Abstract: A high-voltage bushing has an insulator, which contains an insulating gas and an insulating solid, and an inner conductor which is led through the insulator. A mounting flange is employed for the mounting of the high-voltage bushing on a wall. A sensor, which is arranged on the mounting flange and is configured for the detection of at least one reaction product of the insulating gas and/or of the insulating solid. A corresponding method monitors an operating state of the high-voltage bushing.

Abstract: 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 Cx, 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 Fx. 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: ?CX=CX?CX+1, for all values up to, and including, ?CN?1, ?CN=CN?C1, for ?CN, ?FX=FX?FX+1, for all values up to, and including, ?FN?1, ?FN=FN?F1, for ?FN, and determining whether the ?-values are within predefined ranges.

Abstract: The present disclosure relate to a fault diagnosis method, including: collecting at least one set of original data of the high voltage generator during operation, each condition attribute in a condition attribute set corresponding to one piece of original data; pre-processing the original data to obtain pre-processed data and generating a decision table; performing an attribute reduction based on the decision table to obtain a reduced condition attribute set and a reduced decision table; generating a decision tree model according to the reduced decision table; generating a decision forest model according to at least one decision tree model; obtaining a fault type and a fault level according to the decision forest model; determining an acceptable level of the fault according to the fault level and a frequency of occurrence of the same type of fault, and sending the fault type and the acceptable level to the display terminal.

Abstract: A high-voltage test terminal includes a first conductor, a second conductor, and a primary insulator disposed between and coupled to the first and second conductors. A blade is movably connected to the second conductor. The blade is electrically and mechanically connected to the first conductor in a first position and electrically isolated and mechanically disconnected from the first conductor in a second position. A guard insulation layer is disposed between the primary insulator and the first conductor.

Abstract: A method of determining the capacitance and loss-factor of each of a plurality of capacitive components of an electrical power device, wherein the method includes: a) obtaining for each capacitive component a respective capacitance value and loss-factor value, and b) processing the capacitance values and the loss-factor values, wherein the processing involves removing a common influence of temperature on the capacitance values from the capacitance values and removing a common influence of temperature on the loss-factor values from the loss-factor values to obtain for each capacitive component a temperature-compensated capacitance value and a temperature-compensated loss-factor value.

Abstract: A friction-flow piercing apparatus for piercing very deep and fine holes is described, that relies on a novel support method for the piercing means. An apparatus for monitoring during the piercing process to determine the electrical properties gradient of the substrate is further described, particularly for meltable dielectric such as plastic industrial equipment. A permanently installed piercing means may function as a permanent test site.

Abstract: An inspection apparatus for inspecting high voltage insulators is disclosed. The inspection apparatus includes a first platform having first and second linkages, at least one outer gripping mechanism having first and second arms extending outwardly from the first platform, a second slidable platform adapted to slide along the first and second linkages, and at least one inner gripping mechanism having third and fourth arms extending outwardly from the second slidable platform. The outer and inner gripping mechanisms are adapted to move between an open position where the insulator is received by the outer and inner gripping mechanisms and a closed position where the outer and inner gripping mechanisms engage the insulator.

Abstract: The voltage at the test tap of a high voltage bushing is applied to a bushing coupler which includes circuitry to sense and process voltages generated at the test tap and convert the voltages into corresponding data signals. Data signals corresponding to the test tap voltages are then transmitted wirelessly to a bushing monitoring system. The wireless transmission may be, for example, via an optical coupling (e.g., fiber optics) arrangement or an electromagnetic radiation (e.g., RF transmission) arrangement. Thus, the signals from the bushing coupler are wirelessly transmitted to a monitoring system which is not conductively connected to the bushing coupler and the test tap. The bushing coupler includes a power supply which is chargeable from the test tap or wirelessly from the bushing monitoring system which is adapted to receive values of the high voltage applied to the bushing and to calculate changes in the values of selected bushing parameters.

Abstract: A high voltage test terminal for an electrical power distribution/transmission system includes a shock-absorbing insulator disposed between first and second conductors. A blade is movably connected to the second conductor. The blade is electrically and mechanically connected to the first conductor in a first position and electrically isolated and mechanically disconnected from the first conductor in a second position. The blade is in the first position for normal operation of the electrical apparatus. The blade of the test terminal is moved to the second open position to conduct both electrical and mechanical tests of the electrical apparatus.

