Thermal power plant freezing dryer control circuit

Abstract

The embodiment of the invention provides a thermal power plant freezing dryer control circuit, which comprises a freezing dryer control loop which comprises a start-stop module, a freezing dryer control relay and a fault normally open contact which are connected in series; the start-stop module is used for connecting or disconnecting a refrigeration dryer control loop; the fault signal loop comprises a fault relay connected with the fault normally-open contact, and the fault relay controls the fault normally-open contact to be disconnected when powered on. The drain valve control loop is electrically connected with the refrigeration dryer control relay and the drain valve, and controls the drain valve to be opened and closed according to the refrigeration dryer control relay; and the air cooler control loop is electrically connected with the refrigeration dryer control relay and the air cooler, and controls the air cooler to start and stop according to the refrigeration dryer control relay. According to the embodiment of the invention, the refrigeration dryer is composed of simple electrical components, is low in cost, high in reliability, simple in maintenance process and easy to operate, can replace a small controller or be used as a standby while realizing normal operation, and has high applicability.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of cold dryer control in thermal power plants, and in particular relate to a cold dryer control circuit in thermal power plants. Background Art

[0002] In the production process of thermal power plants, the main function of the cold dryer is to reduce the temperature of compressed air and remove the moisture in it to provide dry compressed air. The cold dryer, also known as a refrigerated dryer, is an important component of the pneumatic system. It uses new technology to exchange heat between refrigerant and compressed air to reduce the temperature of compressed air to a dew point temperature of 2 to 10°C, thereby effectively removing the moisture in it.

[0003] At present, most cold dryers in thermal power plants are controlled by PLC, which is based on a small controller and writes a control program to complete the control and monitoring of the cold dryer.

[0004] However, during the configuration process of small controllers, maintenance personnel must have a certain level of professionalism and high level requirements; secondly, small controllers have poor versatility, and the connectors, connection methods, and configuration methods of different controllers are not the same. When a controller fails, it is often necessary to replace the controller of the same model to restore operation; in addition, small controllers are expensive, which makes the cost of the cold dryer control system high. Summary of the invention

[0005] The embodiment of the present disclosure aims to solve at least one of the technical problems existing in the prior art, and provides a control circuit of a cold dryer in a thermal power plant, comprising:

[0006] The cold dryer control circuit includes a cold dryer local start-stop module, a cold dryer control relay and a fault normally open contact connected in series; wherein the cold dryer local start-stop module is used to turn on or off the cold dryer control circuit;

[0007] A fault signal circuit, used to be turned on when the cold dryer fails; the fault signal circuit includes a fault relay connected to the fault normally open contact, and the fault relay is used to control the fault normally open contact to be disconnected when powered;

[0008] A drain valve control circuit is electrically connected to the cold dryer control relay and the drain valve, respectively, and is used to control the drain valve to open and close when the cold dryer control relay is powered on and off;

[0009] The air cooler control circuit is electrically connected to the cold dryer control relay and the air cooler, and is used to control the start and stop of the air cooler when the cold dryer control relay is energized or de-energized.

[0010] Furthermore, the local start-stop module of the cold dryer includes a local start normally closed contact and a local stop normally open contact connected in series;

[0011] When the local start-up normally closed contact is closed, the cold dryer control circuit is connected; when the local stop-operation normally open contact is disconnected, the cold dryer control circuit is disconnected.

[0012] Furthermore, the cold dryer control circuit is also connected in series with a local / remote switch and also includes a cold dryer remote start / stop module connected in parallel with the cold dryer local start / stop module;

[0013] The local / remote switching switch is used to selectively connect to the local start / stop module of the cold dryer or the remote start / stop module of the cold dryer;

[0014] The remote start and stop module of the cold dryer includes a remote start normally closed contact and a remote stop normally open contact connected in series;

[0015] When the local / remote switching switch is connected to the remote start / stop module of the cold dryer and the remote start normally closed contact is closed, the cold dryer control circuit is turned on; when the local / remote switching switch is connected to the remote start / stop module of the cold dryer and the remote stop normally open contact is disconnected, the cold dryer control circuit is cut off.

