scholarly journals KARAKTERISTIK PETIR INDONESIA DAN PENGGUNAANNYA DALAM EVALUASI UNJUK KERJA SALURAN UDARA 150 KV SAAT TERJADI SAMBARAN PETIR

2021 ◽  
Vol 9 (1) ◽  
pp. 46-53
Author(s):  
Brian Bramantyo Satriaji Dwi Adiputro Harsono ◽  
Anindita Satria Surya ◽  
Kevin Gausultan Hadith Mangunkusumo ◽  
Andreas Putro Purnomoadi

Berdasarkan data historis, gangguan saluran transmisi udara di Indonesia mayoritas disebabkan oleh sambaran petir; hal tersebut mendorong PT PLN (Persero) sebagai perusahaan listrik milik negara untuk mengevaluasi unjuk kerja saluran udara terhadap sambaran petir. Pada makalah ini disajikan evaluasi karakterisasi petir menggunakan rekam data sistem deteksi petir/LDS (studi kasus untuk Jawa Barat) meliputi: jumlah sambaran, persentase polaritas, nilai modus arus puncak, persentase kejadian kumulatif, serta peta kerapatan petir. Evaluasi unjuk kerja saluran dilakukan melalui 1) simulasi tegangan lebih menggunakan perangkat lunak transient pada pemodelan saluran 150 kV untuk mengetahui korelasi arus puncak petir terhadap kenaikan tegangan pada insulator saat terjadi sambaran petir dan 2) evaluasi sudut lindung menggunakan Electro Geo-metric Model (EGM). Berdasarkan pengolahan data tahun 2018-2020, terdapat fluktuasi total kejadian petir per tahun dimana 84,63% (σ= 1,71) dari kejadian merupakan petir polaritas negatif. Modus nilai arus puncak petir adalah 12,33 kA (σ= 1,52), sementara persentase kejadian kumulatif memiliki knee point pada nilai 40 kA. Pola kerapatan petir tertinggi tidak mengalami perbedaan signifikan selama periode pengamatan dan bulan ke-7 merupakan periode dengan kejadian petir terendah. Hasil simulasi sambaran petir 40 kA pada kawat pembumiaan menunjukkan bahwa insulator mengalami kenaikan tegangan hingga 1083 kV; hal tersebut mendekati nilai Basic Impulse Insulation Level (BIL) dari insulator. Desain sudut lindung mampu mencegah shielding failure untuk arus petir ≥11 kA; meskipun demikian, perlu dicatat bahwa shielding failure akibat petir 10 kA menyebabkan kenaikan tegangan insulator melebihi nilai BIL. Peningkatan unjuk kerja saluran transmisi 150 kV tersebut dapat dilakukan dengan didasari oleh pertimbangan risk, cost dan benefit yang komprehensif.

10.31355/17 ◽  
2017 ◽  
Vol 1 ◽  
pp. 117-148
Author(s):  
Prafulla Kumar Padhi

NOTE: THIS ARTICLE WAS PUBLISHED WITH THE INFORMING SCIENCE INSTITUTE. Aim/Purpose.............................................................................................................................................................................................. Since the valuation of a born-global speculative start-up (BGSS) has been a guessing game and there is no framework in the literature from ethical fashion smart wearable (EFSW) venture valuation perspective, this research explores to create a holistic model using multi-stage valuation method to valuate BGSS at its inception and investigates how ethical is ethical fashion? Background................................................................................................................................................................................................ The concept of ‘Born-Global’ firm was introduced into business theory during 1988. Nowadays, ventures start with a global vision from their inception to introduce products and services in overseas markets. Speculative investment has been a common practice to start-up expedition. Investors gamble on speculative start-ups. The inception phase of any start-up is the embryonic phase and is, therefore, more speculative than successive phases for additional investments. BGSS at its inception possess no operating history. Today fashion industry is one of the largest industries globally, growing leaps and bounds with valuation at 3 trillion U.S. dollars. The emerging smart fashion wearable market projected to cross US$ 30 billion during 2017. Fashion exists not only in garments but also other wearable such as the bracelet, watches, jewelry, and other accessories. Ethical fashion is all about betterment for the people and community at large. This paper identifies the relevant actors and their impact on the ethical aspects and status of the fashion industry. Methodology............................................................................................................................................................................................... The methodology used in this research both qualitative and quantitative approach. Since ethical fashion is a social phenomenon, the qualitative approach is appropriate to deal with various perspective analysis of ethical fashion using case study on four ethical fashion smart wearable ventures. The quantitative method calibrates the valuation of a BGSS at the inception stage using a noble pragmatic multi-stage valuation method because it provides the incentive to focus on achieving the best risk/cost ratio. Contribution.............................................................................................................................................................................................. This research bestows valuable insight using a noble multi-stage valuation method that has been proven successful based on author´s extensive practice to value BGSS at its inception contributing new knowledge to the literature. The application of informing system to frame the discussion on the inter-disciplinary domain of ethical fashion smart wearable creates awareness for fashion industry stakeholders and academic researchers. Findings.................................................................................................................................................................................................... The analysis shows that BGSS is a contemporary phenomenon since so many smart fashions wearable companies have gone through thought provoking and compelling stories to became successful in a highly competitive smart fashion wearable industry. BGSS concept is a brand-new perspective in the EFSW academic research. The findings of this research provide information to various stakeholders of the fashion industry and benefit to a global community at large with a more nuanced understanding of the changes and challenges of the emerging EFSW industry and the way to measure the valuation of a venture at its inception. Recommendations for Practitioners......................................................................................................................................................... This paper reveals nuance understanding for the practitioners in the BGSS valuation at its inception. Since all the traditional valuation methods have their drawbacks when applied to the inception stage of BGSS, this study recommends using multi-stage valuation method because it provides incentive for the best risk/cost ratio. Fashion brands (designers and other stakeholders) should abide by the ethical criteria to make a difference in the global community at large by reducing degradation of the environmental conditions. For the future of ethical fashion, ethical choices must be an available alternative to customers. Fashion companies need to embark upon design to not only be ethical but also stylish, therefore need to create trust by adopting transparency and integrity throughout the value chain. Fashion brand should take advantage of ethical fashion criteria to provide assurance to consumers with socio-cultural aspects in mind, to promote their fashion collections effectively. Recommendation for Researchers............................................................................................................................................................... More research work needs to be accomplished to have a clear analysis of the ethical fashion perspective to cover environmental, socio-cultural, fair trade, human rights, animal rights and other aspects. It is important to study the various stages of BGSS valuation from growth stage to initial public offering stage and beyond to bridge the gap between academic research and practitioners using the multi-stage valuation method. Impact on Society.......................................................................................................................................................................................... Since ethical fashion is of great significance for the contemporary society, raising awareness among various cultural communities globally to promote avantgarde ways regarding ethical fashion criteria, specifically to curb the degradation of the environment, stopping the cruelty on animals and protecting the human rights among consumers is paramount. Future Research............................................................................................................................................................................................ This study will bridge the gap between practice and academic research, scholars should embark upon creating a total addressable market (TAM) theory and empirical analysis studies because the total addressable market is the key and practical determinant of BGSS success. Ethical fashion academic research should be pursued beyond sustainability on smart wearable.


