Safety control method and system for air compressor of thermal power plant based on DCS (Distributed Control System)

Abstract

The embodiment of the invention provides a thermal power plant air compressor safety control method and system based on a DCS, and the method comprises the steps that air compressors in a plurality of units of a thermal power plant are monitored through a plurality of unit DCS systems and a whole-plant public DCS system, and the plurality of unit DCS systems are connected with the whole-plant public DCS system; and when a certain DCS system fails, the air compressor monitored by the failed DCS system is switched into a local control mode. The air compressor can be reliably monitored under various working conditions, the pressure stability of the instrument compressed air for the power plant is guaranteed, and the safety of a power plant unit and the automatic operation control level of the power plant unit are improved.

Description

Technical Field

[0001] This document relates to the field of computer technology, and in particular to a DCS system-based thermal power plant air compressor safety control method and system. Background Art

[0002] At present, various pneumatic actuators need to be equipped with air source systems. As a power source for compressed air, air compressors need reliable operation and monitoring, which is one of the important requirements for ensuring production safety. At present, most air compressors are designed with a control system to achieve control. The advantage is that the logic is simple and easy to implement, but there are major hidden dangers. When the system fails, the remote monitoring of the air compressor fails, especially in power plants that implement large centralized control, which are less equipped with manpower and are difficult to deal with in time after a problem occurs. Summary of the invention

[0003] The purpose of the present invention is to provide a DCS system-based thermal power plant air compressor safety control method and system, aiming to solve the above-mentioned problems in the prior art.

[0004] The present invention provides a DCS system-based thermal power plant air compressor safety control method, comprising:

[0005] The air compressors in multiple units of a thermal power plant are monitored by multiple unit DCS systems and the plant-wide public DCS system, where multiple unit DCS systems are connected to the plant-wide public DCS system;

[0006] When a DCS system fails, the air compressor monitored by the failed DCS system is switched to local control mode.

[0007] The present invention provides a DCS-based thermal power plant air compressor safety control system, comprising:

[0008] The air compressors in multiple units of a thermal power plant are connected to the DCS systems of multiple units and the public DCS system of the whole plant respectively, so as to be controlled by the corresponding DCS systems;

[0009] The DCS system includes multiple unit DCS systems and a plant-wide common DCS system, which are respectively connected to the air compressors in the multiple units and are used to monitor the air compressors in the multiple units. When a DCS system fails, the air compressor monitored by the failed DCS system is switched to a local control mode, wherein the multiple unit DCS systems are respectively connected to the plant-wide common DCS system.

[0010] By adopting the embodiment of the present invention, the air compressors are dispersed to each independent DCS system for control and control strategy, ensuring that when a certain independent system fails, all air compressors will not be out of control, affecting the safe operation of the unit. The embodiment of the present invention realizes an organic combination of the control strategy method of the DCS system by configuring each air compressor control in a connection mode of different DCS systems, achieving the control target, and can quickly realize the mechanism of separation from the control when an abnormality occurs, thereby ensuring the reliable monitoring and control of the air compressor, an important public equipment, and realizing the reliable monitoring of the air compressor under various working conditions, ensuring the stability of the compressed air pressure used by the power plant instrument, and improving the safety of the power plant unit and its automatic operation control level. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0012] Figure 1 is a flow chart of a thermal power plant air compressor safety control method based on a DCS system according to an embodiment of the present invention;

[0013] Figure 2 is a schematic diagram of a connection method between a device and a system according to an embodiment of the present invention;

[0014] Figure 3 is a signaling processing flow chart of the air compressor safety control strategy according to an embodiment of the present invention;

[0015] Figure 4 It is a schematic diagram of a thermal power plant air compressor safety control system based on a DCS system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the following will be combined with the drawings in one or more embodiments of this specification to clearly and completely describe the technical solutions in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this document.

