Economic evaluation of transformer selection in electrical power systems (original) (raw)
Economic Evaluation of Transformer Selection in Distribution Systems
This paper presents an approach to determine the total owning cost (TOC) of transformers. Different assumptions are introduced by discounting the transformer cost and/or the losses cost, using either A and B loss coefficients or the idea of annuity factor. Moreover, the paper presents a comparative study between different cases under different presumptions to evaluate the transformer's TOC. The obtained results confirm that the proposed approach equips the decision-maker with valuable and trustable criteria to select the proper transformer(s) based on the proposed practical cost criteria. The presumptions of the proposed cost criteria influence economic evaluation. The TOC of the transformer is also illustrated. Finally, the proposed approach cost criteria were illustrated through a numerical example. The obtained results have been summarized and discussed.
Economic Criteria in Competition for Deliveries of Power Transformers
Latvian Journal of Physics and Technical Sciences, 2009
In the article, economic estimation is given for the measures on purchase of new power transformers and replacement of the existing ones for the Latvian power system (Latvenergo). The optimal choice for the purchases and deliveries of new power transformers is considered as a task of choosing among suppliers on a competitive basis (through tenders). As the objective function for the estimation, the total annual discounted costs for the user of a transformer during its service life are taken. A simplified estimation model is proposed, based on which the calculations of tenders have been done.
Economical analysis for efficient transformers projects
2010
This paper presents results for the economical analysis of efficient monophase transformers when used instead of standard transformers made at the High Voltage Laboratory if Federal University of Itajubá (LAT-EFEI). The analysis was made using capitalization rules based into two wages cycles, as recommended by Brazilian Electrical Energy Agency-ANEEL. In addition, it is also discussed, briefly, a comparison made with the traditional method using the present value of transformer losses costs. Finally, authors propose a methodology to study the application of efficient transformers to replace the ones standardized by Brazilian normative association, ABNT.
Decision support system for evaluating transformer investments in the industrial sector
This paper presents a decision support system (DSS) for evaluating transformer investments in the industrial sector. The DSS evaluates transformer bids based on the total owning cost (TOC). Among all transformer offers, the most cost-effective and energy-efficient transformer is the one with the lowest TOC. The DSS compares the selected offer with the other competing offers. Moreover, the proposed DSS deals with the uncertainty of the values in the TOC formula by performing a sensitivity analysis.
Distribution transformer cost evaluation methodology incorporating environmental cost
As system investment and energy costs continue to increase, electric utilities are increasingly interested in installing energy-efficient transformers at their distribution networks. The cost evaluation of transformers is based on total owning cost (TOC) method that includes transformer purchasing price and cost of transformer losses. Similar to energy cost, greenhouse gas (GHG) emissions are also assigned a price by energy markets. That is why this study proposes an innovative distribution transformer cost evaluation methodology (DTCEM) by introducing the environmental cost (EC) into the conventional TOC method. This EC is due to GHG emissions associated with supplying transformer losses. The proposed method is applied for economic evaluation of distribution transformers for the Hellenic power system and the results are compared to the conventional TOC, indicating the importance of incorporating EC into transformer economic evaluation. A sensitivity analysis is carried out, investigating the impact of various parameters involved in the proposed DTCEM.
Distribution transformers represent a significant cost to electric utilities, both as a capital
2004
Distribution transformers represent a significant cost to electric utilities, both as a capital investment and as an ongoing operating expense. A survey of seven 2003 FERC Form 1 filings shows that distribution transformers can account for approximately 9 to 20% of total distribution capital spending in a year. Productivity tools that help to minimize transformer total owning costs and increase overall asset utilization can make a significant impact on a distribution utility’s bottom line. The Distribution Systems Testing, Application, and Research (DSTAR) utility consortium commissioned the development of the Transformer Owning Cost Software (TOCS) tool for analyzing and comparing the total owning cost of distribution transformers.
