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Powerhouse types; plan with three units

Short answer

Powerhouse types are surface, semi-underground, and underground. A three-unit surface plant plan has three generator bays side by side with equal spacing, an erection bay at one end, control room along one side, and penstock branches with main inlet valves feeding each unit; draft tubes discharge to tailrace.

Mention the types of powerhouse. Draw the plan of a typical powerhouse having three units.

Types of powerhouse

  1. Surface (open-air) powerhouse: on the ground, at the dam toe or at the end of the penstock.
  2. Semi-underground powerhouse: substructure in a pit or shaft, superstructure at ground level.
  3. Underground (cavern) powerhouse: excavated in rock, connected by shaft and tunnels.

Plan of a typical powerhouse with three units

  <----------- Length ----------->
  +---------------------------------+  ^
  |  Unit 1   Unit 2   Unit 3  Erect| Breadth
  |  ( G )    ( G )    ( G )   bay  |  |
  |   ||       ||       ||    (EOT  |  |
  |  [MIV]    [MIV]    [MIV]  crane |  |
  +--||--------||-------||---------+  |
     Penstock branches        Control |  v
     (manifold)               room
  ------------------------------------
   Draft tubes -> tailrace ->

G = generator on a vertical shaft, MIV = main inlet valve. The three units sit side by side with equal spacing; the erection bay (with the loading area and the overhead travelling crane) is at one end; the control room, switchgear and offices lie along one side; the transformer yard is outside near the tailrace.

✓ Answer checked by Claude Opus 5.5 (high effort)

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