46 results about "Power factor measurement" patented technology

The present invention discloses a system for transferring electrical power between a grid and at least one vehicle. The vehicle can be Battery Electric Vehicle (BEV), Plug-in Hybrid Electric Vehicle (PHEV) or Fuel Cell Vehicle (FCV). The type of vehicle will be recognized and controlled by the system to support demand response and supply side energy management. Vehicle recognition can be carried out by load signature analysis, power factor measurement or RFID techniques. In an embodiment of the invention, the grid is a Smart Grid. The present invention also discloses a method for facilitating electrical power transfer between the grid and the vehicle.

A smart metered light fixture including a light source. The light fixture includes a surge protection device with a monitor that indicates when surge protection fails. The light fixture includes a power supply monitor configured to collect real-time AC current, voltage, and power factor measurements from a power supply. An operational characteristic monitor monitors an operational characteristic of the light source, such as current consumption, wattage, real-time temperature, a brightness level, and / or an efficiency of the light fixture. A communication device positioned between the power supply receives information from the monitors and wirelessly transmits information regarding the monitored operational characteristic and information and / or power supply measurements to a remote user equipment. The communications device may also receive control instructions from the remote user equipment for controlling aspects of the light source.

The present invention discloses a system for transferring electrical power between a grid and at least one vehicle. The vehicle can be Battery Electric Vehicle (BEV), Plug-in Hybrid Electric Vehicle (PHEV) or Fuel Cell Vehicle (FCV). The type of vehicle will be recognized and controlled by the system to support demand response and supply side energy management. Vehicle recognition can be carried out by load signature analysis, power factor measurement or RFID techniques. In an embodiment of the invention, the grid is a Smart Grid. The present invention also discloses a method for facilitating electrical power transfer between the grid and the vehicle.

An automatic power factor correction system, for an electrical power installation drawing varying levels of reactive power, measures an electrical parameter of the power drawn by a load of a power installation using a power measurement integrated circuit, the parameter being capable of indicating a level of reactive power drawn by the load, and couples a combination of capacitors to the power line to compensate for the level of reactive power indicated by the electrical parameter measured. In a first embodiment of the invention, the combination of power factor compensating capacitors is calculated from a signed value of reactive power drawn by the load. In a second embodiment, the compensating capacitor combination is calculated from a value of power factor for the load which is calculated from a ratio of an active power value to an apparent power value.

The invention discloses an interval integration measurement method of a low-voltage electric apparatus short-circuit tolerance intensity test power factor. The method includes the following steps that: step 1, a current value i (t2) and a frequency f at the interval boundary of a current waveform integral in a specific interval [t1, t2] after a loop is turned on are measured, wherein the current waveform integral is expressed by a symbol described in the descriptions of the invention, t1 and t2 are two specific points on a predicted short-circuit current waveform diagram, and t1 is a switching-on time point, and when t1 is equal to 0, the direct current component of current waveforms should be attenuated to be a negligible level as for t2, and the time difference of t1 and t2 should be the whole period length of periodic components and can be expressed as an equation that omega*(t2-t1)=2pif*(t2-t1)=n*2pi, wherein n is a positive integer, and i (t) is the magnitude of current in the line at the t time point; and step 2, the current waveform integral, i(t2) and f are substituted into an equation described in the descriptions of the invention, and the power factor of the loop is solved. The measurement method of the invention is simple and is only related to current and frequency measurement accuracy, and therefore, the introduction of more errors can be avoided; the power factor measurement range of the method is wider compared with a three extreme point method; and therefore, the interval integration measurement method of the invention has the advantages of simplicity, high accuracy, high reliability and wider measurement range.

Disclosed herein is a power measurement system capable of power of electric devices without performing a quantization process through a separate analog-digital converter for voltage. The power measurement system includes a smart meter measuring a voltage root mean square value input to an electrical device; and a power measurement device measuring power of the electrical equipment using a voltage root mean square value Vrms measured by the smarter meter and a current instantaneous values of power lines connected to the electric device.

The invention discloses an intelligent electric meter switchable in function. The intelligent electric meter comprises a housing and a panel, wherein a display module is arranged on the panel, and a storage module, an alarming module, a processor, a communication module, an electric meter operation switching module, a settlement module and a parameter measuring module are arranged in the housing. The storage module comprises an E2PROM memorizer. The alarming module comprises a low-electric-quantity alarming module and a failure alarming module. The communication module comprises a remote signal receiving module and a signal feedback module. The settlement module comprises a settlement memorizer. The electric meter operation switching module comprises a charging module, a money charging module and a switching module. The parameter measuring module comprises a voltage measuring module, a current measuring module, an active power measuring module and a power-factor measuring module. Compared with the prior art, a money charging mode of the intelligent electric meter can be switched, returning and resetting are avoided, time is saved for a user, and the intelligent electric meter is convenient to use and wide in application range.

