Water diversion type cascade series hydropower station group

Abstract

The utility model provides a water diversion type cascade series hydropower station group. Each stage of hydropower station comprises a water inlet, a water diversion tunnel, a surge chamber, a branch pipe, a plant, a flow balance discharge hole, an energy dissipation facility, a tail water tunnel and a regulating reservoir. Wherein the water inlet of the first-stage hydropower station is communicated with a reservoir, and the last-stage hydropower station is connected with a downstream river channel; a flow balance discharge hole is arranged below a plant of each stage of hydropower station, the flow balance discharge hole is connected with the plant in parallel, the upstream of the flow balance discharge hole is separated from a diversion tunnel through a branch pipe, the downstream of the flow balance discharge hole is communicated with a regulating reservoir, the flow balance discharge hole is provided with a valve chamber, a discharge ball valve and a flow regulating valve are mounted in the valve chamber, and an energy dissipation facility is arranged at the downstream of the valve chamber. The water flow stably enters the adjusting tank. On the premise that work of other hydropower station units in the cascade is not affected, the flow can still be normally lowered into a downstream reservoir, and therefore it is guaranteed that power generation of upstream and downstream hydropower stations is not affected.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of hydropower station construction and hydropower station operation and maintenance, especially relates to a method for normal flow generation of water diversion type cascade series hydropower station under complex conditions, and specifically designs a water diversion type cascade series hydropower station group. BACKGROUND

[0002] The water diversion type cascade hydropower station is usually a plurality of hydropower stations connected in series by a plurality of water diversion tunnels with gentle slope in the river section with large slope and concentrated drop, which is not convenient for dam building. However, in the process of hydropower station operation and maintenance, the failure or maintenance of individual units is inevitable. When the unit fails or is under maintenance, the water diversion type cascade hydropower station will close the ball valve of the unit. Since the tail water tunnel of the upper level of the tunnel water diversion cascade hydropower station is directly connected with the water diversion tunnel of the lower level, the closure of the ball valve of the unit will result in the failure of water discharge, and thus the ball valves of the upstream and downstream hydropower station units connected with the unit also need to be closed to avoid the overflow of water and the occurrence of safety accidents. The flexibility of this kind of hydropower station group scheduling mode is poor. Once a unit fails, the upstream and downstream hydropower stations cannot generate electricity normally, resulting in a large waste of electricity and a great impact on the stability of the power grid. Therefore, in the prior art, the water diversion type cascade hydropower station lacks flexibility in the process of operation and maintenance. Once a unit fails, the upstream and downstream hydropower stations cannot generate electricity normally, which greatly reduces its actual significance and cannot be effectively applied. CONTENT OF THE UTILITY MODEL

[0003] To solve the existing technical problems, the main purpose of the utility model is to provide a water diversion type cascade series hydropower station group. This construction and scheduling method can still discharge the flow to the downstream reservoir without affecting the work of other hydropower station units in the cascade, thereby ensuring the power generation of the upstream and downstream hydropower stations is not affected, realizing the maximization of the overall benefit of the cascade hydropower station, and ensuring the safety and stability of the power grid.

[0004] In order to realize the above technical features, the purpose of the utility model is realized as follows: a water diversion type cascade series hydropower station group, which is constructed in a mountain with height difference and connects a plurality of hydropower stations through tunnels in the mountain.

[0005] Each hydropower station includes a water inlet, a water diversion tunnel, a surge chamber, a branch pipe, a powerhouse, a flow balance discharge hole, an energy dissipation facility, a tail water tunnel and a regulation pool.

[0006] The water inlet of the hydropower station at the first level is connected with the reservoir, and the water inlet of the hydropower station at the last level is connected with the downstream river.

[0007] The flow balance discharge hole is arranged below the powerhouse of each hydropower station, and the flow balance discharge hole is connected with the powerhouse in parallel. The flow balance discharge hole is branched from the water diversion tunnel through the branch pipe at the upstream, and is connected with the regulation pool at the downstream.

