JPH0324590B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a method for operating a Pelton turbine in a run-of-river power plant in which a spillway is omitted.

[Problems with conventional technology]

Figure 2 shows an overview of the main structural parts of a Pelton turbine. In FIG. 2, a water conduit 31 that leads water from a head tank (not shown) has a plurality of branch pipes 3.
2, 32a are provided. Branch pipes 32, 32
Needle shafts 33a each having a needle 33 at its tip pass through bent pipes 34, 34a, are supported by bearings (not shown) provided on nozzle pipes 35, 35a, and are reciprocated by a drive device (not shown). be done. The needle 33 is moved to the nozzle 3 by the reciprocating movement of the needle shaft 33a.
6, 36a, the opening of the nozzle is adjusted, and the water flow from the head tank is jetted out as a jet water stream at this opening. This jet water flow hits a large number of buckets 37a provided on the runner 37, causing the runner 37 to rotate in the direction of the arrow. Then, a generator connected to the shaft 37b of the runner 37 can be driven to extract electric power.

The deflector 38 is rotatably provided to cover the nozzle, and a deflector tracking controller allows the needle and the deflector to have an optimal position due to the correlation characteristics between the needle and the deflector. The deflector covers the nozzle so as to change the direction of jet water jetted from the nozzle when the system is shut off, thereby preventing an abnormal increase in the rotational speed of the runner and a sudden pressure increase in the penstock. In a Pelton turbine in a run-of-river power plant, a water level regulator is installed in the head tank, and the opening of the needle and nozzle is adjusted according to the water level, and electric power corresponding to the jet water jet ejected from this opening is sent to the generator via the runner 37. The water is taken out and a so-called water conditioning operation is performed. In this case, the frequency of the generator is the frequency of the connected power grid.

In addition, a frequency setter, a controller, etc. are provided to set and control the rotation speed of the Pelton water turbine, and the rotation speed of the water turbine during no-load operation when disconnected from the power grid is set and controlled.

In the water control operation of the Pelton turbine as described above, when the system is cut off from the power grid, the deflector is suddenly closed and the direction of the jet water jetted from the nozzle is changed to prevent it from hitting the bucket of the runner, thereby reducing the rotational speed of the runner. We are trying to suppress the rise and also close the needle.

Next, a conventional Pelton water turbine control circuit for water control operation will be explained. FIG. 3 is a circuit diagram of the main part of the control circuit of the Pelton turbine. In Fig. 3, the needles provided in the two groups of branch pipes are reciprocated by servo motors 1 and 1a which are respectively adjusted by opening adjusters 2 and 2a, and are inserted into and withdrawn from the nozzles to adjust the opening of the needles. The opening degree is detected by opening degree detectors 3 and 3a, respectively. The deflector is adjusted by an opening adjuster 5 and rotated by a servo motor 4 so as to cover the nozzle.
The opening degree is detected by an opening degree detector 6 that indicates the opening degree.

The water level adjustment opening setting device 7 which adjusts the water level is controlled by the water level of the head tank that supplies water to the Pelton turbine, and the detected opening from the opening detectors 3 and 3a is fed back to the servo motor 1 by adders 8 and 8a. 1a controls the reciprocating movement of the needle. Further, the detected opening from the deflector opening detector 6 is fed back to the adder 9 via the deflector tracking controller 10, and the servo motor 4 controls the opening of the deflector.

On the other hand, the frequency setter 11 for setting and controlling the rotation speed of the runner during no-load operation disconnected from the power grid is connected to the PID controller 14 via adders 12 and 13.
One side is connected to the servo motors 1 and 1a through adders 8 and 8a, and the other side is connected to the servo motor 4 through a deflector tracking controller 10 and an adder 9. An adder 13 calculates the detected opening from the opening detectors 3 and 3a, and feeds this back to the adder 13 via a rigid reciprocating original controller 16. Note that the detected frequency from the frequency detector 17 is fed back to the adder 12.

