JP2822184B2 - Pelton turbine control unit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a Pelton turbine in a hydroelectric power plant, and particularly to a small- to medium-sized hydroelectric power plant in which a spillway and a spillway connected thereto are omitted. The present invention relates to a control device for a Pelton turbine suitable for the present invention. [Prior Art] FIG. 4 shows an example of the configuration of a conventional general Pelton turbine and its control device, and the outline thereof will be described below. First, the flow of water is as follows. In FIG.
The pressurized water guided from a water tank (not shown) is guided to a curved pipe 1 and supplied to a nozzle 2. This water pressure is
As a result, a high-speed jet water stream is jetted to a bucket provided on the outer periphery of the runner 3. The runner 3 rotates by the action of the impact force of the jet water flow, and a generator (not shown) connected to the runner 3 is turned to finish the work. The gushing water is discharged to the tailrace. The deflector 6 adjusts the rotation speed of the runner 3 by adjusting the flow rate of the jet water flow. In the above configuration, the speed control of the conventional Pelton turbine mainly adjusts the opening degree of the deflector 6, and generally adjusts the opening degree of the needle of the nozzle 2 following the adjustment. Therefore, the control system is roughly divided into a deflector control system and a needle control system. In the deflector control system, an electric signal from the speed governor 9 is converted into a mechanical output by the converter 10, and the mechanical output drives the pressure distribution valve 11 through the spool 11a. The pressure oil from the pressure distribution valve 11 drives the piston 7a of the deflector servomotor 7 through the pipelines 22a and 22b, and the driving force rotates the deflector 6 via the rod 8 and the arm 6a. In this manner, the opening degree of the deflector 6 is adjusted by the speed control signal from the speed governor 9, the jet water flow from the nozzle 2 corresponding to the opening degree is deflected, and the runner 3 rotates at a desired speed. Reference numeral 12 denotes a return device for performing feedback control of the opening of the deflector 6, and a detection signal thereof is input to the speed governor 9. Next, in the needle control system, the operation amount of the deflector 6 is transmitted to the tracking cam 13 via the arm 6a and the link mechanism, and the rod 14a of the needle pressure distribution valve 14 is driven forward and backward by following the rotation of the tracking cam 13. I do. By this forward / backward drive, the pressure oil is supplied to the needle servomotor 5 through the pipes 21a and 21b.
Acts on the piston 5a. A rod 4a is connected to the piston 5a, and the reciprocating motion of the rod 4a causes the needle 4 inserted through the axis of the nozzle 2 to reciprocate, thereby changing the opening area of the tip of the nozzle 2 and adjusting the ejection flow rate. It has become. Reference numeral 17 denotes a spring for pressing the roller 16 against the tracking cam 13, and reference numeral 18 denotes a return shaft for feeding back the position of the rod 4a. As described above, the speed control at the time of increasing (or decreasing) the speed of the water turbine is performed by deflecting the jet water flow from the nozzle 2 by adjusting the opening degree of the deflector 6, and on the other hand, following the movement of the deflector 6. By reducing (or increasing) the opening of the needle 4, the rotation speed of the water turbine is controlled within a specified value. [Problems to be Solved by the Invention] As described above, the speed control of the conventional Pelton turbine mainly performs the deflector, and controls the needle following the deflector. In this case, when the load is cut off at the power plant, first, the deflector 6 is suddenly closed to control the speed rise of the runner 3, and then the needle 4 is slowly closed to a position determined by the relative relationship with the deflector 6. Automatic control can be performed according to the load fluctuation. However, the problem here is that when the spillway and the spillway connected to the spillway are omitted in order to reduce the construction cost of the power plant, the above-described conventional control device is caused by closing the needle. The spill water cannot be discharged smoothly,
