Transformer cooler self-starting system and method during PLC fault

Abstract

The invention relates to the technical field of oil-immersed transformer cooling, in particular to a transformer cooler self-starting system and method in PLC fault, and the system is characterized in that the output end of a PLC system is connected with the input end of a PLC fault detection and cooler starting module; the output end of the PLC fault detection and cooler starting module is connected with the input end of the cooler control loop module, the cooler control loop module is connected with the control input ends of the cooler # 1, the cooler # 2, the cooler # 3 and the cooler # 4, and the oil circulation ends of the cooler # 1, the cooler # 2, the cooler # 3 and the cooler # 4 are connected with the oil circulation end of the main transformer. The state output ends of the cooler # 1, the cooler # 2, the cooler # 3 and the cooler # 4 are respectively connected with the input end of the cooler full-stop monitoring module, and the output end of the cooler full-stop monitoring module is connected with the input end of the monitoring system. According to the invention, the reliability and safety of the system are effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil-immersed transformer cooling, and in particular to a transformer cooler self-starting system and method when a PLC fails. Background Art

[0002] Large oil-immersed transformers usually use forced oil circulation air cooling as a cooling method. With the development of science and technology, most transformer cooling control systems use PLC control. However, once the PLC system fails or loses power, the transformer cooler will stop operating and cannot be cooled normally, causing the transformer temperature to continue to rise, which may cause tripping or burning accidents. Therefore, it is very important to realize the automatic start function of the cooler in the event of a PLC failure or power failure. At present, traditional technology mainly relies on the operation monitoring relay contacts inside the PLC device to reflect abnormal conditions. However, this method has obvious defects: when the program inside the PLC stops running or gets stuck, the subsequent process cannot be continued, resulting in the shutdown of all transformer coolers. More seriously, since the PLC device cannot accept any commands or issue abnormal alarm signals, the system cannot send alarm information such as "cooler all stopped" or "PLC failure" to the PLC touch screen or remote operation monitoring personnel, making it impossible for the operator to judge the operating status of the cooler in time, and unable to take necessary treatment measures, increasing the risk of safe operation of the equipment. Summary of the invention

[0003] The purpose of the present invention is to provide a self-starting system and method for a transformer cooler when a PLC fails. By adding additional hardware logic and monitoring circuits in the control system, the automatic starting function of the cooler when a PLC fails or loses power is realized, and a hard contact alarm function for a complete stop of the cooler is provided. The application of the present invention not only improves the reliability and safety of the system, but also enables the operating personnel to be aware of the operating status of the cooler in a timely manner, effectively preventing serious accidents caused by PLC failures.

[0004] The present invention is achieved through the following technical solutions:

[0005] A transformer cooler self-starting system in case of a PLC fault, comprising: a PLC system, a PLC fault detection and cooler start module, a cooler control loop module, cooler #1, cooler #2, cooler #3, cooler #4, a cooler full stop monitoring module, a monitoring system and a main transformer; the output end of the PLC system is connected to the input end of the PLC fault detection and cooler start module, the output end of the PLC fault detection and cooler start module is connected to the input end of the cooler control loop module, and the cooler control loop module is respectively connected to the control input end of the cooler #1 The control input end of cooler #1, the control input end of cooler #2, the control input end of cooler #3, and the control input end of cooler #4 are connected; the oil circulation end of cooler #1, the oil circulation end of cooler #2, the oil circulation end of cooler #3, and the oil circulation end of cooler #4 are respectively connected to the oil circulation end of the main transformer; the status output end of cooler #1, the status output end of cooler #2, the status output end of cooler #3, and the status output end of cooler #4 are respectively connected to the input end of the cooler full stop monitoring module; the output end of the cooler full stop monitoring module is connected to the input end of the monitoring system.

[0006] Optionally, the PLC fault detection and cooler start-up module includes: relay K08, relay K017, and relay K01; one end of the coil of the relay K08 is connected to the output end of the PLC system, the other end of the coil of the relay K08 is grounded, the coil of the relay K017 is connected in parallel with the coil of the relay K08, the normally open contacts 5 and 9 of the relay K01 are connected in parallel with the normally closed contacts 1 and 9 of the relay K017, and are connected to the cooler control loop module.

[0007] Optionally, the cooler control loop module includes: relay KA1, relay KM11; one end of the normally open contacts 5, 9 of the relay KA1 is connected to the parallel point of the relay K017 and relay K01, the other end of the normally open contacts 5, 9 of the relay KA1 is connected to one end of the coil of the relay KM11, and the other end of the coil of the relay KM11 is grounded.

