Improving electrical system reliability
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Improving Electrical System Reliability. Blackout News Headlines. Situation Analysis. Fact # 1: The aggregate economic loss of electrical power disruptions has climbed to more than $100 billion per year or more than 1% of U.S. Gross Domestic Product!

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Situation analysis l.jpg
Situation Analysis

  • Fact # 1: The aggregate economic loss of electrical power disruptions has climbed to more than $100 billion per year or more than 1% of U.S. Gross Domestic Product!

    • Recent events have demonstrated the fragility of our aging power grid. With transmission networks operating close to their stability limits, minor faults can cause cascading outages. Capacity limitations in several regions can lead to economic losses that cascade through the economy, causing loses for not only residential, but also commercial and industrial institutions.


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Situation Analysis (Page 2)

  • Fact # 2: The recent power outages have been in the works for the last several years!

    • U.S utilities have always taken pride in their uptime and system performance. Over the past several years, due to industry-wide deregulation, market pressures for rate reductions, business restructuring and downsizing, overall investment in infrastructure has not been at traditional levels. The decoupling of transmission, distribution and generation has caused disruption in traditional business models and industry workings (i.e. the vertically integrated utility no longer exists in deregulated markets)


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Situational Analysis (Page 3)

  • Fact # 3: De-regulation has contributed to loss of stability.

    • When the Federal Energy Regulatory Commission dictated that the electrical transmission network was to be opened to the free market, it allowed anyone to transmit power over any transmission line. This allowed generators outside a customer’s service area to bid on a distant customer’s power requirements and be guaranteed access to that customer over the transmission system. As a result, the owners of the transmission lines lost some of their ability to maintain stability since these lines now carry power generated outside their control. As demand has continued to increase at an average 2% per year and because few will accept new transmission lines in their backyard, grid stability continues to degrade over time.


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Situational Analysis (Page 4)

  • Fact # 4: The 2000 dotcom implosion and the resultant relaxation of electrical demand has temporarily relaxed the demands placed on electrical transmission system, but the problem remains.

    • The recent retraction of the economy has reduced electrical demand temporarily. However little or no new transmission has been constructed during this economic downturn. When electrical demand returns to historic levels, we can only expect the problem to return and even become worse as the economy expands to more robust levels.


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Conclusion

  • This problem will worsen before it improves

  • Companies must take action themselves


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What Can Be Done?

  • Protect Yourself From External Problems

    • Install Local Backup Power

      • Eaton/CAT Solutions

        • Natural Gas, LPG, Diesel from 18 kW to 2000+ MW

    • Install Voltage Correction

      • Eaton SAG Correction Equipment

      • Eaton Supplied UPS

      • Eaton Capacitors

    • Cutler-Hammer Engineering Services and Systems (CHESS)

      • Audits

      • Site Supervision,

      • Equipment Commissioning

      • Turnkey Installation


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Is The Utility Always To Blame?

  • Most plant outages are not caused by loss of utility power, but rather by internal problems

  • Protect yourself from internal problems

    • Equipment failure, accelerated by:

      • Dust, dirt, moisture, rodents, etc.

      • Thermal cycling, vibration induced loosening, etc.

      • Obstruction of ventilation, etc.

      • Operator error

      • Reduction in funding for preventative maintenance

  • But when resources are tight, where should they be spent to give maximum uptime?


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What Can Be Done?

  • Protect Yourself From Internal Problems

    • Cutler-Hammer Engineering Services and Systems (CHESS)

      • Coordination Study

      • Harmonics Study

      • Site Survey (e.g. evaluation of on-site generation, UPS, calculation of reliability of existing system, etc.)

      • Thermography

    • Predictive Diagnostics

      • Early warning of pending failure in MV Equipment


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Where Do I Start?

