Network Analysis for Otter Network Analysis for Otter Tail PowerTail Power

Presented by Les Jarriel Presented by Les Jarriel (l.f.jarriel@ieee.org)(l.f.jarriel@ieee.org)

Power Software & Consulting Inc. Power Software & Consulting Inc.

Support by Bob Endahl (OTP)Support by Bob Endahl (OTP)

Dr. Shouming Zhang, Ken Audet, Sam Dr. Shouming Zhang, Ken Audet, Sam Phillipson (Siemens PTI)Phillipson (Siemens PTI)

OTP OverviewOTP Overview

~127,000 customers~127,000 customers

5000+ miles of 5000+ miles of transmissiontransmission

~650 MW generating ~650 MW generating capacitycapacity

Operational ModelOperational Model2700+ buses2700+ buses

1800+ substations1800+ substations

5000+ switches5000+ switches

6800+ real-time 6800+ real-time measurementsmeasurements

• PNAA (Power Network Analysis PNAA (Power Network Analysis Application)Application)

• Initially planned as add-on to the Initially planned as add-on to the existing EMSexisting EMS

• Project ConcernsProject Concerns– Low voltage (41-115 kV) network regions Low voltage (41-115 kV) network regions

with limited telemetrywith limited telemetry– Costs had increased since original quotationCosts had increased since original quotation

Project OverviewProject Overview

Technical ChallengesTechnical Challenges

1.1. Pockets of unobservable Pockets of unobservable radial and loop networksradial and loop networks

2.2. Includes unmetered cap banks Includes unmetered cap banks controlled by voltagecontrolled by voltage

3.3. Use distribution factors based Use distribution factors based on energy meterson energy meters

4.4. Connects to high voltage network Connects to high voltage network with potential meter errorswith potential meter errors

An Alternate ApproachAn Alternate Approach

Standalone PNAA Provides:Standalone PNAA Provides:• PSS/E model import (starting point)PSS/E model import (starting point)• Fully-integrated one-line displaysFully-integrated one-line displays

• Single-substation, Map Board and Single-substation, Map Board and Geographic OverviewGeographic Overview

• Graphical model editing capabilityGraphical model editing capability• User-configurable tabular displaysUser-configurable tabular displays• Support for Python scriptingSupport for Python scripting• Close interaction between Vendor and Close interaction between Vendor and

CustomerCustomer

A Unique System A Unique System ArchitectureArchitecture

PNAA PNAA System ConfigurationSystem Configuration

Standalone System Standalone System ImplicationsImplications

• Separate displays (PNAA vs. SCADA)Separate displays (PNAA vs. SCADA)• Separate databaseSeparate database• ICCP mappings requiredICCP mappings required

– Many going to ISO or RC anywayMany going to ISO or RC anyway• Separate infrastructure (no delays)Separate infrastructure (no delays)• Costs – more options with standaloneCosts – more options with standalone• Vendor supportVendor support

Project StepsProject Steps• Start with a comprehensive PSS/E modelStart with a comprehensive PSS/E model• Reduce the model sizeReduce the model size

– Use 3Use 3rdrd party tool to equivalence party tool to equivalence• Import the reduced model into PNAAImport the reduced model into PNAA• Independently validate the conversionIndependently validate the conversion

– Export to PSS/E and compare PF resultsExport to PSS/E and compare PF results• Simultaneously build one-line displays while Simultaneously build one-line displays while

adding breaker detail to the modeladding breaker detail to the model• Import ICCP measurement mappings and ‘plug Import ICCP measurement mappings and ‘plug

in’ the OPC/ICCP adaptersin’ the OPC/ICCP adapters• SE Tuning: start small and build outSE Tuning: start small and build out

PNAA – FeaturesPNAA – FeaturesNetwork Analysis Functions

Topology Analysis Power Flow State Estimator Contingency Analysis

(fully supports complex user-defined contingencies and protection schemes)

User Interface Single-substation, geographic overview and full

‘map board’ one-line diagram displays Custom symbol support with built-in editor Simultaneous measurements-and-results display Color-coded and animated flow arrows Color contouring by flow or voltage violation Configurable spreadsheet views 1-click toggle between real-time and study modes

