Abstract: Apparatus for remote monitoring of partial discharge events in electrical apparatus 1 includes one or more sensors 5 for detecting partial discharge pulses in one or more conductors 2 conveying electrical power to the apparatus. A programmed computer 5 analyses measured pulses and discriminates between those originating from the apparatus being monitored and elsewhere. Discrimination is achieved by analysing pulse shape, and by comparing pulses to partial discharge events measured locally to the sensors. The apparatus enables partial discharge events in electrical apparatus to be monitored without having to install sensors at the equipment itself.

Abstract: The invention relates to a method and a device for determining a maximum leakage current in unearthed power supply networks with a plurality of conductors. The method comprises the steps of: feeding of a measurement signal UP with a measurement frequency fPuls into a conductor arrangement, setting the measurement frequency fPuls, measuring a line-to-line voltage UL-E for each conductor, determining a maximum occurring line-to-line voltage UL-Emax from the measured line-to-line voltages UL-E, determining a voltage UZe across a measurement resistance RM for calculating a leakage impedance ZE, calculating the leakage impedance ZE, and calculating a maximum leakage current THC. The device comprises a signal generator for feeding in the UP with the fPuls, a network coupling circuit between the signal generator and the conductor arrangement, a voltage measuring circuit for measuring the UL-E, and an impedance measuring circuit for determining the Ze by means of the determining of the UZe.

Abstract: There is provided a fault detecting apparatus for detecting a fault in an electric circuit including connecting circuits and an aggregating circuit. The fault detecting apparatus includes a fault detector that detects a fault when at least one of connecting circuit current detectors detects that a current flows and an aggregating current detector detects that a current does not flow.

Abstract: An insulation state detection circuit includes a first charging circuit, a second charging circuit and a third charging circuit. A charging resistance value in the case that a capacitor is charged in the first charging circuit coincides with a charging resistance value in the case that the capacitor is charged in the second charging circuit when a resistance value of the ground fault resistor of a negative terminal side of a DC power source is a ground fault alarm threshold value for an insulation state of an alarm level. The charging resistance value of the first charging circuit coincides with a charging resistance value in the case that the capacitor is charged in the third charging circuit when a resistance value of the ground fault resistor of the positive terminal side is a ground fault alarm threshold value for an insulation state of an alarm level.

Abstract: A test circuit for detecting a leakage defect in a circuit under test includes a test stimulus circuit operative to drive an otherwise defect-free, characteristically capacitive node in the circuit under test to a prescribed voltage level, and an observation circuit having at least one threshold and adapted for connection with at least one node in the circuit under test. The observation circuit is operative to detect a voltage level of the node in the circuit under test and to generate an output signal indicative of whether the voltage level of the node is less than the threshold. The voltage level of the node being less than the threshold is indicative of a first type of leakage defect, and the voltage level of the node being greater than the threshold is indicative of a second type of leakage defect.

Abstract: Provided is an apparatus for analyzing the state of oil-filled electrical devices. The apparatus simulates the state of an oil-filled electrical device in which copper wire wrapped in insulating paper is immersed in insulating oil. The apparatus for analyzing the state of oil-filled electrical devices includes a first paper-covered copper wire and a second paper-covered copper wire, which are adjacent to each other; a tank which holds the first and second paper-covered copper wires as well as insulating oil extracted from the oil-filled electrical device, thereby immersing the first and second paper-covered copper wires in the insulating oil; and a capacitance measurement unit which measures the capacitance between the first and second paper-covered copper wires. The first and second paper-covered copper wires includes copper wire and insulating paper wrapped therearound.

Abstract: A low cost fault detection and protection method and embodiment circuit can detect short circuit faults between an inverter system control (ISC) circuit outputs and a chassis, an electrical machine winding and a chassis, and a DC bus and a chassis. A fault protection unit (FPU) can monitor chassis voltage with respect to a DC bus to detect the presence of a short circuit fault, and provide status output indication of whether a fault is detected. By way of example, an FPU can include a window detector and a signal transmitter. An FPU can provide status output to an ISC controller configured to terminate ISC operation when any of the aformentioned faults is present, thereby preventing damage to devices contained in the ISC circuit.

