JPS6022210A - Digital controller for hydropower plant - Google Patents

Abstract

PURPOSE:To apply a digital controller to a hydropower plant and to improve the arithmetic processing efficiency by detecting a state change of the numberical input and carrying out selectively a nyumerical operation necessary for control in response to the result of said detection. CONSTITUTION:A state change detecting circuits 51 detects an intake level 14 and an intake gate opening 18 to decide the state among 71-74 for the operation of this time. For the outputs of arithmetic processors 23, 25, etc., the result of the preceding operation is held in case any new operation is not performed. Then a sequence needed for control is processed by an arithmetic processor circuit 29, and the output of this circuit 29 drives a motor 16 for operation of intake gate. The opening 18 is controlled toward a target 26 of opening amount in response to the motor gate opening characteristics 31 so that the flow rate of the water passing through an intake gate 2 is set at an amount corresponding to the output command value 12. Thus the motor output 35 is set equal to the command value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a digital control device for a hydroelectric power plant that performs complex numerical calculations.

[Technical background of the invention and its problems]

Recently, digital control devices that widely use microprocessors have been introduced to replace the relay panels and analog regulators that have been used in power plants up until now. At the initial stage of introduction, the processing content of this digital control device was often a direct replacement of the processing of conventional relay panels;
Even when replacing an analog regulator, it can often be processed using simple orange numerical calculations, and the sequence processing is relatively simple and similar to that of a relay board.

On the other hand, in thermal power and nuclear power generation plans, each plant has a postcombinator, which processes complex numerical operations and performs sequence processing and relatively simple numerical operations, and digital control using a microprocessor. This is often done using equipment. However, there are few hydroelectric power plants where host computers are installed, and when replacing conventional relay panels and analog regulators with digital control devices using microprocessors, these hydroelectric power plants have added the conventional functions. In many cases, new functions and higher control precision than before are required. In order to realize these new functions and control accuracy higher than before, it is often necessary to perform complex numerical calculations within the digital control device. 1 shows a general schematic diagram of a water system and a control system of a hydroelectric power plant as implemented by a control device. In the figure, water upstream of the power plant flows into a reservoir or regulating pond 1 through a water conduit (not shown).
This water is guided through a waterway 3 to an upper water tank 4 near the power plant, and further introduced via a guide vane 5 to a water turbine 6 that drives a generator 7, and is thereby guided through a tailrace 8 to a lower pond or river (not shown). In a hydroelectric power plant, the output of the generator 7 is adjusted by detecting the water level 9 of the water tank 4 with a water level detector 10, and using the water level regulator 11 based on the water level 9 of the water tank 4. How the output adjustment is performed will be explained below.

The output command value 12 from a power supply control center etc. and the water intake water level 14 detected by the water intake water level detector 13 are input to the flow rate adjustment control device 15 to which a conventional digital control device is applied, and these data are used. The flow rate of water required to generate the same output as the output command value 12 is determined by
The opening degree of the water intake port f-)2 required for the water to flow out from the water is calculated using the relational expression. Then, the intake dart opening 18 detected by the r-) opening detector 17 attached to the dart operation motor 16 of the water intake log 2 is input to the flow rate adjustment control device 15, and the intake dart opening 18 is calculated using the relational expression. dirt 2
Compare the opening degree with the actual water intake log opening degree 18, and check the difference according to the deviation. -) The operation command 19 is given to the operation motor 16 to drive the water intake log 2, and the outflow amount 20 of water from the reservoir or regulation pond 1 becomes the flow rate necessary to generate power with the same output as the output command value 12. control.

By the way, in the upper water tank 4, the upper water tank water level 9 changes depending on the difference between the amount 21 of water flowing into the upper water tank 4 and the amount 22 of water flowing out from the upper water tank 4. Therefore, the water level regulator 11 drives the guide vane 5 to adjust the outflow amount 22 of water from the water tank 4 so that the water level 9 of the water tank does not change. Here, in the adjustment by the water level regulator 11, when the water tank water level 9 becomes stable, the amount 21 of water flowing into the water tank 4 and the amount 22 of water flowing out from the water tank 4 become the same. And the reservoir is still the regulating pond 1
The amount of water flowing out from the tank 20 and the amount of water flowing into the water tank 4 21.
Since the outflow amount 22 of water from the water supply volume 4 and the flow rate of water used by the water wheel 6 are equal, 22 = 21 = 22 = the flow rate of water used by the water wheel 6, and the outflow of water from the reservoir or regulating pond 1. By adjusting the flow rate 20, the flow rate of water used by the water turbine 6 can be adjusted, and thereby the output of the generator 7 can be adjusted to be the same as the output command value 12.