Geographic DisplaysGeographic Displays

Map Board DisplaysMap Board Displays

Color ContouringColor Contouring

2-Way Navigation2-Way Navigation

State EstimatorState Estimator

• Performance (< 2s for OTP model)

• Accurately estimates sub-transmission (low voltage) areas with limited telemetry

• Supports flow measurements on breakers/switches

• Supports ‘hybrid’ operations/planning model

• Supports telemetered flow limits

• Supports direction-dependent flow limits

• Bad measurement identification

• Automatic switch status correction

• Powerful diagnostic/tuning interface

• Configurable results publication to ICCP

Highlights

SE Tuning – Topology Error SE Tuning – Topology Error DetectionDetection

SCADA: 10 MW → SE: ← 13 MW

SCADA: ← 10 MWSE: ← 33 MW

Overcoming the Primary Overcoming the Primary Technical ChallengeTechnical Challenge

Unobservable IslandsUnobservable Islands• Conventional Approach: Pseudo-Conventional Approach: Pseudo-

Measurement TechnologyMeasurement Technology• New Approach: Virtual Real-Time New Approach: Virtual Real-Time

Measurements TechnologyMeasurements Technology• Automatically identify unobservable islands and Automatically identify unobservable islands and

corresponding feeder measurementscorresponding feeder measurements• Apply a Apply a new algorithm to sum loads and losses which takes new algorithm to sum loads and losses which takes

into account larger impedance and MW lossinto account larger impedance and MW loss• Take into account the effects of shunts in unobservable Take into account the effects of shunts in unobservable

islandsislands

Virtual Real-Time Measurements Virtual Real-Time Measurements TechnologyTechnology

Graphical Model EditingGraphical Model Editing

• Add equipmentAdd equipment– Intuitive connectivityIntuitive connectivity– 1-click breaker insert1-click breaker insert– Copy/Paste equipmentCopy/Paste equipment

• Reconnect equipmentReconnect equipment• Delete equipmentDelete equipment• Edit equipment attributesEdit equipment attributes• Synchronize with model changesSynchronize with model changes

Custom Tabular Custom Tabular DisplaysDisplays

• Start with standard default displayStart with standard default display• Filter by area, substation, voltage level, Filter by area, substation, voltage level,

device type, etc.device type, etc.• Hide unwanted columnsHide unwanted columns• Edit visible column widthsEdit visible column widths• Save view configurationSave view configuration

• Unlimited number of custom “views”Unlimited number of custom “views”

• Each saved view is a sub-tabEach saved view is a sub-tab• 1-click activation1-click activation• Sort by any columnSort by any column

Custom Display Custom Display ExampleExample

Project IssuesProject Issues

• Robust convergence after initial tuningRobust convergence after initial tuning• Customer took ownershipCustomer took ownership

– Minimal continued support neededMinimal continued support needed• Extended project timelineExtended project timeline

– Many software enhancements were included Many software enhancements were included (now part of the base product)(now part of the base product)

• Large model footprint Large model footprint – Bigger than expected (with MISO and Bigger than expected (with MISO and

Canada)Canada)

Project NotesProject Notes

• External model updatedExternal model updated– Import large PSS/E modelImport large PSS/E model– Use automated Model Merge function to Use automated Model Merge function to

replace the externalreplace the external

• PNAA is now used for regional trainingPNAA is now used for regional training seminarsseminars– Includes joint Black Start studiesIncludes joint Black Start studies

• Model sharing with neighborsModel sharing with neighbors– Import/export PSS/E and CIM/XMLImport/export PSS/E and CIM/XML

Keys to SuccessKeys to Success

• Force Dependence on SE (drop other Force Dependence on SE (drop other tools)tools)

• Improve Operators Interface (high level)Improve Operators Interface (high level)• Start Small and Expand (quality over Start Small and Expand (quality over

quantity)quantity)• Separate Network Apps from SCADA Separate Network Apps from SCADA

(system, people, process)(system, people, process)

Questions ?Questions ?