CN103051282A - Variable-frequency and industrial frequency switching device and switching method of Variable-frequency and industrial frequency switching device - Google Patents
Variable-frequency and industrial frequency switching device and switching method of Variable-frequency and industrial frequency switching device Download PDFInfo
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- CN103051282A CN103051282A CN2012103042153A CN201210304215A CN103051282A CN 103051282 A CN103051282 A CN 103051282A CN 2012103042153 A CN2012103042153 A CN 2012103042153A CN 201210304215 A CN201210304215 A CN 201210304215A CN 103051282 A CN103051282 A CN 103051282A
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Abstract
The invention discloses a variable-frequency and industrial frequency switching device and a switching method of the variable-frequency and industrial frequency switching device. The device and the method are used for the switching between the variable-frequency mode and the industrial frequency mode of an electric motor of a primary fan. The device comprises an industrial frequency bypass switch, a variable-frequency output switch, a variable-frequency input switch and a frequency converter, wherein the industrial frequency bypass switch is connected in series between the electric motor of the primary fan and a bus, the variable-frequency output switch, the frequency converter and the variable-frequency input switch are sequentially and serially connected between the electric motor of the primary fan and the bus, wherein when the mode is switched to the variable-frequency mode, the industrial frequency bypass switch is switched off, and the variable-frequency output switch and the variable-frequency input switch are closed. When the mode is switched to the industrial frequency mode, the industrial frequency bypass switch is closed, and the variable-frequency output switch and the variable-frequency input switch are switched off. The variable-frequency and industrial frequency switching device and the switching method realize the switching between the industrial frequency mode and the variable-frequency mode of the electric motor of the primary fan through the industrial frequency bypass switch, the variable-frequency output switch and the variable-frequency input switch.
Description
Technical field
The present invention relates to a kind of frequency conversion power frequency switching device shifter and changing method thereof, particularly relate to a kind of frequency conversion power frequency switching device shifter and changing method thereof of working method of the motor for switching primary air fan.
Background technology
The motor of the driving primary air fan of coal fired power generation machine of the prior art all is to be in the variable frequency work mode, and wherein said primary air fan is the blower fan of supplying with separately boiler oil preparation and the required primary air that burns.So the combustion position according to boiler is regulated intake by the mode of variable frequency work, thereby effective operating efficiency of raising primary air fan has been avoided the waste of energy.
But the vitals frequency converter as the variable frequency work of controlling motor is highly susceptible to damaging, and this is because the parts in the existing frequency converter are more and more, become increasingly complex, thereby the probability that whole frequency converter breaks down constantly promotes.Yet the motor of existing primary air fan does not have the variable frequency work pattern that frequency converter for subsequent use is controlled motor.
So need to be when frequency converter failure in the prior art, normally the artificially is set in the motor of primary air fan on the operating frequency of one fixed frequency.But because this mode adopts artificial method, thus meeting so that primary air fan is in off position within a period of time, thereby the normal operation of other parts of coal fired power generation machine has been caused great interference.Namely allow in addition rapidly motor is set on the operating frequency, but this moment primary air fan intake fix, can not effectively control the state that burns in the boiler, thereby also other parts of boiler caused interference.
Summary of the invention
The technical problem to be solved in the present invention is not seamlessly transit the defective that causes the interference of other parts of coal fired power generation machine for the power frequency mode of the motor that overcomes primary air fan in the prior art and conversion system do not have, a kind of frequency conversion power frequency switching device shifter and changing method thereof are provided, by between the power frequency mode of the motor of primary air fan and conversion system smoothly transition slow down interference to other parts of coal fired power generation machine.
The present invention solves above-mentioned technical problem by following technical proposals:
The invention provides a kind of frequency conversion power frequency switching device shifter, be used for the power frequency mode of motor of primary air fan and the switching of conversion system, be characterized in that described frequency conversion power frequency switching device shifter comprises:
One power frequency by-pass switch, a frequency conversion output switch, a frequency conversion input switch and a frequency converter; Described power frequency by-pass switch is serially connected with between the motor and a bus of described primary air fan, and described frequency conversion output switch, frequency converter and frequency conversion input switch are serially connected with between the motor and described bus of described primary air fan successively;
Wherein when switching to conversion system, described power frequency by-pass switch disconnects, and described frequency conversion output switch and described frequency conversion input switch are closed; When switching to the power frequency mode, described power frequency by-pass switch is closed, and described frequency conversion output switch and described frequency conversion input switch disconnect.
Wherein the mode of power frequency described in the present invention refers to that the motor of primary air fan directly uses the AC power with fixed frequency of industrial use, and described conversion system just refers to the changeable AC power of motor frequency of utilization of primary air fan.Because under the power frequency mode, the power of described motor output fixing, such as rated power etc., yet the process of boiler oil burning is a process that constantly changes, the air quantity that required primary air fan is blown into changes, so use the power frequency pattern can cause the waste of the power of motor, and the employing conversion system, change the power of primary air fan output by the frequency that changes power supply, thereby the frequency of regulating described power supply based on the state of boiler oil burning, improve effectively power utilization, avoided waste.
