Pelton turbine with at least four nozzles and a feed system and method for modernising an existing hydroelectric power plant

Abstract

A Pelton turbine comprising a rotor with a horizontal axis of rotation and a supply system with at least four nozzles which surround the rotor in a uniformly distributed manner in the circumferential direction, and wherein the supply system comprises a first arm (1) and a second arm (2), and wherein the first arm (1) is connected to at least two adjacent nozzles, and wherein the second arm (2) is connected to the remaining nozzles, and wherein each arm (1, 2) comprises a strand which partially wraps around the rotor, from which at least one first pipe branches off to a first nozzle, and wherein a further nozzle forms the end of the strand, and wherein each arm (1, 2) comprises a bend (1.1, 2.1) and a connecting pipe section (1.2, 2.2), and wherein the axes of the connecting pipe sections (1.2, 2.2) are aligned parallel to the axis of rotation of the rotor, and wherein each connecting pipe section (1.2, 2.2) is connected to the turbine via the associated bend (1.1, 2.1) is connected to the corresponding strand.

Description

[0001] The invention relates to a Pelton turbine with at least four nozzles and with a supply system for the driving water and a method for modernizing an existing hydroelectric power plant with Pelton turbines.

[0002] Pelton turbines according to the invention with four, five, or six nozzles are particularly advantageous. Pelton turbines according to the invention with an even number of nozzles are used in the modernization process according to the invention.

[0003] The invention is described using the particularly advantageous six-nozzle embodiment. Transferring the inventive concept to embodiments with a different number of nozzles is easily possible for those skilled in the art.

[0004] 6-nozzle Pelton turbines with a feed system are known from the prior art. For example, US 2 965 764 A discloses a 6-nozzle Pelton turbine with a feed system that extends almost 360° around the turbine runner. Although this design requires a lot of space, it is usually used in 6-nozzle Pelton turbines with a vertical axis of rotation. A 6-nozzle Pelton turbine with a horizontal axis of rotation is disclosed in EP 2 035 689 B1. The cost-effective feed system consists of a central distribution pipe from which six feed lines branch off. The central distribution pipe runs in the axial direction of the turbine, and the feed lines branch off from the central distribution pipe in an oblique-axial direction, evenly distributed in the circumferential direction.

[0005] When modernizing existing hydroelectric power plants that incorporate Pelton turbines, the challenge often arises to combine several of the existing turbines with larger or more powerful units in order to reduce maintenance costs. This requires consolidating the flow rates by merging the individual inlets of the existing turbines.

[0006] The object of the invention is to provide a Pelton turbine with at least four nozzles, a horizontal rotation axis, and an alternative feed system, which has a compact design. Furthermore, the turbine according to the invention is highly suitable for modernizing existing hydropower plants that incorporate Pelton turbines, since the inventive design of the feed system enables efficient and cost-effective merging of the existing inlets.

[0007] The object is achieved according to the invention by an embodiment according to the independent claims. Further advantageous embodiments of the present invention can be found in the subclaims.

[0008] The invention is explained below with reference to the figures. The figures show in detail: Fig. 1: Inventive Pelton turbine in side view Fig. 2: Inventive Pelton turbine in plan view Fig. 3: Hydroelectric power plant before modernization Fig. 4: Hydropower plant after modernization Fig. 5: Hydropower plant after modernization Fig. 6: Hydroelectric power plant before modernization Fig. 7: Hydroelectric power plant after modernization

[0009] Fig. Figure 1 shows a side view of a 6-nozzle Pelton turbine according to the invention. The turbine comprises a runner with a horizontal axis of rotation and a supply system with six nozzles evenly distributed circumferentially around the runner. The runner comprises a plurality of buckets, which are pressurized with motive water through the nozzles during operation. The supply system comprises two arms, a first arm designated 1 and a second arm designated 2. The first arm is connected to three adjacent nozzles, and the second arm is connected to the remaining nozzles. Each arm comprises a branch partially encircling the runner, from which two pipes branch off successively to a nozzle each, with a third nozzle forming the end of the branch.

[0010] In a 4-nozzle design, each strand would comprise two nozzles. In a 5-nozzle design, one of the strands would comprise two nozzles and the other strand would comprise three. In designs with an odd number of nozzles, the arms differ at least in that the number of nozzles in the two arms differs by one, meaning that in each case, the nozzles are distributed as evenly as possible between the two arms.

