Quantification of efficiency improvements from integration of battery energy storage systems and renewable energy sources into domestic distribution networks

Due to the increasing use of renewable, non-controllable energy generation systems energy storage systems (ESS) are seen as a necessary part of future power delivery systems. ESS have gained research interest and practical implementation over the past decade and this is expected to continue into the future. This is due to the economic and operational benefits for both network operators and customers, battery energy storage system (BESS) is used as the main focus of this research paper. This paper presents an analytical study of the benefits of deploying distributed BESS in an electrical distribution network (DN). The work explores the optimum location of installing BESS and its impact on the DN performance and possible future investment. This study provides a comparison between bulk energy storage installed at three different locations; medium voltage (MV) side and low voltage (LV) side of the distribution transformer (DT) and distributed energy storage at customers’ feeders. The performance of a typical UK DN is examined under different penetration levels of wind energy generation units and BESS. The results show that the minimum storage size is obtained when BESS is installed next to the DT. However, the power loss is reduced to its minimum when BESS and wind energy are both distributed at load busbars. The study demonstrates that BESS installation has improved the loss of life factor of the distribution transformer

Interaction Properties of Geogrids in Reinforced Soil Walls, Testing and Analysis.

The considerable development of the geosynthetics and their increasing use in soil reinforcement made it necessary to develop methods of measuring the interaction properties and modeling load transfer in reinforced soil structures. The current testing procedures demonstrate significant limitations related to the testing methodology and data interpretation. In order to address these limitations, a pull-out box and direct shear box were constructed. The design of these boxes overcomes most of theses limitations and provides the capability of conducting displacement-rate controlled tests for the evaluation of short-term behavior of the soil-reinforcement system, and load-controlled tests to evaluate their time-dependent performance. The accuracy of the testing facility was evaluated through comparison of test results with those provided by the manufacturers. The reproducibility of test results were evaluated through repetitive tests performed on the geogrids under the same testing parameters. A parametric study on the geogrids under different testing conditions (i.e. pull-out displacement-rate, confining pressures, soil compaction, soil density and boundary conditions) was conducted to evaluate the equipment sensitivity to the variations in testing conditions and to provide a data base for the evaluation of the effect of these parameters on the interface properties. A data analysis procedure was established to determine the interface properties and the confined material characteristics of the geogrid reinforcement. The applicability of the load-transfer model was evaluated through comparison between the interface parameters evaluated from pull-out tests with those measured directly from the tests performed in the large direct shear box. The interface properties and confined material characteristics of the geogrid reinforcement were utilized in a design model for the stability analysis of reinforced soil structures. This model is implemented in a computer program to calculate the forces in the reinforcements and to predict the failure plane. The maximum tension force at each reinforcement level and the inclination of failure surface can be predicted for different soil and reinforcement characteristics. In order to evaluate the design assumptions considered in this model, the predicted tension forces were compared with those measured in model and full-scale model walls and embankments of different soils and reinforcements

Point estimate method for voltage unbalance evaluation in residential distribution networks with high penetration of small wind turbines

Voltage unbalance (VU) in residential distribution networks (RDNs) is mainly caused by load unbalance in three phases, resulting from network configuration and load-variations. The increasing penetration of distributed generation devices, such as small wind turbines (SWTs), and their uneven distribution over the three phases have introduced difficulties in evaluating possible VU. This paper aims to provide a three-phase probabilistic power flow method, point estimate method to evaluate the VU. This method, considering the randomness of load switching in customers’ homes and time-variation in wind speed, is shown to be capable of providing a global picture of a network’s VU degree so that it can be used for fast evaluation. Applying the 2m + 1 scheme of the proposed method to a generic UK distribution network shows that a balanced SWT penetration over three phases reduces the VU of a RDN. Greater unbalance in SWT penetration results in higher voltage unbalance factor (VUF), and cause VUF in excess of the UK statutory limit of 1.3%

Women Representation in the Egyptian Parliament: Representation or Misrepresentation?

Egyptian women who played a pivotal role in both, January 25th and June 30th revolutions were rewarded by achieving the highest female representation in Egypt’s parliamentary history in the last 2015 elections (89-14.9%). This paper accesses women's representation/mis-representation in light of this increase in numbers .Results show that the implementation of a one-time quota, that not only seeks to include women but several unprotected sectors of the society, guaranteed positive outcomes but warns from a decline if not implemented for at least one more time ensuring the continuance of women empowerment. Keywords:-Women Representation – Egyptian 2015 parliamentary elections – Empowerment – Quota