Abstract: The present disclosure relates to a system and apparatus for monitoring a partial discharge in a switchboard, including a plurality of partial discharge sensors provided in each of a plurality of switchboards to acquire partial discharge data generated in at least one switchboard, and a noise sensor provided in any one of the plurality of switchboards to acquire noise data to be differentiated from the partial discharge data acquired from the at least one partial discharge sensor, and it can be applied to other exemplary embodiments.

Abstract: A method of detecting a partial discharge in an electrical asset includes sensing of a discharge current in the electrical asset using a transducer and responsively providing a transducer output; processing the transducer output by comparing the transducer output to a baseline; calculating an accumulated amount by which the transducer output exceeds the baseline; decreasing the accumulated amount with time; detecting partial discharge in the electrical asset based upon the accumulated amount; and providing an output related to detected partial discharge. A partial discharge detection system for detecting a partial discharge in an electrical asset includes a transducer configured to receive a signal from the electrical asset generated due to an occurrence of partial discharging in the electrical asset and responsively providing a transducer output.

Abstract: A method of detecting a partial discharge in an electrical asset includes sensing of a discharge current in the electrical asset using a transducer and responsively providing a transducer output; processing the transducer output by comparing the transducer output to a baseline; calculating an accumulated amount by which the transducer output exceeds the baseline; decreasing the accumulated amount with time; detecting partial discharge in the electrical asset based upon the accumulated amount; and providing an output related to detected partial discharge. A partial discharge detection system for detecting a partial discharge in an electrical asset includes a transducer configured to receive a signal from the electrical asset generated due to an occurrence of partial discharging in the electrical asset and responsively providing a transducer output.

Abstract: Systems, methods, and computer-readable media are disclosed for identifying a fault using systems and methods for a controlled dynamic MHO characteristic. Particularly, the systems and methods described herein may automatically control the dynamic expansion of the MHO characteristic based on the estimation of uncontrolled dynamic MHO expansion estimation and maximum allowable expansion set by a user. This may provide flexibility in that, the MHO can be allowed to expand to a maximum level, when the estimated MHO expansion value is below the user defined maximum allowable expansion level, but also provides a controlled dynamic MHO when the estimated values are above the maximum allowable level.

Abstract: The present disclosure relates to a method of integration and compensation in a protection relay. The method may include the protection relay: receiving a measured signal from a Rogowski coil and converting the measured signal to digitized samples, where the measured signal is a differentiated current signal over time; iteratively computing integrated current data from the digitized samples using a first digitized function to obtain integrated value; iteratively computing a compensated current data from the integrated current data using a second digitized function to remove a DC component in the integrated current data; evaluating the compensated current data to identify a fault condition; generating a trip signal on identification of a fault condition to operate a switch to electrically disconnect to protect the power equipment. The steps of integration and compensation may be performed in time window that is within the time period of the measured signal.

Abstract: A voltage of a first pin that is one of several pins of an external connector of a system is measured, while the first pin is un-driven except for being pulled to ground through a first resistance, and a second pin of the external connector is being used as a power supply rail of the system. The measured voltage is compared to a short circuit threshold and in response to that threshold being exceeded, the power supply voltage on the second pin is reduced. In such an embodiment, no test stimulus needs to be applied to any of the pins of the external connector. Other embodiments are also described and claimed.

Abstract: A method for feeding electrical power, by a one wind power installation, a power plant or a generation plant, into an electrical supply grid is provided. The grid has a grid voltage having a grid frequency at a grid connection point. In the method a reference system having a reference frequency, a reference phasor having a reference angle, and a reference amplitude of an output voltage are specified. The reference angle revolves at the reference frequency and the reference frequency substantially corresponds to the grid frequency. A phase angle between the output voltage and the grid voltage is specified and an infeed angle is determined. The output voltage is generated having a voltage amplitude depending on the reference amplitude, a frequency depending on the reference frequency and the infeed angle. Tracking of the behavior of the grid voltage is delayed by the reference system.

