Three set drive variable-frequency power generation systems
Technical field
The utility model relates to a kind of three units and uses transducer drive motor to realize electronic and structure that is generator operation, especially a kind of three set drive variable-frequency power generation systems be applicable to by steam turbine/motor run blower-pump load in power plant.
Background technology
In recent years, what reduce discharging along with national energy-saving puts more effort, and the industries such as power plant, mine, metallurgy, petrochemical industry carry out reducing energy consumption to existing equipment on the one hand, and the newly-built efficiency of another aspect is higher, the better equipment of energy-saving effect.Relate to the field of motor-driven, by the occasion that change motor speed can be significantly energy-conservation, frequency converter is widely used.Meanwhile, the advantage of frequency converter, as large in staring torque, impulse current is little, variable ratio frequency changer speed governing and Reactive-power control etc., also promoted the fast development of all kinds of frequency converter of high, medium and low voltage, and then the cost of frequency converter also reduced greatly.For energy savings and utilize Boiler Steam, power plant often utilizes steam turbine to drag high-power blower in factory or load of the pumps, coaxially also connects a motor and is used for starting load, after load speed reaches rated speed, motor is out of service, drags load separately by steam turbine.This three unit operation modes, turbine speed is regulated by porthole, and the power plant residual steam energy is only for load, and energy utilization rate is lower; Motor is only for three unit startings, and utilization rate of equipment and installations is low; Load is constant-speed operation, and energy resource consumption is large.
As patent literature, Authorization Notice No. is in " a kind of petrochemical industry three unit " of CN201884073U, disclosed structure comprises flue gas turbine expander, main air blower, gear box, asynchronous electric/generator and freewheel clutch, the power output shaft of flue gas turbine expander is connected by the power input shaft of freewheel clutch with main air blower one end, and the rotating shaft of asynchronous electric/generator is connected by the power input shaft of gear box with the main air blower other end.Because it directly connects electrical network by asynchronous electric/generator, therefore when flue gas turbine expander power is large, rotating speed reaches the rated speed of main air blower, flue gas turbine expander provides power, asynchronous electric/generator is in generating state, now the energy of flue gas turbine expander can all be utilized, and three units are in normal operating conditions; When flue gas turbine expander power hour, during the rated speed of rotating speed lower than main air blower, freewheel clutch is thrown off automatically, flue gas turbine expander and main air blower is made to realize automatically being separated, flue gas turbine expander does not reoffer energy, main air blower input power is all provided by the asynchronous electric/generator being in motoring condition, and energy consumption increases greatly.
Application publication number is also had to be " variable-frequency power generation unit and the coaxially arranged thermal power plant's generating set of turbo generator set " of CN104638670A, what it was recorded comprises the turbo generator set be made up of steam turbine and the first generator, and steam turbine drags the first generator with fixing speed rotary electrification; Also comprise the variable-frequency power generation unit be made up of timing gear roller box and the second generator.In fact primary structure is that steam turbine drives two generating sets, and generator can be connected to the side of steam turbine, also can be connected to the both sides of steam turbine.Steam turbine Direct driver first generator sends power frequency electric energy for sale of surfing the Net, and drives the second generator to send frequency conversion electric energy for self station service living load by timing gear roller box.Owing to there is timing gear roller box, the efficiency of system is reduced, mechanical speed governors part too increases failure rate and the maintenance of system, for the load needing different frequency requirement, adopt and concentrate frequency conversion to be difficult to realize optimum energy-saving effect, there is entirety simultaneously and invest the problems such as huge, because its scope of application is little, therefore be only suitable for the use of newly-built power plant, be not suitable for the transformation of original power plant equipment.
Utility model content
The purpose of this utility model is to provide a kind of three set drive variable-frequency power generation systems, solve existing three set drive and there is the problems such as mechanical speed governors efficiency is low, energy consumption is large, the scope of application is little, its structural design is simple, improve transmission efficiency and reliability of operation, residue mechanical energy and equipment rated capacity can be made full use of, and realize rotational speed regulation, reduction electric motor starting electric current and reduce the functions such as electrical network impact, energy-saving effect is remarkable, has widened the scope of application.
The technical scheme that the utility model adopts is: this three set drive variable-frequency power generation system comprises three units and the frequency converter of prime mover, fans load and motor formation, its technical essential is: described prime mover, fans load and motor coaxle are interconnected, prime mover is connected with one end of fans load, and the other end of fans load is connected with motor; Between motor and electrical network, arrange frequency converter, inverter input is connected with electrical network, and inverter output terminal is connected with motor, under Frequency Converter Control, carry out rotational speed regulation to three units, has variable frequency starting, normal operation, failure operation three kinds of operating modes.
Described frequency converter is four-quadrant frequency converter, is connected with electrical network high voltage bus, controls motor and is in running status that is electronic or generating.
