A mathematical model for the virtual simulator of the power unit electrical part

The mathematical model is developed for a virtual training system (simulator) of the power unit electrical part operators of a thermal (nuclear) power plant. The model is used to simulating the main operating conditions of the power unit electrical part: generator idling, generator synchronization with the power system, excitation shifting from the main unit to the backup one and vice versa, switching in the power unit auxiliary system, and others. Furthermore, it has been implemented modelling some probable emergency conditions within a power plant: incomplete phase switching, damage to standard power unit equipment, synchronous oscillations, asynchronous mode, etc. The model of the power unit electrical part consists of two interacting software units: models of power equipment (turbine, generator with excitation systems, auxiliary system) and models of its control systems, automation, relay protection and signalling. The models are represented by the corresponding algebraic-differential equations that provide real-time mapping power unit processes at the operator’s request. The developed model uses optimal solving algebraic-differential equations to ensure the virtual process behaviour in real-time. In particular, the implicit Euler method is used to solve differential equations, which is stable when simulating processes in significant disturbances, such as accidental disconnection of the unit from the power system, tripping and energizing loads, generator excitation loss, etc.

Centroidal-polygon: a new modified Euler to improve speed of resistor-inductor circuit equation

Two types of first-order circuits are resistor-capacitor (RC) and resistorinductor (RL). This paper focuses on the RL circuit equation. The centroidalpolygon (CP) scheme will be tested using SCILAB 6.0 software. This new scheme (CP scheme) is addressed to improve the speed. For the first order circuit equation, the complexity is focused on the time complexity, which is speed of the time taken to complete the simulation in the electrical part. The CP scheme is compared with the previous studies, polygon (P) and harmonic-polygon (HP). The result shows that the CP scheme is less computational and an alternative to solve the first order circuit equation, and get the result quickly compared with the previous research.

Failure Prediction of Wind Turbine using Neural Network and Operation Signal

This paper deals with a novel prediction method for wind turbine by using neural network and operating data. As wind turbine transfer wind energy to electrical power energy, its structure has rotation part that capture wind energy, mechanical part, and electrical part that convert from mechanical rotation to electrical energy. Its working environmental situation is so bad like high mountain, sand desert, and offshore to capture good wind situation. Therefore, its control and monitoring should have high reliability for long terms during operation because its maintenance and repairing is very difficult and economically high cost. As wind turbine system is composed of three parts, there are many components that should be monitored to failure. This paper suggests neural network and operation data-based prediction method that can predict components' failure through data comparison and neural network's training function with easy expression of 'Yes' or 'No' for operator.

Continuous Passive Motion Machine for Elbow Rehabilitation

Continuous Passive Machines (CPM) facilitate patients in eliminating joint stiffness after surgery and lead to a faster and more efficient recovery. However, many previous CPM machined are mechanically complicated, expensive, and lack a user interface. This paper presents a new CPM machine for elbow flexion-extension and forearm pronation-supination. The machine is simple, low-cost, and equipped with Graphical User Interface (GUI). Its mechanism is designed so that it can be used on the left or right arms interchangeably. It is developed using aluminum, perspex, and steel rods. The electrical part of the machine consists of Arduino Uno to drive the motors and a potentiometer to measure the patients’ Range of Motion (ROM). The GUI for setting the exercise parameters and monitoring the patients’ progress has been developed using MATLAB software. The experimental results show that the machine has successfully provided the repetitive desired motions. The machine realizes elbow flexion-extension and forearm pronation-supination movements with 0ᵒ-135ᵒ and 0ᵒ-90ᵒ ranges of motion (ROM), respectively. The machine is also capable of increasing the elbow joint’s ROM by 5ᵒ increments for the therapy. The results show that the machine has the potential to be used in hospitals and rehabilitation centers.

Implementation of the control algorithm of the traction electric equipment

Currently, in various fields of science and technology, there is a fairly large number of methods for predicting reliability indicators, which differ in the set of tasks to be solved and the features of the mathematical apparatus used. When developing a methodology for calculating the reliability of an electric machine, one of the main stages is the development of a mathematical model, in which it is possible to take into account the factors, the impact of which directly affects the technical condition and the level of operational safety. Taking into account the disturbing influences during the implementation of the technological process is possible provided that the means of automation are used. The performed analysis of statistical data on traction motor failures made it possible to substantiate the advisability of warming up, since a significant number of electrical part failures occur in the autumn - winter - spring periods of time. This feature of the distribution of failures is to a certain extent due to the direct wetting of the insulation and a decrease in its dielectric strength. This process is associated with a sharp drop in external and internal temperatures when placing the locomotive at the depot, which contributes to the appearance of condensate on the insulation, its further destruction. The measure proposed in the article for warming up traction electrical equipment is aimed at an integer reduction in the failures of the electrical part of the electric motors under consideration.