[0016] Furthermore, the cold dryer local start-stop module further includes a cold dryer control relay first contact connected in parallel with the local start normally closed contact; the cold dryer remote start-stop module further includes a cold dryer control relay second contact connected in parallel with the remote start normally closed contact;

[0017] The first contact of the cold dryer control relay and the second contact of the cold dryer control relay are respectively connected to the cold dryer control relay, and are used to close when the cold dryer control relay is energized and to open when the cold dryer control relay is de-energized.

[0018] Optionally, the drain valve control circuit includes a third contact of a cold dryer control relay and a drain valve control relay connected in series with each other;

[0019] The third contact of the cold dryer control relay is connected to the cold dryer control relay, and is used to close when the cold dryer control relay is powered on, and to open when the cold dryer control relay is powered off;

[0020] The drain valve control relay is used to be electrically connected to the drain valve; when the drain valve control relay is energized, the drain valve is controlled to be opened, and when the drain valve control relay is de-energized, the drain valve is controlled to be closed.

[0021] Furthermore, the drain valve control circuit is also connected in series with a timing switch;

[0022] The timing switch is used to close when the third contact of the cold dryer control relay is closed, and to open after a predetermined time has passed.

[0023] Optionally, the air cooler control circuit includes a fourth contact of a cold dryer control relay and an air cooler control relay connected in series with each other;

[0024] The fourth contact of the cold dryer control relay is connected to the cold dryer control relay, and is used to close when the cold dryer control relay is powered on, and to open when the cold dryer control relay is powered off;

[0025] The air cooler control relay is used to be electrically connected to the air cooler; when the air cooler control relay is energized, the air cooler is controlled to start, and when the air cooler control relay is de-energized, the air cooler is controlled to stop.

[0026] Optionally, the thermal power plant cold dryer control circuit also includes an operation signal circuit;

[0027] The operation signal circuit includes a fifth contact of the cold dryer control relay and an operation signal light connected in series, and a DCS operation signal sending module connected in parallel with the operation signal light;

[0028] The fifth contact of the cold dryer control relay is connected to the cold dryer control relay, and is used for closing when the cold dryer control relay is energized and opening when the cold dryer control relay is de-energized.

[0029] Optionally, the thermal power plant cold dryer control circuit also includes a shutdown signal circuit;

[0030] The shutdown signal circuit includes a sixth contact of the cold dryer control relay and a shutdown signal light connected in series, and a DCS shutdown signal sending module connected in parallel with the shutdown signal light;

[0031] The sixth contact of the cold dryer control relay is connected to the cold dryer control relay, and is used for opening when the cold dryer control relay is energized and closing when the cold dryer control relay is de-energized.

[0032] Optionally, the fault signal circuit further includes a fault signal lamp connected in parallel with the fault relay;

[0033] The fault relay is also used to be electrically connected to a DCS fault signal sending module; when the fault relay is energized, the DCS fault signal sending module is controlled to send a DCS fault signal.

[0034] A control circuit for a cold dryer in a thermal power plant according to an embodiment of the present disclosure is constructed by using simple electrical components, has low cost, high reliability, simple maintenance process, and is easy to operate. It can replace a professional microcontroller or be used as a backup while achieving normal operation of the cold dryer and monitoring of its operating status, and has high applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a schematic structural diagram of a control circuit of a cold dryer in a thermal power plant according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0037] In addition, the described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the present disclosure.

[0038] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0039] It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another component. Therefore, the first component discussed below can be referred to as the second component without departing from the teachings of the concepts of the present disclosure. As used in this disclosure, the term "and / or" includes any one of the associated listed items and all combinations of one or more.

[0040] Those skilled in the art will appreciate that the drawings are merely schematic diagrams of example embodiments, and the modules or processes in the drawings are not necessarily necessary for implementing the present disclosure, and therefore cannot be used to limit the protection scope of the present disclosure.

[0041] like Figure 1As shown, an embodiment of the present disclosure provides a control circuit for a cold dryer in a thermal power plant, the circuit comprising:

[0042] The cold dryer control circuit 100 includes a cold dryer local start-stop module M1, a cold dryer control relay KA1 and a fault normally open contact KA2-1 which are connected in series. The cold dryer local start-stop module M1 is used to turn on or off the cold dryer control circuit 100.

