5 results about "Phase currents" patented technology

The invention discloses a wire single-phase earth fault single-end ranging method using a ranging scale minimum principle. The method includes: measuring fault-phase voltage, fault-phase current and fault-phase negative-sequence current and zero-sequence current at a transmission line protecting mounting position; selecting initial fault distance as 1x which is increased gradually by a step length delta 1, sequentially calculating ranging scale e (1x) of each point in the whole transmission line, and selecting the distance from the point with the smallest ranging scale e(1x) to the transmission line protecting mounting position as fault distance. Physical features of transmission line voltage and current transmission are described through distribution parameters, ranging precision is unaffected by transmission line ground capacitors, and the method is applicable to single-phase earth fault single-end ranging of transmission lines of optional voltage grades, especially applicable to single-phase earth fault single-end ranging for transmission lines with ultrahigh voltage.

The invention discloses a switched reluctance motor variable winding driving system and an online soft switching method, and belongs to the field of online soft switching. The system comprises a controller, a driving module, a power converter and a variable winding module, the variable winding module provided by the invention can change the connection mode of each coil in the phase winding of theswitched reluctance motor on line. According to the invention, a switched reluctance motor driving topological structure with online winding series-parallel connection switching capability is combinedwith an online soft switching method; through the variable winding module, the connection mode of the phase windings of the switched reluctance motor is changed on line, so that the control of the phase inductance value is realized, and the optimization of the torque performance of the motor at a low speed and the performance improvement of the motor at a high rotating speed are effectively realized; on-line series-parallel connection switching and fault winding removal of a winding coil are carried out by utilizing an interval with zero phase current of the switched reluctance motor, so thaton-line soft switching is realized, and the speed adjustment range and the motor fault tolerance capability are expanded.

The invention discloses an intelligent series-parallel reactive power compensation component-based power grid distributed-control system and an implementation method for the same. The system consists of one or more intelligent components and an upper computer, wherein each intelligent component can be independently used, and is provided with a three-phase current and voltage sampling circuit for a three-phase power system, a power controller, and a plurality of switches and reactive power compensation devices, which are controlled by the power controller. The system and the method are characterized in that the power controllers are used for controlling each switch in three-phase reactive power compensation units of the power system to realize series compensation as well as parallel compensation according to sampling results respectively. The distributed-control system is high in reliability. According to the system and the method, voltage of a power grid can be boosted, the stability of the power grid can be improved, reactive power can be compensated, and meanwhile, the unbalance of active power can be regulated.