Abstract: A speed detection device includes a comparator module, a sensor lead with a node connected to the comparator module, and a limit set module. The limit set module is connected to the sensor lead node and to the comparator by an upper limit lead and a lower limit lead to provide upper and lower limits to the comparator that vary according to amplitude variation in voltage applied to the sensor lead.

Abstract: A device, in at least two measuring intervals, detects a respective operating state of at least one power converter of the motor vehicle, which is conductively connected to the traction energy store. The device further comprises a measuring device having a measuring terminal, which is conductively connected or connectable to least one DC voltage pole of an electric traction energy store of the motor vehicle, and a ground terminal which is conductively connected or connectable to a reference potential of the motor vehicle. The measuring device, in the at least two measuring intervals, respectively measures a conductance between the measuring terminal and the ground terminal. The device further comprises a calculation device, which determines the insulation resistances as a function of the at least two measured conductances and the at least two operating states detected.

Abstract: A method of estimating a periodic voltage, such as an input voltage, of one of the phases of an electrical circuit with at least two phases including a voltage sensor for each of its phases, each voltage sensor being capable of outputting a signal representative of at least a part of period of the periodic voltage of the phase. The method including the following steps: measure the representative signal starting from the voltage sensor; amplify the representative signal by a gain determined in the absence of an electrical fault in the circuit and based on a reference voltage common to all phases in the electrical circuit (1); use the amplified representative signal to estimate the periodic voltage. A device for estimating a voltage and an electrical circuit including such a device.

Abstract: A single-phase or multi-phase feed line is connected to a charging connection of the charging station, via which feed line the charge current flows to the charging connection of the charging station regardless of the load capacity identifier of the charge cable. An overload protection device is connected to and monitors the feed line. The overload protection device is an automatically switching overload protection device in which at least one identifier-specific trigger criterion is stored for each of at least two load capacity identifiers of the charging cable. The overload protection device is capable of automatically selecting the identifier-specific trigger criterion assigned to the load capacity identifier depending on the load capacity identifier of the charging cable, and of shutting off a switching device of the overload protection device arranged in the feed line depending on the selected trigger criterion.

Abstract: Systems and a method for detecting potential areas of corrosion under insulation are provided. An exemplary system includes an enclosure, insulation disposed upon an outer surface of the enclosure, and a number of microelectromechanical system (MEMS) sensors. The MEMS sensors detect water proximate to the insulation.

Abstract: A smart circuit breaker for an AC power supply circuit that has a limited capacity for supplying power to one or more electrical loads. Smart circuit breaker includes a sensing circuit to dynamically determine the available load capacity of the AC power supply circuit. A reporting circuit reports the dynamically available load capacity to a controller, an existing electrical load, and/or a potential electrical load on the AC power supply circuit. The AC power supply circuit, the existing electrical load, and/or the potential electrical load can adjust operations based on the reported availability of load capacity.

Abstract: An inrush-current suppressing device includes: a residual-magnetic-flux calculating unit that calculates a residual magnetic flux in a reference phase of a three-phase transformer while assuming a maximum magnetic flux level generated at a time of applying a rated voltage as 1 PU based on a measurement result of a transformer-voltage measuring unit before and after opening a three-phase circuit breaker; a stationary-magnetic-flux calculating unit that calculates a stationary magnetic flux in the reference phase of the three-phase transformer with reference to the maximum magnetic flux level obtained as the 1 PU based on a measurement result of a power-supply-voltage measuring unit, in response to a closing command to the three-phase circuit breaker; and a control unit that actuates a switch of the three-phase circuit breaker corresponding to the reference phase at a timing when the stationary magnetic flux and the residual magnetic flux in the reference phase match each other.

Abstract: A controller (500) in an electric drive system is used to determine whether a phase current imbalance in the output winding of a power generator (204) exists. During operation, the controller (500) receives a set of power generator diagnostic values corresponding to the phase currents output by the power generator (204). Next, the controller (500) determines a set of expected operating phase current values. The controller (500) then compares the obtained diagnostic values to one or more corresponding expected operating values. If the difference is greater than a threshold, the controller (500) provides an appropriate fault indication indicative of a phase current imbalance.