[0043] The fault signal circuit 200 is used to be turned on when the cold dryer fails. The fault signal circuit 200 includes a fault relay KA2 connected to the fault normally open contact KA2-1, and the fault relay KA2 is used to control the fault normally open contact KA2-1 to be disconnected when powered. Specifically, a variety of different fault switches can be set in the fault signal circuit 200 in parallel with each other, and the corresponding fault switch is closed when the cold dryer fails. For example, switch S21 is closed when a fuse occurs, switch S22 is closed when a refrigerant high pressure fault occurs, and switch S23 is closed when a refrigerant low pressure fault occurs. When any fault switch is closed, the fault signal circuit 200 is turned on, so that the fault relay KA2 is powered to control the fault normally open contact KA2-1 linked to it to be disconnected, and the cold dryer control circuit 100 is cut off to stop the cold dryer.

[0044] The drain valve control circuit 300 is electrically connected to the cold dryer control relay KA1 and the drain valve, respectively, and is used to control the drain valve to open and close when the cold dryer control relay KA1 is powered on and off. Specifically, the drain valve control circuit 300 includes a third contact KA1-3 of the cold dryer control relay and a drain valve control relay KA3 connected in series. The third contact KA1-3 of the cold dryer control relay is connected to the cold dryer control relay KA1, and is used to be linked with the auxiliary contact in the relay KA1 to close when the cold dryer control relay KA1 is powered on, thereby conducting the drain valve control circuit 300, and to be linked with the auxiliary contact in the relay KA1 to disconnect when the cold dryer control relay KA1 is off, thereby disconnecting the drain valve control circuit 300. The drain valve control relay KA3 is used to be electrically connected to the drain valve. The auxiliary contacts in the drain valve control relay KA3 are linked with the main contacts set in the drain valve control circuit. When the drain valve control relay KA3 is energized, the auxiliary contacts are closed, thereby controlling the drain valve to open through the drain valve control circuit; similarly, when the drain valve control relay KA3 loses power, the auxiliary contacts are disconnected, thereby controlling the drain valve to close through the drain valve control circuit.

[0045] The air cooler control circuit 400 is electrically connected to the cold dryer control relay KA1 and the air cooler, respectively, and is used to control the start and stop of the air cooler when the cold dryer control relay KA1 is powered on and off. Specifically, the air cooler control circuit 400 includes the fourth contact KA1-4 of the air cooler control relay and the air cooler control relay KA4 connected in series. The fourth contact KA1-4 of the air cooler control relay is connected to the cold dryer control relay KA1, and is used to be linked with the auxiliary contact in the relay KA1 to close when the cold dryer control relay KA1 is powered on, thereby conducting the air cooler control circuit 400, and to be linked with the auxiliary contact in the relay KA1 to disconnect when the cold dryer control relay KA1 is off, thereby disconnecting the air cooler control circuit 400. The air cooler control relay KA4 is used to be electrically connected to the drain valve. The auxiliary contacts in the air cooler control relay KA4 are linked with the main contacts set in the air cooler control circuit. When the air cooler control relay KA4 is energized, the auxiliary contacts are closed, thereby controlling the start-up of the air cooler through the air cooler control circuit; similarly, when the air cooler control relay KA4 loses power, the auxiliary contacts are disconnected, thereby controlling the shutdown of the air cooler through the air cooler control circuit.

[0046] During the operation of the cold dryer, a large amount of condensed water will be generated. This condensed water needs to be discharged in time, otherwise it will increase the air humidity inside the cold dryer and affect the dehumidification effect of the cold dryer. The condensed water can be discharged to the outside of the equipment by setting a drain valve to keep the inside of the equipment dry. The refrigeration of the cold dryer is achieved by compressing the refrigerant through the cold air machine, and then expanding it to release heat, thereby lowering the temperature.

