Abstract: A partial discharge (PD) transducer that includes a PD sensor configured to sense a PD event of an electrical system. At least one light emitting device (LED) is arranged in series with the PD sensor. The LED is configured to receive the electrical sensor signal from the PD sensor and to generate a light signal in response to the electrical sensor signal.

Abstract: A method for characterizing the dielectric response of a fluid includes receiving the fluid into a portion of a flow line that is disposed proximate to a photonic bandgap (PBG) resonant cavity so that a dielectric permittivity of the fluid affects a frequency response of the resonant cavity. The method further includes providing electromagnetic waves to the resonant cavity and measuring a frequency response of the resonant cavity in the presence of the fluid in the flow line. The method further includes determining a property of a resonant mode of the resonant cavity using the frequency response and determining a property of the fluid using the property of the resonant mode.

Abstract: In a rotating electrical machine, a conductive foil or conductive rubber is applied to the surface of insulation layer of a conductor series connection area or to the surface of insulation layer of a turn conductor of coils of rotating electrical machine winding, waveforms of grounding voltages of the individual turn conductor portions are measured through the medium of an electrostatic capacitance of the insulation layer of coil conductor series connection area or through the medium of the insulation layer of coil turn conductor, and a partial discharge is measured while measuring a voltage developing in the coil or across a winding turn in the coil from a difference between the waveforms of grounding voltages.

Abstract: A device (1) for assessing the corrosion of the transformer windings in an oil-insulated transformer comprising a copper conductor (2) immersed in the oil. The change of the resistance of the copper conductor (2) over time is measured, e.g. using a Wheatstone bridge (2, 12a, 12b, 12c), and used to assess the degradation of the copper exposed to the insulation oil. The temperature of the copper conductor can be controlled by an heating element and a temperature sensor.

Abstract: A method for deriving the concentration of a gas dissolved in an electrical insulating oil (2) comprises the following steps:—preparing a membrane (5) permeable to the gas, interposed between a container (7) of the oil (2) and a measuring chamber (4) that receives a part of the gas through the membrane (5);—measuring the value of gas concentration in the measuring chamber (4);—deriving an estimated value of the concentration of the gas in the oil (2) as a function of the measured value,—the measuring step comprising taking at successive measuring instants a plurality of measurements of the values of gas concentration in the measuring chamber (4);—the deriving step comprising calculating the estimated value of gas concentration in the oil (2), at an instant selected from said measuring instants, according to a non-linear function of the values measured at the selected measuring instant and at one or more of the measuring instants preceding the one selected.

Abstract: A diagnostic method and apparatus for assessing the insulation condition of electrical equipment (3) insulated with oil (2). The method comprises the following steps: measuring the concentration of at least one gas dissolved in the insulating oil (2) of the electrical equipment (3); deriving at least one concentration parameter correlated with the gas concentration measured in a predetermined acquisition time interval; measuring electrical pulses relating to partial electrical discharges which occur in the electrical equipment (3) and which generate said pulses; deriving at least one discharge parameter correlated with the partial discharges measured substantially concurrently with the predetermined acquisition time interval; deriving a diagnostic indication about the insulation condition of the electrical equipment (3) as a function of the derived values of the concentration and discharge parameters.

Abstract: Method and device for measuring a dielectric response of an electrical insulating system, wherein a first measurement result is determined by a frequency domain method and a second measurement result is determined by a time domain method, whereupon the first measurement result and the second measurement result are combined to form an overall measurement result as the dielectric response. Standard types of measurement methods, for example the FDS and PDC methods, may be used as measurement methods for the frequency domain and the time domain.

Abstract: A method for determining quality and condition of a highly resistive fluid in transportation and industrial equipment. The method uses apparatus that applies a multitude of oscillating voltage signals at determined frequencies and offsets to electrodes immersed in the fluid and quantifies fluid response to the signals. The method monitors response of the fluid to a preferred three fixed electrical signals applied by the apparatus, a high and a medium frequency signal with zero offset voltage and a low frequency signal with an offset voltage. For apparatus or applications where the monitored fluid is not controlled to constant temperature, the method includes correcting the temperature sensitive fluid responses for temperature variations for the fluid quality and condition determination. The method can also include determining when essentially complete fluid exchanges are made to the equipment without need for additional input.

Abstract: A method and device for detecting partial discharges in an electrical apparatus placed in a tank filled with oil, wherein the tank wall is provided with at least one drain tap. The device includes a probe mounted on a carrier that is movable through the opened drain tap into the tank. To move the probe into the tank while avoiding leakage of the oil, a sleeve maybe coupled to a flange of the drain tap an the carrier may be moved within the sleeve. The probe may be moved so that it at least coincides with the inner surface of the tank wall, or even further, and then measurements may be performed to detect partial discharges.

