Horia Andrei - Academia.edu (original) (raw)
Papers by Horia Andrei
The Scientific Bulletin of Electrical Engineering Faculty, Apr 6, 2017
The advance in the field of augmented reality (AR) allows newer approaches to traditional activit... more The advance in the field of augmented reality (AR) allows newer approaches to traditional activities, such as service, maintenance or intervention in various field operations. The idea of this paper is to present the design for an innovative AR platform which is currently under development and is designed to be used in Electrical Power Stations. Field data from sensors and additional information stored in QR tags placed on equipment's are transmitted to a server and from here to the AR equipment's carried by the intervention personnel. In this case, real time data can be displayed, enhancing the perception of team members and providing additional info that can help them to fulfill their mission.
Studies in systems, decision and control, Oct 6, 2019
Traditional industrial control systems (ICS) were implemented especially for isolated system and ... more Traditional industrial control systems (ICS) were implemented especially for isolated system and used specialized hardware and software control protocols. Along with development of low-cost Internet Protocol (IP) devices, the ICS adopting new information technologies (IT) solutions to promote systems connectivity and data communication.
2019 6th International Symposium on Electrical and Electronics Engineering (ISEEE), 2019
The role of safety and resiliency of the power system is a concept already applied in several sec... more The role of safety and resiliency of the power system is a concept already applied in several sectors, although making its way harder in the power system sector. This paper considers the progress made by implementing the new technologies in terms of security systems and draws attention to the vulnerabilities arising with this kind of integration. The main benefit consists of active shielding against presumed attacks, yet once succeeding an attack can determine serious consequences. As a risk scenario, it is considered a cyber-attack that aims to change the security parameters of an electrical transformer station. Here, included is a model regarding the effects of such an attack. As a safety measure, to counteract such a possible attack, one can propose the use of encryption methods for the transformer's parameters.
2022 14th International Conference on Electronics, Computers and Artificial Intelligence (ECAI), Jun 30, 2022
The production of electric and thermal energy using biomass is extremely important in the current... more The production of electric and thermal energy using biomass is extremely important in the current context of the financial crisis and the continuous decrease of the reserves of conventional energy sources. This article analyzes the opportunity to locate the cogeneration plant that uses biomass from a rich region of Romania in this unconventional resource. Then the technical-economic indicators obtained by the plant during 6 years of operation are presented and analyzed. These indicators are used to develop a financial forecast extremely useful for the future development of the analyzed plant.
The authors of this article analyzed in previous papers, published in several international confe... more The authors of this article analyzed in previous papers, published in several international conferences, the behaviour of a residential security system consisting of anti-theft alarm and closed-circuit television system (CCTV) or otherwise known as video surveillance system. They also mathematically modelled the behavior of the components of the two security systems. This article concludes this study by conducting a cost analysis form the point of view of the beneficiary, taking into account the investment costs and those of subsequent operation (energy consumption, maintenance, consumables).
Thermoelectric refrigerators based on the Peltier effect are gaining relevance in some applicatio... more Thermoelectric refrigerators based on the Peltier effect are gaining relevance in some applications in which the refrigerator is subject to particular conditions that limit the usage of more efficient refrigeration technologies such as vapour compression refrigerators. The characterisation of a thermoelectric refrigerator can be done in different ways, by using analytical or computational models. A practical approach is to resort to the electro-thermal analogy, with the transformation of the thermal quantities into their electrical counterpart. This paper starts from the thermoelectric refrigerator model constructed by using the electro-thermal analogy and provides some developments on the equation formulations and usage in stationary conditions, seen as the initial step to initialize the circuit variables. The model of the thermoelectric refrigerator and the details of the electro-thermal analogy are illustrated in a tutorial way for educational purposes.
It is not possible to speak about a complete security system without also taking into account the... more It is not possible to speak about a complete security system without also taking into account the video surveillance system (CCTV). The reason is that CCTV systems offer the most spectacular results both in the security of goods and people and in the field of customer relations, marketing, traffic monitoring and the list can go on. With the development of the software industry the applicability of CCTV systems has greatly increased, largely due to image processing applications. The present paper, which is the continuation of an article already presented at an international conference, aims to shape the electrical characteristics of a common video surveillance system. The proposed method will be validated in two different programming environments.
