JPS59141774A - Multi-stage hydraulic machine - Google Patents

Abstract

PURPOSE:To satisfy both of the stabilizing property and the quick response property of a system by a method wherein a low-pressure stage guide vane is not responsive to a small width of variation of the revolving number of the machine but is responsive when the revolving number is varied greatly. CONSTITUTION:When a deviation is existing between a guide vane opening degree commanding signal X2 and a high-pressure stage guide vane opening degree detecting signal X2B2 and an output X2B1 is existing at an adding point 16C, the deviation is integrated in high-pressure stage guide vane amplifying section A to operate the high-pressure stage guide vane into a direction to reduce the deviation. The passive state element 15A of a low-pressure stage guide vane control mechanism 15 does not output a low-pressure stage deviation input X2A2 and secures the sufficient stability of the system as far as the value of a deviation between a signal X2 and a low-pressure stage guide vane opening degree detecting signal X2A3 is between -alpha and +beta, while the element 15A continues to operate the low-pressure stage guide vane into a direction outputting the input X2A2 and nullifying the input X2A2 thereby obtaining and securing the sufficient quick response property.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a multi-stage hydraulic machine.

[Prior art]

Figure 1 shows the structure of a two-stage pump turbine, which is a typical example of a multi-stage hydraulic machine. In the figure, 1 is the main shaft, 2 is the casing,
3 is a high-pressure stage guide vane, 4I″i high-pressure stage runner, 5
1 indicates an intermediate ice chamber, 6 indicates a low pressure stage guide vane, 7 indicates a low pressure stage runner, and 8 indicates a raft pipe.

When operating this two-stage pump turbine, water with a predetermined head from an upper pond (not shown) is guided to the casing 2 through a water pipe, passes through a high-pressure stage guide bar 73, and then passes through a high-pressure stage runner 4. Work guided by. High pressure stage runner 4
The water that has done work further flows down, passes through an intermediate water chamber 5, passes through a low-pressure stage guide vane 6, and is guided to a low-pressure stage runner 7, where it does further work.

Both the high-pressure stage runner 4 and the low-pressure stage runner 7 are directly connected to the main shaft 1, and the total torque of both runners 4 and 7 is transmitted to a generator motor (not shown) that is directly connected to the upper part of the main shaft 1. drive This multi-stage hydraulic machine is speed-governed by a not-shown galvanizer. This governor control signal is simultaneously input to the high pressure stage guide vane 3 and the low pressure stage guide vane 76.

Figure 2 is a block diagram of the speed governor control system of this two-stage pump turbine, and in this figure 9 is the governor control section, l
O is the low pressure stage guide vane control mechanism, 11 is the high pressure stage guide vane control mechanism, 12 is the output characteristic of the two stage pump water turbine, 1
3 indicates the inertial effect of the water turbine and the generator, and 14 indicates the acceleration/deceleration energy derivation point.

When the rotational speed Xl is input to the governor control section 9, a guide vane opening command signal X2 is outputted from there. This guide vane opening degree command signal X2 is simultaneously input to both the low pressure stage guide vane control mechanism 10 and the high pressure stage guide vane control mechanism 11, and the low pressure stage kite vane opening degree X3 and the high pressure stage guide vane opening degree X4 are determined. When the low pressure stage guide vane opening degree X3 and the high pressure stage guide vane opening degree X4 are determined, the output X5 of the multistage water turbine is determined by the output characteristic 12.

If the difference between the water turbine output X5 and one generator load X6 (acceleration/deceleration energy) be modified to the value.

However, even if the same deviation occurs in the difference X7 between the water turbine output X5 and the generator load X6, if the inertia effect 13 of the water turbine and the generator is large, the acceleration/deceleration rate will be low, resulting in slow acceleration or slow deceleration.

At present, a speed governor control system for multi-stage pump turbines that can simultaneously satisfy both stability and coordination has not yet reached the stage of being put into practical use.

[Purpose of the invention]

An object of the present invention is to eliminate such problems and provide a multistage hydraulic machine that can simultaneously satisfy both stability and coordination of a multistage pump turbine adjustment control system.

[Summary of the Invention] The present invention provides a multi-stage hydraulic power plant in which a plurality of stages of runners each have a movable guide vane, and these movable guide vanes are provided with an opening/closing control device that operates almost synchronously in response to an input of an opening/closing fluctuation command. The machine is characterized in that the size of the fixed band of one of the opening/closing control devices is smaller than that of the other opening/closing control devices.