But because the frequency converter that uses in the conversion system is easily worn part, thereby when frequency converter damages, can't provide power supply for the motor of primary air fan, yet there is not this problem in the power frequency mode, so in order to guarantee to use the equipment requirements such as coal fired power generation machine of primary air fan to move all the time, so supply power mode of motor when also needing to introduce the power frequency mode and substituting described frequency converter and damage.Also be convenient to simultaneously repairing and replacement to frequency converter, and also need effective level and smooth mode to switch to variable mode from the power frequency mode after repairing.So the interlock by power frequency by-pass switch, frequency conversion output switch and frequency conversion input switch among the present invention realizes the switching of the power supply of the power supply of power frequency mode and conversion system.
Preferably, described frequency conversion power frequency switching device shifter also comprises a differential protection unit, and for the internal fault of the motor that suppresses described primary air fan, wherein when switching to the power frequency mode, described differential protection unit accesses the motor of described primary air fan; When switching to conversion system, the motor of described differential protection unit and described primary air fan disconnects.
Differential protection unit described in the present invention is exactly the equipment of widely used differential protection to motor in the prior art, so just no longer at length set forth among its structure and implementation the present invention.
Because when motor directly is connected with bus, in order to prevent the internal fault of motor.Internal faults such as winding interturn short-circuit, ground connection; must need to adopt the device of the differential protection of phase angle pattern; but because existing frequency converter realizes preventing that with mode by the control phase angle internal fault of motor from being incompatible; so among the present invention only when motor switches to the power frequency mode; differential protection unit is dropped into, thereby motor is protected.
So preferably, described differential protection unit is serially connected with between the motor and described power frequency by-pass switch of described primary air fan.
Preferably, described frequency converter also is used for suppressing overcurrent, zero sequence, low-voltage and the overload of the motor of described primary air fan.
Frequency converter described in the present invention is the general frequency converter that is used for variable frequency control in the prior art; and all have the function of overcurrent, zero sequence, low-voltage and overload of protection motor in the existing frequency converter, so no longer the function that how to realize described overcurrent, zero sequence, low-voltage and overload in the frequency converter is at length set forth herein.
Because the function of described overcurrent, zero sequence, low-voltage and the overload of integrated protection motor in the existing frequency converter, so no longer need to add separately protection to overcurrent, zero sequence, low-voltage and the overload of motor among the present invention.
Preferably, described frequency conversion power frequency switching device shifter also comprises a DCS control system (Distributed Control System, dcs), wherein when described DCS control system detects the heavy fault-signal of frequency converter, disconnect described power frequency by-pass switch and closed described frequency conversion output switch and described frequency conversion input switch.
The general frequency converter that is used for variable frequency control in the prior art can also provide light fault signal and heavy fault-signal etc. to external equipment based on the operating state of frequency converter, so no longer at length set forth the principle of signals such as generating light fault signal and heavy fault-signal in the described frequency converter and the structure of frequency converter correspondingly among the present invention.
Because when frequency converter sends the light fault signal, existing frequency converter also has certain regulatory function, so can also keep the normal operation of self, so the staff can carry out the preparation that conversion system switches to the power frequency mode based on whole coal fired power generation unit etc., thereby so that the air quantity that primary air fan is blown into can not cause serious interference to boiler combustion etc.
But when frequency converter sent heavy fault-signal, frequency converter can count the state of quitting work at once, thus need to switch at once the power frequency mode this moment, thus avoid the shutdown of primary air fan to cause the fault of whole coal fired power generation unit.So utilize the DCS control system to receive the function of the heavy fault-signal that frequency converter sends among the present invention, automatically switch at once the power frequency mode.
Described DCS control system is the control system of commonly using in the coal fired power generation machine in the prior art in addition, so no longer it is at length set forth herein.
Preferably, described DCS control system also is used for regulating according to the working state control of a boiler that uses described primary air fan the baffle plate of described primary air fan.
Because when the DCS control system receives the function of the heavy fault-signal that frequency converter sends, automatically switch at once the power frequency mode and still can cause interference to boiler combustion etc., and owing to be in the power frequency mode this moment, so the power rating of primary air fan, thereby the air quantity that is blown into is specified.For so that the situation of the air quantity that is blown into and boiler combustion coupling, so utilize the operating state of the baffle plate of primary air fan and boiler to realize the adjusting of the air quantity that is blown into by the DCS control system among the present invention.Thereby reduced further the switching of frequency conversion power frequency to the impact of boiler combustion.
Preferably, described power frequency by-pass switch and described frequency conversion output switch interlocking.
Preferably, described power frequency by-pass switch and described frequency conversion input switch interlocking.
The present invention is with the mode of the switch between the switch between power frequency mode median generatrix and the motor and conversion system median generatrix, frequency converter and the motor by interlocking, so that only have all the time a switch closure at synchronization, another switch disconnects, thereby guarantee the correctly switching of power frequency mode and conversion system, avoid the generation of other misoperations.
Preferably, described power frequency by-pass switch, frequency conversion output switch and frequency conversion input switch are vacuum switch.
