NATIONAL ALUMINIUM COMPANY LIMITED - Rites

conditions for start and tripping of various drives shall be provided as per approved logic
diagrams.
A dedicated ed hardwired control panel / desk shall also be provided by the bidder at WT control
room to control and monitor electrical power distribution system.
Controls of all equipments of wagon tippler including conveyor’s all interlocks shall be PLC
based. The PLC system shall be latest version having dual redundant processor with HMI based
control station. There shall be two HMI control system with one operating station and other
an engineering station. The system shall be designed with 10% extra input/output pprovision.
Input/output of PLC(analog & digital) shall have at least 10% extra channel wired up to TB TBs in
the panels. A portable programming station (Laptop) with all the ladder logic/
programming/software shall be provided for engineering and troubleshooti
troubleshooting functions. The
system shall be capable of communicating with the existing PLC system of the CHP(The
existing PLC is of GE Fanuc make make- Model 90-30,CPU-370). 370). The vendor shall be responsible for
communicating and displaying the important parameters of wago wagon n tippler PLC system to the
existing CHP PLC through optical fibre cable. All electrical power distribution system shall be
controled and monitored through PLC.
PROTECTION SYSTEM
Protections for the different electrical equipment are enlisted below:
For Protection of LT T motor motor, comprehensive omprehensive numeric motor protection shall be provided in the
switchboard.
Laying of control and power cables including supply and laying of signal cables from motors to
switchboard shall be in the scope of Bidder.
Comprehensive ensive numeric motor protection including but not limited to the following:
• Instantaneous over current protection
• Differential protection (for rating above 1000 kW)
• Instantaneous time over current protection in two phases and definite time delayed over
current urrent alarm on the third phase
• Negative phase sequence protection
• Thermal overload taking -ve and +ve phase sequence into account
• Earth fault
• Locked rotor protection
• Winding temp monitoring and alarm for rating beyond 1000 kW
• Under voltage protectio protection
Microprocessor based numeric motor protection relay shall also have following facilities:
• Communication facility with open protocol like IEC/Modbus.
• Relay should store last five fault records (minimum) with date and time stamping.
• Relay should have no. o. of start menu for start inhibition.
• Relay should have facility for displaying three phase and neutral current
Technical Specification:Sec-6, Electrical
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