SI24884A - Drain outlet for controlled and spatially limited converting of water potential - Google Patents

Abstract

The subject of the invention is a circulation release for a controlled and spatial limited conversion of the water potential for the safe and stable operation of high-pressure hydroelectric power plants with an inlet pipeline and solves the technical problems that arise in the sudden shutdown of the hydroelectric power plant due to network failure or other causes for sudden shutdown. Technical problems arising from the rapid shutdown of the turbine are: load bearing and bending propeller shafts in the escape, pressure drop in the inlet pipeline and providing a biological minimum of the flow of the river. The object of the invention solves technical problems with a comprehensive solution that includes the synchronization of the discharge valve with the guide blades of the turbine. The drain (1) connects the water turbine (10) to the spiral housing and the valve (2), the opening and closing (2) being carried out via the actuator of the valve (3) which overlaps the oil servomotor (11) and the water servomotor (12). The water servomotor (12) forces the valve to open. The oil servo motor (11) keeps the valve 2 in the closed position. In the event of a drop in pressure in the oil-powered servomotor (11), due to power failure or damage to the hydraulic aggregate, the water servomotor (12) safely opens the valve (2). When the water turbine is stopped (10), the synchronization of the valve with the guide blades of the turbine (4) through the actuator of the valve (3) ensures the opening of the valve (2), so that the total flow of water through the water turbine (10) and the valve closing the guide blades of the turbine does not change. After the stop of the water turbine (10), the valve (2) is slowly closed so that the co-pressure of the pressure in the pipeline is small or the circulation of the outlet for a controlled and spatially limited conversion of the water potential into a continuous operation is passed. The chamber (8) converts kinetic energy into potential energy. Energy conversion occurs in a closed, restricted and controlled space filled with water.

Description

Water turbines; rapid turbine shutdown; hydraulic stroke; cavitation; lowering of the river bed; synchronization of valve with water vane; dissipation chamber; aperture.

View the problem

An extremely rapid shutdown of the water turbine results in a partial escape of the turbine and a high pressure water stroke, which can damage individual parts of the water turbine and inlet pipeline. One of the modern safety solutions is that the water is diverted past the water turbine, but the sudden discharge of the water stream due to the large amount of released energy endangers the environment, potential water activities and people, and above all can damage or leak banks and uncontrollably change the shape of the river bed. Uncontrolled discharge or sudden shutdown of water flow causes loads, damages, vibrations and noise in the turbine plant. Likewise, the free (in) operation of a water turbine that adapts to the consumption of electricity threatens the river ecosystem and the biological minimum in the river itself.

The state of the art

Water turbines are always designed to withstand the loads resulting from rapid shutdowns. For this purpose, the turbines and other auxiliary systems are adequately (re) dimensioned and also include a number of safety elements such as water level, high pressure piping, air valves and the like. Circulating discharge for controlled and space-limited conversion of water potential is a modern safety solution that replaces many other systems, while greatly expanding the usability and acceptability of a water turbine in the natural environment. Several related solutions are known to include the individual elements of the proposed bypass system; But no known solution solves the problem of energy dissipation so comprehensive, efficient, compact, controlled and affordable. The advantage of the proposed circulating discharge lies in the set and proper connection of the various components into one optimum system that allows for very flexible operation, is easy to maintain and is investment-friendly and easy to build.

Description of the new solution

The subject of the invention is a bypass discharge for controlled and spatially limited conversion of water potential for safe and stable operation of high pressure hydroelectric power plants with inlet pipeline and solves the technical problems arising from the sudden shutdown of the hydroelectric power plant due to network failure or other causes of sudden shutdown.

The main technical problems encountered in the rapid shutdown of the turbine are:

bearing loads and slippage of the propeller blades as a result of the increase of the turbine speed or the escape of the turbine a pressure stroke which spreads up and down the pipeline and can damage the pipeline as a result of rapid stoppage of water flow when the guide blades close

- ensuring a biological minimum of river flow due to interruption of water flow into the river (reduction of water level / flow).

The subject of the invention solves the technical problems with a comprehensive solution, which includes synchronization of the discharge valve with the turbine guide blades, more functional operation and conversion of the water potential in a controlled and space-limited manner with less vibration and less noise.

The technical solution of the invention lies in the placement of the selected components and the connections between them, so that the system is easily adaptable to different inlet parameters of pressure and flow, while at the same time the construction is compact and easy to build and maintain. The object of the invention may be used for a short time in the event of a sudden shutdown of a hydroelectric power station or for a long time as an adjustment / provision of the necessary river flow.

A high pressure turbine discharge for controlled and space-limited conversion of water potential is a hydroelectric safety system that replaces conventional and established safety components, systems and measures (water level, pressure pipeline, turbine escape design, etc.). It works by redirecting the flow of water to the circulation outlet for a controlled and spatially limited conversion of water potential through a rapid shutdown of the water turbine 10 via a special valve 2. The flow of water coming through this discharge conserves all the kinetic energy, which is then converted into potential energy in a confined space (dissipation chamber 8). A high pressure turbine discharge for controlled kinetic energy conversion in a confined space is used to mitigate transient events (water shock), in sudden / instantaneous shutdown of the turbine.

