NIST has been developing sensor technology for a new time domain-based protection scheme developed by the National Renewable Energy Laboratory. The signal processing technology underlying this project is a multi-point correlator that exploits the spatial distribution of transients in the inductive and capacitive components in a span of electrical conductor to recover a wave function called a Traveling Wave (Jafarian & Sanaye-Pasand, 2010). Since these transients are most pronounced at higher frequencies, they provide an effective means of detecting traveling waves that are generated during a fault. However, these traveling waves propagate at speeds in the order of  and are reflected from buses and other nodes. The algorithms that reconstruct the origin of these waves depend on accurate discrimination of the various reflected wave fronts requiring accurate time synchronization between various (up to a hundred) sensor sites. In addition, the correlator used to spatially resolve (or localize) the fault generating the traveling waves is sensitive to jitter in time stamps from the various sensor sites. Lastly, the intended scale of the sensor network used to provide this fault protection scheme can range from 100s of meters to 10s of kilometers.

In our talk, we will discuss the timing infrastructure we used during testing of our traveling wave-based fault protection scheme and we will present the timing challenges in scaling this solution to a ‘real’ electric distribution network. We will demonstrate that the requirements for this system push the limits on existing wide area synchronization technology with the hope of getting feedback from timing experts and spurring interest in a proof-of-concept infrastructure to support larger scale prototype deployment.