JPS6271497A - Controller for variable-speed hydraulic turbine generator - Google Patents

Abstract

PURPOSE:To improve the stability of an AC system by directly controlling a generating output in response to a generating output command from the outside. CONSTITUTION:A rotational-speed command arithmetic section 15 outputs an optimum revolution-number command Na in response to an external generating output command P0 and a water-level signal H. A rotational speed controller 16 compares the optimum revolution-number command Na with a rotational speed signal N, and outputs a guide-valve opening command Ya to a guide valve 11 for a hydraulic turbine 2. A frequency controller 3 controls the phase of AC exciting current fed to a secondary winding 1b for a winding type induction motor 1 in response to the external generating output command P0, a slip-phase signal SP and a generating output P. Accordingly, the generating output can be followed up smoothly to the generating output command, thus improving the stability of an AC system.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a variable speed water turbine power generation system using an induction machine and a secondary excitation control device connected to the secondary side of the induction machine, and particularly relates to a variable speed water turbine power generation system using an induction machine and a secondary excitation control device connected to the secondary side of the induction machine. The present invention relates to a control device for a variable speed water turbine generator suitable for realizing operation and frequency control.

[Background of the invention]

One of the main purposes of controlling the speed of rotating electric machines is to control the rotational speed according to the load of a turbomachine such as a pump water turbine, thereby realizing the highest efficiency operation of the turbomachine. Methods for variable speed operation of the water turbine of a water turbine generator can be roughly divided into two types.

The first method is to provide a frequency converter between the AC system and the generator. Japanese Patent Laid-Open No. 48-21045 makes it possible to supply power to the AC system even when the generator is operated at any rotation speed, and the rotation speed is adjusted by opening and closing the guide valve of the water turbine to operate the water turbine at its highest efficiency point. A method to achieve this has been proposed.

The second method is to connect the primary side of the wound induction machine to the AC system and provide a frequency converter between the secondary side and the AC system.

This method connects the primary side of a wire-wound induction machine to an AC system.
It has long been known as a typical application example of the 8 methods of installing a frequency converter between the next side and the AC system and controlling the rotation speed according to the generator output, and is based on the Electrical Engineering Handbook (published by the Institute of Electrical Engineers of Japan, 1966 edition). ) etc. are also described. Examples of control devices for this type of variable speed water turbine generator include those disclosed in JP-A No. 52-46428, the specification and drawings of Japanese Patent Application No. 57-182920, and JP-A No. 55-56499. is proposed.

A problem common to the above two types of variable speed water turbine generators is how to control the water turbine output and the generator output to control the rotation speed. Specifically, how is the speed deviation signal (Na-N) obtained by comparing the optimum rotational speed command value Na calculated from a signal including the external power generation output command signal PO indicating the water turbine operating conditions with the rotational speed detection value N? The challenge is how to use it to control the output of water turbines and generators. This is because when adjusting the rotational speed by mechanically connecting a water turbine and a generator, the fluid kinetic energy of the waterway system is smaller than the rotational kinetic energy of the mechanical system, and the loss of one generator can be almost ignored. This is because most of the difference between the water turbine output and the generator output is an increase or decrease in rotational kinetic energy.

Here, the external power generation output command Po is an internal power generation output command calculated from measurement signals such as voltage, current, frequency, phase, and rotation speed of equipment that constitutes a variable speed power generation device such as a water turbine or generator 1 frequency conversion device. means a power generation output command other than the power generation output command. Specifically, it means a power generation output command from outside the power generation device, such as a central power dispatch center.

Japanese Unexamined Patent Publication No. 1983-1983, which was cited as a proposal for a method of connecting the primary side of a wound type induction machine to an AC system and installing a frequency converter between the secondary side and the AC system in a control device for a variable speed water turbine generator.
The device of Publication No. 56499 proposes a configuration in which three types of measurement signals, namely the speed 11 of the driving medium (water flow rate in the case of a water turbine), rotation speed, and generator stator output, are used for generator output control and water turbine output control. ing.

