JPH04334771A - Electric speed governor for pelton wheel - Google Patents

Abstract

PURPOSE:To overcome difficulties in stable control over all opening ranges, which are generated by controlling an opening in a needle (deflector) by one frequency control loop, and making an opening in the other deflector (needle) follow the above opening in the needle (deflector) in conventional system shut- down. CONSTITUTION:A PID controller 24 serving as a frequency controller which gives a deflector opening command is provided together with a PID controller 4 serving as a frequency controller which gives a needle opening command, and a frequency set value to the controller 24 is set to 1% to a higher value by some percentage, adding output of a frequency bias setting device 21 to a set value of the frequency setting device 1 so as to work the frequency control loop of the deflector effectively at the time of excessive external disturbance of frequency rising, especially in system shut-down. There is formed a deflector upper limit opening limiter 14B which outputs the upper limit value of the deflector opening according to the needle opening so that the deflector opening may not exceed its proper limit.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is equipped with a needle and a deflector, and when it is desired to stop a water turbine or reduce its load, the deflector deflects part or all of the jet stream ejected from a nozzle at an opening determined by the needle. This invention relates to an electric speed governor for a Pelton turbine generator that is deflected from a Pelton turbine. Note that in the following figures, the same reference numerals indicate the same or corresponding parts.

0002

[Prior Art] As a prior art related to the present invention, there is Japanese Patent Application No. 2-402953, which is an earlier application filed by the present applicant. 2 shows different examples of control block diagrams of electric speed governors. In FIG. 2, 9 is a servo motor provided for each of the first and second groups of needles and drives the corresponding needle, and 10 is a servo motor for opening the corresponding needle. The opening detector 8 is a needle opening adjuster which inputs the opening deviation from the corresponding adder 3G and drives and controls the corresponding servo motor 9 so as to set this deviation to zero. Note that the adder 3G calculates the deviation between the needle opening command value given from the low value selector 5 and the opening detected value output from the corresponding needle opening detector 10, and supplies it to the corresponding needle opening regulator 8. Further, 17 is a servo motor that drives the deflector, 18 is an opening detector that detects the opening of the deflector, and 16
is a deflector opening degree adjuster which inputs the opening degree deviation from the adder 3F and drives and controls the deflector servo motor 17 so as to set this difference to zero. Note that the adder 3F calculates the deviation between the deflector opening command value given from the adder 3E in the previous stage and the opening detected value given from the deflector opening detector 18, and supplies the deviation to the deflector opening adjuster 16.

Next, 1 is a frequency setter, 2 is a frequency detector, and 3A is a set value of this frequency setter 1 and a frequency detector 2.
4 is this adder 3 for calculating the deviation from the detection output of
P outputs the opening command value so that the speed deviation is 0 from A.
An ID controller, in this example, a PID controller 4 outputs an opening command value which is applied to the needle opening control system (adder 3G) via a low value selector 5. Note that 6 is a load limiter that gives an upper limit to the opening degree, and this output value is given to the PID regulator 4 and low value selector 5. The needle opening command value having the lower value is selected and given to the adder 3G. Also, adder 3B, rigidity restoration calculator 12, divider 11, load setting device 7
, adder 3C are provided to provide this electric speed governor with a well-known rigidity restoring function (speed drooping characteristic). Next, 13 is a high value selector that selects the higher value of the needle opening detection values of the first group or the second group, and 14 is a deflector that determines the appropriate deflector opening corresponding to the selected needle opening detection value. The tracking calculator 15 is a frequency increase correction calculator that calculates the deflector opening correction value from the frequency deviation output from the adder 3A, and the adder 3E calculates the opening command value output from the deflector tracking calculator 14 and the correction calculation. vessel 15
A deflector opening command value obtained by adding the opening correction value from .

Next, in FIG. 3, the opening command value output from the PID controller 4 is given to the deflector control system (adder 3F) via the low value selector 5, and the needle opening command value is It is given by the needle follow-up calculator 14A which inputs the detected value of the opening of the deflector.

That is, in the conventional electric speed governor for a Pelton water turbine of this type, during no-load operation when the water turbine is disconnected from the power grid, one frequency control loop is used as shown in the control block diagram of FIG. (Mainly consisting of PID controller 4), the input is controlled to the optimum opening, and the deflector normally follows the characteristic opening obtained from the needle opening. ), or as shown in the control block diagram of FIG. 3, the deflector is controlled to the optimum opening degree from one frequency control loop (mainly consisting of the PID controller 4) as in FIG. 2, and the needle is normally connected to the deflector. A method of following the characteristic opening obtained from the opening (deflector preceding needle following method: hereinafter abbreviated as needle following method) is adopted.

