The growth in the system load accompanied by an increase of power loss in the distribution system. Distributed generation (DG) is an important identity in the electric power sector that substantially overcomes power loss and voltage drop problems when it is coordinated with a location and size properly. In this study, the DG integration into the network is optimally distributed by considering the load conditions in different load models used to surmount the impact of load growth. There are five load models tested namely constant, residential, industrial, commercial and mixed loads. The growth of the electrical load is modeled for the base year up to the fifth year as a short-term plan. Minimization of system power loss is taken as the main objective function considering voltage limits. Determination of the location and size of DG is optimally done by using the breeder genetic algorithm (BGA). The proposed studies were applied to the IEEE 30 radial distribution system with single and multiple placement DG scenarios. The results indicated that installing an optimal location and size DG could have a strong potential to reduce power loss and to secure future energy demand of load models. Also, commercial load requires the largest DG active injection power to maintain the voltage value within tolerable limits up to five years.

Th This paper presents a simple method of evaluating the load resistance and stiffness of corrugatedsheets locally loaded with suspended technical fixtures. As a part of this research, parametricnumerical analyses of corrugated sheets of different span, and with differently located concentratedforces, were carried out. Stress distributions in the individual folds in the elastic range and inthe ultimate limit state were identified. On their basis, equivalent concentrated load factors forthe individual folds in the sheet were determined. The load factors enable analyses of the loadresistance and stiffness of corrugated sheets loaded with concentrated forces, which can be helpfulin design practice.

The objective of the submitted paper is to analyze the influence of the load on the calibration of micro-hardness and hardness testers. The results were validated by Measurement Systems Analysis (MSA), Analysis of Variance (ANOVA) and Z-score. The relationship between the load and micro-hardness in calibration of micro-hardness testers cannot be explained by Kick's Law (Meyer's index "n" is different from 2). The conditions of Kick's Law are satisfied at macro-hardness calibration, the values of "n" are close to 2, regardless of the applied load. The apparent micro-hardness increases with the increase of the load up to 30 g; the reverse indentation size effect (ISE) behavior is typical for this interval of the loads. The influence of the load on the measured micro-hardness is statistically significant for majority of calibrations.

This work deals with the analysis of elasto-plastic post-buckling state of rectangular laminated plates subjected to combined loads, such as uniform compression and shear. The plates are built of specially orthotropic symmetrical layers. The analysis is carried out on the basis of nonlinear theory of orthotropic plates involving plasticity. The solution can be obtained in the analytical-numerical way using Prandtl-Reuss equations. The preliminary results of numerical calculations are also presented in figures.

The effect of air humidity on transonic flow around an NACA0012 airfoil at flow conditions, characteristic for buffet phenomenon, was investigated experimentally. Airfoil angles of attack in the range from 6° up to 10° were used, whereas values of initial relative air humidity were kept constant at four values 12%, 40%, 60% and 80%. Reconstructed time depending airfoil pressure distributions, time histories of normal aerodynamic force coefficient C, as well values of C0 pulsation are shown on the basis of surface pressure measurements at various humidity levels. The influence of the air humidity on the buffet origin is presented.

The paper presents a new method for measuring the strain and load of wire ropes guide using fiber optic sensors with Bragg gratings. Its principle consists in simultaneous fiber optic measurement of longitudinal strain of the rope and transverse strain of the bolt fixing the rope. The tensometric force transducers which have been used so far were only able to determine the load in the head securing the rope through an indirect measurement using a special strain insert. They required calibration, compensation of temperature changes, as well as periodic checking and calibration. The head fastening the rope required significant design changes. Measurement based on fiber optic sensors does not have these drawbacks and is characterized by a much higher accuracy and safety of measurements, because the working medium is light. The fastening head does not change. The measurement of the rope load may be based on the change of strain value or indirectly by means of measuring the deflection of the bolt fixing the rope holder. The proposed solution consists in placing the optical fiber with Bragg grating inside the bolt. It enables continuous measurements with a frequency of 2 kHz. A special test bench was built at the Research and Supervisory Centre of Underground Mining. Testing on guide ropes was carried out in a mining hoist in the Piast mine.

The paper is devoted to a simply supported rectangular plate subjected to two types of compressive edge loads. The first load is applied uniformly along a part of two opposite edges, the second one has a non-uniform distribution (defined by a half wave of the sin^k function). The critical load value of the plate is located between the values for uniformly distributed and concentrated load. Critical value of thickness of the plate is determined. The problem is solved by the orthogonalization method, and the results are compared with those of numerical analysis done by means of the finite element method.

