JPS58200082A - Speed controlling apparatus for water turbine - Google Patents

Abstract

PURPOSE:To obtain stable speed characteristics of a water turbine, by using the deviation signal obtained by subtracting the no-load opening from a guide vane opening signal as a new guide vane opening signal, and thereby automatically correcting the change of the no-load opening caused by the water-level difference. CONSTITUTION:When the no-load position is detected by a no-load detector 18 from the fact that the frequency has reached the rated value, a guide vane opening signal 106 is stored and set as the no-load signal. After this, a deviation signal 112 obtained by subtracting the no-load opening 112 from the guide vane opening signal 106 is supplied as a new guide vane opening signal to a speed decreasing rate controller 22. Further, since guide vanes 14 are controlled by a speed signal 116 supplied from the controller 22, stable speed characteristics of a water turbine can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speed governor for a water turbine, and more particularly to a speed governor for a water turbine suitable for correcting changes in no-load opening due to changes in the effective head of the water turbine.

A conventional speed governor of this type of water turbine has a speed regulator that sets the target speed of the water turbine, and a predetermined speed droop rate based on a guide vane opening signal from a guide vane that changes the flow rate flowing into the water turbine. a speed droop rate regulator that forms a speed signal having a characteristic, a wave number detector that forms a speed signal according to a frequency signal from a generator that generates power by the rotational motion of the water turbine, and the speed droop rate adjuster. and a control means that receives a speed signal from a frequency detector and a target speed command from a speed regulator, respectively, and controls opening and closing of the guide vane based on these.

The operation of the water speed governor constructed in this way will be explained below with reference to FIG. 2.

FIG. 2 is a characteristic diagram showing the speed drooping rate characteristic of the speed 1f + drooping rate regulator, in which the horizontal axis shows the guide vane opening degree θ, and the vertical axis shows the speed signal (rotational speed N). shown respectively.

The speed governor of this water turbine first starts the generator with no load to bring the generator to the rated speed (rated rotation speed Nm), and then synchronizes with the frequency and phase of the power grid and turns on the parallel breaker. Then, the generator is connected to the power system, and thereafter it is operated at a predetermined speed. According to such a speed governor.

Open the guide vane to start the water force and bring the generator to the rated rotation Nm [(No-load opening → is included in the kite vane opening signal, so speed regulator 1).

Therefore, it was necessary to correct the no-load opening. In other words, when it is detected from the target speed command and the speed signal corresponding to the frequency signal that the generator has reached the rated rotation speed NmK, the speed signal from the speed droop rate regulator must be zero. It means that it must be done. However, it is difficult to provide the speed droop rate regulator with the above-mentioned function of zeroing the speed signal at the rated speed. The no-load opening amount ΔNIO is added to the target speed command in advance, and the speed signal according to the frequency signal, the speed signal from the speed droop rate regulator, and the target speed command are combined to reach the rated rotation N. I try to make it reach zero when I reach it. The no-load opening degree ΔNl・ set for this speed regulator is normally set when the effective head (water level difference) between the tokei pond and the lower pond is at its lowest, and is generally fixed. It is true. Due to this method, even if the no-load opening changes due to fluctuations in the water level difference, this will not be followed, so proper speed regulating control will not be performed.

For example, when there is a certain water level difference, reference numeral L1 in FIG. Ot
it. . , 5, oh, oh, yo, 4 Since the no-load opening ΔN 111 has been corrected by the changer, the guide vane opening θ! The rated rotation speed is Nm. However, when the water level difference fluctuates and the state of the flow rate flowing into the water turbine changes, even if it is detected that the generator is at the rated rotation based on the target speed command and the speed signal from the frequency signal, the current For a friend whose guide vane opening degree is θ, the core speed f and drooping rate regulator will output a rotational deviation ΔNml corresponding to the deviation of the no-load laparotomy (0□−θt). The speed governor operates to correct this, then corrects it to the rated value, and repeats this in sequence, which has the disadvantage that speed governor control is unstable. To prevent such a phenomenon, set the no-load opening degree ΔNzo by adding 1 minute deviation ΔNl to the target speed command of the speed regulator, and then set the next speed droop rate characteristic L.
It goes without saying that it is sufficient to set it to 2.

However, as mentioned in 1, the no-load opening of the speed setting device is generally fixed, and changing the setting according to the water level difference is extremely difficult because it also depends on the characteristics of the turbine or channel. The disadvantage was that it was difficult.

The purpose of the present invention is to solve the disadvantages of the prior art described in 1.
To provide a water control speed governor that automatically corrects changes in no-load opening due to water level difference and provides stable speed characteristics.

To achieve the above object, the present invention obtains a no-load laparotomy signal from a kite vane laparotomy signal when the water tM is started and the frequency signal from the generator or a signal corresponding thereto reaches the rated value, Thereafter, the deviation signal after subtracting the no-load opening from the guide vane opening signal will be used as the kite vane opening signal, and based on this, a speed signal with a predetermined speed drooping rate characteristic will be obtained and reflected in the opening/closing control of the guide vane. I was under pressure to do so.

Embodiments of the present invention will be described below based on drawings. FIG. 1 is a block diagram showing an embodiment of a water turbine speed governor according to the present invention.