[0006]

[Problems to be Solved by the Invention] These conventional techniques have the following problems because the needle and deflector are controlled by one frequency control loop, and the operation of the needle is more than 10 times slower than that of the deflector. There are drawbacks. In the differential tracking method, in the event of a large disturbance, the frequency increase correction calculator 15
Then, through the adder 3E, the signal polarity is reversed for only the frequency increase, and the signal is given to the deflector as a correction opening command value, thereby controlling the deflector opening to throttle the frequency increase (i.e., from the needle opening to a high value). The value obtained from the difference between the characteristic opening degree obtained via the selector 13 and the deflector tracking calculator 14 and the opening degree corrected by the frequency increase is used as the opening degree command to the deflector), and a signal from the frequency control loop. Since the deflector opening degree is not directly controlled, it is difficult to obtain stable control performance, and also when determining the correction amount, a great deal of effort is required to adjust the correction calculator 15. In other words, when the frequency becomes too high, the differential works to deflect the water jet hitting the runner by the amount of correction, and as a result, when the frequency decreases, the deflector opens again, but at this point, the needle operating speed is slow enough to prevent the water jet from hitting the runner. Since the opening has not been fully closed, the frequency will rise again and the deflector will close again. In this way, with the differential tracking system, when the needle opening is larger than the deflector opening, the system repeats operation and cannot provide stable control.

On the other hand, in the needle tracking method, in a region where the deflector opening is small due to the characteristic opening (for example, 2
Since the needle is almost fully closed, controlling the deflector does not affect the frequency. That is, in the low opening range of the deflector, the refractory movement of the needle is significant, making it difficult to obtain stable frequency control performance. SUMMARY OF THE INVENTION An object of the present invention is to provide an electric speed governor for a Pelton water turbine that can solve these problems and provide stable frequency control performance.

[0008]

[Means for Solving the Problems] In order to solve the above-mentioned problems, an electric speed governor according to claim 1 is provided with Nozzle opening control means (needle opening adjuster 8, etc.) that variably operates the insertion and withdrawal of the needle (via needle servo motor 9, etc.) so that the output of the detector 10, etc.) becomes equal to the nozzle opening command value. , the deflector is controlled (via the deflector servo motor 17, etc.) so that the opening degree of the deflector that deflects the direction of the jet water flow from the direction of the runner (output of the deflector opening degree detector 18, etc.) is equal to the deflector opening degree command value. Deflector opening degree control means (deflector opening degree detector 16, etc.) that variably manipulates the attitude of the a first PID adjustment means (PID controller 4, etc.) that inputs a frequency deviation (via an adder 3A, etc.) with respect to the output (e.g., output) and outputs the nozzle opening command value so as to set this deviation to 0; Similarly, when the system is shut off, a second PID adjustment means (PID adjustment) inputs a frequency deviation between the second frequency setting value and the frequency detection value and outputs the deflector opening command value so as to set this deviation to 0. (24 etc.) shall be provided, and

In the electric speed governor according to claim 1, the second frequency setting value exceeds the first frequency setting value by a predetermined amount. Frequency setting value correction means (
frequency bias setter 21, adder 3H, etc.), deflector upper limit opening limiting means (deflector upper limit opening) that limits the deflector opening command value so that it does not exceed a predetermined upper limit corresponding to the nozzle opening. limiter 14B, low value selector 25, etc.).

0010

[Operation] The electric speed governor of a Pelton turbine attempts to stably control the frequency by adjusting the amount of water jet hitting the turbine runner with a needle or deflector, but the deflector mainly controls the frequency from the rated frequency. Focusing on the fact that it works effectively in areas with large frequency deviations, independent frequency control loops are provided for the needle and deflector. The configuration is such that a control signal that is stable with respect to the frequency setting value is provided to the needle and the deflector without interfering with each other even in areas where the speed deviation is large or small. In this case, as mentioned above, the deflector and needle mainly operate in different frequency deviation ranges, and if the frequency settings are the same, the deflector and needle will compete in the entire deviation range. , the frequency setting value given to the deflector is slightly (1 to several%) higher than that given to the needle.
Make it expensive. However, in the area near the rated frequency, the deflector frequency setting value is higher than the rated value, so the deflector command value is expected to be fully open. Provide an upper opening limiter to limit the value. This upper limit opening degree is given by a characteristic opening degree curve obtained from the needle opening degree, and is given as the limit opening degree at which the deflector does not cut off the water jet from the needle under normal conditions.

