Abstract: A detecting station of a winding product and a method for detecting an inter-turn short circuit are provided. The method includes following steps. First, a high voltage pulse is input to two ends of a winding of a winding product. Next, a voltage value of an electrifying process of the winding is extracted for generating an extracting data. Finally, a time-frequency converting operation is performed to the extracting data, and a time-frequency analysis information is generated for indicating whether or not the inter-turn short circuit is occurred in the winding.

Abstract: A ground fault detection system is provided. The ground fault detection system includes a magnetic core having first and second primary legs and a secondary leg disposed between the first and second primary legs. The ground fault detection system also includes first and second primary windings disposed around the first and second primary legs respectively and configured to introduce current in the first and second primary legs. Further, the ground fault detection system includes first and second secondary windings disposed around the first and second primary legs respectively and configured to detect a ground fault based upon a magnetic flux generated in response to the introduced current.

Abstract: Embodiments of methods and apparatuses for characterizing an electrical power distribution system are disclosed. One method includes applying at least one test signal to at least one test point of the system, measuring a plurality of response signals at a plurality of test points, wherein the plurality of response signals are generated in response to the at least one test signal, and characterizing the system based on the plurality of response signals. One system includes a plurality of test/response units attached to a plurality of test points, the units configured to generate test signals and/or measure response signals at the test points. At least one controller coordinates application of the test signals and characterizes the electrical network based on the response signals. A communications link allows the test/response units to communicate with the at least one controller.

Abstract: A testing apparatus for testing a welding apparatus is disclosed. The testing apparatus includes a receptacle, a fault indicator, and a power supply. The receptacle includes a grounding socket and a plurality of power sockets. The power supply is electrically coupled to the grounding socket, the fault indicator, and at least one of the plurality of power sockets. When a plug of the welding apparatus is matingly coupled to the receptacle, the fault indicator indicates whether an electrical resistance between a grounding prong of the plug and at least one of a plurality of power prongs of the plug is below a predetermined threshold.

Abstract: The invention relates to a method and an apparatus for determining an actual insulation resistance RISO in IT systems grounded with a functional grounding resistance RHRG, comprising constant insulation monitoring. In one embodiment of the invention, the functional grounding resistance RHRG is determined during the initial inspection of the IT system, determining a total insulation resistance Rges is carried out during the constant insulation monitoring, and the actual insulation resistance RISO is determined during the operation of the IT system from the functional grounding resistance RHRG and the total insulation resistance Rges.

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 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 method and device for insulation fault monitoring in ungrounded electrical networks. The method includes the following steps: measuring an insulation resistance, determining a responding value for the insulation resistance, and triggering a warning signal if the measured insulation resistance falls below the responding value, wherein the responding value is determined dynamically as a momentary responding value in a warning value establishment process downstream of the insulation resistance measurement.

Abstract: An electronic trip device is described that includes a test signal generator coupled to at least one of a line conductor and a neutral conductor and configured to create a test signal. The electronic trip device also includes a leakage current detection circuit configured to compare a current in the line conductor and a current in the neutral conductor, the leakage current detection circuit configured to output an error signal if the test signal is not detected.

Abstract: An electric leakage sensing apparatus includes a coupling capacitor having one end connected to a DC power supply, a pulse generator that supplies a pulse to the other end of the coupling capacitor, a voltage detector that detects a voltage at the coupling capacitor charged by the pulse, an electric leakage determination part that compares the voltage detected by the voltage detector to a threshold value, and makes a determination of existence or non-existence of an electric leakage of the DC power supply based on a comparison result, and a booster circuit that applies a boosted pulse voltage to the coupling capacitor. The pulse generator converts an output voltage of the booster circuit into the pulse voltage. The voltage detector includes an offset voltage generating circuit that generates an offset voltage.

Abstract: A leakage detector is provided with the addition of an output control circuit that monitors a circuit wire-to-ground voltage, which is at the root of a suffered operation and produced between a transformer B-class grounding phase of a monitored circuit and a D or C-class grounding electrode or a ground structure etc. of an electrical equipment connected to the grounding electrode, execute a phase judgment of a leakage current detected by a zero-phase current transformer on the basis of the monitored voltage, and stop an output operation of the leakage detector when the leakage current is a suffered current flowing from a load side L of the detecting zero-phase current transformer toward the power side K, i.e. the transformer and when the circuit wire-to-ground voltage exceeds an appropriately-established dynamic sensitivity voltage value.

