Method for solving problem that water intake gate of hydropower station is blocked by bed load

Abstract

The invention discloses a method for solving the problem that a water intake gate of a hydropower station is blocked by bed load, a stone blocking ridge made of C30 buried stone concrete is built at the downstream of a water inlet of a water diversion open channel of the hydropower station, the water diversion open channel is divided into an upper section and a lower section, and the upstream section forms a stone accumulation pool used for temporarily storing the blocked bed load; the stone barrier has a specific size and position to ensure that the bed load is effectively intercepted and prevented from entering the water intake gate forebay. The method further comprises the step of organizing cleaning equipment to remove bed load in the stone accumulation pool after the flood peak. The method can remarkably improve the water taking efficiency and the power generation benefit of the hydropower station, has the advantages of being easy to construct, convenient to maintain, low in cost and the like, and is suitable for various hydropower stations needing to solve the bed load blocking problem.

Description

Technical Field

[0001] The invention relates to the technical field of hydropower station engineering, and specifically to a method for solving the problem that during the rainy season, a large amount of bed load (gravel) is carried by water flow into the forebay of a water diversion gate through a water intake channel of a hydropower station, resulting in blockage of a water intake gate, thereby affecting normal power generation of the hydropower station. Background Art

[0002] The Upper Mati Hydropower Station is located at the foot of the southern Himalayas in Nepal, on the Upper Mati River. The basin has a steep terrain, the surface is mainly composed of sand and gravel, and the vegetation is sparse. After the 2016 Nepal earthquake, the stability of the mountains on both sides of the basin seriously deteriorated. During the rainy season, affected by rainfall, a large amount of bedload with a diameter of about 10cm to 120cm rolled down the slope into the river. During the flood peak, the flow rate increased sharply, and a large amount of bedload entered the flow channel from the entrance of the water diversion open channel, gathered in the forebay of the water intake gate, and seriously blocked the water intake gate, resulting in the water diversion system being unable to draw water for power generation. In order to discharge the bedload accumulated in the forebay, the power station needs to frequently open the flood discharge gate, which seriously affects the power generation time and benefits, and significantly reduces the social good evaluation, which has an adverse impact on both corporate and national development. Summary of the invention

[0003] The purpose of the present invention is to intercept a large amount of gravel (professional term: bedload) carried by the water flow in the water intake channel of a hydroelectric power station during the rainy season, which enters the forebay of the water diversion gate and blocks the water intake gate. The water intake gate cannot draw water, the generator set cannot operate, and the power generation efficiency is reduced.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for solving the problem of bed load blocking a water intake gate of a hydropower station comprises the following steps:

[0006] a) A stone barrier is built at a certain distance downstream of the water inlet of the water diversion open channel of the hydropower station. The stone barrier is made of C30 buried stone concrete and has an upper top width, a lower bottom width, a height and a length to effectively intercept the bed load entering the water diversion open channel;

[0007] b) The open channel is divided into two sections by the stone barrier, and the bottom of the upstream section is designed to be flat to form a stone pool for temporarily storing the bedload intercepted by the stone barrier;

[0008] c) Determine the volume of the rock pool to ensure that the intercepted bed load can be stored during flood peaks and prevent it from entering the forebay of the water intake gate;

[0009] d) After the flood peak, cleanup equipment is organized to enter the stone pool along the preset lower pool road, and the stored bed load is removed from one side to the other to free up space in the stone pool to prepare for the storage of bed load brought in by the next flood peak;

[0010] e) Repeat step d) until the rainy season ends or perform maintenance as needed.

[0011] Furthermore, the top width of the stone barrier is 1 meter, the bottom width is 2.5 meters, the height is 1.5 meters, the length is 22.8 meters, and the construction location is 88.6 meters downstream of the water inlet of the open channel.

[0012] Furthermore, the volume of the stone pond is designed to be 3030.12 cubic meters to meet the storage needs of the intercepted bed load during each flood peak.

[0013] Furthermore, the cleaning equipment includes but is not limited to excavators, loaders, and ballast transfer vehicles, which are used to remove the bedload from the rock pool.

[0014] Beneficial effects of the present invention:

[0015] 1. Increase the income of the power station: After the stone barrier is built, the annual income of power generation can be increased by about 1,892,500 US dollars. Specifically, the duration of the impact of bed load during the rainy season is reduced, and 10 hours of time can be avoided every day when the water intake is blocked by bed load and cannot be used for power generation, and the power generation is increased; at the same time, the maintenance costs incurred by the impact and damage of bed load on the open channel and other hydraulic structures at the head during the rainy season are saved.

[0016] 2. Increase social benefits: The present invention effectively solves the problem of bed load blocking the gate, eliminates the consequence of about 45 days of inability to generate electricity during the rainy season each year, increases power generation revenue for the power station, and contributes to the economic development of Nepal. At the same time, it demonstrates the strength and international image of Chinese hydropower construction companies, wins praise from peers, and lays a solid foundation for the company to develop the hydropower market in South Asia.

[0017] Instruction Manual

[0018] Figure 1 This is a plan view (1:100) of the stone sill in the present invention, and the units of the numbers marked in the figure are cm;

[0019] Figure 2 The figure is a cross-sectional view (1:100) of the stone sill in the present invention, and the units of the numbers marked in the figure are cm;

[0020] Figure 3 It is a solid diagram of the upstream side of the stone barrier in the present invention;

[0021] Figure 4 It is a physical diagram of the downstream side of the stone barrier in the present invention;

[0022] Figure 5 This is the effect picture of the stone fence of Liuming Channel after it was built during the rainy season (I);

[0023] Figure 6This is the effect picture after the stone railing of Liuming Channel was completed during the rainy season (Part 2). DETAILED DESCRIPTION

[0024] The scheme of the present invention is described in more detail and completely below. Specific embodiments

[0026] A method for solving the problem of bed load (gravel) blocking the water intake gate of a hydropower station.

