Gm Shafiullah

Survey of Wireless Communications Applications in the Railway Industry

Advances in information and communications technology have enabled the adoption of wireless communication techniques in all sectors for the transmission of information in all forms between any two points. Wireless communications and distributed computing have promoted the development of vehicle- monitoring systems to reduce the maintenance and inspection requirements of railway systems while maintaining safety and reliability. This paper surveys existing wireless techniques used in the railway industry for both communications and signalling purposes. Finally we present our work in progress on low-cost, low-power wireless sensor networking architecture to monitor the health of railway wagons attached to a moving locomotive.

Energy-Efficient Wireless MAC Protocols for Railway Monitoring Applications

Recent advances in wireless sensor networking (WSN) techniques have encouraged interest in the development of vehicle health monitoring (VHM) systems. These have the potential for use in the monitoring of railway signaling systems and rail tracks. Energy efficiency is one of the most important design factors for the WSNs as the typical sensor nodes are equipped with limited power batteries. In earlier research, an energy-efficient cluster-based adaptive time-division multiple-access (TDMA) medium-access-control (MAC) protocol, named EA-TDMA, has been developed by the authors for the purpose of communication between the sensors placed in a railway wagon. This paper proposes another new protocol, named E-BMA, which achieves even better energy efficiency for low and medium traffic by minimizing the idle time during the contention period. In addition to railway applications, the EA-TDMA and E-BMA protocols are suitable for generic wireless data communication purposes. Both analytical and simulation results for the energy consumption of TDMA, EA-TDMA, BMA, and E-BMA have been presented in this paper to demonstrate the superiority of the EA-TDMA and E-BMA protocols.

Energy-efficient TDMA MAC protocol for wireless sensor networks applications

The availability of low-powered and cheap microprocessors, radio frequency integrated circuits and the development of new wireless communication techniques, make the wireless sensor networks (WSN) one of todays most promising technologies. Minimizing energy consumption and maximizing the lifetime of the networks are key requirements in the design of sensor network applications. Optimally designed medium access control (MAC) and routing protocols minimize energy consumption and prolong the network life. In this study, we have investigated an energy-efficient adaptive TDMA (EA-TDMA) protocol for railway applications that used in communication between sensor nodes and the cluster-head (CH) placed in a railway wagon. This protocol is suitable for medium traffic applications and reduces energy consumption by shortening the idle period when devices have no data to transmit. We have developed an analytical model for EA-TDMA and compared its performance with conventional TDMA and bit-map-assisted (BMA) protocols.

A Survey of Energy-Efficient and QoS-Aware Routing Protocols for Wireless Sensor Networks

Recent developments in wireless communications have enabled the development of low-cost, low-power wireless sensor networks (WSN) with wide applicability, including environment and vehicle-health monitoring. Minimizing energy consumption and hence maximizing the life time of the network are key requirements in the design of optimum sensor networking protocols and algorithms. Several routing protocols with different objectives have already been proposed for energy-efficient WSN applications. This paper surveys a sample of existing energy-efficient cluster-based and QoS-aware routing protocols and highlights their key features, including strengths and weaknesses

Effect of Transition Metal Cations on Stability Enhancement for Molybdate-Based Hybrid Supercapacitor

The race for better electrochemical energy storage systems has prompted examination of the stability in the molybdate framework (MMoO4; M = Mn, Co, or Ni) based on a range of transition metal cations from both computational and experimental approaches. Molybdate materials synthesized with controlled nanoscale morphologies (such as nanorods, agglomerated nanostructures, and nanoneedles for Mn, Co, and Ni elements, respectively) have been used as a cathode in hybrid energy storage systems. The computational and experimental data confirms that the MnMoO4 crystallized in β-form with α-MnMoO4 type whereas Co and Ni cations crystallized in α-form with α-CoMoO4 type structure. Among the various transition metal cations studied, hybrid device comprising NiMoO4 vs activated carbon exhibited excellent electrochemical performance having the specific capacitance 82 F g-1 at a current density of 0.1 A g-1 but the cycling stability needed to be significantly improved. The specific capacitance of the NiMoO4 electrode material is shown to be directly related to the surface area of the electrode/electrolyte interface, but the CoMoO4 and MnMoO4 favored a bulk formation that could be suitable for structural stability. The useful insights from the electronic structure analysis and effective mass have been provided to demonstrate the role of cations in the molybdate structure and its influence in electrochemical energy storage. With improved cycling stability, NiMoO4 can be suitable for renewable energy storage. Overall, this study will enable the development of next generation molybdate materials with multiple cation substitution resulting in better cycling stability and higher specific capacitance.

