Patent Publication Number: US-2005125204-A1

Title: Utility station automated design system and method

Description:
CROSS-REFERENCES TO RELATED APPLICATION  
      This application is related to, and claims the benefit of the earlier filing date of, U.S. Provisional Patent Application Ser. No. 60/128,560 (Attorney Docket 7910-0032-13 PROV), filed Apr. 9, 1999, entitled “Utility Station Automated Design System and Method,” the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention pertains to automated design systems and methods for planning and designing utility stations. More particularly, the present invention relates to automated design systems, methods and computer program product, for designing, and estimating materials and costs for utility stations, such as a unit substation or other component of a public utility system, such as an electric power generation, transmission and distribution system.  
      2. Discussion of the Background  
      In 1999, a typical unit substation design and development project costs approximately 1 million dollars and takes roughly one year from conception to completion. The typical process begins with an engineer who prepares a sketch of the substation, and sends the sketch to a drafting area, where a draftsperson takes the sketch, along with associated notes prepared by the engineer, and develops a working construction set (i.e., a set of drawings with associated symbols and notes). The draftsperson then gives a draft construction set to the engineer for review. At this time, during the review, the engineer would either modify the construction set, or add additional information to the construction set and then send the modified construction set back to the draftsperson for redrafting to incorporate the changes. The draftsperson completes the changes and sends the changes back to the engineer. This iterative process can repeat as many as four or more times. Once the construction set is finalized, roughly three or more months have expired since the initiation of the project.  
      As presently recognized by the inventors, the conventional design process presumes that every unit substation has to be redesigned by the engineer, even though approximately 90% of the components are the same between substations. In this way, the engineer has to address each component of the system, even though the engineer may have already done similar work on previous projects. After the initial design is done, the engineer then prepares a materials list of the components and prepares a cost estimate.  
      Regarding how the details are developed in the drawings, the Engineer is provided with a “one line diagram” from a planning department and includes an electrical representation of the symbols for each device to be included in the substation. Conventionally, draftspeople use CAD (computer aided design) programs, like AutoCAD, a draftsperson oriented program. The draftsperson then draws the component parts of the system using the CAD program. After a CAD drawing has been prepared, the engineer will provide the CAD drawing to the planning department, who at that time may decide to further modify the substation, so as to change components required therein, or change the system performance to meet perceived customer demands. If the planning department does change the drawings, another engineering and drafting operation is required in order to produce a final set of construction drawings.  
      These construction drawings are detail oriented, such that the drawings may be provided to a contractor for building the substation. For example, the construction drawings will have detailed features, such as conduit placement, foundation placement and grounding placement. The drawings also show the connections amongst the different subcomponents used in the substation. These connections can be very detailed, perhaps showing a small connector fitting between pieces of bus lines. This detail may become very cumbersome because a unit substation may have between two and three hundred electrical connectors. Furthermore, the unit substation may have three to four hundred feet of aluminum bus infrastructure, a couple thousand feet of copper in the ground, and on the order of 20 to 50 foundations. After the drawings are complete, the engineer then uses the drawings to fill out a materials list for the equipment to be ordered. Generally, it is a time consuming process for the engineer to scrutinize the different components on the drawing and list the same on a materials list.  
      As recognized by the present inventors, the iterative process between the engineer and the draftsperson is a time consuming process, and an expensive procedure for designing substations. The conventional process presumes that each substation has different characteristics that mandate the use of a significant amount of engineering, as well as draftspersons&#39; time in order to properly design the substation. However, as presently recognized, there can be a significant amount of redundancy between respective substations, that if, properly characterized could be an advantage in streamlining the design process.  
      Another limitation with the conventional practice, is that the iterative design process is prone to error, based on the number of different people involved in the process. Furthermore, because each substation is custom designed, it is more difficult for planning departments, as well as contractors who will build the substation to interpret the drawings because each set of construction plans differs from one substation to the next.  
