JPH02230967A - Controlling method for water feed device - Google Patents

Abstract

PURPOSE:To secure the preset cooling water temperature and cooling water pressure when discharging dust by controlling the discharging action of foreign objects accumulated in a strainer with the operation of an integrating timer, and acceleration-operating a pump by a fixed value during this period. CONSTITUTION:When a water feed device is operated for the preset period and an integrating timer 22 or a differential pressure switch 25 is operated, an electric sand flash valve 24 starts to be opened, and part of the cooling water to an electric strainer 23 is discharged to a draft discharge channel 26 via a drain pipe 27 together with captured foreign objects. An operation signal is applied to a comparing calculator 14 to prevent decompression, and the rotating speed of a pump 19 is increased via a variable-speed driving means 15 and a motor 17 so as to increase the water feed pressure and the water feed quantity to a main shaft water sealing device 3, a water turbine bearing 4, a water turbine generator bearing 5, and a cooler 9 measured by a flow meter 11 by fixed values. When the discharging action of foreign objects for the preset period is completed, the sand flash valve 24 is closed, and the rotation of the pump 19 is returned to the ordinary rotation. The cooling water quantity can be invariably kept optimum.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a water supply device that supplies cooling water to bearings or heat exchangers of various parts of a rotating machine, such as a water wheel in a hydroelectric power plant. The present invention relates to a control method for a water supply system, in particular, a method for controlling a water supply device that can supply a predetermined amount of cooling water to each part even when the amount of water supply fluctuates, and can continue stable operation of a water turbine even when the amount of water supply does not fluctuate.

(Prior art) In hydroelectric power plants, the guide bearings or thrust bearings of generators, the guide bearings of water turbines, etc. are equipped with cooling cooler pipes installed in the oil tank of self-contained bearings of various parts, or air coolers or pressure oil of generators. To supply cooling water to various heat exchangers such as oil collection tank coolers, there are two methods: one is to take water from a penstock and supply it directly without using a pump, and the other is to supply water from a water tank via a pump. There is. In either case, an electric strainer is installed in the middle of the water supply pipe to remove foreign objects such as wood chips, leaves, and sand from the water to prevent clogging in each cooler pipe and to prevent a decrease in water supply caused by clogging. There is. When water flows in and out from the inside to the outside or from the outside to the inside of the element in the electric strainer, debris in the water is removed by being pressed against the surface of the element, or by being pierced through holes in the element.

In order to clean the strainer, the electric motor attached to the top of the strainer is first activated by the operation of the integration timer or the differential pressure switch that detects the differential pressure between the front and rear sides of the strainer. This is done by automatically starting and rotating an element inside the strainer.

Further, the element is partitioned into several chambers, and one chamber of the element is always closed by a holding plate to prevent almost no water from flowing in or out. Therefore, the dust inside one chamber of the element that is blocked is discharged by the flow generated by the pressure difference between the water pressure outside the element and the pressure in the dust exhaust line, which is normally open to the atmosphere and has no back pressure. be done.

Further, the element rotates to remove dust from each chamber inside the element.

(Problem to be Solved by the Invention) In this way, in the conventional water supply system, when removing dust from the strainer, the cleaning of the strainer element and the water passage are performed at the same time. This results in the problem of a decrease in . In order to avoid such problems, the opening degrees of various valves in the water supply line are adjusted, or orifices are inserted into the water supply line. However, this method is not effective when the flow rate and pressure fluctuations during dust removal are large, and the pressure switches or flow rate switches installed in each cooling line will operate, so these switches should only be turned on during dust removal. Must be locked with a timer. In addition, irrational design conditions are required for various bearings, etc., so that no abnormality occurs even if the cooling water volume decreases for several minutes, and a means to increase the flow rate to several times the design value is also required.

However, even with such a design, unfavorable operating conditions occur, which shortens the life of control oil, lubricating oil, etc. used in bearings and the like.

