CN114944640A

CN114944640A - Primary air fan frequency converter fault frequency conversion automatic switching method and device

Info

Publication number: CN114944640A
Application number: CN202210542035.2A
Authority: CN
Inventors: 黄碧怡; 荆鑫; 程凯; 房东贤; 周伟
Original assignee: Huaneng Jinan Huangtai Power Generation Co Ltd
Current assignee: Huaneng Jinan Huangtai Power Generation Co Ltd
Priority date: 2022-05-18
Filing date: 2022-05-18
Publication date: 2022-08-26

Abstract

The utility model provides a primary air fan frequency converter fault frequency conversion automatic switching method and a device, which utilizes DCS logic control to design a plurality of logic controls, obtains the fault signal of the primary air fan frequency converter and sends out the alarm signal of the frequency converter fault; receiving a fault signal of a primary fan frequency converter, starting DCS control logic, and controlling an outlet of the frequency converter to jump off a main switch at the 6KV side; receiving a switch position-division feedback signal at the 6KV side, carrying out frequency conversion and automatic switching of power frequency, and simultaneously tracking the pressure and the temperature in the hearth in real time to carry out real-time detection on the pressure and the temperature.

Description

Primary air fan frequency converter fault frequency conversion automatic switching method and device

Technical Field

The disclosure relates to the technical field of frequency conversion switching, in particular to a method and a device for automatically switching fault frequency conversion of a fan frequency converter.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

The frequency converter is a power control device for controlling an alternating current motor by applying a frequency conversion technology and a microelectronic technology and changing the frequency mode of a working power supply of the motor, and mainly comprises a rectification unit (alternating current to direct current), a filtering unit, an inversion unit (direct current to alternating current), a braking unit, a driving unit, a detection unit and a microprocessing unit and the like.

The frequency converter adjusts the voltage and frequency of an output power supply by switching on and off the internal IGBT, and provides the required power supply voltage according to the actual requirement of the motor, thereby achieving the purposes of energy conservation and speed regulation.

The power frequency is the rated frequency of electrical equipment in an electric power system, generally 50hz, the frequency conversion is to reduce the frequency of the alternating current power supply, and the square of the frequency is in direct proportion to the output power, so that the use power of the electrical equipment can be effectively reduced after the frequency conversion technology is adopted, and the purposes of energy conservation and consumption reduction are achieved.

In a thermal power plant, some important loads, such as primary fans and other important auxiliary equipment, have large capacity and high power consumption, and are in a continuous operation, low-load and variable-load state for a long time, the energy consumption can be reduced by reducing the frequency, and the generated economic benefit is very considerable, so that a mode of additionally installing a frequency converter is often adopted on site to reduce the energy consumption of a motor, and the effects of reducing the plant power consumption rate, automatically controlling the pressure of a hearth, stabilizing and the like are achieved The device is huge, the probability of successful rescue is less than 10%, the unit unplanned shutdown caused by the frequency converter failure is realized, the single check economic indicator reaches more than one million yuan, the consequence of shutdown of the primary fan caused by the frequency converter failure is very serious, the primary fan needs to be switched to a power frequency operation state from a frequency conversion state when the frequency converter is suddenly in an important failure, generally, in the process of switching the frequency conversion state, the amplitude of air volume change is large during switching in the prior art, the combustion stability of a boiler is influenced, and thus, the non-shutdown accident is caused by overlarge furnace pressure and air volume change, and the safety and stability of power production are influenced.

Disclosure of Invention

The invention provides a method and a device for automatically switching primary fan frequency converter fault frequency conversion, and provides multiple variable switching logic, which ensures that automatic switching is carried out only when the frequency converter has a fault, and the variable switching logic is used as backup protection for the fault of the frequency converter, so that a unit is prevented from directly stopping a boiler and stopping the boiler when the frequency converter has a fault.

