Electrical System Reliability

Presented by Stacy Cheevers,Plant Manager

Terms

Distribution Line: 13,200 volts Transmission Line: 69,000 volts Sub Station: Outdoor structure where voltage is stepped

down or up Switching station: power is only switchedMetal Clad Switchgear: High voltage (13.2kv) breakers Recloser: Circuit breaker in a sub station

Customer to rural COOPSingle feed to plantOutdated and undersized

substation

BWD Electrical System

1985 BWD electrical fire caused rationing

1986 BWD staff had concerns for the reliability of the electrical system

History

System Improvements

1987 electrical upgrade Allgeier Martin1st 480v generator and emergency connection for

intake1st underground high voltage feedersNew Switching Station #1

Need for WTP expansion

1989 conducted interviews for consultant for a 40MGD Plant Expansion

MWH new design engineersVery competent electrical engineerBrought in a new concept: true redundant powerEmphasis put on redundancy and robustness

Combined effort BWD and MWH push CEC for more reliable source

2000 addition of three 2MW generators and underground feed to intake

Allowed for load more efficient shedding program

Next Phase

2004 CEC built Beaver Sub

BWD sold a corner tract at minimal cost

2005 added SS1A and 2nd

feed (underground) to a 2nd intake structure

Multi Phase Expansion

New SUB Adjacent to Plant

2005 New 60MDG Plant 2006 Reconfigured

generators to feed SS#1 2008 2nd 69kv line to

Beaver Sub to complete loop

Multi Phase Expansion

Elm Springs

Prairie Creek

Elm Springs

Prairie Creek

Switching Station Pro

Overhead Cons

Underground Pros and Cons

Very reliable system Very complicated Takes a high skill level to

operate and maintainAssures we are prepared

to stay up and running

Current System

2015 Adding additional generator capacity to ensure an average day’s need can be met

Where We Came From

Where We Are Now

Intakes

After Significant upgrades or changes need for updated coordination study

Revise plant one-linesUpdate Arc Flash program

Don’t overlook

Several Small 480V Generators on AutoStart

BWD has 3 Electricians certified in Thermography

Looking into Ultrasonic detection

Performs Extensive Preventive Maintenance

Replacement

What’s Next

Questions?