     SUMMARY OF THE INVENTION  
      Accordingly, one object of the present invention is to address the above-described limitations of existing systems and methods. While the present section of this document is directed to a summary of the invention, a limited number of attributes associated with the present invention are described herein. However, a more complete description is provided in the section entitled “Detailed Description of the Preferred Embodiments”.  
      The present invention is directed to a utility station automated design system and method that allows an engineer to design a unit substation, or other utility station, as well as prepare a materials list and cost estimate, in several hours, rather than several months, as is the case with conventional design practices. A feature of the present invention, is a computer-based tool having a database that holds both standard “substation templates”, as well as equipment “symbols” that may be applied to one another, as selected by a user, via a graphical user interface to produce a 3D drawing set. The user is presented with a series of options that are logically arranged so as to guide the user through the process of designing the unit substation, using the symbols and templates, as selected by the user. Moreover, the user is requested to select a predetermined “standard” substation architecture, and once selected, the user is presented with a series of options regarding which components are to be included within the standard configuration. Once selected, symbols associated with the selected components, are selected by the user from a database, and overlaid in layers with the assistance of a computer aided drawing package. In this way, the symbols are arranged and presented on a display, or printed as a set of construction drawings, so that an overall unit substation system may be designed in a relatively short period of time. Subsequently, the user may be requested to identify whether the user would like to modify the existing design, or prepare a list of building materials and cost estimates associated with the respective components in the unit substation, or other utility station. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:  
       FIG. 1  is a block diagram of a computer network according to the present invention, that interconnects a user terminal, with a print server, and database server;  
       FIG. 2  is a flow chart of a process flow for designing a new 115 kV unit substation;  
       FIG. 3  is a flow chart of a process flow for modifying an existing substation facility;  
       FIGS. 4A and 4B  are a flow chart, showing a logical process flow, for either designing a new substation, modifying an existing facility, or preparing an estimate/material list;  
       FIG. 5  is a perspective view of a 3-D rendering of a substation that may be designed from drawings produced with the present invention;  
       FIG. 6  is a graphical user interface, showing a library of user selectable “symbols” that may be incorporated into a substation being designed;  
       FIG. 7  is a plan view of components included in a unit substation being designed;  
       FIG. 8  is a perspective 3-D rendering of the station shown in  FIG. 7 ;  
       FIG. 9  is an example display of a pull down menu, showing various options made available to a user when determining whether to design a new station, or modify an existing substation;  
       FIGS. 10A-10B  are respective display screens, showing different user-selectable components for inclusion in a substation; and  
       FIG. 11  is a display of a dialogue box, requesting information regarding a cost estimate and list of materials associated with the design of a substation. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to  FIG. 1  thereof, there is illustrated a utility station automated design system configured to allow a user to design a utility station, such as a unit substation, and prepare a drawing construction set, as well as a cost estimate and materials list.  
      Although the present invention is discussed with respect to design of a utility station, the approach, as recognized by one of ordinary skill in the relevant art, is applicable to other types of facilities, including water facilities as well as gas facilities. For example, the water facilities encompass wells/well houses, pump stations, lift stations, pressure regulator stations, complex piping arrangements, small to moderately sized water and wastewater treatment plants and site layouts, and tank sites. The gas facilities can be categorized as follows: transmission facilities, distribution facilities, and production and gathering facilities. These three types of gas facilities involve interconnects with other pipeline companies&#39; facilities, regulator (pressure reducing) stations, metering stations (e.g., delivery stations, border stations, and check meters), pressure and flow monitoring equipment, valve stations, and, compressor stations.  
      Before turning to the specific features contained within  FIG. 1 , an overview of a method and system implemented by the present invention is in order. The present invention was made in recognition of efficiency limitations with the conventional substation design processes employed in the utilities industry, where significant design times are expected for preparing unit substations (or other components of a public utility). Conventionally, significant amounts of time are allocated for a CAD manager and senior engineers, regarding preparation of construction sets (drawing packages that describe the unit substation). One of the limitations with the conventional approach was determined to be that each CAD operator had a different skill level and different ideas regarding how particular drawings should be laid out. This lack of uniformity regarding how the CAD operators interpreted the information provided by the engineers, resulted in inconsistent system configurations, and inefficient, iterative communications between the CAD operator and the engineer.  