Abstract: A connection diagnostic apparatus for a ground fault detector including an oscillator connected via a coupling capacitor to an electric circuit with a first connection line and a second connection line, and a voltage detector for detecting a voltage value between the oscillator and the coupling capacitor is provided with a first relay and a second relay provided in the first connection line and the second connection line, and a programmable controller. The programmable controller determines a connected state of the ground fault detector based on a change amount of a voltage value detected by the voltage detector when the first relay is turned on or off and determines the connected state of the ground fault detector based on a change amount of a voltage value detected by the voltage detector when the second relay is turned on or off.

Abstract: A Ship Board Ground Monitor System measures an antistatic bond between a ship and a loading-off-loading facility during operation and an earth ground while in the process of loading or unloading flammable materials. The system ensures that a maximum adjustable, preset resistance between the ship transport and safety ground is not exceeded. Should this resistance be exceeded, the control apparatus within the system will activate audible and visual annunciation and provide a contact output, which may be used to disable pumping systems.

Abstract: The present techniques include methods and systems for detecting the grounding condition of an electrical system to automatically determine a suitable electrical drive configuration. The drive includes a test resistor which may be connected or disconnected from the drive to measure different drive voltages. The measured drive voltages are analyzed to determine a type of grounding configuration of the electrical system in which the drive is to be installed. Embodiments also include determining ground resistance condition such as a high resistance ground (HRG) fault or a ground resistance fault when the drive is in operation.

Abstract: Test system and method comprise a controller, which can be microprocessor derived and include operating system for programmability, to control low voltage signals and feedback for managing the test system. High potential test system can include an amplifier comprising solid-state and/or passive components amplifying lower voltage signal to produce higher voltage output signal based on signal monitoring and control provided by controller. Controlled higher voltage output signal can be injected into high voltage multiplier circuit resulting in high DC voltage output voltage up to 50 kV or higher range. The monitoring can include feedback indicative of higher voltage signal output of amplifier and/or high DC voltage output voltage of high voltage multiplier circuit. System feedback and control can be fully automated, or selectively user-controlled via a user interface providing continuous and/or selective monitoring and display of system parameters and measured signal inputs and/or outputs.

Abstract: Medical devices and methods for making and using the same are disclosed. An example medical device may include a control unit for determining an electrical leakage between a first electrode pad and a second electrode pad of an in vivo medical device. The first electrode pad may be spaced from the second electrode pad. The first electrode pad may have an active electrode and a spaced ground electrode. The second electrode pad may have an active electrode and a ground electrode. The ground electrode of the first electrode pad may be electrically connected to the ground electrode of the second electrode pad.

Abstract: There is provided a grounding detection device and method. The grounding detection device may include an insulation tester and a grounding resistance providing unit. The insulation tester may be mounted in a first cabinet, electrically connected to a positive busbar and a negative busbar to detect an equivalent busbar-to-ground resistance, and grounded via the first cabinet. The grounding resistance providing unit may be mounted at least in part in a second cabinet different from the first cabinet, electrically connected to at least one of the positive busbar and the negative busbar to provide a grounding resistance, and grounded via the second cabinet. The insulation tester may determine, based on resistance values of the equivalent busbar-to-ground resistance and the grounding resistance, whether there is a ground fault or not for the insulation tester, the first cabinet, and the second cabinet.

Abstract: A mechanism is described for determining whether or not a ground connection is properly earthed by determining whether or not a potential difference exists between a voltage measuring point and a ground connection. A first capacitor is connected between the ground connection and a first power line and a first duplicating capacitor (having the same capacitance as the first capacitor) is connected between the voltage measuring point and the first power line. If the determining step determines that the potential difference does not exist, then it is determined that the ground connection is not properly earthed.

