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    Distribution System Planning in the Northwest Future Challenges,

    Deficiencies, and Solutions/OpportunitiesSolutions/Opportunities

    S. S. (Mani) VenkataNorthwest Energy System Symposium

    (NWESS)Seattle, WA

    February 22, 2007


    Overview of Distribution Systems

    Planning Objectives

    Future Challenges

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    Current Deficiencies


    Transmission and Distribution Electric Systems

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    Distribution System

    Distribution Substation

    Power Transformers: Single banked or doubled bank with 10/12.5 to 52/104 MVA ratings


    Switchgear: Breakers, switches,...

    Distribution Substation

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    Compensating Devices: Regulators, capacitors,...

    Control and monitoring Devices: CTs, VTs,....

    Computers and communications links

    Remote terminal units (RTUs)

    Distribution System Line EquipmentPrimary feeders three-phase) Laterals (three- or single-phase)Protective devices: Automatic Circuit Recloser (ACR),

    Distribution System Planning - 6 2007 KEMA Inc.

    ( ),sectionalizers, fuses, capacitors (150- to 1200-kvar) Distribution transformers (pole-mounted, padmount, commercial subsurface)Secondary services

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    3277 Electric Distribution System UtilitiesDistribution Systems is neglected step child Distribution System serves 131 Million Customersof Distribution lines 3.1 Million miles Electrical infrastructure is ageing rapidly

    U. S. Distribution System Size and impact

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    g g p yTotal Revenue $256 billion / yearAverage cost of retail energy sales $0.074 / kWhAverage cost of power generation $0.041 / kWhTotal cost of distribution losses $6.9 Billion / year

    U. S. Distribution System Size and impact

    Most of the customer complaints are on the distribution system since they are served directlyImpacts customer satisfactionAmount of data handled is at least 10 times higher L d id l di t ib t d

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    Loads are widely distributed Analysis and models needed are different for distribution systemsSystem losses (about 6%) are twice to four times higher than on the transmission Most of the infrastructure needed for delivery of power is on the distribution system

    The State of Washington Approximately 3.1 million customers served by:

    Investor Owned, Cities, Cooperatives, REAs, and Public Utility DistrictsFour Large PUDs

    Seattle City Light (374,000)Snohomish PUD (301,000)Clark Public Utilities (174,000)

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    Clark Public Utilities (174,000)Tacoma Power (163,000)

    Three IOUs AVISTA Corp (338,000), Pacific Corp (122,000), and Puget Sound Energy (1,002,000)

    46 remaining PUDs and Coop utilities Average: 14,312 customers eachRange: 46 to 52,015 customers each

    Distribution System Philosophical considerations

    Distribution systems are complex and capital intensive

    Distribution Planning is a very complex process

    Multiple objectives and constraints

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    Changes in customer base are occurring rapidly

    Opportunities that enhance planning capabilities

    How do we adapt to the changes?

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    Overall Planning ObjectivesMultiple objectives

    Affordable power delivery Adequate CapacityAdequate Reliability Acceptable Voltage quality

    Normal conditionsSystem efficiency, reliability, security

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    Cost-effective design solutions (minimized total costs)Minimum risk investmentsVoltage regulation/load balancingRe-configuration of system

    Emergency conditionsAdequate capacity and performanceLoad transferRestoration

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    Planning Constraints

    Multiple constraintsEconomic (long range total cost minimization)Technical (voltage quality, capacity & reliability)Societal (total consumer expectations)Environmental (UG dispersed generation)

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    Environmental (UG, dispersed generation)

    Planning and Design Studies

    System performance and optimization studies

    Short- and long-range load forecasting

    Unbalanced three-phase power flow

    Fault or short-circuit analysis

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    Voltage Regulation

    Power quality (voltage sags and harmonics)

    Transient analysis

    Loss minimization and efficiency studies

    Motor starting (cold load pickup)

    Relay coordination

    Transformer load management

    Conservation voltage regulation analysis

    Planning and Design Studies

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    Reliability assessment

    Cost-benefit and risk analysis

    Operation contingency studies

    Small Area Forecasting

    Planning Challenges from Planners Perspective

    Evaluation of alternative futures Dispersed generationAuto-sectionalizing schemes.

