Method of monitoring an electrical network, in particular a medium- or high-voltage network, for differential protection, the method comprising: measuring, at a first point in time determined according to a master clock, a first current value (25, 27) by means of a first device at a first location in the network and assigning the first point in time; obtaining, at a second device, the first current value (25, 27) and the assigned first point in time; and comparing the first current value (25, 27) with a second current value (29, 31), which was measured at a second location in the network and has been assigned to the first point in time according to the master clock, the obtaining, at the second device, of the first current value (25, 27) and the assigned first point in time comprising: sending the first current value (25, 27) and the assigned first point in time in a telegram, which has further first current values and assigned further first points in time, from the first device to the second device, in particular by way of an electrical cable connection of a communication network between the first device and the second device, characterized in that for each measurement, the telegram comprises the current value, the point in time and a validity bit, which indicates whether time synchronization was available, the comparing of the first current value with a second current value comprising: checking whether there is a validity bit both for the first current value and for the second current value. measuring, at a first point in time determined according to a master clock, a first current value (25, 27) by means of a first device at a first location in the network and assigning the first point in time; obtaining, at a second device, the first current value (25, 27) and the assigned first point in time; and comparing the first current value (25, 27) with a second current value (29, 31), which was measured at a second location in the network and has been assigned to the first point in time according to the master clock, the obtaining, at the second device, of the first current value (25, 27) and the assigned first point in time comprising: sending the first current value (25, 27) and the assigned first point in time in a telegram, which has further first current values and assigned further first points in time, from the first device to the second device, in particular by way of an electrical cable connection of a communication network between the first device and the second device, characterized in that for each measurement, the telegram comprises the current value, the point in time and a validity bit, which indicates whether time synchronization was available, the comparing of the first current value with a second current value comprising: checking whether there is a validity bit both for the first current value and for the second current value. for each measurement, the telegram comprises the current value, the point in time and a validity bit, which indicates whether time synchronization was available, the comparing of the first current value with a second current value comprising: checking whether there is a validity bit both for the first current value and for the second current value.