[0008] The flow balance discharge hole is provided with a valve chamber, a discharge ball valve and a flow regulating valve are installed in the valve chamber, and an energy dissipation facility is arranged downstream of the valve chamber to ensure that water flows smoothly into the regulating pool.

[0009] The power plant is internally provided with a unit ball valve and a unit.

[0010] Each water diversion tunnel of each stage of the hydropower station has at least one.

[0011] The regulating pool is provided with three water levels, namely, an upper limit water level, a normal storage water level and a dead water level, and the water level can be adjusted between the dead water level and the upper limit water level; the storage capacity between the normal storage water level and the dead water level is a lower regulating storage capacity, and the storage capacity between the normal storage water level and the upper limit water level is an upper regulating storage capacity.

[0012] The end of each single water diversion tunnel of each stage is connected to at least one water diversion branch tunnel, the other end of the water diversion branch tunnel is connected to the unit ball valve and the unit inside the power plant, and the unit is connected to the regulating pool through a tail water tunnel.

[0013] The valve chamber is separately arranged or shared with the power plant.

[0014] The flow balance discharge holes of adjacent water diversion tunnels are arranged at the middle part of the water diversion tunnels, and share a valve chamber and an energy dissipation facility.

[0015] The utility model has the following beneficial effects:

[0016] 1. The utility model discloses a tunnel water diversion cascade hydropower station, which is provided with a flow balance discharge hole connected to a regulating pool through a water diversion tunnel below the power plant, so that the normal flow of a unit of a certain stage of the hydropower station can be ensured when the unit fails or needs to be repaired, thereby ensuring the normal maintenance of the unit.

[0017] 2. The utility model discloses a valve chamber arranged downstream of the flow balance discharge hole, and the ball valve of the failed or repaired unit is symmetrically opened and closed during operation and maintenance, and a flow regulating valve is arranged in the valve chamber, thereby the size of the discharge flow can be well controlled.

[0018] 3. The utility model discloses an energy dissipation facility arranged downstream of the valve chamber, thereby the water flow energy can be eliminated and the water head can be weakened to prevent damage to the tail water tunnel.

[0019] 4. The utility model discloses a water diversion cascade series hydropower station group, and the excess water enters the regulating pool from the flow balance discharge hole, and an additional drainage tunnel does not need to be constructed downstream of the power plant.

[0020] 5. When a unit of a certain stage of the cascade hydropower station fails or needs to be repaired, the ball valve of the failed unit of the stage is closed, and the flow balance discharge hole ball valve is immediately opened.

[0021] 6、The scheduling method of the utility model can ensure normal water flow of the upstream and downstream cascade hydropower stations and normal power generation of the upstream and downstream cascade hydropower stations when a unit of a certain level hydropower station fails or needs to be overhauled, so that the overall power generation benefit of the cascade hydropower stations is maximized.

[0022] 7、The scheduling method of the utility model has great flexibility and adjustability, in the dry season, in order to ensure the maximum benefit of water quantity, the upstream and downstream units related to the overhauled or failed unit can be all closed, and the water quantity is stored in the reservoir; in the wet season, when the unit is overhauled or fails, the water quantity can be discharged into the downstream through the flow balance discharge hole, so as to ensure the power generation of the upstream and downstream units.

[0023] 8、The scheduling method of the utility model can ensure power generation of the upstream and downstream when the unit fails or is overhauled, so as to reduce the influence on the stability of the power grid. BRIEF DESCRIPTION OF DRAWINGS

[0024] The utility model will be further described below in combination with the drawings and examples.

[0025] Figure 1 It is a schematic diagram of a diversion cascade series hydropower station group of the utility model example.

[0026] Figure 2 It is a longitudinal section view of a certain level hydropower station in the utility model example

[0027] Figure 3 It is a plan view of a certain level hydropower station in the utility model example.

[0028] Figure 4 It is a water level change diagram of the upstream regulating pool of the accident unit in the operation and maintenance process of the utility model example.

[0029] Figure 5 It is a water level change diagram of the downstream regulating pool of the accident unit in the operation and maintenance process of the utility model example.

