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ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis...

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ETAP PowerStation 4.0 User Guide Copyright 2001 Operation Technology, Inc. All Rights Reserved This manual has copyrights by Operation Technology, Inc. All rights reserved. Under the copyright laws, this manual may not be copied, in whole or in part, without the written consent of Operation Technology, Inc. The Licensee may copy portions of this documentation only for the exclusive use of Licensee. Any reproduction shall include the copyright notice. This exception does not allow copies to be made for other persons or entities, whether or not sold. Under this law, copying includes translating into another language. Certain names and/or logos used in this document may constitute trademarks, service marks, or trade names of Operation Technology, Inc. or other entities. Access, Excel, ODBC, SQL Server, Windows NT, Windows 2000, Windows Me, Windows 98, Windows XP, and Microsoft Word are registered trademarks of Microsoft Corporation. AutoCad is a registered trademark of Autodesk. Oracle is a registered trademark of Oracle Corporation. PowerPlot is a registered trademark of Jackson & Associates. Crystal Reports is a registered trademark of Seagate Software. MATLAB and Simulink are registered trademarks of MathWorks Screen shot(s) reprinted by permission from Microsoft Corporation. Operation Technology, Inc. believes that the information contained herein is accurate as of its publication date, and such information is subject to change without notice. This information is provided “as is” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability, fitness for a particular purpose, or non- infringement. Operation Technology, Inc. assumes no responsibility for errors or omissions in this publication or any other documents referenced in this publication. Operation Technology, Inc. Southern California (949) 462-0100 Sales (949) 462-0400 Fax (949) 462-0400 User Support
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Page 1: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

ETAP PowerStation 4.0

User Guide

Copyright 2001 Operation Technology, Inc.

All Rights Reserved This manual has copyrights by Operation Technology, Inc. All rights reserved. Under the copyright laws, this manual may not be copied, in whole or in part, without the written consent of Operation Technology, Inc. The Licensee may copy portions of this documentation only for the exclusive use of Licensee. Any reproduction shall include the copyright notice. This exception does not allow copies to be made for other persons or entities, whether or not sold. Under this law, copying includes translating into another language. Certain names and/or logos used in this document may constitute trademarks, service marks, or trade names of Operation Technology, Inc. or other entities. • Access, Excel, ODBC, SQL Server, Windows NT, Windows 2000, Windows Me, Windows

98, Windows XP, and Microsoft Word are registered trademarks of Microsoft Corporation. • AutoCad is a registered trademark of Autodesk. • Oracle is a registered trademark of Oracle Corporation. • PowerPlot is a registered trademark of Jackson & Associates. • Crystal Reports is a registered trademark of Seagate Software. • MATLAB and Simulink are registered trademarks of MathWorks • Screen shot(s) reprinted by permission from Microsoft Corporation. Operation Technology, Inc. believes that the information contained herein is accurate as of its publication date, and such information is subject to change without notice. This information is provided “as is” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability, fitness for a particular purpose, or non-infringement. Operation Technology, Inc. assumes no responsibility for errors or omissions in this publication or any other documents referenced in this publication.

Operation Technology, Inc. Southern California

(949) 462-0100 Sales (949) 462-0400 Fax (949) 462-0400 User Support

Page 2: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Chapter 23

Reliability Assessment Analysis

Distribution system reliability assessment is concerned with the availability and quality of power supply at each customer’s service entrance. Analysis of customer failure statistics shows that failures in distribution systems contribute as much as 90% towards the unavailability of supply to a load as compared with other parts of electric power systems. These statistics reinforce the need for reliability evaluation of distribution systems. The basic reliability indices normally used to predict or assess the reliability of a distribution system are the three reliability indices: • Load point average failure rate λ, • Average outage duration r, • Annual unavailability U In order to incorporate the severity or significance of a system outage, two expanded sets of indices can be calculated, by using these three basic indices, the number, and average load of customers connected at each load point in the system, and the customer interruption cost. One set is the system reliability indices: • System Average Interruption Frequency Index (SAIFI), • System Average Interruption Duration Index (SAIDI), • Customer Average Interruption Duration Index (CAIDI), • Average Service Availability Index (ASAI), • Average Service Unavailability Index (ASUI) These additional indices can be used to assess the overall behavior of the distribution system. The other set is the reliability cost/worth indices: • Expected Energy Not Supply (EENS), • Expected Interruption Cost (ECOST), • Interrupted Energy Assessment Rate (IEAR)