Power quality analysis is one of the most important subjects of every power systems’ interconnect... more Power quality analysis is one of the most important subjects of every power systems’ interconnected parts. In fact, the nonsinusoidal regime represents the real operation mode of all the power systems, due mainly to distribution and consumers. Several parameters of power quality analysis are used by every national power system operator to impose specific standard limits and regulation which ensure optimal conditions of the electrical energy quality. Generally, all the limit values must be respected, even though they indirectly depend on one another. This paper proposes new relations between some parameters of power quality for the case of most common linear and inductive consumers, in order to unify the limits imposed on nonsinusoidal regime. Starting by the definition of relative values of voltage and current harmonics a new nonlinear dependence between the power factor and the total harmonic distortion of voltage and current is established. A quantitative approach of the nonlinear function has been assessed by using Matlab tools. The results are compared and discussed to the measured data for a large industrial consumer in two cases: with and without filters for power factor correction.
The Scientific Bulletin of Electrical Engineering Faculty, Oct 1, 2017
The paper presents the main electrical loads that require reactive power, evaluating also its val... more The paper presents the main electrical loads that require reactive power, evaluating also its value in different operating states of the industrial installation (permanent sinusoidal or distorted). Also, the effects of reactive power flow in the networks are quantitatively estimated and accordingly, a series of specific power quality indicators (e.g. power factor, crest factor, total harmonic distortion) are highlighted. Different types of solutions dedicated to reduce the level of reactive power are also suggested. The proper design of the power factor correction systems is directly correlated with the consumer power quality parameters. A case-study will round up the work, underling the major importance of the reactive power flow in modern electric installations.
In recent years, security systems have become a necessity for both companies and the residential ... more In recent years, security systems have become a necessity for both companies and the residential sector. This is partly due to the growing national and international crime rate, and on the other hand to legislation in force at European Union level, which in some states goes as far as obliging the owner to implement a security system in order to make the reception of the built house. This paper aims to analyze the energy consumption of a security system for a residential house, reporting this consumption to the average national consumption of a household. For this analysis a common security system has been taken into account, as requested by the majority of beneficiaries. The sizing of the system to match most of the demands of residential homeowners has been carried out by the authors who are security systems specialists with more than 12 years of experience.
In Romania, schools are some of the largest power consumers, accounting for about 25% of public p... more In Romania, schools are some of the largest power consumers, accounting for about 25% of public power-consuming institutions. Considering the common energy profile, which represents the vast majority of consumer cases of the same type existing in classrooms, in laboratories, in heating and lighting systems, the monitoring and analysis of electrical energy parameters, may be extremely important. Based on the data obtained from the data acquisition system, becomes possible to develop advanced algorithms for modeling a school-type consumer and finally to improve the power quality. Also, the energy parameters are compared to those established by international standards to do the power quality analysis. The presentation of the data acquisition system, the results obtained and the analysis of the electrical energy parameters for an example of a school-type consumer are the basic topics of this article.
The explosive growth and diversity in industrial and residential consumers has generated major pr... more The explosive growth and diversity in industrial and residential consumers has generated major problems of the power quality in power systems. Both industry suppliers through the generation of nonsinusoidal regime and consumers with the nonlinear loads cause high disturbances in the power systems. The behavior of nonlinear circuit elements is analyzed in this paper by means of simple mathematical model that uses the multinomial theorem. In order to calculate the distortion of current a new symbolic algorithm is implemented where the harmonic distribution of supply voltage and the nonlinear voltage-current characteristics of circuit elements are considered as input data. The obtained results are compared and validated with traditional simulation techniques.
The Scientific Bulletin of Electrical Engineering Faculty, Apr 1, 2019
In this article we present some simulation models regarding the occurences that affect the qualit... more In this article we present some simulation models regarding the occurences that affect the quality of the electricity supplied to a low voltage consumer. We believe that these will offer to the researcher the opportunity to simulate power quality deviations in different energy system models, thus providing a picture regarding the way those deviations propagate and behave, creating a few basic patterns for studying the energy quality, also taking into consideration the limitations of the system in respect to the software used and the human factor performing the research.