However, there are no concrete proposals regarding how to control the generator output and water turbine output to control the rotation speed, nor how to make the generator output respond to the external power generation output command Po. There are no concrete proposals.

Japanese Patent Application Laid-open No. 52-46428 and Japanese Patent Application No. 57/1987 cited as proposals for a control device for this type of variable speed water turbine generator.
The specification and the drawings of No. 182920 propose a control method for controlling the generator output using a rotational speed deviation signal.

An example of the configuration of a control device for these variable speed turbine generators is shown in the first example.
6, in FIG. 16, 1 is an induction machine that is rotationally driven by a water wheel 2 directly connected to its rotor, and the secondary winding 1b of the induction machine 1 is equipped with a frequency converter for secondary excitation. Control equipment! i! 3 supplies an AC excitation current adjusted to a predetermined phase according to the rotational speed of the induction machine 1, and the primary winding 1a of the induction machine 1 outputs AC power with a frequency equal to that of the AC system 4. Variable speed operation is performed. 5 is a water turbine characteristic function generator which inputs the external power generation output command Po and water level detection signal H given from the outside, and generates the optimal rotation speed command Na and the optimal guide valve opening/degree command Ya for operation at maximum efficiency. do. A slip phase detector 7 detects a slip phase Sp that is equal to the difference between the voltage phase of the AC system 4 and the secondary rotation phase of the induction machine expressed in electrical angle. The rotor of the slip phase detector 7 is provided with a three-phase winding connected in parallel with the primary winding 1a of the induction machine 1, and the stator side of the slip phase detector 7 has an electrical angle of π/2. One Hall converter is provided at different positions, and a signal in which the voltage phase of the AC system 4 as seen from the secondary side of the induction machine 1 matches is detected by the Hall converter, and the slip phase S is detected by the Hall converter.
converted to p.

Reference numeral 8 denotes an induction motor output command device which compares the optimum rotation speed command Na from the water turbine characteristic function generator 5 with the rotation speed detection signal N from the rotation speed detector 6 to generate an induction motor output command PG. This induction machine output command PG and the slip phase signal sp of the slip phase detector 7 are input to the secondary excitation control device 3, and the output detection signal P of the induction machine 1 detected by the active power detector 9 is the induction machine output. The AC excitation current supplied to the secondary winding 1b of the induction machine 1 is controlled so as to be equal to the command PG. Specifically, the control method proposed in Japanese Patent Publication No. 57-60645 can be applied. 10 is a guide valve driving device which adjusts the opening degree of the guide valve 11 according to the optimum guide valve opening command Ya from the water turbine characteristic function generator 5, and adjusts the opening degree of the guide valve 11 to generate the water turbine output PT.
control.

In such a control device, in order to increase the power generation output P in a stepwise manner, the external power generation output command Po is set to the first level.
When changed as shown in Fig. 7 (a), the optimum rotational speed command Na increases as the power generation output command Po increases in a stepwise manner.
The optimum guide valve opening command Ya also increases in a stepwise manner as shown in FIGS. As shown in FIG. 17(e), as the opening degree of the guide valve 11 changes, the water turbine output PT also changes as shown in FIG. The value corresponds to the command Po. On the other hand, in order to increase the rotational speed N of the induction machine 1 as shown in FIG. 17(f) to match the optimum rotational speed command Na, the kinetic energy of the rotation system of the power generation device is required to correspond to the increase. need to be increased. The only way to compensate for this increase in kinetic energy is to increase the water turbine output PT or reduce the power generation output P.However, as mentioned above, the water turbine output is determined by the opening Y of the guide valve 11, which changes in accordance with the optimum guide valve opening command Ya. Since PT is fixed, the water turbine output FT will not increase immediately. For this reason, the increase in kinetic energy is supplied to the rotating system by reducing the power generation output P, and as shown in Fig. 17 (g), the power generation output P that should be increased temporarily decreases. Problems arise in the operation of the power system. In order to prevent this transient decrease in the power generation output P, the optimum rotation speed command Na from the water turbine characteristic function generator 5 is set within the induction motor output command device 8 to a device that suppresses sudden changes in signals such as primary weekly nine factors. A conceivable method is to compare the output of this device with the rotational speed detection signal N from the rotational speed detector 6 to generate the induction machine output command PG.