      In light of such problems, the present inventors determined that it was possible to use AutoLISP routines that would be used to prepare menus to import different information regarding company information and like into the drawing set. For example, a feature of the invention is to use a AutoLISP routine to provide on a pull down menu, such as the size of the drawings, such as “A”, “B”, . . . , or the drawing scale. This routine also sets line types, text, layering, line widths and the like, so that respective drawing sets from a particular company, will be uniform in appearance.  
      Aside from importing corporate information into a particular drawing, the present inventors also determined that it would be advantageous and commercially efficient to prepare pre-approved two-dimension (2-D) symbols, or 3-D symbols as will be discussed, for an entire station of equipment, complete with foundations, conduits, and grounding at all voltage levels used by the corporation. Through the use of layer control in AutoCAD, each of the pre-approved and stored equipment symbols are placed in an equipment layer, the foundation symbols to be placed in a foundation layer and so on. In this way, symbols can be associated with a particular drawing, thereby allowing the user of the system to automatically specify the symbols (and the components associated therewith) to be automatically retrieved and overlaid on the drawing. In this way, when construction drawings are prepared, where construction drawings include a plan view, section view, conduit plan, grounding plan, foundation plan and the like, depending on the drawing type selected, the AutoLISP routine turns layers off and on until only the foundations are visible, if the foundation plan is the one that is to be displayed. Dimensioning work for the respective components shown in the drawing is done automatically with AutoCAD.  
      In an alternative embodiment, pre-approved and pre-drawn 3-D symbols are a substitute for, or are used with 2-D symbols. Using 3-D symbols, allows for not only perspective view, but also allows a user to change the viewer&#39;s reference point in 3-D. Furthermore, a 3-D model is automatically produced which is capable of being rendered. The 3-D renderings produced with the 3-D model can be used in governmental permit hearings. Typically, such work cannot be produced in the typical CAD facility, but rather are provided to an outside drafting firm, with both cost and time penalties associated therewith.  
      By saving the respective symbols in a library, accessible to different users, by way of the computer network, users may extract the respective symbols when designing a unit substation. So as to avoid having the end user, perhaps an engineer, become familiar with 3-D design practices, the present invention incorporates dialog boxes, hierarchically arranged, and AutoLISP routines that allow the user to design a 3-D structure from a plan view. In this way, the user can design the system, by providing only minimal information, regarding the size of the bus, bus spacing and the like, and the AutoLISP routine makes the additions to the drawing on the correct layers at the correct heights as a 3-D, custom model would do.  
      In view of the present inventors&#39; observations, much of the structure within a substation is, or at least could be, reused. The present inventors determined that aside from symbols, substation-level templates, (i.e., pre-approved substation layouts) may be used to preposition respective components within the substation. In this way, the engineer need not spend time positioning respective components, but rather needs to only select symbols, and have the symbols automatically placed in the pre-approved locations.  
      One feature of using components as part of a standardization design process, is to standardize different sizes of transformers to predetermined set levels. For example, in a preferred embodiment, three different top-ratings of transformers are used: 14 MVA, 22 MVA, and 33 MVA. Other ratings may be used as well. Furthermore, the standard unit substation also includes one of four types of switch gear: 2 feeder, 3 feeder, 4 feeder, and stations with a main breaker. To this end, in the preferred embodiment, different unit substation “templates” include three standard layouts, referred to herein as “single unit-right”, “single unit-left”, and “two unit designs”. Other standard layouts may be used as well, as will be appreciated by one of ordinary skill in the substation design art, based on the description contained herein.  
      An advantage of the present invention is that the respective symbols used within the substations have associated therewith different attributes which are stored in memory. These attributes are associated with symbols by file name, for example, and stored in one or both of ACCESS data files, and EXCEL spread sheets, where both ACCESS and EXCEL are available through Microsoft Corporation.  
