IEEE Electrification Magazine - December 2015 - 29

Figure 7. GIC measurements at several AEP locations during a 24-h period.

AEP has subsequently worked with others using
now commercially available software to simulate GIC
flows for various GMD scenarios and steady-state system behavior during GMD events. Simulated maximum neutral currents, for a 2-V/km E-field at Earth's
surface, were on the order of 260 A. Figure 8 shows the
GIC flow and voltage deviation in the presence of a
benchmarked GMD event (i.e., E-field of 3.52 V/km for
the AEP PJM area).

Effects of a Transformer Neutral GIC Blocking Device
The concept of transformer neutral blocking devices
(NBDs) such as capacitors or low-ohmic resistors has
been proposed by some researchers, and a prototype
was installed in a pilot project, but the effectiveness to
mitigate GMD system impact and the long-term reliability of the device need to be evaluated to convince
utilities to take further action on deploying such a
device. To further evaluate the effectiveness of transformer NBDs, GIC redistributions due to various percentages of GIC NBD placements were studied based
on a uniform rotating geoelectric field.
The evaluation included
xx
the effect of a transformer neutral GIC (N-GIC) blocking device on transformer effective GIC (E-GIC) and
GIC redistribution
xx
the impact of a GIC blocking device on transformer
reactive power absorption and its effectiveness in
reducing total transformer reactive power absorption.
The NBD effectiveness studies demonstrate that the GIC
blocking device will block N-GIC flow through a transformer

grounding cable. However, the transformer NBD will also
divert the GIC flow to where transformer high-side winding
is wye-grounded and electrically adjacent to the transformers with N-GIC blocked so that GIC levels might increase in
these neighboring transformers, particularly those that
exhibit lower levels of GIC flow under the no-blocking condition. Hence, the total system E-GIC does not reduce proportionally to the N-GIC blocked.
To quantify the effect of transformer NBD, GIC flows
were simulated by applying a rotating uniform geoelectric
field of 3.52 V/km to the studied system based on the

Voltage/PU Difference

Figure 8. GIC flow and voltage deviation.

IEEE Elec trific ation Magazine / d ec em be r 2 0 1 5

29



Table of Contents for the Digital Edition of IEEE Electrification Magazine - December 2015

