Frequency conversion starting control system of flue gas auxiliary steam oil displacement integrated equipment

Abstract

The invention discloses a variable-frequency starting control system for flue gas auxiliary steam oil displacement integrated equipment, which comprises a three-phase power supply, a first motor, a second motor and a frequency converter, and is characterized in that the input end of the frequency converter is connected with the output end of the three-phase power supply through a first circuit breaker; the output end of the frequency converter is connected with the first motor and the second motor through a second contactor and a fourth contactor respectively; a first contactor is connected in parallel between the input end of the first circuit breaker and the output end of the second contactor; a third contactor is connected in parallel between the input end of the first circuit breaker and the output end of the fourth contactor; the control end of the frequency converter controls on-off of the first contactor, the second contactor, the third contactor and the fourth contactor through a secondary side control loop. According to the invention, a mode that the frequency converter drives two electric devices is adopted, automatic switching control of double motors between frequency conversion starting and power frequency operation is realized through the secondary side control loop, the economical efficiency and the stability of system operation are effectively improved, and the fault risk is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and more specifically, to a variable frequency starting control system for flue gas assisted steam oil recovery integrated equipment. Background Art

[0002] Heavy oil is an important component of crude oil production in my country, and steam injection thermal recovery is the main technology for heavy oil development. However, during the steam injection thermal recovery process, the flue gas generated by boiler combustion is usually discharged directly into the atmosphere, forming "carbon pollution". The flue gas assisted steam flooding integrated equipment uses the dual mechanisms of nitrogen injection expansion energy enhancement and carbon dioxide injection dissolution and viscosity reduction, which can effectively assist in improving the fluidity of heavy oil and realize steam thermal recovery and flue gas mixed flooding. This highly integrated, low-energy consumption, mobile operation boosting equipment can better meet the needs of green development of oil fields and improve quality and efficiency.

[0003] At present, flue gas-assisted steam oil recovery integrated equipment is mostly composed of a set of screw compressors and a set of reciprocating compressors independently configured in series. The main motors of the two compressors have large power. If two sets of inverters are configured, it will not only increase the operating cost, but also there is a risk of inverter switching failure, leading to the risk of safety accidents.

[0004] In order to solve the above problems, it is necessary to design a variable frequency starting control system for flue gas assisted steam oil recovery integrated equipment to save costs while ensuring the efficient and stable operation of the boosting equipment. Summary of the invention

[0005] The purpose of the present invention is to provide a variable frequency starting and control system for integrated equipment of flue gas assisted steam oil recovery, which adopts the mode of one frequency converter to drive two electrical equipments, and at the same time configures a standby bypass for the motor of each electrical equipment, and realizes automatic switching control between variable frequency starting and industrial frequency operation of the dual motors through the secondary side control loop, which effectively improves the economy and stability of the system operation and reduces the risk of failure.

[0006] In order to achieve these purposes and other advantages according to the present invention, a variable frequency starting control system for flue gas assisted steam oil recovery integrated equipment is provided, comprising a three-phase power supply, a first motor, a second motor and a frequency converter; The input end of the frequency converter is connected to the output end of the three-phase power supply via a first circuit breaker, and the output end of the frequency converter is connected to the first motor and the second motor via a second contactor and a fourth contactor respectively; A first contactor is connected in parallel between the input end of the first circuit breaker and the output end of the second contactor, the input end of which is connected to the output end of the three-phase power supply via the second circuit breaker, and the output end of the first contactor is connected to the first motor; A third contactor is connected in parallel between the input end of the first circuit breaker and the output end of the fourth contactor, the input end of which is connected to the output end of the three-phase power supply via the third circuit breaker, and the output end of the third contactor is connected to the second motor; The control end of the frequency converter controls the on and off of the first contactor, the second contactor, the third contactor and the fourth contactor through a secondary side control loop.

[0007] Preferably, in the variable frequency starting control system of the flue gas assisted steam flooding integrated equipment, the secondary side control circuit includes multiple circuits, each circuit is powered by the same control power supply, and the multiple circuits include a main control circuit, and the control method is to control and switch the on-off status of each contactor according to the operating state of the inverter, including: When the first motor needs to be started by frequency conversion, the second contactor is controlled to be closed, and the first circuit breaker is closed at the same time, so that the output voltage of the three-phase power supply is supplied to the first motor after being processed by the frequency converter; when the first motor is started, the control end of the frequency converter outputs a corresponding control signal to control the second contactor to be disconnected and the first contactor to be closed, and the second circuit breaker is closed at the same time, so that the first motor is switched to power frequency operation; When the second motor needs to be started by variable frequency, the fourth contactor is controlled to be closed, and the first circuit breaker is closed at the same time, so that the output voltage of the three-phase power supply is supplied to the second motor after being processed by the frequency converter; after the second motor is started, the control end of the frequency converter outputs a corresponding control signal to control the fourth contactor to be disconnected and the third contactor to be closed, and the third circuit breaker is closed at the same time, so that the second motor switches to industrial frequency operation.

