Mathematical Morphology-Based Artificial Technique for Renewable Power Application

This paper suggests a combined novel control strategy for DFIG based wind power systems(WPS)under both nonlinear and unbalanced load conditions.The combined control approach is designed by coordinating the machine side converter(MSC)and the load side converter(LSC)control approaches.The proposed MSC control approach is designed by using a model predictive control(MPC)approach to generate appropriate real and reactive power.The MSC controller selects an appropriate rotor voltage vector by using a minimized optimization cost function for the converter operation.It shows its superiority by eliminating the requirement of transformation,switching table,and the PWM techniques.The proposed MSC reduces the cost,complexity,and computational burden of the WPS.On the other hand,the LSC control approach is designed by using a mathematical morphological technique(MMT)for appropriate DC component extraction.Due to the appropriate DC-component extraction,the WPS can compensate the harmonics during both steady and dynamic states.Further,the LSC controller also provides active power filter operation even under the shutdown of WPS condition.To verify the applicability of coordinated control operation,the WPS-based microgrid system is tested under various test conditions.The proposed WPS is designed by using a MATLAB/Simulink software.

Comparative Study of the Thermal Comfort of Four Materials Type Used in the Construction of a Building

This research work consisted in making a comparative study of the thermal comfort of four materials types used in the construction of a building.A simulation of the building with the various materials on the KoZiBu software in reference and optimized situation was carried out.A study on the sensitive and air-conditioning loads as well as the curves of temperatures on a building of type F2 in situation of reference and in optimized situation was made on the one hand and the other hand a study on the same building without air-conditioning in reference and optimized situation.Finally,the analysis of the results favorizes the choice of the material having the best thermal comfort.The conclusions of these works show that the material that can give the best comfort and the most economics in terms of energy is the adobe which offers temperatures(301.40K or 28.40°C)and a good indoor thermal environment compared to BLT(blocks of cut laterite),BTC(blocks of compressed earth)and cinder block.Dwellings built with earthen materials offer a better indoor thermal environment than those built with modern construction materials,which are used more and more in the construction of houses in Burkina Faso.

The response of sedimentary record to catchment changes induced by human activities in the western intertidal flat of Yalu River Estuary,China

The response to the catchment changes of the sedimentary environment of the western intertidal flat of Yalu River Estuary was investigated by analyzing the vertical variations of the grain size of sediment cores,along with the hydrologic data and human activities in the catchment.The results demonstrated a stepwise decreasing trend for the variations of both the sediment load and water discharge into the sea,which could be divided into three stages as 1958–1970,1971–1990 and 1991–2009.Reservoir construction and the changes of catchment vegetation coverage turned out to be the two predominant contributors to the changes.There are four periods for the variation of the sensitive components of the sediment cores from 1940 to 2010,i.e.,1940–1950,1951–1980,1981–1990 and 1991–2010.The vertical distribution of grain size in the cores mainly varied with the changes of vegetation coverage in the catchment and reservoir construction from 1960 to 1980,whereas it varied depending on the intensity of water and soil erosion in the catchment from 1980 to 1990.Despite the further reduction of the water and sediment input into the sea from 1990 to 2009,this period was characterized by coarsening trends for the grain size of sediment in the estuarine intertidal flat and correspondingly,the significantly increased silt contents of the sensitive component.

Dependency of Electrical Demand of Bangladesh Power System on the Weather of the Country

The variation of electrical demand above its base value is its common characteristic. The weather dependent variation of demand, especially where the weather is severe in nature, requires a significant reserve margin of the generation system. The evaluation of the weather dependent component of the electric demand is the basic tool for the planning of the reserve margin. This paper evaluates the weather dependent portion of the load of BPS （Bangladesh power system）. The evaluation of the weather dependent portion of the demand is based on the EMD （empirical mode decomposition） technique.

Coordinated Active and Reactive Power Optimization Considering Load Characteristics for Active Distribution Network

Voltage sensitive loads are extremely susceptible to voltage fluctuations,resulting in power system safety issues and economic losses.Due to the load component of voltage sensitive loads being changed at different times,a voltage sensitive load model including the time characteristics is proposed.To improve the voltage distribution in the active distribution network(ADN),the linearized active and reactive power coordinated optimization model for minimizing the operational cost(including the fluctuating cost of sensitive loads)is established.Finally,the simulation on the IEEE 33-bus system demonstrates that the proposed control strategy can effectively stabilize the bus voltage of the sensitive load and reduce the operational costs of the ADN.

Performance improvement of complementary feeders using static transfer switch system

The performance of complementary feeders, running in parallel, can be significantly improved by installing static transfer switches （STSs） at critical locations. We develop the STS control logic, which transfers the critical load from the preferred feeder to the alternate feeder when a voltage sag or a fault occurs on the preferred feeder. A forced commutation technique is proposed and implemented to turn off the preferred feeders＇ thyristor, thus avoiding cross current to flow and minimizing the transfer time. Simulation results show that the forced commutation technique is more effective as compared to the recently proposed time delay technique for STS operation. Two different feeders, namely New Exchange, the preferred feeder, and Sector 1-10/2, the alternate feeder of Islamabad Electric Supply COmpany （IESCO）, Pakistan, have been selected for case studies. The software PSCAD/EMTDC professional package has been used for simulation.