4results about How to "Reliable resection" patented technology

The application discloses a kind of network type flexible direct system virtual impedance coordination's adaptive current differential protection method, system, equipment and medium, it is related to flexible direct current transmission relay protection technical field.At present, in network type flexible direct system, the problem that sensitivity is insufficient due to the limited output current of converter station.This application includes synchronously collecting the current phasor of the protected line both ends and the effective value of converter station output current;According to the effective value of output current, the virtual resistance parameter of converter station control inner loop is adaptively adjusted;Based on virtual resistance parameter, the adaptive braking coefficient is calculated, so that the braking coefficient is inversely proportional to virtual resistance;Differential current and braking current are calculated, whether differential current is greater than the product of braking coefficient and braking current and action threshold value at the same time is judged, if meet, then determine intra-zone fault and trip.This technical scheme realizes the adaptive improvement of sensitivity at fault, reliable and no misoperation at normal time, without additional judgment link, fast response and easy to realize.

The utility model relates to an internal power supply system of an underground coal mine high-voltage power distribution device, which comprises an input rectifying unit, a first energy storage unit, at least two output circuits and a second energy storage unit, and is arranged in the corresponding high-voltage power distribution device, and the power supply among the internal power supply systems of the high-voltage power distribution devices cannot influence each other. When a certain power supply system goes wrong, the situation that an accident expands cannot occur, and the power supply system does not need to work at high power; the power supply system can supply power to the opening coil, the no-voltage trip coil and the protector through the two output circuits, and the first energy storage unit can be automatically used as a backup power supply under the condition of power failure of the power supply. And under the action of the second energy storage unit, the opening coil can carry out at least one reliable opening operation or the no-voltage tripping coil can carry out at least one reliable no-voltage tripping operation, so that the underground power distribution device can be reliably opened under the condition of alternating current power loss.

The invention discloses a fault direction discrimination method and system under a serious fault of a doubly-fed wind power plant outgoing line, and relates to the technical field of power system relay protection, and the method comprises the steps: obtaining the measurement data of a protection installation part; performing fault phase selection by using the voltage break variable; performing zero crossing point detection on the fault phase current and the memory voltage according to the real-time sampling rate; taking a fixed time window from the respective zero crossing point to carry out similarity calculation; and comparing a similarity calculation result with a setting value, and judging an internal fault. The criterion provided by the invention is suitable for a serious fault scene of the double-fed wind power plant outgoing line, has good quick-action and reliable performance, can effectively solve the problem of direction misjudgment of a phase comparison type directional element in a new energy scene, and is beneficial to reliable removal of the fault of the new energy outgoing line.