The disclosure discloses a method and device for detecting insulation state in a conversion system, wherein the conversion system includes an excitation source, a converter having an input end coupled to the excitation source, a connection element coupled between an output end of the converter and a reference point, and a coupling impedance having a first end coupled to the excitation source and a second end coupled to the reference point, the method for detecting insulation state including steps of: S1, controlling at least one main power switch of the converter not to switch; S2, detecting a pulse current signal of the connection element; and S3, processing the pulse current signal and outputting a partial discharge information, the partial discharge information indicating an insulation state of an isolating transformer in the converter. The disclosure can overcome electromagnetic interference of high frequency steep waves on a partial discharge signal.

A system for acoustically detecting dielectric breakdown of, or partial discharge within, or on, an electrical device includes at least one electroacoustic (EA) transducer configured to detect an acoustic vibration of the electrical device, and a controller electrically connected to the at least one EA transducer. The controller is configured to receive a signal from the at least one EA transducer, and analyze the signal to determine whether the signal includes data associated with an acoustic vibration in a frequency range of dielectric breakdown and/or partial discharge of the electrical device. The applicability of such a system includes, but is not limited to, electronic parts or assembly screening, life characterization testing for materials and processes, diagnostic methods or aides, augmenting testing of components, assemblies or systems, and in service monitoring to support preventative or condition based maintenance to avert an in-service issues.

A relay diagnosis apparatus includes a first voltage detection circuit to generate first and second diagnosis voltages between positive and negative electrode terminals of a battery assembly and a chassis, respectively; and a controller to determine first and second insulation resistances between the positive and negative electrode terminals and the chassis, respectively, based on the first and second diagnosis voltages at first and second time points while respective relays are controlled into an off-state. The controller determines third and fourth insulation resistances between the positive and negative electrode terminals and the chassis, respectively, based on the first and second diagnosis voltages at third and fourth time points while the first and second relays are controlled into an on-state. The controller detects relay faults based on the insulation resistances.

A fail-safe device is disclosed for ensuring compatibility and reliable operation of a Voltage Indicator System (VIS) for a medium- or high-voltage apparatus in presence of a monitoring system with: a first and second fail-safe device terminal; the first terminal being connectable to an output terminal of a coupler, the coupler being provided in a medium- or high voltage portion of the apparatus, and the second terminal being connectable to an input terminal of the VIS, which is provided in the low-voltage portion; a third and fourth fail-safe device terminal, wherein the third and fourth terminals being electrically connectable to first and second input/output terminals of the monitoring system; and an electrical circuit connecting the first and second fail-safe device terminal and being adapted to compensate for electrical failure modes of the monitoring system such, that the VIS is operable in case the electrical failure modes occur.

A method and a photovoltaic inverter for determining the insulation resistance of a photovoltaic system relative to ground are provided. The voltage required for the measurement can be provided by an intermediate circuit in the form of an intermediate circuit voltage and a measuring device is designed to actuate an input short-circuit switch for short-circuiting a DC input with an AC disconnector open, as a result of which the intermediate circuit voltage can be applied to the DC input in the reverse direction. The measuring device is configured to record measured voltages with a switch of a voltage divider open and closed, and to determine the insulation resistance from the measured values of the two measured voltages recorded with the switch of the voltage divider open and closed.

A method of determining polymerisation of transformer insulation within a transformer. The method includes the steps of measuring a first and second moisture activity of oil in a transformer, and a first and second temperature of the transformer. The method further includes calculating the ratio of the gradients of the moisture equilibrium curves associated with the moisture activity and the temperature. The calculated ratio can then be used to characterise the polymerisation of the insulation and age of the transformer.

A diagnostic test instrument for testing power system equipment may include a chassis having a number of bays capable of receiving test circuitry modules, which may be field inserted by a user desiring to perform a particular test. The instrument may include controller circuitry that may sense in each of the bays whether a respective test circuitry module is inserted therein, and then interrogate respective test circuitry modules in each respective bay to identify a type of the respective test circuitry module. Available testing capabilities may be identified according to the type of each of the respective test circuitry modules identified in respective bays. The controller circuitry may output configuration instructions to test circuitry modules, and respective test ports included in each of the respective test circuitry modules may be selectively illuminated as a configuration instruction to visually identify an assigned functionality of the respective test ports.

A method includes placing a semiconductor device package in a test handler, the semiconductor device package having leads of a first portion of a package substrate extending from a mold compound and leads of a second portion isolated from the first portion extending from the mold compound; contacting the first portion with a first and a second conductive slug; contacting the second portion with a third and a fourth conductive slug; contacting a first surface of the mold compound with a first plunger having a conductive plate and an insulating tip; contacting an opposite second surface of the mold compound with a second plunger having a conductive plate and an insulating tip; and placing a high voltage on the first conductive slug while placing approximately half the high voltage on the conductive plate of the first plunger, and placing a ground voltage on the third conductive slug.

An approach to detecting partial discharge events involves retrofitting an electrical system to include a capacitive sensor configured to capacitively sense partial discharge events of a component of the electrical system. The capacitive sensor has a first electrical conductor that forms a first terminal of the capacitive sensor, a second electrical conductor that forms a second terminal of the capacitive sensor, and a dielectric that separates the first electrical conductor and the second electrical conductor. The capacitive sensor generates an electrical sensor signal at an output of the capacitive sensor in response to the partial discharge event. The electrical sensor signal is converted to an optical signal and the optical signal is processed to detect an occurrence of the partial discharge event.

A test device to localize a partial discharge in or at an electrical component may include at least one antenna to capture an electromagnetic wave caused by a partial discharge in the electrical component. The test device includes multiple microphones arranged in an environment around the electrical component. The microphones capture sound waves caused by the partial discharge. It is examined if an intensity of the electromagnetic wave exceeds a first limit value and/or the intensity of the sound wave captured by one of the multiple microphones exceeds a second limit value. Depending on the captured sound wave and/or the electromagnetic wave and on the examination relating to the first and/or second limit value, a location of the partial discharge can be determined.