CN101725135A - Hydraulic power reutilization and efficient power generation method and system in large scale hydropower station - Google Patents

Abstract

The invention discloses hydraulic power reutilization and efficient power generation method and system in a large scale hydropower station. The method is characterized in that two or more hydraulic generator groups are arranged in the proper positions of different water heads along a water reservoir from the upper part to the lower part; the caliber of a draft pipe is larger than that of a pressure diversion pipe; and the installed capacities of all the hydraulic generator groups can be the same and also can not be the same. To a newly-built large scale hydropower station or a newly-scheduled large scale hydropower station, an optimization-computat method can be adopted to determine optimum positions along the water reservoir from the upper part to the lower part to arrange two or more hydraulic generator groups so as to ensure that the installed capacity or the generated output of hydraulic generator group reaches maximum, and the energy of the water flow flowing from the high part to the lower part at high speed is furthest utilized for power generation. To the operated hydropower station, larger water potential energy can be obtained by increasing the drop height of the water flow to be converted into electric power, therefore, water flow capacity is saved; and the difference value between the water velocity of the pressure diversion pipe and the water velocity of the draft pipe is increased, and the kinetic energy component of the hydraulic power is increased to be converted into electric power, therefore, the power generation efficiency is improved.

Description

Large hydropower station water can recycling and efficient electric power generation method and system

Technical field

The present invention relates to a kind of large hydropower station water energy recycling and efficient electric power generation method and system, belong to the hydroelectric generation field.

Background technology

The power station utilizes reservoir to come retaining, and the water yield of the big more storage of reservoir capacity is big more, and the water that reservoir stores can be just many more.Current with certain flow rate contain kinetic energy, and the high more kinetic energy that has of flow velocity is just big more; The current that are in certain altitude have potential energy, and the big more potential energy that has of relative altitude is just big more.Current flow to lower from eminence, potential energy can be converted into kinetic energy, and current obtain higher speed.The water of saving in the reservoir obtains high speed under action of gravity, move along pressure diversion conduit is defeated downwards, obtains higher speed at hydraulic turbine interface.The water current driven hydraulic turbine with certain speed rotates, and makes the hydraulic turbine obtain mechanical energy; The water wheels machine driving generator is converted into electric energy with mechanical energy.Power station hydraulic generator unit output Power Calculation formula all adopts following mathematical formulae traditionally ^[1]-[13]:

P＝9.80ηQH (1)

P is a hydraulic generator unit power output (kW) in the formula, and Q is a generating flow, and H is a productive head, and η is a hydraulic turbine generating efficiency.

Formula (1) is to draw under hypothesis pressure diversion conduit entrance water velocity, pressure and prerequisite that hydraulic turbine delivery port place water velocity, pressure equate.That is to say that the Traditional calculating methods of hydraulic generator unit power output includes only potential energy, and do not comprise kinetic energy, pressure energy.Traditional calculating methods, do not consider that water flow dynamic energy and pressure energy move at reservoir, pressure diversion conduit, the hydraulic turbine, the defeated of draft tube, therefore on structure and technology, reservoir, pressure diversion conduit, the hydraulic turbine, draft tube are not carried out specific aim improvement and optimization yet, make that water can not obtain fully and efficiently utilizing.

The electric energy that the hydraulic generator unit is transformed from reservoir water body potential energy, kinetic energy and pressure energy main and reservoir drop, pressure diversion conduit entrance water velocity and reservoir filling water level etc. have relation.

HYDROELECTRIC ENERGY is to be the main resource of taking into account other comprehensive utilizations with the generating, in order to carry out reasonable optimizing to its utilization, must obtain its total amount by mathematical method, sets up function model.HYDROELECTRIC ENERGY is to be transformed by the energy that natural water resource is contained, and mainly is to be present in the energy that pressure energy, potential energy, impact kinetic energy and water body gravity acting in the water body are produced.

(1) energy that has of water inlet water body infinitesimal

Suppose that power station unit pressure deferent is cylindrical, one of water inlet little length on the x direction is the water body infinitesimal of dx, and then the stressed of this water body infinitesimal has gravity, hydraulic pressure to reach reservoir level Four water body weight force component by force to its active force.Under these active force actings in conjunction, the water body infinitesimal to the outlet campaign and promote the water wheels unit and rotate, is finally realized the coupling conversion of water energy-mechanical energy-electric energy along the pressure diversion conduit import, and the hydraulic generator unit produces electric energy output.