With this method, a part of the increase in the water turbine output PT is supplied to the increase in rotational kinetic energy, and the rest is supplied to the increase in the output P of the induction motor 1.
It can be divided into the increase in However, even with this method, the output P of the induction machine 1 increases faster than the increase in the turbine output PT.
It is not possible to increase the current by 2,000 yen, and the response speed of the power generator is suppressed by the response of the guide valve drive device 10. This problem also occurs when attempting to lower the external power generation output command Po in a stepwise manner. These problems fundamentally arise because the rotational speed N is controlled by adjusting only the output of the induction machine 1.

The problems of the conventional technology regarding output control, rotation speed control, and rotation speed control of a variable speed water turbine power generation device have been described above. Next, problems when controlling the frequency of an AC system using a variable speed water turbine generator will be explained.

A characteristic feature of power generation equipment that performs variable operation by installing a secondary excitation control device equipped with a frequency converter between the secondary side of the induction machine and the AC system is that the rotation speed and the frequency of the AC system do not match. Can be mentioned. In response to this point, Japanese Patent Application Laid-Open No. 58-19904 describes a method for controlling the frequency of an AC system to a predetermined value.
Device No. 1 has been proposed. This proposal suggests that in order to control the frequency, it is necessary to control the power generation output to the AC system, but on the other hand, in order to maintain the rotational speed at an optimal value, the water turbine must supply an output that matches the change in the power generation output. This is a study that focuses on the unknown points. A configuration example of this proposal is shown in FIG.

Items in FIG. 18 with the same numbers as those in FIG. 16 above indicate the same items. Here, only the parts in FIG. 18 that are different from FIG. 16 will be explained.

13 is a frequency detector that detects the frequency f of the AC system 4, and 14 is a frequency control device that compares the frequency detection signal j and the frequency setting value and calculates the power generation output command correction signal APo. Consider a case where this power generation output command correction signal APo increases stepwise and the input to the water turbine characteristic function generator 5 increases stepwise.

In this case, the response of the output P of the induction machine 1 is as shown in FIG.
The change is exactly the same as in g).Therefore, the original purpose of frequency control is to use the output P of the induction machine 1 to generate electricity.

There is a problem in that the frequency deviation increases transiently because no response is made in response to changes in the output command correction signal IPo.

[Purpose of the invention]

The purpose of the present invention is to solve the problems of the prior art described above,
The purpose is to increase the stability of an AC system by making the power generation output follow the power generation output command smoothly without reducing the power generation efficiency.

[Summary of the invention]

In a variable speed water turbine power generation system, when converting the potential energy of water into electrical energy using a water wheel and a generator, the water turbine output and generator output (to be exact, it is the generator input, but in general the generator loss can be ignored) ) increases or decreases the kinetic energy of the rotating part, resulting in a change in rotational speed.

The present invention focuses on the fact that in the case of a variable speed water turbine generator, the kinetic energy of this rotating part is a value that cannot be ignored compared to the electrical energy, and basically the output response of the water turbine to the generator output response is This delay is transiently absorbed by the kinetic energy of the rotating part, and the generator output is directly controlled according to the power generation output command, and signals indicating the turbine operating conditions, including the power generation output command signal from the outside, are The present invention is characterized by being provided with a rotation speed control device that inputs an optimum rotation speed command signal and compares the rotation speed detection signal from the rotation speed detector to control the guide valve opening control signal to the guide valve drive device. .

