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How software tools can help utilities with underground utility design

Steve Kearney
Enghouse Systems USA, Inc.
1301 Fifth Ave., Suite 1400
Seattle, Washington 98101


Topics of Discussion

This paper will cover some of the issues that are a concern for the electric and natural gas industry, and they are:
  • Deregulation is motivating the software market place to develop automated underground plat design tools that allow the designer to place equipment (such as cable, transformers, etc.), conduct engineering analysis on that design, and interface into AM/FM/GIS and Work Management systems;
  • More and more states (as well as the federal government) will enact deregulation legislation forcing compatition with utilities in each state as well as regions of the USA;
  • Distribution functions of utility companies must perform more tasks with less people and smaller budgets;
  • These software tools should have some type of "fuzzy logic" routines, to ensure that the underground designs use the least amount of cable and place transformers in the best location, and guarantee that the design in engineered with the "utility standards".
Automated Plat Design systems allow the utility to achieve a paradox in this industry: cutting costs while providing better service to their customers. There are two types of customers that the utility should be responsible to: the Developer of the subdivision that is being built, and the customer that will be living in the area being developed. The Developer is usually waiting on the utility company to design the infrastructure for the development. The Developer needs to know where the electrical and natural gas equipment will be installed, and if there are any cost associated with placement of those devices. Usually with Developers, they are also concerned with the "look" of the development. Providing the placement and the costs associated with automated software package will ensure customer service and well as performing designs that are engineered properly. Customers that live in the development will also be assured that outages will be reduced, as well as any voltage drop problems will be minimized.


Diagram 1 - Electrical Design of a Plat


What are Automated Software Tools for Underground Design?
Automated Plat Design tools are software developed for utility engineering personnel to design Underground Residential Distribution (URD) applications. This software combines Geographic Information System (GIS) platform with artificial intelligence (AI) to help designers to develop the most economic and technically optimal electric and natural gas distribution system. This software conducts the design process and generated design solutions from specification values introduced by the utility, during configuration into that utility's operations. Using the AI of the software, the designer can perform "What if" analysis by varying different design elements and comparing the results. The operator can also store different versions of a plat design, giving the designer the opportunity to compare costs, voltage drop, fault current, cable pulling tension, annual losses, load balance, natural gas performance (with combination utilities).

The first step in the process is to collect a dgn or dxf file from the Developer of the subdivision. Since around 90% of the subdivisions in the USA are drawn on AutoCADbased systems, this file can be easily obtained by the utility. Important information, such as lot lines and boundaries are collected and assembled, and imported into the design portion of the software. As the designer creates designs, the software provides immediate on-screen responses to the design layout, cost analysis, electrical performance, and gas performance. Several designs can be compared in much less time than it takes to create one design the old way - manually.

After the designer decides on the best plat, the design is exported into either a work management system or outputted directly into a staking sheet system. The plat design software provides the output of the graphics in either a dxf, shape file, dgn (for the AutoCAD version, or ArcInfo (for the ESRI version). The capable unit, which includes all of the material and labor of the design, is provided in an ASCII output.

Cost and Time Savings
Several independent utility studies have been performed in the last two years, showing at least a 15% reduction in construction cost since using the automated plat design tool. These studies have bench marked subdivisions that the utility constructed before the software was in place, versus the design of the same subdivision with the software being used. Studies have shown savings of $10,000 to $15,000 on design and construction of services for an average 100-home subdivision. The savings is achieved in two ways:
  • The software uses the utility's current "rules of tumb" and the AI that creates an initial design that is already close to optimal.
  • The software allows the designer to change individual or groups of parameters to test for even better performance, all the while keeping track of material and labor costs to construct each design.
Some of the cast studies can be found below. This chart identifies each utility by the state that they are located. The number of lot per year is the average number of lots that are developed by that utility per year. Annual savings can now be developed, without taking in consideration the initial investment of the software.

State Savings/Lot # of Lots/Yr. Annual Savings
Nevada $150/lot 25,000 $3,750,000
North Carolina $110 /lot 20,000 $2,200,000
Georgia $95 /lot 5,000 $475,000
California $105/lot 18,000 $1,890,000

Savings are also achieved with utilities that provide both electric and natural gas services. Electric system design is first accomplished, and then plat design software uses all of the trenches that were used for the electrical distribution and then designs the gas distribution using those trenches. Gas pipes are minimized because the electrical distribution is minimized by the software in the previous design. This also provides the utility a way to ensure that location of this equipment is maintained, and that installation crews do not interrupt or damage services when they are installed.

Future Enhancement
With the advent of electrical and natural gas design, the next step is to automate the design process for the other underground utilities (such as Telephone and Cable TV). Software companies are currently addressing, and collecting the expertise of these industries, to develop the algorithms to automate these processes. Using the existing trenches that were developed for the electrical system, the telecommunications infrastructure can be designed.

Summary
In summary, automating the process of designing and conducting the engineering analysis of URD subdivision will become a major concern for the distribution operation of utility companies. More and more, distribution operations will be forced to provide designs faster and more accurate to Developers. Costs, which include installation labor of the utility equipment (both electric and natural gas), will need to be reduced to a minimum while maintaining the operational integrity. Proven software tools are available today to automate these requirements. Some Plat Design tools have basic location of utility equipment, but few have artificial intelligence to completely automate these processes. Interfaces into AM/FM/GIS and Work Management systems are also a necessity for the software to work. Current technology allows for utilities to purchase these tools today.
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