The compensating device includes power supply circuit and cascaded voltage sampling circuit, selective switch circuit, A / D conversion circuit and main control CPU. Reset storage circuit and display circuit are connected to the main control CPU. Characters are that the main control CPU is connected to power factor measurement circuit, circuit for switching compensation capacitances, infrared communication circuit, and communication control CPU. The said communication control CPU is connected to transmitter receiver set of signal. Advantages are simple structure, reasonable design, high intelligence, reliable quality, good maintainability and easy of standardization etc.

The invention relates to a power compensation device, in particular, an intelligent three-phase split reactive power compensation device. The intelligent three-phase split reactive power compensation device comprises a fuse group, a three-phase power factor measurement unit, a switching switch group, a compensation capacitor group and an ARM micro controller. The three-phase power factor measurement unit, the compensation capacitor group and the ARM micro controller are combined together, so that the intelligent three-phase split reactive power compensation device can be designed. With the intelligent three-phase split reactive power compensation device adopted, a fast, high-precision, impact-free and three-phase independent reactive power compensation control effect can be effectively realized under the operation of a power grid. The intelligent three-phase split reactive power compensation device can be widely applied to urban and rural civil power grids where three-phase power supply unbalance exists, and can ensure that the power factor of each phase of the three-phase power grids can approximate to or achieve 1, effectively improve the power supply efficiency of the power grids and improve the power supply quality of the power grids.

A circuit apparatus measures, records, transmits, and displays actual and estimated power consumption in a branch circuit of an electrical distribution system. The apparatus includes a display driver coupled to one or more current sensors which derives or estimates power consumption from measured current. The accuracy of power consumption is improved by additional measurement of actual supplied voltage. A plurality of current sensors determine differential current to provide ground fault interruption to a desired range of precision. A store enables display of surge and average current measurements and power measurements in addition to immediate results.

The present invention provides an electric power system power factor measuring device, an electric power system power factor measuring method and a short circuit test system. An electric power system comprises a power supply line, a protection switch, a power transformer and a short circuit switch, and the power factor measuring device comprises a voltage transformer of which the primary side is connected with the power supply line; a voltage measuring device used for obtaining a first voltage waveform of the secondary side of the voltage transformer and a second voltage waveform of the secondary side of the power transformer simultaneously when the protection switch is located in a closed state and the short circuit switch is located in a disconnection state and used for obtaining a third voltage waveform of the secondary side of the voltage transformer when the protection switch is located in the closed state and the short circuit switch is located in the closed state; a current measuring device used for obtaining a current waveform of the secondary side of the power transformer when the protection switch is located in the closed state and the short circuit switch is located in the closed state; and a data processing device used for calculating a power factor. According to the present invention, the power factor when the electric power system is in short circuit can be measured more accurately.

The invention provides an intelligent AVC system adjustment method. The adjustment method comprises the steps: (1) an AVC system calculates a reactive output reference value of the current wind powerplant and a voltage of a common connecting point according to the voltage, current, and power factor measurement values and a power factor angle reference value of the common connecting point when thepower grid satisfies the requirement of the common connecting point of the wind power plant; (2) reactive output constraint is calculated, and if the reactive output upper limit value in the wind power plant is greater than the reference value and the voltage of the common connecting point is greater than a limiting value, a dynamic reactive compensation apparatus separates from AVC system control, and a constant voltage mode is switched; and (3) when it is detected that the voltage of the common connecting point is recovered to the normal range and when the reactive output in the wind powerplant is declined to be less than the reference value, the dynamic reactive compensation apparatus maintains the current state, and prepares to receive an ACV system instruction, and the AVC system performs steady state mode operation according to the current power grid dispatching instruction. A corresponding intelligent AVC system adjustment apparatus is disclosed for optimizing the current voltage reaction automatic adjustment, lowering power grid loss, improving voltage quality, lowering cost in voltage reactive optimizations adjustment and prolonging the service life of the adjustment equipment.

A small-sized power factor measurement apparatus capable of measuring a power factor by one element is desired. The power factor measurement apparatus includes a pair of coupling ends (12) for coupling to a power supply in parallel with a load, two magnetic elements (21, 22) whose changes in electric resistance are different from each other due to the same external magnetic field, a pair of measurement terminals (13) for outputting a differential voltage between the two magnetic elements, a power factor sensor (10) including a pair of sensor terminals (10t) connected to the pair of coupling ends (12), a voltage detector (15) for measuring a voltage between the measurement terminals (13), a low-pass filter (16) connected to the output of the voltage detector (15), a high-pass filter (17) connected to the output of the voltage detector (15), a rectifier (18) connected to the high-pass filter (17), and a divider (19) for dividing the output of the low-pass filter (16) and the output of the rectifier (18).