[0008] Preferably, in the frequency conversion starting control system of the flue gas assisted steam oil recovery integrated equipment, in the main control loop, the second contactor is electrically interlocked with the first contactor and the fourth contactor, and the fourth contactor is electrically interlocked with the second contactor and the third contactor.

[0009] Preferably, in the variable frequency starting control system of the flue gas assisted steam oil recovery integrated equipment, there are two control modes, local and remote, in the main control loop, both of which are used to realize the start, stop and switching control of the first motor and the second motor.

[0010] Preferably, the frequency conversion starting control system of the flue gas assisted steam oil recovery integrated equipment, the multiple circuits also include a frequency conversion fault control circuit, the input side of which is sequentially connected in series with the frequency conversion fault signal terminal of the frequency converter and the coil of the frequency conversion fault relay and then output, and the normally closed contact of the frequency conversion fault relay is serially connected in the main control circuit; a frequency conversion fault indication circuit, the input side of which is sequentially connected in series with the normally open contact of the frequency conversion fault relay and the frequency conversion fault indicator light and then output.

[0011] Preferably, the variable frequency starting control system of the flue gas assisted steam oil recovery integrated equipment, the multiple circuits also include an emergency stop control circuit, the input side of which is respectively outputted through an external fault signal terminal, an emergency stop switch and a coil of an emergency stop signal relay connected in series, and the emergency stop signal relay is configured to control the opening of the electric operating mechanism of the control power supply.

[0012] Preferably, the frequency conversion start-up control system of the flue gas assisted steam flooding integrated equipment, the multiple circuits further include: The power indicator circuit has an input side connected to the power indicator light and then output; A first variable frequency start indication circuit, the input side of which is connected to the first variable frequency start indicator light via the normally open contact of the second contactor and then output; A second variable frequency start indication circuit, the input side of which is connected to the second variable frequency start indicator light via the normally open contact of the fourth contactor and then output; A first bypass operation indication circuit, the input side of which is connected to the first bypass operation indicator light via the normally open contact of the first contactor and then output; The second bypass operation indicating circuit has an input side connected to the second bypass operation indicating lamp via the normally open contact of the third contactor and then output.

[0013] Preferably, in the variable frequency starting control system of the flue gas assisted steam oil recovery integrated equipment, the first motor and the second motor need to be reset before the second starting by variable frequency.

[0014] Preferably, in the variable frequency starting control system of the flue gas assisted steam oil recovery integrated equipment, the primary winding of the first current transformer is connected in series between the output end of the first contactor and the first motor, and the secondary winding of the first current transformer is connected to the first thermal relay; the primary winding of the second current transformer is connected in series between the output end of the third contactor and the second motor, and the secondary winding of the second current transformer is connected to the second thermal relay.

[0015] The present invention has at least the following beneficial effects: 1. The present invention uses the hardware main circuit and the secondary side control circuit to jointly control the system working conditions of the inverter with one power-consuming device and two power-consuming devices, and can control the motors of different power-consuming devices to start smoothly and switch to bypass reliably, effectively improving the operation efficiency and safety of the equipment, while reducing the number of starting devices, reducing the design and manufacturing costs and the probability of safety accidents, which is conducive to realizing efficient start-up control and safe and reliable switching of flue gas-assisted steam flooding integrated equipment, ensuring the stable operation of flue gas flooding equipment; 2. The variable frequency starting control system of the present invention can realize the flexible starting of the equipment, reduce the impact of the starting current on the power grid, improve the safety of the power grid operation, and at the same time reduce the energy loss of the motor, further reduce the operating cost, and comprehensively improve the stability and economy of the working system; 3. The variable frequency starting control system of the present invention can be widely used in the field of dual-motor variable frequency starting control, and is not limited to a single flue gas-assisted steam flooding integrated equipment, and has good application prospects.

