Pelton water turbine control device and pelton water turbine control method

Abstract

To smoothly execute a switching operation for changing the number of nozzles to be used during operation in a Pelton water turbine.SOLUTION: A Pelton water turbine control device performs first water turbine operation by injecting water from a first nozzle, and second water turbine operation by injecting water from the first nozzle and a second nozzle different from the first nozzle. When performing a first switching operation to switch from the first water turbine operation to the second water turbine operation, the Pelton water turbine control device reduces, when power output by a generator decreases during the first switching operation, a rate at which the needle opening of the first nozzle is reduced compared to before the decrease in the power output by the generator, while increasing a deflector opening compared to before the decrease in the power output by the generator, and increases a rate at which the needle opening of the second nozzle is increased compared to before the decrease in the power output by the generator.SELECTED DRAWING: Figure 5A

Description

Technical Field

[0001] Embodiments of the present invention relate to a Pelton turbine control device and a Pelton turbine control method.

Background Art

[0002] A Pelton turbine installed in a hydroelectric power plant or the like is configured to drive a generator by injecting water from a nozzle onto a runner and rotating the runner.

[0003] In a Pelton turbine, a runner has a plurality of buckets arranged in the rotational direction. The nozzle is configured to adjust the flow rate of water injected into the plurality of buckets by varying the needle opening degree with a needle valve. Further, the Pelton turbine includes a deflector, and is configured such that the flow of water acting on the plurality of buckets from the nozzle changes by varying the deflector opening degree of the deflector.

[0004] There are a plurality of nozzles and deflectors, and one deflector is installed corresponding to one nozzle. The Pelton turbine operates by switching the number of nozzles that inject water to rotate the runner according to the output of the generator.

[0005] In a Pelton turbine, for example, there are 4 nozzles, and it performs a 2N operation in which the runner is rotated by injecting water from 2 of the 4 nozzles, and a 4N operation in which the runner is rotated by injecting water from all 4 nozzles. In the Pelton turbine, when increasing the output of the generator, a switching operation from the 2N operation to the 4N operation is executed. Also, when decreasing the output of the generator, a switching operation from the 4N operation to the 2N operation is executed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] FIG. 7 is a diagram showing a switching operation for switching from 2N operation to 4N operation in a Pelton water turbine of the related art. FIG. 8 is a diagram showing a switching operation for switching from 4N operation to 2N operation in a Pelton water turbine of the related art. In FIGS. 7 and 8, the transitions of the deflector opening command DFR and the needle opening command NVR are shown in time series.

[0008] In FIGS. 7 and 8, the deflector opening command DFR indicates the deflector opening of the four deflectors used when performing 2N operation and 4N operation.

[0009] Also, in FIGS. 7 and 8, as the needle opening command NVR, the needle opening command NVR1 and the needle opening command NVR4 are shown. The needle opening command NVR1 is the needle opening of the two nozzles N1 and N2 (first nozzles) that inject water to rotate the runner in 2N operation and 4N operation among the four nozzles N1 to N4. The needle opening command NVR4 is the needle opening of the other two nozzles N3 and N4 (second nozzles) that do not inject water in 2N operation but inject water to rotate the runner in 4N operation among the four nozzles N1 to N4.

[0010] [1]Switching operation from 2N operation to 4N operation (first switching operation) As shown in FIG. 7, when performing the switching operation for switching from 2N operation to 4N operation, the deflector opening command DFR is decreased compared to before performing this switching operation (during the execution of 2N operation). For example, the deflector opening command DFR is decreased from 100% to DFRa (%) (DFRa < 100) at the time point t1 when the switching operation starts.

[0011] Accordingly, from the time point t1 when the switching operation starts, as the needle opening degree command NVR1 of the nozzles N1 and N2 decreases at a constant rate (K1a), the needle opening degree command NVR4 of the nozzles N3 and N4 increases at a constant rate (K4a). As a result, at the time point t2, the needle opening degree command NVR1 of the nozzles N1 and N2 and the needle opening degree command NVR4 of the nozzles N3 and N4 reach the same state. For example, the needle opening degree command NVR1 of the nozzles N1 and N2 decreases from 100% to NVRa (%) (0 < NVRa < 100) between the time point t1 and the time point t2. In contrast, the needle opening degree command NVR4 of the nozzles N3 and N4 increases from 0% to NVRa (%) between the time point t1 and the time point t2. That is, in the 2N operation before switching, the needle opening degree command NVR1 of the nozzles N1 and N2 where water injection was performed, and the needle opening degree command NVR4 of the nozzles N3 and N4 where water injection was not performed, vary at a constant rate by the execution of the switching operation from the 2N operation to the 4N operation, and both change from different values to the same value.

[0012] As a result, the switching operation from the 2N operation to the 4N operation is completed. Then, in the 4N operation after the switching operation, as after the time point t2, the needle opening degree command NVR1 of the nozzles N1 and N2 and the needle opening degree command NVR4 of the nozzles N3 and N4 are controlled to be the same. That is, a 4N operation is executed to rotate the runner by injecting water from the four nozzles N1, N2, N3, and N4.

[0013] [2] Switching operation from 4N operation to 2N operation (second switching operation) As shown in FIG. 8, when performing the switching operation from the 4N operation to the 2N operation, the deflector opening degree command DFR is increased compared to before performing this switching operation (when the 4N operation is being executed). For example, the deflector opening degree command DFR increases from DFRa (%) to 100% (DFRa < 100) at the time point t1 when the switching operation starts.

[0014] Accordingly, when starting the switching operation at time point t1, as the needle opening command NVR1 of nozzles N1 and N2 increases at a constant rate (K1c), the needle opening command NVR4 of nozzles N3 and N4 decreases at a constant rate (K4c). As a result, as time changes from time point t1 to time point t2, the needle opening command NVR1 of nozzles N1 and N2 and the needle opening command NVR4 of nozzles N3 and N4 change from the same state to different states. For example, the needle opening command NVR1 of nozzles N1 and N2 increases from NVRa (%) to 100% (0 < NVRa < 100) between time point t1 and time point t2. In contrast, the needle opening command NVR4 of nozzles N3 and N4 decreases from NVRa (%) to 0% between time point t1 and time point t2. That is, in the 4N operation before switching, the needle opening commands NVR1 of nozzles N1 and N2 that perform water injection and the needle opening commands NVR4 of nozzles N3 and N4 that perform water injection vary at a constant rate by executing the switching operation from the 2N operation to the 4N operation, and are controlled so that both change from the same value to different values.