Because the bus of the motor of primary air fan is generally the power supply of 10KV described in the present invention, so effect for the closed and disconnected that guarantees switch, described power frequency by-pass switch, frequency conversion output switch and frequency conversion input switch preferably adopt vacuum switch, especially the vacuum switch of 10KV.
The present invention also provides a kind of conversion system of the motor for primary air fan to switch the method for power frequency mode, is characterized in using aforesaid frequency conversion power frequency switching device shifter, and may further comprise the steps:
S
11, the output frequency of described frequency converter is adjusted to one first rated frequency;
S
12, disconnect described frequency conversion output switch and frequency conversion input switch;
S
13, wait for one first Preset Time after, closed described power frequency by-pass switch.
The present invention is switched in the process of power frequency mode at conversion system, need to be after the power supply that disconnects conversion system, and after residual voltage disappears in the wait motor, by the power frequency mode motor is being powered, thereby preventing that the switching of supply power mode is to the infringement of motor.
The frequency of powering in this external conversion system increases to maximum, thereby avoids conversion system power supply and power frequency mode confession electric output power gap too large, thereby so that the switching of supply power mode to the infringement of motor.
For the characteristics of frequency converter and motor in the Power supply process of the common electrical network of China, preferably described the first rated frequency is set as 50Hz among the present invention.And described the first Preset Time is set as 3 seconds.
Preferably, described frequency conversion power frequency switching device shifter also comprises a differential protection unit, and at step S
13In also comprise lower step: described differential protection unit accesses the motor of described primary air fan.
In addition in order when the power frequency mode is powered, to protect motor, so when switching to the power frequency mode, differential protection unit is dropped into to protect motor.
The present invention also provides a kind of power frequency mode of the motor for primary air fan to switch the method for conversion system, is characterized in using aforesaid frequency conversion power frequency switching device shifter, and may further comprise the steps:
S
21, the charging of described frequency converter;
S
22, wait for one second Preset Time after, disconnect described power frequency by-pass switch;
S
23, wait for one the 3rd Preset Time after, described frequency converter stops charging and closed described frequency conversion output switch and frequency conversion input switch.
Because existing frequency converter needs the initialization operations such as precharge in start-up course, so need certain start-up time, therefore the present invention is switched in the process of conversion system in the power frequency mode, need in advance frequency converter to be charged, thereby when the described frequency conversion output switch of closure and frequency conversion input switch, frequency converter can provide electric energy for motor at once.
Simultaneously equally need to be after the power supply that disconnects the power frequency mode, after residual voltage disappears in the wait motor, by conversion system motor is being powered, thereby preventing that the switching of supply power mode is to the infringement of motor.
And in order to improve the switch speed of power frequency frequency conversion, the operation of the charging of described wait residual voltage disappearance and frequency converter can be carried out simultaneously.
Preferably, described the second Preset Time is 4.7 seconds.
Preferably, described the 3rd Preset Time is 0.3 second.
For the characteristics of frequency converter in the prior art and motor, preferably described the second Preset Time is set as 4.7 seconds among the present invention.And described the 3rd Preset Time is set as 0.3 second.
Preferably, described frequency conversion power frequency switching device shifter also comprises a differential protection unit, and at step S
23In also comprise lower step: the motor of described differential protection unit and described primary air fan disconnects.
In addition since the power frequency mode when powering to the differential protection mode of the protection of motor, when the power frequency mode was powered, the load object was motor.Regulation parameter frequency 50Hz in the microcomputer protecting device current techique; so Digital Signal Processing wherein is based on Fourier transform; Fourier transform has the fundamental frequency can only the computes integer order harmonic components; so the microcomputer protecting device operated by rotary motion has low pass filter, and the fundamental frequency following range of Fourier transform is 45 ~ 50Hz.Thereby much smaller than the frequency converter transformation range, so differential protection is not suitable for the frequency conversion loop.So when conversion system is powered, need withdraw from differential protection.
The present invention also provides a kind of conversion system of the motor for primary air fan to switch the method for power frequency mode, is characterized in using aforesaid frequency conversion power frequency switching device shifter, and may further comprise the steps:
S
31, described DCS control system detects described frequency converter and whether sent heavy fault-signal, if then enter step S
32, otherwise repeating step S
31
S
32, disconnect described frequency conversion output switch and frequency conversion input switch;
S
33, wait for one the 4th Preset Time after, closed described power frequency by-pass switch.
Preferably, described the 4th Preset Time is 3 seconds.
For the characteristics of frequency converter and motor in the coal fired power generation unit in the prior art, preferably described the 4th Preset Time is set as 3 seconds among the present invention, thereby can satisfies specification requirements such as waiting for the residual voltage disappearance.
Preferably, described DCS control system also is used for the baffle plate of the described primary air fan of regulating and controlling, and at step S
33Also comprise afterwards lower step:
Described DCS control system is regulated the baffle plate of described primary air fan according to the operating state of a boiler that uses described primary air fan.
When switching to the power frequency mode owing to the heavy fault-signal based on frequency converter, whole coal fired power generation unit does not carry out the adjustment of any parameter, so the inevitable requirement with boiler combustion of the air quantity that this moment, primary air fan provided is unmatched, so boiler combustion has been produced disturbance, therefore cover intake by the baffle plate in the primary air fan among the present invention, thereby can regulate according to the state of boiler combustion the intake of boiler, thereby so that when the power frequency mode was worked, the boiler combustion of coal fired power generation unit still can keep good combustion efficiency.