      Using the system and method described herein, an engineer can produce a construction set of a unit substation in approximately 3 hours. The engineer reviews a description of the substation provided by a planning department and then initiates an AutoCAD session. The engineer then selects the type of drawing from the pull down menu presented on a display screen. Subsequently the engineer selects a type of station to be designed, such as a new 115 kV unit substation. Other types of stations or other differently rated substations may be designed as well. After selecting the type of substation, the engineer is presented with a series of dialog boxes, logically arranged in sequence, for presenting choices regarding the components to be used in the overall system. The engineer responds to the respective prompts, and the responses are saved in memory. Once all the entries are complete, the engineer executes a compilation routine by acknowledging the engineer has made all of the selections, and AutoCAD begins to draw the station, by retrieving the pre-drawn symbols from a library and applying the respective symbols to the selected pre-designed substation template. Subsequently, the engineer can request, or as an alternative the request may be automatically produced, to provide a cost and estimate materials list for the materials needed for the construction of the unit substation. Thus, rather than taking three months or more to produce the construction set, the engineer can complete the job, reliably and efficiently in approximately three hours.  
      Turning to  FIG. 1 ,  FIG. 1  is a block diagram of a utility station automated design system according to the present invention. In particular, a network  90  is included, such as an Ethernet, FDDI network, Intranet or Extranet, at least a portion of which may be an Internet connection or a public switch telephone network (PSTN) connection. The network  90  allows a general purpose server  100 , as well as an AutoCAD server  120  and a print server  133  to communicate with different user stations  140  and  150 . The general purpose server  100  includes a memory  105  that hosts application software, such as EXCEL, ACCESS and the like. The application software hosted on the memory  105 , is accessible via the network  90  by each of the user terminals  140  and  150 . The general purpose server  100  also includes a monitor  103  and computer  101 , with a CPU, internal memory, peripheral devices, internal communication bus, RAM and ROM memory, and the like contained therein.  
      The AutoCAD server  120  includes a memory  126  that includes the AutoCAD application, custom menu structure, custom macros, custom list routines and custom symbols, as were discussed above. Information produced at the computer  122  may be viewed on the display  124 , or alternatively other information provided via the computer  122  is viewed on the display  124 . The print sever  130  includes its own computer  132 , and display  134 . The computer  132  contains a communication mechanism that communicates over the network  90  so that information may be passed to a plotter  136  for producing hard-copies of drawings sets. User workstation  140  includes a computer  142  and monitor  144 , where the computer  142  communicates via an input/output (I/O) device  146  for communicating with external devices. The external devices may be remote terminals, or even local peripherals, such as a mouse, keyboard, external memory and an interface for loading symbols if necessary and the like. Similarly, user terminal  150  includes a computer  152 , monitor  156 , and I/O device  154 .  
      As part of the AutoCAD server memory  126 , the present invention includes a database of custom symbols, where each of the symbols are 3-D drawing files of components used in a unit substation. Held in the ACCESS database and/or EXCEL spreadsheet in memory  105 , are attributes that are associated with the custom symbols held in the database of symbols in the memory  126 . In addition, AutoLISP routines perform the functional operations interfacing function for communicating with AutoCAD, and thus perform the separate processing steps described herein. These AutoLISP routines are also contained in the memory  126 . Furthermore, both the menu arrangement as presently discussed herein, as well as macros, that help to assist in performing routine repetitive operations are also stored in the memory  126 .  
      Typically, a user will design a substation from one of the user terminals  140  or  150 . In the embodiment described in  FIG. 1 , the user terminal retrieves the information from the general purpose server  100 , and AutoCAD server  120  as required. Alternatively, all of the components and software may be contained on one workstation or computer, so that no network is required and all work may be performed locally. As a further alternative, additional external computing devices may be used as well to perform some or all of the computations and routing of information. In these cases, external communication links, such as through the public switch telephone network, Internet, or even proprietary wireless and wired links may be used as well.  