[0008] Optionally, the cooler full stop monitoring module includes: relay KM21, relay KM31, relay KM41, relay KM12, relay KM22, relay KM32, relay KM42; a pair of normally closed contacts of relay KM11, relay KM21, relay KM31, relay KM41 are connected in series, a pair of normally closed contacts of relay KM12, relay KM22, relay KM32, relay KM42 are connected in series, one end of the signal line is connected to the end of the series connection of all the normally closed contacts of the relays, and the other end of the signal line is connected to the input end of the monitoring system.

[0009] A method for self-starting a transformer cooler when a PLC fails, which is applied to a self-starting system for a transformer cooler when a PLC fails, the method comprising: a normal operation step of a PLC system and a fault operation step of a PLC system;

[0010] Among them, the normal operation steps of the PLC system are:

[0011] The PLC system sends a normal operation signal to the PLC fault detection and cooler start module, and the PLC fault detection and cooler start module remains in a normal state and does not trigger the cooler start;

[0012] The cooler control loop module operates normally and controls the start and stop of the cooler;

[0013] The cooler full stop monitoring module continuously obtains the operating status of the cooler.

[0014] Optionally, the PLC system fault operation steps are:

[0015] The PLC system stops sending a normal operation signal to the PLC fault detection and cooler start module, and the PLC fault detection and cooler start module triggers a start signal for the cooler;

[0016] The cooler control loop module receives the start signal, the cooler runs, and performs oil circulation exchange with the main transformer;

[0017] The cooler full stop monitoring module continuously obtains the operating status of the cooler. If it detects that the cooler is fully stopped, it sends a full stop alarm signal to the monitoring system.

[0018] Optionally, the operating principle of the cooler full stop monitoring module in the normal operating state of the PLC system is: at least one relay among relay KM11, relay KM21, relay KM31, relay KM41, or relay KM12, relay KM22, relay KM32, and relay KM42 is energized, the normally closed contact loops of the relays connected in series are opened, and the monitoring system does not receive the full stop alarm signal.

[0019] Optionally, the operating principle of the cooler full stop monitoring module in the PLC system fault operation state is: all relays KM11, relay KM21, relay KM31, relay KM41, or relays KM12, relay KM22, relay KM32, relay KM42 are demagnetized, and the normally closed contacts of each relay are closed to form a complete series circuit, which sends a full stop alarm signal to the monitoring system.

[0020] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0021] The present invention realizes the automatic start-up function of the cooler when the PLC fails or loses power by adding additional hardware logic and monitoring circuits in the control system, and provides a hard contact alarm function for the complete stop of the cooler. The application of the present invention not only improves the reliability and safety of the system, but also enables the operating personnel to know the operating status of the cooler in time, effectively preventing serious accidents caused by PLC failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the principle of starting all coolers when a PLC system failure is provided in the present invention;

[0023] Figure 2 A schematic diagram of the principle of the control circuit of cooler #1 provided by the present invention;

[0024] Figure 3 A logic block diagram of the main transformer cooler self-starting system when the PLC system provided by the present invention fails;

[0025] Figure 4 This is a schematic diagram of the cooler full stop signal sent to the LCU monitoring system provided by the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, what is described is only a part of the present invention, not all of it. Generally, the components of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the present invention provides one embodiment: a transformer cooler self-starting system in case of PLC failure, comprising: a PLC system, a PLC fault detection and cooler startup module, a cooler control loop module, cooler #1, cooler #2, cooler #3, cooler #4, a cooler full stop monitoring module, a monitoring system and a main transformer; the output end of the PLC system is connected to the input end of the PLC fault detection and cooler startup module, the output end of the PLC fault detection and cooler startup module is connected to the input end of the cooler control loop module, and the cooler control loop module is connected to the cooler The control input end of cooler #1, the control input end of cooler #2, the control input end of cooler #3, and the control input end of cooler #4 are connected; the oil circulation end of cooler #1, the oil circulation end of cooler #2, the oil circulation end of cooler #3, and the oil circulation end of cooler #4 are respectively connected to the oil circulation end of the main transformer; the status output end of cooler #1, the status output end of cooler #2, the status output end of cooler #3, and the status output end of cooler #4 are respectively connected to the input end of the cooler full stop monitoring module; the output end of the cooler full stop monitoring module is connected to the input end of the monitoring system.

[0028] In this embodiment, the PLC system is divided into a normal operation step and a fault operation step, and the specific determination basis of the fault operation is that the PLC system fails or loses power;

[0029] Specifically, the normal operation steps of the PLC system are:

[0030] The PLC system sends a normal operation signal to the PLC fault detection and cooler start module, and the PLC fault detection and cooler start module remains in a normal state and does not trigger the cooler start;

[0031] The cooler control loop module operates normally and controls the start and stop of the cooler;

[0032] The cooler full stop monitoring module continuously obtains the operating status of the cooler.