The assessment of a rock’s behaviour around excavations and the effectiveness of its reinforcement in underground ore mines is dependent on the performance of the rock-bolt and rock-mass interaction, which can be estimated on the basis of appropriately designed measurements. Based on the background of various measurements solutions described in the literature, concerning rock bolt monitoring methods, the authors proposed a new, original device for mass measurements in mine conditions. After examining the advantages and disadvantages of existing constructions, the article presents the essence, principle of operation and method of measuring anchor load in an underground excavation with the a instrument, indicator WK-2/8. The prototype has been carefully researched and successfully tested in a full-scale laboratory environment. This instrument, also referred to as a load indicator or force pad, does not require electrical power and allows for relatively accurate (with a resolution of 10-14kN, up to about 90kN loading capacity) and a remote reading of the axle loading of the anchor (AGH patent) by any person present in the specified area. The device can be installed in mining excavations under loading conditions. The relatively low cost of a measuring instrument, practically used as an additional washer, as well as an easy assembly method, makes it universally applicable in mines where anchoring is used as a means of strengthening the rock.

A flow around an NACA00 12 airfoil at special transonic flow conditions, characterised by damped oscillations of the main flow velocity, was investigated experimentally. On the basic of pressure measurements and flow visualisation, the time depending airfoil loading was reconstructed. Results, presented for a wide range of angle of attack ( a =Q-;-10°), show that during the excitation the normal aerodynamic force behaviour significantly differs from that of quasi- steady conditions. The pressure distributions on the airfoil surface depend on Mach number of the main flow as well on the phase of oscillation (deceleration or acceleration of the main flow velocity). The influence of the air humidity on the pressure distribution, normal aerodynamic force and centre of pressure is also considered.

The effect of air humidity on oscillatory flow around the NACA 0012 airfoil was investigated experimentally at Mach number M=0.71 and airfoil angle of attack a=8.5''. The background tlow oscillations were produced by a rotating rectangular plate placed downstream of the airfoil. The generated oscillation frequencies were in the range from 0.5 up to 1.5 of the buffet frequency. The presented results shown that the normal aerodynamic force variations strongly depend on the excitation frequency and reach a maximum value at frequencies typical to the buffet. The increase of the air humidity leads to considerable diminishing of the aerodynamic force variation.

This paper proposes a fair calculation approach for the cost and emission of generators. Generators also have reactive power requirements along with the active power demand to meet up the total power demand. In this paper, firstly the reactive power is calculated considering the random active power operating points on the capability curve of a generator then the cost for reactive power generation as well as emission are calculated. In order to develop the mathematical function for the reactive power cost and reactive power emission, a curve-fitting technique is applied, which gives the generalised reactive power cost and reactive power emission functions. At the end, the problem is formulated as a multiobjective problem, considering conflicting objectives such as combined active- reactive economic dispatch and combined active-reactive emission dispatch. The problem is converted from the multiobjective load dispatch problem (MOLDP) into a scalar problem, using the weighting method and the best compromised solution has been calculated using the particle swarmoptimization (PSO) technique.Afuzzy cardinal method has been applied to choose the best solution. In order to demonstrate the efficiency of developed functions the proposed method is applied on a 3 generator unit system and a 10 generator unit system, the results obtained show its validity and effectiveness.

In the paper the new constructions of robots, modern technologies of painting and newest methods of paint robots programming were presented. Fanuc P-250iA robot using to painting was characterized. The general characteristic of robot with controller R-30iA was demonstrated. The technology and the paint equipment applied to paint frames and load-carrying boxes was shown. The possibilities of simulation software Roboguide were presented exactly, which is a tool for robot environment simulation on a computer PC. Roboguide system application can reduce the programming time of robots and necessary programs optimization conducted before implementation to production.

A steam generator in a nuclear power plant with a light water reactor is a heat exchanger, in which the heat is being transferred from the primary to the secondary loop (it links the primary and secondary loops). When the power plant is running, the inlet parameters (temperatures and mass flow rates) on both sides of the steam generator can change. It is important to know how the changes of these parameters affect the steam generator performance. The complexity of the processes taking place in the steam generator makes it difficult to create a simulator reflecting its performance under changed conditions. In order to simplify the task, the steam generator was considered as a ‘black box’ with the aim of examining how the changes of the inlet parameters affect the changes of the outlet ones. On the basis of the system (steam generator) response, a simple mathematical model of the steam generator under variable load conditions was proposed. In the proposed model, there are two dimensionless parameters and three constant coefficients. A linear relation between these dimensionless parameters was obtained. The correctness of the model was verified against the data obtained with a steam generator simulator for European Pressured Reactor and AP-600 reactors. A good agreement between the proposed model and the simulator data was achieved.

On-load tap changers (OLTC) are some of the main transformer elements that make voltage adjustment in a power network possible. Their failures often cause shutdowns of distribution transformers. The paper presents research work aimed at the assessment of the technical condition of OLTCs by the acoustic emission method (EA). This method makes the OLTC diagnosis possible without the need of disconnecting the transformer from the system. The measurements were taken in laboratory conditions. The influence on the operation non-concurrence of the power tap changer contacts on the AE registered signals has been investigated. The signals registered were subjected to analyses in the time and time-frequency domains. The result analysis in the time domain was carried out using the Hilbert transform and calculating characteristic times for the particular runs. A short-time Fourier transform was used for the assessment of results in the time-frequency domain.