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of claim 1,
Components having the same numbers as those in FIG. 16 used to explain the conventional example indicate the same products. Here, the parts different from those in FIG. 16 will be explained in detail, and the explanation of the common parts will be omitted. 15 is a rotational speed command calculator that receives an external power generation output command Po.
An optimum rotational speed command Na is generated in response to a water level signal H from the outside. In the case of a power generation device with little water level fluctuation, the optimum rotation speed command Na may be generated from only the external power generation output command Pa without inputting the water level signal H. 16 is a rotation speed control device that generates the optimum rotation speed command Na. The rotation speed signal N detected by the rotation speed detector 6 is compared to generate the guide valve opening command Ya.

FIG. 2 shows one embodiment of the rotational speed control device 1116.

17 is a comparator which outputs the rotational speed deviation ΔN.

This rotational speed deviation JN is inputted to a comparison element (Kl) 18 and an integral element (K2/5) 19, and these outputs are sent to the guide valve drive device 1 by an adder 20 as a guide valve opening command Ya.
It is input to 0.

On the other hand, the external power generation output command PO is input to the rotational speed command calculator 15 and is also input to the secondary excitation control device 3 as a power generation output command.

In the control device configured in this manner, if the power generation output command PO is increased in steps as shown in FIG. The power generation output P increases following the change in the power generation output command PO as shown in FIG. 3(g). On the other hand, since the optimum rotation speed command Na increases in a stepwise manner as shown in FIG. 3(e), the guide valve opening degree command Ya increases due to the change in the output of the proportional element 18, as shown in FIG. 3(b). It changes in steps like this. However, the response of the opening degree Y of the guide valve 11 is slower than the response speed of the induction motor output P to the above-mentioned power generation output command PO. Therefore, the water turbine output PT is smaller than the induction motor output P, and the rotation speed N is lower than the power generation output command PO. After the sudden change in the output command Pa, the speed is temporarily decelerated, and then at time t1, the power generation output P and the water turbine output PT become equal, and the rotational speed N becomes minimum. Note that since the speed deviation AN is positive at time t1, the guide valve opening command Ya continues to increase due to the integral element 19.

Therefore, the guide valve opening degree Y continues to increase, and at one point in time t2, the rotational speed N becomes equal to the optimum rotational speed command Na, and the guide valve opening degree Ya becomes maximum. After that, guide valve opening degree Y and rotation speed N
Since there is no damped vibration, the rotational speed N is the optimum rotational speed command Na
Set to . At time t3 and t5 in FIG. 3, water turbine output PT and power generation output P are equal, and at time t4, rotational speed N and maximum rotational speed command Na are equal.

From the above, guide valve 1 responds to changes in external power generation output command Po.
The power generation output P follows faster than the response of 1, and the rotational speed N
It is possible to settle the rotation speed Na to the optimum rotation speed Na. This first uses rotational kinetic energy to make the power generation output P follow the change in the external power generation output command PO, and while keeping the output P of the induction machine 1 at the external power generation output command PO, the optimum rotation speed command Na is maintained. The rotational and kinetic energy necessary to adjust the rotational speed N is realized by controlling and supplying the guide valve 11.

FIG. 4 is a diagram showing another embodiment. Here, the parts that are different from those in FIG. 1 will be explained in detail, and the explanation of the common parts will be omitted. Reference numeral 5 denotes a water turbine characteristic function generator, which generates an optimum guide valve opening degree command Ya and an optimum rotational speed command Na from the external power generation output command Po and the water level signal H. If the water level fluctuation is small, the water level signal H can be omitted.The zero rotation speed control device 16 has the same configuration as that shown in FIG. 2 and outputs the guide valve opening correction signal ΔY.

The optimum guide valve opening command Ya from the water turbine characteristic function generator 5 is converted into the guide valve opening correction signal l! by an adder 21. IY
The configuration is such that the sum is added and input to the guide valve drive device 10.