According to the invention, the problems with the right choice of components are completely solved. Circumferential discharge for controlled and space-limited conversion of water potential consists of several components, which are dimensionally adjusted according to the inlet parameters (drop, flow, required start and stop speed), and according to the turbine layout (horizontal, vertical).

The first component is the inlet 1 or inlet pipeline connecting the water turbine 10 at the spiral housing site and valve 2. Valve 2 is dimensioned and designed so as not to cause losses during the operation of the water turbine 10, and thus to provide a controlled discharge during operation and space-limited conversion of the water potential from the water turbine 10 to the valve 2 as short as possible (compact design).

Valve 2 ensures that:

the flow of water passing through the water turbine 10 from zero to the total flow is taken over at any time and in an instant,

- to reduce the impact of increased pressure on the sudden shutdown of a hydropower plant, to ensure sealing during non-operation,

- a constant flow during operation is maintained to ensure long-term operation without cavitation damage and to ensure changes in loads and flow during operation.

Valve 2 is designed and constructed to withstand cavitation and erosion, and its operation is unconditional.

The valve 2 is opened and closed via a valve actuator 3, which comprises an oil servomotor 11 and a water servomotor 12. The water servomotor 12 is directly connected to the water pressure in the pipeline before the water turbine 10 and forces the valve to open. The oil servomotor 11 holds the valve 2 in the closed position and acts in the opposite direction of the water servomotor 12. In the event of a fall in oil pressure in the oil servomotor 11, due to a power failure or failure of the hydraulic unit, the water servomotor 12 opens the valve 2 safely.

Synchronization of the valve with the guide blades of the turbine 4 is essential for the proper operation of the invention. When shutting down the water turbine 10, synchronization of the valve with the guide blades of the turbine 4 via the actuator of valve 3 ensures that valve 2 is opened so that the total flow of water through the water turbine 10 and valve 2 does not change during closing of the guide blades of the turbine. After the shutdown of the water turbine 10 is closed, valve 2 is slowly closed so that the pressure changes in the pipeline are small or the circulation discharge is passed for controlled and spatially limited conversion of the water potential into continuous operation. When starting the water turbine 10, valve 2 closes synchronously by opening the guide blades of the water turbine 10 and the process is reversed.

Due to the high pressures before valve 2, the velocities in the valve are extremely high, causing local pressure drops and associated cavitation. By adding air with the dispenser 5 at the location of the local pressure drop, which causes a pressure rise after the valve 2. The air bubbles in the following act as a spring, thus preventing further local pressure drops that could cause cavitation to develop. The air is added by means of a dispenser 5 to a natural draft that supplies air throughout the circumference of the stream. The amount of air depends on the pressure or pressure in the pipeline, but may also be limited.

Connection 6 is a short pipeline connecting the dispenser 5 and the aperture 7. The form of the connection 6 depends on the layout and orientation of the whole invention, and the type of water turbine 10 and especially the chamber 8. Thus connection 6 can be a straight part of the pipeline or an adjustment knee.

Screen 7 is a very important component and has two functions:

increases the pressure behind valve 2 and consequently prevents cavitation in valve 2, produces a symmetrical, concentrated and directional flow at the inlet of chamber 8.

The shutter 7 is positioned at the inlet of the chamber 8 so that the outlet has a direct flow into the chamber 8. The shape of the aperture 7 depends on the inlet parameters.

Chamber 8 is an important component of the invention and converts kinetic energy via turbulence into potential energy (water jump). The peculiarity is that energy conversion occurs in a closed, confined and controlled space filled with water. The size of the chamber is specified on a case-by-case basis, since the energy conversion takes place in a volume of water, which must be sufficiently large to prevent the inlet current from the aperture 7 from touching the walls. Inlet current could cause vibrations, erosion and damage to the material on the walls. In the chamber 8, so much inlet kinetic energy is converted that at outlet 9 the flow velocity is such that the flow does not damage the river bed. In chamber 8, all the turbulence resulting from the conversion of energy from kinetic to potential is also converted.

Exit 9 is the connection between the outlet of the chamber 8 and the river, or depending on the embodiment, it may also connect the chamber 8 to the existing lower channel connecting the suction tube of the turbine to the river. Outlet 9 is designed in such a way that the calm stream coming from chamber 8 is evacuated by the shortest path into the river.

The essence of the invention is explained in more detail below with the description of the embodiment and the attached sketch, the sketch being part of the present patent application and the sketch showing:

Figure 1 shows the inlet 1, valve 2, valve drive 3, valve synchronization with turbine blades 4, dispenser 5, connection 6, diaphragm 7, chamber 8, outlet 9, water turbine 10, oil servomotor 11 and water servomotor 12.

The circulation discharge for controlled and space-limited conversion of water potential consists of several components that are dimensionally adjusted according to the inlet parameters and according to the layout of the turbine.

