Mitigation of Capacitor Bank Energization Harmonic Transients
In the present study, an overview of the capacitor bank energizing transients is presented and the means of harmonic mitigation technique are investigated. Capacitor bank connection is essential due to reactive compensation reasons. Transients produced upon of capacitor bank energizing, reach in harmonics, may be harmful for the capacitor and become an increasing concern for both electric utilities and customers since its switching usually occurs quite frequently. We know that power factor correction capacitors are sensitive to harmonics and one factor of the failures of power capacitors indicates the prime odd harmonics like 5th, 7th, 11th, 13th harmonics. A time domain simulation using PSCAD/EMTDC was performed to predict the harmonic spectrum of the distorted voltage waveform in a real 11 kV Romanian distribution subsystem
Mitigation of capacitor banks switching transients considering injected harmonics
Installing capacitor banks in electric power systems provide well known benefits, including reactive power compensation, voltage support and power factor correction. However, the capacitor banks modify the harmonic voltages and currents in the network and give rise to current and voltage transients. These transients, reach in harmonics, may be harmful for the capacitor and become an increasing concern for both electric utilities and customers since its switching usually occurs quite frequently. In this paper, firstly, transients caused by capacitor bank switching for a specific part of Uraemia (IRAN) Power Network which has recently been installed in 132kV level, especially from the view point of harmonic spectrum and THD (Total Harmonic Distortion) are analyzed and contemplated. After that, the role and effect of some common methods in harmonic spectrum and THD mitigation are contemplated and compared.
Minimal transient switching of capacitors
Capacitor banks are used to compensate the reactive power demand of large commercial and industrial loads. When used to switch capacitor banks mechanical breakers generate large current transients. These transients may cause serious system disturbances, premature wear of the breaker contacts and, possibly, shorten the life of the capacitors. While thyristor switches are not new and industry has successfully used them to obtain transient-free switching of capacitor banks, there are very few papers describing this application. This paper tries to fill the void and presents a comparative study of various three-phase configurations of semiconductor switches intended for low voltage (600 V and less) distribution systems. Simple theoretical analysis enables the calculation of the optimal switching times to minimize transients. These calculations take into account the system impedance and the initial capacitor voltages. >