iranian journal of electrical and electronic engineering, Jun 10, 2017
This investigation deals with a mathematical model for a distribution transformer including satur... more This investigation deals with a mathematical model for a distribution transformer including saturation effect. To this end, the equations related to a three phase transformer are specified and the effect of an inter-turn fault is included. Naturally by applying an interturn fault the inductance and resistance matrix will change. Thus, unknown quantities of inductances and resistances for completing the matrix are calculated and the inputs, outputs and state variables are specified. All the equations will be rewritten in terms of state variables, subsequently saturation effect is added to the model. Finally the block diagram of the specified model based on the obtained equations are designed and the ultimate model is simulated. The saturation effect, added to the mathematical model and also the variable fault parameters are known as two significant contributions which distinguish this study from other investigations. Various results obtained from the simulation of the final model confirm the changes in the behavior of faulty transformer such as: a large circulating current flowing in the shorted turns, lower impact on terminal voltages and currents, a sudden increase in current flowing in the primary winding, asymmetrical flux distribution and inverse proportion of the fault severity and the limiting resistor.
This contribution deals with an optimal design of a brushless DC motor, using optimization algori... more This contribution deals with an optimal design of a brushless DC motor, using optimization algorithms, based on collective intelligence. For this purpose, the case study motor is perfectly explained and its significant specifications are obtained as functions of the motor geometric parameters. In fact, the geometric parameters of the motor are considered as optimization variables. Then, the objective function has been defined. This function consists of three terms i.e. losses, construction cost and the volume of the motor which should be minimized simultaneously. Three algorithms i.e. cuckoo, genetic and particle swarm have been studied in this paper. It is noteworthy that, cuckoo optimization algorithm has been used for the first time for brushless DC motor design optimization. A comparative study between the mentioned optimization approaches shows that, cuckoo optimization algorithm has been converged to optimal response in less than 250 iterations and its standard deviation is 0.03 , while the convergence rate of the genetic and particle swarm algorithms are about 400 and 450 iterations with standard deviations of 0.07 and 0.06 , respectively for the case study motor. The obtained results show the best performance for cuckoo optimization algorithm among all mentioned algorithms in brushless DC motor design optimization.
In today's world, many companies use the thermal imaging (infrared), in order to prevent failures... more In today's world, many companies use the thermal imaging (infrared), in order to prevent failures and improve the reliability of the electrical networks. In fact, the technical inspection of the electrical equipment using thermal cameras, is the most effective method for preventive defect detection. This contribution deals with, a systematic method in which, areas suspected of failure, are identified through computer-aided thermal image processing. To this end, the candidate areas are determined, using adaptive threshold and, a number of features are extracted from them. Next, using a genetic algorithm (GA), the irrelevant features are omitted. Finally, by means of a hybrid classifier, the pattern of positive and false positive areas, have been identified. This classifier can also be used as a filter, after extracting the candidate areas. This method is tested on images taken from Tehran northwest substations. As a result, applying the feature selection algorithm leads to a faster intelligent fault detection and higher Reliability, especially in widespread networks, which is known as an effective validation for the proposed method.
Reverse power (RP) phenomenon in synchronous generators may lead to severe damage to the generato... more Reverse power (RP) phenomenon in synchronous generators may lead to severe damage to the generator prime mover due to motoring action of the generator. The operation of the usual technique, which detects RP on the basis of current direction, is too slow because of utilization of intentional time delay in the relay structure. The deliberate time delay helps the relay to avoid tripping during unwanted disturbances. This paper proposes a novel angular-based scheme to detect RP in synchronous generators. For this aim, the proposed technique uses the load angle ( δ ) and the phase difference between voltage and current (θ ), as the angular quantities of the generator. Furthermore, other electrical parameters of the generator such as current and voltage are also utilized as the supplementary parameters for RP detection. Ultimately, this contribution uses the analysis of vertical component of A E ( A E Sin δ ) and also the tangential component of A I on V ( A I Cos θ ) in the generator phasor diagram for making the final decision. To verify the performance of the angular-based technique, extensive simulations are carried out on two sample systems (single machine and three machines infinite bus), under different conditions and the final results show the satisfactory performance of the proposed algorithm.
