JPS6149514B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling a water turbine generator using an electric governor, and in particular, by providing a closing speed control loop that controls the closing speed of the guide vane when the load is off, The object of the present invention is to provide a control method that can obtain desired closing speed characteristics and smoothly transition from startup to steady operation or from steady operation to load shedding.

Generally speaking, it is well known that an electric governor is used to automatically control the speed of a water turbine generator to a certain desired value according to a predetermined speed regulation rate when load fluctuations occur. It is. A conventional device shown in FIG. 1 to which this type of electric governor is applied will be explained. In the figure, 1 is a pilot generator that detects the rotation speed of the water turbine generator, 2 is a pilot generator that converts the frequency signal of the pulse train input to the F/V conversion circuit into a DC level voltage signal, and 3 is a pilot generator that detects the rotation speed of the water turbine generator. A speed control amplifier that amplifies the deviation between the speed setting command signal, the speed detection signal that is fed back, the elastic restoring signal that determines the transient adjustment rate and time constant, and the rigid restoring signal that determines the adjustment rate, and 4 is a limiter circuit. This is to limit the maximum closing speed or opening speed of the guide vane, and 5 is a converter (not shown), inside which a moving coil is inserted to convert an electrical signal into a mechanical displacement signal. 6 is a pressure regulating valve which is connected to the converter via an operating shaft ₆₁ , and is used to send out pressurized oil through pipes ₆₂ and ₆₃ , which is input in any vertical direction of this operating shaft.
7 is a servo motor into which a piston ₇₁ and a piston rod ₇₂ are inserted, and when pressure oil enters through a pipe ₆₂ , it operates a guide vane of a water turbine (not shown) in the "open" direction, and vice versa. When pressure oil enters through the pipe ₆₃ , the guide vane is operated in the "close" direction. 8 is a stroke amount detection circuit for detecting the stroke amount of the piston rod to extract a signal related to the opening degree of a guide vane of a water turbine (not shown); 9 ₁ is a circuit that detects the stroke amount of the piston rod and extracts a signal related to the opening degree of a guide vane of a water turbine (not shown); Similarly, ₉₂ is a rigid restoring amount generation circuit that generates an elastic restoring signal that determines the transient adjustment rate and time constant according to the input opening detection signal. Each of these generating circuits suppresses excessive opening/closing operations of the guide vanes that occur during speed fluctuations due to load changes.
10 is a speed regulator, which has a built-in circuit that generates a speed adjustment curve such that the relationship between the generator output frequency and the generator output becomes non-linear when the lines are parallel, and also provides a speed setting command amount. It also has a built-in circuit. Reference numeral 11 denotes a starting device, which has built-in setting devices for supplying a starting opening setting command signal, a no-load opening setting command signal, and a load opening setting command signal, respectively, and 12 ₁ to 12 ₄ are comparison circuits, respectively. For example, when the water turbine starting command is input, the circuit ₁₂₁ operates to directly lead the signal output from the elastic restoring amount generating circuit ₉₁ to the comparison circuit ₁₂₂ in the subsequent stage, and _also The circuit compares the speed setting signal from the speed regulator 10 with a restoring signal obtained by adding the signal from the rigid restoring amount generating circuit ₉₂ and the signal from the elastic resting amount generating circuit ₉₁ , and further The circuit ₁₂₃ calculates the deviation between the speed setting signal derived from the comparator circuit ₁₂₂ and the restoring signal;
An operation is performed to compare the speed detection signal derived from the F/V conversion circuit 2, and therefore, the ₁₂₃ comparison circuit compares the speed setting signal, the feedback speed detection signal, and each restoring signal with the signal. The deviation will be extracted. Reference numeral 13 denotes an opening control amplifier for amplifying the opening deviation derived from the comparator circuit ₁₂₄ . Reference numeral 14 denotes a mechanical stopper inserted into the operating shaft _61. This stopper adjusts the closing speed of the guide vane (not shown) so that the water pressure in the penstock pipe and the rotation speed of the water wheel do not rise above a predetermined value when the load is cut off. _S1 , _S2 , and _S3 are contacts that close when the starting opening setting command signal, no-load opening setting command signal, and load opening setting command signal are respectively given. be. The operation of the conventional device configured in this way is, for example, when starting a water turbine generator, first, the starting opening setting command amount is applied from the starting device 11 through the contact S ₁ , and at the same time a speed setting command signal is sent. The speed regulator 1