According to some embodiments, the following technical scheme is adopted in the disclosure:

a primary air fan frequency converter fault frequency conversion automatic switching method comprises the following steps:

acquiring the running state of a primary air fan frequency converter in real time, acquiring a fault signal of the primary air fan frequency converter and sending a frequency converter fault alarm signal;

receiving a fault signal of a primary fan frequency converter, starting DCS control logic, and controlling an outlet of the frequency converter to jump off a main switch at the 6KV side;

receiving a 6KV side switch split-position feedback signal, and carrying out frequency conversion and automatic power frequency switching;

and in the switching process, tracking the running state of the hearth in real time, and acquiring normal signals of the pressure and the temperature in the furnace, otherwise, immediately entering an RB logic state to rescue the unit.

Further, during switching, the DCS controls to jump off the high-voltage main switch at the 6kV side, then jumps off the first contactor of the input contactor at the converter side and the second contactor of the output contactor at the converter side, sets a time period, firstly closes the third contactor of the power frequency input contactor, and then closes the main switch at the 6kV side to complete electrical switching.

According to other embodiments, the present disclosure also adopts the following technical solutions:

the utility model provides a primary air fan converter trouble frequency conversion automatic switching control equipment, includes:

the frequency converter is used for controlling power control equipment of the alternating current motor and mainly comprises a rectifying unit, a filtering unit, an inverting unit, a braking unit, a driving unit and a detecting unit micro-processing unit;

the sensor is used for acquiring the running state of the primary air fan frequency converter in real time, acquiring a fault signal of the primary air fan frequency converter and sending a frequency converter fault alarm signal;

the DCS control system is used for receiving fault signals of the primary fan frequency converter, starting DCS control logic, controlling an outlet of the frequency converter to jump on a main switch at the 6KV side and receiving a switch position division feedback signal at the 6KV side, and carrying out frequency conversion and automatic power frequency switching;

and the contactor is used for closing a switch in the frequency conversion power frequency switching logic control.

Still include circuit breaker and motor, the circuit breaker realizes the frequency conversion and cuts the arc extinguishing of power frequency in-process, whole power system's operation is realized to the motor.

Compared with the prior art, the beneficial effect of this disclosure is:

the design of primary air fan frequency converter changing switching logic is under logic control under various conditions, when the frequency converter device fails, the switching logic is realized, the fire extinguishing accident of the MFT boiler of the unit is prevented, the stable operation of a power system is maintained, and the influence caused by non-stop accidents is reduced and avoided.

DCS control carries out effectual observation to switching process, tracks indexes such as furnace wind temperature, wind pressure, burning situation in real time, and effectual realization monitors unit operating condition to the deciliter control of high tension apparatus switch, simultaneously, and after the frequency conversion switched to the power frequency, when the fan output increases suddenly, avoided causing furnace detonation, influence the problem of unit safe operation.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure.

FIG. 1 is a schematic diagram of a DCS control system of the present disclosure;

FIG. 2 is a block diagram of electrical switching logic of the present disclosure;

FIG. 3 is a schematic diagram of the primary air fan frequency converter fault frequency conversion automatic switching power frequency logic of the present disclosure;

FIG. 4 is a frequency conversion switching power frequency failure starting RB logic diagram of the present disclosure;

FIG. 5 is a schematic diagram illustrating the primary fan outlet gate adjustment operation logic after the primary fan frequency conversion switches the power frequency according to the present disclosure;

FIG. 6 is a schematic diagram of a control logic of a primary air fan 6KV side switch according to the present disclosure;

the specific implementation mode is as follows:

the present disclosure is further described with reference to the following drawings and examples.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

Example 1

In a thermal power plant, some important loads, such as primary fans and other important auxiliary equipment, have large capacity and high power consumption, and are in a continuous operation, low-load and variable-load state for a long time, the energy consumption can be reduced by reducing the frequency, and the generated economic benefit is very considerable. Therefore, the mode of additionally installing a frequency converter is often adopted on the spot, the energy consumption of the motor is reduced, and the effects of reducing the plant power consumption, automatically controlling the pressure of the hearth, being stable and the like are achieved.

