JPH0152590B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a multi-stage hydraulic machine, in particular, a multi-stage hydraulic machine having multiple stages of runner blades on the same axis, and connecting the outlet of each runner blade to the inlet side of the runner blade of the next stage. The present invention relates to a multi-stage pump and a pump-turbine configured to combine the lifts borne by runner blades to achieve a high overall water head.

In this way, as an example of a multi-stage pump and a multi-stage pump turbine developed for the purpose of obtaining high water head, the first
The figure shows the general structure of a two-stage pump turbine. In this figure, 1 is the upper pond, 2 is the penstock, 3 is the inlet valve, 4 is the two-stage pump turbine, 5 is the draft tube, 6 is the lower pond, 7 is the first filling pump, 8 is the upper runner, 9 is the lower runner, 10 is the upper guide vane, 1
1 is a lower guide vane, 12 is a main shaft, and 13 is a return guide.

However, when operating this two-stage pump turbine,
In power plants where there is no water flowing into the upper reservoir 1, when the pump turbine is first put into operation, or when recharging after water is drained, the water in the lower reservoir 6 is first raised to the upper reservoir 1 and then filled. It is necessary to keep it. The internal water level of penstock 2 at the start of this water filling is the same as the water level of lower pond 6,
It is located only _Hs above the center of the lower guide vane 11, and the static head difference (upper pond 1 water surface - lower pond 6 water surface) is 0. Note that H _p indicates the rated head of this two-stage pump turbine.

Figure 2 shows the relationship between the water head and efficiency of a two-stage pump turbine. The horizontal axis shows H (static head) and the vertical axis shows η (efficiency). H _x indicates a specific static head. There is. Curve A in this figure shows the two-stage overall efficiency at a certain guide vane opening, and the pumping efficiency when the static head is 0 is much worse than the pumping efficiency L when the rated head is H _p . In order to deal with this, a special pump called the initial filling pump 7 is installed, and before the start of full-scale water pumping using this two-stage pump turbine, the penstock 2 and upper reservoir 1 are filled with water, and the full-scale The water head at the start of pumping is set to be close to the rated head H _p .
For this reason, the initial filling pump needs to be a high-head pump that is sufficient to reach approximately the rated water head H _p .
Moreover, if the capacity of this initial filling pump is small, the filling time will be extremely long (for example, several months).
If this were to occur every time water is drained from the penstock, the availability of the machinery would be extremely reduced and the overall economic efficiency of the plant would be impaired. That is, the initial water filling pump requires a predetermined capacity, and therefore it is necessary to provide an expensive dedicated pump solely for water filling.

The purpose of the present invention is to eliminate such problems, shorten the number of days required for water filling, and improve plant availability. This is a purely pumped water plant that must be filled with water by pumping water, and has multiple stages of runner blades on the same axis, with the outlet of each runner blade connected to the inlet side of the runner blade of the next stage.
By combining the lifts borne by the runner blades of each stage,
In a multistage pump and a multistage pump water turbine configured to achieve a high total head, a specific number of stages counting from the highest stage and at least a stage immediately below the specific number of stages have guide vanes. A water supply line is provided that can supply water directly from the lower pond side to the runner chambers of the lowest pressure stages among the tiers and at least the specific number of tiers, bypassing the runner chambers of the lower pressure stages, and Among the stepped sections, those with guide vanes are opened to a predetermined value, and after fully closing the guide vanes of the stepped section immediately below the specific stepped section, water is pumped through the water supply line to a partial head that is significantly lower than the total head. The first feature is that the upper pond or the pipes connected to the upper pond are filled with water for the first time. This is a purely pumped water plant that must be filled with water by pumping water, and has multiple stages of runner blades on the same axis.The outlet of each runner blade is connected to the inlet side of the runner blade of the next stage. In a method for operating a multi-stage pump and a multi-stage pump-turbine configured to combine the lifts borne by the blades to achieve a high total head, the runner of a part of the stepped portions of the plurality of runner blades of the multi-stage pump or pump-turbine. Only the blades are used, the runner blades in the other stages are excluded from use, and the pumping operation is performed at a partial head that is much lower than the rated capacity, and the above-mentioned upper pond or the pipeline connected to the above-mentioned upper pond is initially filled with water. This is the second feature.

That is, the present invention achieves the objective by excluding the use of some runner blades. Specifically,
It is possible to operate with a partial head significantly lower than the rated capacity by making use of only the runner blades in some stages of the multiple runner blades of a multi-stage pump or pump-turbine, while leaving the runner blades in other stages out of use. By using partial head operation at the time of initial filling, the rated head of the initial filling pump can be significantly lowered, or the initial filling pump can be eliminated, so the cost required for the initial filling pump can be significantly reduced. Furthermore, since the main engine is used, it becomes possible to fill water at a considerably large flow rate, which shortens the number of days required for water filling and improves the availability of the plant.

Examples will be described below.

FIG. 3 is a schematic explanatory diagram of an embodiment in which the present invention is applied to a two-stage pump water turbine, and the same parts as in FIG. 1 are given the same reference numerals. This two-stage pump-turbine is different from the conventional two-stage pump-turbine shown in FIG. and draft tube 5
A bypass pipe 15 having a stop valve 14 is provided connecting the two.

When operating this two-stage pump turbine, first, the valves 16 and 17 provided before and after the initial filling pump 7 are fully opened to operate the initial filling pump 7, and the penstock 2 and upper pond 1 are operated. Fill with water. The water filling at this time is much lower than the rated static head difference in curve B, which shows the efficiency at the same guide vane opening when only one of the two stages is used in Figure 2, but the efficiency of the upper stage runner is extremely low. This is done until the static head H _p reaches point N where it does not decrease. After filling with water is completed, valves 16 and 17 are fully closed to prevent backflow of water.