Since the water in the headrace is filled with water, the headrace must be a pressure tunnel, which does not contribute much to reducing the construction cost. Therefore, an object of the present invention is to provide a control device for a Pelton turbine that can smoothly control spillage and arbitrarily control the speed of a water turbine in a hydroelectric power plant in which a spillway is omitted. [Means for Solving the Problems] To achieve the above object, a control device for a Pelton turbine of the present invention has a runner rotating with a plurality of buckets on the outer periphery and a needle capable of adjusting the opening degree. A nozzle that changes the water guide from the water tank to the jet water stream to the bucket and jets the jet water; anda deflector that is provided between the bucket and the nozzle and that can adjust the opening degree to deviate the jet water flow. In a control device for a Pelton turbine driving a connected generator, a water level adjuster for inputting a water level signal of a water tank and outputting a needle opening control signal, and a deflector opening control signal for inputting a speed signal of a turbine and inputting a speed signal of the turbine. And a speed governor that outputs the same.When the generator is connected to the power system, the operation of the needle is controlled on condition that the water level of the water tank is within a predetermined control value. It is characterized in that the water flow acting on the runner is fixed only by the deflector and fixed. [Operation] According to the configuration of the present invention, the water level adjuster controls the needle opening of the nozzle based on the water level of the water tank irrespective of the opening of the deflector, so that even when spillage occurs, the water level adjuster can quickly perform this operation. From the nozzle. On the other hand, since the speed governor adjusts the opening of the deflector based on the rotation speed of the turbine, even if the rotation speed increases due to the increase in the flow rate of the jet from the nozzle due to the increase of the residual water, the needle opening is not The turbine can be controlled to the specified speed without any direct involvement. In this way, it is possible to appropriately control the rotation speed of the water turbine while smoothly discharging the sewage in the hydroelectric power plant in which the spillway is omitted. When the generator is connected to the power system, the operation of the needle is fixed and the flow of water acting on the runner is adjusted only by the deflector, provided that the water level in the water tank is within a predetermined limit value. The rotation speed can be finely adjusted in the state of the amount, and the aligning speed and the parallel operation to the system frequency can be easily and quickly performed. Embodiment Next, an embodiment according to the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In FIG. 1, parts that are the same as in FIG. 4 (conventional example) are given the same reference numerals, and detailed descriptions thereof are omitted. The difference between this embodiment and the conventional example is that the control system of the needle 4 and the control of the deflector 6 are configured independently of each other. That is, as can be seen by comparing FIG. 1 and FIG.
Does not have a follow-up interlocking mechanism consisting of
A return device 23 for feedback is linked to a return shaft 18 attached to the rod 4a, and an output signal thereof is input to a water level adjuster 19. Water level regulator 19
Outputs a control signal to the converter 20 for adjusting the water level change based on the detection signal ΔH of the water level transmitter 26 provided in the water tank 27 as described later in FIG. Converter 20 converts a control signal from water level adjuster 19 into a mechanical output, and drives spool shaft 14a. Then, the needle pressure distribution valve 14 is switched to send pressure oil to the needle servomotor 5 through the pipelines 21a and 21b, and the opening of the needle 4 is adjusted. Next, the control operation will be described. FIG. 2 shows a block diagram of a needle control system and a deflector control system according to the present embodiment, and FIG. 3 shows operation waveforms of respective parts. First, when the power plant is in a stop state, the stop signal 0 is input to the water level adjuster 19, so that the water level adjuster 19 does not output a control signal, and the needle 4 is fully closed, that is, the needle is open. The degree Fn is 0 (FIG. 3 (d)). on the other hand,
The speed governor 9 as a speed adjusting device has an opening set value Fe
= 0, the deflector 6 is also in the fully closed state, that is, the deflector opening Fd is also 0 (FIG. 3 (e)). When the power plant start command A is given and the intake gate opening command is issued, the intake gate (not shown) starts to open (FIG. 3 (a)). The withdrawn water arrives at the water tank 27,