Abstract: A method and circuit 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: A testing device which may be used to conduct ground resistance and soil resistivity measurements. The testing device comprises both a main unit and a remote unit adapted to communicate with one another via a communication link. After setting the testing device up according to the desired measurement technique, the procedure may be carried out, and the resulting measurement values are subsequently displayed on the remote unit. This allows a single operator to perform measurements while standing directly adjacent to an electrode, which is, for example, placed at a large distance from the main unit and/or other electrodes. This relieves the operator from constantly having to walk back and forth placing electrodes in different positions, and also obviates the need to return to the main unit of the testing device to consult a display and/or change parameters or settings.

Abstract: A method for determining an adjustment value for an electrical protection device wherein, upon occurrence of a ground short circuit, first current indicator measured values and first voltage indicator measured values are captured by a first measurement device at a first end of a segment of an electrical power supply line, and second current indicator measured values and second voltage indicator measured values are captured by a second measurement device at a second end of the segment of an electrical power supply line. In order to design a method of this type such that an adjustment value for a ground impedance can be determined in a relatively simple fashion.

Abstract: Presented are circuits and methods for providing real-time short-circuit detection, capable of detecting a short-circuit prior to occurrence of an over-limit current event. Such a circuit can be used to provide real-time short-circuit detection for a switched-mode system for a switched-mode system having a pre-driver and a power stage, and includes a reference block for generating a reference voltage according to drive signals provided by the pre-driver, and a comparator, which may be a synchronized comparator. The comparator is configured to compare the reference voltage to a switching node voltage generated in a power stage of the switched-mode system, and to produce an output enabling detection of the short-circuit in the switched-mode system.

Abstract: Methods and apparatus for continuous ground fault self-test are disclosed. An example ground fault detection device includes a sense coil to detect current in a line conductor and a neutral conductor, the sense coil comprising a winding influenced by a current difference between the line conductor and the neutral conductor. The example ground fault detection device also includes a current bypass to facilitate a continuous current imbalance detected by the sense coil, and a ground fault detector circuit to detect at least one of the continuous current imbalance in the sense coil or a ground fault current imbalance.

Abstract: A method and an apparatus for detecting an earth fault on a three-phase electric line are provided. The apparatus includes means for determining a neutral admittance on the basis of a residual current and a residual voltage, means for comparing the determined neutral admittance to a predetermined operation characteristic to detect an earth fault on the three-phase electric line, and means for determining one or more harmonic components of the residual current and one or more harmonic components of the residual voltage. The harmonic components have frequencies n*fn such that n?2 and fn is a fundamental frequency. The means for determining a neutral admittance are configured to use at least one of the determined one or more harmonic components of the residual current and at least one of the determined one or more harmonic components of the residual voltage for determining the neutral admittance.

Abstract: For the purpose of determining a fault current component of a differential current which is measured as a current sum over a plurality of lines carrying a current of an AC current generator, an electric signal which depends on generator voltages present at the AC current generator with respect to earth potential and which is in phase with a leakage current component of the differential current is generated. The electric signal is scaled by multiplying it by a scaling factor; and the scaled electric signal is subtracted from the differential current to obtain a remainder. The scaling factor is repeatedly updated such that the effective value of the remainder reaches a minimum at the present value of the scaling factor.

Abstract: Embodiments relate to fault detection comparator circuitry and methods that can operate in conjunction with a power-on-reset (POR) scheme to put a chip into a reliable power-down mode upon fault detection to avoid disrupting the communication bus link such that other connected chips and the host can continue to operate. Power-on of the affected chip can then be carried out when the connection with that chip is restored.

Abstract: A ground fault detection system detects an earth fault or ground fault in a network device. The network device may be used in a fire alarm network. The ground fault detection system includes a power device that electrically isolates the ground fault detection system. A controller sequences a series of switches or relays to charge an energy storing element, such as a capacitor, with the isolated power supply. The capacitor is placed in communication with each port of the network device one at a time. If the connected port includes an inadvertent connection to ground, a detection circuit will detect the bias on the earth ground. The detection circuit may then output an indication of the inadvertent connection to ground to either a workstation or a fire alarm control panel.

Abstract: A capacitor capacitance diagnosis device includes a power supply which is for charging a capacitor, a discharge circuit which is connected to the capacitor in parallel to discharge energy of the capacitor, a resistance dividing circuit which is for measuring voltage drop value during discharging, a measurement circuit which measures divided voltage, and a diagnosis circuit which determines adequacy of capacitor capacitance from a time change in voltage due to the discharge. This makes it possible to diagnose adequacy of capacitor capacitance of an electric power apparatus during operation.

