There is provided an electrical power system comprising: a DC voltage source, a DC electrical network, a DC to AC to DC converter having a primary side connected to the DC voltage source and a secondary side connected to the DC electrical network, and a controller configured to control the DC to AC to DC converter, wherein the controller is configured to: monitor an electrical current or voltage between the DC voltage source and the DC electrical network; determine, based on the monitored electrical current or voltage, whether the DC electrical network is in a fault condition; and increase a switching frequency of the primary side of the DC to AC to DC converter in response to a positive determination that the DC electrical network is in a fault condition.