One promising trend in making voltage converters more reliable is to design them on the basis of backbone modular architecture, combined redundancy, and rotation of main and backup power channels. A technique is proposed for this converter for calculating the upper and the lower failsafe operation probability estimates that is based on using the standardized model for the sliding loaded redundancy group. It is shown that the session rate of failures can be used as the channel fail-safety indicator in the rotation of channels. The proposed technique allows finding these estimates as time functions and considering the rate of channel failures not only in the converter’s running mode, but in the standby mode as well. An example of calculating the converter’s failsafe operation estimates is presented; a similar calculation by imitative modeling is provided to confirm the obtained results. It is shown that a shortened full channel rotation cycle makes the channels spend the resource in a more even manner, has no effect on the converter’s fault-free performance figures at an absolutely reliable switch, and reduces them in the case of an unreliable switch.
A large-scale project is being implemented in Russia to introduce a smart system to account for electricity consumption. Creating a system for rapid restoration of electricity meters should become an obligatory part of the range of services provided to consumers. Operational restoration of electricity meters should also be carried out during the implementation period. It is necessary to determine a nonexcessive number of personnel that will be able to provide both installation of electric meters at a given time and their prompt recovery. The organization of work of the personnel significantly affects its necessary number. In this paper, the task of determining the number of employees is solved under the assumption that the personnel are divided into those who are involved in the installation of electricity meters and those who are responsible for recovery. This division is not carried out at the start, but is varied as the number of electric meters operating in the system increases. Formulas are obtained for calculating the number of personnel that will allow the project to be completed on time. Using these formulas, it can be determined how to change the number of personnel involved in the installation of electricity meters and engaged in restoration during the project implementation period.
Planning electric-rolling-stock (ERS) maintenance in conditions of limited resources can be carried out based on the following criteria of efficiency of construction of the cycle diagram of the electric rolling stock: meeting the requirements of the railway-traffic safety provided by adjusting the planned movement time of the electric rolling stock for the purpose of not allowing an excessive lapse of time between the maintenance over that permissible and uniformity of maintenance. The solution of the set problem using the graph theory allows obtaining the whole set of the permissible values of maintenance and selecting a value that, on the one hand, corresponds to the planned train time schedule (PTTS) and, on the other hand, differs minimally from the optimal with respect to the selected criterion. This takes a significant amount of time. The problem can be quickly solved using a genetic algorithm. The introduction of a new criterion—total excess time lapse between maintenance works over the permissible interval—allows obtaining the solution with any initial data, which is not always achievable when using the uniform-maintenance criterion. The crossover and permutation algorithm implemented within the genetic algorithm is adapted taking into account considering the peculiarities of the agents engaged in solving the problem that has been set out. We have studied the possibility of using various types of crossover and permutation to construct the cycle diagrams and influence of the parameters of the genetic algorithm on the results. The obtained analytical results are tested for the conditions of the Moscow subway.
In the next few years, a large-scale project on implementation of an intelligent system for electric power metering should be carried out in Russia. The replacement of electric meters for individual customers is a necessary part of this project. The number of people needed to carry out the project within the specified period has to be found. It should be taken into account than electric meters, like any electrical equipment, are subject to failure. If a system for their prompt restoration is not developed, the incorporation of an intelligent system of electric power metering will have no effect. The classical queuing analysis based on calculation of the probabilities of a system being in different states can hardly be used because of the problem’s dimensionality. Methods of simulation describe specific cases. They do not provide solution of the problem without analytically determined approximations of the number of people needed. This paper considers the solution of the problem of determining the number of personnel needed for the program of replacing electric meters to be done in proper time, taking into account the that they need to be restored promptly. The solution has been obtained based on the simulations of the incorporation of an intelligent system of electric power metering using the method of average dynamics. An example of calculations of the necessary number of employees in MathCAD PRIME 4.0 has been considered. The suggested method provides almost exact results because of the large number of replaced electric meters.
Automatic control systems (ACSs) for rolling stock should provide desired control quality under all modes of motion (traction, speed stabilization, braking). The structure of an adaptive automatic control system, as well as the methodology of choosing its parameters, the implementation of which makes it possible to achieve the desired control quality in a wide range of speeds and weights of trains, is proposed. In addition, the parameters of the ACS should be changed during changes of modes and train weight.
A train schedule problem consists of some steps: compilation and analysis of source data, requirements formation of a volume traffic in dependency time of a day, requirements maintenance of electric motive power, which determinate necessity for combined generating of train schedule with maintenance schedule. One of the task, which heavy determinate on a procedure automated generating of train schedule combined with maintenance schedule, is solving of trains night stay problem. This article shows some mathematical provision of solving problem of generation all possible variants of trains night stay on station layout. Authors give propose an attitude based of using graph theory for formalization object and finding solution. The devise of algorithmic conforming can be using for station with free configuration of gridiron described by planar graph. It is show that implemented algorithms are (tree construction and sealing of the graph) equivalent veracity of isomorphism graph structure. Balance of the work it is not only program product, it is represent determinate algorithm and method of formalization definition gridiron.
Dependability of power electronics products designed for power supply of electronic equipment, largely determine its dependability, because failure of the power supply system, as a rule, leads to failure of the equipment as a whole. Therefore, the secondary power supply must be highly reliable. To ensure the required dependability of power supplies, various methods of their construction and redundancy are used. Early stages of design determine the dependability that will be implemented in the manufacture and maintained during operation. At these stages, dependability prediction are of paramount importance.
The complexity of power supply architectures and the use of redundancy in them leads to the complexity of analytical of their dependability prediction and requires the involvement of highly qualified specialists. The use of specialized software that implements simulation modeling in the calculation of structurally complex power supplies also causes certain difficulties associated with the construction of formal models and their verification. Therefore, the improvement of analytical methods to obtain estimates of the dependability of power sources is currently being given a lot of attention.
At present, one of the promising directions of improving the reliability of voltage converters is the use of backbone-modular architecture, mixed redundancy and rotation of the major and redundant power channels. For such a converter, an analytical method for calculating the lower and upper estimate of the reliability function is proposed, which is based on the use of a standardized model for the group "sliding loaded redundancy". It is shown that the channel rotation as the reliability characteristics of the channels can be used cyclic failure rate.
In contrast to the known, the developed method allows to obtain these estimates as a function of time and taking into account the failure rates of the converter channels not only in the operating mode, but also in the standby mode.
An example of calculating the limits of the reliability function of the converter by the proposed method is given, and to confirm the results of the calculation of the same example by simulation. In addition, it is shown that the reduction of the full rotation cycle of the channels increases the uniformity of the resource consumption by the channels with an "absolutely reliable" switch and does not affect the reliability of the converter, and the "unreliable" switch leads to a decrease in reliability.