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Reliability Assessment Analysis Toolbar

The indices EENS, ECOST, and IEAR can be those at each load points or for the overall system. All these indices can be used to evaluate the reliability of an existing distribution system and to provide useful planning information regarding improvements to existing systems and the design of new distribution systems. Moreover, in order to analyze the sensitivity of a reliability index EENS or ECOST with respect to failure rate of different elements, element contributions to that index and their rankings can be used. The rankings can be for a load point or the overall system. Using ETAP PowerStation Reliability Analysis program, all the indices and rankings given above can be evaluated. The program provides you with the best tool to efficiently model various power system elements and devices to include their effects on the distribution system reliability, such as fault isolation and load restoration through the operation of switching devices. This program is quite suitable for reliability analysis of large-scale systems of general configurations. By using this program, the distribution system reliability can be assessed, and the merits of various reinforcement schemes available to the planner can be quantitatively evaluated to ensure that limited capital resources are used to achieve the greatest possible improvement in the system reliability. Some of the main features of the ETAP PowerStation Distribution System Reliability Analysis Study are summarized below: • Common & Integrated Database • Fully Inherited 3-D Data Structure, Including Infinite Presentations, Unlimited Configurations, &

Multiple Data Revisions • Looped, Radial, or Combined Systems • Systems with Multiple Source Buses (Generators/Utilities) • Systems with Isolated Sub-Systems • Systems with De-Energized Buses & Branches • Fault Isolation and Load Restoration • Modeling of Single-Pole Double-Throw Switches • Modeling of Normally Closed/Open Tie Circuit Connections • User-Expandable Sector Interruption Cost Library • Three Basic Reliability Indices (λ, r, U) for each load point • Overall System Reliability Indices (SAIFI, SAIDI, CAIDI, ASAI, ASUI) • Reliability Cost/Worth Indices EENS, ECOST and IEAR for each load point • Reliability Cost/Worth Indices EENS, ECOST and IEAR for the Overall System • Element Contributions to the Load Point EENS and ECOST and Their Rankings • Element Contributions to the Overall System EENS and ECOST and Their Rankings • Graphic One-Line Display of Study Results • Graphic Plots of Element Contributions and Their Rankings for the Load Point EENS and ECOST for

Viewing & Printing • Graphic Plots of Element Contributions and Their Rankings for the Overall System EENS and

ECOST for Viewing & Printing • Tabulated Input Data, Load Point Reliability Indices, Overall System Reliability Indices, Element

Contributions and their rankings

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Reliability Assessment Analysis System Analysis Toolbar

Reliability System Analysis Toolbar The Distribution System Reliability Analysis Toolbar will appear on the screen when you are in the Distribution System Reliability Analysis Study mode. This toolbar has six function keys as shown below.

Run Distribution System Reliability Analysis Distribution System Reliability Analysis Display Options View Distribution System Reliability Output File Distribution System Reliability Analysis Plots Halt Current Calculation Get Online Data Get Archived Data

Run Distribution System Reliability Analysis Select a study case from the Study Case Toolbar when you are in Distribution System Reliability Analysis Study mode. Click on the Run Distribution System Reliability Analysis button to perform a Distribution System Reliability Analysis study. A dialog box will appear for you to specify the output report name if the output file name is set to the Prompt in the Output Report list box. The Distribution System Reliability Analysis study results will appear on the one-line diagram and can be viewed in output report tabulated formats and plot formats.

Distribution System Reliability Analysis Display Options Click on the Distribution System Reliability Analysis Display Options button to customize the one-line diagram annotation display options under the Distribution System Reliability Analysis Study mode, and to specify the load point reliability indices to be displayed. See Display Options for more information.

View Output File Click on this button to open up the Distribution System Reliability Analysis Report Manager dialog box from which you can select a variety of pre-formatted output files. Select a file type and click on the OK button to bring up the output file. A detailed explanation of the Distribution System Reliability Analysis Report Manager is given in section 27.6.

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Reliability Assessment Analysis System Analysis Toolbar

You can also select output files from the Output Report list box.

