A solution for improved simulation efficiency of a multi-domain marine power system model

Integrated Full Electric Propulsion (IFEP) marine power systems offer increased design flexibility and operational economy by supplying ship propulsion and service loads from a common electrical system. Predicting the behaviour of IFEP systems through simulation is important in reducing the design risk. However, the prevalence of power electronics and the potential for interaction between large electrical and mechanical systems introduce significant simulation challenges. This paper presents an integrated simulation tool, which brings together electrical, mechanical, thermal and hydrodynamic models, facilitating a holistic simulation capability. Approaches adopted for model validation and computational efficiency together with two case studies are discussed

Investigation of superconducting fault current limiter application in a power-dense marine electrical network

Power-dense, low-voltage marine electrical systems have the potential for extremely high fault currents. Limitation of fault currents is very attractive in a marine vessel, particularly in terms of switchgear cost, size, and weight, and reducing damage at the point of fault. This study shows that superconducting fault current limiters (SFCLs), even with relatively small impedances, are highly effective at reducing prospective fault currents. For the marine system investigated, various possible SFCL deployment strategies were found to be effective, particularly at the bus-tie location which can limit the fault current to approximately half the unrestricted value with an impedance of 0.1Ω. However, the chosen fault current limitation scheme will depend significantly on the vessel's electrical topology, the fault current contribution of each of the generators, and the properties of the SFCL device

Transmission use of system charges under future power system scenarios

If transmission charges are to reflect costs, they should be affected by the location of demand and generation. This paper describes the investment cost-related pricing (ICRP) methodology used to calculate transmission charges in Great Britain (GB), which is based on the marginal investment cost of additional demand or generation, using a dc load flow transport model. We apply this existing method to calculate charges for the Supergen FutureNet scenarios for 2020. This study highlights the sensitivities in charges for use of the transmission system arising from plausible demand and generation developments. The changes in tariffs will present financial challenges for system users in some areas. The objective of the work presented is to illustrate the sensitivity of the charges produced by this methodology to changes in demand, generation, and network topology rather than compare alternative pricing approaches. The conclusion drawn is that the ICRP system pricing method may be suitable in future years but only with some important issues investigated and resolved

Optimal flexible alternative current transmission system device allocation under system fluctuations due to demand and renewable generation

This study proposes two methods for the optimal placement of flexible alternative current transmission system (FACTS) devices considering variations in demand and renewable generation output. The basic optimisation technique utilised is the differential evolution algorithm and the objective is to minimise the cost of generation. The static performance of the FACTS device is considered here. Simulation shows that with renewable generation present in the network, the system state at peak demand is not always the most suitable state to use for the determination of the optimal FACTS allocation. From this, techniques based on the Monte Carlo simulation are proposed to determine the location for which the operation of FACTS device gives highest benefit in terms of saving cost of conventional generation. These techniques collectively are called renewable uncertainty-based optimal FACTS allocation techniques. This study shows the effectiveness of the techniques in the determination of the optimal FACTS placement for networks with a high penetration of renewable generation

Developing distributed generation penetration scenarios

The growth of distributed generation requires analysis based on realistic forecasts of future scenarios. This paper presents an original methodology that has been employed to develop penetration scenarios to support further research. The methodology combines top-down and bottom-up approaches to produce robust scenarios. The top-down approach is based on forecasts of total distributed generation at a national level. The bottom-up approach exploits expert opinion to determine the most likely developments under different conditions. The two approaches are combined according to the objectives of the analysis to be supported. The methodology offers a useful tool for scenario development and supports ongoing research in distributed generation

Coordinated protection, control and automation schemes for microgrids

This paper discusses coordinated protection, control and automation schemes for microgrids

Scenario-based analysis of the impact of marine energy development on Scotland's electricity network

This paper discussed scenario-based analysis of the impact of marine energy development on Scotland's electricity network. It was presented at the 6th European vave and tidal energy conference in 2005

Methods for reliability assessment in future power distribution networks

Distribution system reliability is an important issue in system planning, operation and maintenance. However, independent or network utility owned distributed energy resources (DER) can lead to both positive and negative impacts on distribution system reliability. Future distribution systems are likely to have many different mixes of DERs. Variable electricity generation sources such as some renewable energy technologies, energy storage devices and demand side management (DSM) will create greater uncertainties in network reliability. New reliability assessment methods are necessary to fully address these uncertainties and to provide an accurate evaluation of reliability for system planning and opera tional purposes. How existing analytical or probabilistic techniques could be adapted to this new challenge is not being researched at present. This paper presents a starting point of planned research in this area of reliability assessment for future distribution systems. The future reliability problem and possible assessment methods are fully discussed. Quantitative case studies are presented to demonstrate the possible application of reliability assessment methods. Conclusions are drawn from the future distribution reliability problem formulation and the case study results

Economic and technical evaluation of an energy storage system connected to an islanded distribution network

Increasing levels of distributed generation (DG) to support the reduction of carbon emissions requires innovative solutions and the investigation of the deployment of emerging technologies. Numerous electrically islanded power networks exist worldwide; some on geographic islands. The indigenous renewable resources of these locations bring a desire to maximise clean energy capture. The susceptibility of islanded networks to breaching intrinsic frequency and voltage constraints, through disturbances, is higher than that of interconnected systems. This paper sets out a general framework for assessing the introduction of a centrally sited, energy storage system (ESS) onto a typical islanded distribution network with load demand in the tens of MW range and with variable output renewable and conventional generation. The methodology is based on a techno-economic evaluation framework which permits the extent to which ESS can suppress network technical deviations to be quantitatively measured and the relationship between increased DG access and the ESS size to be examined. Based on the economic evaluation of the system operating costs and benefits, this paper concludes by stating the economic case for incorporating a MW sized ESS, on the case study network, is practical over a long period of time

Identification of long-term scenarios of electricity network development

This paper describes a process for generating scenarios of future electricity network development, and of technologies which might be applied in the electricity supply industry under different future circumstances. The process begins by considering scenarios at the most distant timeframe desired, and then working backwards to identify a set of shorterterm scenarios which interpolate between the long-term picture and current circumstances and trends. The paper discusses important factors which are taken into account in the initial longterm scenario generation, and in the identification of their corresponding shorter-term counterparts. The process is illustrated using its results in generating sets of scenarios, addressing the years 2020 and 2050, of future development of the electricity system in Great Britain. Examples of the resulting medium and long-term scenarios are described and illustrated pictorially