Abstract: A protection system configured to protect plural DC voltage sources configured to be connected in parallel between first and second input terminals of a voltage inverter. The voltage inverter can convert a DC input voltage into an AC output voltage. Each DC voltage source is connected by a first electrical conductor to the first input terminal and by a second electrical conductor to the second input terminal. The protection system includes: for each DC voltage source, a first cut-off member and first detector of a defect of isolation of the first conductor with respect to an electrical ground, the first detector and associated first cut-off member connected in series between the corresponding DC voltage source and the first input terminal of the inverter; and a mechanism triggering, in event of detection of the isolation defect, the associated first cut-off member to open the electrical link corresponding to the first conductor.

Abstract: In this method, the voltage outage load-side is an opening of the circuit breaker, and the circuit breaker is able to interrupt the flow of electric current in an electric connection including an electric conductor. The auxiliary unit comprises a current sensor for measuring the intensity of the current flowing in the electric conductor and a first detection means for detecting the voltage outage load-side from the circuit breaker. The method comprises the following steps: measuring the intensity of the current flowing in the electric conductor, detecting the voltage outage load-side from the electric circuit breaker, determining a cause of the detected voltage outage load-side from the circuit breaker, said cause being selected from the group consisting in: an electric overload, a short-circuit and a voltage drop.

Abstract: This differential protection device is designed for an electric disconnecting apparatus, the disconnecting apparatus comprising at least one fixed contact suitable for being connected to a corresponding electrical conductor, at least one movable contact, between a closed position, wherein it is electrically connected to the corresponding fixed contact, and an open position, wherein it is electrically isolated from the corresponding fixed contact, and an actuator for activating the opening of the movable contacts when a differential fault is detected. The differential protection device comprises a control member for controlling the actuator. The differential protection device further comprises measuring means for measuring an electrical variable associated with the control member and inhibiting means for inhibiting control member when the measured electrical variable satisfies a predetermined criterion.

Abstract: The device according to the invention for estimating the impedance of an ground connection, the ground connection being connected to the ground of an alternating electric network (14) comprising a phase connected to an electric phase conductor and a neutral connected to an electric neutral conductor, comprises: an electrical component having a predetermined value impedance positioned between the phase conductor and the ground connection; a first sensor capable of measuring a first value of a first property between the phase conductor and the ground connection and a second value of the first property; a second sensor capable of measuring a first value of a second property between the neutral conductor and the ground connection and a second value of the second property; and a computation member computing the impedance of the ground connection.

Abstract: The invention relates to an electric arc detection method and device in which: samples of first, second and third filterings are determined, in parallel, for a signal for a current time window and for another time window, a correlation is determined among: a first correlation between said samples resulting from the first filtering and determined for the current window and samples resulting from the first filtering and determined for the other window; a second correlation between said samples resulting from the second filtering and determined for the current window and samples resulting from the second filtering and determined for the other window; a third correlation between said samples resulting from the third filtering and determined for the current window and samples resulting from the third filtering and determined for the other window; and an electric arc is detected as a function of at least said determined correlation.

Abstract: The monitoring device of a neutral conductor and earth conductor comprises processing means, and first voltage detection means to supply a first signal representative of a voltage between neutral and earth to said processing means. The device also comprises second voltage detection means to supply a second signal representative of a voltage between phase and earth to said processing means, and third voltage detection means to supply a third signal representative of a voltage between phase and neutral to said processing means. The processing means supply a loss neutral of signal and/or a loss of earth signal according to the values of the first, second and third signal. The electrical switchgear apparatus comprises such a monitoring device to trigger opening of main contacts.

Abstract: The earth leakage protection device comprises an input designed to be connected to a measuring toroid, a comparator to compare a signal representative of an earth leakage current with a reference threshold, and a processing circuit to command a trip relay for opening main contacts when an earth leakage fault is detected. The device also comprises a signal rectifier receiving at least one signal representative of an earth leakage current, and a filter connected to the rectifier to supply a filtered rectified signal to said comparison means. The electrical switchgear unit comprises main conductors and contacts connected in series, the measuring toroid of the earth leakage current, the relay, and an earth leakage protection device with a matching filter connected to the toroid and to the trip relay.

Abstract: The earth leakage protection device comprises an input designed to be connected to a measuring toroid, a comparator to compare a signal representative of an earth leakage current with a reference threshold, and a processing circuit to command a trip relay for opening main contacts when an earth leakage fault is detected. The device also comprises a signal rectifier receiving at least one signal representative of an earth leakage current, and a filter connected to the rectifier to supply a filtered rectified signal to said comparison means. The electrical switchgear unit comprises main conductors and contacts connected in series, the measuring toroid of the earth leakage current, the relay, and an earth leakage protection device with a matching filter connected to the toroid and to the trip relay.

Abstract: The monitoring device of a neutral conductor and earth conductor comprises processing means, and first voltage detection means to supply a first signal representative of a voltage between neutral and earth to said processing means. The device also comprises second voltage detection means to supply a second signal representative of a voltage between phase and earth to said processing means, and third voltage detection means to supply a third signal representative of a voltage between phase and neutral to said processing means. The processing means supply a loss neutral of signal and/or a loss of earth signal according to the values of the first, second and third signal. The electrical switchgear apparatus comprises such a monitoring device to trigger opening of main contacts.

Abstract: During a first test phase, the device, after detecting the presence of a load, enables the nature of the load to be identified. For this, a control circuit connects the load to an AC main power system, while limiting the current in the load. The device measures several tens of samples of instantaneous values of the load voltage and current during a limited number of half-waves of an AC sine signal and determines the load impedance and the current/voltage phase shift. These characteristics, possibly with complementary parameters derived from the voltage and current measurements, enable the nature of the load to be identified. During a second test phase, the control circuit applies pulses limited in voltage to the load and detects possible short-circuit, differential or overload faults.

Abstract: The device comprises an electronic switch able to temporarily connect a load to an AC power supply system so as to apply the power system voltage to the load during a test phase corresponding to a half-wave of the power system voltage. A control circuit of the electronic switch measures the output current and voltage of the device and calculates the load impedance. It compares the variation of the load impedance during the test phase to curves representative of different types of load. The device performs preventive overload detection by estimating the rated power of the load according to the type of load detected.