This list contains all the output files in the current project folder.

Distribution Reliability Analysis Plots To view plots of EENS/ECOST rankings, click on this icon to bring up a dialog box to select load points/buses/system from a list.

Halt Current Calculation The Stop Sign button is normally disabled. When a distribution system reliability analysis has been initiated, this button becomes enabled and shows a red stop sign. Clicking on this button will terminate the current calculation. One-line diagram displays will not be available if you terminate the calculation before it completes, and the output report will be incomplete.

Get On-Line Data This button is reserved for the on-line application, PSMS.

Get Archived Data T his button is reserved for the on-line application, PSMS.

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Reliability Assessment Analysis Study Case Editor

23.1 Study Case Editor The Distribution System Reliability Analysis Study Case Editor contains solution control variables, report options, and component/system plot display selection. PowerStation allows you to create and save an unlimited number of study cases for each type of study. Like any other study types, you can easily switch between different distribution system reliability analysis study cases. This feature is designed to organize your study efforts and save you time. A study case can be used for any combination of any configuration status, one-line diagram presentation, and Base/Revision Data. To create a new distribution system reliability analysis study case, go to the Project View, right-click on the Distribution System Reliability Analysis sub-folder inside the Study Case folder, and select Create New. The program will then create a new study case, which is a copy of the default study case, and it can be added to the Distribution System Reliability Analysis sub-folder.

When you are in the Distribution System Reliability Analysis mode, you can access the Distribution System Reliability Analysis Study Case Editor by clicking on the Study Case button on the Study Case Toolbar. You can also access this editor from the Project View by clicking on the Distribution System Reliability Analysis sub-folder under the Study Cases folder. The Distribution System Reliability Analysis Study Case Editor consists of three pages: Info page, Sensitivity Analysis Report page and the Plot page.

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Reliability Assessment Analysis Study Case Editor

23.1.1 Info Page This page is provided for you to specify some general solution parameters and study case information.

Study Case ID The study case ID is shown in this entry field. You can rename a study case by simply deleting the old ID and entering a new ID. Study case ID can be up to 25 alphanumeric characters. Use the Navigator button at the bottom of the editor to go from one study case to another.

Loading In this section, you can specify the system loading conditions for the Distribution System Reliability Analysis.

Category Select one of the 10 loading categories for this study case. With the selection of any category, PowerStation uses the percent loading of individual motors and static loads as specified for the selected category. Note that you can assign loading to each one of the 10 categories in the Nameplate page, Loading page, or Rating page for induction machines, synchronous motors, static loads, lumped loads, MOVs, capacitors, UPSs, inverters, and chargers, respectively.

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Reliability Assessment Analysis Study Case Editor

None Select Normal to use the percent loading of each load as entered for the selected loading category, i.e., no diversity factor is considered.

Bus Maximum When the Maximum bus loading option is selected, the loading of all motors and static loads will be multiplied by the maximum diversity factor of the bus that they are directly connected to. Using this option, you can define the different loading for reliability analysis studies with each bus having a different maximum diversity factor. This study option is helpful when the future loading of the electrical system has to be considered.

Bus Minimum When the Minimum bus loading option is selected, the loading of all motors and static loads will be multiplied by the bus minimum diversity factor of the bus that they are directly connected to. Using this option, you can define the different loading for reliability analysis studies with each bus having a different minimum diversity factor. This study option may be useful in some cases where the effect of light loading condition needs to be investigated.

Global When this option is selected, PowerStation will ask you to enter global diversity factors for motors and static loads, respectively. When you select this option, PowerStation will globally multiply all motors and static loads of the selected loading category with the entered values. When using this option you, can define the different loading for reliability analysis studies with fixed diversity factors for all loads. Note that a motor load-multiplying factor of 125% implies that the motor loads of all buses are increased by 25% above their values as specified by the selected loading category. This value can be smaller or greater than 100% .

Operating Load Check this option to use operating P and Q as specified in the relevant component editors. Note that if this option is selected, it is required that a load flow calculation is run first in order to obtain the operating load.

Charger Loading

Load Category Select this option to use the P and Q specified in the Loading Category section of Charger Editor for chargers.

Operating Load Select this option to use the P and Q as specified in the Operating Load section of the Charger Editor. Note that if this option is selected, it is required that a DC load flow calculation is run first in order to estimate the charger load.

