DayCor® TechnologyTransmission

DayCor® Technology is used to detect Corona Particle Discharge and Arcing

on electric grid components.

It offers you:

• Early warnings of potential future failures.• Pinpointing & Visualizing the corona effect. • Decision ability to determines the health of your critical systems components• Prioritize your particle discharge maintenance challenges • Day time work DayCor® Technology saves you by avoiding costly unscheduled outages and failures

DayCorDayCor®® Technology Technology

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UV Ph

UV Ph

UV Ph

Corona is a luminous partial discharge due air ionization. The DayCor® camera pinpoints the exact source’s location by visualizing the UV photons, coming out of it.

Corona EffectCorona Effect

Corona Source Free Electron, coming out from the source

Natural Air molecule

UV Photon

Combined mode

Visible only display

UV only mode

Bi-Spectral ImagingBi-Spectral Imaging

Pinpointing the exact corona’s location

UV-IR complimentary technologiesUV-IR complimentary technologies

No corona on IR picture Corona spots using UV technology

Live End Corona

Dead End Corona

It causes:• Degradation of polymer (NCI) insulators• Ceramic Insulator Defects • Physical damage to component.• Cracks the cement of pins and metal caps of porcelain

insulators.• Audio noise (AN)

Corona is a concern because:Corona is a concern because:

Degradation of polymer (NCI) insulatorsDegradation of polymer (NCI) insulators

To get to that point is to waste your time & moneyDetect this failure in advance to take the right action on time

Corona Spot The outcome

Ceramic insulators defects Ceramic insulators defects

Component: 138 kV Insulator StringProblem: First Insulator bell is damaged

Physical damaged to componentPhysical damaged to component

Left string- Outcome Right string - Outcome

Corona spots

Crack in cement and metal caps of porcelain insulatorsCrack in cement and metal caps of porcelain insulators

Corona Spot Outcome

Audio noise - few reasonsAudio noise - few reasons

• Component: Connector on 138 kV Transformer Bushing• Problem: Sharp edges on connector cause radio and TV

interference

Audio noise - few reasonsAudio noise - few reasons

It indicates:• Possible Faults• Sealing defects• Shorted bells• Gap discharge • Loose hardware• Contamination• Corrosion or erosion• Broken Strands• Bad ground connections

Corona is a concern because:Corona is a concern because:

Possible FaultsPossible Faults

Corona on the connection between the bushing and the capacitor.

Losing Energy it to lose Money !

138Kv

Possible FaultsPossible Faults

Leaking Current

Dead End Corona

Sealing DefectsSealing Defects

Indication The problem

Hollow core insulator. The core should be sealed at the bottom with a cork/rubberplug. The cork/rubber plug was cracked compromising the seal. Without the seal, moist air was introduced into the hollow core. The dielectric properties of the insulator were changed affecting the electric field.The condition would eventually lead to insulator failure.

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Sealing DefectsSealing Defects

Shorted BellsShorted Bells

When you see corona at the middle of the insulator and the rest of it is clean check for short bells case

Pic 1: Corona on the 4th bell.

Pic 2: Porcelain bells were replaced by glass bells due to being shorted

1

2

Gap DischargeGap Discharge

Loose hardwareLoose hardware

ContaminationContaminationagricultural pollutionSalt contamination Agricultural pollution

Polluted conductor

Corrosion or ErosionCorrosion or Erosion

Corona spot due to erosion

Broken StrandsBroken Strands

Bad ground connectionsBad ground connections

AN, RI, TVI concern?

Decision ChartDecision Chart

Photons per Minute Can it

be damaged by corona?

Corona- where?

Criticalcomponent?

Material typeCritical location?

Corona intensity?

No

No

No

Yes

Yes

Yes

High> 5000

1000<Medium<5000 Low<1000

Monitor for additional signs

Schedule repair or replacement

Repair or replace ASAP

No

Yes

Repair or replace ASAP

Condition

D

Equipment fails to perform as expected

Functionally failed

High CountingRate

Equipmentbroken

Outage

Potential Failure

C

Medium Counting Rate

Failure ProcessFailure Process

Failure starts here

LowCounting Rate

B

Equipment atNormal conditions

NoCorona

A