Pumped storage machines Reversible pump turbines, Ternary sets and Motor-generators 1 Cover picture Limberg II, Austria Harnessing the power of water with engineered reliability Generating energy from the power of water represents large amounts of clean, renewable energy. 71 percent of the earth’s surface is covered by water. The world’s hydropower potential amounts to 20 billion Mega Watt hours per year and only 25 percent of this has been developed so far. Hydropower is not only environmentally turing generators, turbines and associ- tomers and active in all major hydro- friendly, but also cost-effective. Hydro- ated control systems. As one of the power markets worldwide. power plants have the highest operating world’s leading provider for hydropower efficiency of all renewable generation products and services, Voith has an With more than 140 years’ experience systems. They are largely automated, amazing portfolio: We offer a wide in the field of hydropower and high and operating costs are relatively low. range of services, such as engineering, annual spending for research and devel- Hydroelectric power plants also play an manufacturing, project management opment, Voith is well-equipped to important role in water resource man- and commissioning. continue delivering excellence in hydro- agement, flood control, navigation, irri- As part of our international network power in the years to come. gation and in creating recreation areas. each Voith facility is equipped with con- Voith is a leading enterprise manufac- sistent best-in-class processes and tools. This network also ensures that we can meet special customized require- ments: from individual components to project planning, through project man- agement and plant maintenance. With branches and production facilities for electrical and hydraulic machines and components in Europe, Asia, North and South America we are close to our cus- 2 2 3 1 Hongrin Lemon, Switzerland 2 Upper reservoir Latschau, Rodund II, Austria 3 Rodund II, Austria Engineered reliability Competences and capabilities Is our promise to our customers. Our • Consulting, engineering, erection • Frequency converters, protection products and services are designed and commissioning systems, switchyards for all voltages, specifically for our customers’ needs. • System and plant assessments transformers Moreover, we follow our values and vi- • HyService – global, fast and effective • Power plant automation, control sions for sustainable hydropower solu- for modernization and rehabilitation centers for hydropower plants and tions with no compromise. of existing hydroelectric power plants cascades, including plant manage- • Complete equipment, installation ment and diagnostic systems and services for hydroelectric • Shut-off valves power plants • Integrated Management System to • Francis, Pelton, Kaplan, Bulb/Pit/ safeguard excellence and quality S-turbines, pump-turbines, standard and customized products • Storage pumps, radial, semi-axial and axial-flow pumps • Torque converters • Generators and motor-generators for constant and adjustable speed, excitation systems 3 Voith‘s pump storage plants work from the start Clean, flexible and renewable: Pumpstorage power plants offer a highly reliable technolo- gy which can perferctly level grid fluctuations and deliver energy immediately. In a world of energy increasingly dominated by wind and solar, pumpstorage power plants are in- dispensible. Over a period of decades Voith has developed a cutting-edge technology. In 1937, Voith developed the first large To meet the demanding requirements of In supplying equipment for pumped- pump-turbine, which operated both as a pumped storage plant, Voith applies a storage plants, Voith gained a lot of ex- a turbine for energy generation and, in distinctive quality management. Each perience in hydraulics over many years. the reverse direction, as a pump. component is manufactured with the A very large number of versatile Voith highest technical standard, i.e. shut-off designs have proven extremely satisfac- The first pumped storage station in valves, torque converters or clutches. tory in practical operation. In some cas- Germany was installed in 1908 in the With regard to the plant’s arrangement, es this experience covers many de- Voith research and development build- Voith always find technical solutions cades. It makes no difference whether ing, the Brunnenmühle in Heidenheim, which improve the readiness for opera- demand is for a reversible pump-turbine Germany. tion and a rapid transition from turbining or an optimally designed turbine and to pumping, and vice versa. pump. Nor is it of importance whether the pumpturbine is equipped with a fixed or an adjustable distributor or whether, in the case of separate turbine and pump, a clutch operable at stand- still, a starting turbine or a synchronising 1 4 Cross section of a Pump turbine/ Generator unit torque converter permitting extremely short changeover times is to be provided. Today, more than 200 Voith pumped storage units have been installed word- wide with a combined output of well over 24 000 MW. Whether a reversible pump-turbine, or a turbine and a pump combination, these machines have proven to be extremely durable, in many cases they have performed reliably for several decades. 