Abstract: This technology is directed to a method and apparatus for monitoring or testing defects associated with an ion lens connected within a mass spectrometer. In some implementations, the testing mechanism monitors a connection of one or more ion lenses configured in the mass spectrometer to determine if voltage is effectively applied to the ion lens. The testing circuit of the present technology includes at least one Zener diode added to the voltage divider and monitoring a change in slope of the applied voltage versus the voltage at the read-back circuit. The change in slope may be easily measured.

Abstract: In a ground fault detection device, two photovoltaic strings are disconnected from a photovoltaic power generation system, measurement for one photovoltaic string is performed by a measuring instrument, and in parallel therewith, the other photovoltaic string before measurement is charged/discharged by a charging/discharging unit by executing various functions of the calculation control unit. In other words, charging/discharging of the photovoltaic string is performed in advance at the same timing as the measurement of the photovoltaic string so that the measurement can be performed immediately after the photovoltaic string is connected to the measuring instrument in a subsequent step.

Abstract: A fault detection system for a machine having a plurality of electrical conducting elements insulated from a frame ground of the machine is disclosed. The fault detection system may include a high voltage DC power source, a positive high voltage bus connected to a positive terminal of the high voltage DC power source and providing high voltage electrical power to the plurality of electrical conducting elements, and a negative high voltage bus connected to a negative terminal of the high voltage DC power source and returning high voltage electrical power from the plurality of electrical conducting elements. At least one of the positive and negative high voltage buses may be selectively connected through a plurality of switches to plural zones of the electrical conducting elements, with each of the plural zones being electrically connected in parallel, and selectively connected to the high voltage DC power source by one of the plurality of switches.

Abstract: The leakage resistance detection device includes a coupling capacitor having one terminal connected to an on-board high voltage device and another terminal connected to a repetitive signal output circuit, and measures a leakage resistance as a function of a transition time during which a monitoring voltage, which is a potential at the another terminal of the coupling capacitor to be charged/discharged in response to an operation of a charge/discharge switching element that operates in response to a repetitive pulse signal, changes from one predetermined voltage to reach another predetermined voltage. When the measured leakage resistance has become equal to or smaller than a predetermined limit leakage resistance, the leakage resistance detection device generates a resistance abnormality determination output.

Abstract: A ground fault detection circuit comprising a fuse and a fuse detect circuit. The fuse and the fuse detect circuit are arranged to be coupled in parallel between a reference point and a second point of a monitored circuit for which ground faults are to be detected. The fuse detect circuit is further arranged to detect a fuse break indicative of a ground fault condition and disable at least a portion of the monitored circuit.

Abstract: A first predetermined point of a photovoltaic circuit insulated with respect to a ground is grounded to the ground by a first electrical ground path, a first direct current voltage value is applied to the first measurement point by a first direct current power supply, and a first current value flowing in the first electrical ground path is measured in this state. Further, a second predetermined point of the photovoltaic circuit insulated with respect to the ground is grounded to the ground by a second electrical ground path, a second direct current voltage value different from the first direct current voltage value is applied to the second predetermined point by a second direct current power supply, and a second current value flowing in the second electrical ground path is measured in this state.

Abstract: The present disclosure discloses a voltage source for calibrating a very fast transient voltage measurement system, comprising a DC high voltage power supply, a discharging gap, a high voltage travelling wave line concluding a high voltage conductor and an earthing conductor. The present disclosure also provides a method for calibrating a fast transient voltage measurement system: the high voltage conductor is insulated from the earthing conductor, and is open circuit at one end and at the other end is connected with the earthing conductor via the discharging gap, applying a high voltage between the high voltage conductor and earthing conductor and making breakdown of the discharging gap, a very fast transient high voltage is produced on the high voltage conductor and its waveform can be determined by theoretical calculation, the very fast transient high voltage with known waveform is used as the calibration voltage for calibrating the measurement system.