[0015] As a result, the switching operation from the 4N operation to the 2N operation is completed. Then, in the 2N operation after the switching operation, like after time point t2, the needle opening command NVR1 of nozzles N1 and N2 used in the 2N operation is controlled with the needle opening command NVR4 of nozzles N3 and N4 not used in the 2N operation being 0%. That is, the 2N operation is executed to rotate the runner by injecting water from the two nozzles N1 and N2.

[0016] [3] Problems However, during the switching operation of changing the number of nozzles used during operation in a Pelton turbine, the output of the generator may fluctuate. For this reason, it may be difficult to smoothly execute the switching operation in a Pelton turbine. At this time, the deflector opening command DFR during the nozzle number switching operation is constant at DFRa (%). As a result, after the nozzle number switching is completed, it will be controlled to the deflector opening command DFR according to the output fluctuation. In order to avoid rapid fluctuations in the power output value W after the nozzle number switching is completed, it is desirable that the power output value W during the nozzle number switching operation be constant.

[0017] Therefore, the problem to be solved by the present invention is to provide a Pelton turbine control device and a Pelton turbine control method capable of smoothly executing the switching operation of changing the number of nozzles used during operation in a Pelton turbine.

Means for Solving the Problem

[0018] The Pelton turbine control device according to the embodiment controls the operation of a Pelton turbine including a runner, a plurality of nozzles, and a plurality of deflectors, and is configured to drive a generator by the rotation of the runner. The runner has a plurality of buckets arranged in the rotational direction. The plurality of nozzles are configured to inject water into the plurality of buckets, and adjust the flow rate of the water injected into the plurality of buckets according to the needle opening degree. The plurality of deflectors are installed in each of the plurality of nozzles, and adjust the flow rate of the water acting on the plurality of buckets from the nozzles according to the deflector opening degree. The Pelton turbine control device is configured to at least execute a first turbine operation of rotating the runner by injecting water from a first nozzle among the plurality of nozzles into the plurality of buckets, and a second turbine operation of rotating the runner by injecting water from the first nozzle and a second nozzle different from the first nozzle among the plurality of nozzles into the plurality of buckets. When performing a first switching operation of switching from the first turbine operation to the second turbine operation, the Pelton turbine control device decreases the deflector opening degree compared to before performing the first switching operation, and decreases the needle opening degree of the first nozzle at a constant rate and increases the needle opening degree of the second nozzle at a constant rate until the needle opening degree of the first nozzle and the needle opening degree of the second nozzle become the same state. When the power output by the generator decreases during the first switching operation, the Pelton turbine control device decreases the rate of decreasing the needle opening degree of the first nozzle and increases the rate of increasing the needle opening degree of the second nozzle compared to before the decrease in the power output by the generator, with the deflector opening degree increased compared to before the decrease in the power output by the generator. When the power output by the generator increases during the first switching operation, the Pelton turbine control device increases the rate of decreasing the needle opening degree of the first nozzle and decreases the rate of increasing the needle opening degree of the second nozzle compared to before the increase in the power output by the generator, with the deflector opening degree decreased compared to before the increase in the power output by the generator.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 7

Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0020] [A] Configuration of the Pelton water turbine 1 FIG. 1 is a diagram schematically showing an outline of the configuration of a Pelton water turbine according to an embodiment.

[0021] As shown in FIG. 1, the Pelton water turbine 1 of the present embodiment includes a runner 10, a nozzle 30, a deflector 50, and a control device 70.

[0022] [A-1] Runner 10 The runner 10 is a rotating body (impeller) that rotates in the rotation direction R, and a plurality of buckets 13 are arranged in the rotation direction R via a disk 12 provided on a rotating shaft 11. Although not shown, the runner 10 is housed inside the housing, and the generator is configured to be driven by the rotation of the runner 10.

[0023] [A-2] Nozzle 30 The nozzle 30 is installed so as to rotate the runner 10 in the rotation direction R by ejecting water (jet water) from the ejection port to the bucket 13 constituting the runner 10.

[0024] The nozzle 30 is provided with a needle valve 31 inside. The needle valve 31 is provided to adjust the flow rate of the water ejected from the ejection port of the nozzle 30 to the bucket 13 according to the needle opening degree using a needle. The nozzle 30 is configured to increase the flow rate of the water ejected from the ejection port of the nozzle 30 to the bucket 13 as the required needle opening degree increases.

[0025] There are a plurality of nozzles 30, and the plurality of nozzles 30 are arranged around the runner 10. The plurality of nozzles 30 have the same configuration as each other.

[0026] In FIG. 1, two nozzles 30 are shown, but the Pelton water turbine 1 of the present embodiment includes, for example, four nozzles 30. When each of the four nozzles 30 is to be described separately, each of the four nozzles 30 is appropriately referred to as nozzle N1, nozzle N2, nozzle N3, and nozzle N4.

[0027] [A-3] Deflector 50 The deflector 50 is configured to vary the flow rate of water acting on the bucket 13 from the nozzle outlet of the nozzle 30 according to the deflector opening degree. The deflector 50 is configured to increase the flow rate of water ejected from the nozzle outlet of the nozzle 30 to the bucket 13 as the required deflector opening degree increases.

[0028] There are a plurality of deflectors 50, and each of the plurality of deflectors 50 is rotatably installed at each of the plurality of nozzles 30.

[0029] [B] Driving mechanism of the Pelton turbine 1 FIG. 2 is a diagram schematically showing an outline of a driving mechanism for driving the Pelton turbine according to the embodiment.

[0030] As shown in FIG. 2, the Pelton turbine 1 is configured to be driven by a control device 70, a deflector driving unit 500, and needle valve driving units 300a to 300d.

