Mining Switchgear and Distribution Equipment

By where they sit in the supply chain. High-voltage incoming and outgoing duty at an underground or surface substation, and large HV motor starting, use GKG-10(6) at 10 kV and 6 kV; power and lighting distribution downstream of the transformer low-voltage side uses GKD at 660 V and 380 V to 3200 A; terminal distribution in a chamber operating room uses PKD at 1140 V, 660 V and 380 V, 16 A to 630 A. A mine site commonly has all three stages.

GKD suits mine sites, locations free of firedamp and coal-dust explosion hazard, and comparable underground industrial workings of non-coal mines; PKD suits non-coal mines and other underground locations, and requires the chamber operating room to be free of dripping water and dust ingress. GKG-10(6) is also used beyond mining, in metro, wind, residential and industrial consumer substations. A working face with firedamp or coal-dust explosion hazard needs flameproof mining equipment, which is outside the scope of this page.

A mine supply system runs with an unearthed neutral. On a single phase-to-earth fault the line voltages are unchanged and the fault current is small, so overcurrent protection cannot see it and the fault has to be found from zero-sequence current and voltage; on the low-voltage side earth-leakage protection watches insulation to earth directly. That is why GKG-10(6) carries zero-sequence overcurrent and overvoltage, and GKD carries earth-leakage protection and undervoltage release.

For GKG-10(6) the rated short-circuit breaking current and the rated short-time withstand current are both 31.5 kA r.m.s., the rated short-circuit making current and the rated peak withstand current are both 80 kA peak, the rated short-circuit duration is 4 s and the rated number of short-circuit breaking operations is 30; the breaking and making operating sequence is O-0.3s-CO-180s-CO five times, O fourteen times and CO eleven times. Short-circuit figures for GKD and PKD follow the project system conditions.

GKG-10(6) and GKD are both IP54. The GKD enclosure is 2 mm cold-rolled steel plate in RAL 7035, fixed pattern, with cable entry from the trench. PKD is an indoor enclosed pattern with a frame of cold-rolled or stainless steel, bent and welded and treated against corrosion, IP21 and above and up to IP56, maintained from the front, with a warning on the front door panel against opening the cover while live.

GKG-10(6) is built to GB/T 12173 for general mining-duty electrical equipment and to GB 3906 among others; PKD follows GB/T 12173, GB 7251.1, GB 14048.1, GB 14048.2 and Q/FJ009. Where the destination market requires supply against the corresponding IEC standards, raise it during technical clarification so the applicable standards and document list can be stated in the quotation.

Yes. Switchgear is supplied as equipment, while the enclosure, panel arrangement, auxiliary systems and interface integration a mine substation needs are supplied by the prefabricated power module line, with the panels delivered as equipment inside the module. The boundary between underground roadway and surface substation, together with transport dimensions and lifting conditions, is settled during the scheme stage.

Four things at minimum: the class of mine and the installation position — surface substation, underground substation or chamber; the system voltage and neutral earthing arrangement; the rated current and circuit schedule for each stage; and the short-circuit capacity. To quote to contract level, add the protection configuration and communication interfaces, cable entry and exit directions, the altitude and temperature of the installation environment, and the destination market standards and document list.