Experimental Study and Comparative Analysis of Transients of Induction Motor with Soft Starter Startup (original) (raw)
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[2]Practical Analysis of Harmonics Effects on Transformer
Harmonic currents or voltages are generated from a non-linear load when it is connected to the mains supply. The problems caused by harmonic include overheating of cables, especially the neutral conductor, overheating and vibration in induction motors and increased losses in transformers. In this paper, the details analysis of harmonics effect on a 1KVA transformer is analyzed. A frequency oscillator source is used for generating the harmonics signal on the transformer. The total harmonic distortion, crest factor and Kfactor are analyzed by using a Fluke-435 power analyzer.
Practical Analysis of Harmonics Effects on Transformer
Harmonic currents or voltages are generated from a non-linear load when it is connected to the mains supply. The problems caused by harmonic include overheating of cables, especially the neutral conductor, overheating and vibration in induction motors and increased losses in transformers. In this paper, the details analysis of harmonics effect on a 1KVA transformer is analyzed. A frequency oscillator sourceis used for generating the harmonics signal on the transformer. The total harmonic distortion, crest factor and K-factor are analyzed by using a Fluke-435 power analyzer
Experimental study on the impact of harmonics on transformer
2013 IEEE 7th International Power Engineering and Optimization Conference (PEOCO), 2013
Impacts of harmonics on step-dow presented in this paper. Transformer failure h due to harmonic current causing excessive win rise. Excessive temperature rise of transfo harmonic effect result in higher power l operating mode. An experimental setup is prop for observation of harmonics. This researc transformer losses under nonlinear load with consumption. Moreover, the trends of Total Ha (THD) with nonlinear load are reported.
Power Quality Studies on a Soft-Start for an Induction Motor
Three-phase induction motor of ratings beyond 50 kW take very large low power factor currents while being started directly from a 3-phase supply. Normally softstarts are used for avoiding this problem and to achieve smooth starting of large capacity induction motors. A 3phase AC voltage controller is employed as a soft-start. But, this takes harmonic-rich current especially while operating at large firing angles. In this paper, the effect of inserting a shunt active filter to provide harmonic and reactive power compensation in a soft-start has been studied. The shunt active filter has been inserted between the AC voltage controller and power supply to take care of the reactive power requirement of the motor and AC voltage controller and also to provide harmonic compensation. Both simulation hardware studies have been done on a 22 kW induction motor with and without soft-start arrangement. The shunt-active filter uses the IcosĪ¦ control algorithm for calculating the compensation currents. The results with the insertion of shunt active filter show a substantial reduction in the current drawn from the source and its harmonic content. This will be a very useful scheme especially in industries where multiple induction motors of large capacity are frequently started from a 3-phase supply.
IEEE Transactions on Industry Applications, 2000
In order to mitigate the adverse effects of starting torque transients and high inrush currents in induction motors, a popular method is to use electronically controlled soft-starting voltages utilizing series-connected silicon-controlled rectifiers (SCRs). Investigation of semioptimum soft-starting voltage profiles was implemented using a flux linkage ABC frame of reference model of a soft-started three-phase induction motor. A state-space model of the soft-starter thyristor switching sequence for the motor and load was developed and implemented in a time-domain simulation to examine winding heating and shaft stress issues for different starting profiles. Simulation results of line starts and soft starts were compared with measured data through which validation of the model was established. In this paper, different induction machine soft-start profiles are shown, and comparisons of starting times, torque profiles, and heating losses are made. Discussion of these results and conclusions as to the near-optimum types of profiles are delineated based on peak torque, starting times, and winding heating criteria.
The Induction Motor; a Short Circuited Rotating Transformer - A Comparative Analysis
With the advent of transformer, which encourages the atmost universal adoption of a.c system of transmission/distribution of electric energy, the field of application of induction motor has widened considerably in the recent years. Consequently, electrical machine manufacturers have endeavoured, over the years to perfect various types of a.c motors and transformers, suitable for all classes of domestic and industrial appliances and for both single and three phase a.c supply. As a.c electrical machines, transformers and induction motors share related/distinct characteristics. The idea of the induction motor seen as a generalized transformer is the object of our discussion.
Two-phase induction machine dynamic model in a coordinate system which rotates at synchronous speed and one-mass dynamic model of mechanism driven in relative units describing transient processes when starting an induction machine in case of constant load conditions are developed.The influence of equivalent circuit parameters of induction machine and mechanism parameters on impact currents and torques and starting time of common used induction machines is studied by means of design of experiment method.
Determination of the Harmonic Losses in an Induction Motor Fed by an Inverter
Engineering, Technology & Applied Science Research
The advancement, development, improvement, and increased use of power electronic converters led to the efficient speed control of electrical drives. The most famous three-phase induction motor-related control to Pulse-Width Modulation (PWM) technique is used to operate multilevel inverters such as variable-frequency or six-step Voltage Source Inverter (VSI). Switching devices of the inverter are used in the drive systems and act as the main source of harmonics. When the induction motor is fed from the PWM inverter, it will be supplied by low order (5th, 7th, 11th) time harmonic voltage. The motor performance is affected by the presence of these time harmonic components because the additional losses generated in the motor defect its performance, generate pulsating torque, and reduce efficiency. In this work, the analysis of a dynamic model of an induction motor in transient and steady-state operation is developed, considering the effect of time-harmonic voltages generated by the inve...
Harmonic effects on induction and line start permanent magnet machines
8th International Conference on Energy Efficiency in Motor Driven Systems (EEMODS 2013), 2013
Power Electronics (PE) are implemented in a wide variety of appliances, either to increase its controllability or energy efficiency, or simply because a DC supply is needed. The massive integration of rectifiers has resulted in a decrease of the supply voltage quality. Although PE have enabled the end user to control electrical machines, the resulting distortion inversely affects Direct On-Line (DOL) machines. In this paper a review is presented of the influence of these supply anomalies on Induction Motors (IM). The suggested problems have already been subject of much study. However, as new DOL technologies are emerging, for example Line Start Permanent Magnet Machines or Induction Generator systems, the influence of supply distortion on these systems should also be considered. This paper will present a comprehensive overview of the loss mechanisms, the magnitude of the losses and the impact of these losses on operation of IM, LSPMM and IG.
The review and analysis the destructive effects of harmonics on a sample MV/LV transformer
IET Conference Publications, 2009
Considering the effects of non-liner loads to create harmonics and replacing these loads instead of household, commercial and industrial customers, create many voltage disturbances every year. Harmonics will cause specific problems in the power distribution networks. Some of these problems could be unsuitable function of equipments from these networks, decreasing their lifetime and their efficiency. Therefore, we need to study harmonics and show the way to resolve these problems. Limiting harmonics is very important for utility companies and their subscribers. Utility companies must provide against to damage on subscribers from these problems. Since Utility companies could not guarantee a sine wave to protect their subscribers from voltage disturbances; therefore, these subscribers must limit their disturbances of their equipments. One statistics indicated twenty-five percent of transformers utilized in the utility companies of Iran have about eighteen year's lifetime only. So, maintenances of transformers in the utility companies become very important. Once we replace one of these transformers, we need to analysis its malfunction. The study of malfunction will provide us with a reasonable solution. Therefore, we are trying at this paper to show why we need to study the effects of harmonics on transformers of power distribution networks. The effects such as increasing load and no-load power losses, reducing the power of transformers and Destructive Effects create more heat in them. Consequently, we identify and record harmonics on a sample load and calculate Destructive Effects that created in its transformer by these harmonics, at this condition, be increase the transformer's heat by non-liner loads, to cause its insulation life decrease as well as transformer life.