Utility Forecasting

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UtilityForecasting Planning
MADRI Meeting March 7, 2006
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Purpose

• This presentation is intended to be a general
  outline of utility forecasting and planning
  techniques not specific to any one company.
• It is, however, intended to represent a utility
  that is a PJM member, and is following a process
  that works with the PJM planning regime.

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Planning Criteria

• A utilitys planning criteria are intended to be
  a guide to provide for the safe, reliable and low
  cost development of the utilitys electrical
  system as loads increase and reinforcements
  and/or new facilities are required.

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Basic Principles

• With all facilities in service
• Load must be within normal equipment ratings
• Must provide acceptable voltages

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Basic Principles

• With the outage of any single piece of equipment
  (N-1 Criteria Violation)
• Affected load must be within the emergency rating
  of the remaining facilities
• System must provide minimum emergency voltages

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Basic Principles

• N-1 criteria are applied in a similar fashion to
• Substations
• Distribution Facilities
• Subtransmission Facilities
• Transmission Facilities

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Basic Principles

• Transmission Planning Criteria
• Goes beyond N-1
• N-2 (After the N-1 outage and re-adjustment, loss
  of an additional element.)
• Towerline outages
• Stuck breakers

Transmission planning criteria are more
restrictive than operating criteria to account
for potential new generation, and network
facilities forecasted and unplanned outages.
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Distribution Planning

• Load Forecasting
• Substation
• Feeder
• Distribution Circuit Reinforcement
• Ratings
• N-1 Criteria
• New Business
• Connected vs. Estimated Loads
• Load Build-up Schedules
• Load Shifting

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Substation Forecast/Planning Process Diagram for
a Typical Utility
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Substation Forecast/Planning ProcessData
Collection
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Substation Forecast/Planning Process Data
Collection

• CMMS Peak Load Data
• MV-90 Remote Metering
• Substation Data Concentrators
• Inspection Data
• Data Scrubbing

• Adjustments
• Voltage Reduction, Cogen, etc.
• Reference Data
• Station Type, Reactive, Power Factors, Feeder
  Info, etc.
• Load Transfers
• Historical Trends
• Peak Adjustments

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Substation Forecast/Planning ProcessWeather
Normalization
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Substation Forecast/Planning ProcessWeather
Normalization

• Weighted Temperature-Humidity Index (WTHI)
• 3-Day Heat Build-Up
• 10-5-2 Weighting Factors
• Normalization Standard
• 50/50 Historical Probability
• 84 Degrees WTHI

• Normalized Peak Selection
• Load vs. WTHI Correlation
• Exclusion of Data Points Below 73 Degrees WTHI
• Exclusion of Non-Trend Data Points
• Current Year Weather Sensitivity
• 5-Year Weather Sensitivity

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Substation Forecast/Planning ProcessSubstation
Area Forecasts
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Substation Forecast/Planning ProcessSubstation
Area Forecasts

• Growth Factors
• General Growth Load growth of existing and
  small additional customers is generally
  consistent with historical trending
• Specific Growth Load growth attributable to
  major new business projects greater than 300 kW

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Diversified Specific Growth

• Adjusted for
• Over-estimation of Loads
• Load Profiles
• Delayed Project Completions
• Customer to Feeder Coincidence
• Feeder to Substation Coincidence

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Coincidence Factor

• Substations feed a number of different types of
  load
• Not all of the load will peak at the same time
  (diversity)
• Expect any implementation of time-of-use or RTP
  tariffs to cause interval customers to
  change/modify load patterns

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Substation Forecast/Planning ProcessSubstation
Area Forecasts

• Forecast Worksheet
• Historical Trending
• Feeder Peak Synthesis
• Forecast Performance
• Short Range Forecast
• 4-Year Forecast
• Long Term Forecast
• 9 Scenarios

• High Tension Service Customer Forecasts
• Developed by utility
• Area (Switching Station) Forecasts
• Coincidized Substation Roll-Up
• System Forecast Roll-Up
• Coincidized HV Substation Area Forecast Roll-Up

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Substation Forecast/Planning ProcessSubstation
Area Planning
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Substation Forecast/Planning ProcessSubstation
Area Planning

• Substation Area Capacity
• Firm N-1 Criteria
• Includes Automatic ICT Transfers
• Capacity Processing
• Load vs. Capacity Analysis
• Load Relief Modeling
• Power Factor Correction
• Load Transfers
• Dispersed Generation

• System Reinforcement Modeling
• Interstation Capacity Ties
• Station Reinforcement
• New Station
• Generation (As Permitted)

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Feeder Forecast ProcessData Acquisition

• Substation Operators collect data during station
  inspections via a Mobile Data Terminal (MDT)
• Data is electronically uploaded into CMMS
• Data is extracted into spreadsheet
• Data is scrubbed no data, broken meter, tie
  recloser operations, etc.
• Summer peak load is selected and utilized to
  develop the individual feeder forecasts

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Feeder Forecasting ProcessLoad vs. Capacity
Analysis

• Peak data is used for Station Feeder Forecasts
  (Feeder Utilization)
• Data is processed to evaluate overloaded circuits
• Forecast sheets are used when a New Business Plan
  of Supply is submitted
• Is capacity available?
• If not, how can circuit be relieved?
• Reinforcement jobs and New Business jobs are
  tracked on the Station Feeder Forecast sheets

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How Do Projects Emerge?

• Individual substation overloads are not as
  critical if sufficient ties exist
• Greatest concern - area overloads consisting of
  two (2) or more substations
• Could cause cascading overloads and area outages
• Time to reinforce when area overloads are present
  or could reasonably be expected to occur in the
  near future

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New Business

• Division Planners are typically concerned with
  new business projects 300-kVA and greater
• Voltage / Service characteristics can range from
  secondary to sub-transmission (277/480 volts up
  to 69-kV)
• Types of New Business can vary from Network
  Service to Substation / High Tension service

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Transmission Planning

• Entity Load Forecast
• Regional Transmission Expansion Planning (RTEP)
  Process
• Lead by PJM and coordinated with Transmission
  Owners
• Incorporation of utilitys TD Planning results
  into PJMs RTEP Process, PJM will begin zonal
  forecasting utility loads this year
• Baseline Reinforcements
• Merchant Generation/Transmission Interconnections
  Reinforcements
• Analyses Tools
• Short Circuit
• Load Flow
• System Stability
• LOLP (Loss of Load Probability)
• Operations Support

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Entity Load Forecast

• The Entity Load Forecast is an independent
  forecast of summer peak, performed by PJM
• Used to set Zonal Scaling Factors in eCapacity
  and sets capacity obligations for all LSEs
• Relates growth in the PJM normalized peak to the
  U.S. economy (Gross Domestic Product)
• This load is allocated to specific nodes using
  the various utilitys Distribution Substation
  Forecasts

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Any Questions?