In a hydroelectric power plant that performs such flow adjustment control, there are often restrictions on the opening/closing width of the water intake log 2 because problems such as transient response of the water system occur when the water intake log 2 is suddenly opened and closed. Therefore, FIG. 2 shows a block diagram of a control configuration when a conventional digital control device implements flow rate adjustment control when there is a limit to the opening/closing width of the water intake dart 2. In the figure, 23 is a calculation process for calculating the flow rate of water required to generate the same output as the output command value 12, that is, the flow rate target value 24, and 25 is the calculation process for calculating the flow rate target value 24 from the reservoir or regulating pond 1. The required water intake log opening, that is, the gate opening target value 26
27 is f
-) A calculation process for calculating the opening degree 18 and the deviation from the water intake port ff detected by the opening target value 26 and the dart opening degree detector 17. r-) Operation command calculation processing for giving an operation command 19 to the operation motor 16 °, 29
3o is a sequence calculation process necessary for flow rate adjustment control, 3o is a calculation process for alarms and monitors related to flow rate adjustment control, and 31 is a motor f- of the dart operation motor 16.
) Opening characteristic, 32 is water tank water level characteristic, 33 is water level regulator characteristic, 34 is water turbine/generator characteristic, and 35 is generator output. 23 to 3o are located in the flow rate adjustment control device 15 shown in FIG.

The plant outline and control configuration blocks shown in Figures 1 and 2 above adjust the generator output 35 of the hydroelectric power plant. Power generation based on water level 9... Output 35
The generator output 35 can be adjusted by adjusting the outflow amount 2o of water from the water reservoir or regulating pond 1, that is, the flow rate of water passing through the water intake port ff-)2.

Therefore, the operation of the flow rate adjustment control for adjusting the flow rate of water passing through the water intake port 2 will be explained below, and the adjustment of the generator output 35 will also be explained.

In this case, the generator output 35 can be adjusted according to the flow rate of water passing through the water intake log 2 as described above, so the flow rate of water used to generate the same output as the output command value 12 can be adjusted. Calculate and adjust the water intake log 2 to the opening degree necessary to flow this usage flow rate, the generator 7 will output the command value 1.
It will generate the same output as 2. Therefore, first, in the arithmetic processing 23, the generator output 35 and the water usage flow rate/
The flow rate of water required to generate the same output as the output command value 12, that is, the target flow rate value 24 is calculated from the relational expression. Next, in the calculation process 25, this flow rate target value 24
The dart opening target value 26 is determined by the relational expression between and water intake water level 14.
is calculated, and the deviation between this 26 and the actual water intake r-
The opening/closing width of the water intake port 2 is limited, and an operation command 19 is given to the water intake port r-) operation motor 16. and,
Sequence processing necessary for flow rate adjustment control is performed by arithmetic processing 29, and processing for alarms, monitors, etc. is performed by arithmetic processing 3o.

When the operation command 19 is given to the dart operation motor 1.6 by the flow rate adjustment control device 15 as described above, the dart operation motor 16 uses the motor/dart opening characteristic 31 to control the actual water intake. f-) Adjust the water intake port 2 so that the opening degree 18 becomes the target gate opening value 26. As a result, the flow rate of water necessary to generate the same output as the output command value 12 passes through the water intake port f-)2, and flow rate adjustment control is performed. The upper water tank water level 9 changes according to the upper water tank water level characteristic 32 due to the flow rate passing through the water intake port 2, and the water level regulator 11 adjusts the guide vane 5 so that this water level change does not occur. For driving purposes, the flow rate of water used by the water turbine 6 is adjusted. Here, the flow rate of water used by the water turbine 6 is the outflow amount 22 of water from the water tank 4, and the inflow amount 21 of water to the water tank 4 is the outflow amount 20 of water from the reservoir or regulating pond 1.
is the same as The water level 9 of the water tank does not change when the amount of water flowing into the water tank 54 21 and the amount of water flowing out 22 of the water tank 4 become equal. From the above, the water level regulator 11 performs an adjustment to equalize the flow rate of water passing through the water intake orifice 2 and the flow rate of water used by the water turbine 6. Therefore, by using the relational expression between the water usage flow rate of the water turbine 6 of this plant and the generator output 35 in the relational expression between the generator output 35 and the water usage flow rate of the water turbine 6 in the arithmetic processing 23 described above, the water intake log 2 By adjusting the flow rate of water passing through, the generator output 35 can be adjusted to be the same as the output command value 12.

