IGEA develops and launches transwitch units

The Institute of Mining Electrical Engineering and Automation developed and launched two 1250kVA transwitch unit modifications, one to feed and control a single double-drum shearer, a cooling plant, a compressor, a fan, and face lighting, and the other to feed and control a soft-start face conveyor, two chain-and-flight entry conveyors, a grinder, two pump plants, a winch, a welder, face emulsion injection pumps. Both options are intended for face No.12-n-3 at Belaruskali Mining Division No.3.

1250kVA transwitches with transformer’s neutral insulated are designed to convert 6kV into 1140VAC/3PH/50Hz (660V) to feed max. 15 consumers (as required by the customer), and to connect, control, and protect equipment in methane-hazard mines.

A transwitch consists of a transformer substation featuring a 1250kVA 6000V/1140V transformer and a compact station, sharing the same enclosure. To facilitate descending into a shaft and carrying to the operating site, the substation chassis may be disengaged from the compact station.

Each separate part shall not be longer than 4000mm. Transwitch circuits provide the following protection for every power branch:

  • Switch-over device interlock at connected branch resistance falling below 100Ω

  • Overload or short circuit protection, irregular current balance protection

  • Electric motor overheating prevention

  • Protection against ground circuit fault or resistance rise above 50Ω

  • Prevention of uncontrollability in case of remote control wire fault or interlocking

  • No-voltage protection

  • Unintended contactor enablement prevention upon momentary voltage jump to 1.5×Un

The transwitch control circuit is based on Simatic S1200 PLC with CPU 226 and Profibus DP network compatible EM 227 communication processor.

The transwitch features a substation operator’s panel to read and display power branch conditions, protection statuses, current loads, emergency shutdown causes, limit switch and sensor events with respective switch/sensor number.