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Reliability Assessment Analysis Study Case Editor

Remarks 2nd Line You can enter up to 120 alphanumeric characters in this remark box. Information entered here will be printed on the second line of every output report page header. These remarks can provide specific information regarding each study case. Note that the first line of the header information is global for all study cases and entered in the Project Information Editor.

23.1.2 System Index Report Page In this page, you can specify the numbers of elements that contribute most to system reliability indices EENS and ECOST and their rankings will be reported.

System Contribution Ranking for Reporting

No of Most Contributing Elements to EENS Select the number of the elements that contribute most to the index EENS.

No of Most Contributing Elements to ECOST

Operation Technology, Inc. 23-8

Select the number of the elements that contribute most to the index ECOST.

ETAP PowerStation 4.0

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Reliability Assessment Analysis Study Case Editor

23.1.3 Load Index Report Page In this page, you can specify the numbers of elements that contribute most to load point reliability indices EENS and ECOST and their rankings will be reported.

Element Contribution Ranking for Reporting

No of Most Contributing Elements to EENS Select the number of the elements that contribute most to the index EENS.

No of Most Contributing Elements to ECOST Select the number of the elements that contribute most to the index ECOST.

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Reliability Assessment Analysis Study Case Editor

23.1.4 Plot Page Select the elements you want to display in plot format.

System Index

Plot/Tabulate System Reliability Indices Check this box to plot/tabulate system reliability indices.

Element Index In this section, you can specify the load points that will be plotted.

Element Type Select types of components or devices from the list. Only the components associated with the listed types can be selected for plotting/tabulating.

Plot Options

Device ID This table provides a list of the devices or components for the given Device Type. You can select a device or component and click next to it under the Plot/Tabulate column.

Plot/Tabulate You also can include a device or component in the plot list by first selecting that device or component, and then checking this box. An X will be placed next to this device or component in the Plot/Tabulate column.

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Reliability Assessment Analysis Display Options

23.2 Display Options The Distribution System Reliability Analysis Display Options consist of a Results page, and three pages for AC, AC-DC, and DC info annotations. Note that the colors and displayed annotations selected for each study case are specific to that study

23.2.1 Results Page Select the information annotations to be displayed on the one-line diagram.

Color Select the color for the reliability analysis result annotations to be displayed on the one-line diagram.

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Reliability Assessment Analysis Display Options

Load Point Reliability Indices

Average Failure Rate λ Check this box to display the average failure rate for the Buses/Generators/Load Points checked from Display Results below.

Average Outage Duration r Check this box to display the average outage duration for the Buses/Generators/Load Points checked from Display Results below.

Annual Outage U Check this box to display the annual unavailability for the Buses/Generators/Load Points checked from Display Results below.

Expected Energy Not Supplied EENS Check this box to display the EENS for the Buses/Generators/Load Points checked from Display Results below. Note that the EENS for a bus is defined as the EENS of the loads that are directly connected to the bus owing to the interruption of this bus.

Expected Interruption Cost ECOST Check this box to display the ECOST for the Buses/Generators/Load Points checked from Display Results below. Note that the EENS for a bus is defined as the ECOST of the loads that are directly connected to the bus owing to the interruption of this bus.

Interruption Energy Assessment Rate IEAR Check this box to display the IEAR for the Buses/Generators/Load Points checked from Display Results below.

Display Results

Buses Check this box to display the reliability indices checked from the section of Load Point Reliability Indices for buses.

Generators Check this box to display the reliability indices checked from the section of Load Point Reliability Indices for generators.

Load Points Check this box to display the reliability indices checked from the section of Load Point Reliability Indices for load points.

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Reliability Assessment Analysis Display Options

23.2.2 AC Info Page

Color Select the color for information annotations to be displayed on the one-line diagram.

ID Select the check boxes under this heading to display the ID’s of the selected AC elements on the one-line diagram.

Rating Select the check boxes under this heading to display the ratings of the selected AC elements on the one-line diagram.