[0031] [B-1] Control device 70 The control device 70 (Pelton turbine control device) is provided to execute the operation of the Pelton turbine 1 (see FIG. 1) by controlling the operations of the deflector driving unit 500 and the needle valve driving units 300a to 300d. The control device 70 includes an arithmetic unit (not shown) and a memory device (not shown), and is configured to control the operations of each part by the arithmetic unit performing arithmetic processing using a program stored in the memory device.

[0032] Here, the control device 70 is a nozzle number switching device, and is configured to switch and execute 2N operation (first turbine operation) and 4N operation (second turbine operation) in the Pelton turbine 1.

[0033] Specifically, when executing 2N operation, the control device 70 rotates the runner 10 by ejecting water from two nozzles N1 and N2 (first nozzles) out of the four nozzles 30 to the bucket 13.

[0034] When performing 4N operation, the control device 70 injects water into the bucket 13 from two nozzles N1 and N2 (first nozzles) that inject water during 2N operation, and from two other nozzles N3 and N4 (second nozzles) different from the two nozzles N1 and N2. That is, when performing 4N operation, the runner 10 is rotated by injecting water into the bucket 13 from all four nozzles 30 (N1 to N4) (see FIG. 1).

[0035] In the present embodiment, the control device 70 includes a speed controller 71 and a needle controller 72.

[0036] Among the control device 70, the speed controller 71 is configured to output a deflector opening command DFR for the deflector 50 (see FIG. 1).

[0037] Among the control device 70, the needle controller 72 is configured to output needle opening commands NVR1 to NVR4 for a plurality of nozzles 30 (N1 to N4).

[0038] Details of the speed controller 71 and the needle controller 72 will be described later.

[0039] [B-2] Deflector drive unit 500 The deflector drive unit 500 includes a position detector 501, a subtracter 502, a drive device 503, a pressure distribution valve 504, and a servo motor 505, and drives the deflector 50 so as to be the deflector opening command DFR output from the speed controller 71.

[0040] [B-2-1] Position detector 501 In the deflector drive unit 500, the position detector 501 is configured to output a deflector opening detection value DFA by detecting the deflector opening of the deflector 50. Here, the position detector 501 is, for example, a displacement sensor, and outputs a deflector opening detection value DFA based on the displacement generated when the servo motor 505 rotates the deflector 50.

[0041] [B-2-2] Subtractor 502 In the deflector drive unit 500, the subtractor 502 is configured to output a deflector opening deviation ΔDF based on the deflector opening command DFR output from the speed controller 71 and the deflector opening detection value DFA output from the position detector 501. Here, the subtractor 502 performs a process of subtracting the deflector opening detection value DFA from the deflector opening command DFR. As a result, the deviation (DFR - DFA = ΔDF) between the deflector opening command DFR set in the speed controller 71 and the deflector opening detection value DFA actually measured by the position detector 501 is output from the subtractor 502 as the deflector opening deviation ΔDF.

[0042] [B-2-3] Drive device 503 In the deflector drive unit 500, the drive device 503 is an electro-hydraulic converter, and based on the deflector opening deviation ΔDF output from the subtractor 502, it drives the servo motor 505 by operating the pressure distribution valve 504. As a result, the deflector 50 installed on the nozzles N1 to N4 is controlled so as to reach the deflector opening command DFR output from the speed controller 71.

[0043] [B-3] Needle valve drive units 300a to 300d The needle valve drive units 300a to 300d drive the needle valves 31 installed on the nozzles N1 to N4 so as to reach the needle opening commands NVR1 to NVR4 output as set values from the needle controller 72.

[0044] [B-3-1] Needle valve drive unit 300a The needle valve drive unit 300a includes a position detector 301a, a subtractor 302a, a drive device 303a, a pressure distribution valve 304a, and a servo motor 305a, and drives the needle valve 31 installed on the nozzle N1 so as to reach the needle opening command NVR1 output from the needle controller 72.

[0045] [B-3-1-1] Position detector 301a In the needle valve drive unit 300a, the position detector 301a is configured to output a needle opening degree detection value NV1 by detecting the needle opening degree of the nozzle N1. Here, the position detector 301a is, for example, a displacement sensor, and outputs the needle opening degree detection value NV1 based on the displacement generated when the servo motor 305a operates the needle valve 31 of the nozzle N1.

[0046] [B-3-1-2] Subtractor 302a In the needle valve drive unit 300a, the subtractor 302a is configured to output a needle opening degree deviation ΔNV1 based on the needle opening degree command NVR1 output from the needle controller 72 and the needle opening degree detection value NV1 output from the position detector 301a. Here, the subtractor 302a performs a process of subtracting the needle opening degree detection value NV1 from the needle opening degree command NVR1. As a result, the deviation (NVR1 - NV1 = ΔNV1) between the needle opening degree command NVR1 set in the needle controller 72 and the needle opening degree NV1 actually measured by the position detector 301a is output from the subtractor 302a as the needle opening degree deviation ΔNV1.

[0047] [B-3-1-3] Drive device 303a In the needle valve drive unit 300a, the drive device 303a is an electro-hydraulic converter, and drives the servo motor 305a by operating the pilot valve 304a based on the needle opening degree deviation ΔNV1 output from the subtractor 302a. Thereby, the nozzle N1 is controlled so as to reach the needle opening degree command NVR1 output from the needle controller 72.

[0048] [B-3-2] Needle valve drive units 300b to 300d The needle valve drive unit 300d includes a position detector 301d, a subtractor 302d, a drive device 303d, a pilot valve 304d, and a servo motor 305d, and drives the needle valve 31 installed in the nozzle N4 so as to reach the needle opening degree command NVR4 output from the needle controller 72.

[0049] Details of the needle valve drive unit 300b and the details of the needle valve drive unit 300c are omitted for the sake of illustration, but they are configured in the same manner as the needle valve drive unit 300a and the needle valve drive unit 300d. That is, the needle valve drive unit 300b drives the needle valve 31 installed in the nozzle N2 so as to become the needle opening degree command NVR2 output from the needle controller 72. Further, the needle valve drive unit 300c drives the needle valve 31 installed in the nozzle N3 so as to become the needle opening degree command NVR3 output from the needle controller 72.