If 0 is applied to the speed control loop, the water turbine has not started yet, so the speed detection signal and opening detection signal that are fed back are 0. For example, the speed setting voltage output from the speed control amplifier 3 is higher than the starting voltage. Since the voltage level is higher than the opening opening setting voltage, the opening command signal output from the limiter circuit 4 is limited to the value of the starting opening opening setting voltage, and the opening command voltage thus limited is used to control the opening opening setting voltage. Comparison circuit 12
₄ → amplifier 13 and converter 5 of the servo control mechanism → pressure distribution valve 6 → servo motor 7, and the water turbine is started by controlling the opening degree of a guide vane (not shown) in the opening direction. As the opening of the guide vanes gradually increases, the water turbine generator is accelerated, but at the beginning of startup, the signal voltage output from the speed control amplifier 3 is higher than the limit voltage value, which is the starting opening setting voltage. Since the limit voltage is still large, the limit voltage is directly guided to the opening control amplifier and then to the servo control mechanism to perform predetermined opening control. By performing such control, for example, when the starting opening setting voltage and the guide vane opening detection signal become equal,
Next, by giving a no-load opening setting command signal from the starting device 11, the opening of the guide vane (not shown) is automatically controlled via the speed control loop, opening control loop, and servo control mechanism. When the opening of the guide vane becomes equal to the no-load opening setting command signal, a predetermined load opening setting command signal is given to control the governor operation (speed control) performed during steady state rather than opening opening control at startup. or rotation speed control). Note that during governor operation, only contact _S3 is closed and a load opening command is given. During such governor operation,
If the need to perform load shedding arises for some reason, a problem with conventional devices is adjusting the closing speed of the guide vane during this kind of load shedding. To describe the situation during load interruption in detail with reference to the time chart in Figure 2, if the speed setting command voltage is reduced to zero at point _t0 in Figure 2 as shown in Figure 2A. For example, as shown in FIG. 2C, the opening degree of the guide vane of the water turbine is suddenly operated in the fully closed direction via the speed control loop, the opening degree control loop, and the servo control mechanism to perform load shedding. If such a load shedding operation method is used, as is conventionally known, the rotational speed of the water turbine will rise rapidly immediately after the load shedding, as shown after point _t0 in Figure 2B, and similarly, the water pressure in the penstock will also rise at the second point. As shown after point _t0 in Figure D, the water pressure increases rapidly, and the degree of increase in the water turbine rotation speed and water pressure is greatly influenced by the closing speed T of the guide vane shown in Figure 2C. In other words, if the closing speed is increased, the rate of increase in water pressure will be proportionally higher.
On the contrary, the rate of increase in the rotational speed of the water turbine decreases. On the other hand, if the closing speed is slowed down, the rate of increase in water pressure will be lower, but the rate of increase in the rotational speed of the water turbine will be higher.Therefore, water pressure and rotational speed are in a contradictory relationship. A mechanical stopper 14 that adjusts the closing speed of the guide vane in order to suppress both the rise and the increase in the rotational speed of the water turbine within a predetermined range.
It is inserted between converter 5 and pressure regulating valve 6 shown in FIG. Such a mechanical stopper has, for example, a hole of a predetermined diameter passing through it so that the operating shaft ₆₁ can freely move up and down, and the stopper 14
It is also structured so that it can be moved up and down along the operating shaft ₆₁ . On the other hand, a protrusion is provided at an arbitrary part of the operating shaft ₆₁ , and when this protrusion comes into contact with the stopper 14, the operating shaft ₆₁ moves to the stopper 14.
The structure is such that it cannot move toward the pressure regulating valve 6 side from the position. Therefore, by adjusting the position where the stopper 14 is fixed, the amount of oil supplied to the servo motor 7 from the pressure distribution valve 6 is adjusted, and thereby the piston 7 ₁ of the servo motor 7 moves to the fully closed position. The operating time, ie the closing speed of the guide vanes (not shown), can be adjusted. In this way, the closing speed of the guide vane is adjusted by maintenance personnel by adjusting the fixed position of the stopper, so in order to obtain the optimum closing speed, the fixed position of the stopper must be adjusted to approximately T/10.
Adjustments must be made on the order of millimeters to approximately 1/100 millimeters, which is extremely difficult work and causes a great deal of maintenance trouble. What is especially important is that
Even if the fixed position of the stopper is set to obtain the desired closing speed, the fixed position of the stopper may shift due to aging of the mechanical system, resulting in various problems such as an abnormal increase in water pressure or an abnormal increase in the rotational speed of the water wheel. There is.

