1

Indiana Utility Regulatory Commission

Electric Utility Reliability Report: 2002 – 2016

Each investor-owned electric utility (IOU) in Indiana is required to file a reliability report annually with

the Indiana Utility Regulatory Commission (IURC) in compliance with 170 IAC 4-1-23(e). This document

serves as a compilation of the reports filed for 2016 and provides historical data beginning in 2002. The

data are provided in summary tables early in the report and in complete tables at the end. Also included

is a graph for each IOU illustrating the trends experienced from 2002 through 2016.

The utilities provide the following three reliability indices in their reports:

• System Average Interruption Frequency Index (SAIFI): the average number of interruptions per

customer. It is calculated by dividing the total number of customer interruptions by the total

number of customers.

• System Average Interruption Duration Index (SAIDI): the average minutes of interruption per

customer. It is calculated by dividing the sum of all customer interruption durations (in minutes)

by the total number of customers.

• Customer Average Interruption Duration Index (CAIDI): the average duration of interruptions or

the time to restore service to interrupted customers. It is calculated by dividing SAIDI by SAIFI.

Each utility reports its reliability indices with and without major events. Major events are storms or

weather events that are more destructive than normal storm patterns. It is important to note that the

same definition of “major event” is not used by all utilities. However, Indiana IOUs define a major event

day (MED) using a standard provided by the Institute of Electrical and Electronics Engineers (IEEE

Standard 1366). It involves the calculation of a threshold in terms of SAIDI minutes based on data from

the previous five years. Any day the threshold is exceeded is a MED. The provision of indices that

exclude major events normalizes the data by eliminating interruptions over which the utilities have little

or no control. In addition, there can be great variation in major events (e.g., tornadoes, floods, ice

storms), the resulting damage, and the time necessary to make repairs.

The following table summarizes the number of MEDs each IOU reported for 2016. Although not

required, four of the IOUs also provided the number of major events, which indicates that one storm

system can potentially cause multiple major event days.

Utility Company Major Event Days Major Events

Duke Energy Indiana 4 4

Indiana Michigan Power 3 3

Indianapolis Power & Light 9 Not provided

NIPSCO 10 4

Vectren 3 3

Causes of interruptions other than MEDs can include equipment failures, accidents, and weather events

that do not meet the MED threshold. As an example, NIPSCO stated it experienced an additional 68

weather events it considered severe, but that did not meet the MED threshold.

2

The reliability indices should only be used to evaluate the performance of an individual utility company

over time. Direct comparisons of the utilities’ indices should be avoided. The size and geography of

service territories and the distribution of customers within them can vary greatly among the utilities,

complicating direct comparison of the indices. A map showing the service territories of the Indiana IOUs

is shown below. All other factors being equal, IOUs with compact service areas like Vectren and

Indianapolis Power and Light (IPL) should be able to respond to interruptions faster and individual

repairs could put a greater number of customers back online. That may, at least partially, explain

Vectren and IPL’s lower numbers for the duration indices of SAIDI and CAIDI.

Service Territories of Indiana Investor Owned Utilities

The following table provides the 2016 reliability indices without MEDs for the Indiana IOUs and a

comparison of the 2016 indices with their averages for the previous five years. Details for 2002 through

2016 are provided in the tables on pages 6 and 8.

Investor Owned Utilities

DUKE ENERGY

INDIANA MICHIGAN POWER

INDIANAPOLIS POWER & LIGHT

NIPSCO

VECTREN

3

Comparison of 2016 Indices to 2011-2015 Average Indices (Without Major Events)

2016 2011-

2015 Avg

Variance 2016 - Avg

% Variance

2016 - Avg

NIPSCO

SAIFI 0.99 0.85 0.14 17%

SAIDI 135.00 105.40 29.60 28%

CAIDI 136.00 124.00 12.00 10%

Duke

SAIFI 1.10 1.18 -0.08 -7%

SAIDI 142.49 138.80 3.69 3%

CAIDI 129.60 117.30 12.30 10%

IPL

SAIFI 0.74 0.73 0.02 2%

SAIDI 61.64 57.11 4.53 8%

CAIDI 82.85 78.78 4.07 5%

Vectren

SAIFI 0.82 1.00 -0.18 -18%

SAIDI 61.30 81.12 -19.82 -24%

CAIDI 74.40 78.84 -4.44 -6%

I&M

SAIFI 0.95 0.89 0.06 7%

SAIDI 152.90 138.34 14.56 11%

CAIDI 160.80 155.84 4.96 3%

The following graphs show the indices without MEDs of the five IOUs from 2002 through 2016.