Because these important auxiliary machines often are the high-voltage electrical equipment of more than 6kV, and domestic high-voltage frequency conversion technique is limited, the condition that the converter various faults appear in service occasionally takes place.

Taking the primary air fan frequency converter of our factory as an example, under the normal condition, the primary air fan is operated in a frequency conversion mode, once the frequency converter trips due to faults, the unit immediately gets rid of the load by 50%, and meanwhile, the unit enters the RB state to rescue the unit. However, because the primary fan is an important auxiliary machine, the number of systems and devices which need to be rapidly adjusted is large, and the probability of successful rescue is less than 10%. The unplanned shutdown of the unit caused by the failure of the frequency converter is checked once, and the economic index of the factory reaches more than one million yuan, so that the shutdown of the primary fan caused by the failure of the frequency converter is prevented, and the method is particularly important.

The utility model provides a primary air fan frequency converter fault frequency conversion automatic switching method, which executes the following steps:

In specific implementation, how to switch the primary fan from a frequency conversion state to a power frequency state as undisturbed as possible when the frequency conversion device fails, we think that a variable switching device can be added in a bypass system of the frequency converter, and simultaneously a set of automatic air volume adjusting logic in the variable switching process is designed in a DCS system, so that in the switching process, the process of switching the primary fan motor with the minimum disturbance of the furnace pressure is completed.

In the operation of a primary air fan, when the frequency converter breaks down, how to switch the frequency converter to the power frequency state by the frequency conversion state, can divide several stages or several circumstances into consideration:

when to perform switching, switching conditions, how to realize switching, how to ensure reliable switching, what special conditions need to be avoided, what to do after switching failure and how to adjust a unit after switching, considering the above problems, designing logic control for various problems, and adopting an effective method to overcome the difficulties in the above problems.

(1) When to make automatic switching

Because the frequency conversion power frequency switching has risks, the motor is possibly damaged, and the normal operation of the unit is influenced, the frequency conversion power frequency switching logic ensures that automatic switching is carried out only when the frequency converter fails, and the frequency conversion power frequency switching logic is used as backup protection for the frequency converter failure, so that the unit is prevented from being shut down due to direct boiler fire stopping when the frequency converter fails.

(2) How to implement handover

Because two modes are considered, one is PLC control of the frequency converter, and the other is DCS control. Because PLC control can not carry out effectual observation to the switching process, can not track index such as furnace wind temperature, wind pressure, burning situation in real time to PLC's deciliter control to high tension apparatus switch is unreliable, can't detect unit operating condition, consequently becomes that the cutter automatic switch-over success rate is not high.

2. The method for automatically switching the power frequency by adopting the DCS control mode is designed, during switching, the DCS control trips off a high-voltage main switch at the 6kV side, then trips off a first contactor of an input contactor at the converter side and a second contactor of an output contactor at the converter side, a time period is set, a third contactor of the input contactor at the power frequency is closed firstly, then the main switch at the 6kV side is closed, and electrical switching is completed.

Specifically, in fig. 1, when the frequency converter has a heavy fault or is stopped, the frequency converter is controlled by the DCS, the high-voltage main switch on the 6kV side is tripped, then the input contactor KM1 on the frequency converter side and the output contactor KM2 on the frequency converter side are tripped, the power frequency input contactor KM3 is turned on after a short time delay, and finally the main switch on the 6kV side is turned on, so that the electrical switching is completed. In the period, the DCS device tracks the running state of the hearth, and immediately enters the RB state once overpressure or deflagration occurs in the furnace, so that the unit is rescued.

Time analysis of a specific time delay 6KV side switch: after the frequency converter is tripped due to a fault, the DCS controls the time for receiving the position division feedback signal of the 6KV side switch to have inherent delay of 200ms, the time for judging and opening the contactor at the outlet is 1s, the time for receiving the position combination feedback signal of the power frequency side contactor is 200ms, the demagnetization time of the motor is calculated in a setting mode to be 2-3s, and then the 6KV side switch is combined with the delay of 1 s. And the automatic frequency conversion power frequency switching logic switching time is controlled within 5 s.