Device Type Rating Gen. (Generator) kW / MW Power Grid (Utility) MVAsc Motor HP / kW Load kVA / MVA Panel Connection Type (# of Phases - # of Wires) Transformer kVA / MVA Branch, Impedance Base MVA Branch, Reactor Continuous Amps Cable / Line # of Cables - # of Conductor / Cable - Size Bus kA Bracing Node Bus Bracing (kA) CB Rated Interrupting (kA) Fuse Interrupting (ka) Relay 50/51 for Overcurrent Relays PT & CT Transformer Rated Turn Ratio

kV Select the check boxes under this heading to display the rated or nominal voltages of the selected elements on the one-line diagram. For cables/lines, the kV check box is replaced by the button. Click on this button to display the cable/line conductor type on the one-line diagram.

A Select the check boxes under this heading to display the ampere ratings of the selected elements on the one-line diagram. For cables/lines, the Amp check box is replaced by the button. Click on this button to display the cable/line length on the one-line diagram.

Z Select the check boxes under this heading to display the impedance values of the selected elements on the one-line diagram.

D-Y

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Reliability Assessment Analysis Display Options Select the check boxes under this heading to display the connection types of the selected elements on the one-line diagram.

Composite Motor Click on this check box to display the composite motor ID’s on the one-line diagram, then select the color in which the ID’s will be displayed.

Use Default Options Click on this check box to use PowerStation’s default display options.

23.2.3 AC-DC Info Page

Color Select the color for information annotations to be displayed on the one-line diagram.

ID Select the check boxes under this heading to display the ID’s of the selected AC-DC elements on the one-line diagram.

Rating Select the check boxes under this heading to display the ratings of the selected AC-DC elements on the one-line diagram.

Device Type Charger Inverter UPS VFD

kV Click on the check boxes under this heading to display the rated or nominal voltages of the selected elements on the one-line diagram.

A Click on the check boxes under this heading to display the ampere ratings of the selected elements on the one-line diagram.

Composite Network Click on this check box to display the composite network ID’s on the one-line diagram, then select the color in which the ID’s will be displayed.

Use Default Options Click on this check box to use PowerStation’s default display options.

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Reliability Assessment Analysis Display Options

23.2.4 DC Info Page

Color Select the color for information annotations to be displayed on the one-line diagram.

ID Select check boxes under this heading to display the ID’s of selected DC elements on the one-line diagram.

Rating Select the check boxes under this heading to display the ratings of the selected DC elements on the one-line diagram.

Device Type Battery Motor Load Elementary Diagram Converter Branch Cable Bus Node CB Fuse Switch Composite Motor

kV Select the check boxes under this heading to display the rated or nominal voltages of the selected elements on the one-line diagram. For cables/lines, the kV check box is replaced by the button. Click on this button to display the cable/line conductor type on the one-line diagram.

A Select the check boxes under this heading to display the ampere ratings of the selected elements on the one-line diagram. For cables/lines, the Amp check box is replaced by the button. Click on this button to display the cable/line length on the one-line diagram.

Z Select the check boxes under this heading to display the impedance values of the selected elements on the one-line diagram.

Composite Motor Click on this check box to display the composite motor ID’s on the one-line diagram, then select the color in which the ID’s will be displayed.

Use Default Options Click on this check box to use PowerStation’s default display options.

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Reliability Assessment Analysis Modeling and Calculation Method

23.3 Modeling and Calculation Method Electric distribution system reliability analysis involves modeling different components of distribution systems, computing reliability indices at load points and for the overall AC system, and ranking the elements that contribute to the load point/bus/system indices EENS and ECOST. This section briefly discusses some fundamentals and underlying principles on the PowerStation Distribution System Reliability Analysis program, with the focus on applications with PowerStation

23.3.1 AC Component and System Modeling • A two-state up/down representation is used for the operation/repair cycle of an element (such as lines,

cables, transformers, breaks, fuses, switches, loads and busbars). • Normally open tie circuit connections can be taken into account. Currently, a normally open tie

circuit connection is defined in the ETAP as the connection that satisfies: (i) the two buses that it is connected are energized (ii) it is composed of only the components of PD’s, (iii) the connection is in service and (iv) it contains at least one normally open PD.

• As a default option of a sector interruption cost library, a Standard Industrial Classification (SIC) is used to divide customers into seven categories of large user, industrial, commercial, agriculture, residential, government & institutions and office & buildings. Users can change this library.