[0011] By making the frequency control loop for the deflector and the frequency control loop for the needle independent in this way, and setting the frequency setting value for the deflector slightly higher than that for the needle, the deflector acts effectively in the high speed region. , stable control is performed at a frequency slightly higher than the set frequency of the needle. At this time, apart from the deflector, the needle is also slowly controlled toward a lower opening degree so as to stabilize the frequency at the set frequency given by the setter. As a result, when the needle opening is narrowed and the frequency drops below the deflector frequency setting, the signal given to the deflector becomes an open command, but since the frequency is controlled by the amount of water limited by the needle opening, the deflector Even if the circuit is open, the frequency is no longer affected. On the other hand, since the frequency setting value given to the frequency control loop of the needle is lower than that of the deflector, control of the needle is continued to maintain this value. Furthermore, when the frequency is stable, the deflector opening command value is fully open, but at the final stage of the frequency control loop, the upper limit is limited to the opening given from the characteristic opening curve, and the opening is kept at the optimum opening. .

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a control block diagram showing a configuration as an embodiment of the present invention. In the figure, the needle frequency control loop is equivalent to the loop including the PID regulator 4 of FIG. On the other hand, the frequency control loop of the deflector inputs a new frequency deviation and converts this deviation to 0.
Another PI that outputs the deflector opening command value as follows.
It is mainly composed of the D adjuster 24. Here, 22 is a deflector rigidity restoration calculator that inputs the deflector opening degree;
H is the output value of the deflector stiffness restoration calculator 22 from the sum of the frequency deviation (i.e., the difference between the setting value of the frequency setter 1 and the frequency detector 2) as the output value of the adder 3A and the frequency bias setter 21. An adder performs subtraction, and the output value of this adder 3H is given to the PID adjuster 24 as a new frequency deviation. Further, 14B is a deflector upper limit opening limiter which determines the upper limit opening of the deflector from the needle opening detection value outputted from the high value selector 13, and the upper limit opening command value as the output of this limiter 14B is set by the PID controller 24 It is given to the selector 25. Also, this low value selector 25 is P
The deflector opening command value which is 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 includes an adder 3F, a deflector opening adjustment device 16, and a deflector servo motor 17, similar to the conventional electric speed governor.
and a deflector opening degree detector 18, and the deflector servo motor 1
Control 7. 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 sum of the set value of the setter 1 and the value of the frequency bias setter 21, the deflector is controlled to narrow down. Conversely, when the detected frequency is lower than this, the deflector is controlled to open, but when the deflector opens beyond the position where it does not cut off the water jet from the needle, it no longer contributes 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 imparted to the control loop of the deflector remains positive (+) and the output of the PID regulator 24 on the deflector side is However, when the frequency is stable, the upper limit opening is limited by the low value selector 25 using the signal from the upper limit opening limiter 14B, and the deflector is set to the optimum opening. Constantly controlled. Further, the value of the upper limit opening degree is given by a characteristic opening degree curve obtained from the needle opening degree passed through the high value selector 13.

[0014]

[Effects of the Invention] 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 responds separately only in response to the frequency deviation signal. There is no need for an opening correction amount for the deflector, and the PID constants of the frequency control loops of the needle and deflector can be adjusted to match the characteristics of the needle and deflector, respectively.
The frequency can be stably controlled while performing stable opening control over the entire opening range of the needle and deflector.

[Brief explanation of drawings]

FIG. 1: Control block diagram as an embodiment of the present invention

[Figure 2] Control block diagram as an example of conventional technology

[Fig. 3] Control block diagram as another conventional example

[Explanation of symbols]

1 Frequency setter 2 Frequency detectors 3A to 3H Adder 4 PID controller 5 Low value selector 6 Load limiter 7 Load setter 8 Needle opening adjuster 9 Needle servo motor 10 Needle opening detector 11 Divider 12 Rigidity restoration calculator 13 High value selector 14B Deflector upper limit opening limiter 16 Deflector opening adjuster 17 Deflector servo motor 18 Deflector opening detector 21 Frequency bias setter 22 Deflector rigidity restoration calculator 24 P
ID adjuster 25 Low value selector

Claims (2)

[Claims] 1. A nozzle opening degree control means for variably operating the insertion and withdrawal of a needle so that the opening degree of a nozzle that spouts a jet water stream to a runner of a Pelton turbine generator is equal to a nozzle opening command value, the jet water stream deflector opening control means for variably manipulating the attitude of the deflector so that the opening of the deflector that deflects the direction of the runner from the direction of the runner is equal to the deflector opening command value; A first PID adjustment means inputting a frequency deviation from the detected value and outputting the nozzle opening command value so as to set this deviation to 0; An electric speed governor for a Pelton water turbine, characterized in that the electric speed governor for a Pelton water turbine is provided with a second PID adjusting means for inputting a frequency deviation between the two and outputting the deflector opening command value so as to set the deviation to zero. 2. The electric speed governor according to claim 1, wherein the first frequency setting value is corrected so that the second frequency setting value exceeds the first frequency setting value by a predetermined amount. For a Pelton water turbine, comprising a set value correction means and a deflector upper limit opening limit means for limiting the deflector opening command value so that it does not exceed a predetermined upper limit corresponding to the opening of the nozzle. Electric speed governor.