In the control circuit as described above, in the water adjustment operation of the Pelton turbine, the water level adjustment opening setting device 7 that adjusts the water level in the head tank controls the opening of the needle so that the water level in the head tank is adjusted by the servo motors 1 and 1a. The water that is held and sent to the branch pipe is ejected from this opening as a jet water stream. This jet water flow hits the runner's bucket, and electricity is extracted from the generator according to the amount of water being sent.

On the other hand, the optimal position of the needle and deflector of the deflector is maintained by a deflector tracking controller, and the deflector is rotated and positioned by a servo motor 4.

When a system interruption occurs and the rotational speed of the runner increases, the frequency detector 17 detects the increase in rotational speed, and by the action of the PID controller, the deflector uses the servo motor 4 to cover the nozzle and change the direction of the jet water flow. Make sure it doesn't hit Bucket. Conventionally, the opening of the needle is simultaneously closed by the servo motors 1 and 1a.

Therefore, if the spillway is omitted in a run-of-the-river power plant that performs water control operation as described above, the flow rate in the penstock decreases due to the closure of the needle opening, and the water level in the head tank rises, causing water to flow into the headrace. is full. For this reason, the tunnel used as the headrace waterway had to be a pressurized tunnel, which caused the problem that the civil engineering costs for the tunnel were high.

[Name of invention]

In view of the above-mentioned points, it is an object of the present invention to provide a Pelton water turbine discharge operation method that can reduce the civil engineering costs for the headrace in a Pelton water turbine power plant where a spillway is omitted.

[Summary of the Invention] According to the present invention, the above-mentioned object includes a runner, a needle that can freely adjust the opening degree of the nozzle by inserting and pulling out the nozzle provided in the branch pipe, and a jet water stream spouted from the opening degree. Equipped with a deflector whose opening can be freely adjusted to change the direction; a water level adjustment opening setting device which adjusts the water level of the head tank that sends water to the electric branch pipe, a frequency setting device, a frequency detector, an adder, and a controller. A discharge operation method of a Pelton turbine, in which the opening degree of the needle and the deflector is adjusted by the water level adjustment opening setting device by a circuit consisting of the following, and the jetting of the jet water flow drives the runner; An increase in the rotation speed of the runner is detected by the frequency detector, and when a predetermined value is detected, the needle opening adjustment circuit and the deflector opening adjustment circuit are separated, and the needle opening adjustment is performed by the water level adjustment circuit. The opening of the deflector is adjusted via the frequency setting device and the controller, and the rotation speed of the runner is adjusted to the rotation speed during no-load operation while discharging from the opening of the needle. This is achieved by maintaining the

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings. FIG. 1 is a circuit diagram of a main part of a control circuit for controlling water in a Pelton water turbine according to an embodiment of the present invention.
In Fig. 1, needle servo motors 1 and 1a and an opening adjuster 2 are installed in two groups of branch pipes.
and 2a, opening detectors 3 and 3a, deflector servo motor 4, opening regulator 5, opening detector 6, water level adjustment opening setting device 7, deflector tracker 10, PID
The circuit configurations and functions of the controller 14, rigid body restoration controller 16, frequency setter 11, frequency detector 17, etc. are the same as those of the prior art, but in this embodiment, between the circuits 20 and 21 Further, a changeover switch 23 is attached to the circuit 20 and the circuit 22, which is linked to the increase in the rotational speed of the runner detected by the frequency detector 17. In this changeover switch 23, during normal water conditioning operation, the switch contact 23a is open, and both 23b and 23c are closed. When the rotational speed of the runner detected by the frequency detector 17 increases, the switch contact 23a is closed, and the switch contact 23b is closed. and 23c are both open.

Therefore, during water adjustment operation, the needle and deflector are operated as described above via the closed switch contacts 23b and 23c in response to a signal from the water level adjustment opening setting device that adjusts the water level in the head tank.
The water in the head tank is sent to the Pelton turbine while maintaining its water level.

