JPS6360226B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating a variable speed hydraulic rotary machine, and in particular to a method for operating a variable speed hydraulic rotary machine such as a generator motor or a pump connected to an electric motor, a pump water turbine, etc. under the best conditions in a wide range of operating ranges. The present invention relates to a driving method suitable for driving in a car.

In this type of hydraulic rotating machine, it is known that a law of similarity holds between the actual machine and a model having the same geometric shape. Therefore, model tests are generally conducted in a laboratory, and the performance of the actual machine is predicted from the results using the law of similarity.

FIG. 1 is a diagram showing the performance of a general model pump of a hydraulic rotary machine having guide vanes. In FIG. 1, 1 is a model-specific characteristic curve showing the relationship between the model test head Hm and the model test flow rate Qm at the model test rotational speed Nm when the opening degree of the guide vane is fixed. Further, 2 is a model efficiency (ηm) curve corresponding to the above characteristics. In the pump operation of hydraulic rotating machinery, the model head generally corresponds to the envelope curve 4 connecting the highest efficiency points of the efficiency curves above.
It is operated along the flow envelope curve 3. 5 is a model cavitation performance (σ _pri ) envelope curve corresponding to the model head-flow rate envelope curve 3.

The general formula of the above-mentioned similarity law is shown below.

H=(N/Nm・D/Dm) ² Hm...(1) Q=N/Nm(D/Dm) ³ Qm...(2) Where, N: Actual machine rotation speed Nm: Rotation speed in model test D: Representative dimensions of the actual machine Dm: Representative dimensions of the model (corresponding to D) H: Head of the actual machine Hm: Head in the model test Q: Flow rate of the actual machine Qm: Flow rate in the model test By the way, in a hydraulic rotating machine that is operated at a constant rotation speed, By setting the model test head at one point on the envelope curve 3 in Figure 1 relative to the maximum head determined by the water level conditions, the actual machine dimensions D are determined from equation (1) (Nm, Dm, and N are known). Also, as a result,
In the case of the minimum operating head, in equation (1), Nm,
Since Dm, N and D are known, the model test head corresponding to the actual minimum head can be uniquely determined from the envelope curve 3 in FIG. Therefore, the operating range specific to the hydraulic rotating machine that corresponds to the operating head of the actual machine is determined from the characteristic curve in the model test. The range indicated by the arrow x in FIG. 1 is the general operating range of the actual machine. Note that point a in FIG. 1 is the model test head equivalent to the highest head of the actual machine, and point b is the model test head equivalent to the lowest head of the actual machine, and the operating range of the actual machine is within this range. Accordingly, in conventional operation at a constant rotational speed, efficiency is lower at points other than point B, which has the highest model efficiency in Figure 1, compared to point B, and at point c, where cavitation performance is the best. When compared to , the range other than the head corresponding to this point is
This results in a disadvantage that cavitation performance deteriorates.

The present invention has been made in view of the above, and its purpose is to provide a variable speed hydraulic rotor that can be operated at a single point in terms of pump performance obtained through model tests even if the head changes depending on water level conditions. The purpose is to provide instructions on how to operate the machine.

A feature of the present invention is that a means for obtaining a rotation speed signal proportional to the square root of the head determined by the water level condition is provided, and the rotation speed signal from this means is used to control the operation at this rotation speed. be.

An embodiment of the method of the present invention will be described in detail below with reference to FIGS. 2 to 6.

FIG. 2 is a block diagram of an apparatus for explaining one embodiment of the operating method of the present invention, and shows an example in which the variable speed hydraulic rotary machine is a pump water turbine. Second
In the figure, 6 is the head H determined by the water level conditions.
This is a signal transmission that obtains a rotation speed signal that changes in proportion to the square root of the head signal from a head signal corresponding to The speed controller 7 converts the rotational speed signal into a frequency corresponding to the rotational speed at which the pump should be operated, and in the case of pump operation, controls the rotational speed of the generator motor 8 using the frequency. On the other hand, the opening degree of the guide vanes of the pump-turbine 10 is controlled via the pump-turbine speed governor 9 based on the rotational speed signal. This series of control operations will be explained in more detail using FIGS. 3 and 4.

