Distribution Companies – Where the Network Meets the Load Merlin Raab Renewable & Energy Efficiency Sr. Consultant Wisconsin Public Service Corporation

Distribution Companies –Where the Network Meets the Load

Merlin Raab

Renewable & Energy Efficiency Sr. Consultant

Wisconsin Public Service Corporation

October 02, 2012

Distribution Companies – Where the Network Meets the Load2

Agenda

• Overview of Distribution Company• Distribution in the Value Chain• Responsibilities of Distribution Company• A Typical Day• Challenges


Electric Distribution Utility-1990


Electric Distribution Utility-2012


Physical Characteristics

• Electric distribution company begins at the substation where the electricity is “stepped down” to distribution voltage

• Lines feed out from the substation (typically in the range of 7,200 to 25,000 volts)

• At customer locations, electricity is “stepped down” again to a usable voltage – 120/240 volts for residential customers


The System Itself

• System has to be designed and constructed to:– Ensure proper voltage levels– Ensure equipment such as lines and transformers do not

overheat when peak flow occurs (hot summer day)– Withstand the elements – weather, lightning, etc.– Handle additional load such as new customers’ load or

existing customers adding load• To do this, engineers develop computer models of the

distribution system to conduct load flow analysis


Distribution System Modeling / Analysis

Output from load flow analysis is used for:– Determining system efficiencies – present and future– Determining if equipment overload conditions exist– Determining high-loss line sections– System deficiencies during emergency switching or

temporary load transfers– Over-current protection plans– Feasibility of large load additions– Proper capacitor placement– Long-range planning – timing of substation reinforcements


Distribution System Modeling / Analysis

Increased emphasis on off-peak electricity usage will change the shape of our typical load curve and our computer model

– Electric vehicles charging during off-peak hours– Customers shifting other appliance loads to

off-peak hours


Load Cycle of Substation Transformer

50%

100%

150%

12 PM

6 AM NOON

6 PM 12 PM

Actual Load

Equipment Rating

- Usually repeats every 24 hours

- Load fluctuates throughout the day

- Usually one peak period in the day


Distribution in the Value Chain

• Supply produced at central plant or distributed resources

• Central station supply is dispatched to the “Grid” and then into one of three grids: ERCOT, WECC, and Eastern Interconnection

• Transmission lines transmit energy to the market• The market matches supply offers and load bids• Control operators oversee transfer of energy to load

serving distribution companies• Energy is “stepped down” to a distribution area and

then further “stepped down” to a customer site


NERC Interconnections


NERC Regions and Balancing Authorities


Generation

GenerationGeneration







6,009 Generators

MISO MarketMISO Market Distribution

Distribution

264 Load Zones

Distribution

DistributionDistribution




Distribution

Distribution

Offers

MW Schedules/Dispatch

Bids

MW Schedules

Prices

Energy

Dollars

Energy

Dollars

MISO Market in General

• Central bid/offer/settlement


Responsibilities of DistributionCompany – “Obligation to Serve”

• Retail Functions• Meter to Cash• Customer/Government

Relations• Construction/maintenance

• Reliability• Engineering studies• Line clearance• Storm restoration• Power continuity/quality

• Safety• Public• Employee

• Economic Delivery• Dispatch decisions• “Cost per”

• Compliance• PSC quality standards• NERC reliability (Local

Balancing Authority)• FERC• OSHA

• Environmental andCorporate Stewardship• Environmental principles• Hazardous waste/site run-

off management• Community outreach


A Typical Day in 1990

• Monitor system to ensure adequate amount of generation to serve load; contract for additional generation if needed

• Voluntary compliance with NERC & regional reliability standards

• Build new and maintain distribution system• Minimal number of customer-owned generators

putting power back to the grid• Respond to power outages that are received via

phone from customers


A Typical Day in 1990 (continued)

• Customers who experience outage remain without power until line electricians travel to the site to address cause

• Customer’s receive information on restoration times from radio & TV

• Send out meter readers who bring back reads for use by customer billing

• Customers generally not concerned with the timing of use of electricity

• Appliances, such as dishwashers and refrigerators, run at will

• The number of customers behind on their bill is small and demographically homogeneous


A Typical Day in 2012

• Monitor system real-time and purchase power on the MISO market to match load requirements or institute demand control

• Limited customer-owned renewable generation putting power onto the system requiring the distribution company to adapt systems to handle it

• Systems used to proactively determine location of outages and dispatch repair crews

• Customers receive restoration information via social media

• Limited use of automated switches installed on distribution system isolate faulted sections of line and automatically restore power to a large portion of customers without power


A Typical Day in 2012 (continued)

• Mandatory compliance with NERC & regional reliability standards with threat of financial penalties

• Meters read from a central location automatically through communications network. Customers have access to unbilled energy consumption via web-portal

• Distribution system modernization technology /smart meters allow customers to make full advantage of time sensitive rates?

• The number of customers behind on their bill growing and demographically diverse


Prices to Devices

Source: EPRI

Figure 1. Dynamic Energy Management Infrastructure for a Commercial Building


Challenges

Increased number of renewable source generators on the distribution system & possibly micro-grids

• Changes load flow analysis (computer model) due to electricity flowing back to the system

• Requires modifications to equipment on those circuits, such as over-current protection equipment and conductors

• Requires modifications to operating procedures for safety

• Net-metering: Who pays for maintaining the system?


Challenges

•Distribution companies will need to make significant investments in equipment to accommodate increased DG and increased off-peak usage•Limited “Smart System” benefits to rural customers•Regulatory Uncertainty regarding “Smart system investments”

•Who bears the risks?•Opt out vs. Opt. in pricing options•Security & privacy issues•EMF concerns


Challenges

• Customer• Keep costs down (low rates) amid cost pressure• Help understand rate vs. bill – energy optimization

• Shareholder• Maintain attractive, risk-adjusted return

• Employee• Graying of industry / training / retention /

cost reduction


Documents

Distribution Companies – Where the Network Meets the Load Merlin Raab Renewable & Energy Efficiency Sr. Consultant Wisconsin Public Service Corporation