Application and Implementation of State Estimator at

Idaho Power Company

S. Kincic and M. Papic

Outline

1.1. BackgroundBackground

2.2. Overview of IPCO and its Overview of IPCO and its EMS SystemEMS System

3.3. IPC Experience with IPC Experience with State State EstimatorEstimator

4.4. Modeling IssuesModeling Issues

5.5. SE in PlanningSE in Planning

6.6. ConclusionsConclusions

1. Background

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.

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.

1. Background

Recommendation 22 – Evaluate and adopt better real-time tools for operators and reliability coordinatorsRecommendation 24 - Improve quality of system modeling data and data exchange practicesNERC 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.

NE Blackout TF Recommendations

1. Background

Installation and complete modeling of the new EMS has been completed entirely by IPCO EMS teamProject 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

2. System Overview

Company:

Covers 24.000 sq. miles

Peak 3300MW

Net importer of energy

17 plantsShared ownership of three coal fire plants

4,600 miles of transmission lines

18,000 miles of distribution lines

British Columbia Alberta

Washington

OregonIdaho

Montana

W yoming

Colorado

Utah

Nevada

California

Arizona New Mexico

Mexico

12

MONTANA

UTAH

WASHINGTON

NEVADA

OREGON

WY

Geographic Location of I daho External Paths

2. IPC System Model

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

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

EMS System: IPC Data Exchange:

PNSC

RDRCCMRC

IPC

PAC

BPA

SPPC

NWE

EHVDP

PGE

PG&E

3. State Estimator

Operates on PNSC model (North West WECC)

Model Includes: 8000 buses (1400 measured)5000 lines4000 substationsReceives about 15000 analogs and statuses

3. State Estimator

SE runs every 300 sec.RTNET includes SE and RTCASTNET includes PWRFLOW and CAAfter every State Estimate , the base case is monitored for violationsReal Time CA runs every 300 sec.Base Case used for STNET (outage schedule)

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 everydevice are attached to two or three nodes. Assignment of device to incorrect node – topologyerror;Series capacitors composed of modules that can beInserted and bypassed separately (often non-seen on company one line). If represented as a single device- Significant power flow error;

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

METERINGMW, MVAR

MTie Line to JBRIG

ZBR

to MPSN

Capacitors

REACTORL342

303D302Z

305A 306ASCADA model

METERINGMW, MVAR

M

Tie Line to JBRIG

ZBR

to MPSN

Capacitors

306 A305 A

303 D302 Z

REACTORL342

NETWORK model

Bus configurations need attention;

breaker

100 MW

56 57

HV LV

transformer

100 MW 100 MW

100 MW100 MW

Wrong direction of measurements;

Load model;

Load model-time dependant schedule for operating area;

Individual loads follow the same pattern;

No load diversity;

Operating Area(time dependent

schedule)

Load1

Load2

LoadN

Bas

e 1 +

frac

tion 1

BaseN + fraction

N

Bas

e 2 +

fra

ctio

n2

Detailed load model

Operating Area(time dependent

schedule)

Spring

Winter

Summer

Industrialschedule

Residentialschedule

Irrigationschedule

Commercialschedule

North

NorthSouth

West

East

East

Load

Load

Load

Load

Load

LoadLoad

Load

Load

Load

Load

Load

Load

5. Application ofSE in Planning

Translation of dispatching (breaker to breaker) model into the planning model

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

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 WSMFurther Validating of SE, STNET and CA resultsImplementing 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. (*)