Abstract: Methods and apparatus are presented for detecting phase loss and/or excessive ripple in a power converter, in which bandpass filters are used to obtain harmonic voltage amplitudes associated with the power converter DC bus, and phase loss is detected if a ratio of the second harmonic to the sixth harmonic and/or a ratio of the fourth harmonic to the sixth harmonic exceed predetermined threshold values.

Abstract: A circuit breaker trip unit includes an input section receiving a phase current level signal. A processor is in communication with the input section and generates a first trip signal based on the phase current level signal and user-adjustable trip settings. The trip settings include long time and short time pickup and delay settings. An analog instantaneous trip circuit is in communication with both of the input section and the processor. The analog instantaneous trip circuit includes a digital potentiometer having a non-volatile memory. The potentiometer provides a reference signal corresponding to a resistance setting stored in the memory. The analog instantaneous trip circuit compares the phase current level and reference signals, and generates a second trip signal based on a result of the comparing. The processor programs the resistance setting stored in the memory according to a user-adjustable instantaneous current pickup setting.

Abstract: Processes, machines, and articles of manufacture that may serve to enable the detection or determination of alternating line voltages from an alternating power source, such as the power grid, are provided. This automatic sensing may be useful when connections are made to the power grid, such that when connections are made, the connections may be configured to be compatible with the available power source. This automatic sensing may also be useful if power sources change characteristics over time or if devices may be connected to different power sources over time.

Abstract: There are provided an apparatus and a method for detecting a voltage unbalance and a power meter using the same. The apparatus for detecting a voltage unbalance may a voltage unbalance detection unit including a plurality of voltage unbalance detectors that respectively receive a phase voltage from among a plurality of phase voltages included in input voltages and when the phase voltage is unbalanced, output interrupt signals, and a control unit determining a phase in which an interrupt has occurred, by using a plurality of pieces of accumulated voltage information regarding the plurality of phase voltages output from the plurality of respective voltage unbalance detectors.

Abstract: A three-phase power control apparatus includes a first circuit breaker, a power supply controller, and a three-phase power monitor. When the three-phase power monitor detects an error in three phase voltages provided by a three-phase power supply, the three-phase power monitor transmits a voltage signal to the power supply controller. When the power supply controller receives the voltage signal from the three-phase power monitor, the power supply controller controls the first circuit breaker to disconnect a load from the three-phase power supply. A three-phase power control method is also provided.

Abstract: According to one embodiment, an excitation inrush current suppression device for suppressing excitation inrush currents flowing through a breaker of the three-phase collective operation type for opening and closing connection is configured to measure a three-phase AC voltage of the power supply bus bar to calculate prospective magnetic fluxes of the transformer, and to measure a three-phase AC voltage on the transformer side to calculate residual magnetic fluxes of the transformer after shutoff, so as to set the breaker closed when polarities of the prospective magnetic fluxes respectively agree with polarities of the residual magnetic fluxes in all of the phases respectively.

Abstract: A protection relay is provided for protection of an electric network. The protection relay measures an electric signal in the network, converts the measured signal to a frequency domain representation of the measured signal, and generates a measuring phasor based on the frequency domain representation, where the phase rotation of the measuring phasor is dependent on one or more frequency components present in the measured electric signal. The protection relay compares the measuring phasor to the reference phasor, where the phase rotation of the reference phasor is based on either a nominal or a measured frequency of the electric network, and launches protection if the comparison of the of the measuring phasor and the reference phasor fulfils a predetermined criterion.

Abstract: A circuit protection device and a protection method thereof are provided. The circuit protection device includes a pulse width modulation unit which detects in order for a plurality of current phase of a plurality of transistors. The pulse width modulation unit decides the current phase of the transistors override a first threshold value whether. Then, the pulse width modulation unit sends a control signal to close the transistor that the current phase exceeds the first threshold value, so as to avoid the transistor burn down.

Abstract: A tool for configuring a branch current monitor facilitates mapping the connections of branch circuits to voltage sources in a power distribution panel.