(3) How to guarantee reliable handover

And setting various logics to control and realize safe switching.

In the switching process, a 6KV side switch needs to be protected, if the 6KV side switch is not tripped due to the fault of a frequency converter, the 6KV side switch can be subjected to secondary impact on a power utilization system of the 6KV side switch after automatic switching, a NOT gate of the 6KV side switch for protection action is added into the switching starting logic, and namely the frequency-switching power frequency logic is not started when the 6KV side switch is subjected to protection action.

When the unit is shut down, the frequency conversion switching frequency logic control is caused in the process of the frequency converter maintenance test, an MFT boiler fire-extinguishing protection reset signal is added into the switching start logic, and when the reset signal is detected, the frequency conversion switching frequency logic is controlled not to be started in a shutdown state.

When the frequency converter is started, if the frequency converter is not started, fault tripping occurs, the position of the frequency converter cannot be determined, and the frequency converter cannot be put into operation, a frequency conversion switching power frequency manual input button is added into a switching starting logic, so that the frequency converter is ensured to be manually input after being normally started.

If the frequency conversion power frequency switching logic is executed circularly and the 6KV side switch is switched on and off for multiple times due to the occurrence of the condition, the frequency conversion power frequency switching execution is automatically quitted after the frequency conversion power frequency switching starting logic starts, and the automatic switching logic is ensured to be executed only once.

The switching process is refined, and the equipment and the flow involved in the switching are analyzed:

1. action behaviors of the contactor and the breaker: because the fault switching of the voltage level of 6kV or above is involved, the arc extinguishing capability of the contactor and the breaker needs to be considered, obviously, the arc extinguishing capability of the contactor is far inferior to that of the high-voltage breaker, and therefore the high-voltage breaker is used for arc extinguishing in the whole switching process. When the frequency converter breaks down, the frequency converter sends out a heavy fault alarm signal and simultaneously can exit and trip off a main switch at the 6kV side, at the moment, the design is needed to ensure that the electrical switching process is carried out after a switch position division signal is received, otherwise, the burning and the failure of a secondary device can be caused by arc extinguishing overvoltage and heavy current. Similarly, because the power frequency contactor does not have the arc breaking capability, the main switch at the 6kV side needs to be closed after the power frequency contactor KM3 is closed in the closing process, and the main switch at the 6kV side is used for arc extinction.

2. Protection of the motor: when the three-phase motor normally runs, the main magnetic field rotating at the synchronous rotating speed induces symmetrical three-phase electromotive force in the three-phase winding of the stator. If the power supply is disconnected, the main magnetic field disappears, but the residual magnetism still exists in the rotor iron core which is magnetized by the main magnetic field, meanwhile, the rotor still rotates at a high speed due to inertia, and the induced electromotive force generated in the stator coil does not disappear in a very short time, but is attenuated. Therefore, in the switching process, the residual magnetism needs to be reduced for as long as possible while the pressure in the furnace is ensured, so that the large voltage difference delta U generated when the power frequency voltage is put into use is prevented from impacting the motor, and the motor is further damaged. However, the long time means that the unilateral primary air pressure is greatly reduced, and the long time triggers the fire extinguishing logic of the boiler of the unit, so that the shutdown of the unit is caused, which is equivalent to the expansion of accidents.

The condition is tested and analyzed, after the frequency converter trips due to faults, the DCS receives a position division feedback signal of the 6kV side switch, inherent delay time is about 200ms, the time for logically judging and exiting the tripping contactor is about 1s, the time for receiving a position closing feedback signal of the power frequency side contactor is about 200ms, and demagnetization time of the motor is calculated in a setting mode to be 2-3s, so that the fact that the 6kV side switch is additionally delayed and closed for 1s is reasonable on the basis.

3. Protection of primary air pressure of the unit: a large amount of data are inquired, a machine set is tested by using a start-stop machine opportunity, in order to stabilize combustion and prevent the machine set from stopping operation caused by too much primary air pressure reduction, and the logic switching time of automatic switching is controlled within 5s through calculation.