A direct power control system of a high power factor induction motor realizes energy-saving control of a three-phase induction motor under the condition of light load or no load. The direct power control system of the high power factor induction motor comprises a controller using a digital signal processor TMS320F2808 as the core, a three-phase bridge power amplification device, a three-phase bridge driving circuit, the three-phase induction motor, a three-phase diode rectifier, a power factor detecting link, a current detecting link, an encoder rotating speed detecting link, a power factor measuring link, a + 24V switching power supply, a +15V switching power, a + / - switching power supply, a +5V switching power and the like. By means of the direct power control system applying power factor measurement, the stator flux linkage amplitude of the three-phase induction motor under the condition of light load or no load is controlled, instantaneous reactive power of the motor is adjusted, and therefore the motor power factor is effectively improved and a good energy-saving effect is achieved.

The invention provides an energy-saving and emission-reduction intelligent underground transformer. The energy-saving and emission-reduction intelligent underground transformer comprises a shell, a side-mounted oil level gauge and a multifunctional transformer protector; the side-mounted oil level gauge and the multifunctional transformer protector both are mounted on the sidewalls of the shell. The output signals of the oil level gauge, an overvoltage alarm device, a gas alarm device and a temperature alarm device are transmitted to a network via a communication interface by use of a controller so that a central management computer connected in the network is capable of remotely monitoring each underground transformer, and as a result, transformer current differential protection, transformer differential current quick-break protection, transformer overcurrent backup protection, overvoltage protection, current measurement, voltage measurement, temperature measurement, power factor measurement and harmonic measurement are realized; in case of alarm events such as open circuit, short circuit, overload, overheat, undervoltage and power failure, corresponding processing is carried out locally and alarm information is transmitted to the central management computer by use of a network interface, and therefore, lots of underground transformer parameters can be monitored centrally.

The invention presents a method for measuring the power factor of a variable-frequency power supply. After angular frequency tracking becomes stable, the real-time fundamental signal phase is calculated according to the angular frequency convergence value and the state variable, and then, the voltage and current phase difference and the power factor can be obtained. Compared with the prior art, the method of the invention has the advantages as follows: the fundamental frequency of a variable-frequency power supply can be tracked dynamically; the result of power factor measurement is not affected by harmonic; no complex phase locked loop circuit is needed; the requirement on signal stability is not high; and the instantaneous frequency, amplitude and apparent power can be measured simultaneously.

Systems and methods are disclosed herein to a power factor adjuster comprising: a power factor measurement unit configured to measure the power factor on an input line to a load and generate a power factor correction signal based on the measured power factor; and a power factor adjustment unit connected to the power factor measurement unit comprising: a fixed capacitor connected in series to a first switching device; and an adjustable element having a variable capacitance connected in parallel to the fixed capacitor and in series to a second switching device, wherein the overall capacitance of the power factor adjustment unit is adjusted by adjusting the capacitance of the adjustable element or by toggling the first and second switching devices in response to the power factor correction signal.

A distributed-circuit intermediate protection integrated device comprises an incoming line terminal, an incoming line side lightening arrester, a fuse protector, a multifunctional power meter, a current transformer, a current terminal row, a residual current operated circuit-breaker, a common-compensation capacitor switch, a self-healing power capacitor, an outgoing line side lightening arrester and an outgoing line terminal which are all installed in a stainless steel box in sequence. The distribution-circuit intermediate protection integrated device is installed on a low-voltage distribution circuit between distribution unit-area overall protection and household protection, the fault point can be isolated once ground fault occurs to a certain branch circuit, failure outage to other circuits never occurs, and power supply continuity and reliability of residential users is guaranteed; the device has a lightning protection function, an electric leakage protection function, and meter, voltage, current and power factor measurement and reactive local compensation functions; overlapping investment can be avoided, and the distribution-circuit intermediate protection integrated device is timesaving, laborsaving, safe and high in operation efficiency.

The invention relates to a method for dynamically adjusting voltage and a device thereof, wherein the device comprises a power factor measurement control module connected with the control end of a star-delta automatic switching device and the control end of a voltage-adjusting transformer and used for measuring the power factor of an alternating current machine. The method comprises: calculating the power factor of the machine according to measured current and voltage phase differences of the alternating current machine; and controlling the output voltage of the voltage-adjusting transformer of the input end of the alternating current machine according to the power factor. The method for dynamically adjusting voltage and the device thereof are capable of automatically adjusting voltage according to the load state of the machine so as to further save energy, improve the power factor and increase the service efficiency of a power supply system without influencing the rotating speed of the machine.