In the control device of this embodiment configured as described above, at time point 10, for example, in order to increase the power generation output P in a stepwise manner, the power generation output command PO is increased in a stepwise manner as shown in FIG. 5(a). and the power generation output P of the induction machine 1 is the fifth
As shown in Figure (g), it increases following the change in the power generation output command Po. On the other hand, the response of the opening Y of the guide valve 11 to the optimum guide valve opening command Ya is slower than the response of the power generation output P to the power generation output command PO. Therefore, the water turbine output PT is smaller than the power generation output P. The rotational speed N is temporarily decelerated after the sudden change in the power generation output command Po, and thereafter, at time t1, the power generation output P and the water turbine output PT become equal, and the rotational speed N becomes minimum. Note that at this time t1, the speed deviation ΔN is positive, so the guide valve opening degree correction signal ΔY is positive, and the guide valve opening degree Y becomes even larger than the optimum guide valve opening degree command Ya. Therefore, the water turbine output PT becomes larger than the power generation output P, and the rotational speed N starts to increase as shown in FIG. 5(f). As the rotational speed N increases, the deviation from the optimum rotational speed command Na becomes smaller.
As the guide valve opening/degree correction signal AY decreases, the water turbine output PT decreases, and the acceleration of the rotation speed N decreases.

Using the embodiment shown in Fig. 4, the speed deviation Δ in steady state is
N becomes zero due to the integral element 19. On the other hand, the optimum guide valve opening command Ya and the guide valve opening Y from the water turbine characteristic function generator 5
The deviation corresponds to the error between the water turbine characteristics stored in the water turbine characteristic function generator 5 and the actual characteristics of the water turbine 2, and can be reduced to almost zero by increasing the accuracy of the water turbine characteristic function. . Therefore, it is sufficient for the integral element 19 to generate only the guide valve opening deviation (Ya-Y) during steady state. This is in contrast to the embodiment shown in FIG. 1, in which the integral element 19 must generate all of the guide valve opening command Ya during steady state.

As a result, in the embodiment shown in FIG. 1, in order to speed up the response of the guide valve 11, the gain of the integral element 19 has to be increased by more than a certain degree, but as a compensation, the water turbine as shown in FIGS. 3(e) and 3(f) is used. The output PT and rotational speed N have a somewhat oscillatory response. On the other hand, in the embodiment shown in FIG. 4, the response speed can be increased even if the gain of the proportional element 18 with the braking result is increased by 1 and the gain of the integral element 19 is relatively decreased by 2. Furthermore, Figure 5 (
As shown in e) and (f), the water turbine output PT and rotational speed N can be stabilized without braking.

FIG. 6 is a diagram showing still another embodiment. Since this embodiment is a modification of the embodiment shown in FIG. 4, the parts different from those in FIG. 4 will be described in detail.

Explanation of common parts will be omitted. A comparator 22 outputs a deviation ΔN between the optimum rotational speed command Na and the detected rotational speed value N.

This rotational speed deviation AN is the power generation output correction command bag fi! 23
input to this power generation output correction command device i! The output signal ΔP1 of 23 and the power generation output command signal Pa from the outside are sent to the adder 2.
Secondary excitation control device through 4! 3 as a power generation output command signal.

The functions of the power generation output modification command device 23 will be explained.

When the absolute value of rotational speed deviation ΔN is smaller than N1.

The power generation output correction command signal ΔP1 remains zero, and when it exceeds N1, the absolute value of the power generation output correction command signal ΔP1 also increases in proportion to the increase in the absolute value of the rotational speed deviation ΔN. The absolute value of this power generation output correction command signal JPI is outputted so as not to exceed Pl.

In the control device configured in this manner, for example, in order to increase the power generation output P in a ramp-like manner to a value near the maximum output of the water turbine, the power generation output command PO is set as 711(a).
The response when increasing in a ramp shape as shown in Figure 2 will be explained. First, for comparison, the response when the power generation output command is ramped up under the same conditions in the example shown in Fig. 4 is shown in Fig. 8.
As shown in the figure.

