Planning Electrical Infrastructure in Changing Times

Peter Marschall, P.E.Associate Facilities Program Coordinator

SUNY ESF, Syracuse, NY

Jeffrey L. Robbins, P.E.Senior Principal Engineer

C&S Engineers, Inc., Syracuse, NY

Presented by:

Learning Objectives

1. Recognize the basic concepts of site electrical infrastructure systems.

2. Evaluate opportunities and means for increasing electrical distribution reliability and their impact on costs.

3. Predict when replacement or modifications of the electrical infrastructure primary components must occur.

4. Explore ways to identify value added components to electrical distribution projects.

Agenda

What Triggers Expansion? Campus Planning & Electrical Infrastructure Site Electrical Distribution 101 System Considerations Cost Reduction Measures Value Added Components Construction Issues Lessons Learned

What Triggers Expansion?

Crisis

Opportunity

Program

Crisis

Failures within electrical system Electrical demand capacity

exceeded No expansion capabilities left

Opportunity

Incorporate infrastructure as part of other projects New buildings Building additions Site beautification projects

Works best if utility master-plan is in place

Program

Starts with a master plan of the utilities Should overlay with campus master plan

Provides for orderly upgrade of systems Can set up series of phases for improvements or

replacement of systems

Makes life easier for the Crisis and Opportunity upgrades

Campus Planning

Open communications with all levels of the Campus

Coordinate with Campus Master Plan Buildings getting bigger with more technology Create tandem utility infrastructure plan if possible

Remember buried infrastructure during surface beatification projects

Electrical Site Distribution 101

Basic Distribution Overview Definitions

Radial Network Loop Primary Selective

Review of different configurations Pros & cons

Basic Distribution Overview

Basic components: Utility service Substation (if required) Distribution switchgear Distribution system

DistributionSwitchgear

Substation

Definitions

Radial: A single simultaneous path of power flow to the load.

Network: More than one simultaneous path of power flow to the load.

Loop: Two paths of power flow to multiple loads that can be sectionalized.

Primary Selective (Dual Radial): Two radial feeders to each load.

Radial Feeder Configuration

Bldg. 1 Bldg. 2 Bldg. 3

Bldg. 6 Bldg. 4Bldg. 5

SubstationUtilityService

MH-5MH-3

MH-4MH-2

MH-1

Splice

Loop Feeder Configuration

Substation

Tie

Bus 1

Bus 2

UtilityService

Bldg. 1

NC NC

NCNC

Bldg. 2

NC NC

Bldg. 3

NC NO

Bldg. 6

NCNC

Bldg. 5

NCNC

Bldg. 4

Primary Selective Feeders

Substation

Tie

Bus 1

Bus 2

UtilityService

Bldg. 1

NO NC

NONC

Bldg. 2

NC NO

Bldg. 3

NO NC

Bldg. 6

NCNO

Bldg. 5

NONC

Bldg. 4

MH-1

MH-2

MH-3

MH-4

MH-5

Splice

Radial Feeder Analysis

Pro Least Amount of

Equipment Least Capital CostSimplest configuration

ConAny one failure will take

out entire feederMany splices, usually in

manholesCannot isolate a single

buildingMost susceptible to wide

spread outage

Loop Feeder Analysis

Pro 2 services to each buildingEasy to isolate buildingsHigh reliability Lower capital cost than

Primary Selective Flexible construction

ConOperation ConsiderationsMore equipment than Radial

FeedersHigher Capital Cost than

Radial Feeders

Primary Selective Analysis

Pro 2 services to each buildingHigh reliabilityEasiest to balance loads

on feeders Isolate main busses for

maintenanceAllows for double-ended

substations in buildings

ConMost amount of splices Time consuming to isolate

1 feederMore equipment that

Radial FeedersHighest capital cost

Hybrid Feeder Configuration

UtilityService

Bldg. 4

Substation

Tie

Bus 1

Bus 2

Bldg. 2

NC NO

Bldg. 3

NCNO

Bldg. 5

MH-1

MH-2 MH-3

MH-4

Bldg. 6

NCNONC NC

Bldg. 1

System Considerations

Reliability How much do we really need?

Expansion Review your Campus Master Plan

Existing distribution What do you have?

Public utilities Coordination

How much Reliability do we need?

How long can any one building be down? Are there critical loads?

Critical experiments Research & development Critical life support (hospitals)

Risk assessment How much is reliability worth?

