The surrounding rock of a coal mine roof fractures with the excavation underground working face in mining. These mining-induced are connected and extended upward to form water inrush channels. A accident may occur when there is sufficiently large source. To elucidate formation mechanisms channel characteristics goafs, we performed case study No.18401 Panel Xiqu Coal Mine China determined whethe...

A novel control strategy is proposed in this paper for the rotor side converter (RSC) of doubly-fed induction generator (DFIG)-based wind power generation systems. It is supposed to enhance the low-voltage ride-through (LVRT) capability of DFIGs during great-level grid voltage dips. The strategy consists of a proportional-resonant (PR) controller and auxiliary PR controllers. The auxiliary cont...

Rock failure is the root cause of geological disasters such as slope failure, civil tunnel collapse, and water inrush in roadways mines. Accurate effective monitoring loaded rock process can provide reliable precursor information for inrushes underground engineering structures mines, tunnels, subways. The may affect safe efficient execution these structures. Therefore, it essential to predict e...

High-speed EMUs (electric multiple-units) frequently pass through the phase-separation zone during operation. Overvoltage generated operation of vehicle-mounted circuit breaker has a long duration and high waveform steepness, which accelerates service life equipment is likely to cause insulation failures. For above-mentioned problems, operating overvoltage characteristics high-speed EMU were ob...

The water inrush of the Shangjiawan karst tunnel is used to study evolution pattern precursor information in water-filled caves and further reveal matching mode information. three-dimensional numerical method FLAC3D was simulate process after damage a water-blocking rock mass structure cave obtain water-inrush caused by damage. results show that multifield response characteristic fracture follo...

Abstract An improved high voltage boost Z-source inverter topology is proposed to improve ability. Compared the conventional inverter, it can produce very with a short shoot-through duty ratio, stress on capacitors and inverter-bridge greatly reduced, has inherent limitation inrush current at startup. The addition of input capacitor an active switch allows in Z source network flow reverse direc...

The restrike of vacuum circuit breaker during the breaking process causes overvoltage and intensifies insulation deterioration high-voltage equipment. To solve this problem, aging test method characteristics are researched. A withstand voltage platform 40.5-kV was established to obtain effects contact spacing loop inrush currents on number restrike, wavefront steepness breakdown voltage, durati...