The Selection Design Of Non-Effectively Ground System In Coal6kV Power Supply System

Non-effectively grounded neutral point is usually adopted in coal6kV powersupply system. This approach can increase the reliability of electricity supply. In thispower supply system, three-phase voltage is still symmetry when single phase toground happened. Equipment can still be able to continue to run one or two hoursunder this fault conditions. Because of the increase of phrase voltage, supply securityis damaged. So the fault line selection is very important. Because of the weak faultinformation, it is a little difficult to find it. At the present time, the fault line is usuallyfalse dropped or miss dropped. The fault line selection of the non-effectively groundsystem is still needed continuous research.The S3C2440is used as the controller of the non-effectively grounded systemdevice. The S3C2440is a new generation of embedded controllers based on thearchitecture of the ARM920T. RISC architecture is used in the core. That structurenot only increases processing speed, but also simplifies the hardware complexity.Considering many signals needed to collect, multiple-way switch MAX308is used inthe device. Interference is an important factor influenced the precise line selection.The device increase it through decrease electromagnetic of the cable. Optoelectronicisolator is used to keeping the controller from the impact of the interference signal.The μC/OS-II is used as the kernel of the device. μC/OS-II is a portable, scalablekernel, and can be cured. This kernel can satisfy the device well both in real-time andstabilization. More important is that μC/OS-II has completely open source code. So itis very convenience to design the device.6-button input and touch-screen output mode is used as the human-computerinteraction.6-button is used to setting the parameter or polling fault information.Touch screen can display the condition of the cable, and monitoring the power systemat real-time. The touch screen can display the value of zero-sequence current andzero-sequence voltage in real time. And the fault which is detected can be recorded.