JPS6183486A - Method of operating multistage hydraulic machinery - Google Patents

Abstract

PURPOSE:To enable safe and rapid stop of operation, by a method wherein, when a main machine, being in course of running of a water turbine, is brought into a stop, an inlet valve and a minimum pressure stage moving guide vane are closed and controlled, the guide vane is held at a low opening, the occurrence of water hammer phenomenon is controlled to a minimum. CONSTITUTION:In case an operating condition is controlled when a trouble happens or usual operation is brought into a stop, an operation control instruction for stop of a main machine is sent to a controller, not shown, for an inlet valve 6 and a minimum pressure stage moving guide vane 10 to start each closing control. In which case, the closing motion speed of the guide vane 10 is set to a value about 4-5 times as high as that of the inlet valve 6. In the closing motion, the guide vane 10 stops the closing motion when the opening is decreased to a given low value, and holds the opening as it is, but the inlet valve 6 constitutes a closing motion until the valve is fully closed. This enables a fluctuation in a water pressure due to water hammer phenomenon occasioned by a decrease in a fluctuation in a flow rate to be controlled to such a low value as possibly, enables a main machine to be safely and rapidly brought to a stop, and permits prevention of damage of devices.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention provides a multi-stage hydraulic machine that has a runner installed in each stage and a flow path in which each stage is connected by a return passage. The present invention relates to an operation control method for a multi-stage hydraulic machine that can safely and quickly stop the hydraulic machine.

(Technical background of the invention and its problems) In general, the operation of hydraulic machines such as water turbines and pump turbines is controlled by adjusting the opening degree of guide vanes arranged in a circular cascade around the outer periphery of the runner, and passing through the launch. Therefore, if the guide vane 171 degrees is suddenly changed, the flow rate will also change suddenly, so water hammer phenomenon and nurging due to changes in the flow ω will not occur in the waterway connected to the hydraulic machine. If the water pressure changes are abnormally large, there is a risk that the hydraulic machinery will be damaged or destroyed.

By the way, in a multi-stage hydraulic machine that has a flow path configuration that includes a plurality of stages and communicates between them through a return passage, the opening degree of the water port can be adjusted in order to simplify the structure and its operation control as much as possible. The movable side vanes may be arranged only around the outer periphery of the lowest pressure stage runner.

In this way, in a multi-stage hydraulic machine with a complex flow path shape in which the flow paths of each stage are connected by return passages, when the main engine is stopped, it is possible to safely and reliably stop the hydraulic machine without putting the machine in a dangerous state. A guide vane control method that can control the operation is required, but until now there has been no suitable operation control method, partly because there are many technologically unexplored fields in multistage hydraulic machines themselves.

Note that an inlet valve is usually installed as a gate valve at the inlet of a flow path of a hydraulic machine, but since the purpose of this artificial valve is to shut off the flow path, the opening and closing operations are relatively slow. If an attempt is made to control the operation I11 of the multi-stage hydraulic machine only by the inlet valve, the stop time will be long, and the equipment will be left in a severe transient state for a long period of time, which is undesirable.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and is an operational control for a multi-stage hydraulic machine that can suppress the water hammer phenomenon caused by changes in flow rate during the operation of the multi-stage hydraulic machine, and can quickly stop the main engine. The purpose is to provide a method.

[Summary of the invention]

In order to achieve the above object, the present invention includes an inlet valve at the inlet of the high pressure stage, a lowest pressure stage movable guide vane on the outer periphery of the runner of the lowest pressure stage, and a return passage between each stage. In a multi-stage hydraulic machine connected by also rapidly closes the lowest pressure stage movable guide vane, and when the lowest pressure stage movable guide vane closes to a predetermined degree, its opening operation is stopped, and the inlet valve is then opened fully. It is characterized by bringing about the state.

[Embodiments of the Invention] - Next, embodiments of the present invention will be described using a 2I32 pump-turbine shown in FIG. 2 as an example.

In Fig. 2, the high-pressure stage section of a multi-stage hydraulic machine consists of a high-pressure stage runner 2 fixed to the main shaft 1, a high-pressure stage casing 3 that houses the runner, and a circular blade row arranged inside the high-pressure stage casing 3. A hydraulic iron pipe 7 is connected to the inlet of a spiral casing 5 arranged around the high-pressure stepped casing 3 through an inlet valve 6. - Also, the lowest pressure stage section includes a lowest pressure stage runner 8 fixed to the main shaft 1, a lowest pressure stage casing 9 that accommodates the lowest pressure stage runner, and a circular blade-shaped lowest stage runner disposed within the lowest pressure stage casing. It consists of a pressure step movable guide vane 10.

The lowest pressure stage casing 9 and the high pressure stage casing 30 are connected by a return passage 11, and the lower end of the lowest pressure stage casing 9 is connected to the discharge channel (
(not shown).