[0030] In the drawing: first level hydropower station 1, second level hydropower station 2, third level hydropower station 3, fourth level hydropower station 4, mountain body 5, reservoir 6, downstream river channel 7;

[0031] Diversion tunnel 101, surge chamber 102, branch pipe 103, flow balance discharge hole 104, powerhouse 105, valve chamber 106, energy dissipation facility 107, tailrace tunnel 108, regulating pool 109, water inlet 110, unit ball valve 111, unit 112, discharge ball valve 113, flow regulating valve 114, upper limit water level 115, normal storage water level 116, dead water level 117, diversion branch tunnel 118. DETAILED DESCRIPTION

[0032] The embodiments of the utility model will be further explained with reference to the drawings.

[0033] Embodiment 1:

[0034] Referring to Figures 1-5 A diversion type cascade series hydropower station group, the hydropower station group is constructed in a mountain 5 with height difference, and a plurality of hydropower stations are connected in series through a tunnel in the mountain 5; each level of hydropower station comprises a water inlet 110, a diversion tunnel 101, a surge chamber 102, a branch pipe 103, a powerhouse 105, a flow balance discharge hole 104, an energy dissipation facility 107, a tailrace tunnel 108 and a regulating pool 109; wherein the water inlet 110 of the hydropower station at the first level is connected with a reservoir 6, and the hydropower station at the last level is connected with a downstream river channel 7; the flow balance discharge hole 104 is arranged below the powerhouse 105 of each level of hydropower station, the flow balance discharge hole 104 is connected in parallel with the powerhouse 105, the flow balance discharge hole 104 is branched from the diversion tunnel 101 through the branch pipe 103 at the upstream, and is connected with the regulating pool 109 at the downstream, the flow balance discharge hole 104 is provided with a valve chamber 106, a discharge ball valve 113 and a flow regulating valve 114 are installed in the valve chamber 106, the energy dissipation facility 107 is arranged at the downstream of the valve chamber 106, so as to ensure that the water flow enters the regulating pool 109 stably. Through the design of the utility model, when a unit of the cascade hydropower station fails, the water flow can still enter the regulating pool through the flow balance discharge hole, and the regulating pool can temporarily ensure the smooth flow of the upstream and downstream by regulating the water volume. After the water flow is normal, the flow regulating valve is used to control the flow, so that the flow of the regulating pool gradually recovers to the normal water storage level.

[0035] The flow balance discharge hole 104 can be quickly started when the powerhouse unit fails to be closed, so as to reduce the storage capacity of the regulating pool to the maximum extent and save the engineering cost.

[0036] The utility model discloses a cascade hydropower station, and each level needs to be provided with a branch pipe, a flow balance discharge hole, a discharge ball valve, a flow regulating valve, an energy dissipation facility and a regulating pool of the lower level hydropower station at the rear end of the diversion tunnel. Unlike the conventional tunnel diversion cascade hydropower station, the excess water in the diversion type cascade series hydropower station group of the utility model can smoothly enter the downstream from the flow balance discharge hole, and it is not necessary to set an additional drainage tunnel at the tailrace tunnel.

[0037] Further, the powerhouse 105 is internally provided with a unit ball valve 111 and a unit 112. The unit ball valve 111 can be quickly closed when the unit fails, so as to facilitate the maintenance or position of the unit.

[0038] Further, the diversion tunnel 101 of each level of hydropower station has at least one. The multiple diversion tunnels 101 can supply water to multiple units, so as to improve the power generation efficiency.

[0039] Further, the regulating pool 109 is provided with three water levels, i.e. an upper limit water level 115, a normal water storage level 116 and a dead water level 117, and the water level can be adjusted between the dead water level 117 and the upper limit water level 115; the storage capacity between the normal water storage level 116 and the dead water level 117 is the lower regulating storage capacity, and the storage capacity between the normal water storage level 116 and the upper limit water level 115 is the upper regulating storage capacity. The three water levels ensure the subsequent normal water level regulation, thereby ensuring stable power generation.