When the water level 27 rises and reaches the operable water level (FIG. 3 (c)), a turbine start command B is issued. The water level in the water tank 27 is detected by a water level oscillator 26. The operation command P is input to the water level adjuster 19 in place of the stop instruction 0, whereby the water level adjuster 19 starts the control operation. The water level adjuster 19 outputs a needle opening control signal corresponding to the water level fluctuation ΔH based on the detection signal from the water level oscillator 26. This control signal is given to the needle 4 via the converter 20, the pressure distribution valve 14, and the needle servomotor 5. The needle 4 is opened to an opening corresponding to the water level fluctuation ΔH (FIG. 3 (d)), and a corresponding flow of pressure water is jetted from the nozzle 2. On the other hand, at this time, the opening set value Fe input to the speed governor 9 is set as the starting opening, and the opening of the deflector 6 is opened to the starting opening (FIG. 3 (e)). Thus, the turbine is started, and the rotation speed N of the turbine increases toward the specified speed (FIG. 3 (f)). When the rotation speed N of the water turbine substantially reaches the specified value (FIG. 3E), the speed governor 9 starts speed control. The speed governor 9 outputs a control signal for correcting the speed fluctuation ΔF based on a detection signal from the speed detector. Converter 10
Converts the control signal into a mechanical output and adjusts the opening of the deflector 6 through the pressure distribution valve 11 and the deflector servomotor 7 (FIG. 3 (e)). The jet water flow determined by the opening degree of the deflector 6 is deflected to the bucket of the runner 3 to act, and the other surplus water is discharged to the discharge path. This discharge is called deflector discharge. In this way, the turbine and the rotation speed N are controlled to be constant so as to be the specified values. During this time, the needle 4 is controlled so as to open as the water level of the water tank 27 rises. However, the water level of the water tank 27 is within the limit value in order to insert the generator connected to the turbine into the power system in parallel. Is locked (see L in FIG. 3D). This locking is performed by a lock signal L to the water level adjuster 19. This lock is arranged in parallel with the frequency of the system with a stable power generation amount. That is, the locking of the needle is performed in the process of aligning the speed of the spontaneous generator to the system frequency and paralleling the system.
At the time of parallel operation, it is necessary to adjust the water flow acting on the runner and control the difference between the frequency (rotation speed) of the turbine generator and the system frequency within 1 / 4HZ or 1 / 8HZ. On the other hand, in order to keep the water level of the water tank constant, the needle 4 controls the flow rate in accordance with the rise and fall of the water level of the water tank, and the director 6 controls the water flow acting on the runner 3. In operation requiring such intense frequency control,
In the above-described needle control, the water flow acting on the runner 3 changes in accordance with a change in the needle opening (a change in the opening due to a change in the water level of the water tank). Is required. For this reason, the water flow from the needle 4 is kept constant during the system parallel operation, and the water flow acting on the runner is adjusted only by the deflector 6 to easily and quickly perform the uniforming speed and the parallel operation. Lock. When the parallel charging to the power system is completed, the lock signal L for the needle 4 is released, and the water level adjustment operation is started again. At the same time, the deflector 6 is operated to the fully opened position (third opening).
(E), the power transmission operation according to the flow rate of the pressure water is performed. Next, the operation when the load suddenly changes will be described. When the load suddenly decreases due to an accident or the like occurring in the electric power system during normal operation and the rotation speed N of the water turbine rapidly increases (see E in FIG. 3 (f)),
The speed governor 9 rapidly closes the deflector 6 (FIG. 3 (e)), and suppresses an increase in the rotation speed N. Subsequently, the operation is continued while maintaining the specified speed stably at the deflector opening at that time. When the accident is recovered and the power transmission is restored, the state is set to re-parallel G, the deflector 6 is opened, and the power transmission is resumed. Control for adjusting the water level of the needle 4 is continued in accordance with the inflow flow rate. The rotation speed N is detected by a rotation speed detector 33 provided on the main shaft 32 of the runner 3. On the other hand, when a sudden stop command M is issued due to an internal accident or the like in the power plant, the deflector 6 is suddenly closed by setting the opening degree set value Fe to 0 (FIG. 3 (e)), and the turbine is shifted to stop. . At the same time, a closing command is issued to the intake gate to close the intake gate (FIG. 3 (a)). However, abrupt closure of the intake gate may cause a sudden rise in river water level, so the gate should be closed slowly. If it is slowly closed, the water will continue to flow into the water tank 27 for that time. Then, the needle 4 is kept open while the deflector 6 is fully closed and the pressure water to the runner side is all deflected to the water discharge channel side.
