18-07-2011, 10:22 AM
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Governing Control system
• Speed Sensing :Mechanical (Fly ball type), Hydraulic (Pump), Electric (toothed Wheel pick up)
• MW Transducer for Power
• Processing : Hydro‐mechanical, Electrohydraulic, Digital Electro‐hydraulic
• Amplification: Hydraulic amplifiers in various stages
• Actuation: Hydraulic Servomotor
Control Requirements
• Start‐up: To control machine speed for proper synchronization
• Normal Operation: To Control MW and To participate in the control of system frequency
• Emergency: Load Rejection/Circuit Breaker Opening To restore speed deviation quickly without much transient over speed
Governing system: Technology
• Mechanical Hydraulic Control (MHC)
• Electro‐ Hydraulic Control (EHC)
Sensing, Processing, primary amplification using electronic circuitry
Transistor version (BHEL/ KWU Siemens Iskamatic modules)
• Digital Electro‐ Hydraulic Control (DEHC)
Microprocessor based