Abstract Water inrush is one of the most dangerous disasters in coal mining. Due to large-scale mining and complicated hydrogeological conditions, thousands deaths huge economic losses have been caused by water China. There are two main factors determining occurrence inrush: source water-conducting pathway. Research on formation mechanism pathway direction prevent control inrush, seepage rock m...

Power transformers in transmission network are utilized for increasing or decreasing the voltage level. Power Transformers fail to connect directly to the consumers that result in the less load fluctuations. Power transformer operation under any abnormal condition decreases the lifetime of the transformer. Power Transformer protection from inrush and internal fault is critical issue in power sy...

Mining operations in China are often threatened by frequent water inrushes from confined karst aquifers, We need to evaluate the risk from water-inrush from coal floors in order to have safe production in mines. water inrush risk assessment method based on fuzzy comprehensive evaluation is introduced in this paper. A secondary fuzzy comprehensive evaluation system is constructed to evaluate the...

We present a low power, on demand Parylene MEMS electrothermal valve. A novel Omega-shaped thermal resistive element requires low power (approximately mW) and enables rapid valve opening (approximately ms). Using both finite element analysis and valve opening experiments, a robust resistive element design for improved valve opening performance in water was obtained. In addition, a thermistor, a...

Although a typical PWM controller is well known for its good regulation capabilities, inrush current and overshoot voltage during start-up period as well as high switching losses at low loads are some of the major factors affecting its otherwise good performance. Therefore in this paper a simple Soft-start pulse skipping modulation (SSPSM) scheme implemented on a typical buck converter is prese...

This paper proposes a three phase transformerless AC/AC converter which can perform both buck and boost operations based on the voltage requirements. This AC/AC converter is mainly proposed for the three phase induction motor drives with the intention to reduce the high inrush current of the conventional motor used in industrial applications. The merits of the proposed AC/AC converter can be un...

Many industrial and commercial sensitive loads are subject to the voltage sags and interruptions. The static transfer switch (STS) based on the thyristors is applied to improve the power quality and reliability. However, the transfer will result in severe inrush current in the load transformer, because of the DC component in the magnetic flux generated in the transfer process. The inrush curren...