• Journal of Electrical Engineering and Technology
• /
• v.12 no.5
• /
• pp.1719-1728
• /
• 2017

Recent concerns about environmental conditions have triggered the growing interest in using green energy resources. These sources of energy, however, bring new challenges mainly due to their uncertainty and intermittency. In order to alleviate the concerns on the penetration of intermittent energy resources, this paper investigates impacts of realizing demand-side potentials. Among different demand-side management programs, this paper considers demand response wherein consumers change their consumption pattern in response to changing prices. The research studies demand response potentials from different load sectors on generation system well-being. Consumers' sensitivity to time-varying prices is captured via self and cross elasticity coefficients. In the calculation of well-being indices, sequential Monte Carlo simulation approach is accompanied with fuzzy logic. Finally, IEEE-RTS is used as the test bed to conduct several simulations and the associated results are thoroughly discussed.

• Journal of Power Electronics
• /
• v.16 no.4
• /
• pp.1612-1620
• /
• 2016

This paper presents the dynamic excitation control of a siphon-turbine coupled pico-hydro powered cage rotor induction generator and load matching for off-grid electricity generation. Through the proposed dual-role of the current-controlled voltage source converter (VSC), acting as static synchronous compensator and load controller, real and reactive power are dynamically controlled in a decoupled manner with a self supported DC-bus. The proposed scheme entails minimal computation for ensuring the rated (set) capacity of real power. The scheme also exhibits fault immunity for protection, thus enabling the effective handling of constant power electrical loads presented by base telecom station towers in remote locations. The performance of the system is evaluated under MATLAB/Simulink and is experimented through a developed hardware prototype. Simulation and experimental results show close conformity and validate the effectiveness of the proposed scheme.

• Convergence Security Journal
• /
• v.22 no.1
• /
• pp.149-158
• /
• 2022

R.o.K Marine Corps was established on April 15, 1949 at Deoksan Air Base in Jinhae. When they fought in the Korean War and the Vietnam War, they were sure to win, so they were loved and trusted by the people. Strong combat power is only possible when an advanced barracks culture is established. Today's new generation of soldiers have strong characteristics ; self-centered and individualistic. R.o.K Marine Corps officers must understand the characteristics of the new generation of soldiers and strive to develop creative leadership in order to make them utilize their characteristics. In addition, as cutting-edge science and technology develops along with the 4th industrial revolution, R.o.K Marine Corps officers should work hard to acquire professional tactical knowledge and self-development. Therefore, Marine Corps officers should do their best to understand the characteristics of the new generation of soldiers and demonstrate leadership to become a strong force trusted by the people.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.2
• /
• pp.257-268
• /
• 2014

In this study, flow-driven rotor simulations with a given load are conducted to analyze the operational characteristics of a vertical-axis Darrieus turbine, specifically its self-starting capability and fluctuations in its torque as well as the RPM. These characteristics are typically observed in experiments, though they cannot be acquired in simulations with a given tip speed ratio (TSR). First, it is shown that a flow-driven rotor simulation with a two-dimensional (2D) turbine model obtains power coefficients with curves similar to those obtained in a simulation with a given TSR. 3D flow-driven rotor simulations with an optimal geometry then show that a helical-bladed turbine has the following prominent advantages over a straight-bladed turbine of the same size: an improvement of its self-starting capabilities and reduced fluctuations in its torque and RPM curves as well as an increase in its power coefficient from 33% to 42%. Therefore, it is clear that a flow-driven rotor simulation provides more information for the design of a Darrieus turbine than a simulation with a given TSR before experiments.

• Proceedings of the KIEE Conference
• /
• 2005.10c
• /
• pp.26-28
• /
• 2005

Induction generator is the most common generator in wind energy systems because of its simplicity, ruggedness, little maintenance, price and etc. But the main drawbacks in induction generator is its need of reactive power means to build up the terminal voltage. This drawback is not an obstacle today where PWM inverters can accurately supplies the induction generator with its need from reactive power. For a insurance of three-phase induction generator requires capacitive reactance of the terminal. Most of previous work uses numerical iterative method to determine this minimum capacitor. But the numerical iteration takes long time and divergence may be occurs. In this paper is presented the design methods of the minimum self-excited capacitor required for induction generator operation. And a new formula from the equivalent circuit for stable generation operation of self-excited induction generator calculates the proper capacity to obtain the terminal voltage of the load stage. The validity of proposed design methods is confirmed by experimental and computed results.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.938-940
• /
• 2004

With increased emphasis on non-conventional energy system and autonomous power generation, development of improved and appropriate generating system has assumed signification. This paper describes the performance analysis of 2-phase self-excited induction generators. The minimum capacitance of self-excited capacitor connected auxiliary winding is determined the suitable value using circuit equations of auxiliary winding. For the steady state analysis, the equivalent circuit of 2-phase induction generators is used as circuit modeling using the double-revolving field theory. The validity of designed generator system will be confirmed by experimental and computed results.

