Reliability characteristics of power plants

This paper describes the phenomenon of reliability of power plants. It gives an explanation of the terms connected with this topic as their proper understanding is important for understanding the relations and equations which model the possible real situations. The reliability phenomenon is analysed using both the exponential distribution and the Weibull distribution. The results of our analysis are specific equations giving information about the characteristics of the power plants, the mean time of operations and the probability of failure-free operation. Equations solved for the Weibull distribution respect the failures as well as the actual operating hours. Thanks to our results, we are able to create a model of dynamic reliability for prediction of future states. It can be useful for improving the current situation of the unit as well as for creating the optimal plan of maintenance and thus have an impact on the overall economics of the operation of these power plants

Recursive Sine Wave Digital Oscillator with New Method Used for Amplitude Control

This work describes the control of the amplitude of the output signal (or amplitude stabilization) in digital sine recursive oscillators. As in the case of analog oscillators, it is also necessary to control the amplitude of digital oscillators with a sine wave. If the amplitude is not controlled, exponential increase or decay of the oscillation amplitude occurred, even if floating-point arithmetic is used. An example of digital sine recursive oscillator control with quadrature outputs, simulation results and design results are given in detail. Oscillator amplitude control is performed in a completely new way with a simple and fast algorithm for finding the maximum (minimum) and amplitude correction in case the amplitude differs from the desired value. The advantage is that the oscillator can be simply implemented by a program in the microcontrolle

Output Overvoltage in DC-DC Switching Converters in Case of Sudden Unloading

In present time the high efficiency switching DC/DC converters, e.g. buck and boost are often used. This work describes some problems of DC-DC converters, which can occur, when the load is suddenly disconnected or simultaneous disconnection of the load and the capacitor at the output. The results were derived both by simulation but also by measurement. A special measuring system has been developed for these measurements, which enables the realization of fault conditions. Therefore, measurements were performed on 2 different types of DC-DC converters. The results of simulations and measuring are presented in the work. Error conditions usually cause an overvoltage that can damage the equipment connected to the converter. A solution how to prevent overvoltage and thus damage connected systems is also described

Electronic System for Reduction of Transient Inrush Current in Transformer

This paper introduces a methodology to investigate controlled switching (or "Point on Wave Switching") to reduce magnetizing inrush current in Transformer. When transformer is switched on, transformer will get energized and transiently, large current flows through the primary winding. This mentioned current is - transient inrush current and it may raise up to ten times (or more) the nominal current of transformer during operation. Though transient inrush current lasts within few cycles, it has some bad effects e.g. problems with operations of protective devices, production of mechanical stress to the transformer core, power system quality, problems with sensitive electrical loads such as medical equipment and computers connected to the grid. Hence decreasing of transient inrush currents is important. The method using controlled switching means connect transformer at the correct phase voltage waveform to achieve the minimum inrush current. This reliable method was chosen to prevent generation of high magnitude inrush current. The non expensive electronic system for inrush current decreasing for single phase transformer switching on was developed and successfully tested in practical use

The speed up of vibrating hydraulic jaws by smart control of electric solenoids

CZ.01.1.02/0.0/0.0/19_262/0020258, SGS-2021-005Advanced Electro-Hydraulic Systems (AEHS) are the only way to achieve top-notch parameters for high-end vibration machines. The AEHS is intended to a more complex forming test system developed at University of West Bohemia. The AEHS speeds up the hydraulic by increasing pressure in the plunger box by pistons driven by solenoids with proper timing. The development and testing of the AEHS device are described in the paper

First Search for Exclusive Diphoton Production at High Mass with Tagged Protons in Proton-Proton Collisions at √s=13 TeV

A search for exclusive two-photon production via photon exchange in proton-proton collisions, pp→pγγp with intact protons, is presented. The data correspond to an integrated luminosity of 9.4 fb−1 collected in 2016 using the CMS and TOTEM detectors at a center-of-mass energy of 13 TeV at the LHC. Events are selected with a diphoton invariant mass above 350 GeV and with both protons intact in the final state, to reduce backgrounds from strong interactions. The events of interest are those where the invariant mass and rapidity calculated from the momentum losses of the forward-moving protons match the mass and rapidity of the central, two-photon system. No events are found that satisfy this condition. Interpreting this result in an effective dimension-8 extension of the standard model, the first limits are set on the two anomalous four-photon coupling parameters. If the other parameter is constrained to its standard model value, the limits at 95% confidence level are |ζ1|<2.9×10−13 GeV−4 and |ζ2|<6.0×10−13 GeV−4

Measurement of single-diffractive dijet production in proton–proton collisions at √ s = 8 TeV with the CMS and TOTEM experiments

Measurements are presented of the single-diffractive dijet cross section and the diffractive cross section as a function of the proton fractional momentum loss ξ and the four-momentum transfer squared t. Both processes p p → p X and p p → X p , i.e. with the proton scattering to either side of the interaction point, are measured, where X includes at least two jets; the results of the two processes are averaged. The analyses are based on data collected simultaneously with the CMS and TOTEM detectors at the LHC in proton–proton collisions at s√=8TeV during a dedicated run with β∗=90m at low instantaneous luminosity and correspond to an integrated luminosity of 37.5nb−1. The single-diffractive dijet cross section σ p X jj, in the kinematic region ξ40GeV, and pseudorapidity |η|<4.4, is 21.7±0.9(stat)+3.0−3.3(syst)±0.9(lumi)nb. The ratio of the single-diffractive to inclusive dijet yields, normalised per unit of ξ, is presented as a function of x, the longitudinal momentum fraction of the proton carried by the struck parton. The ratio in the kinematic region defined above, for x values in the range −2.9≤log10x≤−1.6, is R=(σ p X jj/Δξ)/σjj=0.025±0.001(stat)±0.003(syst), where σ p X jj and σjj are the single-diffractive and inclusive dijet cross sections, respectively. The results are compared with predictions from models of diffractive and nondiffractive interactions. Monte Carlo predictions based on the HERA diffractive parton distribution functions agree well with the data when corrected for the effect of soft rescattering between the spectator partons

Odderon Exchange from Elastic Scattering Differences between pp and p¯p Data at 1.96 TeV and from pp Forward Scattering Measurements

We describe an analysis comparing the p¯p elastic cross section as measured by the D0 Collaboration at a center-of-mass energy of 1.96 TeV to that in pp collisions as measured by the TOTEM Collaboration at 2.76, 7, 8, and 13 TeV using a model-independent approach. The TOTEM cross sections, extrapolated to a center-of-mass energy of √s=1.96 TeV, are compared with the D0 measurement in the region of the diffractive minimum and the second maximum of the pp cross section. The two data sets disagree at the 3.4σ level and thus provide evidence for the t-channel exchange of a colorless, C-odd gluonic compound, also known as the odderon. We combine these results with a TOTEM analysis of the same C-odd exchange based on the total cross section and the ratio of the real to imaginary parts of the forward elastic strong interaction scattering amplitude in pp scattering for which the significance is between 3.4σ and 4.6σ. The combined significance is larger than 5σ and is interpreted as the first observation of the exchange of a colorless, C-odd gluonic compound