  This paper introduces the messaging environment and the geographical
visualization tool of the CURENT Large-scale Testbed (LTB) that can be used for
large-scale power system closed-loop simulation. First, Distributed Messaging
Environment (DiME) implements an asynchronous shared workspace to enable
high-concurrent data exchange. Second, Another Grid Visualizer (AGVis) is
presented as a geovisualization tool that facilitates the visualization of
real-time power system simulation. Third, case studies show the use of DiME and
AGVis. The results demonstrate that, with the modular structure, the LTB is
capable of not only federal use for real-time, large-scale power system
simulation, but also independent use for customized power system research.
