J.M. Ferreira de Jesus

A wind park reduced-order model using singular perturbations theory

Due to the increasing penetration of wind energy, it is necessary to possess design tools that are able to simulate the impact of these installations on electric utility grids. In order to provide a net contribution to this issue, a detailed wind park model has been developed and is briefly presented. However, the computational costs associated with the performance of such a detailed model in describing the behavior of a wind park composed by a considerable number of units may render its practical application very difficult. To overcome this problem, singular perturbations theory has been applied to reduce the order of the detailed wind park model, and therefore create the conditions for the development of a dynamic equivalent which is able to retain the relevant dynamics with respect to the existing AC power system. Validation results proving the ability of singular perturbations reduced order model to match the results provided by the detailed model are shown and commented upon.

Frequency control during transients in offshore wind parks using battery energy storage systems

ABSTRACT The main objective of this paper is to study the implementation of a battery energy storage system (BESS) in order to improve the dynamic behaviour of an offshore wind farm. Special attention is given to the frequency excursions limitation in the sequence of a fault on the onshore grid. This goal is accomplished by setting up a case study in which an offshore wind farm is connected to an onshore grid through a high voltage direct current line commutated converter (HVDC-LCC) link. The Power System Simulator for Engineering (PSS/E) simulation tool is used to implement the whole system, including the onshore and offshore grids and the load flow and dynamic models of the conventional generators, the wind turbine generators (WTGs), the HVDC-LCC link and the BESS. With the BESS out of service, some protective actions of the DC link lead to the uncontrolled frequency increase of the WTG, which are consequently tripped out. The BESS proves to be essential, as it allows the offshore wind farm to keep running by maintaining the frequency of the WTG at acceptable levels and therefore bringing the entire system to a steady state operating point.

Off-stream Pumped Storage Hydropower plant to increase renewable energy penetration in Santiago Island, Cape Verde

In order to reduce the high dependence on imported fuels and to meet the ongoing growth of electricity demand, Cape Verde government set the goal to increase renewable energy penetration in Santiago Island until 2020. To help maximize renewable energy penetration, an off-stream Pumped Storage Hydropower (PSH) plant will be installed in Santiago, in one of the following locations: Cha Goncalves, Mato Sancho and Ribeira dos Picos. This paper summarizes the studies carried out to find the optimal location and connection point of the PSH plant in Santiagos electricity network. This goal was achieved by assessing the impact of the PSH plant, in each location, on power system stability. The simulation tool PSS/E of Siemens was used to study the steady-state and dynamic behavior of the future (2020) Santiago MV grid. Different scenarios of demand and renewable resources were created. Each hydro unit of the PSH plant was modeled as an adjustable speed reversible turbine employing a DFIM. The results show that Santiagos grid with the PSH plant in Cha Goncalves is the one that has the best performance.

Integration of a Nuclear Power Plant in a Transmission Grid with a Large Penetration of Wind Generation

Abstract This paper addresses the integration of a Nuclear Power Plant (NPP) in a Transmission Grid in which the installed capacity of Wind Turbine Generators (WTG) represents an important share of the demand. The impact of the integration of the nuclear power is performed through both steady state and transient stability analysis of the grid. To perform these studies, particular care was taken in the models used both for the NPP and the WTG. The results of this study allowed some conclusions regarding the impact of both types of generation in the transient stability of the transmission grid and in the establishment of a methodology to perform this type of studies.