1. Establish Current Condition of Facility

2. Determine Likelihood of Serious Problem Based on this Condition

3. Sort to Find Equipment Most at Risk to Cause Problems

4. Identify the Predictive Techniques that Gives Early Warning of Problems at that Equipment


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Internal Problems are Ticking Time Bombs…

  • The ‘Quiet Crisis’Term created by Paul Hubbel, Deputy Director, Facilities and Services, Marine Corps. Government Executive Magazine, Sept 2002.When he was asked “why isn’t preventative maintenance adhered to more closely in government facilities?”“We call it the ‘quiet crisis’ because a lot of maintenance problems take time to occur and are not noticed until damage occurs”.


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Your Facility?

  • Okay, so maybe some think they may be more reactive than proactive…but what about you?

  • What happens if thepower goes out at yourfacility for an extendedperiod of time?For example, we would expect thatcritical facilities (such as prisons) won’t have power outage problems!


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Maximum Security Prison

  • WASCO State Prison, California Department of Corrections “Wasco suffered an electrical failure in April 1999 that caused a total power outage lasting almost seven hours-a problem that Wasco could have prevented had management made certain that staff repaired previously identified flaws in the electrical system.”California State Auditor/Bureau of State Audits Summary of Report Number 99118 - October 1999


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Municipal Detention Center

  • Yolo County Sheriff’s DetentionFacility, California On Tuesday, July 9th 2002, the Sheriff’s Department experienced a power outage. Normally, this is not a major problem as our backup generator provides electrical power in the event of an outage. However, this was not the case on July 9th, and the detention facilities did not have electrical power for four hours.”http://www.yolocountysheriff.com/myweb5/Sheriff%20Final/2002%20Commendation%20Awards/Tina%20Day.pdf


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State Penitentiary

  • Riverside Correctional Facility, Michigan“…however, in April 1998, RCF lost its main power source and the emergency generator failed to start. This resulted in an emergency situation for RCF.” Performance Audit, Michigan Department of Corrections, Feb 1999


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Why is Maintenance Skipped?

  • Clearly there are problems, but why?

  • Budget Cuts / Management Redirection of Maintenance Funds

  • This results in “Crisis Mode Operation” or “Fix What’s Broke and Skip the Rest” mentality

  • But how do you guess what will break next and where money should be targeted?

  • Is there an analytical way of targeting scarce resources?


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Step 1

1. Establish Current Condition of Facility

2. Determine Likelihood of Serious Problem Based on this Condition

3. Sort to Find Equipment Most at Risk to Cause Problems

4. Identify the Predictive Techniques that Gives Early Warning of Problems at that Equipment


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Internal Problem Locator

52

52

52

52

52

  • What is the likelihood of a loss of MV power at either the Administration Building or at Health Services?

  • Answer:f(SW1) + f(CBL1)+ f(TX1)+ f(CBL2) + f(BKR1)+ f(RLY1)+ f(BUS1) + f(BKR2)+ f(RLY2)+ f(BKR5) + f(RLY5) + f(CBL6)- f(…) means hours/year failure rate

SW1

CBL1

TX1

CBL2

BKR1

RLY1

51

BUS1

BKR2

BKR3

BKR4

BKR5

51

51

51

51

RLY2

RLY3

RLY4

RLY5

CBL3

CBL4

CBL5

CBL6

Admin

Housing

Unit 1

Housing

Unit 2

Health

Services


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Failure Time / Year

  • Failures / Year

    • How often failures occur

    • Mean Time Between Failures

  • Duration (hrs) / Failure

    • How long it takes to repair a failure


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Step 2

1. Establish Current Condition of Facility

2. Determine Likelihood of Serious Problem Based on this Condition

3. Sort to Find Equipment Most at Risk to Cause Problems

4. Identify the Predictive Techniques that Gives Early Warning of Problems at that Equipment


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IEEE 493-1997 (Gold Book) Analysis

IEEE Std 493-1997, Table 7-1

Failures/yr * Hours/Failure = Hours/Yr

* when no on-site spare is available ** below ground *** 3 connected to 3 breakers


