Parallel operation of an inverter with an electrical AC network
IOP Conference Series: Materials Science and Engineering
The paper studies the matters of the interaction of a source of non-sinusoidal current and voltage with a centralized power supply system for the electric energy recuperation during electric braking of rolling stock on the railroads. Revised energy conservation law in electromagnetic field and spectral analysis of non-sinusoidal voltage and current at the output of the inverter have been used to prove the cause of reduced current of RMS voltage in the overhead system. It has been calculated
... been calculated that controlling the active power of recuperation due to the phase shift of the harmonic current components relative to the similar harmonic voltage components is accompanied by a significant increase in the reactive component of the surge current compared to its active component. Losses of active power in the electric stock recuperating heat exchanger make up 83-87 % of the total power loss in the recuperating heat exchanger and in the overhead system. The reactive component of the equalizing current loads the transformers of the traction substations, therefore the voltage on the buses of the substation switchgear decreases. It is proposed to increase the voltage of the overhead system and the traction substation during the recuperation to maintain the minimum phase shift angle of the harmonic components of the nonsinusoidal current relative to the similar harmonic components in the overhead system.