(4) Special cases to be avoided

In addition to the above normal handover procedure, we consider various special cases and design the relevant logic to avoid these problems.

The 1.6kV side switch is not tripped due to the fault of a frequency converter, but the fault of a cable, a motor or a switch causes the tripping of the switch, and at the moment, if the automatic switching is carried out, the impact can be caused to the 6kV side switch and even an auxiliary power system. In order to avoid the situation, a NOT gate of a 6kV side switch protection action is added in a switching starting logic, namely, switching is not carried out when the 6kV side switch protection action is carried out, and secondary impact on a station power system is guaranteed not to be carried out.

2. In order to prevent error switching of variable switching logic in the process of a frequency converter overhaul test when a unit is stopped, an MFT boiler fire extinguishing protection reset signal is added into switching start logic, and therefore the variable switching logic is guaranteed not to be started in a stop state.

3. When the converter starts, if the converter does not start and just trips because of the fault, the direct switching power frequency is unfavorable for finding out the converter position fast this moment, is unfavorable for the converter to put into operation. Therefore, a manual switching button of a switching worker is added into the switching starting logic, and operators manually switch on and off, so that the frequency converter is enabled to be manually switched on again after being normally started, and the unit is enabled to safely operate.

4. In order to prevent a switch on/off state of a 6kV side switch from being repeatedly switched on and off to damage primary equipment due to cyclic execution of a switch-on/off logic caused by special conditions, a switch-off execution button is automatically withdrawn after the switch-on/off logic of a switch is started, and the automatic switching working condition is guaranteed to be performed only once.

(5) How the switching fails

The whole switching process relates to various operation loops of a plurality of switches, certain possibility of switching failure exists, if the RB logic of the unit is not started after the failure of the variable-speed switching operation, the primary air pressure is further reduced, and finally the unit is stopped.

In order to avoid the situation, the RB logic is started to be optimized after the primary fan variable switching logic execution fails, and when the primary fan is switched to a power frequency state and a high-voltage switch on the 6kV side trips, the RB function of the unit is triggered in a delayed mode; or after the execution of the variable switching logic is finished, the switch on the 6kV side can not be switched on within 5s, and the unit automatically enters the RB logic to be rescued.

(6) How a unit adjusts after the logic switching of the variable switch

After the power frequency is cut at the converter, because under the power frequency state, the frequency reaches the primary air fan behind the rated power and exerts an increase suddenly, can cause the interior wind pressure of furnace to increase suddenly, arouses that the wind pressure is undulant, still can make the fuel volume that gets into furnace increase suddenly simultaneously, the combustion aggravation, this can cause unit over heater overtemperature, superpressure, because the wind pressure increase leads to sending into furnace's fuel increase even, destroy the configuration of wind-coal ratio, cause the burning incomplete and threaten unit safety.

Therefore, in the process of switching the switching logic, the matching problem of switching the frequency converter and adjusting the baffle is also considered. And the action characteristic difference of the frequency converter and the baffle, the frequency converter is not provided with the baffle on the speed regulation, and the frequency converter is easy to cause overcurrent tripping in the quick action, thereby threatening the safety of the unit. In order to avoid the situation, the action situation of a primary fan movable blade baffle in the switching process is logically designed by combining with the thermal engineering specialty. The outlet door is controlled according to the wind pressure, the wind volume, the temperature and the combustion condition in the hearth, so that the combustion stability in the hearth is ensured.

Example 2

The utility model provides a primary air fan converter trouble frequency conversion automatic switching control equipment includes:

the DCG control system is used for receiving a fault signal of the primary fan frequency converter, starting DCS control logic, controlling an outlet of the frequency converter to jump on a main switch at the 6KV side and receiving a switch position division feedback signal at the 6KV side, and carrying out frequency conversion and automatic power frequency switching;

Still include circuit breaker and motor, the circuit breaker realizes the frequency conversion and cuts the arc extinguishing of power frequency in-process, whole power system's operation is realized to the motor. The above devices are connected to communicate with each other, so as to realize signal transmission.

