IEEE Power & Energy Magazine - July/August 2020 - 56

needed to enable flexible islanding of the renewable resources
that would further increase resilience by decreasing the probability and duration of customers' outage times.
One challenge is to quantify the technical improvement of
resilience in terms of reducing the probability and duration
of unsupplied load by installing DG islanding capability.
The evaluation of socioeconomic benefits and the justification of accompanying costs present challenges of their own.
These technical and economical evaluation challenges and
technical options are addressed later in this article.

Resilience: Beyond Reliability
Since it was first introduced to power systems by Holling
in 1973, the concept of resilience has found its way from
ecology into engineering. The focus has been on natural
phenomena such as extreme weather events. Resilience, in
contrast to reliability, deals with the long tail of high-impact/
low-probability events. Figure 2 shows examples of such
events, where the arrows indicate the various times between
the first resupply and the final system restoration. Dotted
lines show time spans when only a smaller section of the
system was still unsupplied.
In contrast to these rare examples of blackout events,
faults regularly occur in the power system that affect relatively few customers, normally only for seconds or minutes and very infrequently for a few hours. In Germany, for
instance, about 150,000 interruptions that exceed 3 min for
low-voltage (LV) end customers are registered annually.
However, these large numbers only increase the System
Average Interruption Duration Index (SAIDI) by approximately 2 min/year per end customer at the LV level. The
total SAIDI is about 12-15 min/year, which does not consider extreme event (resilience-related) outages in these general reliability statistics.

The design and operation of power systems typically comply
with the following priorities:
1) Safety first: Direct harm to the health or even life of
humans is to be avoided.
2) Damage protection: The power system's components
are to be protected from damage, i.e., components are
allowed (sometimes even required) to disconnect instead of being destroyed (e.g., from an overload).
3) Security of supply: All customers must be supplied.
4) Power system optimization: The remaining flexibility
allows optimizing power system operation regarding
parameters such as cost-efficiency (e.g., economic dispatch), minimization of losses, increasing life expectancy of components, and so on.

Consumer Perspective
From a consumer perspective, the most relevant metric is
the supply of load. Customer satisfaction is achieved when
demand is met within secure boundaries of voltage and frequency where devices can operate without interruptions.

Operator Perspective
The power system operators' task of meeting customer requirements is fulfilled by controlling the voltages, frequencies, and
currents within the grid under normal conditions. Technically,
there is a huge degree of freedom when it comes to the operational strategies of dealing with power system phenomena that
result from operation itself, like line switching or transformer
tap changes, as well as from external effects, like lightning
overvoltages or short circuits.
A grid operator normally would only supply consumers
when a certain level of power quality can be guaranteed in terms
of interruptions, frequency, and voltage stability. Therefore, in

2012 North India

620
People Affected (Million)

Metrics in Power System Applications

2003 Italy

55

2003 Northeast America

2019 South America
15

0.26

2006 European System Split

2015 Ukraine Cyberattack

Reliability
2

2005 Münsterland Snow Chaos

Resilience
8

16

100
Duration (h)

figure 2. Some examples of big blackouts and how to distinguish reliability from resilience.
56