Preferably, described frequency conversion power frequency switching device shifter also comprises a differential protection unit, and at step S
33In also comprise lower step: described differential protection unit accesses the motor of described primary air fan.
Positive progressive effect of the present invention is:
Frequency conversion power frequency switching device shifter of the present invention and changing method thereof have been realized the power frequency mode of motor of primary air fan and the switching of conversion system by power frequency by-pass switch and frequency conversion output switch and frequency conversion input switch, because described power frequency by-pass switch and frequency conversion output switch and frequency conversion input switch are interlocking linkages, so when breaking away from conversion system, must enter the power frequency mode, when breaking away from the power frequency mode, must enter conversion system, so realized smoothly transition between the power frequency mode of motor of primary air fan and the conversion system.
In addition, also by when entering the power frequency mode, add differential protection, when breaking away from the power frequency mode, the cancellation differential protection, thus avoided the conflict of the safeguard measure of the safeguard measure of power frequency mode and conversion system.Thereby effectively protect the motor of primary air fan.
In addition; utilize existing frequency converter that the signal of faults itself situation can be provided; when the inner heavy fault of frequency converter, automatically switch to the power frequency mode by the DCS control system, thereby avoided frequency converter to damage the generation of the situations such as shutdown of the motor of the primary air fan that causes.
Description of drawings
Fig. 1 is the structural representation of the preferred embodiment of frequency conversion power frequency switching device shifter of the present invention.
Fig. 2 is the flow chart that a kind of conversion system of preferred embodiment of the present invention switches the power frequency mode.
Fig. 3 is the flow chart that a kind of power frequency mode of preferred embodiment of the present invention is switched conversion system.
Fig. 4 is the flow chart that the another kind of conversion system of preferred embodiment of the present invention switches the power frequency mode.
Embodiment
Provide preferred embodiment of the present invention below in conjunction with accompanying drawing, to describe technical scheme of the present invention in detail.
Embodiment:
Because nominal situation next time blower fan moves with conversion system.Simultaneously; for satisfying when the frequency converter failure; do not affect whole coal fired power generation unit operation; the reliability of raising system, availability and continuity; so need to be at the coal fired power generation unit in non-stop-machine situation; the motor of primary air fan is switched to the power frequency mode smoothly from the conversion system operation move, equally also can be after maintenance or changing frequency converter, the motor of primary air fan moved from the power frequency mode switch to smoothly the conversion system operation.
For this reason as shown in Figure 1, comprise a power frequency by-pass switch 1, a frequency conversion output switch 2, a frequency conversion input switch 3, a frequency converter 4, a differential protection unit 5 and a DCS control system 6 in the frequency conversion power frequency switching device shifter of present embodiment.
Wherein said power frequency by-pass switch 1 is serially connected with between the motor 7 and a bus 8 of primary air fan, and described frequency conversion output switch 2, frequency converter 4 and frequency conversion input switch 3 are serially connected with between the motor 7 and described bus 8 of described primary air fan successively.
Wherein the motor 7 of the primary air fan of present embodiment is applied to 900,000 kilowatts coal fired power generation unit, think that the bus 8 of the power supply that the motor 7 of described primary air fan provides is the 10KV bus, same switch motion in order to remain valid under 10KV, described power frequency by-pass switch 1, frequency conversion output switch 2 and frequency conversion input switch 3 are the vacuum switch of 10KV.
When needs switched to frequency conversion, described power frequency by-pass switch 1 disconnected described frequency conversion output switch 2 and described frequency conversion input switch 3 closures in the present embodiment.Same when needs switch to power frequency, described power frequency by-pass switch 1 closure, described frequency conversion output switch 2 and described frequency conversion input switch 3 disconnect.
And in the handoff procedure of frequency conversion power frequency, from the power frequency mode enter process that conversion system or conversion system enter the power frequency mode be continuously, without the handoff procedure in the time interval, so the by-pass switch of power frequency described in the present embodiment 1 and 2 interlockings of described frequency conversion output switch, thereby only having all the time a switch closure at synchronization, another switch disconnects.So guarantee that the motor of primary air fan is not to be in the power frequency mode to be in exactly conversion system, thereby can not cause all situation generations closed or that all disconnect of power frequency by-pass switch 1 and described frequency conversion output switch 2 because of misoperation.
In addition the developer can also be as required so that other switch interlock in described power frequency by-pass switch 1 and the frequency conversion loop, for example, power frequency by-pass switch 1 and 3 interlockings of described frequency conversion input switch realize identical function.Just give unnecessary details no longer in detail herein.
