596 results about "Single-phase electric power" patented technology

A node within a wireless mesh network is configured to record a zero crossing of alternating current or alternating voltage drawn by a single-phase power consumer and a precise timestamp when the zero crossing occurred, thereby generating timestamped zero crossing data. The node receives similar zero crossing data from a neighboring node. The node then compares the timestamped zero crossing data with the received zero crossing data to determine whether the phase associated with the node is equivalent to, leads, or lags the phase associated with the neighboring node. The node then acquires a positive phase identification associated with the neighboring node. Based on the phase identification, and based on the phase difference between the two nodes, the node infers the phase associated with the single-phase power consumer. That phase indicates the specific power line within a three-phase power distribution network to which the single-phase power consumer is coupled.

The invention provides a flexible island grid-connection control device and method for smart power grids. The device comprises flexible inversion units, single-phase electric power detection units, GPS phase detection units, an island grid-connection detection unit, a communication unit and a master control unit. Each flexible inversion unit comprises an angle form differential voltage topological circuit and a star connection type inverter circuit. Each single-phase electric power detection unit is connected with the output end of the corresponding star connection type inverter circuit and a PCC nodal point. Each GPS phase detection unit is connected to the output end of the corresponding star connection type inverter circuit and a PCC nodal point. The input end of the island grid-connection detection unit is connected to the output ends of the single-phase electric power detection units at the PCC nodal points and the output ends of the GPS phase detection units at the PCC nodal points. The output end of the island grid-connection detection unit is connected with the input end of the master control unit. According to the flexible island grid-connection control device, the flexible inversion units composed of novel topological structures can make a micro power grid and a main power grid conduct flexible grid-connection and conduct switching of islanding modes, so that impact of the micro power grid on the circuits is reduced.

The invention provides dynamic simulation device and method thereof of a super and extra high voltage controllable magnetic control shunt reactor, wherein the dynamic simulation device is capable of accurately simulating magnetic control shunt reactors with different capacities in 500kV, 750kV and 1,000kV power transmission systems. A simulation body consists of three single-phase magnetic control reactors; each single-phase magnetic control reactor is in a three-column structure; two beside core columns are working iron cores; a main alternating current winding and a direct current control coil are wound on each working iron core; and main alternating current windings on the two iron core columns are connected in parallel and connected to a power grid. Control windings are separated from the main windings so as to ensure the safety and the reliability of the device during work. The main windings are provided with twelve turn-to-turn short circuit taps which can respectively simulate 1-25 percent of turn-to-turn short circuit faults from the high-voltage side and the neutral point side; and the control windings are provided with seven turn-to-turn short circuit taps which can simulate 1-25 percent of turn-to-turn short circuit faults from the neutral point side. The body of the device is provided with a current transformer and a voltage transformer on a primary side, which are used for meeting the requirement for protecting a reactor body in a dynamic simulation test.

The invention relates to the field of intelligent meter reading technology, and discloses a transformer district identification system and a transformer district identification method thereof, thereby realizing transformer district identification by means of an existing equipment resource. The system comprises a concentrator and a user meter based on carrier communication, and a transformer district identification instruction in communication connection with the concentrator. The transformer district identification instrument comprises a power supply conversion module which is connected with single-phase power of a transformer end, wherein the power supply output end of the power supply conversion module is connected with a carrier module and a master control unit. A master control chip is connected with a zero-crossing detecting circuit and a pulse excitation generating circuit. Furthermore the zero-crossing detecting circuit and the pulse excitation generating circuit are respectively with phase wires, so that the master control chip triggers the pulse excitation generating circuit to generate a pulse excitation signal for outputting to a corresponding bus when the zero-crossing detecting circuit detects zero crossing of AC power of a corresponding bus after the master control chip receives a transformer district identification instruction that is broadcast by the concentrator through the carrier module.

The invention discloses a damping pad for weakening noises of a unit by tangential vibration of an isolation motor and a single-phase motor mounting structure using the damping pad. A pad body of the damping pad comprises a vibration isolating section, a first damping section and a second damping section, wherein the vibration isolating section is positioned at the middle of the pad body; the first damping section and the second damping section are respectively positioned at two ends of the vibration isolating section; the inside diameter of the vibration isolating section is greater than the inside diameters of two damping sections; an annular groove is formed in the outer circumference of the vibration isolating section; and the width of the annular groove is not greater than the length of the vibration isolating section. The single-phase motor mounting structure comprises connecting bolts and fasteners matched with the connecting bolts; the connecting bolts are used for fixing the damping pad and motor support legs with mounting holes to a mounting foundation; the mounting holes of the motor support legs are in clamped fit with the annular groove on the damping pad; through holes of the damping pad are in clearance fit with the connecting bolts; and in a fastening state, the damping pad has a movable clearance delta in the axial direction. According to the single-phase motor mounting structure, various vibrations of the single-phase motor can be effectively reduced and operation noises are reduced; and the single-phase motor mounting structure can be applied to various household electrical appliance products.

The invention discloses a linear approximation method for a border of static voltage stability domain of an electric power system, relating to the field of the border of the static voltage stability domains. The method comprises the following steps: searching a first electric power system saddle node bifurcation point through a traditional optimal power flow by taking a base power flow as an initial point, and mapping the first electric power system saddle node bifurcation point to a two-dimensional active injection space, so as to obtain the border of the static voltage stability domain; changing a power increase direction towards an increase direction of a power increase direction angle, and calculating a electric power system saddle node bifurcation point in the new power increase direction by virtue of a Lagrangian multiplier method; and ending the calculation when the power increase direction angle is smaller than or equal to 0: carrying out linear approximation on all obtained border points of the static voltage stability domain by virtue of a subsection approximation method, so as to obtain the approximated border of the static voltage stability domain. According to the linear approximation method, the obtained static voltage stability domain preserves relatively high precision, the time consumed for searching single electric power system saddle node bifurcation point byvirtue of the traditional optimal power flow is effectively shortened, and the practical application value for analyzing the stability by virtue of the static voltage stability domain is increased.

