30 results about "Current theory" patented technology

The invention discloses a substation relay protection hidden fault diagnosis method based on multidimensional mixture, which belongs to the technical field of substation protection. The method comprises the following steps: S1, collecting multidimensional parameters in an SV data transmission network, including m current sampling voltages Up and m current sampling currents Ip collected in a period T; S2, calculating the mean square error of the current actual electricity consumption Qp according to the m current sampling voltages Up and the m current sampling currents Ip; S3, judging whether the mean square error of the current actual electricity consumption Qp is greater than an electricity threshold Delta Q; if the mean square error of the current actual electricity consumption Qp is greater than the electricity threshold Delta Q, performing S4; and if the mean square error of the current actual electricity consumption Qp is not greater than the electricity threshold Delta Q, performing S5, wherein Delta Q=|Q-^|*Epsilon, Q-^ is the current theoretical electricity consumption, and Epsilon is a given setting value; S4, adding 1 to a counter Y; S5, resetting the counter Y to 0; and S6, after n periods T, when judging that Y exceeds a set maximum number Ymax, detecting that a relay protection device has a hidden fault. A hidden fault is detected by running electrical parameters. The detection rate of hidden faults is increased.

The present invention provides a separation method and system for transverse wave propagation in a crack. A collection coordinate system is rotated according to a setting angle, and if the rotation angle of the collection coordinate system is namely a fast wave polarization azimuth, the collection coordinate system is overlapped with a natural system of coordinates. If the rotation angle of the collection coordinate system is [Beta], the radial component R(t) after rotation is namely a slow wave component, and the transverse component T(t) is namely a fast wave component. Meanwhile, the energy ratio of the fast wave component and the slow wave component is an energy ratio of the radial component R(t) and the transverse component T(t) obtained through measurement, and the ratio should be equal to the tangent value of the crack direction azimuth. Through taking the relation mentioned above as a theoretical basis, it is analyzed whether the energy ratio of the radial component R(t) and the transverse component T(t) obtained through measurement after the collection coordinate system is rotated is equal to the tangent value of the rotation angle or not, and when the energy ratio of the radial component R(t) and the transverse component T(t) obtained through measurement after the collection coordinate system is rotated is equal to the tangent value of the rotation angle, the rotation angle is defined as the polarization azimuth of the fast wave. The separation method and system for transverse wave propagation in the crack are simple in the analysis operation process, fit into the current theory and have high accuracy.