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Papers by krishnav bhatia

IET Science, Measurement & Technology

2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2018

This paper presents touch voltage analysis in TN-S connected earth system. For this purpose, calc... more This paper presents touch voltage analysis in TN-S connected earth system. For this purpose, calculation of touch voltages and touch durations (as per IEEE and International Electrotechnical Committee (IEC) standards) with equivalent formulas is done for different sizes of cable and protective conductor (PE). Cable ampacity calculations for underground cable as well as thermal sizing of cable and PE are presented. Furthermore, in this paper a novel way of improving the safety in TN-S system that is by increasing the size of PE for same cable size is investigated. It is found that not only touch voltage and body current decreases but also touch duration increases which are desirable conditions from safety point of view. Also, effect of different seasons on touch duration and body current are evaluated. Especially, in raining season when soil resistivity becomes quite low, it is shown that with increase in size of PE system can become safer.

2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2018

This paper presents safety analysis of TN-S and TN-C-S earthing system considering different size... more This paper presents safety analysis of TN-S and TN-C-S earthing system considering different sizes of cable and protective earthing conductor (PEC). For this purpose, touch voltage and electric shock calculations are presented. In TN-C-S system, even with the main protective bonding (MPB) and in TN-S system in spite of local grounding at consumer end, computed touch voltages are quite high and thus unsafe for human. Therefore, to safeguard the persons against dangerous touch voltages in both the earthing systems, novel way of protection that is bonding of grounding grid to the exposed conductive part (ECP) of consumer load is proposed in this paper. Also, grid augmentation is investigated for hazardous step and touch voltages. Based on the two cases, that is with and without bonding the ECP of load to grid, touch voltage assessments are done. The results show that with bonding, touch voltages are reduced substantially. Therefore, safety and reliability of the systems are ensured.

around the world with great pace due to which demand for electricity has increased enormously and... more around the world with great pace due to which demand for electricity has increased enormously and it will continue to increase more and more in the time to come. As a matter of fact in the time to come the importance of microgrid either connected with non conventional or conventional sources is going to increase. Microgrid can play a vital role in future electricity transmission. Microgrid alone cannot fulfil the requirement its proper functioning is also required, which means that we would be able to connect or disconnect it to the main grid whenever required. Proper islanding in proper time is required to increase the reliability of the system as a whole. In this paper, the importance of microgrid connected to the main grid and the importance of islanding in proper time is analyzed during the fault in the main grid in the ETAP environment.

2019 IEEE International Conference on Environment and Electrical Engineering and 2019 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2019

Today with increase in use of microgrid, appropriate grounding design is needed for it. In this p... more Today with increase in use of microgrid, appropriate grounding design is needed for it. In this paper it is done by considering different grounding shapes for the MG. For this purpose, paper evaluates the performances of triangular, rectangular, square, L shape and T shape grounding design considering uniform and two layer soil structure. Influence of diverse designs on safety parameters such as touch voltage and step voltage are examined. Investigation is done with the help of ETAP based finite element method and for its authentification, results obtained by it are substantiated with analytical results obtained through IEEE standard 80-2013. As per the results obtained, triangular shape performs better. Also, this paper reveals the touch and step potential profiles for different shapes.

IET Science, Measurement & Technology, 2020

This study examines the sustainability of uniform as well as an optimal grounding grid (GG) desig... more This study examines the sustainability of uniform as well as an optimal grounding grid (GG) design for the microgrid (MG), in terms of variations in the top layer (TL), middle layer (ML), and bottom layer (BL) soil resistivities (ρ 1 , ρ 2 , and ρ 3 , respectively) along with change in a thickness of TL and ML. GG design is highly dependent on ρ 2 , as it helps in determining the density of conductors at grid extremities. With an increase in ρ 2 , touch voltage (TV) crosses its tolerable limit, but step voltage (SV) remains within its limit. However, with a simultaneous increase in the thickness of ML (MLT), SV also crosses its limit. For ρ 2 higher than ρ 3 , with an increase in MLT, TV, and SV increase, while in the reverse case, they decrease. For the given MLT, ρ 3 is crucial in determining GG burial depth. Validation of results is done by comparing them with the IEEE standard. Also, the optimal compression ratio of GG with an increase in MLT is analysed. TVs can be reduced to a great extent, with the application of distinctive methods of earthing (TT-GG system, TN-S-GG system, and TN-C-S-GG system) in MG. This study also reveals that an increase in GG resistance leads to a reduction in TV.