And owing to when the power frequency mode is moved, require to drop into differential protection as the main protection of motor.So the differential protection unit 5 in the present embodiment is serially connected with between the motor 7 and described power frequency by-pass switch 1 of described primary air fan, and when the motor 7 of primary air fan moves in the power frequency mode, provides the protections such as internal fault for motor 7.And because differential protection is not suitable for the frequency conversion loop, so when the motor 7 of primary air fan moves with conversion system again, need to stop the protection of 5 pairs of described motor 7 of described differential protection unit.Therefore when switching to the power frequency mode, described differential protection unit 5 accesses the motor 7 of described primary air fan.When switching to conversion system, the motor 7 of described differential protection unit 5 and described primary air fan disconnects.Can adopt the differential protection of 7UT612 type of Siemens Company as described differential protection unit 5 in the present embodiment.
According to the requirement of operating condition, conversion system is disposed different protections targetedly with the power frequency mode in the present embodiment.Simultaneously, guarantee safety, relaying protection is moved under the correct prerequisite when adapting to power frequency and converting operation, as far as possible flexibly and convenient.When switching to the power frequency mode, although can normally move, in case cut Closing fault when move to conversion system, when needing switchback power frequency mode, locking power frequency of differential protection by-pass switch 1 combined floodgate.Even normally cut to conversion system, but when needing switchback power frequency mode, also can run into the situation of not closing power frequency by-pass switch 1.For this reason, present embodiment can adopt the 7UT612 type with differential protection unit 5, utilizes the protection in the 7UT612 type to export the purpose that automatic blocking/removing function has reached differential correct operation.Through 7UT612 type function setting; locking BO4 output during open BI2 conducting; make differential protection in situation about not withdrawing from; differential protection can normally drop into when moving in the power frequency mode; and locking differential output power frequency by-pass switch 1 action when conversion system moves; outlet action in the time of can escaping differential protection unit energising startup prevents malfunction, can correct operation when having guaranteed fault again.The LED lamp (light-emitting diode) of setting on the differential protection unit simultaneously can also the in-service monitoring operating condition.
Frequency converter commonly used is the same in frequency converter described in the present embodiment 4 and the prior art in addition, also has overcurrent, zero sequence, low-voltage and the overload of the motor 7 that suppresses described primary air fan.Because described defencive function to motor 7 all is integrated in the described frequency converter 4, so in the handoff procedure of frequency conversion power frequency, described defencive function is realized along with the input of described frequency converter 4 or excision or cancelled.
Also utilize existing frequency converter that the function of light fault signal and heavy fault-signal etc. can be provided to external equipment based on the operating state of frequency converter in the present embodiment, thereby detect frequency converter 4 by DCS control system 6 and whether sent heavy fault-signal, because when frequency converter 4 has sent heavy fault-signal, expression frequency converter 4 will quit work at once, so this moment, the DCS control system 6 need to disconnect described power frequency by-pass switch 1 and closed described frequency conversion output switch 2 and described frequency conversion input switch 3 at once, thereby being switched to the power frequency mode from the conversion system operation, the motor 7 of primary air fan moves.
And utilize further the baffle plate of primary air fan in the present embodiment, thereby when motor 7 moves in the power frequency mode, thereby DCS control system 6 comes controllable register control primary air fan to be blown into the air quantity of boiler according to the fired state of boiler in the coal fired power generation unit, even so when motor 7 moved in the power frequency mode, the coal fired power generation unit still can have higher combustion efficiency.
The below will describe the using method that the power frequency frequency conversion of the frequency conversion power frequency switching device shifter of present embodiment is switched.
Can also provide light fault signal and heavy fault-signal etc. to external equipment based on the operating state of frequency converter owing to be used for the general frequency converter of variable frequency control in the prior art.And when frequency converter sends the light fault signal, existing frequency converter also has certain regulatory function, so can also keep the normal operation of self, so the staff can carry out the preparation that conversion system switches to the power frequency mode based on whole coal fired power generation unit etc., thereby so that the air quantity that primary air fan is blown into can not cause serious interference to boiler combustion etc.
So at first be that primary air fan motor 7 provides the variable frequency work power supply by frequency converter 4 under nominal situation in the present embodiment, frequency conversion output switch 2 and frequency conversion input switch 3 are in "on" position.When unusually and not tripping appears in frequency converter 4, be that described frequency converter 4 is in the light fault state, this moment, the motor 7 of primary air fan not only can switch to the power frequency mode manually, also can use automatic mode to switch to the power frequency mode, motor 7 over against the primary air fan of embodiment, need first frequency converter 4 output frequencies to be risen to 50Hz, disconnect again frequency conversion output switch 2 and frequency conversion input switch 3, then power frequency by-pass switch 1 automatic time delay is closed after 3 seconds, and 10KV bus 8 provides power frequency supply by power frequency by-pass switch 1 for the motor 7 of primary air fan.
So in this case, as shown in Figure 2, may further comprise the steps in the process of the conversion system of the motor of primary air fan switching power frequency mode:
When frequency converter sent heavy fault-signal, frequency converter can count the state of quitting work at once, thus need to switch at once the power frequency mode this moment, thus avoid the shutdown of primary air fan to cause the fault of whole coal fired power generation unit.So receive the function of the heavy fault-signal that frequency converter sends in the present embodiment when described DCS control system, automatically switch at once the power frequency mode.
