Practices, Intervals, and Asset Management for Substation Equipment - - PowerPoint PPT Presentation

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Practices, Intervals, and Asset Management for Substation Equipment - - PowerPoint PPT Presentation

Dec 31, 2022 175 likes •684 views

Maintenance Best Practices, Intervals, and Asset Management for Substation Equipment Presented by: Paul Schlies, President Energis Holdings, LLC Background - 40 Years in the Industry Education NWTC (Northeast WI Technical College)

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SLIDE 1

Maintenance Best Practices, Intervals, and Asset Management for Substation Equipment

Presented by: Paul Schlies, President Energis Holdings, LLC

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SLIDE 2

Background - 40 Years in the Industry

  • Education
  • NWTC (Northeast WI Technical College)
  • Work History
  • Wisconsin Public Service (WPS) – 24 years
  • American Transmission Company (ATC) – 6 years
  • Energis Holdings, LLC – 13 years
  • Formerly known as Energis High Voltage Resources, Inc.
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SLIDE 3

Not One Right Way

  • There is not only one answer to a perfect Substation Maintenance
  • Schedule. Today we’ll be using our industry and utility

experience, but your engineering firm, the manufacturer’s equipment specifications, insurance requirements, and NETA Standards should also be considered.

  • Along with our recommendations, we’ve included survey results
  • f maintenance schedules from individuals within the electrical
  • utility. The information is included in the handout for your

review, but because of today’s time limitations we will not discuss.

  • Electronic copies of this presentation are available.
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SLIDE 4
  • Safety
  • Public
  • Employees
  • Improve Reliability
  • Reduce customer outages
  • Reduce Costs
  • Reduce unplanned maintenance cost
  • Reduce insurance/liability cost
  • Plan and Budget Asset Upgrades
  • Bulk Electric Assets, NERC Compliance

Why Perform Substation Equipment Testing and Maintenance?

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SLIDE 5

Transformer Testing

  • Power Factor
  • Ratio
  • Insulation
  • Winding Resistance
  • SFRA (Sweep Frequency

Response Analysis)

  • DGA and Oil Quality
  • Arresters
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SLIDE 6

Transformer Maintenance

  • Verify oil level in main tank & LTC
  • Verify oil level in bushings
  • Verify insulator integrity
  • Verify tank integrity and free of oil leaks
  • Inspect surge arresters
  • Verify paint is in good condition
  • Record winding/liquid temperatures (current &

max)

  • Record LTC position indicator & operation counter

(current & max raise/lower)

  • Verify correct operation of fans and free of bird

nests

  • Verify correct operation pumps (if applicable)
  • Verify nitrogen pressure (if applicable)
  • Verify transformer and pad are level
  • Verify control cabinet is free of moisture
  • Verify cabinet heater operation

Frequency

  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
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SLIDE 7

Transformer Maintenance

  • Thermographic imaging (Infrared)
  • Transformer oil analysis (DGA and Oil Quality)
  • Power factor test
  • Winding resistance test
  • Transformer turns ratio test
  • Insulation test
  • Arresters
  • Calibrate temperature gauges
  • Verify alarm points
  • Verify Buchholz relay operation
  • Verify rapid pressure rise relay operation
  • SFRA (Sweep Frequency Response Analysis)
  • Vibration & acoustic testing
  • LTC Internal Inspection

Frequency

  • Annual
  • Annual
  • Every 5 years
  • Every 5 years
  • Every 5 years
  • Every 5 years
  • Every 5 years
  • Every 5 years
  • Every 5 years
  • Every 5 years
  • Every 5 years
  • New install & after fault operation
  • Dependent on criticality of equipment
  • Every 5-10 Years
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SLIDE 8

Industry Survey Results Transformers

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SLIDE 9

Industry Survey Results Transformers

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SLIDE 10

Industry Survey Results LTC

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SLIDE 11
  • Power Factor ( 345kV)
  • Timing and Motion
  • Micro-ohm
  • Ratio Bushing Current

Transformer (New, Suspect, Relocated)

  • SF6 Gas

Circuit Breaker Testing

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SLIDE 12

Circuit Breaker Maintenance

  • Verify breaker is level
  • Verify paint is in good condition
  • Verify insulator integrity
  • Verify SF6 gas pressure (check oil level in oil

breaker)

  • Record operation counter number
  • Verify control cabinet is free of moisture and

cabinet is working

  • Check control voltages & operation of breaker
  • Thermographic imaging (Infrared)
  • Verify tank heaters (if applicable)
  • Motion testing (speed test)
  • Micro-ohm (ductor) contacts
  • Test SF6 gas for moisture, purity & SO2 content
  • Check alarm points in control house