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Switchgear Failure Scenario

52

52

52

51

51

51

f(SW1) + f(CBL1)+ f(TX1)+ f(CBL2) + f(BKR1)+ f(RLY1)+ f(BUS1) + f(BKR2)+ f(RLY2)+ f(BKR5) + f(RLY5) + f(CBL6)

  • 1 incoming disconnect switch (.022 hrs/yr)

  • 300’ incoming MV cable (300/1000 * 0.1624 = 0.049 hrs/yr)

  • 1 incoming transformer (1.026 hrs/yr)

  • 100’ cable (TX to gear) (100/1000 * 0.1624 =0.0162 hrs/yr)

  • 1 MV bus run with 3 MV breakers (.2733 + 3(.2992)=1.1709 hrs/yr)

  • 3 protective relays (3*.001 = 0.003)

  • 300’ outbound MV cable (300/1000 * 0.1624 =0.049 hrs/yr)

  • Total = 0.022 + 0.049 + 1.026 + 0.0162 + 1.1709 hrs/yr + 0.003 + 0.049 = 2.33 hrs/yr (average)

?% uptime

8757.67 = 99.97%

8760 – 2.33


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Equipment Failure Timing

  • Initial failures (installation problems, infant mortality of installed components).

  • Degradation over time (temperature, corrosion, dirt, surge)

Initial

Failures

Degradation

Failures

Likelihood

Of

Failure

Area under hatch marks represents the total likelihood of a failure

2.33 hrs/yr

(average)

Time


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Equipment Failure Timing

  • Poor maintenance reduces equipment life since failures due to degradation come prematurely soon. IEEE says add 10% to likelihood of downtime.

Initial

Failures

Early

Degradation

Failures

Likelihood of failure is higher because postponed maintenance increases problems due to corrosion, misalignment, etc, that would be picked up in a PM program

Likelihood

Of

Failure

2.59 hrs/yr

(average)

Time


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Results

  • Fair Maintenance = 2.59 hrs/year downtime

  • Good Maintenance = 2.33 hrs/year downtime

  • 2.59 – 2.33 = 0.26 hr/yr less downtime

  • 16 minutes per year more downtimeIs that worth spending any time fixing?

    … but this is only a simple example


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Real Systems Are Much Larger

  • 17 MV breakers

  • 14 MV loop feed switches

    • 3 switching elements

    • 42 total

  • 31 MV internal bus runs

    • (17+14)

  • 4000’ MV cable

  • 15 MV transformers

  • 3 standby generators

Typical Large MV System


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LV System Are Very Complex Too…

  • 13 switchboards containing:

    • 155 LV breakers

  • 105 panelboards containing:

    • Over 2000 panelboard breakers

  • 1000’s of cable terminations

  • 30000 feet of cable

Partial Diagram of Large LV System


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What is the likelihood of a power failure at this location?

Just looking at a portion of the equipment…

  • 42 MV disconnect switches (42 * .022 = 0.924 hrs/yr)

  • 4000’ MV cable (4000/1000 * 0.1624 = 0.649 hrs/yr)

  • 15 MV transformers (15.39 hrs/yr)

  • 30000’ LV cable (30000/1000 * 0.0148 = 0.444 hrs/yr)

  • 31 MV bus run with 17 MV breakers (31(0.2733) + 17(.2992)= 8.47 + 17.23 = 25.77 hrs/yr)

  • 17 protective relays (17*.001 = 0.017)

  • Total = 0.924 + 0.649 + 15.39 + 0.444 + 25.77 + 0.017 = 43.19 hrs/yr (average)(Assuming a 1 hr/per failure means you would expect an electrical problem 43 times per year or almost 1 per week!)


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Step 3

1. Establish Current Condition of Facility

2. Determine Likelihood of Serious Problem Based on this Condition

3. Sort to Find Equipment Most at Risk to Cause Problems

4. Identify the Predictive Techniques that Gives Early Warning of Problems at that Equipment



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Step 4

1. Establish Current Condition of Facility

2. Determine Likelihood of Serious Problem Based on this Condition

3. Sort to Find Equipment Most at Risk to Cause Problems

4. Identify the Predictive Techniques that Gives Early Warning of Problems at that Equipment


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Now What?