The present invention provides elasticity according to the speed setting signal, the speed detection signal and the opening detection signal that are fed back.
The maximum output value of the speed control amplifier of the speed control loop is determined using the opening setting signal from the speed control loop that performs predetermined speed control based on three quantities including the stiffness restoring signal and the opening setting loop. a limiter circuit that limits the limited signal and uses the limited signal as an opening command; an opening control loop that controls a servo control mechanism that makes the deviation between the opening command signal from this circuit and the opening detection signal similar; The maximum output value of the speed control amplifier is limited using a signal obtained by amplifying the deviation between the closing speed setting signal and the closing speed detection signal corresponding to the input opening detection signal, and this limited signal is used to control the opening. It is equipped with a closing speed control loop for commands and a servo control mechanism for operating the guide vane based on the opening command signal given from the closing speed loop. 3: degree setting loop, opening control loop, servo control mechanism
The opening degree of the guide vane is controlled through two control loops, and when the load is cut off, the opening degree of the guide vane is controlled through the speed control loop, the opening control loop, the closing speed control loop, and the servo control mechanism control loop. and the closing speed of the guide vane. A detailed description will be given below based on an embodiment of the present invention shown in FIG. Components in the embodiment shown in FIG. 3 that are the same as those in FIG. 1 are given the same reference numerals.
Reference numeral 15 denotes a closing speed detection circuit for detecting the closing speed of the guide vane. Although the configuration of this circuit is not shown, the closing speed can be obtained by differentiating the stroke detection amount obtained by detecting the stroke of the piston rod ₇₂ , for example. Either the closing speed can be used as is, or furthermore, a rack of a predetermined length can be provided at an arbitrary part of the piston rod ₇₂ , and a small generator for speed detection can be attached to the pinion that rotates on this rack. A more desired closing speed signal may be extracted. 16 is a closing speed setting circuit, and the configuration of this circuit is, for example, as shown in FIG. 4, an arbitrary number of setter groups VR ₁ to VRn and contact groups S ₄ to
By setting the sliding position of each setter at an appropriate position in advance and combining it with the contact group, a desired closing speed command voltage can be obtained. In addition to this configuration, for example, although not shown, there is a so-called "function generator" that uses a high-gain amplifier and connects series circuits of diodes and resistors in multiple stages in parallel to the return loop of this amplifier. You may use what is provided. 17 is a comparison circuit that compares the closing speed command signal and the closing speed detection signal, 18 is an amplifier circuit that amplifies the deviation obtained by this circuit, and the limit voltage of the limiter circuit 4 is automatically adjusted using this amplified signal. Care has been taken in advance to ensure that the regulations are regulated accordingly. Ms is a contact that is closed at a predetermined load or stage.