In other words, some of the movable guide vanes in the movable guide vanes are designed not to respond to small opening/closing fluctuation command inputs, and are designed not to respond to small width inputs in this range, and to prevent small width command inputs in this range. , the number of movable guide vanes is substantially limited, and on the other hand, all or more movable guide vanes are configured to respond to commands/inputs with a large variation range exceeding this small variation range. .

The present invention was obtained as a result of studies on stabilizing the speed governing control system of the two-stage pump turbine shown in FIG. Second
In order to stabilize the governor control system with the configuration shown in the figure, it is necessary to lower the loop gain. gain + gain of control mechanism 11 of high-pressure stage guide vane) x (gain of output characteristic 12 of multi-stage water turbine) x (gain of inertial effect 13). Therefore,
In order to improve the stability of the system, it is theoretically possible to lower the gain of any block, but the gain of output characteristic 12 of the multi-stage water turbine is a characteristic unique to this two-stage pump water turbine. cannot be adjusted. The gain of the inertial effect 13 can be reduced by increasing GD2 (where G is the weight and D is the average rotating diameter). On the other hand, in a multi-stage pump turbine, it is necessary from a cost standpoint to select the shared water head of each stage close to the possible limit for a single stage and to minimize the number of stages, and it is desirable to increase the rotation speed as high as possible. If you raise it, you will not be able to attach enough GD2 to the generator side,
Realization is extremely difficult. Furthermore, the low-pressure stage guide vane control mechanism 10 and the high-pressure stage guide vane control mechanism 11 are mechanisms themselves that control the opening degree according to a command, and do not need to be adjusted. As a result, the practical solution is to lower the gain F1 of the governor control section 9.

However, if the gain Fl is lowered, the response of the guide vane opening command X2 to the signal X1, in other words, the response of the actual guide vane openings X3 and X4, will become slower, which will reduce the coordination of the system. become.

That is, in the method of adjusting the gain F, the connectivity and stability of the system are in a contradictory relationship because if one is set, the other is not set, and it is difficult to set up a system that satisfies both at the same time.

Note that the speed governor control system in Figure 2 is intended for speed governor control that keeps the rotation speed constant, but it can also be considered for other types of control that keep the flow rate, water pressure, etc. constant. .

Based on these study results, the present invention is based on the fact that the low-pressure stage guide vanes do not react while the rotational speed changes only slightly to ensure sufficient system stability, and when the rotational speed changes significantly, the low-pressure stage guide vanes do not respond. The stage guide vanes also react in response to ensure sufficient coordination.

[Embodiments of the invention]

FIG. 3 is a block diagram showing a speed control system for a two-stage pump water turbine as an embodiment of the present invention. This speed control system consists of a low pressure stage guide vane control mechanism 15 and a high pressure stage kite vane control mechanism 16. In the low pressure stage guide vane control mechanism 15, 15A is a stationary band element;
5B is a low-pressure stage guide vane hydraulic pressure amplifying part, 15c is a low-pressure stage guide vane opening restoring part, 15D is a summing point,
In the high-pressure guide vane control mechanism 16, 16A indicates a high-pressure guide vane hydraulic amplification section, 16B indicates a high-pressure guide vane restoring section, and 16c indicates an addition point.

In this two-stage pump turbine, the kite vane opening command signal x
2 and high pressure stage guide vane opening detection signal X2 B 2,
If there is a deviation between them, that is, if the output X2n1 of the addition point 16c is generated, the high-pressure stage guide vane hydraulic amplifying section 16A' continues to integrate the deviation U, and increases the high-pressure stage in the direction of reducing this deviation. Operate the guide vane tray. This ever-changing high-pressure stage guide vane opening degree X4 is constantly fed back through the high-pressure stage guide vane rear portion 16B, and the command signal X2 and the low-pressure stage guide vane opening degree X4 are compared at a summing point 16c.

In other words, the addition point 16c of the high pressure stage guide vane hydraulic amplifying section 16^ and the high pressure stage guide vane restoring section 16B1 is 1.
This system forms two first-order delay elements, and faithfully responds to the guide vane opening command signal X2, which has a low energy level, and converts it into an output signal with a high energy level. The energy stored in the form is guided to the high-pressure stage guide vane hydraulic amplification section 16A via hydraulic pressure and is consumed as amplification energy.

The operation of the low-pressure stage guide vane control mechanism 15 is also similar to that of the high-pressure stage guide vane control mechanism, but a stationary band element 15A is added. This stationary band element 15A receives a guide vane opening command signal X2 and a low pressure stage guide vane opening detection signal X.
As long as the deviation of 2A3 is between (-α to 10β), it operates so as not to output the low pressure stage deviation manual power XzA2 to the output side. In other words, if the deviation exceeds this range, a signal corresponding to the excess is output as an output signal.