Abstract: There is provided a test method for detecting the presence or absence of a defect in a spark plug insulator, including a reference voltage determination process, a test area determination process, a test voltage determination process and a current detection process. In the reference voltage determination process, a reference voltage VF is determined. In the test area and voltage determined processes, test area and voltage are determined so as not to incur a flashover on the basis of a reference insulator of the same material, shape and size as the spark plug insulator when the reference insulator is placed in position between first and second test electrodes. In the current detection step, the test voltage is applied between the first and second test electrodes to detect an electric current between the first and second test electrodes.

Abstract: The invention relates to a method for monitoring a capacitor bushing (1) to which an electrical operating voltage (UB) is applied and in which a voltage divider is formed with an electrically conductive insert (4), whereby at least one measured value (UM1) of an electrical measured quantity (UM) is recorded and stored by using a measuring tap (7), which is connected to the insert (4), and by using each potential. The aim of the invention is to improve the method so that it is only slightly influenced by changes in the operating voltage. To this end, the impedance (ZE) between the measuring tap (7) and the earth potential is modified after recording the at least one measured value (UM1), and at least one signal value (US1) of a measurement signal (US) subsequently formed is recorded and stored using the measuring tap (7) and the earth potential.

Abstract: The digital protection system for a high voltage electricity network to instruct circuit breakers to open in the event of faults being detected by current and/or voltage sensors on the network lines 4 connected to the circuit breakers. The digital protection system includes an infrared data transmission link with a portable telephone. Transmissions between the digital protection system and the portable telephone uses the wireless application protocol WAP.

Abstract: The present invention provides a method and device for detecting a discharge in an electrical device comprising, providing a bushing having a bottom lower flange and a top upper flange, providing a shield inside the bushing extending from the bottom lower flange to a position at least below the top upper flange and providing an antenna outside the bushing at least above the position for measuring an output signal from the device for detecting the discharge.

Abstract: An electrical system and a sensor for on-line monitoring of the state of high-voltage insulation in the electrical system. In this arrangement, the signals associated with partial discharge activity are monitored and transmitted from the sensor to monitoring instrumentation. The sensor is interconnected with the potential stress shield of existing bushings. The capacitance in the bushing between the main conductor and the stress shield conducts partial discharge current which is available for being sensed.

Abstract: A sensor and associated circuits are provided for on-line monitoring of the state of the high-voltage insulation in electrical equipment with capacitance tap. In this arrangement, both the power frequency signal and the radio frequency signals associated with partial discharge activity are sensed. These signals are transmitted from the sensor to remote monitoring instrumentation via one connecting cable. The sensor contains a surge arrester in parallel with a capacitor shunt, a radio frequency current transformer and a connecting circuit. The polarity terminal of the primary winding of the radio frequency current transformer is connected to the tap output. The non-polarity terminal is connected to the common connection point of the surge arrester and the capacitor shunt while the second terminals of these components are connected to the local ground.

Abstract: An insulated device diagnosing system is capable of judging the deterioration, lifetime, and defects of a device. The intensity at each voltage phase angle is measured at a plurality of specific frequencies, taking high voltage phase angles as the abscissas. The deterioration, lifetime, and the kind and extent of abnormality of the device are judged from the pattern and intensity of the spectral distribution, which is obtained by peak-holding the measured intensity for a defined time period. According to the present invention, partial discharge can be measured highly sensitively and precisely to diagnose the deterioration, lifetime and the extent of defect of the device. As a result, the insulation reliability of the device can be improved, and the part of the device that should be repaired/replaced can be grasped before disassembly of the device, thereby cutting the maintenance cost.

Abstract: The method of this invention provides a means for altering commonly available inductive voltage detector instruments into dual sensitivity test instruments. By shielding the sensor probe with a metallic material, the probe is made to be unresponsive to energized conductors in near proximity when the shield is grounded by finger contact. A single probe window is provided so that when grounded, the instrument will respond to an energized conductor in only the probe window area allowing testing of single conductors in wire bundles. When ungrounded by the electrician's finger, the instrument reverts to normal sensitivity. Provision is made for safety by isolating the metallic shield from contact with energized conductors. The method may be employed by means of a demountable accessory or incorporated into the test instrument during manufacture.

