Development of methodology and measures to ensure the reliability of energy systems equipment

THE PURPOSE: The article presents the results of the development of a methodology for the design calculation of reliability and changes in the level of reliability of energy systems, taking into account the influence of control actions based on statistical methods of collection, analysis and models of experimental data processing.METHODS: The system analysis and generalization of experimental data on technological failures of the main equipment of thermal power plants were used in the calculation assessment.RESULTS: The objective function of controlling the reliability parameters of the thermal power plant power equipment is proposed. The approbation of the presented objective control function was performed, which showed the adequacy of the results obtained to assess the reliability of the main nodes and elements of the TPP power equipment.CONCLUSION: The results of the conducted studies show that when determining reliability indicators, it is necessary to take into account the actual technical condition of individual elements and resource-determining functional units of thermal power plant power equipment. The results obtained can be used to develop a methodology for evaluating control actions for calculating the output control parameters and a mathematical model for changing the output characteristics of TPP steam turbines in terms of heat and electric energy generation, as well as at the stage of developing design documentation for the creation of structural elements and practical recommendations in order to extend the service life of power equipment generating systems based on digital technologies.

Assessment of influence of rolling mill FC-AR electric drive operation mode on 10kV supply network voltage quality

Advanced rolling mill electric drives are based on frequency converters (FC) with active rectifiers (AR). Operation of such converters has negative impact on the in-plant power supply system. To improve the voltage quality of active rectifiers, special algorithms of pulse-width modulation algorithms are used. As a rule, the study of the effect of electric drives with FC-AR on the supply network are carried out based on simplified mathematical models that do not consider possible resonance phenomena in the power supply system and operating mode of electric drives. Thus, the aim of the paper is to assess the acceptability of such an approach. The trends of the main parameters of the rolling mill electric drives have been recorded during the rolling cycle using the IBA PDA software. The obtained dependencies values have been approximated and applied in a complex simulation model of the in-plant power supply system. It considers the parameters of the supply network, cable lines, step-down transformers, rolling mill electric drives and other electrical receivers of the shop substations. The main assumption in simulation modeling is to consider the loads of other electrical receivers in the form of constant values. The authors have studied the effect of the operating modes of the rolling mill electric drive on the electric power quality in the 10 kV distribution network of the in-plant power supply system of a metallurgical enterprise. It is found that the total harmonic distortion KU at 10 kV sections of the main step-down substation of a metallurgical enterprise is changing in a nonlinear manner in the dynamic modes of acceleration and deceleration of electric drives. The nature of the coefficient KU also depends on the presence of resonance phenomena in the frequency response of the medium voltage supply network. The obtained results prove the need to consider the operating modes of electric drives when studying the influence of electric drives with FC-AR on the quality of the supply network voltage. in case we conduct experimental research using the equipment of the enterprises, as well as during theoretical research using mathematical models. The adequacy of the simulation model has previously been confirmed by experimental data and previous studies.

Fast Yaw Optimization for Wind Plant Wake Steering Using Boolean Yaw Angles

In wind plants, turbines can be yawed into the wind to steer their wakes away from downstream turbines and achieve an overall increase in plant power. Mathematical optimization is typically used to determine the best yaw angles at which to operate the turbines in a plant. In this paper, we present a new method to rapidly determine the yaw angles in a wind plant. In this method, we define the turbine yaw angles as Boolean—either yawed at a predefined angle or nonyawed—as opposed to the typical methods of formulating yaw angles as continuous or with fine discretizations. We then optimize which turbines should be yawed with a greedy algorithm that sweeps through the turbines from the most upstream to the most downstream. We demonstrate that our new Boolean optimization method can find turbine yaw angles that perform well compared to a traditionally used gradient-based optimizer where the yaw angles are defined as continuous. There is less than 0.6 % difference in the optimized power between the two optimization methods for randomly placed turbine layouts. Additionally, we show that our new method is much more computationally efficient than the traditional method. For plants with nonzero optimal yaw angles, our new method is generally able to solve for the turbine yaw angles 50–150 times faster, and in some extreme cases up to 500 times faster, than the traditional method.

Algorithms for estimating equivalent resistances of in-plant electrical networks

THE PURPOSE. Investigation of the degree of influence of the characteristics of in- plant electrical networks on the reliability of the results in the algorithms for estimating equivalent resistances. METHODS. When solving this problem, a study of the radial power supply scheme of the tool shop section was carried out with the calculation and modeling of equivalent and reference values of the circuit resistances. Algorithms and methods for estimating the values of equivalent resistances have been developed, taking into account the main technical characteristics of in-plant networks.RESULTS. The data of calculations of the equivalent resistance values of the circuits with an assessment of the heating factor of the conductors and the resistance factor of the contact devices are analyzed. The proportions of the influence of the resistances of the contact equipment and lines, taking into account the number of electric power receivers connected to the power point, on the value of the equivalent resistances of the circuit are revealed. CONCLUSION. The article develops algorithms for estimating the values of equivalent resistances of in-plant power supply circuits. Nomograms are presented that take into account the number and length of the circuit lines with the allocation of the zone of accounting for the resistances of contact equipment in the equivalent resistances of the circuits. The obtained algorithms and results are recommended to be used to clarify the amount of power and electrical energy losses in the intra- factory networks, which will increase the reliability of calculations.

Power Maximization and Turbulence Intensity Management through Axial Induction-Based Optimization and Efficient Static Turbine Deployment

Layout optimization is capable of increasing turbine density and reducing wake effects in wind plants. However, such optimized layouts do not guarantee fixed T-2-T distances in any direction and would be disadvantageous if reduction in computational costs due to turbine set-point updates is also a priority. Regular turbine layouts are considered basic because turbine coordinates can be determined intuitively without the application of any optimization algorithms. However, such layouts can be used to intentionally create directions of large T-2-T distances, hence, achieve the gains of standard/non-optimized operations in these directions, while also having close T-2-T distances in other directions from which the gains of optimized operations can be enjoyed. In this study, a regular hexagonal turbine layout is used to deploy turbines within a fixed area dimension, and a turbulence intensity-constrained axial induction-based plant-wide optimization is carried out using particle swarm, artificial bee colony, and differential evolution optimization techniques. Optimized plant power for three close turbine deployments (4D, 5D, and 6D) are compared to a non-optimized 7D deployment using three mean wind inflows. Results suggest that a plant power increase of up to 37% is possible with a 4D deployment, with this increment decreasing as deployment distance increases and as mean wind inflow increases.