The method specifically comprises the following steps:

During switching, the DCS controls to trip off the high-voltage main switch at the 6kV side, then trips off the first contactor of the input contactor at the side of the frequency converter and the second contactor of the output contactor at the side of the frequency converter, a time period is set, the third contactor of the power frequency input contactor is closed firstly, then the main switch at the 6kV side is closed, and electrical switching is completed.

In the switching process, a 6KV side switch needs to be protected, if the 6KV side switch is not tripped due to the fault of a frequency converter, secondary impact can be carried out on an electric system of the 6KV side switch by carrying out automatic switching, a not-gate of the 6KV side switch for protection action is added into switching starting logic, namely, the frequency-switching power frequency logic is not started when the 6KV side switch is in protection action.

When each part is logically controlled: when the frequency conversion input switches k1 and k2 are in the on-position, the 6kv switch is switched on, and the primary fan motor operates in a frequency conversion mode. When k1 and k2 are in a separated position, and after the k3 contactor is closed, the 6kv switch is closed, and the primary fan motor operates at power frequency.

The primary fan changes the switching logic as follows: when a primary fan frequency converter has a heavy fault needing frequency conversion tripping, the frequency converter trips to open a 6kv switch (6kv switch is separated), the unit air volume does not reach a fixed value (MFT reset signal) of the MFT for starting boiler fire extinguishing, and a switching function button is switched on (automatic switching input), and a primary fan motor normally operates, the 6kv protection device does not act (the primary fan does not have a protection action signal), when the above conditions are all satisfied, the DCS sends out instructions of the input switches KM1 and KM2 of the primary fan frequency converter, in order to ensure the orderly tripping of the switch, the reverse power transmission caused by the simultaneous opening and closing of the switch is prevented, after the tripping instructions of the KM1 and KM2 are sent out, the time is delayed for 2 seconds, the DCS sends out an instruction of switching of the KM3, and the power frequency output switch KM3 of the primary fan. When the logic is completely executed and the KM3 switch is closed (the power frequency output switch KM3 of the primary fan frequency converter is closed), the DCS sends a primary fan 6KV switch instruction, the 6KV switch is closed, and the primary fan motor is operated at the working frequency.

The primary fan fault automatic power frequency switching DCS configuration logic is as follows: when a fan frequency converter has a heavy fault (heavy fault of a primary fan frequency converter) which needs to trip the frequency converter, the frequency converter trips, namely, 6kv switch is switched off (the primary fan frequency converter stops), the unit air volume does not reach a fixed value (MFT does not act) for starting a boiler to extinguish a fire, and a variable-switching function button is switched on (variable-switching-off input), the air volume in a wind-smoke system meets the operation requirement, the primary fan thermal protection does not act (primary fan protection does not act), the primary fan motor is normal, a 6kv protection device does not act (primary fan tripping is reversed), when the above conditions are met, the DCS sends out a primary fan frequency converter tripping input switch KM1 and a KM2 instruction (primary fan frequency conversion input switches KM1 and KM2), in order to ensure the orderly tripping of the switch and prevent the reverse power transmission caused by the simultaneous opening and closing of the switch, the KM1 and KM2 tripping instruction is delayed for 2 seconds, and the DCS sends out a 3 switching-on instruction, and (5) switching on a power frequency output switch KM3 of the primary fan, and starting the primary fan to change the working condition of the primary fan. When all the logics are executed, and after the KM3 switch is closed (the power frequency output switch KM3 of the primary fan frequency converter is closed, and the KM3 switch is in two positions), the DCS sends a 6KV switch instruction of the primary fan, the 6kV switch is closed, and the primary fan motor is operated in a power frequency conversion mode.

After the KM3 closing time is over (KM3 position signals 1, 2 and 3, two out of three are delayed for 3 seconds), and 6KV switch opening position (the primary fan stops for three and two out), namely 6KV switch closing failure, or 6KV switch closing failure (the primary fan stops for three and two out of three) is delayed for 5 seconds, the unit RB condition is started.

