A contact test device for a hi-pot test includes: a contact test device connected to a hi-pot test device in parallel by lines branched from first and second lines of the hi-pot test device by being connected to first and second terminals of a battery through first and second probes, respectively, and having third and fourth probes directly connected to the first and second terminals, wherein the contact test device includes: a first closed loop including first to third switch units, a direct current (DC) voltage source and a first continuity detection unit; a second closed loop including fourth to sixth switch units, the DC voltage source and a second continuity detection unit; and a control unit controlling turning the first to sixth switch units on and off and detecting a continuity signal of each of the first and second continuity detection units.

A method and a system for fault verification of an electronic device are provided. The electronic device includes a device to-be-verified. The method includes the following. A first power-supply voltage is applied to the electronic device until the device to-be-verified satisfies a material-failure condition. A second power-supply voltage is applied to the electronic device to determine whether the electronic device has safety risk. The first power-supply voltage is higher than the second power-supply voltage, and the safety risk is caused by material failure in the device to-be-verified. The method and the system for fault verification of an electronic device can verify safety risk caused by material failure in internal components of the electronic device.

An apparatus for locating partial discharges in a medium-voltage or high-voltage operating equipment comprises a signal detection device for detecting an electrical signal variable of the operating equipment, a filter device for low-pass filtering of the detected electrical signal variable dependent upon a filter cut-off frequency, a time detection device for detecting a signal propagation time of the low-pass-filtered electrical signal variable, and a comparison device for comparing the detected signal propagation time detected dependent upon the filter cut-off frequency with a reference propagation time for a charge pulse conducted through the operating equipment in order to determine a location of the partial discharge in the operating equipment dependent upon the result of the comparison. Also provided is a method for locating a partial discharge in medium-voltage or high-voltage operating equipment, in particular, using the apparatus.

An apparatus and method for identifying liner holidays, with a generator having two contacts with a liner and pulsing current to a moving one of the contacts. A plurality of detected electric signals are processed to continuously generate a baseline indicative of a holiday. A holiday signal is actuated when a signal is detected which when compared to the generated baseline indicates a holiday. A plurality of electric signal types and baselines, such as current strength and voltage, may be separately detected with a holiday signal actuated when either signal type is detected which when compared to its generated baseline indicates a holiday. The moving contact may be flexible to conform to contour of the liner.

An earth fault detection apparatus includes a switch group configured to switch between a first measurement path including a battery and a capacitor, and a second and third measurement paths including the battery, a positive/negative-side insulation resistance, and the capacitor; a reference resistance and a test switch; and a control unit calculating a first reference value based on each charging voltage in a case where the test switch is opened and the capacitor is charged, and calculating the insulation resistance with reference to a conversion map created to correspond to an electrostatic capacitance between a power supply line and ground, wherein the control unit calculates a second reference value based on each charging voltage in a case where the test switch is closed and the capacitor is charged for a shorter time, and estimates the electrostatic capacitance with reference to a predetermined test conversion map.

Provided are a live detection method and apparatus for a high-voltage switch cabinet. The live detection apparatus for a high-voltage switch cabinet includes a robot body and a back-end server. The robot body includes a host module, a power module, a detection module and a motion module. The power module is electrically connected to the host module and the motion module. The host module is communicably connected to the motion module and the detection module. The detection module includes a visible light camera, an infrared thermal imager, an non-contacting ultrasonic sensor and an ultrahigh-frequency sensor. The motion module includes a horizontal motion module, a vertical motion module and a rotating motion module. The horizontal motion module includes a motor-driven carrier and a laser navigation system. The vertical motion module is secured to the motor-driven carrier.

The invention relates to a method and a photovoltaic inverter (2) for determining the insulation resistance (R.sub.iso) of a photovoltaic system (1) relative to ground (PE). According to the invention, the voltage required for the measurement can be provided by the intermediate circuit (6) in the form of the intermediate circuit voltage (U.sub.Zk), and the measuring device (13) is designed to actuate an input short-circuit switch (S.sub.Boost) for short-circuiting the DC input (3) with the AC disconnector (8) open, as a result of which the intermediate circuit voltage (U.sub.Zk) can be applied to the DC input (3) in the reverse direction, and the measuring device (13) is configured to record measured voltages (U.sub.M1, U.sub.M2) with the switch (S.sub.iso) of the voltage divider (14) open and closed, and to determine the insulation resistance (R.sub.iso) from the measured values of the two measured voltages (U.sub.M1, U.sub.M2) recorded with the switch (S.sub.iso) of the voltage divider (14) open and closed.

A system to enable identification of arcing hazards comprises a data storage to store a set of measurements acquired by measurement units of a power distribution system. The system further comprises at least one processor configured to identify candidate arcing events represented by the measurements by using an unsupervised machine learning process, and to train a supervised machine learning classifier for automatic real-time identification of arcing events, by using labeled training data based on the identified candidate arcing events.

An arc-like radio frequency (RF) noise detector device is configured to detect and display RF noise on a residential circuit branch that cause or contribute to an arc fault circuit interrupter (AFCI) circuit breaker tripping. It includes a power cord with a plug to connect to a receptacle on a branch circuit of the AFCI circuit breaker to detect RF noise. It further includes a RF noise coupling circuit to receive power from a power entry module and coupled to an Application Specific Integrated Circuit (ASIC) to generate a Received Signal Strength Indicator (RSSI) signal from the detected RF noise. It further includes a power supply, a signal display device configured to receive and display the RSSI signal on a display screen to determine nature of a breaker trip event or likelihood of the breaker trip event and a battery to power the signal display device.

The disclosure describes a method for detecting an arc in a direct-current (DC) circuit comprising a DC load, a DC source supplying the DC load, and a circuit arrangement arranged between the DC source and the DC load. A power flow P between an input and an output of the circuit arrangement is suppressed by means of a switching circuit through cyclical interruption such that the power flow P is enabled in an active time window with the first period Δt.sub.1 and the power flow P is suppressed in an inactive time window with the second period Δt.sub.2. Via detection of an input current I.sub.in flowing at the input and/or an input voltage U.sub.in applied to the input and comparison of values of the input current I.sub.in and/or input voltage U.sub.in detected in the inactive time window with a current threshold value I.sub.TH or a voltage threshold value U.sub.TH an arc presence criterion is signaled if the input current I.sub.in detected in the inactive time window falls below the current threshold value I.sub.TH and/or the input voltage U.sub.in detected in the inactive time window does not exceed the voltage threshold value U.sub.TH. The application also describes a circuit arrangement for detecting an arc and a photovoltaic (PV) inverter including such a circuit arrangement.