[0050] Details of each part constituting the needle valve drive units 300b to 300d are the same as those of the needle valve drive unit 300a, so the description is omitted.

[0051] [C] Details of the speed governor 71 FIG. 3 is a block diagram schematically showing an outline of a speed governor 71 in a drive mechanism for driving a Pelton water turbine according to an embodiment.

[0052] As shown in FIG. 3, the speed governor 71 includes a memory circuit 711, a subtractor 712, a dead zone 713, a function generator 714, a subtractor 715, a function generator 717A, and a function generator 717B. The speed governor 71 is configured such that a power output value W, a load limit position LL, a 4N operation command 4N, and a 2N operation command 2N are input as input signals, and a deflector opening degree command DFR is output as an output signal.

[0053] Details will be described later, but different from the related art, the speed governor 71 of the present embodiment is configured to vary and output the deflector opening degree command DFR according to the variation value of the power output value W when a variation occurs in the power output value W during the execution of the switching operation for switching between 2N operation and 4N operation.

[0054] [C-1] Memory circuit 711 The memory circuit 711 receives the power output value W, the 2N operation command 2N, and the 4N operation command 4N. The power output value W is information regarding the output value of the power generated by the generator, and is input, for example, from an external detector (not shown). The 2N operation command 2N is input when performing the 2N operation. The 4N operation command 4N is input when performing the 4N operation. The 2N operation command 2N is input after startup when the deflector opening degree is equal to or less than an arbitrary opening degree. The 4N operation command 4N is input after switching from the 2N operation to the 4N operation when the deflector opening degree is equal to or greater than an arbitrary opening degree.

[0055] The memory circuit 711 includes, for example, a memory, and is configured to record the power output value W at the time of performing a switching operation (first switching operation) of switching the 2N operation to the 4N operation, or the power output value W at the time of performing a switching operation (second switching operation) of switching the 4N operation to the 2N operation, as the power output value W1.

[0056] [C-2] Subtractor 712 In addition to the power output value W, the subtractor 712 receives the power output value W1 stored in the memory circuit 711. The subtractor 712 is configured to output the deviation between the power output value W and the power output value W1 as the power deviation ΔW by performing a subtraction process of subtracting the power output value W1 stored in the memory circuit 711 from the power output value W (ΔW = W - W1).

[0057] [C-3] Dead band 713 The dead band 713 receives the power deviation ΔW from the subtractor 712. The dead band 713 is configured to output the power deviation ΔW as the power deviation ΔW1 when the absolute value of the power deviation ΔW exceeds a predetermined value (ΔW1 = ΔW ≠ 0). On the other hand, the dead band 713 outputs a zero value as the power deviation ΔW1 when the absolute value of the power deviation ΔW is less than the predetermined value (ΔW1 = 0). The dead band 713 is provided to prevent the deflector from fluctuating due to minute output fluctuations or noise.

[0058] [C-4] Function generator 714 The function generator 714 receives the power deviation ΔW1 from the dead zone 713. The function generator 714 has a function related to the power deviation ΔW1 and the load limit position bias ΔLL, and is configured to output the load limit position bias ΔLL corresponding to the power deviation ΔW1 as an output signal using this function. In the function generator 714, when the power deviation ΔW1 is zero, the load limit position bias ΔLL is zero, and as the power deviation ΔW1 increases, the load limit position bias ΔLL increases.

[0059] [C-5] Subtractor 715 When the subtractor 715 receives the load limit position bias ΔLL from the function generator 714, it also receives the load limit position LL controlled by the speed governor 71. The load limit position LL is a signal related to the control of the deflector opening command DFR and is output to the subtractor 715.

[0060] The subtractor 715 is configured to output the deviation between the load limit position LL and the load limit position bias ΔLL as the load limit position LL1 by performing a subtraction process of subtracting the load limit position bias ΔLL from the load limit position LL.

[0061] [C-6] Function generator 717A In addition to receiving the load limit position LL1 from the subtractor 715, the function generator 717A receives the 2N operation command 2N from the outside. The 2N operation command 2N is input when performing the 2N operation.

[0062] The function generator 717A has a function related to the load limit position LL1 and the deflector opening command DFR, and is configured to output the deflector opening command DFR corresponding to the load limit position LL1 as an output signal using this function when the 2N operation command 2N is input. In the function generator 717A, when the load limit position LL1 is zero, the deflector opening command DFR is zero, and as the load limit position LL1 increases, the deflector opening command DFR increases.

[0063] [C-7] Function generator 717B In addition to the load limit position LL1 being input from the subtractor 715, the function generator 717B receives a 4N operation command 4N from the outside. The 4N operation command 4N is input when performing the 4N operation.

[0064] The function generator 717B has a function related to the load limit position LL1 and the deflector opening command DFR, and when the 4N operation command 4N is input, it uses this function to output the deflector opening command DFR corresponding to the load limit position LL1 as an output signal. In the function generator 717B, when the load limit position LL1 is an arbitrary value, the deflector opening command DFR is an arbitrary value, and as the load limit position LL1 increases, the deflector opening command DFR increases. For example, during 2N operation, the load limit position LL1 is 0 - 50%, and the deflector opening is 0 - 100%. During 4N operation, the load limit position is 50 - 100%, and the deflector opening is 50 - 100%.

[0065] [D] Needle controller 72 FIG. 4 is a block diagram schematically showing the outline of the needle controller 72 in a drive mechanism for driving a Pelton turbine according to an embodiment.

[0066] As shown in FIG. 4, the needle controller 72 includes a function generator 721, a memory circuit 722A, a memory circuit 722B, a ramp signal generator 724, a subtractor 725, a multiplier - divider 726A, a multiplier - divider 726B, and a subtractor 727.

