IEEE Power & Energy Magazine - March/April 2018 - 69

elements, and maintain the dynamic state of the aDMS
model topology.

Loss Optimization
the loss optimization mode is the normal mode of aDMS
and is used almost continually to improve the efficiency of
the grid though traditional distribution objectives, such as
managing reactive power flow (i.e., power factor correction)
and minimizing active power losses. all aDMS functionalities operate in this mode, including closed-loop VVO and
switching sequence list (SSL).

DSDR
the DSDr mode uses closed-loop VVO to implement
planned and economic-driven peak load reduction on the grid.
Collective experience shows that this mode is used for only a
small percentage of time, which can vary depending on the
annual conditions and the fluctuation of variables (e.g., fuel
costs) used when determining the economic dispatch order of
generation resources. the typical effect of DSDr mode on
system load is illustrated in Figure 2.

Emergency
the emergency mode executes nonoptimized voltage reduction in the grid with the objective of quickly reducing load in
response to unanticipated bulk system events. It is predefined
for a few (e.g., two) levels, with the expectation that the initial
level will be used more frequently in response to events such
as a generation unit tripping offline and the other levels (e.g.,
level 2, with a greater magnitude) will be used only under
extreme circumstances. this mode uses the existing functionality of voltage regulator control that ignores the specified time delay setting for tap change initiation-enabling fast
voltage reduction-and internally applies the specified reduction level to active bandcenter setting.
the time necessary to activate the mode meets the
requirement for maintaining proper generation contingency

reserves for compliance with north american Electric reliability Corporation (nErC) standard BaL-002-1. this provides an additional economic benefit when voltage reduction
is not active as a result of avoided fuel production costs. the
commands for emergency mode are developed and issued
by the aDMS SSL functionality and were designed to command each voltage regulator in the grid within the required
time frame. Because emergency mode is implemented only
under emergency conditions, customer voltage levels are
allowed within range B of the american national Standards
Institute C84.1 standard. the typical effect of emergency
mode on system load is illustrated in Figure 3.

Storm
the storm mode is used to further disable aDMS functionality when the state of the grid is expected to be in a high
degree of flux due to widespread outages, incorrect topology,
and unknown device state. It is similar to monitor and control
mode but with only LF function continuing to operate: ntLF,
SE, VVO and SSL do not run. the "heartbeat" functionality
needed to keep voltage regulator controls in their VVO closedloop or emergency modes also does not continue to run. this
has the effect of causing the voltage regulator control to return
to its default local automation settings and, in essence, changing the state of the grid from the previous aDMS mode.

Results and Benefits of Real-Life
Usage of Volt/Var Optimization
Overview
the Duke Energy Progress (DEP) distribution grid serves
over 1.5 million customers in north and South Carolina,
covering 34,000 mi2 of service area. It currently consists
of more than 400 transmission-to-distribution (t/D) substations, 6,700 VVO-controllable devices (voltage regulators and capacitor banks), and 11,500 total SCaDa grid
devices. aDMS was deployed as part of a six-year project

DEP: 7 January 2014
14.4
14.2

DSDR
Mode

Voltage Returned
to Normal

Load (GW)

DEP: 14 July 2014
7.6
7.4
7.2
7.0
6.8
6.6
6.4
6.2
6.0
5.8
5.6
5.4
9:30

14.0

Emergency
Mode
Emergency Level 2
Mode
Level 1

13.8
13.6
13.4

Voltage Returned
to Normal

13.2
11:51 14:12 16:34 18:58 21:20 23:43
Time (hh:mm)

figure 2. The DSDR mode effect.
march/april 2018

13.0
4:30

5:20

6:10
7:00
7:50
Time (hh:mm)

8:40

9:30

figure 3. Emergency mode effects.
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