IEEE Electrification Magazine - December 2015 - Cover1
IEEE Electrification Magazine - December 2015 - Cover2
IEEE Electrification Magazine - December 2015 - 1
IEEE Electrification Magazine - December 2015 - 2
IEEE Electrification Magazine - December 2015 - 3
IEEE Electrification Magazine - December 2015 - 4
IEEE Electrification Magazine - December 2015 - 5
IEEE Electrification Magazine - December 2015 - 6
IEEE Electrification Magazine - December 2015 - 7
IEEE Electrification Magazine - December 2015 - 8
IEEE Electrification Magazine - December 2015 - 9
IEEE Electrification Magazine - December 2015 - 10
IEEE Electrification Magazine - December 2015 - 11
IEEE Electrification Magazine - December 2015 - 12
IEEE Electrification Magazine - December 2015 - 13
IEEE Electrification Magazine - December 2015 - 14
IEEE Electrification Magazine - December 2015 - 15
IEEE Electrification Magazine - December 2015 - 16
IEEE Electrification Magazine - December 2015 - 17
IEEE Electrification Magazine - December 2015 - 18
IEEE Electrification Magazine - December 2015 - 19
IEEE Electrification Magazine - December 2015 - 20
IEEE Electrification Magazine - December 2015 - 21
IEEE Electrification Magazine - December 2015 - 22
IEEE Electrification Magazine - December 2015 - 23
IEEE Electrification Magazine - December 2015 - 24
IEEE Electrification Magazine - December 2015 - 25
IEEE Electrification Magazine - December 2015 - 26
IEEE Electrification Magazine - December 2015 - 27
IEEE Electrification Magazine - December 2015 - 28
IEEE Electrification Magazine - December 2015 - 29
IEEE Electrification Magazine - December 2015 - 30
IEEE Electrification Magazine - December 2015 - 31
IEEE Electrification Magazine - December 2015 - 32
IEEE Electrification Magazine - December 2015 - 33
IEEE Electrification Magazine - December 2015 - 34
IEEE Electrification Magazine - December 2015 - 35
IEEE Electrification Magazine - December 2015 - 36
IEEE Electrification Magazine - December 2015 - 37
IEEE Electrification Magazine - December 2015 - 38
IEEE Electrification Magazine - December 2015 - 39
IEEE Electrification Magazine - December 2015 - 40
IEEE Electrification Magazine - December 2015 - 41
IEEE Electrification Magazine - December 2015 - 42
IEEE Electrification Magazine - December 2015 - 43
IEEE Electrification Magazine - December 2015 - 44
IEEE Electrification Magazine - December 2015 - 45
IEEE Electrification Magazine - December 2015 - 46
IEEE Electrification Magazine - December 2015 - 47
IEEE Electrification Magazine - December 2015 - 48
IEEE Electrification Magazine - December 2015 - 49
IEEE Electrification Magazine - December 2015 - 50
IEEE Electrification Magazine - December 2015 - 51
IEEE Electrification Magazine - December 2015 - 52
IEEE Electrification Magazine - December 2015 - 53
IEEE Electrification Magazine - December 2015 - 54
IEEE Electrification Magazine - December 2015 - 55
IEEE Electrification Magazine - December 2015 - 56
IEEE Electrification Magazine - December 2015 - 57
IEEE Electrification Magazine - December 2015 - 58
IEEE Electrification Magazine - December 2015 - 59
IEEE Electrification Magazine - December 2015 - 60
IEEE Electrification Magazine - December 2015 - 61
IEEE Electrification Magazine - December 2015 - 62
IEEE Electrification Magazine - December 2015 - 63
IEEE Electrification Magazine - December 2015 - 64
IEEE Electrification Magazine - December 2015 - Cover3
IEEE Electrification Magazine - December 2015 - Cover4
http://www.nxtbook.com/nxtbooks/pes/electrification_december2019
http://www.nxtbook.com/nxtbooks/pes/electrification_september2019
http://www.nxtbook.com/nxtbooks/pes/electrification_june2019
http://www.nxtbook.com/nxtbooks/pes/electrification_march2019
http://www.nxtbook.com/nxtbooks/pes/electrification_december2018
http://www.nxtbook.com/nxtbooks/pes/electrification_september2018
http://www.nxtbook.com/nxtbooks/pes/electrification_june2018
http://www.nxtbook.com/nxtbooks/pes/electrification_december2017
http://www.nxtbook.com/nxtbooks/pes/electrification_september2017
http://www.nxtbook.com/nxtbooks/pes/electrification_march2018
http://www.nxtbook.com/nxtbooks/pes/electrification_june2017
http://www.nxtbook.com/nxtbooks/pes/electrification_march2017
http://www.nxtbook.com/nxtbooks/pes/electrification_june2016
http://www.nxtbook.com/nxtbooks/pes/electrification_december2016
http://www.nxtbook.com/nxtbooks/pes/electrification_september2016
http://www.nxtbook.com/nxtbooks/pes/electrification_december2015
http://www.nxtbook.com/nxtbooks/pes/electrification_march2016
http://www.nxtbook.com/nxtbooks/pes/electrification_march2015
http://www.nxtbook.com/nxtbooks/pes/electrification_june2015
http://www.nxtbook.com/nxtbooks/pes/electrification_september2015
http://www.nxtbook.com/nxtbooks/pes/electrification_march2014
http://www.nxtbook.com/nxtbooks/pes/electrification_june2014
http://www.nxtbook.com/nxtbooks/pes/electrification_september2014
http://www.nxtbook.com/nxtbooks/pes/electrification_december2014
http://www.nxtbook.com/nxtbooks/pes/electrification_december2013
http://www.nxtbook.com/nxtbooks/pes/electrification_september2013
http://www.nxtbookMEDIA.com