[0067] The needle controller 72 is configured such that the deflector opening command DFR is input as an input signal and outputs the needle opening command NVR1 and the needle opening command NVR4 as output signals. The needle opening command NVR1 is a command regarding the needle opening of one of the two nozzles N1, N2 (the first nozzle) used when performing 2N operation and 4N operation. The needle opening command NVR4 is a command regarding the needle opening of one of the two nozzles N3, N4 (the second nozzle) used when performing 4N operation but not used when performing 2N operation.

[0068] When executing 2N operation and 4N operation, the needle opening command NVR2 (see Fig. 2) regarding the needle opening of the other nozzle N2 among the two nozzles N1 and N2 (the first nozzle) used is obtained in the same manner as the needle opening command NVR1, so the illustration and description thereof are omitted. Also, the needle opening command NVR3 regarding the needle opening of the other nozzle N3 among the two nozzles N3 and N4 (the second nozzle) used when executing 4N operation without using 2N operation is obtained in the same manner as the needle opening command NVR4, so the illustration and description thereof are omitted.

[0069] Similar to the related art case, when the needle controller 72 of this embodiment executes a switching operation for switching between 2N operation and 4N operation, it varies and outputs the needle opening command NVR1 and the needle opening command NVR4 according to the deflector opening command DFR output as a set value from the speed controller 71.

[0070] [D-1] Function generator 721 The function generator 721 receives the deflector opening command DFR from the speed controller 71.

[0071] The function generator 721 has a function regarding the deflector opening command DFR and the needle opening command NVR, and is configured to output, as an output signal, the needle opening command NVR corresponding to the deflector opening command DFR using that function. In the function generator 721, as the deflector opening command DFR increases, the needle opening command NVR increases.

[0072] [D-2] Memory circuit 722A In addition to receiving the needle opening command NVR from the function generator 721, the memory circuit 722A receives the 2N operation command 2N from the outside. When 2N operation is being executed before the switching operation, the memory circuit 722A stores the needle opening command NVR input from the function generator 721 as the needle opening command NVR2N.

[0073] [D-3] Memory Circuit 722B In addition to receiving the needle opening command NVR from the function generator 721, the memory circuit 722B receives the 4N operation command 4N from the outside. When the 4N operation is being executed before the switching operation, the memory circuit 722B stores the needle opening command NVR input from the function generator 721 as the needle opening command NVR4N.

[0074] [D-4] Lamp Signal Generator 724 The lamp signal generator 724 receives the 2N operation command 2N and the 4N operation command 4N. Based on the 2N operation command 2N and the 4N operation command 4N, the lamp signal generator 724 outputs the lamp signal K.

[0075] When the lamp signal generator 724 performs a switching operation (first switching operation) to switch from the 2N operation to the 4N operation, it outputs a lamp signal K that is set to increase in value at a constant rate from zero to a predetermined value (for example, 10000). In contrast, when performing a switching operation (second switching operation) to switch from the 4N operation to the 2N operation, the lamp signal generator 724 outputs a lamp signal K that is set to decrease in value at a constant rate from a predetermined value (for example, 10000) to zero.

[0076] [D-5] Subtractor 725 The subtractor 725 receives the needle opening command NVR2N from the memory circuit 722A and, at the same time, receives the needle opening command NVR4N from the memory circuit 722B. The subtractor 725 performs a subtraction process of subtracting the needle opening command NVR2N from the needle opening command NVR4N. As a result, the deviation (NVR4N - NVR2N = ΔN1) between the needle opening command NVR4N and the needle opening command NVR2N is output from the subtractor 725 as the needle opening deviation ΔN1.

[0077] [D-6] Multiplier / Divider 726A When the needle opening deviation ΔN1 is input from the subtracter 725, the multiplier / divider 726A also receives the lamp signal K from the memory circuit 722B. The multiplier / divider 726A executes a process of dividing the integrated value obtained by integrating the needle opening deviation ΔN1 with the lamp signal K by a predetermined value (for example, 10,000). As a result, the needle opening deviation ΔN2 is output from the multiplier / divider 726A.

[0078] [D-7]Multiplier / Divider 726B When the needle opening command NVR4N is input from the memory circuit 722B, the multiplier / divider 726B also receives the lamp signal K from the memory circuit 722B. The multiplier / divider 726A executes a process of dividing the integrated value obtained by integrating the needle opening command NVR4N with the lamp signal K by a predetermined value (for example, 10,000). As a result, the needle opening command NVR4 is output from the multiplier / divider 726B.

[0079] [D-8]Subtracter 727 When the needle opening command NVR2N is input from the memory circuit 722A, the subtracter 727 also receives the needle opening deviation ΔN2 from the multiplier / divider 726A. The subtracter 727 performs a subtraction process of subtracting the needle opening deviation ΔN2 from the needle opening command NVR2N. As a result, the needle opening command NVR2N is output from the subtracter 727.

[0080] [E]Operation The operation of the Pelton turbine 1 of the present embodiment will be described.

[0081] Here, in the Pelton turbine 1, when the output fluctuation of the generator does not occur during the execution of the switching operation from 2N operation to 4N operation and during the execution of the switching operation from 4N operation to 2N operation (normal time; when ΔW1 = 0 in FIG. 3), and when the output fluctuation of the generator occurs (during output fluctuation; when ΔW1 ≠ 0 in FIG. 3), the description will be divided into two cases.

[0082] [E-1]Switching Operation from 2N Operation to 4N Operation [E-1-1]Normal Time (Case 1) When there is no output fluctuation of the generator during the execution of the switching operation (the first switching operation) from 2N operation to 4N operation, the deflector opening command DFR, the needle opening command NVR1, the needle opening command NVR4, etc. are controlled in the same manner as in the related art case (see Fig. 7).

[0083] Specifically, as shown in Fig. 7, when executing the switching operation from 2N operation to 4N operation, the deflector opening command DFR is decreased (100% → DFRa (%)) compared to before performing the switching operation. Then, with the deflector opening command DFR decreased compared to before performing the switching operation, the needle opening command NVR1 of the nozzles N1, N2 is decreased at a certain ratio (K1a), and at the same time, the needle opening command NVR4 of the nozzles N3, N4 is increased at a certain ratio (K4a). As a result, the needle opening command NVR1 of the nozzles N1, N2 and the needle opening command NVR4 of the nozzles N3, N4 become the same state (NVR1 = NVR4 = NVRa), and 4N operation is executed (see Fig. 7).

