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Mario Kokorus

Društvene mreže:

A. Foškulo, M. Kokorus

For Utilities, each substation is regarded as an asset. Managing of assets is one of domains of Asset Management including Life Cycle Costing (LCC) as a decision-making criterion. However, LCC as a decision-making criterion should be applied on an entire substation taking into account all of the potential cost influences for the purpose of achieving of an effective substation management. Asset management as a decision-making process should be observed within a larger context and should be more focused on risk management, as all real decisions include an element of risk due to present uncertainties. Two promising avenues are explored in regards to more comprehensive and rigorous up-front planning through usage of Information Technology (IT). While up-front planning falls under the domain of Lean philosophy, Building Information Modeling (BIM) falls under the category of agile decision-support tools. Utilization of both is explored from a perspective of design-uncertainties under both product and process design. Standard specifications and standard designs are another form of applied Lean Philosophy that reduces design-uncertainty and variability. However, a range of technical solutions stemming out of the standardization can be quite wide. Customization involves specification and design of new / innovative designs with wide range of technical solutions as well. Due to external pressures focused on shortening of the project delivery time, there is a need for a faster project time throughput. This is reflected in the form of a requirement for more rapid engineering decision-making and faster decision cycles. Streamlining of a decision-making process related to the engineering is all about engineers’ awareness of the situation from the project level perspective coupled with utilization of decision-support tools for creation and reuse of knowledge. Plan – Do – Study – Orient (PDSO) cycle is a decision-making model that supports creation and reusability of knowledge along with providing an explanation in regards to the time dimension relating to decision-making, and as such is presented in this paper. The rigid busbar system design is an iterative process influenced by many factors, defined either as design variables or design constraints. As rigid busbars are gaining more popularity for both greenfield and brownfield investments, the rigid busbar system design is explored from a perspective of decision-making streamlining. The case of the rigid busbar system design of El Chaparral project in El Salvador is given.

A. Foškulo, M. Kokorus

Effective substation management should include engineering and construction costs. While the construction process has to be methodically planned and sequenced to achieve optimized construction costs, substation designers play a vital role for delivering cost-efficient substations. Integrated design and construction has been proposed as a way to achieve effective project management, which historically viewed, was a responsibility of a “master builder”, thus causing Contractors to identify themselves as “master builders”. As EPC is a highly competitive arena, Contractors are looking for ways to differentiate themselves from their competitors. Some are turning to 3D technologies, while others turn to the design-construction integration. Virtual Master Builder (VMB) supports both 3D technologies and the design-construction integration. Due to a global shortage of worldwide available expertise, Contractors turn to education and training of their employees. While education aims at providing basic skills, training aims to provide the skill necessary to do the job. This paper examines these basic skills as a part of personal mastery before defining organizational learning as a key organizational competence.   Physical Virtuality realm is seen as a fruitful ground for staging of memorable and transformational experiences leading towards achieving “accelerated learning”, and especially 4D models as representations of a “space-time” environment. The project case of Skopje 4 SS 380/110 kV rehabilitation is given as an example of 4D models usage. Project Engineering is seen as a middle ground between engineering and management in order to achieve goals of effective substation management and cost-efficient substation solutions. Project teams are seen as Virtual Design and Construction (VDC) users to achieve these goals.

M. Kokorus, F. Pizarro, W. Eyrich, Sabrina Heuser

Laser scanning today represents one of the most sophisticated geodetic metering methods. This method is becoming more relevant in all substations areas. The challenge is to convert the raw point clouds into smart substation information models. This paper describes how a software provides new tools to radically improve the workflow and the time needed to convert point clouds into intelligent 3D substation models - based on Building Information Modeling (BIM) technology. This then allows experts to take advantage of modern substation engineering methods and calculations.

M. Kokorus, R. Gacanovic, H. Zildzo, Aldijana Ahmovic

Soil moisture variation around the electrical substation grounding system - draining/damping - is usually caused in two ways: (1) seasonal atmospheric changes (atmospheric precipitation, sun, frost) and (2) high intensity and long duration currents flow from the grounding system, e.g. permanent short circuit current in transmission and distribution networks with isolated neutral point of power transformers, return current flow through the ground in the monopolar electrical systems which use ground as a return line (AC and DC electrotransport systems, DC power transmission, "back-to-back” (AC/DC/AC) substations for two unsynchronized systems connection). Changes in moisture cause the change of physical structure of the soil, which is reflected on geo electrical soil characteristics, especially on the specific electrical resistance p. These study of this phenomena and their impact on the main calculation parameters of grounding system will be carried out using the field interdependence model. The analysis will be performed on a real substation and these results will try to give an answer if these phenomena were justifiably or unjustifiably neglected due to their complexity and lack of effective analytical tools in classical grounding design so far.