Abstract: A materials characterization test cell is disclosed. The test cell includes a housing including spacers for supporting sample insulation materials, and a channel disposed in the housing to permit the passage of oil through the housing. A pair of electrodes is provided to provide a mechanism for making polarization spectrum and/or streaming electrification measurements.

Abstract: A lubricating/hydraulic fluid condition monitor in which a coaxial microwave resonator is placed in a fluid conduit to determine changes in the chemical properties and debris concentration is disclosed. Microwave radiation is applied to the resonator for measuring the resonant frequency and resonator Q. An externally powered electric or magnetic field is used to alternately align and misalign debris in the fluid while the resonator properties are being measured. A logic unit automatically generates tables of resonant frequency and Q versus resonator mode and external field strength. This set of tables constitutes a fingerprint of the fluid condition. By matching the fingerprint against a set of fingerprints taken under known conditions, the condition of the fluid is determined.

Abstract: A sensor installable within a gas turbine engine for sensing electrostatic charge therein. The sensor comprises a sensing plate and first and second shielding plates. The sensing plate has a first face with a first peripheral portion, and a second face with a second peripheral portion. The first and second shielding plates are spaced from and positioned relative to the first and second faces of the sensing plate, respectively, by a layer of electrically insulating material, so that electrostatic charge in the proximity of the sensor is sensed by both the first and second peripheral portions of the sensing plate.

Abstract: A method and apparatus for detecting the degree of deterioration in lubricating oil including a grid-like capacitive sensor, that uses the lubricating oil as a dielectric medium, and a magnetic field imposed upon the oil to attract ferromagnetic wear particles into the vicinity of the sensor. Preferably, the magnetic field is generated by a permanent magnet and an electromagnet aligned such that the magnetic field produced by each magnet acts upon the oil along the same axis. A plurality of capacitance measurements are taken at periodic intervals for one type of classification and analysis. Magnetically induced particle concentrations are analyzed visually under the aid of periodic magnetic flux reorientation and optical magnification.

Abstract: A metal particle detecting sensor (10), having a simple structure, can perform in-line analysis for metal particles in fluid and also can precisely estimate or detect the number of metal particles for each particle size. Metal films (1) and insulating films (2) are alternately laminated one upon another, and every other metal film (1) in the laminate is connected in parallel with one another to one of two lead wires (3a, 3b) so as to form comb electrodes in the laminate of the sensor, and one end face of the laminate is immersed in a fluid (4) containing metal particles so as to detect the metal particles.

Abstract: A chip detector is an open circuit device that attract metal chips circulating throughout a piece of equipment such as a transmission. If a chip closes the circuit in the chip detector, then it is subjected to a first pulse of energy in an attempt to burn or displace it from the chip detector contacts. The energy content of the first pulse is selected to burn fuzz, which represents chips of an acceptable size. If the chip remains in the chip detector, then it is subjected to one or more additional pulses each having a greater energy content than the first pulse. The number of pulses and their energy contents are recorded to determine the size of the chips captured by the chip detector and to provide a history of the equipment being monitored. If the chip in the chip detector exceeds a predetermined threshold, then an indication is given on a user interface.

Abstract: A degradation level of transformer insulating oil can be checked by measuring leakage current of a sensor for measuring the degradation level of the insulating oil, in which DC power is applied to two electrodes of the sensor in the insulating oil for the transformer. In general, free carbons or nonsolute conductive particles are produced in the transformer insulating oil when used over long periods in the power transformer. The porous ceramic of the sensor for measuring degradation level of the insulating oil receives in the pores thereof the conductive impurity particles, and a conductive circuit is formed. Thus, this measurement for degradation level of insulating oil is based on the electric change states for the formation of the conductive circuit. Accordingly, by forming such structures, a method and apparatus for measuring degradation level of insulating oil by measuring leakage current of the sensor are provided.

Abstract: A method for determining transient partial discharges in the insulating medium of an electrical power transformer, for example, oil and paper, uses in one embodiment a circular plate inserted in the interior of a transformer tank which picks up partial discharge signals. These are high frequency transients which are processed by use of DC notch filters, blocking capacitors and amplified by high frequency amplifiers. The peaks of the partial discharge signal are detected by peak amplifiers, sorted by relative magnitudes, and either displayed or further processed by computer techniques for indicating incipient transformer failure.