As long as this low-pressure stage deviation manual power X2A2 exists, the low-pressure stage guide vane hydraulic amplifying section 15n performs an integral operation and continues to operate the low-pressure stage guide vane in the direction of zeroing the pressure 2.

As a result, the low-pressure stage guide vane opening degree X3 and the guide vane opening degree command signal X2 do not completely match.

That is, a maximum error of α or β is allowed.

Therefore, if the values of α and β are appropriately selected, the amount of imbalance between the high-pressure stage guide vane opening X4 and the low-pressure stage guide vane opening X3 can be prevented from becoming too large. Note that the size of the stationary band is selected so that the difference in guide vane opening is about ±1 to 251i.

In the end, if the guide vane opening command signal X2 fluctuates only slightly more than the values of α and β, the low-pressure stage guide vane will not respond. In this state, system stability can be ensured even if the coverage control section transfer function IF11 is selected to be quite large. However, if the guide vane opening command signal X2 fluctuates significantly (i.e., <-β or >10α), the low-pressure stage guide vanes will also immediately participate in the control, and the expected system speed response will not be achieved. can be secured.

FIG. 4 is a block diagram showing a speed control system for a two-stage pump-turbine as another embodiment. The same parts as in FIG. 3 are given the same symbols, and corresponding parts are given the same symbols. It is attached. The difference between this embodiment and the embodiment shown in FIG. 3 is that in the embodiment shown in FIG. In contrast, in this embodiment, the opening/closing control device is provided in series with the opening/closing fluctuation command input of the guide vane, and the size of the fixed band is determined by the opening/closing control of the subsequent stage. The difference is that the device is larger.

In this two-stage pump turbine, regardless of the presence or absence of the stationary band element 158', the high-pressure stage guide vane is first controlled, and the low-pressure stage guide vane responds to the actual opening degree of the high-pressure stage guide vane. It is composed of In this case as well, X3' is not made to respond to slight fluctuations in the guide vane opening command signal X2, whereas the high-pressure stage guide vane responds sensitively to fluctuations in rotational speed. ,
This embodiment is similar in that it does not react as long as the fluctuation in the rotational speed of the low-pressure stage guide vane remains within a predetermined range, but in this embodiment, the high-pressure stage guide vane control mechanism and the low-pressure stage guide vane control mechanism are installed in series. The reliability of safety is high.

In addition, in these embodiments, the case of speed control has been described as an example, but it is also applicable to cases where automatic control of flow rate, pressure, etc. is performed.

〔Effect of the invention〕

The present invention makes it possible to provide a multi-stage hydraulic machine that satisfies both system stability and coordination, and is an industrially effective dog.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a two-stage pump turbine, and Figure 2 is the 2nd diagram in Figure 1.
Flock diagram of speed control system of stage pump turbine, Part 3
4 and 4 are block diagrams of speed control systems of different embodiments of the multi-stage hydraulic machine of the present invention. 9... Control unit of the cover, 15... Low pressure stage guide vane control mechanism, 15A... Fixed band element, 15B...
Low pressure stage kite vane hydraulic amplification section, 15c...Low pressure stage guide vane opening restoring section, 15D...Additional point, 16
. ...High pressure stage Kaidobe 7 system-111J Isokai, 16A・
...High pressure stage guide vane hydraulic amplification part, 16B...High pressure stage guide (1 other person) Kaya 1st (Kaya 2 Hard lθ Kaya 3rd note)

Claims (1)

[Claims] 1. A multi-stage hydraulic machine in which a plurality of stages of runners each have a movable guide vane, and these movable guide vanes are provided with an opening/closing control device that operates almost synchronously by inputting an opening/closing fluctuation command. , a multi-stage hydraulic machine characterized in that the size of the fixed band of one of the opening/closing control devices is smaller than that of the other opening/closing control devices. 2. The multistage hydraulic machine according to claim 1, wherein the opening/closing control device that operates synchronously is provided in parallel to the opening/closing fluctuation command input of the movable guide vane. 3. A patent claim in which the opening/closing control device that operates synchronously is provided in series with respect to the opening/closing fluctuation command input of the movable kite vane, and the size of the stationary band is larger in the opening/closing control device at the subsequent stage. A multi-stage hydraulic machine according to item 1. 4. The multistage hydraulic power plant according to claim 1, 2, or 3, wherein in the opening/closing control device that operates synchronously, the size of the fixed band is smaller in the high pressure stage than in the low pressure stage. machine.