Reliability of utility company’s service

Review Campus Master Plan

What projects are anticipated that will increase load?

What are your anticipated loads?

Critical nature of facilities? Adding critical life safety Adding research & development

Scheduling of projects?

Where are new facilities going to be located?

Existing Distribution System?

What is the capacity, condition & age? Substation, cables, ductbanks, bldg. transformers

Existing loads and where are they? Load profile Identify choke points in distribution

What configuration exists? Spare capacity in ductbanks? Hazardous material?

Asbestos (ductbanks, fire proof., insulation) PCB’s (Trans., switches, cables, potheads) Lead (cable sheathing)

Public Utility Coordination

What can the utility provide? Service voltage Service capacity Independent services

Any special tariffs? Voltage migration Co-generation surcharges Crossing public thru-fares

Cost associated with any changes? Utility service reliability? Distributed generation on campus?

Additional Considerations

Reliability requirements will drive system configuration Reliability has to be balanced with what you can afford

(cost vs. benefit) Can we and/or should we salvage any of the existing

system?SubstationCablesBuilding transformersDuctbank system

Additional Considerations (cont.)

What voltage should be used? Can the existing voltage be utilized?

Maintain existing substation if adequateMaintain existing building transformersUtilize existing cables

Higher the voltage, smaller cables can be usedCan save moneyMay have to replace all building transformersWhat can campus electrical personnel handle?Larger equipment size

Substation required?

Additional considerations (cont.)

What is the best configuration to use? Again, driven by reliability, followed by cost Radial – least expensive/least reliable Loop – reliable, flexible, expandable, easiest to construct Primary selective – reliable, flexible, allows for double

ended substations in buildings Combination – hybrid system

How will system upgrades/replacement be completed? Single project Phase project Incorporated into other projects

System Sizing

Look at existing loads plus future growth

If substation, transformers should be designed for n+1 configuration for reliability and redundancy Estimated load + 10 MVA 1 – 10 MVA xfmr + 1 – 10 MVA backup, total 2 xfmrs 2 – 5 MVA xfmrs + 1 – 5 MVA backup, total 3 xfmrs

For loop and selective primary systems, each side should be designed to carry full load of circuit

Ductbank Layouts

Configurations: Radial feed – Spline through campus with offshoots to

buildings Primary selective – similar to radial, sometimes with

separate manholes for each feeder. Loop system – loop around campus, try not to double

cable back in themselves for separation.

Existing utilities and electric room locations can dictate layout

Need good utility survey Ground penetrating radar (GPR) good for locating depths

of utilities

3 Loop Distribution

Cost Reduction Measures

First, need to look at cost vs. benefit

Can existing ductbank be reused: In proper location? In good condition? Right size and spares available?

Reuse of existing equipment

Downsize equipment

Voltage level

Construction in phases Build future capacity later

Value Added Enhancements

Sidewalks

Roads

Plaza Areas

Landscaping

Drainage

Communications

Other Utilities

Campuswide metering

Campus Communications

Early and frequent communications with administration, faculty, staff and students. Communications started a year prior to construction Campus briefings:

Outlined goals, benefits, scope, and impact on buildings

Departmental briefings:Focus departmental needs through department liaisons

Individual meetings Emails Websites

Preparation for Construction

Buildings will be shut down!

Required to be unoccupied during construction Impractical and costly in most cases to temporarily power

entire buildings. Some occupancy may be required

Researchers attend to flora and fauna

Try to schedule shutdowns on breaks, summer, holidays

Coordinate temporary work provisions

Schedule shutdowns as early as possible

Temporary Power Provisions

Identify critical electrical loads Department meetings On-line surveys Building walk-throughs with occupants and trades staff Protect critical research Chemical storage

Maintain critical services University police, student health Central receiving, mail Vehicle maintenance and fueling

Expect last minute additions to lists

Construction Issues

With existing radial systems, multiple shutdowns required at most buildings Building shutdown schedule dictated in contract documents

Maintain fire detection and alarm systems

Temporary generators/transformers Backfeed through breakers in existing switchgear Temporary distribution panels

Construction Issues

Campus and building Access, Parking Maintain handicap parking and building access

Coordination with fire department for access

Lessons Learned

Building occupants will consider project a nuisance, however, will soon forget.

Communications is key from concept through construction. Communicate early and frequently.

Have contingency plans during construction.

Plan now to avoid crisis mode or take advantage of an opportunity.

Plan for growth, it will happen.