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Explore the evolving role of distribution companies in the energy sector, from system design to adapting to new energy trends. Learn about responsibilities, modeling, and analysis processes for efficient load management.
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Distribution Companies –Where the Network Meets the Load Merlin Raab Renewable & Energy Efficiency Sr. Consultant Wisconsin Public Service Corporation October 02, 2012
Agenda • Overview of Distribution Company • Distribution in the Value Chain • Responsibilities of Distribution Company • A Typical Day • Challenges Distribution Companies – Where the Network Meets the Load
Electric Distribution Utility-1990 Distribution Companies – Where the Network Meets the Load
Electric Distribution Utility-2012 Distribution Companies – Where the Network Meets the Load
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 Distribution Companies – Where the Network Meets the Load
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 Companies – Where the Network Meets the Load
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 Companies – Where the Network Meets the Load
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 tooff-peak hours Distribution Companies – Where the Network Meets the Load
150% Equipment Rating 100% 50% Actual Load 12 PM 6 AM NOON 6 PM 12 PM Load Cycle of Substation Transformer - Usually repeats every 24 hours - Load fluctuates throughout the day - Usually one peak period in the day Distribution Companies – Where the Network Meets the Load
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 Distribution Companies – Where the Network Meets the Load
NERC Interconnections Distribution Companies – Where the Network Meets the Load
NERC Regions and Balancing Authorities Distribution Companies – Where the Network Meets the Load
Distribution Distribution Distribution Distribution Distribution Distribution Generation Generation Generation Generation Generation Generation Generation MISO Market in General • Central bid/offer/settlement MW Schedules/Dispatch MW Schedules MISO Market Bids Offers Energy Energy Distribution Dollars Generation Prices Dollars 264 Load Zones 6,009 Generators Distribution Companies – Where the Network Meets the Load
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 Responsibilities of DistributionCompany – “Obligation to Serve” Distribution Companies – Where the Network Meets the Load
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 Distribution Companies – Where the Network Meets the Load
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 Distribution Companies – Where the Network Meets the Load
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 Distribution Companies – Where the Network Meets the Load
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 Distribution Companies – Where the Network Meets the Load
Prices to Devices Figure 1. Dynamic Energy Management Infrastructure for a Commercial Building Source: EPRI Distribution Companies – Where the Network Meets the Load
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? Distribution Companies – Where the Network Meets the Load
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 Distribution Companies – Where the Network Meets the Load
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 Distribution Companies – Where the Network Meets the Load
Questions? Distribution Companies – Where the Network Meets the Load