m-hikari.com

In Conventional power converters electromagnetic interference (EMI) emissions comes from the swit... more In Conventional power converters electromagnetic interference (EMI) emissions comes from the switching of a DC voltage in pulse width modulation (PWM) process. The effective way to reduce EMI in power converter is to use frequency modulation technique which modulates the originally constant switching frequency by following a certain modulation profile (i.e. sinusoidal, sawtooth, triangular, exponential, random, chaotic).This paper is dedicated to chaotic switching frequency modulation technique which is the modified form of simple frequency modulation technique and also focusing on the effectiveness of simple frequency modulation in EMI reduction as a function of the different switching modulation profiles. The simulation results show that the EMI spectrum is decided completely by the peak amplitude of PWM spectrum. Chaotic frequency modulation technique is effectively reduce it by using a variable switching frequency (modulating a base value (carrier frequency, fc)) obtained by logistic map(bifurcation technique). And also compare chaotic frequency modulation with all other different modulating profile and finally conclude that chaotic frequency-spreading gives better spectral performances and results.

2019 IEEE International Conference on Environment and Electrical Engineering and 2019 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2019

Microgrids (MG) are generally built up near the load centres. With augment of considerable number... more Microgrids (MG) are generally built up near the load centres. With augment of considerable number of MGs in the present power system, it becomes indispensable to cogently estimate the safety parameters while designing its grounding system. This is mainly due to the closeness of MG grounding to other nearby grounding systems. For this purpose, an interactive mathematical model between the two nearby grounding designs (including MG grounding) is exemplified. It shows that if mutual interaction between the two nearby grounding design are not considered then it leads to overestimation of safety parameters such as touch voltage, ground potential rise and grounding grid resistance. This causes un-necessary expenditure on safety design. Results obtained through mathematical model are substantiated by simulations results acquire through finite element method and are found to be favorable. Further, ground potential distribution profiles through FEM are also found and are in conformity with mathematical model.

IET Science, Measurement & Technology

2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2018

This paper presents touch voltage analysis in TN-S connected earth system. For this purpose, calc... more This paper presents touch voltage analysis in TN-S connected earth system. For this purpose, calculation of touch voltages and touch durations (as per IEEE and International Electrotechnical Committee (IEC) standards) with equivalent formulas is done for different sizes of cable and protective conductor (PE). Cable ampacity calculations for underground cable as well as thermal sizing of cable and PE are presented. Furthermore, in this paper a novel way of improving the safety in TN-S system that is by increasing the size of PE for same cable size is investigated. It is found that not only touch voltage and body current decreases but also touch duration increases which are desirable conditions from safety point of view. Also, effect of different seasons on touch duration and body current are evaluated. Especially, in raining season when soil resistivity becomes quite low, it is shown that with increase in size of PE system can become safer.

2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2018

This paper presents safety analysis of TN-S and TN-C-S earthing system considering different size... more This paper presents safety analysis of TN-S and TN-C-S earthing system considering different sizes of cable and protective earthing conductor (PEC). For this purpose, touch voltage and electric shock calculations are presented. In TN-C-S system, even with the main protective bonding (MPB) and in TN-S system in spite of local grounding at consumer end, computed touch voltages are quite high and thus unsafe for human. Therefore, to safeguard the persons against dangerous touch voltages in both the earthing systems, novel way of protection that is bonding of grounding grid to the exposed conductive part (ECP) of consumer load is proposed in this paper. Also, grid augmentation is investigated for hazardous step and touch voltages. Based on the two cases, that is with and without bonding the ECP of load to grid, touch voltage assessments are done. The results show that with bonding, touch voltages are reduced substantially. Therefore, safety and reliability of the systems are ensured.

around the world with great pace due to which demand for electricity has increased enormously and... more around the world with great pace due to which demand for electricity has increased enormously and it will continue to increase more and more in the time to come. As a matter of fact in the time to come the importance of microgrid either connected with non conventional or conventional sources is going to increase. Microgrid can play a vital role in future electricity transmission. Microgrid alone cannot fulfil the requirement its proper functioning is also required, which means that we would be able to connect or disconnect it to the main grid whenever required. Proper islanding in proper time is required to increase the reliability of the system as a whole. In this paper, the importance of microgrid connected to the main grid and the importance of islanding in proper time is analyzed during the fault in the main grid in the ETAP environment.