      The AutoCAD application included in the memory  126 , may be AutoCAD 2000, although other versions of AutoCAD may be used as well, such as AutoCAD release  14 , the on-line help section documentation for which is incorporated herein by reference.  
       FIG. 2  is a flowchart, showing a process according to the present invention for designing a new unit substation. The process flow shown in  FIG. 2 , corresponds with the top horizontal row of operations shown in  FIG. 4 , as will be discussed later. In  FIG. 2 , the process begins in step S 1 , where the user launches the AutoCAD application. The process then proceeds to step S 3 , where the user selects, via a pull-down menu, that the user would like to implement a 3-D layout/equipment operation. In step S 3 , the user may then use sub-menus to select a new standard 115 kV unit substation from a pull-down menu, as shown in Step S 13 . On the other hand, also shown in the pull-down menu, is the option for the user to select an estimate/material list operation from a pull-down menu in step S 15 . Each of these steps will be discussed in more detail below.  
      If the user selects to design a new standard 115 kV unit substation, or other station as preprogrammed into a set of templates, the user selects this option. The process then flows to step S 5 , where the user is presented with a design dialog box associated with a “template” 115 kV unit substation. An example of the dialog box is shown in  FIG. 10A  where a series of information prompts is presented for the user to select components of the 115 kV design. Each of the respective selections are shown in  FIG. 10A . Before entering the details of the 115 kV design, the respective voltages used, in a preferred embodiment are discussed herein.  
      At a generation plant in the U.S., generators typically generate approximately 22,000 volts. This voltage is then stepped up to approximately 345,000 volts for cross-country transmission. This high voltage is used in order to minimize resistive losses. However, the 345 kV is too high for use in end use applications, and therefore the voltage is stepped down to 115,000 volts in some cases, where the 115,000, as well as the 345,000 volts are all three phase voltages. The unit substation converts the voltage from 115 kV down to 12,470 volts. The 12,470 volts then is distributed around cities and the like and connects to transformers that hang on utility poles in residential areas, for example. It is these transformers that converts the electrical power down to the 120-240 volts used in the United States and typical applications. While the present discussion has been directed towards power distribution in the United States, the particular numbers herein, may be adjusted for use in other countries around the world.  
      Returning to  FIG. 10A , the engineer after identifying the project name and other information associated with the project, selects a template regarding the type of substation selected. The type of substation may either be a single unit design-left, single unit design-right, two unit design, or a unit designed with a 115 kV breaker. Other templates describing other arrangements may be used as well. After selecting the substation template, the engineer may then select the top rated MVA, a measure of apparent power.  
      The engineer then selects the ground grid spacing, from a predetermined set of spacings, as shown. Subsequently, the engineer selects the wall height surrounding the substation, swing grill, fixed grill, and mandoors. After all the selections are made, the operator clicks the “OK” button to complete the selections. Once clicked, the selections are saved in memory.  
      The above discussion was directed to step S 5  in  FIG. 2 , and after this step, the process proceeds to step S 7  if the user desires to make design selections for the switch gear associated with the substation. The reason why the switch gear is made into a separate dialog box, is that the switch gear may have some unique features in it depending on the operational goals of the substation. Accordingly, standardization of the substation is made separate from that of the switch gear, so as to maximize the flexibility for the engineer when designing the substation. Switch gear selections may also be incorporated into the substation component selections. An example of the dialog box which is displayed in step S 7  is shown in  FIG. 10B . In  FIG. 10B , the different number of feeders, shown in left and right configurations, are provided as well as the switching gear options as shown. While the number of feeders is shown to be 2, 3 or 4, it is possible also to include a greater number of feeders, such as for a 30 MVA system. Greater or lesser number of feeders than that displayed are available for use in the present invention. After the user has selected all the options in  FIG. 10B , the user clicks the “OK” button and the process proceeds to step S 9  in  FIG. 2 .  