The embodiment shown in FIG. 1 includes a speed ItlilII device 1o that sets a target speed command 10G for a water turbine (not shown), and a generator (not shown) that generates electricity according to the rotational motion of the water turbine. A frequency detector 12 generates a speed control signal 104i according to the IHL number signal 102, and a target speed command 100 from the speed control A# device 10. (Capital) Speed from the wave number jetter 12 [fN number 104 and guide vane opening #t from the guide vane 14 that varies the flow rate supplied to the water turbine, signal 106
and guide vane 1 based on these.
Control means 1 that forms a manipulated variable 108 that controls the opening and closing of 4.
6 and the frequency signal 102 or nine signals 10
4, detects that this signal 102 or F1104 has reached the rated value, and outputs a holding setting command 110; and the kite vane opening signal 10.
6'1, and when there is no holding setting command 11G from the unbalanced control output b18, the Fi-difference signal 112t is set to zero, and when the holding setting command 11G is received, the kite vane opening signal 106 at that time is taken. No-load handling [114 Yr was obtained and set to hold it, and from then on, guide bay / - relative double number 10
Deviation signal 11 obtained by subtracting non-negative #open Fil14 from 6
A speed signal having a speed droop rate characteristic as shown in FIG. 2 from the deviation No. 16 112 between the no-load opening compensation circuit 20 and the no-load opening compensation circuit 2o output as a 2t-kite vane detection signal. Speed droop rate regulator 22 to obtain 116
It is composed of:

The control means 16 in the speed governor has a target speed command 1
00, speed f#, and gi numbers 104 and 116, an arithmetic unit 164 that calculates the opening operation signal 120 from the deviation signal 118 from this adder 162, and an opening degree from this arithmetic unit 164. an adder 66 for adding the operation signal 120 and the guide vane opening signal 106 to obtain a deviation signal 122;

and an electro-hydraulic converter 168 that forms a manipulated variable 108 according to the deviation signal 122 from the addition sieve 166.

In addition, the no-load opening compensation circuit 2o has a holding setting command 1.
10, the guide vane open 1t @ No. 106 is output as the output signal 114, and when the command 110 is input, the guide vane opening signal 106 at that time is held and memorized as the no-load opening. , a no-load opening corrector 202 that outputs the H [114, There is.

The operation of this embodiment configured as described above will be explained below.

A speed signal 104 is detected from the frequency signal 102 from the generator by the same wave number detector 12, and this signal 104 and the target speed command 100 from the speed regulator 10 are added and supplied to the adder 162 to obtain the deviation signal 118. This deviation signal 118 is taken into a computing unit 164, where it forms an opening degree operation signal 120 and outputs it. This opening operation signal 120
is added to the guide vane opening degree signal 106 in an adder 166 to obtain a deviation signal 122t, which is sent to the electro-hydraulic converter 16.
Supply to 8. The electro-hydraulic converter 168 obtains a manipulated variable 108 according to the deviation signal 122, operates the guide vane 14, and controls the flow Ill flowing into the water turbine.

As a result, the speed IK of the water turbine increases and the wave number from the generator also increases. Therefore, until the no-load detector 18 detects that the 1iltlL number signal 102 reaches the rated value, that is, that the opening degree of the guide vane 14 reaches the no-load position, and outputs the hold setting signal 110, there is no load. Since the opening setting device 202 outputs the output signal 114 that follows the guide vane signal 106, the deviation signal 112 from the adder 204 becomes zero. However, the no-load detector 18 detects the no-load position at T7.
Detected when the 8 wave number reached the rated value'
At this time, the guide vane opening signal 106 at this time is stored and set as the no-load opening, and from then on, the no-load opening [1
12 is subtracted from the guide vane opening signal 106, and the deviation signal 112 is supplied to the speed droop rate [setting 22] as a new guide vane opening signal. Then, the speed signal 116 from the regulator 22 causes the guide vane 1 to
4.

Even if the water level difference fluctuates in this way, the no-load opening is always automatically set after the water type is started, and after the setting, the opening and closing of the guide par 714 is controlled to reflect this no-load opening. It is something.

The no-load opening detection 61B is configured to output the holding setting signal 110 under the conditions that the parallel breaker is open and the water turbine rotation speed has reached the rated value.

As described above, according to the present invention, operation can be performed regardless of changes in the no-load opening due to fluctuations in the effective head, so the accuracy of the speed regulating function is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a water turbine speed governor according to the present invention, and FIG. 2 is a characteristic diagram showing speed droop rate characteristics. 10... Speed regulator, 12... Frequency detector, 14
...Guide par/, 16...Control means, 18...
No-load detector, 20... No-load opening compensation circuit, 22.
. . . Drooping rate adjuster for speed, 202 . . . Non-negative opening degree corrector, 204 . . . Subtractor.

Claims (1)

[Claims] 1. Speed #Lllili to set the target speed command of the water turbine
llI generator, a same wave number detector that forms a speed signal according to a frequency signal from a generator that generates electricity by the rotational motion of the water turbine, and a kite vane opening from a variable guide vane that flows into the water turbine. a speed droop rate regulator that forms a speed signal having a predetermined speed droop rate characteristic based on a speed signal, and a speed signal from the wave number detector and the speed droop rate regulator; In a water turbine speed governor comprising a control means for taking in a target speed command and controlling the opening and closing of the kite vane based on these, the wave number signal or a signal 7 corresponding thereto is taken in, and this signal is a no-load detector that detects that the kite vane has reached its rated value and outputs a holding setting command; Obtain the no-load interval from the speed signal and set mt to be maintained during this no-load interval, and then subtract the no-load opening from the guide vane opening signal and use the nine deviation signal as the guide vane opening signal under the speed fIL image. 1. A speed governor for a water turbine, comprising: no-load opening compensating means for supplying a rate regulator.