modification, be used to perform local cross spectral analysis with very good time resolution. The 'phase correction' absolutely references the phase of the ...
Power System Relaying Power Quality Analysis Using S-Transform Dash, PEK.; Panigrahi, B.K.; Panda, G. Author Affiliation: Multimedia University, Malaysia; U.C.E., Burla, India; Regional Engineering College, Rourkela, India
Abstract: This paper presents a new approach for power quality analysis using a modified wavelet transform known as S-transform. The local spectral information of the wavelet transform can, with slight modification, be used to perform local cross spectral analysis with very good time resolution. The 'phase correction' absolutely references the phase of the wavelet transform to the zero time point, thus assuring that the amplitude peaks are regions of stationary phase. The excellent time-frequency resolution characteristic of the S-transform makes it an attractive candidate for analysis of power system disturbance signals. Several power quality problems are analysed using both the S-transform and discrete wavelet transform, showing clearly the advantage of the S-transform in detecting, localizing and classifying the power quality problems. Keywords: S-transform, wavelet transform, power quality problems, phase correction. Preprint Order Number: PE-505PRD (04-2002) Discussion Deadline: September 2002
from the inrush current if the improved waveform correlation coefficient between the first half-cycle and the latter-half-cycle of the above measurand is over a threshold. Test results show that all types of internal faults, even those accompanied by the magnetizing inrush, can be correctly identified from the inrush with the proposed algorithm. Besides high security, this scheme has satisfactory sensitivity. Also, this algorithm can be easily implemented in the real-time process. Keywords: Improved waveform correlation algorithm, intemal fault, inrush, transformer differential protection. Preprint Order Number: PE-1 12PRD (04-2002) Discussion Deadline: September 2002
A Current-Based Solution for Transformer Differential Protection Part II: Relay Description and Evaluation Guzman, A.; Zocholl, S.; Benmouyal, G.; Altuve, Hj. Author Affiliation: Schweitzer Engineering Laboratories, Inc., Pullman, WA; Universidad Autonomade Nuevo Leon Abstract: This paper describes a new approach for transformer differential protection that ensures security for extemal faults, inrush, and overexcitation conditions and provides dependability for internal faults. This approach combines harmonic restraint and blocking methods with a wave shape recognition technique. We compare in the paper the behavior of some traditional transformer protection methods to that of the new method for real cases of magnetizing inrush conditions. Keywords: Protective relaying, power transformer protection, differential protection. Preprint Order Number: PE-086PRD (04-2002) Discussion Deadline: September 2002
A Novel Approach Using a Firann for Fault Detection and Direction Estimation for High Voltage Transmission Lines Orille-Fernandez, A.L.; Ghonaim, N.K.I. Author Affiliation: Polytechnic University of Catalonia, Barce- A New Protection Scheme for Fault Detection, Direction Discrimination, lona, Spain Abstract: This paper presents a novel approach to fault detection, Classifi'cation, and Location in Transmission Lines faulted phase selection and direction estimation based on Artificial Neural Networks (ANN). The suggested approach uses the Finite Im- Jiang, J.A.; Chen, C.S.; Liu, C.W pulse Response Artificial Neural Network (FIRANN) with the same Author Affiliation: National Taiwan University, Taipei, Taiwan structure and parameters in each relaying location. Our main objective Abstract: This paper presents a new adaptive fault protection in this work is to find a fast relay design with a detection time not de- scheme for transmission lines using synchronized phasor measurependent on fault conditions (i.e. current transformer saturation, dy- ments. The work includes fault detection, direction discrimination, namic arcing faults, short circuit level and system topology) and that classification and location. Both fault detection and fault location indiuses only unfiltered voltage and current samples at 2 kHz. The sug- ces are derived by using two-terminal synchronized measurements ingested relay, which we have named FIRANN-DSDST, is composed of corporated with distributed line model and modal transformation a FIRANN together with post processing elements. The FIRANN is theory. The fault detection index is composed of two complex phasors trained globally using training pattems from more than one relaying and the angle difference between the two phasors determines whether position in order to be as general as possible. The FIRANN is trained the fault is intemal or external to the protected zone. The fault types can using an improved training algorithm, which depends on a new synap- be classified by the modal fault detection index. The proposed scheme tic weights updating method, which we have named the Mixed Up- also combines on-line parameter estimation to assure protection dating Technique. The proposed relay is trained using training pattems scheme performance and to achieve adaptive protection. Extensive created by simulating a real 400 kV network from the Spanish trans- simulation studies show that the proposed scheme provides a fast relay mission network (R.E.E.). Finally the proposed relay is tested using response and high accuracy in fault location under various system and simulated and real fault data. The results encourage the use of such fault conditions. The proposed method responds very well with regard technology in protective relaying field. to dependability, security and sensitivity (high-resistance fault coverKeywords: Protective relaying, transmission line protection, arcing age). faults, artificial neural networks. Keywords: Computer relaying, digital protection, global Preprint Order Number: PE-567PRD (04-2002) positioning system (GPS), phasor measurement unit (PMU), transmisDiscussion Deadline: September 2002 sion line protection. Preprint Order Number: PE-644PRD (04-2002) Discussion Deadline: September 2002 Studies for Identification of Inrush Based on Improved Correlation Algorithm Adaptive Nonconmunication Protection Lin, X.; Liu, P; Malik, O.P of Double Circuit Line Systems Author Affiliation: HuaZhong University of Science and Technol- Bo, Z.Q.; Dong, X.Z.; Caunce, B.; Millar, R. ogy; The University of Calgary Author Affiliation: ALSTOM T&D Protection & Control, Ltd.; Abstract: A new scheme based on an improved correlation algorithm to distinguish between inrush and intemal fault in the transformer Tsinghua University, China is proposed. In this scheme, the current over one cycle of each phase is Abstract: This paper presents a new technique for reorganized as a new measurand. Fault currents can be distinguished non-communication protection of double circuit lines. In the technique, 60
IEEE Power Engineering Review, July 2002