[0027] Technical solution overview:

[0028] This technical solution aims to solve the problem of blockage of the water intake gate due to a large amount of bedload (gravel) carried by the water flow into the forebay of the water diversion gate during the rainy season in the water intake channel of the hydropower station. By building a stone barrier at a suitable position downstream of the water inlet of the open water diversion channel, a stone pool is formed to effectively intercept and store bedload, prevent it from entering the forebay of the water intake gate, and ensure normal water intake and power generation of the hydropower station.

[0029] Specific technical solutions:

[0030] Design and construction of stone barriers:

[0031] Location selection: According to the actual situation of the open channel of the hydropower station, 88.6 meters downstream of the water inlet of the open channel was selected as the location for building the stone barrier.

[0032] Structural design: The stone sill (retaining wall) is made of C30 buried stone concrete, with a top width of 1 meter, a bottom width of 2.5 meters, a height of 1.5 meters, and a length of 22.8 meters. This design not only ensures the strength and stability of the stone sill, but also facilitates construction and maintenance.

[0033] Construction requirements: Ensure the construction quality and safety of the stone barrier, strictly follow the design drawings and construction specifications to ensure that the stone barrier can effectively intercept the transported material.

[0034] Stone pool design and function:

[0035] Design principle: The open channel is divided into two sections by using stone barriers. The bottom of the upstream section is designed to be flat to form a stone pool, which is used to temporarily store the bedload intercepted by the stone barriers.

[0036] Volume calculation: The volume of the stone pond is calculated based on the flow rate of the hydropower station's open channel and the amount of bed load. In this technical solution, the volume of the stone pond is designed to be 22.8 meters (width) x 1.5 meters (depth) x 88.6 meters (length) = 3030.12 cubic meters to meet the storage needs of the bed load intercepted during each flood peak.

[0037] Cleaning and maintenance: After the flood peak, immediately organize equipment to clean the bedload in the pool (the equipment enters the gravel surface intercepted in the pool along the preset lower pool road and removes the gravel from left to right in the pool), freeing up space in the stone pool to prepare for storing the bedload brought in by the next flood peak.

[0038] The invention of the stone barrier produces the following beneficial effects:

[0039] 1. Increased power station revenue: $1,892,500 / year

[0040] The specific analysis is as follows:

[0041] The duration of being affected by bed load during the rainy season is 3.5 months. After the construction of the stone barrier, 10 hours of time a day can be avoided due to blockage of the water intake by bed load and inability to draw water for power generation. The power generation is 25,000 kilowatts per hour, and the electricity price is 0.062 US dollars per kilowatt-hour. At the same time, it saves 265,000 US dollars in maintenance costs caused by the impact and damage of bed load on the open channel and other hydraulic structures at the head during the rainy season every year.

[0042] Annual profit = 3.5 months x 30 days / month x 10 hours / day x 25,000 kilowatts / hour x 0.062 US dollars / degree + 265,000 / year = 1,892,500 US dollars / year.

[0043] 2. Increase social benefits

[0044] This invention has effectively solved the problem of bed load blocking the water intake gate, eliminating the consequence of about 45 days of power outage during the rainy season each year, thereby increasing the power generation revenue for the power station, contributing to the economic development of Nepal, demonstrating the strength and international image of China's hydropower construction companies, winning praise from peers, and laying a solid foundation for the company to develop the hydropower market in South Asia.

[0045] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for solving the problem of bed load blocking the water intake gate of a hydropower station, characterized in that: The following steps are involved: a) A stone barrier is built at a certain distance downstream of the water inlet of the water diversion open channel of the hydropower station. The stone barrier is made of C30 buried stone concrete and has an upper top width, a lower bottom width, a height and a length to effectively intercept the bed load entering the water diversion open channel; b) The open channel is divided into two sections by the stone barrier, and the bottom of the upstream section is designed to be flat to form a stone pool for temporarily storing the bedload intercepted by the stone barrier; c) Determine the volume of the rock pool to ensure that the intercepted bed load can be stored during flood peaks and prevent it from entering the forebay of the water intake gate; d) After the flood peak, cleanup equipment is organized to enter the stone pool along the preset lower pool road, and the stored bed load is removed from one side to the other to free up space in the stone pool to prepare for the storage of bed load brought in by the next flood peak; e) Repeat step d) until the rainy season ends or perform maintenance as needed.

2. A method for solving the problem of bed load blocking the water intake gate of a hydropower station according to claim 1, characterized in that: The top width of the stone barrier is 1 meter, the bottom width is 2.5 meters, the height is 1.5 meters, the length is 22.8 meters, and the construction location is 88.6 meters downstream of the water inlet of the water diversion channel.

3. A method for solving the problem of bed load blocking the water intake gate of a hydropower station according to claim 1, characterized in that: The volume of the stone pool is designed to be 3030.12 cubic meters to meet the storage needs of the intercepted bed load during each flood peak.

4. A method for solving the problem of bed load blocking the water intake gate of a hydropower station according to claim 1, characterized in that: The cleaning equipment includes but is not limited to excavators, loaders, and ballast trucks, which are used to remove the bed load from the rock pool.

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