[0016] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A circuit diagram of a primary side control loop of a variable frequency start-up control system for flue gas assisted steam flooding integrated equipment according to an embodiment of the present invention; Figure 2 It is a circuit diagram of the secondary side control loop of the variable frequency starting control system of the flue gas assisted steam flooding integrated equipment described in the above embodiment; Figure 3 is a circuit diagram of the electric operating mechanism described in the above embodiment; Figure 4 It is a schematic diagram of the external structure of a control cabinet equipped with the variable frequency starting control system of the flue gas assisted steam oil recovery integrated equipment described in the above embodiment. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0019] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0020] like Figure 1-3 As shown, the present invention provides a variable frequency starting control system for flue gas assisted steam flooding integrated equipment, including a three-phase power supply, a first motor, a second motor and a frequency converter: The input end of the frequency converter is connected to the output end of the three-phase power supply via a first circuit breaker, and the output end of the frequency converter is connected to the first motor and the second motor via a second contactor and a fourth contactor respectively; A first contactor is connected in parallel between the input end of the first circuit breaker and the output end of the second contactor, the input end of which is connected to the output end of the three-phase power supply via the second circuit breaker, and the output end of the first contactor is connected to the first motor; A third contactor is connected in parallel between the input end of the first circuit breaker and the output end of the fourth contactor, the input end of which is connected to the output end of the three-phase power supply via the third circuit breaker, and the output end of the third contactor is connected to the second motor; The control end of the frequency converter controls the on and off of the first contactor, the second contactor, the third contactor and the fourth contactor through a secondary side control loop to control the power supply access mode of the first motor and the second motor.

[0021] In the above technical solution, the three-phase power supply, the first motor, the second motor and the frequency converter are connected through three circuit breakers and four contactors to form two variable frequency starting circuits and two bypass operation circuits, which together constitute the hardware main circuit (primary side control circuit) of the variable frequency starting control system. The secondary side control circuit is used to cooperate with the control instruction (hardware switch / virtual signal) to realize the on-off control of each contactor, and then control the switching of each motor between the variable frequency starting and bypass operation states.

[0022] Taking a flue gas assisted steam flooding integrated equipment as an example, the above variable frequency start control system is applied. Figure 1As shown, the three-phase power supply is a three-phase AC power supply L1, L2, and L3; the first motor is the main motor M1 of the screw machine; the second motor is the main motor M2 of the reciprocating machine; the input ends of the frequency converter are R, S, and T, and the output ends are U, V, and W; the first circuit breaker is QFc, the second circuit breaker is QFd, and the third circuit breaker is QF2e; the first contactor is KM1, the second contactor is KM2, the third contactor is KM3, and the fourth contactor is KM4, and each contactor is an AC contactor.

[0023] Working principle of the primary side control circuit: When the main motor M1 of the screw machine is started by frequency conversion, the circuit breaker QFc is closed, and the three-phase power supply is connected to the R, S, T input terminals of the frequency converter, and then the U, V, W phases are output and connected to the main motor M1 of the screw machine through the second contactor KM2 to realize frequency conversion starting; when the main motor of the screw machine is started and needs to be switched to bypass, the second contactor KM2 is controlled to be disconnected, the first contactor KM1 is closed, and the circuit breaker QFd is closed. At this time, the three-phase power supply is connected to the main motor M1 of the screw machine through the first contactor KM1, so that it switches from frequency conversion to industrial frequency operation; Similarly, when the reciprocating machine main motor M2 needs to be driven, the circuit breaker QFc is closed, the R, S, and T terminals of the frequency converter are connected to the three-phase power supply, and the reciprocating machine main motor M2 is connected to the U, V, and W terminals of the frequency converter through the fourth contactor KM4 to achieve variable frequency starting; when the reciprocating machine main motor is started and needs to be switched to bypass, the fourth contactor KM4 is controlled to be disconnected and the third contactor KM3 is closed, and the circuit breaker QF2e is closed. At this time, the three-phase power supply is connected to the reciprocating machine main motor M2 through the third contactor KM3, so that it switches from variable frequency to industrial frequency operation.

[0024] Among them, the on and off of the first contactor, the second contactor, the third contactor and the fourth contactor are centrally controlled by the secondary side control circuit, and the on and off conditions of each contactor are fed back to the main circuit, realizing the variable frequency starting control and automatic switching of the dual motors in the flue gas assisted steam flooding integrated equipment. This starting method is a flexible starting method, which reduces the impact of the starting current on the power grid, improves the safety of the power grid operation, and enables the motor to automatically switch to bypass operation after the startup is completed, reducing the energy loss of the motor, and effectively improving the operating efficiency, reliability and safety of the equipment. In addition, the system adopts a single inverter one-to-two method, which reduces the number of starting devices, reduces the design and manufacturing costs and the probability of safety accidents, and further ensures the economic benefits of production.

[0025] In another technical solution, the variable frequency start-up control system of the flue gas assisted steam flooding integrated equipment, the secondary side control circuit includes multiple circuits, each circuit is powered by the same control power supply, the multiple circuits include a main control circuit, and the control method is to control and switch the on-off status of each contactor according to the operating state of the inverter, including: When the first motor needs to be started by frequency conversion, the second contactor is controlled to be closed, and the first circuit breaker is closed at the same time, so that the output voltage of the three-phase power supply is supplied to the first motor after being processed by the frequency converter; when the first motor is started, the control end of the frequency converter outputs a corresponding control signal to control the second contactor to be disconnected and the first contactor to be closed, and the second circuit breaker is closed at the same time, so that the first motor is switched to power frequency operation; When the second motor needs to be started by variable frequency, the fourth contactor is controlled to be closed, and the first circuit breaker is closed at the same time, so that the output voltage of the three-phase power supply is supplied to the second motor after being processed by the frequency converter; after the second motor is started, the control end of the frequency converter outputs a corresponding control signal to control the fourth contactor to be disconnected and the third contactor to be closed, and the third circuit breaker is closed at the same time, so that the second motor switches to industrial frequency operation.