[0017] Method Embodiment

[0018] According to an embodiment of the present invention, a DCS system-based thermal power plant air compressor safety control method is provided. Figure 1 FIG. 1 is a flow chart of a method for safely controlling an air compressor in a thermal power plant based on a DCS system according to an embodiment of the present invention. Figure 1 As shown, the DCS system-based thermal power plant air compressor safety control method according to an embodiment of the present invention specifically includes:

[0019] Step S101, air compressors in multiple units of a thermal power plant are monitored by multiple unit DCS systems and a plant-wide common DCS system, wherein the multiple unit DCS systems are respectively connected to the plant-wide common DCS system; specifically, the following steps are included:

[0020] The start and stop control instructions and status signals of the air compressors in multiple units of the thermal power plant are connected to the DO and DI modules of the DCS system by hard wiring to achieve start and stop control and status signal monitoring;

[0021] The internal operation information of the air compressors in multiple units of a thermal power plant is connected to the communication interface of the DCS system that controls the start-up of the air compressors by means of communication, so that the DCS system can collect and monitor the internal information of the air compressors.

[0022] Step S102, when a DCS system fails, the air compressor monitored by the failed DCS system is switched to a local control mode. Specifically, it includes:

[0023] When the controller connected to the air compressor fails or the DCS system fails, the DCS system sends fault information to the air compressor through the normally closed contact of the output relay of the DO module, and the air compressor switches to the local control mode.

[0024] The above method of the embodiment of the present invention further includes:

[0025] When the DCS system is normal and the corresponding air compressor is in non-local mode, the DCS system sets the corresponding air compressor to local control, and remote control start and stop of the air compressor is realized through the DCS system;

[0026] When the DCS system sets the corresponding air compressor to remote control, the pre-set control strategy implements the interlocking control function of the air compressor. Specifically, it includes:

[0027] When all air compressors are normal and all DCS systems are normal and in remote control mode, if a certain air compressor trips during operation, the other air compressors will set interlock priority levels according to the situation. The air compressor with a higher interlock priority level will be interlocked and started first. If the interlock fails and after a predetermined period of time, another air compressor will be interlocked and started. When other air compressors are running, if one of them trips or one of the DCS systems fails and switches the air compressor to local control mode, an alarm will be issued. When the main pipe pressure is low, the standby air compressor will be interlocked and started.

[0028] When an air compressor or the DCS system connected to it fails or is under maintenance, the control logic shields the faulty device and prohibits it from participating in the interlocking control. Other air compressors are interconnected. When the running air compressor is blocked, the interlocking starts another air compressor that has been interlocked and is normal.

[0029] When only one air compressor and the DCS system it is connected to are normal, the remote control of the air compressor is normal, the system interlocking function is lost, and the control of other air compressors is switched to local control mode;

[0030] When the air compressor is in local control mode, the corresponding DCS system has control authority, and other DCS systems and interlocks cannot remotely control or interlock the start and stop of the air compressor;

[0031] When the air compressor is in remote control mode and the air compressor and DCS system are normal and a unit obtains control, the remote control rights of all air compressors of the operator station of the unit are granted.

[0032] The above technical solution of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings.

[0033] like Figure 2 As shown, the control of Unit 1 and Unit 2 of the thermal power plant adopts the control mode of Unit 1 DCS system, Unit 2 DCS system and the whole plant public DCS system to realize the control mode of the two units. The three air compressors A, B and C are configured respectively. Air compressor A is remotely controlled to start and stop and monitor by DCS of Unit 1, air compressor C is remotely controlled to start and stop and monitor by DCS of Unit 2, and air compressor B is remotely controlled to start and stop and monitor by the public DCS of all pressures. This method realizes that when the DCS system fails, the unit can still monitor the operation of the air compressor of the non-faulty DCS, and the air compressor monitored by the faulty DCS system is switched to the local control mode, so as to avoid that all air compressors are controlled by one DCS system and lose the remote operation monitoring of the air compressors in case of failure or maintenance.

[0034] (I) Connection of air compressor control instructions, status signals and information communication signals with the DCS system

[0035] The start and stop control instructions and status signals of the air compressor are connected to the DO and DI modules of the DCS system through hard wiring to realize the start and stop control of the air compressor; when the controller connected to the compressor fails or the DCS fails, the DCS sends the fault information to the air compressor through the normally closed contact of the output relay of the DO module to realize the local control mode of the air compressor; the internal operation information of the air compressor is connected to the communication interface of the DCS system that controls the start of the air compressor through communication, so that the DCS system can collect and monitor the internal information of the air compressor. When the fault contact is mistakenly sent or the connected controller fails, the operating parameters of the local instrument air compressor can still be monitored.