When increasing the power generation output command Po in a ramp-like manner from time to to t3 as shown in FIG. 8(a), up to time tl, the
As shown in Figure (c), the optimum rotational speed command Na remains at the minimum rotational speed determined by the rated voltage of the secondary excitation control device, etc.
Until time t1, the optimum guide valve opening degree command Ya and the guide valve opening degree Y are almost equal as shown in 8th m(b).6 From time point t1, the optimum rotational speed command Na increases as the power generation output command pO increases, Due to the deviation ΔN from the rotational speed N, the guide valve opening degree Y becomes larger than the optimum guide valve opening degree command Ya from the water turbine characteristic function generator 5, and a part of the water turbine output starts to be supplied as an increase in rotational kinetic energy. At time t2, the guide valve opening degree Y reaches the maximum value, and the water turbine output PT remains almost constant as shown in Fig. 8(d).In order to bring the 0 rotation speed N closer to the optimum rotation speed command Na, the water turbine output PT must be adjusted. It is necessary to increase the rotary kinetic energy to a value greater than the power generation output P. However, as shown in FIGS. 8(d) and 8(e), from time t3 onwards, the increase in rotational kinetic energy becomes smaller as the final value of the power generation output command Po becomes larger, and the acceleration of the rotational speed N also becomes smaller. As a result, the rotational speed deviation AN becomes small and the guide valve opening Y starts to settle to the optimum guide valve opening command Ya.
4, and the water turbine 2 cannot be operated at its highest efficiency until the rotational speed N settles to the optimum rotational speed command Na. In some cases, the efficiency decrease due to this cannot be ignored. On the other hand, the response shown in FIG. 7 in the embodiment shown in FIG. 6 is exactly the same as the response shown in FIG. 8 described above up to time t1. As shown in FIG. 7(c), the rotational speed deviation ΔN starts to increase from the time t1 when the optimum rotational speed command Na starts to rise, and the rotational speed deviation ΔN reaches N1 set by the power generation output correction command device 23 at the time t2. After time t2, the power generation output correction command device 23 generates a power generation output correction command ΔP1 in a direction that offsets the power generation output command PO input from the outside to the secondary excitation control device 3. This results in the 7th [! r(
As shown in e), the power generation output P becomes lower than the power generation output command Pa, and the acceleration of the rotational speed N increases as the difference between the water turbine output PT and the power generation output P increases. At time t3, the guide valve opening Y reaches its maximum value, and at time t4, the power generation output command PO reaches its maximum value.At time t5, the rotational speed deviation ΔN becomes N1 again.
5, and the power generation output command command signal ΔP1 becomes zero.
At time t6, as the rotational speed N approaches the optimum rotational speed command Na, the guide valve opening degree Y begins to decrease and reaches the optimum guide valve opening degree Ya.
Set to . As a result, by suppressing the power generation output P from time t2 to time t5, acceleration to the optimum rotational speed command value Na can be accelerated.
This method is effective when changing the power significantly, and is particularly suitable for controlling a variable speed water turbine power generator where the moment of inertia of the rotating part is relatively large relative to the rated power output.

FIG. 9 is a diagram showing still another embodiment. This embodiment is a modification of the embodiment shown in FIG.

Here, the parts different from those in FIG. 4 will be explained in detail, and the explanation of the common parts will be omitted. The rotational speed N detected by the rotational speed detector 6 is input to the power generation output correction command device 25, and this power generation output command command deviceff! The output signal ΔP2 of 25 and the power generation output command signal PO from the outside are inputted to the secondary excitation control device 3 as a power generation output command signal through an adder 26. Power generation output correction command device 25 shown in FIG.
6 When the rotation speed N is between the set value N2 and N3, the power generation output correction command signal ΔP2 remains zero, and when the 1 rotation speed N becomes lower than the set value N2, the power generation output correction command signal ΔP2 It decreases in proportion to the decrease in rotational speed N.

On the other hand, when the rotational speed N becomes higher than the set value N3, the power generation output correction command signal ΔP2 increases in proportion to the increase in the rotational speed N.

The absolute value of this power generation output correction command signal ΔP2 is outputted so as not to exceed P2. Here, the set values N2 and N3 correspond to the rotation speed range determined by the voltage rating and frequency output range of the frequency converter constituting the secondary excitation control device 3, the strength of the mechanical parts of the induction machine 1 and the water turbine 2, etc.