To explain in detail the operation of one embodiment of the present invention configured as described above, the steady operation of starting the water turbine generator and controlling the acceleration to the rated rotation speed is performed by contact Ms
is in an open state, so in the initial stage of startup, the limit voltage of the limiter circuit 4 is set by the startup opening command voltage from the opening setting loop guided through the contact _S1 , just like the conventional device shown in Fig. 1. Since it is set,
The maximum output value of the speed control amplifier, which amplifies the deviation between the speed setting voltage and each restoration signal corresponding to the speed detection signal and opening detection signal that are input with the opposite polarity to this voltage, is limited to the limit voltage. Based on this limited opening command voltage, the opening of the guide vane (not shown) is controlled via the opening control amplifier 13 and a servo control mechanism including the converter 5, and the water turbine control the acceleration.
When the guide vane opening reaches the starting opening setting voltage, the starting opening setting signal is canceled and a new contact S ₂ is opened.
The no-load opening setting voltage is input through , and this no-load opening setting voltage is a potential that gives a smaller change in opening than that caused by the starting opening setting voltage, so this changes the guide vane opening. It is gradually closed from the starting opening position to a position corresponding to the no-load opening position. On the other hand, the water turbine speed is gradually accelerated and controlled to increase to the rated rotation speed as the guide vanes are opened. When the speed of the water turbine is accelerated to near the rated rotational speed in this way, the output voltage of the speed control amplifier finally becomes smaller than the limit voltage, and the output voltage of the speed control amplifier itself is no longer limited by the limit voltage. Therefore, the output voltage of the speed control amplifier is directly applied to the opening control amplifier 13 and then to the servo control mechanism, and the guide vane is gradually closed to the no-load opening position. This operating state is called governor-free, and in the governor-free state, by canceling the no-load opening setting signal and inputting the load opening setting signal through contact S ₃ , the steady state can be changed. This will cause the system to shift to governor operation. Next, see the fifth section regarding the operation when the load is interrupted.
To explain in detail with reference to the time chart shown in the figure, Figure 5A shows the closing speed of the guide vane over time, and at the same time, Figures 5B and C show the closing speed setting voltage and limiter circuit over time. Each limit voltage is shown. Now, when the load cutoff command is input, the contact Ms shown in Fig. 3 closes, and at the same time, the contact _S5 which gives the load opening setting voltage
is opened, thereby opening the opening setting loop that applies the opening setting voltage to the limiter circuit 4, and furthermore, a zero speed command is input from the speed regulator 10 to set the speed of the water turbine generator (not shown) to zero. be done. In parallel with this operation, the closing speed setting circuit shown in FIG. 4 uses the setting device VR ₁ to set a set voltage corresponding to the O-t ₁ period in FIG. - Similarly, _the set voltage corresponding to _the period t ₁ - t ₂ in _{FIG .}
- the path of the contact S ₆ , and the setting voltage corresponding to the period t ₂ - _{t 3} of FIG. Therefore, when a predetermined load cutting command is input, the closing speed of the guide vane is first detected by the closing speed detection circuit 15 based on the stroke detection signal obtained by the stroke detection circuit 8, and then the closing speed of the guide vane is detected by the closing speed detection circuit 15. In parallel, the closing speed setting voltage is set based on the stroke detection signal VR ₁ - contact
It leads to the comparator circuit 17 in FIG. 3 via the path _S4 . However, during the transition period when the load-off command is input, the closing speed detection signal value is at zero level, so this closing speed detection signal and the closing speed setting voltage shown in the O-t ₁ period in Fig. 5B are The determined limit voltage of the limiter circuit 4 in FIG. 3 is set to the maximum level as shown in period O- _t1 in FIG. 5C.