[0036] (II) Remote control function of a single air compressor

[0037] Each DCS system and the air compressor connected to it are equipped with remote control, local control, and local mode. When the DCS system fails, it automatically switches to local mode; when the DCS is normal and the air compressor is not in local mode, the DCS is local control, which can realize remote control start and stop of the air compressor; when the air compressor control is switched to remote control, the control strategy realizes the interlocking function.

[0038] The signal of air compressor A is connected to the DCS system of unit 1, and the DCS has the function of independent remote control of the start and stop of the air compressor; the signal of air compressor B is connected to the public DCS system, and the DCS has the function of independent remote control of the start and stop of the air compressor; the signal of air compressor C is connected to the DCS system of unit 2, and the DCS has the function of independent remote control of the start and stop of the air compressor.

[0039] When the DCS system of unit 1 fails or shuts down, the normally closed contact indicating the DCS system failure closes, and air compressor A is cut off for local control, which does not affect the signal collection, remote control, alarm and signal communication between air compressors B and C and the DCS to which they are connected; when the DCS system of unit 2 fails or shuts down, the normally closed contact indicating the DCS system failure closes, and air compressor C is cut off for local control, which does not affect the signal collection, remote control, alarm and signal communication between air compressors A and B; when the public DCS system fails or shuts down, the normally closed contact indicating the DCS system failure closes, and air compressor B is cut off for local control, which does not affect the signal collection, remote control, alarm and signal communication between air compressors A and C.

[0040] (III) Safety input and cut-off control strategy of air compressor

[0041] like Figure 3As shown, when the three air compressors are normal and the DCS systems are normal and in remote control mode, when air compressor A trips during operation, air compressors B and C can set the interlock priority level according to the situation. The one with the higher level will be started first. If the interlock fails and after a certain period of time, the other air compressor will be started. When two air compressors are running, if one of them trips or one of the DCS systems fails and the air compressor is switched to local mode, an alarm should be issued. When the main pipe pressure is low, the standby air compressor will be started.

[0042] When an air compressor or the DCS system connected to it fails or is under maintenance, the control logic shields the faulty equipment and prohibits it from participating in the interlocking control. The other two air compressors can be interconnected. When the running air compressor is shut down, the other interlocked and normal air compressor can be started.

[0043] When only one air compressor and the DCS system it is connected to are normal, the remote control of the air compressor is normal, the system interlocking function is lost, and the other two air compressors are controlled in local mode.

[0044] (IV) Unit control rights obtain control rights, and can realize control rights over all air compressors

[0045] When the air compressor is in local control mode, the DCS system connected to it has control authority, and other DCS systems and interlocks cannot remotely control or interlock start and stop the air compressor.

[0046] When the air compressor is in remote control mode and the air compressor and DCS system are normal and Unit 1 obtains control, the Unit 1 operator station can achieve remote control of the three air compressors.

[0047] When the air compressor is in remote control mode and the air compressor and DCS system are normal and Unit 2 obtains control, the Unit 2 operator station can achieve remote control of the three air compressors.

[0048] When the air compressor is in remote control mode and the air compressor and DCS system are normal and the public DCS system operator station obtains control, remote control of the three air compressors can be achieved.

[0049] System Example

[0050] According to an embodiment of the present invention, a DCS-based thermal power plant air compressor safety control system is provided. Figure 4 FIG. 1 is a schematic diagram of a thermal power plant air compressor safety control system based on a DCS system according to an embodiment of the present invention. Figure 4 As shown, the thermal power plant air compressor safety control system based on the DCS system according to an embodiment of the present invention specifically includes:

[0051] The air compressors 40 in the multiple units of the thermal power plant are respectively connected to the DCS systems of the multiple units and the DCS system of the whole plant, so as to be controlled by the corresponding DCS systems;

[0052] The DCS system 42 includes multiple unit DCS systems and a plant-wide common DCS system, which are respectively connected to the air compressors in the multiple units and are used to monitor the air compressors in the multiple units. When a DCS system fails, the air compressor monitored by the failed DCS system is switched to a local control mode, wherein the multiple unit DCS systems are respectively connected to the plant-wide common DCS system.

