JP2943384B2 - Electric governor for Pelton turbine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a needle and a deflector, and when it is desired to stop a water turbine or reduce its load, a part or all of a jet jet ejected from a nozzle at an opening determined by the needle is deflected. The present invention relates to an electric governor for a Pelton turbine generator of a type that is deflected from a Pelton turbine. In the drawings, the same reference numerals indicate the same or corresponding parts.

[0002]

2. Description of the Related Art As a prior art related to the present invention, there is Japanese Patent Application No. 2-402953 filed by the applicant of the present invention. Fig. 2 shows a different example of a control block diagram of various types of electric governors, in Fig. 2, reference numeral 9 denotes a servo motor provided for each of the first and second groups of needles, and a corresponding motor for driving the corresponding needle; An opening detector 8 for detecting the degree is also a needle opening adjuster for inputting an opening deviation from the corresponding adder 3G and controlling the driving of the corresponding servomotor 9 so that the deviation becomes zero. The adder 3G calculates the deviation between the needle opening command value given from the low value selector 5 and the corresponding opening detection value output from the needle opening detector 10, and the corresponding needle opening adjuster 8
Give to. Reference numeral 17 denotes a servo motor for driving the deflector, 18 denotes an opening detector for detecting the opening of the deflector, 1
Reference numeral 6 denotes a deflector opening adjuster which inputs the opening deviation from the adder 3F and drives and controls the deflector servomotor 17 so that the difference becomes zero. The adder 3F calculates a deviation between the deflector opening command value given from the preceding adder 3E and the opening detection value given from the deflector opening detector 18 and supplies the deviation to the deflector opening adjuster 16.

[0003] Next, 1 is a frequency setting device, 2 is a frequency detector, 3A is an adder for determining the deviation between the set value of the frequency setting device 1 and the detection output of the frequency detector 2, and 4 is an adder for calculating the deviation. This is a PID controller that outputs an opening command value so as to make the speed deviation 0. In this example, the opening command value output from the PID controller 4 is transmitted through a low value selector 5 to a needle opening control system. To the adder 3G). Reference numeral 6 denotes a load limiter which gives an upper limit of the opening. This output value is given to the PID controller 4 and the low value selector 5, and the low value selector 5 outputs the output of the PID controller 4 and the output of the load limiter 6. Any lower value of the needle opening command value is selected and given to the adder 3G. The adder 3B, the rigidity restoration arithmetic unit 12, the divider 11, the load setting unit 7, and the adder 3C are provided to provide the electric governor with a well-known rigidity restoration function (speed drooping characteristic). I have. Next, 13 is a high value selector for selecting which of the first and second groups of needle opening detection values is higher, and 14 is a deflector for finding an appropriate deflector opening corresponding to the selected needle opening detection value. A follow-up operation unit 15 is a frequency rise correction operation unit that obtains a deflector opening correction value from the frequency deviation output from the adder 3A. An adder 3E is provided with an opening command value output from the deflector follow-up operation unit 14 and a correction operation. The deflector opening command value obtained by adding the opening correction value from the device 15 is given to the adder 3F.

Next, in FIG. 3, the opening command value output from the PID controller 4 is given to a deflector control system (an adder 3F thereof) via a low value selector 5, and the needle opening command value is It is provided by a needle following arithmetic unit 14A which inputs the detected value of the opening of the deflector.

That is, this kind of conventional electric governor for Pelton turbines has a single frequency control loop as shown in the control block diagram of FIG. 2 when the turbine is disconnected from the power grid and is operated under no load. A method in which the input is controlled to an optimum opening by a (mainly composed of a PID controller 4), and the deflector normally follows a characteristic opening obtained from the needle opening (needle leading deflector follow-up system: hereinafter abbreviated as "differential follow-up system"). ), Or as shown in the control block diagram of FIG. 3, the deflector is controlled to an optimal opening degree by one frequency control loop (mainly composed of the PID regulator 4) as in FIG. A method of following a characteristic opening obtained from the opening (a deflector leading needle following method: hereinafter abbreviated as a needle following method) is employed.

[0006]

These prior arts have the following problems because the needle and the deflector are controlled by one frequency control loop and the operation of the needle is more than 10 times slower than the deflector. There are drawbacks. In the differential tracking system, in the event of a large disturbance, the frequency rise correction arithmetic unit 1
5 and the adder 3E, the signal polarity is inverted and the signal polarity is reversed and given to the deflector as a correction opening command value to control the deflector opening so as to suppress the frequency increase (that is, from the needle opening to the needle opening). The value obtained from the difference between the characteristic opening obtained through the high value selector 13 and the deflector follow-up computing unit 14 and the opening for correction due to the frequency rise is used as the opening command to the deflector. Since the degree of opening of the deflector is not directly controlled by the signal, it is difficult to obtain a stable control performance. Further, when determining the correction amount, a great deal of labor is required for adjusting the correction calculator 15. That is, if the frequency becomes too high, the differential acts to deflect the water jet hitting the runner by the correction amount. As a result, when the frequency is lowered, the deflector opens again, but at this point, the operation speed of the needle is slow and appropriate. Since the aperture has not been fully closed, the frequency increases again and the deflector closes. As described above, in the differential follow-up method, when the needle opening is larger than the deflector opening, repeated operation is performed, and stable control cannot be performed.