[0047] After the cold dryer control circuit 100 is turned on, the cold dryer control relay KA1 is energized, and the cold dryer control relay KA1 is linked with the third contact KA1-3 and the fourth contact KA1-4 of the cold dryer control relay respectively, and at the same time the drain valve control circuit 300 and the cold air fan control circuit 400 are turned on, thereby starting the drain valve and the cold air fan.

[0048] For example, Figure 1 As shown, the cold dryer local start and stop module M1 includes a local start normally closed contact S1 and a local stop normally open contact S2 connected in series. Specifically, a local start button and a local stop button are respectively provided on the local start normally closed contact S1 and the local stop normally open contact S2. When the local start button is pressed, the local start normally closed contact S1 is closed, and the cold dryer control circuit 100 is turned on; when the local stop button is pressed, the local stop normally open contact S2 is disconnected, and the cold dryer control circuit 100 is cut off.

[0049] For example, Figure 1As shown, the cold dryer control circuit 100 is also connected in series with a local / remote switch SA1 and a cold dryer remote start / stop module M2 connected in parallel with the cold dryer local start / stop module M1. The local / remote switch SA1 is used to selectively connect to the cold dryer local start / stop module M1 or the cold dryer remote start / stop module M2. The local / remote switch SA1 can be a single-pole double-throw switch or a linkage switch, connecting one of the cold dryer local start / stop module M1 and the cold dryer remote start / stop module M2 to the live wire L, so that only one of the two is connected to the circuit at the same time, so that the cold dryer control circuit 100 can only be controlled by one of the cold dryer local start / stop module M1 and the cold dryer remote start / stop module M2 at the same time. The cold dryer remote start / stop module M2 includes a remote start normally closed contact S3 and a remote stop normally open contact S4 connected in series. The remote start normally closed contact S3 and the remote stop normally open contact S4 can be remotely controlled by DCS respectively. When the local / remote switching switch SA1 is connected to the cold dryer remote start and stop module M1 and the remote start normally closed contact S3 is closed, the cold dryer control circuit 100 is turned on; when the local / remote switching switch SA1 is connected to the cold dryer remote start and stop module M1 and the remote stop normally open contact S4 is disconnected, the cold dryer control circuit 100 is cut off.

[0050] For example, Figure 1 As shown, the cold dryer local start-stop module M1 further includes a cold dryer control relay first contact KA1-1 connected in parallel with the local start normally closed contact S1; the cold dryer remote start-stop module M2 further includes a cold dryer control relay second contact KA1-2 connected in parallel with the remote start normally closed contact S3. The cold dryer control relay first contact KA1-1 and the cold dryer control relay second contact KA1-2 are respectively connected to the cold dryer control relay KA1, and are used to close when the cold dryer control relay KA1 is energized, and to open when the cold dryer control relay KA1 is de-energized. When the cold dryer needs to be started and the local start normally closed contact S1 or the remote start normally closed contact S3 is closed, the cold dryer control relay KA1 is energized to control the closure of the first contact KA1-1 and the second contact KA1-2 of the cold dryer control relay, forming a self-holding cold dryer start. There is no need to continuously press the local start button or continuously output the remote start signal, and the subsequent operation of the local start button or remote start signal can be shielded to avoid interference with the operation of the cold dryer.

[0051] For example, Figure 1As shown, the drain valve control circuit 300 is also connected in series with a timing switch S31. The timing switch S31 is used to close when the third contact KA1-3 of the cold dryer control relay is closed, and to open after a predetermined time. The timing switch is set to control the on and off of the drain valve control circuit 300 at a certain time interval, so that the drain valve is opened regularly to drain water during the operation of the cold dryer.

[0052] For example, Figure 1 As shown, the control circuit of the cold dryer in the thermal power plant also includes an operation signal circuit 500. The operation signal circuit 500 includes the fifth contact KA1-5 of the cold dryer control relay and the operation signal light L1 connected in series, and the DCS operation signal sending module M3 connected in parallel with the operation signal light L1. The fifth contact KA1-5 of the cold dryer control relay is connected to the cold dryer control relay KA1, and is used to close when the cold dryer control relay KA1 is energized and disconnect when the cold dryer control relay KA1 is de-energized. Specifically, the fifth contact KA1-5 of the cold dryer control relay is a normally closed contact. When the cold dryer control circuit 100 is turned on to start the cold dryer, the fifth contact KA1-5 of the cold dryer control relay KA1 is closed, so that the operation signal light L1 is energized and lights up, and the DCS operation signal sending module M3 is energized to send an operation signal to the DCS, prompting on-site and remote personnel that the cold dryer is currently in operation.