[0026] In the above technical solution, the live wire of the control power supply is connected to the input node of each circuit through the fuse FU4, and the output node of each circuit is connected to the neutral point (N); the side of the input node close to the corresponding circuit load is the input side of the circuit, and the side of the output node close to the corresponding circuit load is the output side of the circuit.

[0027] In this embodiment, if Figure 2 As shown, the main control loop includes two loops, namely a variable frequency operation control loop and a variable frequency start / stop and switching control loop.

[0028] The input side of the variable frequency operation control loop is connected to the input end T2A of the variable frequency operation signal terminal of the inverter, and the output end T2C of the variable frequency operation signal terminal of the inverter is connected to the coil of the first variable frequency operation relay KA2 and the coil of the second variable frequency operation relay KA3 through the normally open contact of the second contactor KM2 and the normally open contact of the fourth contactor KM4 respectively, and then output; The input side of the variable frequency start-stop and switching control loop is connected to the input side terminals (1, 3, 7, 9) of the conversion switch nSA, and the two output side terminals (4, 8) of the conversion switch nSA are respectively connected to the first control module and the second control module through the stop switch (SBS1, SBS2) and then output, the first control module includes a first variable frequency start control circuit and a first switching control circuit connected in parallel, and the second control module includes a second variable frequency start control circuit and a second switching control circuit connected in parallel.

[0029] The first variable frequency starting control circuit includes a first starting switch SBF1, a normally closed contact of the first contactor KM1, a normally closed contact of the fourth contactor KM4, a coil of the second contactor KM2 and a normally closed contact of the first variable frequency operation relay KA2 connected in series in sequence, wherein the normally open contacts of the second contactor KM2 are connected on both sides of the first starting switch SBF1; the first switching control circuit includes a normally open contact of the first variable frequency operation relay KA2, a normally closed contact of the second contactor KM2 and a coil of the first contactor KM1 connected in series in sequence, wherein the normally open contacts of the first contactor KM1 are connected on both sides of the normally open contact of the first variable frequency operation relay KA2.

[0030] The second variable frequency starting control circuit includes a second starting switch SBF2, a normally closed contact of the second contactor KM2, a normally closed contact of the third contactor KM3, a coil of the fourth contactor KM4 and a normally closed contact of the second variable frequency operation relay KA3 connected in series in sequence, wherein the normally open contacts of the fourth contactor KM4 are connected in parallel on both sides of the second starting switch SBF2; the second switching control circuit includes a normally open contact of the second variable frequency operation relay KA3, a normally closed contact of the fourth contactor KM4 and a coil of the third contactor KM3 connected in series in sequence, wherein the normally open contacts of the third contactor KM3 are connected in parallel on both sides of the normally open contact of the second variable frequency operation relay KA3.

[0031] The connection circuit of the control power supply and the conversion switch nSA, the first stop switch SBS1, and the first variable frequency start control circuit corresponds to the "motor 1 variable frequency local remote start and stop circuit" in the figure (motor 1 is the first motor, that is, the main motor of the screw machine), and the connection circuit of the control power supply and the conversion switch nSA, the first stop switch SBS1, and the first switching control circuit corresponds to the "screw machine variable frequency switching power frequency circuit" in the figure; the connection circuit of the control power supply and the conversion switch nSA, the second stop switch SBS2, and the second variable frequency start control circuit corresponds to the "reciprocating machine variable frequency local remote start and stop circuit" in the figure, and the connection circuit of the control power supply and the conversion switch nSA, the second stop switch SBS2, and the second switching control circuit corresponds to the "reciprocating machine variable frequency switching power frequency circuit" in the figure. The two stop switches (SBS1, SBS2) are normally closed, and the two start switches (SBF1, SBF2) are normally open.

[0032] In the above embodiment, the conversion switch nSA is used to switch the working mode (variable frequency start / power frequency operation) of the first motor and the second motor. The variable frequency operation control circuit controls the on and off of the two variable frequency operation relays according to the variable frequency operation signal output by the variable frequency operation signal terminal, and then feeds back the operating state of the inverter to the variable frequency start and stop and switching control circuit to control the working state (on and off status) of each contactor. Here, the start and stop of the first motor and the second motor are realized by the stop switch (button) and the start switch (button), that is, the control mode is local control. In addition, in the main control circuit, the second contactor has an electrical interlocking relationship with the first contactor and the fourth contactor, and the fourth contactor has an electrical interlocking relationship with the second contactor and the third contactor, which protects the safety of system operation. At the same time, the first contactor, the second contactor, the third contactor and the fourth contactor are self-locking in their respective control circuits, which further ensures the stability of each motor when operating and switching under different working modes.