Economic Benefit Analysis of 220 kV Energy-saving Power Transformer
Energy and Power Engineering, 2013
Power transformer serves as one of the most widely used electrical equipments in power grid. During the operation, terrible losses are produced. With the development of loss reduction technology of power transformers, in order to save energy saving and reduce emissions, the old power transformer should be replaced. The paper summarizes the main method to reduce the losses of power transformers and brings up the improved Total Owning Cost (TOC) algorithm, which applies to 220 kV power transformers' comprehensive benefit analysis. Using the improved Total Owning Cost (TOC) algorithm, based on today 220 kV energy-saving power transformer manufacturing level, the economic benefits of new energy-saving power transformer and the return period of investment are analyzed. Finally, combined with energy-saving effect, the appropriate replacement proposal of 220 kV power transformers has been given.
An overview on power transformer management: Individual Assets and Fleets
2012 Sixth IEEE/PES Transmission and Distribution: Latin America Conference and Exposition (T&D-LA), 2012
A Power Transformer is an efficient and reliable machine that is designed and built to ensure a long useful life under normal operation. However, among the total number of operative power transformers installed in networks around the world, there are many aged units, which are approaching to the state of final failure. This situation of simultaneous aging becomes a major problem, and its proper solution is critical for the electric utilities because their financial performance and economic viability are unavoidably dependent on the reliability of this equipment. In this regard, this paper presents an overview on the optimal management of a power transformer fleet. The review is focused on a methodological scheme oriented to the assessment of the transformer risk index and its two main components: the probability of failure index and the post-failure consequence index.
IEEE Transactions on Power Delivery
This paper defines a probabilistic, life-cycle loss evaluation method to evaluate the total ownership cost of power transformers that are obliged to exclusively serve large wind plants. The method that is introduced responds to the ongoing efforts of developing risk and cost-based decision-making processes in today's competitive and dynamic energy markets. Therefore, capitalizing the losses and, consequently, the ownership cost of transformers, serving intermittent wind energy sources, entails a probabilistic approach that integrates the financial and technical characteristics as well as the uncertainties of wind energy generation.
Environmental cost of distribution transformer losses
Improvements in energy efficiency of electrical equipment reduce the greenhouse gas (GHG) emissions and contribute to the protection of the environment. Moreover, as system investment and energy costs continue to increase, electric utilities are increasingly interested in installing energy-efficient transformers at their distribution networks. This paper analyzes the impact of the environmental cost of transformer losses on the economic evaluation of distribution transformers. This environmental cost is coming form the cost to buy GHG emission credits because of the GHG emissions associated with supplying transformer losses throughout the transformer lifetime. Application results on the Hellenic power system for 21 transformer offers under 9 different scenarios indicate that the environmental cost of transformer losses can reach on average 34% and 8% of transformer purchasing price for high loss and medium loss transformers, respectively. That is why it is important to incorporate the environmental cost of transformer losses into the economic evaluation of distribution transformers.
Economic analysis of efficient distribution transformer trends
1998
This report has been reproduced directly from the best available copy. Available to D E and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831; prices available from (615) 576-8401. FTS 626-8401.
Economic criteria for optimizing the number and load factor of mining transformers
Mining of Mineral Deposits
Purpose. This article discusses how to choose the optimal number and load factor, respectively the economic power in the first year of mining power transformers operation. The analysis is carried out based on technical-economic criteria. In this regard, two economic criteria are proposed for a detailed analysis, namely the minimum updated total expenses criterion and the minimum power and energy losses criterion. Methods. For determining the number and the optimal load factor, the paper presents mathematical models for the two economic criteria used. The results obtained by the presented methods are simulated using Matlab for several series of underground mining transformers. Also, it is assumed that the load remains constant over the year. Findings. The article confirms the possibility of using the analyzed economic criteria for establishing the optimal number of mining transformers as well as the optimal load factor, respectively the optimal power for the first year of operation. The difficulty of the research is related to the loss time assessment. Also, the paper presents the performed comparative analysis of the two implications. Originality. This research provides a novel approach, by the detailed presentation of the two criteria used for describing the objective functions which have to be minimized in order to gain the optimum, referring strictly to mining transformers, which represents a novelty for power engineering in mining. Practical implications. The methods described in the article can be successfully used in the case of new mining power networks which are going to be designed, and in the case of those currently in operation. Economic criteria analysed also provide results for the economical regime of mining transformers which corresponds to minimum energy loss. Therefore, this case also results in significant energy savings, i.e. lower economic criteria used.