[0011] Fig. Figure 2 shows a plan view of the Pelton turbine according to the invention. The impeller is arranged in a turbine casing, which is designated by 3. In Fig. 1, the turbine housing is not shown for the sake of clarity. The runner is also connected to a generator, designated 4. The dashed line sections running centrally at the top and bottom indicate the collinear axes of rotation of the runner and the generator. Each arm comprises a bend, designated 1.1 and 2.1, respectively, and a connecting pipe section, designated 1.2 and 2.2, respectively. The axes of the connecting pipe sections 1.2 and 2.2 are indicated by dashed lines. The axes of the connecting pipe sections 1.2 and 2.2 are aligned parallel to the axis of rotation of the runner. The connecting pipe sections 1.2 and 2.2 are connected to the associated branches via the bends 1.1 and 2.1. The bends 1.1 and 2.1 therefore cause a 90° deflection of the flow direction in the respective arm (from a direction parallel to the axis to a direction tangential to the axis).

[0012] In the Fig. 1 and Fig. In the embodiment shown in Figure 2, the connecting pipe sections 1.2 and 2.2 are located on the same side of the impeller. This has the advantage of a compact turbine design. However, the connecting pipe sections 1.2 and 2.2 can also be distributed on both sides of the impeller, ie, for example, the connecting pipe section 1.2 could be located in Fig. 2 can also be arranged above the runner, with its opening facing upwards. This can be advantageous if the turbine according to the invention is used to modernize a hydroelectric power plant in which the supply lines to two adjacent existing turbines run toward them from opposite directions. The two sides of the runner are separated from each other by a plane defined by the center lines of the runner buckets.

[0013] In the embodiment according to Fig. 2, the generator 4 is arranged on the side of the impeller where the connecting pipe sections 1.2 and 2.2 are also located. This also results in a very compact design. The generator 4 could also be arranged on the other side. This can be advantageous if the turbine according to the invention is part of a tandem unit, i.e., if two turbines according to the invention are connected to one generator. The generator 4 is then arranged between the two turbines, and the four connecting pipe sections run outward from the generator.

[0014] In the Fig. 1 and Fig. In the embodiment shown in Figure 2, the two arms 1 and 2 are constructed identically, which is advantageous for cost-effective turbine production. This identical construction results in the rotation axis being positioned centrally between the axes of the connecting pipe sections 1.2 and 2.2 (all of these axes then also lie in one plane). This is also advantageous if the turbine according to the invention is used to modernize an existing power plant. The two arms can only be constructed identically in embodiments with an even number of nozzles.

[0015] In the following, the inventive modernization process of an existing hydroelectric power plant is described on the basis of the Fig. 3 and Fig. 4. The configuration of the existing hydroelectric power plant and the Pelton turbines according to the invention used for the modernization shown in these figures was chosen because it offers a particularly large number of advantages. Based on the description of this configuration, the person skilled in the art can easily transfer the modernization method according to the invention to other configurations.

[0016] Fig. Figure 3 shows a plan view of an existing hydroelectric power plant prior to modernization. The hydroelectric power plant comprises a total of four Pelton turbines, with two Pelton turbines and a generator forming a tandem unit. One of the two generators is labeled 7. The associated Pelton turbines are labeled 6.1 and 6.2. The existing Pelton turbines are two-nozzle variants with a horizontal axis of rotation. The Pelton turbines are supplied with water via a common penstock, which is shown in the lower part of the figure. An inlet line for each Pelton turbine branches off from the penstock. A shut-off device is located in each inlet line. One of the shut-off devices is labeled 5.The dashed horizontal line runs at the end of the supply lines and indicates the interface between the recycled parts and those parts that will be replaced during the modernization. The . Fig. 3 parts located below the dashed line are reused.

[0017] Fig. 4 shows the hydroelectric power plant Fig. 3 after the modernization. Two existing Pelton turbines belonging to a tandem unit were replaced by a new Pelton turbine according to the invention. The connecting pipe sections of the new inventive Pelton turbines were connected to the corresponding inlet lines. Since the inlet lines belonging to two adjacent existing Pelton turbines run parallel to each other, the connection to the connecting pipe sections could be made without any special adaptation. The lateral distance between the connecting pipe sections in a Pelton turbine according to the invention can be varied by adjusting the pipe segments of arms 1 and 2, which are arranged between the first nozzle branch and the bends. Certain limits are set for small values ​​of this distance.

[0018] Since all shut-off devices are retained during the modernization, the penstock does not need to be drained. Instead, the other tandem unit can continue to operate while one tandem unit is dismantled. This minimizes downtime during the modernization. In the example described, two 2-nozzle Pelton turbines are replaced by one 6-nozzle Pelton turbine. Although the given flow is now only processed by one impeller, the number of nozzles can increase the power density and improve part-load performance by reducing ventilation losses. Since machines with a larger number of nozzles operate at higher speeds, a compact design is also achieved.A further advantage is that the existing underwater channels can be connected to form a channel using the existing generator pit, through which the drainage of the new turbine according to the invention can take place.