Continue to discharge water from. When the water level in the water tank 27 reaches the stop water level, a stop command 0 is input to the water level adjuster 19 to fully close the needle 4 (FIG. 3 (d)). As described above, in a hydroelectric power plant in which the spillway is omitted, the spill water is discharged from the nozzle 2 by controlling the needle 4 so that the water level of the water tank 27 is always equal to or lower than the specified water level. The speed can be controlled to a desired value. In FIG. 2, the outputs of the needle 4 and the deflector 6 are given to the runner 3 with the low value priority 28 as follows. That is, the water flow acting on the runner 3 is deflected by the deflector 6 until the turbine enters the system.
After being inserted into the system, the deflector 6 is held at the fully open position, and the water flow is adjusted by the needle 4. Since a flow rate smaller than the flow rate flowing into the water tank 27 may be sufficient from the start of the turbine generator to the parallel insertion, a part of the water flow injected from the needle 4 acts on the runner 3 and the rest is blocked by the deflector 6. After the paralleling, the deflector 6 is held at the fully open position,
The water flow acting on the runner 3 is regulated only by the needle 4. In other words, when this is viewed from the opening degree of the deflector 6 and the needle 4, the water flow corresponding to the smaller opening of the needle 4 and the deflector 6 is always used for the runner 3, and the lower value always has priority. Because. In addition, the rotating body time constant in FIG. 2 is a deviation (△ F) between the speed setting value (or system frequency) and the rotating body frequency.
Indicates that the time appears due to the difference between the generator output 29 and the load 30, which increases or decreases according to the magnitude of the water flow acting on the runner 3, and the inertia (time constant of the rotating body) held by the rotating body. In addition, the speed control operation of the water turbine is performed by the deflector 6,
Since the operation is controlled separately from the operation of the needle 4, there is no fluctuation in water pressure caused by the opening and closing operation of the needle 4,
It is possible to stabilize the rotation speed of the water turbine in a short time, thereby enabling independent operation with good control responsiveness, and enabling parallel input to the power system in a short time. In addition, since the needle opening degree is controlled in accordance with the flow (or water level) of the water flowing into the water tank 27, the load operation can be shifted in a short time by opening the deflector 6. [Effects of the Invention] As described above, according to the present invention, a water level adjuster that controls a needle opening degree according to a water tank water level, and a speed governor that controls a deflector opening degree according to a rotation speed of a runner. Independently installed spillway, spillage generated in the water tank in a hydroelectric power plant with no spillway can be performed smoothly and reliably without impairing the speed controllability of the Pelton turbine. Can be achieved. When the generator is connected to the electric power system, the operation of the needle is fixed and the water flow acting on the runner is adjusted only by the deflector, provided that the water level in the water tank is within the limit value. Speed and parallel operation can be performed easily and quickly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a Pelton turbine and its control system showing an embodiment of the present invention, FIG. 2 is a block diagram showing details of the embodiment of the present invention, and FIG. FIG. 4 is a time chart showing operation waveforms, and FIG. 4 is a configuration diagram of a conventional control system. 2 ... Nozzle, 3 ... Runner, 4 ... Needle, 5 ...
Needle servo motor, 6 ... deflector, 7 ... deflector servo motor, 9 ... speed governor, 11 ... pressure distribution valve, 14 ... pressure distribution valve, 27 ... water tank.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F03B 15/20

Claims (1)

(57) [Claims] A runner rotating with a plurality of buckets on its outer periphery,
A nozzle that has a needle whose opening can be adjusted and that jets water from the water tank into the bucket by changing the water into a jet stream,
An opening-adjustable deflector provided between the bucket and the nozzle and configured to deviate the shet water flow,
In a Pelton turbine control device that drives a generator maintained in an electric power system, a water level adjuster that receives a water level signal of a water tank and outputs a needle opening control signal and a deflector that receives a speed signal of a water turbine and inputs a speed signal of the turbine. A speed governor that outputs a degree control signal is provided independently.When the generator is connected to the power system, the operation of the needle is fixed and only the deflector is provided, provided that the water level of the water tank is within a predetermined limit value. A control device for a Pelton turbine, wherein a water flow acting on a runner is adjusted by the above method.