Modelling and Simulation of SCADA and PLC System for Power System Protection Laboratory

The protection of power system is an essential trait in a huge network to efficiently detect and isolate the sections undergoing faults or abnormal behaviour. The key components of a protection scheme include circuit breakers, relays, switchgears and fuses which employ communication from one station to another to achieve high-speed tripping. The automation of these components at the laboratory level using programmable logic controller (PLC) along with supervisory control and data acquisition (SCADA) system owns paramount importance for intelligent decision making, sensing, actuating, monitoring and maintaining the record in the host server. This paper discusses such a technique for conventional power system protection laboratory at a new level of development to promote a control system through PLC and SCADA. The control system has indication of over and under values of voltage, load and frequency, which can trigger malfunctioning of equipment and must be rectified. Furthermore, ground fault and inverse current indication are added to the system for monitoring and controlling purposes. The proposed system enhances the efficiency and safety of the expensive equipment and the personnel to the next level and also introduces new standards of automated protection schemes for modern technical institutes.

Device and Algorithm for Vehicle Detection and Traffic Intensity Analysis

To effectively manage the traffic flow in order to reduce traffic congestion, it is necessary to know the volumes and quantitative indicators of this flow. Various detection methods are known for detecting a vehicle in a lane, which, in turn, have their own advantages and disadvantages. To detect vehicles and analyse traffic intensity, the authors use a pulse coherent radar (PCR) sensor module. Testing of various modes of operation of the radar sensor was carried out to select the optimal mode for detecting vehicles. The paper describes a method for fixing vehicles of different sizes, filtering and separating the vehicle from the traffic flow. The developed vehicle detection device works in conjunction with signal traffic lights, through which traffic control takes place. The signal traffic lights, which have their own sensors and control units, communicate with each other via a radio channel; there is no need for cable laying. The system is designed to work on road maintenance sites. The paper describes the experimental data when testing on a separate section of the road. The experiment showed the advantage of traffic lights (cars passed the regulated traffic light faster) from the point of view of calculating the traffic flow over the normal traffic light operation. Reducing downtime in traffic jams, in turn, has a beneficial effect on the environmental situation, since at the moment internal combustion engines prevail in vehicles.

A Hybrid Routing Approach Using Two Searching Layers

This paper considers SUB_GOALs by using basic A* algorithm and Subgoal Graphs in a hybrid approach to execute optimal route. SUB_GOALs identified with pre-searching from basic A* at break points and Subgoal Graphs at corners of obstacles are added to SUB_TABLE to expedite the final searching in the hybrid approach. Map to work on is divided to subregions with decision-making process by using line-of-sight to avoid redundant searching. In the final searching layer, all feasible SUB_GOALs gained from decision-making process in the same subregion are connected to find final solutions of routes. Solutions achieved in the divided subregions are evaluated and combined to discover the final optimal route. The proposed hybrid approach is applied to three different scenarios in various dimensions of maps. In these three scenarios, the shortest route without hitting obstacles is calculated as 46.67, 57.76 and 124.7 units, respectively, and compared with other search algorithms. Simulation results of route planning are demonstrated to exhibit the effectiveness of the proposed hybrid approach.

Reduction of Mutual Coupling in UWB/MIMO Antenna Using Stub Loading Technique

The research presents mutual coupling reduction between UWB-MIMO antenna elements using stub loading technique. The proposed 2 × 2 UWB antenna geometry consists of two circular-shaped monopole radiators with a partial ground for perfect impedance matching. Stubs of 20 mm × 0.2 mm are inserted between the two antenna elements in the ground plane to improve the isolation. The decoupling stub leads to a mutual coupling reduction of less than 20 dB. The farfield measurement at a selected frequency of 10 GHz confirms an omnidirectional radiation pattern. Different MIMO antenna metric such as channel capacity loss (CCL), mean effective gain (MEG), total active reflection coefficient (TARC), envelope correlation coefficient (ECC), and surface current are presented. Details of the design considerations and the simulation and measurement results are presented and discussed. The proposed MIMO antenna array can be well suited for UWB applications.

Improvement of Pilot Symbol Orthogonal Sequences in 2×2 to 4×4 MIMO Wireless Communication Systems with Channel State Estimation

MIMO wireless communication systems with channel state estimation, in which 2 to 4 transmit-receive antenna pairs are employed, are simulated. The channel estimation is fulfilled by the orthogonal pilot signal approach, where the Walsh Hadamard-ordered sequences are commonly used for piloting. The signal is modulated by applying the quaternary phase shift keying method. Maximum 250 000 packets are transmitted through flat-fading Rayleigh channels, to which white Gaussian noise is added. Based on simulating 10 subcases of the frame length and number of pilot symbols per frame, it is ascertained that pilot symbol orthogonal sequences in 2×2 to 4×4 MIMO systems can be improved by substituting Walsh functions with partially unsymmetrical binary functions constituting the eight known orthogonal bases. The benefit is that the bit-error rate is substantially decreased, especially for 2×2 MIMO systems. Considering three cases of the pilot signal de-orthogonalization caused by two indefinite and definite pilot sequence symbol errors, the relative decrement varies from 0.123 % to 14.7 %. However, the decrement becomes less significant as the number of transmit-receive antenna pairs is increased.