FIG. 3 shows a diagram for explaining the equipment configuration of the pump-turbine 10 and generator motor 8 in FIG. 2, and FIG. 4 shows a diagram for explaining the equipment configuration of the pump-turbine governor 9 in FIG. The block diagram is shown below. In FIG. 3, reference numeral 22 indicates that when the water turbine is operating, water from the upper dam (not shown) is guided to the runner 21 via a conduit pipe (not shown), and when the pump is operating, the water from the runner 21 is guided to the runner 21 (not shown). 23 indicates a casing for guiding water from the runner 21 to a lower dam (not shown) through a water conduit pipe (not shown) when the turbine is operating, and a casing (23) for guiding water from the runner 21 to a lower dam (not shown) when the pump is operating. A draft tube for guiding water from the lower dam to the runner 21 is shown. The runner 21 is rotated by the water introduced from the casing 22 during operation of the water turbine, and functions to convert the potential energy of water into rotational force (torque).The runner 21 also functions to convert the potential energy of the water into rotational force (torque), and when the pump is operated, the runner 21 is rotated by water introduced from the casing 22. The rotational force used to pump water from the lower dam (not shown) to the upper dam (not shown), that is, converts the rotational force into the potential energy of the water. Reference numeral 24 indicates a guide vane, which functions to control the amount of water introduced from the casing 22 to the runner 21 when the water turbine is operating, and to control the amount of pumped water discharged from the runner 21 to the casing 22 when the pump is operating. 30 indicates a main shaft directly connecting the runner 21 and the generator motor rotor 27, which transmits the rotational force of the runner 21 to the generator motor 8 during water turbine operation, and transmits the rotational force of the generator motor 8 to the runner 21 during pump operation. work to do. In the generator motor 8, 28 represents a stator, 27 represents a rotor, and 29 represents a coil for generating rotating magnetic poles on the rotor side. In the rotational speed controller 7, the rotational speed signal proportional to the square root of the head H is converted to a frequency 37 such that the rotation of the generator motor rotor 27 coincides with the rotational speed signal, and is input to the coil 29. That is, in the coil 29,
Rotating magnetic poles are generated such that the rotational speed of the generator motor rotor 27 is proportional to the square root of the head H.

Next, the function of the pump water wheel governor 9 will be explained using FIG. 4. 41 is a signal converter for converting an electrical signal into a mechanical signal; 42 is a primary pressure distribution valve for controlling the inflow and discharge of pressure oil from an auxiliary servo motor 43 operated by hydraulic pressure; 44 and 45;
are the speed regulating rate device and the damping device, respectively, and 4
Reference numeral 6 indicates a secondary pressure distribution valve for controlling the inflow and discharge of pressure oil from the main servo motor 31 operated by hydraulic pressure.
The servo mechanism formed by the secondary pressure distribution valve 46 and the main servo motor 31 serves as a signal amplification mechanism for the servo mechanism formed by the primary pressure distribution valve 42 and the auxiliary servo motor 43. It is opened and closed by the main servo motor 31.

Next, the specific control operation during pump operation will be explained. The signal (electrical signal) 33 converted by the signal converter 6 into a rotational speed signal proportional to the square root of the head H is converted by the rotational speed controller 7 into a frequency that is equal to or inversely proportional to the rotational speed signal, and is applied to the rotor 27. It is sent to the coil 29 to generate a rotating magnetic pole proportional to the square root of the head H in the coil 29. Three-phase alternating current is input to the stator 28 from the power system input 39, causing the stator 28 to generate a rotating magnetic field. Rotational force (torque) is exerted on the rotor 27 by the rotating magnetic poles on the rotor side and the rotating magnetic field on the stator side.
occurs, and the rotational speed of the rotor 27 in that case becomes a rotational speed determined by the relative difference between the rotational speed of the stator-side rotating magnetic field and the rotational speed of the rotor-side rotating magnetic poles. Therefore, the rotational speed of the runner 21, which is directly connected to the rotor 27 via the main shaft 30, is also the same as the rotational speed. On the other hand, the signal 33 is the pump water turbine governor 9
It is sent to the signal comparator 58 as the rotational speed target value, and at the same time, it is sent to the comparator 64. The load adjustment pressure distribution valve 6 is activated by the signal 62 output from the comparator 64.
The plunger 1, not shown, operates.

The plunger operation of the load adjustment pressure distribution valve 61 causes the auxiliary servo motor 43 to operate using hydraulic pressure as a medium. The operation position signal 52 of the auxiliary servo motor 43 is fed back to the comparator 64, and when the amount of operation of the auxiliary servo motor 43 becomes equal to the magnitude of the signal 33, the operation is completed and the guide vane 24 The position is such that the opening degree becomes the optimum opening degree for the rotational speed proportional to the square root of the head H after the change. In the case of pump operation, the speed regulation device 44 and the damping device 45 are in an off state. The auxiliary servo motor stroke signal 52 is transmitted to the main servo mechanism provided as a signal amplification mechanism, and the secondary pressure distribution valve 4
6. Operate the plunger (not shown). Due to the plunger operation of the secondary pressure distribution valve 46, the main servo motor 31 operates using hydraulic pressure as a medium. Due to the feedback mechanism, the main servo motor 31 ends its operation when the magnitude becomes equal to the auxiliary servo motor stroke signal 52, and the main servo motor 31 reaches a position that matches the changed auxiliary servo motor position. The main servo motor 31 is connected to the guide vane 24 via a guide vane operating mechanism 35, and the guide vane has an optimum opening degree for a rotational speed proportional to the square root of the head H after the change.