SCIENTIFIC AND METHODOLOGICAL SUPPORT OF CREATION AND IMPROVEMENT OF TOWER STRUCTURES

In accordance with the decree of the President of the Russian Federation No. 899 of July 7, 2011, a list of critical technologies has been approved in our country, among which there are “technologies for creating energy-saving systems for the transportation, distribution and use of energy” [1]. First of all, we are talking here about electrical energy, and in the composition of these systems it is possible to distinguish not only the electrical part, but also the component associated with the construction of construction infrastructure. For the development of the economy in the technological area under consideration, appropriate scientific and methodological support is necessary, personnel who have mastered this support, then the formation of new or the use of existing relevant organizational structures in the ministries of construction and energy, in the design business and in production, and ultimately all of the above follows consolidate at the level of laws and standards. The place of the author's research in this development strategy is the development of scientific and methodological support for the creation of tower structures for the energy sector. The intermediate result of these studies is the monograph [2]. The topic was further developed in articles [3-16].

MONITORING OF ELECTRICAL AND THERMAL OUTPUT ENERGY OF SOLAR PHOTOELECTRICAL THERMAL INSTALLATION

This work describes the experimental model of integrated photoelectrical thermal (PVT) air collector with informative system for controlling and ruling based on microcomputer. A method of determining efficiency both electrical and thermal part of installation by the data of continuous monitoring parameters: output voltage, the charge current, the temperature of air on input and output of collector is proposed. The efficiency of electrical part (8%) and thermal part (50%) of PVT installation were determined for mart 2019.

Dynamics of a discontinuous coupled electro-mechanical system oscillator with strong irrational nonlinearities and with two outputs

The dynamics of the nonlinear electromechanical device, consisting of a mechanical part with two outputs and an electrical part which acts as the server is strongly investigated in the present work. The mechanical part consists of two nonlinear oscillators with strong irrational nonlinearities having smooth or discontinuous characteristics, where nonlinearity is just due to the inclination of springs, the geometric configuration, which are both elastically coupled. While the electrical part is the Rayleigh equation. By using the Lagrangian formulation, the model equations are established and used to investigate the equilibrium points and their stabilities. Nest by using the multiple time scales method, the analytical solutions are found both for the case of large amplitude and the weak amplitude, leading to interesting bifurcation sets of the equilibria by varying the control parameters, the inclination angles and driven frequency. Finally, numerical investigations of the exact equation of the system are used to justify the validity of analytical results and to find new phenomena such as chaotic impulses, chaotic bursting and the train of kink signal generations.

Estimating of the size of subsides for the use of hydrogen energy technologies for potential consumers

This article discusses the prospects for the use of hydrogen technologies in conjunction with renewable energy sources. A sim plified model of the power system of an isolated consumer using hydrogen technologies has been compiled. An experimental calculation of the electrical part of the system has been carried out. Based on the results obtained, conclusions are drawn about the further improvement of this model.

Structure and thermodynamics in the linear modified Poisson-Boltzmann theories in restricted primitive model electrolytes

Structure and thermodynamics in restricted primitive model electrolytes are examined using three recently developed versions of a linear form of the modified Poisson-Boltzmann equation. Analytical expressions for the osmotic coefficient and the electrical part of the mean activity coefficient are obtained and the results for the osmotic and the mean activity coefficients are compared with that from the more established mean spherical approximation, symmetric Poisson-Boltzmann, modified Poisson-Boltzmann theories, and available Monte Carlo simulation results. The linear theories predict the thermodynamics to a remarkable degree of accuracy relative to the simulations and are consistent with the mean spherical approximation and modified Poisson-Boltzmann results. The predicted structure in the form of the radial distribution functions and the mean electrostatic potential also compare well with the corresponding results from the formal theories. The excess internal energy and the electrical part of the mean activity coefficient are shown to be identical analytically for the mean spherical approximation and the linear modified Poisson-Boltzmann theories.