[0033] The control principle of the main control loop is: When the screw machine main motor M1 is started by frequency conversion, the conversion switch nSA is switched to the local control position of the screw machine, 115 is connected to 119, and the start switch SBF1 is pressed to turn on the first frequency conversion starting control circuit, and the coil of the second contactor KM2 is energized, and the second contactor KM2 is closed (the normally open contact of KM2 is turned on to ensure that the first frequency conversion starting control circuit is continuously turned on). At this time, the three-phase power supply is connected to the R, S, and T input terminals of the frequency converter and then outputs the U, V, and W phases and is connected to the screw machine main motor through the contactor KM2 to realize the frequency conversion starting of the screw machine main motor; when the screw machine main motor is started, DI1 and COM at the control end of the frequency converter receive a closed start signal, and the frequency converter runs to 50HZ for phase locking. After the phase locking is successful, the frequency conversion running signal of the frequency converter is The terminals (T2A, T2C) output a closing signal, (because the normally open contact of KM2 is turned on) to turn on the branch where the coil of the first variable frequency operation relay KA2 in the variable frequency operation control circuit is located, and the normally closed contact of KA2 is disconnected to disconnect the first variable frequency start control circuit, the coil of the second contactor KM2 is de-energized, and the contacts are reset. At the same time, the normally open contact of KA2 is closed, so that the first switching control circuit is turned on, and the coil of the first contactor KM1 is energized. The first contactor KM1 is self-locked to ensure that the first switching control circuit is continuously turned on. At this time, the coil of the first variable frequency operation relay KA2 is de-energized, and the contacts are reset. The inverter stops freely, and the three-phase power supply is connected to the main motor of the screw machine through the first contactor KM1. The main motor of the screw machine is switched to bypass operation (power frequency operation). In addition, pressing the stop switch SBS1 can cut off the conduction between the first control module and the conversion switch, and all components are reset to stop the main motor of the screw machine.

[0034] Similarly, when the reciprocating machine main motor M2 is frequency-controlled started, the conversion switch nSA is switched to the reciprocating machine local control position, 115 is connected to 219, and the start switch SBF2 is pressed to turn on the second frequency-controlled starting control circuit, and the coil of the fourth contactor KM4 is energized, and the fourth contactor KM4 is closed (KM4 is self-locked to ensure that the second frequency-controlled starting control circuit is continuously turned on). At this time, the three-phase power supply is connected to the R, S, and T input terminals of the frequency converter, and then the U, V, and W phases are output and connected to the reciprocating machine main motor through the fourth contactor KM4, so as to realize the frequency-controlled starting of the reciprocating machine main motor; when the reciprocating machine main motor is started, DI1 and COM of the frequency converter control end receive the closed starting signal, and the frequency converter runs to 50HZ for phase locking. After the phase locking is successful, the frequency converter runs at a frequency of 100Hz. The signal terminal (T2A, T2C) outputs a closed signal, (due to the normally open contact of KM4 being turned on) so that the branch where the coil of the second variable frequency operation relay KA3 in the variable frequency operation control circuit is located is turned on, and the normally closed contact of KA3 is disconnected to disconnect the second variable frequency start control circuit, and the coil of the fourth contactor KM4 is de-energized and the contacts are reset. At the same time, the normally open contact of KA3 is closed, so that the second switching control circuit is turned on, and the coil of the third contactor KM3 is energized. The third contactor KM3 is self-locked to ensure that the second switching control circuit is continuously turned on. At this time, the coil of the second variable frequency operation relay KA3 is de-energized, and the contacts are reset. The inverter stops freely, and the three-phase power supply is connected to the reciprocating machine main motor through the third contactor KM3. The reciprocating machine main motor switches to bypass operation (power frequency operation). In addition, pressing the stop switch SBS2 can cut off the conduction between the second control module and the conversion switch, and each device is reset to stop the reciprocating machine main motor.

[0035] In another technical solution, in the variable frequency starting control system of the flue gas assisted steam oil recovery integrated equipment, there are two control modes, local and remote, in the main control loop, both of which are used to realize the start, stop and switching control of the first motor and the second motor.

[0036] In this embodiment, the other two output-side terminals (2, 8) of the conversion switch are connected to the first remote control circuit and the second remote control circuit respectively.