In the control device configured in this way, the power generation output command PO is set to 10 in order to increase the power generation output P in a stepwise manner when the rotational speed N is around the set value N2 at the current time to.
As shown in Figure (a), the response when increasing stepwise is explained. When the power generation output command PO increases at time 0 10, the rotation speed N changes as in the above-mentioned Figure 5. What is the change in the optimum rotation speed command Na? On the contrary, it once decreases as shown in FIG. 10(f). When the rotational speed N becomes lower than the set value N2, the power generation output command input to the secondary excitation control device 3 by the power generation output correction command ΔP2 becomes smaller than the power generation output command PO from the outside. Therefore, the time t1 at which the water turbine output PT and the power generation output P match is earlier than the time t2 at which the water turbine output FT matches the power generation output command Po. Therefore, by adopting this embodiment, the point in time when the rotational speed N becomes minimum is shown in Fig. 10 (f
), what was at time t2 moves to time t1.

At the same time, it is also possible to significantly reduce overshoot in the opposite direction of transient speed. This embodiment is effective for controlling the rotation speed within the rotation speed setting range of the variable speed water turbine generator. Needless to say, this embodiment can also be implemented in combination with the embodiment shown in FIG.

FIG. 111 shows still another embodiment. Since this embodiment is a modification of the embodiment shown in FIG. 4, parts different from those shown in FIG. 4 described above will be described in detail, and explanations of common parts will be omitted. 13 is a frequency detector that detects the frequency f of the AC system 4, and 27 is a frequency control device that compares the frequency detection signal f of the AC system 4 with the frequency setting value fo and outputs a power generation output correction command signal AP3. This power generation output correction command signal AP3
is applied to the power generation output command Po from the outside by the adder 28 and inputted to the water turbine characteristic function generator 5 and the secondary excitation control device 3. FIG. 12 shows the frequency control device 27.
It is a figure showing one example of this.

A comparator 29 outputs a deviation Af between the frequency setting value fo and the frequency detection signal f. This frequency deviation Af is input to a proportional element 30 and an integral element (K4/S) 31, and the outputs of these are input to a limiter 33 via an adder 32. The limiter 33 is configured to suppress the absolute value of the power generation output correction command signal ΔP3 to below P3.

With this configuration, the power generation output correction command signal ΔP3 calculated from the frequency deviation Δf can be used to adjust both the water turbine guide valve drive device 10 and the secondary excitation control device 3, thereby achieving frequency control and stable rotation speed control. It can be achieved.

FIG. 13 is a diagram showing still another embodiment. Since this embodiment is a modification of the embodiment shown in FIG. 4, parts different from those in FIG. 4 will be described in detail, and explanations of common parts will be omitted. Although there is no concrete proposal yet on how to handle the situation when the power generation output command from the outside is outside the power generation range of the power generation device in a variable speed water turbine power generation device, Fig. 13 is a diagram showing an example of this processing method. . 34 is a power generation output limiting calculator, which controls the output to P5 when the power generation output command signals P and o from the outside exceed the set value P5, and suppresses the output to P4 when it is smaller than the set value P4, and controls the secondary excitation control device. 3 and is input to the water turbine characteristic function generator 5.

FIG. 14 is a diagram showing another embodiment that is a modification of the embodiment shown in FIG. 13. Reference numeral 35 denotes a power generation output limit calculator, which, like the power generation output limit calculator 34 described above, is configured to suppress the power generation output command Po within a range determined by set values P4 and P5. However, in the power generation output limit calculator 35, the set values P4 and P
The 0 power generation limit function generator 36, which has a configuration in which 5 is inputted from the power generation limit function generator 36, receives the water level signal H and generates the power generation output upper limit value P5 and lower limit value P4. These upper and lower limit values P4 and P5 are determined by the hydraulic characteristics of the water turbine 2, the output limit of the induction machine 1, the voltage output limit of the secondary excitation control device 3, the output frequency range, etc. According to this embodiment, water level fluctuation It is possible to prevent overload of a large variable speed water turbine generator.