The invention discloses a three-phase asynchronous motor load torque and power factor measurement system and method. The system comprises a microprocessor module, a voltage sensor set and a current censor set. The voltage sensor set comprises a phase A voltage sensor, a phase B voltage sensor and a phase C voltage sensor. The current sensor set comprises a phase A current sensor, a phase B current sensor and a phase C current sensor. An input end of the microprocessor module is connected with a phase A signal conditioning circuit, a phase B signal conditioning circuit and a phase C signal conditioning circuit. An output end of the microprocessor module is connected with an LCD circuit. The method comprises the steps of signal real-time collection and transmission, signal preprocessing, and three-phase asynchronous motor load torque calculation and output. The system and the method are designed reasonably, can be achieved conveniently with a low cost, and is convenient for use and operation, high in working reliability and practicality, good in timeliness and use effect, and easy to promote and use.

The invention belongs to the technical field of circuit measurement and discloses a power factor measurement circuit. The power factor measurement circuit comprises a zero-crossing comparison circuit,a phase difference measurement circuit, an average value filtering circuit, a voltage conversion circuit, a CPU (Central Processing Unit) and an A / D (Analogue / Digital) conversion terminal acquisitioncircuit, wherein the phase difference measurement circuit comprises a multi-way selection switch; after alternating current Iin of a detection loop and alternating voltage Uin of the detection loop pass through the zero-crossing comparison circuit respectively, a first square wave signal and a second square wave signal are output respectively; the first square wave signal is input to a C end od the multi-way selection switch and the second square wave signal is input to a con end od the multi-way selection switch; an H end of the multi-way selection switch is grounded; an output end of the multi-way selection switch is connected with an input end of the average value filtering circuit; the output end of the average value filtering circuit is connected with the input end of the voltage conversion circuit; the output end of the average value filtering circuit is connected with the CPU and the A / D conversion terminal acquisition circuit. The power factor measurement circuit provided by the invention is suitable for measuring power factors of an electric power system, the requirements on an input signal are not high and an applicable range is greatly enlarged.

Provided is a 485 communication control type intelligent reactive compensation controller. The invention relates to a 485 communication control type intelligent reactive compensation controller and provides a low-voltage three-phase four-wire intelligent reactive power automatic compensation controller. The 485 communication control type intelligent reactive compensation controller comprises a power supply circuit and a 485 communication circuit, a computer terminal and a GPRS module. The 485 communication control type intelligent reactive compensation controller further comprises a power factor measuring circuit, a compensation capacitor switching circuit, an infrared communication circuit and a communication control CPU which are connected with a main control CPU. The communication control CPU is connected with the 485 communication circuit, the 485 communication circuit is connected with the computer terminal, and the computer terminal is connected with the GPRS module through a 485 serial port. The 485 communication control type intelligent reactive compensation controller has the advantages of high intelligent level, flexible use, complete functions, reliable quality, good timeliness, reliability, capacity scalability and maintainability, and easy standardized and normalized management.

The invention discloses a power factor measuring device, which comprises a voltage input channel, a Hall multiplier connected with the voltage input channel, a third voltage amplifying device connected with the Hall multiplier, a filter and an AC DC conversion device connected with the output end of the voltage amplifying device, a divider connected with the filter and the AC DC conversion device and a digital voltmeter connected with the divider. The power factor measuring device of the invention has the advantage that a simple and reliable power factor measuring method which can carry out online monitoring continuously can be provided.

The invention discloses an equivalent period fitting measurement method for a low-voltage electric appliance product short circuit tolerance intensity test power factor. According to a principle thati(t) consists of a periodic component Imsin([omega]t+[phi]u-[phi]) and an exponential decay component Imsin([phi]u-[phi]).e<-R / L.t>, the periodic component is a constant value on equal period intervalmoment on an i(t) curve, the Imsin( [phi]u-[phi]) is a constant value after a test loop is closed and therefore the i(t) can be equivalent to i(t)=A+B.e<-t / T> (wherein A, B and T are all constants),multiple groups of equal period current values i(t) are subjected to the curve fitting of a specific exponential decay function i(t)=A+B.e<-t / T>, and a great quantity of power factor measurement calculation values are obtained; then, a linear fitting method is used, a power factor numerical value with highest occurrence frequency is selected from the power factor calculation values to serve as a final test loop power factor; and therefore, an influence brought by unstable current measurement accuracy and frequency is avoided. The measurement method is simple, and measurement accuracy is high.