JPH02308974A - Speed control device for water turbine - Google Patents

Abstract

PURPOSE:To perform smooth starting control by adjusting the opening of a guide vane at the adequate limit opening corresponding to the effective head. CONSTITUTION:A loss head arithmetic unit 13 calculates the actual flow from the guide vane opening signal theta obtained by a position detector 10 and the effective head signal (h) obtained by an adder 14 and calculates the loss head for this actual flow. The loss head signal obtained by the arithmetic unit 13 is inputted to the adder 14 together with the discharge port water level signal and the upper dam water level signal obtained by water level detectors 11 and 12 and outputted as the effective head signal (h). The signal (h) is also inputted to a start signal generator 15 and a load upper limit signal generator 16, and the start opening command signal and the load upper limit signal suitable for the effective head (h) are calculated and inputted to a load limiter 6. When the effective head is large, the output thetaL of the load limiter 6 is reduced to suppress the over-speed, when the effective head is small, the output thetaL of the limiter 6 is increased, and such a state is prevented that no rated speed is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a speed governor control device for a water turbine suitable for a hydroelectric power plant with a large variable head.

(Prior Art) Generally, when starting a water turbine, the load limiter is controlled to the starting opening and 1. In this case, a speed governor control device is used that opens the guide vane to the starting opening and accelerates the water turbine from a stopped state to the rated speed.

A conventional configuration of this type of speed governor control device is shown in FIG.

In Fig. 2, the speed signal N detected by the speed detector]
and the set speed signal N+4 set by the speed setter 3 are compared in the adder 2 to calculate the speed deviation signal ΔN, and this speed deviation signal ΔN is input to the PID regulator 4 to adjust the output of each element. A PID composite signal is obtained, and this PID composite signal and the limit signal from the load limiter 6 are manually input to the low value priority device 5, and the lower one is outputted as the opening command signal 0 quintillion.

When the water turbine is in a stopped state, the limit signal (PID composite signal) is output, so the output θ tree of the low value priority device 5 becomes the limit signal from the load limiter 6. Also, when the water turbine is near the rated speed, Since the limit signal is a PID composite signal, the output θ tree of the low value priority device 5 becomes a PiD composite signal from the PID adjuster 4.

The opening command signal O obtained by the low value priority device 5 in this way
* indicates the opening signal 0 detected by the position detector 10 and the adder 7
The opening deviation signal Δθ obtained thereby drives the servo motor 9 via the electrical/mechanical converter 8.
Controls the opening degree of the guide vane.

(Problem to be solved by the invention) However, since the conventional speed governor control device described above performs startup control by setting the load limiter to a single starting opening, if this is applied to a power plant with a large fluctuation head. , there is a problem that the water turbine cannot accelerate to its rated speed, or conversely, it may overspeed.

The present invention has been made in consideration of the above problems, and even when the fluctuation head is large, it prevents the water turbine from accelerating to the rated speed when starting, or from overspeeding, thereby ensuring smooth operation. The purpose of this invention is to provide a rational water turbine speed governor control device that can perform start-up control.

[Structure of the invention]

(Means and effects for solving the problem) In order to achieve the above object, the present invention provides an effective head calculation method based on a water discharge i-co water level signal, an upper dam water level signal, and a loss head signal output from the following loss head calculator. an adder that calculates
A loss head calculation unit that calculates the loss head from the effective head signal output from the adder and the guide vane opening output from the guide vane position detector, which is effective based on the effective head signal output from the adder. A starting signal generator that calculates a starting opening command signal corresponding to the head and sets it to the load limiter as a limit signal at the time of starting, and a starting signal generator that similarly calculates a load upper limit signal during normal operation and sets it to the load limiter. A load upper limit signal generator that is set as a limit signal is installed, and the opening of the guide vane of the water turbine is adjusted to an appropriate limit according to the effective head, thereby making the water turbine stable even in power plants with large fluctuations in head. This allows startup and normal operation.