Pressure along the pressure diversion conduit durection component to water body infinitesimal institute's work or the energy W that had _IFor:

$W_I=P_I{V}_W=(H-H_I)\mathrm{\ρ}\·\frac{1}{4}\mathrm{\π}{D}^2\mathrm{dx}=\frac{1}{4}\mathrm{\π\ρ}{D}^2(H-H_I)\mathrm{dx}---\left(2\right)$

P wherein _I, V _W, H _I, D is volume, pressure, water level, the diameter of pressure diversion conduit entrance water body infinitesimal, H is the reservoir filling water level, ρ is the proportion of water, α is the pressure diversion conduit angle of slope.

Water body infinitesimal weight at the formed pressure in pressure diversion conduit entrance along component institute's work of pressure diversion conduit direction or the energy that is had is:

$M_I=p_M{V}_M=\frac{1}{4}\mathrm{\π}{D}^2\mathrm{\ρ}\·{\mathrm{dx}}^2---\left(3\right)$

If weight is m _W, volume is V _WThe speed of water body infinitesimal in the pressure diversion conduit water inlet be v _{I, j, i}, then its kinetic energy that has is:

$K_I=\frac{1}{2g}{m}_W{v}_I^2=\frac{1}{2g}\·\frac{1}{4}\mathrm{\π\ρ}{D}^2\mathrm{dx}\·v_I^2=\frac{1}{8g}\·\mathrm{\π\ρ}{D}^2{v}_I^2\mathrm{dx}---\left(4\right)$

Weight is m _W, volume is V _WThe water body infinitesimal have potential energy in pressure diversion conduit water inlet place and be:

$E_I=m_W\·H_I=\frac{1}{4}\mathrm{\π\ρ}{D}^2{H}_I\·\mathrm{dx}---\left(5\right)$

(2) energy that has of delivery port place water body infinitesimal

To moving to the water body infinitesimal in downstream after the hydraulic turbine acting, suppose that the pressure of power station hydraulic generator unit at hydraulic turbine delivery port place is p _O, then this pressure is m to weight _W, volume is V _WThe water body infinitesimal done be:

$W_O=p_O\·V_W=\frac{1}{4}\mathrm{\π}{D}^2{P}_O\mathrm{dx}---\left(6\right)$

Weight is m _WThe water body infinitesimal at the formed pressure in cross section, hydraulic turbine delivery port place be along component institute's work of pressure deferent direction or the energy that is had:

$M_O=M_I=\frac{1}{4}\mathrm{\π}{D}^2\mathrm{\ρ}\·d^{2}x---\left(7\right)$

If weight is m _W, volume is V _WThe speed of water body infinitesimal at hydraulic turbine delivery port place be v _O, then its kinetic energy that has is:

$K_O=\frac{1}{2g}{m}_W{v}_O^2=\frac{1}{2g}\·\frac{1}{4}\mathrm{\π\ρ}{D}^2\mathrm{dx}\·v_O^2=\frac{1}{8g}\·\mathrm{\π\ρ}{D}^2{v}_O^2\mathrm{dx}---\left(8\right)$

Weight is m _W, volume is V _WThe water body infinitesimal at the potential energy that hydraulic turbine delivery port place has be:

$E_O=m_W\·H_O=\frac{1}{4}\mathrm{\π\ρ}{D}^2{H}_O\·\mathrm{dx}---\left(9\right)$

H wherein _OElevation for hydraulic turbine delivery port place, power station.

(3) the unit electric energy calculates

Acting moves to the aqueduct outlet to upstream water body infinitesimal through the hydraulic turbine, and according to law of conservation of energy, energy or merit that the hydraulic turbine obtains are:

$E_G=W_I+K_I+E_I+M_I-W_O-K_O-E_O-M_O$

$=\frac{\mathrm{\π}{D}^2\cos \mathrm{\α}[\mathrm{\ρ}(H-H_I)-P_o]\mathrm{dx}}{4}+\frac{\mathrm{\π\ρ}{D}^2\cos \mathrm{\α}[v_I^2-v_o^2]\mathrm{dx}}{8g}$

$+\frac{\mathrm{\π\ρ}{D}^2(H_I-H_o)\mathrm{dx}}{4}---\left(10\right)$

Make k _pBe the ratio of Hydropower Plant hydraulic turbine delivery port place with pressure deferent water inlet water body pressure:

$k_P=\frac{p_O}{p_I}---\left(11\right)$

k _vBe the ratio of step power station unit hydraulic turbine delivery port place with pressure deferent water inlet water volume flow rate:

$k_v=\frac{v_O}{v_I}---\left(12\right)$

H _DBe the drop between Hydropower Plant pressure deferent water inlet and the hydraulic turbine delivery port place:

H _D＝H _I-H _O (13)

Energy or function electrical power that the hydraulic turbine obtains are represented, then step power station j i platform unit with kW be unit (1kW=102kg.m/s) in period dt, produced exert oneself and can represent:

$N_G=\frac{1}{102}[(1-k_p)p_I+\frac{1}{2g}{v}_I^3(1-k_v)+H_D]Q_G---\left(14\right)$

Q wherein _GBe the unit generation flow,

To formula (14) arrangement:

$N_G=9.8[(1-k_p)p_I+\frac{1}{2g}{v}_I^3(1-k_v)+H_D]Q_G---\left(15\right)$

From formula (15) as can be seen, the available water of Hydropower Plant Reservoir can comprise water body pressure energy, kinetic energy, potential energy, the electric energy that utilizes the hydraulic generator unit to be obtained is relevant with power station drop, generating flow, and also the parameters such as storage capacity feature of importing and exporting pressure, speed, aqueduct inclination angle and the power station of water body with pressure diversion conduit have substantial connection.

Traditional hydraulic generator unit all is to adopt the Traditional calculating methods of above-mentioned formula (1) to determine its installed capacity.

Author of the present invention draws as drawing a conclusion through research for many years:

1) hydroelectric generator can be converted into mechanical energy by reservoir, pressure diversion conduit, the hydraulic turbine, generator and draft tube with water and be converted into electric energy, and electric energy comprises three kinds of components such as kinetic energy, potential energy and pressure energy.

2) the kinetic energy component is directly proportional with the difference of two squares of pressure diversion conduit water inlet place and hydraulic turbine delivery port place water velocity.Pressure diversion conduit water inlet place water velocity is controlled hydraulic turbine delivery port place water velocity little greatly, and the kinetic energy component will increase; Pressure diversion conduit water inlet place and hydraulic turbine delivery port place water velocity equate that the kinetic energy component is 0.

3) the pressure energy component is directly proportional with the difference of pressure diversion conduit water inlet place and hydraulic turbine delivery port place current pressure.Current suffered pressure in pressure diversion conduit water inlet place controls hydraulic turbine delivery port place current pressure little greatly, and the pressure energy component will increase; Pressure diversion conduit water inlet place and hydraulic turbine delivery port place water velocity equate that the pressure energy component is 0.

Summary of the invention

Based on above-mentioned analysis, technical problem to be solved by this invention is, a kind of large hydropower station water energy recycling and efficient electric power generation method and system are provided, at the suitable local place of different heads two places and above hydraulic generator machine group are set from top to bottom along reservoir, utilize the dynamic characteristic of reservoir head to obtain the due head of generating, the water that makes reservoir store can obtain recycling; Utilize the method for draft tube caliber, make that the kinetic energy component in the water energy is fully used, the kinetic energy transformation efficiency is improved, realize hydroelectric generation more efficiently greater than the pressure diversion conduit caliber.

Technical scheme of the present invention is as follows:

Large hydropower station water can reuse and efficient electric power generation method, 1) at the suitable local place of different heads two places and above hydraulic generator machine group are set from top to bottom along reservoir, its role is to, make that the hydraulic generator machine group all obtains maximum installed capacity or generated output everywhere.2) the delivery port caliber of draft tube its role is to greater than the water inlet caliber, by enlarging draft tube delivery port caliber, obtains pressure deferent water inlet v _IWith hydraulic turbine delivery port v _OBigger difference.At hydraulic turbine delivery port v _OUnder the less situation, make draft tube can transport the generating flow the same, make kinetic energy be converted into electric energy more with pressure diversion conduit.

Large hydropower station water can reuse and efficient power generation system, comprise reservoir, pressure diversion conduit, the middle head hydraulic turbine, middle-size and small-size capacity generator, draft tube 1 (pressure diversion conduit 5), high head hydraulic turbine, large-scale capacity generator, draft tube 2 (pressure diversion conduit 8), it is characterized in that: at the suitable local place of different heads two places and above hydraulic generator machine group are set from top to bottom along reservoir; The delivery port caliber of draft tube is greater than the water inlet caliber.

