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This paper proposes automatic power changeover switch system applied superconducting fault current limiter (SFCL) of the Korea electric railway using 25 kV-AC Scott transformer. The electric railway needs neutral section to separate two different electrical power phase to m phase and t phase. While the train passes through the neutral section, the electrical power supply phase is changed over to other phase. And that time, the train must turn off the circuit breaker to avoid transient as ‘inrush-current’ and ‘arc’. These cause negative problems as speed decline of the train, a shorter life of the train circuit breaker. To improve the problems, the inrush current limitation method is proposed. In addition, we analysed the effect of proposed method using time-domain transient simulation software (PSCAD/ EMTDC). [ABSTRACT FROM PUBLISHER]

In Korea, the superconducting power cable has been developed since 2001, with the basic specifications of 22.9 kV/50 MVA. The superconducting power cable can carry more than 2 to 5 times higher electric power compared with conventional ones. It is important to test the DC critical current related with its power capacity before applying to the real power grid. In 1995, several international standards organizations including IEC, decided to unify the use of statistical terms related with "accuracy" or "precision" in their standards. It was decided to use the word "uncertainty" for all quantitative (associated with a number) statistical expressions. In this paper, we measured DC critical current of 22.9 kV/50 MVA superconducting power cable with several voltage tap and analyzed the uncertainty with these results. These analyzed results can be applied the standardization of the superconducting power cable [ABSTRACT FROM AUTHOR]

Offshore wind farm (WF) projects have been promoted by support schemes as part of the expansion of renewable energy resources in Korea. This paper examines in detail how the Renewable Portfolio Standard (RPS), which was adopted post the Feed-in-Tariff scheme in 2012, has had a profound impact on the economic benefits of offshore WFs in Korea. A framework for analyzing the economic viability of RPS is presented and applied to the sixth basic plan for long-term electricity supply and demand in Korea. The electricity market price is forecast using a reformulated probabilistic production cost (PPC) model, and the renewable energy certificate (REC) price is calculated using its determination rule. The results show that the existing RPS will be ineffective in increasing the penetration of offshore WFs in Korea; however, they also indicate that the economic viability of offshore WFs could be improved by adjusting the existing RPS. [ABSTRACT FROM AUTHOR]

Abstract: A large AC generator is an important component of the power system. Researches on the AC generator relaying for the next-generation ECMS and an efficient operation of protection control system are necessary. These require developments on detailed generator modeling and internal fault analysis, and prototyping for multifunctional IED device dedicated to next-generation production. In this paper, over-excitation relaying algorithm is one of the main protection elements which have an important role in DGPS(Digital Generator Protection System), was proposed. This paper first briefly introduces a principles of over-excitation and DFT-based gain compensation algorithm was adopted for the frequency measurement. Subsequently, protection scheme of over-excitation was presented. The 765[kV] modeling data of South Korea using EMTP-RV was used for simulations. The simulation result of over-excitation relaying are also provided. [Copyright &y& Elsevier]

Power grids deal with the business of generation, transmission, and distribution of electric power. Recently, interest in power quality in electrical distribution systems has increased rapidly. In Korea, the communication network to deliver voltage, current, and temperature measurements gathered from pole transformers to remote monitoring centers employs cellular mobile technology. Due to high cost of the cellular mobile technology, power quality monitoring measurements are limited and data gathering intervals are large. This causes difficulties in providing the power quality monitoring service. To alleviate the problems, in this paper we present a communication infrastructure to provide low cost, reliable data delivery. The communication infrastructure consists of wired connections between substations and monitoring centers, and wireless connections between pole transformers and substations. For the wireless connection, we employ a wireless sensor network and design its corresponding data forwarding protocol to improve the quality of data delivery. For the design, we adopt a tree-based data forwarding protocol in order to customize the distribution pattern of the power quality information. We verify the performance of the proposed data forwarding protocol quantitatively using the NS-2 network simulator. [ABSTRACT FROM AUTHOR]