In a multi-stage hydraulic machine with such a configuration, when operating a water turbine, water flowing from the penstock 7 into the high-pressure stage casing 3 via the inlet valve 6 and the volute casing 5 flows through the high-pressure stage fixed guide vane 4J5 and the high-pressure stage fixed guide vane 4J5. After passing through the high-pressure stage runner 2 and applying rotational force to the main shaft 1, the wire passes through the return passage 11 and is introduced into the lowest-pressure stage, where it is introduced into the lowest-pressure stage movable guide vane 1.
0. After flowing through the lowest pressure stage runner 8 and applying rotational force to the main shaft 1 again, it is discharged through the suction pipe 12 into the discharge channel.

On the other hand, during pump operation, water pumped from the lower pond by the lowest pressure stage runner 8 and the high pressure stage runner 2 passes through the reverse route to the water turbine operation described above, and is sent to the upper reservoir via the penstock 7.

Next, in the two-stage pump turbine configured as described above,
An operation control method when an accident such as water turbine load cutoff or pump input cutoff occurs during water turbine operation, or when the main operation is stopped will be explained with reference to FIG.

When controlling the operating state in the event of an accident such as a water turbine load IJX disconnection or pump input cutoff, or during a normal operation stop, first, an operation control command for stopping the main engine is sent to the inlet valve 6 and the lowest pressure stage movable guide vane 10. to both controllers (not shown) to start their respective closing controls. In this case, as shown in FIG. When the movable guide vane 10 reaches a predetermined clearance during the closing operation, the movable guide vane 10 stops the closing operation and maintains the same opening degree, but the inlet valve 6 continues the closing operation until it is fully opened.

In this way, in the present invention, the operation command for stopping the main engine is simultaneously transmitted to the inlet valve 6 and the lowest pressure stage movable guide vane 10, and both are controlled to close at the same time. The flow rate 1i at the inlet valve 6 is reduced in two places, and the water pressure fluctuation caused by the movement of the movable guide vane 1o in the lowest pressure stage part, which closes quickly, is reduced by the flow 1i! at the inlet valve 6. f 1li(I
It can be held down by III.

In addition, in the case of water turbine operation, the lowest pressure stage movable guide vane 1
Due to the closing operation of 0, the water pressure starts to rise upstream of this guide vane, but at that time, the lowest pressure stage movable guide vane 10 finishes the closing operation at a predetermined booth degree, so the water pressure fluctuation is reduced to the lowest pressure. The stepped movable guide vane can be held down smaller than when it is fully opened. The above-mentioned predetermined booth size is based on the actual situation, taking into consideration factors such as the opening ratio of the movable guide vane of the lowest pressure stage, the time since the start of the closing control command, the water pressure value of the penstock or spillway, or changes in the main engine rotation speed. You can choose the optimal booth size according to your needs.

As described above, in the present invention, the flow rate is reduced by simultaneously closing the inlet valve and the lowest pressure stage movable guide vane, and the flow rate fluctuation is reduced by holding the lowest pressure stage movable guide vane at a predetermined clearance. As a result, water pressure fluctuations due to the water hammer phenomenon can be kept to a minimum, and severe operating conditions of the main engine can be quickly brought to an end, thereby preventing damage or destruction of the basin.

In the above explanation, the present invention was applied to a two-stage hydraulic machine, but the present solidification is not limited to this, and the same applies to multi-stage hydraulic machines with three or more stages. Of course.

〔Effect of the invention〕

As described above, according to the present invention, when an accident occurs during operation of a multistage hydraulic machine or when the operation of the main engine is stopped, the operating state can be controlled safely and quickly.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing operating characteristics for explaining an embodiment of the method of the present invention, and FIG. 2 is a schematic vertical sectional view showing an example of the configuration of a two-stage pump water turbine as a multi-stage hydraulic machine to which the present invention is applied. . 1... Main shaft, 2... High pressure step runner, 3... High pressure step casing, 4... High pressure step fixed guide vane,
5... Swirl casing, 6... Inlet valve, 7... Water J:r: SX pipe, 8... Lowest pressure stage runner, 9...
Lowest pressure stage casing, 10: lowest pressure stage movable guide vane, 11: return passage, 12: suction pipe. eggplant f diagram

Claims (1)

[Claims] During water turbine operation, a multi-stage hydraulic machine is equipped with an inlet valve at the inlet of the high-pressure stage, a movable guide vane at the lowest-pressure stage on the outer periphery of the runner of the lowest-pressure stage, and each stage is connected by a return passage. When stopping the main engine, the operation control command is transmitted to both the inlet valve and the lowest pressure stage movable guide vane to close them both, and the lowest pressure stage movable guide vane is closed more rapidly than the inlet valve. and when this lowest pressure stage movable guide vane closes to a predetermined booth degree, its closing operation is stopped, and the inlet valve is thereafter continued to be closed to reach a fully closed state. Machine operation control method.