PPL Gas Insulated Substations: Design Considerations and Lessons Learned

Nicholas Matone – Support Engineer, T&S Standards

Agenda

• PPL Overview • Previous GIS Experience • Present GIS Installations • Mobile GIS Investigation • Design Considerations and Lessons Learned • Latest Developments

PPL Overview

PPL Overview

• Northeast/Central Pennsylvania • 1.4 million customers • 10,000 sq. mi. • Predominantly rural • 500kV, 230kV, 138kV, 69kV transmission

voltages

GIS History

• Early generations of GIS: • Vintage ~1978 GIS (Sunbury Substation)

– Many problems throughout its service life – Catastrophic bushing failure in 2013

• Vintage ~1987 GIS (Wescosville Substation) – Similar problems to Sunbury – Taken out of service in 2012

Project Overview: Sunbury 500kV • Ultimate Build:

Eleven breakers, six lines, two transformers

• Arrangement: Breaker-and-a-Half

• Status: Brownfield • Original scope in

2013: Six breakers, two lines, one transformer (replaced old ASEA gear)

Project Overview: Sunbury 500kV (cont.)

• 2016: Two breakers, one line with ~1700’ of GIL to IPP. • 2017: Add second transformer connection, split

transformer bay

Project Overview: Lock Haven 69kV • Ultimate Build:

Fourteen breakers, eight lines, two transformers, two capacitor banks

• Arrangement: Breaker-and-a-Half

• Status: Greenfield • Original scope in

2016: Twelve breakers, eight lines, two capacitor banks

Project Overview: Lauschtown 500kV

• Ultimate Build: Eleven breakers, six lines, two transformers

• Arrangement: Breaker-and-a-Half

• Status: Greenfield • Original scope in

2017: Two lines, one transformer (near completion)

Project Overview: Sunbury 230kV

• Ultimate Build: Eighteen breakers, eight lines, five transformers

• Arrangement: Breaker-and-a-Half • Status: Brownfield • Original scope for 2018: Thirteen breakers,

four lines, five transformers

Project Overview: Wescosville 500kV

• Ultimate Build: Eight breakers, three lines, two transformers

• Arrangement: Double-Bus-Double-Breaker • Status: Brownfield • Original scope for 2019: Six breakers, two

lines, one transformer

Project Overview: Palooka 230/69kV

• Ultimate Build: 230kV – Twelve breakers, six lines, three transformers 69kV – Fourteen breakers, eight lines

• Arrangement: Breaker-and-a-Half • Status: Greenfield • Original scope for 2019: Nine breakers 230kV,

eight breakers 69kV, Four lines each voltage, two transformers

Mobile Substation Concept

Mobile Substation Intent

• Typically used for planned work, but can also be rapidly deployed for emergencies

• Bypass an entire 230/69kV yard • Programming and most testing complete

before deployment • Easily transportable (no permits)

Key Features

• Relaying+SCADA+RTU built-in to LCC Panels – Allows for an existing control cubicle to be taken

out of service

• AC and DC power supplied from external sources – Keeps weight down

230kV Mobile GIS

230kV Layout

• Two trailers, each with two breakers and three Pfisterer cable terminations – Each trailer would be capable of connecting

up to two transmission lines, and one centrally tapped transformer (refer to one-line)

– Combining the trailers will allow for up to four lines, and two transformers at one site

69kV Mobile GIS

69kV Layout • Two trailers, each with four breakers and four

Pfisterer cable terminations – Each trailer will be capable of connecting up to three

transmission lines, and one transformer (refer to one-line)

– Combining the trailers will allow for up to six lines, and two transformers at one site

Design Considerations and Lessons Learned

Online Gas Density monitoring • Central system to track gas density of all zones • Can provide alerts to slow leaks before reaching

alarm or trip level, so repairs can be planned

Design Considerations and Lessons Learned

Camera System • Makes access to viewports much easier and

convenient • Analog system vs central computer system? Analog

provides direct connection, whereas a central computer could provide more convenience

Design Considerations and Lessons Learned

Additional Gas Zones • Typically on 3-in-1 equipment, CTs are in

the same gas zone as the breaker • This requires additional equipment to be

taken out of service in order to de-gas the breaker

• Solution: ensure there is a buffer zone between the MOD and the CB

Design Considerations and Lessons Learned

Switches for Future Expansion • We originally included isolation switches to ease

future expansion • Due to the need to soak test the last piece of

connection bus and tie into interlocking in existing LCCs, the switches proved unnecessary

ORIGINAL INSTALL NEW INSTALL

Design Considerations and Lessons Learned

Bushing Zones • PPL requires gas/air bushings to be in

their own gas zone • Limits the extent of SF6 leakage in the

case of bushing failure or vandalism

Design Considerations and Lessons Learned

Universal Bid Documents • Spec covers all voltages. Variances noted in tables

– Similar to IEEE C37.122

• Scope template that is project specific • Price and spec sheet template that vendors fill out • Dedicated GIL Spec

Recent GIS Developments

Initial Cost Estimator Tool • Spreadsheet to help with high-level GIS estimates • Filled in with budgetary values from vendors

69/138kV 230kV 500kV Breaker Quantity/ Line Exits Cost

Breaker Quantity/ Line Exits Cost

Breaker Quantity/ Line Exits Cost

6 / 3 6 / 3 6 / 3 8 / 5 8 / 5 8 / 5 10 / 7 10 / 7 10 / 7 12 / 9 12 / 9 12 / 9 14 / 10 14 / 10 16 / 12 Building Size (Breaker Quantity) Cost

Dimensions (incl. line exits)

Building Size (Breaker Quantity) Cost

Dimensions (incl. line exits)

Building Size (Breaker Quantity) Cost

Dimensions (incl. line exits)

6 6 6 8 8 8 10 10 10 12 12 12 14 14 16

Recent GIS Developments (Cont.)