[0053] The start and stop control instructions and status signals of the air compressors in multiple units of a thermal power plant are connected to the DO and DI modules of the DCS system by hard wiring to achieve start and stop control and status signal monitoring; the internal operation information of the air compressors in multiple units of a thermal power plant is connected to the communication interface of the DCS system that controls the start of the air compressor by communication to enable the DCS system to collect and monitor the internal information of the air compressor.

[0054] The DCS system 42 is specifically used for:

[0055] When the controller connected to the air compressor fails or the DCS system fails, the fault information is sent to the air compressor through the normally closed contact of the output relay of the DO module, and the air compressor switches to the local control mode.

[0056] The DCS system is further used for:

[0057] When the DCS system is normal and the corresponding air compressor is in non-local mode, set the corresponding air compressor to local control and realize remote control start and stop of the air compressor through the DCS system;

[0058] When the DCS system sets the corresponding air compressor to remote control, the interlocking control function of the air compressor is realized by the pre-set control strategy. Specifically:

[0059] When all air compressors are normal and all DCS systems are normal and in remote control mode, if a certain air compressor trips during operation, the other air compressors will set interlock priority levels according to the situation. The air compressor with a higher interlock priority level will be interlocked and started first. If the interlock fails and after a predetermined period of time, another air compressor will be interlocked and started. When other air compressors are running, if one of them trips or one of the DCS systems fails and switches the air compressor to local control mode, an alarm will be issued. When the main pipe pressure is low, the standby air compressor will be interlocked and started.

[0060] When an air compressor or the DCS system connected to it fails or is under maintenance, the control logic shields the faulty device and prohibits it from participating in the interlocking control. Other air compressors are interconnected. When the running air compressor is blocked, the interlocking starts another air compressor that has been interlocked and is normal.

[0061] When only one air compressor and the DCS system it is connected to are normal, the remote control of the air compressor is normal, the system interlocking function is lost, and the control of other air compressors is switched to local control mode;

[0062] When the air compressor is in local control mode, the corresponding DCS system has control authority, and other DCS systems and interlocks cannot remotely control or interlock the start and stop of the air compressor;

[0063] When the air compressor is in remote control mode and the air compressor and DCS system are normal and a unit obtains control, the remote control rights of all air compressors of the operator station of the unit are granted.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A safety control method for air compressors in thermal power plants based on a DCS system, characterized in that: include: The air compressors in multiple units of a thermal power plant are monitored by multiple unit DCS systems and the plant-wide public DCS system, where multiple unit DCS systems are connected to the plant-wide public DCS system; When a DCS system fails, the air compressor monitored by the failed DCS system is switched to local control mode.

2. The method according to claim 1, characterized in that The air compressor control in multiple units of a thermal power plant is monitored by multiple unit DCS systems and the whole plant's public DCS system, including: The start and stop control instructions and status signals of the air compressors in multiple units of the thermal power plant are connected to the DO and DI modules of the DCS system by hard wiring to achieve start and stop control and status signal monitoring; The internal operation information of the air compressors in multiple units of a thermal power plant is connected to the communication interface of the DCS system that controls the start-up of the air compressors by means of communication, so that the DCS system can collect and monitor the internal information of the air compressors.

3. The method according to claim 2, characterized in that When a DCS system fails, the air compressor monitored by the failed DCS system is switched to the local control mode, specifically including: When the controller connected to the air compressor fails or the DCS system fails, the DCS system sends fault information to the air compressor through the normally closed contact of the output relay of the DO module, and the air compressor switches to the local control mode.

4. The method according to claim 1, characterized in that: The method further comprises: When the DCS system is normal and the corresponding air compressor is in non-local mode, the DCS system sets the corresponding air compressor to local control, and remote control start and stop of the air compressor is realized through the DCS system; When the DCS system sets the corresponding air compressor to remote control, the interlocking control function of the air compressor is realized by the pre-set control strategy.