ieee power & energy magazine

july/august 2020



IEEE Power & Energy Magazine - July/August 2020

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - July/August 2020

Contents
IEEE Power & Energy Magazine - July/August 2020 - Cover1
IEEE Power & Energy Magazine - July/August 2020 - Cover2
IEEE Power & Energy Magazine - July/August 2020 - Contents
IEEE Power & Energy Magazine - July/August 2020 - 2
IEEE Power & Energy Magazine - July/August 2020 - 3
IEEE Power & Energy Magazine - July/August 2020 - 4
IEEE Power & Energy Magazine - July/August 2020 - 5
IEEE Power & Energy Magazine - July/August 2020 - 6
IEEE Power & Energy Magazine - July/August 2020 - 7
IEEE Power & Energy Magazine - July/August 2020 - 8
IEEE Power & Energy Magazine - July/August 2020 - 9
IEEE Power & Energy Magazine - July/August 2020 - 10
IEEE Power & Energy Magazine - July/August 2020 - 11
IEEE Power & Energy Magazine - July/August 2020 - 12
IEEE Power & Energy Magazine - July/August 2020 - 13
IEEE Power & Energy Magazine - July/August 2020 - 14
IEEE Power & Energy Magazine - July/August 2020 - 15
IEEE Power & Energy Magazine - July/August 2020 - 16
IEEE Power & Energy Magazine - July/August 2020 - 17
IEEE Power & Energy Magazine - July/August 2020 - 18
IEEE Power & Energy Magazine - July/August 2020 - 19
IEEE Power & Energy Magazine - July/August 2020 - 20
IEEE Power & Energy Magazine - July/August 2020 - 21
IEEE Power & Energy Magazine - July/August 2020 - 22
IEEE Power & Energy Magazine - July/August 2020 - 23
IEEE Power & Energy Magazine - July/August 2020 - 24
IEEE Power & Energy Magazine - July/August 2020 - 25
IEEE Power & Energy Magazine - July/August 2020 - 26
IEEE Power & Energy Magazine - July/August 2020 - 27
IEEE Power & Energy Magazine - July/August 2020 - 28
IEEE Power & Energy Magazine - July/August 2020 - 29
IEEE Power & Energy Magazine - July/August 2020 - 30
IEEE Power & Energy Magazine - July/August 2020 - 31
IEEE Power & Energy Magazine - July/August 2020 - 32
IEEE Power & Energy Magazine - July/August 2020 - 33
IEEE Power & Energy Magazine - July/August 2020 - 34
IEEE Power & Energy Magazine - July/August 2020 - 35
IEEE Power & Energy Magazine - July/August 2020 - 36
IEEE Power & Energy Magazine - July/August 2020 - 37
IEEE Power & Energy Magazine - July/August 2020 - 38
IEEE Power & Energy Magazine - July/August 2020 - 39
IEEE Power & Energy Magazine - July/August 2020 - 40
IEEE Power & Energy Magazine - July/August 2020 - 41
IEEE Power & Energy Magazine - July/August 2020 - 42
IEEE Power & Energy Magazine - July/August 2020 - 43
IEEE Power & Energy Magazine - July/August 2020 - 44
IEEE Power & Energy Magazine - July/August 2020 - 45
IEEE Power & Energy Magazine - July/August 2020 - 46
IEEE Power & Energy Magazine - July/August 2020 - 47
IEEE Power & Energy Magazine - July/August 2020 - 48
IEEE Power & Energy Magazine - July/August 2020 - 49
IEEE Power & Energy Magazine - July/August 2020 - 50
IEEE Power & Energy Magazine - July/August 2020 - 51
IEEE Power & Energy Magazine - July/August 2020 - 52
IEEE Power & Energy Magazine - July/August 2020 - 53
IEEE Power & Energy Magazine - July/August 2020 - 54
IEEE Power & Energy Magazine - July/August 2020 - 55
IEEE Power & Energy Magazine - July/August 2020 - 56
IEEE Power & Energy Magazine - July/August 2020 - 57
IEEE Power & Energy Magazine - July/August 2020 - 58
IEEE Power & Energy Magazine - July/August 2020 - 59
IEEE Power & Energy Magazine - July/August 2020 - 60
IEEE Power & Energy Magazine - July/August 2020 - 61
IEEE Power & Energy Magazine - July/August 2020 - 62
IEEE Power & Energy Magazine - July/August 2020 - 63
IEEE Power & Energy Magazine - July/August 2020 - 64
IEEE Power & Energy Magazine - July/August 2020 - 65
IEEE Power & Energy Magazine - July/August 2020 - 66
IEEE Power & Energy Magazine - July/August 2020 - 67