A New Quasi Open Loop Synchronization Technique for Grid-Connected Applications

This paper presents an effective quasi open-loop (QOLS) synchronization technique for grid -connected power converters that is organized in two different blocks. The first block is a new flexible technique for extracting the positive and negative sequence voltage under unbalanced and distorted conditions. It is a decoupled double self-tuning filter (DD-STF) or multiple self-tuning filters (M-STF) according to the conditions. The main advantages of this technique are its simple structure and the fact of being able to work under highly distorted conditions. Each harmonic is separately treated and this allows for selective compensation in active filter applications. The second block is the frequency detector; we propose a neural approach based on an ADALINE for online adaptation of the cut-off frequency of the DD-STF and M-STF considering a possible variation in the main frequency. The main advantage of this method is its immunity to the voltage signal amplitude and phase. In order to improve the performance of the frequency estimation under distorted source voltage, a pre-filtering stage is introduced. Experimental tests validate the proposed method and illustrate all its interesting features. Results show high performance and robustness of the method under low voltage ride through.

Increasing the Piezoactivity of Manufactured Composite Piezoceramic Transformers by Combining the Processes of Soldering and Polarization

The article is devoted to solving the problem of ensuring high piezoactivity of composite piezoceramic transformers, in which the component parts are connected by soldering. The existing connection features have been analysed for the elements of composite piezoceramic transformers and the results have shown that during soldering the piezoceramic elements are exposed to thermal shock leading to depolarization of piezoceramics and deterioration of its piezoelectric properties. Diminution of temperature depolarizing effect is possible using low-temperature solders with a high tin content. However, in this case, the diffusion process of the electrode material of the piezoelectric element into the solder increases and the mechanical connection strength decreases. To eliminate these negative phenomena and solve the problem, a new method has been developed for connecting elements of composite piezoceramic transformers by soldering, where a polarizing voltage is applied to the composite piezoceramic transformer when heating and cooling, which prevents depolarization of the domain structure of piezoceramic elements. At the same time, high temperature ensures that polarization is carried out at lower values of the electric tension, and a more mobile domain structure after polarization has a lower level of coercive forces and, accordingly, a greater stability of parameters ov er time. Experimental verification has shown that the relative resonance gap increases by 6 % with a decrease in the dispersion of this value by 12 %, which indicates an increase in piezoactivity and stability of the characteristics of composite piezoceramic transformers manufactured using the solution above.

Square Slot Antenna for Wide Circularly Polarized Bandwidth and Axial Ratio Beamwidth

The article proposes design investigation and experimental results of a coplanar waveguide (CPW) fed square slot antenna that gives wideband circular polarization. This circular polarization characteristic is achieved by embedding a square shape stub to left bottom corner and an L-shaped strip to the right upper corner of the slot. A high impedance bandwidth of 87.8 % (3.6–9.0 GHz), a wide axial ratio bandwidth of 73.05 % (4.2–9.0 GHz) and wide 3-dB axial ratio beamwidth of 90° in the entire frequency range of interest are achieved with this antenna structure. To improve the 3-dB axial ratio bandwidth, three slots (two horizontal and one vertical) are scratched at the exterior periphery of the ground plane. These perturbation assemblies are accountable to excite orthogonal modes and help increase an axial ratio bandwidth. The designed antenna displays the constant and steady radiation patterns in the complete frequency range of concern. The overall dimension of the presented compact antenna is 0.24λ × 0.24λ × 0.01λ.

Data Processing in the Pilot Training Process on the Integrated Aircraft Simulator

Flight safety is an integral part of air transportation. Flight accidents are highly unlikely to appear but most of them are caused by the human factor. The aircrew training system for abnormal operations relies on integrated aircraft simulator-based exercises. Crew needs to be trained not to degrade piloting technique quality when facing increased psychophysiological tension. Therefore, methods evaluating the characteristics of ergatic aircraft control systems, warning systems for deterioration due to failures in avionics systems, piloting technique quality, and abnormal operation algorithms are necessary. An analysis of the bank angle has revealed that there are hidden increased tension manifestations in the human operator expressed in the transition of the flight parameter variation from a stationary random process to deterministic fluctuations in the form of a sinusoid. The goal of the research is to increase the efficiency of pilots’ training using integrated aircraft simulators based on the design and implementation of statistical data processing algorithms. To achieve the goal of the research, two algorithms for detecting deterministic fluctuations based on the Neyman-Pearson criterion and the optimal Bayesian criterion are developed. The presented algorithms can be used in the integrated simulator software to automate the decision-making process on piloting quality.

Wind Speed Distribution Direct Approximation by Accumulative Statistics of Measurements and Root-Mean-Square Deviation Control

In order to accurately estimate wind farm output and subsequently optimise it, a method of wind speed distribution approximation is suggested. The method is based on period-by-period accumulation of wind speed measurements, transforming them into empirical probabilities, and observing the moving approximation to the expected power produced by the wind turbine or entire wind farm. A year is a minimal term during which wind statistics are to be accumulated. The sufficient validity and reliability of the wind speed distribution approximation is supported by controlling root -mean-square deviations and maximal absolute deviations with respect to the moving average of the expected power. The approximation quality can be regulated by adjusting constants defining the requirements to the moving deviations.