Load adjusting method for multi-nozzle pelton turbine

Abstract

The invention discloses a load adjusting method for a multi-nozzle pelton turbine, relates to the field of power generation, and aims to comprehensively shorten the load adjusting time of the multi-nozzle pelton turbine. According to the technical scheme, the load adjusting method for the multi-nozzle pelton turbine comprises the steps that firstly, the pelton turbine is started; then the number, the positions and the target opening degree of the nozzles needing to be put are determined; and the number and position of the input nozzles are maintained for operation, or the load is adjusted. When the input nozzles can be directly adjusted to the nozzles needing to be input by increasing or reducing the nozzles, all the nozzles needing to be adjusted are directly adjusted to the corresponding target opening degrees at the same time; and when the input nozzles cannot be directly adjusted into the nozzles needing to be input by increasing or reducing the nozzles, the nozzles are firstly adjusted to the transition state, and then all the nozzles needing to be adjusted are simultaneously adjusted to respective corresponding target opening degrees. The method is suitable for load adjustment of the multi-nozzle pelton turbine under all conditions.

Description

Technical Field

[0001] The invention relates to the field of power generation, and in particular to a method for adjusting the load of a multi-nozzle Pelton turbine. Background Art

[0002] Wind and photovoltaic power generation are considered one of the main ways to adjust the energy structure. Since wind and photovoltaic power generation are affected by external meteorological conditions, their power generation is random and intermittent, so they need to be operated in a complementary manner with hydropower units that have high stability and strong response capabilities. In the mode of bundling wind and photovoltaic new energy bases nearby to access the grid, the sawtooth wind and photovoltaic new energy can be adjusted to smooth and stable electricity, improving the consumption of wind and photovoltaic energy.

[0003] Hydropower units can be divided into different types according to their structural type, such as Pelton, Mixed Flow, etc. Pelton units are suitable for higher heads, usually 500 to 1000m, or even higher. Small Pelton turbines usually have 2 nozzles, and large Pelton turbines usually have 6 nozzles. For example, Figure 1 This is a schematic diagram of the arrangement of the six nozzles of a six-nozzle Pelton turbine. Nozzles 1, 2, 3, 4, 5 and 6 are arranged at equal central angles in a clockwise direction, and the central angles corresponding to any two adjacent nozzles are 60°.

[0004] When adjusting the load of a multi-nozzle Pelton turbine, including increasing or decreasing the load, the number of nozzles to be used needs to be adjusted according to the load size. When adjusting the number of nozzles for a Pelton turbine, except for a single nozzle, the balance of radial forces generally needs to be considered. Figure 1 For the 6-nozzle Pelton turbine shown, there are four situations in which the nozzles are put into operation in a radial force balance state: the first situation is 2-nozzle balance: nozzles No. 1 and No. 4 are put into operation at the same time, or nozzles No. 2 and No. 5 are put into operation at the same time, or nozzles No. 3 and No. 6 are put into operation at the same time; the second situation is 3-nozzle balance: nozzles No. 1, No. 3 and No. 5 are put into operation at the same time, or nozzles No. 2, No. 4 and No. 6 are put into operation at the same time; the third situation is 4-nozzle balance: nozzles No. 1, No. 4, No. 2 and No. 5 are put into operation at the same time, or nozzles No. 1, No. 4, No. 3 and No. 6 are put into operation at the same time, or nozzles No. 2, No. 5, No. 3 and No. 6 are put into operation at the same time; the fourth situation is 6-nozzle balance: nozzles No. 1 to No. 6 are all put into operation.

[0005] In the process of the nozzle of the multi-nozzle Pelton turbine opening from a small opening to a full opening, the efficiency of the multi-nozzle Pelton turbine will go through a repeated process of "efficiency increase → efficiency reaches the highest → efficiency decreases". The efficiency here refers to the efficiency of converting water energy into the power output of the shaft end of the multi-nozzle Pelton turbine. Figure 2 After the water flow hits the runner, output power is generated at the shaft end. During this period, there will be energy loss. The ratio of the output power to the energy of the water flow itself is called the efficiency of the turbine, which is Figure 2Vertical axis.

[0006] At present, the common practice in the industry is that in order to optimize the efficiency of multi-nozzle Pelton turbines under different load conditions, the nozzles of multi-nozzle Pelton turbines are gradually opened in sequence during the process from no-load to full load. For 6-nozzle Pelton turbines, a single nozzle is usually used for startup, and 2 nozzles are connected to the grid. As the output increases, the number of nozzles put into operation gradually increases, and the unit gradually increases the load to the rated load. In the process of increasing the load of a 6-nozzle Pelton turbine, the number of nozzles put into operation usually increases gradually in the manner of "2→4→6"; in the process of reducing the load, the number of nozzles put into operation usually decreases gradually in the manner of "6→4→2". The specific process of increasing the load of a 6-nozzle Pelton turbine to the rated load is as follows:

[0007] (1) The 2 nozzles of the 6-nozzle Pelton turbine are in the same straight line and are put into operation. Assuming that the 1st and 4th nozzles are put into operation and connected to the grid, the unit output will gradually increase;

[0008] (2) When the unit output reaches a certain rated output, for example, about 40% of the rated output, if the two-nozzle operation is maintained, the efficiency of the Pelton turbine will continue to decrease, so it is necessary to switch to four-nozzle operation;

[0009] (3) When four nozzles are put into use, in order to maintain the uniformity of the jets of each nozzle, it is necessary to reduce the opening of the already put into use No. 1 and No. 4 nozzles first, that is, first reduce the output of No. 1 and No. 4 nozzles, and open No. 2 and No. 5 nozzles at the same time. When the openings of the four nozzles put into use are consistent, the four nozzles are in a balanced state;

[0010] (4) When the four nozzles are in a balanced state, the openings of the No. 1, No. 2, No. 4 and No. 5 nozzles are increased at the same time, and the unit output gradually increases until a certain rated output is reached, for example, until about 72% of the rated output. At this time, if the four nozzles are continued to operate, the efficiency will continue to drop significantly, so it is necessary to switch to the six nozzles operation;

[0011] (5) Similarly, when 6 nozzles are put into use, in order to maintain the uniformity of the jets of each nozzle, it is necessary to reduce the opening of the already put into use No. 1, No. 2, No. 4 and No. 5 nozzles, that is, first reduce the output of these nozzles, and open No. 3 and No. 6 at the same time. When the openings of No. 1 to No. 6 nozzles are consistent, the 6 nozzles are in a balanced state;

[0012] (6) When the 6 nozzles are in a balanced state, increase the openings of nozzles 1 to 6 at the same time until the unit reaches rated output.

[0013] The process of reducing the load from the rated output is the reverse process of the above-mentioned process of increasing the load.

[0014] According to the operating experience of the completed power stations, it takes at least 5 to 15 minutes for a multi-nozzle Pelton turbine to go from no-load grid connection to full load. This cannot fully meet the current grid's requirements for the rate at which hydropower units increase or decrease loads, and it cannot meet the future requirements for large-scale wind and photovoltaic power generation to respond quickly to changes in meteorological conditions.

[0015] The patent application publication number CN 116201681 A discloses a method for quickly adjusting the load of a multi-nozzle Pelton turbine. The method is based on the number and position of the nozzles that have been put into operation, and according to the load adjustment target and the radial force balance requirement, determines the number, position and target opening of the nozzles that need to be put into operation, and then directly adjusts all the nozzles that need to be adjusted to their corresponding target openings at the same time. The method requires that both the nozzles that have been put into operation and the nozzles that need to be put into operation meet the radial force balance requirements, and that the radial force balance requirements are always met during the adjustment process, which has certain limitations. For example, for a 6-nozzle Pelton turbine, when the number of nozzles that have been put into operation → the number of nozzles that need to be put into operation is: 2 nozzles → 3 nozzles, 3 nozzles → 4 nozzles, 4 nozzles → 3 nozzles, or 3 nozzles → 2 nozzles, on the premise of meeting the radial force balance requirements, all the nozzles that need to be adjusted cannot be directly adjusted to their corresponding target openings at the same time.

[0016] In addition, the startup process of the Pelton turbine is start-up, idling, and no-load. When the no-load state is reached and the grid-connected conditions are met (frequency and voltage meet certain requirements), the grid-connected load can be carried out. Among them, the initial working condition of the Pelton turbine is that all nozzles are closed. After the Pelton turbine is started, the nozzle opening is gradually opened, the flow of the turbine gradually increases, and the speed gradually increases, and then it reaches the idling state, at which time the speed is the rated speed. On the basis of the idling state, the excitation system is put into operation, and it becomes a no-load state. For a 6-nozzle Pelton turbine, a single or two nozzles are usually used to start the machine and reach the no-load state. The entire startup process takes a long time. Summary of the invention

[0017] The invention provides a load adjustment method for a multi-nozzle Pelton turbine, aiming at comprehensively shortening the time required for adjusting the load of the multi-nozzle Pelton turbine.

[0018] The technical solution adopted by the present invention is: a method for load adjustment of a multi-nozzle Pelton turbine, firstly, starting the Pelton turbine according to the target of load adjustment; then, determining the number, position and target opening of the nozzles to be put into operation according to the target of load adjustment and the requirement of radial force balance; then, maintaining the number and position of the nozzles put into operation according to the target of load adjustment, or adjusting the load according to the following method:

[0019] When the nozzles that have been put into use can be directly adjusted to the nozzles that need to be put into use by adding nozzles or reducing nozzles, based on the number and positions of the nozzles that have been put into use, all the nozzles that need to be adjusted are directly adjusted to their corresponding target openings at the same time by adding nozzles or reducing nozzles;

[0020] When the nozzles already in operation cannot be directly adjusted to the nozzles that need to be put into operation by adding or reducing nozzles, based on the number and positions of the nozzles already in operation, by adding or reducing nozzles, first adjust them to a transitional state that meets the requirements of radial force balance, and then directly adjust all the nozzles that need to be adjusted to their corresponding target openings at the same time.

[0021] In order to shorten the startup process, the number of nozzles to be put into operation is determined according to the percentage of the given load. Furthermore, when starting the Pelton turbine, at least 3 nozzles are put into operation, or all nozzles are put into operation. For example, for a 6-nozzle Pelton turbine, if the given load does not exceed 20%, 4 nozzles are put into operation; if the given load exceeds 20%, 6 nozzles are put into operation.

[0022] Load adjustment includes two situations: increasing or decreasing the load. For a 6-nozzle Pelton turbine, the number of nozzles required is: single nozzle, 2 nozzles, 3 nozzles, 4 nozzles and 6 nozzles, a total of 5 situations.

[0023] When the load is increased: if 1 nozzle has been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 2, 3, 4, or 6; if 2 nozzles have been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 3, 4, or 6; if 3 nozzles have been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 4, or 6; if 4 nozzles have been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 6;

[0024] When reducing the load: if 6 nozzles have been put into operation before the load adjustment, 4, 3, 2 or 1 nozzles need to be put into operation after the load adjustment; if 4 nozzles have been put into operation before the load adjustment, 3, 2 or 1 nozzles need to be put into operation after the load adjustment; if 3 nozzles have been put into operation before the load adjustment, 2 or 1 nozzles need to be put into operation after the load adjustment; if 2 nozzles have been put into operation before the load adjustment, 1 nozzle needs to be put into operation after the load adjustment.

[0025] The number of nozzles put into operation in the transition state is different from the number of nozzles put into operation before the load adjustment, and is also different from the number of nozzles put into operation after the load adjustment. Specifically: for a 6-nozzle Pelton turbine, 6 nozzles are put into operation in the transition state; the situations where the nozzles put into operation cannot be directly adjusted to the nozzles to be put into operation by adding or reducing nozzles include: 2 nozzles → 6 nozzles → 3 nozzles, 3 nozzles → 6 nozzles → 4 nozzles, 4 nozzles → 6 nozzles → 3 nozzles, 3 nozzles → 6 nozzles → 2 nozzles.

[0026] For a 6-nozzle Pelton turbine, nozzles No. 1, 2, 3, 4, 5 and 6 are arranged at equal central angles in a clockwise direction, and the central angles corresponding to any two adjacent nozzles are 60°. The following four situations meet the radial force balance requirements: the first situation is 2-nozzle balance: nozzles No. 1 and No. 4 are put into operation at the same time, or nozzles No. 2 and No. 5 are put into operation at the same time, or nozzles No. 3 and No. 6 are put into operation at the same time; the second situation is 3-nozzle balance: nozzles No. 1, 3 and 5 are put into operation at the same time, or nozzles No. 2, 4 and 6 are put into operation at the same time; the third situation is 4-nozzle balance: nozzles No. 1, 4, 2 and 5 are put into operation at the same time, or nozzles No. 1, 4, 3 and 6 are put into operation at the same time, or nozzles No. 2, 5, 3 and 6 are put into operation at the same time; the fourth situation is 6-nozzle balance: nozzles No. 1 to 6 are all put into operation.

[0027] The beneficial effects of the present invention are as follows: the present invention takes reaching the target load as quickly as possible as the first purpose, rather than taking the best efficiency as the main factor and taking into account the versatility under various conditions as in the existing load adjustment methods. The efficiency of the present invention during load adjustment is not optimal, but it meets the requirements of rapid response of load adjustment of multi-nozzle Pelton turbines under specific conditions, adapts to the requirements of water-wind-solar complementarity, and is simple to operate. The present invention not only takes into account the situation that the nozzles that have been put into use can be directly adjusted to the nozzles that need to be put into use by adding nozzles or reducing nozzles, but also takes into account the situation that the nozzles that have been put into use cannot be adjusted to the nozzles that need to be put into use by adding nozzles or reducing nozzles. Therefore, it is suitable for load adjustment of all situations of multi-nozzle Pelton turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the nozzle layout of a 6-nozzle Pelton turbine.

[0029] Figure 2 This is the efficiency change curve of the 6-nozzle Pelton turbine. The horizontal axis is the ratio of the unit output to the rated output, and the vertical axis is the efficiency of the 6-nozzle Pelton turbine. DETAILED DESCRIPTION

[0030] The multi-nozzle Pelton turbine is a large or medium-sized Pelton turbine. The load adjustment method of the multi-nozzle Pelton turbine includes three steps: starting the Pelton turbine, determining the nozzles to be put into operation, and maintaining or adjusting the load. The present invention is further described below by taking a 6-nozzle Pelton turbine as an example.

[0031] Step 1: Start the Pelton turbine.

[0032] like Figure 1 As shown, the 6-nozzle Pelton turbine has 6 nozzles, namely, nozzles No. 1 to No. 6, and nozzles No. 1, No. 2, No. 3, No. 4, No. 5 and No. 6 are arranged at equal central angles in the clockwise direction, and the central angles corresponding to any two adjacent nozzles are 60°. When the 6-nozzle Pelton turbine is started, usually a single or two nozzles are started to reach the no-load state. In order to speed up the start-up process, the present invention uses more nozzles for starting, at least 3 nozzles are put into operation, or all nozzles are put into operation, and the number of nozzles put into operation is specifically determined according to the percentage of the given load. For example, for a 6-nozzle Pelton turbine, if the given load does not exceed 20% (or other set values), 4 nozzles are put into operation for rapid start-up and grid connection, and after grid connection, the 4 nozzles are simultaneously opened to a certain opening degree that the unit power meets the requirements; if the given load exceeds 20% (or other corresponding values), 6 nozzles are put into operation for rapid start-up and grid connection, and after grid connection, the 6 nozzles are simultaneously opened to a certain opening degree that the unit power meets the requirements.

[0033] Step 2: Determine the nozzles that need to be put in.

[0034] According to the load adjustment target and radial force balance requirements, determine the number, position and target opening of the nozzles to be put into operation. The number of nozzles required for a 6-nozzle Pelton turbine may be 1, that is, No. 1, No. 2, No. 3, No. 4, No. 5 or No. 6 is put into operation, and only one nozzle is put into operation. When the number of nozzles required for a 6-nozzle Pelton turbine exceeds one, the nozzles put into operation need to meet the radial force balance requirements. The following four situations meet the radial force balance requirements: the first situation is 2-nozzle balance: nozzles No. 1 and No. 4 are put into operation at the same time, or nozzles No. 2 and No. 5 are put into operation at the same time, or nozzles No. 3 and No. 6 are put into operation at the same time; the second situation is 3-nozzle balance: nozzles No. 1, No. 3 and No. 5 are put into operation at the same time, or nozzles No. 2, No. 4 and No. 6 are put into operation at the same time; the third situation is 4-nozzle balance: nozzles No. 1, No. 4, No. 2 and No. 5 are put into operation at the same time, or nozzles No. 1, No. 4, No. 3 and No. 6 are put into operation at the same time; the fourth situation is 6-nozzle balance: all nozzles No. 1 to No. 6 are put into operation.

[0035] Step 3: Maintain or adjust the load.

[0036] According to the load adjustment target, if the increase or decrease in load is small, the number and position of the nozzles put into operation are maintained, and the nozzles are adjusted to the required opening, that is, the load is maintained. The following describes the situation where the load needs to be adjusted by increasing or decreasing the number of nozzles put into operation. Load adjustment includes two situations: increasing or decreasing the load.

[0037] When the load is increased: if 1 nozzle has been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 2, 3, 4, or 6; if 2 nozzles have been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 3, 4, or 6; if 3 nozzles have been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 4, or 6; if 4 nozzles have been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 6,

[0038] When reducing the load: if 6 nozzles have been put into operation before the load adjustment, 4, 3, 2 or 1 nozzles need to be put into operation after the load adjustment; if 4 nozzles have been put into operation before the load adjustment, 3, 2 or 1 nozzles need to be put into operation after the load adjustment; if 3 nozzles have been put into operation before the load adjustment, 2 or 1 nozzles need to be put into operation after the load adjustment; if 2 nozzles have been put into operation before the load adjustment, 1 nozzle needs to be put into operation after the load adjustment.

[0039] There are two methods for adjusting the load. One is that the nozzles that need to be put into operation can be directly adjusted to the nozzles that need to be put into operation by adding or reducing nozzles, and the other is that the nozzles that have been put into operation cannot be directly adjusted to the nozzles that need to be put into operation by adding or reducing nozzles. When the nozzles that have been put into operation can be directly adjusted to the nozzles that need to be put into operation by adding or reducing nozzles, based on the number and position of the nozzles that have been put into operation, all the nozzles that need to be adjusted are directly adjusted to their corresponding target openings at the same time by adding or reducing nozzles. For details, see the method for quickly adjusting the load of a multi-nozzle Pelton turbine disclosed in the patent with publication number CN 116201681 A.

[0040] When the nozzles that have been put into operation cannot be directly adjusted to the nozzles that need to be put into operation by adding or reducing nozzles, based on the number and position of the nozzles that have been put into operation, by adding or reducing nozzles, first adjust to the transition state that meets the requirements of radial force balance, and then directly adjust all the nozzles that need to be adjusted to their corresponding target openings at the same time. For example, when the nozzles that have been put into operation cannot be directly adjusted to the nozzles that need to be put into operation by adding or reducing nozzles, for a 6-nozzle Pelton turbine, the nozzles that have been put into operation before load adjustment → the nozzles that need to be put into operation after load adjustment correspond to four situations: 2 nozzles → 3 nozzles, 3 nozzles → 4 nozzles, 4 nozzles → 3 nozzles, and 3 nozzles → 2 nozzles. The transition state is an intermediate temporary state that meets the requirements of radial force balance. The number of nozzles put into operation in the transition state is different from the number of nozzles put into operation before load adjustment, and is also different from the number of nozzles put into operation after load adjustment, but is the same as the part of nozzles put into operation before load adjustment, and is also the same as the part of nozzles put into operation after load adjustment. For a 6-nozzle Pelton turbine, 6 nozzles can be put into operation in the transition state. For example, the situations where the nozzles that have been put into use cannot be directly adjusted to the nozzles that need to be put into use by adding or reducing nozzles include: 2 nozzles → 6 nozzles → 3 nozzles, 3 nozzles → 6 nozzles → 4 nozzles, 4 nozzles → 6 nozzles → 3 nozzles, and 3 nozzles → 6 nozzles → 2 nozzles.

[0041] Taking into account that when the three nozzles are operating in radial force balance, the nozzles put into operation (No. 1 + No. 3 + No. 5, or No. 2 + No. 4 + No. 6) are significantly different from other situations, so when increasing or decreasing the load, the following strategy is followed: first determine whether the nozzles that need to be put into operation need to be 3 nozzles. If 3 nozzles are running, then while keeping the target output unchanged, switch the current number of nozzles to 6 nozzles (if 6 nozzles are already running, this step can be omitted), and then symmetrically withdraw 3 nozzles (No. 1 + No. 3 + No. 5, or No. 2 + No. 4 + No. 6), and at the same time increase the opening of the remaining 3 nozzles to the required opening. If the nozzles to be put into operation are not three nozzles, it can be further divided into two cases: Case 1: If the nozzle to be put into operation is a single nozzle, then withdraw the other nozzles that have been put into operation, and leave the single nozzle to adjust to the required opening for operation; Case 2: If the nozzle to be put into operation is multiple nozzles, determine the opening of each nozzle that is put into operation when the target load is reached (the opening of each nozzle is the same), and directly adjust the opening of each nozzle that needs to be put into operation at a predetermined rate at the same time until the opening of each nozzle reaches the target opening and the unit output meets the requirements; if it is to reduce the load, the opening of the nozzles that do not need to be put into operation will be closed to zero opening.

Claims

1. A method for adjusting load of a multi-nozzle Pelton turbine, characterized in that: First, start the Pelton turbine according to the load adjustment target; then determine the number, position and target opening of the nozzles to be put into operation according to the load adjustment target and the radial force balance requirement; then, maintain the number and position of the nozzles put into operation according to the load adjustment target, or adjust the load according to the following method: When the nozzles that have been put into use can be directly adjusted to the nozzles that need to be put into use by adding nozzles or reducing nozzles, based on the number and positions of the nozzles that have been put into use, all the nozzles that need to be adjusted are directly adjusted to their corresponding target openings at the same time by adding nozzles or reducing nozzles; When the nozzles already in operation cannot be directly adjusted to the nozzles that need to be put into operation by adding or reducing nozzles, based on the number and positions of the nozzles already in operation, by adding or reducing nozzles, first adjust them to a transitional state that meets the requirements of radial force balance, and then directly adjust all the nozzles that need to be adjusted to their corresponding target openings at the same time.

2. The multi-nozzle Pelton turbine load adjustment method according to claim 1, characterized in that: When starting up a Pelton turbine, at least three nozzles should be put into operation, or all nozzles should be put into operation.

3. The multi-nozzle Pelton turbine load adjustment method according to claim 2, characterized in that: For a 6-nozzle Pelton turbine, if the given load does not exceed 20%, 4 nozzles are put into operation; if the given load exceeds 20%, 6 nozzles are put into operation.

4. The multi-nozzle Pelton turbine load adjustment method according to any one of claims 1 to 3, characterized in that: For a 6-nozzle Pelton turbine, the number of nozzles to be put into operation is: single nozzle, 2 nozzles, 3 nozzles, 4 nozzles and 6 nozzles, a total of 5 cases; When the load is increased: if 1 nozzle has been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 2, 3, 4, or 6; if 2 nozzles have been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 3, 4, or 6; if 3 nozzles have been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 4, or 6; if 4 nozzles have been put into operation before the load adjustment, then the number of nozzles to be put into operation after the load adjustment is 6; When reducing the load: if 6 nozzles have been put into operation before the load adjustment, 4, 3, 2 or 1 nozzles need to be put into operation after the load adjustment; if 4 nozzles have been put into operation before the load adjustment, 3, 2 or 1 nozzles need to be put into operation after the load adjustment; if 3 nozzles have been put into operation before the load adjustment, 2 or 1 nozzles need to be put into operation after the load adjustment; if 2 nozzles have been put into operation before the load adjustment, 1 nozzle needs to be put into operation after the load adjustment.

5. The multi-nozzle Pelton turbine load adjustment method according to claim 4, characterized in that: In the transition state, 6 nozzles are put into operation; the situations where the nozzles that have been put into operation cannot be directly adjusted to the nozzles that need to be put into operation by adding or reducing nozzles include: 2 nozzles → 6 nozzles → 3 nozzles, 3 nozzles → 6 nozzles → 4 nozzles, 4 nozzles → 6 nozzles → 3 nozzles, 3 nozzles → 6 nozzles → 2 nozzles.

6. The method for adjusting the load of a multi-nozzle Pelton turbine according to claim 4, characterized in that: For a 6-nozzle Pelton turbine, nozzles No. 1, 2, 3, 4, 5 and 6 are arranged at equal central angles in a clockwise direction, and the central angles corresponding to any two adjacent nozzles are 60°. The following four situations meet the radial force balance requirements: the first situation is 2-nozzle balance: nozzles No. 1 and No. 4 are put into operation at the same time, or nozzles No. 2 and No. 5 are put into operation at the same time, or nozzles No. 3 and No. 6 are put into operation at the same time; the second situation is 3-nozzle balance: nozzles No. 1, 3 and 5 are put into operation at the same time, or nozzles No. 2, 4 and 6 are put into operation at the same time; the third situation is 4-nozzle balance: nozzles No. 1, 4, 2 and 5 are put into operation at the same time, or nozzles No. 1, 4, 3 and 6 are put into operation at the same time, or nozzles No. 2, 5, 3 and 6 are put into operation at the same time; the fourth situation is 6-nozzle balance: nozzles No. 1 to 6 are all put into operation.

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