Steam turbine control system applications have demanding requirements for governor valve actuators. High safety, durability, and positioning accuracy are the key features of steam turbine governing systems. In the event of a trip command from the control system and loss of power, the actuator must close the governor valve within 300- 500 ms to avoid turbine rotor over speeding. Diakont is a trusted supplier of industry-leading electric servo actuators and control systems for the energy industry. Diakont has extensive experience in supplying actuators and control modules for steam, gas and hydro turbine control valves for turbine manufacturers and automation companies worldwide. Diakont’s actuators deliver a direct replacement for hydraulic systems and provide a compact, more cost- effective, and safer solution. Electric Actuators for Steam Turbines ENGINEERED TO MOVE
Transcript
Steam turbine control system applications have demanding
requirements for governor valve actuators. High safety, durability, and
positioning accuracy are the key features of steam turbine governing
systems. In the event of a trip command from the control system and
loss of power, the actuator must close the governor valve within 300-
500 ms to avoid turbine rotor over speeding.
Diakont is a trusted supplier of industry-leading electric servo actuators
and control systems for the energy industry. Diakont has extensive
experience in supplying actuators and control modules for steam,
gas and hydro turbine control valves for turbine manufacturers and
automation companies worldwide. Diakont’s actuators deliver a direct
replacement for hydraulic systems and provide a compact, more cost-
effective, and safer solution.
Electric Actuators for Steam Turbines
EnginEErEd to MovE
State-of-the-art Solution
Diakont has successfully upgraded dozens of steam turbine control systems that incorporated dual-redundant EMAs, leading to impressive results. Diakont’s steam valve control systems have been shown to reduce the variance of full-load backpressure from ±4.25 PSI to ±0.5 PSI, increasing power output by 2.0 MWe per reactor with no corresponding change in thermal power output. Plus, Diakont actuators are able to complete a full linear stroke in less than 50 ms, which increases turbine safety and overspeed protection.
• Direct steam pilot valve actuation• Steam turbine control systems• Fuel valve control actuation
Peerles Performance in Steam Turbine Applications
Common Applications
State-of-the-art Solution
The fail-safe spring mechanism retracts the actuator output rod to a safe position at an extremely high speed in the event of trip command or power cutoff. The shock absorbers are mounted in the fail-safe mechanism flange to minimize the influence of shock load on the cone seating surface of the valve. Diakont electric servo actuators deliver additional reliability with redundant motors containing two independent stators with connections to independent junction boxes mounted on the actuators.
Fail-Safe Protection, Guaranteed
State-of-the-art Solution
Replacing electrohydraulic and hydraulic actuators in steam turbine control systems with Diakont electromechanical actuators delivers safety, maintenance and durability advantages:
1. Improved safety and reliability with a fail-safe spring mechanism and redundant motor
2. No oil issues: fully electric servo actuator design has no leakages from, pumps or hoses
3. Low maintenance with a long service life 4. High durability in severe environment conditions5. Smart digital control unit provides interface for simple
integration and troubleshooting
Turbine control systems based on electric servo actuators do not require any oil, hoses or pumps associated with hydraulic systems. This greatly reduces maintenance and operation costs. Additionally, this reduces fire hazards (especially for valves mounted on top of turbines), consequently reducing insurance prices.
Advantages and Benefits
Oil Free Turbine Control System
Electric Actuators for Steam Turbines
North AmericaDiakont Advanced Technologies 3853 Calle FortunadaSan Diego, CA 92123+1-858-551-5551 [email protected]
Europe Diakont
2 Uchitelskaja St.St. Petersburg, Russia 195274+7-812-324-6637 [email protected]
DiakontVia Achille Grandi nc.10/1252100 Arezzo, Italy+39-0575-250332 [email protected]
Electric Actuator with Fail-Safe Spring
Roller Screw
Dual Motor
EM Clutch
Closure Spring
Dual Sensors and Control Channels
Dual Motor
Roller Screw
Dual-Redundant EMA
Specifications
Electric Actuators for Steam Turbines
Pilot valve control actuator Steam control valve direct mounting actuator
Parameter Pilot valve control 4 500 lbf 20 kN 14 500 lbf 65 kN
Rated force 675 lbf (3 kN) Up to 5.9 in (Up to 150 mm)
Up to 10 in (Up to 250 mm)
Stroke 2 in (75 mm) 600 msec 600 msec
Motion time for full stroke 300 msec 2 in/sec (50 mm/sec)
Failsafe closing time for full stroke - 300 msec 300 msec
Positioning accuracy 0.0004” (0.01 mm)
Maintenance every 4 years
Lifetime 20 years
Safety integrity level Optional: SIL 2
Protection degree IP65 (optional: IP66)
Hazardous location standard Optional: ATEX Zone 2
Ambient Temperature -40°F to 185°F (-40°C to 85°C)
Mounting options Trunnion, rear clevis, front flange, custom mounting
Fail safe options • Fail safe spring and internal electromagnetic clutch• Dual-redundant control channel and electric motor• Manual over-ride hand wheel• Brake
In addition to developing rugged electric actuators for steam valve applications, Diakont has installed and commissioned entire control systems for numerous plants. Diakont provides both products and services for demanding power generation projects. Find out more by contacting an office near you.
Turbine Control Systems
North AmericaDiakont Advanced Technologies 3853 Calle FortunadaSan Diego, CA 92123+1-858-551-5551 [email protected]
Europe Diakont
2 Uchitelskaja St.St. Petersburg, Russia 195274+7-812-324-6637 [email protected]
DiakontVia Achille Grandi nc.10/1252100 Arezzo, Italy+39-0575-250332 [email protected]
