In the spark plug heat rating measurement method and system based on spark discharge current active heating, the spark plug is installed in a constant-temperature water jacket cooling chamber with a specific torque. A constant spark discharge current control module is connected to the high-voltage terminal of the spark plug, to provide real-time controlled discharge current to heat up the high-voltage central electrode of the spark plug. During the spark discharge process, the temperature change of the high-voltage central electrode and the surrounding ceramic insulator are measured by a temperature detection module and used to determine the heat rating of the spark plug. By real time adjusting the discharge current level of the spark plug, or providing a same amount of spark energy to the spark gap, the heat ratings of spark plugs with different ceramic insulation structures can be evaluated through the temperature changes during discharge or after discharge.

In the spark plug heat rating measurement method and system based on spark discharge current active heating, the spark plug is installed in a constant-temperature water jacket cooling chamber with a specific torque. A constant spark discharge current control module is connected to the high-voltage terminal of the spark plug, to provide real-time controlled discharge current to heat up the high-voltage central electrode of the spark plug. During the spark discharge process, the temperature change of the high-voltage central electrode and the surrounding ceramic insulator are measured by a temperature detection module and used to determine the heat rating of the spark plug. By real time adjusting the discharge current level of the spark plug, or providing a same amount of spark energy to the spark gap, the heat ratings of spark plugs with different ceramic insulation structures can be evaluated through the temperature changes during discharge or after discharge.

An arc detection system for an aircraft high voltage and direct current electrical circuit which includes a sensor sensing high-frequency magnetic fields created by current pulses, a signal conditioning block, a database including a time threshold, status signals of events occurring in aircraft normal operation procedures, a processing unit configured to calculate a statistical dispersion of the high-frequency magnetic fields of the current pulses of the signals measured by the sensor, calculate a threshold under no-arc conditions as a function of the previous measured signals, check if the signals measured by the sensor are above the threshold under no arc-conditions during the time threshold, if positive, check if any status signal of events due to normal operation procedures has been activated, and if negative, activate the operation of an electrical protection.

An arc detection system for an aircraft high voltage and direct current electrical circuit which includes a sensor sensing high-frequency magnetic fields created by current pulses, a signal conditioning block, a database including a time threshold, status signals of events occurring in aircraft normal operation procedures, a processing unit configured to calculate a statistical dispersion of the high-frequency magnetic fields of the current pulses of the signals measured by the sensor, calculate a threshold under no-arc conditions as a function of the previous measured signals, check if the signals measured by the sensor are above the threshold under no arc-conditions during the time threshold, if positive, check if any status signal of events due to normal operation procedures has been activated, and if negative, activate the operation of an electrical protection.

A deterioration degree diagnosis device includes a measurement unit and a diagnosis unit. The measurement unit measures an impedance related to a contact resistance of an electrical connection portion by measuring an AC voltage between metal members and an AC current flowing between the metal members in a state where an AC signal of a predetermined frequency is applied to an electric circuit that connects two metal members in contact via the electrical connection portion. The diagnosis unit diagnoses a deterioration degree of the electrical connection portion based on a reactance component value in the impedance measured by the measurement unit.

A deterioration degree diagnosis device includes a measurement unit and a diagnosis unit. The measurement unit measures an impedance related to a contact resistance of an electrical connection portion by measuring an AC voltage between metal members and an AC current flowing between the metal members in a state where an AC signal of a predetermined frequency is applied to an electric circuit that connects two metal members in contact via the electrical connection portion. The diagnosis unit diagnoses a deterioration degree of the electrical connection portion based on a reactance component value in the impedance measured by the measurement unit.

A method and a test apparatus for determining the elements of a dielectric equivalent circuit diagram for an insulation of an electric system and to an insulation monitoring device. All data points of the system's step response are stored for a measuring period T.sub.m, and fault resistance R.sub.f and an initial value C.sub.e0 of leakage capacitance C.sub.e are calculated. After this determination of fault resistance R.sub.f and initial value C.sub.e0, the elements of absorption element R.sub.a and C.sub.a and leakage capacitance C.sub.e are determined by numeric signal processing by using an approximation algorithm which continuously simulates the recorded step response. For simulating the step response, a transfer function G(s) modelled by the equivalent circuit diagram having equivalent circuit diagram elements R.sub.f, C.sub.e, R.sub.a, C.sub.a and measurement resistance R.sub.m is formed analytically and the output signal is calculated, which is described using transfer function G(s), by means of the step function.

A method and a test apparatus for determining the elements of a dielectric equivalent circuit diagram for an insulation of an electric system and to an insulation monitoring device. All data points of the system's step response are stored for a measuring period T.sub.m, and fault resistance R.sub.f and an initial value C.sub.e0 of leakage capacitance C.sub.e are calculated. After this determination of fault resistance R.sub.f and initial value C.sub.e0, the elements of absorption element R.sub.a and C.sub.a and leakage capacitance C.sub.e are determined by numeric signal processing by using an approximation algorithm which continuously simulates the recorded step response. For simulating the step response, a transfer function G(s) modelled by the equivalent circuit diagram having equivalent circuit diagram elements R.sub.f, C.sub.e, R.sub.a, C.sub.a and measurement resistance R.sub.m is formed analytically and the output signal is calculated, which is described using transfer function G(s), by means of the step function.

Systems and methods for detecting and identifying arcing are disclosed. A method of detecting arcing includes obtaining data indicative of voltage and data indicative of current, determining a waveform of a cycle of a primary load current according to the data indicative of current, determining at least one noise signal according to the determined waveform of a cycle of the primary load current and the data indicative of current, determining a probability density of the noise signal according to a time window, and comparing the probability density of the noise signal with at least one model probability density.

Systems and methods for detecting and identifying arcing are disclosed. A method of detecting arcing includes obtaining data indicative of voltage and data indicative of current, determining a waveform of a cycle of a primary load current according to the data indicative of current, determining at least one noise signal according to the determined waveform of a cycle of the primary load current and the data indicative of current, determining a probability density of the noise signal according to a time window, and comparing the probability density of the noise signal with at least one model probability density.