  • We now know how to figure “how many minutes of outage will occur each year” for each device.

  • But how do we reduce that value?

  • We can recognize that failures can be predicted if we recognize the early warning signs

    • The so-called “Predictive Indicator”

  • Once we know that, we can identify the likely cause and fix the problem before it is serious.


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Predicting Failures

Failure Contributing Causes

Leads to …

Initiating Causes

Leads to …

Predictive Indicator


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Failure Contributing Causes (Source:IEEE 493-1997)



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Initiating Causes Predictive Indicators


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Available Predictive Tools

CBM – Condition Based Maintenance

  • Top 4 in order of importance are:

  • - Partial Discharge Diagnostics (22.4%)- Visual Inspection (18.1%)- On-Line Thermal Analyzer (15.6%)- Thermographic Inspections (12.0%)


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What If We ImplementedOne Predictive Solution?

  • Partial Discharge – 22.4% of failures detected

    • Caveat: Only works on medium voltage (>1000 volts)

  • Our example:

    • 15.39 hrs/yr from transformer failure

      • 22.4% reduction  11.94 hrs/yr

    • 8.47 hrs/yr from MV bus failure

      • 22.4% reduction  6.57 hrs/yr

    • 17.23 hrs/yr from MV breaker failure

      • 22.4% reduction  13.37 hrs/yr


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Reduction In Outages

  • Transformer Failure (was 15.39 hrs/yr, now 11.94 hrs/yr)

    • Saving 3.45 hrs/yr

  • MV bus failure (was 8.47 hrs/yr, now 6.57 hrs/yr)

    • Saving 1.9 hrs/yr

  • MV breaker failure (was 17.23 hrs/yr, now 13.37 hrs/yr)

    • Saving 3.86 hrs/yr

  • Total Savings from PD9.21 hrs/yr

    • 1 hr/failure = 9 fewer failures?

    • 10 hr/failure = 1 fewer failure?

    • So what is the correctanswer?

Failures/yr

Hrs/failure


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Determining Number of Failures

Start by capturing the hrs/failure and hours/yr for each device

* when no on-site spare is available ** below ground *** 3 connected to 3 breakers


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Average Outage

Next, total the number of devices and determine the total hours of failure for each device and for all devices

Divide the total by the number of devices.

Result = Average hours per failure


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Compute Likely FailureRate

  • Total Savings from PD9.21 hrs/yr

    • 1 hr/failure = 9 fewer failures per year

    • 10 hr/failure = 1 fewer failure per year

    • 25.4 hr/failure = 0.36 fewer failures per year

      • Answer: 1 fewer failure every 3 years

0.36 failures/

year

25.4 hrs/

failure


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How Much Does It Cost?

  • We know that if we install PD sensors on all this equipment, statistically it will result in 1 less outage every three years.

  • Each PD sensor costs ~ $7000 installed

  • We have 92 items to be monitored

  • $7000 * 92 = $644000

  • Does saving an outage once every 3 years justify spending $644000?


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Cost Savings Through Reduced Outage (Detected by PD)

Total Exposure = Median Outage duration * % Related to Insulation * Downtime Cost


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Your Mileage May Vary…

Using this $10000 assumption…

  • At $10,000 / hour of downtime costs

    • Loss of one of the small power transformers would cost:

      • $537000 of downtime ($240,000 / day)

    • Cost of a 1000 kVA indoor dry, MV power transformer

      • Assume $18/kVA or $18000

      • Assume labor $50/hr, 3 man-days labor

      • Total cost = (1000 * $18) + ($50 * 3 * 8) = $18000 + $1200Total cost = $19200

    • Downtime and material = $537000 + $19200Downtime and material = $556200


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Compute Payback

  • Our cost is $644000

  • Our savings is $556200 once every 3 years or $185400 per year

  • Assume we expect a 10% return on invested capital

  • Assume 10 year project life

  • Assume 2.5% inflation rate


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Compute Equivalent Payback

  • Cost = $644K, Savings = $185.4/yr, N=10 years, inflation = 2.5%, capital cost = 10%

  • Is this a good investment?

