# Novel Internet of Things Platform for In-Building Power Quality Submetering
## 1 Introduction  
Worldwide energy demand is constantly increasing. It is expected that global energy consumption will increase by more than a third in the period to 2035. Among all the energy demand, the building sector represents an average 20-40% of worldwide energy use [1]. This may become even more important as electricity demand is expected to rise in buildings, primarily due to electric heat pumps, and secondly due to the impact of electric vehicles charging facilities. Consequently, spreading the demand more evenly in time and better coordination with electricity availability could partially avoid the need for new infrastructure. Within the framework of Smart Electric Grid, substantial energy savings could be achieved by means of a Building Energy Management System (BEMS). Thus, the combination of direct load control (DLC) algorithms, during a Demand Response (DR) event, with detailed measurements and, furthermore, with the contextual energy reporting and analytics would drive to significant impact on reducing energy costs. However, the lack of end-load monitoring (or as we might call it: submetering) or recording energy consumption \"behind the meter\", e.g., at system-level or into individual appliances, have been an insurmountable barrier up to now. However, at some point in the future, submetering will be somewhat mandatory. In some cases, submetering in the multi-residential buildings can reduce the average electricity consumption by 34% for non-electrically heated buildings, and by 27% for electrically heated buildings [2]. However, submetering could be an important way not only to identify opportunities for operational efficiency but also to regulate demand, e.g., through virtual aggregation of different submeters, for a power system which progressively relies on variable and Distributed Energy Resources (DER). Power Quality (PQ) refers to deviations of the voltage or current waveform from the ideal single-frequency sine wave of constant amplitude and frequency. PQ deterioration is due to transient disturbances or events (voltage sags, voltage swells, impulses, etc.) and steady-state disturbances (harmonic distortion, unbalance, flicker). A consistent set of definitions and extensive overview to this important area can be found in [3]. Presently, PQ disturbances are of increasing concern due to present widespread use of power electronics equipment in industrial, commercial and residential buildings. White and brown goods are specifically sensitive to such imperfections. Among all categories of power disturbances, voltage sag (or dip), and momentary interruptions are the swords of Damocles of the automated industrial processes. Sag durations are subdivided in IEEE Std. 1159 [4] into three categories-instantaneous, momentary, and temporary. In distribution networks, power system faults are principally the origin of voltage sags. Fault occurrences elsewhere can create voltage sags that may disturb consumers to different extents depending on their position in the electrical network. Voltage sags affect a larger number of customers and, for some of them, extremely serious problems may be caused. Some examples are sensitive equipment that do not have adequate ride-through capabilities to withstand fluctuations in the electrical supply [5]. The need for line voltage regulation remains in order to meet demands for high industrial productivity. There are several conditioning solutions that have been developed to provide protection to PQ problems [6]. Correlating and categorizing (e.g., event type, magnitude, and duration) can be classified according to i.e., EN 50160 [7] or IEEE Std. 1159 [4] standards. However, only the standard EN 50160 establishes limits of the voltage supplied by the public distribution network. PQ events should be measured, depending on their deterministic or stochastic nature, by following the IEC 61000-4-30 [8] standard. In the other hand, steady-state signal variations such as harmonics are processed according to IEC 61000-4-7 [9].