• Journal of Industrial Technology
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• v.32 no.A
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• pp.9-13
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• 2012

In this paper, we investigate maximum transmission capacity of wireless ad-hoc networks. In the investigation, we consider a network topology with regularly located nodes. For the topology, we investigate the maximum transmission capacity with RTS/CTS medium access protocol, and next, we study the maximum transmission capacity without the protocol. We see that the results of our study overall follows the result of Gupta and Kumar's research.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.464-477
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• 2019

With the sustained and rapid development of new energy sources, the demand for electric energy is increasing day by day. However, China's energy distribution is not balanced, and the construction of transmission lines is in a serious lag behind the improvement of generating capacity. So there is an urgent need to increase the utilization of transmission capacity. The transmission capacity is mainly limited by the maximum allowable operating temperature of conductor. At present, the evaluation of transmission capacity mostly adopts the static thermal rating (STR) method under severe environment. Dynamic thermal rating (DTR) technique can improve the utilization of transmission capacity to a certain extent. In this paper, the meteorological parameters affecting the conductor temperature are analyzed with the IEEE standard thermal equivalent equation of overhead transmission lines, and the real load capacity of 220 kV transmission line is calculated with 7-year actual meteorological data in Weihai. Finally, the thermal load capacity of DTR relative to STR under given confidence is analyzed. By identifying the key parameters that affect the thermal rating and analyzing the relevant environmental parameters that affect the conductor temperature, this paper provides a theoretical basis for the wind power grid integration and grid intelligence. The results show that the thermal load potential of transmission lines can be effectively excavated by DTR, which provides a theoretical basis for improving the absorptive capacity of power grid.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.213-215
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• 1999

This paper presents a transmission cost allocation through application of a new reliability index in transmission pricing in competitive electric industry. The proposed method allocates a fair use of transmission system charge given separately to individual generator by capacity usage, based on the contribution of individual generator considering N-1 contingency in reliability margin of transmission capacity, and offers more alternatives of pricing in using transmission capacity and transmission margin.

• Journal of Communications and Networks
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• v.10 no.2
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• pp.163-174
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• 2008

Performance of downlink transmission strategies exploiting cooperative transmit diversity is investigated for distributed multiple-input single-output (MISO) systems, for which geographically distributed remote antennas (RA) in a cell can either communicate with distinct mobile stations (MS) or cooperate for a common MS. Statistical characteristics in terms of the signal-to-interference-plus-noise ratio (SINR) and the achievable capacity are analyzed for both cooperative and non-cooperative transmission schemes, and the preferred mode of operation for given channel conditions is presented using the analysis result. In particular, we determine an exact amount of the maximum achievable gain in capacity when RAs for signal transmission are selected based on the instantaneous channel condition, by deriving a general expression for the SINR of such antenna selection based transmission. For important special cases of selecting a single RA for non-cooperative transmission and selecting two RAs for cooperative transmission among three RAs surrounding the MS, closed-form formulas are presented for the SINR and capacity distributions.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.37-40
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• 1999

In this paper, we analyzed transmission capability of VDSL system under the various noise in VDSL transmission lines. For this, we calculated transmission capacity using loading algorithm with transmission channel which suggested by ANSI DSL standard group TIE1.4. As a result, we've got approximated outcome similiar with target capacity in VDSL systems in short range. But we couldn't have got a outcome with target capacity in long range.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.129-133
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• 1999

In recent years, there is a growing needs for large capacity underground power transmission lines with the increasing demand of electric power in the urban area, where various environmental limitations are imposed on the overhead transmission lines. But it is difficult to get the space for the underground power transmission cables because of complicated distributions of underground public facilties such as subway, water pipes, gas etc. As the superconducting power cables have the large power transmission capacity, the high power transmission capacity, the high power transmission density, and low loss characteristics in comparison with a conventional cable, it would be a solution to meet the increased power demand. In this paper, the results of the conceptual design and analysis of power system of HTS power transmission cable is described.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.6
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• pp.350-357
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• 2004

