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Automated hydropowerThanks to instrumentation and control systems from Siemens, the test bench for hydraulic machines at the Karlsruhe University of Applied Sciences now represents state-of-the-art technology.

The user

What is now the Karlsruhe University of Applied Sciences was founded in 1878 as the “Grand Duchy of Baden College of Building”. Today, about 6 300 students are enrolled. In Germany overall, machine building takes second place in production, while in Baden-Württemberg it represents over 20 % of the economy.

At 125 years, mechanical engineering is the third oldest discipline at the Karlsruhe University of Applied Sciences. Almost 10 000 mechanical engineers have been educated there during its long history. In the ranking of all study courses at the Karlsruhe University of Applied Sciences, mechanical engineering takes second place.

The project

Due to increasing levels of automation, industry requires a growing number of mechanical engineering graduates from such universities. In order to adequately equip them for their professional careers, the Faculty of Mechanical Engineering and Mechatronics at Karlsruhe University of Applied Sciences has comprehensively modernized and completely automated its fluid mechanics laboratory under the leadership of Professor Eckhard Martens.

In the test facility for hydraulic machines, students learn the practical use of the machines installed in the test stand. This includes the structure, functionality, operating behavior and characteristics of variable-speed centrifugal pumps, Pelton turbines, Kaplan turbines and Francis turbines.

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Centrifugal pumps are the largest group within the cate-gory of flow machines. Their task is to raise, transport or circulate a fluid. The design of the impeller is determined from the different requirements in terms of volume flow, delivery height and fluid consistency.

The operating behavior of pumps is described in charac-teristic fields. In a practical test, the students record the characteristic line of a single-stage, close-coupled centrif-ugal pump of a radial design at a specific speed. The drive motor can be controlled variably by means of an attached frequency converter in speed controller mode from 1 500 to 3 000 1/min.

The objective of the test is to determine the key variables for the characteristic field of the pump: volume flow, spe-cific conveyance, flow rate, electrical power, efficiency, speed, net positive suction head and bypass volume flow. The machine can be regulated by means of throttling, speed control and a bypass. During the measuring exami-nation, cavitation occurs at a corresponding suction pres-sure. In order to be able to observe this phenomenon, a pipe connection made of Plexiglas has been fitted to the intake nozzle of the pump.

Fig. 1 Topology of the system, PCS 7 Kaplan turbine (insert with good resolution to display system topography).

In the tests on Pelton and Kaplan turbines, the students measure the variables of volume flow, pressure differen-tial, temperature, shaft torque and speed and then calcu-late the variables of hydraulic and mechanical energy, effi-ciency and running speed. The diagrams created show: specific nozzle work and drop over the volume flow, as well as shaft power, shaft torque, hydraulic power and efficiency, depending on the speed of rotation.

Developed from the various forerunners in impulse-type turbines, the Pelton turbine widens the field of hydraulic turbines in the direction of smaller volume flows, in other words, toward lower specific speeds. This type of turbine is used in storage and high-pressure power plants with drops of up to 1 800 m and volume flows of 60 m³/s. With impeller diameters of over 5 m, they can yield outputs in excess of 250 MW, while their efficiency is in the region of 92 % to 95 %. In the test, the net drop of the Pelton tur-bine is generated by means of a centrifugal pump set.

The test bench: centrifugal pumps and hydraulic turbines


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Fig. 2: Kaplan turbine, control cabinet with SIMATIC components and panel in background

The Kaplan turbine was the last of the three main types of turbine to be developed and extends the range of hydrau-lic turbines in the direction of higher flow rates with lower drops and high specific speeds. It is frequently used in run-of-river power plants with drops of up to 80 m and volume flows of 1 000 m³/s. With impeller diameters of over 8 m, they can yield outputs in excess of 100 MW, while the efficiency is in the region of 92 % to 95 %. The hydraulic energy necessary for the Kaplan turbine is real-ized in the fluid mechanics laboratory by means of a die-sel pump set.

In the fluid mechanics laboratory, the university also car-ries out commissioned studies for industry, i.e. for turbine manufacturers. Project work for redesigning and expand-ing the plant is often outsourced. For the near future, there are plans to incorporate a propeller pump test bench and replace the diesel engine with variable-speed electric motors.

Fig. 3: Transmitter valve block, orifi ce plate measurementLeft: 2x SITRANS P DSIII differential pressure transmitters for orifce platesRight: SITRANS FM MAG6000 transmitter for the MAG5100W fl ow meter

Fig. 4: P101, P102; SITRANS P DSIII Relative pressure measure-ments, nominal range 16 bar; before and after valveFour measurement points for determining average. The pressure measurements and the valve are used for regulating a specifi c pressure, for example, in order to apply a specifi ed (simulated) pressure level to the turbines.


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Following the modernization of the fluid mechanics labo-ratory for the Mechanical Engineering degree course at the Karlsruhe University of Applied Sciences, the course contents now also include the SIMATIC PCS 7 process con-trol system, digital communication by means of HART, PROFIBUS DP and PROFIBUS PA, and the comparison of various flow measurement methods. For example, in addi-tion to the existing orifice measurements, a vortex meter, a high-precision electromagnetic flow meter (MAG) and a hydrostatic differential pressure measurement have been installed. To allow the students to follow each individual step of the experiments, the SIMATIC WinCC visualization system from Siemens is displayed on a large screen by means of a computer projector.