[0037] The first remote control circuit includes a normally closed first remote switch K1 and a normally open second remote switch K2, the two ends of the first remote switch K1 are respectively connected to the output side terminal 2 of the conversion switch and the input node 121 of the first control module, and the two ends of the second remote switch K2 are respectively connected to the input node 121 and the output node 125 of the first starting switch SBF1.

[0038] The second remote control circuit includes a normally closed third remote switch K3 and a normally open fourth remote switch K4, the two ends of the third remote switch K3 are respectively connected to the output side terminal 8 of the conversion switch and the input node 221 of the second control module, and the two ends of the fourth remote switch K4 are respectively connected to the input node 221 and the output node 225 of the second starting switch SBF2.

[0039] Among them, K1, K2, K3, and K4 are all passive points, and the remote control drives K1, K2, K3, and K4 to switch the connection status through the PLC output level signal.

[0040] The remote control method of the main control loop includes: The conversion switch nSA is switched to the remote control position of the screw machine, 115 is connected to 117, and when it is necessary to control the frequency conversion start of the main motor of the screw machine, the remote output level signal activates K2 (reset after conduction), and the control power supply is connected to 125 through the conversion switch, K1, and K2, so that the coil of the second contactor KM2 is powered on, and KM2 is closed and self-locked, so that the first variable frequency drive control circuit is turned on, and the remote start of the screw machine is realized; when the main motor of the screw machine is started, since K2 has been reset, the control power supply is connected to 121 through the conversion switch nSA and K1 and then connected to the first control module, and the main control circuit can perform automatic switching control normally, so that the main motor of the screw machine is switched to industrial frequency operation; when it is necessary to control the main motor of the screw machine to stop, the remote output level signal activates K1 (reset after disconnection), so that each device can be reset.

[0041] The conversion switch nSA is switched to the reciprocating machine remote control position, 115 is connected to 217, and when the reciprocating machine main motor needs to be controlled to start with variable frequency, the remote output level signal causes K4 to act (reset after being turned on), and at this time, the control power supply is connected to 225 via the conversion switch, K3, and K4, so that the coil of the fourth contactor KM4 is powered on, and KM4 is closed and self-locked, thereby turning on the second variable frequency drive control circuit to realize the remote start of the reciprocating machine; after the reciprocating machine main motor is started, since K4 has been reset, the control power supply is turned on to 221 via the conversion switch nSA and K3 and connected to the second control module, and the main control circuit can perform automatic switching control normally, so that the reciprocating machine main motor is switched to industrial frequency operation; when the reciprocating machine main motor needs to be controlled to stop, the remote output level signal causes K3 to act (reset after being turned off), so that each device can be reset.

[0042] In another technical solution, the frequency conversion starting control system of the flue gas assisted steam oil recovery integrated equipment, the multiple circuits also include a frequency conversion fault control circuit, the input side of which is sequentially connected in series with the frequency conversion fault signal terminal of the frequency converter and the coil of the frequency conversion fault relay and then output, and the normally closed contact of the frequency conversion fault relay is serially connected in the main control circuit; a frequency conversion fault indication circuit, the input side of which is sequentially connected in series with the normally open contact of the frequency conversion fault relay and the frequency conversion fault indicator light and then output.

[0043] Among them, the input side of the frequency conversion fault control loop is connected to the input end T1A of the frequency conversion fault signal terminal of the frequency converter, and the output end T1C of the frequency conversion operation signal terminal of the frequency converter is connected to the coil of the frequency conversion fault relay KA1; at the same time, the normally closed contacts of the frequency conversion fault relay KA1 are respectively connected in series to the output sides of the first frequency conversion start control circuit, the first switching control circuit, the second frequency conversion start control circuit, and the second switching control circuit. Therefore, when the frequency conversion operation signal terminal outputs a fault signal, the coil of the frequency conversion fault relay KA1 is energized, and the normally closed contact of KA1 is disconnected, so that the frequency conversion start-stop and switching control circuits can be disconnected in time, effectively avoiding the safety risks caused by the frequency conversion fault; the normally open contact of KA1 is closed, and the frequency conversion fault indicator HY1 lights up, reminding the staff to handle the fault.

[0044] In addition, the frequency conversion start-up control system for flue gas assisted steam flooding integrated equipment also has a power monitoring function, and its power monitoring module JY is connected to the output end of the three-phase power supply. The power failure signal terminal of the power monitoring module JY is also connected in series between the input node of the main control loop and the fuse FU4. When the power monitoring module JY detects a power failure, the power failure signal terminal of the power monitoring module outputs a corresponding signal to disconnect the power connection of the main control loop to avoid damage to components. When the power monitoring function is provided, the input node of the frequency conversion fault control loop is also connected to the output end of the fault signal terminal of the power monitoring module.