    Efficient use of data base technologiesAM/FM/GIS systems

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    AM/FM/GIS systems Customer, system, planning and operational data

    information interfaces

    Compliance with RegulationsFERC, NERC, PUC, county, city, ...

    Compliance with standardsANSI, OHSA, UL, NEMA, IEEE, IEC, NESC and NEC,..

    Future Challenges for Distribution Planning

    Changing consumer load characteristics, consumer services, and reliability expectations.How to model and plan for the addition of more dispersed distribution generation?How to plan and model the addition of automatic metering interfaces?

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    gHow to use the new metering data to further improve distribution efficiency, reliability assessments, voltage modeling, and outage management?How to model, interface, and use the increase in size of data structures for consumer information like GIS and CIS?

    How to apply and analyze outage management data using remote SCADA sensing instead of phone calls?Higher efficiency standards enacted by the State of Washington (Initiative-937) require greater application of conservation and renewable resources

    Future Challenges for Distribution Planning

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    resources. The distribution system will be asked to pay more attention to system losses.Need for end-use load control devices and control (Grid Smart)

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    Conservation voltage regulation is becoming more popular and requires a higher degree of modeling, data collection, and monitoring.Performance penaltiesTime of use metering

    Future Challenges for Distribution Planning

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    Load control applicationsEvaluate reliability penalties for poor reliability as rebate to consumers How to optimize the total cost of the consumer for distribution system delivery for system losses, voltage control, and future infrastructure needs?

    Problems Unique to Pacific Northwest

    Variety of utilities: very small to large

    Mostly municipal utilities with unique issues

    Many of them deal with distribution only

    Distribution System Planning - 20 2007 KEMA Inc.

    Small utilities have very limited resources

    Each utility may have unique objectives and constraints to contend with

    How do utilities cooperate to solve common problems related to distribution planning?

    Current Planning Practices in Pacific Northwest

    1. Many small utilities have only one planning engineer

    2. Planning and design is performed by consultants and others.

    3. Few have GIS let alone GIS and CIS interfaces.

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    4. Distribution system load forecasting is based on historical trends and short term.

    5. T&D energy efficiency is routinely not addressed.

    6. System metering is mostly demand meters and seldom includes both watt and var 15 minute demands.

    7. Rates analysis is performed routinely but not used by planners.

    8. Distribution system modeling is simplified and typically does not incorporate the entire distribution system and is not interfaced with GIS.

    Current Planning Deficiencies in Pacific Northwest

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    9. Transformer load management and related applications are seldom realized.

    10. System reliability modeling is primarily a historical based approach.

    Current Planning Deficiencies in Pacific Northwest

    11. Few optimization applications of distribution system reliability, losses, and infrastructure

    12. Consumer load and dispersed generation 8760 hour profiles not addressed.

    13. Few model the total system voltage drop from th b t ti t th i t

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    the substation to the consumer service entrance (main feeders, laterals, distribution transformers, and secondary)

    14. No ability to evaluate alternative impacts on the distribution system for changing consumer load patterns, load densities, and cost of losses.

    15. No predictive reliability modeling

    Current Planning Deficiencies in Pacific Northwest

    16. Power flow analysis capable of radial feeder operation only

    17. Reliability, system efficiency, and capacity are modeled separately

    18 Long range distribution system expansion planning

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    18. Long range distribution system expansion planning using spatial load and land use forecast is not performed

    19. Few planning applications for CVR, efficiency evaluations, reactive var management optimization

    20. In ability to change design practices to achieve long range efficiency objectives

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    Human Resource Deficiencies in U. S.

    The statistics for electric energy/power engineering are even more discouraging.

    Only 75 out of 300 plus universities offer some sort of power curriculum.

    We only graduate about 500 B. S., 200 M. S.

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    y g ,and 50 Ph.D. energy engineers.

    Because of the lack of short-and long term demand profiles, the future of the human resource needs is uncertain and unclear.

    Technicians and Operators Needs

    The shortage of operators and technicians is an equally serious problem.

    The education and training of such personnel can be addressed by community colleges and vocational institutes working closely with industry state and

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    institutes working closely with industry, state and federal agencies.

