JPH0133667B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for controlling a Pelton turbine,
Especially in hydroelectric power plants equipped with Pelton turbines,
When power generation is stopped due to a system failure, etc., the operation of the turbine is stopped by operating only the deflector with the needle fully open, allowing natural discharge, and then when re-paralleling with the grid, the natural discharge flow rate can be paralleled without changing. This paper relates to a control method for a Pelton turbine that enables the following.

[Conventional technology]

Generally, Pelton turbines are impulse turbines that are used at high head sites of 200 to 1,800 m, and horizontal shaft types are used for medium-capacity machines and smaller, and vertical shaft types are used for large-capacity machines.
To explain the outline using the horizontal axis type Pelton turbine shown in Fig. 1, pressurized water from a penstock 10 is distributed to two nozzles 1 and 2 by an inlet curved pipe 11a and 11b. The jets are accelerated and become high-speed jets 12a and 12b, which apply water power to the bucket 5a to perform work and are then discharged into the lower discharge channel 14. During normal operation, the needles 1a and 2a in the respective nozzles 1 and 2 are opened and closed according to the load by their respective servo motors 1c and 2c to adjust their flow rates. Each nozzle 1, 2
Deflectors 1a and 2b are rotatably provided between the nozzle and the runner 5, and when the load suddenly decreases, a servo motor 6 moves the deflectors 1b and 2b through a link mechanism 7.
b are interlocked and rotated at the same time to temporarily divert the direction of the jet from the direction of the bucket cart 5a, during which time each needle 1a, 2a is gradually closed to suppress an increase in the number of revolutions in the penstock. Further, by fully opening the deflectors 1b and 2b, the direction of the jets 12a and 12b is changed to the direction of the bucket jet 5.
Although the rotation of the runner 5 completely stops from a, the water discharge can continue even when the water wheel is stopped. In addition, compared to Francis turbines, Pelton turbines can be operated by increasing or decreasing the number of jets jetted from the nozzle depending on the load, so they have high partial load efficiency.Furthermore, the runners are easy to inspect and replace, and the mechanism is simple. Because of this, it is easy to replace parts that are worn out and corroded by earth and sand, and in addition, the use of deflectors and jet brakes has advantages such as a small increase in speed and water pressure. As mentioned above, it is known to use a deflector as a control method for this type of Pelton turbine, but in the past, as shown in Figure 2, which shows the main parts of a Pelton turbine used in this control method, a plurality of deflectors (such as In the conventional example, there are four nozzles 1,
2, 3, and 4 have respective deflectors 1b,
2b, 3b, 4b are interlocked via a link mechanism 7 to form respective deflectors 1b, 2b, 3b, 4b.
These deflectors are controlled by a single servo motor 6 provided in common to both, thereby simplifying the device and balancing the water power applied to the bucket by the jet from each nozzle when the deflector is rotated. Therefore, in this method, in order to increase the speed of the water turbine from stopping to the rated rotation speed after paralleling is canceled and re-paralleling the water turbine to the grid, as is well known, each nozzle must be operated by the respective servo motors 1c, 2c, 3c, and 4c. Drive the needles 1a, 2a, 3a, and 4a to fully close the aperture, then open each needle and each deflector to the starting opening to increase speed, and then close each needle and each deflector. When the turbine rotation speed reaches the rated rotation speed n ₀ , parallel connection to the grid is performed again. This control diagram is shown in FIG.

[Problem to be solved by the invention]

Conventional control methods involve throttling each nozzle, so changes in the flow rate in the waterway are unavoidable. Therefore, even if a hydroelectric power plant using this type of Pelton turbine control method becomes unable to generate power due to a system failure or the like and continues natural discharge by operating only the deflector to ensure the discharge flow rate of the waterway system, the turbine is then started and the system is connected to the system. There is a drawback that the discharge flow rate changes when re-parallel injection is performed. In addition, as a countermeasure, it was necessary to install a spillway as a civil engineering facility to maintain the discharge flow rate, and also to install a servo tank in order to suppress the increase in water pressure in the penstock due to changes in flow rate, so it was necessary to install a servo tank. The disadvantage was that it required additional costs. This invention enables re-parallel input to the grid without changing the waterway flow rate even if power generation is stopped due to a system failure, etc., eliminates the spillway and servo tank provided as civil engineering equipment, and further improves the flow rate. It is an object of the present invention to provide a control method that eliminates increases in water pressure caused by changes and that makes penstocks inexpensive.

[Means to solve the problem]

According to the present invention, the above object is achieved by a needle that can move forward and backward, a plurality of nozzles that are opened and closed by moving forward and backward of this needle, a runner that receives the jet jet from this nozzle in a bucket and rotates by the impulse, and this runner and each nozzle. In a Pelton water turbine comprising a deflector that is pivotally supported by the nozzle and deflects the jet from the runner by rotation of the deflector between the nozzle and the runner, the deflector provided in at least one of the nozzles is driven separately from the other deflectors. When re-paralleling the generator connected to the Pelton turbine and the grid after the parallel connection is released,
This is achieved by a method for controlling a Pelton water turbine, in which the at least one deflector is driven by the means to control the rotation speed of the water turbine. Furthermore, it is preferable to use a servo motor as the driving means.

