مجله کیفیت و بهره وری صنعت برق ایران
سال هشتم شماره 2 (پیاپی 16، پاییز 1398)

In this paper, a microgrid including a solar panel, a battery energy storage system and a diesel generator as the backup source are optimally is designed. The microgrid is considered as a part of a distribution network, that could be considered as local area. As microgrids can operate in grid-connected mode, the proposed algorithm investigates the minimization of the distribution network power loss, the amount of imported power from the utility and the curtailed load in case of emergency. The main purpose of the proposed algorithm is to minimize the overall investment, replacement and operation and maintenance costs for a microgrid. This article suggests a Lightning Attachment Procedure Optimization Algorithm to optimally design the problem of sitting and scheduling of microgrids in distribution systems. Both problems are solved simultaneously. The proposed approach is applied on 33-bus test system, and the results are discussed. Fast convergence, best global answer finding, and robustness are the characteristics of the proposed method, which are concluded from the results and discussion.

In the real world, many goods and services are practically not produced under the conditions of full competition, and most public utilities such as water, electricity, gas, and telephone are operated under monopoly conditions, among which the electricity industry has a special place regarding the price of energy carriers in the country, subsidies from the government, limitation of fossil resources, annual consumption growth of various types of energy carriers in Iran, technical and economic disadvantages of energy consumption, and environmental problems caused by inappropriate and inefficient fuel consumption, optimizing energy consumption in the country has become a necessity. Therefore, the purpose of this study was to evaluate and prioritize the factors affecting the optimization of electrical energy of industrial customers of Semnan Regional Electric Company with a combination of an exploratory hybrid approach. The research method is a combination of exploratory sequencing method. The research participants in the interview section included 35 representatives and specialists in the field of electronics and electronics as potential contributors through a targeted sampling of key experts and theoretical saturation technique. In a small section, a questionnaire with 54 questions was designed and distributed between 35 experts. In this section, the Fuzzy Delphi method was used to reach a consensus among experts on 6 dimensions of management, information, financial, political/legal, cultural/organizational, and technical/technological. In the Fuzzy Delphi method, after three phases experts came into a conclusion and 30 sub-criteria were confirmed. Then, the fuzzy ANP-DEMATEL combination approach was used. Using the fuzzy DEMATEL method, the relationships between factors and their impact were found to be the most effective technical barriers and the policy of conservation / legal regulation as the most influential factor. Then, ANP process, the weight of the calculated factors and their significance were determined. In the first case, technical barriers were the most important (with a weight of 266.0) and management barriers of the least importance (weighted 113.0).

Eccentricity fault is one the most common fault types of disk-type permanent magnet machines, which could lead to devastating effects. Unfortunately, most of the previous works have studied this fault and its detection techniques for slotted structure with common winding. Therefore, in this paper, the effects of eccentricity faults on the performance of single-sided slotted, single-sided slotless, double-sided slotted, and double-sided slotless structures, all of which are toroidal wounded, are studied. For this purpose, for each of these structures, full load and absolute no-load conditions at three healthy, dynamic eccentricity, and static eccentricity states have been modeled by using 3D finite element transient analysis. Various performance characteristics, i.e. total input current, current in parallel paths, coils circulating current, total flux linkage, flux linkage of each coil, torque, and axial force on rotor, have been extracted.  The eccentricity faults effects on the performance of these motors have been studied through the analysis and comparison of these characteristics. According to the obtained results, using slotless stator and double-sided structure would lead to great reduction of the undesired effects of these faults. Moreover, it will be shown that conventional detection techniques of eccentricity faults may not be effective for some structures.

Today, the increased use of distributed generation units along with the storage devices as well as telecommunication enhancements have led to the formation of microgrids and thus multi-microgrids (MMGs). In this type of networks, the probability of the fault occurrence in different places of the network is not out of expectation, and it can be argued that the failure of the network not only increases the losses, reduces the efficiency and increases the outage, but also, it disrupts network operation and makes the operation process of the system more complex. From this point of view and with the aim of filling the existing research gaps, in this paper a comprehensive energy management strategy for operation of multi-microgrids considering uncertainty of the fault occurrence in the different part of the system is presented. In the proposed comprehensive energy management strategy, a novel problem formulation for both self-healing and cost effective operation, as well as the network operators’ relationship are considered. In this situation, at first, an appropriate method is proposed to address the contingency faults which can be occurred in the different places of the network, then intended energy management strategy is implemented. The proposed methodology is implemented in the MATLAB software environment and its effectiveness is demonstrated in the modified reliability based test system with considering some other traditional methods.

Electricity demand forecasting is one of the most important factors in the planning, design, and operation of competitive electrical systems. However, most of the load forecasting methods are not accurate. Therefore, in order to increase the accuracy of the short-term electrical load forecast, this paper proposes a hybrid method for predicting electric load based on a deep neural network with a wavelet transform and input selection. Based on the entropy function. Also, in order to demonstrate the strength of the proposed method, the PJM electricity market and one of the Kerman substations load data in 1395 were used and the results of which emphasized the efficiency of the proposed method in predicting the electric load for production planning And distribution.

This paper proposed a new hybrid filter, including an active filter based on a current source converter (CSC) and a modified capacitor bank with a passive filter structure for reduce harmonic and reactive power compensation problems. This new structure, based on separating high-frequency and low-frequency components of the reference current idea can affect the performance of both filters and increase the efficiency of the hybrid filter. The low frequency components are applied to the active filter and high frequency components applied to the modified capacitor bank. The passive filter extractor unit, based on received information from the designer can compensate the network reactive power and selectively higher-order harmonics simultaneously. This idea reduces the current network harmonics to desired level of IEEE519-2014 standard and compensates the network reactive power, while it can reduce the capacity, cost, and loss of the current source converter. In order to verify the performance of the proposed filter, a typical distribution network with a non-linear load is studied in PSCAD/EMTDC environment. The obtained results show that the proposed idea has a considerable flexibility for the filter and increases its efficiency.