  • Simple Payback = $644K/$185.4K = 3.47 years(10-3.47)*$185.4 - $644K = = $567K positive cash flow (life of project)

  • Does this cover cost of capital (10%) considering the reduction in value of money over time (2.5% inflation)?


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Compounded IRRCalculator

Cost installed cost of equipment

Savings annual savings

a (1+g)/(1+i)

i interest rate

g annual inflation rate

n duration (payback period in years)


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Compounded IRRCalculator

Cost $644,000

Savings $185,400

a (1+g)/(1+i) = (1+0.025)/(1+0.1) = 0.932

i 10%

g 2.5%

n 10


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Run The Numbers…

Cost $644,000

Savings $185,400

a (1+g)/(1+i) = (1+0.025)/(1+0.1) = 0.932

i 10%

g 2.5%

n 10



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What Does 9.6 Mean?

  • Based on a cost of $644K, an annual savings of $185.4K, a required rate of return of 10%, and inflation rate of 2.5%…

    • 9.6 means a payback is achieved in 9.6 years

    • means that the payback is under 10 years

  • Since our project life is 10 years

    …this project is financially viable.

    Said another way:

  • If you put $644K into this investment, it will return 10% per year every year for 10 years plus enough additional cash to completely pay for the $644K initial investment.


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Great, I’ve Found Problems, NowWhat?

  • You can certainly replace with newor…

  • If you catch it before it fails catastrophically, you can rebuild

  • Many old electrical devices can be rebuilt to like new condition


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LV Refurbished Power Breakers

510- Upgraded Trip

610- Display

810-KW-Comm-O/C

910-Harmonics

  • LV Equipment Retrofit / “Roll-In” Replacements

- (W) - C-H

- ITE - GE

- AC - FPE

- Siem - R-S


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LV Rack-In Replacement With New (In Old Equipment)

  • Old Breaker:

  • Parts no longer available

  • Modern Breaker:

  • New warranty

  • Installed in the old structure


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Motor Control Upgrades

Breaker-to-Starter Conversions:- circuit breaker used to start motor- only good for 1000 or less operations- replace breaker with starter- now good for 1,000,000 operations

Continuous Partial Discharge Monitor

MCC Bucket Retrofits- new breaker and starter


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MV Vacuum Replacement

  • Vacuum replacement for Air Break in same space

  • Extensive Product Availability

    • ANSI Qualified Designs

    • 158 Designs

  • Non-Sliding Current Transfer

  • SURE CLOSE - Patented (MOC Switches)

  • 2-Year Warranty - Dedicated Service

  • Factory Trained Commissioning Engineers

  • Full Design & Production Certification

  • ANSI C37.59 Conversion Standard

  • ANSI C37.09 Breaker Standard

  • ANSI C37.20 Switchgear Standard

  • Design Test Certificate Available on Request


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Can’t Buy a Spare? Class 1 Recondition Instead

  • Receiving & Testing

  • Complete Disassembly

  • Detailed Inspection and Cleaning

  • New Parts

  • OEM Re-assembly

  • Testing

  • Data-Base Tracking


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Spot Network Upgrade

Network Protector Class 1 Recondition

Network Relay Upgrades...


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Transformer Oil Processing

On-Board Testing

Dielectric Testing

Karl Fischer Moisture Test

Acid Titration Testing

  • Other Services Available:

  • Samples Obtained On-Site

  • Mail-in Sampling Kits

  • Complete Transformer Testing

  • - PF, PCB & Dissolved Gas Analysis

  • Self Powering Generator

  • On-Site Testing & Analysis

  • Vacuum Filling & Start-up

  • Reclamation & Retesting

  • Samples Obtained On-Site


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For more information

www.cutler-hammer.com

(Coming Soon: a web based “Reliability Calculator” to simplify these calculations)


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