When the above-mentioned zero speed setting signal is input to the speed control loop in such a state, the speed detection signal derived from the F/V conversion circuit 2 is at the maximum level, and the opening degree of the guide vane is detected by the stroke detection circuit 8. Since the signal is at the maximum level, the comparator circuit ₁₂₃ compares the three quantities of the zero speed setting signal, the speed detection signal, and each restoring signal corresponding to the opening detection signal, and the circuit ₁₂₃ then outputs the speed control amplifier 3. The signal guided by is the maximum command to reduce the rotation speed of the water turbine to zero speed. This signal is once amplified by the speed control amplifier 3 and given to the limiter circuit 4. In the limiter circuit 4, the output voltage of the speed control amplifier 3 is higher than the limit voltage determined by the output voltage of the amplifier circuit 18. Under this condition, the output voltage of the amplifier 3 is limited to a limit voltage value. The opening degree of the guide vane (not shown) is controlled by the servo control mechanism including the converter 5 using the opening command voltage thus limited. The closing speed characteristic diagram in FIG. 5A shows the closing process of the guide vane in response to speed.
It can be seen that after the load reduction command is input, the closing speed for reducing the opening of the guide vane increases rapidly as the opening is closed, as shown in the O-t ₁ period of FIG. 5A. Note that as the opening degree of the guide vane gradually closes, the closing speed based on the stroke detection signal is detected through the detection circuit 15, and the deviation between the closing speed setting signal and the closing speed detection signal gradually becomes smaller. In response to this, the limit voltage of the limiter circuit 4 is lowered, so that the guide vane is gradually closed via the opening control amplifier 13 and the servo control mechanism in accordance with the opening command of this limit voltage. The closing speed of the guide vane is automatically controlled via the closing speed control loop to accelerate the closing speed only during the beginning of the loading stage as shown in the O-t ₁ period of Figure 5A. Close the opening. Now, when the opening degree of the guide vane is closed to the predetermined opening position (point t ₁ in Figure 5 C), under this condition, the contact point S ₄ in Figure 4 is closed.
is opened, and in parallel with this, a closing speed setting voltage as shown in the period t ₁ to _{t 2} of FIG. 5B is inputted through contacts S ₅ and S ₆ . A limit voltage is newly set based on the deviation between this closing speed setting voltage and the closing speed detection signal, and the level of this newly set limit voltage is t ₁ - t ₂ in FIG. 5C.
As shown in the period, the potential itself is lower than at the initial stage of closing, so the range of the amount of change in the opening of the guide vane as it is closed via the servo control mechanism is relatively reduced, and the closing speed itself at which the opening is closed is lowered. is automatically controlled via a closed speed control loop and gradually decreases as shown in the t ₁ -t ₂ period of FIG. 5A. Now, the opening degree of the guide vane is further closed and approaches the fully closed position (as shown in Figure 5 C).
t ₍₂ points shown), the speed of the water turbine rapidly decreases according to this opening position, and the deviation between the zero speed setting signal, the speed detection signal, and the righting signal corresponding to the opening detection signal also gradually decreases. I'll go. After confirming that the guide vane has been closed to the predetermined position based on the stroke detection signal, the contact point Sn-t in Fig. 4 is confirmed.
The closing speed setting voltage as shown in the period t ₂ - t ₃ in FIG. The limit voltage corresponding to the deviation is set again, and the closing speed at which the guide vane is closed based on this limit voltage is then set to the command voltage shown in the period t ₂ - t ₃ in FIG. 5B. The opening of the guide vane is automatically controlled to the fully closed position.

Similarly, contact Sn in Figure 4 closes and the setting device
Closing speed setting voltage given by VRn (Fig. 5B
The closing _speed , which narrows down the opening of the guide vane to the fully closed position, is automatically controlled based on the limit voltage determined by the deviation between the closing speed detection signal and the closing speed detection signal.

In the above explanation, a specific example was described in which the closing speed setting circuit 16 sequentially outputs the required closing speed setting signal from each variable resistor alone. Instead of outputting the closing speed setting signal, for example, the first closing speed command amount is VR ₁ using the variable resistor group shown in Figure 4.
The output is the combination of VR ₃ and the second closing speed command is the output of the combination of VR ₂ and VR ₅ . By appropriately outputting the closing speed command amount, there is an advantage that the closing speed characteristics themselves can be made closer to ideal characteristics.

