Systems and methods for measuring the integrity of insulation components in energized or de-energized electrical systems. Using a digital modulation/demodulation system, an active monitoring system adds a modulated high frequency signal to an injected signal and demodulates the resulting signal to provide voltages and currents that are measured and used to determine the capacitances and power factors of the insulation components. Systems may be used for on-line detection and measurement of power factor and capacitance of electrical equipment such as transformers, reactors, and condenser type bushings. The present disclosure is especially applicable to the electrical power industry.

A method monitors capacitor bushings for an AC mains. The mains has first-third phases, associated with first-third mains lines, capacitor bushings, and mains voltages. Each capacitor bushing has a conductor, surrounded by foil, connecting its mains line. The method includes: at a first instant, for each phase: a first reference voltage phasor is determined; and a foil voltage present between the respective foil and ground potential is detected and a corresponding first foil voltage phasor is determined; at a second instant, for each of the phases: a second reference voltage phasor is determined; the foil voltage is detected and a second foil voltage phasor is determined; for each capacitor bushing: a loss factor change is calculated based on the respective reference voltages and foil phasors and those of the adjacent capacitive bushing; and a monitoring signal is generated based on a comparison of the loss factor and a tolerance value.

The invention generates a model of the composition of the cable segments in a network. Different cable compositions have different loss distributions. Each cable segment is given a starting cable composition (based on cable records if available), and thus can be represented as a loss distribution. The loss for each circuit can be measured (by measuring Hlog), and thus can also be represented as a loss distribution. Updates are made to the loss distribution for each segment so that the loss distributions that make up each circuit is consistent with that of the (measured) loss distribution for that circuit. These updates are preferably performed as Bayesian updates of each cable segment (loss distribution) using Gibbs sampling (i.e. the other cable segment loss probabilities are fixed whilst the probability for the segment under consideration is updated).

A pest sensor and a detector for use in a pest sensing system are described. The pest sensor comprises a processor configured to: receive a first signal indicative of a first impedance across a first sensing circuit; receive a second signal indicative of a second impedance across a second sensing circuit; and in response to detecting that one of the first or second signals differs from the other by more than a predefined difference threshold, output an indication of pest activity.

Systems and methods for measuring the integrity of insulation components in energized or de-energized electrical systems. Using a digital modulation/demodulation system, an active monitoring system adds a modulated high frequency signal to an injected signal and demodulates the resulting signal to provide voltages and currents that are measured and used to determine the capacitances and power factors of the insulation components. Systems may be used for on-line detection and measurement of power factor and capacitance of electrical equipment such as transformers, reactors, and condenser type bushings. The present disclosure is especially applicable to the electrical power industry.

A method of determining the capacitance and loss-factor of each of a plurality of capacitive components of an electrical power device, wherein the method includes: a) obtaining for each capacitive component a respective capacitance value and loss-factor value, and b) processing the capacitance values and the loss-factor values, wherein the processing involves removing a common influence of temperature on the capacitance values from the capacitance values and removing a common influence of temperature on the loss-factor values from the loss-factor values to obtain for each capacitive component a temperature-compensated capacitance value and a temperature-compensated loss-factor value.

A test apparatus includes a host compliance printed circuit board having a first circuit plane and a second circuit plane separated by at least one dielectric layer. A first row of surface mount pads are disposed on the first circuit plane. The first row of surface mount pads includes a first pad and a second pad. A second and third row of surface mount pads are disposed on the first circuit plane. A first and second differential pair of circuit lines is disposed on the first circuit plane. The first differential circuit line has one end coupled to the first pad. The second differential circuit line has one end coupled to the second pad. The first and second differential pair of circuit lines extend from the first and second pads and between the second and third rows of surface mount pads.

A mobile tester is provided for Very Low Frequency (VLF) testing of a measurement object, which has means for generating an AC voltage which has an effective amplitude of greater than or equal to 1 kV and a frequency in the range of between 0.01 and 1 Hz, a connection element for connecting the measurement object, and means for measuring and evaluating the test voltage applied to the measurement object and the test current caused thereby. In a first operating mode, the tester autonomously carries out a VLF test using the test voltage generated. The tester also has a communication interface for emitting a synchronization signal or for receiving an externally generated synchronization signal, and the tester is set up, in a second operating mode, to synchronize the generated test voltage with the test voltage generated by at least one further tester of the same type.

A method monitors capacitor bushings for an AC mains. The mains has first-third phases, associated with first-third mains lines, capacitor bushings, and mains voltages. Each capacitor bushing has a conductor, surrounded by foil, connecting its mains line. The method includes: at a first instant, for each phase: a first reference voltage phasor is determined; and a foil voltage present between the respective foil and ground potential is detected and a corresponding first foil voltage phasor is determined; at a second instant, for each of the phases: a second reference voltage phasor is determined; the foil voltage is detected and a second foil voltage phasor is determined; for each capacitor bushing: a loss factor change is calculated based on the respective reference voltages and foil phasors and those of the adjacent capacitive bushing; and a monitoring signal is generated based on a comparison of the loss factor and a tolerance value.

A method of determining the capacitance and loss-factor of each of a plurality of capacitive components of an electrical power device, wherein the method includes: a) obtaining for each capacitive component a respective capacitance value and loss-factor value, and b) processing the capacitance values and the loss-factor values, wherein the processing involves removing a common influence of temperature on the capacitance values from the capacitance values and removing a common influence of temperature on the loss-factor values from the loss-factor values to obtain for each capacitive component a temperature-compensated capacitance value and a temperature-compensated loss-factor value.