Testing Algorithms for Controlling the Distributed Power Supply System of a Railway Signal Box

Purpose. To analyze the technical and economic indicators of the use of wind and photovoltaic stations in the power supply systems of non-traction consumers of railway power grids. The research methodology is based on modern methods of computational mathematics, statistics and information analysis using modern computer technology. Findings. The authors analyze the current prerequisites for the use of electricity generated from renewable sources (wind and photovoltaic stations) to supply non-traction consumers of railway power grids. The authors note that for reliable power supply to non-traction consumers in the presence of accidental wind flow or intensity of solar radiation, the capacity of wind and photovoltaic plants will need to be significantly overestimated, which leads to a significant increase in capital costs for construction. The paper presents examples of implementation of options for the construction of the above wind and photovoltaic stations for the variable nature of wind speed and intensity of solar radiation for specific regions of Ukraine (Vasylivka, Zaporizhia region). The authors present variants of the basic schemes of wind, solar and combined electric power supply systems for non-traction consumers. Information on technical and economic indicators of the most common domestic photo modules and wind turbines on the Ukrainian market is provided. The originality of the work is reflected in the examples of the introduction of options for the construction of wind and photovoltaic stations for the variable nature of wind speed and intensity of solar radiation for specific regions of Ukraine. Practical implications. The above calculation of the cost of the required number of power sources at wind, solar and combined power plants helps to choose the least expensive option for the introduction of renewable energy sources for non-traction consumers of railway networks. Keywords: renewable energy sources, photovoltaic installation, railway power supply networks, non-traction consumers of railway power grids, electricity production, solar radiation intensity, wind flow rate, capital expenditures.

Climate change, limited fossil fuel availability and the dependency on energy carrier imports lead the European Union to the formulation of an energy policy for Europe. The EU sets the following criteria for its future energy supply: sustainability, security of supply and competitiveness. Considering the carbon dioxide emissions of fossil fuels and the unsolved problem of the ultimate disposal of radioactive waste, only renewable energy can currently be considered sustainable if applied in a socially acceptable way and in accordance with nature conservation. The use of renewable energy can also reduce the dependency on energy carrier imports. Contrary to fossil fuels, renewable energy will become cheaper in the future due to technological learning. The main disadvantage of some renewable energy resources is their fluctuating availability. Adaptation of the energy supply system must take place especially in the power sector in order to reliably cover fluctuating demand with fluctuating resources at any time. In this work, the energy system model ‘REMix’ (Renewable Energy Mix for Sustainable Electricity Supply) is developed. It uses data on the availability of renewable energy across Europe and North Africa (EUNA) to dimension low-cost power supply structures for the EUNA-region, or parts of it, under specific conditions, such as specified shares of renewable energy in the power supply or specified national self-supply shares. The model takes into account the costs of generation technologies, transmission lines and storage units, and finds a combination of these technologies and their geographic locations that is least-cost under the given assumptions. A geographic information system was used for the analysis of the installable capacities and power generation potentials of typical technologies for harnessing renewable energy resources. This analysis is described and the potentials of solar PV, solar CSP, wind onshore and wind offshore, biomass, hydro and geothermal power plants are shown in tables and maps. The data are used as input into a linear programming energy system model which uses them as constraints on the power supply system to be dimensioned. The model, its sensitivity to input parameter variations and a test application are described. The findings confirm the basic findings of other work in this field: transmission lines can be a crucial element of a low-cost, renewable-energy-based electricity supply because they enable balancing effects in a large grid and the use of the highest quality resources even in remote areas, such as deserts or at sea. However, the international cooperation that is necessary to reach the cost-minimum for a given supply task may not be reached by politics or resulting dependencies may be opposed to political goals. Therefore, REMix was built such that countries can be examined individually and the influence of different parameters on their energy supply costs and structure can be investigated. In the test model application, power supply systems for 36 regions in Europe and North Africa, almost all individual countries, are designed with REMix as island grids on the one hand and on the other hand as a network without transmission restrictions (other than the costs of the transmission lines). The model shows that in certain regions the island grid electricity costs can be much higher than, only a little higher than, or even lower than the electricity costs in the network, under the given technological and economic assumptions. The sensitivity to parameter variations is shown to be high; the results of the test application must therefore be considered one example of a technically feasible and efficient supply system but cannot claim to be least-cost in general.

