FPGA-based Protection System for Renewable Energy Sources Integrated Microgrids

Abstract:

Microgrids (MGs) is now achieving increasing attention from scholars all over the world. During last decade, the rapid development of Renewable Energy Sources (RESs) and power electronics technology bring another evolution to MGs, further decreasing the flue consumption and enhancing the energy efficiency. However, the introducing of RESs brings its uncertainty and irregularity into MGs simultaneously, leading to the fluctuation in MGs. In order to cope with the oscillation, Energy Storages (ESs) are employed to mitigate the fluctuation, but the life cycle and operations of ESs become additional potential risks. Besides, the operation of RESs and ESs depend on numerous converters, which may cause terrible harmonic pollution in MGs. Hence, the protection system is urgently required in modern MGs. Limited in power generated and size, island MGs are more likely to show weakness in coping with disturbance, so the proposed project take a residential MG (RMG) as the main case to analyse the dynamic characteristic of RESs integrated island MGs. The protection system and control strategy will be designed accordingly and be verified in a RMG and a Shipboard Microgrid (SMG).
By the proposed project, a protection system for MGs with hybrid Energy Generation System (EGS) and hybrid Energy Storage System (ESS) will be designed to prevent and handle the risks or accidents. Considering about the complexity of the structure of RESs integrated MGs and the computation burden of real-time control, FPGA-based controller would be introduced into the system to implement the real-time modification of the energy source utilization and evaluation of system healthy. The proposed scheme for MGs will be applied to practical MGs equipped with ESS and DGs such as RMGs and SMGs.
The project mainly contains two parts. Firstly, an optimized Energy Management System (EMS) aiming at enhancing the stability of MGs will be designed. The primary task of the EMS is mitigating the fluctuations of MGs, which will greatly improve the robustness of MGs and prevent a plenty of potential risks caused by overvoltage or under voltage failure of loads. The secondary task is scheduling the utilization of ESS and EGS to guarantee the power supply of MGs. Secondly, a real-time control strategy for potential risks or accidents will be designed to cope with abnormal conditions in MGs. A FPGA-based controller will be employed to control the generators and ESs to deal with the abnormal operation of high-power loads or uncertainty of RES.
In order to verify the feasibility of the proposed protection system, simulation in MATLAB will be carried out using simpower system, all the RESs, ESS and typical loads will be modelled, the control strategy will be designed in the simulation platform first. As for experimental verification, a Hardware in Loop (HIL) system will be established using real time control and monitoring platform (dSPACE) in IoT Laboratory to test the practical functions of the aforementioned protection system.


Funding: China Scholarship Council