When so at first frequency converter 4 normally moves in the present embodiment, if inner heavy fault occurs in frequency converter 4, frequency converter 4 is to 6 heavy fault-signals of DCS control system, chain tripping frequency conversion output switch 2 and frequency conversion input switch 3, automatic time delay 3s again, described delay time the time is recorded by debugging, be as the criterion to satisfy specification requirement, then closed power frequency by-pass switch 1, the motor 7 of primary air fan realizes automatically switching to the power frequency mode, and after this DCS control system 6 is according to boiler combustion status in the coal fired power generation unit that receives, the baffle plate of Signal Regulation primary air fan is controlled the intake of boiler.
So in this case, as shown in Figure 4, may further comprise the steps in the process of the conversion system of the motor of primary air fan switching power frequency mode:
After this can safeguard or change the frequency converter 4 in the frequency conversion loop, after maintenance is complete, the motor 7 of primary air fan need to be entered the conversion system of more saving power consumption from the power frequency mode.
So when at first moving in the power frequency mode in the present embodiment, power frequency by-pass switch 1 is in "on" position.After frequency converter 4 receives " the power frequency shear frequently " instruction, frequency converter 4 begins charging automatically, the 4.7s that delays time simultaneously disconnects power frequency by-pass switch 1, after the 5s charging finishes, auto-closing frequency conversion output switch 2 and frequency conversion input switch 3, then frequency converter 4 detects motor 7 operation phase place and frequencies automatically, do not having in the situation of rush of current, motor 7 is dropped into converting operation, and the frequency of frequency converter 4 directly rises to 50HZ and locking frequency in charging process, and the given frequency that after this accepting DCS control system 6 provides is again carried out conversion power supply.
So in this case, as shown in Figure 3, the power frequency mode of the motor of primary air fan is switched in the process of conversion system and be may further comprise the steps:
The size that the switching power frequency mode of conversion system described in the present embodiment and power frequency mode are switched the first Preset Time described in the conversion system, the second Preset Time, the 3rd Preset Time and the 4th Preset Time and the first rated frequency all is based on the result that 900,000 kilowatts of coal fired power generation machines are debugged and tested.Wherein divide two kinds of Static and dynamics to the test of the frequency conversion power frequency switching device shifter of present embodiment.
Wherein said static debugging comprises:
1, frequency conversion input switch 3 and power frequency by-pass switch 1 relay protection check.2, wiring check, control board, PLC module (programmable logic controller (PLC)), microcomputer etc. carry out electric insulation to be measured, and two-way control electrical source exchange was less than 0.1 second etc.3, press the hard logic schematic diagram to electric hard locking verification.4, DCS control system 6 picture displies, warning verification, switching value, analog input/output are checked.5, press soft locking principle figure to the soft latching logic verification of PLC.6, frequency converter 4 and 6 uniting and adjustment of DCS control system, and in the DCS control system, force correlated condition, test respectively power frequency startup, variable frequency starting, worker's shear, have and prepare to become cut and fault change cut logic.
Described dynamic debugging comprises
1, empty load of motor debugging (clutch dismountings), the frequency converter water cooling system bringing normally into operation of primary air fan wherein, startup frequency converter in a distant place on the DCS control system.Adjust the frequency converter excitation parameter, make it to be complementary with this TV station motor.Electric current, change in voltage situation and the time of motor, mains switch side, rotating speed, vibration etc. during record 0～50Hz.Electric current, time and residual voltage data when recording unloaded power frequency/frequency conversion and switching.2, bringing onto load debugging (connection clutch), wherein the frequency converter water cooling system bringing normally into operation of primary air fan starts and drops into forced draft fan and induced draft fan, and a distant place starts frequency converter on the DCS control system.Motor directly is raised to full rotating speed from zero rotating speed, to current of electric, change in voltage situation with record ripple start-up time.Get through the air path system of 3 coal pulverizers, adjust the stator blade aperture of primary air fan, sustain pulse frequency 50Hz, blast 14000Pa, load and the temperature conditions of record frequency converter, record switch, motor side electric current.In the constant situation of air quantity, blast, carry out the stator blade aperture of blower fan and the test of blower fan frequency relation, record switch, motor side electric current.3, on-load switches debugging (operation of thermal control DCS control system), wherein under 5 grinder conditions, the frequency conversion of preparation cut is arranged frequently.Electric specialty record switching time and electromechanical shock electric current are recorded ripple to electric current and the voltage of motor, and the thermal control specialty is to switching time and blast variation recording ripple.Under 5 grinder conditions, the shear of the power frequency of preparation is arranged frequently.Electric specialty record switching time and electromechanical shock electric current are recorded ripple to electric current and the voltage of motor, and the thermal control specialty is to switching time and blast variation recording ripple.Think highly of fault at simulated frequency conversion on the spot, do without preparing frequency conversion cut frequently (heavy fault).Frequency converter is sent out heavy fault-signal to the DCS control system, frequency converter is finished change/worker's switching automatically simultaneously, after the DCS control system was received electric heavy fault-signal, primary air pressure was cut to the control of blower fan stator blade automatically by frequency converter, and fault-free side primary air fan frequency rises to 50Hz automatically.Fault (switching unsuccessful) was thought highly of in frequency conversion when the simulation nothing was prepared frequency conversion cut frequency, triggered primary air fan RB(Runback, retreated) logic, carry out the residual voltage test.
