The invention relates to a method for personal protection during high-voltage testing on a test object, the method comprising the steps of outputting a high-voltage alternating current for the test object by means of a high-voltage generation device, which has a high-voltage transformer for generating the high-voltage alternating current. The method further has the steps of determining a curve over time of at least one electrical variable at the high-voltage transformer during the output of the high-voltage alternating current, and ending the output of the high-voltage alternating current on the basis of the curve over time of the at least one electrical variable.

The invention relates to a method for personal protection during high-voltage testing on a test object, the method comprising the steps of outputting a high-voltage alternating current for the test object by means of a high-voltage generation device, which has a high-voltage transformer for generating the high-voltage alternating current. The method further has the steps of determining a curve over time of at least one electrical variable at the high-voltage transformer during the output of the high-voltage alternating current, and ending the output of the high-voltage alternating current on the basis of the curve over time of the at least one electrical variable.

A method of monitoring electrical faults includes processing features of signals output by sensors of a circuit breaker about electrical properties of a circuit coupled with a load and transitioning between states of operation based on the processed features. The states include a normal state, a fault state, and a trip state, wherein the state remains in the normal state until the processed features no longer satisfy normal criteria, after which the state transitions to the fault state, wherein the state transitions back to the normal state when a trip condition is not satisfied, and transitions from the fault state to the trip state when the trip condition is satisfied. The method further includes detecting a warning event when the state transitions from the normal state to the fault state and back to the normal state and outputting a warning event notification upon detection of the warning event.

Systems and methods for testing a lightning protection circuit are provided. Aspects include providing an alternating current (AC) test signal source coupled to a circuit under test, the circuit under test comprising a lightning protection circuit having a threshold voltage, a first filter, and a second filter, providing a direct current (DC) voltage supply in series with a filtering device, the filtering device coupled to the AC test signal source, providing a first capacitor coupled between the AC test signal source and the circuit under test, operating the DC voltage supply and the AC test signal source to provide a first test signal to the circuit under test, wherein the first test signal comprise a first voltage that exceeds the threshold voltage, measuring a first impedance of the circuit under test responsive to providing the first test signal, wherein the first impedance corresponds to the first filter.

A photovoltaic energy system and a method for detecting a ground insulation impedance, improve accuracy of detecting a ground insulation impedance after one or more conversion circuits are connected in parallel. The photovoltaic energy system includes one or more conversion circuits and a detection circuit. The detection circuit includes an alternating current signal source and a sampling resistor that are connected in series, a first sampling circuit, and a control circuit. The control circuit is configured to control the alternating current signal source to output harmonic signals of a first frequency and a second frequency. The first sampling circuit is configured to: when the alternating current signal source outputs the harmonic signal of the first frequency, collect a voltage at both terminals of the sampling resistor to obtain a first voltage.

A photovoltaic energy system and a method for detecting a ground insulation impedance, improve accuracy of detecting a ground insulation impedance after one or more conversion circuits are connected in parallel. The photovoltaic energy system includes one or more conversion circuits and a detection circuit. The detection circuit includes an alternating current signal source and a sampling resistor that are connected in series, a first sampling circuit, and a control circuit. The control circuit is configured to control the alternating current signal source to output harmonic signals of a first frequency and a second frequency. The first sampling circuit is configured to: when the alternating current signal source outputs the harmonic signal of the first frequency, collect a voltage at both terminals of the sampling resistor to obtain a first voltage.

A system includes: a sensor configured to detect electrical signals of a cable section for transmitting electrical energy; a processor; a data memory; and a signal interface. The data memory stores a set of curves with an associated distance to the sensor and representing a pulse response of an electrical pulse predetermined by a cable model as a result of a modeled partial discharge at the associate distance. The sensor detects a discharge signal caused by an actual partial discharge on the cable section, and transmits a measurement signal to the processor. Based on the first measurement signal, the processor determines which among the curves in the set correlates best with the first discharge signal, as the first discharge curve. The processor determines a sensor distance between the actual partial discharge and the sensor based on the distance associated with the discharge curve. The signal interface transmits the sensor distance.

A system includes: a sensor configured to detect electrical signals of a cable section for transmitting electrical energy; a processor; a data memory; and a signal interface. The data memory stores a set of curves with an associated distance to the sensor and representing a pulse response of an electrical pulse predetermined by a cable model as a result of a modeled partial discharge at the associate distance. The sensor detects a discharge signal caused by an actual partial discharge on the cable section, and transmits a measurement signal to the processor. Based on the first measurement signal, the processor determines which among the curves in the set correlates best with the first discharge signal, as the first discharge curve. The processor determines a sensor distance between the actual partial discharge and the sensor based on the distance associated with the discharge curve. The signal interface transmits the sensor distance.

The present disclosure discloses a single-phase fault arc detector. A fault arc signal processing circuit performs processing to obtain a voltage square wave signal, a voltage sine wave signal, a current sine wave signal, a current square wave signal, a current square shoulder pulse signal, and a current high-frequency pulse signal, and a processor accurately determines, on the basis of the plurality of obtained current signals and voltage signals and in combination with a preset operation rule, whether there is a single-phase fault arc in a power utilization line. Correlated characteristics of square shoulder parts may be accurately recognized by accurately extracting the current square shoulder pulse signal from current sampling signals; then, characteristics such as the number and durations of the square shoulder parts as well as current values may be comprehensively recognized on the basis of the current square shoulder pulse signal and the current high-frequency pulse signal.

The present disclosure discloses a single-phase fault arc detector. A fault arc signal processing circuit performs processing to obtain a voltage square wave signal, a voltage sine wave signal, a current sine wave signal, a current square wave signal, a current square shoulder pulse signal, and a current high-frequency pulse signal, and a processor accurately determines, on the basis of the plurality of obtained current signals and voltage signals and in combination with a preset operation rule, whether there is a single-phase fault arc in a power utilization line. Correlated characteristics of square shoulder parts may be accurately recognized by accurately extracting the current square shoulder pulse signal from current sampling signals; then, characteristics such as the number and durations of the square shoulder parts as well as current values may be comprehensively recognized on the basis of the current square shoulder pulse signal and the current high-frequency pulse signal.