The services provided by Siemens Industry Solutions, Germany, Southwest Region comprised the complete new installation, including supply of sensors, actuators, switch-gear, SIMATIC PCS 7, engineering and commissioning.

Installed measurement technology

The tests are evaluated and monitored on the basis of the measurement data of different flow metering methods. In addition, the measuring instruments can be compared with regard to their precision, as they are installed in four tubes arranged in parallel:

• Tube 1: Nominal diameter DN 100, SITRANS FX300 Vortex fl ow meter

• Tube 2: Nominal diameter DN 100, SITRANS FM MAG 5100W, followed by a SITRANS F O orifi ce plate measurement

• Tubes 3 and 4: Nominal diameter DN 200, SITRANS F O orifi ce plate measurement

The long straight inlet connectors in the test bench for hydraulic machines allow a good comparison of the differ-ent flow technologies. The result: with an accuracy of ± 0.20 % of the measured value, the MID SITRANS FM MAG 5100W with the MAG 6000i transmitter achieves the greatest accuracy, followed by the SITRANS FX300 Vortex flow meter with ± 0.6 % of the measured value. The ori-fice plate measurements are evaluated using the SITRANS P DSIII differential pressure measuring devices (nominal measurement range 1 600 mbar).

Installed automation technology with SIMATIC ET 200M

The SIMATIC ET 200M IM153-2 modular I/O system is par-ticularly suitable for application-specific and complex automation tasks. In the case of multi-channel applica-tions in the control cabinet, the SIMATIC ET 200M is the first choice.

Fig. 6: SITRANS P DSIII hydrostatic pressure measurement

Advantages of SIMATIC ET 200M

• Minimum wiring overheads• High plant availability• Hot swapping – replacement during operation

without interruption to power supply • Modular and redundant design possible• Channel-precise diagnostic functions

The field devices are connected by means of analog and digital I/O modules (4 ... 20 mA, HART or PROFIBUS PA). For the connection to PROFINET or PROFIBUS, various interface modules are available. These can be used not only in standard applications, but also in safety-related applications. Up to 12 multi-channel signal modules (e.g. 64 digital inputs) and function modules as well as SIMATIC S7-300 communications processors can be con-nected to the interface to the process. The SIMATIC ET 200M also supports modules with extended user data, such as HART modules with HART secondary variables.

The technology


© Siemens AG 2012

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Fig. 7: SITRANS FX300 VORTEX fl ow meter

Fig. 8: VORTEX larger.Foreground: Connection of the measuring orifi ce.

SIMATIC PDM – Tool with added value

SIMATIC PDM (Process Device Manager) is an integrated tool of STEP 7 and an integral component of the engineer-ing system of the SIMATIC PCS 7 process control system. The PCS 7 Maintenance Station enables all Siemens field devices, and those from many other suppliers, to be inte-grated directly into the control system quickly and easily. This solution permits a standardized and integrated con-figuration, parameter assignment, commissioning, diagnostics and maintenance of intelligent field devices and automation components. This not only increases safe-ty, but also minimizes investment, training and conse-quential costs.

Users can set, modify, manage, simulate and check the validity of field device data. In addition, selected process values, alarms and status signals can be observed online. The system also supports field device-specific functions such as simulation, measuring circuit test, characteristic input, calibration functions, documentation etc. All field device parameters can be modified online seamlessly and without stopping the PROFIBUS master.

User benefits

Following the successful completion of the project, the hydraulic test bench in the fluid mechanics laboratory now features the latest process control system and the most modern instrumentation in the entire university. The system is used for teaching across all faculties. With the very latest learning contents, the students are optimally equipped for their future working life.

Thanks to the integrated automation and the option of distributed access, the study supervisor can now control and monitor the experiments conveniently via a remote desktop, or from his office located two floors away, with-out having to be on site at all times. Further advantages of the integration: Installation/setup and parameter as-signment of the devices, as well as recording of measured values, can take place directly on the computer.

The SIMATIC PDM (Process Device Manager) tool permits the universal, manufacturer-independent configuration, parameter assignment, commissioning, diagnostics and maintenance of the intelligent field devices and automa-tion components.


© Siemens AG 2012

Siemens AGIndustry SectorSensors and CommunicationProcess Instrumentation76181 KARLSRUHEGERMANY

Subject to change without prior notice© 06/2012, Siemens AG

The information in this case study contains descriptions or characteristics of performance which in case of actual use do not always apply as described or which may change as a result of further development of the products. An obliga-tion to provide the respective characteristics shall only exist if expressly agreed in the terms of con-tract. Availability and technical specifications are subject to change without prior notice.All product designations may be trademarks or product names of Siemens AG or supplier companies whose use by third parties for their own purposes could violate the rights of the owners.

Statement

„The PCS 7 system is clearly structured and easy to operate. Since the commissioning, the automation system and measuring devices have been operating on a stable and error-free basis. At first glance, the system, which is distributed over two floors, appears very complex and quite confusing. The WinCC visualization system now enables us to demonstrate and explain the hydraulic test bench significantly more successfully to the students“

Till Hensgen, scientific assistant in the Fluid Mechanics department of the faculty of Machine Building and Mechatronics

Fig. 10: Measurement vessel with SITRANS P DSIII hydrostatic pressure measurement

Fig. 9 Valve block orifi ce plate measurement with SITRANS P DSIII differential pressure transmitter for measuring orifi ces


© Siemens AG 2012

environmental automated hydropower - siemens · test bench for hydraulic machines at the karlsruhe...

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