4

5

6

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

NIP

SC

O

SA

IFI

1.1

51.4

51.2

21.0

91.2

11.0

61.1

10.8

80.9

40.9

20.8

30.7

80.8

40.8

70.9

9

SA

IDI

196.2

0350.4

0213.0

0181.0

0196.0

0180.0

0199.0

0140.0

0122.0

0126.0

0102.0

095.0

094.0

0110.0

0135.0

0

CA

IDI

170.6

0241.7

0175.0

0166.0

0163.0

0169.0

0179.0

0158.0

0130.0

0137.0

0123.0

0122.0

0111.0

0127.0

0136.0

0

Du

ke S

AIF

I1.3

61.2

21.2

11.2

71.3

21.2

31.2

61.3

01.3

21.2

71.2

91.1

71.1

61.0

31.1

0

SA

IDI

134.0

0127.0

0124.0

0138.0

0136.0

0133.0

0146.0

0133.0

0138.0

0146.0

0149.0

0138.0

0140.0

0121.0

0142.4

9

CA

IDI

98.0

0103.0

0102.0

0109.0

0103.0

0109.0

0116.0

0102.0

0104.0

0115.0

0115.0

0118.0

0121.0

0117.5

0129.6

0

IPL

SA

IFI

1.0

30.7

90.7

10.9

01.0

70.7

61.0

40.9

41.0

40.8

60.8

20.5

80.7

10.6

60.7

4

SA

IDI

73.8

065.7

053.2

066.5

0105.1

546.9

980.8

481.1

371.1

575.0

856.7

148.3

356.7

148.7

061.6

4

CA

IDI

72.0

083.2

074.5

073.9

098.0

161.7

077.6

886.2

368.1

387.6

369.5

782.7

880.2

473.7

082.8

5

Ve

ctr

en

SA

IFI

1.4

61.2

71.1

21.6

81.5

11.2

31.4

21.2

01.0

21.4

31.0

70.7

30.9

20.8

50.8

2

SA

IDI

164.0

0111.0

0106.8

0137.0

0151.0

089.0

0133.0

0110.0

089.7

0137.0

083.0

047.5

067.2

070.9

061.3

0

CA

IDI

107.0

087.0

095.4

082.0

0100.0

072.0

094.0

092.0

088.3

095.7

077.5

065.1

073.0

082.9

074.4

0

I&M

SA

IFI

1.1

20.9

51.2

51.0

01.1

21.1

11.1

20.8

30.7

40.9

90.9

10.7

40.7

71.0

50.9

5

SA

IDI

179.1

0128.5

0194.1

0170.7

0146.7

0139.1

0143.7

090.3

0111.3

0153.7

0136.7

0113.7

0127.5

0160.1

0152.9

0

CA

IDI

159.3

0135.0

0155.6

0171.1

0130.6

0125.6

0128.6

0108.8

0150.9

0156.1

0151.1

0154.0

0165.4

0152.6

0160.8

0

No

tes

SA

IFI: S

yste

m A

vera

ge In

terr

uptio

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requency In

dex; (#

of

custo

mers

who e

xperience o

uta

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/ (t

ota

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)

SA

IDI: S

yste

m A

vera

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terr

uptio

n D

ura

tion In

dex; (d

ura

tion o

r tim

e o

f serv

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terr

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ns)

/ (t

ota

l # o

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)

CA

IDI: C

usto

mer

Avera

ge In

terr

uptio

n D

ura

tion In

dex; (S

AID

I) / (

SA

IFI)

*Majo

r events

are

sto

rms o

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that are

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uctiv

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orm

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torm

pattern

s. T

he s

am

e d

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is n

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ll util

ties.

