فصلنامه روشهای هوشمند در صنعت برق
پیاپی 54 (تابستان 1402)

The brushless doubly fed induction generator (BDFIG) is one of the main members of doubly fed electrical generators which has come close to commercialization in recent years. This generator has some of outstanding features of squirrel cage induction generator and conventional synchronous generator, and at the same time, it requires a partially rated converter. One of the major challenges in the evolution of this generator is the problem of controlling it and the necessity of having a suitable and efficient controller to stabilize the generator in the operating speed range. Therefore, in this paper, a comprehensive vector control scheme based on nonlinear control methods is proposed. Accordingly, a reference model controller fulfills the control of rotor speed. In addition, for simultaneous control of reactive power and torque, a combined approach based on sliding mode and PI controllers are used. The simulation results show in presence of the mentioned control structure, the dynamic response of system in different conditions such as change of mechanical input power and reference speed variation is much more appropriate than when a linear controller is used.

With the addition of distributed generation resources to the structure of distribution networks, at the time of the fault, the amount and direction of flow through the main and backup protections changes and disrupts the coordination between them. Synchronous generator-based sources, meanwhile, are more sensitive to error fixing times and their stability may be compromised. Since the troubleshooting time depends on the performance of the protection system, this paper proposes the most suitable protection combination for systems with synchronous generators by examining the types of combinations for protection elements (relay-relay, relay-recloser and recloser-fuse). Slowly On the other hand, this paper presents a solution by which, while maintaining the stability of the first oscillation of synchronous generators in the distribution network, the coordination between the main protection and the backup in the event of an error and in the presence of these sources can be maintained. There is no need to change or redesign the protection system in this solution. The proposed method, by activating the instantaneous characteristic along with the characteristic curve of the relay in the system, was able to establish coordination between the protections and transient stability of the synchronous generators in the distribution system for a penetration coefficient of 0 to 100%. The results of the implementation of the proposed method on the standard 33-bus IEEE test system in the ETAP software environment confirm its capability.

This paper presents energy and load management by using a scenario-based assessment strategy for the optimal scheduling of a proposed hub by considering uncertain parameters (electricity price and wind turbine output power). Carbon capture utilization and storage (CCUS) technology and demand response programs (DRP), especially the time of use (TOU) program are investigated. Carbon technology helps to overcome pollution issues, on the one hand, and earn revenue for the power system, on the other hand. Also, the demand response programs help to reduce costs and pollution, make the load curve flatter, increase the reliability and power quality of the network. The proposed energy hub consists of various renewable and non-renewable distributed energy resources, as well different planning horizons, include deterministic and robust ones. The presented hub consists of diverse energy sectors like electricity, heat, cooling, gas, and water at the input and output sections. The problem is then modeled as a MILP and solved using the CPLEX solver in GAMS software. Epsilon constraint method with the fuzzy satisfying approach is used to obtain and select the best solution. The final results show that the cost and the pollution in the robust planning experience the increment by about 12.3% and 1.9% respectively in comparison to deterministic, as well, demand response programs and CCUS technology are had a significant impact on the objective functions. In addition, the load curve has become flatter and the reward by using a carbon system is obtained for the hub.

Proper management of electrical energy in the electricity distribution network is one of the main issues of network operation that high impact of reducing operating costs, reducing network losses, increasing the quality of updates, increasing customer satisfaction and etc. can have achieving these goals is possible when the elements of the distribution network act in coordination and awareness of each other. This paper considers this awareness among home subscribers, car charging parking lots and the network operating company has been taken and its benefits have been explored. A two-stage model of energy management in the distribution network is presented. The first stage is related to home energy management in the presence or absence of a load response program, taking into account tastes. Subscribers' personalization is done to bring the results closer to the real world then based on the information sent from these subscribers and determining the residential load profile of the network, electric car charging parking operators to manage according to their limitations electric vehicle to improve both charging costs and network operation parameters. Unlike traditional charging methods, in this method does not require a full charge of car batteries and only the final limit of the battery charge level in terms of energy required for drivers' future trips will be determined, and charging operations will be performed using the discrete charge rate. The results of a review of various case studies applied to a 37-bus distribution network shows that the proposed method has a high capability. In providing customer satisfaction, improving network operation parameters and reducing charging costs and meeting the needs of car drivers will had. This method can pave the way for expanding the level of vehicle penetration in distribution networks and the benefits of the load response program and smart charging maximizes productivity.

Due to the rapid growth of wind energy and its significant effect on the power grid, fault-tolerant in wind turbines is considered crucial to increase their reliability and availability levels. This paper presents a fault-tolerant technique for multiple open-switch faults in a six-phase AC-DC converter as the most vulnerable components of the wind turbine system. The proposed fault-tolerant technique uses the redundancy mode of six-phase space vectors in space vector pulse width modulation (SVPWM) and changes the switching signals in fault sectors, replacing the desired space vector with another space vector to avoid creating an undesired space vector. The main advantage of this technique is that, without adding any legs, switches, or triode for alternating currents (TRIAC) to the converter circuit, and without the need for complex calculations, the open switch faults are tolerated and the value of overcurrent and total harmonic distortion (THD) caused by the open switch faults on the healthy and faulty phases are reduced. Finally, the proposed fault-tolerant technique is evaluated by MATLAB simulation and the results of this simulation show its effectiveness.

