# Dynamic Voltage Optimization Based on In-Band Sensors and Machine Learning
## 8 Prototype Implementation and Results
### Phase Disambiguation  
One of the most fundamental operations associated with DCP/UCP comparison and registration is disambiguation of per-phase data. As current disturbances propagate through the distribution grid, towards the substation, the multi-phase nature of the distribution infrastructure provides fertile ground for cross-talk, as described in detail in Section 5.2. Because of the nature of the distribution grid, even though anomalies will only occur in a single phase of the downstream network, versions of the anomalies will show up in all phases of the feeder where they occurred. The anomalies may have some combination of phase shifts and amplitude distortions, and often have other anomalies intertwined. This is mainly due to cross-talk in the core of the several transformers that are in the path. As a result, disambiguation of per-phase data via UCP profiles combined with geospatial registration associated with the out-of-band DCP profile can be of substantial value for the service provider. The correlation between phases and geospatial registration of a specific distribution phase with a specific meter (or set of meters) provides real-time situational awareness of the physical construction of the distribution infrastructure. As described previously, this \"as modified\" information can result in operational insights related to natural disasters as well as operational efficiencies related to phase balancing. In testing of our prototype system, we achieved over 99% accuracy in phase disambiguation with current disturbances that were \"large enough\" at the emulated meter to remain detectable even after passing through several transformers en route to the substation feeder breakers. Research is ongoing to determine which dimensions of \"detectability\" are most important in this process as well as the operational parameters of each dimension. The importance of this process is described graphically via Figures 8 and 9, which are the results of a prototype test of the approach described in this paper. In the prototype test, a complex current disturbance or \"DCP\" was introduced into a conventional 120 Vrms outlet using a programmablecurrent source, as previously indicated. The outlet was serviced by a single phase (Phase A) via a split-phase lateral derived from a 13 kV, three-phase feeder (Phases A, B, C). Figure 8 shows the flow of current on the feeder in the form of a spectrogram, which is a convenient visualization of the time-varying magnitude of spectral activity. The horizontal axis of the spectrogram is \"time\" and the vertical axis is \"frequency.\" The spectrogram shows the set of magnitude spectra for sequential, overlapping frames of acquired data, arranged in time sequence and viewed \"from above.\" In the figures, green is \"low magnitude\" and dark red is \"high magnitude.\" The spectrogram contains data from the UCP which corresponds to the DCP as it was presented in real time to Phase A of the feeder at the substation, after transiting the distribution grid from the low-voltage outlet to the high-voltage feeder at the substation. The figure clearly shows the fundamental at 60 Hz as a dark red, horizontal stripe. Similarly, the figure shows the odd harmonics of the fundamental at frequencies from 180 Hz (3 rd harmonic) to 1500 Hz (25 th harmonic) as horizontal stripes with shades of orange which vary as their magnitudes change with frequency. The DCP is evident in Figure 8 as a complex sequence of frequency-shifted and amplitude-modulated tones between 1020 Hz (17 th harmonic) and 1140 Hz (19 th harmonic). Even though the DCP was introduced into Phase A, Figure 9 clearly shows cross-talk between phases, which has previously been described in detail in Section 5.2. The cross-talk is produced between phases as the DCP disturbance transits the distribution network towards the substation. Figure 9 contains bandpass-filtered spectrograms for Phase A (bottom), Phase B (middle), and Phase C (top). The DCP is clearly present in all three phases.