5. The method according to claim 4, characterized in that When the DCS system sets the corresponding air compressor to remote control, the interlocking control functions of the air compressor implemented by the pre-set control strategy include: When all air compressors are normal and all DCS systems are normal and in remote control mode, if a certain air compressor trips during operation, the other air compressors will set interlock priority levels according to the situation. The air compressor with a higher interlock priority level will be interlocked and started first. If the interlock fails and after a predetermined period of time, another air compressor will be interlocked and started. When other air compressors are running, if one of them trips or one of the DCS systems fails and switches the air compressor to local control mode, an alarm will be issued. When the main pipe pressure is low, the standby air compressor will be interlocked and started. When an air compressor or the DCS system connected to it fails or is under maintenance, the control logic shields the faulty device and prohibits it from participating in the interlocking control. Other air compressors are interconnected. When the running air compressor is blocked, the interlocking starts another air compressor that has been interlocked and is normal. When only one air compressor and the DCS system it is connected to are normal, the remote control of the air compressor is normal, the system interlocking function is lost, and the control of other air compressors is switched to local control mode; When the air compressor is in local control mode, the corresponding DCS system has control authority, and other DCS systems and interlocks cannot remotely control or interlock the start and stop of the air compressor; When the air compressor is in remote control mode and the air compressor and DCS system are normal and a unit obtains control, the remote control rights of all air compressors of the operator station of the unit are granted.

6. A DCS-based thermal power plant air compressor safety control system, characterized in that: include: The air compressors in multiple units of a thermal power plant are connected to the DCS systems of multiple units and the public DCS system of the whole plant respectively, so as to be controlled by the corresponding DCS systems; The DCS system includes multiple unit DCS systems and a plant-wide common DCS system, which are respectively connected to the air compressors in the multiple units and are used to monitor the air compressors in the multiple units. When a DCS system fails, the air compressor monitored by the failed DCS system is switched to a local control mode, wherein the multiple unit DCS systems are respectively connected to the plant-wide common DCS system.

7. The system according to claim 6, characterized in that The start and stop control instructions and status signals of the air compressors in multiple units of a thermal power plant are connected to the DO and DI modules of the DCS system by hard wiring to achieve start and stop control and status signal monitoring; the internal operation information of the air compressors in multiple units of a thermal power plant is connected to the communication interface of the DCS system that controls the start of the air compressor by communication to enable the DCS system to collect and monitor the internal information of the air compressor.

8. The system according to claim 7, characterized in that The DCS system is specifically used for: When the controller connected to the air compressor fails or the DCS system fails, the fault information is sent to the air compressor through the normally closed contact of the output relay of the DO module, and the air compressor switches to the local control mode.

9. The system according to claim 6, characterized in that The DCS system is further used for: When the DCS system is normal and the corresponding air compressor is in non-local mode, set the corresponding air compressor to local control and realize remote control start and stop of the air compressor through the DCS system; When the DCS system sets the corresponding air compressor to remote control, the interlocking control function of the air compressor is realized by the pre-set control strategy.

10. The system according to claim 9, characterized in that The DCS system is specifically used for: When all air compressors are normal and all DCS systems are normal and in remote control mode, if a certain air compressor trips during operation, the other air compressors will set interlock priority levels according to the situation. The air compressor with a higher interlock priority level will be interlocked and started first. If the interlock fails and after a predetermined period of time, another air compressor will be interlocked and started. When other air compressors are running, if one of them trips or one of the DCS systems fails and switches the air compressor to local control mode, an alarm will be issued. When the main pipe pressure is low, the standby air compressor will be interlocked and started. When an air compressor or the DCS system connected to it fails or is under maintenance, the control logic shields the faulty device and prohibits it from participating in the interlocking control. Other air compressors are interconnected. When the running air compressor is blocked, the interlocking starts another air compressor that has been interlocked and is normal. When only one air compressor and the DCS system it is connected to are normal, the remote control of the air compressor is normal, the system interlocking function is lost, and the control of other air compressors is switched to local control mode; When the air compressor is in local control mode, the corresponding DCS system has control authority, and other DCS systems and interlocks cannot remotely control or interlock the start and stop of the air compressor; When the air compressor is in remote control mode and the air compressor and DCS system are normal and a unit obtains control, the remote control rights of all air compressors of the operator station of the unit are granted.

Images