Abstract:
A computer-implemented method is provided for creating a peer unit and comparing that peer unit to a target unit in order to determine the difference in performance between the target unit and a peer unit. The peer unit is a hypothetical construct of user-defined performance variables whose values are determined based on outstanding performing units in a user-defined group. This comparison allows the user to assess what parameters of the target unit should be changed in order to improve overall performance.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 60/926,468, filed Apr. 27, 2007, which is incorporated by reference in its entirety. 
     
    
     BACKGROUND 
     1. Field of the Invention 
       [0002]    The invention relates to a system and method for comparative operational performance analysis using computer software for business and facilities, such as electrical power generating stations, manufacturing plants, and distribution centers, that enables quantitative benchmarking and probabilistic gap analysis for user-defined variables. 
       SUMMARY 
       [0003]    A method enhances benchmarking by adding the ability to dynamically benchmark unit performance with a software tool and database configuration that also has the functionality of monitoring and analyzing several key performance indicators. The benchmarking function determines the leading performers of a user-defined dataset and then computes the differences in the desired variables between a hypothetical best performer and the selected units. 
         [0004]    A computer-implemented method of comparing an output variable value of a target unit with a corresponding output variable value of a peer unit comprises the steps of: (a) determining a value of a first composite performance variable for a base unit, wherein the base unit meets at least one predefined parameter, comprising the steps of: performing a non-linear optimization with at least one constraint, wherein a first composite performance variable comprises: at least one base unit input variable; (b) determining a value of a second composite performance variable for the plurality of base unit, wherein the second composite performance variable comprises: at least one base unit output variable; (c) selecting at least two outstanding base units dependent on: the value of the first composite performance variable, and the value of the second composite performance variable; (d) determining a peer unit based on all outstanding base units, wherein determining a peer unit comprises: calculating output variable values for the peer unit based on the output variable values of the outstanding base units; (e) selecting a target unit for comparison to the peer unit; (f) selecting an output variable value for the target unit that corresponds to an output variable value for the peer unit; and (g) comparing the output variable value for the target unit with the corresponding output variable value for the peer unit, wherein steps (a), (b), (d), and (g) are performed by one or more computers. In another method the target unit is an outstanding base unit. 
         [0005]    A system comprises: a server, comprising: a processor, and a storage subsystem; a database stored in the storage subsystem comprising: unit operating data; a computer program stored in the storage subsystem, when executed causing the processor to: (a) determine the value of a first composite performance variable for a plurality of base units, wherein the first composite performance variable includes at least one base unit input variable, and wherein the computer program when executed causes the processor to perform a non-linear optimization with at least one expert constraint; (b) determine the value of a second composite performance variable for the plurality of base units, wherein the second composite performance variable includes at least one base unit output variable; (c) select at least one outstanding base unit dependent on: the value of the first composite performance variable, and the value of the second composite performance variable; (d) determine a peer unit based on all outstanding base units, wherein the executed computer program causes the processor to: calculate output variable values for the peer unit based on the output variable values of the outstanding base units; (e) select a target unit for comparison to the peer unit, wherein the target unit may be an outstanding base unit; (f) select an output variable value for the target unit that corresponds to an output variable value for the peer unit; and (g) compare the output variable value for the target unit with the corresponding output variable value for the peer unit. In another system, when executed, the computer program causes the processor to perform a non-linear optimization with at least one constraint. In yet another system, the target unit is an outstanding base unit. 
         [0006]    Methods may use a database that contains unit level data for generating a comparison. In the area of power generation, typical data for generating units would relate to design, location, fuel, technology, and performance data. The data is organized in the form of variables that contain performance information or behaviors and characteristics that correlate with performance in some way. For example, an input or cause variable may be the number of engine starts for a generating unit since the number of engine starts correlates with engine performance and maintenance costs over the life of the generating unit. While maintenance costs and engine performance factors (such as $/MWH and heat rate) may be output or effect variables. 
