Methods and systems detect short circuits in an electrical system, such as a dynamic braking grid of a vehicle. The methods and system measure a characteristic of a current that is conducted through one or more resistive elements of an electrical system. The current is supplied to the electrical system from a power source as an applied voltage. A resistance change signal representative of a change in one or more electrical resistances of the one or more resistive elements is determined The resistance change signal can be based at least in part on a difference between the characteristic of the current that is measured and a low pass filtered value of one or more of the characteristic of the current that is measured or the applied voltage supplied by the power source. A short circuit event is identified based at least in part on the resistance change signal.