39 results about "Inrush current limiter" patented technology

The invention relates to a reactor type short-circuit fault current limiter, which consists of reactors, a capacitor, a switch and lightning arresters. During the stable state of an electric grid, the current limiter works at a series resonance or series compensation status and is of low impedance; and after the electric grid is subjected to short-circuit fault, windings of the reactors are saturated due to overcurrent, or meanwhile, the change of the reactance of the reactors is controlled through closing the switch, so that the current limiter generates high impedance to realize fault current limiting. According to the current limiter, the automatic fault response is realized through the saturation of the reactors, and the current-limiting capacity is improved through circuit resonance; meanwhile, the manufacture cost of a system can be greatly lowered through the reasonable design of a current limiter structure; and the current limiter is strong in current-limiting capacity and has little influence on the electric grid, and the safety and the reliability of the operation of the electric grid are effectively improved.

A device for limiting the inrush current component of a current provided by a supply to a load, the device including an impedance arranged between the supply and the load, a switch arranged to divert the current from the impedance, an inrush period timer connected to the supply and arranged to activate the switch after expiry of an inrush time period, the inrush time period being a time period beginning upon the supply becoming active such that current is available to be provided by the supply to the load and a reset circuit connected to the supply and the inrush period timer, the reset circuit arranged to deactivate the switch and reset the inrush period timer in response to the supply becoming inactive such that no current is available to be provided by the supply to the load.

The invention discloses a coordination and protection method and device of DC grid having a resistive type superconductive current limiter. The resistive type superconductive current limiter is put into a fault discharging loop. The method comprises the steps of obtaining a first impedance scope of the resistive type superconductive current limiter when the fault discharging loop reaches to the over-damping state; obtaining a second impedance scope of the resistive type superconductive current limiter when the fault current of the fault discharging loop begins to be attenuated; obtaining a third impedance scope of the resistive type superconductive current limiter based on the movement time of a master breaker in a DC breaker; obtaining the impedance value of the resistive type superconductive current limiter based on the first impedance scope, the second impedance scope, and the third impedance scope. The invention is advantageous in that through selecting the impedance value of the superconductive current limiter, the fault current can be effectively inhibited; it can be guaranteed that the DC breaker can reliably turn off the fault current, and the voltage and current stress ofa switch member can be reduced.

The invention discloses a method for calculating short-circuit current of a power network with a high-temperature superconducting current limiter, comprising the steps of establishing a short-circuitcurrent calculation method with a high-temperature superconducting current limiter and a high-temperature superconducting current limiter; Short-circuit current calculation model of FCL; inputting grid data and fault information into the model; simplifying the original network; constructing the admittance matrix of the simplified network; triangulating the admittance matrix; solving the voltage vector by the forward-backward substitution method; recalculating the impedance of the nonlinear branch according to the voltage vector, and updating the admittance matrix; calculating the sum of the currents of adjacent branches of the fault node, and further calculating the current deviation; judging whether the current deviation is less than a preset threshold value, and if so, completing the calculation; injecting the three-sequence currents of the fault node and the bus at both ends of the current limiter into the linear network, and solving the other bus voltages and branch currents. The technical proposal provided by the invention has the advantages of simple calculation, accurate result, strong practicability and the like, and can provide the basis for the safety and stability analysis of the electric network containing the high-temperature superconducting current limiter, the relay protection setting calculation and the like.

The invention provides a short-circuit fault limiter based on rectifier capacitor current nature commutation. The device is characterized by establishing a current limiter topological structure through theoretical analysis and pre-estimating feasibility, carrying out formula derivation to analyze in detail a current limiting process, and finally, carrying out simulation experiment to verify current limiting performance. The current limiting process of a current limiter can experience three stages: a short-circuit current normal rising stage before switch action, a brief commutation and voltage stabilization stage of a full-bridge rectifier capacitor charging circuit, and a current-limiting inductor complete involvement current-limiting stage. Normal operation of a power grid is not influenced when the current limiter does not act; after the current limiter acts, a short-circuit current value can be reduced greatly, and bus voltage drop is reduced obviously; a current-limiting inductor (L) and a charging capacitor (C) have an optimal coordination relationship, and thus an optimal current limiting effect can be achieved; and the device is low in harmonic content and has no hazard overvoltage.

The invention provides a capacitive commutation hybrid fault current limiter and a control method thereof. The capacitive commutation hybrid fault current limiter comprises an on-state low-loss branch, a current transfer branch and a current limiting branch. A semi-controlled device is simple in logic and economical and reliable. The hybrid fault current limiter is low in loss of the steady state,has a bidirectional current limiting capability and can effectively inhibit the short-circuit current of a DC grid; the locking time of a sub module IGBT is delayed to obtain enough time for motion of other protection devices; it is ensured that a current limiting resistor and a corresponding heat-dissipating device can be fully utilized to improve the current limiting effect. The control methodof the capacitive commutation hybrid fault current limiter comprises two conditions of the normal operation of the DC line where the current limiter is located or before detection of the generation offaults of the DC line where the current limiter is located or after detection of the generation of faults of the DC line where the capacitive commutation hybrid fault current limiter is located to achieve control for a resistance-inductive capacitor commutation hybrid current limiter.

A System and a method are disclosed for suppressing rush current noise in a power switch cell. The system comprises: a power switch (306) having an operational condition dependent upon the state of a control signal; and an inrush current limiter module (300) for outputting the control signal. The control signal transitions from a first value to an intermediate value and from the intermediate value to a second value, wherein the power switch is configured to operate in a low conductive (OFF) condition when the control signal has the first value, to operate in a high conductive (ON) condition when the control signal has the second value, and to operate in a moderately conductive condition when the control signal has the intermediate value. Therefore, when the power switch transitions from the OFF condition to the ON condition, the rush current noise may be reduced.