         [0007]    Another method utilizes a dynamic software platform where users enter data on a regular basis and use the software on demand to analyze, benchmark, and compare results of their units relative to other similar units. The user dynamically specifies the comparative performance database by completing the selection criteria screen and also enters the unit(s) identification number(s) that identifies the units to be benchmarked. This type of quantitative benchmarking enables the user to dynamically set up comparative performance analyses. The comparative performance is measured from the range, and the peer unit performance is determined from units selected for benchmarking. The results of the internal non-linear optimization analysis and probabilistic gap calculations are shown to the software user as part of the software&#39;s functionality and graphical displays. 
         [0008]    The steps in the methods, and system elements disclosed and claimed herein, as applicable, can be performed by a single entity or multiple entities, on a single system or multiple systems, and any and all method steps and system elements may be performed or located in the United States or abroad, all permutations of which are expressly within the scope of the claims and disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    These and further features will be apparent with reference to the following description and drawings, wherein: 
           [0010]      FIGS. 1   a  and  1   b  are a flow chart of the comparative analysis method; 
           [0011]      FIG. 2  is a diagram of the preferred embodiment of the system that enables the performance comparison analysis method; 
           [0012]      FIGS. 3   a  and  3   b  are a flow chart of the preferred embodiment of the method; and 
           [0013]      FIG. 4  is a list of variables from the IEEE Standard No. 762 “Definitions for Use in Reporting Electric Generating Unit Reliability, Availability and Productivity” available for user selection in the system and method disclosed herein. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Unit is broadly defined as a distinct entity. The term unit may refer to a single unit within a larger group, such as operating entities within a facility or business setting. Examples of units include electric power generators, chemical reactor vessels, pharmaceutical production lines, and package delivery centers. 
         [0015]    With reference to  FIGS. 1   a  and  1   b , in an embodiment of the method, users are able to enter information about units into the database, which helps keep information current for all users to perform comparisons. This embodiment of the method includes the set up of a series of input and output variables to provide comparison information to the users step  2000 . The variables used may be configured by the user, but will more typically be configured by an analysis controller. 
         [0016]    The user specifies one or more target units for comparison with a peer unit that will be determined by this embodiment of the method. The target unit data may be input by the user or existing unit data may be selected by using a unit identifier step  2000 . 
         [0017]    The database is flexible enough to allow the user to select comparison units based on a single characteristic, multiple characteristics, or simply all units. For example, power generation units could be selected by a performance characteristic, such as power generating capacity, and a characteristic unrelated to performance, such as a geographic region step  2010 . 
         [0018]    After the user selects the range of units for comparison step  2010 , the units that meet the selection criteria are selected step  2020 . The selection of units may involve the identification of unit data for processing or the extraction of unit data from the database to a processing module. Once a set of units are selected, input and output variable data for the selected units may be used to calculate the value of a composite performance variable used to predict performance (based on the input variables) steps  2020 ,  2030 , and  2040  and the value of a composite performance variable used to describe actual performance (based on the output variables) step  2050 . 
         [0019]    The composite performance variable used to predict performance (CPV p ) is calculated using non-linear optimization analysis methods and the input variables for the selected units to determine a value that represents the anticipated performance of each unit step  2030 . In a more preferred embodiment, the non-linear optimization is modified using professional expertise in benchmarking to safeguard the optimization process and to prevent erroneous CPV p  values step  2040 . This professional expertise includes but is not limited to placing maximum and minimum limits on the coefficients and exponents determined during the non-linear optimization process. The CPV p  value for each unit is calculated using the summation of the input variable value for that unit after applying coefficients and exponents determined during the non-linear optimization, and other mathematical functions as necessary step  2050 . For example, a CPV p  calculation may be CPV p =ΣC x (ln(I x )) Ex , wherein I x =the series of input variable values for a selected unit, C x =the series of coefficients for the input variables, and E x =the series of exponents for the input variables. This depiction of the CPV p  calculation is illustrative and exemplary only, and other non-linear optimizations techniques may be used to develop the CPV p  values for a unit. 