• The sector interruption cost library gives the Sector Customer Damage Functions (SCDF), i.e., the interruption costs for several discrete outage durations. A log-log interpolation of the cost data is used where the interruption duration lies between two separate times. In the case of durations greater than the largest duration, a linear extrapolation with the same slope as that between the second largest and largest durations will be used to calculate the interruption cost.

• Any switching device, such as breaker, fuse, contactor, and switch, has the function of fault isolation. Only an overcurrent protective device (such as breaker and fuse) can interrupt fault currents.

• A fault in a radial sub-system is interrupted by the nearest overcurrent PD on its source side; a fault in a meshed sub-system is interrupted by its surrounding nearest overcurrent PD’s. The associated set of interrupted load points (LP’s) is called the “interrupted LP zone” of the faulted element.

• A fault in a radial sub-system is isolated by the nearest switching device of any kind on its source side; a fault in a meshed sub-system is isolated by its surrounding nearest switching devices. The associated set of isolated load points is called the “isolated LP zone” of the faulted element.

• The affected load points in the isolated LP zone of an element will be connected after the repair of the faulty component, while the ones contained in its interrupted LP zone but outside its isolated LP zone will have the supply restored after a short switching or sectionalizing time.

• The switching time for a load is internally set to the switching time of the component that is the nearest to this load. The component may be an equivalent cable, switching device, or bus.

• The EENS and ECOST for a bus are respectively defined as the Expected Energy Not Supply and Expected Interruption Cost of the loads that are directly connected to that bus due to the outage of that bus.

23.3.2 AC-DC Converter Models In the current version of ETAP PowerStation, the distribution system reliability analysis involves only AC systems. The AC-DC converters are modeled below.

Charger & UPS In the current version of ETAP PowerStation, when performing AC reliability analyses, chargers and UPSs are considered as loads connected to their input AC buses.

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Reliability Assessment Analysis Modeling and Calculation Method

Inverter An inverter is treated as a power supply source like a generator or utility.

Variable Frequency Drive (VFD) A VFD can only be inserted between a motor or a lump load and its terminal bus, and is treated as a branch between the terminal bus and the motor.

23.3.3 Modeling Assumptions/Limitations The current distribution system reliability analysis makes the following assumptions: • Only AC systems are considered. • All switching devices operate successfully when required. • Switching devices can be opened whenever possible to isolate a fault. Power supply can be restored

to provide power to as many load points as possible using appropriate switching actions and available alternative supplies.

• All failures are statistically independent. Multi-order faults are ignored.

23.3.4 Distribution System Reliability Indices The distribution system reliability is usually measured in terms of several indices that are defined below.

Average Failure Rate at Load Point I, λi(f/yr)

∑∈

=Nej

jei ,λλ

Where λe,j is the average failure rate of element j; Ne is the total number of the elements whose faults will interrupt load point i.

Annual Outage Duration at Load Point i, Ui(hr/yr)

∑∈

=Nej

ijjei rU ,λ

where rij is the failure duration at load point i due to a failed element j.

Average Outage Duration at Load Point i, ri(hr)

iii Ur λ/=

Expected Energy Not Supplied Index at Load Point i, EENSi(MWhr/yr) EENSi = ii UP where Pi is the average load of load point i.

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Reliability Assessment Analysis Modeling and Calculation Method

Expected Interruption Cost Index at Load Point i, ECOSTi(k$/yr)

∑∈

=Nej

jeijii rfPECOST ,)( λ

where f(rij) is the SCDF.

Interrupted Energy Assessment Rate Index at Load Point i, IEARi($/kWhr)

i

ii EENS

ECOSTIEAR =

System Average Interruption Frequency Index, SAIFI(f/customer.yr)

∑∑==

i

ii

NN

SAIFIλ

servedcustomer ofnumber Total onsinterrupticustomer ofnumber Total

where N i is the number of customers at load point i; the symbol Σ means the summation for all load points.

System Average Interruption Duration Index, SAIDI(hr/customer.yr)

∑∑==

i

ii

NNU

SAIDIservedcustomer ofnumber Totaldurationson interrupticustomer of Sum

Customer Average Interruption Duration Index, CAIDI(hr/customer interruption)

ii

ii

NNU

CAIDI∑∑==

λonsinterrupticustomerofnumberTotalsdurationoninterrupticustomerofSum

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Reliability Assessment Analysis Modeling and Calculation Method

Average Service Availability Index, ASAI(pu)

∑∑ ∑

×−×

=

=

87608760

demandedhoursCustomerservice availableofhoursCustomer

i

iii

NUNN

ASAI

Where 8760 is the number of hours in a calendar year.