[0053] For example, Figure 1 As shown, the thermal power plant cold dryer control circuit also includes a shutdown signal circuit 600. The shutdown signal circuit 600 includes the sixth contact KA1-6 of the cold dryer control relay and the shutdown signal lamp L2 connected in series, and a DCS shutdown signal sending module M4 connected in parallel with the shutdown signal lamp L2. The sixth contact KA1-6 of the cold dryer control relay is connected to the cold dryer control relay KA1, and is used to be disconnected when the cold dryer control relay KA1 is energized and closed when the cold dryer control relay KA1 is de-energized. Specifically, the sixth contact KA1-6 of the cold dryer control relay is a normally open contact. When the cold dryer control circuit 100 is turned on to start the cold dryer, the sixth contact KA1-6 of the cold dryer control relay KA1 is disconnected, and the stop signal light L2 and the DCS stop signal sending module M4 are in a power-off state; and when the cold dryer control circuit 100 is disconnected and the cold dryer is shut down, the cold dryer control relay KA1 loses power, causing the sixth contact KA1-6 of the cold dryer control relay to close, thereby energizing the stop signal light L2 and lighting up, and the DCS stop signal sending module M4 is energized to send a stop signal to the DCS, prompting on-site and remote personnel that the cold dryer is currently in a shutdown state.

[0054] For example, Figure 1As shown, the fault signal circuit 200 also includes a fault signal lamp L3 connected in parallel with the fault relay KA2. When the dryer fails and the fault signal circuit 200 is turned on, the fault signal lamp L3 lights up, prompting the on-site personnel that the dryer is currently in a fault state. The fault relay KA2 is also used to be electrically connected to the DCS fault signal sending module. When the fault relay KA2 is energized, it controls the DCS fault signal sending module to send a DCS fault signal, prompting the remote personnel that the dryer is currently in a fault state.

[0055] It can be understood that the above-mentioned operation signal light L1, shutdown signal light L2 and fault signal light L3 can be set to different colors respectively, for example, the operation signal light L1 is red, the shutdown signal light L2 is green, and the fault signal light L3 is yellow, so as to clearly distinguish and indicate different meanings of on-site signals.

[0056] A control circuit for a cold dryer in a thermal power plant according to an embodiment of the present disclosure is constructed by using simple electrical components, has low cost, high reliability, simple maintenance process, and is easy to operate. It can replace a professional microcontroller or be used as a backup while achieving normal operation of the cold dryer and monitoring of its operating status, and has high applicability.

[0057] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A control circuit for a cold dryer in a thermal power plant, characterized in that: The circuit comprises: The cold dryer control circuit includes a cold dryer local start-stop module, a cold dryer control relay and a fault normally open contact connected in series; wherein the cold dryer local start-stop module is used to turn on or off the cold dryer control circuit; A fault signal circuit, used to be turned on when the cold dryer fails; the fault signal circuit includes a fault relay connected to the fault normally open contact, and the fault relay is used to control the fault normally open contact to be disconnected when powered; A drain valve control circuit is electrically connected to the cold dryer control relay and the drain valve, respectively, and is used to control the drain valve to open and close when the cold dryer control relay is powered on and off; The air cooler control circuit is electrically connected to the cold dryer control relay and the air cooler, and is used to control the start and stop of the air cooler when the cold dryer control relay is energized or de-energized.

2. The control circuit of the cold dryer of a thermal power plant according to claim 1, characterized in that: The local start-stop module of the cold dryer comprises a local start normally closed contact and a local stop normally open contact connected in series; When the local start-up normally closed contact is closed, the cold dryer control circuit is connected; when the local stop-operation normally open contact is disconnected, the cold dryer control circuit is disconnected.