The advantage that the utility model has and good effect are: because the utility model is at prime mover (steam turbine or flue gas turbine expander), the basis of three set drive structures of fans load and motor composition is improved, by prime mover, fans load and motor coaxle are interconnected, a frequency converter is only set between motor and electrical network, and the input of frequency converter is connected with electrical network, output is connected with motor, under Frequency Converter Control, rotational speed regulation is carried out to three units, composition has variable frequency starting, normal operation, the transmission variable-frequency power generation system of failure operation three kinds of operating modes, so its structural design is simple, improve transmission efficiency and reliability of operation, residue mechanical energy and equipment rated capacity can be made full use of, and realize rotational speed regulation, reduce electric motor starting electric current and reduce the functions such as electrical network impact.
Specifically, control energy by frequency converter exactly and transmit between coaxial three units connected, and regulate the rotating speed of three units, realize energy-saving and cost-reducing.General under variable frequency starting operating mode, to be connected with motor by frequency converter and can to realize nominal torque and start, reduce starting current, make electrical network impulse current be less than rated current, startup is steady, improve startability.Under accidental conditions, supply energy to fans load by prime mover, frequency converter keeps being connected with motor and electrical network, when prime mover energy shortage or surplus, by Frequency Converter Control motor powered or generator operation, from electrical network makeup energy or excess energy is sent into electrical network.Meanwhile, frequency converter can control three units according to manufacturing technique requirent and run under different rotating speeds, and reduce the energy consumption of fans load further, because not having timing gear roller box, therefore transmission efficiency is high, can realize optimum energy-saving effect.Under accident operating condition, when prime mover breaks down, can by the load running of frequency converter Driving Fan; When frequency converter breaks down, by the load running of prime mover Driving Fan.
Therefore, the utility model not only solves existing three set drive and there is the problems such as mechanical speed governors efficiency is low, energy consumption is large, the scope of application is little, easily applies, and compares with existing like product, widened the scope of application.Be not only applicable to newly-built power plant situation, be equally applicable to existing power plant equipment reducing energy consumption yet.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the utility model is further described.
Fig. 1 is a kind of structural representation of the present utility model.
In figure, sequence number illustrates: 1 prime mover, 2 fans loads, 3 motors, 4 frequency converters, 5 electrical networks.
Embodiment
Concrete structure of the present utility model is described in detail according to Fig. 1.This three set drive variable-frequency power generation system comprises three units and the parts such as frequency converter 4 that prime mover 1, fans load 2 and motor 3 form.Its prime mover 1, fans load 2 are coaxially interconnected with motor 3, and prime mover 1 is connected with one end of fans load 2, and the other end of fans load 2 is connected with motor 3; Frequency converter 4 is set between motor 3 and electrical network 5, frequency converter 4 input is connected with electrical network, frequency converter 4 output is connected with motor 3, can carry out rotational speed regulation to three units under frequency converter 4 controls, composition has the transmission variable-frequency power generation system of variable frequency starting, normal operation, failure operation three kinds of operating modes.
In the present embodiment, frequency converter 4 is four-quadrant frequency converter, is connected with electrical network 5 high voltage bus, and input voltage is 6kV or 10kV, can control motor 3 and be in running status that is electronic or generating, and regulate the rotating speed of three units.
Three set drive variable-frequency power generation systems of composition, the variable frequency starting had, normal operation, failure operation three kinds of operating modes are described in detail as follows:
1) variable frequency starting.Be with fans load 2 to start by frequency converter 4 dragging motor 3, detent torque can reach nominal torque, within starting current is limited in rated current.
2) normally run.After system has started, supply power to fans load 2 by prime mover 1, frequency converter 4 is still connected with motor 3 and electrical network 5.When there is excess energy, and when equipment does not reach specified, motor 3 can be made to be operated in generating state, to send certain electric energy by frequency converter 4 to electrical network 5, make prime mover 1 power output equal fans load 2 demand power and motor 3 generated output sum; When prime mover 1 energy shortage, frequency converter 4 absorbs certain controlling electric energy motor 3 electric operation from electrical network 5, makes fans load 2 demand power equal prime mover 1 power output and motor 3 power output sum.Three generating unit speeds control regulate motor 3 to absorb from electrical network 5 by frequency converter 4 and send active power to realize.When fans load 2 traffic demand reduces, frequency converter 4 controls motor 3 and reduces power stage from from electrical network 5 to three units, and rotating speed is reduced; When fans load 2 traffic demand increases, frequency converter 4 controls motor 3 increases power stage from from electrical network 5 to three units, makes rotating speed increase.Under in whole service process, three generating unit speeds maintain given rotating speed all the time.When power adjustments is when exceeding equipment rated value, limit excessive input power by regulating the air door of prime mover 1.
3) failure operation.When prime mover 1 breaks down, air door can be closed and stop prime mover 1 to exert oneself, be run by the independent Driving Fan load 2 of frequency converter 4; When frequency converter 4 breaks down, frequency converter 4 cuts out output automatically, and motor 3 is in free-runing operation state, and run by the independent Driving Fan load 2 of prime mover 1, feasible system does not shut down operation.