[0045] In another technical solution, the said flue gas assisted steam flooding integrated equipment variable frequency start control system, the said multiple circuits also include an emergency stop control circuit, the input side of which is respectively connected in series with the coil of the external fault signal terminal, the emergency stop switch and the emergency stop signal relay, and then outputted, the said emergency stop signal relay is configured to control the opening of the electric operating mechanism of the said control power supply. Figure 4As shown, the control power supply is provided with an electric operating mechanism, whose terminal S2 is connected to the closing switch nSB2. When nSB2 is pressed, the S2 terminal is energized and the electric operating mechanism is closed; the terminal S4 of the electric operating mechanism is connected to the opening switch nSB1. When nSB1 is pressed, the S4 terminal is energized and the electric operating mechanism is closed. The normally open contacts of the emergency stop relay KA are connected in parallel on both sides of the opening switch nSB1. The emergency stop switch is an emergency stop button JT. When there is an emergency stop signal or an external fault signal, the emergency stop control circuit is turned on, the emergency stop relay KA coil is energized, and its normally open contact becomes a normally closed contact, so that the terminal S4 of the electric operating mechanism is energized, and the electric operating mechanism is controlled to automatically open, so as to disconnect the control power supply and realize the emergency stop function.

[0046] In another technical solution, the variable frequency start-up control system for the flue gas assisted steam flooding integrated equipment, the multiple circuits further include: The power indicator circuit has its input side connected to the power indicator light HW and then output; The first variable frequency start indication circuit, whose input side is connected to the first variable frequency start indicator light HR1 through the normally open contact of the second contactor KM2 and then output; The second variable frequency start indication circuit, whose input side is connected to the second variable frequency start indicator light HR2 via the normally open contact of the fourth contactor KM4 and then output; The first bypass operation indication circuit, whose input side is connected to the first bypass operation indicator light HR3 via the normally open contact of the first contactor KM1 and then output; The second bypass operation indication circuit has its input side connected to the second bypass operation indicator light HR4 via the normally open contact of the third contactor KM3 and then output.

[0047] In the above technical solution, when the power indicator light HW is on, it means that the control power supply of the secondary control circuit is normally connected; when the first variable frequency start indicator light HR1 is on, it means that the second contactor is closed and the first motor is in the variable frequency start state; when the second variable frequency start indicator light HR2 is on, it means that the fourth contactor is closed and the second motor is in the variable frequency start state; when the first bypass operation indicator light HR3 is on, it means that the first contactor is closed and the first motor is in the bypass operation (power frequency operation) state; when the second bypass operation indicator light HR4 is on, it means that the third contactor is closed and the second motor is in the bypass operation (power frequency operation) state. Thus, it is convenient for the staff to quickly and in real time monitor the current system operation status, and timely judge and handle possible faults.

[0048] In another technical solution, in the variable frequency starting control system of the flue gas assisted steam oil recovery integrated equipment, the first motor and the second motor need to be reset before the second starting at the variable frequency.

[0049] like Figure 1 As shown, the reset terminals DI2 and DI3 of the inverter are respectively connected to the reset button FW and the remote reset terminal K5 and then connected to the common terminal COM. Then, the inverter can be reset by inputting a reset signal to the inverter control terminal by pressing the reset button FW (local) or by triggering the PLC K5 action (remote). In this embodiment, when the first motor or the second motor is started for the second time, it is necessary to first input a reset signal (command) locally or remotely to reset the inverter and then switch to the variable frequency start mode of the corresponding motor.

[0050] In another technical solution, in the variable frequency starting control system of the flue gas assisted steam oil recovery integrated equipment, the primary winding of the first current transformer is connected in series between the output end of the first contactor KM1 and the first motor M1, and the secondary winding of the first current transformer is connected to the first thermal relay 1FR; the primary winding of the second current transformer is connected in series between the output end of the third contactor KM3 and the second motor M2, and the secondary winding of the second current transformer is connected to the second thermal relay 2FR.

[0051] In the above technical solution, when the motor switches to bypass (power frequency) operation, the current transformer converts the large current into a small current through the coil ratio, and the thermal relay protects the working circuit (bypass) by detecting the secondary current of the current transformer. Conventional electrical detection equipment (such as ammeter, etc.) can also be set on the secondary side of the current transformer, so that the measurement of current, power and fault signals is achieved through electrical isolation, and the operation of the equipment can be monitored safely and effectively. In this embodiment, each current transformer includes three coils, and the corresponding thermal relay and the current transformer are connected in star, and the two ends of the thermal relay are respectively connected to the two terminals of the secondary winding of the current transformer, and one end is grounded.

[0052] In addition, the normally closed contact of the thermal relay FR1 is connected in series in the first switching control circuit, and the normally closed contact of the thermal relay FR2 is connected in series in the second switching control circuit to perform control circuit protection.

