Electric Mechinces & Drive
Sh. Yadav; S.K. Mallik; A. Mishra
Abstract
Low Switching-based v/f -controlled induction motor (IM) drives are incredibly susceptible to torque harmonics and their Vibrations. These consequences lead to intensifying losses, damage drive, and can even turn out into shaft failure of high power/speed drives. In literature, numerous control ...
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Low Switching-based v/f -controlled induction motor (IM) drives are incredibly susceptible to torque harmonics and their Vibrations. These consequences lead to intensifying losses, damage drive, and can even turn out into shaft failure of high power/speed drives. In literature, numerous control algorithm based on pulse width modulation (PWM) has been reported for low switching-based IM drive. Nowadays, standard PWM techniques (Sinusoidal PWM (S-PWM), selective harmonic elimination (SHE) PWM) are being used as the solution in low-switching IM drives. In this manuscript, the proposed synchronous reference frame (SRF) based P-PWM scheme is analytically evaluated to minimise the torque harmonics and its vibration in low switching IM drive. In this paper, a specific case of four switching angles per quarter cycle (Sq=4) is considered in which the optimized switching angles are obtained while maintaining the quarter wave symmetry (QWS) and half wave symmetry (HWS) nature of the waveform. The proposed approach is validated on 1hp IM drive and compared with S-PWM and SHE-PWM with respect to torque spectrum and vibration under No Load and different loading conditions. Real-time waveforms are recorded using the SRF-based P-PWM technique and the TYPHOON-HIL hardware setup to demonstrate the superior performance of the SRF-based P-PWM in comparison to S-PWM and SHE-PWM, in terms of lower torque harmonics and their vibrations.
Power System Stability
S.K. Gupta; S.K. Mallik
Abstract
Due to the exponential increase in electricity demand, the power system is being operated at its stability limit. Due to the scarcity of natural resources, the generation can not be increased. Hence, there is always a possibility of voltage collapse in the system. The voltage collapse can be predicted ...
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Due to the exponential increase in electricity demand, the power system is being operated at its stability limit. Due to the scarcity of natural resources, the generation can not be increased. Hence, there is always a possibility of voltage collapse in the system. The voltage collapse can be predicted by a number of line stability indices available in the literature. The stress level of the power system can be mitigated by integrating renewable energy resources, such as wind and solar energy. Under heavy loading conditions, the transmission lines get stressful which can be predicted by line voltage stability indices. In this paper, three line stability indices, namely, Lmn, fast voltage stability index (FVSI), and Lqp are used to identify the most stressed lines under four types of system loadings for ensuring the corrective measure to avoid this voltage instability. These indices are being evaluated using continuation power flow. The system loadability and stability are enhanced by deploying the wind energy and solar PV generation at the most appropriate location. The integrated test system includes wind and solar energy systems at one of the most severe bus, and the performance of the system is confirmed by computing the power flow (PF) using the integrated test system's line indices and the power system analysis toolbox (PSAT). The proposed approach has been validated on IEEE 14 and 118-bus test systems in MATLAB/PSAT with the deployment of wind energy and solar energy at a suitable location.
S.K. Gupta; S.K. Mallik
Abstract
The voltage stability margin (VSM) is an important indicator to access the voltage stability of the power system. In this paper, Flexible AC transmission systems (FACTS) devices like static synchronous compensator (STATCOM), static synchronous series compensator (SSSC), and unified power flow controller ...
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The voltage stability margin (VSM) is an important indicator to access the voltage stability of the power system. In this paper, Flexible AC transmission systems (FACTS) devices like static synchronous compensator (STATCOM), static synchronous series compensator (SSSC), and unified power flow controller (UPFC) have been deployed to enhance the VSM of the power system. The placement of the FACTS devices is decided based on contingency raking. For the top five critical contingencies, the most severe bus is selected based on bus voltage stability criticality index and degree centrality methods. The critical line is decided based on the values of the line stability index, fast voltage stability index, and line stability factor. The STATCOM and shunt part of the UPFC are placed at the critical bus, whereas the SSSC and series part of the UPFC are placed at the critical line for enhancing voltage stability. The proposed method for voltage stability enhancement using FACTS devices is tested and validated on the IEEE-14 bus system and the NRPG-246 bus system at different system loading scenarios. The impact of the placement of FACTS devices is validated in terms of VSM improvement.
