Analysis of Electrical Loads and Strategies for Increasing Self-Consumption with BIPV Case study : Skarpnes Zero-Energy House

Master's thesis Renewable Energy ENE500 - University of Agder 2017At Skarpnes village (Southern Norway), the houses as zero energy buildings (ZEB) are installed with Building Integrated Photovoltaic (BIPV) systems, and these houses are not containing smart control of equipments. The aim of such buildings is that the amount of electrical energy produced is the same as that consumed in the buildings on an annual basis. In this thesis, the main objective is to analyse the methods for increasing self -consumption in BIPV, by minimizing the cost of purchasing electricity from the grid at time with no PV production, and maximizing the utilization of solar PV generated power, which reduces the power sold back to the grid. To achieve this, two methods for increasing self-consumption, namely demand side management (DSM) and energy storage using domestic hot water (DHW) tank were analyzed. Maximizing self-consumption of residential PV systems is profitable, because the sale cost of exported power to the grid is lower than that of importing power from the grid. To achieve high self- consumption, shiftable loads (e.g. heat pump) are controlled so that solar PV energy utilization especially at time with high solar irradiation can be maximized. The results show that, load shifting play an important role in minimizing the cost of imported energy, for example in May, by storing the excess PV production through DHW tank to be used in the evening or morning the following day. By considrering some selected clear days in six months, this excess PV energy boosted water from 40 0 C to 90 o C, (corresponding to the set limits for minimum and maximum temperature) without assistance from the grid distribution network. Supply and demand cover factors were used to determine when the loads in houses are covered by PV production or not. Based on the available dataset, it has been found that in December 2015 and May 2016, 3.3 % and 56.7 % of demand respectively is covered by solar PV. Loss of load probability (LOLP) is used to analyze the time where load demand is not covered by PV production at desired reliability level. The results of this research are important in implementation of DSM techniques for economic analysis in BIPV systems. Also, the use of excess PV energy storage through DHW tank minimizes the energy exchange between BIPV and the grid. The results of this thesis will contribute further to the investigation of self- consumption analysis in the BIPV systems, by maximizing energy utilization in the BIPV systems. Keywords: BIPV, PV production, electric loads, self-consumption, cover factors, Load-shifting, heat pump, domestic hot water storag

Fault Detecting and Isolating Schemes in a Low-Voltage DC Microgrid Network from a Remote Village

Fault detection and isolation are important tasks to improve the protection system of low voltage direct current (LVDC) networks. Nowadays, there are challenges related to the protection strategies in the LVDC systems. In this paper, two proposed methods for fault detection and isolation of the faulty segment through the line and bus voltage measurement were discussed. The impacts of grid fault current and the characteristics of protective devices under pre-fault normal, under-fault, and post-fault conditions were also discussed. It was found that within a short time after fault occurrence in the network, this fault was quickly detected and the faulty line segment was efficiently isolated from the grid, where this grid was restored to its normal operating conditions. For analysing the fault occurrence and its isolation, two algorithms with their corresponding MATLAB/SIMULINK platforms were developed. The findings of this paper showed that the proposed methods would be used for microgrid protection by successfully resolving the fault detection and grid restoration problems in the LVDC microgrids, especially in rural villages