Mott MacDonald

About: Mott MacDonald is a company organization based out in London, United Kingdom. It is known for research contribution in the topics: Electric power system & Wind power. The organization has 586 authors who have published 529 publications receiving 9801 citations. The organization is also known as: Mott MacDonald Group & MMD.

Value of Wind Power at Different Locations in the Grid

Abstract: Availability of wind energy which differs across locations primarily determines the appropriate location for installing windfarms. However, the grid location of windfarms must always be considered in an attempt to accurately quantify the benefits which can be achieved from windfarms during their lifetime operation to the supply network. The value of wind power is significantly affected by their penetration and concentration, and is further affected by their location within a network. This is because the location and penetration level of wind generation will result in a significant impact on power-flow distribution across the network. The objective of this paper is to measure the impact of grid location of windfarms on economic and operational parameters of a power system in the lifetime of a windfarm project. This paper first develops an assessment tool to quantify the economic and operational impact of wind power in the grid. This is followed by developing different scenarios in which different penetrations of wind power are installed at different locations in the grid, and it shows how the value of wind power is affected by location and network constraints.

Wet winter pore pressures in railway embankments

Abstract: This paper demonstrates the influence of extreme wet winter weather on pore water pressures within clay fill railway embankments, using field monitoring data and numerical modelling. Piezometer readings taken across the London Underground Ltd network following the wet winter of 2000/2001 were examined, and showed occurrences of hydrostatic pore water pressure within embankments but also many readings below this. A correlation was found between the maximum pore water pressures and the permeability of the embankment foundation soil, with high permeability foundation soils (of Chalk or river terrace deposits) providing underdrainage and maintaining low pore water pressures within the overlying clay embankment fill. Numerical modelling of transient water flow in response to a climate boundary condition supports this conclusion and has been used to demonstrate the influence of clay fill and underlying foundation permeability on transient pore water pressures during extreme (c. 1 in 100 year) and intermediate (c. 1 in 10 year) wet winter rainfall. For clay founded embankments, extreme wet winter conditions increased pore water pressures significantly compared with an intermediate winter, while for embankments underlain by a permeable stratum pore water pressures were less sensitive to the extreme winter rainfall.

Reliability assessment of water distribution systems with statistical entropy and other surrogate measures

Abstract: There is ever increasing commercial and regulatory pressure to minimise the cost of water distribution networks even as the demand for them keeps on growing. But cost minimizing is only one of the demands placed on network design. Satisfactory networks are required to operate above a minimum level even if they experience failure of components. Reliable hydraulic performance can be achieved if sufficient redundancy is built in the network. This has given rise to various water distribution system optimization methods including genetic algorithms and other evolutionary computing methods. Evolutionary computing approaches frequently assess the suitability of enormous numbers of potential solutions for which the calculation of accurate reliability measures could be computationally prohibitive. Therefore, surrogate reliability measures are frequently used to ease the computational burden. The aim of this paper is to assess the correlation of surrogate reliability measures in relation to more accurate measures. The surrogate measures studied are statistical entropy, network resilience, resilience index and modified resilience index. The networks were simulated with the prototype software PRAAWDS that produces more realistic results for pressure-deficient water distribution systems. Statistical entropy outperformed resilience index in this study. The results also demonstrate there is a strong correlation between entropy and failure tolerance.

Policy versus ground reality: secondary English language assessment system in Bangladesh

Abstract: Any policy reform in education is highly effective when it is planned and implemented ‘holistically’ and yet, it is the most challenging way forward. Many countries in Asia have reformed their English language policies and syllabi in the last two decades due to the increasing value of the language worldwide. Motivated by a ‘communicative approach’ to English language teaching, Bangladesh was one of the countries that launched such a reform in the 1990s. However, this reform has been criticised for imposing the changes on teachers without preparing them sufficiently. More importantly, there is limited evidence as to how much the secondary English language assessment system is aligned with the changes introduced in the curriculum. In order to explore this gap, a medium-scale study was conducted in 38 secondary schools in Bangladesh, following a mixed methods approach. The findings highlighted a ‘mismatch’ between the intended English language learning outcomes and current assessment practices, including the...

Service Restoration of Distribution Networks Considering Switching Operation Costs and Actual Status of the Switching Equipment

Abstract: Minimization of the de-energized consumers load and reduction of the service restoration costs are considered in the proposed heuristic graph-based approach for finding the solution of the service restoration in distributed networks. The approach is based on the logic of the modified Prim's algorithm that finds the minimum spanning trees (i.e., a forest). Operation costs including an actual status (“open” or “close”) of the switching equipment in a de-energized area is represented by the switching cost coefficients. The cost coefficients are assigned to all branches in a de-energized area. The switching action is performed by switching equipment with minimal switching costs coefficient in each iteration of the algorithm. The results confirm that the service restoration costs are decreased by the consideration of the actual status of the switching equipment.