This contribution is aimed at representing the characteristics of neutral wire and also obtaining... more This contribution is aimed at representing the characteristics of neutral wire and also obtaining an optimal grounding resistance in different situations in a three-phase four-wire distribution network. To this end, various effects of the system components have been investigated on neutral wire characteristics and grounding system. On the other hand, it is concluded that, in addition to system imbalance, there are other determinative factors in which the neutral wire and grounding system have irregular characteristics. These factors include: transformer type and capacitor bank failure. The investigation also achieved an optimized grounding resistance for grounding system for different types of transformers.
International Journal of Engineering, Transactions B: Applications, 2017
This contribution deals with an optimal design of a brushless DC motor, using optimization algori... more This contribution deals with an optimal design of a brushless DC motor, using optimization algorithms, based on collective intelligence. For this purpose, the case study motor is perfectly explained and its significant specifications are obtained as functions of the motor geometric parameters. In fact, the geometric parameters of the motor are considered as optimization variables. Then, the objective function has been defined. This function consists of three terms i.e. losses, construction cost and the volume of the motor which should be minimized simultaneously. Three algorithms i.e. cuckoo, genetic and particle swarm have been studied in this paper. It is noteworthy that, cuckoo optimization algorithm has been used for the first time for brushless DC motor design optimization. A comparative study between the mentioned optimization approaches shows that, cuckoo optimization algorithm has been converged to optimal response in less than 250 iterations and its standard deviation is , ...
iranian journal of electrical and electronic engineering, 2017
This investigation deals with a mathematical model for a distribution transformer including satur... more This investigation deals with a mathematical model for a distribution transformer including saturation effect. To this end, the equations related to a three phase transformer are specified and the effect of an inter-turn fault is included. Naturally by applying an interturn fault the inductance and resistance matrix will change. Thus, unknown quantities of inductances and resistances for completing the matrix are calculated and the inputs, outputs and state variables are specified. All the equations will be rewritten in terms of state variables, subsequently saturation effect is added to the model. Finally the block diagram of the specified model based on the obtained equations are designed and the ultimate model is simulated. The saturation effect, added to the mathematical model and also the variable fault parameters are known as two significant contributions which distinguish this study from other investigations. Various results obtained from the simulation of the final model con...
The purpose of the reverse power (RP) protection is essentially to prevent severe damage to the g... more The purpose of the reverse power (RP) protection is essentially to prevent severe damage to the generator prime mover. For this aim, directional relays are usually utilised. RP condition (RPC) leads to initial oscillations of power and frequency which might exceed the RP threshold and lead to mal-operation of the relay. Therefore, assigning a time delay is essential to reduce the oscillations. However, this strategy increases the relay trip time, which leads to enhancing the motoring time and the risk of damage to the prime mover. This study proposes a novel algorithm to detect RPC in synchronous generators, based on some easily accessible quantities including active power (P), load angle (δ), internal voltage (E A ), terminal voltage (V) and the phase difference between voltage and current (θ). This scheme utilises two criterions including the sign of θ and also comparing V with tangential component of E A on V (E A Cosδ). This algorithm is independent of the size and type of load and is also capable of discriminating RPC with other potential faults. The performance of the proposed approach has been verified with Matlab software and the obtained simulation results show the fastest operation and highest reliability of the proposed technique compared to others.
Renewable energy policies emphasize both the utilization of renewable energy sources and the impr... more Renewable energy policies emphasize both the utilization of renewable energy sources and the improvement of energy efficiency. Over the past decade, built-in photovoltaic (BIPV) technologies have mostly focused on using photovoltaic ideas and have been shown to aid buildings that partially meet their load as sustainable solar energy generating technologies. It is challenging to install conventional photovoltaic systems on curved facades. In this research, elastic solar panels assisted by flexible photovoltaic systems (FPVs) were developed, fabricated, and analyzed on a 1 m2 scale. A flexible structure on a flat, hemispherical, and cylindrical substrate was studied in real terms. Using the LabVIEW application, warm and dry climate data has been recognized and transmitted online. The results showed that when installed on the silo and biogas interfaces, the fill factor was 88% and 84%, respectively. Annual energy production on the flat surface was 810 kWh, on the cylindrical surface wa...
