Analysis and simulation of line notching attenuation for a static excitation system in a power system

Abstract

This paper presents measurements of power quality indices for a static excitation system composed of a transformer and a controlled rectifier bridge in a power system generator group and the corresponding MATLAB/Simulink simulation. Replacing the old auxiliary excitation generator eliminates the disadvantage of using electrical machines with inertial moving masses and wear over time, but with the price of facing two important problems: the line voltage notching due to thyristor switching and the line current distorting. Theoretical aspects of line notching and several solutions for compensation strategies (and their limitations) are discussed. The MATLAB/Simulink model made possible the implementation of the solution selected to deal with these problems and to evaluate its effectiveness based on the results.

Performance comparison between active and passive power filters for a static excitation system in a power generator group: A MATLAB/Simulink approach

“…The main requirement for an active power filter (APF) is to mitigate harmonics, but reactive power compensation and load balancing is also possible for those with shunt type. APF power factor compensation is continuous, rapid, and transient free [6].…”

“…It is mandatory to install the shunt APF system before the line reactors, in order to avoid the zero crossing points of voltages. The reducing of notches in phase voltages leads to the reducing of the high dv/dt variations, and therefore the active filter becomes more efficient in reducing the current distortions [6]. The only problem with active filters is the switching ripple caused by the inverter switching which can cause EMC emissions, but with an effective low power RC switching ripple filter this can be avoided.…”

PQ versus EMC problems at a static excitation system in a power group

“…It is mandatory to install the filtering system before the line reactors, in order to avoid the zero crossing points of voltages. Reducing the notches in phase voltages results in reducing the high dv/dt variations, thus the active filter being able to reduce current distortion more effective [9], [10]. The only problem with active filters is the commutation ripple caused by inverter switching which can cause EMC emissions, but with an effective low power RC switching ripple filter this can be avoided.…”

Some Considerations Regarding the Measurement of the Compensation Efficiency in Three-Phase Systems

“…The greatest of them refers to the injection of current harmonics (and consequently of voltage harmonics) in the PSN, with unpleasant effects over the operation of some equipment and over the entire network. Unfortunately, there is no universal solution for this, instead solutions for particular cases (or solutions adopted such as to be applicable to an entire group of loads or equipment) were conceived [2,[19][20][21][22][23]. The adopted solutions refer to the use of active filters (shunt or series, depending on application) and/or hybrid filters, owing to the advantages provided by them as compared to the use of passive filters [19,24].…”