IEEE Power & Energy Magazine - May/June 2019 - 41

cases, missing data are mathematically interpolated. in addition to data concentration, pdcs can perform many more
tasks by leveraging their computational capability:
1) data archiving: continuous archival of data locally
on the hard drive or solid-state drive in required data
formats (locally and remotely retrievable for further
analysis)
2) access control: support for various access control functions, such as role-based account authentication, antivirus, strong passwords, access logs, and port auditing to
achieve north american electric reliability corporation critical infrastructure protection compliance
3) data validation and statistics: validation of received
pMU data using predefined validation criteria while
monitoring the data quality, latency, and so on.
Multiple pdcs may be located at key substations and
communicate through the WaMpac network via a wide
range of media, such as dedicated optical fiber, satellite, radio
frequency, microwave, and metal wire. local pdcs can also
communicate with super pdcs located at transmission system operators and serve situational awareness and WaMpac applications. the time-aligned synchrophasor data can
be used in advanced data analysis tools, situational awareness software, and wide-area controllers to allow operators
to simulate, visualize, analyze, and control an interconnected
bulk power system as a whole.
in the WaMpac platform, the synchrophasor data are
processed through multiple stages, such as generation, transmission, and alignment, and finally taken as inputs into the
WaMpac applications. during each stage, data may potentially be compromised by cyberattackers who can eavesdrop,
disrupt, and manipulate both the measurement and control

command data that are processed and transmitted through
the WaMpac platform.

Vulnerabilities and Consequences
With these control and communication concerns in mind,
potential vulnerabilities of hvdc and digitalized ac power
systems must be addressed. communication channels and
the wide range of digital devices through which these control systems are implemented create potential vulnerabilities
in software and firmware. Such liabilities may be exploited
by attackers wishing to do harm.
the controllers described are frequently facilitated by
Scada systems employing plcs, remote terminal units,
sensors, and various other data collection and end devices.
Scada software is necessary to process and distribute the
aggregated data to control rooms and actuators for control
actions to be taken. recent high-impact cyberattacks taken
against Scada systems (plc central processing units, in
particular) have shown the potential for malicious actors
to covertly wreak havoc. the Stuxnet malicious computer
worm showed that all energy systems reliant on Scada
control and communication may be at risk. in fact, a recent
study performed by a private cybersecurity firm revealed
that nearly 40% of all industrial control systems currently in
operation were subject to at least one attempted cyberattack
in the final six months of 2017.
in addition to the WaMpac and Scada concerns
previously described, their interaction with hvdc systems
must be properly secured. Worldwide, more than 100 hvdc
transmission lines are in use, with approximately 50 additional back-to-back converter stations in operation. While
there are fewer hvdc systems than ac transmission lines,

WAMPAC Applications
GPS Synchronization Signal

Control Center and SCADA
Super PDC

HVdc
Local WAMPAC
Controller
Applications

GPS Clock

RTU

PMU

PDC

IED

MU
CT

PDC
PMU

CB
VT

IED

MU
CT

RTU

CB
VT

figure 1. A schematic of the WAMPAC platform. CT: current transformer; MU: merging unit; RTU: remote terminal unit;
VT: voltage transformer.
may/june 2019

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IEEE Power & Energy Magazine - May/June 2019

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - May/June 2019