Research Activities

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The DSTAR Approach to  Distribution Software

Distribution engineering is dominated by many routine functions, which must be accomplished quickly and efficiently.  Often these tasks are performed by technicians, designers, or engineers who are not analytically oriented. There are many power engineering software products on the market which are complicated and require significant training to use.

General-purpose Windows^® based software tools, such as word processors and spreadsheets, have become pervasive throughout the business environment.  Users have come to expect a user-friendly graphic interface for performing their tasks.  However, easy-to-use software tools dedicated to routine distribution engineering tasks, using modern user interfaces, are not generally available.  Much of the distribution engineering software used in the industry is older DOS-based or mainframe applications.  Many have fallen in disuse because they do not meet the modern expectations of ease-of-use.  There are some engineering workstation software suites available, but often these are quite complicated and require extensive expertise and training  for their use.

To meet the need for modern engineering software tools, DSTAR has developed a number of  Windows^® based applications which are designed to be used with minimal training. These applications can be easily customized to the materials and practices used by each member utility, allowing the ultimate user (for example, a design technician with limited engineering expertise) to apply the program with maximum efficiency and minimum complexity.
 

Software Programs

The following software has been developed and delivered as part of the indicated DSTAR programs (or is presently under development, as indicated)
 

This powerful program evaluates transformer total owning costs, including the economic effects of loading on transformer life. Hour-by-hour thermal modeling is performed. A companion application, the TOCS Optimizer, performs advanced optimization using TOCS results to specify loading ranges for transformers, optimize transformer procurement with a limited first-cost budget, and optimize transformer kVA ratings maintained in stock. For more information on TOCS, click here. Request Demonstration
 

The Cold Load Pickup software estimates a time duration versus current curve for a feeder at restoration following an outage. The estimation is based on the composition of the loads on the feeder, the duration of the outage, and the ambient temperature. For more information on Cold-Load Pickup, click here.
 

It is often desirable to apply transformers with unequal characteristics in a three-phase bank, construct three-phase banks with two transformers in the open delta-delta and open wye-delta configurations, or to apply unbalanced loads to three phase transformers or transformer banks. The resulting voltage imbalance can require derating of three-phase motors. The Graphic Secondary Voltage Imbalance Calculator performs these voltage imbalance calculations and determines motor derating, as well as phase voltage, currents, and transformer loading. For more information on GSVIC, click here.
 

The Toolbox is a collection of programs supporting routine overhead and underground distribution engineering calculations. Each tool is Windows-based, with graphic user interface. The toolbox includes:
Guy Tension Calculator
Transformer Loading Analyzer
Overhead Line Mechanical Analysis (Wind Loading, Sag, Blow Out)
Underground Cable Pulling Tension
Voltage Drop and Flicker
 

The Cable Electrical Parameters Software (CEPS) provides convenient calculation of underground cable parameters. A highly graphic user interface allows easy usage. The user specifies the cable construction (conductor size, stranding, insulation parameters, neutral type and design, etc.), as well as the cable installation parameters (duct spacing, duct size, trench width, etc.), and CEPS determines a wide range of cable electrical and physical parameters, including impedance, charging current, losses, voltage regulation, short-circuit current capability, and overall dimensions. For three-phase cable runs, the program also calculates impedances where a separate neutral conductor is installed. CEPS presently covers primary cables with concentric , drain wire, tape shield, and longitudinally corrugated neutral constructions. In addition, it can calculate parameters for secondary cables, and three-phase PILC primary cables. It is presently being expanded to add ampacity for directly buried cable, cable-in-conduit, and duck-bank configurations, as well as ampacity for cable risers in U-guard and conduit. Click here to view more details of CEPS. Request Demonstration
 

DSTAR research has shown that distribution cable derating is necessary when a cable crosses an external heat source, such as another cable or a steam main. Derating is also needed if the cable is in parallel with an external heat source for even a very short distance, such as the section where incoming and outgoing cables share a trench or duct bank for the distance between a cable right-of-way and padmounted transformers or switchgear. An Excel application, XDERATE, has been developed to calculate cable temperature increases due to these short-distance external sources. The temperature increase is then used in a conventional ampacity program to calculate the maximum load that the cable can safely carry. For more information on Cable Ampacity, click here.
 

The Secondary Electrical Design Software allows a designer to efficiently select a transformer and perform electrical design for a radial secondary system to serve multiple residential loads. The program calculates voltage regulation, cable and transformer loading with coincidence factors applied, voltage flicker, and short-circuit currents. For more information on SEDS, click here. Request Demonstration
 

The SCRAP program analyzes the losses, replacements costs, and remaining life of existing transformers to determine the maximum viable expense for rehabilitation of these transformers when they are taken down and returned to the utility transformer shop. For more information on TS/RDS, click here.