2019 IEEE International Conference on Environment and Electrical Engineering and 2019 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2019

Today with increase in use of microgrid, appropriate grounding design is needed for it. In this p... more Today with increase in use of microgrid, appropriate grounding design is needed for it. In this paper it is done by considering different grounding shapes for the MG. For this purpose, paper evaluates the performances of triangular, rectangular, square, L shape and T shape grounding design considering uniform and two layer soil structure. Influence of diverse designs on safety parameters such as touch voltage and step voltage are examined. Investigation is done with the help of ETAP based finite element method and for its authentification, results obtained by it are substantiated with analytical results obtained through IEEE standard 80-2013. As per the results obtained, triangular shape performs better. Also, this paper reveals the touch and step potential profiles for different shapes.

IET Science, Measurement & Technology, 2020

This study examines the sustainability of uniform as well as an optimal grounding grid (GG) desig... more This study examines the sustainability of uniform as well as an optimal grounding grid (GG) design for the microgrid (MG), in terms of variations in the top layer (TL), middle layer (ML), and bottom layer (BL) soil resistivities (ρ 1 , ρ 2 , and ρ 3 , respectively) along with change in a thickness of TL and ML. GG design is highly dependent on ρ 2 , as it helps in determining the density of conductors at grid extremities. With an increase in ρ 2 , touch voltage (TV) crosses its tolerable limit, but step voltage (SV) remains within its limit. However, with a simultaneous increase in the thickness of ML (MLT), SV also crosses its limit. For ρ 2 higher than ρ 3 , with an increase in MLT, TV, and SV increase, while in the reverse case, they decrease. For the given MLT, ρ 3 is crucial in determining GG burial depth. Validation of results is done by comparing them with the IEEE standard. Also, the optimal compression ratio of GG with an increase in MLT is analysed. TVs can be reduced to a great extent, with the application of distinctive methods of earthing (TT-GG system, TN-S-GG system, and TN-C-S-GG system) in MG. This study also reveals that an increase in GG resistance leads to a reduction in TV.

m-hikari.com

In Conventional power converters electromagnetic interference (EMI) emissions comes from the swit... more In Conventional power converters electromagnetic interference (EMI) emissions comes from the switching of a DC voltage in pulse width modulation (PWM) process. The effective way to reduce EMI in power converter is to use frequency modulation technique which modulates the originally constant switching frequency by following a certain modulation profile (i.e. sinusoidal, sawtooth, triangular, exponential, random, chaotic).This paper is dedicated to chaotic switching frequency modulation technique which is the modified form of simple frequency modulation technique and also focusing on the effectiveness of simple frequency modulation in EMI reduction as a function of the different switching modulation profiles. The simulation results show that the EMI spectrum is decided completely by the peak amplitude of PWM spectrum. Chaotic frequency modulation technique is effectively reduce it by using a variable switching frequency (modulating a base value (carrier frequency, fc)) obtained by logistic map(bifurcation technique). And also compare chaotic frequency modulation with all other different modulating profile and finally conclude that chaotic frequency-spreading gives better spectral performances and results.

2019 IEEE International Conference on Environment and Electrical Engineering and 2019 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2019

Microgrids (MG) are generally built up near the load centres. With augment of considerable number... more Microgrids (MG) are generally built up near the load centres. With augment of considerable number of MGs in the present power system, it becomes indispensable to cogently estimate the safety parameters while designing its grounding system. This is mainly due to the closeness of MG grounding to other nearby grounding systems. For this purpose, an interactive mathematical model between the two nearby grounding designs (including MG grounding) is exemplified. It shows that if mutual interaction between the two nearby grounding design are not considered then it leads to overestimation of safety parameters such as touch voltage, ground potential rise and grounding grid resistance. This causes un-necessary expenditure on safety design. Results obtained through mathematical model are substantiated by simulations results acquire through finite element method and are found to be favorable. Further, ground potential distribution profiles through FEM are also found and are in conformity with mathematical model.