In order to ensure the safe operation of the unit, the primary fan frequency converter logic can be executed only once. Therefore, the maximum time of 10s is needed after the execution of the logic is finished through field tests, and once the variable cutting logic is started, the variable cutting execution logic block is automatically cut after the delay of 10s +5s (the variable cutting is automatically cut).

The process of starting the RB after the switching failure is changed is as follows: when the power frequency output switch KM3 of the primary fan frequency converter is in on position, and is separated from the 6kv switch (namely 6kv switching-on failure) after 2s of time delay (ensuring KM3 reliable switching-on time), the RB logic of the unit is started. Or tripping or failing to close the switch (the primary fan 6kV switch is in a dislocation state) for 5s due to other reasons of the 6kV switch, and starting the unit RB.

When the variable switching logic is successfully executed, the primary fan 6kV switch is switched on again, after the primary fan motor runs at full speed, the furnace chamber is stably combusted, and the DCS cuts off the control logic of the frequency converter and changes the control logic into the automatic/manual control logic of the primary air baffle.

Taking the primary fan switching as an example, after 8s of time delay, the SFT baffle specified position adjusting logic block is started. Z is set to 1 in the SFT logic block, forcing the output of the X1 shutter position 80% command. To the X2 pin of the next SFT logic block. The point 103/61 is that the change-over failure triggers the RB logic block, which is 0 at this time, so the SFT logic block continues to output an 80% opening instruction to the ES/MA logic block OV override forced-open pin, and therefore, after the change-over is completed, the primary fan baffle position forces to output 80% opening. In the ES/MA logic block, the priority of OV pin is higher than the automatic control priority of X pin.

Therefore, after the cutting process is finished, the baffle position of the primary fan is forced to be opened to 80 percent. When the hearth is stably combusted, an operator can automatically switch the baffle input into a manual control mode, at the moment, OV instruction priority is cut off from the ES/MA logic block, and the ES/MA inputs baffle automatic control priority (5-0) of the X pin. And entering an RATL logic block for difference adjustment operation according to the current primary air pressure and a primary air pressure set value set by an operator, and entering DEW correction logic blocks according to the operation result. And after difference (power frequency) correction is carried out on the difference with the primary wind pressure deviation in the power frequency state, the difference enters a Z1 pin in the QORS operation logic block. The QOR8 logic block converts the primary wind pressure differential to a damper opening metric according to a PID algorithm. The damper opening degree regulating quantity is input into TOM pin of ES/MA logic block, finally the ES/MA outputs primary air damper instruction. Thereby achieving the purposes of stable combustion of the hearth and manual air quantity regulation.

For the 6kV side switch start-stop control logic, DCS adopts DEVICE module control. When the variable switching logic acts, an override 6kV switch instruction is sent out (the variable switching overrides the 6kV switch), and the primary fan does not have a protection action trip and a fault signal, the device module executes Emd1 to output a forced switching instruction, namely out1, and outputs a 6kV switch switching-on instruction. When the smoke temperature of the primary air fan, the opening degree of the baffle and the operation condition of the auxiliary machine meet the starting permission condition of the primary air fan, the pin D1p is arranged at 1, a switch-on permission signal is sent out in an operation interface, and the primary air fan is allowed to start a 6kv switch. When the primary air fan frequency converter stops sending the opening signal, after 10 seconds of free stop delay, D2P in the device module sends the closing permission instruction, the opening in the operation interface is permitted to send, and the primary air fan is allowed to stop 6 kv.

The primary air fan running signal is fed back to FB1 (starting feedback signal) to set 1, and the device feeds back the primary air fan running state. The primary air fan stop signal is fed back to FB2 (stop feedback signal) set to be 1, and the device feeds back the primary air fan stop state. The remote local state of the primary fan is input into a device module LOC (local area network) by taking the inverse, when the input result is 1, the control mode of the primary fan is judged to be remote, and the DCS is allowed to send a start-stop instruction to a 6kV switch of the primary fan. The LPWR pin in the Device module reflects a light fault state or a heavy fault state of the primary fan frequency converter, and once the frequency converter is in the fault state, the Device module locks the primary fan on/off instruction output. Similarly, the primary fan protection action signal is connected to the device module fault pin. Namely 6kv protection device action, and the device module starting instruction is locked. And (3) tripping protection of a side fan, namely, thermal protection is introduced into a DEVICE module totp pin, thermal protection acts, and a DEVICE module is locked, namely, a primary fan starting instruction is locked.

