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Dual independent starting systems required on the main generator for a 3-tier power system?

asked Jul 9, 2014 in Mechanical by aodai (1,960 points)
Is dual independent starting systems required on the main generator for a 3-tier power system (emergency, essential and main)?

3 Answers

+1 vote
answered Jul 9, 2014 by sabdullayev (5,290 points) | selected Jul 9, 2014 by aodai
 
Best answer
A 3-tier power system (emergency, essential and main) dual independent starting systems is not required on the main.  If the essential and main generators services are combined, then dual independent starting systems are required on all main generators.
+1 vote
answered Jul 9, 2014 by josvanden (2,940 points)

Further information on the main generators for those who need to know

The main power generators should have sufficient capacity to supply power for all the Platform topsides, marine systems, accommodation and drilling package electrical loads, simultaneously. Main power generation system may be configured, installed and protected in such a way as to eliminate the need for an essential power generator.

All main power generators should be equipped for dual fuel operation. Fuel gas should be the primary fuel source and marine distillate fuel (all grades and all sulphur contents) should serve as the alternative. During initial drilling operational phase fuel gas will not be available.

Each generator should be equipped with automatic synchronizing capability to allow parallel operation for load sharing and power transfer between all units.  The control systems should include functions for auto-starting each unit, auto-synchronizing of all units and manual synchronizing under test conditions.

The main power generators should be designed and sized to satisfy the following requirements:

  1. Capacity to carry peak process, marine and accommodation loads with drilling rig at full capacity with one generator in reserve (N+1 configuration)
  2. Ability to start the largest motor with the remaining normal facility loads on-line without allowing the starting motor’s terminal voltage to dip below 80% of the nominal voltage.
  3. Ability to accommodate large step changes as may be anticipated for drilling loads.  
  4. Turndown capacity to carry peak load of the process, marine and accommodation with drilling rig warm stacked, without the use of resistive load banks.
  5. A vibration analysis should be performed to demonstrate sufficient dampening measures have been included to limit structural vibrations to an acceptable level.
  6. Main generator engines should be of the Low NOx combustion type.
+1 vote
answered Jul 9, 2014 by belmoreno (2,190 points)

Some information on Essential Power Generator and Emergency Power Generator:

Essential Power Generator

The essential generator(s), if required, should start automatically on main power failure.

The essential power generator should be diesel engine driven with a self-contained cooling system.  There should be two independent starting systems capable of minimum three start attempts each allowing minimum six consecutive starts. Air receivers for an air starting system should be sized for 6 consecutive starts.

Emergency Power Generator

The emergency power generator should start automatically on main power failure.

The emergency power generator should be diesel engine driven with a self-contained cooling system. There should be two independent starting systems capable of minimum three start attempts each allowing minimum six consecutive starts. Air receivers for an air starting system shall be sized for 6 consecutive starts.

The emergency generator and its associated switchboard should be installed in its own compartment in a safe area and should operate in parallel with or independent of other TLWP power systems. The emergency generator should be capable of black-start.

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