Abstract: In a ground fault detection device, two photovoltaic strings are disconnected from a photovoltaic power generation system, a measurement of a first voltage value is performed for the one photovoltaic string by a first measurement unit, and in parallel therewith, a measurement of a second voltage value is performed for the other photovoltaic string by the second measurement unit by executing various functions of a calculation control unit. Thus, a capacitance relative to a ground of a measurement target is reduced. Further, the photovoltaic string is electrically separated from a load device at the time of such a measurement. Further, separate measurements are performed on the one and other photovoltaic strings in the disconnected state, and the first and second voltage values are measured in parallel.

Abstract: A method is provided for detection of a ground fault in a high resistance network in a voltage source power conversion circuit comprising a power converter that converts incoming AC power to DC power applied to a DC bus and an inverter that converts DC power from the DC bus to output AC power. The method includes detecting a midpoint-to-ground voltage between a low side of the DC bus and a ground potential and detecting the presence of a ground fault in a high resistance network based upon the detected midpoint-to-ground voltage.

Abstract: A design for test (DfT) architecture is provided that enables pre-bond parametric testing of through-silicon vias (TSVs). A grouping of N number of input/output (I/O) segments are configured to receive a test signal in a feedback loop, where each I/O segment includes one or more buffers (or inverters) and a TSV connected at one end to the one or more buffers. The TSV acts as a shunt-connected capacitor—when defect free—and includes a load resistance when the TSV contains a defect. Each I/O segment can also include one or two multiplexers to control whether the I/O segment receives a test or functional signal and, optionally, whether the I/O segment is bypassed or included in the ring oscillator. The varying loads caused by the defects cause variations in the delay across the buffers (or inverters) of an I/O segment that can be detected in the output signal.

Abstract: An arc fault circuit interrupter is disclosed. This arc fault circuit interrupter can include any one or more of three different sensors such as a high frequency sensor, and any one of lower frequency sensors such as a current sensor or a differential sensor. The arc fault circuit interrupter can be configured as an in line arc fault circuit interrupter installed in a wall box. In addition, the arc fault circuit interrupter can include a processor configured to determine any one of a series arc fault, or a parallel arc fault.

Abstract: A ground fault detection circuit includes: a first switch circuit that connects/disconnects a first path between a positive bus bar and a ground potential section, the positive bus bar being connected to positive electrodes of secondary battery units through a field-effect transistor including a parasitic diode; a second switch circuit that connects/disconnects a second path between a negative bus bar and a ground potential section, the negative bus bar being connected to negative electrodes of the secondary battery units; and a ground fault detection unit that detects a ground fault of the positive bus bar or the negative bus bar based on an electric current flowing through the first path or the second path.

Abstract: A method for determining a circuit element parameter in a ground fault circuit interrupter circuit. An electrical signal provided to a first node is used to generate another electrical signal at a second node. The electrical signal at the second node is multiplexed with a modulation signal to generate a modulated signal that is then filtered and converted into a digital representation of a portion of the circuit element parameter. The electrical signal at the second node is multiplexed with the modulation signal after it has been phase shifted to produce a modulated signal that is filter and converted into a digital representation of another portion of the circuit element parameter. In another aspect, a slope based solenoid self-test method is used for self-testing in a GFCI circuit. Alternatively, a method for determining a wiring fault is provided using a digital filter.

Abstract: Disclosed herein are systems and methods for identifying a fault type in an electric power delivery system using an angle difference between a total zero-sequence current and a total negative-sequence current and a comparison of phase-to-phase currents against a threshold. The angle difference falls into one of a number of predetermined angle difference sectors. Each sector is associated with a phase-to-ground fault type and a phase-to-phase-to-ground fault type or two phase-to-phase-to-ground fault types. The phase-to-phase current(s) of the indicated phase-to-phase-to-ground fault type(s) associated with the sector are compared with a threshold to determine which of the fault types of the sector is the actual fault type. The threshold may be a multiple of a maximum phase-to-phase current.