As described above, the present invention includes a speed control loop, a limiter circuit that limits the output value of a speed control amplifier based on the start, no-load, and load opening setting signals,
an opening control loop that controls the opening based on the opening command signal and the opening detection signal of the circuit; and limiting the output value of the speed control amplifier based on the closing speed setting signal and the closing speed detection signal. a closed speed control loop that
A control device is configured with a servo control mechanism that operates the guide vane, and when the guide vane is operated in the opening direction, it is controlled via a speed control loop, an opening degree setting loop, an opening degree control loop, and a servo control mechanism, and a predetermined When the load is cut off, the guide vane is controlled in the closing direction via the speed control loop, the closing speed control loop, the opening control loop, and the servo control mechanism, so various effects are achieved as shown below. It is something.

Since the closing speed is automatically controlled purely electrically, rather than relying on a mechanical stopper as seen in the past, the closing speed characteristic itself can be adjusted freely by arbitrarily varying the closing speed setting command amount. , the desired closing speed characteristics can be easily obtained.

Due to the above reasons, the oil temperature of the servo system pressure oil,
It is possible to maintain a stable closing speed without changing the closing speed characteristics due to aging of the hydraulic pressure or mechanical system, and to limit increases in water pressure and water turbine rotation speed during load shedding to within a desired range.

When giving the required closing speed setting command amount, it can be easily programmed, and in conjunction with this programming, it has the characteristic that it is not affected by pressure oil in any way, so it is possible to make the power plant unmanned. We can provide an optimal device that can take full advantage of its features.

The opening command given to the servo control mechanism is automatically adjusted by the deviation between the setting signal and the detection signal from the startup of the water turbine generator to the cabana operation during steady state and load shedding. A smooth transition from load shedding to operation can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a concrete block configuration diagram showing a conventional device, Fig. 2 is a time chart showing its operation,
FIG. 3 is a specific block configuration diagram showing one embodiment of the present invention, FIG. 4 is a specific circuit example showing a closing speed setting circuit according to the present invention, and FIG. A time chart diagram showing the operation of. 1 is a pilot generator, 2 is an F/V conversion circuit,
3 is a speed control amplifier, 4 is a limiter circuit, 5
is a converter, 6 is a pressure distribution valve, 7 is a servo motor,
8 is a stroke detection circuit, 9 ₁ is an elastic restoring amount generation circuit, 9 ₂ is a rigid restoring amount generation circuit, 10 is a speed regulator, 11 is a starting device, 12 ₁ to 12 ₄ and 17
is a comparison circuit, 13 is an opening control amplifier, 15 is a closing speed detection circuit, 16 is a closing speed setting circuit, Ms
is a switch.

Claims (1)

[Claims] 1 A speed control loop that performs speed control based on a speed setting signal, a speed detection signal, and a restoring signal according to an opening detection signal, and a starting opening setting signal, a no-load opening setting signal, and a load opening setting signal. An opening control device that limits the output of the speed control amplifier of the speed control loop based on the three types of opening setting signals respectively set from each setting device to determine the opening control amount in the opening direction of the guide vane. The following is the deviation between the closing speed setting signal that sets the closing speed of the guide vane based on the opening detection signal, and the detection signal that detects the closing speed of the guide vane based on the opening detection signal. a closing speed control loop that limits the output of the speed control amplifier to determine the opening control amount in the closing direction of the guide vane; and the opening control amount;
an opening control loop that controls the opening of the guide vane based on the deviation from the opening detection signal; and a servo control mechanism that operates the guide vane in the opening or closing direction using the output signal of this control loop. When operating the guide vane in the opening direction, the opening is controlled through each control loop of the speed control loop, the opening setting loop, the opening control loop, and the servo control mechanism, When operating the guide vane in the closing direction, the opening degree is controlled through each control loop of the speed control loop, the closing speed control loop, the opening degree control loop, and the servo control mechanism. How to control a water turbine generator.