139results about "Frequency selective voltage/current level measurement" patented technology

Some embodiments can concern an apparatus configured to detect an electrical state of one or more electrical devices. The one or more electrical devices are coupled to an electrical power infrastructure and generate one or more high-frequency electrical signals on the electrical power infrastructure. The apparatus can include: (a) a processing module configured to run on a processor of a computational unit; and (b) a sensing device configured to be coupled to an electrical outlet. The sensing device can have: (a) a data acquisition receiver configured to receive the one or more high-frequency electrical signals via the electrical outlet and convert the one or more high-frequency electrical signals into one or more first data signals when the sensing device is coupled to the electrical outlet. The electrical outlet can be electrically coupled to the electrical power infrastructure. The sensing device is in communication with the computational unit. The processing module is further configured to identify the electrical state of the one or more electrical devices at least in part using the one or more first data signals. The high-frequency electrical signals comprise electrical signals in the ten kilohertz to three megahertz range. Other embodiments are disclosed.

The disclosure relates to a meter for monitoring usage of power provided by a power transmission system to a site. The meter comprises: a meter module connected to a power feed associated with the power transmission system to provide readings relating to the power; a messaging module to provide messages to the power transmission system; a connection to an alternating current (AC) power supply; a rectifier circuit connected to the AC power supply to generate a direct current (DC) power signal; a capacitive circuit connected to an output of the rectifier circuit, the capacitive circuit including a capacitor for storing a voltage for temporarily providing replacement power for the rectifier circuit; and a switching regulator circuit connected to the output of the rectifier circuit and the capacitive circuit, the switching regulator converting the DC voltage signal to a stepped down voltage signal for the meter module.

An earth clamp for testing contact voltage, comprising a measuring circuit formed of a voltage inducing transformer and a current measuring transformer, adapted to be mutually coupled by an earth conductor whose earth impedance is to be measured, a microcontroller to deliver an alternating voltage to the voltage inducing transformer and, in response, to receive a reference voltage generated in the earth conductor and an earth current i_B+i_F induced in the current measuring transformer, the microcontroller being configured to extract an amplitude E of the reference voltage, an amplitude I_B and an amplitude I_F of the earth current and a phase shift φ between the reference voltage and the loop current i_B and to calculate the earth impedance Zb at a determined frequency, the microcontroller also computing the contact voltage Uc at said determined frequency by the product of the earth impedance times the amplitude I_F.

A system (10) is provided herein for monitoring the harmonic content of the RF signal delivered to an RF powered device (13). The system comprises (a) a voltage transducer (16) adapted to sample the voltage of the RF signal and to output a first signal representative thereof, (b) a current transducer (17) adapted to sample the current of the RF signal and to output a second signal representative thereof, and (c) a memory device (67) in communication with at least one, and preferably both, of the aforementioned transducers 16 and 17 and which contains calibration information specific to the transducers.

Disclosed is a method of signal detection. A received input signal is divided into a frame unit and each input signal present in a first frame and a second frame is transformed into a frequency signal. Then, first power spectrum information and second power spectrum information are computed utilizing the transformed frequency signal and a delta spectrum entropy value corresponding to a difference of the two computed power spectrum information is obtained. A predetermined input signal is included in a predetermined frame among the input signal after judging through comparing the delta spectrum entropy value with a critical value. Desired signal can be detected in a noisy environment including a noise signal by using the delta spectrum entropy value.

Disclosed herein is a Fourier transform-based phasor estimation method and apparatus capable of eliminating the S influence of exponentially decaying DC offsets. According to a Fourier transform-based phasor estimation method according to an embodiment of the present invention, an input signal is sampled, and samples of one-cycle data of the input signal are separated into at least two sample groups. A Discrete Fourier Transform (DFT) is performed on each of the sample groups. A DC offset included in the input signal is calculated on a basis of results of the DFT on each of the sample groups, and an error caused by the DC offset is calculated using the calculated DC offset. A phasor of a fundamental frequency component included in the input signal is estimated by eliminating the calculated error, caused by the DC offset, from the results of the DFT on the input signal.

Apparatus and methods for detecting stray voltage anomalies in electric fields are provided herein. In some embodiments, an apparatus for detecting an electrical field may comprise: at least one sensor probe for generating data corresponding to an electrical field detected by the at least one sensor probe, wherein the at least one sensor probe comprises at least one electrode; a processor, coupled to the at least one sensor probe, for analyzing the data to identify a voltage anomaly in the electric field; and an indicator, coupled to the processor, for alerting a user to a presence of the voltage anomaly in the electric field.

The invention discloses a comprehensive monitoring and early warning device and early warning method for equipment temperature in a wind power plant box-type transformer substation bin. The device comprises a wireless temperature monitoring unit, a wired temperature monitoring unit, a humidity monitoring unit, a transformer oil temperature measurement unit, a shell temperature measurement unit, anenvironment temperature detection unit, an operation current and voltage monitoring unit and a CPU operation control alarm unit which are arranged at different points of equipment in the box-type substation bin. The comprehensive temperature estimation calculation and three-level early warning judgment method considers the historical temperature, current real-time temperature, temperature changerate, equipment environment temperature, humidity and operation current of each operation equipment. According to the historical temperature value, the real-time sampling value and the temperature change rate of a certain measuring point, rapid temperature prediction and estimation are carried out; then comprehensive temperature calculation is carried out according to the influence of the environment temperature, humidity and load current; and finally, a three-level early warning judgment formula is formed based on mutual constraint of the calculated value and a time constant value, real-timeprediction and estimation comprehensive calculation and alarming are conducted on different temperature monitoring points of the equipment, and meanwhile corresponding judgment and early warning are conducted on humidity exceeding the standard and excess current.

