line tagging programs for use in protective relays to implement arc hazard reduction programs. Several industrial clients have had TriAxis perform detailed arc-flash hazard assessments for compliance with codes and standards. In some of these projects, TriAxis has used SKM software, at client request, when performing the studies. TriAxis has a license for SKM software.

Short- and Long-Range Capital Improvement Plans
TriAxis has provided clients with system studies that estimate and then examine the impacts of future load growth patterns, service area annexations, and general system expansion.

TriAxis can also perform studies to recommend cost-effective maintenance replacements, which improve system efficiency.

These studies always include much client input and collaboration to plan changes and mitigation strategies. To plan future capital needs, a Short- or Long-Range Capital Improvement Plan must be based on accurate construction cost estimates. TriAxis staff has extensive experience turning project concepts into constructed projects. We regularly provide order-ofmagnitude, budgetary, and construction cost estimates. Using our current construction pricing information, and the experience of staff, we find our estimates to be consistently in agreement with actual construction costs.

Electric and Magnetic Field (EMF)

TriAxis routinely performs power line Electric and Magnetic Field (EMF) analysis for project permit applications, Environmental Impact Studies, and Environmental Assessments. TriAxis has assisted numerous utilities, developers, and environmental/permitting consultants with the descriptive text, figures, and EMF analysis graphs for overhead and underground lines with voltage ratings from 12.47-kV to 500-kV. Our contributions to the power line sections of these documents normally include calculations of audible noise and radio/TV interference, in addition to EMF. Overhead line projects are often built in the proximity of existing lines. To present the “before and after” impacts, TriAxis models and analyzes the existing EMF levels, and then models and analyzes the configuration of existing facility with the proposed facility added. The calculations are summarizes in graphs for the Right-of-Way cross-section, and in tables for the closest receptors. TriAxis maintains two EMF calculating tools: Power Line Systems EMF Calculator Module, and Bonneville Power Authority “Corona and Field Effects” program. Because the BPA program provides corona effects, it is more often used than the PLS program.

Because the design of overhead lines is a core business for TriAxis Engineering, we are able to provide intelligent plain-language responses to review questions raised by permitting agency staff and their consultants.

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