Next, since it is necessary to start idling both runners after pushing down the water surface, the upper stage guide vane 10 and the lower stage guide vane 11 are fully closed, and the stop valve 14 is fully closed.
is fully opened, compressed air is introduced into the upper runner chamber 8 and the lower runner chamber 9, each runner is exposed in the air, and the water surface is pushed down to planes C and D in Fig. 3.

Next, the upper runner 8 and lower runner 9 are simultaneously started in the direction of the pump by a starting motor directly connected to the main shaft 12, and after reaching the rated speed, the traction motor is energized and then connected to the power grid and the traction motor is started. to move to.

Stop valve 1 after pumping start conditions are established.
4 is opened, and the upper guide vanes 10 are gradually opened to pump water through the bypass pipe 15 and the return guide 13. Pumping operation continues while adjusting the guide vane to an appropriate opening degree that matches the static head difference at that time, and when the upper runner is filled with water to a predetermined static head difference H _q , the 9 chambers of the lower runner are evacuated, and the lower runner is gradually The guide vane 11 is opened, and then the stop valve 14 is closed, and water pumping by both runners is started via the original route of the draft tube 5, lower runner 9, return guide 13, and upper runner 8. Thereafter, the opening degrees of the upper guide vanes 10 and the lower guide vanes 11 are adjusted in accordance with the momentary static head difference.

That is, as shown in Figure 2, this is clear from a comparison between curve B, which shows the efficiency at the same guide vane opening when only one of the two stages is used, and curve A, which shows the overall efficiency of the two stages at a certain guide vane opening. As shown, the former is higher than the latter where the static head difference is low, so in this embodiment, while the static head difference is low, the lower runner 9 is kept in a waiting state while pressing down on the water surface, and the upper runner 8 alone is used to pump water. When the static head difference becomes sufficiently high, the effective number of stages can be selected during this water filling process to make the most of both runners, allowing for maximum efficiency operation.

In this way, high-efficiency operation is possible without the use of high-head pumps, making it possible to shorten the number of days required for water filling and improve plant availability.

In addition, since it became possible to use an extremely low-capacity pump as the initial filling pump, it became possible to reduce the price, but a comparison between curve B and curve A in Figure 2 As is clearer,
Since the efficiency in the case of zero static head is significantly higher in the former case, it is also possible to omit the initial filling pump. Being able to omit the initial water filling pump means that
There is also a significant economic effect as there is no need to provide an expensive pump exclusively for filling water.

In addition, in a plant where a plurality of pumps or pump-turbines are arranged by branching penstocks, the intended purpose can be achieved by providing only one multi-stage pump-turbine of the present invention.

As described above, the multistage hydraulic machine and its operating method of the present invention can shorten the number of days required for water filling and improve plant availability, and have great industrial effects. .

[Brief explanation of drawings]

Fig. 1 is a schematic structural explanatory diagram of a two-stage pump-turbine, which is an example of a conventional multi-stage hydraulic machine, and Fig. 2 shows the efficiency of the conventional two-stage pump-turbine, which is an example of a multi-stage hydraulic machine, and the present invention. The diagram to explain, Figure 3, is
1 is a schematic structural explanatory diagram of a two-stage pump water turbine which is an embodiment of the multi-stage hydraulic machine of the present invention. 1... Upper pond, 2... Penstock, 3... Inlet valve,
4...Two-stage pump turbine, 5...Draft tube, 6...Lower pond, 7...Initial filling pump, 8...Upper runner, 8a...Upper runner blade, 9...
Lower runner, 9a...lower runner blade, 10
...Upper guide vane, 11...Lower guide vane, 12
... Main shaft, 13 ... Return guide, 14 ... Stop valve, 15 ... Bypass pipe.

Claims (1)

[Scope of Claims] 1. A pure pumping type plant that has no or little natural inflow of water into the upper reservoir, which must be filled with water by pumping water from the lower reservoir side, and has multiple stages of coaxial runner blades. In a multi-stage pump and a multi-stage pump-turbine, the outlet of each runner blade is connected to the inlet side of the runner blade of the next stage, and the head borne by the runner blades of each stage is combined to achieve a high overall head. , a specific number of steps counting from the highest step, at least another step in which a step immediately below the specific number of steps includes a guide vane, and at least a lowest pressure step among the specific number of steps. A water supply line is provided that allows water to be supplied directly from the lower pond side, bypassing the runner room, and among the specified number of steps, those with guide vanes open to a predetermined value to connect the steps immediately below the specified number of steps. After completely closing the guide vanes of the section, pumping operation with a partial lift much lower than the total pumping head is performed via the water supply line, and the above-mentioned upper pond or the conduit connected to the above-mentioned upper pond is initially filled with water. A multi-stage hydraulic machine characterized by: 2. The multi-stage hydraulic machine according to claim 1, wherein water around the runners is removed from the stepped portions other than the specific stepped portion to put them into idle mode. 3. A pure pumping type plant where there is no or little natural water flowing into the upper pond, which must be filled with water pumped from the downstream side, and has multiple stages of runner blades on the same axis, each runner blade In the method of operating a multi-stage pump and a multi-stage pump-turbine configured to connect the output of the runner blade to the inlet side of the runner blade of the next stage and combine the head borne by the runner blades of each stage to achieve a high overall head, Among the multiple runner blades of a multistage pump or pump-turbine, only the runner blades in some stages are utilized, while the runner blades in other stages are excluded from use, and pumping operation is performed with a partial head significantly lower than the rated capacity. A method for operating a multi-stage hydraulic machine, comprising initially filling the upper pond or a conduit connected to the upper pond.