The first component is the inlet 1, which connects the water turbine 10 at the spiral housing location and the valve 2. The valve 2 is dimensioned and shaped so that the water path from the water turbine 10 to the valve 2 is as short as possible and controls cavitation and erosion and its operation is unconditionally.

The valve 2 is opened and closed via a valve actuator 3, which comprises an oil servomotor 11 and a water servomotor 12. The water servomotor 12 is directly connected to the water pressure in the pipeline before the water turbine 10 and forces the valve to open. The oil servomotor 11 holds the valve 2 in the closed position and acts in the opposite direction of the water servomotor 12. In the event of a fall in oil pressure in the oil servomotor 11, due to a power failure or failure of the hydraulic unit, the water servomotor 12 opens the valve 2 safely.

When shutting down the water turbine 10, synchronization of the valve with the guide blades of the turbine 4 via the actuator of valve 3 ensures that valve 2 is opened so that the total flow of water through the water turbine 10 and valve 2 does not change during closing of the guide blades of the turbine. After the shutdown of the water turbine 10 is closed, valve 2 is slowly closed so that the pressure changes in the pipeline are small or the circulation discharge is passed for controlled and spatially limited conversion of the water potential into continuous operation. When starting the water turbine 10, valve 2 closes synchronously by opening the guide blades of the water turbine 10 and the process is reversed.

By adding air with the dispenser 5 at the location of the local pressure drop behind valve 2, a pressure rise is induced, which prevents excessive pressure drops and the associated cavitation. The air is added by means of a dispenser 5 to a natural draft that supplies air throughout the circumference of the stream. The amount of air depends on the pressure or pressure in the pipeline.

Connection 6 is a short straight section of the pipeline connecting the dispenser 5 and the aperture 7. The shutter 7 is positioned at the inlet of the chamber 8 so that the outlet has a direct flow into the chamber 8.

Chamber 8 converts kinetic energy via turbulence into potential energy. The inlet kinetic energy is converted in chamber 8 so that at the outlet 9 the flow velocity is such that the flow does not damage the river bed. Exit 9 is the connection between the outlet of chamber 8 and the river.

It is understood that the described solution can also be implemented in a different design that does not alter the essence of the invention.

Claims (14)

1. Circulating discharge for controlled and spatially limited conversion of water potential, characterized in that it comprises inlet (1), valve (2), valve actuator (3), synchronization of the valve with turbine blades (4), dispenser (5), connection (6), aperture (7), chamber (8), and outlet (9), wherein the discharge valve (2) is synchronized with the guide blades of the water turbine (10). The invention according to claim 1, characterized in that the valve (2) is opened via a valve actuator (3) comprising an oil servomotor (11) and a water servomotor (12). The invention according to any one of claims 1 to 2, characterized in that the water servomotor (12) is directly connected to the water pressure in the pipeline before the water turbine (10) and forces the valve (2) to open. The invention according to any one of claims 1 to 3, characterized in that the oil servomotor (11) holds the valve (2) in the closed position and acts in the opposite direction of the water servomotor (12). The invention according to any one of claims 1 to 4, characterized in that, in the event of an oil pressure drop in the oil servomotor (11), due to a power failure or failure of the hydraulic unit, the water servomotor (12) opens the valve (2). The invention according to any one of claims 1 to 5, characterized in that, at the fast closing of the water turbine (10), the flow of water is diverted via the valve (2) to the circulation discharge for controlled and spatially limited conversion of water potential. The invention according to any one of claims 1 to 6, characterized in that when shutting down the water turbine (10), synchronization of the valve with the guide blades of the turbine (4) through the actuator of the valve (3) provides for the opening of the valve (2), that the total flow of water through the water turbine (10) and the valve (2) does not change during the closing of the turbine guide blades. The invention according to any one of claims 1 to 7, characterized in that after the shutdown of the water turbine (10), the valve (2) is closed slowly so that the pressure changes in the pipeline are small. The invention according to any one of claims 1 to 7, characterized in that after the shutdown of the water turbine (10), the valve (2) provides continuous operation of the circulation discharge for controlled and spatially limited conversion of the water potential. The invention according to any one of claims 1 to 9, characterized in that a natural drawdown dispenser (5) places a cavitation-preventing air at the location of the local pressure drop behind the valve (2). The invention according to any one of claims 1 to 10, characterized in that the energy conversion takes place in the chamber (8), that is, in a closed confined and controlled space filled with water. The invention according to any one of claims 1 to 11, characterized in that an aperture (7) is mounted between the connection (6) and the chamber (8), which increases the pressure behind the valve (2) and consequently prevents cavitation in the valve 2. The invention according to any one of claims 1 to 12, characterized in that an aperture (7) is provided between the connection (6) and the chamber (8), which produces a symmetrical, concentrated and directed current at the inlet of the chamber (8). The invention according to any one of claims 1 to 13, characterized in that the aperture (7) is positioned at the inlet of the chamber (8) so that the outlet has a direct flow into the chamber (8).