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In a response to economic growth, electric power utilities installed many electric power facilities to meet power demand. However, these facilities have aged and should be replaced in the near future. Moreover, the demand is said to constantly increase. Therefore, it is necessary to partially upgrade facilities. In this paper, we upgrade transformers with one of the financial engineering techniques...
The article deals with the method for the assessment of the fiber-optic communication line reliability taking into account the effect of the optical fiber tension, the temperature influence and the built-in diagnostic equipment errors of the first kind. The reliability is assessed using the theory of Markov chains and probabilistic mathematical modeling. The reliability is assessed in terms of the...
Nowadays, the population of installed transformer in PT PLN (Persero) Transmisi Jawa Bagian Barat is 305 units which consists of many variations of manufacturers and types. It consists of 21 manufacturers and 38 types along with different operational age from the young age transformers (under 20 years) until the old age transformers (more than 20 years). It means, TJBB needs different strategy for...
A modular UPS system is generally presented as having a much higher level of availability than a monolithic, double conversion, on-line UPS system. However, there are different types of modular UPS systems available on the market, with varying degrees of reliability and availability. To represent the strengths and weaknesses of each architecture and accurately compare them to one another, a detailed...
According to the character of long-term repairable storage systems, a method for estimation and optimization of storage availability is presented. Such system experiences two storage periods, cold storage period and hot storage period. According to the different inspection methods of the two periods, we established the storage models based on periodic inspection and continuous inspection respectively,...
Safety Instrumented Systems (SIS) act as important safety barriers in industrial systems for preventing hazardous accidents. It is therefore significant to study the reliability issues of SIS. As a matter of fact, SIS have common behaviors such as periodic test policies to discover dangerous undetected failures. Modeling patterns capitalize the experience from modeling SIS. By reusing modeling patterns,...
Power transformer has an important role to transfer energy from power plant to consumer. There are 325 banks of power transformer had been installed in PLN TJBB which various ages and manufacturers. In order to manage the assets, PLN TJBB implemented asset management system based on ISO 55001. One of asset management objective is to fulfill transmission service quality level. However, transformer...
SF6 Gas-Insulated Metal-Enclosed Transmission Line (GIL) has the advantages of large transmitting capacity, low loss, small electromagnetic pollution for surroundings, strong capability to resist geological disasters, easy operation and maintenance, etc. In-depth research on the key technology of UHV GIL insulating part design, flexible line design, line manufacturing and detection, GIL installing...
DRAM is a crucial component in computing systems, and is expected to be even more important as data-intensive applications become more prominent. A key challenge in advancing DRAM technology is the growing cost of refresh operations, which can impose a large impact on the energy efficiency of DRAM modules. Existing refresh mitigation techniques all require hardware modifications, which may be undesirable...
In order to elevate equipment-oriented traditional asset management to system-oriented advanced asset management (AAM) decision-making for smart power grid, for the problem that influence of different positions of the equipment in network topology on system reliability is not taken into consideration in retiring strategies of transformer LCC (life cycle cost), which may cause overestimation or underestimation...
This paper proposes a mathematical maintenance model that analyses the effect of maintenance on the survival probability of medical equipment based on maintenance history and age of the equipment. The proposed model is simulated in Scilab using real data extracted from maintenance history of Anaesthesia Machine from Draeger. The analysis using survival approach reveals that conducting preventive maintenance...
Large-scale systems with arrays of solid state disks (SSDs) have become increasingly common in many computing segments. To make such systems resilient, we can adopt erasure coding such as Reed-Solomon (RS) code as an alternative to replication because erasure coding can offer a significantly lower storage cost than replication. To understand the impact of using erasure coding on system performance...
This article presents an analysis of the failures recorded data in railway substations from the Romanian Railway system. The data were recorded for 11 years, from 2006 until 2016, for two railway substations. Types of failure, causes of the defects, the protection which operated and other aspects are considered into the article.
Maximum-distance-separable (MDS) codes are a class of erasure codes that are widely adopted to enhance the reliability of distributed storage systems (DSS). In this paper, we develop a new approach to construction of simple (5, 3) MDS codes. With judiciously block-designed generator matrices, we show that the proposed MDS codes have a minimum stripe size α = 2 and can be constructed over a small (Galois)...
Reasonable maintenance strategy can decrease power grid operation costs and enhance competitiveness of power grid. Therefore, according to the principle of system condition-based maintenance, an equipment imperfect maintenance model is built based on a modified Kijima II model, which considers electrical equipments' maintenance outage model and repair outage model and the effects of equipment maintenance...
In order to improve the quality of life-cycle-cost of the transmission line system, this paper introduces the basic theory of the life-cycle-cost, analyse the construction of the lifecycle-cost of transmission line. Then two main parameters, the design life of transmission line and project fund discount rate, will be researched detailedly. At last, by giving the life-cycle-cost prediction model for...
Electrical equipment reliability model and maintaining equipment set choice are the fundamental of power system risk evaluation. Based on the online monitoring, electrical equipment reliability model is more and more detailed and accurate. However, the research about the maintaining equipment set choice is rough. At present, the decision about the maintaining equipment set choice is converted into...
Erasure codes are widely used in practical storage systems to prevent disk failure and data loss. However, these codes require excessive disk I/Os and network traffic for recovering unavailable data. As a result, the recovery performance of erasure codes is suboptimal. Among all erasure codes, Minimum Storage Regenerating (MSR) codes can achieve optimal repair bandwidth under the minimum storage during...
Erasure coding has been widely adopted to protect data storage against failures in production data centers. Given the hierarchical nature of data centers, characterizing the effects of erasure coding and redundancy placement on the reliability of erasure-coded data centers is critical yet largely unexplored. This paper presents a comprehensive simulation analysis of reliability on erasure-coded data...
Constant random and wear-out failures of sub-modules (SM) within a Modular Multi-level Converter (MMC) are examined. Constant random failures are calculated using the binomial distribution formula, using a constant failure rate. Wear-out failures are calculated using discrete Markov chain modelling and Monte Carlo estimation, with the failure rate of a SM increasing with time. The results are compared...
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