iranian journal of electrical and electronic engineering, Jun 10, 2017
This investigation deals with a mathematical model for a distribution transformer including satur... more This investigation deals with a mathematical model for a distribution transformer including saturation effect. To this end, the equations related to a three phase transformer are specified and the effect of an inter-turn fault is included. Naturally by applying an interturn fault the inductance and resistance matrix will change. Thus, unknown quantities of inductances and resistances for completing the matrix are calculated and the inputs, outputs and state variables are specified. All the equations will be rewritten in terms of state variables, subsequently saturation effect is added to the model. Finally the block diagram of the specified model based on the obtained equations are designed and the ultimate model is simulated. The saturation effect, added to the mathematical model and also the variable fault parameters are known as two significant contributions which distinguish this study from other investigations. Various results obtained from the simulation of the final model confirm the changes in the behavior of faulty transformer such as: a large circulating current flowing in the shorted turns, lower impact on terminal voltages and currents, a sudden increase in current flowing in the primary winding, asymmetrical flux distribution and inverse proportion of the fault severity and the limiting resistor.
This contribution deals with an optimal design of a brushless DC motor, using optimization algori... more This contribution deals with an optimal design of a brushless DC motor, using optimization algorithms, based on collective intelligence. For this purpose, the case study motor is perfectly explained and its significant specifications are obtained as functions of the motor geometric parameters. In fact, the geometric parameters of the motor are considered as optimization variables. Then, the objective function has been defined. This function consists of three terms i.e. losses, construction cost and the volume of the motor which should be minimized simultaneously. Three algorithms i.e. cuckoo, genetic and particle swarm have been studied in this paper. It is noteworthy that, cuckoo optimization algorithm has been used for the first time for brushless DC motor design optimization. A comparative study between the mentioned optimization approaches shows that, cuckoo optimization algorithm has been converged to optimal response in less than 250 iterations and its standard deviation is 0.03 , while the convergence rate of the genetic and particle swarm algorithms are about 400 and 450 iterations with standard deviations of 0.07 and 0.06 , respectively for the case study motor. The obtained results show the best performance for cuckoo optimization algorithm among all mentioned algorithms in brushless DC motor design optimization.
In today's world, many companies use the thermal imaging (infrared), in order to prevent failures... more In today's world, many companies use the thermal imaging (infrared), in order to prevent failures and improve the reliability of the electrical networks. In fact, the technical inspection of the electrical equipment using thermal cameras, is the most effective method for preventive defect detection. This contribution deals with, a systematic method in which, areas suspected of failure, are identified through computer-aided thermal image processing. To this end, the candidate areas are determined, using adaptive threshold and, a number of features are extracted from them. Next, using a genetic algorithm (GA), the irrelevant features are omitted. Finally, by means of a hybrid classifier, the pattern of positive and false positive areas, have been identified. This classifier can also be used as a filter, after extracting the candidate areas. This method is tested on images taken from Tehran northwest substations. As a result, applying the feature selection algorithm leads to a faster intelligent fault detection and higher Reliability, especially in widespread networks, which is known as an effective validation for the proposed method.
Reverse power (RP) phenomenon in synchronous generators may lead to severe damage to the generato... more Reverse power (RP) phenomenon in synchronous generators may lead to severe damage to the generator prime mover due to motoring action of the generator. The operation of the usual technique, which detects RP on the basis of current direction, is too slow because of utilization of intentional time delay in the relay structure. The deliberate time delay helps the relay to avoid tripping during unwanted disturbances. This paper proposes a novel angular-based scheme to detect RP in synchronous generators. For this aim, the proposed technique uses the load angle ( δ ) and the phase difference between voltage and current (θ ), as the angular quantities of the generator. Furthermore, other electrical parameters of the generator such as current and voltage are also utilized as the supplementary parameters for RP detection. Ultimately, this contribution uses the analysis of vertical component of A E ( A E Sin δ ) and also the tangential component of A I on V ( A I Cos θ ) in the generator phasor diagram for making the final decision. To verify the performance of the angular-based technique, extensive simulations are carried out on two sample systems (single machine and three machines infinite bus), under different conditions and the final results show the satisfactory performance of the proposed algorithm.