[0019] The modernization will use Pelton turbines with an even number of nozzles.

[0020] The application of the modernization method according to the invention is not limited to hydropower plants with tandem units. Two separate Pelton turbines, each with an associated generator, can equally well be replaced by a single Pelton turbine according to the invention with a single generator.

[0021] In the following, further configurations for a modernization according to the invention are briefly described as examples.

[0022] A particularly advantageous embodiment of the modernization method according to the invention can be carried out on an existing power plant, which is a reflection of Fig. 3 at the top of the figure. This means that the existing power plant comprises two rows of tandem units, which are supplied with hydropower by two penstocks arranged on either side. During the modernization, two of the existing tandem units will be replaced by a new tandem unit with two Pelton turbines according to the invention. Fig. Figure 5 shows the hydroelectric power plant after modernization.

[0023] Fig. Figure 6 shows another hydroelectric power plant before modernization. The power plant comprises four separate Pelton turbines, each with a generator. The turbines are fed by two laterally arranged penstocks. Fig. 7 shows the power plant Fig. 6 after modernization. The modernized power plant comprises two Pelton turbines according to the invention, with the connecting pipe sections arranged on different sides of the corresponding runners.

[0024] Finally, it should be emphasized again that the Pelton turbines according to the invention can not only be used in the modernization of existing hydroelectric power plants, but can also be advantageously implemented in new plants due to their compact design. Fig. 4, Fig. 5 and Fig. The embodiments shown in Figure 7 could also be implemented as new systems. For new systems, designs with an odd number of nozzles can also be advantageously used. List of reference symbols 1 First arm 1.1 Manifold 1.2 Connecting pipe piece 2 Second arm 2.1 Manifold 2.2 Connecting pipe section 3 turbine housings 4 Generator 5 Shut-off device 6.1 Pelton Turbine 6.2 Pelton Turbine 7 Generator

Claims

[1] Pelton turbine comprising a rotor with a horizontal axis of rotation and a feed system with at least four nozzles which surround the rotor in a uniformly distributed circumferential direction, characterized by in that the feed system comprises a first arm (1) and a second arm (2), and wherein the first arm (1) is connected to at least two adjacent nozzles, and wherein the second arm (2) is connected to the remaining nozzles, and wherein each arm (1, 2) comprises a strand partially wrapping around the impeller, from which at least one first pipe branches off to a first nozzle, and wherein a further nozzle forms the end of the strand, and wherein each arm (1, 2) comprises a bend (1.1, 2.1) and a connecting pipe section (1.2, 2.2), and wherein the axes of the connecting pipe sections (1.2, 2.2) are aligned parallel to the axis of rotation of the impeller, and wherein each connecting pipe section (1.2, 2.2) is connected to the associated strand via the associated bend (1.1, 2.1). [2] Pelton turbine according to claim 1, wherein the Pelton turbine comprises six nozzles, and wherein the first arm (1) is connected to three adjacent nozzles, and wherein from each string a first pipe branches off successively to a first nozzle and a second pipe to a second nozzle, and wherein a third nozzle forms the end of the string. [3] Pelton turbine according to claim 1 or 2, wherein the one connecting pipe section (1.2) is arranged on a first side of the impeller, and wherein the other connecting pipe section (2.2) is arranged on the same side of the impeller. [4] Pelton turbine according to one of claims 1 to 3, wherein the number of nozzles is even and the two arms (1, 2) are identically constructed. [5] Pelton turbine according to one of claims 3 or 4, wherein that side of the impeller on which the connecting pipe pieces (1.2, 2.2) are arranged can be connected to a generator (4). [6] Pelton turbine according to one of claims 3 or 4, wherein that side of the impeller on which the connecting pipe pieces (1.2, 2.2) are not arranged is connectable to a generator (4), and wherein the Pelton turbine is intended to form part of a tandem unit. [7] Pelton turbine according to claim 1 or 2, wherein the one connecting pipe section (1.2) is arranged on a first side of the impeller, and wherein the other connecting pipe section (2.2) is arranged on the other side of the impeller. [8] Method for modernising an existing hydroelectric power plant with at least two Pelton turbines (6.1, 6.2), wherein the hydroelectric power plant comprises a first existing inlet line for a first existing Pelton turbine (6.1), and wherein the hydroelectric power plant comprises a second existing inlet line for a second existing Pelton turbine (6.2), and wherein the two existing Pelton turbines (6.1, 6.2) are replaced by a new Pelton turbine with an even number of nozzles according to one of the preceding claims, and wherein a first connecting pipe section (1.2) of the new Pelton turbine is connected to the first existing inlet line, and wherein a second connecting pipe section (2.2) of the new Pelton turbine is connected to the second existing inlet line.

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