2020 ◽  
Vol 18 ◽  
Author(s):  
Zlatko Fras ◽  
Dimitri P. Mikhailidis

: In this second part of a review of the IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT), we discuss the findings in relation to patients with stroke, the ACS phenotype, history of coronary artery bypass graft surgery, heart failure, concurrent polyvascular atherosclerotic cardiovascular disease (ASCVD) and diabetes mellitus, and different levels of expression of selected cardiovascular biomarkers. The combination therapy was proven safe, and drug discontinuation rates were not increased by adding ezetimibe. Since both statins and ezetimibe are now almost globally generically available, we can conclude that for secondary prevention of ASCVD, adding ezetimibe to high-intensity statin therapy further reduces low-density lipoprotein cholesterol (LDL-C) and cardiovascular risk cost-effectively.


Machines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 124
Author(s):  
Dantam Rao ◽  
Madhan Bagianathan

Currently, permanent-magnet-type traction motors drive most electric vehicles. However, the potential demagnetization of magnets in these motors limits the performance of an electric vehicle. It is well known that during severe duty, the magnets are demagnetized if they operate beyond a ‘knee point’ in the B(H) curve. We show herein that the classic knee point definition can degrade a magnet by up to 4 grades. To prevent consequent excessive loss in performance, this paper defines the knee point k as the point of intersection of the B(H) curve and a parallel line that limits the reduction in its residual flux density to 1%. We show that operating above such a knee point will not be demagnetizing the magnets. It will also prevent a magnet from degenerating to a lower grade. The flux density at such a knee point, termed demag flux density, characterizes the onset of demagnetization. It rightly reflects the value of a magnet, so can be used as a basis to price the magnets. Including such knee points in the purchase specifications also helps avoid the penalty of getting the performance of a low-grade magnet out of a high-grade magnet. It also facilitates an accurate demagnetization analysis of traction motors in the worst-case conditions.


1980 ◽  
Vol 87 (7) ◽  
pp. 567
Author(s):  
George D. Parker

1987 ◽  
Vol 27 (7) ◽  
pp. 824
Author(s):  
Matthew Indeck ◽  
Sheryl Peterson ◽  
Joseph Smith ◽  
Sheldon Brotman

Author(s):  
Guy Decorges ◽  
Chad Quaglia ◽  
Theodore Zoli ◽  
Syed Abbas ◽  
Jacob Mandell

<p>The original 100 m long Myrtle Avenue Viaduct was constructed in 1913 and carried two critical New York City Transit (NYCT) subway tracks in Brooklyn. The geometric configuration of the viaduct weaves through a narrow corridor on a NYCT-owned private right-of-way with multiple adjacent properties, including occupied houses straddling the viaduct on both the east and west sides. Many of these residents and businesses had to be relocated during the 10-month replacement process. Constant operation and exposure to the elements resulted in severe deterioration of the original viaduct leaving it in a state of disrepair. Factoring risk, cost and existing conditions of the structure, the engineer’s assessment led to a proposed design alternative beyond the client’s expectations, which originally called for replacement of the superstructure only. The designer recommended an entirely new structure and promised completion within the same time frame as the originally planned partial replacement.</p>


Sign in / Sign up

Export Citation Format

Share Document