Prospects of solar energy in Australia

Today, more than 80% of energy is produced from fossil fuels that pollute the air and surrounding environments each and every day, creating global warming. Therefore it is time to think about alternative sources of energy to build a climate friendly environment. In contrast to fossil fuels, renewable energy offers alternative sources of energy which are in general pollution free, unlimited, and environmentally sustainable. This paper presents a feasibility study undertaken to investigate the prospects of solar energy for the climate similar to Australia so as to further investigate the impacts of renewable energy sources in existing and future smart power systems. The monthly average global solar radiation has been collected for twenty-one locations in Australia from the National Aeronautics and Space Administration (NASA). Hybrid Optimisation Model for Electric Renewable (HOMER), and Renewable-energy and Energy-efficient Technologies (RETScreen) computer tools were used to perform comparative analysis of solar energy with diesel and hybrid systems. Initially, total net present cost (NPC), cost of energy (COE) and the renewable fraction (RF) were measured as performances metrics to compare the performances of different systems. For better optimisation, the model has been refined with a sensitivity analysis which explores performance variations due to solar irradiation and electricity prices. Finally, a statistical analysis was conducted to select the best potential places in Australia that produce maximum solar energy.

Voltage fluctuations in PV penetration on SWER networks — A case study for regional Australia

Penetration of solar energy is increasing rapidly in Australia over the last decade due to its availability and climate-friendly attributes. Solar energy is free from green house gas (GHG) emission and plays a key role in developing a sustainable power system for the future. However, the intermittent nature of solar energy creates a number of potential challenges in integrating large-scale photovoltaic (PV) with the grid. Voltage fluctuation, voltage management, harmonic distortion, demand management, and load rejection are the major potential issues concerning the application of photovoltaic in Single Wire Earth Return (SWER) network. This paper presents the impacts of varying PV penetration levels on different SWER networks. Of particular interest was the adverse affect on voltage instability of the network with varying PV penetration. Simulation results shows that voltage rises across the network would exceed regulatory standards with the high penetration of PV in SWER networks.

Reduction of power consumption in sensor network applications using machine learning techniques

Wireless sensor networking (WSN) and modern machine learning techniques have encouraged interest in the development of vehicle monitoring systems that ensure safe and secure operations of the rail vehicle. To make an energy-efficient WSN application, power consumption due to raw data collection and pre-processing needs to be kept to a minimum level. In this paper, an energy-efficient data acquisition method has investigated for WSN applications using modern machine learning techniques. In an existing system, four sensor nodes were placed in each railway wagon to collect data to develop a monitoring system for railways. In this system, three sensor nodes were placed in each wagon to collect the same data using popular regression algorithms, which reduces power consumption of the system. This study was conducted using six different regression algorithms with five different datasets. Finally the best suitable algorithm have suggested based on the performance metrics of the algorithms that include: correlation coefficient, root mean square error (RMSE), mean absolute error (MAE), root relative squared error (RRSE), relative absolute error (RAE) and computation complexity.

Participation of DFIG based wind energy system in load frequency control of interconnected multigeneration power system

Maintenance of system frequency within utility prescribed tolerance band was considered as exclusive responsibility of conventional power plants. Fluctuating power due to varying nature of wind inflict extra power imbalance to the power system leading to frequency deviation from the nominal value. This power generation needs to be balanced with other fast controllable generation sources. With increasing share of wind based energy generation on utility grid, provision of ancillary services from them is also gaining the status of necessity for total system reliability. Frequency regulation makes up as one of the category of these ancillary services for power system security management and quality reliability. Automatic generation control (AGC) is an important function for load frequency control (LFC). This paper addresses design aspects of LFC scheme for minimization of system frequency of interconnected multigeneration power systems in the presence of wind power. Integral of time multiplied by absolute errors (ITAE) has been applied to determine the optimal values for the controller gains of the system. It has been observed from simulations that control area having wind integrated with base load plant gives better AGC performance than the control area having wind integrated with peak load plant.

Experimental and simulation study of the impact of increased photovoltaic integration with the grid

The abundance, availability, and climate-friendly characteristics of solar photovoltaic (PV) energy encourage nations around the globe to adopt it to assist in overcoming global warming as well as build a sustainable society for the future. The intermittent nature of solar energy generation and the associated power electronic inverters with connected consumer loads creates a number of potential challenges in integrating large-scale PV into the grid that affects power quality of the distribution networks. This paper investigates the impacts of varying PV integration into the grid through experimental and simulation studies. Initially, several experiments were conducted with varying PV penetration and load conditions using the Renewable Energy Integration Facility at CSIRO, Newcastle, Australia. Later, a simulation model was developed that mimics the experimental facility used at CSIRO to investigate the adverse impacts on integrating large-scale PV into the grid using the power system simulation software PSS Sincal. Experimental and simulation analyses clearly indicate that integration of PV into the grid causes power quality issues such as voltage instability, harmonic injection, and low power factor into the networks and the level of these impacts increases with the increase of PV penetration.