         [0020]    The composite performance variable used to describe actual performance (CPV a ) is calculated using mathematical functions designed to determine a performance rating for a unit with a given series of output variable values step  2060 . The CPV a  may involve several equations that allow individual performance characteristics to be weighted and combined into a single composite value. 
         [0021]    After CPV p  and CPV a  values for each selected unit, also known as a base unit, are determined, the outstanding performing units are selected based on the formula: OPV=(CPV p −CPV a )/(CPV p ), wherein OPV is the outstanding performance value variable step  2070 . Units with the lower OPVs are performing better than units with higher OPVs based on the current configuration of the comparative performance system. Outstanding performing units are interchangeably herein also referred to as outstanding units or outstanding base units. One or more outstanding units are selected based on their OPVs step  2080 . If a single outstanding unit were selected, then a comparison between one or more target units and the outstanding unit would be a comparison with best of breed. However, when there is more than one outstanding unit selected (such as the best three units, the worst three units, or units in a predefined range (e.g., second quintile)), then the output variable values may be averaged for the outstanding units to establish a “peer unit” step  2090 . In this embodiment, the term “peer unit” refers to a hypothetical unit composed by averaging the performance measures of outstanding units, except when there is only one outstanding unit such that the peer unit would be an actual unit. 
         [0022]    Next, confidence intervals are calculated for the peer unit&#39;s output variable values (which are the averages of the output variable values of the outstanding units) step  2100 . The confidence interval size is configurable and is determined using various techniques known to those of ordinary skill in the art. For example, a 95% confidence interval may be determined by using a student T-distribution. 
         [0023]    After the percentile confidence intervals of the averages are computed. The difference between a target unit&#39;s performance values and percentile confidence interval represents the probabilistic estimate for the performance gap step  2110 . This range is an estimate of the amount of reduction or increase, depending on the particular variable, that needs to be closed in order to achieve the desired performance levels. The technical details of how to close the identified gaps may be developed by those skilled in the art of particular type of units being analyzed. 
         [0024]    The gaps may be defined as a percentile range, e.g., 95% confidence intervals, since in practice, there can be several practices that achieve efficient and reliable performance and consequently, a range represents a more realistic result than a single value number. However, care should be exercised in the analysis of the identified mathematical gaps to ensure they can be reduced in a safe and prudent manner and achieve the desired long-term improved operational performance. 
         [0025]    As shown in  FIG. 2 , one embodiment of the method can be used for power generation benchmarking and gap analysis. This depiction of the system to support the method is illustrative and exemplary only. Operational and cost data for generating units where the design characteristics are known at a level of granularity consistent with the analysis goals serve as the basic inputs for the system. Cost data  100  include monies for operations, fuel, maintenance, and capital improvements in this embodiment. The data are consistent with the level of detail available in the reliability data (e.g., components, subsystems, systems and unit) and with the granularity of the reported reliability data (i.e., monthly). The use of reliability data is illustrative and exemplary only, as this method may use other types of data additionally or in place of reliability data. 
         [0026]    The operational availability data  200  are composed of event and performance information. The event database is a detailed summary of the outage and derating events each unit had during any given period. Summarized on a monthly basis, the performance database includes capacity ratings, generation, loading modes, availability and unavailability hours, and fuel quality information for each unit. 
         [0027]    The Generating Unit Design  300  database consists of details on the design parameters and installed equipment on each unit. The division of data into various databases is illustrative and exemplary only. 
         [0028]    The integrated data are stored in the database  400 . This database serves as the primary data source for all calculations and analysis. It is accessed by an analysis controller  500  that coordinates what specific calculations are requested by the user. The roles of analysis controller and database manager may be performed by the same person. 
         [0029]    The analysis modules in this embodiment include reliability data analysis reports  600 , which lists the desired reliability metrics in a user-specified format. 
         [0030]    The export options module  700  enables users to transfer data and reports from this system to other user-specified systems for extended analyses. 
         [0031]    The Reliability Data Analysis module  800  computes user-specific summary metrics and indices including but not limited to monthly, period average, or period total unitized cost data ($ per kW or per MWh) and reliability measures for the peer-unit group that includes the target unit(s) only, the peer-unit group including the target unit(s), or the peer-unit group excluding the target unit(s). 