FIG. 5 is a structural explanatory diagram showing an example of the signal converter 6 of FIG. 2. In FIG. 5, the head signal is applied to the first signal conversion element 11 to convert it into a rotation amount, thereby rotating the cam 12, and the cam 12 obtains a linear displacement proportional to the square root of the head signal. , this linear displacement is converted into a second transformer consisting of a differential transformer, etc.
The signal converting element 13 converts the head signal into an electric signal to obtain a rotational speed signal proportional to the square root of the head signal.

As in the embodiment of the present invention described above, if the pump-turbine 10 is operated at a variable speed and the rotational speed N is always selected so that the square of the rotational speed is proportional to the head H within the actual operating head range. , mentioned above (1)
In the formula, Nm and Dm have already been determined, so once the actual machine size D is determined, Hm is uniquely determined. Therefore, the model pump's performance obtained from the model test allows operation at all heads.

Therefore, for example, if it is determined that it is most economical to minimize the equipment dimensions in consideration of the operating conditions of the hydroelectric power generation equipment, vibration etc. It becomes possible to minimize the equipment dimensions by setting the actual machine dimensions to point A, which obtains the considered maximum operational head Hm, as the operating point. In this case, the proportionality constant for obtaining the rotational speed signal proportional to the square root of the operating head H of the actual machine is determined so that the head Hm corresponding to point A in FIG. 6 is obtained.

In addition, if it is judged that improving operational efficiency is the most economical, select point B on the diagram shown in Figure 6 to obtain the highest efficiency and determine the actual machine dimensions.
By operating at variable speed so as to obtain the head Hm corresponding to point B, maximum efficiency operation is possible.

In addition, the suction height of hydraulic rotating machines is generally
This refers to the installation height of the equipment relative to the water level in the lower pond, and by determining the required suction height from cavitation performance, the equipment installation position relative to the water level in the lower pond is determined. If it is judged that it is most economical to minimize the suction height in terms of woodwork costs for the building of the hydraulic rotating machine, then on the diagram shown in Figure 6, point C where the cavitation performance is minimum is determined. It becomes possible to select the most economical equipment by determining the actual machine dimensions.

As explained above, according to the present invention, even if the head changes depending on the water level conditions, the pump can be operated at a single point in terms of pump performance obtained through model tests.
This has the effect of enabling economical design of hydraulic rotating machines.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the performance of a general model pump of a hydraulic rotary machine having guide vanes, and Fig. 2 is a block diagram of a device for explaining an embodiment of the method of operating a hydraulic rotary machine according to the present invention. , FIG. 3 is a diagram for explaining the equipment configuration of the pump-turbine and generator motor in FIG. 2, FIG. 4 is a block diagram for explaining the equipment configuration of the pump-turbine governor in FIG. FIG. 6 is a structural explanatory diagram showing an example of the signal converter shown in FIG. 2, and FIG. 6 is a diagram showing model pump performance showing specific operating points for explaining the effects of the present invention. 6... Signal converter, 7... Rotation speed controller, 8... Generator motor, 9... Pump water turbine governor, 10... Pump water turbine, 24... Guide vane, 29...
Coil, 30...Main shaft, 31...Main servo motor, 3
5... Guide vane operation mechanism, 41... Signal converter, 42
...Primary pressure distribution valve, 43...Auxiliary servo motor, 44...
Speed adjustment rate device, 45...damping device, 46...
Secondary pressure distribution valve, 48, 56 to 58, 64... comparator,
61...Load adjustment pressure distribution valve.

Claims (1)

[Scope of Claims] 1. When operating a variable speed hydraulic rotary machine such as a pump or a pump-turbine, a means for obtaining a rotation speed signal proportional to the square root of the head determined by the water level condition is provided, and the rotation from the means is provided. A method for operating a variable-speed hydraulic rotating machine, characterized by operating the machine at a rotational speed of a number signal. 2. The means for obtaining the rotational speed signal is determined by a model test of a variable speed hydraulic rotating machine at a point that minimizes the equipment dimensions in terms of pump performance, a point that obtains the highest efficiency, a point that minimizes the occurrence of cavitation, or any of the above. 2. The method of operating a variable speed hydraulic rotary machine according to claim 1, wherein the method is configured to obtain a rotational speed signal with a comprehensively optimal point in the vicinity of said point as an operating point.