Abstract: A phase-control switchgear includes a circuit breaker, a phase difference detection unit, a storage unit, and a circuit breaker control unit. The phase difference detection unit detects a phase difference between voltages of a specific phase (U-phase) of buses to which three-phase generators are respectively connected, at a plurality of time points. The storage unit stores the detected phase differences. When the three-phase generators are out of synchronization, the circuit breaker control unit estimates a breaking time point at which the phase difference between the voltages of the U-phase of the buses will be in the range of not less than ?80° and not more than 80°, based on the phase differences at the plurality of time points stored in the storage unit. The circuit breaker control unit opens the circuit breaker to break a current at the estimated breaking time point. This makes it possible to suppress a transient voltage generated between electrodes of the circuit breaker after the current is broken.

Abstract: A protection circuit for protecting a dimmer circuit controlling an inductive load including an imbalance detector for detecting an asymmetrical operation in the load and circuit control means for causing the dimmer circuit to reduce a DC component in the load upon detection of the asymmetrical operation. A load imbalance detector is also disclosed having a load DC component detector, a comparator and a signal generating means for generating a circuit shut down signal if the DC component exceeds a pre-set DC threshold.

Abstract: A method and a differential protection apparatus for an electrical link in a medium, high or very high voltage power distribution network. This method, in which two differential protection devices are disposed at the two ends (A, B) of said link, includes a step during which a comparison is made between the current measured locally and the current measured remotely, after said devices have been resynchronized by phase shifting the data received from the end situated remotely by one half of the sum of the outward and return propagation times; and a second step during which, if an angular phase difference is found to exist between two currents after resynchronization, automatic compensation is effected by servocontrolling the angle of the current vectors.

Abstract: A method of determining a fault parameter of a fault on an AC transmission line 10 of a power distribution system 1 relative to a measurement location 12 of the transmission line 10 comprising: measuring a time-dependent current of the transmission line 10 at the measurement location 12; transmitting a current signal indicative of the measured current to a decision logic section 36, the current signal comprising a plurality of pre-fault current values and a plurality of post-fault current values; determining, by the decision logic section 36, a plurality of phase difference values indicative of respective phase differences between respective pre-fault current values and respective post-fault current values; accumulating the plurality of phase difference values into an accumulated phase difference parameter; obtaining the fault parameter by comparing the accumulated phase difference parameter to a threshold value; and outputting the determined fault parameter.

Abstract: A ground fault detection system is provided. The ground fault detection system includes a magnetic core having first and second primary legs and a secondary leg disposed between the first and second primary legs. The ground fault detection system also includes first and second primary windings disposed around the first and second primary legs respectively and configured to introduce current in the first and second primary legs. Further, the ground fault detection system includes first and second secondary windings disposed around the first and second primary legs respectively and configured to detect a ground fault based upon a magnetic flux generated in response to the introduced current.

Abstract: A method of determining out of step condition and an instance of separation within electrical power system. The method does not require user settings and ensures reliable discrimination between recoverable power swing and pole slips that indicates non-recoverable power swing and the need for system separation. The method also allows tripping at a user selected system angle if desired. A calculated angle is used to determine the magnitude of the swing current to control the tripping at the desired angle ? when the system could be safely split after detection of out of step condition based on the criteria of this invention.

Abstract: A circuit protection device and a protection method thereof are provided. The circuit protection device includes a pulse width modulation unit which detects in order for a plurality of current phase of a plurality of transistors. The pulse width modulation unit decides the current phase of the transistors override a first threshold value whether. Then, the pulse width modulation unit sends a control signal to close the transistor that the current phase exceeds the first threshold value, so as to avoid the transistor burn down.

Abstract: A method includes receiving N power signals, each having a different one of N phases, over N power supply lines, where N is an integer greater than two. The method further includes selectively activating a first switch to allow a first current to flow from a first one of the N power supply lines to a second one of the N power supply lines. The method includes generating a signal based on the first current, and selectively generating a phase failure signal when the signal is less than a predetermined threshold.

Abstract: A sensor-less technique is described for detecting the status of an AC contactor of a power inverter. In one embodiment, a method is provided of sensing an unexpected condition of an AC contactor used to couple to a power distribution system a power inverter having at least one power conductor. The method includes determining a voltage value for the conductor; determining a current value for the conductor; determining a phase difference using the voltage value and the current value; and monitoring successive values of the phase difference to produce a monitoring result. Depending on the monitoring result, a determination is made whether or not to issue an alert signal. Control routines embodying such technique may be stored on computer-readable media. A power inverter using such technique is described.