The invention relates to a single-phase multi-parameter electric power instrument which can provide a measuring instrument for a single-phase electric power parameter to realize the mensuration of a single parameter or multi-parameter of current, voltage, power factors, active power, reactive power and the like. The instrument comprises a sampling circuit, an electric power measuring circuit, a microprocessing singlechip circuit, a display circuit and a power supply circuit; the sampling circuit is connected with a voltage signal and a current signal; the electric power measuring circuit is connected with the sampling circuit and the microprocessing singlechip circuit; the display circuit is connected with the microprocessing singlechip circuit; and the power supply circuit provides power. The single-phase multi-parameter electric power instrument has the advantages that as the instrument adopts the electric power measuring circuit and the microprocessing singlechip circuit, the instrument has high testing precision and more measuring parameters; and the instrument adopts the mature chip in order to have small power consumption and be suitable for batch production.

The invention discloses an electric heating control system based on power line carrier communication and a working method. The electric heating control system comprises a meter and a plurality of temperature controllers connected in parallel on a power line. On a single-phase power line, the meter performs data management and control on the temperature controllers connected in parallel on the single-phase power line through a power line carrier module. On a multi-phase power line, the meter is connected to a connecting line of each temperature controller and each phase of the power line, and the meter performs data management and control on the temperature controllers connected in parallel on each phase of the power line through the power line carrier module. Data management and control comprise measures of inquiring the target temperature controller which is most suitable for starting and stopping according to the data coupled on the power line and starting or stopping heating of heating equipment connected to the corresponding temperature controller. Power line carrier communication is used in the electric heating control system, so that the defects that wired control needs independent wiring and wireless control is poor in signal are overcome, construction is greatly facilitated, conflicts of wireless signals is avoided, and radiation is reduced.

The invention relates to distribution of electrical power, supervision and security. The invention comprises a power feeding station PFS for delivering electrical power. The PFS comprises a low voltage side LVS, a high voltage side HVS and a transformer TF which is configured to deliver high voltage single phase alternating current on the high voltage side, The power can be distributed, via a cable, to one or more power receiving stations PRS. The cable is configured to distribute current-symmetrical single phase current delivered by the power feeding station. The cable can preferable be a coaxial cable with the shield as current return path. The invention also comprises a current sensor unit CSU which is situated on the high voltage side. The means for measuring characteristics of the current CD can comprise a coil without galvanic contact with the high voltage side. A circuit break unit CBU suitable for breaking the current is situated on the low voltage side. A control function CF is configured to activate the circuit break unit based on the safety rules and the characteristics of the current CD. Characteristics of the current and other system information SI can also be delivered to an information unit IU.

The invention relates to a set of AC phase-changing transformer capable of changing phase number and changing voltage, and a power transmission method of the transformer. The transformer suitable for three-phase and two-phase AC power transmission is characterized in that the transformer can transmit power in a single-phase single-line and grounded manner at the high-voltage side; and the transformer at the power consuming end is also provided with an exciter besides a single-phase winding at the primary side. The transformer is simple, convenient and effective in changing a single-phase power to a three-phase or two-phase AC power meeting the power requirement, thereby relatively lowering the cost for suspending power transmission lines and the facility cost. In addition, the number of windings of the transformer is reduced by obviating phase-to-phase voltage so as to facilitate insulation of the transformer. Accordingly, the transformer provided by the invention is beneficial to improvement on transmission voltage and reduction of cross section area of power transmission wires.

A controller is provided for transitioning a drive signal to a single phase motor between a square wave and pulse width modulation modes, wherein the drive signal is in square wave mode at low motor frequencies and in pulse width modulation mode during normal operation. The transitioning includes using a real time motor model to effectuate transition of the drive signal between the modes, and a sampling rate for sampling the real time motor model during the transitioning. The sampling rate is automatically modified during the transitioning, wherein acceleration of the motor includes transitioning the drive signal from square wave mode to pulse width modulation mode, including periodically increasing the sampling rate during the transitioning. Conversely, when transitioning from pulse width modulation mode to square wave mode, the controller automatically deaccelerates the sampling rate during the transitioning.

The invention discloses a control method for aircraft ground power supply cable voltage drop compensation, which belongs to the technical field of aircraft ground services. The method comprises the steps of building mathematic models for the cable output ends of all single-phase inverters, and obtaining a cable voltage balance relation under a d-q axis system; sampling and calculating each single-phase voltage at the output end of the cable, comparing each single-phase voltage with a given voltage value of each phase at the output end of the cable, and obtaining a voltage drop voltage udown ofeach phase on the power transmission cable through a compensation ring PI regulator; judging whether an output contactor is closed or not and whether the power transmission cable has output voltage or not so as to perform voltage drop compensation; and acquiring a new output voltage given value after voltage drop compensation, and controlling a three-phase six-bridge-arm parallel inverter based on the cable voltage balance relationship and the new output voltage given value, so as to improve the output voltage of the inverter and complete voltage drop compensation. The purpose of ensuring thestability of load voltage is achieved while the problem of voltage drop of the cable is solved.