Austin Energy Elevated Requests for High Reliability Service South West Electric Distribution Exchange (SWEDE) May 8, 2015 David Tomczyszyn, P.E. – Distribution Design North Manager

Austin Energy 2 8 th largest community-owned electric utility serving 435,000 meters and a population of approximately one million 437 square miles of service area covering City of Austin, Travis County and portions of Williamson County. Owns and operates generation, transmission, and distribution System peak load MW Annual budget - $1.51 billion First public power utility in Texas to earn Diamond Level recognition (2011) as a Reliable Public Power Provider (RP3) by the American Public Power Association (APPA); again in 2013 (eligible every 2 years) ISO Certified T&D Organization since 2007 Austin, Texas

Definitions Emergency Power - “an independent reserve source of electric energy that, upon failure or outage of the normal source, automatically provides reliable electric power within a specified time to critical devices and equipment whose failure to operate satisfactorily would jeopardize the health and safety of personnel or result in damage to property.” - IEEE Std Optional Standby Systems – ”Those systems intended to supply power to public or private facilities or property where life safety does not depend on the performance of the system. These systems are intended to supply on-site generated power to selected loads either automatically or manually.“ – NEC, NFPA

Definitions Automatic Throw Over (ATO) / Automatic Transfer Switch (ATS) – a device which allows for the transfer of electric power from a preferred source to an alternate source if the preferred source loses power. Open Transition – break before make Close Transition – make before break Transfer Time – time required to switch from the preferred to the alternate source OR the alternate source back to the preferred source Retransfer – automatically switching back to the preferred source from the alternate source when the preferred source is restored 4

How does an ATO work?

Types of Customers 6 Government Hospitals and Nursing Homes Data Centers Corporations & Technology Companies Schools Water Treatment Plants

Data Center Tiers 7 Tier LevelRequirements 1 Single non-redundant distribution path serving the IT equipment Non-redundant capacity components Basic site infrastructure with expected availability of % 2 Meets or exceeds all Tier 1 requirements Redundant site infrastructure capacity components with expected availability of % 3 Meets or exceeds all Tier 2 requirements Multiple independent distribution paths serving the IT equipment All IT equipment must be dual-powered and fully compatible with the topology of a site's architecture Concurrently maintainable site infrastructure with expected availability of % 4 Meets or exceeds all Tier 3 requirements All cooling equipment is independently dual-powered, including chillers and heating, ventilating and air-conditioning (HVAC) systems Fault-tolerant site infrastructure with electrical power storage and distribution facilities with expected availability of %

Transfer Times 8 Type Emergency Power Restoration Time – NFPA UBasically Uninterruptible (UPS Systems) 1010 sec 6060 sec sec MManual stationary or nonautomatic - no time limit Standby Power - Transfer TimesAE Dual Feed Services Determined by Customer EquipmentDirect or Dedicated Feeds 1-3 secPowell or S&C PME ATO 7-10 secVista ATO UPS Source: APC – Schneider Electric Flywheel Source: VYCON - Schneider Electric

High Level Dual Feed Process 9 Planning reviews existing system loads to determine sources, recommends a preliminary feeder routing, and Provides customer with an order of magnitude estimate. Design & System Engineering design both the on-site and off-site services, requisition equipment and collect payment. Customer requests have ranged from MVA with most services falling between 2-12 MVA. AE reviews request with the customer and recommends the best type of service (dedicated feeds, direct feeds, multiple ATOs, single ATOs, standard service, etc..) Construction, System Engineering, Control Engineering set, install, and commission the service.

Single Tank Vista ATO Source: S&C

Single Tank PME ATO Source: S&C Example: PME – 9 Source Transfer

PME ATO & Transformers 12

Dual Tank ATO 13 Source: Powell

Powell ATO & System VI PM 14

2 Direct Feeds & System VI PM 15

Cost of Dual Feed Service 1)Initial assessment fee - $6000 per site 2)Capacity reservation & maintenance Fee - $3,100/MVA per month 3)Facilities design and construction – cost* + 15% per fee schedule - approximately $250K to $1M+ per installation depending on distance to source and type of service requested * Effective Oct 1 st, 2014 AE line extension policy was changed to 100% of estimated cost for labor and material 16

Design & Operations  Do you need redundant transmission feeders, power transformers, circuit routing, ATOs, distribution transformers, etc..?  Will the customer have direct OR dedicated feeds?  Should you add a bypass switch to your design for maintenance purposes?  Should you coordinate your ATO transfers with your substation breakers to ride through the 1 st reclose?  Do you manually do a retransfer or do you allow the ATO do it automatically? 17

Lessons Learned  Multiple dual feed studies for real estate companies  Data center operator competition  Maintenance program / staffing levels  Customer’s ability to move load when two feeds are provided at one time – consider a contract  Do you need communication to monitor your equipment? 18

Questions? David Tomczyszyn, P.E. Office: