JPH02286881A - Nozzle switching method for pelton hydraulic wheel - Google Patents

Abstract

PURPOSE:To eliminate variation in the output of a hydraulic wheel by increasing the degree of opening of other pairs of needle nozzles than a certain fully opened pair of needle nozzles when the output of a hydraulic wheel has increased, and changing over the nozzles in the opposite procedure to above when the output has decreased. CONSTITUTION:When load is small, needles 4 of nozzles 11, 13 are operated by a pressure distributing valve 40 to control the degree of opening so that water is jetted in a rate corresponding to the load at the current time, and thus the hydraulic wheel concerned yields an output which corresponds to this rate of water jetting. When the load has further increased requiring a rate of water jet larger than the one obtained by fully opened nozzles 11, 13, they shall be full opened, and other nozzles 12, 14 are controlled by another pressure distributing valve 41 while the degree of nozzle opening is controlled by the needles 4. Thus water is jetted in the rate corresponding to this controlled degree of opening of nozzles 12, 14 and that of the nozzles 11, 13, and the hydraulic wheel yields output correspondingly. When the load is decremental, this procedure shall be followed oppositely.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a nozzle switching method for a Pelton water turbine that switches the number of nozzles in a Pelton water turbine that grows multiple pairs of nozzles used in a water turbine generator according to the output of the water turbine. Regarding.

[Conventional technology]

Pelton water turbines of Pelton water turbine generators used in hydroelectric power plants operate with high efficiency by switching the number of nozzles according to the output of the water turbine. FIG. 2 is a system diagram of this type of Pelton turbine, and the prior art will be explained based on the diagram.

No.! In the figure, 1 is a casing through which water is guided through a penstock (not shown), and is provided surrounding the outer periphery of a runner 3 having a bucket 2 on its outer periphery. A plurality of nozzles 11, 12.
Water is injected into bucket 2 from 13.14.

A needle 4 is inserted into each of the nozzles 11 to 14,
The flow rate of water injected from the nozzles 11 to 14 is controlled by the opening degree of the needle nozzle determined by the stroke of the needle 40. The needle 4 is attached to the tip of a rod 5 attached to a piston 7 located inside the needle servo motor 6, and a spring 10 is connected to the needle servo motor 6 via a pipe 9 from a deflector pressure distribution valve 8, which will be described later.
Its opening degree is adjusted by pressure oil supplied against the pressure.

At the front of the nozzles 11 to 14, this nozzle and bucket 2 are installed.
A deflector 15 is provided to cut off the gap between the two. The deflector 15 is controlled by a speed governor, and its movement is linked to the opening degree of the needle 4. That is, deflector 1
5 is rotated by a rod 20 attached to a piston 19 located in a deflector servo motor 18 via a two-pronged lever 16. That is, pressure oil from the ports 22 and 23 of the pressure distribution valve 21 connected to the speed governor is supplied to the oil chambers on both sides of the piston 19 via the pipes 24 and 25, and the rod 200
The deflector 15 rotates by an angle whose stroke corresponds to the load via a feedback mechanism (not shown). A link 29 that is pin-coupled to a tracking cam 28 that is pin-coupled to a return lever 27 attached to the rod 5 of the needle servo motor 6 is connected to a portion of the other lever 16 . Further, the tracking cam 28 is in contact with the tip of a biloft valve 31 that moves a float valve 30 built into the deflector pressure distribution valve 8 back and forth using pressure oil.

Therefore, when the stroke of the rod 20 of the deflector servo motor 1B corresponding to the load is determined by the pressure oil passing through the pipes 24 and 25 from the pressure distribution valve 21, the deflector 1
The inclination angle of link 29.5 is determined, and the inclination angle of link 29.5 is determined accordingly. The pilot valve 31 of the deflector pressure distribution valve 8 is moved via the tracking cam 2B, and pressure oil is supplied to the needle servo motor 6 via the pipe line 9 by displacement of the float valve 30. At this time, the needle 4 is moved by the stroke of the rod 5, but the return lever 27 is fed back according to the stroke of the needle 4 by moving the tracking cam 28, and pressure oil is transferred from the deflector pressure distribution valve 8 to the needle servo motor 6. The supply of water is stopped, and the needle nozzle opening degree is controlled to be proportional to the water injection flow rate according to the load.

By the way, when the water turbine output corresponding to the load is small, water is injected only from nozzle 11.13, and water is injected only from nozzle 12.1.
4 is fully opened with needle 4. This control disables the operation of the pilot valve 31 of the deflector pressure distribution valve 8 and fully closes the needle 4 of the nozzle 12, 14 by operating the pressure oil switching valve in response to a command from the speed governor. Note that if the water turbine output becomes larger than the water injection flow rate when the nozzle 11.13 is fully open, the pressure oil switching valve is activated to enable the operation of the needle 4 of the nozzle 12.14, and the nozzles 11.13 and 12.14 are activated.
and each needle 4 are opened at the same time.

Note that when the load suddenly decreases, the deflector 15 operates rapidly in response to a command from the speed governor to prevent the water jetted from the nozzle from hitting the bucket 2.

With such a configuration, when the load is smaller than the sum of the water injection flow rates of the nozzles 11 and 13 when the needle nozzles are fully opened, the hood is connected to the pressure regulating valve 21 connected to the speed governor.
The deflector servo motor 18 is operated via the deflector servo motor 18, and the deflector 15 is rotated in accordance with the load, and the needle 4 of the nozzle 11.13 is moved by pressure oil from the deflector pressure distribution valve, and the needle nozzle opening degree is adjusted. Water at a flow rate corresponding to the load is injected from the nozzle 11.13, and a water turbine output corresponding to this injection flow rate is obtained, and a generator connected to the runner 3 via a shaft outputs electric power according to the water turbine output. do.

If the load increases further and becomes equal to or greater than the sum of the water injection flow rates of nozzles 11 and 13 when the needle nozzles are fully open, the pressure distribution valves will be used to distribute the pressure to each needle 4 equally. Water is injected from each nozzle by adjusting the opening of the nozzle, and the turbine output corresponding to the injection flow rate is obtained to cope with the increasing load.

Figure 4 shows nozzles 11.13 and 12.14 when the water turbine output exceeds the output corresponding to the needle opening of nozzles 11 and 13 (the stroke of the needle servo motor) when fully open.
In Figure 0, which is a graph showing the needle opening of nozzles 11 and 13, when the needle opening of nozzles 11 and 13 is fully open (100%) and the output is further increased at point A, nozzles 11 and 1
3 in the closing direction as shown at 30, nozzle 1
The needles 2 and 14 are moved in the opening direction as shown in 31, and the needles 4 of nozzles 11.13 and 12.14 are made to have the same opening degree, and from point B when the needles 4 of nozzle 11.13 and nozzle 12.14 are at the same opening degree, The needles 4 of the nozzles 11 to 14 are operated at the same time at the same opening rate to inject an equal flow rate of water from each nozzle to cope with the increase in output. The water turbine output at this time becomes the output state shown in 32.

[Problem to be solved by the invention]

As mentioned above, when the water turbine output increases beyond the output corresponding to the pulse of the water injection flow rate when the needle nozzles of nozzles 11 and 13 are fully opened and water is injected from other nozzles 12 and 14, nozzle 11 and The switching method is to set the needle openings of nozzles 12 and 13 in the closed direction and the needle openings of nozzles 12 and 14 in the open direction, and then set the needle openings of these nozzles to the same opening, and then increase the output at the same opening ratio. , it takes time to switch the needles of each nozzle to the same opening degree, and the fourth
As shown in the figure, during this switching time (time from point A to point B), the water turbine output fluctuates like 33. This is the needle nozzle opening corresponding to the water injection flow rate and the needle servo motor's stroke by one dollar opening ) is not a linear proportional relationship as shown in FIG. In other words, this is because the water injection flow rate is not constant.

There is a problem with doing so.

An object of the present invention is to provide a nozzle switching method for a Pelton water turbine that can eliminate switching time and fluctuations in the water turbine output when the number of nozzles is switched as the water turbine output increases.

[Means to solve the problem]

In order to solve the above problems, the present invention includes a runner having a bucket on the outer periphery, a plurality of pairs of nozzles arranged opposite to each other around the launch, and water inserted into the nozzle and jetted from the nozzle. A method for switching nozzles of a Pelton water turbine, which switches the logarithm of a nozzle that injects water according to an increase or decrease in the output of the water turbine, in a Pelton water turbine equipped with a needle that controls the opening degree of the nozzle, which determines the flow rate, and an increase in the output. When the nozzle opening of one pair of nozzles becomes fully open, the needle nozzle opening of the other pair of nozzles is controlled to increase the water injection flow rate.On the other hand, when the output decreases, the flow rate of water is increased by reversing the above procedure. Each time the needle nozzle opening of a nozzle becomes fully closed, the needle nozzle opening of another pair of nozzles is controlled to reduce the water injection flow rate.

[Effect]

In a Pelton turbine that has multiple pairs of nozzles arranged facing each other facing the runner, the turbine output increases, and a water injection flow rate greater than the water injection flow rate when the needle nozzle opening of the pair of nozzles is fully opened is required. If so, leave the needle nozzle opening of this pair of nozzles fully open and operate the needles of the other pairs of nozzles to control the needle nozzle opening and inject the water injection flow rate corresponding to the output from each nozzle. . That is, when the needle nozzle openings of a pair of nozzles become fully open, the needle nozzle openings of the other pair of nozzles are controlled to increase the water injection flow rate.

On the other hand, when the output decreases, the above procedure is reversed. In other words, when the output needs to be further reduced than the water injection flow rate of a pair of nozzles controlling the water injection flow rate, after the needle nozzle opening of this nozzle is fully opened, the other pair of nozzles that are fully open are The opening degree of the needle nozzle is controlled by the needle, and the water injection flow rate corresponding to the reduced output is injected from each nozzle. That is, when the nozzle with the seal is fully opened, the opening degrees of the needle nozzles of the other pair of nozzles are controlled to reduce the water injection flow rate.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a control system diagram of a Pelton turbine to which a nozzle switching method according to an embodiment of the present invention is applied. In FIG. 1, parts that are the same as those in the conventional example shown in FIG. 3 are designated by the same reference numerals, and their explanations will be omitted. What is different from the conventional example in FIG. 1 is the provision of a pressure regulating valve 40 that controls the stroke of the needle 40 of a pair of nozzles 11 and 13, and a pressure regulating valve 41 that controls the stroke of the needle 4 of the other pair of nozzles 12 and 14. ,
Pressure oil supply pipe 4 from ports 42 and 43 of pressure distribution valve 40
4.45 are respectively connected to the oil chambers on both sides of the piston 19 of the deflector servo motor 18 of the nozzle 11.13, while the pressure regulating valve 41 is connected to the port 46.47 of the nozzle 12.14 and the piston 19 of the deflector servo motor 18 of the nozzle 12.14. It is connected to the oil chambers on both sides with pressure oil supply pipes 48 and 49. In addition, the pressure distribution valve 4
0.41 is controlled by a command from a speed governor (not shown).

With this configuration, when the Pelton turbine is driven and the load is small, the needle of the nozzle 11.13 is operated by operating the pressure distribution valve 40, the needle nozzle opening degree is controlled, and water is injected from the nozzle 11.13 in accordance with the load. inject the flow rate,
A water turbine output corresponding to this injection flow rate is obtained. Then, when the load increases further and the needle nozzle opening degree of nozzle 11.degree.
Fully open needle nozzle 13, and then open pressure distribution valve 4.
1, the needle nozzle opening degree of the nozzle 12.14 is controlled by operating the needle 4, and the controlled needle nozzle opening degree of the nozzle 12.14 and the nozzle 11.13 are
A water injection flow rate corresponding to the fully open needle nozzle opening is injected, and a water turbine output corresponding to this injection flow rate is obtained.

On the other hand, when the load decreases, the pressure regulating valve 4 is
1, the needle nozzle opening of the nozzle 12.14 is reduced to reduce the water jet flow rate from the nozzle 12.14. Then, the load further decreases and the nozzle 11.13
When the load corresponds only to the water injection flow rate from , controls the water injection flow rate from the nozzles 11 and 13, injects the water injection flow rate corresponding to the reduced load from the nozzle IL13, and obtains the water turbine output corresponding to this injection flow rate.

Figure 2 is a graph showing the above nozzle switching. In Figure 0, which will be further explained based on the figure, when the needle opening of nozzle 11.13 is fully open (100%), that is, the water turbine output is 5094 output. When the water turbine output increases from the state to point C, the needle opening of nozzle 11.13 remains fully open, and the water injection flow rate is increased by sequentially changing the needle opening of nozzle 12.14. Along with this, the water turbine output is 50
Increases sequentially from % output. Then, at point D when the needle opening of nozzle 12.14 is fully opened, the water turbine output is 100%.
becomes the output. When reducing the output from such a state, the needle opening of nozzle 12.14 is decreased from time E while keeping the needle opening of nozzle 11.13 at 100%, and if the needle opening of nozzle 12.14 is fully opened at time F, the water turbine output will be At point F, the output becomes 50%.

When the water turbine output is further decreased from this point F, the needle opening degree of the nozzle 11.13 is decreased, and if it is fully opened at the zero point, the water turbine output becomes O.

By switching the nozzles in this way, when the number of nozzles is increased or decreased according to an increase or decrease in the output of the water turbine, a pair of nozzles 11.
13 and 12. Since the needle opening is controlled independently of 14, there is no output fluctuation based on the non-linear relationship between the nozzle needle opening and the needle servo motor stroke (needle opening) as in the past. .

Although the nozzle switching method for a 4-nozzle Pelton turbine has been described above, the same nozzle switching method as described above can be applied to the 2-nozzle operation H4 nozzle operation → 6-nozzle operation in a 6-nozzle Belton turbine.

(Effects of the Invention) As is clear from the above description, according to the present invention, in a Pelton turbine consisting of a plurality of pairs of nozzles, when the turbine output increases, after the needle nozzle opening degree of the pair of nozzles becomes fully open, By increasing the needle nozzle opening of the other pair of nozzles in this fully open state, and switching the nozzle in the reverse procedure to the above when decreasing, each pair of nozzles can independently open the needle nozzle. Since the water injection rate is controlled and injects a water injection flow rate corresponding to the output, there is no fluctuation in the output when changing the nozzle to increase or decrease the turbine output. stable power can be supplied to the power grid even when Also, when switching nozzles, there is no need to make the needle nozzle opening of each nozzle the same.
This also has the effect of eliminating switching time.

[Brief explanation of drawings]

FIG. 1 is a control system diagram of a Pelton turbine to which the nozzle switching method according to the embodiment of the present invention is applied, FIG. 2 is a diagram showing the needle opening process and the water turbine output process according to the nozzle switching method in FIG. Figure 4 is a control system diagram of a Pelton turbine using the conventional nozzle switching method, Figure 4 is a diagram showing the needle opening process and turbine output process using the nozzle switching method shown in Figure 3, and Figure 5 is a diagram showing the flow of the turbine output process using the nozzle switching method shown in Figure 3. FIG. 3 is a diagram showing the relationship between needle nozzle opening and needle servo motor stroke. 2: Bucket, 3: Runner, 4: Needle, 11.12
, 13, 14: nozzle, 21, 40, 41: pressure distribution valve.

Claims (1)

[Claims] 1) A runner having a bucket on its outer periphery, a plurality of pairs of nozzles arranged facing each other around the runner, and a needle inserted into the nozzle to control the opening degree of the needle nozzle, which determines the flow rate of water injected from the nozzle. A nozzle switching method for a Pelton water turbine that switches the logarithm of the nozzle that injects water according to an increase or decrease in the output of the water turbine in a Pelton water turbine equipped with Each time the nozzle is fully opened, the needle nozzle opening of the other pair of nozzles is controlled to increase the water injection flow rate.On the other hand, when the output decreases, the needle nozzle opening of the pair of nozzles is fully closed by reversing the above procedure. A nozzle switching method for a Pelton turbine, characterized in that the opening degree of the needle nozzle of the other pair of nozzles is controlled to reduce the water injection flow rate each time the needle nozzle of the other pair of nozzles is opened.