Georgia Transmission Corporation (GTC) Reliability Initiatives GSU Presentation September 2012

Douglas O. Maddox Manager – System Reliability Started as distribution & lighting engineer Manages a department of six engineers and coop student (1) Power Quality / Digital Fault Recorder (DFR) (2) Clearance Mitigation staff (1) Outage investigator (1) Benchmarking and results reporting (1) Trending and programs

GTC Background Created from Oglethorpe Power Corporation (OPC) reorganization in 1997 New smaller Board of Directors with outside directors Reliability is job one Keep improving until we say stop Continuous feedback on reliability Measure, report, and benchmark data Reduce frequency and duration of outages

This Presentation Illustrates how GTC reliability improvement is built upon the technology of remote sensing, monitoring, and control equipment Explains how GTC fits in to the overall utility structure in Georgia IS NOT about preventing widespread blackouts or new FERC/ NERC ERO standards

Functions and types of Georgia’s electric utilities Georgia UtilitiesFunction GenerationTransmissionDistribution Cooperatives - 39Oglethorpe Power Georgia Transmission Individual EMCs Municipals ~ 48MEAGPower Individual Cities Investor Owned - Georgia Power GPC Cooperatives - 3TVA

Georgia EMC Service Areas

Remote Sensing Equipment First generation of sensors was end-user notification – power problem or outage Equipment had no remote monitoring or control Relays were sensors but had no remote status or control Fuses and reclosers were down line sensors – no remote status Outage notification via postcard, letter, phone call, visit, etc. SCADA – supervisory control and data acquisition AMI – automated metering infrastructure Outage management systems - call in and tie to Geographic Information Systems (GIS) Facebook, twitter, web sites

Power Circuit Breakers Gas OilVacuum

Electromechanical Relays

Fuses (Southern States)

Recloser (Joslyn)

Meters Electromechanical Meter AMI Meter

SCADA RTUControl Panel

Remote sensors - continued Electronic relays and Digital Fault Recorders (DFRs) Fault indicators Fault Analysis and Lightning Location (FALLS) lightning data & weather data Phasor measurement units (PMUs) Line loading and monitoring Substation monitors Telecommunications 1.Phone lines 2.Satellite 3.Radio signals

DFR (USI)

SEL Relays SEL-551 SEL-351S SEL-587

PMU (SEL) SEL-351A (With PMU)

Line Loading Device (GridSense)

Substation Transformer Monitor (GridSense)

Fault Indicator (PDP)

FALLS Lightning Study Map

MAIFI One minute definition of sustained outage vs. momentary outage is < one minute Lightning normalized (Georgia Integrated Transmission System {ITS} standard) Found our ITS lines did not live up to stated Basic Insulation Level (BIL) levels of protection vs. stroke magnitude (older approach of 115 kV survives 30 kA strike) Electric Power Research Institute (EPRI) T- Flash program GTC standard 115 kV t/l design would have 3 momentary per year

Wins and Losses Results vary based on philosophy & location Great results Metal Oxide Varistors (MOVs) for Homeland –Macedonia Primary (3 per structure) from 8 to 100 kA flashed the line Terrible results for Douglas – Stump Creek (Black) – distribution pattern of did not work, nor does work Early fault indicator success – then false alarms Special 115 kV FI failed lab and field tests

T/L Arresters

Standard GTC 115 MOV approach Most structures are single poles Most structures have vertically mounted phases T-Flash predicts “O” outages per year with 3 MOV per pole T- Flash predicts 0.16 outages per year with 2 MOV per pole GTC generally will save one MOV per pole to stretch MOV funds Installation Pattern is top and bottom phase

Early Benchmarking 2003 trip to Florida Power and Light (FPL) for Georgia Power, GTC, and our control centers FPL = 4 min SAIDI GTC = 15 min SAIDI Differences Looped lines – two way feeds Redundant transformers Intelligent fault detection and location

Sustained Outage Programs GTC study found 75% of SAIDI is switching & restoring good loads; 25% is restoration Completed motorizing substation line switches Completed grounding switch replacements Nearly completed converting GTC’s pole mounted manually operated switches to remote control Extensive DFR upgrades, installations, & minis Replace obsolete switches Replace Silicon Carbide lightning arresters

Sustained Outage (continued) Split long circuits Modernize relaying (SEL) Replace older breakers Replace older transformers Add reliability criteria to alternative selection for capacity and voltage solving solutions Normally Open Point analysis Clearance mitigation efforts

Unfinished Sustained Outage Programs ITS grounding switches to be replaced Convert pole switches from manual to remote control One directional fault indicators to be installed Bidirectional fault indicators – testing phase Replacements for old technology arresters, first generation MOVs Replace older, obsolete switches On line transformer monitoring Carrier relaying, tuners, traps Real time DTF from DFR and SELs Supporting GPC (ITS) 46 kV enhancement program

Clearance Mitigation 2003 time frame 25% of SAIDI and SAIFI under abnormal conditions - clearances Both construction & maintenance Extended clearances Too many clearances Local equipment not in good condition

Clearance Mitigation (continued) Combine maintenance work with construction Combine line, sub, and metering work Combine ITS and EMC work Send report to EMCs daily Minimize abnormal time & mobile time Check lines and subs before going abnormal Contingency plans

Digital Fault Recorders (DFRs) Replaced old Rochester Brand Units New USI brand units are Sequence of Events (SOE) & DFR combination units, windows based, with data accumulator able to be connected to home office server New APP brand units initially bought for smaller subs and less capacity Allow GPC access to server & s Populate real time distance to fault data into SCADA Go beyond minimal federally required locations Tie DFRs to FALLS data server

Relay Data Server GTC hosted server similar to DFRs Allows access to relay data Cyber Security considerations Does send s

Power Quality Program Investigate transmission problems Assist EMC customers with investigations Temporary meters Permanent meters PQ data server – GTC and EMC access Consultant on standby AMI systems susceptible to PQ issues

Power Quality Meters TemporaryPermanent

MAIFI Improvements Overhead Ground Wire (OHGW) is installed on virtually all lines serving GTC loads Different workshops on lightning and grounding T/L MOVs FALLS acquisition ITS policy

FALLS Obtained our own subscription Review momentary outages down to 46 level Send reports to EMC Keep up with YTD results Keep up with MOV effectiveness Use in T-Flash Use for MOV pattern selection

Remote Sensor Issues Cost Reliability Ability to communicate Battery life Telecom path availability, capacity, and cost Ability to install and maintain on energized lines

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