Reliability evaluation of an aggregate battery energy storage system in microgrids under dynamic operation

To solve the problems of high functional requirement, complex structure and poor versatility of manned spacecraft power supply and distribution ground test equipment, a modular universal ground power supply system (PSS) is designed. The functions of the system cover the functions of wire instruction opening, parameter measurement and state detection of the interface between the manned spacecraft and the ground equipment, and realize the universal and extensible configuration. This paper provides a general architecture design method for complex manned spacecraft power supply and distribution ground test system.

Sizing optimization research considering mass effect of hybrid energy storage system in electric vehicles

The existing definition of state of charge (SOC) cannot calculate under the circumstance of variable current or long-time heavy load discharge. Accordingly, it is necessary to propose a SOC definition based on energy theory. SOC is divided into static SOCs and dynamic SOCd to be applied the calculation of SOC in varied cases of energy storage battery. On this basis, considering the stored energy during the operation process is reduced constantly and the load power changes, dynamic SOCd estimation method is proposed. On a basis of experimental data on batteries carrying varied power loads, the algorithm fits the energy function of battery energy release with the changes of load power. According to the related standards, standard load is chosen. Refer to the definition of SOCS proposed in the preamble, the present stored energy of battery is calculated, the residual capacity from battery discharge until cut-off condition is solved, and estimation of dynamic SOCd is realized finally. As common energy storage equipment, the vanadium redox flow battery (VRB) is cited for experimental verification. The experiment proves that the method is easy to be implemented with less error.

A train driven by a linear thyristor motor (LTM) moves by one pitch of the ground coil in every cycle of the power supply voltage. Therefore the vehicular speed is determined by the power supply frequency, and the travel distance is determined by the number of cycles of the supplied power source voltage. This means that the speed and location of the vehicle are monitored and controlled completely by the power supply system. Hence, no information channel is required at least theoretically which connects the vehicle with the ground station. This paper proposes a power supply and control system for LTM and confirms its operating performances using an outdoor loop-type model system with circumferential length of 100 m.

To ensure the functioning of the energy system, coordination and increase the efficiency of its parts need new control mechanisms. Generation, transmission and consumption of electricity needed control mechanisms that include integration of self-organizing power and heat supply systems, built on multi-agent principle. Also they must correspond intellectual basis, monitoring and accumulation. This includes effectiveness assessment of the state and analysis of technical, technological and organizational management mechanisms. One of the main parts is interaction principles of energy systems in accordance with European Community policy at various levels at liberalized electricity market. In most developed countries, demand management programs are widely used as a means of harmonizing the modes of generation and consumption in the power supply system. The main direct methods are set in the form of electricity tariffs. Indirect methods are set in the form of programs to manage electricity demand and the possibility of their application to manage electricity demand. Methods for estimating the unevenness of the daily schedule of electricity consumption and the factors influencing the technological environment are presented. The work aims at scientific and applied problem – finding methods of estimation and features of managing the demand for electricity. The use of the proposed estimation methods of electricity consumption influence non-uniformity on the level of power supplies system losses based on Frize QF power and optimization of consumers’ operation modes in the power supply system is considered. Approaches and optimization mechanisms of the daily electricity consumption on the example of a residential complex with the possibility of energy accumulation are offered

An individual power supply source is usually used for each group of identical magnetic elements in accelerators of charge particles. We discuss the power supply and control system on the basis of additional current shunts applied for the simultaneous supply of several groups of magnets in the positron storage ring of the Low-Energy Particle Toroidal Accumulator (LEPTA). Data on the use of the shunt of the linear and key converter are given. The option of the device of a power supply system with the transformation of the recuperated energy in the storage battery and supply from it of the precision power supply sources of the LEPTA correcting magnets is considered. A channel of the individual digital transformation of power supply system elements is given which allows one to build, together with a reverse precision converter, effective intellectual balanced power supply systems.

