JPS59105974A - Governor for water turbine - Google Patents

Abstract

PURPOSE:To permit highly efficient operation and stable switching motion by a method wherein the flow amounts of a plurality of nozzles are kept in equilibrium at all times and all of the flow amounts is set into constant when the utilizing sets of the nozzles are switched. CONSTITUTION:The strokes of needle servomotors 91-94 are corresponding to the opening degrees of each needle valves and these strokes are added by an adder 21 to obtain an amount corresponding to a total flow amount and input it into the operating device 14 for a base unit 10 and objective valve opening degree setting units 51-54. When the needle valves for the first and second nozzles are fully opened at a time t4 under the load of 100%, a command SW2 is outputted from the operating device 14, signals Y1-Y4, changing the opening degrees of the needle valves for the first and second nozzles from 100% to 50% and the same valves for the third and fourth nozzles (nozzles corresponding to the objective opening degree setting units 53, 54) from 0% to 50%, are outputted, two nozzles operating condition is switched to the four nozzles operating condition under keeping the total flow amount Q in constant, and the signals Y1-Y4 are increased toward the full opening of each needle valves under keeping the flow amounts of each nozzles in the same values in the four nozzles operating zone R4.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a speed governor for a water turbine, and particularly to an electric water governor suitable for braking the rotational speed of a generator driven by a multi-pair Pelton water turbine. Regarding speed governors for cars.

[Prior art]

A Pelton turbine is used to drive a hydroelectric generator using hydraulic power with a high head, and the water generated by the high head is injected from a nozzle and hits the runner of the turbine, which causes the Pelton turbine to rotate. A multi-pair Pelton water turbine has a plurality of nozzles installed around the water wheel, and the water jet from these nozzles rotates the water wheel. On the other hand, the speed governor for this water turbine has a speed-regulating effect until the hydroelectric generator driven by the water turbine is paralleled to the power system, a speed-governing effect against frequency changes during parallel operation, and a speed-governing effect to stop the hydraulic power generator in the event of a system accident. It is intended for action. For this reason, each nozzle is equipped with a needle valve to adjust the flow rate of the water flow, so that as the generator output increases (decreases), the total flow rate of each nozzle, that is, the input to the water turbine increases (decreases). To control the opening and closing of each needle valve,
The speed governor controls the rotation speed of the water wheel. There are mechanical and electric types, but the present invention is directed to electric speed governors with good control characteristics.

By the way, in the conventional speed governor of a multi-pair Pelton water turbine, the total flow rate is changed by changing the number of needle valves by sequentially fully opening or fully closing the needle valves of multiple nozzles. He was controlling the speed of the area. However, with this method, for example, when the needle valve of the first nozzle is fully open and there is still insufficient input, the needle valve of the second nozzle is subsequently fully opened, but this corresponds to one nozzle fully open and two nozzles fully open. In the middle of the load, the input becomes unnecessarily large, and the conversion efficiency of the urine flow input to the water wheel rotary blades is not good. Furthermore, for this intermediate load, it is possible to control one nozzle to be fully open and the other to be half open, but this would result in an unbalanced flow rate from each nozzle, and efficient operation would still not be possible.

[Purpose of the invention]

An object of the present invention is to provide an electric speed governor for a water turbine that can constantly rotate the water turbine efficiently using a plurality of nozzles.

[Summary of the invention]

The present invention prevents the total flow rate of each nozzle from changing when switching the number of nozzles, and each vfL of a plurality of nozzles after switching.
This system is characterized in that it is controlled so that the flow rate is balanced, and after switching, the control is performed by increasing or decreasing the total flow rate while maintaining the balance of the flow rate of the nozzle.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 shows an embodiment of the present invention, in which there are four nozzles. In the same figure, the basic part 1o of this device
The control signal X and the opening adjustment signals Y1~ from the valve opening target setting units 51~54 provided corresponding to each nozzle.
Y4 is input to each low value selector 71-74, and the lower value is selected, and the electrical/mechanical conversion Hir (needle valve canine needle servo motor 91-94 of each nozzle via actuator solenoid 481-84) is input to each low value selector 71-74. Driven by.

Since the strokes of the needle servo motors 91 to 94 correspond to the opening degree of each needle valve, these are added by the adder 21 to obtain the amount corresponding to the total flow rate, and the basic part 1o and the valve opening target setting are performed. The information is input to the operating devices 14 of the sections 51 to 54.

