Schlumberger Industries

Electricite De France

Enertec S.a.

Service National and Enertec

Alain Carnel

Bernard Patry

David J Clarke

Rene Gourc

Rudolph Kodras

Alain Chiffert

An electrical measuring device utilizing a shunt, an electronic measuring circuit floating at the potential of the shunt and a first voltage divider connected between the shunt and a neutral point to provide a first voltage signal to the circuit. To obtain the benefit of decoupling the potential between the shunt and the intermediate point of the first voltage divider, the device includes an additional terminal connected to the shunt by a second voltage divider, whose intermediate point supplies a second voltage signal used differentially with the first.

Electrical device for measuring electrical parameters

The invention relates to an input circuit for an electrical energy meter, which circuit has a current path and a voltage path, the current path being associated with a mutual conductance transformer. In order to compensate for the differentiating function of the transformer, but without introduicng interference signals, the current path includes an active filter connected as an integrator and provided with a coupling capacitance suitable for blocking low frequency signals.

Input circuit for an electrical energy meter

A device for remote metering, comprising a meter (4) for measuring a consumption, a transmission circuit for transmitting information relating to quantities consumed, and consisting essentially of a modulating circuit (5,6) and of a bifilar line (3), and a counter circuit for counting sets of information. The modulating circuit comprises a capacitive network (6) and at least one switch (5) which is actuated by the meter and which is capable of modifying the capacity of the capacitive network. The device further comprises a circuit (7,14) suitable for evaluating the value of the capacity of the transmission circuit, and thus for distinguishing two states of the modulating circuit and one state of a fault in the line. Such a device is, in particular, usable for the remote metering of a consumption of gas or of electricity.

Device for remote metering

A modulator for injecting signals into a polyphase power transmission system includes a bridge of four thyristors for each phase. The thyristors of each bridge are connected so that when the thyristors of two opposite arms are ignited simultaneously they produce a signal at the output from the modulator of opposite sense to the corresponding signal when the thyristors of the two other opposite arms are ignited. The thyristors of the adjacent arms are controlled in opposition and coupled by an induction coil having two windings which, through the back EMF generated by mutual inductance, causes the extinction of one of them when the other is ignited. The energy stored in the induction coil at the time of the extinction phase is dissipated as heat in a resistor provided for this purpose in a loop which does not contain the supply.

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Poitiers, France

Alain Carnel