An infrared zero value diagnosis method and system for a porcelain insulator string are provided. The method includes: collecting an infrared thermogram of a to-be-diagnosed porcelain insulator string; extracting temperature of an iron cap of each insulator in the infrared thermogram of the to-be-diagnosed porcelain insulator string; calculating a temperature gradient value of each insulator in the to-be-diagnosed porcelain insulator string, drawing a temperature gradient distribution curve, and generating a temperature gradient distribution matrix of all to-be-diagnosed porcelain insulator strings; calculating a correlation coefficient of the temperature gradient distribution curve and a correlation coefficient of an average-value curve for each insulator string, and presenting the correlation coefficients in a scatter diagram; and performing comprehensive analysis and determining on the temperature gradient distribution curve, the temperature gradient distribution matrix of the to-be-diagnosed porcelain insulator strings, and the scatter diagram, to complete detection of the to-be-diagnosed porcelain insulator string.

A system (10) or method (700) for on-line monitoring of a transformer (10) can include a first sensor (15a) coupled to a primary high voltage side bushing (14a) for monitoring bushing dielectric losses on a high voltage side of the transformer, a second sensor (17a) coupled to a secondary low voltage side bushing (16a) for monitoring bushing dielectric losses on a low voltage side of the transformer, and one or more processors (18) coupled to the first and second sensors. The one or more processors can simultaneously sample (701) data from the first and second sensor, where the primary high voltage side bushing and the secondary low voltage side bushing are operating on a same phase, compare (704) the sampled data over time to provide sampled readings, and generate (706) an alert upon detection of a deviation over a predetermined threshold between sampled readings for the sampled data over time.

An overhead power line insulator is provided including a device for detecting and measuring a leakage current and for transmitting data, the device being arranged in such a manner as to perform: measuring a leakage current of an insulator during a first measurement period and during a second measurement period in a measurement circuit; comparing two values of the current that are obtained during respective ones of the two measurement periods; and stopping the measurement circuit for a certain sleep period of time if the second value of the current is less than or equal to the first value of the current, and then starting the measurement circuit again after the certain sleep period of time.

A method monitors capacitor bushings for an AC mains. The mains has first-third phases, associated with first-third mains lines, capacitor bushings, and mains voltages. Each capacitor bushing has a conductor, surrounded by foil, connecting its mains line. The method includes: at a first instant, for each phase: a first reference voltage phasor is determined; and a foil voltage present between the respective foil and ground potential is detected and a corresponding first foil voltage phasor is determined; at a second instant, for each of the phases: a second reference voltage phasor is determined; the foil voltage is detected and a second foil voltage phasor is determined; for each capacitor bushing: a loss factor change is calculated based on the respective reference voltages and foil phasors and those of the adjacent capacitive bushing; and a monitoring signal is generated based on a comparison of the loss factor and a tolerance value.

The present disclosure relates to an optical fiber detection device for detecting a discharge fault of a high-voltage bushing, which includes an optical fiber sensing unit, an optical fiber delay unit, a photoelectric conversion unit, and a signal collecting and processing unit. The optical fiber sensing unit includes sensing optical fibers; the optical fiber delay unit includes delay optical fibers, a light source, and couplers; the photoelectric conversion unit includes a photodetector; the signal collecting and processing unit includes a high-pass filter. The delay optical fibers are connected to the couplers; an output end of the light source is connected to the light-splitting coupler; an input end of the photodetector is connected to the light-splitting coupler, and an output end of the photodetector is connected to the signal collecting and processing unit; and the light-combining coupler is connected to the sensing optical fibers.

A partial discharge calibration standard apparatus may include a first and second rigid members defining respective first and second facing surfaces. An electrically insulating material may be disposed between the facing surfaces. The apparatus may further include a pressure member maintaining the rigid members together, thereby fixing the first and second facing surfaces in a substantially parallel spaced relation across the insulating material such that a partial discharge threshold magnitude for an electrical potential difference between the first and second facing surfaces is determined. The insulating material may prevent a partial discharge of an electrical potential from the first facing surface to the second facing surface below the partial discharge threshold magnitude, while allowing the electrical potential difference to be discharged from the first facing surface to the second facing surface through the insulating material when the electrical potential difference is increased to the partial discharge threshold magnitude.

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.

The present disclosure relates to an optical fiber detection device for detecting a discharge fault of a high-voltage bushing, which includes an optical fiber sensing unit, an optical fiber delay unit, a photoelectric conversion unit, and a signal collecting and processing unit. The optical fiber sensing unit includes sensing optical fibers; the optical fiber delay unit includes delay optical fibers, a light source, and couplers; the photoelectric conversion unit includes a photodetector; the signal collecting and processing unit includes a high-pass filter. The delay optical fibers are connected to the couplers; an output end of the light source is connected to the light-splitting coupler; an input end of the photodetector is connected to the light-splitting coupler, and an output end of the photodetector is connected to the signal collecting and processing unit; and the light-combining coupler is connected to the sensing optical fibers.

The invention is concerned with a bushing for high voltage applications and a bushing arrangement including such a bushing. The bushing includes a conductor defining a longitudinal axis (A) through the bushing where the bushing has a central section and a first and a second peripheral section on opposite sides of the central section along the longitudinal axis (A) and includes an optical fibre with a first part (P1) stretching through the central section, the fibre being adapted to detect physical properties being influenced or caused by the operation of the bushing. The sections are sections of a solid condenser core and the bushing further includes an enclosure for a length of fibre that is to exit the bushing, the enclosure being buried in the central section adjacent the surface of the condenser core and having an interior.

An approach to detecting partial discharge events involves retrofitting an electrical system to include a capacitive sensor configured to capacitively sense partial discharge events of a component of the electrical system. The capacitive sensor has a first electrical conductor that forms a first terminal of the capacitive sensor, a second electrical conductor that forms a second terminal of the capacitive sensor, and a dielectric that separates the first electrical conductor and the second electrical conductor. The capacitive sensor generates an electrical sensor signal at an output of the capacitive sensor in response to the partial discharge event. The electrical sensor signal is converted to an optical signal and the optical signal is processed to detect an occurrence of the partial discharge event.