Hydro-quebec

Institut De Recherche De L'hydro-quebec

Francois Lalonde

Marius Cloutier

Gilles Missout

Jean-Marc Bourgeois

Jean Marc Bourgeois

Jacques Belanger

The current surge indicator (10) has a ferromagnetic member (12) held about a conductor (15) with the ends of the member (12) in proximity and facing each other such that the ends are attracted to one another with a given force as current passes through the conductor (15). When the force exceeds a given threshold, a signal is created to help in locating where the current surge took place. The member may be spring loaded to open up, and the signal may be provided by the member being released by the current surge such that the member falls from the conductor. The conductor may be an anchor cable of an insulator or tower beam for a power transmission line.

Current surge indicator

An antenna receives, by capacitive effect, a current of which the intensity is a function of the distance separating the antenna from an electrical power line. The other factors that influence the current are fixed, constant or are considered negligible. A measuring and conditioning circuit converts the current at the output of the antenna into a coded signal and transmits this coded signal to a control unit. The control unit compares the coded signal to predetermined values stored therein. Alarms are generated by the control unit when the current from the antenna exceeds the predetermined values.

Alarm system and method for detecting proximity of an object to

A method and an apparatus for the dynamic and non-contact measurement of the distance separating the surface of a first part that may be conductive or not, from the surface of at least one second conductive part closely spaced from the first conductive part. The method resides in positioning, on the surface of the first part, at least one sensor including two conductive plates that are parallel, superimposed and electrically insulated from one another. The two plates of this at least one sensor are then fed with a same high frequency signal under the same voltage and the current generated by this high frequency signal, between the plate of the sensor which is closest to the surface of the second conductive part and this second conductive part, is measured. This measured current varying as an inverse function of the distance separating the surface of the second conductive part from the surface of the sensor which is closest to this second conductive part, it is then easy to determine the value of the distance separating the first and second conductive parts as a function of the value of the measured current. This method as well as the apparatus for carrying it out are particularly well adapted for measuring the air gap in any type of rotating machine such as an electric generator.

Apparatus for the dynamic and non-contact measurement of small distances

A filtering circuit having the behavior of a low-pass filter capable of having a long time constant. The filtering circuit comprises an input circuit for receiving a voltage input signal to be filtered. A summator circuit is provided for monitoring the input signal relative to an analog output signal from an accumulator circuit and providing an error signal representative of the difference of the input and output signals. The error signal is fed to a voltage controlled oscillator to generate a frequency signal proportional to the error signal. The accumulator has a frequency dividing circuit is provided to divide the frequency signal by a predetermined division factor to control the low cut-off frequency of the filtering circuit whereby to increase the response time thereof. The accumulator also integrates the divided frequency signal. An output circuit provides an output of the stored integrated frequency signal to constitute the analog output signal.

Growing community of inventors

Varennes, Canada

Francois Lalonde