1+2 Limberg II, Austria 3 Waldeck 3D model, Germany 2 3 5 Characteristics of reversible pump-turbines Advances in technology are constant, including the latest developments on variable-speed and wide head range applications. Reversible machine sets consist of a Variable-speed motor-generator and a reversible pump- With the use of variable speed technol- turbine that works either as a pump or ogy, by use of asynchronous motor- as a turbine depending on the direction generator or synchronous motor-gener- of rotation. Furthermore, a well-de- ator with frequency converter, the signed, compact power house save rotational speed of the pump-turbine equipment and civil costs. With a wide can be varied. Thus, the turbine operat- range of specific speeds, pump-tur- ing range can be extended, the pump bines can be installed at sites with capacity can be adjusted to using just heads from less than 50 to more than the currently available amount of energy. 800 m, and with unit capacities ranging This technology stabilize the grid effi- from less than 10 to over 500 MW. ciently. 1 Goldisthal, Germany 2 Limberg II, Austria 1 6 Selected pump-turbines: operation range in pump mode 3 Lewiston 1000 7 Coo I 12 Raccoon 14 Rodund II 29 43 36 49 21 Bath County 31 52 22 Coo II 47 42 53 3524 24 Estangento 21 14 39 50 27 25 Gabriel y Galan 7 51 45 12 27 Kühtai 44 34 38 22 29 Obrovac 48 31 Presenzano ] K = nq x H m 34 Palmiet [ 37 Q0.5 35 Bad Creek nq = n x H0.75 36 La Muela 100 37 Herdecke 38 Chiotas (4 stage) 39 Mingtan Pump head H 25 42 Shisanling K = 1000 43 Guangzhou II 44 Edolo (5 stage) 3 K = 800 45 Goldisthal (two variable speed) 47 Venda Nova 48 Tai An K = 200 K = 400 K = 600 49 Siah Bishe 50 Waldeck I 51 Limberg II 10 52 La Muela II 10 100 200 53 Ingula Specific speed nq Application range 1000 pump-turbine 100 Head (m) Setting getting deeper 10 1 10 100 1000 2 Output (MW) 7 Characteristics of storage pumps and torque converter Worldwide, Voith has earned a reputation as a major pump manufacture. Many pump storage plants work smoothly with Voith equipment. It’s the efficiency and longevity that matters when running pump storage plants. Our strength: reliable customized solutions. Pumps for storage applications are It transmits torque and/or power from This acceleration torque, which is ini- mainly of the radial-flow type. the motor-generator to the pump shaft tially very high, continuously decreases by being filled with process water. as secondary speed rises. When reach- Depending on the application condi- ing the synchronous speed, the con- tions the construction, can be a single- Start-up of the storage pump begins al- verter output torque corresponds to the or double-flow, single- and multi-stages ready during the filling process. As the pump priming torque. pressure level of the filling water rises, Torque converter the torque output by the converter in- Due to the soft interaction of these pro- The torque converter provides the most creases and thus accelerates the pump. cesses, the storage pump can be start- time efficient startup and shutdown of a ed up quickly. No load surges for the storage pump. Within seconds the stor- grid occur. age pump can be connected or sepa- rated from the shaft system. Hydraulic Torque Converter Application Range Radial-flow pumps 10000 1000 Radial-flow pumps Head (m) 100 0 1 10 100 1000 Output (MW) 8 Storage Pump, 3D model Ternary set Coupling to motor-generator Pelton turbine Ternary sets Ternary sets consist of a motor-generator, a separate turbine (typically Francis or Pel- ton) and a pump set. As two separate hy- draulic machines, the rotational direction of the motor-generator can be the same in both operational modes. This results in considerable commercial value for the power plant’s operation. For switching be- tween turbine and pump operation, the fol- lowing components can be provided: a clutch operable at standstill, a starting tur- bine or a synchronizing tourque converter. With the configuration of a ternary set the, so-called hydraulic short circuit within the machine set can be implemented. It offers Torque converter the best answer for a very fast grid re- sponse, being carried out with the torque Storage pump converter which allows fast change over between turbine and pump mode. Full reg- ulating capability exists in both, the turbine and the pump mode operation from 0% to 100% of the unit output. Hydraulic short circuit By using the hydraulic short circuit con- cept almost the full power range of the plant is available.