This device is applicable to the single-phase ground line selection for 3kV - 66kV isolated neutral system or neutral ground system through resistance or arc suppression coil, which can be extensively applied in the power supply system of power plant, substation and large-scale industrial enterprises, functioning as alarming the line and busbar single-phase grounding fault and tripping in single-phase grounding protection.
Compared with other products, this device is possessed of the following characteristics:
1) The device is a multiple CPU system with one IPC as the core; each piece of collecting card is equipped with an independent CPU so that to independently process all signals collected on each panel, which has effectively improved the data collection rate and data processing capacity of device.
2) The signal wave recording and playback processing techniques (with the national invention patents) are adopted, which have significantly improved the accuracy of line selection.
3) Follow-on IPC is adopted as the computing platform of the device, which is possessed of nice openness, compatibility and all functions of PC so that it may directly operate all kinds of application software of PC.
4) The chassis is all-steel industrial chassis which meets the "EIA" standard, in which the board card is installed vertically. The internal structure of chassis has been made of optimal design. Golden finger type interconnection of PCI bus in IPC has been abandoned while pinhole connector with 2mm density was adopted, through which its reliability and load capacity were significantly improved; meanwhile, the conventional mechanical structure of IPC was abandoned while European card structure was adopted, by which the input and output connecting lines were connected at the back so as to be convenient for wiring. At the time of installation and maintenance, the upper cover of chassis may be kept closed and this is convenient for the on-site use. Meanwhile, the heat dissipation conditions, anti-vibration and shock resistance abilities are improved and it meets the electromagnetic
compatibility requirement as well (this chassis has obtained the national patent for utility models).
5) Each piece of data collecting board is equipped with a separate high-performance ARM microprocessor, by which the number of frequency sampling point is up to 256 per period which is able to guarantee the accuracy while adopting transient state line selection.
6) Touch screen technique is adopted, mouse and keyboard which always break down are thus abandoned, and the man-machine interaction and operation are more convenient.
7) 8 in. colorful LCD is adopted to display the user interface, which is clear and aesthetic.
8) It is possessed of self-diagnostic function and may diagnose the board card when device is in failure.
9) The sensitivity of line selection is high and the minimum zero sequence current input of device may be 5 mA, which may help to guarantee accurate line selection with a small ground current (for example, high resistance ground).
10) It is possessed of message alarm function (when matching the message alarm module).
11) The device not only may carry out accurate line selection but also can exactly judge the ground phase (when matching the phase voltage collecting board).