Lifecycle Cost Estimator Tool • Spreadsheet to help estimate maintenance costs • Filled in using maintenance cycles from vendors, as

well as PPL’s maintenance experience

GIS Maintenance Costs

Labor Rate/hr: $ 110.00

Discount Rate: 0.11

Number of breakers: 8

Number of disconnects per breaker 5

Category Item Frequency (yrs) Manhours Cost Notes Breaker Multiplier?

Disconnect Multiplier? Total Cost

Building and General Costs Crane Inspection 1 $ 900.00 OSHA requirement. Escorting third party inspector N N $ 900.00

Building and General Costs Air Handling System 1 16 $ 1,760.00

-Replace filters -Clean screens of dust and debris -Verify proper functionality of louvers -Verify functionality of fans/motors N N $ 1,760.00

Building and General Costs Camera System 1 1 $ 110.00

-Verify batteries charged and functional. -Verify camera is functional by spot checking several ports. N N $ 110.00

Building and General Costs Miscellaneous Indoor 1 8 $ 880.00

-Verify building heaters are functional -Check for sources of water intrusion, correct if possible. -Spot check trenways for signs of rodent infestation/damage. -Perform a test of fire detection system -Inspect GIS grounding conductors for signs of loose or damaged hardware. N N $ 880.00

Building and General Costs Miscellaneous Outdoor 5 1.5 $ 165.00

-Inspect grounding conductors for loose/damaged hardware -Review SF6 gauges for proper levels. Y N $ 1,320.00

Building and General Costs SF6 Quality checks 5 3 $ 330.00

-Dew Point -SF6 purity -SF6 monitor switching points Y N $ 2,640.00

ABB 500 Costs Breaker Mechanism Inspection/Service 5 24 $ 2,640.00

Check switching times, oil level, carbon brushes, possible leaks, electrical connections (standard breaker service) Y N $ 21,120.00

INPUT

$-

$10,000.00

$20,000.00

$30,000.00

$40,000.00

$50,000.00

$60,000.00

$70,000.00

$80,000.00

$90,000.00

$100,000.00

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40Year of Service

VENDOR 1 vs VENDOR 2 500kV

Vendor 2 Costs

Vendor 1 Costs

Building and General Costs

OUTPUT

Recent GIS Developments (Cont.)

Conceptual Planning with GIS • GIS previously used as a “Plan B” • Now evaluating GIS as a viable “Plan A” amongst

AIS alternatives • Spreadsheet takes into account total lifecycle costs,

as well as qualitative criteria

INPUT GLOBAL INPUTS: Discount Rate 0.11 Lifecycle (years) 40 OPTION 1 NAME OPTION 2 NAME

GIS AIS SPECIFIC INPUTS: Frequency (yrs) Cost Frequency (yrs) Cost Initial Cost $ 38,500,000.00 $ 37,500,000.00

Failure Cost Estimate 12 $ 200,000.00 4 $ 120,000.00

Maintenance Item 1 1 $ 10,000.00 1 $ 8,000.00 Maintenance Item 2 4 $ 12,000.00 4 $ 30,000.00 Maintenance Item 3 12 $ 30,000.00 8 $ 60,000.00 Maintenance Item 4 1 $ - 1 $ - Maintenance Item 5 1 $ - 1 $ -

Failure Net Present Cost $ 149,184.18 Failure Net Present Cost $ 268,531.52 Maintenance Net Present Cost $ 138,741.29

Maintenance Net Present Cost $ 205,874.17

Weight Value Rank Value Value Rank Value

Initial Cost 50.0% $ 38,500,000.00 0.487012987 $ 37,500,000.00 0.5

Net Present Lifecycle Cost 20.0% $ 287,925.47 0.20000000 $ 474,405.69 0.12138365 Security 5.0% Extremely Good 0.05 Very Good 0.041666667 Permitting 10.0% Good 0.066666667 Bad 0.033333333 Land Acquisition 0.0% Neutral 0 Neutral 0 Schedule 5.0% Good 0.033333333 Good 0.033333333 Safety 2.5% Extremely Good 0.025 Very Good 0.020833333 Ecological Impact 2.5% Good 0.016666667 Bad 0.008333333 Air Pollution Tolerance 0.5% Extremely Good 0.005 Good 0.003333333 Appearance/Aesthetics 1.0% Very Good 0.008333333 Good 0.006666667 Audible Noise 0.5% Very Good 0.004166667 Good 0.003333333 EMF 0.0% Extremely Good 0 Good 0 Disposal Concerns 3.0% Neutral 0.015 Very Good 0.025

100.0% RANK 0.911179654 RANK 0.797216981 Soft Considerations 0.224166667 0.175833333

OUTPUT

$-

$5,000,000.00

$10,000,000.00

$15,000,000.00

$20,000,000.00

$25,000,000.00

$30,000,000.00

$35,000,000.00

$40,000,000.00

$45,000,000.00

GIS AIS

Option Net Present Costs

Failure Net Present Cost

Maintenance Net Present Cost

Initial Cost

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

GIS AIS

Option Rankings

Soft Considerations

Net Present Lifecycle Cost

Initial Cost

Questions/Comments?

Nicholas Matone 2 North Ninth Street, GENN5 Allentown, PA 18101 Work: (610) 220-4403 Mobile: (570) 856-9922 E-mail: NMatone@pplweb.com