On the other hand, in the needle follow-up system, in a region where the opening of the deflector is small (for example, 2
Since the needle is almost fully closed, controlling the deflector does not affect the frequency. That is, in the low opening region of the deflector, since the needle unresponsiveness is remarkable, it is difficult to obtain stable frequency control performance. Accordingly, it is an object of the present invention to provide an electric governor for a Pelton turbine that can solve these problems and obtain stable frequency control performance.

[0008]

According to a first aspect of the present invention, there is provided an electric speed governor for detecting the opening of a nozzle for jetting a jet stream to a runner of a Pelton turbine generator (needle opening detection). Opening control means (such as a needle opening adjuster 8) that variably controls the insertion and withdrawal of the needle (via the needle servomotor 9 and the like) so that the output of the device 10 becomes equal to the nozzle opening command value. The deflector is deflected so that the direction of the jet water flow is deflected from the direction of the runner (e.g., the output of the deflector opening detector 18) is equal to the deflector opening command value (via the deflector servo motor 17 or the like). Deflector opening control means (such as deflector opening detector 16) for variably operating the attitude, and the first frequency set value (output of frequency setter 1, etc.) A first PID adjusting means for inputting a frequency deviation (via an adder 3A or the like) from a number detection value (such as the output of the frequency detector 2) and outputting the nozzle opening command so that the deviation becomes zero (PID controller 4 and the like) also input the frequency deviation between the second frequency set value and the detected frequency value when the system is cut off, and reduce this deviation to 0.
Second PID adjusting means (PID adjuster 24 or the like) for outputting the deflector opening degree command so that

Frequency set value correcting means (frequency bias setter 21, adder 3H, etc.) for correcting the first frequency set value so that the second frequency set value exceeds the first frequency set value by a predetermined amount. Deflector upper limit opening limiter (deflector upper limiter 14B, low value selector 25, etc.) for limiting the deflector opening command value so as not to exceed a predetermined upper limit corresponding to the opening of the nozzle. Shall be provided.

[0010]

The electric speed governor of the Pelton turbine attempts to stably control the frequency by adjusting the amount of the water jet impinging on the turbine runner with a needle or a deflector. Focusing on working effectively in the region where the frequency deviation is large, independent frequency control loops are provided for the needle and the deflector, respectively. The control signal is not interfered with each other in a region where the speed deviation is large or small, and a control signal that is stable with respect to the set frequency is given to the needle and the deflector. In this case, as described above, the deflector and the needle mainly have different effective frequency deviation regions, and if the frequency setting value is the same, the deflector and the needle compete in the entire deviation region. The frequency setting value given to the deflector is slightly (1 to several%) than that given to the needle.
Make it higher. However, since the deflector frequency setting value is higher than the rated value in the region near the rated frequency, it is expected that the deflector command value will be fully open, so in order to keep this to the optimal opening, the deflector opening command An upper limit limiter for limiting the value is provided. The upper limit opening is given by a characteristic opening curve obtained from the needle opening, and is given as a limit opening at which the deflector does not normally cut off the water jet from the needle.

As described above, the deflector frequency control loop and the needle frequency control loop are made independent and the deflector frequency set value is slightly higher than that for the needle, so that the deflector works effectively in a high speed region. Thus, stable control is performed at a frequency slightly higher than the set frequency of the needle. At this time, the needle is also slowly controlled toward a lower opening so that the frequency is stabilized at a set frequency given from the setter separately from the deflector. As a result, when the needle opening is narrowed and the frequency falls below the frequency set value of the deflector, the signal given to the deflector becomes an open command, but the frequency is controlled by the amount of water limited by the needle opening. Is open, the frequency is no longer affected. On the other hand, since the frequency set value given to the frequency control loop of the needle is lower than that of the deflector, the control of the needle is continued so as to become this value. Further, when the frequency is stable, the opening command value of the deflector is fully opened, but the upper limit is limited to the opening given from the characteristic opening curve at the last stage of the frequency control loop, and the opening is suppressed to the optimum opening. .