It is highly critical that renewable energy-based power generation units provide continuous and high-quality electricity. This requirement is even more pronounced in standalone wind–diesel systems where the wind power is not always constant or available. Moreover, it is desired that the extracted power be maximized in such a way that less fuel is consumed from the diesel engine. This paper proposes a novel method to design decentralized model-predictive controllers to control the frequency and power of a single standalone generation system, which consists of a wind turbine subsystem mechanically coupled with a diesel engine generator subsystem. Two decentralized model-predictive controllers are designed to regulate the frequency and active power, while the mechanical coupling between the two subsystems is considered, and no communication links exist between the two controllers. Simulation results show that the proposed decentralized controllers outperform the benchmark decentralized linear-quadratic Gaussian (LQG) controllers in terms of eliminating the disturbances from the wind and load power changes. Furthermore, it is demonstrated that the proposed control strategy has an acceptable robust performance against the concurrent variations in all parameters of the system as compared to the LQG controllers.

Transient stability of a MicroGrid in which the micro sources using the peer-to-peer and master-slave control was investigated. The P-f and Q-V droop control was used for micro sources 1 and 2. And the PQ control was used for micro source 3. The impacts of motor load on the transient stability of the MicroGrid were shown when the motor load starts, load power changes and a three-phase faults happens. And the power sharing between each micro sources and the main frequency supporting are achieved. Simulation results have verified the effectiveness of the proposed control strategy.

Dc microgrids during voltage transients or load power changes are prone to instability due to the negative impedance characteristics of the constant power loads (CPLs). The newly proposed T-Type Modular Dc Circuit Breaker (T-Breaker) integrates current breaking, current limiting and grid transient compensation functions into one device thanks to its integrated energy storage and modular multilevel converter structures. Much like the current and voltage compensations in ac systems, the T-Breaker can help the ride-through of grid transients by implementing shunt (current) and series (voltage) compensations. This paper focuses on the series compensation function of the T-Breaker which can insert or absorb voltage. Related system modeling, small signal analysis, large signal analysis, simulation are presented here. Experimental validation result on a scaled down system is also presented to show how the compensation improves the microgrid’s stability.

The program of measures to introduce modern resource-saving technologies for the most effective management of renewable resources will provide the necessary amount of energy to both the population and industrial enterprises. The energy power supply system includes energy power plants using various renewable energy sources (hydraulic, wind, solar) that create more favorable conditions for its stability modes. Unification of power plant using various renewable energy sources (hydraulic, wind, solar) in power supply system has created more favorable conditions for use of power resources. These power plants have their own features of operation modes and definite work place in the production schedule of power supply system. During power supply operation daily production schedules define an operating mode of the system as a whole, including all its elements, from generating sources to high-voltage transmission lines and distributive networks system. The results of given researches are allowed to create the methods of increasing stability, reliability and efficiency supply systems with using renewable energy sources.

Electric drive elements are a common network load in power supply systems. Inaccuracies in the electric machine installation and changes in the load, lead to constant changes in power consumption, including in the vibration event. Vibration forces have a negative effect on the machine mechanical fastenings and the mechanism. Vibration control is usually provided by specialized portable equipment. As a result vibrations there are deviations in electric power which occupy one of key places. Therefore, to monitor the processes in the induction motor, it is necessary to monitor the electric machine power. To obtain the necessary information on changes in power, developed a device for collecting electrical signals of the power circuit and a program for data processing. The device is designed for data collection both in places with access to power from the network, and in places with the appropriate voltage, for direct connection to the network. The program is based on wavelet transform of instantaneous three phases power, which allows you to convert a signal from the time domain to the frequency time. From the total power observation in the frequency-time domain, two frequency bands with constant expressed signals were obtained. In addition, due to a experiments series, a constant decrease in the amplitude power fluctuations with a frequency lower than the mains voltage frequency was determined.

This Paper discusses the effects of load parameters and their variations on power system frequency. In this study an interconnected three area hydro-thermal power system with conventional PI controller and fuzzy logic controller is selected. From the mathematical modeling of power system, frequency is a function of power system parameters and for small changes in these parameters leads to small deviations in the system frequency. In case of extreme ends of parameters, even for small changes in load power there will be a chance of instability in overall power system. This paper deals both stable and unstable cases for different parameter variations. Simulations are carried out in MATLAB/SIMULINK software.