  The electric power system is a cyber-physical system with power flow in the
physical system and information flow in the cyber. Simulation is crucial to
understanding the dynamics and control of electric power systems yet the
underlying communication system has historically been ignored in these studies.
This paper aims at meeting the increasing needs to simulate the operations of a
real power system including the physical system, the energy management system,
the communication system, and the emerging wide-area measurement-based
controls. This paper proposes a cyber-physical testbed design and
implementation for verifying and demonstrating wide-area control methods based
on streaming telemetry and phasor measurement unit data. The proposed decoupled
architecture is composed of a differential algebraic equation based physical
system simulator, a software-defined network, a scripting language environment
for prototyping an EMS system and a control system, all of which are integrated
over industry-standard communication protocols. The proposed testbed is
implemented using open-source software packages managed by a Python dispatcher.
Finally, demonstrations are presented to show two wide-area measurement-based
controls - system separation control and hierarchical voltage control, in the
implemented testbed.