Among these, an example of the configuration of the basic unit 10 is shown in FIG. This basic unit 10 limits this difference between the speed instructed by the speed regulator 2 and the actual speed of the water turbine detected by the speed detector 1 through the amplifier 3. Output as signal X. However, in general, it is preferable for speed governors to have characteristics that cause the speed (rotational speed) N to decrease at a constant rate as the valve opening degree ■ or load increases, as shown in Figure 3. , this characteristic is expressed by the following velocity droop rate:

Here, ΔN and ΔS are the changes in the rotational speed N and the stroke S of the servo motor, and N 11 g 811 is the respective value at the rated point. To give this property,
The basic part 10 is provided with a speed droop rate setting device 4, which controls the rotation speed N to decrease in response to an increase in the valve opening degree (2).

Still shown in FIG. 4 are valve opening target setting units 51-54, which are comprised of opening target setters 518-54a and rate-of-change limiters 51b-54b. Figure 5 shows the output Yto''Y of each opening target setter 51a to 54a when a load of 100 degrees is applied to the output (or flow rate) from a stopped state.
no, and the outputs Y1 to Y4 of the rate of change limiters 51b to 54b
This characteristic provides the first characteristic of the present invention. To explain the operation with reference to this figure and Fig. 1, assuming that L=]00% is given as mentioned above, first, from the flow t Q=, o to Q=Q, o is the speed adjustment region RO; corresponds to system parallel 1 operation from the start of the water turbine, and is controlled by only one nozzle (referred to as the first nozzle). When Q=Qo, a load is applied by the parallel system, and at [=1, the flow ttQ increases until the needle valve of the first nozzle is fully opened (single nozzle area Al).

In this flow rate control, the output yto of the valve opening target setter 51a corresponding to the first nozzle is 50 in the distribution range 0 in this embodiment.
H, it becomes 100% in region R1, and this is set as change rate limiter 5.
1b, the time until Yt = Ylo is reached, the opening adjustment signal Y1 is generated so that the needle servo motor can actually follow it, and the needle servo motor 91 (Fig. 1) is controlled thereby. It will be done. If the initial load value is in the middle of this single nozzle region R1, when that load is reached, the output Accordingly, X is selected and speed regulating control is performed accordingly.

This also applies to the two-nozzle and four-nozzle regions R2 and R4, which will be described later. When the load L = 100%, control by the problem adjustment signal Y+ is continued, and when the needle valve of the first nozzle is fully open at 1 = 12, the command SWI is output from the operator 14, and YIO = Y20 = 50%. is each opening target setting section 51a
, 52a, and switching from one nozzle to two nozzles is started. That is, by setting Ylo, Y2 (1 = 5 Q%, the opening adjustment signals Y+ and Y* are both 50%.
When 1=13, Yt=Y2=50 Yu. This state means that the second nozzle corresponding to the opening target setting unit 52 and the above-mentioned first nozzle are balanced at the same opening (50%), and during this period, the decrease in Yt and the increase in Y2 are almost the same. Since it is given by the slope of Q, the total flow rate Q is almost constant and does not change. When this equilibrium switching is completed at 1=13, the opening target setter output Y+or Y2O is increased to 100 degrees, and thereby the signals Yl and Y2 gradually rise while maintaining Y1=Y2, that is, the equilibrium state, and the full wave iQ increase. 1st at t=t4. When the needle valve of the second nozzle is fully opened, a command SW2 is output from the operating device 14, and this causes the first nozzle to open fully. Set the needle valve of the second nozzle to 100
% to 50% opening, 3rd. Signals Yl-Y4 that change the needle valve of the fourth nozzle (the nozzle corresponding to the opening target setting section 53, 54) from 0 to 50% opening are output as shown in the figure, and the total flow rate Q is kept constant. Then, in the 4-nozzle region R4, the signal YI~¥4 is switched to fully open each needle valve while keeping all 4 nozzles at the same flow rate. It will increase. As is clear from the above operation, according to this embodiment, in the delicate nozzle area 2° 4, the opening degree of each valve and therefore the flow meter are always balanced, so that no matter which load f
The efficiency of the water turbine is maintained well even for ilIiL, and there is no change in the total wave while the number of nozzles is being changed, so stable switching is possible. In addition, in FIG. 5, the opening adjustment signals Y1 to Y4 are shown in a simple form, but in reality, the sixth
As shown in the figure, each needle valve opening V and %V4 follow this signal Y s = Y 4 with a slight delay, so
This valve opening degree is V! The change rate limiters 51b to 54b control the signals Y1 to V4 so that they are balanced when switching the number of nozzles.
Determine the slope of ¥4.

