Abstract: The electrical protection device comprises a plurality of sensors, a multiplexer and a sigma-delta type analog-to-digital converter. The converter comprises a sigma-delta modulator in series with a numerical decimation filter. The decimation filter comprises weighting coefficients ki, of level 1 to n, such that the product of the measuring range of the signals measured by the sensors and of the ratio ∑ l m ⁢ k i / ∑ l n ⁢ k i is less than the precision required for said signals, the coefficients of level 1 to m being the coefficients used during the stabilization time of the modulator. The coefficients of the filter of level 1 to m are preferably zero.

Abstract: The circuit breaker comprises a circuit breaker unit onto which there are fixed a communication module, a processing module and a calibration module. The communication module communicates with the processing module only via a connection with galvanic isolation, preferably an optical connection, whereas the calibration module is electrically connected to the processing module. The communication module is, in addition, connected by a mechanical connection to parts of the circuit breaker unit representative of the state of the circuit breaker, and by a bidirectional electrical connection to an external communication bus. An interface connected to the circuit breaker unit can act as support for the calibration module and for an additional module containing information representative of the breaking capacity of the circuit breaker and electrically connected to the processing module.

Abstract: A system for continuously monitoring electrical conduction of an AC power system comprises at least one measuring module connected between two conductors of the power system. A measuring cycle is divided into two periods. During the first period, the module measures a first DC voltage component, representative of the stray DC components, applied to its terminals. During the second period, the measuring module inputs a DC current component to the power system and measures a second DC component of the voltage applied to its terminals. The difference between the second and first components is used to detect a conduction fault, the line resistance upline from the measuring module being proportional to this difference. The first and second components are obtained by computing the mean value, weighted if necessary, of DC voltage samples measured during measuring periods of a duration lower than or equal to the first and second periods.

Abstract: A reference AC signal having a frequency of about 4-10 Hz is injected into a line of a DC electrical network for performing insulation measuring in a processing unit. The AC signal is measured in a mixed bridge having a first resistive dividing bridge connected in parallel with a second capacitive dividing bridge between the line and the ground. The intermediate output points of the first and second bridges are joined together and connected in an input of the processing unit. The impedance and the dividing ratio of the two bridges cause the DC voltage measured at said input to be low in relation to the value of the AC voltage measured at the output of said mixed bridge.