    Opportunities for Planning Improvements and Innovation

    Transformer Load Management

    Three-Phase Load Flow

    Network Modeling

    CIS d GIS i f

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    CIS and GIS interface

    Predictive Reliability Analysis

    Model total system from Substation to Consumers meter

    Model 8760 h load and generation data

    Opportunities for Planning Improvements and Innovation

    Apply optimization to system infrastructure improvement decisions

    Prioritization and Risk management decision tools

    Asset management optimization tools

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    Asset management optimization tools

    Reliability data analysis and modeling

    Long range and horizon planning tools

    Total system efficiency modeling and decision tools

    New Methods and Tools

    Database bases and managementCIS, Corporate, GIS, planning

    Load ForecastingHeuristicsEmpirical formulas

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    SpatialIntelligent methods

    System and Optimization StudiesSystem Design (minimize losses, total system cost)System Operation (maximize reliability and minimize losses)Reactive Load Management (capacitor switching and locations)

    Reliability Assessment (normal, contingency, and storm conditions)

    Probabilistic methodsFailure Mode Effects Analysis (FEMA) Markov analysis

    New Methods and Tools

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    Monte Carlo analysis

    Automated PlanningAM/FM/GIS systemsPerformance and cost analysis

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    Recent Trends and Developments

    Dispersed generation and storage integrationAutomated Metering Interface (AMI)Automated Meter Reading (AMR)Asset managementPerformance Based Rates

    Distribution System Planning - 31 2007 KEMA Inc.

    Performance Based RatesRisk assessment and managementCircuit of the Future (distribution)Utility of the FutureAdvanced distribution automation

    New Technological Developments

    Integration of power and IT infrastructures

    Composite poles and conductors

    Massively deployed sensors for automation

    Vacuum fault interrupters (RAR RCS)

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    Vacuum fault interrupters (RAR, RCS)

    Fault current limiters: solid-state and superconductors)

    AMR and AMI

    Enterprise Level IntegrationTimely access to information critical for Planning, Engineering, and


    Distribution ManagementMWMOMSGIS

    T&D Planning & EngineeringAsset MgmtMaintenanceMgmt


    Power Procurement & Market OpsPlanning &Forecasting

    Bidding &Scheduling

    Trading &Contracts




    DMST&D Operations

    Executive Dashboards

    Customer ServicesMDMS CIS BillingCall Center


    n Integration

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    Advanced Metering Infrastructure

    Communications Infrastructure



    Plant Controls

    Substation Automation

    Assignment for TodayBreak out sessions

    Discuss and determine what are the 3 biggest problems facing distribution system planners in the northwest and why

    What are the 3 best solutions you have found in your work practices to solve some of the problems

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    your work practices to solve some of the problems you find?

    If you could have new tools or information to improve distribution system planning, what would it be?

    Can a Northwest WG be formed to address these issues?


    [1] G. W. Ault, C. E.T. Foote, and J. R. McDonald, Distribution System Planning in Focus, IEEE Power Engineering Review, January 2002, pp.60-63. [2] H.L.Willis, J.E.D. Northcote-Green, and H. N. Tram, Computerized distribution planningData needs and results with incomplete data, IEEE T P D li l PWRD 2

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    IEEE Trans. Power Delivery, vol. PWRD-2, pp. 1228-1235,1987.[3] T. Gonen and I.J. Ramirez-Rosado, Review of distribution system planning models: A model for optimal multistage planning, IEE Proc. C, vol. 133, no. 7, pp. 397-408, 1986


    [4] S.K. Khator and L.C. Leung, Power distribution planning: A review of models and issues, IEEE Trans. Power Systems, vol. 12, pp.1151-1159, 1997.[5] T.W. Berrie, Electricity Economics and Planning 1st ed London: Peregrinus 1992

    Distribution System Planning - 36 2007 KEMA Inc.

    Planning, 1st ed. London: Peregrinus, 1992.[6] G.W. Ault, A. Cruden, and J.R. McDonald, Specification and testing of a comprehensive strategic analysis framework for distributedgeneration, in Proc. IEEE PES Summer Meeting 2000.


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