In the acoustic fatigue experiment for hypersonic vehicle in simulated harsh service environment on ground, acoustic loads on the surface of test pieces of the vehicle need to be measured. However, for the normal microphones without high temperature resistance ability, the near field sound measurement cannot be achieved. In this work, on the basis of previous researches, an acoustic tubes array is designed to achieve the near field measurement of acoustic loads on the surface of the test piece in the supersonic airflow with high temperature achieved by coherent jet oxygen lance. Firstly, the process of designing this acoustic tubes array is introduced. Secondly, the equality of phase differences at the front and at the end of the tubes is stated and proved using a phase differences test with an acoustic tubes array whose design is presented in this text; therefore, the phase differences of signals acquired by microphones can be directly applied to beamforming algorithm to determine the acoustic load source. Finally, using above mentioned acoustic tubes array, measurement of acoustic load, with and without a test piece in the supersonic airflow made by the coherent jet oxygen lance, is conducted respectively, and the measurements results are analyzed.

With the increasing penetration rate of grid-connected renewable energy generation, the problem of grid voltage excursion becomes an important issue that needs to be solved urgently. As a new type of voltage regulation control method, electric spring (ES) can alleviate the fluctuations of renewable energy output effectively. In this paper, the background and basic principle of the electric spring are introduced firstly. Then, considering the influence of an electric spring on noncritical load voltage, noncritical loads are classified reasonably, and based on the electric spring phasor diagram, the control method to meet the noncritical load voltage constraint is proposed. This control method can meet the requirements of voltage excursions of different kinds of noncritical load, increase the connection capacity of the noncritical load and improve the voltage stabilization capacity of the electric spring. Finally, through the simulation case, the feasibility and validity of electric spring theory and the proposed control method are verified.

In this paper, crushability of foundry sand particles was studied. Three kinds of in-service silica sands in foundry enterprises selected as the study object, and foundry sand particles were subjected to mechanical load and thermal load during service were analyzed. A set of methods for simulating mechanical load and thermal load by milling and thermal-cold cycling were designed and researched, which were used to characterize the crushability for silica sand particles, the microstructure was observed by SEM. According to the user’s experience in actual application, the crushability of Sand C was the best and then Sand B, the last Sand A. The results indicated that mechanical load, thermal load and thermal-mechanical load can all be used to characterize the crushability of foundry sand particles. Microscopic appearances can qualitatively characterize the crushability of foundry sand particles to a certain extent, combining with the additions and cracks which are observed on the surface.

A new method measuring of mass in electronic system of scales has been described. The main element of this system is inductive measuring load cell, which was compared with strain gauge load cell. The aim of the paper is described advantages of the inductive measuring system of mass and explain some main problems of this system. Digital correction of the mechanical errors of the beam like: hysteresis, creep material of the beam under constant load, influence of ambient temperature was described.

Currently, the distribution system has been adapted to include a variety of Distributed Energy Resources (DERs). Maximum benefits can be extracted from the distribution system with high penetration of DERs by transforming it into a sustainable, isolated microgrid. The key aspects to be addressed for this transformation are the determination of the slack bus and assurance of reliable supply to the prioritized loads even during contingency. This paper explores the possibilities of transforming the existing distribution system into a sustainable isolated network by determining the slack bus and the optimal locations and capacity of Distributed Generators (DGs) in the isolated network, taking into account the contingencies due to faults in the network. A combined sensitivity index is formulated to determine the most sensitive buses for DG placement. Further, the reliability based on the loss of load in the isolated system when a fault occurs is evaluated, and the modifications required in for reliability improvement are discussed. The supremacy of the transformed isolated network with distributed generators is comprehended by comparing the results from conventional IEEE 33-bus grid connected test system and modified IEEE 33-bus isolated test system having no interconnection with the main grid.

The paper presents the method of probabilistic optimisation of load bearing capacity and reliability of statically indeterminate bar structures, and of coupling of members in kinematically admissible failure mechanisms (KAFM), which contain minimal critical sets of elements (MCSE). The latter are characterised by the fact that if only a single element is operational, the whole set is operational too. A method of increasing load bearing capacity and reliability of KAFM built from bars dimensioned in accordance with the code is presented. The paper also shows estimation of load bearing capacity and reliability of KAFM of the optimised structures containing elastic-plastic bars with quasi-brittle connections with nodes. The necessity of increasing connection of load bearing capacity and reliability in relation to bar reliability in order to prevent bars from being excluded from MCSE due to connection fracture is estimated.

The paper provides a solution to the problem of dimensioning decisive bars on the basis of the conditions of meeting the recommended reliability classes [9] of statically determinate structures composed of n members. A theorem was formulated:if a statically determinate structure composed of n decisive members is to attain the reliability greater than, or equal to, the recommended relia-bility p = 1 – q, it is necessary and suffi cient that the damage frequency sum qᵢ of decisive members is smaller than the admissible damage frequency q of thestructure: ∑qᵢ < q. On the basis of this theorem, s coeffi cients that recommend increase of the load bearing capacity of the decisive bars in a statically determinate structure constructed in order to meet the recommended class [9] of the structure reliability, are estimated and presented in a tabular form.