IJSES, 2023
It's a fine business move, if prior to investing in transformers, we analytically identify the most cost-effective and energy-efficient transformer. In the total owning cost (TOC) economic analysis, it is helpful to determine how sensitive the TOC is to several factors of interest, so that the proper attention may be given to them in the decision process. Also, the manufacturers become better equipped to engineer each design to the unique situation of each customer; and the utilities are then able to compare multiple designs so as to find the optimum for their peculiar load profile. Usually, in sensitivity analyses, when the load factor (LF) is being varied to observe the trend in the ∆TOC (TOC difference between the transformer offers of interest); all other input variables of the TOC model are assumed constant. However, it is herein argued that any transformer TOC what-if analysis whose approximations wholly undermine the load pattern, to vary LF independent of the load related variables; could significantly affect the capitalization of losses, which may result in errors in judgment regarding the future uncertainties and relative importance among the input variables of the TOC model. This article is therefore an attempt to investigate this error in assumption/procedure, in the light of fostering sounder judgment towards ultimately maximizing energy savings at the lowest TOC, as long as the transformer is concerned. The sensitivity level with a comprehensive LF variation was observed in this study to at least double that obtained otherwise, and the magnitude and sense of the ∆TOC were significantly influenced by the peculiarity of the load dynamics.
A Further Look into the Service Lifetime Cost of Solar Photovoltaic Energy Transformers
2021 Southern African Universities Power Engineering Conference/Robotics and Mechatronics/Pattern Recognition Association of South Africa (SAUPEC/RobMech/PRASA), 2021
In this day and age, there is a proliferate concern from all governments across the globe to barricade the environment from the greenhouse gases, which absorb infrared radiation. As a result, solar photovoltaic (PV) energy has been an expeditiously growing renewable energy source and will eventually undertake a prominent role in the global energy generation. The selection and purchasing of energy efficient transformers which meet the operational requirements of the solar photovoltaic energy generation plants then becomes a part of the Independent Power Producers (IPP's) investment plan of action. Taking these into account, this work proposes a novel procedure that put into effect the intricate financial analysis necessitated to precisely evaluate the transformer service lifetime no-load and load loss factors. This procedure correctly set forth the transformer service lifetime loss factors as a result of solar PV plant's sporadic generation profile and related levelized costs of electricity into the computation of the transformer's total ownership cost. The results are then critically compared with the conventional transformer total ownership cost (TCO), and demonstrate the significance of the sporadic energy generation nature of the solar PV plant on the total ownership cost. The findings indicate that the latter play a crucial role for developers and Independent Power Producers (IPP's) in making the purchase decision during a tender bid where competing offers from different transformer manufactures are evaluated. Additionally, the susceptibility analysis of different factors engrossed in the transformer service lifetime cost is carried out, factors including the levelized cost of electricity, solar PV plant's generation modes and the loading profile are examined.
In this paper existing electrical distribution network of Prem Nagar Railway colony in Jabalpur with specific reference to Transformer losses and Contract Demand has been studied.It includes proposal of revision in transformer capacity to minimize technical losses. This work undertakes techno-commercial study and proposes additions/ alterations/modifications for loss reduction/improvement in capacity of existing Distribution Transformers.The cost of proposed works has been compared with the cost of losses for establising commercial viability of alterations/additions for adoption.The work also includes optimization of Contract Demand which reduces the billing outlay for existing as well as restructured/suggested system installation.
Analysis of the Green Power Transition on Optimal Power Transformer Designs
Periodica Polytechnica Electrical Engineering and Computer Science, 2015
The main intent of the power transformer design optimization in the tendering stage is to find those mechanical and electrical parameters, which minimize the machines' total cost of the ownership by reducing the different power losses and the manufacturing costs. To find the optimal transformer design parameters and make them harmonize with the economic constraints is a labour intensive task, because these quantities are linked with complex trade-off and physical functions. The capitalization of the load and no-load losses facilitate this process. The focus of this paper is to examine the sensitivity of the design parameters from the capitalization factors. Three different scenarios are presented and analysed in this paper, where the transformers are connected to various stochastic or schedulable green power generation resources. This paper presents the optimal transformer design's dependency from the various scenarios of different green power generation resources.