The invention relates to a
pulse width modulation based
cathode protection method. The
pulse width modulation based
cathode protection method comprises the following steps: firstly, connecting a buried pipeline facility by adopting a
pulse width modulation polarization power supply; secondly, setting a
cathode protective potential to a predetermined value; thirdly, generating a pulse width modulation
signal according to cathode protective potential value; fourthly, driving the pulse width modulation polarization power supply by the pulse width modulation
signal; fifthly,
measuring output voltage of the pulse width modulation polarization power supply,
measuring output current of the pulse width modulation polarization power supply; sixthly, measuring cathode protective potential, relative to a
reference electrode, of the buried pipeline facility; a pulse width modulation based cathode protection device is characterized in that the pulse width modulation polarization power supply is connected with an output current measuring device and an output
voltage measuring device, the pulse width modulation polarization power supply is connected with a buried facility, an auxiliary
anode and an on-off controller, a
control circuit is connected with a feedback
signal controller by virtue of a protective potential setting device, and a cathode protective potential measuring device is connected with a buried
reference electrode by virtue of a
copper sulphate
reference electrode impedance converter, so that size is small and control accuracy is high.