Bruno Soares Moreira Cesar Borba

Modeling Distributed PV Market and its Impacts on Distribution System: A Brazilian Case Study

Nowadays, many countries are applying energy policies to promote Distributed Generation (DG). In Brazil, the National Electric Energy Agency (ANEEL) published the Normative Resolution 482/2012 in order to establish the general conditions for access of distributed generation for the grid and compensation mechanisms for the energy generated by the consumer. Among DG technologies, solar photovoltaic (PV) plays a major role due to advances in PV technology, combined with decreasing capital costs and subsidies. The intermittent renewable DG integration may cause impact on distribution power system and several studies have been carried out to analyze grid integration issues associated with PVDG penetration. However, in general, these studies consider penetration scenarios randomly generated or based on technical aspects, regardless economic characteristics of customers. Therefore, this paper proposes a methodology to assess the impact of DG on distribution system considering customer adoption scenarios. A real Brazilian case study is analyzed and the distribution system simulation is performed with the Open Distribution Simulator Software (OpenDSS).

Impact of photovoltaic integration on voltage variation of Brazilian secondary network distribution system

This paper aims to investigate the voltage variation on a typical network distribution in Brazil due to photovoltaic penetration. The perspectives for an increase of decentralized grid connected photovoltaic system in the next years are positive, due to the new regulatory framework in the country. A computational simulation was performed in MATLAB/SIMULINK using typical features of a Brazilian urban network. Simulations were performed with various load demand and PV penetration levels. We considered two different scenarios of a daily energy consumption. The first one considers a typical Brazilian load curve with a sharp peak around 7pm. The second scenario presents a flatter load curve that can be achieved assuming a smart grid concept. The results showed that for a typical Brazilian distribution grid, the photovoltaic system penetration could reach a percentage value of 30% without exceed the upper voltage limit. However, if a smarter and more efficient energy consumption is considered, the photovoltaic system penetration is increased to 40%.

Power factor metering system using Arduino

The power factor (PF) levels are established by each countrys national standards. In Brazil the lower power factor level allowed is 0.92. In order to monitor this quantity, the present paper uses Arduino to develop a PF metering system. It presents all the necessary theories concerning the calculus of the power factor itself, the programming logic applied to the data acquisition, and the details of the hardware components used in this system. In the end, two tests are conducted so that the meter accuracy can be evaluated. The results are compared with regulated measuring instruments.

Electricity Auction Simulation Platform for Learning Competitive Energy Markets

Electricity trading is an essential aspect in the business model for all players in the electricity industry. However, electricity differs from other commodities in some fundamental aspects: it cannot be stored, its demand and supply must be matched instantaneously, and generation and transmission are performed through a complex infrastructure system. These features make the electricity market environment very different from other commodities markets.

Voltage control analysis of photovoltaic inverters using a real Brazilian distribution network

The voltage control of distributed generators (DGs) is one of the main challenges the distribution networks are facing due to the remarkable increase of DG penetration in the last years. Regarding the photovoltaic (PV) systems, this issue can be accomplished locally through its inverters active and reactive power control capabilities. Thus, in order to investigate the impact of PV systems on the distribution network voltage, this article analyzes the penetration of PV DGs on a real Brazilian distribution grid with 1564 consumers, simulating the operational features of the inverters for voltage control. The simulations are carried out through Open Distribution System Simulator (OpenDSS). Consumers and region real technical and economic database as well as the applicable DGs regulatory policies are also considered on the simulations, in relation to the DGs penetration level. The results indicate Volt-Var control applied to PV systems has achieved an overall better result than the other controls strategies, especially on grid losses. Besides, the OpenDSS function Varfollowinverter applied to the Volt-Var control turns out as an alternative in relation to Volt-Var and Fixed Power Factor strategies concerning voltage improvement and losses minimization.

Optimal EV charging and discharging control considering dynamic pricing

EV penetration allows the bidirectional power flow between power grid and EV, called vehicle-to-grid (V2G). The V2G implementation requires different price signals, such as real-time pricing (RTP) and time-of-use pricing (TOU). This work investigates the smart EVs charging control problem at a distribution transformer level. In order to evaluate the peak shaving and the transformer load factor increasing due to coordinated V2G process, three EV penetration levels are evaluated: 30%, 60% and 100% of residential households with one EV. The charging and discharging of the battery is optimized to minimize the net electricity cost during a 24-hour period, with three different types of dynamic prices. The computational model was developed using the Matlab/Simulink and a linear programming technique is used. The results shows that coordinated charging control limits the peak demand elevation and provide peak shaving for substation and distribution transformers. The instantaneous RTP showed better results and TOU could shift the demand peak to another time of the day.

Maximum PV Penetration Under Voltage Constraints Considering Optimal Sizing of BESS on Brazilian Secondary Distribution Network

The Distributed Generation (DG) has substantially increased around the world and it is expected to play an important role in the future of power systems. Most of DG systems are composed by renewable energy sources, such as Photovoltaic (PV), which has an intermittent behavior, resulting in negative impacts on the distribution network, such as voltage fluctuation. In order to mitigate the voltage rise problem, this paper presents an optimal sizing of a Battery Energy Storage System (BESS) with an efficient charge and discharge strategy, as a way to increase PV penetration, without exceed voltage limits. MATLAB / Simulink is used to simulate a typical Brazilian residential secondary distribution system using actual photovoltaic data and residential load profile from Southeastern Brazil. The results show that the photovoltaic system penetration could reach 40% for a transformer operating at nominal load, without BESS. However, if a BESS is used, the PV penetration could be increased up to 80%. Moreover, it is showed that the BESS can provide an efficient peak shaving in the original load curve.

Technical and economic analysis of energy storage systems integration into the distribuition network with photovoltaic generation

The increase of distributed generation (DG), in a smart grid concept, has been motivated by various benefits in different areas such as economic, environmental, energy security, reliability and quality of electricity supply. However, the use of variable energy sources, as the solar photovoltaic generation, can lead to a series of local impacts, requiring new approaches and solutions for the electricity utilities. One of the possibilities is the association with an energy storage system, which allows the power system to operate in a stable and continuous condition, regardless of load fluctuations, reducing the variability of power generation. Therefore, this work aims to perform a case study in order to assess the technical and economic impact of the integration of energy storage system, composed by batteries, in the distribution system network, as a way to complement a photovoltaic distributed generator. The results show that this association is essential to improve the use of variable distributed photovoltaic generation and to provide a flatter load curve.