Above-mentioned large hydropower station water can reuse and efficient power generation system, described arbitrary section draft tube, and its cross sectional shape can be circle, or oval, or triangle, or square, or polygon.

The invention has the advantages that: for newly-built or plan newly-built large hydropower station, can adopt the optimization Calculation Method to determine at optimum local place two places and above hydraulic generator machine group to be set from top to bottom along reservoir, make hydraulic generator machine group installed capacity of every place or generated output reach maximization, the energy that utilizes flow at high speed current from top to bottom to be had to greatest extent generates electricity.For the power station of having moved, can carry out innovative design by the draft tube system to hydroelectric power system, increase the difference of pressure diversion conduit and draft tube water velocity, the kinetic energy component is converted into electric energy in the water energy thereby increase, improve generating efficiency, the utilization ratio of water energy is also just higher.

Description of drawings

Accompanying drawing can reuse and the schematic diagram of efficient power generation system for large hydropower station water of the present invention.

The specific embodiment

As shown in the figure, 1 is reservoir, and 2 is pressure diversion conduit, and 3 is the middle head hydraulic turbine, and 4 is middle-size and small-size capacity generator, and 5 is pressure diversion conduit, and 6 is large-scale capacity generator, and 7 is high head hydraulic turbine, and 8 is pressure diversion conduit.The water inlet of pressure diversion conduit 2 is connected with reservoir 1, and the delivery port of pressure diversion conduit 2 is connected with the water inlet of the middle head hydraulic turbine 3.The draft tube of the middle head hydraulic turbine 3 is pressure diversion conduit 5, and its caliber is greater than the caliber of pressure diversion conduit 2.Pressure diversion conduit 5 water inlets are connected with the middle head hydraulic turbine 3, and delivery port is connected with high head hydraulic turbine 7.Pressure diversion conduit 8 is the draft tube of high head hydraulic turbine 7.Pressure diversion conduit 8 water inlets are connected with high head hydraulic turbine 7, and delivery port and downstream join.Pressure diversion conduit 8 calibers are greater than pressure diversion conduit 5 calibers.

Pressure diversion conduit 2 with bore 8m is an example, for the hydraulic turbine 3, the water velocity of pressure diversion conduit 2 is 8m/s, under situation about not considering through the influence of the variation of the hydraulic turbine 3 back water velocities and other factors, if draft tube 5 calibers are the twice of the caliber of pressure diversion conduit 2, draft tube 5 is when transporting the generating flow condition the same with pressure diversion conduit 2 so, and the water velocity of the draft tube 5 of flowing through can be changed into 4m/s.If consider that part kinetic energy component is converted into mechanical energy by the hydraulic turbine 3 in the water energy, the water velocity of draft tube 5 will be less than 4m/s so, even can be littler.

For new unit, as long as balance technology and economic effect, the k that the draft tube water outlet aperture is designed to the pressure diversion conduit bore doubly just can make the draft tube water velocity reduce 1/k in when design.Reducing of draft tube water velocity just can increase the difference of pressure diversion conduit and draft tube water velocity, thereby makes that bigger water flow dynamic energy component is converted into electric energy, improves waterpower utilization rate, the high efficiency of strong water-energy generating electricity.

And,, just can realize technique effect of the present invention as long as existing draft tube is carried out structure and technologic technological transformation for old unit.

Claims (2)

1. large hydropower station water can reuse and efficient electric power generation method, it is characterized in that, at the suitable local place of different heads two places and above hydraulic generator machine group is set from top to bottom along reservoir; The draft tube caliber is greater than the pressure diversion conduit caliber; The hydraulic generator machine group installed capacity of every place can be identical, also can be inequality.

2. large hydropower station water can reuse and efficient power generation system, comprise reservoir, pressure diversion conduit, the middle head hydraulic turbine, middle-size and small-size capacity generator, draft tube 1 (pressure diversion conduit 5), high head hydraulic turbine, large-scale capacity generator, draft tube 2 (pressure diversion conduit 8), it is characterized in that: at the suitable local place of different heads two places and above hydraulic generator machine group are set from top to bottom along reservoir; The draft tube caliber is greater than the pressure diversion conduit caliber.

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