Application and Implementation of State Estimator at Idaho Power Company

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Application and Implementation of State Estimator
at Idaho Power Company

• S. Kincic and M. Papic

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Outline

• Background
• Overview of IPCO and its EMS System
• IPC Experience with State Estimator
• Modeling Issues
• SE in Planning
• Conclusions

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1. Background

• The EMS project has been initialized by Grid
  Operations and Planning following the
  recommendations of the US/Canada outage task
  force on the August 2003 blackout.

• The Project addresses the NERC and WECC
  requirements for EMS functionality identified
  from the August 14th Blackout as well as improved
  coordination with additional Off-Line Planning
  Functions.

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Background
NE Blackout TF Recommendations

• Recommendation 22 Evaluate and adopt better
  real-time tools for operators and reliability
  coordinators
• Recommendation 24 - Improve quality of system
  modeling data and data exchange practices
• NERC should work with the regional reliability
  councils to establish regional power system
  models that enable the sharing of consistent and
  validated data among entities in the region.
  Power flow and transient stability simulations
  should be periodically benchmarked with actual
  system events to validate model data.

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1. Background

• Installation and complete modeling of the new EMS
  has been completed entirely by IPCO EMS team
• Project completed in two phases
• Phase I Implementation of SE and advanced
  applications (May 2005)
• Phase II Cutover to the new SCADA (May 2007)
• SE tuning has been accomplished throughout 2007

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2. System Overview
Company

• Covers 24.000 sq. miles

• Peak 3300MW

• Net importer of energy

• 17 plants

• Shared ownership of three coal fire plants

• 4,600 miles of transmission lines

• 18,000 miles of distribution lines

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2. IPC System Model

• Planning Model (bus-branch representation)
• EMS/Dispatching Model (node-breaker
  representation)
• Models Accuracy and Validation
• Inter-Utility Data Exchange
• The system representation at any given time
  includes the static data (network topology) and
  the system conditions (loads, interchanges,
  flows)
• Wide System Model (WSM)

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EMS System Configuration

• Windows Based

• One pair of servers for SCADA and Generation
  Application

• One pair of servers for SE and Advanced
  Application

• One pair of servers for ICCP data

• One server for DTS

• Two modeling Servers

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EMS System IPC Data Exchange
IPC
PNSC
PAC
BPA
SPPC
EHVDP
CMRC
NWE
RDRC
PGE
PGE
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3. State Estimator

• Operates on PNSC model (North West WECC)

• Model Includes
• 8000 buses (1400 measured)
• 5000 lines
• 4000 substations
• Receives about 15000 analogs and statuses

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3. State Estimator

• SE runs every 300 sec.
• RTNET includes SE and RTCA
• STNET includes PWRFLOW and CA
• After every State Estimate , the base case is
  monitored for violations
• Real Time CA runs every 300 sec.
• Base Case used for STNET (outage schedule)

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4. Modeling Issues

• Planning model is used as a source of line and
• transformers parameters- occasionally
• conversion of p.u. in percentage omitted

• SE uses breaker oriented model-terminals of every
• device are attached to two or three nodes.
• Assignment of device to incorrect node
  topology
• error

• Series capacitors composed of modules that can be
• Inserted and bypassed separately (often non-seen
  on company one line). If represented as a single
  device- Significant power flow error

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4. Modeling Issues

• Breaker oriented model- over 30.000 breakers.
  Status of breakers required or topology error if
  breaker is in wrong position. Maintenance is
  required
• Field changes have to be modeled- difficulty in
  obtaining new data
• Mapping of the measurements into the model if the
  name change- composite key broken

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• Bus configurations
• need attention

SCADA model
NETWORK model
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• Wrong direction of
• measurements

breaker
100 MW
100 MW
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100 MW
transformer
100 MW
100 MW
LV
HV
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• Load model

Load model-time dependant schedule for operating
area
Individual loads follow the same pattern
No load diversity
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Detailed load model
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5. Application of
SE in Planning
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Translation of dispatching (breaker to breaker)
model into the planning model
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6. Conclusion

• Vendors provide operational structure

• Utilities have to address modeling issues

• The flow of measurement data among
• utilities has to be established

• Idaho Power Company has successfully
• accomplished these tasks

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What Next?

• Continue working and improving IPCO model.
• Developing a process of updating IPCO model with
  external transmission facilities.
• Participating in the development of the WSM
• Further Validating of SE, STNET and CA results
• Implementing of Metrics for SE Evaluation ()
• Integrating of PMU data into IPCO SE.
• Start using POM to evaluate critical
  contingencies and develop a mitigation plan when
  the contingency occurs. ()