         [0032]    The Graphical Frontier Analysis Module  900  enables users to review various strategies assists the decision-making process in setting realistic unit performance targets based on data from actual achieved performance by units in the comparison analysis as selected by the user. 
         [0033]    The Benchmarking &amp; Gap Analysis module  1000  enables users to utilize the cost data  100 , the operational availability data  200 , and the generating unit design data  300  resident in the database  400  to additional quantitative comparative analyses. As shown in  FIGS. 3   a  and  3   b , the user selection specifications are in several steps. 
         [0034]    In step  1005 , users select the performance benchmarking criteria based on size, time period, load type, unit type, and other design and performance data  1005 . This criteria defines the peer-unit group that, for example, may have similar design characteristics and operational parameters of the target unit to the experience data contained in the database. 
         [0035]    In step  1010 , users select one or more target units to be benchmarked. 
         [0036]    In step  1020 , users select from a detailed list, the variables to be benchmarked and performance gaps measured. This list, in one embodiment of the invention, could include the variables listed in the  FIG. 4  whose definitions are listed in the IEEE Standard No. 762 “Definitions for Use in Reporting Electric Generating Unit Reliability, Availability and Productivity.” 
         [0037]    At step  1025  peer group, target unit and variable data are extracted. This process is managed by the web service interface in  1030 . This interface performs functions related to data security and information management between the database and the family of independent users. Via web service, database queries are performed on the database  1035  to select only those unit records that satisfy all of these criteria and the results stored for additional analyses. 
         [0038]    The method internally computes the actual standardized operational analysis ranking variables from the database. This calculation involves the summation of standardized variables relating to heat rate, operating expenses, reliability and potentially other quantities  1040 . Using non-linear optimization analysis methods, a predicted standardized operational analysis ranking variables is computed from a nonlinear combination of the input variables: unit starts, operating factors, boiler pressures, unit size, and additional service-related variables  1050 . These input variables are illustrative and exemplary only. 
         [0039]    In step  1060  all units in the peer group are ranked from smallest to largest difference: ([predicted−actual]/predicted) standardized operational analysis ranking variables. The difference values are a measure of performance. 
         [0040]    In step  1070  the method selects the best performing units as those with the smallest gaps. The number to be selected is fixed to the user but may vary depending on the application. In this embodiment, the best performing group is chosen to be composed to the three smallest gap units. 
         [0041]    In step  1080  the benchmark variables selected in step  1020  are weight-averaged by unit power output, in this embodiment, to determine a point estimate value for best performance of the user-defined peer group. The point estimates are then applied with other standard statistical methods to compute a percentile range, e.g. 95%, confidence interval around the mean point estimate to determine a range that is taken as best performance. In this embodiment a 95% confidence interval is generated using a student T-distribution, however, this is illustrative and exemplary only. 
         [0042]    In step  1085  the difference between the best performance range and the specific values for the target unit(s) variables are computed. These ranges constitute the performance gaps between the target unit(s) and best actually achieved performance as computed in step  1080 . 
         [0043]    In steps  1090  and  1095  the gap ranges for all selected variables are displayed with detailed references to the peer group and the target unit characteristics are listed in tabular and/or graphical form. 
         [0044]    This system and method is a dynamic framework that enables users to continuously select new analysis situations, re-analyze and re-compare their units&#39; performance. The statistical and graphical presentations in steps  1090  and  1095  are important parts of the method that enables users to view and understand the results and then re-select and thereby refine, their analysis set to more precisely define their performance peer group  1099 . 
         [0045]    The dynamic nature of this method allows users to identify key factors influencing performance. The procedure can be applied to general unit types or tailored to a specific generating unit. The result is a more focused peer unit group against which comparisons can be made. Referring to Example 1, an analysis of data according to a preferred embodiment of the method is disclosed. 
         [0046]    The foregoing disclosure and description of various embodiments of the invention are illustrative and explanatory thereof, and various changes in the details of the illustrated system and method may be made without departing from the scope of the invention.