A silicon device, e.g., a nanoelectromechanical resonator, has a silicon substrate; an oxide layer having a trench therein; a silicon device layer over the oxide layer; and a nanowire disposed at least partly over the trench. Substantially no oxide or polysilicon is over the nanowire in the trench. A polyimide layer over the silicon device layer includes an opening over the trench. A silicon device can include silicon-on-insulator layers and at least one complementary metal-oxide semiconductor transistor in addition to a nanowire substantially suspended over a trench. A system for measurement of a nanoresonator includes an AC source in series with the nanoresonator to provide an electrical signal thereto at a selected first frequency. Electrode(s) adjacent to and spaced apart from the nanoresonator are driven by voltage source. A detector detects a current through the nanoresonator.

Integrated current sensors are used in DC electric power systems. An integrated current sensor (200B) according to one embodiment comprises: a DC inductor (111B) including a resistive component and an inductive component, wherein a DC current passes through the DC inductor (111B); an integrator circuit (161), the integrator circuit (161) receiving a voltage associated with the DC inductor (111B); and a feedback system operationally connected to the DC inductor (111B) and to the integrator circuit (161), to subtract a voltage associated with the resistive component and obtain a voltage associated with the inductive component.

An oscillation detecting apparatus for detecting oscillation of a signal includes a high pass filter for generating an alternating current signal from which a direct current component of the signal is removed, a slicing circuit for generating a limit signal which results from restricting an amplitude level of the alternating current signal to a level lower than a predetermined level, an integration circuit for integrating a waveform of the limit signal during a predetermined period, and a comparator for detecting whether or not the signal oscillates based on a value of the waveform integrated by the integration circuit.

A device for filtering a carrier frequency of a PWM waveform. The device includes a low-pass filter for converting the PWM waveform into an analog signal. The device further includes a sampling analog-to-digital converter receiving the analog signal from the low-pass filter and the device also includes a controller for causing the non-integrating analog to digital converter to sample the PWM waveform at the pulse frequency rate thereby rejecting the carrier frequency. As already stated the PWM waveform includes a pulse which has a leading edge, a top portion, and a trailing edge. In one embodiment, the controller causes the A/D converter to sample during the top of the pulse. Preferably, the controller causes the A/D converter to sample at substantially the center of the pulse.

An AC/DC voltage measuring instrument is operable in a DC mode, an AC mode, or an automatic mode. In the DC mode, an input terminal is coupled directly to an analog-to-digital converter, which generates a digital output signal indicative of the amplitude of the received signal. In the AC mode, the input terminal is coupled to an RMS circuit through a capacitor. The RMS circuit generates an output signal having an amplitude indicative of the RMS amplitude of the received signal, and this output signal is coupled to the analog-to-digital converter. In the automatic mode, the input terminal is also coupled to the RMS circuit, but it is coupled to the RMS circuit without being coupled through the capacitor. The input terminal is coupled to the RMS circuit through an amplifier, and a calibration procedure is used to compensate for any offset of the amplifier.

A sensor (11) comprises an inductor (18) for sensing an alternating current signal component of an observed signal. The inductor (18) comprises a substrate, conductive traces associated with different layers of the substrate, and one or more conductive vias for interconnecting the plurality of conductive traces. A magnetic field sensor (20) senses a direct current signal component of the observed signal. A first filtering circuit (26) has a high-pass filter response. The first filtering circuit (26) is coupled to the inductor (18) to provide a filtered alternating current signal component. A second filtering circuit (28) has a low-pass filter response. The second filtering circuit (28) coupled to the magnetic field sensor (20) to provide a filtered direct current signal component. A sensor fusion circuit (30) determines an aggregate sensed current based on the filtered alternating current signal component and the filtered direct current signal component.

A current sensor is provided for measuring DC current in a primary conductor also carrying AC current. The current sensor includes a ferromagnetic core through which the primary conductor may extend. The core has a narrow air gap formed therein and a magnetic flux sensor is disposed in the air gap. A secondary winding is mounted to the core and has an impedance connected therein. The impedance has a value of substantially zero at one or more frequencies of the AC current. The impedance may be a short or an impedance source that includes a capacitor and an inductor.

Bias tees, according to certain embodiments of the present invention, include switches in the AC signal path, the DC signal path, or both, to improve the capability of the bias tees to be used for high impedance AC measurement, low current DC measurement, or both. Optical control of the switches, as well as control of the switches using a DC bias present within the AC signal input to the bias tee, is described. Including a set of diodes into the DC signal path, rather than a switch, provides enhanced capability of the bias tee to be used for high impedance AC measurements.

The invention discloses a circuit scheme for an alternating-current and direct-current electric leakage detection system, wherein the circuit is capable of completing direct-current electric leakage detection, alternating-current electric leakage detection and electric leakage sampling link self-detection and the like. The circuit scheme mainly comprises an LDO module for converting externally inputted power supply voltage into a voltage required by electric leakage detection, a frequency division module for carrying out frequency division on a high-frequency clock signal, a logic control module for driving an MOS tube and controlling switching of different working modes, an MOS tube driving module for driving an external electric leakage detection coil, an electric leakage detection coilfor sensing alternating-current and direct-current electric leakage signals and electric leakage self-detection signals, a sampling resistor for converting a current signal flowing through the electric leakage detection coil into a voltage signal, a PGA module for amplifying the sampling signal, a gain control module for controlling the amplification factor of the PGA, an ADC module for carrying out digital-to-analog conversion on the signal, a DSP module for processing alternating-current and direct-current electric leakage signals and electric leakage self-checking signals and a current limiting module for limiting loop currents.