Abstract: Borehole instruments are powered by AC instrument power transmitted on all three phases of a power cable concurrently carrying three phase motor power, the instrument power transmitted at a multiple of the motor power frequency and having a corresponding fraction of the motor power voltage, and received via a capacitive coupling sufficient to withstand high-voltage cable insulation testing. The phase-to-neutral motor power provides approximately the same power level to the borehole instruments if a phase shorts to ground.

Abstract: Network protectors isolate the secondary side of a transformer from a load distribution network. It is useful to have information about the electrical parameters for the transformer and the load side of an open network protector and it is useful to have access to electrical parameters for a closed network protector. Information about a network protector can be provided to a transmitter used to convey information about the transformer associated with that network protector so that information about the network protector can be sent over power liner carrier to a centralized receiver.

Abstract: A method for detecting a fault in semiconductor components in electrical machines, e.g., three-phase generators, used in the automotive field is described. The electrical machine is equipped with multiple windings, each having a phase terminal U, V, W. The electrical machine is checked by determining the voltage in one of its phase terminals U, V, W both during operation and at rest. The phase terminals of phase terminals U, V, W of the electrical machine that are not taken into account are checked for voltage dips with respect to a potential or are checked for the output currents.

Abstract: A method and apparatus for transferring AC electrical power to a load from a first power source to a second power source provides for a time delay in the transfer to avoid problems associated with differences in the phases between the power sources. The phase of the voltage waveform from each power source is sensed continuously, and the phase difference is known at all times, so that it can be used when the transfer is necessary. The method and apparatus monitors the voltage from the first power source, and initiates the transfer from the first power source to the second power source in response to an unacceptable condition from the first power source. The second power source is connected only after waiting for a period of time corresponding to the appropriate time delay.

Abstract: An apparatus includes a first optocoupler and a control module. The first optocoupler selectively allows a first current to flow from a first one of a first pair of N power supply lines to a second one of the first pair. N is an integer greater than two. The N power supply lines each provide a phase signal. The control module controls the first optocoupler and determines an occurrence of a phase failure of the phase signals based on a first signal, which is based on the first current.

Abstract: A control unit of an electric power supply system causes, responsive to a closing command signal, a switch corresponding to R phase to be thrown at a timing when a stationary magnetic flux and a residual magnetic flux of R phase are coincident with each other and then subsequently causes other switches corresponding to S phase and T phase to be thrown at a timing which is delayed from a zero point of an alternating voltage of R phase by a predetermined phase angle of 0-30 degrees, such that the difference of the stationary magnetic flux and the residual magnetic flux of each of S phase and T phase is minimum. Therefore, an exciting incoming current which flows into a three-phase transformer at a time of throwing a three-phase breaker provided with interpole capacitors can be suppressed.

Abstract: Systems and methods that detect a phase loss condition in a three-phase electrical power source are presented. The system includes a detection component that measures and/or monitors a magnitude and frequency of a voltage of a power source, and a controller component that compares measured and/or monitored voltage characteristics to characteristics associated with phase loss.

Abstract: A method for protecting an electrical generator which includes providing an electrical generator which is normally synchronously operated with an electrical power grid; providing a synchronizing signal from the electrical generator; establishing a reference signal; and electrically isolating the electrical generator from the electrical power grid if the synchronizing signal is not in phase with the reference signal.

Abstract: A system for monitoring a circuit breaker that includes a monitoring device in electronic communication with the circuit breaker and a receiving device located separately from the monitoring device. The monitoring device receives data from the circuit breaker and wirelessly transmits at least a portion of the data such as one or more phase currents measured from a network which the circuit breaker protects, an ambient temperature within the circuit breaker, and/or data relating to a trip condition of the circuit breaker. The receiving device receives the transmitted data and displays all or a portion thereof. The monitoring device also includes a display that displays all or a portion of the data.