(Embodiment) FIG. 1 shows an embodiment of a speed governor control device for a water turbine according to the present invention. In FIG. 1, the same elements as those in the conventional FIG. 2 are given the same reference numerals, and their explanations are omitted.

In FIG. 1, reference numeral 13 denotes a loss head calculation unit, in which the guide vane opening degree signal 0 obtained by the position detector 10 is combined with an adder 14.
The actual flow rate is calculated from the effective head signal obtained in , and the head loss at this actual flow rate is calculated.

The head loss signal obtained by the head loss calculator 13 is input to the adder 14 together with the outlet water level signal and the upper dam water level signal obtained from the water level detection tank 11.12, and is output as an effective head signal.

The effective head signal is also input to the starting signal generator 15 and the load limit signal generator 6, and a starting opening command signal and load upper limit signal suitable for the effective head are calculated and input to the load limiter 6. .

In the conventional configuration shown in Fig. 2, there is no function to calculate the starting opening command signal according to the effective head, and the output OL of the load limiter 6 is fixed at θLO as shown by the broken line in Fig. 3. Therefore, when the effective head is large, the rotational speed N of the water turbine is the third
When overspeed occurs as shown by the broken line in the figure, and the effective head is small, the rated speed is not reached as shown by the dotted line in Fig. 3.

However, in the present invention, when the effective head is large, the output OL of the load limiter 6 becomes small and overspeed is suppressed, and when the effective head is small, the output OL of the load limiter 6 is suppressed.
This prevents a situation where L becomes too large and the rated speed is not reached.

At this time, the load limiter output θゝ, guide vane opening O1, and water turbine rotation speed N are as shown by the solid line in Figure 3, and even during operation, they are not limited to a fixed opening, but are adjusted according to the effective head. Appropriate load shedding is performed.

〔Effect of the invention〕

As explained above, according to the present invention, when starting a water turbine, an appropriate starting opening according to the effective head is automatically set in the load limiter, so even in a power plant with a large variable head, when starting This prevents the rated speed from reaching the rated speed or from overspeeding, which enables smooth startup control.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of a water turbine speed governor control device according to the present invention, Fig. 2 is a block diagram showing the basic configuration of a conventional water turbine speed governor control device, and Fig. 3-7 to 7 are at startup. This is a time chart I- showing the response characteristics of . 1...Speed detector 2,7. ], 4・Adder 3
...Speed setter 4...PID regulator 5 -Low value priority device 6...Load limiter 8...Electrical/
Mechanical converter 9...Servo motor lO...Position detector 11...Upper dam water level detector 12...Water outlet water level detector 13...Loss head calculator 15...Start signal generator ]6.・Load upper limit signal generator agent Patent attorney Noriyuki Chika Yudo Ken Daishimaru

Claims (1)

[Claims] A speed detector that detects the rotational speed of the water turbine, a speed setter that outputs the rotational speed command signal of the water turbine, a position detector that detects the opening of the guide vane, and a load that outputs the opening limit signal of the guide vane. a limiter; a PID regulator that outputs a PID composite signal by performing proportional, integral, and differential calculations on the deviation between the speed signal output from the speed detector and the speed command signal output from the speed setter; A low value priority device outputs the lower of the PID composite signal output from the regulator and the limit signal output from the load limiter as an opening command signal, and an opening command output from the low value priority device. In a water turbine speed governor control device equipped with a servo mechanism that adjusts the opening degree of the guide vane according to the deviation between the signal and the opening degree signal output from the position detector, a water outlet water level signal, an upper dam water level signal, and an adder that calculates the effective head from the loss head signal output from the loss head calculator below, and the loss head from the effective head signal output from the adder and the guide vane opening degree output from the position detector. a head loss calculator for calculating, and a starting signal generator for calculating a starting opening command signal corresponding to the effective head based on the effective head signal output from the adder and setting it as a limit signal to the load limiter. A speed governor control device for a water turbine, comprising a load upper limit signal generator that calculates a load upper limit signal during normal operation and sets it as a limit signal to the load limiter.