[0084] [E-1-2]When output decrease occurs (Case 1-1) Fig. 5A is a diagram showing the operation when the power output by the generator decreases during the execution of the switching operation from 2N operation to 4N operation in the Pelton turbine 1 of the embodiment. In Fig. 5A, the transitions of the power output value W, the load limit position LL1, the deflector opening command DFR, the lamp signal K, and the needle opening command NVR are shown in time series.

[0085] In Fig. 5A, the case where the power output value W decreases during the execution of the switching operation from 2N operation to 4N operation (between time point t1 and time point t2) is illustrated. As shown in Fig. 5A, the power output value W decreases from Wa to Wb (Wa > Wb) between the time point t1a (start point of fluctuation) after the time point t1 when the switching operation is started and the time point t1b (end point of fluctuation) before the time point t2 when the switching operation is completed.

[0086] Accordingly, the value of the load limit position LL1 increases from LLa to LLb (LLa < LLb) between time point t1a and time point t1b. The deflector opening command DFR increases from DFRa to DFRb (DFRa < DFRb) between time point t1a and time point t1b.

[0087] In the execution of the switching operation, the rate of decrease of the needle opening command NVR1 for the nozzles N1 and N2 is smaller than before the decrease in the power output value W. That is, the rate of decrease of the needle opening command NVR1 for the nozzles N1 and N2 is K1a before the decrease in the power output value W (before time point t1a), while it is K1b smaller than K1a after the decrease in the power output value W (after time point t1a) (K1a > K1b).

[0088] On the other hand, in the execution of the switching operation, the rate of increase of the needle opening command NVR4 for the nozzles N3 and N4 increases compared to before the decrease in the power output value W. That is, the rate of increase of the needle opening command NVR4 for the nozzles N3 and N4 is K4a before the decrease in the power output value W (before time point t1a), while it is K4b larger than K4a after the decrease in the power output value W (after time point t1a) (K4a < K4b).

[0089] As a result, the power output value W rises at time point t1c after time point t1b, and returns from Wb to Wa from time point t1c to time point t1d. Accordingly, the load limit position LL1 decreases at time point t1c and returns from LLb to LLa. And the value of the deflector opening command DFR decreases at time point t1c and returns from DFRb to DFRa.

[0090] Then, the rate of the needle opening command NVR1 for the nozzles N1 and N2 and the rate of the needle opening command NVR4 for the nozzles N3 and N4 change again at time point t1c. And at time point t2 when the switching operation is completed, the needle opening command NVR1 for the nozzles N1 and N2 and the needle opening command NVR4 for the nozzles N3 and N4 are in the same state (NVR1 = NVR4 = NVRb).

[0091] [E-1-2] When output increase occurs (Case 1-2) FIG. 5B is a diagram showing the operation when the power output from the generator increases during the switching operation of switching from 2N operation to 4N operation in the Pelton turbine 1 of the embodiment. In FIG. 5B, similar to FIG. 5A, the transitions of each part are shown in time series.

[0092] In FIG. 5B, the case where the power output value W increases during the execution of the switching operation of switching from 2N operation to 4N operation (between time point t1 and time point t2) is illustrated. As shown in FIG. 5A, the power output value W increases from Wa to Wb (Wa < Wb) between time point t1a after the start of the switching operation and time point t1b before the completion of the switching operation.

[0093] Accordingly, the value of the load limit position LL1 decreases from LLa to LLb (LLa > LLb) between time point t1a and time point t1b. The deflector opening command DFR decreases from DFRa to DFRb (DFRa > DFRb) between time point t1a and time point t1b.

[0094] The rate of decreasing the needle opening command NVR1 of the nozzles N1, N2 in the execution of the switching operation increases compared to before the decrease in the power output value W. That is, the rate of decreasing the needle opening command NVR1 of the nozzles N1, N2 is K1a before the decrease in the power output value W (before time point t1a), while it becomes K1b greater than K1a after the decrease in the power output value W (after time point t1a) (K1a < K1b).

[0095] On the other hand, the rate of increasing the needle opening command NVR4 of the nozzles N3, N4 in the execution of the switching operation decreases compared to before the decrease in the power output value W. That is, the rate of increasing the needle opening command NVR4 of the nozzles N3, N4 is K4a before the decrease in the power output value W (before time point t1a), while it becomes K4b smaller than K4a after the decrease in the power output value W (after time point t1a) (K4a > K4b).

[0096] As a result, the power output value W decreases at time t1c after time t1b, and returns from Wb to Wa from time t1c to time t1d. Along with this, the load limit position LL1 rises at time t1c and returns from LLb to LLa. And the value of the deflector opening command DFR rises at time t1c and returns from DFRb to DFRa.

[0097] And the ratio of the needle opening command NVR1 for the nozzles N1, N2, and the ratio of the needle opening command NVR4 for the nozzles N3, N4 change again at time t1c. And at time t2 when the switching operation is completed, the needle opening command NVR1 for the nozzles N1, N2 and the needle opening command NVR4 for the nozzles N3, N4 are in the same state (NVR1 = NVR4 = NVRb).

[0098] [E-2]Switching operation from 4N operation to 2N operation [E-2-1]Normal time (Case 2) Even when there is no output fluctuation of the generator during the execution of the switching operation (second switching operation) to switch from 4N operation to 2N operation, the deflector opening command DFR, the needle opening command NVR1, and the needle opening command NVR4, etc. are controlled in the same manner as in the related art (see FIG. 8).

[0099] Specifically, as shown in FIG. 8, when performing the switching operation to switch from 4N operation to 2N operation, the deflector opening command DFR is increased (DFRa(%) → 100%) compared to before performing the switching operation. And while increasing the needle opening command NVR1 for the nozzles N1, N2 at a certain ratio (K1c) in a state where the deflector opening command DFR has increased compared to before performing the switching operation, the needle opening command NVR4 for the nozzles N3, N4 is decreased at a certain ratio (K4c). As a result, the needle opening command NVR1 for the nozzles N1, N2 and the needle opening command NVR4 for the nozzles N3, N4 change from the same state to a different state. And the needle opening command NVR4 for the nozzles N3, N4 becomes 0% (fully closed state).