Frequency

  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Annual
  • Annual
  • Annual
  • Every 5 years
  • Every 5 years
  • Every 5 years
  • Every 5 years
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SLIDE 13

Industry Survey Results Circuit Breakers

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SLIDE 14

Industry Survey Results Circuit Breakers

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SLIDE 15

Industry Survey Results Circuit Breakers

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SLIDE 16

Industry Survey Results Circuit Breakers

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SLIDE 17
  • Thermographic Imaging

(Infrared)

  • Insulation Resistance Test
  • Micro-ohm Contact Resistance
  • Hi-pot Vacuum Bottles

Distribution Breaker Testing

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SLIDE 18

Distribution Breaker Maintenance

  • Verify insulator integrity
  • Verify control cabinet is free of moisture
  • Verify cabinet heater operation
  • Record operation counter number
  • Thermographic imaging (Infrared)
  • Insulation resistance test
  • Micro-ohm (ductor) contacts
  • Hi-pot vacuum bottles
  • Hi-pot oil

Frequency

  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Annually
  • Every 5 years
  • Every 5 years
  • Every 5 years
  • Every 5 years
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SLIDE 19
  • Perform as found test
  • Perform as left test
  • Test relays to installed setting
  • Trip test relays

Relay Testing

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SLIDE 20

Relay Maintenance

  • Check relays for damage
  • Record targets found and reset
  • As found test
  • As left test
  • Trip test relays
  • Programmable relays
  • Mechanical relays

Frequency

  • Monthly
  • Monthly
  • 5-10 years
  • 5-10 years
  • 5-10 years
  • 5-10 years
  • Varies depending on environment
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SLIDE 21
  • Maintenance usually based on

manufacturer’s recommended

  • perations and load.
  • DGA Oil Analysis
  • Frequency - Annual or Bi-annual

Voltage Regulator Testing

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SLIDE 22
  • Disconnects
  • Micro-ohm
  • Insulation Test
  • Verify Mechanical Operation
  • Verify Electrical Operation (if

applicable)

  • Frequency for All – Every 5

years

  • Surge Arrester
  • Check for arcs and burns
  • Check electrical connections

Disconnects & Surge Arrester

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SLIDE 23
  • Perform Monthly Inspections
  • Check for targets
  • Check insulators for cracks
  • Check blade is closed properly
  • Check heater in MOD is working
  • Check for moisture in MOD
  • Perform Yearly Inspections
  • Perform 5 Year Maintenance

Circuit Switcher

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SLIDE 24
  • Specific Gravity
  • Cell Strap Connection

Resistance

  • Internal Cell Resistance
  • Voltage Readings

Battery & Charger Testing

Flooded Cell Nickel kel Cadmium

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SLIDE 25

Batteries & Charger Maintenance

  • Visual inspection of electrolyte levels
  • Visual inspection of battery jars
  • Verify no battery grounds exist
  • Record battery voltage & current
  • Specific gravity
  • Intercell impedance/resistance
  • Strap resistance
  • Individual cell voltages/total cell voltage
  • Equalize voltages
  • Verify charger alarms
  • Check voltage ripple

Frequency

  • Monthly
  • Monthly
  • Monthly
  • Monthly
  • Annual
  • Annual
  • Annual
  • Annual
  • Dependent on battery test results
  • Annual
  • Annual
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SLIDE 26

Industry Survey Results Batteries

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SLIDE 27

Questions to Think About

  • How do you document the performed maintenance & testing

results?

  • What type of test forms do you have?
  • Where do you have this information at your facility?
  • What are good utility practices?
  • What are the reasons for documentation of all testing and

maintenance work performed?

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SLIDE 28
  • What fits your company needs?
  • How big is your system
  • What are you going to want to track
  • Computerized system
  • Spreadsheet type system
  • What can it do?
  • Name plate information by substation
  • Inspection reports
  • Maintenance reports
  • Maintenance schedules
  • Build annual budgets
  • Justify asset replacement
  • Levelize maintenance cost

Asset Management

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SLIDE 29

Reminder to all!

Preventative Maintenance Plan Report (5-GF-113) PSC 113.0607(2)(b)6. Is due on or before May 1 (odd numbered years)

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SLIDE 30

Failures and Their Cause

“The why we do maintenance”

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SLIDE 31

SF6 Breaker Leak (Video)

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SLIDE 32

SF6 Breaker Leak Cont.

  • Cause: Age, lack of

maintenance

  • Fault: None, SF6 moisture

greater than 4x manufacture acceptable limits

  • Damage:
  • Corrosion on sealing surface

was so severe

  • bushing top needed to be sent
  • ff to be machined
  • Increasing outage time.
  • Post Failure Assessment:

SF6 leak was neglected for years, gas was added on regular basis by multiple un- qualified personal which ultimately led to increase in moisture and soon to be certain, fault.