[0012]

FIG. 1 is a control block diagram showing the configuration of an embodiment of the present invention. In this figure, the frequency control loop of the needle is equivalent to the loop including the PID controller 4 of FIG. On the other hand, the frequency control loop of the deflector inputs a new frequency deviation as follows and sets this deviation to 0.
Another PI that outputs the deflector opening command value so that
The D adjuster 24 is mainly configured. Here, reference numeral 22 denotes a deflector rigidity restoration calculator for inputting the deflector opening, and 3
H is the output value of the deflector rigidity restoration arithmetic unit 22 from the sum of the frequency deviation (ie, the difference between the set value of the frequency setting unit 1 and the frequency detector 2) as the output value of the adder 3A and the frequency bias setting unit 21. The output value of the adder 3H is provided to the PID controller 24 as a new frequency deviation. Reference numeral 14B denotes a deflector upper limit opening limiter for obtaining an upper limit opening of the deflector from a needle opening detection value output from the high value selector 13. The upper limit opening command value as an output of the limiter 14B is a PID controller 24 and a low value. It is provided to the selector 25. Also, this low value selector 25
A deflector opening command value of the lower value of the output value of the ID adjuster 24 or the output value of the deflector upper limit opening limiter 14B is selected and given to the adder 3F.

As can be seen from FIG. 1, the deflector opening adjustment section is provided with an adder 3F, a deflector opening degree adjuster 16, and a deflector servo motor 17 in the same manner as in a conventional electric governor.
And a deflector opening detector 18 for controlling the deflector servo motor 1 so that the deflector opening matches the opening command value given through the low value selector 25.
7 is controlled. By adding the value of the frequency bias setter 21, the deflector is controlled to have a higher frequency than the value of the frequency setter 1. That is, when the detected frequency is higher than the value obtained by adding the value of the frequency bias setting device 21 to the setting value of the setting device 1, control is performed so that the deflector is narrowed down. Conversely, when the detected frequency is lower than this, control is performed to open the deflector, but when the deflector is opened beyond the position where it does not cut off the water jet from the needle, it does not contribute to frequency control, At this point, the frequency is controlled by the needle to the value of frequency setter 1. Since the frequency controlled by the needle is lower than that controlled by the deflector, the frequency deviation applied to the control loop of the deflector remains positive (+) and the output of the deflector-side PID regulator 24 is
Although the maximum value (full open command value) is obtained, in such a state where the frequency is stable, the upper limit opening is limited by the low value selector 25 by the signal from the upper limit limiter 14B, and the deflector is set to the optimum opening. It is always controlled. The value of the upper limit opening is given by a characteristic opening curve obtained from the needle opening through the high value selector 13.

[0014]

According to the present invention, the frequency control loop for the deflector and the frequency control loop for the needle are independent of each other, and each of them responds separately only by the frequency deviation signal. Since the opening correction amount for such a deflector is not required, and the PID constants of the frequency control loop of the needle and the deflector can be made to match the characteristics of the needle and the deflector, respectively.
The frequency can be stably controlled while performing stable opening control of the needle and the deflector over the entire opening range.

[Brief description of the drawings]

FIG. 1 is a control block diagram as one embodiment of the present invention.

FIG. 2 is a control block diagram as an example of the related art.

FIG. 3 is a control block diagram as another example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frequency setter 2 Frequency detector 3A-3H adder 4 PID adjuster 5 Low value selector 6 Load limiter 7 Load setter 8 Needle opening degree adjuster 9 Needle servo motor 10 Needle opening degree detector 11 Divider 12 Rigidity restoration computing unit 13 High value selector 14B Deflector upper limit opening limiter 16 Deflector opening degree adjustment device 17 Deflector servo motor 18 Deflector opening degree detector 21 Frequency bias setting unit 22 Deflector rigidity restoration operation unit 24 PID controller 25 Low value selection vessel

Claims (1)

(57) [Claims] A nozzle opening control means for variably operating insertion and withdrawal of a needle so that an opening of a nozzle for jetting a jet water flow to a runner of a Pelton turbine generator is equal to a nozzle opening command value; Deflector opening control means for variably controlling the position of the deflector so that the opening of the deflector which deviates the direction of the runner from the direction of the runner is equal to the deflector opening command value. A first PID adjusting means for inputting a frequency deviation from the detected value and outputting the nozzle opening command so that the deviation is set to 0; similarly, at the time of system interruption, a second frequency set value and the frequency detected value A second PID for inputting a frequency deviation of the above and outputting the deflector opening command so that the deviation becomes zero
Adjusting means; frequency setting value correcting means for correcting the first frequency setting value so that the second frequency setting value exceeds the first frequency setting value by a predetermined amount; An electric speed governor for a Pelton turbine, comprising: deflector upper limit opening limit means for limiting the opening so as not to exceed a predetermined upper limit corresponding to the opening.