By above-mentioned Static and dynamic debugging, can obtain based on the specification requirement of coal fired power generation unit the optimal value of parameters size in the present embodiment.Actual adopt described optimal value to be, take every annual energy output as 10,000,000,000 calculating, every unit can be saved 2100 tons in mark coal the whole year, by 900 yuan of calculating of mark coal per ton, estimates that every unit can save 1,890,000 yuan every year.
Although more than described the specific embodiment of the present invention, it will be understood by those of skill in the art that these only illustrate, protection scope of the present invention is limited by appended claims.Those skilled in the art can make various changes or modifications to these execution modes under the prerequisite that does not deviate from principle of the present invention and essence, but these changes and modification all fall into protection scope of the present invention.
Claims (21)
1. frequency conversion power frequency switching device shifter is used for the power frequency mode of motor of primary air fan and the switching of conversion system, it is characterized in that described frequency conversion power frequency switching device shifter comprises:
One power frequency by-pass switch, a frequency conversion output switch, a frequency conversion input switch and a frequency converter; Described power frequency by-pass switch is serially connected with between the motor and a bus of described primary air fan, and described frequency conversion output switch, frequency converter and frequency conversion input switch are serially connected with between the motor and described bus of described primary air fan successively;
Wherein when switching to conversion system, described power frequency by-pass switch disconnects, and described frequency conversion output switch and described frequency conversion input switch are closed;
When switching to the power frequency mode, described power frequency by-pass switch is closed, and described frequency conversion output switch and described frequency conversion input switch disconnect.
2. frequency conversion power frequency switching device shifter as claimed in claim 1, it is characterized in that, described frequency conversion power frequency switching device shifter also comprises a differential protection unit, internal fault for the motor that suppresses described primary air fan, wherein when switching to the power frequency mode, described differential protection unit accesses the motor of described primary air fan; When switching to conversion system, the motor of described differential protection unit and described primary air fan disconnects.
3. frequency conversion power frequency switching device shifter as claimed in claim 2 is characterized in that, described differential protection unit is serially connected with between the motor and described power frequency by-pass switch of described primary air fan.
4. frequency conversion power frequency switching device shifter as claimed in claim 1 is characterized in that, described frequency converter also is used for suppressing overcurrent, zero sequence, low-voltage and the overload of the motor of described primary air fan.
5. such as each described frequency conversion power frequency switching device shifter among the claim 1-4, it is characterized in that, described frequency conversion power frequency switching device shifter also comprises a DCS control system, wherein when described DCS control system detects the heavy fault-signal of frequency converter, disconnect described frequency conversion output switch and described frequency conversion input switch and closed described power frequency by-pass switch.
6. frequency conversion power frequency switching device shifter as claimed in claim 5 is characterized in that, described DCS control system also is used for regulating according to the working state control of a boiler that uses described primary air fan the baffle plate of described primary air fan.
7. such as each described frequency conversion power frequency switching device shifter among the claim 1-4, it is characterized in that described power frequency by-pass switch and the interlocking of described frequency conversion output switch.
8. such as each described frequency conversion power frequency switching device shifter among the claim 1-4, it is characterized in that described power frequency by-pass switch and the interlocking of described frequency conversion input switch.
9. frequency conversion power frequency switching device shifter as claimed in claim 1 is characterized in that, described power frequency by-pass switch, frequency conversion output switch and frequency conversion input switch are vacuum switch.
10. the method for the conversion system switching power frequency mode of the motor of primary air fan is characterized in that, uses frequency conversion power frequency switching device shifter as claimed in claim 1, and may further comprise the steps:
S
11, the output frequency of described frequency converter is adjusted to one first rated frequency;
S
12, disconnect described frequency conversion output switch and frequency conversion input switch;
S
13, wait for one first Preset Time after, closed described power frequency by-pass switch.
11. conversion system as claimed in claim 10 switches the method for power frequency mode, it is characterized in that described the first rated frequency is 50Hz.
12. conversion system as claimed in claim 10 switches the method for power frequency mode, it is characterized in that described the first Preset Time is 3 seconds.
13. conversion system as claimed in claim 10 switches the method for power frequency mode, it is characterized in that described frequency conversion power frequency switching device shifter also comprises a differential protection unit, and at step S
13In also comprise lower step: described differential protection unit accesses the motor of described primary air fan.
14. the power frequency mode for the motor of primary air fan is switched the method for conversion system, it is characterized in that, uses frequency conversion power frequency switching device shifter as claimed in claim 1, and may further comprise the steps:
S
21, the charging of described frequency converter;
S
22, wait for one second Preset Time after, disconnect described power frequency by-pass switch;
S
23, wait for one the 3rd Preset Time after, described frequency converter stops charging and closed described frequency conversion output switch and frequency conversion input switch.
15. power frequency mode as claimed in claim 14 is switched the method for conversion system, it is characterized in that, described the second Preset Time is 4.7 seconds.