Abstract: Apparatus for detecting the sufficiency and quality of an amount of dielectric material contained in the cavity of a transformer bushing is disclosed. The apparatus comprises a collar assembly which when placed over the bushing forms a capacitive element, a tunable signal producer for applying a signal to the capacitive element, a circuit for receiving, amplifying and rectifying the output signal from the capacitive element, and an indicator to detect and indicate the dielectric condition or capacitance of the capacitive element and thus the sufficiency and/or quality of the dielectric material within said bushing assembly. The collar assembly in one embodiment comprises a pair of electrically conductive segments which are hinged together for positioning about the bushing. The interior surfaces of the collar assembly are shaped to conform substantially to the outer shape of the transformer bushing.

Abstract: An apparatus for detecting the degree of deterioration in lubricating oil including a grid-like capacitive sensor, that uses the lubricating oil as a dielectric medium, and a magnetic field imposed upon the oil to attract ferromagnetic wear particles into the vicinity of the sensor. Preferably, the magnetic field is generated by a permanent magnet and an electromagnetic aligned such that the magnetic field produced by each magnet acts upon the oil along the same axis.

Abstract: Apparatus for detecting the sufficiency and quality of an amount of dielectric material contained in the cavity of a transformer bushing is disclosed. The apparatus comprises a collar assembly which when placed over the bushing forms a capacitive element, a tunable signal producer for applying a signal to the capacitive element, a circuit for receiving, amplifying and rectifying the output signal from the capacitive element, and an indicator to detect and indicate the dielectric condition or capacitance of the capacitive element and thus the sufficiency and/or quality of the dielectric material within said bushing assembly.

Abstract: A portable tester is disclosed for determining in the field the condition of a lightning arrester connected in parallel with a high voltage winding of a transformer. The tester comprises a battery; an inverter connected to the battery for generating an AC output; at least one transformer and a rectifier for transforming the output of the inverter to a high voltage DC having a magnitude greater than the breakdown voltage of a lightning arrester connected in paralled to the high voltage winding of a transformer being tested; at least one capacitor connected across the rectifier for being charged to the high voltage DC; an overvoltage spark gap switch for discharging the high voltage charge of the capacitor across the high voltage winding of the transformer being tested; and a storage oscilloscope for detecting the response of the winding to the high voltage pulse. A normally functioning lightning arrester will clamp the voltage across the transformer winding at the arrester's known breakdown point.

Abstract: A static induction electric apparatus includes an oil tank, an electrical winding assembly, an insulating oil for cooling and insulating the winding, and a circulating pump. A sensor electrode having a measurement surface for providing an electrical signal indicative of the amount of the electric charge in the insulating oil is supported on the oil tank by a support assembly in such a relationship that the measurement surface of the sensor electrode is electrically insulated from and substantially flush with the inner surface of the oil tank. The distance between the sensing surface of the electrode and the inner surface of the oil tank is large enough to electrically insulate the two from one another but small enough to keep the electric field around the sensor electrode free of substantial disturbances.

Abstract: A method in which ionization associated with fine wire or solid electrode systems causes mist droplets to charge and collect on electrode surfaces or at a region of highest electrical stress. The method includes manipulating droplet clouds to reach high stress regions. This process achieves improved electrical strength by depositing a mist in optimum locations before voltage applications.

Abstract: The density of charge entrained in fluids such as oils in transformer systems, capacitors, cables, pumps and fuel transfer systems is measured by introducing the oil into a conductive container which expands in volume to receive the fluid without expelling any fluid. The container is shielded by a grounded conductor which prevents inducement of charge on the container by external sources. By measuring the current between the conducting expandable container and the surrounding shield and accounting for the effects of the charge induced on the outer wall of the container by its own induced voltage, the net charge entrained in the fluid as it is brought into the container is deduced. Extraneous effects of conduction and electrokinetic currents are automatically excluded from the measurement. The oil is then automatically returned to the transformer system by the contraction of the conductive container so that the measurement can be repeated without accumulating an inventory of fluid.

Abstract: A method for partial discharge detection and breaking spark measurement in a dynamo-electric high-voltage machine, especially for monitoring insulation status during operation of a stator winding and connected electrical output lines in a turbo-generator. The generator includes a stator having a stator winding and a stator housing, a rotor with an exciter winding and a shaft, defining an air gap between the rotor and the stator. At least one oil lubricated slide bearing supports the shaft of the rotor with a bearing shell being electrically insulated from the ground. The method includes decoupling the frequency spectrum of high-frequency electromagnetic oscillations resulting from the occurrence of partial discharges or breaking sparks and delivering the frequency spectrum of high-frequency electromagnetic oscillations to a partial discharge measurement apparatus.