Abstract: An electrical connection defect detection system to detect whether an electrical connection between an under-test pin of an under-test device and a signal line of a circuit board is normal is provided. The electrical connection defect detection system comprises a signal provider providing a test signal to the under-test pin through the signal line, a detection module, an electrode board and a plurality of grounding paths. The electrode board comprises a detection surface to be adapted to a surface of the under-test device opposite to the under-test pin to make the detection module detect a capacitance value associated with the electrode board, the under-test pin and the signal line larger than a threshold value when their connection is normal. The grounding paths are connected to one of not-under-test pin groups respectively to further connect to the ground potential. An electrical connection defect detection method is disclosed herein as well.

Abstract: This invention relates to a method and apparatus of detecting and compensating for DC residual fault currents on electrical systems. In particular, the present invention relates to a method and apparatus which is capable of accurately detecting one or more parameters of the fault current waveform and generating a compensation factor which compensates for specific pulsed DC fault components present. In this way, trip sensitivity is optimized for all types of fault current waveforms. In a preferred embodiment, the present invention operates by detecting one or more parameters of the encoded fault current waveform and generating a measure of symmetry comparing the mean squared values of negative and positive sections of said encoded fault current waveform. In use, various bands of the ratio of the mean squared sum of the positive and negative sections of said encoded fault current waveform are obtained, and a compensation factor is determined from a look-up table stored in a processing means.

Abstract: An apparatus and method for protecting against electrocution hazards that arise when an appliance is electrically connected to a miswired single-phase AC electrical source which includes an energized ground lead are described. The apparatus includes one or more sensors that detect electrical energy in the ground lead combined with a miswiring condition in the hot and common leads. A tester embodiment is also illustrated. The method includes the steps of detecting if the putative ground of the electrical source is energized and whether the hot and common leads are reversed.

Abstract: An automatic fault detector momentarily interrupts a provision of operating power to a load having a minimal forward-bias voltage requirement to thereby provide a testing window and then applies a test voltage during this window that is less than the minimal forward-bias voltage requirement to the load and monitors for a power-to-ground fault. By one approach the aforementioned momentarily interruption of power is neither frequent enough nor long enough in duration to substantially impair the provision of power to the load. Accordingly, load performance is not noticeably diminished. One can then responsively prohibit subsequent provision of the operating power to the load. One can then continue to monitor for the power-to-ground fault while continuing to prohibit provision of operating power to the load. If and when the fault disappears, these teachings will then accommodate automatically resuming an ordinary provision of power to the load.

Abstract: An electric leakage sensing apparatus includes a pulse generator that supplies a pulse to a coupling capacitor, a voltage detector that detects a voltage at the coupling capacitor, an electric leakage determination unit that compares the voltage detected by the voltage detector to a threshold and determines existence or non-existence of an electric leakage of a DC power supply based on a comparison result, a pre-check circuit that puts the DC power supply into a pseudo electric leakage state, a diagnostic unit that diagnoses whether the electric leakage determination unit determines that the electric leakage exists when the DC power supply is put into the pseudo electric leakage state, and terminals to which cables are connected. A current route from the pulse generator to the pre-check circuit through the coupling capacitor and the cables is formed when the DC power supply is put into the pseudo electric leakage state.

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: Certain embodiments of the invention may include systems, methods for providing determining electrical faults. According to an example embodiment of the invention, a method is provide 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: A three-phase faulted circuit indicator adjustable to accommodate a variety of three-phase power cables is disclosed. In one embodiment, faulted circuit indicator comprises a flexible holder that encircles the monitored conductor slightly more than one time. The flexible holder includes a plurality of magnetic sensors for monitoring the current within the internal conductors of the power cable, a logic circuit for determining the occurrence of a fault, and an output device for providing an indication of a fault. In a second embodiment, the faulted circuit indicator comprises a plurality of sensor compartments, each disposed about a central point, and each coupled to two other sensor compartments.

Abstract: An inverter application comprises at least one apparatus fed by an inverter (10). The determining of insulation defects is effected by way of a differential voltage of part voltages (U, U?) of an intermediate circuit (7) or the ratio of one of these part voltages (U, U?) to the total voltage of an intermediate circuit, and by way of an operating condition of the inverter (10). The monitoring of the insulation is carried out only with the means (1a, 1b, 1c, 1a?, 1b?, 1c?, 5, 5?) which are present in the inverter (10) in any case. The operating condition is set as a particular switch position in the inverter (10) by an insulation monitoring system. Alternatively, the operating condition is, while the inverter is on-line or in operation, transferred from the inverter control (9) to an insulation monitoring system for improving the quality of the monitoring.