• Nuclear Engineering and Technology
• /
• v.49 no.5
• /
• pp.896-904
• /
• 2017

Several Generation IV nuclear reactor concepts have goals for optimizing investment recovery through phased introduction of multiple units on a common site with shared facilities and/or reconfigurable energy conversion systems. Additionally, small modular reactors are suitable for remote deployment to support highly localized microgrids in isolated, underdeveloped regions. The long-term economic viability of these advanced reactor plants depends on significant reductions in plant operations and maintenance costs. To accomplish these goals, intelligent control and diagnostic capabilities are needed to provide nearly autonomous operations with anticipatory maintenance. A nearly autonomous control system should enable automatic operation of a nuclear power plant while adapting to equipment faults and other upsets. It needs to have many intelligent capabilities, such as diagnosis, simulation, analysis, planning, reconfigurability, self-validation, and decision. These capabilities have been the subject of research for many years, but an autonomous control system for nuclear power generation remains as-yet an unrealized goal. This article describes a functional framework for intelligent, autonomous control that can facilitate the integration of control, diagnostic, and decision-making capabilities to satisfy the operational and performance goals of power plants based on multimodular advanced reactors.

• Journal of Power Electronics
• /
• v.16 no.4
• /
• pp.1513-1525
• /
• 2016

Rapid and accurate phase synchronization is critical for the reliable control of grid-tied inverters. However, the commonly used software phase-locked loop methods do not always satisfy the need for high-speed and accurate phase synchronization under severe grid imbalance conditions. To address this problem, this study develops a novel open-loop phase locking scheme based on a synchronous reference frame. The proposed scheme is characterized by remarkable response speed, high accuracy, and easy implementation. It comprises three functional cascaded blocks: fast orthogonal signal generation block, fast fundamental-frequency positive sequence component construction block, and fast phase calculation block. The developed virtual orthogonal signal generation method in the first block, which is characterized by noise immunity and high accuracy, can effectively avoid approximation errors and noise amplification in a wide range of sampling frequencies. In the second block, which is the foundation for achieving fast phase synchronization within 3 ms, the fundamental-frequency positive sequence components of unsymmetrical grid voltages can be achieved with the developed orthogonal signal construction strategy and the symmetrical component method. The real-time grid phase can be consequently obtained in the third block, which is free from self-tuning closed-loop control and thus improves the dynamic performance of the proposed scheme. The proposed scheme is adaptive to severe unsymmetrical grid voltages with sudden changes in magnitude, phase, and/or frequency. Moreover, this scheme is able to eliminate phase errors induced by harmonics and random noise. The validity and utility of the proposed scheme are verified by the experimental results.

• Archives of design research
• /
• v.15 no.1
• /
• pp.213-224
• /
• 2002

We've already living our lives in the 21s1 century. This century, even alone, means enormous changes and innovations. Namely, we have been encountering various forms of generation changes such as digital generation, globalization generation, consumer generation, and brand power generation. Among these, there have been extraordinary changes in consumers and the environment of consumer market, and it is noteworthy of paying attention to the transition of the leader of the consumer market from producers to consumers. Such changes will affect not only all fields related to market environment but also entire fields including future products and sales. Hereupon, it is intended to foresee and analyze the trend in the consumer market of the 21st century and investigate changes in the consumer market and the environment of consumers. Also, the world has brought a single space of economy along with globalization and the era of self-imposed competition, and multi-national enterprises have emerged and, at the same time, their brands can be seen around the world. Hence, they have been trying to maintain their own power brands for the century. In the past, brand meant the name of a product in general. But, in the present, it has another meaning such that the brand itself provides psychological satisfaction and trustworthiness. Hereupon, this study intends to foresee changes in the trend of the consumer market of the 21s1 century, to ,outlook the trend of the consumer market along with study of power brand strategies, and to pursue creative strategies for power brand.

• Journal of the Korean Solar Energy Society
• /
• v.39 no.6
• /
• pp.137-151
• /
• 2019

This study estimated the available renewable market potential based on Levelized Cost Of Electricity and then assessed the renewable derived energy self-sufficiency for the unit of local government in South Korea. To calculate energy self-sufficiency, 1 km gridded market renewable generation and local government scale of final energy consumption data were used based on the market costs and statistics for the recent three years. The results showed that the estimated renewable market potentials were 689 TWh (Install capacity 829 GW, 128 Mtoe), which can cover 120% of power consumption. 55% of municipalities can fully replace the existing energy consumption with renewable energy generation and the surplus generation can compensate for the rest area through electricity trade. However, it was confirmed that, currently, 47% of the local governments do not fully consider all renewable energy sources such as wind, hydro and geothermal in establishing 100% renewable energy. The results of this study suggest that energy planning is decentralized, and this will greatly contribute to the establishment of power planning of local governments and close the information gap between the central government, the local governments, and the public.