By the way, in the flow rate adjustment control as described above, the output command value 12 is usually constant for several tens of minutes, and the water intake water level 14
is a numerical input that maintains a constant value for several minutes, and the calculation processes 23, 25, etc. are not processes that need to be performed constantly. However, in conventional digital control devices, repeated calculations are performed for all calculations, regardless of whether they are necessary or not. Due to the nature of the processing, numerical calculations require several to several tens of minutes (tt) or longer for special calculations, compared to sequence calculations.

Therefore, the calculation processing time for executing calculation processing 23 and 25 occupies a large proportion of the total calculation processing time for this flow rate adjustment control.

Here, FIG. 3 shows a timing diagram of the arithmetic processing of this flow rate adjustment control. In FIG. 3, the numbers on the left side indicate the time during which the arithmetic processing section in FIG. 2 executes each calculation. In addition, A is a state in which the output command value 12 in FIG. A state in which the intake water level 14 does not change and the intake opening 18 changes,
D is the output command value 12. Water intake water level 14. This shows a state in which none of the three numerical inputs for the water intake rod date opening degree 18 has changed. The shaded area in FIG. 3 indicates calculation time not required for control.

As can be seen from Figure 3, in the conventional digital control device, B
, C, and D, a large amount of time is spent processing calculations that are not necessary for control, so the overall processing time for this control becomes long. In addition, when the entire control process needs to be repeated at a fast cycle, this unnecessary calculation limits the calculation time that can be used for other processes, which limits the functions that can be processed in that processing time, that is, the amount of calculation. Sometimes it is done. Moreover, the output command value is 12. Intake water level 1
4. If the water intake dart opening degree of 18 fathoms is an analog quantity, calculations will be performed for minute fluctuations due to drift and noise, but these calculations are also unnecessary for control purposes. As mentioned above, conventional digital control devices perform unnecessary calculations for control, resulting in a lot of wasted calculation time, and this waste of calculation time limits the amount of calculations that can be processed. There were drawbacks.

[Purpose of the invention]

An object of the present invention is to provide a digital control equipment for a hydroelectric power plant that eliminates the waste of calculation time as described above, has high calculation processing efficiency, and can perform appropriate control.

[Summary of the invention]

The present invention focuses on the fact that numerical calculations require several to several tens of times the processing time compared to sequence calculations, and adds a new process to detect changes in the state of numerical input before the conventional calculation processing. By performing the numerical calculations necessary for control based on the state change of the detected numerical input, only the numerical calculations necessary for control among the numerical calculations in the digital control device are performed, thereby eliminating wasted calculation time. In addition to eliminating the calculation time and making effective use of the calculation time, this also reduces the restriction on the amount of calculation due to the calculation time, and also prevents unnecessary calculations using minute and small fluctuations in numerical input. It is characterized by this.

[Embodiments of the invention]

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 4 shows a flow rate adjustment control device 15 according to an embodiment of the present invention.
Fig. 2 shows a control block diagram of the system.

Similarly, the water system and control system of a hydroelectric power plant to which this flow rate adjustment control device 15 is applied are the same as in the conventional case, as shown in FIG.

In Figure 4, 12~14.16~19°23~tei5
is the same as shown in FIG. The arithmetic processing newly added to this control configuration block diagram is the state change detection processing 51, so this will be explained.

This state change detection process 51 is performed when the output command value is 12 degrees and the water intake water level is 14 degrees. A state change detection process for the three numerical inputs of the water intake log opening degree 18 is performed.

FIG. 5 shows a block diagram of the processing contents of this state change detection processing 51. In the figure, the method for detecting a change in the state of the output command value 12 is as follows. First, output command value 12
The comparator 57 compares the output command value 56 used for the previous calculation stored in the storage memory 55 and the current output command value 12, and if the difference is greater than or equal to a predetermined set value 58, the output is output. Detects that the state of command value 12 has changed.