Abstract: Methods and apparatus to minimize saturation in a ground fault detection device are disclosed. An example method includes connecting a capacitor simulator to a node of the ground fault detector device to prevent saturation, and monitoring power-line conductors for ground fault conditions with the ground fault detector device. An example apparatus to simulate a saturation capacitance in a ground fault device includes a sense coil induced by power-line conductors, and at least one of an amplifier or a current detector including an input connected to the sense coil and an output connected to a ground fault detector. The example apparatus also includes a saturation capacitor simulator connected to a node of at least one of the amplifier or the current detector to prevent saturation.

Abstract: An insulating state detection unit is configured to perform failure detection for switches, which connect a flying capacitor to a sample hold circuit for acquiring a charge voltage and a ground potential, by using a failure determination threshold value according to a variable value. That is to say, the insulating state detection unit is configured to decide the failure determination threshold value by taking, as a reference, a charge voltage of a capacitor of the sample hold circuit charged with electric charge amount corresponding to a charge voltage of the flying capacitor when the flying capacitor is charged with electric charge amount corresponding to an output voltage of a DC power supply.

Abstract: The invention relates to an arrangement (10) for ground fault monitoring of an AC circuit between, on one hand, a neutral conductor (N?) of the AC circuit and, on the other hand, a protective ground wire (PE) or a ground wire with a series connection of ohmic resistors (R1, R2, R3), which has a first terminal (101) for the neutral conductor (N?) and a second terminal (102) for the protective ground wire (PE) or ground wire, wherein the arrangement includes at least one means for detecting a break of one of the resistors (R1, R2, R3) of the series connection.

Abstract: The present application describes, among other things, a ground fault detection system. The system includes an optocoupler, a current sink, and a first voltage source connected in series. The first voltage source can connect to a negative terminal of a battery unit. Upon connection between a positive terminal of the battery unit and a first node at a ground zero reference level, current can flow through the optocoupler and the current sink to cause the optocoupler to output a ground fault detection signal.

Abstract: One embodiment relates to a fault circuit interrupter comprising at least one grounded neutral sensor and at least one test circuit configured to test the grounded neutral sensor. A further embodiment can also include at least one fault circuit which is configured to detect a current sent from the grounded neutral sensor. The device can also include a line side phase line, a line side neutral line, and a test line coupled to the line side neutral line and extending from a first region on the line side neutral line to a second region on the line side neutral line, with the grounded neutral sensor being positioned between the first region and the second region on the line side neutral line. This test circuit can comprise a switch, such as a manually operatable switch or it can comprise any one of solid state circuitry, a transistor, and/or a silicon controlled rectifier. The device can also include a differential sensor and at least one second test circuit configured to directly test differential sensor.

Abstract: A method, apparatus and computer program for detecting an AC chassis fault on one or more DC/AC converters having a load is disclosed, including receiving a chassis voltage VChassis signal from between DC link and a chassis ground from the DC/AC converter, capturing a side band harmonic of the chassis voltage VChassis signal, determining a peak magnitude value related to the side band harmonic, comparing the peak magnitude value to a predetermined threshold value, wherein if said peak magnitude value equals or exceeds the predetermined threshold value, an AC chassis fault condition is detected.

Abstract: A circuit breaker for protecting a power line. The circuit breaker includes a control unit and a circuit breaking element disconnecting the power line from a power source. The control unit detects a fault on the power line, opens the circuit breaking element, which opening starts a disconnection time interval, injects a test signal into the power line, measures a response, determines an impedance of the power line from the response, analyses the impedance during the time interval based on comparing the impedance with a reference threshold, determines a permanent or a temporary fault based on the analysed impedance, re-closes the circuit breaking element after the time interval if the fault is temporary and keeps the circuit breaking element open after the time interval if the fault is permanent.

Abstract: A method for detecting a ground fault in an electrical supply system includes using a combination of components and their connections within the supply system to form virtual components, allowing presetting of fault indicators for incoming and outgoing supply lines to individual components. A fault index can be determined for each virtual component in conjunction with a respective association of a correlation coefficient with fault indicators and a subsequent normalization over all fault indicators using a correlation coefficient. Comparison of the indices of all virtual components of the supply system permits a determination of that virtual component in which the highest fault index occurs, and therefore in which there is the highest probability of a fault. The fault search in a supply system can therefore be determined quickly and easily independently of power supply system geometry and configuration. An apparatus performing the method and computer program product, are also provided.

Abstract: A faulted circuit indicator (FCI) for providing an indication of a fault on a monitored conductor, determining whether the FCI is near the end of its useful life (or entered into an end-of-life mode) and altering an operation of the FCI if the useful life of the FCI has reached a select threshold. The operation alteration may include an alteration of the display and/or deactivation of certain features and/or functions of the FCI. Thus, the useful life of the FCI will be increased. Further, utility personnel will be more likely to notice that the FCI is in end-of-life mode. The FCI may also include a battery discharge module and a thyristor for discharging the battery for disposal upon decommissioning of the FCI.