[0100] [E-2-2]When output decrease occurs (Case 2-1) FIG. 6A is a diagram showing the operation when the power output by the generator decreases during the switching operation of switching from 4N operation to 2N operation in the Pelton turbine 1 of the embodiment. In FIG. 6A, similar to FIG. 5A, the transition of each part is shown in time series.

[0101] In FIG. 6A, the case where the power output value W decreases during the execution of the switching operation of switching from 4N operation to 2N operation (between time point t1 and time point t2) is illustrated. As shown in FIG. 6A, the power output value W decreases from Wa to Wb (Wa>Wb) between time point t1a after the start of the switching operation and time point t1b before the completion of the switching operation.

[0102] Accordingly, the value of the load limit position LL1 increases from LLa to LLb (LLa<LLb) between time point t1a and time point t1b. The deflector opening command DFR increases from DFRa to DFRb (DFRa<DFRb) between time point t1a and time point t1b.

[0103] The rate of increasing the needle opening command NVR1 of the nozzles N1, N2 in the execution of the switching operation increases compared to before the decrease in the power output value W. That is, the rate of increasing the needle opening command NVR1 of the nozzles N1, N2 is K1c before the decrease in the power output value W (before time point t1a), whereas it becomes K1d which is larger than K1c after the decrease in the power output value W (after time point t1a) (K1c<K1d).

[0104] The rate of decreasing the needle opening command NVR4 of the nozzles N3, N4 in the execution of the switching operation decreases compared to before the decrease in the power output value W. That is, the rate of decreasing the needle opening command NVR4 of the nozzles N3, N4 is K4c before the decrease in the power output value W (before time point t1a), whereas it becomes K4d which is smaller than K4c after the decrease in the power output value W (after time point t1a) (K4c>K4d).

[0105] As a result, the power output value W increases at time t1c after time t1b, and returns from Wb to Wa from time t1c to time t1d. Along with this, the load limit position LL1 decreases at time t1c and returns from LLb to LLa. And the value of the deflector opening command DFR decreases at time t1c and returns from DFRb to DFRa.

[0106] And the ratio of the needle opening command NVR1 of the nozzles N1, N2, and the ratio of the needle opening command NVR4 of the nozzles N3, N4 change again at time t1c. And at time t2 when the switching operation is completed, the needle opening command NVR1 of the nozzles N1, N2 and the needle opening command NVR4 of the nozzles N3, N4 are in a different state, and the needle opening command NVR4 of the nozzles N3, N4 becomes 0% (fully closed state).

[0107] [E-2-3] When Output Increases (Case 2-2) FIG. 6B is a diagram showing the operation when the power generated by the generator increases during the switching operation from 4N operation to 2N operation in the Pelton turbine 1 of the embodiment. In FIG. 6B, similar to FIG. 5A, the transitions of each part are shown in time series.

[0108] FIG. 6B illustrates the case where the power output value W increases during the execution of the switching operation from 4N operation to 2N operation (between time t1 and time t2). As shown in FIG. 6A, the power output value W increases from Wa to Wb (Wa < Wb) between time t1a after the start of the switching operation and time t1b before time t2 when the switching operation is completed.

[0109] Along with this, the value of the load limit position LL1 decreases from LLa to LLb between time t1a and time t1b (LLa > LLb). The deflector opening command DFR decreases from DFRa to DFRb between time t1a and time t1b (DFRa > DFRb).

[0110] In the execution of the switching operation, the rate of increase in the needle opening command NVR1 for nozzles N1 and N2 decreases compared to before the decrease in the power output value W. That is, the rate of increase in the needle opening command NVR1 for nozzles N1 and N2 is K1c before the decrease in the power output value W (before time point t1a), whereas it becomes K1d, which is smaller than K1c, after the decrease in the power output value W (after time point t1a) (K1c > K1d).

[0111] In the execution of the switching operation, the rate of decrease in the needle opening command NVR4 for nozzles N3 and N4 increases compared to before the decrease in the power output value W. That is, the rate of decrease in the needle opening command NVR4 for nozzles N3 and N4 is K4c before the decrease in the power output value W (before time point t1a), whereas it becomes K4d, which is larger than K4c, after the decrease in the power output value W (after time point t1a) (K4c < K4d).

[0112] As a result, the power output value W decreases at time point t1c after time point t1b, and returns from Wb to Wa from time point t1c to time point t1d. Along with this, the load limit position LL1 rises at time point t1c and returns from LLb to LLa. And the value of the deflector opening command DFR rises at time point t1c and returns from DFRb to DFRa.

[0113] Then, the rates of the needle opening command NVR1 for nozzles N1 and N2 and the needle opening command NVR4 for nozzles N3 and N4 change again at time point t1c. At time point t2 when the switching operation is completed, the needle opening command NVR1 for nozzles N1 and N2 and the needle opening command NVR4 for nozzles N3 and N4 are in a different state, and the needle opening command NVR4 for nozzles N3 and N4 becomes 0% (fully closed state).

[0114] [F] Summary As described above, in the present embodiment, when the power output value W fluctuates during the switching operation of switching between 2N operation and 4N operation, the deflector opening command DFR is adjusted according to the value by which the power output value W has fluctuated. Accordingly, in the present embodiment, the rate of change of the needle opening commands NVR1 for the nozzles N1 and N2 and the needle opening commands NVR4 for the nozzles N3 and N4 changes from the rate before the change in the power output value W, as described above (see FIGS. 5A, 5B, 6A, and 6B).

[0115] Therefore, in the present embodiment, even when the power output value W fluctuates during the switching operation, the change in the power output value W is suppressed and adjusted to the value W after the change. That is, in the present embodiment, the change in the power output value W can be reduced.