As will be appreciated by one skilled in the art, embodiments of the present disclosure may be provided as a method, system, or computer program product. Accordingly, the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present disclosure may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and so forth) having computer-usable program code embodied therein.

The present disclosure is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the disclosure. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Although the present disclosure has been described with reference to specific embodiments, it should be understood that the scope of the present disclosure is not limited thereto, and those skilled in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the present disclosure.

Claims

1. A primary air fan frequency converter fault frequency conversion automatic switching method is characterized by comprising the following steps:

2. The method of claim 1, wherein during switching, the DCS controls to trip off a high-voltage main switch at the 6kV side, then trip off a first contactor of an input contactor at the converter side and a second contactor of an output contactor at the converter side, set a time period, first switch on a third contactor of an input contactor at the power frequency, and then switch on the main switch at the 6kV side, thereby completing electrical switching.

3. The method for automatically switching the primary air fan frequency converter during fault frequency conversion according to claim 2, wherein the time analysis of a specific delay-in 6KV side switch is as follows: after the frequency converter trips in a fault, the DCS controls the time for receiving a position division feedback signal of the 6KV side switch to have inherent delay of 200ms, the time for judging and outputting the tripping-out contactor is 1s, the time for receiving a position closing feedback signal of the power frequency side contactor is 200ms, the demagnetization time of the motor is calculated in a setting mode to be 2-3s, and then the 1s delay is added to close the 6KV side switch.

4. The method for automatically switching the primary air fan frequency converter during the fault frequency conversion according to claim 1, wherein the power frequency logic switching time of the automatic frequency conversion switch is controlled within 5 s.

5. The method for automatically switching the frequency converter of the primary fan through the fault frequency conversion is characterized in that a 6KV side switch is protected in the switching process, if the 6KV side switch is not tripped due to the fault of the frequency converter, secondary impact is carried out on a power utilization system of the 6KV side switch through automatic switching, a not-gate of the 6KV side switch for protection action is added into switching starting logic, and therefore the frequency conversion power frequency logic is not started when the 6KV side switch is in protection action.

6. The method for automatically switching the primary fan frequency converter fault frequency conversion according to claim 1, characterized in that when a unit is shut down, frequency conversion switching frequency logic control is caused in a frequency converter maintenance test process, an MFT boiler fire extinguishing protection reset signal is added into switching start logic, and when the reset signal is detected, the frequency conversion switching frequency logic is controlled not to be started in a shutdown state.

7. The method for automatically switching the primary fan frequency converter during the fault frequency conversion according to claim 1, wherein when the frequency converter is started, if the frequency converter is not started, a fault trip occurs, the position of the frequency converter cannot be determined, and the frequency converter cannot be put into operation, a frequency conversion power frequency switching manual input button is added into switching starting logic to ensure that the frequency converter is put into operation again manually after being started normally.

8. The method for automatically switching between the fault frequency conversion and the frequency conversion of the primary air fan frequency converter according to claim 1, wherein if the fault frequency conversion and the frequency conversion switching are circularly executed due to the occurrence condition, and a switch on the 6KV side is switched on and off for multiple times, the fault frequency conversion and the frequency conversion switching are automatically quitted after the start of the fault frequency conversion and the frequency conversion starting logic, so that the automatic switching logic is only executed once.

9. The utility model provides a primary air fan converter trouble frequency conversion automatic switching control equipment which characterized in that includes:

10. The device of claim 9, further comprising a circuit breaker and a motor, wherein the circuit breaker is used for arc extinction during the frequency conversion and power frequency switching process, and the motor is used for operation of the whole power system.