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남시복(S. B. Nam),이훈구(H. G. Lee) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.5
Frequency is an important operating parameter of a power system. Electric power systems sustain transient frequency swings whenever the balance between generation and load does not no longer hold. To cope with this Constraints, it requires an accurate and high speedy frequency deviation estimation technique and suitable adjustment to obtain the power system energy balance. This paper describes the design, computational aspects and implementation of an iterative technique for measuring power system. The rate change of the phase angle is used for estimation. To confirm the validity of the proposed algorithm, the simulation studies carried out on a typical 154[KV] double TIL system by using EMTP software. Some test results are presented in the paper.
남시복(S. B. Nam),이훈구(H. G. Lee),마석범(S. B. Ma),김진수(J. S. Kim) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.10
Frequency and phasor are the most important quantities in power system operation because they can reflect the whole power system situation. Frequency reflects the dynamic energy balance between load and generating power, while operators use phasor to constitute the state of system and, moreover, phasor based line relays are currently used in most power systems. So frequency and phasor are regarded as indices for the operating power systems in practice. The proposed technique is suitable for estimation near-nominal, nominal, and off-nominal frequencies. It is useful in designing microprocessor- based relays and meters that need to measure power system frequency. Performance test results, using signals from EMTP source and Excel program, indicate that the proposed technique can provide accurate estimates within 16ms. Maximum estimation errors observed during testing are of the order of 0.006㎐ for nominal, near-nominal, and off-nominal frequencies. The proposed technique provides accurate estimates in presence of noise and harmonics and in case ground fault. The rate change of the phase angle is used for estimation. To confirm the validity of the proposed algorithm, the simulation studies carried out on a typical 154[KV] double T/L system by using EMTP software. Some test results are presented in the paper.
김진수(J. S. Kim),이훈구(H. G. Lee),남시복(S. B. Nam),마석범(S. B. Ma) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.10
We use electric drill for cutting wood. In electric drills, there is the core-drill that bores concrete-wall. The core-drill is used in construction or remodeling areas. Therefore we require safety in working with the core-drill. In this paper, new controller of core-drill for concrete-wall is proposed. Experimental results show the validity of the proposed controller.