This contribution is aimed at representing the characteristics of neutral wire and also obtaining... more This contribution is aimed at representing the characteristics of neutral wire and also obtaining an optimal grounding resistance in different situations in a three-phase four-wire distribution network. To this end, various effects of the system components have been investigated on neutral wire characteristics and grounding system. On the other hand, it is concluded that, in addition to system imbalance, there are other determinative factors in which the neutral wire and grounding system have irregular characteristics. These factors include: transformer type and capacitor bank failure. The investigation also achieved an optimized grounding resistance for grounding system for different types of transformers.
International Journal of Engineering, Transactions B: Applications, 2017
This contribution deals with an optimal design of a brushless DC motor, using optimization algori... more This contribution deals with an optimal design of a brushless DC motor, using optimization algorithms, based on collective intelligence. For this purpose, the case study motor is perfectly explained and its significant specifications are obtained as functions of the motor geometric parameters. In fact, the geometric parameters of the motor are considered as optimization variables. Then, the objective function has been defined. This function consists of three terms i.e. losses, construction cost and the volume of the motor which should be minimized simultaneously. Three algorithms i.e. cuckoo, genetic and particle swarm have been studied in this paper. It is noteworthy that, cuckoo optimization algorithm has been used for the first time for brushless DC motor design optimization. A comparative study between the mentioned optimization approaches shows that, cuckoo optimization algorithm has been converged to optimal response in less than 250 iterations and its standard deviation is , ...
iranian journal of electrical and electronic engineering, 2017
This investigation deals with a mathematical model for a distribution transformer including satur... more This investigation deals with a mathematical model for a distribution transformer including saturation effect. To this end, the equations related to a three phase transformer are specified and the effect of an inter-turn fault is included. Naturally by applying an interturn fault the inductance and resistance matrix will change. Thus, unknown quantities of inductances and resistances for completing the matrix are calculated and the inputs, outputs and state variables are specified. All the equations will be rewritten in terms of state variables, subsequently saturation effect is added to the model. Finally the block diagram of the specified model based on the obtained equations are designed and the ultimate model is simulated. The saturation effect, added to the mathematical model and also the variable fault parameters are known as two significant contributions which distinguish this study from other investigations. Various results obtained from the simulation of the final model con...
The purpose of the reverse power (RP) protection is essentially to prevent severe damage to the g... more The purpose of the reverse power (RP) protection is essentially to prevent severe damage to the generator prime mover. For this aim, directional relays are usually utilised. RP condition (RPC) leads to initial oscillations of power and frequency which might exceed the RP threshold and lead to mal-operation of the relay. Therefore, assigning a time delay is essential to reduce the oscillations. However, this strategy increases the relay trip time, which leads to enhancing the motoring time and the risk of damage to the prime mover. This study proposes a novel algorithm to detect RPC in synchronous generators, based on some easily accessible quantities including active power (P), load angle (δ), internal voltage (E A ), terminal voltage (V) and the phase difference between voltage and current (θ). This scheme utilises two criterions including the sign of θ and also comparing V with tangential component of E A on V (E A Cosδ). This algorithm is independent of the size and type of load and is also capable of discriminating RPC with other potential faults. The performance of the proposed approach has been verified with Matlab software and the obtained simulation results show the fastest operation and highest reliability of the proposed technique compared to others.
Renewable energy policies emphasize both the utilization of renewable energy sources and the impr... more Renewable energy policies emphasize both the utilization of renewable energy sources and the improvement of energy efficiency. Over the past decade, built-in photovoltaic (BIPV) technologies have mostly focused on using photovoltaic ideas and have been shown to aid buildings that partially meet their load as sustainable solar energy generating technologies. It is challenging to install conventional photovoltaic systems on curved facades. In this research, elastic solar panels assisted by flexible photovoltaic systems (FPVs) were developed, fabricated, and analyzed on a 1 m2 scale. A flexible structure on a flat, hemispherical, and cylindrical substrate was studied in real terms. Using the LabVIEW application, warm and dry climate data has been recognized and transmitted online. The results showed that when installed on the silo and biogas interfaces, the fill factor was 88% and 84%, respectively. Annual energy production on the flat surface was 810 kWh, on the cylindrical surface wa...
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