      Switch gear is a disconnecting device and a metering device. Power is brought in from the transformer into the switch gear and then has feeders that extend therefrom into separate circuits. Disconnecting devices, such as circuit breakers, are included on each circuit. In this way, it is known how much power is being used on each of the feeders, by way of the meter. Each of the circuits are thus separately protected and this control and monitoring of the respective circuits may occur independently, so that if lightening, for example, were to hit one of the feeders, then that event would be detected and the feeder may be disconnected without damaging the other feeders.  
      Information that is input by the engineers in the respective dialog boxes is collected by way of a AutoLISP routine that takes the respective choices, compiles the choices and takes the compilation of choices to an associative mechanism, that retrieves respective symbols from the symbol library in the memory  126  for retrieval. Once the symbols are retrieved, the symbols are then overlayed in a drawing, as is the case in step S 9  as shown in  FIG. 2 .  
      In  FIG. 2 , after step S 9 , the process proceeds to step S 11 , where a 3-D model of the unit substation and construction drawings are created and printed out, based upon whether the user selects to create the hard copy of the drawings at that time. The hard copies are printed by way of the print server  130  on the plotter  136  of  FIG. 1 . The drawings may also be sent electronically to a remote location, such as a government facility for review and approval.  
      In  FIG. 2 , once the drawing set has been created, the operator has the choice of proceeding to step S 15 , from S 11 . Alternatively, the operator may proceed directly to step S 15 , by way of step S 3  as previously discussed. In step S 15 , the user selects from a pull-down menu the estimate/materials list operation. When selected, another AutoLISP routine extracts the attributes associated with the selected symbols from the ACCESS database. In this way, the attribute information may be sent to a template file for presentation to the end user in a materials list. Another AutoLISP routine takes the information that has been extracted, launches the EXCEL program and passes the information in a text file that has been taken from AutoCAD to EXCEL where the template accepts the information and presents it in an EXCEL compatible format. When extracting the information, the attribute information that was taken from AutoCAD perhaps may be representative of multiple components, but the template recognizes the multiple components as a group, and therefore can present the materials list and cost estimate in a cohesive manner. Thus, extraction involves an identification of the components and then based on the components identified, the attribute information associated with those components is retrieved, as previously stored in ACCESS or even EXCEL. This code extraction process is shown as step S 17  in  FIG. 2 . The output of step S 17  is a hard copy of an equipment list and cost estimate, based on the different components included in the substation, as designed.  
       FIG. 3  is a flowchart describing a method for automatically modifying a pre-existing utility station, such as a substation. The process begins in step S 100  where the AutoCAD application is launched. The process then proceeds to step S 101  where a selectable menu presents options for modifying an existing facility (step S 103 ), or for selecting 115 kV equipment from a particular pull-down menu, as indicated in step S 113 . If the user elects the path of the step S 103 , the process then proceeds to step S 105 , where the user is presented with a dialog box requesting information regarding the pre-existing drawing set to be modified. The process subsequently proceeds to step S 107 , where the existing AutoCAD drawing is located and loaded externally as an XREF, an externally referenced file. This XREF file may not be modified, but new components may be added thereto. The process then proceeds to step S 109 , where the drawing set is created. If however, the operator selects the path of S 113 , after performing step S 101 , the process proceeds to allow selection or modification of unit and sub-switching station symbols according to modifications made by the user. The process then proceeds to step S 109 , discussed above.  
      From either step S 101  directly, or from step S 109 , the process proceeds to step S 115  and then step S 17 , which performs similar operations to those described in step S 15  and step S 17  of  FIG. 2 . Subsequently, the user has the option of making a hard copy of the drawing set.  