However, when the system is cut off, the frequency detector 17 detects an increase in the rotational speed of the runner, and as described above, by opening the switch contacts 23b and 23c and closing the switch 23a, the circuits 21 and 20 and 22 and 24 are disconnected, and the circuit is disconnected. 20 and 24 are connected. Therefore, the needle is controlled by the opening adjusters 2 and 2a and the servo motor 1 according to the signal from the water level adjustment opening setting device 7.
and 1a, opening detectors 3 and 3a, rigid body restoration controller 1
The opening degree of each needle is adjusted by a circuit consisting of 6 and 6, and the water flow from the head tank is discharged at this opening degree, so that the water level in the head tank is maintained. At the same time, the deflector is set to frequency setter 1.
1. A circuit consisting of a frequency detector 17, a PID controller 14, an opening adjuster 5, a servo motor 4, and an opening detector 6 covers the jet water jet ejected from the nozzle and changes its direction to prevent abnormal rotation of the runner. In addition, by the action of the frequency setting device, PID controller, etc., the deflector maintains an opening that allows part of the jet water flow to be ejected to the runner, and maintains the set rotation speed during no-load operation. In this case, it is desirable to insert the frequency dead band controller 26 between the adders 28 and 27 to reduce the fluctuation of the deflector.

Note that the parallel connection to the power grid is immediately performed at the maintained rotation speed during no-load operation, and after the parallel connection, the changeover switch 23 can be switched to perform normal operation.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, in a run-of-river power plant equipped with a Pelton turbine without a spillway, water is discharged to adjust the water level in the head tank without closing the opening of the needle when the system is shut off. By using a deflector to control the rotation speed of the water turbine during no-load operation, it can be quickly paralleled to the power grid during system restoration, and the tunnel of the headrace does not need to be a pressurized tunnel, reducing civil engineering costs. can do.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a main part of a control circuit of a Pelton turbine in a run-of-river power plant according to an embodiment of the present invention, Fig. 2 is a partial sectional view of a main part of a Pelton turbine structure, and Fig. 3 is a Pelton turbine of a conventional run-of-river power plant. It is a principal part circuit diagram of the control circuit of a water turbine. 1, 1a: Needle servo motor, 2, 2
a: Opening degree regulator, 3, 3a: Opening degree detector, 4: Deflector servo motor, 5: Deflector opening degree adjuster, 6: Deflector opening degree detector, 7: Water level adjustment opening degree setter, 8, 8a, 9, 12, 13, 1
5, 27: Adder, 10: Deflector tracking controller, 11: Frequency setter, 14: PID controller, 1
6: Rigid body restoring controller, 17: Frequency detector, 2
3: Selector switch, 32, 32a: Branch pipe, 33
a: Needle, 36, 36a: Nozzle, 37: Runner, 38, 38a: Deflector.

Claims (1)

[Scope of Claims] 1. A runner, a needle that can freely adjust the nozzle opening by inserting and pulling out the nozzle provided in the branch pipe, and an opening that can freely adjust the opening to change the direction of the jet water flow ejected from the opening. with a deflector;
The opening of the needle and deflector is controlled by a circuit consisting of a water level adjustment opening setting device for adjusting the water level of the head tank that supplies water to the branch pipe, a frequency setting device, a frequency detector, an adder, and a controller. is adjusted by the water level adjustment opening setting device and the runner is driven by the jet of the jet water stream; the increase in the rotational speed of the runner at the time of grid interruption is detected by the frequency detector. When a predetermined value is detected, the needle opening adjustment circuit and the deflector opening adjustment circuit are separated, and the needle opening adjustment is performed via the water level adjustment opening setting device, and the deflector opening adjustment is performed via the water level adjustment opening setting device. A discharge operation method for a Pelton water turbine, characterized in that each operation is performed via the frequency setting device and the controller. 2. A discharge operation method for a Pelton water turbine according to claim 1, characterized in that the opening degree adjustment of the deflector is stabilized by a frequency dead band controller.