[0033] The PLC system fault operation steps are:

[0034] The PLC system stops sending a normal operation signal to the PLC fault detection and cooler start module, and the PLC fault detection and cooler start module triggers a start signal for the cooler;

[0035] The cooler control loop module receives the start signal, the cooler runs, and performs oil circulation exchange with the main transformer;

[0036] The cooler full stop monitoring module continuously obtains the operating status of the cooler. If it detects that the cooler is fully stopped, it sends a full stop alarm signal to the monitoring system.

[0037] In the specific application of this embodiment, the PLC fault detection and cooler start-up module includes: relay K08, relay K017, and relay K01; one end of the coil of the relay K08 is connected to the output end of the PLC system, the other end of the coil of the relay K08 is grounded, the coil of the relay K017 is connected in parallel with the coil of the relay K08, the normally open contacts 5 and 9 of the relay K01 are connected in parallel with the normally closed contacts 1 and 9 of the relay K017, and are connected to the cooler control loop module.

[0038] In practice, this embodiment connects a relay K017 of the same model in parallel to the two end coils of the system switch input "PLC operation" monitoring relay K08 as a relay to monitor whether the PLC is faulty, and uses its normally closed contacts in the control loop. When the PLC is operating normally, both K08 and K017 relays are energized; when the PLC fails or loses power and does not operate, both relays are not energized.

[0039] In a further implementation of this embodiment, the cooler control loop module includes: relay KA1, relay KM11; one end of the normally open contacts 5 and 9 of the relay KA1 is connected to the parallel point of the relay K017 and relay K01, the other end of the normally open contacts 5 and 9 of the relay KA1 is connected to one end of the coil of the relay KM11, and the other end of the coil of the relay KM11 is grounded.

[0040] Take cooler #1 as an example: connect a pair of normally closed contacts 1 and 9 of relay K017 in parallel with a pair of normally open contacts 5 and 9 of relay K01 in the main transformer cooler automatic control circuit. When the PLC operates normally, relay K017 is in an energized state, and the normally closed contacts 1 and 9 of the relay are in an open state, and do not participate in controlling the cooler. When the PLC fails, relay K017 is not energized, and its normally closed contacts 1 and 9 are closed, and the cooler circuit under the "automatic" control mode is connected to start the cooler. The control circuits of the four coolers are implemented in this way to achieve the function of starting all four coolers after a PLC failure.

[0041] More specifically, the cooler full stop monitoring module includes: relay KM21, relay KM31, relay KM41, relay KM12, relay KM22, relay KM32, relay KM42; a pair of normally closed contacts of relay KM11, relay KM21, relay KM31, relay KM41 are connected in series, a pair of normally closed contacts of relay KM12, relay KM22, relay KM32, relay KM42 are connected in series, one end of the signal line is connected to the end of the series connection of all the normally closed contacts of the relays, and the other end of the signal line is connected to the input end of the monitoring system.

[0042] The operating principle of the cooler full stop monitoring module in the normal operating state of the PLC system is: at least one of relays KM11, relay KM21, relay KM31, relay KM41, or relay KM12, relay KM22, relay KM32, relay KM42 is energized, the normally closed contact loops of the relays connected in series are opened, and the monitoring system does not receive a full stop alarm signal.

[0043] The operating principle of the cooler full stop monitoring module in the PLC system fault operation state is: all relays KM11, relay KM21, relay KM31, relay KM41, or relays KM12, relay KM22, relay KM32, relay KM42 are demagnetized, and the normally closed contacts of each relay are closed to form a complete series circuit, which sends a full stop alarm signal to the monitoring system.

[0044] During the specific implementation, a pair of normally closed contacts that control the fan starting relays KM11, KM21, KM31, and KM41 of each cooler are connected in series, or a pair of normally closed contacts that control the starting relays KM12, KM22, KM32, and KM42 of each oil pump are connected in series. This is used as a signal to reflect whether the cooler is completely stopped and connected to the monitoring system to realize the hard contact alarm function of the cooler being completely stopped, so as to prevent the PLC from being unable to send a cooler complete stop signal to the monitoring system, which affects the timely handling of the operation and maintenance personnel and causes a larger fault.

[0045] When the PLC system crashes or loses power, the main transformer power signal is normal, and cooler No. X is in the "automatic" operation mode. The main transformer cooling control system will automatically start all coolers in automatic mode.