IEEE Power & Energy Magazine - July/August 2020 - 68
IEEE Power & Energy Magazine - July/August 2020 - 69
IEEE Power & Energy Magazine - July/August 2020 - 70
IEEE Power & Energy Magazine - July/August 2020 - 71
IEEE Power & Energy Magazine - July/August 2020 - 72
IEEE Power & Energy Magazine - July/August 2020 - 73
IEEE Power & Energy Magazine - July/August 2020 - 74
IEEE Power & Energy Magazine - July/August 2020 - 75
IEEE Power & Energy Magazine - July/August 2020 - 76
IEEE Power & Energy Magazine - July/August 2020 - 77
IEEE Power & Energy Magazine - July/August 2020 - 78
IEEE Power & Energy Magazine - July/August 2020 - 79
IEEE Power & Energy Magazine - July/August 2020 - 80
IEEE Power & Energy Magazine - July/August 2020 - 81
IEEE Power & Energy Magazine - July/August 2020 - 82
IEEE Power & Energy Magazine - July/August 2020 - 83
IEEE Power & Energy Magazine - July/August 2020 - 84
IEEE Power & Energy Magazine - July/August 2020 - 85
IEEE Power & Energy Magazine - July/August 2020 - 86
IEEE Power & Energy Magazine - July/August 2020 - 87
IEEE Power & Energy Magazine - July/August 2020 - 88
IEEE Power & Energy Magazine - July/August 2020 - 89
IEEE Power & Energy Magazine - July/August 2020 - 90
IEEE Power & Energy Magazine - July/August 2020 - 91
IEEE Power & Energy Magazine - July/August 2020 - 92
IEEE Power & Energy Magazine - July/August 2020 - Cover3
IEEE Power & Energy Magazine - July/August 2020 - Cover4
https://www.nxtbook.com/nxtbooks/pes/powerenergy_091020
https://www.nxtbook.com/nxtbooks/pes/powerenergy_070820
https://www.nxtbook.com/nxtbooks/pes/powerenergy_050620
https://www.nxtbook.com/nxtbooks/pes/powerenergy_030420
https://www.nxtbook.com/nxtbooks/pes/powerenergy_010220
https://www.nxtbook.com/nxtbooks/pes/powerenergy_111219
https://www.nxtbook.com/nxtbooks/pes/powerenergy_091019
https://www.nxtbook.com/nxtbooks/pes/powerenergy_070819
https://www.nxtbook.com/nxtbooks/pes/powerenergy_050619
https://www.nxtbook.com/nxtbooks/pes/powerenergy_030419
https://www.nxtbook.com/nxtbooks/pes/powerenergy_010219
https://www.nxtbook.com/nxtbooks/pes/powerenergy_111218
https://www.nxtbook.com/nxtbooks/pes/powerenergy_091018
https://www.nxtbook.com/nxtbooks/pes/powerenergy_070818
https://www.nxtbook.com/nxtbooks/pes/powerenergy_050618
https://www.nxtbook.com/nxtbooks/pes/powerenergy_030418
https://www.nxtbook.com/nxtbooks/pes/powerenergy_010218
https://www.nxtbook.com/nxtbooks/pes/powerenergy_111217
https://www.nxtbook.com/nxtbooks/pes/powerenergy_091017
https://www.nxtbook.com/nxtbooks/pes/powerenergy_070817
https://www.nxtbook.com/nxtbooks/pes/powerenergy_050617
https://www.nxtbook.com/nxtbooks/pes/powerenergy_030417
https://www.nxtbook.com/nxtbooks/pes/powerenergy_010217
https://www.nxtbook.com/nxtbooks/pes/powerenergy_111216
https://www.nxtbook.com/nxtbooks/pes/powerenergy_091016
https://www.nxtbook.com/nxtbooks/pes/powerenergy_070816
https://www.nxtbook.com/nxtbooks/pes/powerenergy_050616
https://www.nxtbook.com/nxtbooks/pes/powerenergy_030416
https://www.nxtbook.com/nxtbooks/pes/powerenergy_010216
https://www.nxtbook.com/nxtbooks/ieee/powerenergy_010216
https://www.nxtbook.com/nxtbooks/pes/powerenergy_111215
https://www.nxtbook.com/nxtbooks/pes/powerenergy_091015
https://www.nxtbook.com/nxtbooks/pes/powerenergy_070815
https://www.nxtbook.com/nxtbooks/pes/powerenergy_050615
https://www.nxtbook.com/nxtbooks/pes/powerenergy_030415
https://www.nxtbook.com/nxtbooks/pes/powerenergy_010215
https://www.nxtbook.com/nxtbooks/pes/powerenergy_111214
https://www.nxtbook.com/nxtbooks/pes/powerenergy_091014
https://www.nxtbook.com/nxtbooks/pes/powerenergy_070814
https://www.nxtbook.com/nxtbooks/pes/powerenergy_050614
https://www.nxtbook.com/nxtbooks/pes/powerenergy_030414
https://www.nxtbook.com/nxtbooks/pes/powerenergy_010214
https://www.nxtbookmedia.com