مجله کیفیت و بهره وری صنعت برق ایران
سال یازدهم شماره 2 (پیاپی 27، تابستان 1401)

Financing of infrastructures and huge projects such as utility-scale solar power plants is imperative to economic development. From the perspective of investors, financing of infrastructure projects divides into two general methods including lending and partnership. One of the methods based on lending is project finance that is the focus of this study. In loan-based investing, the lower the lender's estimate of the uncertainty (risk) of future project cash flow, the more willing lender would be to invest. The method is a limited recourse; thus, the lender tendency to partnership in the finance deal depends on the reliability on future cash flow of a project. Here, we gather the results of different studies and investigate the uncertainties led to fluctuation of the expected future income of utility-scale solar power plants. Using Monte-Carlo simulations and Maximum Likelihood Estimation, the annual probability distribution of debt service coverage ratio for a 10 MW solar power plant project has been estimated during the loan term, and we use that to calculate the probability of default for each year. Then, using sensitivity analysis of financial indices to various leverages, the appropriate ratio of debt and equity in the structure of project financing are obtained. The presented method of estimating solar power plant project income can be used for other utility-scale solar power plants using specific uncertainties for each location. Our work paves the way to a more reliable decision making for lender(s) and facilitates the process of attraction of investor(s) for project company.

The purpose of this study is to explain a framework for examining the alignment of nanotechnology capabilities with the strategies of the power and energy industry with the approach of considerations and value systems to expand the existing issues and expand the use of this technology in this industry. Today, the power and energy industry is the basic infrastructure in the social, economic, and industrial development of countries and to use a wide range of technologies such as nanotechnology. It is, therefore, important to study and measure the relationship and alignment of capabilities of various technologies and strategies at the level of business units in different industries. The main components of the technology strategy in accordance with corporate strategies in industries and organizations are explained according to the identification and selection of technology, methods to achieve them, and appropriate use of various technologies, but a review of different technology development models shows that these models rarely meet social needs and value considerations. The strategic effects and competitive advantages of nanotechnology in economic, social, production, and environmental dimensions in different parts of the power and energy industry have provoked the use of this technology in this industry, making it important to study this technology in value systems. The methodology of this qualitative research was based on library studies, as well as collecting the opinions of elites and analyzing the themes derived. Using studies and analysis of the opinions of the scientific community in this field, the research finds that to explain the basic indicators for examining the alignment of nanotechnology capabilities and strategies of the power and energy industry, such as measuring compliance with work standards and effective communication between managers and stakeholders and the exchange of opinions, knowledge, and information with the value system approach, it is necessary to establish this category at the corporate levels of the power and energy industry and then at the business and operational levels in the use of nanotechnology. Nanotechnology has the potential to be used and exploited in all areas of society, and the power and energy industry, which has a competitive advantage in various fields and with a high strategic impact, is no exception. Therefore, nanotechnology can be included in development plans in this industry due to its efficacy in terms of value in meeting the challenges and needs of the power and energy industry in line with the strategies of this industry.

In this paper, the resilience of the Ardabil province power distribution network was investigated at the level of medium voltage feeders by studying the interruptions of the feeders caused by weather conditions. To do this, the weighted sum of the “number of failures due to weather condition (NFW)”, “failure time duration due to weather condition (FTW)”, and “energy not supplied due to weather condition (ENSW)” were used as an index to assess the resilience of the network. Considering the power interruptions of the last five years, for the interruptions caused by the weather conditions, the numerical value of the defined index for the electricity distribution network of Ardabil province resulted in about 20%, which indicates that the resilience of this network is about 20% less than its ideal value (it is about 80%). To reduce the defined index (increase the resilience), one of the preventive methods is to harden the equipment used in the distribution network for which the feeders that have the highest impact on the defined index were extracted as high-risk feeders to be hardened. Also, to increase the resilience of the Ardabil electricity distribution network, some suggestions have been made to harden high-risk feeders. For this purpose, a number of high-risk feeders were visited to determine possible design discrepancies (contrary to the standard design announced by Tavanir) or their incorrect implementation. By comparing the current status of the studied feeders with the design standards, solutions were provided to correct and increase the strength of these feeders (preventive action to increase resilience). The implementation of the proposed hardening methods is expected to reduce the number of interruptions (due to weather conditions), which will decrease the obtained index and increase the resilience of the network. Moreover, based on this study, it was found that wind, severe storms, rain, thunderstorms, and snow are the most common causes of outages at the level of medium voltage feeders, respectively.

Implementation of high-capacity power transmission systems in power systems is a growing trend. Among these systems, HVDC and EHVAC power transmission systems are the most popular because of their capabilities and their low investment costs over the long distances. Despite of the mentioned advantages, the reliability of the high-capacity power transmission has been a major concern for power system operators. In terms of reliability, the occurrence of an error in a high-capacity power transmission system (such as HVDCs) causes a large loss of capacity in the transmission network, which can have a major effect on the performance of this system. Therefore, reliability assessment of high-capacity power transmission systems is necessary. In this paper, the reliability level of three modern technologies (HVDC-VSC, HVDC-LCC and EHVAC in different structures) is compared. By comparing these systems, the most proper system for high-capacity power transmission from the reliability viewpoint can be selected.

In this paper, a non-isolated high step-up DC-DC converter with an interleaved structure is presented that is suitable for photovoltaic energy conversion systems. In the proposed topology, coupled inductors and the switched capacitor cells have been used to increase the output voltage. Achieving this purpose is in a situation where no extreme duty cycle or high turns ratio will be required. Due to the use of the interleaved structure and equal current division in two phases, the current ripple is reduced. Also, since the voltage stress of the switches is lower than the output voltage, selecting the low-voltage rated switches and small Rds (On) reduces the conduction loss. Other advantages of the proposed converter include providing the soft-switching conditions for the power switches and alleviating the reverse recovery problem. Recycling of the leakage energy due to the presence of the coupled inductors and no need for the clamp circuits is an important feature of the proposed converter. The experimental results, using prototype 350 W, 18 V input, and 400 V output, verify the effective performance of the proposed converter.

Multi-carrier energy systems have systematic flexibility for energy and load management. The integration of different types of energy under the concept of energy hub in multiple energy infrastructures such as electricity, natural gas, and heat in an integrated way results in the supply of load demand at a lower cost. The energy hub creates a great opportunity for energy system operators to achieve a system with higher efficiency and better performance. The profitability of energy hubs in the presence of various uncertainties, which are intensified by the presence of different types of energy carriers, is one of the issues in this field. The optimal performance of the power system depends on the optimal performance of each energy hub component. One of the most important components is combined heat and power (CHP) generation. This paper deals with the optimal operation of an energy hub in an industrial complex based on collected field data, including electrical loads and heating and cooling demands, considering electricity market prices and renewable energies such as wind and photovoltaic, as well as intelligent algorithms for responsive loads. According to the simulation results, comparing the total cost of energy in the presence and absence of responsive loads, the presence of a responsive load next to the energy hub significantly reduces the annual economic cost.