Abstract: An active continuous DC power supply insulation malfunction detection circuit includes a leakage current detection unit, a positive voltage terminal compensation unit and a negative voltage terminal compensation unit respectively at a positive voltage terminal and a negative voltage terminal of the power supply system. The positive and negative voltage terminal compensation units include respectively a one-way discharger and a power source unit that are forward conducted. The invention can improve the shortcoming of the conventional detection techniques that use passive elements for detecting ground insulation deterioration by letting the power source unit discharge through the one-way discharger so that the leakage current detection unit can continuously detect and measure current variations passing through the positive and negative voltage terminals without interruption, and thereby easily obtain leakage current value and provide active and continuous detection of ground insulation deterioration.

Abstract: A process and apparatus for performing a ground fault test of a device is disclosed. A current level may be selected from a plurality of predetermined current levels. A ground fault current may be generated between a first power line and a ground at the selected current level until a ground fault interrupter within the device trips, or until expiration of an on-time period associated with the selected current level. The ground fault current may then be set to zero for an off-time period associated with the selected current level. The process may be repeated for each of the plurality of current levels. When the ground fault interrupter within the device trips, the current level and a time interval from an onset of the ground fault current at the selected level and a time when the ground fault interrupter tripped may be recorded.

Abstract: A current transformer is provided. The current transformer comprises an inner magnetic core having a central opening, an outer sense core circumscribing the inner magnetic core, at least one pair of conductors extending through the central opening and positioned symmetrically with respect to a center point of the inner magnetic core, and one or more coils disposed on the inner magnetic core, the outer sense core, or both, in a magnetically balanced configuration relative to a magnetic neutral axis of the inner magnetic core.

Abstract: Certain embodiments of the invention may include systems and methods for determining electrical faults. According to an example embodiment of the invention, a method is provided for determining electrical faults. One method can include providing switch circuitry including at least one first switch detector resistor in parallel communication with at least one switch; providing terminal board circuitry including at least one terminal board resistor in parallel communication with the switch circuitry and in communication with a power source; receiving a power source reference; comparing a field voltage value to a generated reference voltage value, generating a comparison value output based at least in part on the comparison of the field voltage value and the generated reference voltage; and determining one of a plurality of field conditions based at least in part on the comparison value output.

Abstract: Methods for determining a ground fault or insulation degradation condition within energy conversion systems are described. A method for determining a ground fault within an energy conversion system may include, in part, a comparison of baseline waveform of differential current to a waveform of differential current during operation for a plurality of DC current carrying conductors in an energy conversion system. A method for determining insulation degradation within an energy conversion system may include, in part, a comparison of baseline frequency spectra of differential current to a frequency spectra of differential current transient at start-up for a plurality of DC current carrying conductors in an energy conversion system. In one embodiment, the energy conversion system may be a photovoltaic system.

Abstract: An apparatus and method for protecting a power system comprising a generator providing power to an alternating current bus, a power converter for converting alternating current power on the alternating current bus to direct current power on a direct current bus, and a direct current load powered by the direct current power on the direct current bus. An undesired condition is identified at the input to the power converter from the alternating current bus. The undesired condition is caused by at least one of the power converter, the direct current bus, or the load. The power converter is disconnected from the alternating current bus in response to identifying the undesired condition for at least a time delay. The time delay is selected such that the power converter is disconnected from the alternating current bus before the alternating current bus is disconnected from the generator due to the undesired condition.

Abstract: Systems, methods, and circuits are disclosed for detecting continuity of a fuse or other current protection device in a circuit. For example, a signal is generated and coupled onto a closed circuit in which the continuity of the fuse closes the circuit. The signal is then coupled from the closed circuit to a signal detector, which detects the presence of the signal and provides an output indicative of the presence of the signal. If the fuse blows, the circuit is opened, prohibiting the signal from being coupled to the signal detector, in which case the signal detector provides an output indicative of the absence of the signal. This example, however, are not exhaustive.