[0053] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A variable frequency starting control system for flue gas assisted steam flooding integrated equipment, comprising a three-phase power supply, a first motor, a second motor and a frequency converter, characterized in that: The input end of the frequency converter is connected to the output end of the three-phase power supply via a first circuit breaker, and the output end of the frequency converter is connected to the first motor and the second motor via a second contactor and a fourth contactor respectively; A first contactor is connected in parallel between the input end of the first circuit breaker and the output end of the second contactor, the input end of which is connected to the output end of the three-phase power supply via the second circuit breaker, and the output end of the first contactor is connected to the first motor; A third contactor is connected in parallel between the input end of the first circuit breaker and the output end of the fourth contactor, the input end of which is connected to the output end of the three-phase power supply via the third circuit breaker, and the output end of the third contactor is connected to the second motor; The control end of the frequency converter controls the on and off of the first contactor, the second contactor, the third contactor and the fourth contactor through a secondary side control loop.

2. The variable frequency start-up control system for flue gas assisted steam flooding integrated equipment according to claim 1, characterized in that: The secondary side control circuit includes multiple circuits, each circuit is powered by the same control power supply, and the multiple circuits include a main control circuit, and its control method is to control and switch the on-off status of each contactor according to the operating state of the inverter, including: When the first motor needs to be started by frequency conversion, the second contactor is controlled to be closed, and the first circuit breaker is closed at the same time, so that the output voltage of the three-phase power supply is supplied to the first motor after being processed by the frequency converter; when the first motor is started, the control end of the frequency converter outputs a corresponding control signal to control the second contactor to be disconnected and the first contactor to be closed, and the second circuit breaker is closed at the same time, so that the first motor is switched to power frequency operation; When the second motor needs to be started by variable frequency, the fourth contactor is controlled to be closed, and the first circuit breaker is closed at the same time, so that the output voltage of the three-phase power supply is supplied to the second motor after being processed by the frequency converter; after the second motor is started, the control end of the frequency converter outputs a corresponding control signal to control the fourth contactor to be disconnected and the third contactor to be closed, and the third circuit breaker is closed at the same time, so that the second motor switches to industrial frequency operation.

3. The variable frequency start-up control system for flue gas assisted steam flooding integrated equipment according to claim 2, characterized in that: In the main control loop, the second contactor is electrically interlocked with the first contactor and the fourth contactor, and the fourth contactor is electrically interlocked with the second contactor and the third contactor.

4. The variable frequency start-up control system for flue gas assisted steam flooding integrated equipment according to claim 2, characterized in that: There are two control modes in the main control loop: local and remote, both of which are used to realize the start, stop and switching control of the first motor and the second motor.

5. The variable frequency start-up control system for flue gas assisted steam flooding integrated equipment according to claim 2, characterized in that: The multiple circuits also include a frequency conversion fault control circuit, an input side of which is connected in series with the frequency conversion fault signal terminal of the frequency converter and the coil of the frequency conversion fault relay and then output, and the normally closed contact of the frequency conversion fault relay is connected in series in the main control circuit; a frequency conversion fault indication circuit, an input side of which is connected in series with the normally open contact of the frequency conversion fault relay and the frequency conversion fault indicator light and then output.

6. The variable frequency start-up control system for flue gas assisted steam flooding integrated equipment according to claim 2, characterized in that: The multiple circuits also include an emergency stop control circuit, the input side of which is respectively connected in series with an external fault signal terminal, an emergency stop switch and a coil of an emergency stop signal relay and then outputted. The emergency stop signal relay is configured to control the opening of an electric operating mechanism of the control power supply.

7. The variable frequency start-up control system for flue gas assisted steam flooding integrated equipment according to claim 2, characterized in that: The plurality of loops further comprises: The power indicator circuit has an input side connected to the power indicator light and then output; The first variable frequency start indication circuit, whose input side is connected to the first variable frequency start indicator light through the normally open contact of the second contactor and then output; A second variable frequency start indication circuit, the input side of which is connected to the second variable frequency start indicator light via the normally open contact of the fourth contactor and then output; A first bypass operation indication circuit, the input side of which is connected to the first bypass operation indicator light via the normally open contact of the first contactor and then output; The second bypass operation indicating circuit has an input side which is connected to the second bypass operation indicating lamp via the normally open contact of the third contactor and then outputs.

8. The variable frequency start-up control system for flue gas assisted steam flooding integrated equipment according to claim 2, characterized in that: The first motor and the second motor need to be reset before the second start by frequency conversion.

9. The variable frequency start-up control system for flue gas assisted steam flooding integrated equipment according to claim 1, characterized in that: A primary winding of a first current transformer is connected in series between the output end of the first contactor and the first motor, and a secondary winding of the first current transformer is connected to a first thermal relay; a primary winding of a second current transformer is connected in series between the output end of the third contactor and the second motor, and a secondary winding of the second current transformer is connected to a second thermal relay.

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