FIG. 7 shows another embodiment of the invention.

In the embodiments shown in FIGS. 1 and 2, the sum of all the needle valve openings is determined by the adder 21, and the droop rate is determined from this by the setting device 4, but in this embodiment, the The actual output G is detected by the power detector 12, and is multiplied by the adjustment rate by the setting device 13 to determine the drooping rate, and the detected force G is used to determine the needle valve switching position on the operating device 14. Is going. Here, the adjustment rate ε is the following value when the output frequency F is plotted on the vertical axis and the output gravity G is plotted on the reference axis as shown in FIG.

However, Fo is the frequency at no load, and FN is the frequency at rated output. Since the output frequency F is proportional to the rotation speed N of the water turbine, and the output power G is the same as the load (therefore, it corresponds to the valve opening V), the regulation rate ε given by equation (2) is the droop rate explained earlier. They can be thought of as different expressions of the speed governor, and both express the same characteristics of the speed governor. If the frequency at a given output G is F, then FOF=εG1, that is, the output G is multiplied by ε to calculate the decrease in frequency Fo from the no-load state corresponding to the droop rate.
r can be determined. However, according to this embodiment, the adjustment rate is determined by the actual generator output instead of the valve opening, so the flow rate of each nozzle can be adjusted while also correcting the gap between the opening and output characteristics due to changes in the water level difference. This has the effect of enabling balanced operation.

FIG. 9 shows yet another embodiment of the present invention, which differs from FIG. 1 in that the switching positions of zero needle valves are set by one opening target setter 5a. In this embodiment, since the target opening degrees of each needle valve are the same, it is electrically difficult to match the time required to reach equilibrium when the differences in opening degrees before and after switching are unequal for each needle valve. Although this is not possible, once the switching is completed, the same effect as the embodiments of FIGS. 1 and 7 can be achieved.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, highly efficient operation is possible by always keeping the flow rates of multiple nozzles in equilibrium, and by keeping the total flow rate constant when changing the number of nozzles. This has the effect of allowing stable switching operations.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 and 4 are diagrams showing a more detailed configuration of FIG. 1, FIG. 3 is an explanatory diagram of the speed droop rate, and FIGS. FIG. 6 is an explanatory diagram of the operation of the embodiment of FIG. 1, FIG. 7 is a block diagram showing another embodiment of the present invention, FIG. 8 is an explanatory diagram of the adjustment rate, and FIG. 9 is a further diagram of the embodiment of the present invention. It is a block diagram showing an example of. DESCRIPTION OF SYMBOLS 1...Speed detector, 2...Speed regulator, 4...Speed drooping rate setter, 51-54...Valve opening target setting unit,
51-54a...Needle valve opening target setter, 51b
~54b... Rate of change limiter, 71-74... Low value selector, 81-84... Electrical/mechanical converter, 91-94
... Needle servo motor, 10... Basic part of governor, 1, . 2... Power detector, 13... Adjustment rate setting device, 14... Operating device of needle valve opening target setting section, 1
5... Auxiliary servo motor. Agent: Patent Attorney Masami Akimoto/I21 0/4 ・5. 7 no 8
ノ] 1 1 °“ Tomoe (1+ 1 1 , j −11 ←−−1−−−−−’ 72 −
8221 Beni trouble.しSW2 1 1+ 1 I L--1---m- m---", 53 -
--”--' NiyCa-2nd day

Claims (1)

[Claims] 1. Use in response to changes in the load on a water turbine in a water turbine speed governor for adjusting the rotational speed of a water turbine equipped with multiple nozzles whose flow rates can be adjusted using needle valves. When switching the number of nozzles, the above switching is performed by controlling the needle valve of each nozzle so that the total flow rate of the nozzles in use immediately before and after the switching is the same, and the flow rate of each nozzle in use immediately after the switching is balanced. , while the number of used nozzles is constant, each of the used nozzles? ti: The above needle valves are configured to be controlled so that the total flow rate changes according to the size of the load while t remains balanced! WM speed governor for water turbines with r￥ characteristics