Abstract: A ground fault detection system may include a direct current (DC) voltage source and an alternating current (AC) device. The ground fault detection system may also include an inverter, coupled to the DC voltage source, the AC device and an electrical ground, including: a positive rail, a negative rail and a plurality of switch elements, wherein each of the plurality of switch elements may be coupled to the positive rail, the negative rail and the AC device. The ground fault detection system may further include a voltage monitoring device coupled to the positive rail, the negative rail and the electrical ground and an electronic controller, coupled to the inverter and the voltage monitoring device configured to: control the plurality of switching elements, sample a voltage potential across the voltage monitoring device at predetermined time periods and determine a ground fault of the inverter based at least in part on the sampled voltage potential and the predetermined time periods.

Abstract: Certain embodiments of the invention may include systems and methods for determining electrical ground faults. According to an example embodiment of the invention, a method is provided determining ground leakage electrical faults. The method includes providing a voltage source having a positive lead in communication with a first contact conductor and a negative lead in communication with a second field conductor, wherein the first contact conductor is connected to a ground through a first resistor Rp, and wherein the second field conductor is connected to the ground through a second resistor Rn; monitoring a first voltage potential associated with the first contact conductor; and determining a condition associated with the first contact conductor, based at least in part on the monitored first voltage potential.

Abstract: The invention relates to a method and a device for determining a maximum leakage current in unearthed power supply networks with a plurality of conductors. The method comprises the steps of: feeding of a measurement signal UP with a measurement frequency fPuls into a conductor arrangement, setting the measurement frequency fPuls, measuring a line-to-line voltage UL-E for each conductor, determining a maximum occurring line-to-line voltage UL-Emax from the measured line-to-line voltages UL-E, determining a voltage UZe across a measurement resistance RM for calculating a leakage impedance ZE, calculating the leakage impedance ZE, and calculating a maximum leakage current THC. The device comprises a signal generator for feeding in the UP with the fPuls, a network coupling circuit between the signal generator and the conductor arrangement, a voltage measuring circuit for measuring the UL-E, and an impedance measuring circuit for determining the Ze by means of the determining of the UZe.

Abstract: Disclosed are abnormality detecting apparatus and method for a high-voltage circuit (A), in which: a square wave pulse is outputted to a measuring point (p1) with a switch (SW1) set off, the switch (SW1) provided between an inverter circuit (2) and the ground, a difference voltage (Vp-p) between a voltage (Vh) detected at a phase of T/2 and a voltage (V1) detected at a phase of T is obtained, the occurrence of a ground fault is detected based on the size of the difference voltage (Vp-p); and the square wave pulse is outputted to the measuring point (p1) with the switch (SW1) set on, and it is judged that a loosening of a fastening section (p2) occurs when the difference voltage (Vp-p) exceeds a reference voltage (Vref2).

Abstract: A ground fault detection circuit may include a switch circuit that connects or disconnects a path between a bus bar connected to a secondary battery and a ground potential section; an I/V conversion resistance element for detecting a ground fault of the bus bar based on an electric current flowing through the path; and a resistance element connected in series to the I/V conversion resistance element.

Abstract: Apparatus and methods for detection of a ground fault on a DC side as well as on an AC side of an inverter are presented. A detection means can receive forward and reverse current and provide an induced current based on the difference between them. A parameter associated with the induced current, or a parameter associated with a voltage generated by conduction of the induced current through a device, can be used to detect a ground fault. In addition, a detection means can be configured to receive transient current, and a resulting voltage at the detection means can be used for fault detection. A detection means can be disposed at the DC side of an inverter or at the AC side of the inverter. Apparatus and methods can be configured to detect AC leakage current caused by a ground fault.

Abstract: A connector includes a first terminal to which a power supply is connected, the power supply being a direct current power supply, a second terminal to which a signal ground of the direct current power supply is connected, and a third terminal connected to a frame ground, the third terminal being arranged at a location between the first terminal and the second terminal.