**N

IPS

CO

's 2

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eport

update

d v

alu

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or

2004-2

006 b

ased o

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ccepte

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dustr

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tandard

IEEE S

td 1

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Ele

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elia

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No

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ve

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*

7

2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Mean

NIPSCO 13 6 0 9 22 17 3 18 10 10 10.8

Duke 3 14 6 5 12 4 3 5 6 4 6.2

IPL 0 3 1 0 0 6 3 5 6 9 3.3

Vectren 0 4 2 0 2 4 1 6 2 3 2.4

I&M 3 8 2 6 4 9 3 5 4 3 4.7

Major Event Days for Investor Owned Utilities 2007-2016

8

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

NIP

SC

O

SA

IFI

1.4

11.6

51.3

81.2

41.4

02.2

31.8

00.8

81.3

61.3

81.4

41.4

51.5

31.1

61.2

6

SA

IDI

542.4

0498.0

0317.0

0258.0

0317.0

01073.0

0882.0

0140.0

0505.0

0371.0

0428.0

0520.0

0603.0

0248.0

0231.0

0

CA

IDI

384.7

0301.8

0229.0

0208.0

0227.0

0480.0

0490.0

0158.0

0372.0

0269.0

0297.0

0359.0

0395.0

0214.0

0184.0

0

Du

ke S

AIF

I1.5

71.5

81.6

61.5

91.6

31.4

12.4

81.7

61.5

82.0

71.5

21.3

81.3

11.2

71.3

4

SA

IDI

170.0

0201.0

0255.0

0282.0

0203.0

0178.0

0689.0

0293.0

0195.0

0630.0

0216.0

0257.0

0186.0

0211.0

0289.7

9

CA

IDI

109.0

0128.0

0153.0

0177.0

0125.0

0126.0

0278.0

0166.0

0124.0

0304.0

0143.0

0187.0

0142.0

0166.1

0216.6

9

IPL

SA

IFI

1.1

70.9

00.8

10.9

01.0

70.7

61.5

41.1

01.0

40.8

61.0

40.7

10.9

60.9

41.1

7

SA

IDI

132.9

098.0

076.7

066.5

0105.1

546.9

9358.9

8158.3

971.1

575.0

8124.9

292.3

0189.9

8219.4

5232.2

3

CA

IDI

113.3

0108.4

094.1

073.9

098.0

161.7

0232.9

6144.6

368.1

387.6

3119.6

6130.0

1198.6

3233.1

2198.4

8

Ve

ctr

en

SA

IFI

1.4

61.2

72.3

62.0

51.8

71.2

32.3

32.5

61.0

22.1

61.2

40.7

81.4

70.9

01.2

6

SA

IDI

164.0

0111.0

0932.4

0376.0

0241.0

089.0

0859.0

02889.0

089.7

0711.3

0117.3

060.1

0314.3

081.3

0260.9

0

CA

IDI

107.0

087.0

0394.7

0185.0

0128.0

072.0

0369.0

01126.0

088.3

0329.9

094.9

076.6

0213.5

090.6

0206.9

0

I&M

SA

IFI

1.6

81.5

61.4

21.3

11.2

41.2

41.6

30.9

10.9

81.1

21.3

90.9

60.9

61.2

41.0

6

SA

IDI

930.6

0594.2

0291.4

01131.6

0222.0

0199.4

01164.3

0121.5

0392.3

0258.0

01071.2

0374.5

0305.9

0390.3

0255.0

0

CA

IDI

553.5

0380.2

0204.7

0863.0

0178.7

0161.2

0712.8

0133.2

0399.8

0230.3

0772.5

0392.0

0317.8

0313.9

0240.6

0

No

tes

SA

IFI: S

yste

m A

vera

ge In

terr

uptio

n F

requency In

dex; (#

of

custo

mers

who e

xperience o

uta

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/ (t

ota

l # o

f custo

mers

)

SA

IDI: S

yste

m A

vera

ge In

terr

uptio

n D

ura

tion In

dex; (d

ura

tion o

r tim

e o

f serv

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uptio

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/ (t

ota

l # o

f custo

mers

)

CA

IDI: C

usto

mer

Avera

ge In

terr

uptio

n D

ura

tion In

dex; (S

AID

I) / (

SA

IFI)

*Majo

r events

are

sto

rms o

r w

eath

er

events

that are

more

destr

uctiv

e than n

orm

al s

torm

pattern

s. T

he s

am

e d

efiniti

on o

f "m

ajo

r event"

is n

ot used b

y a

ll util

ties.

**N

IPS

CO

's 2

007 r

eport

update

d v

alu

es f

or

2004-2

006 b

ased o

n a

ccepte

d in

dustr

y s

tandard

IEEE S

td 1

366 -

how

ever,

the a

bove v

alu

es r

eflect th

e o

rigin

al r

eport

s.

Ele

ctr

ic R

elia

bility

In

clu

din

g M

ajo

r E

ven

ts*