[0040] Further, the end of the single diversion tunnel 101 of each stage is connected with at least one diversion branch tunnel 118, the other end of the diversion branch tunnel 118 is connected with the unit ball valve 111 and the unit 112 inside the powerhouse 105, and the unit 112 is connected with the regulating pool 109 through the tailrace tunnel 108. The multiple diversion branch tunnels 118 facilitate water supply for multiple different units.

[0041] Further, the valve chamber 106 is separately arranged or shared with the powerhouse 105. The above arrangement reduces the construction cost.

[0042] Further, the flow balance discharge hole 104 of the adjacent diversion tunnel 101 is arranged at the middle part of the diversion tunnel 101, and shares one valve chamber 106 and energy dissipation facility 107. The above arrangement reduces the construction cost.

[0043] Embodiment 2:

[0044] A construction method of a diversion type cascade series hydropower station group, comprising the following steps:

[0045] Step 1: A branch pipe 103 is arranged downstream of the diversion tunnel 101 of the diversion type cascade hydropower station group;

[0046] Step 2: One end of the branch pipe 103 leads to the powerhouse 105 for power generation, and the other end bypasses the powerhouse 105 to arrange a flow balance discharge hole 104 connected to the regulating pool 109;

[0047] Step 3: A valve chamber 106 is arranged at a suitable position of the flow balance discharge hole 104 in step 2, and a discharge ball valve 113 and a flow regulating valve 114 are installed in the valve chamber 106;

[0048] Step 4: An energy dissipation facility 107 is arranged downstream of the valve chamber 106 in step 3;

[0049] Step 5: A regulating pool 109 of the next stage hydropower station is arranged behind the tailrace tunnel 108 downstream of the powerhouse 105;

[0050] Step 6: The subsequent multiple stages of hydropower stations are constructed in turn until the last stage of hydropower station.

[0051] Further, the flow balance discharge hole 104 in step 2 is used for balancing the flow during unit failure or maintenance; the flow balance discharge hole 104 is used for balancing the corresponding unit of the water diversion tunnel 101, and the design flow of the water diversion tunnel is unchanged, and the tunnel diameter is unchanged;

[0052] Further, the discharge ball valve 113 in step 3 is used for controlling whether the water flow passes through the flow balance discharge hole 104 to flow downstream;

[0053] Further, the energy dissipation facility 107 in step 4 is used for eliminating the water flow energy and reducing the water head, so as to prevent the flow state of the regulating pool 109 from being disturbed and affect the water diversion power generation;

[0054] Further, the regulating pool 109 in step 5 is used for regulating the flow during the opening and closing of the upstream and downstream unit ball valves 111 for a short time, so as to ensure that the upstream is not blocked and the downstream is continuously flowing.

[0055] Embodiment 3:

[0056] A dispatching method of a water diversion type cascade series hydropower station group, comprising the following steps:

[0057] Step 1: when all units in the cascade series hydropower station group are normally working, the discharge ball valve 113 of the flow balance discharge hole 104 is kept closed, and the water flow passes through the multiple-stage hydropower station flow units for normal power generation;

[0058] Step 2: when a unit in the cascade series hydropower station group fails or needs to be maintained, the unit ball valve 111 of the failed unit of the hydropower station is closed, and at the same time, the discharge ball valve 113 of the flow balance discharge hole 104 is opened, and the flow regulating valve 114 is adjusted;

[0059] Step 3: the water flow enters the regulating pool 109 after passing through the flow balance discharge hole 104 and the energy dissipation facility 107, and then flows into the downstream cascade hydropower station; at the same time, the failed unit is started to be maintained or repaired;

[0060] Step 4: after the unit is maintained or repaired, the flow regulating valve 114 is adjusted, the discharge ball valve 113 of the flow balance discharge hole 104 is closed, and the unit ball valve of the original failed unit is opened, and the cascade hydropower station resumes normal power generation.

