IEEE Power & Energy Magazine - May/June 2017 - 34

OLTCs that use a few local
field measurements to control
the voltage in the feeders (widearea control, WAC) are effecHC Increase
tive in only 48% of the feeders.
Average
Relative Standard
A centralized solution that comValue [%] Deviation
bines OLTC and DG control
produces good results in only
67.00
0.57
20% of the feeders. In the rest of
64.53
0.67
cases, as additional generation
62.99
1.38
is added, many feeders become
thermally constrained, and this
53.36
1.27
voltage-control solution is ineffective. Potentially more expen20.02
0.19
sive solutions like curtailment or
classical grid reinforcement are
HC Increase
applicable everywhere.
Average
Relative Standard
System performance is deValue [%] Deviation
pendent on many factors. Ex37.75
2.87
perience shows that a centralized solution using coordinated
37.13
1.62
OLTC and DRESs allows for
34.81
3.10
the highest amounts of HC.
Coordinated operation can be
29.72
3.53
achieved using a distribution
13.89
2.25
state estimator or an OPF to
10.83
0.39
establish the best settings at
each time. On average, the introduction of an OPF triples the
HC of a VVC system and almost doubles the effectiveness of a
WAC and VVC solution.
The combined effect of OLTCs used at primary and secondary substations is also an interesting case. Utilities around
the world use high-voltage (HV)/MV transformers equipped
with OLTC to control voltage levels [Figure 5(a)]. This has
some limitations when some of the MV feeders have contrasting voltage issues. The combined use of OLTC at both
HV/MV and MV/LV transformers can provide much more
flexibility for managing voltages, increasing HC up to 179%
in our experiments.
An alternative approach is inserting autotransformers in
the middle of the problematic MV lines [Figure 5(b), the
MV side] to correct these contrasting voltage levels. Then
the flexibility can be doubled at the MV level to absorb the
LV variations due to generators and loads. When LV lines of
a certain secondary substation present contrasting voltage
levels, introducing autotransformers [Figure 5(b), the LV
side] in some LV lines also increases the flexibility of the
whole system. The problem with this and similar ideas is the
cost of the new elements, but the potential to increase HC
and the effectiveness of existing assets is enormous.
Flexibility can be also obtained from third parties [Figure 5(c)]
such as generators and consumers. Active demand techniques
or energy storage installed at customers are some of the possibilities to regulate the loads in the lines. In some countries,

table 1. The HC increase resulting from applying
different SG solutions in the studied networks.
Centralized SG Solutions

Demo

MV centralized voltage control with ...

Germany

Field measurements-OLTC

Spain

OLTC + STATCOM control

Austria

Field measurements-OLTC + DG reactive
power control

Austria

Field measurements-OLTC control

Spain

STATCOM control

Distributed SG Solutions

Demo

MV distributed voltage control with...

Germany

AVR

France

DG reactive power control (droop Q-V control)

France

DG reactive power control [fixed tan(phi)]

Italy

OLTC + DG reactive power control

Greece

DG curtailment + DG reactive power control

Greece

DG curtailment

1.0

0.20

0.8

0.16

0.6

0.12

0.4

0.08

0.2

0.04

0.0

pdf

cdf

voltage-control solutions appear to be the most appropriate given
the large proportion of affected feeders. However, it is still necessary to test the applicability of each solution on real networks.
In our study, the network selection from different countries
showed that voltage-control solutions based on a local control
of reactive power from the DG inverters (volt-var control, VVC)
can successfully increase the HC in 60% of the feeders.

