Resumen
Method and system for estimating the frequency of an alternating current electrical network that feeds a direct current railway electrical system, where the method comprises: measuring a waveform of a direct current voltage source of the railway electrical system; determine a ripple frequency of the waveform of the direct current voltage source, and; obtain an instantaneous frequency value of the electrical network by quotient of the ripple frequency of the waveform of the direct current voltage source between the number of pulses of at least one rectifier that connects the direct current voltage source with the electrical network. (Machine-translation by Google Translate, not legally binding)