Abstract: The disclosure relates to a method of detecting the phase-loss state of the three-phase power supply. When the phase-loss condition occurs in the input three-phase power supply of the power converter, it is determined whether the three-phase power source is in the phase-loss state through the characteristic of the frequency and amplitude variations of the ripple voltage of the DC bus, and through the sampling and the continuous detecting of the ripple voltage variations by making use of the sensor of the power converter in cooperation with the software calculation, it is determined whether the three-phase power source is in a phase-loss state. When the detected ripple voltage of the DC bus fulfills the phase-loss conditions, it is determined that the three-phase power source is in a phase-loss state.

Abstract: The subject matter of the present invention is a method of automatically recognizing an electrical system by which both the voltage of an electrical system (2) and the phase angle between phases of the system are monitored so that human technical failure upon connecting a plant (1) to said electrical system (2) be reliably prevented.

Abstract: Provided is an apparatus and method for providing differential protection for a phase angle regulating transformer having a load side and a source side in a three-phase power system. The method includes calculating a first positive sequence component and a first negative sequence component associated with incoming secondary currents detected on the source side, calculating a second positive sequence component and a second negative sequence component associated with outgoing secondary currents detected on the load side, applying a phase angle shift to the second positive sequence component and the second negative sequence component to form a compensated positive sequence component and a compensated negative sequence component, respectively, and determining an operate current value and a restraint current value for each of a positive and negative sequence differential element of the differential protection based on the compensated positive sequence component and the compensated negative sequence component.

Abstract: The present invention is directed to a method and apparatus for improving operational reliability during a loss of a phase voltage (LOV) in a multi-phase power system, wherein a voltage representative of the LOV phase is calculated. The representative voltage is used for computing a reference polarizing voltage suitable for a protection unit.

Abstract: Respective contact terminals in respective arc-suppressing spaces of respective breakers are opened at a voltage zero point of any phase of three phases, simultaneously among the three phases. If current breaking is carried out for the three phases at the same time, when the breakers of the three phases are opened, the residual magnetic levels of the respective phases of a transformer can be controlled so that the residual magnetic flux level of the phase opened at the voltage zero point is maximum (for example, ?2K or +2K) and the residual magnetic flux level of the other two phases are opposite in polarity to the residual magnetic flux level of the phase concerned and equal to substantially the same residual magnetic flux (for example, +K and +K or ?K and ?K) which is equal to about one half of the residual magnetic flux level of the phase concerned.

Abstract: In one embodiment of the invention, a reverse phase control power switching circuit for controlling the flow of current through a load from an AC source comprises a sensing bridge in series with the load and the AC source. The conductive state of the sensing bridge is responsive to a pulse generator and a zero crossing detection and overload protection means. Phase control means coupled to the pulse generator determines turn off of the sensing bridge is reset by the zero crossing detection and overload protection means. Responsive to a load current condition exceeding a maximum current caused by an overload or a short, the zero crossing detection and overloading protection network terminates conduction of current through the sensing bridge. The sensing bridge starts conducting current to the load at the beginning of the AC cycle and continues to conduct to a desired AC voltage phase angle or earlier if an excessive current condition caused by an overload condition or a short occurs.

Abstract: To the end of providing a constant AC voltage to a variable load (1) which is arranged remote of a voltage source (3), a voltage drop over an electrical supply line (2) which connects the load to the voltage source (3) is compensated for by a compensation AC voltage which, if added to the constant AC voltage, results into the output AC voltage Ufull of the voltage source (3) and the value of which is varied depending on the absolute value of the alternating current (I) conducted to the load (1) and on the phase angle phi between the output AC voltage Ufull of the voltage source (3) and the alternating current (I).

Abstract: A polarity protection circuit contains a metal oxide semiconductor field effect transistor (FET) that pets its control voltage via an electrical connection from supply voltage lines and a transistor that pets its control voltage via another connection from the supply voltage lines. When a supply voltage has a wrong polarity the FET is in a non-conducting state. If in the supply voltage lines during normal operation there occurs a short circuit that tends to chance a direction of the current, the transistor rapidly discharges a gate charge of the FET, and the current flow in the wrong direction is prevented.