Then, when the state change signal 59 of the output command value 12 indicating that a state change has occurred is turned ON, and the current output command value 12 is selected as the output command value 52 to be used for this calculation, it will also be used for the next calculation. This current output command value 12 is stored in the storage memory 55 for this purpose. In addition, the output command value 12
When the state change signal is OFF, the output command value 56 used in the previous calculation is held. The intake water level is 14. Water intake f-
) The same state change detection processing as for the output command value 12 is performed for the opening degree 18 as well. However, a memory 60 for storing the water intake water level 14 corresponds to a memory for storing the output command value 12.
．． The storage memory 65 for the intake dart opening 18 is blank, and the output command value 56 used for the previous calculation is replaced by the intake water level 61° intake f-) opening 62 for the previous calculation. In addition to the comparator 57 for the command value 12, each comparator 62.
67, and instead of the preset value 58 predetermined for detecting the state change of the output command value 12, there is a predetermined set value 63.68 for detecting each state change.
), the state change signal 59 of the output command value 12 and the state change signal 64 of the water intake water level 14, respectively. Water intake r-)
The point where the state change signal 69 of the opening degree 18 is output and the output light of the numerical input is the water intake water level 53 used for calculation. The only difference is that the water intake dart opening degree is 54.

As described above, the state changes of the three numerical inputs are detected, and the state change signals 59, 64, and 69 are input to the calculation selection process 70, and one of the numerical calculations in the flow rate adjustment control device 15 to which the present invention is applied. , determine which numerical operations need to be performed. 71 is a case where all calculations are performed because the output command value 12 has changed. In case 72, the output command value 12 does not change and the intake water level 14 changes, so the calculation process 23 for calculating the flow rate target value 24 from the output command value 52 used in the calculation is not necessary, but the flow rate target value 24 and the flow rate target value 24 are used in the calculation. The opening degree target 26 is calculated from the water intake water level 53, that is, the updated water intake water level 14 of this time.The calculation processing from the calculation processing 25 to the subsequent calculation processing is necessary. 73 is the output command value 12. This is a case where the water intake water level 14 does not change and the water intake ff-) opening degree 18 changes, so calculation processing 23.degree. 25 is not necessary, and calculation processing 27 and subsequent steps are necessary. 74 has no change in the three numerical values 12°14.18, and the calculation process 23,
This shows a case where 25°27 is not necessary. These 71°, 72, 73, and 74 are in the same state as A, B, C, and D in FIG. 3(2), respectively.

In the above configuration, output adjustment of the present hydroelectric power plant will be explained with reference to FIGS. 1 and 4.

First, the state change detection process 51 determines the output command value 12, the water intake water level 14. Each state change of the water intake dart opening degree 18 is detected, and based on this, the current calculation is 71.72.73.7
4. Decide in which state the process will be carried out. In the case of 71, all the calculations are performed and the calculation processing time similar to that of a conventional digital control device is required. In the case of 72, the calculation process 23 is omitted, and in the case of 73, the calculation process 23.25 is
In 74, since the calculation processes 23, 25, and 27 are omitted, the calculation processing time is shorter than that of a conventional digital control device. Here, the output of each calculation process 23°25.27 is designed to hold the previous calculation result if no new calculation is performed, so the output of calculation process 27 is
The conventional process of adding a limit to the opening/closing width of the intake log 2 to 8 and outputting the operation command 19 to the intake dart operation motor 16 has no problem even if the calculation processes 23, 25, and 27 are omitted. Processing of sequences necessary for control is performed by calculation processing 29, and processing of alarms, monitors, etc. is performed by calculation processing 30.
Let's do it as follows. Operation command 1 output in this way
9 drives the motor 16 for operating the water intake rodato. From then on, the conventional flow rate adjustment control device 15 drives the motor ? -) Adjust the water intake f-) opening 18 to the gate opening target value 26 according to the opening characteristic 31, and thereby the flow rate of water passing through the water intake f-) 2 reaches the output command value 12. Similarly to the corresponding flow rate target value 24, the water level regulator 11 is set to the upper water tank water level characteristic 3.
2. Drive the guide vane 5 via the water level regulator characteristic 33. Thereby, the generator output 35 generated according to the water turbine/generator characteristics 34 is adjusted to be the same as the output command value 12.