In order to solve these problems, a water supply method (for example, Japanese Patent Application Laid-Open No. 1983-1993-1) is proposed in which the discharge pressure is measured, the calculated value is increased or decreased by a certain range, and the discharge pressure is kept constant.
65591) or a water supply device control method that controls the rotation speed of the pump so that the pressure and water pressure are in a proportional relationship depending on the amount of water used, or controls the rotation speed of the pump so that the pressure is constant (for example, , Japanese Patent Publication No. 60-243
No. 391) has been proposed. However, with the former method, only the discharge pressure is measured and the increase/decrease of the pump rotation speed is digitally controlled step by step, so there is a time delay until the predetermined rotation speed is reached. For example, in a water supply system of a hydroelectric power plant, the degree of change in pressure and overflow is very small, so control by pressure detection is not a good idea. Furthermore, in the latter method, the amount of excess water always decreases when dust is removed from the strainer, and therefore it is necessary to control the rotation speed so that the pressure remains constant.

Furthermore, in either method, the rotational speed of the pump is controlled after pressure fluctuations and flow rate fluctuations occur, so it takes a considerable amount of time until stable pressure and flow rates are obtained.

The present invention has been made to solve these problems, and is designed to ensure a predetermined amount and pressure of cooling water for the water supply device when removing dust from the strainer, and to maintain the water temperature of the cooling water at times other than when removing dust. Another object of the present invention is to provide a method of controlling a water supply device that detects the temperature of the bearing and increases or decreases the rotational speed of the pump, thereby saving energy as a whole.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a water supply device comprising a pump, a variable speed drive means for driving the pump, and an electric strainer for removing foreign matter from flowing water in a water supply pipe connected to the pump. In,
The operation of discharging foreign matter accumulated in the electric strainer is controlled by the operation of an integration timer, and when the integration timer is activated, the speed command given to the variable speed drive means is amplified by a certain value to operate the pump at an increased speed. The present invention relates to a method of controlling a water supply device, characterized in that a pump is operated at a constant speed with a constant speed command when a timer is not operating.

(Function) In the control method for the water supply device configured as described above, when the actuating element is operated, the speed command given to the variable drive means is amplified by a certain value to operate the pump at an increased speed. During operation, by operating the pump at a constant speed with a constant speed command, it is possible to discharge foreign matter accumulated in the electric strainer without reducing the amount and pressure of water supplied to each bearing, etc. The water turbine continues to operate with water supply pressure and water supply amount above a certain value.

(Example) Embodiments of the present invention will be described with reference to FIGS. 1 to 8.

As shown in the first factor, the control system of the water supply device of the present invention is composed of a penstock 28 for taking in cooling water and a water storage tank 21 for storing the taken cooling water, and a motor 17 provided in the water storage tank 21. , 18, water is supplied to the bearing 4 of the water turbine 1, the green shaft water sealing device 3, the bearing 5 of the water turbine generator 2, etc. Further, the pump 19 is a regular pump, and one set of these pumps is provided for each water turbine so that the pump 20 functions as a backup pump when the regular pump 19 breaks down. Further, the regular pump 19 is operated at variable speed, and the standby pump 20 is operated at variable speed.
is configured to operate at a constant speed. Note that the cooling water after use is discharged into the water garden 13. A coarse grid-like or shelf-like screen 16 is installed at the water intake of the penstock 28.
has been installed to prevent large pieces of driftwood from taking water. However, thin driftwood, small pieces of wood, leaves, soil, etc. pass through this screen 16, so an electric strainer 23 is usually installed on the discharge side of the pump 19, 20 to remove these foreign objects from the water. and one spare each. Furthermore, this electric strainer 23 includes a discharge pipe 27 for discharging the removed foreign matter into the draft discharge channel 26.
are connected to each strainer 23, and an electric sand discharge valve 24 for controlling this discharge is connected adjacent to each strainer 23. The electric sand discharge valve 24 is opened and closed by a command signal from the integration timer 22 or a differential pressure switch 25 that detects the differential pressure across the strainer 23. The regular pump 19 is connected to a variable speed drive mechanism 15, and this pump 19 is connected to a timer 22 or a command signal from a differential pressure switch 25, or a temperature sensor 10 that detects bearing temperature and cooling water drainage temperature.
The motor 17 is driven by a variable speed drive mechanism 15 operated by a rotation speed increase/decrease command from a comparator 14 which receives a signal from the comparator 14, and is operated at a variable speed. This command to increase/decrease the rotational speed is determined by the relational curve between the cooling water discharge temperature and the cooling water supply water ffi (with the rotational speed as a parameter) as shown in FIG. The relationship curve between bearing temperature and cooling water amount (parameter is rotation speed) as shown, or the water supply pressure (discharge pressure) as shown in Figure 6.
It is calculated by comparing the input signal and the relationship curve based on the relationship curve of the amount of water picked up (discharge amount) (parameter is rotation speed).