Abstract: A method and an apparatus for detecting a phase-to-earth fault on a three-phase electric line of an electric network, the apparatus determining a neutral admittance based on a ratio of a difference between zero sequence currents on the three-phase electric line and a difference between zero sequence voltages in the electric network before an earth fault and during the earth fault. The apparatus also compares the determined neutral admittance, to a predetermined operation characteristic to detect a phase-to-earth fault on the three-phase electric line. The predetermined operation characteristic, when presented on an admittance plane, defines a closed area such that the center of the closed area is offset from the origin of the admittance plane towards a negative susceptance direction and/or towards a negative conductance direction.

Abstract: There is here disclosed a method and apparatus for detecting the occurrence of arcing of a conductor by monitoring the current on an AC power line. The signal detected is split and directed along four separate paths to generate four signals having separate characteristics which represent the current in the line. Upon the detection of arcing, an output signal can be generated to activate a circuit interrupting mechanism, sound an audio alarm and/or alert a central monitoring station.

Abstract: Systems, methods and devices which utilize Spread Spectrum Time Domain Reflectometry (SSTDR) techniques to measure degradation of electronic components are provided. Such measurements may be implemented while the components “live” or otherwise functioning within an overall system. In one embodiment, monitoring a power converter in a high power system is accomplished. In this embodiment, degradation of components within the power converter (e.g. metal-oxide-semiconductor field-effect transistors (MOSFETs), capacitors, insulated-gate bipolar transistors (IGBTs), and the like) may be monitored by processing data from reflections of an SSTDR signal to determine changes in impedance, capacitance, or any other changes that may be characteristic of components degrading. For example, an aging MOSFET may experience an increase of drain to source resistance which adds additional resistance to a current path within a power converter.

Abstract: A method is provided for detection of a ground fault in a high resistance network in a voltage source power conversion circuit comprising a power converter that converts incoming AC power to DC power applied to a DC bus and an inverter that converts DC power from the DC bus to output AC power. The method includes detecting a midpoint-to-ground voltage between a low side of the DC bus and a ground potential and detecting the presence of a ground fault in a high resistance network based upon the detected midpoint-to-ground voltage.

Abstract: In monitoring an isolation of an ungrounded power grid an AC voltage source is connected to the power grid via at least one test resistor. A test signal with a periodic continuous voltage course with regard to ground and with a frequency is applied to the power grid by means of the AC voltage source. A leakage current flowing due to the test signal is measured; and an ohmic isolation resistance is determined from the leakage current. The frequency of the test signal is varied such that an active current part of the leakage current keeps a predetermined recommended value at varying leakage capacitances of the power grid. This provides for a desired level of accuracy at maximum speed of isolation or ground fault detection.

Abstract: A system and method for non-intrusive fault detection of a ground fault in a communication channel is provided. A bias voltage may be established on a first portion of the communication channel and a second portion of the communication channel. A first voltage may be detected across a first resistor electrically connected to the first and second portions of the communication channel. Data indicative of whether the ground fault exists in the first or second portions of the communication channel may be provided based on the detecting.

Abstract: Techniques are presented for determining current levels based on the behavior of a charge pump system while driving a load under regulation. While driving the load under regulation, the number of pump clocks during a set interval is counted. This can be compared to a reference that can be obtained, for example, from the numbers of cycles needed to drive a known load current over an interval of the duration. By comparing the counts, the amount of current being drawn by the load can be determined. This technique can be applied to determining leakage from circuit elements, such as word lines in a non-volatile memory.

Abstract: A method, system and computer program product are disclosed for identifying false positive indications of high impedance faults in an AC electric power transmission and distribution network. In one embodiment, the method comprises using a procedure to monitor a phase conductor of the network for faults, said procedure generating a fault signal indicating a specified fault in the conductor. In this embodiment, the voltage and current waveform of the electric power conducted through the conductor are monitored. When a phase shift in said waveform is detected over a defined period of time, and said detected phase shift meets one or more given criteria, a correction signal is generated indicating that said fault signal is a false indication of the specified fault. The given criteria may include, for example, that the phase shift is more than a threshold value for a specified period of time.