[0046] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A self-starting system for transformer cooler in case of PLC failure, characterized in that: include: PLC system, PLC fault detection and cooler start-up module, cooler control loop module, cooler #1, cooler #2, cooler #3, cooler #4, cooler full stop monitoring module, monitoring system and main transformer; the output end of the PLC system is connected to the input end of the PLC fault detection and cooler start-up module, the output end of the PLC fault detection and cooler start-up module is connected to the input end of the cooler control loop module, and the cooler control loop module is respectively connected to the control input end of the cooler #1, the control input end of the cooler #2, and the control input end of the cooler #3. The input end of the cooler full stop monitoring module is connected to the control input end of cooler #3 and the control input end of cooler #4. The oil circulation ends of cooler #1, cooler #2, cooler #3 and cooler #4 are respectively connected to the oil circulation end of the main transformer. The status output end of cooler #1, cooler #2, cooler #3 and cooler #4 are respectively connected to the input end of the cooler full stop monitoring module. The output end of the cooler full stop monitoring module is connected to the input end of the monitoring system.

2. The transformer cooler self-starting system when PLC fails according to claim 1, characterized in that: The PLC fault detection and cooler start-up module includes: relay K08, relay K017, and relay K01; one end of the coil of the relay K08 is connected to the output end of the PLC system, the other end of the coil of the relay K08 is grounded, the coil of the relay K017 is connected in parallel with the coil of the relay K08, the normally open contacts 5 and 9 of the relay K01 are connected in parallel with the normally closed contacts 1 and 9 of the relay K017, and are connected to the cooler control loop module.

3. The transformer cooler self-starting system when PLC fails according to claim 2 is characterized in that: The cooler control loop module includes: relay KA1 and relay KM11; one end of the normally open contacts 5 and 9 of the relay KA1 is connected to the parallel point of the relay K017 and relay K01, the other end of the normally open contacts 5 and 9 of the relay KA1 is connected to one end of the coil of the relay KM11, and the other end of the coil of the relay KM11 is grounded.

4. The transformer cooler self-starting system when PLC fails according to claim 3 is characterized in that: The cooler full stop monitoring module includes: relay KM21, relay KM31, relay KM41, relay KM12, relay KM22, relay KM32, relay KM42; a pair of normally closed contacts of each of the relays KM11, relay KM21, relay KM31, relay KM41 are connected in series, a pair of normally closed contacts of each of the relays KM12, relay KM22, relay KM32, relay KM42 are connected in series, one end of the signal line is connected to the end of the series connection of the normally closed contacts of all the relays, and the other end of the signal line is connected to the input end of the monitoring system.

5. A method for self-starting a transformer cooler when a PLC fails, which is applied to the self-starting system for a transformer cooler when a PLC fails as claimed in any one of claims 1 to 4, characterized in that: The method comprises: a PLC system normal operation step and a PLC system fault operation step; Among them, the normal operation steps of the PLC system are: The PLC system sends a normal operation signal to the PLC fault detection and cooler start module, and the PLC fault detection and cooler start module remains in a normal state and does not trigger the cooler start; The cooler control loop module operates normally and controls the start and stop of the cooler; The cooler full stop monitoring module continuously obtains the operating status of the cooler.

6. The method for self-starting a transformer cooler when a PLC fails according to claim 5, characterized in that: The PLC system fault operation steps are: The PLC system stops sending a normal operation signal to the PLC fault detection and cooler start module, and the PLC fault detection and cooler start module triggers a start signal for the cooler; The cooler control loop module receives the start signal, the cooler runs, and performs oil circulation exchange with the main transformer; The cooler full stop monitoring module continuously obtains the operating status of the cooler. If it detects that the cooler is fully stopped, it sends a full stop alarm signal to the monitoring system.

7. The method for self-starting a transformer cooler when a PLC fails according to claim 6, characterized in that: The operating principle of the cooler full stop monitoring module in the normal operating state of the PLC system is: at least one of relays KM11, relay KM21, relay KM31, relay KM41, or relay KM12, relay KM22, relay KM32, relay KM42 is energized, the normally closed contact loops of the relays connected in series are opened, and the monitoring system does not receive a full stop alarm signal.

8. The method for self-starting a transformer cooler when a PLC fails according to claim 7, characterized in that: The operating principle of the cooler full stop monitoring module in the PLC system fault operation state is: all relays KM11, relay KM21, relay KM31, relay KM41, or relays KM12, relay KM22, relay KM32, relay KM42 are demagnetized, and the normally closed contacts of each relay are closed to form a complete series circuit, which sends a full stop alarm signal to the monitoring system.

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