Abstract: A method of detecting faults on a cable (1) is provided, such a cable (1) having a conductive path, there being a number of sensors (5a, 5b, 5c, 5d, 5e) along the length of the cable (1), each of the sensors shaving a resistance measurement device for detecting the cable to ground resistance of the respective section of the cable (1). The cable to ground resistance at the respective sections are measured and compared with a predetermined value, and if the cable to ground resistance of any one particular section is less than the predetermined value, it is determined that a fault is present in that section.

Abstract: A group of bushings receives voltage in parallel to produce a current output from each bushing. Cumulatively combining the current outputs from the bushings vectorially furnishes a vector sum bushing current. Reference voltage devices also produce reference current outputs. Cumulatively combining the reference current outputs vectorially provides a vector sum reference current, and differentially vectorially combining the vector sum reference current with the vector sum bushing current delayed by 90° provides a difference signal representative of a bushing condition. As an alternative to the reference voltage devices, a second group of bushings may be used. In this case, a delay of 90° is not required. The invention may also be used to monitor the condition of other capacitive devices, for example, high voltage current transformers.

Abstract: In a measurement system for electric disturbances in a metalen-capsulated high-voltage switchgear having at least one measurement probe for each phase for decoupling of electromagnetic interference signals, both the interference signals and the useful voltage are scanned by the same measurement probe in each phase, and both are made accessible, separately from one another, at a filter arrangement.

Abstract: A bushing for an electrical high-frequency signal, with at least one conductive element carrying the electrical high-frequency signal, with at least one mechanical supporting element and with at least two insulating elements between the conductive element and the supporting element that perform different functions. The bushing for an electrical high-frequency signal is designed so that the impedances of the insulating elements are basically identical.

Abstract: A remote contamination sensing device for contamination on insulation of electric power lines and substations includes a data logger and a supporting structure to which a sensing capacitor with at least two conductors is attached such that the conductors are spaced apart and insulated from each other. A capacitance measuring device, for measuring capacitance data between the conductors, is connected to the data logger. A hygrometer, for measuring the relative humidity of the ambient air, is also connected to the data logger. A first temperature sensor, for measuring the ambient temperature, and a second temperature sensor, for measuring the surface temperature of the capacitance sensor, are connected to the data logger. The measured capacitance data, relative humidity data, ambient temperature data, and surface temperature data are stored in the data logger.

Abstract: An accurate dielectric breakdown prediction method and a prediction method in which accurate time dependent dielectric breakdown (TDDB) characteristics can be obtained on the basis of dielectric breakdown prediction by a step stress method are provided. In this method, dielectric breakdown is predicted on the basis of a plurality of reference currents in accordance with an applied voltage, or a reference current I.sub.cr is varied as the function of the applied voltage. In the step stress TDDB prediction, a Chen-Holland-Hu model or improved Chen-Holland-Hu model is employed. Since TDDB characteristics can be obtained from only dielectric breakdown prediction, this method is advantageous for early reliability prediction.

Abstract: An apparatus for detecting a partial discharge in a high voltage transformer comprising a live tank comprises a metal box detachably connected to the tank; a first acoustic sensor inside the box for converting acoustic waves in a first frequency band to a first electrical output signal; signal conditioning circuitry inside the box for amplifying and filtering the first electrical signal; an electrical to optical converter, inside the box, for converting the amplified and filtered electrical signal to an optical signal; a fiber optic link for carrying the optical signal to a location remote from the transformer; and an optical to electrical converter at the remote location for converting the optical signal to a second electrical signal, the second electrical signal being indicative of a partial discharge inside the tank. The second electrical signal may be fed to an oscilloscope or recording equipment for determination of the occurrence of a partial discharge.