[0116] Therefore, in the present embodiment, even when the output of the generator fluctuates during the execution of the switching operation of changing the number of nozzles 30 (N1, N2, N3, N4) used during operation in the Pelton turbine 1, the switching operation can be executed smoothly.

[0117] In the above embodiment, the Pelton turbine 1 has been described as including four nozzles 30, but the present invention is not limited to this. The Pelton turbine 1 may include a plurality (for example, two) of nozzles 30 other than four.

[0118] <Others> Although some embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0119] 1: Pelton turbine, 10: runner, 11: rotating shaft, 12: disk, 13: bucket, 30: nozzle, 31: needle valve, 50: deflector, 70: control device, 71: governor, 72: needle controller, 300a: needle valve drive unit, 300b: needle valve drive unit, 300c: needle valve drive unit, 300c: needle valve drive unit, 300d: needle valve drive unit, 301a: position detector, 301d: position detector, 302a: subtracter, 302d: subtracter, 303a: drive device, 303d: drive device, 304a: pressure distribution valve, 304d: pressure distribution valve, 305a: servo motor, 305d: servo motor, 500: deflector drive unit, 501: position detector, 502: subtracter, 503: drive device, 504: pressure distribution valve, 505: servo motor, 711: memory circuit, 712: subtracter, 713: dead zone, 714: function generator, 715: subtracter, 717: function generator, 721: function generator, 722: memory circuit, 724: lamp signal generator, 725: subtracter, 726: multiplier / divider, 727: subtracter, N1: nozzle, N2: nozzle, N3: nozzle, N4: nozzle

Claims

1. A runner having a plurality of buckets arranged in a rotational direction; A plurality of nozzles configured to inject water into the plurality of buckets and adjust a flow rate of the water injected into the plurality of buckets in accordance with a needle opening degree; a plurality of deflectors that are installed in the plurality of nozzles, and adjust the flow rate of water acting on the plurality of buckets from the nozzles in accordance with an opening degree of the deflector; A Pelton turbine control device for controlling an operation of a Pelton turbine configured to drive a generator by rotation of the runner, comprising: The turbine is configured to at least perform a first hydraulic turbine operation in which the runner is rotated by injecting water from a first nozzle of the plurality of nozzles into the plurality of buckets, and a second hydraulic turbine operation in which the runner is rotated by injecting water from the first nozzle and a second nozzle different from the first nozzle of the plurality of nozzles into the plurality of buckets, When performing a first switching operation for switching from the first hydraulic turbine operation to the second hydraulic turbine operation, a needle opening of the first nozzle is decreased at a constant rate and a needle opening of the second nozzle is increased at a constant rate until the needle opening of the first nozzle and the needle opening of the second nozzle become the same in a state in which a deflector opening is decreased compared to before the first switching operation is performed; when the power output by the generator is reduced during the first switching operation, a rate at which the needle opening of the first nozzle is reduced is reduced compared to before the power output by the generator is reduced, and a rate at which the needle opening of the second nozzle is increased is increased compared to before the power output by the generator is reduced, while a deflector opening is increased compared to before the power output by the generator is reduced; when the power output by the generator increases during the first switching operation, a rate at which the needle opening of the first nozzle is reduced is increased compared to before the power output by the generator is increased, and a rate at which the needle opening of the second nozzle is increased is decreased compared to before the power output by the generator is increased, in a state in which the deflector opening is reduced compared to before the power output by the generator is increased. Pelton turbine control device.

2. When performing a second switching operation for switching from the second hydraulic turbine operation to the first hydraulic turbine operation, in a state in which a deflector opening is increased compared to before the second switching operation, the needle opening of the first nozzle and the needle opening of the second nozzle are the same, and the needle opening of the first nozzle is increased at a constant rate and the needle opening of the second nozzle is decreased at a constant rate, when the power output by the generator is reduced during the second switching operation, a rate at which the needle opening of the first nozzle is increased is increased compared to before the power output by the generator is reduced, and a rate at which the needle opening of the second nozzle is reduced is decreased compared to before the power output by the generator is reduced, in a state in which a deflector opening is increased compared to before the power output by the generator is reduced; when the power output by the generator is increased during the second switching operation, a rate at which the needle opening of the first nozzle is increased is decreased compared to before the power output by the generator is increased, and a rate at which the needle opening of the second nozzle is decreased is increased compared to before the power output by the generator is increased, in a state in which the deflector opening is decreased compared to before the power output by the generator is increased. The Pelton turbine control device according to claim 1 .

3. A runner having a plurality of buckets arranged in a rotational direction; a plurality of nozzles configured to inject water into the plurality of buckets, the flow rate of the water injected into the plurality of buckets being adjusted by varying a needle opening; a plurality of deflectors that are provided in the plurality of nozzles, respectively, and adjust the flow rate of water acting on the plurality of buckets from the nozzles by varying the deflector opening degree; A Pelton turbine control method for controlling operation of a Pelton turbine configured to drive a generator by rotation of the runner, comprising: When performing a first switching operation to switch from a first hydraulic turbine operation in which the runner is rotated by injecting water from a first nozzle of the plurality of nozzles into the plurality of buckets to a second hydraulic turbine operation in which the runner is rotated by injecting water from the first nozzle and a second nozzle different from the first nozzle into the plurality of buckets, a needle opening of the first nozzle is decreased at a constant rate and a needle opening of the second nozzle is increased at a constant rate until the needle opening of the first nozzle and the needle opening of the second nozzle become the same, with a deflector opening reduced compared to before the first switching operation is performed; when the power output by the generator is reduced during the first switching operation, a rate at which the needle opening of the first nozzle is reduced is reduced compared to before the power output by the generator is reduced, and a rate at which the needle opening of the second nozzle is increased is increased compared to before the power output by the generator is reduced, while a deflector opening is increased compared to before the power output by the generator is reduced; when the power output by the generator increases during the first switching operation, a rate at which the needle opening of the first nozzle is reduced is increased compared to before the power output by the generator is increased, and a rate at which the needle opening of the second nozzle is increased is decreased compared to before the power output by the generator is increased, in a state in which the deflector opening is reduced compared to before the power output by the generator is increased. Pelton turbine control method.

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