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SLIDE 33

Feeder Breaker

  • Cause: Animal
  • Fault: Started phase to phase, went

phase to ground.

  • Post Failure Assessment:
  • Relay was not tested after new

settings were uploaded.

  • Five (5) year maintenance was

not performed on the relay.

  • Relay never saw the fault
  • System operations opened up

down stream breakers

  • Damage: Feeder breaker, Power

transformer, Station transformer, Underground cable, Arresters, Oil circuit breaker, Bus work, Bus PT’s, Disconnects and Steel structure.

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SLIDE 34

Heating Connection

  • Cause: Dirty connection
  • Fault: None, excessive

heating

  • Post Failure Assessment:
  • Terminations were not

cleaned during assembly

  • annual infrared scanning

was not performed

  • Damage: Aluminum

conductor and breaker bushing top

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SLIDE 35

GSU Transformer

  • Cause: Internal failure
  • Fault: Started phase to

phase, went phase to ground

  • Post Failure Assessment:
  • Transformer was tested 7

years prior to faul

  • DGA showed signs of gas

increase

  • Damage: 345kV GSU

Transformer, Lost generation time

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SLIDE 36

GSU Transformer Cont.

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SLIDE 37

GSU Transformer Cont.

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SLIDE 38

Load Tap Changer

  • Cause: Moisture
  • Fault: None
  • Post Maintenance

Assessment:

  • Tap changer compartment was

not entered for 12+ years

  • Desiccant dryer was not

maintained yearly or as needed

  • Damage: All contacts, liquid

level gauge, compartment is rusting

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SLIDE 39

Load Tap Changer Cont.

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SLIDE 40

Load Tap Changer Cont.

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SLIDE 41

Load Tap Changer Cont.

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SLIDE 42

Load Tap Changer

  • Cause: Loose

Connection

  • Fault: Reversing Lead

Failure

  • Post Maintenance

Assessment: Reversing lead connection was loose with coking present

  • Damage: New barrier

board and reversing lead needed to be installed

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SLIDE 43

CT Termination Block

  • Cause: Possible

Overheating/arcing between CT Terminals

  • Fault: CT block
  • Damage: New CT termination

block was installed.

  • Post Maintenance

Assessment: Customer reported N2 leak, Leak was identified as damaged CT termination block. Monthly inspections identified N2 leak, investigation found leak before moisture egress compromised transformer winding integrity.

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SLIDE 44

GCB Anti- Pump Relay

  • Cause: Breaker anti-pump

inoperable due to incorrect wiring

  • Fault: None
  • Damage: None
  • Post Maintenance Assessment:

Upgrade performed between maintenance cycles, incorrect wiring rendered anti-pump circuit inoperable until caught during maintenance testing, luckily no faults occurred on system to initiate a breaker reclose between maintenance cycles

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SLIDE 45

Bushing Damage

  • Cause: Animal
  • Fault: Phase to Phase
  • Damage: Small arc from animal

damaged bushing seal.

  • Post Maintenance

Assessment: Damage would not have shown up in immediate insulation tests. Loss of seal was not verified until bushing was removed and tipped resulting in

  • il loss.
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SLIDE 46

Termination Failure

  • Cause: 600A pass-through

bushing failure

  • Fault: None
  • Post Maintenance

Assessment: Termination failed during TD testing. Deviation was identidfied on voltage steps.

  • Damage: None, failing

termination was identified during maintenance testing, repaired with no lost time.

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SLIDE 47

Switch Drive Pipe

  • Cause: 34.5 KV switch Installed

by un-qualified personal

  • Fault: None
  • Damage: None
  • Post Maintenance

Assessment: Clearance issue was identified during 1st evolution of 5 year maintenance

  • cycle. Clearance from end of

drive pipe to adjacent switch live parts: < 8.0”. Switches had never been open during normal

  • peration.
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SLIDE 48

Testing to NETA Specifications

  • NETA is an organization that

serves the electrical testing industry by offering accreditations of 3rd party electrical testing firms, certifying electrical testing technicians and producing American National Standards.

  • Free download available:
  • Appendix B – Frequency of

Maintenance Test

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SLIDE 49

Thank you for your time and attention.

  • Talk to Ben, Brad, Chris, Derek, Paul or any Energis Representative
  • Ben Swanson· bswanson@energisinc.com· 920.883.6947
  • Brad Beyer· bbeyer@energisinc.com· 920.655.1102
  • Chris Warden· cwarden@energisinc.com· 920.883.6893
  • Derek Drewiske· ddrewiske@energisinc.com· 920.327.8621
  • Paul Schlies· pschlies@energisinc.com· 920.639.8688

QUESTIONS?