M. Kokorus, W. Eyrich, R. Zacharias

Rising power demand, on aging infrastructure, causes more and more issues, right up to blackouts. There is a national need for grid rebuilding of the power network over the next decade. The fact that large number of power engineers will be retired in the next years, forces the power industries to look for efficient design solutions. For this reason, it is important to achieve shortened project time, costs reduction, efficiency and accuracy, in substation design. Software which fulfills these requirements, using Building Information Modeling (BIM), is described in this paper. This technology provides planning, designing, building and managing 2D or 3D models, having the intelligence, geometry and data utilizing contained elements. Thanks to BIM, designers of different branches can work more collaborative. Software provides whole electro-mounting, designing, including civil and architectural review.

M. Kokorus, H. Zildzo, R. Gacanovic, Aldijana Ahmovic

This paper presents research of phenomena in the soil around activated grounding system considering behavior of fields and their correlation, as well as reflection of these appearances on main grounding parameters. If through grounding system flows current with significant intensity then generated heat in the soil around grounding electrode will cause heat rise in that soil. Under specific circumstances this heating causes evaporation of moisture in the soil, so that resistance and temperature, considering mutually strong positive feedback, start to rise progressively. This kind of unstable condition causes spiral breakdown, which can be followed by extremely high values of soil resistance, inadmissible high values of grounding system potential and finally by high values of touch voltage and step voltage. Also, a model of fields' correlation shall be tried to be established in the soil around grounding system at the flow of high amplitude currents through that grounding system.

M. Kokorus, R. Gacanovic, Alija Jusić, H. Zildzo

A calculation of the earthing system in a 110/35/10 kV substation using the software package CDEGS is presented in this paper. Also, dangerous touch and step voltages in the same substation were measured using the U-I method in real-life conditions. The aim of this paper is to show the complexity of procedures for earthing system design in a substation, correct and quality performance in accordance with regulations and the law, and monitoring and periodic control measurements during service. Continuous control and analysis of calculation results and measurements guarantee the achievement of correct technical functions and safety of people and animals from injuries by electricity.

This paper deals with design of the substation grounding system by using computer. As it is well known, proper design of the grounding system is most important part of the whole project of the substation, from safety point of view. Procedure of the measurement of the soil resistivity and interpretation of the measured results is given. Interpretation of the soil resistivity data and results of interpretation are explained. Also, calculation procedure of potential distribution of the complex grounding system, grounding system resistance, distribution of touch and step voltage by using a computer are presented. Whole procedure was implemented on the real substation grounding system. Results of the potential distribution on the ground surface of substation touch voltages and step voltages are calculated in the paper. Finally, analysis of the capacitor bank's underground steel construction influence on all relevant parameters of the grounding system is given in this paper.

M. Kokorus, R. Gacanovic, K. Sokolija, Mirza Batalovic, H. Zildzo

This paper describes solving of fields around grounding electrode using Markov Chains - Monte Carlo Method (MCMC). For systems with a very large number of elements and millions of equations which need to be solved, this method is often not applicable as it requires very long computation time. Therefore, it is necessary to improve existing algorithms and methods or develop new ones. The paper presents such attempt - development and application of Conjugate Gradient Method (CGM) mathematical model with Compressed Row Storage (CRS) format in solving fields around grounding electrode. For this, MCMC is used on two-dimensional model with set boundary conditions with the aim of rapid computation of very challenging problems. As an illustration of the proposed method possible application, calculations of thermal fields in the soil around grounding electrode during intensive wave of current are presented.

This paper focuses on the optimization of the design of high voltage transmission lines in order to reduce the negative impact of electric and magnetic fields. Within this paper the results of measurements of electric and magnetic fields near 400 kV transmission line were presented. Measurements were performed in the middle of the range between two towers, because at this point transmission lines are closest to the ground. In order to make better validation of the used calculation models of electric and magnetic fields, measurement of temperature, pressure, humidity and height of particular transmission lines in the middle range, were performed simultaneously. The values of current and voltage on the transmission line, at the time of measurement of the fields, are also given. Based on the measured values of electric and magnetic fields, validation of calculation was performed. This paper also contains a brief comparative analysis of regulations on non-ionizing radiation of power facilities that are in use in some European countries, as well as recommendations of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Calculation of electric and magnetic fields of different configurations of 400 kV transmission line, were performed in order to find optimal solution in terms of reducing the negative impact of electric and magnetic fields of high voltage transmission

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