1. Product Overview
Smr-dfs-s station type distributed small current grounding line selection device does not need to measure the zero sequence voltage and zero sequence current signal, only needs to collect the phase current and phase voltage signal of the line to carry out single-phase grounding fault line selection, and does not rely on communication and other line information to realize local grounding fault line selection, positioning and rapid isolation. It is applicable to the local research and judgment of single-phase grounding fault of single outgoing line in substation or switching station of small current grounding system (ungrounded, arc suppression grounding and low resistance).
2. Product Features
Line selection function: generally, it only collects three-phase current and three-phase voltage, and it can complete line selection function without collecting zero sequence voltage and zero sequence current; In extreme cases, only three-phase current needs to be collected to complete line selection.
Short circuit identification function: when a short circuit fault occurs in the downstream of the detection point, it can accurately judge the short circuit path and automatically return after the fault disappears.
Trip function: the trip function is realized by connecting to the protection trip circuit. The on / off and trip delay of the device can be set.
Phase judgment function: when the system has grounding fault, it can accurately judge the grounding fault phase.
Local ground fault identification: the device can select single-phase ground fault line without measuring zero sequence voltage and zero sequence current signal, and can identify the ground fault of the line completely without relying on communication and other line information;
Accurate grounding fault line selection: relying on the domestic leading and original high-precision open phase current transformer technology, it can accurately use the three-phase current to synthesize high-precision zero sequence current (meeting 0.2S level) signal, and the station distributed line selection device can accurately identify the fault current ≥ 1a, It can reliably solve the local identification of high resistance grounding fault within 5K and zero crossing grounding fault without any transient process.
Flexible installation: each outgoing line is equipped with a set of equipment, namely distributed small current grounding line selection device. At the same time, it can be flexibly installed in batches according to the user's needs (which outgoing line is most prone to failure is preferentially installed on which outgoing line) and power outage arrangement (which outgoing line is arranged to be installed on which outgoing line for power outage repair first), and put into operation as soon as it is installed. The intelligent wireless communication mode is adopted between the distributed small current equipment and the main station equipment (remote communication gateway) in the station, which is convenient for on-site layout. The distributed small current equipment can be flexibly added into the system, without complex secondary line long line layout, and the cabinet is arranged nearby, which is convenient for construction.