The Scientific Bulletin of Electrical Engineering Faculty, Apr 6, 2017
The advance in the field of augmented reality (AR) allows newer approaches to traditional activit... more The advance in the field of augmented reality (AR) allows newer approaches to traditional activities, such as service, maintenance or intervention in various field operations. The idea of this paper is to present the design for an innovative AR platform which is currently under development and is designed to be used in Electrical Power Stations. Field data from sensors and additional information stored in QR tags placed on equipment's are transmitted to a server and from here to the AR equipment's carried by the intervention personnel. In this case, real time data can be displayed, enhancing the perception of team members and providing additional info that can help them to fulfill their mission.
Studies in systems, decision and control, Oct 6, 2019
Traditional industrial control systems (ICS) were implemented especially for isolated system and ... more Traditional industrial control systems (ICS) were implemented especially for isolated system and used specialized hardware and software control protocols. Along with development of low-cost Internet Protocol (IP) devices, the ICS adopting new information technologies (IT) solutions to promote systems connectivity and data communication.
2019 6th International Symposium on Electrical and Electronics Engineering (ISEEE), 2019
The role of safety and resiliency of the power system is a concept already applied in several sec... more The role of safety and resiliency of the power system is a concept already applied in several sectors, although making its way harder in the power system sector. This paper considers the progress made by implementing the new technologies in terms of security systems and draws attention to the vulnerabilities arising with this kind of integration. The main benefit consists of active shielding against presumed attacks, yet once succeeding an attack can determine serious consequences. As a risk scenario, it is considered a cyber-attack that aims to change the security parameters of an electrical transformer station. Here, included is a model regarding the effects of such an attack. As a safety measure, to counteract such a possible attack, one can propose the use of encryption methods for the transformer's parameters.
2022 14th International Conference on Electronics, Computers and Artificial Intelligence (ECAI), Jun 30, 2022
The production of electric and thermal energy using biomass is extremely important in the current... more The production of electric and thermal energy using biomass is extremely important in the current context of the financial crisis and the continuous decrease of the reserves of conventional energy sources. This article analyzes the opportunity to locate the cogeneration plant that uses biomass from a rich region of Romania in this unconventional resource. Then the technical-economic indicators obtained by the plant during 6 years of operation are presented and analyzed. These indicators are used to develop a financial forecast extremely useful for the future development of the analyzed plant.
The authors of this article analyzed in previous papers, published in several international confe... more The authors of this article analyzed in previous papers, published in several international conferences, the behaviour of a residential security system consisting of anti-theft alarm and closed-circuit television system (CCTV) or otherwise known as video surveillance system. They also mathematically modelled the behavior of the components of the two security systems. This article concludes this study by conducting a cost analysis form the point of view of the beneficiary, taking into account the investment costs and those of subsequent operation (energy consumption, maintenance, consumables).
Thermoelectric refrigerators based on the Peltier effect are gaining relevance in some applicatio... more Thermoelectric refrigerators based on the Peltier effect are gaining relevance in some applications in which the refrigerator is subject to particular conditions that limit the usage of more efficient refrigeration technologies such as vapour compression refrigerators. The characterisation of a thermoelectric refrigerator can be done in different ways, by using analytical or computational models. A practical approach is to resort to the electro-thermal analogy, with the transformation of the thermal quantities into their electrical counterpart. This paper starts from the thermoelectric refrigerator model constructed by using the electro-thermal analogy and provides some developments on the equation formulations and usage in stationary conditions, seen as the initial step to initialize the circuit variables. The model of the thermoelectric refrigerator and the details of the electro-thermal analogy are illustrated in a tutorial way for educational purposes.
It is not possible to speak about a complete security system without also taking into account the... more It is not possible to speak about a complete security system without also taking into account the video surveillance system (CCTV). The reason is that CCTV systems offer the most spectacular results both in the security of goods and people and in the field of customer relations, marketing, traffic monitoring and the list can go on. With the development of the software industry the applicability of CCTV systems has greatly increased, largely due to image processing applications. The present paper, which is the continuation of an article already presented at an international conference, aims to shape the electrical characteristics of a common video surveillance system. The proposed method will be validated in two different programming environments.
