I. Santiago

Real-Time Monitoring System for a Utility-Scale Photovoltaic Power Plant.

There is, at present, considerable interest in the storage and dispatchability of photovoltaic (PV) energy, together with the need to manage power flows in real-time. This paper presents a new system, PV-on time, which has been developed to supervise the operating mode of a Grid-Connected Utility-Scale PV Power Plant in order to ensure the reliability and continuity of its supply. This system presents an architecture of acquisition devices, including wireless sensors distributed around the plant, which measure the required information. It is also equipped with a high-precision protocol for synchronizing all data acquisition equipment, something that is necessary for correctly establishing relationships among events in the plant. Moreover, a system for monitoring and supervising all of the distributed devices, as well as for the real-time treatment of all the registered information, is presented. Performances were analyzed in a 400 kW transformation center belonging to a 6.1 MW Utility-Scale PV Power Plant. In addition to monitoring the performance of all of the PV plant’s components and detecting any failures or deviations in production, this system enables users to control the power quality of the signal injected and the influence of the installation on the distribution grid.

Implementation of a real time monitoring system for a grid-connected PV park

The non-dispatchable, intermittent and unpredictable nature of photovoltaic energy has made its integration in power system very limited. This paper presents a system for monitoring, supervising and treatment of the information in real time applied to photovoltaic plants connected to the grid. Experimental results shows the usefulness of the system implemented for monitoring a grid-connected photovoltaic park production in real time, ensuring the synchronization of the magnitudes with high precision. This study demonstrates how the operation and maintenance of a photovoltaic plant and in general any renewable facility connected to the grid may be considerably improved by the use the proposed real time approach. With this functionality, the photovoltaic parks will become active parts of the grid, contributing to the massive integration of distributed generation in the smart grid.

Active occupation profiles in the residential sector in Spain as an indicator of energy consumption

Energy consumption in the residential sector represents a global average of around 30% of the total consumed in the country, so any measures that could help to reduce it, would have significant effects on the entire State. Thus, knowing the characteristics of consumption will provide important measures to reduce it, make more efficient the use of energy, and even set on advising for cheaper habits by focusing spending on slots where the fees may be lower. Residential electricity demand profile is highly correlated with timing of active occupancy. The objective of this study is to determine occupancy profiles in Spanish houses and some of its various regions, according to data from the Time Use Survey 2009-2010, conducted by the National Statistics Institute of Spain. With these data, it was implemented a model to generate artificial data and validate the occupation model achieved. The aim of this is to adopt strategies that could minimize energy consumption in the residential sector.

Simultaneous activities in the household and residential electricity demand in Spain

Recent research and policy studies on the low-carbon future highlight the importance of flexible electricity demand. This might be problematic particularly for residential electricity demand, which is related to simultaneous consumers’ practices in the household. This paper analyses issues of simultaneity in residential electricity demand in Spain. It makes use of the 2011 Spanish Time Use Survey data with comparisons from the previous Spanish Time Use Survey and the Harmonised European Time Use Surveys. Findings show that media activities are associated with the highest levels of continuity and simultaneity, particularly in the early and late parts of the evening during weekdays.

Performance monitoring of a solar photovoltaic power plant using an advanced real-time system

This paper presents a novel system which has been developed to supervise in real time the operation of a Grid-Connected Utility-Scale PV Power Plant in order to ensure a reliable and uninterruptible power supply. The system is composed of a complex acquisition architecture which measures the required information with a high temporal resolution and using a high-precision protocol for synchronizing all the devices, something strictly necessary for accurately establishing a relationship among all events taking place in the plant. Moreover, an advanced system for monitoring and supervising all the distributed devices, as well as for the real-time treatment of all the registered information is presented. This system does not only enable a better control over the performance of all the PV plants components by detecting any failures or deviations in production, but it also monitors the power quality of the injected signal and its influence on the distribution grid.

Smart community load matching using stochastic demand modeling and historical production data

The current upward trend of the residential energy demand and the high penetration of new renewable resources have changed the conception of the electrical grid. The centralized distribution scheme is currently moving forward to a distributed layout where the paradigm of Smart Energy Communities has emerged, meaning a set of households that share a Microgrid, have tied renewable production and can be either connected or disconnected from the main grid. In this context, due to the reduced dispatchability of the renewable generation, the planning of the installed PV power as well as the storage capacity is the cornerstone in order to achieve a high degree of both self-generation and self-consumption. However, the lack of detailed hourly or sub-hourly data makes it difficult. Therefore, this paper aims to present a high-resolution simulation method for evaluating the PV power and storage capacity requirements for a Smart Community based on a stochastic demand model and real PV production data, so the interplay between consumption and generation can be better understood.

Appliances in the residential sector: Economic impact of harmonic losses

In this work, the energy losses and the economic impact associated with the harmonic pollution of various frequently used appliances in the residential sector were estimated for Spanish dwellings. Most of the current residential devices, which contain power electronics (PE), produce harmonic emissions whose presence in the distribution system originates an increase of the losses in the wiring as well as a higher apparent power demand. The Time Use Survey (2009–10) conducted by the National Statistical Institute in Spain was used to obtain information about the activities taking place at the Spanish dwellings and directly related to the usage of some common residential appliances. Based on this information, as well as models of different types of household appliances, the active and non-active power annually demanded by this equipment in the Spanish residential sector were determined. Despite the negligible contribution of a single appliance, the aggregated effect of them, with a total annual energy demand greater than 19,000 GWh, can be significant enough to be considered in any energy efficiency program. Moreover, the research depicts that a reduction from 20% to 5% in the distribution system of the total harmonic distortion (THDi) can lead to a significant reduction of energy losses, as well as more than one thousand million Euros in energy savings. Single-phase power electronic loads, harmonics, economic impact, residential sector.

Influence of photovoltaic installation angles and geographical dispersion in the smoothing of photovoltaic fleet power fluctuations

The smoothing effects obtained by aggregating the production of several photovoltaic (PV) plants were analyzed in this paper, taking into account not only the grouped peak power or the distance between different PV plants, but also considering the different azimuth and tilt angles of the PV modules. The reduction in fluctuations, one of the main disadvantages of this energy source, will only have its effects on the distribution grid if the production of all grouped PV installations is injected in the same line of the network. Therefore, if it is not possible to include in the ensemble far away installations, with uncorrelated productions, a solution may be to use different installation angles in the grouped plants, in order to improve the reduction of fluctuations in the aggregated production injected to the grid.