Abstract: A method and apparatus for verifying the condition of an electrical insulator which is placed between two live conducting elements which are separated by the insulator. The insulator has a continuous electrically insulating core that may be covered with other types of insulating material. The insulator may also be a lightening arrester consisting of stacked insulating discs. An electric field detecting apparatus is positioned at a plurality of locations along the insulator to measure the intensity of an electric field created along the insulator. At each location a detected signal value of the electric field is stored within the apparatus and all of these signals are analyzed to detect deviations from expected values of the electric field and indicative of a fault(s) along the insulator.

Abstract: The apparatus comprises a probe-insulator (3) with an internal cavity, a first system (8/1) that circulates a cold fluid within the cavity (4) of the probe-insulator in order to cool the latter to such a temperature that the external humidity condenses on the external surface, a second system (8/2) for measuring the surface conductivity on the probe-insulator, a third system for activating a washing plant of all insulators installed in the same area when the measured value of said surface conductivity reaches a pre-set critical value; the refrigerating device that produces said cold fluid preferably includes a group of Peltier modules.

Abstract: A device for detecting and indicating a fault current flowing through a lightning arrestor or an insulator, the current being DC or at AC mains frequency, the device being housed inside a box that is provided with a frangible window and that has a piece of metal electrically connected to an end fitting of the lightning arrestor or of the insulator passing therethrough. The device has: a transformer for transforming the current, the primary of the transformer being constituted by the piece of metal, and the secondary of the transformer being connected to a peak-limiting circuit to make pulses of current due to surges corresponding, in particular, to lightning strikes inoperative; a heating resistance fed by said transformer and constituting an igniter for a pyrotechnic composition in which it is embedded, the composition being designed to break the frangible window; and preferably indicator means suitable for being released by rupture of the frangible window.

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: 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: An apparatus for detecting faulty power line insulators of the suspension type on an energized power line by comparing two adjacently mounted insulators in series. The apparatus is generally made like a three-prong fork. Each prong has a metal tip forming a probe adapted to conductingly straddle two adjacently mounted insulators. The lateral prongs are each connected to the central prong through a high voltage resistor and an ammeter. Comparison of the amperages registered by both ammeters indicates the existence of a faulty insulator.

Abstract: An apparatus for detecting degradation of a grounded arrester, including a wave conversion circuit for producing an output signal corresponding to the total leakage current flowing through the arrester, and a phase shifter circuit coupled to the output signal for providing a capacitive-component leakage current signal, which is cancelled from the total leakage current signal by means of a differential amplifier to produce a resistive-component leakage current signal. According to one embodiment, this latter signal is applied to a synchronous rectifier circuit for synchronous rectification of the output signal from the differential amplifier circuit. A real resistive-component leakage current signal is then detected by adjusting the phase shift amount in the phase shifter circuit so that the output signal from the synchronous rectifier circuit may become zero, thereby bringing the phase of the cancelling wave signal in agreement with the phase of the capacitive-component leakage current signal.

Abstract: A method and apparatus for detecting defective insulators in an insulating column supporting an electrical conductor in a power line. The column is made of a plurality of serially connected insulator members. Voltage present on the conductor supported by the column generates an electric field about it. The presence of faulty insulators within the column causes field redistribution and discontinuities in it. A specially configured electric field probe is provided to measure at predetermined distance and locations, this electric field. A displacement device is provided whereby to displace the probe along an axis substantially parallel along the length of the column to automatically obtain measurements. Means to analyze the measurements are provided and allow to identify the defective insulators whose positions correspond to the locations of the discontinuities in the electric field surrounding the column. The main advantage of this method is that no electrical contact need to be made to the insulators.

Abstract: A method is provided for utilizing a nonintrusive, noncontacting electric field sensing device to detect faults in high voltage transmission line insulators. The electric field surrounding an unfaulted insulator is mapped using a spherical dipole to obtain a characteristic reference curve. The field of a suspect insulator is then mapped to obtain a test curve which is compared with the reference curve to determine the existence of and location of a fault.

Abstract: The present invention teaches a technique and provides for apparatus eminently useful for the continuous, simultaneous monitoring of the insulation quality of one or more pieces of high voltage ac electrical equipment, while the equipment is in service and connected to its normal high voltage source. The technique or method of the instant invention involves comparing a voltage, developed across a capacitive shunt at the capacitance tap of a transformer or bushing so equipped with a reference voltage taken from a voltage transformer or potential device connected to the same high voltage source.