The effect of net latency on the uncertainty in distributed measurement systems

These recent years have been characterized by the explosive growth of both the computational power of the small-size computers, and the PCs in particular, and their capability of interconnecting and exchanging data on a world-wide network. This development has involved almost all fields of the technical activity, including the measurements. The availability of a low-cost interconnection system, Internet, is pushing the evolution of the remote measurement systems, where the measurement results provided by in-field measurement systems were collected and stored by a central unit, towards the distributed measurement systems, where different systems, located in different places, share the same data in order to perform a measurement. The major drawback of these systems is the lack of synchronization of the shared data, due to the unpredictable net latency, which may affect the uncertainty of the result of the measurement in a quite significant way. This paper analyzes a distributed measurement system for electric power-quality measurements and shows how the effects of the possible net latency on the measurement uncertainty can be estimated.