A power-meter includes a digital signal processor (DSP) configured to determine a respective consumed energy within each of a plurality of predetermined contiguous time intervals, a dequantizer, and a pulse generator. The dequantizer is configured to, for each time interval, determine a sum of a remainder and the consumed energy, calculate an integer pulse-count by dividing the sum of the remainder and the consumed energy by a predetermined pulse-quantum, calculate a new remainder by subtracting the product of the integer pulse-count and the pulse-quantum from the sum, and replace the remainder by the new remainder The pulse generator is configured to, for each time interval, generate the integer pulse-count number of pulses of an indicator signal.

A monitoring method uses an electricity meter arranged to measure an electricity consumption of an installation and including a current limiter arranged to selectively limit a current supplied to the installation. The monitoring method includes he steps, repeated each current day, for each current period of a predetermined set of at least one successive period defined in the current day, of: verifying a first predetermined condition associated with said current period; if the first predetermined condition is verified, activating the current limiter to limit the current supplied to the installation until the end of said current period.

A vehicle information terminal is used in a vehicle equipped with an energy converter for converting an external energy to an electric power. The vehicle information terminal includes a management unit that generates a power generation information associated with a vehicle position and a power generation amount of the energy converter. The management unit is operative to transmit the power generation information to an external device. A transmission condition of the power generation information of the management unit is set so that transmission frequency of the power generation information during travel of the vehicle is higher than transmission frequency of the power generation information during stop of the vehicle.

Methods and arrangements for computing disruptive current in a transformer. Transformer current is measured, and disruptive current is predicted. Based on the active transformer current and predicted disruptive current, a predicted reactive power and predicted neutral current are determined. At least one corrective action, to be taken with respect to the transformer, is thereupon identified. Other variants and embodiments are broadly contemplated herein.

A wireless electric power sensing device can include a communication unit configured to communicate with an external device; a measuring unit configured to measure power consumption information corresponding to a plurality of devices located within a target space; and a central control unit configured to detect a point in time when one or more square waves are included in the power consumption information, determine reactive power based the power consumption information, identify an electric heating device from among the plurality of devices within the target space based on a rate of change in the reactive power, determine when an operation time of the electric heating device exceeds a predetermined amount of time based on a change in the power consumption information, and in response to the operation time of the of the electric heating device exceeding the predetermined amount of time, transmit, via the communication unit, identification information for the electric heating device and information about the operation time of the electric heating device to the external device.

The invention provides an electric grid state estimation system and method based on a boundary fusion. The system includes an electric grid data acquisition module, a communication module including a local data unit and a state estimation unit, and a data fusion module, wherein the state estimation unit includes a memory storing a state estimation program and a display displaying a program running and outputting a state variable; the state estimation program is performed to realize an electric grid state estimation; the estimation method includes the following steps of dividing a regional electric grid, then establishing a measurement equation for each region, solving an internal quantity and a boundary quantity, fusing the boundary quantities of two regions, correcting the boundary quantity, performing a non-linear transformation on the intermediate variable, solving the estimated values of the state variable by the least square method, and performing outputting.

The accuracy of photovoltaic simulation modeling is predicated upon the selection of a type of solar resource data appropriate to the form of simulation desired. Photovoltaic power simulation requires irradiance data. Photovoltaic energy simulation requires normalized irradiation data. Normalized irradiation is not always available, such as in photovoltaic plant installations where only point measurements of irradiance are sporadically collected or even entirely absent. Normalized irradiation can be estimated through several methodologies, including assuming that normalized irradiation simply equals irradiance, directly estimating normalized irradiation, applying linear interpolation to irradiance, applying linear interpolation to clearness index values, and empirically deriving irradiance weights. The normalized irradiation can then be used to forecast photovoltaic fleet energy production.

The present invention relates to a method and an apparatus for detecting, from a smart plug, an electronic device connected to the smart plug, and more specifically, to a method and an apparatus for detecting a change in an electronic device connected to a smart plug. A method, according to one embodiment of the present invention, is the method for detecting a connected electronic device from the smart plug and comprises the steps of: inspecting whether pre-trained data is present when the an electronic device is connected; inspecting whether the connected electronic device and the pre-trained data match when the pre-trained data is present; a training step of obtaining information on valid power, invalid power, and power factor when the connected electronic device and the pre-trained data do not match; and saving trained data after the training is complete.

A method of monitoring power usage of a load includes defining one or more parameters of the load that vary with a mode of operation of the load, receiving measurement data related to the one or more parameters of the load over a first period of time, recording the measurement data, determining a plurality of groups, each group defining a set of measurements in a continuous range of values, each group having a lower threshold value and an upper threshold value, the lower and upper threshold values defined by having less than a minimum threshold number of recorded measurements of the lower and upper threshold values, and associating a mode of operation with each of the plurality of groups.

A device for extinction angle control of a high voltage direct current (HVDC) system, includes: a converter reactive power calculator calculating a reactive power variation amount of a converter included in the HVDC system, depending on firing angle control of the converter; an alternating current (AC) system short circuit level calculator calculating a short circuit level of an AC system by applying the reactive power variation amount to a short circuit level formula of the AC system connected to the HVDC system; an extinction angle variation value calculator calculating an extinction angle variation value of the converter, corresponding to the short circuit level; and an extinction angle controller controlling an extinction angle of the converter, depending on an extinction angle control value reflecting the extinction angle variation value.