As described above, by adjusting the flow rate passing through the water intake dart 2, the generator output can be increased to 35
It is possible to realize control that adjusts so that the output command value becomes the same as the output command value 12. Here, flow rate adjustment control device 1 to which the present invention is applied
Let's take a look at the calculation processing time in 5. FIG. 6 is a timing diagram of the arithmetic processing and corresponds to FIG. 3 described above. Similarly to FIG. 3, in FIG. 6, the numbers on the left side indicate the calculation processing in FIG. 4), and the general portion is the execution time of each calculation. Further, 71.72.73.degree. 74 indicates the state of change of each of the numerical inputs described above, similar to A, B, C, and D in FIG.

In Figure 6 of cylinder 6, a state change detection process 51 that was not present in Figure 3 has been added, but according to the present invention, it can be seen in Figure 3.
The waste (or part) of the arithmetic processing time in the 9D state is removed, and the processing time is shortened accordingly.

Normally, the output command value 12 remains constant for several tens of minutes, and the water intake water level also maintains a constant value for several minutes, but during this time B in Fig. 3,
Since this corresponds to states C and D, the flow rate adjustment control device to which the present invention is applied can process calculations necessary for control in a shorter time than the conventional device. Further, when the calculation is performed repeatedly at regular intervals, the calculation time can be increased. Moreover, in the state change detection process 51, unnecessary calculations such as using numerical values of minute fluctuations in numerical input due to noise etc. can be prevented, and calculations appropriate for control can be performed.

In the above embodiment, the need to perform arithmetic processing was detected based on the amount of change in each numerical input, but if the numerical calculation using that numerical input is related to the rate of change of that numerical input, the arithmetic processing is performed. The rate of change of the numerical input may be used to detect the necessary case.

Furthermore, if various numerical calculations are included, the necessity of the calculation processing may be detected by combining the rate of change of the bush value input. [Effects of the Invention] As described above, the present invention According to the method, changes in the state of numerical inputs are detected, and numerical calculations necessary for control are selected and executed based on the detection results, thereby reducing the calculation processing time that was previously spent on calculations that are not necessary for control. It eliminates waste, shortens calculation processing time and increases processing efficiency, making it suitable for use in hydropower plants where complex numerical calculations are required due to the lack of a host computer, etc. A digital control device is obtained.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the water system and control system of a typical hydroelectric power plant, Figure 2 is a block diagram of a conventional flow rate adjustment control device, Figure 3 is a calculation processing timing diagram of conventional flow rate adjustment control, and Figure 4 The figure is a block diagram of a flow rate adjustment control device according to an embodiment of the present invention, Figure 5 is a block diagram of the processing contents of the state change detection process in Figure 4, and Figure 6 is the calculation process of flow rate adjustment control in Figure 4. FIG. 12.52.56...Output command value, 23.25. 27... Arithmetic processing, 51... State change detection processing, 5
3゜61...water intake water level, 54.66...water intake f
-) Opening degree, 55.60.65... Memory for storage, 57
゜62.67... Comparator, 58.63.68... Setting value, 59.64169... Status change signal, 70...
- Calculation selection process, 71... When performing all calculations,
When performing calculations after 72...25, 73...2
When performing calculations after 7, 74...23.25.2
When operation 7 is not necessary.

Claims (1)

[Claims] (1) In a digital control device for a hydroelectric power plant that periodically performs numerical calculations in order to realize required control, a storage means for storing a plurality of numerical inputs used in the previous numerical calculation, and a storage means for storing the plurality of numerical inputs used in the previous calculation of the numerical calculations; Compare each of the current values of the plurality of numerical inputs corresponding to the numerical value, and change the state of each of the plurality of numerical inputs on the condition that the amount of change in each of the plurality of numerical inputs is greater than or equal to a preset value. What is claimed is: 1. A digital control device for a hydroelectric power plant, comprising: detecting means, and performing only numerical calculations related to numerical inputs whose state changes have been detected. (2. A digital control device for a hydroelectric power plant according to claim 1, characterized in that the rate of change of each numerical input is used as means for detecting a change in the state of each of the plurality of numerical inputs ( 3) In claim 1, the means for detecting a change in state of each of the plurality of numerical inputs is a combination of the amount and rate of change of the numerical inputs by taking into account the characteristics and calculation contents of each numerical input. A digital control device for a hydroelectric power plant characterized by its use in