Electrohydraulic Drive System EHC-A

Electrohydraulic Drive System EHC-A

HYDAC Denmark HYDAC Poland HYDAC Brazil HYDAC India HYDAC China HYDAC USA HYDAC France HYDAC Germany Your Professional Partner for Electrohydraulic Drive Systems. With over 8,000 employees worldwide, HYDAC is one of the leading suppliers of fluid technology, hydraulic and electronic equipment. Our wide range of products, combined with our expertise in development, manufacturing, sales and service enables the thermal power industry worldwide to overcome the most diverse challenges with the aid of electrohydraulic drive systems. Global yet local. With over 50 overseas subsidiaries and more than 500 sales and service partners, HYDAC is your reliable partner worldwide. System solutions. One supplier. One contact. Wherever you need us, we are there to help you find the most effective solution for almost every application, from components to a complete system. Worldwide specifications and approvals. 2

Electrohydraulic Drive System EHC-A Functional safety in the water/steam circuit Process technology systems in the power plant must be operated safely because they pose a considerable potential hazard to human health and the environment and can cause damage. When developing appropriate protection systems, the focus must centre on parts of the control which are relevant to the safety of the machine. This is particularly relevant for control valves and their drives which have an overlaid safety function. The requirement for a control valve with a safety function and the device for monitoring the steam condition are, amongst other things, described in EN ISO 4126-5 and TRD421. The objective of the regulations is to detect a failure safely and to trigger a safety function. Description and advantages By using electrohydraulic systems, movements can be controlled. Compared with other drive types, electrohydraulic drives are differentiated by: High power density Low moments of inertia High dynamic response Compact size High degree of accuracy High level of reliability and long life Integrated linear measurement Applications Water/steam circuit Minimum flow control valve Feed water flow control valve Level control valve Back-up steam control valve HD injection valve IS injection valve HP bypass station HP bypass station IS relief valve LP bypass station Condensate control valve Turbine shut-off valve Turbine inlet valve LP bypass station In the water/steam circuit, pressure and temperature are finely adjusted and controlled using steam valves to correspond with the requirements of the systems further downstream, for example the turbine. By using hydraulic actuators high quality control and the maximum dynamic response are achieved. 3 Note: The information in this brochure relates to the operating conditions and applications described. For applications or operating conditions not described, please contact the relevant technical department. Subject to technical modifications. Slam-shut valve to protect against turbine overspeed

Preferred ranges Electrohydraulic Drive System EHC-A 50 63 80 100 Piston diameter D mm 50 63 80 100 Rod diameter d mm 25 28 36 45 Reduced piston diameter Dr mm 25 28 36 45 Cylinder stroke max. hz mm 50 63 80 100 Maximum pressure Pmax bar 250 250 250 250 Working pressure min. Pa bar 100 100 100 100 Static force from Working pressure min. FkOil (Pa) kn 14.7 25.0 40.1 62.6 Spring force min. F1 kn 7.4 12.5 20.0 31.3 Spring force max. F2 kn 11.0 18.8 30.1 47.0 Counterforce from system (75 % of F1) FSteam kn 5.5 9.4 15.0 23.5 Model code Electro Hydraulic Control Actuator Piston diameter XXX = mm Cylinder type S = Double rod cylinder (synchronizing) D = Single rod cylinder (differential) Type of spring D = Disc spring S = Spiral spring W = Without spring Direction of movementbwith spring assistance E = Extension R = Retraction EHC-A XXX X X X X Measurement technology W = Linear measurement system O = Optical/mechanical position indicator E = Limit switch P = Pressure measurement ( X ) = Redundant version possible 4

