A method and a device are provided for monitoring an electrical power supply network. A temporal frequency change value is determined for at least two sections or for at least two points of the power supply network. The frequency change value indicates the respective temporal frequency change of the network frequency. A conclusion is drawn regarding a possible islanding within the power supply network, and a warning signal which indicates the possible islanding within the power supply network is generated when the difference between the frequency change values, exceeds a predetermined frequency change threshold value.

In an example, a system for determining a power factor of an electric device powered by an alternating current (AC) power is described. The system includes a current sensor configured to: (i) remotely sense, at a position external to the electric device, a magnetic field formed by the AC power in the electric device, and (ii) determine, based on the sensed magnetic field, a current of the AC power. The system also includes a voltage sensor configured to, at a position external to the electric device, remotely measure a voltage of the AC power. The system further includes a computing device communicatively coupled to the current sensor and the voltage sensor, the computing device being configured to: (i) determine a phase delay between the current and the voltage, and (ii) determine, based on the phase delay, a power factor of the electric device.

A method for synchronizing opening of a circuit breaker is presented. The circuit breaker is arranged to interrupt a current to an inductive load. The method is performed in a control device (2) and comprises measuring (S100) a reference signal as a function of time for a circuit breaker (1) connected to an inductive load (5), obtaining (S110) an indication of a power factor of the inductive load through the circuit breaker, determining (S120) an arcing time for opening of the circuit breaker, the arcing time being dependent on the obtained indication of a power factor, predicting (S130) a zero crossing of a current through the circuit breaker based on the measured reference signal, and providing (S140) contact separation of a contact pair of the circuit breaker at a point of time before the predicted zero crossing, the point of time being determined by the determined arcing time and the predicted zero crossing. A control device, a circuit breaker arrangement, and a computer program for synchronizing opening of a circuit breaker are also presented.

Building automation systems, energy meters, and associated methods. A method includes receiving a plurality of voltage inputs and a plurality of current inputs from a multiphase power source. The method includes selecting a first voltage input from the plurality of voltage inputs. The method includes performing a signed power factor computation between respective pairs of the first voltage input and each of the plurality of current inputs. The method includes identifying a pair with a greatest positive power factor value. The method includes designating the identified pair with the greatest positive power factor value as an associated phase pair.

A system for indicators of power meters.

Methods of operation of a self-powered power sensor (SPPS) are provided for the measurement of the likes of current, power, power factor, and other parameters related to the power consumption, at points of interest, such as circuit breakers, machines, and the like. Each SPPS is enabled to communicate its respective data, in an environment of a plurality of such apparatuses, to a management unit which may further process the data sent thereto, as well as communicate back to the SPPS for the purpose of synchronization of, for example, clocks of the SPPS and the management unit.

A signal generating device for generation of measurement signals for an electrical system includes a housing which features an electrically conducting material, an energy reservoir arranged in the housing, a data interface arranged at the housing and designed to receive signal data, a coupling interface arranged at the housing and coupled to the electrical system, and a signal generator arranged in the housing. The signal generator is coupled to the electrical energy reservoir, to the data interface and to the coupling interface. The signal generator is designed, based on the signal data, to generate the measurement signals and to output them via the coupling interface. A corresponding measuring device is also included.

A baseboard management controller (BMC) installed in a server or other hardware device may perform operations to monitor and safeguard metering data for one or more hardware component of a server that includes the BMC. The BMC may periodically transmit a metering data message over a network to an event destination, where the metering data message includes the utilization levels of the hardware component during a period of operation. In response to detecting a loss of communication with the event destination, the BMC may perform lossy compression of the monitored utilization levels for the hardware component, wherein the lossy compression produces a utilization value that is representative of the monitored utilization levels, but uses less data storage capacity. The utilization value may be transmitted to the event destination instead of the monitored utilization levels in response to determining that communication with the event destination has been reestablished.

A signal adjustment device includes a frequency adjustment circuit, a filter circuit, and a power estimation circuit. The frequency adjustment circuit is configured to receive a two-tone signal from a signal generator and to generate a first signal according to the two-tone signal, wherein the signal generator generates the two-tone signal according to a first coefficient and a second coefficient. The filter circuit is configured to filter the first signal, in order to generate a second signal. The power estimation circuit is configured to detect a power of an intermodulation distortion from the third order signal component, which is associated with the two-tone signal, in the second signal, and to adjust at least one of the first coefficient and the second coefficient according to the power, in order to reduce the power.

The present disclosure is directed to systems and methods for controlling an electrical system using setpoints. Some embodiments include control methods that monitor an adjusted net power associated with the electrical system and adjust the setpoint based on a comparison of the adjusted demand to the setpoint. If the adjusted demand has not exceeded the demand setpoint, the setpoint is reduced. If the adjusted demand has exceeded the demand setpoint, the setpoint is increased.