Abstract: A fault detector for use with a telephone wire-pair having a return conductor and an output conductor, a method of protecting a telecommunications network including the telephone wire-pair and a power supply for the telecommunications network. In one embodiment, the fault detector includes (1) a passive sensor coupled between Earth and the wire-pair to detect a ground fault thereon, (2) an amplifier having inputs coupled across the passive sensor and configured to characterize the ground fault in terms of a value and (3) a controller configured to receive the value via an output of the amplifier and compare the value to a threshold to determine if the ground fault exceeds a safety limit.

Abstract: An electric vehicle incorporates a ground fault detecting system and has first and second ungrounded power supplies. The ground fault detecting system includes a first insulation resistance detector for detecting a first insulation resistance of the first ungrounded power supply with respect to a grounded region of the electric vehicle, and a second insulation resistance detector for detecting a second insulation resistance of the second ungrounded power supply with respect to the grounded region. The first insulation resistance detector and the second insulation resistance detector detect the first insulation resistance and the second insulation resistance at different times, respectively.

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: The invention relates to a ground distance protection method, which comprises: measure local source impedance based on fault component at both ends (M, N) of the transmission line in the case of a ground distance fault has occurred. Send the measured local source impedance from a first end to a second end. Adjust a protection criterion at the second end based on the measured impedance. And, judge the ground fault as an internal fault or an external fault according to the adjusted protection criterion. The invention also relates to a controller, a piece of software and an apparatus for implementing the same function.

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: This invention relates to a time alert device (1) for use with an earth leakage protection device comprising a microprocessor system (10) provided with a software controlled alert trigger timer (22). On time out of the alert trigger timer, the microprocessor system (10) initiates an audible and/or visual annunciation to remind the user of the earth leakage protection device to perform integrity test on the earth leakage protection device. If the earth leakage protection device fails the integrity test, the user detects that the earth leakage protection device could be faulty and needs expert attention. If the earth leakage device passes the integrity test, the alert trigger timer is reset for another predetermined time interval to remind the user to perform another integrity test on the earth leakage protection device. The time alert device can be further provided with a message display panel.

Abstract: An insulation state detector detects an insulation state with respect to a ground potential portion of a DC power source on the basis of a charging voltage of a flying capacitor. The insulation state connector includes a detecting section that detects the insulation state of the DC power source by defining the charging voltage of the flying capacitor in the ground fault state as a charging voltage, in an unbalanced state where voltages across both ends of the positive-side Y capacitor and the negative-side Y capacitor are not equal to voltages obtained by dividing the voltage of the DC power source according to a voltage division ratio of the positive-side ground fault resistor and the negative-side ground fault resistor.

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: When line break detection of signal line Ln is carried out, potential smaller than signal line Ln?1 having lower potential than signal line Ln is supplied to signal line Ln, and potentials of signal line Ln and signal line Ln?1 are compared. If potential of signal line Lc>signal line Li, it is detected no line break, and if signal line Lc<signal line Li, it is detected that a line break exists. Then, potential larger than signal line Ln+1 having higher potential than signal line Ln is supplied to signal line Ln, and potentials of the signal line Ln and signal line Ln+1 are compared. If potential of signal line Lc<signal line Li, it is detected no line break, and if signal line Lc>signal line Li, it is detected that a line break exists.

Abstract: The invention is a simple amplifier circuit for a current transformer to measure very small AC currents, as required for ground fault detection. The circuit presents a very low impedance to the current transformer output and provides high amplification of the current transformer signal. Concurrently and with no additional components, the inventive circuit supplies a bias current to the current transformer to improve its performance and provides output signals which can be used to detect disconnection of the current transformer or a short circuit between either of the current transformer terminals and ground.

Abstract: Disclosed are apparatus and methodologies for providing improved functionality of a meter in a 2-way communications arrangement, such as an Advanced Metering System (AMS) or Infrastructure (AMI). More particularly, the present technology relates to methodologies and apparatus for providing load side voltage sensing for utility meters which preferably are operable with remote disconnect features in an Advanced Metering Infrastructure (AMI) open operational framework. The present subject matter provides enhanced capabilities resulting in improved functionality, increased safety, and greater economy vis-à-vis fraud detection for individual metrology components in an open operational framework. Meters per the present subject matter utilize a detection circuit, which is situated generally downstream of a remote disconnect functionality. Such detection circuit is able to sense whether voltage exists or doesn't exist at such relatively downstream, or load side location.