Anup Nambiar

A Fully Coupled Wave-to-Wire Model of an Array of Wave Energy Converters

This paper describes a fully coupled, wave-to-wire time-domain model that can simulate the hydrodynamic, mechanical, and electrical response of an array of wave energy converters. Arrays of any configuration can be simulated to explore both the effects of the array on the electricity network and of network events on the devices within the array. State-space modeling of the hydrodynamic radiation forces enables fast and accurate prediction of the interacting response of multiple devices, including the effects of wave climate, control strategies, and network power flow. Case studies include the demonstration of the bidirectional interaction of the array and the network.

Quantification of voltage fluctuations caused by a wave farm connected to weak, rural electricity networks

This paper describes a wave-to-wire model of an array of wave energy converters developed in MATLAB/Simulink. The effects of connecting a 1MW wave farm to a weak, rural electricity network are investigated. Impacts of the wave farm on voltage quality are examined and both conventional and more intelligent control methods by which these impacts can be mitigated are discussed. The control methods compared are: constant voltage operation, constant power factor operation, On Load Tap Changing Transformer (OLTC) operation, automatic voltage and power factor controller (AVPFC) operation and fuzzy logic power factor controller operation. The applicability of these control methods are compared using certain indices - flicker severity index, voltage fluctuation index and global voltage regulation. Drawbacks of power factor control, voltage control and control using the OLTC transformer and the advantages of using more intelligent control methods, like the AVPFC or the fuzzy logic power factor controller, are established.

Modelling arrays of wave energy converters connected to weak rural electricity networks

This paper describes a modelling framework developed in Matlab/Simulink that has been used to study, analyse and improve the network integration of Wave Energy Converters (WECs). It presents and discusses a generic, time domain, resource-to-wire model that can be used to explore the effects of: increased device numbers, array size and physical positioning; and the adjustment of control parameters. The three-dimensional wave field is modelled as non-stationary, with statistical characteristics that are extracted from measured wave elevation time series to simulate increasingly realistic sea conditions. Each heaving buoy has high-pressure oil power take off with on-board energy storage, driving Doubly Fed Induction Generators (DFIGs). The results obtained from simulations using this model are used to demonstrate the overall effects of storage on real power production, and the effects of imaginary power control on network voltage profile. The opportunities for improved network integration are identified and discussed.

Network design tool for the optimal design of offshore ocean energy array networks

This paper presents a simulation tool for the design and analysis of offshore ocean energy array networks. The tool integrates a number of modules which are divided into two core functions: the automation of the cable laying algorithm and subsequent creation of the network model, and the other performing the power flow analysis. The results of the power flow analysis are used to inform the user of the levelised cost of energy of different network configurations. The tool is compatible with geographical information system (GIS) software to allow for easy integration within the array design, installation and operation and maintenance stages.