       FIGS. 4A and 4B  provide a logical flow diagram for the respective menus, macros and AutoLISP routines performed by the present invention. The respective boxes are color coded, as seen, indicating whether the respective steps in the process are pull-down menu items (dark blue), sub-menu items (lighter blue), menu macro operations (purple), dialog boxes (grey), AutoLISP routines (yellow shaded), or an EXCEL spreadsheet (yellow). The process begins in step S 400  where the application is started and then the process proceeds to step S 401  where a 3-D equipment layout/equipment pull-down menu is presented. An example of this pull-down menu is shown in  FIG. 9 . Respective steps S 403 , S 413 , S 419 , S 423 , S 427 , S 443 , S 451 , S 457 , S 465 , S 475 , S 485 , S 487 , S 497 , S 553 , S 557 , S 563 , and S 571 , are steps that are accessible by way of the pull-down menu presented in step S 401 . For clarity purposes, only selected steps in  FIGS. 4A and 4B  are discussed herein, as it is believed that the logical process flow and labels provided on the respective labels as well as the arrows indicating the logical process flow for the process is clear.  
      The process proceeds from step S 401  to step S 403 , when the user selects the menu item “New Standard 115 kV Unit Sub”. Then, as previously discussed, the process proceeds to step S 405 , where the user is provided with a dialog box identifying the different items that may be selected by the engineer. At this point, the operator has the option of going directly into the estimate operation which is performed in step S 409 , that provides the dialog information that is extracted to a text file and provided to the EXCEL spreadsheet. On the other hand, if the process proceeds from S 405  to step S 407 , the switch gear design dialog box is presented to the user, for component selection by the user. Subsequently, the unit substation routine S 14  is performed, where as previously discussed with respect to  FIG. 2 , the substation is designed based on the standard templates and prestored symbols, which were identified by the user in the dialog boxes presented in steps S 405  and S 407 .  
      In step S 413 , the operator indicates that the operator would like to modify an existing facility, and is presented with a dialog box in step S 415 , which receives input from the user, and provides that information to the estimate dialog information in step S 409 , and updates the information contained in the drawing set, in the exist routine S 417 .  
      Each of the remaining steps in  FIGS. 4A and 4B , follow a consistent pattern, where depending on the feature to be included in the drawing set, the operator simply selects one of the items from the 3-D sub-menu items listed on the left-hand side of  FIG. 4B . In each case, the process then performs a logical flow to other routines, selections, as well as dialog boxes, for identifying symbols associated with the particular feature to be included in the substation design, and then presented as part of a cohesive drawing package, as was the case with the complete design process previously discussed. As the features and labels of each of the other elements are believed to be clear to one of ordinary skill in the power engineering art, and particularly in the unit substation design art, further discussion of the information contained in  FIGS. 4A and 4B  is not believed to be necessary, particularly when interpreted in light of the complete description provided herein.  
       FIG. 5  is a 3-D perspective view of what a typical substation may look like after being built from the construction drawings made with the system and method of the present invention.  FIG. 6  shows examples of particular symbols, contained within the symbol library, as previously discussed. In a 3-D rendering of such a substation, according to the present invention, a plan view of similar structure is shown in  FIG. 7 . A perspective view of the substation shown in  FIG. 7 , is also shown in  FIG. 8 . For each of the system components shown in  FIGS. 7 and 8 , corresponding attributes for the components are used to form the materials list and cost estimate, as previously discussed. Furthermore, symbols for the respective components have been saved in the symbol library.  
       FIGS. 9 and 10 A- 10 B have previously been discussed.  
       FIG. 11  is an exemplary dialog box that would be presented to a user, prompting the user for information regarding the preparation of the materials list and cost estimate associated with the substation designed according to the present invention. A description of how the estimate program operates is provided on pages A-1 through A-38, which follow the Abstract. These pages are then followed by pages A-39 through A-44, which present supplemental information.  
      The processes set forth in the present description may be implemented using a conventional general purpose microprocessor programmed according to the teachings of the present specification, as will be appreciated to those skilled in the relevant art(s). Appropriate software coding can be readily prepared by skilled programmers based on the teachings of the present disclosure, as will also be apparent to those skilled in the relevant arts.  
      The present invention thus also includes a computer-based product that may be hosted on a storage medium and include instructions that can be used to program a computer to perform a process in accordance with the present invention. The storage medium may include, but is not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, flash memory, magnetic or optical cards, or any type of media suitable for storing electronic instructions.  
      Obviously, numerous modifications and various of the present are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.