[0061] Embodiment 4:

[0062] According to different water inflow, a dispatching scheme is determined to ensure that the power generation capacity is maximum and the influence on the power grid is minimum, which specifically comprises:

[0063] In the wet season:

[0064] Step 1: When all the units in the cascade hydropower station are working normally, keep the discharge ball valve of the flow balance discharge hole closed, and the water flows through the multi-stage hydropower station units for normal power generation;

[0065] Step 2: When a unit in the cascade hydropower station fails or needs to be repaired, immediately open the discharge ball valve of the flow balance discharge hole after the unit ball valve of the failed unit in the hydropower station is closed;

[0066] When the unit ball valve of the first-stage hydropower station powerhouse unit is closed, the inflow of the second-stage regulating pool decreases, the water level will temporarily drop, the discharge ball valve of the flow balance discharge hole of the first-stage hydropower station is opened, the water level of the second-stage regulating pool decreases slowly and gradually rises before reaching the dead water level, the flow is adjusted through the flow regulating valve to restore the water level of the second-stage regulating pool to the normal storage level, and due to the regulating effect of the downstream second-stage regulating pool, the water levels of the third-stage and subsequent cascade hydropower station regulating pools remain unchanged;

[0067] When the unit ball valve of the second-stage hydropower station powerhouse is closed, the outflow of the second-stage regulating pool decreases, the water level will temporarily rise, the inflow of the third-stage regulating pool decreases, the water level will temporarily drop, the discharge ball valve of the flow balance discharge hole of the second-stage hydropower station is opened, the water level of the second-stage regulating pool rises slowly and gradually drops before reaching the upper limit water level, the water level of the third-stage regulating pool drops slowly and gradually rises before reaching the dead water level, the flow is adjusted through the flow regulating valve to restore the water levels of the second-stage and third-stage regulating pools to the normal storage level, and due to the regulating effect of the upstream and downstream second-stage and third-stage regulating pools, the water levels of the second-stage and above, third-stage and below cascade hydropower station regulating pools remain unchanged; the subsequent multi-stage power stations are similar, and when the unit ball valve of the last-stage hydropower station powerhouse is closed, the outflow of the last-stage regulating pool decreases, the water level will temporarily rise, the discharge ball valve of the flow balance discharge hole of the last-stage hydropower station is opened, the water level of the second-stage regulating pool rises slowly and gradually drops before reaching the upper limit water level, and the flow is adjusted through the flow regulating valve to restore the water level of the last-stage regulating pool to the normal storage level, and due to the regulating effect of the last-stage regulating pool, the water level of the upstream regulating pool remains unchanged;

[0068] Step 3: The water flows through the flow balance discharge hole and energy dissipation facilities and then normally flows into the downstream cascade hydropower station through the regulating pool, and at the same time, the associated units start to repair or maintain the failed units;

[0069] Step 4: After the unit repair or maintenance is completed, the unit ball valve of the original failed unit is opened, the cascade hydropower station resumes normal power generation, the flow is reduced through the flow regulating valve, and the discharge ball valve of the flow balance discharge hole is closed to control the water levels of the upstream and downstream regulating pools at the normal storage level.

[0070] The scheduling method can ensure normal water flow of the upstream and downstream cascade hydropower stations, ensure normal power generation of the upstream and downstream cascade hydropower stations, avoid simultaneous shutdown of the cascade series hydropower stations, not only achieve maximum overall power generation benefit of the cascade hydropower stations, but also ensure power grid stability.

[0071] Embodiment 5:

[0072] In the dry season:

[0073] Step 1: when all units in the cascade hydropower station are normally working, keep the discharge ball valve of the flow balance discharge hole closed, and the water flow normally generates electricity from the upstream through the multi-stage hydropower station water flow unit;

[0074] Step 2: when a unit in the cascade hydropower station fails or needs to be repaired, the unit ball valve of the failed unit of the cascade hydropower station is closed, the discharge ball valve of the flow balance discharge hole is immediately opened, and the flow regulating valve is adjusted, the water level of the upstream and downstream regulating pools changes temporarily and returns to the normal storage water level;

