An apparatus to locally monitor, and report to a remote monitoring system, specific physical conditions of equipment that provide early indication of failure conditions, including but not limited to: temperature, level of fluids, pressure, temperature, the presence of gases or airborne particulate, and signs leaks.

The present invention relates to a method and monitoring device, for monitoring N number of transformer bushings operating in substantially the same environment. N being any number more than 1. The method comprises estimating an absolute value for the capacitances of each of the bushings, the absolute values for the capacitances being denoted C.sub.x, and estimating an absolute value for the loss factor or the power factor of each of the bushings, the absolute values for the loss factors or the power factors being denoted F.sub.x. X is a number representing which bushing the value is associated to and X larger than 1. The method further comprises calculating -values for all C values and -values for all F values, according to:
C.sub.X=C.sub.XC.sub.X+1, for all values up to, and including, C.sub.N1,
C.sub.N=C.sub.NC.sub.1, for C.sub.N,
F.sub.X=F.sub.XF.sub.X+1, for all values up to, and including, F.sub.N1,
F.sub.N=F.sub.NF.sub.1, for F.sub.N,
and determining whether the -values are within predefined ranges.

Insulation monitoring may be provided by a signal generation unit for applying a pulse signal to an electric line; a signal measurement unit for measuring the voltage of an applied pulse signal from the ground, when the pulse signal is applied to the ground through insulation resistance; an average voltage calculation unit for calculating the average voltage of the voltages measured during a period depending on sampling intervals; and a control unit for calculating the sampling intervals on the basis of an initial sampling interval and a preset time multiple, calculating the average voltage during the sampling period according to the calculated sampling intervals, and, according to whether the difference between calculated first and second average voltages measured before the first average voltage is within a first error range, detecting the first average voltage as a normal voltage, or calculating the sampling intervals by applying different time multiples thereto.

A partial discharge signals processing method includes: setting a first discrimination criterion among the following criteria: discharge signals acquisition, discharge signals noise filtering, and discharge signals classification; providing a plurality of pulse waveforms associated with detected partial discharge waveform signals; defining at least a first reference pulse waveform in accordance with the first criterion; performing a first training of a neural network module based on the at least a first reference pulse waveform to produce a similarity index adapted to selectively assume a first value and a second value representative of a similarity/non similarity of an input pulse waveform with the at least a first reference pulse waveform, respectively; comparing the plurality of pulse waveforms with the at least a first reference pulse waveform by means of the neural network module to obtain first similarity index values; and memorizing/rejecting each compared pulse waveform on the basis of the obtained first similarity index values and on the second discrimination criterion.

An apparatus and method measures and analyzes DC current passing through a substantially insulating member or dielectric material that is electrically connected to, or otherwise conductive, between an energized DC electrical transmission line and an Earth potential or ground. An apparatus may utilize a DC current measuring device, a DC voltage level selection switch, a DC display, a graphical display of momentary leakage current, and an audio speaker. A process may entail extending a substantially insulating member or dielectric material between an energized DC electrical transmission line and an Earth potential, detecting a DC momentary leakage current, using a DC momentary leakage current meter to measure DC current through the member or material, and a computer to analyze and compare the DC current, and deliver results or a warning that the DC current has reached a threshold value.

An insulator leakage current detector, an insulator leakage current detecting system, and a method of monitoring insulator leakage current using the same are provided. An insulator leakage current detector mountable on an insulator string includes a sensor to sense leakage current information of the insulator string; and a device to send a signal including the leakage current information sensed by the sensor.

A circuit testing apparatus includes at least one resistance wire enclosed in a housing and connectable to a pole of a power distribution system having at least one isolation device therein. The resistance wire has electrical conductivity, length and diameter such that a maximum current in the resistance wire at initiation of burn through of the resistance wire is above a trip current of the at least one isolation device and below a current sufficient to damage any component along the pole of the power distribution system. In some embodiments, the housing includes a vent arranged to enable escape of heated gas therefrom and prevent escape of any hot particles resulting from burn through of the resistance wire.

A system for monitoring transformer bushings sensors, wherein first and second bushing sensors are connected to a common first phase of a high voltage source, and the third and fourth bushing sensors are connected to a common second phase of the high voltage source. A first time series is generated from the first and second bushing sensors during a predetermined time interval. A second time series, is generated from the third and fourth bushing sensors during the predetermined time interval. A correlation model for the first and second time series for determining a difference between a measured signal and an estimated signal, and generating a signal indicative of a bushing problem the difference is larger than a threshold.

An overhead power line insulator comprises a dielectric element (4) having an outside surface forming a skirt (5) with a head extended by a metal attachment fitting (7) for attaching the insulator, and a device for detecting surface leakage current flowing on the dielectric (4), the device comprising a conductive ring (8) that surrounds the fitting (7) and that is in contact with the outside surface of the dielectric (4). An electrically insulating protective element (10) is provided in the form of a collared bushing that surrounds the fitting (7), being interposed between the ring (8) and the fitting (7) and extending radially so as to overlie the ring (8) in order to protect it from environmental pollution.

An apparatus and method measures and analyzes DC current passing through a substantially insulating member or dielectric material that is electrically connected to, or otherwise conductive, between an energized DC electrical transmission line and an Earth potential or ground. An apparatus may utilize a DC current measuring device, a DC voltage level selection switch, a DC display, a graphical display of momentary leakage current, and an audio speaker. A process may entail extending a substantially insulating member or dielectric material between an energized DC electrical transmission line and an Earth potential, detecting a DC momentary leakage current, using a DC momentary leakage current meter to measure DC current through the member or material, and a computer to analyze and compare the DC current, and deliver results or a warning that the DC current has reached a threshold value.