16. power frequency mode as claimed in claim 14 is switched the method for conversion system, it is characterized in that, described the 3rd Preset Time is 0.3 second.
17. power frequency mode as claimed in claim 14 is switched the method for conversion system, it is characterized in that, described frequency conversion power frequency switching device shifter also comprises a differential protection unit, and at step S
23In also comprise lower step: the motor of described differential protection unit and described primary air fan disconnects.
18. the method for the conversion system switching power frequency mode of the motor of primary air fan is characterized in that, uses frequency conversion power frequency switching device shifter as claimed in claim 5, and may further comprise the steps:
S
31, described DCS control system detects described frequency converter and whether sent heavy fault-signal, if then enter step S
32, otherwise repeating step S
31
S
32, disconnect described frequency conversion output switch and frequency conversion input switch;
S
33, wait for one the 4th Preset Time after, closed described power frequency by-pass switch.
19. power frequency mode as claimed in claim 18 is switched the method for conversion system, it is characterized in that, described the 4th Preset Time is 3 seconds.
20. power frequency mode as claimed in claim 18 is switched the method for conversion system, it is characterized in that, described DCS control system also is used for the baffle plate of the described primary air fan of regulating and controlling, and at step S
33Also comprise afterwards lower step:
Described DCS control system is regulated the baffle plate of described primary air fan according to the operating state of a boiler that uses described primary air fan.
21. conversion system as claimed in claim 18 switches the method for power frequency mode, it is characterized in that described frequency conversion power frequency switching device shifter also comprises a differential protection unit, and at step S
33In also comprise lower step: described differential protection unit accesses the motor of described primary air fan.
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| CN2012103042153A CN103051282A (en) | 2012-08-23 | 2012-08-23 | Variable-frequency and industrial frequency switching device and switching method of Variable-frequency and industrial frequency switching device |
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| CN2012103042153A CN103051282A (en) | 2012-08-23 | 2012-08-23 | Variable-frequency and industrial frequency switching device and switching method of Variable-frequency and industrial frequency switching device |
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103516291A (en) * | 2013-09-25 | 2014-01-15 | 无锡阿比利德电力科技有限公司 | Motor power frequency/frequency conversion automatic switching device |
| CN103825509A (en) * | 2014-01-24 | 2014-05-28 | 宁波钢铁有限公司 | Device applied to startup and operation of high-power motors |
| CN105490616A (en) * | 2016-01-11 | 2016-04-13 | 宁波中金石化有限公司 | Circuit structure for boiler blower capable of automatically switching to power frequency from variable frequency |
| CN107959442A (en) * | 2017-11-29 | 2018-04-24 | 武汉纺织大学 | A kind of human action data management system |
| WO2018076128A1 (en) * | 2016-10-28 | 2018-05-03 | 中国电建集团山东电力建设第一工程有限公司 | Test scheme for automatically switching from variable frequency to power frequency for primary draught fan in large unit |
| CN108266398A (en) * | 2017-01-03 | 2018-07-10 | 新疆知信科技有限公司 | Stable operation method during primary air fan frequency conversion cut frequency |
| CN110277948A (en) * | 2019-06-19 | 2019-09-24 | 重庆红岩建设机械制造有限责任公司 | A kind of bridge inspection car VF to WF control system and method |
| CN110601140A (en) * | 2019-06-03 | 2019-12-20 | 史栓保 | Differential protection device and algorithm of variable frequency motor |
| CN111490538A (en) * | 2020-04-23 | 2020-08-04 | 西安热工研究院有限公司 | Accident switching method suitable for primary air fan frequency conversion/power frequency switching system |
| CN112615571A (en) * | 2020-12-08 | 2021-04-06 | 西安热工研究院有限公司 | Frequency conversion and power frequency switching control method for induced draft fan of garbage power plant |
| CN116241446A (en) * | 2023-03-16 | 2023-06-09 | 杰瑞石油天然气工程有限公司 | Compressor control method and compressor unit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103516291A (en) * | 2013-09-25 | 2014-01-15 | 无锡阿比利德电力科技有限公司 | Motor power frequency/frequency conversion automatic switching device |
| CN103825509A (en) * | 2014-01-24 | 2014-05-28 | 宁波钢铁有限公司 | Device applied to startup and operation of high-power motors |
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| CN110277948A (en) * | 2019-06-19 | 2019-09-24 | 重庆红岩建设机械制造有限责任公司 | A kind of bridge inspection car VF to WF control system and method |
| CN110277948B (en) * | 2019-06-19 | 2021-01-19 | 重庆红岩建设机械制造有限责任公司 | Bridge maintenance vehicle frequency conversion to power frequency control system and method |
| CN111490538A (en) * | 2020-04-23 | 2020-08-04 | 西安热工研究院有限公司 | Accident switching method suitable for primary air fan frequency conversion/power frequency switching system |
| CN112615571A (en) * | 2020-12-08 | 2021-04-06 | 西安热工研究院有限公司 | Frequency conversion and power frequency switching control method for induced draft fan of garbage power plant |
| CN116241446A (en) * | 2023-03-16 | 2023-06-09 | 杰瑞石油天然气工程有限公司 | Compressor control method and compressor unit |
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