10 20 30 40 50 60 70 80 90 100
% Loading

figure 4. The probability distribution function (pdf) of
distribution grids from one Austrian DSO in function of
the loading reserve. The voltage-constrained feeders are
in blue, loading-constrained feeders are in red, and both
voltage- and loading-constrained feeders are in magenta.
The cumulated density function (cdf) of these grids in
function of the loading reserve is shown in black.
34

ieee power & energy magazine

may/june 2017



Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - May/June 2017

IEEE Power & Energy Magazine - May/June 2017 - Cover1
IEEE Power & Energy Magazine - May/June 2017 - Cover2
IEEE Power & Energy Magazine - May/June 2017 - 1
IEEE Power & Energy Magazine - May/June 2017 - 2
IEEE Power & Energy Magazine - May/June 2017 - 3
IEEE Power & Energy Magazine - May/June 2017 - 4
IEEE Power & Energy Magazine - May/June 2017 - 5
IEEE Power & Energy Magazine - May/June 2017 - 6
IEEE Power & Energy Magazine - May/June 2017 - 7
IEEE Power & Energy Magazine - May/June 2017 - 8
IEEE Power & Energy Magazine - May/June 2017 - 9
IEEE Power & Energy Magazine - May/June 2017 - 10
IEEE Power & Energy Magazine - May/June 2017 - 11
IEEE Power & Energy Magazine - May/June 2017 - 12
IEEE Power & Energy Magazine - May/June 2017 - 13
IEEE Power & Energy Magazine - May/June 2017 - 14
IEEE Power & Energy Magazine - May/June 2017 - 15
IEEE Power & Energy Magazine - May/June 2017 - 16
IEEE Power & Energy Magazine - May/June 2017 - 17
IEEE Power & Energy Magazine - May/June 2017 - 18
IEEE Power & Energy Magazine - May/June 2017 - 19
IEEE Power & Energy Magazine - May/June 2017 - 20
IEEE Power & Energy Magazine - May/June 2017 - 21
IEEE Power & Energy Magazine - May/June 2017 - 22
IEEE Power & Energy Magazine - May/June 2017 - 23
IEEE Power & Energy Magazine - May/June 2017 - 24
IEEE Power & Energy Magazine - May/June 2017 - 25
IEEE Power & Energy Magazine - May/June 2017 - 26
IEEE Power & Energy Magazine - May/June 2017 - 27
IEEE Power & Energy Magazine - May/June 2017 - 28
IEEE Power & Energy Magazine - May/June 2017 - 29
IEEE Power & Energy Magazine - May/June 2017 - 30
IEEE Power & Energy Magazine - May/June 2017 - 31
IEEE Power & Energy Magazine - May/June 2017 - 32
IEEE Power & Energy Magazine - May/June 2017 - 33
IEEE Power & Energy Magazine - May/June 2017 - 34
IEEE Power & Energy Magazine - May/June 2017 - 35
IEEE Power & Energy Magazine - May/June 2017 - 36
IEEE Power & Energy Magazine - May/June 2017 - 37
IEEE Power & Energy Magazine - May/June 2017 - 38
IEEE Power & Energy Magazine - May/June 2017 - 39
IEEE Power & Energy Magazine - May/June 2017 - 40
IEEE Power & Energy Magazine - May/June 2017 - 41
IEEE Power & Energy Magazine - May/June 2017 - 42
IEEE Power & Energy Magazine - May/June 2017 - 43
IEEE Power & Energy Magazine - May/June 2017 - 44
IEEE Power & Energy Magazine - May/June 2017 - 45
IEEE Power & Energy Magazine - May/June 2017 - 46
IEEE Power & Energy Magazine - May/June 2017 - 47
IEEE Power & Energy Magazine - May/June 2017 - 48
IEEE Power & Energy Magazine - May/June 2017 - 49
IEEE Power & Energy Magazine - May/June 2017 - 50
IEEE Power & Energy Magazine - May/June 2017 - 51
