IEEE Electrification - December 2022 - 36

Substation
Substation
(a)
Load
Reference Load
(c)
Substation
(c)
Faults
Occur
(b)
(a)
Granular
Repair
Full
Repair
Figure 8. Service restoration scenarios of different types of distribution grids. (a) Conventional service restoration. (b) Service restoration with
reconfiguration. (c) Service restoration with grid-edge DERs. (d) Load restoration performance.
controllable resources in faulted sections. The presence of
grid-edge DERs can make significant differences both by
providing more reconfiguration options and by energizing
outage areas that cannot be picked up by the reconfiguration.
This happens because 1) grid-forming DERs, such as
PV systems and batteries, can form microgrids and can act
as generating resources together with other grid-following
generating resources to supply power to the load, and 2)
the flexibility of grid-edge DERs can alter the energy consumption
patterns of both normal sections and faultaffected
sections and thus can provide more feasible
options to reconnect loads if the normal sections have limited
extra capacity. Accordingly, the presence of grid-edge
DERs can improve the service restoration performance in
Critical Load Shed
500
400
300
200
100
Option 0
Option 1
Option 2
terms of the uninterrupted load supply, as described conceptually
in Figure 8(d).
To use grid-edge DERs to improve service restoration in
practice, the DER flexibility is first calculated, and then
advanced DER controls are implemented and can be integrated
with traditional fault location, isolation, and service
restoration (FLISR) applications. As an example, we implemented
our DER flexibility calculation and optimization
approach on the simulation model of a real distribution
system in Central Georgia Electric Membership Corporation.
We considered the solution logics of a commercial
FLISR product and designed two implementation options to
leverage the grid-edge DERs to extend the FLISR capability
in performing service restoration. Figure 9 shows the loadshedding
results obtained from
three scenarios.
Option 0 is the result obtained by
Time Steps
Figure 9. Load-shedding results obtained from three scenarios studied on a real distribution system
in Central Georgia Electric Membership Corporation.
36
IEEE Electrification Magazine / DECEMBER 2022
applying the commercial FLISR
product solution logics in which the
restoration is conducted by operating
the available tie switches and
evaluating whether the capacity of
the tie switches is no less than the
capacity of the loads that need to be
transferred from the faulted section.
Option 1 represents the results of
the first implementation, in which
we apply the advanced controls so
that the grid-edge DERs can operate
at their lower consumption trajectories.
In this manner, the decisions of
the tie switches are determined by
evaluating whether enough capacity
can be spared from the normal sections
to pick up the loads in the
faulted sections but operate with
Time
(b)
Load Shed (kW)
00:00
01:00
02:00
03:00
04:00
05:00
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00

IEEE Electrification - December 2022

Table of Contents for the Digital Edition of IEEE Electrification - December 2022