Power quality analysis is one of the most important subjects of every power systems’ interconnect... more Power quality analysis is one of the most important subjects of every power systems’ interconnected parts. In fact, the nonsinusoidal regime represents the real operation mode of all the power systems, due mainly to distribution and consumers. Several parameters of power quality analysis are used by every national power system operator to impose specific standard limits and regulation which ensure optimal conditions of the electrical energy quality. Generally, all the limit values must be respected, even though they indirectly depend on one another. This paper proposes new relations between some parameters of power quality for the case of most common linear and inductive consumers, in order to unify the limits imposed on nonsinusoidal regime. Starting by the definition of relative values of voltage and current harmonics a new nonlinear dependence between the power factor and the total harmonic distortion of voltage and current is established. A quantitative approach of the nonlinear function has been assessed by using Matlab tools. The results are compared and discussed to the measured data for a large industrial consumer in two cases: with and without filters for power factor correction.
The Scientific Bulletin of Electrical Engineering Faculty, Oct 1, 2017
The paper presents the main electrical loads that require reactive power, evaluating also its val... more The paper presents the main electrical loads that require reactive power, evaluating also its value in different operating states of the industrial installation (permanent sinusoidal or distorted). Also, the effects of reactive power flow in the networks are quantitatively estimated and accordingly, a series of specific power quality indicators (e.g. power factor, crest factor, total harmonic distortion) are highlighted. Different types of solutions dedicated to reduce the level of reactive power are also suggested. The proper design of the power factor correction systems is directly correlated with the consumer power quality parameters. A case-study will round up the work, underling the major importance of the reactive power flow in modern electric installations.
In recent years, security systems have become a necessity for both companies and the residential ... more In recent years, security systems have become a necessity for both companies and the residential sector. This is partly due to the growing national and international crime rate, and on the other hand to legislation in force at European Union level, which in some states goes as far as obliging the owner to implement a security system in order to make the reception of the built house. This paper aims to analyze the energy consumption of a security system for a residential house, reporting this consumption to the average national consumption of a household. For this analysis a common security system has been taken into account, as requested by the majority of beneficiaries. The sizing of the system to match most of the demands of residential homeowners has been carried out by the authors who are security systems specialists with more than 12 years of experience.
In Romania, schools are some of the largest power consumers, accounting for about 25% of public p... more In Romania, schools are some of the largest power consumers, accounting for about 25% of public power-consuming institutions. Considering the common energy profile, which represents the vast majority of consumer cases of the same type existing in classrooms, in laboratories, in heating and lighting systems, the monitoring and analysis of electrical energy parameters, may be extremely important. Based on the data obtained from the data acquisition system, becomes possible to develop advanced algorithms for modeling a school-type consumer and finally to improve the power quality. Also, the energy parameters are compared to those established by international standards to do the power quality analysis. The presentation of the data acquisition system, the results obtained and the analysis of the electrical energy parameters for an example of a school-type consumer are the basic topics of this article.
The explosive growth and diversity in industrial and residential consumers has generated major pr... more The explosive growth and diversity in industrial and residential consumers has generated major problems of the power quality in power systems. Both industry suppliers through the generation of nonsinusoidal regime and consumers with the nonlinear loads cause high disturbances in the power systems. The behavior of nonlinear circuit elements is analyzed in this paper by means of simple mathematical model that uses the multinomial theorem. In order to calculate the distortion of current a new symbolic algorithm is implemented where the harmonic distribution of supply voltage and the nonlinear voltage-current characteristics of circuit elements are considered as input data. The obtained results are compared and validated with traditional simulation techniques.
The Scientific Bulletin of Electrical Engineering Faculty, Apr 1, 2019
In this article we present some simulation models regarding the occurences that affect the qualit... more In this article we present some simulation models regarding the occurences that affect the quality of the electricity supplied to a low voltage consumer. We believe that these will offer to the researcher the opportunity to simulate power quality deviations in different energy system models, thus providing a picture regarding the way those deviations propagate and behave, creating a few basic patterns for studying the energy quality, also taking into consideration the limitations of the system in respect to the software used and the human factor performing the research.