3. The control circuit of the cold dryer of a thermal power plant according to claim 2, characterized in that: The cold dryer control circuit is also connected in series with a local / remote switch and also includes a cold dryer remote start / stop module connected in parallel with the cold dryer local start / stop module; The local / remote switching switch is used to selectively connect to the local start / stop module of the cold dryer or the remote start / stop module of the cold dryer; The remote start and stop module of the cold dryer includes a remote start normally closed contact and a remote stop normally open contact connected in series; When the local / remote switching switch is connected to the remote start / stop module of the cold dryer and the remote start normally closed contact is closed, the cold dryer control circuit is turned on; when the local / remote switching switch is connected to the remote start / stop module of the cold dryer and the remote stop normally open contact is disconnected, the cold dryer control circuit is cut off.

4. The control circuit of the cold dryer of a thermal power plant according to claim 3, characterized in that: The cold dryer local start-stop module further includes a cold dryer control relay first contact connected in parallel with the local start normally closed contact; the cold dryer remote start-stop module further includes a cold dryer control relay second contact connected in parallel with the remote start normally closed contact; The first contact of the cold dryer control relay and the second contact of the cold dryer control relay are respectively connected to the cold dryer control relay, and are used to close when the cold dryer control relay is energized and to open when the cold dryer control relay is de-energized.

5. The control circuit of the cold dryer of a thermal power plant according to claim 1, characterized in that: The drain valve control circuit includes a third contact of a cold dryer control relay and a drain valve control relay connected in series; The third contact of the cold dryer control relay is connected to the cold dryer control relay, and is used to close when the cold dryer control relay is powered on, and to open when the cold dryer control relay is powered off; The drain valve control relay is used to be electrically connected to the drain valve; when the drain valve control relay is energized, the drain valve is controlled to be opened, and when the drain valve control relay is de-energized, the drain valve is controlled to be closed.

6. The control circuit of the cold dryer of a thermal power plant according to claim 5, characterized in that: The drain valve control circuit is also connected in series with a timing switch; The timing switch is used to close when the third contact of the cold dryer control relay is closed, and to open after a predetermined time has passed.

7. The control circuit of the cold dryer of a thermal power plant according to claim 1, characterized in that: The air cooler control circuit comprises a fourth contact of the cold dryer control relay and an air cooler control relay connected in series with each other; The fourth contact of the cold dryer control relay is connected to the cold dryer control relay, and is used to close when the cold dryer control relay is powered on, and to open when the cold dryer control relay is powered off; The air cooler control relay is used to be electrically connected to the air cooler; when the air cooler control relay is energized, the air cooler is controlled to start, and when the air cooler control relay is de-energized, the air cooler is controlled to stop.

8. The control circuit of a cold dryer in a thermal power plant according to any one of claims 1 to 7, characterized in that: The thermal power plant cold dryer control circuit also includes an operation signal circuit; The operation signal circuit includes a fifth contact of the cold dryer control relay and an operation signal light connected in series, and a DCS operation signal sending module connected in parallel with the operation signal light; The fifth contact of the cold dryer control relay is connected to the cold dryer control relay, and is used for closing when the cold dryer control relay is energized and opening when the cold dryer control relay is de-energized.

9. The control circuit of a cold dryer in a thermal power plant according to any one of claims 1 to 7, characterized in that: The thermal power plant cold dryer control circuit also includes a shutdown signal circuit; The shutdown signal circuit includes a sixth contact of the cold dryer control relay and a shutdown signal light connected in series, and a DCS shutdown signal sending module connected in parallel with the shutdown signal light; The sixth contact of the cold dryer control relay is connected to the cold dryer control relay, and is used for opening when the cold dryer control relay is energized and closing when the cold dryer control relay is de-energized.

10. The control circuit of a cold dryer in a thermal power plant according to any one of claims 1 to 7, characterized in that: The fault signal circuit also includes a fault signal lamp connected in parallel with the fault relay; The fault relay is also used to be electrically connected to a DCS fault signal sending module; when the fault relay is energized, the DCS fault signal sending module is controlled to send a DCS fault signal.

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