Foreign matter in the water removed by the strainer 23 is discharged to the draft waterway 26 via the drain pipe 27. On the other hand, the filtered water passed through the strainer 23 is supplied to the water turbine bearing cooler pipe 8, the water turbine generator bearing cooler pipe 7, the main shaft water sealing device 3, the cooler pipe 9 of the oil collection tank 6, and the like. Further, the drain pipe 12 is equipped with a temperature sensor 1o for detecting the temperature of the drain water after the heat exchange is completed, or a flow meter 11 if necessary. Furthermore, the water turbine bearing 4 and the water turbine generator bearing 5 are provided with a temperature sensor 3 for detecting the bearing temperature.
0 is attached.

The operation of the control system of the water supply apparatus according to the embodiment of the present invention configured in this manner will first be explained with respect to the operation of the dust removal valve 24. As shown in FIGS. 1 and 2, the integration timer 22 Alternatively, when the differential pressure switch 25 is activated, the electric sand discharge valve 24 begins to open, and a portion of the cooling water that is flooded into the strainer 23 is discharged to the atmosphere opening part as waste water. This causes a decrease in the amount of excess water and a transition to reduced pressure occurs. In order to prevent this state from occurring, when the operation signal of the integration timer 22 or the differential pressure switch 25 is input to the comparison calculation device 14, the calculation device 14 adjusts the rotation speed of the motor 17 to increase the water supply pressure and water supply amount. Functions to increase linearly. In addition, interrelationships such as the opening degree of the sand discharge valve, the opening operation time of the dust discharge valve, the overwater pressure, the overwater flow, etc. are obtained in advance, and the calculation device 14 uses these interrelationships as a function.
By storing the amount of increase in rotation speed for each fixed time period, it is possible to supply cooling water stably with a small fluctuation range in the amount of overwater and overwater pressure. The open state of this dust exhaust valve 24 is
A separately provided timer (not shown) continues for several minutes, and when the timer is turned off, the dust exhaust valve 24 starts to close. At this time, contrary to the opening operation, the number of rotations of the motor 17 is decreased at fixed time intervals or linearly reduced in accordance with the closing time of the dust exhaust valve 24.
Stable cooling water with small fluctuations in overwater pressure and overwater amount can be supplied to predetermined areas.

Next, the steady state in which the dust exhaust valve 24 does not operate will be described with reference to FIGS. 1 and 3. Temperature sensors 10 attached to the cooling water drain pipes 12 from the bearing cooler pipe 8 of the water turbine bearing 4 and the bearing cooler pipe 7 of the water turbine generator bearing or attached to them to detect the temperature of the bearings 4 and 5 themselves. The temperature detected by the temperature sensor 30 is input to the comparison calculation device 14. If the temperature detected by at least one of these temperature sensors 30 deviates from the set water temperature or the set bearing temperature, the comparison calculation device 1
4. On the relationship curve between cooling water discharge temperature and cooling water supply amount (Figure 8) or the relationship curve between bearing temperature and cooling water supply amount (Figure 7) stored in advance in Step 4, compare the current pump rotation speed and The optimal rotation speed is selected from the rotation speeds on these curves while keeping the discharge pressure constant. Then, while the discharge pressure is constant, a command value for increasing or decreasing the pump rotation speed by the difference between the current rotation speed and the selected rotation speed is transmitted from the comparison calculation device 14 to the variable speed drive means 15.
The rotational speed of the pump 19 is increased or decreased by the variable speed drive means 15.

As a result, the amount of cooling water is increased or decreased, and the temperature of the cooling water is maintained constant, making it possible to continue stable operation of the water turbine.