Transmission system reliability is an important issue in transmission network expansion planning (TNEP). Most of papers and research about TNEP employed N–1 safe criterion to formulate the transmission reliability, while a few of them have considered load shedding (LS) index to meet the required reliability of consumers for electric demand. Thus, an economic evaluation is necessary to clear which of these reliability criteria is more appropriate for transmission expansion planning studies. This paper tries to compare these reliability indices to each other and show that which of them are more economic and better for expansion planning of a transmission system. The aim is to compromise between transmission lines and substations expansion cost, network losses, and system reliability considering maintenance and repair expenses as well as replacement cost of timeworn lines. To formulate the network reliability, first deterministic reliability criterion of N–1 was employed and embedded in the problem formulation and results were discussed, then N–1 criterion was replaced by probabilistic reliability index of load shedding in TNEP formulation and the results were compared with results of first model. Both of TNEP models are tested on well known as Garver’s 6-bus network and IEEE reliability 24-bus test system (IEEE RTS).

In this study, an effective and efficient algorithm for detection a saliency map is presented based on the modeling of the rapid response of the human visual system to changes in the intensity, texture and color. Some cases such as inspiration from performance of human visual system, requiring no training, reduce number of image colors, reduce color channels and Proper use of the least texture information in this algorithm have increased its efficiency. In the proposed method in the first step , Due to sensitivity of the human visual system to higher contrast signals, only higher contrast channel has been used to extract the color saliency map, Then the intensity saliency map as well as the texture saliency map are extracted using the intensity component in lab color space using Simple cell computational model of the visual cortex and finally, with the perfect combination of the saliency maps of the color, the intensity, and the texture, object saliency map is obtained. The proposed method and existing methods have been tested on MSRA10K and ECSSD databases. The results of the implementations show that the proposed hybrid algorithm for the detection saliency map using the dominant color and texture features, On the ECSSD database, the mean absolute error, F-measure score and the area under the ROC curve are 0.173, 0.789 and 0.891, respectively, and on the MSRA10K database are 0.178, 0.790 and 0.919, respectively, compared to other models, it indicates better performance of the proposed method than other methods.

The conventional Tracking-Learning-Detection (TLD) algorithm is sensitive to illumination change and clutter and low frame rate and results in drift even missing. To overcome these shortcomings and increase robustness, by improving the TLD structure via integrating mean-shift and co-training learning can be achieved better results undergo low frame rate (LFR) condition and the robustness and accuracy tracking of the TLD structure increases. Because of, the Mean-Shift tracking algorithm is robust to rotation, partial occlusion and scale changing and it is simple to implement and takes less computational time. On the other, the co-training learning algorithm with two independent classifiers can learn changes of the target features in during the online tracking process. Therefore, the extended structure can solve the problem of lost object tracking in LFR videos and other challenges simultaneously. Finally, comparative evaluations of the proposed method to other top state-of-the-art tracking algorithms under the various scenarios from the TB-100 known dataset, demonstrate the superior performance of the proposed algorithm compared to other tracking algorithms in terms of tracking robustness and stability performance. Finally, the proposed structure based on the TLD architecture, in scenarios with the various challenges mentioned, will improve on average about 33% of the results, compared to the traditional TLD algorithm.

In this paper, the improvement of the radiation pattern and the properties of multi-band trapezoidal fractal antenna with self-complementary layers have been investigated. The antenna is excited by a microstrip feed-line with two sub-layers to increase bandwidth and improve the radiation pattern. The dual-layered complementary arrangement has had positive effects on the resonance frequencies and improved the properties of the radiation patterns. This antenna offers a good efficiency, suitable bandwidth, and radiated pattern in a designed resonance frequency. Six bands (S11<-15 dB), with center frequencies of f1=0.9 GHz, f2=1.57 GHz, f3=1.85 GHz, f4=2.15 GHz, f5=2.5 GHz and f6=3.5 GHz are obtained within the band of (0.5-4) GHz. This antenna offers good efficiency which changes from 70% to 95%. The measurement results clearly confirm the simulation results

In this paper, a 2 GHz counter is implemented on a low-cost XC6SLX9-2FTG256C field-programmable gate array (FPGA) chip from the Spartan6 family with a 500 ps resolution. Since the hardware resources contained in this chip are not sufficient to implement this design, and also the inherent delays of the hardware resources inside the chip are about few nanoseconds, achieving this accuracy is very important. The architecture used in this research is based on the phase difference clocks that has been implemented after optimization. To achieve this accuracy, it is necessary to design and implement counters with high clock frequency, low jitter and low skew, without dependence on hold time and setup time. Alternative hardware resources have also been used to compensate for the lack of hardware resources required to implement routing clocks.