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Single line to ground fault at any terminal of a three-phase induction motor blows out the fuse of the faulted phase to disconnect the voltage supply of that phase but the open conductor may remain grounded at the fault point. The motor gets a two-phase supply with the healthy phases connected to the two terminals of the supply while the third terminal of the motor is grounded. Very high negative sequence current is produced at all values of slip. Difference in the magnitudes of current in the three input terminals is small and the single phasing protection fails to operate. In the normal single-phasing condition the open terminal remains isolated from ground. [ABSTRACT FROM AUTHOR]

A negative-sequence current produced during the single-phasing condition of a three-phase induction motor does not allow the motor to start and creates excessive heating while running. To eliminate the negative-sequence current, and thus to operate the motor satisfactorily under a single-phasing condition, the student is to connect a zigzag winding transformer with its star point connected to a system neutral across the motor. This experiment provides a thorough understanding of the sequence network connections under the single-phasing condition of a three-phase induction motor. [ABSTRACT FROM AUTHOR]

The paper presents a new controller design for STATCOM for damping electromechanical oscillations in a power system. The STATCOM is modeled as a reactive current source and the magnitude of this current is obtained by using a sliding mode control strategy. The parameters of the sliding mode controller (SMC) are obtained using linearised model of single-machine infinite-bus power system and a pole placement technique. In order to avoid repeated computation of the sliding mode control gains at different operating conditions, a single neuron controller is used to adapt the parameters of the SMC. Several simulation results are presented to show the marked improvement in transient stability enhancement of the single-machine infinite-bus and multimachine power systems over a wide range of operating conditions. [ABSTRACT FROM AUTHOR]

Abstract. In this paper, colocated, near simultaneous measurements of ocean surface wind speed near the Indian subcontinent from the Special Sensor Microwave/Imager (SSM/I) and Radar Altimeter onboard, respectively, DMSP and Geosat satellites are analysed. It is found that for about 84 per cent of cases, difference of two winds is within 3 m s 1. However, when the colocated winds are averaged for entire period and over the grid boxes of 2.5 2.5 , the correlation between the two winds appears to be very high. It is found that the absolute difference of the two winds has no apparent relation with the amount of water vapour and the amount of cloud liquid water present in the atmosphere. Further, the variations of absolute difference of two winds with SSM/I winds, altimeter winds and significant wave height have indicated that altimeter measurements of high wind speed are likely to be more inaccurate compared to SSM/I measurements. The variation of bias and standard deviation of the difference of the two winds as measured in each 1 m s 1 bin of altimeter wind indicated that the SSM/I wind and the Altimeter wind are in good agreement within 12 m s 1 of altimeter wind, and thus in this range any one can be used in the absence of another. [ABSTRACT FROM AUTHOR]