Further, when the water turbine 1 is restarted from a state in which the operation of the water turbine 1 has been stopped for a certain period of time, the procedure is as follows. That is,
As a starting condition for the water turbine 1, before starting the water turbine, the pump 19 is operated to supply cooling water to each bearing such as the water turbine bearing 4 and the water turbine generator bearing 5. As a result, as shown in Figure 5, first,
The bearing, oil, etc. are cooled, and then the water turbine 1 is started and the temperature of the bearing, oil, etc. increases due to sliding friction heat, and after a certain period of time, the amount of heat generated and the amount of released heat are balanced, and the bearing temperature and cooling water temperature decrease. becomes constant. In addition, during this transient period of starting the turbine, the bearing temperature temporarily becomes higher than the stable state due to a decrease in the bearing temperature and insufficient formation of a lubricating oil film on the bearing, and as the operating time passes, the bearing temperature becomes stable. Phenomena that transition from state to state may occur. However, since this kind of phenomenon is temporary, a timer is used to lock the comparator so that it does not operate for a certain period of time after the turbine is started, and does not issue commands to increase or decrease the rotation speed. The water turbine 1 can be brought into a stable operating state. The appropriate setting time for this timer is several tens of minutes. This enables stable operation of the water turbine without unnecessarily increasing or decreasing the rotational speed of the pump (see Figure 4).

〔Effect of the invention〕

According to the present invention, the signal of the integration timer or differential pressure switch that controls the dust removal operation of the strainer is inputted to the comparison calculation device, or the cooling water drainage temperature or the bearing temperature is inputted to the comparison calculation device. Increase or decrease the rotation speed. As a result, when operating the strainer to remove dust, it is possible to maintain a stable state of various bearings, etc., without reducing the amount of excess water or the excess water pressure. In addition, during normal operation when the strainer is not operating to remove dust, the amount of cooling water can be maintained at an optimum level by increasing or decreasing the rotation speed of the pump depending on the detected temperature. As a result, the lifespan of various bearings, water sealing devices, control oils, and lubricating oils will be extended, and problems such as bearing seizure, short-term wear of sealing materials of water sealing devices, and reductions in oil pump discharge pressure and discharge amount will be promoted. This has excellent effects such as being able to avoid abnormal conditions and also making it possible to save energy as a whole.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a control system of a water supply device according to an embodiment of the present invention, FIGS. 2 to 4 are timing diagrams for explaining control characteristics of a water supply device according to an embodiment of the present invention, and FIG. 5 is a characteristic diagram showing the bearing temperature change when starting the water turbine, Figure 6 is a diagram showing the operating characteristics of the pump, Figure 7 is a characteristic diagram showing the relationship between bearing temperature and cooling water supply amount, and Figure 8 is a diagram showing the cooling water supply amount. A characteristic diagram showing the relationship between wastewater temperature and cooling water supply amount, and FIG. 9 is a timing chart showing the control characteristics of the control system of the conventional device. 1... Water turbine, 2... Water turbine generator, 3... Main shaft water sealing device, 4... Water turbine bearing, 5... Water turbine generator bearing, 6
...Oil collection tank, 7,8.9...Cooler pipe, 10...
・Temperature sensor 11...flow meter, 12...drain pipe,
13... Water garden, 14... Comparison calculation device, 15...
- Variable speed drive means, 16... Screen, 17.18
...Motor, 19.. Regular pump, 20.. Reserve pump, 21.. Water tank, 22.. Integration timer,
23...Electric strainer, 24...Electric sand discharge valve, 2
5...Differential pressure switch, 26...Draft discharge channel, 2
7... Drain pipe, 28... Penstock pipe, 29... Draft tube, 30... Temperature sensor

Claims (1)

[Claims] In a water supply device comprising a pump, a variable speed drive means for driving the pump, and a strainer for removing foreign matter from flowing water in a water supply pipe connected to the pump, an operation for discharging foreign matter accumulated in the strainer is performed. Control is performed by the operation of an integration timer, and when the integration timer is operating, the speed command given to the variable speed drive means is amplified by a certain value to operate the pump at an increased speed, and when the integration timer is not operating, the speed command is A method for controlling a water supply device, characterized in that the pump is operated at a constant speed with the constant speed.