Shore Station UPS Requirements for the

NEPTUNE Power System

Tim McGinnis

UW/APL

Background

• 2 Shore Stations – each able to individually power to the network, although with possible reduced capability

• West Coast of Vancouver Island– Planned visitor center at Victoria– Existing cable stations at Port Alberni,

Bamfield

• Oregon Coast– Existing cable stations at Nedonna Beach,

Rockaway, Pacific City, Bandon

Local Utility Power Reliability

• 2 Substations, each located about 8 miles away

• Station currently served by 1, possibility of connecting to both substations with a switch

• Several outages of 30-60 minutes per year can be expected – mostly from trees/branches

Cable Station

Public UtilitySub-StationLocations

Nedonna Beach

5 mi

UPS Alternatives

• DC System– Typical for Telecom Systems– Most equipment requires 48 VDC – AC-DC rectifiers supply power to batteries

and equipment – If utility power fails, batteries are always on-

line– 3-8 hour battery life typical, generator optional– DC-AC inverter for critical AC loads (minimal)

Traditional Telecom Power Feed Equipment (PFE)

DieselGenerator480 VAC

DC/DCConverter

48VDC:10kVDC

Ground Bed

480VACControl andSwitching

Step DownTransformer480VAC:240/

120VAC

Utility480VAC

Rectifier/BatteryCharger

48VDCBattery Bank

BackboneCable

DC/DC Convertersand

DC/AC Inverters

Non-Essential

Loads

EssentialLoads

UPS Alternatives

• AC System– Typical for Information Technology, Network,

Hospital, Commercial and similar facilities– Most equipment requires 120VAC– If utility fails, run on battery until generator

starts– 10 minute battery life, typical– One or more generators for AC backup

Typical IT UPS System with a backup generator

DieselGenerator480 VAC

AC/DCConverter

480VAC:10kVDC

Ground Bed

Power Module480VAC

Control andSwitching

Step DownTransformer480VAC:240/

120VAC

Battery Bank

Utility480VAC

BackboneCable

Other Loads

Selection Criteria

• Reliability

• Load Voltage and Power Requirements

• Cost

Reliability - DC

dc system 1

commercialac power

enginegenerator

switchrectifier

N+1

battery3 hours

boostconverter

N+1

commercialac power

rectifierN+1

battery8 hours

dc system 2

W = 9 x 10-10

W = 3.45 x 10-7

Reliability - AC

commercialac power

enginegenerator

transferswitch

ac/dc

battery10 min

ac system

commercialac power

enginegenerator

transferswitch

bypassswitch

dc/ac

W = 3.5 x 10-10

Load Power Requirements

• Expected NEPTUNE Shore Station Load is mostly AC equipment

• Power Estimate – 120 kW total– 100 kW seafloor cable load– 20 kW terrestrial load

• Current Estimates– 48 VDC → 2500 A– 480 VAC, 3Ф → 144 A

Cost

• For Loads < 25 kW– Batteries cost less– Batteries have smaller footprint

• For Loads > 25 kW– Generator costs less– Generator has smaller footprint

Item AC DC

Simplicity X

Reliability X X

Majority of Load Voltage - 120AC X

Load Power Requirement – 200 kW

X

Foot Print Size X

Cost X

Criteria for selecting a UPS System

Conclusions

• Need to learn more about Shore Station power requirements

• Need to confirm reliability/availability data

• Need to learn more about similar installations