Average Service Unavailability Index, ASUI(pu)

ASAIASUI −= 1

System Expected Energy Not Supplied Index, EENS(MWhr/yr)

EENS = Total energy not supplied by the system = ∑ iEENS

System Expected Interruption Cost Index, ECOST(k$/yr)

∑= iECOSTECOST

Average Energy Not Supplied Index, AENS(MWhr/customer.yr)

∑==i

i

NEENS

AENSservedcustomer ofnumber Total

system by the suppliednot energy Total

System Interrupted Energy Assessment Rate Index, IEAR($/kWhr)

EENS

ECOSTIEAR =

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Page 21: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Reliability Assessment Analysis Modeling and Calculation Method

23.3.5 Distribution System Reliability Analysis Study The Distribution System Reliability Analysis employs a new analytical algorithm to assess the reliability indices of mixed radial and meshed distribution systems. This algorithm basically uses the algorithm for radial distribution systems since the meshed network, if any, is first converted to a radial network. Therefore, the employed algorithm is quite efficient and suitable for large-scale distribution systems of general configurations. The distribution system reliability analysis study generates crystal output reports showing the system input data, reliability indices results, element ranking information, and tabulation of the results. Some of these results can also be viewed directly from the one-line diagram using the Distribution System Reliability Display Options Editor.

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Reliability Assessment Analysis Required Data

23.4 Required Data To run a distribution system reliability analysis study, you only need to provide some reliability-related data, such as failure rates, repair times, and switching times of network elements. A summary of these data for different types of elements is given in this section. Note that Maintenance Outage Rate and Maintenance Outage Time below are not used in reliability calculation for this version.

Bus Data • Active Failure Rate • Repair Time • Switching Time • Replacement Time

Branch Data

2-Winding & 3-Winding Transformers • Active Failure Rate • Passive Failure Rate • Repair Time • Switching Time • Replacement Time

Cable/Transmission Line • Length • Active Failure Rate • Passive Failure Rate • Repair Time • Switching Time • Replacement Time

Impedance & Current-Limiting Reactor • Active Failure Rate • Passive Failure Rate • Repair Time • Switching Time • Replacement Time

Power Grid (Utility) & Synchronous Generator Data • Active Failure Rate • Repair Time • Switching Time • Replacement Time

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Page 23: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Reliability Assessment Analysis Required Data

Synchronous Motor Data • Active Failure Rate • Repair Time • Replacement Time • Load Sector • Quantity (No. of Loads)

Induction Machine Data • Active Failure Rate • Repair Time • Replacement Time • Load Sector • Quantity (No. of Loads)

Static Load Data • Active Failure Rate • Repair Time • Replacement Time • Load Sector • Quantity (No. of Loads)

Lumped Load Data • Active Failure Rate • Repair Time • Replacement Time • Load Sector • Quantity (No. of Loads)

UPS Data • Active Failure Rate • Passive Failure Rate • Repair Time • Switching Time • Replacement Time • Load Sector

VFD Data • Active Failure Rate • Passive Failure Rate • Repair Time • Switching Time • Replacement Time

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Page 24: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Reliability Assessment Analysis Required Data

Charger Data • Active Failure Rate • Repair Time • Switching Time • Replacement Time • Load Sector

Inverter Data • Active Failure Rate • Repair Time • Switching Time • Replacement Time

Study Case Parameters • Study Case ID • Report Option (for Plots and Crystal Reports)

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Page 25: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Reliability Assessment Analysis Output Report

23.5 Output Report Output reports for distribution system reliability analysis studies are available in different levels and are arranged into two formats: crystal output report, one-line diagram display.

23.5.1 Distribution System Reliability Analysis Report Manager Click on the View Output File button on the Distribution System Reliability Analysis Toolbar to open the Distribution System Reliability Analysis Report Manager. The Distribution System Reliability Analysis Report Manager provides different formats for Crystal Reports and consists of four pages.

Complete Page From this page you can select the report format that gives you the complete output report.