In a deregulated electricity generation market, the sufficient capacity of transmission lines will promote the competition among generation companies (Gencos). In this paper, we show that Gencos' possession of rights to collect congestion rents may increase the competition effects of the transmission lines. In order for concrete analysis on this effect, a simple symmetric market model is introduced. In this framework, introducing the transmission right to the Gencos has the same strategic effects as increasing the line capacity of the transmission line. Moreover, the amount of effectively increased line capacity is equal to the amount of the line rights. We also show that the asymmetric share of the financial transmission rights may result in an asymmetric equilibrium even for symmetric firms and markets. We also demonstrate these aspects in equal line rights model and single firm line rights model. Finally, a numerical example is provided to show the basic idea of the proposed paper.

• Structural Engineering and Mechanics
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• v.71 no.3
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• pp.305-315
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• 2019

Extremely long-span transmission tower-line system is an indispensable portion of an electricity transmission system, and its failures or collapse can impact on the entire electricity grid, affect the modern life, and cause great economic losses. It is therefore imperative to investigate the failure and safety of the transmission tower subjected to ground motions. In the present study, a detailed finite element (FE) model of a representative extremely long-span transmission tower-line system is established. A segmental damage indicator (SDI) is proposed to quantitatively assess the damage level of each segment of the transmission tower under earthquakes. Additionally, parametric studies are conducted to investigate the influence of different ground motions and incident angles on the ultimate capacity and weakest segment of the transmission tower. Finally, the collapse fragility curve in terms of the maximum SDI value and PGA is plotted for the exampled transmission tower. The results show that the proposed SDI can quantitatively assess the damage level of the segments, and thus determine the ultimate capacity and weakest segment of the transmission tower. Moreover, the different ground motions and incident angles have a significant influence on the SDI values of the transmission tower, and the collapse fragility curve is utilized to evaluate the collapse resistant capacity of the transmission tower subjected to ground motions.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.11-17
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• 2012

Capacity is a traditional issue in wireless network and is closely related to the service quality of network providers, therefore it is a main interest of them. Especially, when a big match of sport game or a special event are held in a place and a large crowd temporarily gathers, a need of big transmission capacity greater than usual usage in the area is required, where network providers need a scheme to temporarily expand network capacity in any specified area. This paper focuses on temporary expansion of wireless network capacity for such situations. In this paper, we first investigate maximum transmission capacity of wireless ad-hoc networks. In the investigation, we consider a network topology with regularly located nodes. For the topology, we investigate the maximum transmission capacity with RTS/CTS medium access protocol, and then we study the maximum transmission capacity without the protocol. Next, we propose a scheme to expand network capacity and analyze the performance of the proposed scheme. From the results of analysis, we see that our proposed scheme is effective for temporary expansion of wireless network capacity.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.9
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• pp.424-430
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• 2001

A multi-level optimal power flow(OPF) algorithm has been evolved from a simple two stage optimal Power flow algorithm for constrained power economic dispatch control. In the proposed algorithm, we consider various constraints such as ower balance, generation capacity, transmission line capacity, transmission losses, security equality, and security inequality constraints. The proposed algorithm consists of four stages. At the first stage, we solve the aggregated problem that is the crude classical economic dispatch problem without considering transmission losses. An initial solution is obtained by the aggregation concept in which the solution satisfies the power balance equations and generation capacity constraints. Then, after load flow analysis, the transmission losses of an initial generation setting are matched by the slack bus generator that produces power with the cheapest cost. At the second stage we consider transmission losses. Formulation of the second stage becomes classical economic dispatch problem involving the transmission losses, which are distributed to all generators. Once a feasible solution is obtained from the second stage, transmission capacity and other violations are checked and corrected locally and quickly at the third stage. The fourth stage fine tunes the solution of the third stage to reach a real minimum. The proposed approach speeds up the two stage optimization method to an average gain of 2.99 for IEEE 30, 57, and 118 bus systems and EPRI Scenario systems A through D testings.