[0075] Step 3: sequentially close the unit ball valves of the upper and lower units connected in series with the unit under repair or failure, and simultaneously open the discharge ball valve of the flow balance discharge hole, control the regulating pool water level near the normal storage water level through the flow regulating valve, and report to the power grid through the prepared plan, and avoid simultaneous shutdown of the cascade series hydropower stations before starting the plan, to ensure safe and stable operation of the power grid;

[0076] Step 4: simultaneously control the flow regulating valves of the flow balance discharge holes of the cascade hydropower stations to reduce the flow, until the discharge ball valve is closed, to reduce the water discharge and keep the water in the reservoir of the first-stage hydropower station, avoid waste, and maximize the overall power generation benefit of the cascade hydropower stations;

[0077] Step 5: after the repair or failure is handled, sequentially open the unit ball valves of the units, and start normal power generation to ensure maximum power generation in the dry season.

[0078] The scheduling method can keep the water in the uppermost reservoir of the cascade hydropower station in the dry season, and maximize the power generation benefit of the cascade hydropower station; and the influence on the stability of the power grid can be reduced by reporting to the power grid through the prepared plan.

Claims

1. A diversion type cascade series hydropower station group, the hydropower station group is constructed in a mountain (5) with height difference, and a plurality of hydropower stations are connected in series through tunnels in the mountain (5); characterized in that Each level of hydropower station comprises a water inlet (110), a diversion tunnel (101), a surge chamber (102), a branch pipe (103), a powerhouse (105), a flow balance discharge hole (104), an energy dissipation facility (107), a tailrace tunnel (108) and a regulating pool (109); The water inlet (110) of the hydropower station at the first level is connected to the reservoir (6), and the hydropower station at the last level is connected to the downstream river channel (7); The flow balance discharge hole (104) is arranged below the powerhouse (105) of each level of hydropower station, the flow balance discharge hole (104) is connected in parallel with the powerhouse (105), the flow balance discharge hole (104) is branched from the diversion tunnel (101) through the branch pipe (103) at the upstream, and is connected to the regulating pool (109) at the downstream.

2. The run-of-river type cascade series hydroelectric power station group according to claim 1, characterized in that: The flow balance discharge hole (104) is provided with a valve chamber (106), a discharge ball valve (113) and a flow regulating valve (114) are installed in the valve chamber (106), an energy dissipation facility (107) is arranged at the downstream of the valve chamber (106), so as to ensure that the water flow enters the regulating pool (109) smoothly.

3. The run-of-river type of cascade series hydroelectric power station group according to claim 1, characterized in that: The powerhouse (105) is provided with a unit ball valve (111) and a unit (112) inside.

4. The run-of-river type of cascade series hydro power station group according to claim 1, characterized in that: The diversion tunnel (101) of each level of hydropower station has at least one.

5. The run-of-river type of cascade series hydro power station group according to claim 1, characterized in that: The regulating pool (109) is provided with three water levels, which are an upper limit water level (115), a normal storage water level (116) and a dead water level (117), the water level can be adjusted between the dead water level (117) and the upper limit water level (115); the storage capacity between the normal storage water level (116) and the dead water level (117) is a lower regulating storage capacity, and the storage capacity between the normal storage water level (116) and the upper limit water level (115) is an upper regulating storage capacity.

6. A run-of-river type of cascade series hydro power station group according to claim 3, characterized in that: The single diversion tunnel (101) of each level is connected to at least one diversion branch tunnel (118) at the end, the diversion branch tunnel (118) is connected to the unit ball valve (111) and the unit (112) inside the powerhouse (105) at the other end, and the unit (112) is connected to the regulating pool (109) through the tailrace tunnel (108).

7. The run-of-river type of cascade series hydro power station group according to claim 2, characterized in that: The valve chamber (106) is separately arranged or shared with the powerhouse (105).

8. A run-of-river type of cascade series hydro power station group according to claim 7, characterized in that: The flow balance discharge holes (104) of adjacent diversion tunnels (101) are arranged at the middle part of the diversion tunnels (101), and share a valve chamber (106) and an energy dissipation facility (107).

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