Input Page This page provides the formats for different input data.

Result Page This page provides the formats for different calculation results.

Summary Page This page provides the summary from calculation results.

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Page 26: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Reliability Assessment Analysis Output Report

23.5.2 Distribution System Reliability Crystal Report If the last study you have run is the distribution system reliability analysis, then by clicking on the Report Manager button on the Study Case Toolbar or by selecting the Crystal Report format from the Reliability Analysis Toolbar, you will be able to open and view the crystal output report for the distribution system reliability analysis study. The distribution system reliability analysis study crystal report contains the following major sections:

Cover Page This is the first page of the distribution system reliability analysis study crystal report. It includes the information from a number of different types of buses, branches, unit system, project file name, and the output file name and its location.

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Page 27: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Reliability Assessment Analysis Output Report

Bus Input Data This section reports the input data related to system buses, including their ID, nominal kV, failure rate, repair time, switching time and replacement time.

Load Input Data This section reports the input data related to system loads that include synchronous motor, induction machine, static Load, lumped load, UPS, charger, capacitor, and filter. The input data reported are load ID and type, connected bus ID, average load, user sector ID, # of loads, failure rate, repair time and replacement time.

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Reliability Assessment Analysis Output Report

Source Input Data This section reports the input data related to system sources that include power grid (utility) and synchronous generator. The input data reported are source connected bus ID, source ID and type, failure rate, repair time, switching time and replacement time.

Branch Input Data This section reports the input data related to system branches that include cables, transmission lines, impedances, reactors, and 2-winding and 3-winding transformers. The input data reported are branch ID, branch type, length (if any), total failure rate, active failure rate, repair time, switching time, and replacement time.

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Reliability Assessment Analysis Output Report

Branch Connection This section reports branch connection information for all branches in the system. It shows the branch ID, branch type, from which bus and to which bus it is connected.

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Reliability Assessment Analysis Output Report

Sector Interruption Cost Library Data This section lists the library data of sector interruption cost.

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Reliability Assessment Analysis Output Report

Switching Device Input Data This section reports the input data related to protective devices. The input data reported are switching device ID, switching device type, active failure rate, passive failure rate, repair time, switching time and replacement time.

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Page 32: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Reliability Assessment Analysis Output Report

Load Point Report In the Load Point Report section, the load point ID, user sector, load point connected bus ID (if any), average (active) failure rate, average outage duration, annual outage duration, EENS, ECOST and IEAR are reported. Note that only the buses that are selected for plotting in the Reliability Analysis Study Case Editor are tabulated.

EENS Sensitivity Analysis In the EENS Sensitivity Analysis section, the system/bus/load point ID and type, corresponding contributing element ID, type and EENS are reported.

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Page 33: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Reliability Assessment Analysis Output Report

ECOST Sensitivity Analysis In the ECOST Sensitivity Analysis section, the system/bus/load point ID and type, corresponding contributing element ID, type and ECOST are reported.

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Reliability Assessment Analysis Output Report

Summary The Summary section includes the information from a number of different types of buses, branches, system frequency, unit system, project file name, output file name, and its location.

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Reliability Assessment Analysis Output Report

23.5.3 Distribution System Reliability Analysis Display By using the Distribution System Reliability Analysis Display Options Editor, you can choose different results to be displayed on the one-line diagram for the distribution system reliability analysis study. The following screen capture shows a one-line diagram display.

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Page 36: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Reliability Assessment Analysis Plots

23.6 Plots Plots are available for EENS ranking and ECOST ranking of system/load points. To select a plot, click on the Reliability Analysis Plots button located on the Reliability Analysis Toolbar.

Device Type Select a device type.

Device ID Select the devices that you want to plot. This box lists all the devices that are selected in the Reliability Study Case editor, Plot page, for the selected device type. Multiple devices can be selected.

Plot Type For Reliability Analysis plot, the following curves are available.

EENS Plot EENS ranking for the selected devices.

ECOST Plot ECOST ranking for the selected devices.

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Page 37: ETAP PowerStation 4 - ISI Academy PDF/Chapter 23... · Chapter 23 Reliability Assessment Analysis Distribution system reliability assessment is concerned with the availability and

Reliability Assessment Analysis Plots

A set of sample plots is shown below.

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