IEEE Power & Energy Magazine - May/June 2017 - 52
IEEE Power & Energy Magazine - May/June 2017 - 53
IEEE Power & Energy Magazine - May/June 2017 - 54
IEEE Power & Energy Magazine - May/June 2017 - 55
IEEE Power & Energy Magazine - May/June 2017 - 56
IEEE Power & Energy Magazine - May/June 2017 - 57
IEEE Power & Energy Magazine - May/June 2017 - 58
IEEE Power & Energy Magazine - May/June 2017 - 59
IEEE Power & Energy Magazine - May/June 2017 - 60
IEEE Power & Energy Magazine - May/June 2017 - 61
IEEE Power & Energy Magazine - May/June 2017 - 62
IEEE Power & Energy Magazine - May/June 2017 - 63
IEEE Power & Energy Magazine - May/June 2017 - 64
IEEE Power & Energy Magazine - May/June 2017 - 65
IEEE Power & Energy Magazine - May/June 2017 - 66
IEEE Power & Energy Magazine - May/June 2017 - 67
IEEE Power & Energy Magazine - May/June 2017 - 68
IEEE Power & Energy Magazine - May/June 2017 - 69
IEEE Power & Energy Magazine - May/June 2017 - 70
IEEE Power & Energy Magazine - May/June 2017 - 71
IEEE Power & Energy Magazine - May/June 2017 - 72
IEEE Power & Energy Magazine - May/June 2017 - 73
IEEE Power & Energy Magazine - May/June 2017 - 74
IEEE Power & Energy Magazine - May/June 2017 - 75
IEEE Power & Energy Magazine - May/June 2017 - 76
IEEE Power & Energy Magazine - May/June 2017 - 77
IEEE Power & Energy Magazine - May/June 2017 - 78
IEEE Power & Energy Magazine - May/June 2017 - 79
IEEE Power & Energy Magazine - May/June 2017 - 80
IEEE Power & Energy Magazine - May/June 2017 - 81
IEEE Power & Energy Magazine - May/June 2017 - 82
IEEE Power & Energy Magazine - May/June 2017 - 83
IEEE Power & Energy Magazine - May/June 2017 - 84
IEEE Power & Energy Magazine - May/June 2017 - 85
IEEE Power & Energy Magazine - May/June 2017 - 86
IEEE Power & Energy Magazine - May/June 2017 - 87
IEEE Power & Energy Magazine - May/June 2017 - 88
IEEE Power & Energy Magazine - May/June 2017 - 89
IEEE Power & Energy Magazine - May/June 2017 - 90
IEEE Power & Energy Magazine - May/June 2017 - 91
IEEE Power & Energy Magazine - May/June 2017 - 92
IEEE Power & Energy Magazine - May/June 2017 - 93
IEEE Power & Energy Magazine - May/June 2017 - 94
IEEE Power & Energy Magazine - May/June 2017 - 95
IEEE Power & Energy Magazine - May/June 2017 - 96
IEEE Power & Energy Magazine - May/June 2017 - 97
IEEE Power & Energy Magazine - May/June 2017 - 98
IEEE Power & Energy Magazine - May/June 2017 - 99
IEEE Power & Energy Magazine - May/June 2017 - 100
IEEE Power & Energy Magazine - May/June 2017 - 101
IEEE Power & Energy Magazine - May/June 2017 - 102
IEEE Power & Energy Magazine - May/June 2017 - 103
IEEE Power & Energy Magazine - May/June 2017 - 104
IEEE Power & Energy Magazine - May/June 2017 - Cover3
IEEE Power & Energy Magazine - May/June 2017 - Cover4
https://www.nxtbook.com/nxtbooks/ieee/powerelectronics_september2021
https://www.nxtbook.com/nxtbooks/pes/powerenergy_091021
https://www.nxtbook.com/nxtbooks/pes/powerenergy_070821
https://www.nxtbook.com/nxtbooks/pes/powerenergy_050621
https://www.nxtbook.com/nxtbooks/pes/powerenergy_030421
https://www.nxtbook.com/nxtbooks/pes/powerenergy_010221
https://www.nxtbook.com/nxtbooks/pes/powerenergy_111220
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