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Seoul, South Korea

Nam S.-R.,Myongji University | Kang S.-H.,Myongji University | Lee J.-H.,Korea Power Exchange | Ahn S.-J.,Chonnam National University | Choi J.-H.,Chonnam National University
Energies | Year: 2013

In this paper we propose a new method to evaluate the effects of nationwide conservation voltage reduction (CVR) on peak-load shaving, using substation operating results management system (SOMAS) data. Its evaluation is based on a national CVR factor, which is defined as the weighted average of CVR factors associated with all transformer banks and weighting coefficients are determined by the reconstructed loads corresponding to each transformer bank. To make use of the data resulting from nationwide CVR without installing additional measuring devices, we adopt a linearized static-load model with a linearizing parameter. SOMAS data are used to evaluate the effects of nationwide CVR on peak-load shaving in the Korean power system. Evaluation results show that the national CVR factor of the Korean power system has small values in the summer season and large values in the winter season. This means that the effect of nationwide CVR on peak-load shaving in the Korean power system presents stronger benefits during winter months. © 2013 by the authors; licensee MDPI, Basel, Switzerland. Source

Chung K.-H.,Korea Electrotechnology Research Institute | Park M.-G.,Korea Power Exchange | Hur D.,Kwangwoon University
Transactions of the Korean Institute of Electrical Engineers | Year: 2015

The virtual power plant (VPP) is a new technology to achieve flexibility as well as controllability, like traditional centralized power plants, by integrating and operating different types of distributed energy resources (DER) with the information communication technology (ICT). Though small-sized DERs may not be controlled in a centralized manner, these are more likely to be utilized as power plants for centralized dispatch and participate in the energy trade given that these are integrated into a unified generation profile and certain technical properties such as dispatch schedules, ramp rates, voltage control, and reserves are explicitly implemented. Unfortunately, the VPP has been in a conceptual stage thus far and its common definition has not yet been established. Such a lack of obvious guidelines for VPP may lead to a further challenge of coming up with the business model and reinforcing the investment and technical support for VPP. In this context, this paper would aim to identify the definition of VPP as a critical factor in smart grid and, at the same time, discuss the details required for VPP to actively take part in the electricity market under the smart grid paradigm. Copyright © The Korean Institute of Electrical Engineers. Source

Kong S.,Korea University | Kim Y.,Korea University | Joo S.-K.,Korea University | Kim J.H.,Korea Power Exchange
Digest of Technical Papers - IEEE International Conference on Consumer Electronics | Year: 2014

This paper presents Cepstrum smoothing-based feature extraction method to reduce the variation of the characteristic signals of home appliance for Nonintrusive Load Monitoring (NILM). In this paper, a data acquisition system is also developed to obtain only characteristic signals of appliances and to filter the noise inputted from the power supply. Testing results are provided to demonstrate the effectiveness of the proposed method. © 2014 IEEE. Source

Kang S.-G.,Korea University | Seo S.,Korea University | Lee B.,Korea University | Joo J.-Y.,Korea Power Exchange
Journal of Electrical Engineering and Technology | Year: 2010

This paper presents a new algorithm for determining generator operation point for maintaining stability considering generator faults in Jeju-Haenam HVDC system. As the HVDC system consumes reactive power for the transmission of active power substantially, compensation of reactive power is essential. And the HVDC system is operated on frequency control mode. That is to say, the HVDC system almost manages system frequency. Therefore, we recognized that the Jeju system could be unstable if the reactive power consumed by the HVDC is insufficient when out-of-step occurs with large generators. When the solution of power flow analysis does not converge due to the unstable system phenomenon, we have difficulty in establishing countermeasures as the post-fault information is not available. In this paper, for the purpose of overcoming this difficulty in establishing countermeasures, we introduce the CPF(Continuation Power Flow) algorithm. This paper suggests an algorithm for calculating the output limitation of the generator to maintain the stability in case of generator fault in the Jeju system. Source

Nam S.-R.,Myongji University | Kang S.-H.,Myongji University | Lee J.-H.,Korea Power Exchange | Choi E.-J.,Korea Power Exchange | And 2 more authors.
Energies | Year: 2013

This paper proposes a linearized load model to evaluate the effect of conservation voltage reduction at a national level. In this model, the respective active and reactive linearizing parameters for active and reactive loads in a power system are estimated using energy management system (EMS) data resulting from conservation voltage reductions. To verify the validity of the linearized load model, PSS/E simulations were conducted for a test power system. Given that conservation voltage reductions are usually executed in the range of 2.0%-5.0%, the proposed model was found to be sufficient to accurately evaluate the effect of conservation voltage reduction. Additionally, Korean EMS data were used to estimate the linearizing parameters for aggregated loads in an actual power system. © 2013 by the authors. Source

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