125 140 160 180 200 220 250 125 140 160 180 200 220 250 50 56 63 70 80 90 100 50 56 63 70 80 90 100 125 140 160 180 200 220 250 250 250 250 250 250 250 250 100 100 100 100 100 100 100 103.1 129.3 169.9 216.0 263.9 316.5 412.3 51.5 64.7 84.9 108.0 131.9 158.3 206.2 77.3 97.0 127.4 162.0 197.9 237.4 309.3 38.7 48.5 63.7 81.0 99.0 118.7 154.6 Technical Details Nominal pressure Operating fluids 160-250 bar ISO VG 32, ISO VG 46, Mineral oil to DIN 51 524, HFD-U HFD-R fire-resistant ISO 6743-4 others on request Temperature range of environment -5 C to +60 C, option -20 C to +80 C Operating temperature optimum +40 to +50 C Atmosphere Relative humidity up to 90 % Electrical data Supply voltage Dusty industrial environment, potentially explosive according to ATEX Directive (optional) 24 V DC, 230 V 50/60 Hz AC Voltage tolerance up to +15 % / -15 % Nominal current of coil Protection class Nominal current for positioning module Target position 0-100 % Actual position 0-100 % Positioning 0.8 A for 24 V DC (TRD system), 1.2 A for 24 V DC (standard coil) IP65 (Standard), ExII 2G Eex d IIC T4 (Atex) < 100 ma 4-20 ma 4-20 ma Positioning accuracy < 1 % Repeatability < 0.1 % Hysteresis < 0.1 % Actuating times Control operation Controlled Open / Close Safety stroke Open / Close 3 s - 60 s 1 s - 30 s 0.1 s - 1.5 s 5

Function diagram Control module EHC-D Hydraulic control EHC-S Hydraulic cylinder EHC-A Item Control function Control adaption w Input scaling Feedback A B x Input scaling Enable Start Hand + Hand - Control program Ready InPos P T NG6 Option: Safety and Function Module The modular electrohydraulic safety controls EHC-S from HYDAC satisfy the requirements of IEC 61508 and IEC 61511. EHC-S 1oo1 Applications in so-called enable circuits EHC-M Function module for steam valve controls EHC-S 1oo3 For ball valve applications in water/steam circuits EHC-U Power unit for oil supply in turbine controls Other versions on request. EHC-S 2oo3 Applications in turbine controls and on process safety valves 6

System Expertise with First-Rate Service Network: Local Availability Worldwide. User accessories HYDAC offers a comprehensive and proven range of condition monitoring products, components and systems designed for fluid conditioning and monitoring as well as for technical cleanliness of components. Condition monitoring Contamination sensor CS 2000 To monitor the essential fluid parameters in turbine hydraulics online, HYDAC has developed an extensive fluid monitoring range which makes a significant contribution to the safe operation of both the turbine hydraulics and lubrication. FAM dewatering unit On lubrication oil systems of steam turbines, particularly high levels of unwelcome process steam and water enter the oil circuit. This results in substantially increased fluid ageing and limited lubrication. By using FAM dewatering and filtration units continuously during system operation, integrated conditioning of the lubrication media is assured. Degassing unit IXU When hydraulic fluids based on phosphate esters are used, it is essential to condition the fluids (also during system operation). HYDAC offers an extensive range of ionexchange conditioning products (IXU). NEW Stat-Free filter elements The operation of modern power plant hydraulics and lubrication systems with zinc-free fluids gives rise to risks of electrostatic charging of the oils (especially via the filter elements). Uncontrollable voltage flashovers, formation of sludge and varnish as well as rapid oil ageing are the result. HYDAC Stat-Free filter element technology prevents these unwelcome side-effects and increases the safety of the system for the operator. 7

Cooling Systems 5.700 Electronics 180.000 Accessories 61.000 Compact Hydraulics 53.000 Filter Systems 79.000 Process Technology 77.000 Filtration Technology 70.000 Accumulator Technology 30.000 Global Presence. Local Expertise. www.hydac.com HYDAC Headquarters HYDAC Companies HYDAC Sales and Service Partners Head Office HYDAC SYSTEM GMBH Industriegebiet 66280 Sulzbach/Saar Germany Tel.: +49 6897 509-01 Fax: +49 6897 509-577 E-mail: info@hydac.com Internet: www.hydac.com