FIG. 15 is a diagram showing another embodiment that is a modification of the embodiment shown in FIG. 14. Reference numerals 341 and 342 denote power generation output limit calculation units having the same configuration as the power generation output limit calculation unit 34 described above. The power generation output limit calculator 341 includes an adder 28 for frequency control and a water turbine characteristic function generator.

The power generation output limit calculator 342 is installed between the power generation output command input of the biopsy 5 and the power generation output command input of the secondary excitation control device 3. According to this embodiment, overload prevention can be realized even when the output commands to the water turbine and induction machine are modified for frequency control or rotation speed adjustment.

〔Effect of the invention〕

As explained above, according to the present invention, the power generation output is directly controlled from outside according to the power generation output command, so even if the power generation output command suddenly changes, the power generation output can smoothly follow the power generation output command. This has the effect of increasing the stability of the AC system. Furthermore, when there is a large deviation between the 1-rotation speed and the optimum rotation speed, the way the power generation is output is adjusted transiently, which has the effect of operating without reducing power generation efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a control device according to an embodiment of the present invention, FIG. 2 is a block diagram of an embodiment of a rotational speed control device forming a part of FIG. 1, and FIGS. (g) is a waveform diagram of signals in each part of the control device, FIG. 4 is a block diagram of a control device according to another embodiment of the present invention, and FIGS.
(g) is a waveform diagram of signals in each part of the control device,
The figure is a block diagram of a control device according to still another embodiment of the present invention, FIGS. 7(a) to (e) are waveform diagrams of signals in each part of the same control device, and FIGS. 8(a) to (e) is a waveform diagram of signals in each part of the control device in FIG. 4 for comparison and contrast with FIG. 7, FIG. 9 is a block diagram of a control device according to still another embodiment of the present invention, and FIG. 10(a) -(g) are waveform diagrams of signals in each part of the control device, FIG. 11 is a block diagram of a control device according to still another embodiment of the present invention, and FIG.
FIG. 13 is a block diagram of an embodiment of the frequency control device forming a part of FIG. 1; 14 and 15 are block diagrams of a control device according to still another embodiment of the present invention, FIG. 16 is a block diagram showing an example of a conventional control device, and FIGS. 17(a) to (g) are FIG. 3 is a waveform diagram of signals in each part of the control device. FIG. 18 is a block diagram showing another example of the conventional control device. 1... Induction machine, 2... Water turbine, 3... Secondary excitation control device. 4... AC system, 5... Water turbine characteristic function generator, 6...
...Rotation speed detector, 10... Guide valve drive device, 11
... Guide valve, 15... Rotation speed command calculator, 16.
...Rotation speed control device.

Claims (1)

[Claims] 1. An induction machine whose primary side is connected to an AC system, and an AC power source connected to the secondary side of the induction machine and which has the same frequency as the AC system in response to an external power generation output command signal. a secondary excitation control device that supplies an excitation current to generate the induction machine, a water wheel that rotationally drives the induction machine, a guide valve that adjusts the amount of water supplied to the water turbine, and an opening of the guide valve. In a variable speed water turbine power generation device comprising a guide valve driving device that controls the degree of rotation according to a guide valve opening command signal, and a rotation speed detector that detects the rotation speed of the induction machine, a power generation output command signal from an external source is used. a calculation means for calculating an optimum rotational speed command by inputting a signal indicating water turbine operating conditions including the above; 1. A control device for a variable speed water turbine power generation device, characterized in that a rotation speed control device is provided to control a guide valve opening degree control signal. 2. In claim 1, the calculation means:
A water turbine characteristic function generator is provided which calculates an optimum guide valve opening command by inputting a signal indicating water turbine operation conditions including at least an external power generation output command signal, and the optimum guide valve opening command signal is used to control the rotation speed. 1. A control device for a variable speed water turbine power generator, characterized in that the control device is configured to input a guide valve opening control signal to the guide valve drive device in addition to a guide valve opening control signal output from the device.