[Effect]

At least one of the nozzles is provided with a means for driving the deflector of this nozzle separately from the other deflectors, and the at least one deflector is driven by the means while the needle is kept fully open and the other deflectors are kept fully closed. The rotation speed of the water wheel can be controlled by driving the deflector.

【Example】

Embodiments of the present invention will be described below based on the drawings. FIG. 4 is an explanatory diagram of the main parts of a Pelton turbine used in the control method according to the embodiment of the present invention, and FIG. 5 is a control diagram according to the embodiment of the present invention. In FIGS. 4 and 5, the same parts as in FIGS. 1, 2, and 3 are given the same numbers, and their explanations will be omitted. The difference in Fig. 4 from Fig. 2 is that the four deflectors 1b, 2b, 3b, 4b are controlled independently by servo motors 1d, 2d, 3.
d and 4d, and the link mechanism that linked each deflector was removed. In Fig. 5, when the brake is turned on, the deflector is fully closed, the water turbine operation is stopped, and discharge continues with the needle fully open, and when the parallel connection of the water turbine and the system is instructed, the No. 1 nozzle system That signal can only be transmitted. Therefore, in the No. 1 nozzle, the needle 1a is closed to the no-load opening position by the servo motor 1c, and the water turbine brake is turned off.
After opening the needle 1a and deflector 1b to the starting opening, the speed of the water turbine is increased. When both reach the starting opening, the rotation speed of both the water turbines reaches the steady rotation speed.
It closes until n ₀ , contacts the load at the rated rotation speed n ₀ , and then deflector 1b and needle 1a
At the same time, the other deflectors 2b, 3b, and 4b, which were fully closed, are fully opened to shift to full-load operation. That is, in this method, only one nozzle 1 is used to control its deflector 1b and needle 1a to control the rotation speed at the time of re-parallel injection. At normal start-up, all nozzles are operated as before, but when the parallel circuit between the generator and the grid is released and the circuit is reclosed, only one nozzle 1 is operated and the water turbine reaches its rated rotation speed. The starting opening degree and the no-load opening degree can be switched in order to increase the speed until the After starting power generation with one nozzle fully open, the other standby nozzles and deflectors are fully opened, resulting in full-load operation. Therefore, there is no need to fully close all nozzles when re-paralleling, and since the rotational speed of the water turbine is controlled by operating only one nozzle, the flow rate of the waterway hardly changes.

【Effect of the invention】

As described above, according to the present invention, a driving means including a servo motor or the like is provided which drives the deflector of at least one of the plurality of nozzles separately from the deflector of the other nozzles, and this means drives the deflector of at least one of the plurality of nozzles separately from the deflector of the other nozzles. By driving one deflector and controlling the rotation speed of the water turbine, the generator connected to the Pelton turbine and the grid are re-paralleled after being released from parallel, so when the generator is re-paralleled into the grid, the waterway Since the flow rate inside the tank hardly changes, the discharge flow rate can be maintained without installing a spillway as a civil engineering facility. Moreover, since there is no increase in water pressure caused by changes in flow rate, a surge tank can be omitted and the cost of the penstock can be reduced, which is an excellent effect.

[Brief explanation of drawings]

Figures 1, 2, and 3 show conventional examples of Pelton water turbines. Figure 1 is a vertical cross-sectional view showing its outline, and Figure 2 is an explanation of the main parts of the Pelton water turbine used in its control method. 3 and 3 are control diagrams thereof, and FIGS. 4 and 5 are explanatory diagrams of main parts of a Pelton water turbine used in an embodiment of the present invention and control diagrams thereof. 1, 2, 3, 4: nozzle, 1a, 2a, 3a,
4a: Needle, 1b, 2b, 3b, 4b: Deflector, 1d, 2d, 3d, 4d: Servo motor as driving means, 5: Runner, 5a: Bucket, 12a, 12b: Jet.

Claims (1)

[Scope of Claims] 1. A needle that can freely advance and retreat, a plurality of nozzles that are opened and closed by advancing and retreating the needle, a runner that receives jet jetted from the nozzle in a bucket and rotates by the impulse, and a space between the runner and each nozzle. A Pelton water turbine is provided with a deflector which is pivotally supported by the nozzle and whose rotation deflects the direction of the jet from the runner, wherein at least one of the nozzles is provided with means for driving the deflector of this nozzle separately from other deflectors. , when re-paralleling the generator connected to the Pelton turbine and the system after the parallelization is released, the at least one
A method for controlling a Pelton water turbine, characterized in that the rotation speed of the water turbine is controlled by driving two deflectors. 2. A method for controlling a Pelton water turbine according to claim 1, wherein the driving means is a servo motor.