Transformer cooler redundancy control system and method based on two paths of RS485

Abstract

The invention belongs to the technical field of transformer on-line monitoring, and particularly relates to a transformer cooler redundancy control system based on double RS485, which comprises a touch screen A, a touch screen B, a monitoring system A and a monitoring system B, wherein the touch screen A is connected with the monitoring system A, and the touch screen B is connected with the monitoring system B; the monitoring system A is respectively connected with the control center A, the control center B and the transformer cooler which are used as a substation control background, and the monitoring system B is respectively connected with the control center A, the control center B and the transformer cooler. According to the cooler monitoring device, an independent arbitration execution system is not arranged, only two identical core monitoring systems composed of hardware are adopted to form the cooler monitoring device, the two monitoring systems conduct information interaction in an RS485 dual-channel mode, and the dual redundancy mode provides dual guarantees for converter transformer cooler control.

Description

Technical Field

[0001] The invention belongs to the technical field of transformer online monitoring, in particular to a transformer cooler redundant control system and method based on dual-channel RS485. Background Art

[0002] As the core equipment for AC / DC conversion in converter stations, the safety and reliability of converter transformers are crucial to the entire DC transmission project. High heat dissipation is a prerequisite for ensuring the stable operation of converter transformers. Usually, local control cabinets are configured in converter stations to intelligently monitor the coolers.

[0003] At present, most of the related monitoring devices of domestic manufacturers adopt redundant control design, which consists of two core monitoring systems and one arbitration execution system. The two core monitoring systems simultaneously collect sensor signals and analyze the control logic of the cooler. The arbitration execution system is connected to the two core monitoring systems respectively, and performs real-time master-slave arbitration on the two monitoring systems, while executing the cooler control decision of the main monitoring system. Due to the complex structure of this mode, the production and maintenance costs of the product also increase significantly. The most fatal flaw is that when the arbitration execution system fails, the "redundant control" mode completely loses its effectiveness, and the entire cooler control system will not work properly. Summary of the invention

[0004] The purpose of the present invention is to provide a transformer cooler redundant control method based on dual-channel RS485 communication. The dual redundant system construction mode of "dual-core monitoring system" + "dual-channel RS485 communication" is adopted to simplify the hardware composition of the transformer cooler monitoring system, reduce the implementation cost, and improve the reliability of the cooler monitoring system.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a transformer cooler redundant control system based on dual-channel RS485, characterized in that it includes: a touch screen A, a touch screen B, a monitoring system A and a monitoring system B;

[0006] Among them, touch screen A is connected to monitoring system A, and touch screen B is connected to monitoring system B;

[0007] The monitoring system A is respectively connected to the control center A, the control center B and the transformer cooler as the control background of the substation, and the monitoring system B is respectively connected to the control center A, the control center B and the transformer cooler.

[0008] The monitoring system A and the monitoring system B have the same structure, and both include: a main processor unit and an RS485 communication module connected to the main processor unit, an analog quantity acquisition module, a switch quantity input module, and an export control module;

[0009] The main processor unit is used to obtain the signals from the analog acquisition module and the switch input module and perform data analysis to calculate the current transformer oil level temperature, winding temperature and load percentage, and send the obtained control decision instructions to the export control module in real time according to the preset value of the cooler start / stop threshold and the control logic;

[0010] RS485 communication module, used for serial communication with the RS485 communication module in the corresponding monitoring system; touch screen A is connected to monitoring system A through the RS485 communication module of monitoring system A, and touch screen B is connected to monitoring system B through the RS485 communication module of monitoring system B, used for displaying system information;

[0011] The analog quantity acquisition module is used to acquire the analog quantity signal of the basic data of the transformer detected by the sensor arranged on the transformer;

[0012] The switch input module is used to collect the status signal of the transformer cooler from the transformer front-end control cabinet, control center A and control center B;

[0013] The export control module is used to receive the control decision instruction sent by the main processor unit, and control the transformer cooler according to the control decision instruction. The export control module is activated to control the start and stop of the cooler.

[0014] The analog signals of the transformer basic data include: oil surface temperature signal, winding temperature signal, and grid-side bushing current signal;

[0015] The status signals include: transformer fan start and stop, oil flow switch, protection cut signal, switch gear signal, manual automatic control signal, forced reset signal and protection cut reset signal.

[0016] The monitoring system A and the monitoring system B communicate with the control center A or the control center B respectively using the IEC61850 communication protocol.

[0017] The control method of the transformer cooler redundant control system based on dual-channel RS485 includes the following steps:

[0018] 1) According to the master-slave arbitration mechanism, monitoring system A and monitoring system B perform master-slave switching;

[0019] 2) The analog quantity acquisition module collects the oil level temperature signal, winding temperature signal and grid-side bushing current signal in real time, and sends the analog signal of the transformer basic data to the main processor unit;

[0020] 3) The switch input module collects the status signal of the transformer cooler from the transformer front-end control cabinet, control center A and control center B;

[0021] 4) The main processor unit obtains the signals from the analog quantity acquisition module and the switch quantity input module and performs data analysis, calculates the current transformer oil level temperature, winding temperature and load percentage, and analyzes the transformer cooler according to the control logic priority to obtain control decision instructions, and sends the obtained control decision instructions to the export control module in real time;

[0022] 5) The export control module receives the control decision instruction sent by the main processor unit, and controls the transformer cooler according to the control decision instruction. The export control module operates to control the start and stop of the cooler.

[0023] According to the master-slave arbitration mechanism, monitoring system A and monitoring system B perform master-slave switching, specifically:

[0024] The monitoring system A and the monitoring system B use the following arbitration mechanism to perform active / standby switching:

[0025] 1-1) Device startup phase: When the working status is normal, the monitoring system A is the main side by default;

[0026] 1-2) System operation stage: If the monitoring system B on the standby side still determines that more groups of coolers need to be started after waiting for the main side cooler to adjust the set time, the main side and the standby side are switched;

[0027] 1-3) System abnormality stage: If the monitoring system A on the active side is in an abnormal working state, and the monitoring system B on the standby side is in normal working state, the active-standby switch will be performed, and the original default monitoring system A will become the standby side, and the original standby side monitoring system B will become the active side;

[0028] 1-4) The monitoring system A is connected to the monitoring system B via the first communication channel and the second communication channel;

[0029] When the first communication channel and the second communication channel are both disconnected, and the monitoring system A and the monitoring system B are both working normally, the two monitoring systems are switched to the master side, and the combined set is taken to jointly control the transformer cooler.

[0030] In step 4), the transformer cooler is analyzed according to the control logic priority to obtain control decision instructions, including: manual control logic, protection cut control logic, abnormal control logic, forced control logic, periodic rotation control logic, and automatic control logic from high to low priority;

[0031] The manual control logic is used for the transformer cooler monitoring device to exit control after receiving a manual signal;

[0032] The protection cut control logic is used to cut off all coolers when the transformer protection trips. The protection cut command needs to be reset locally in the transformer cooler monitoring device cabinet. The primary and standby monitoring systems exchange protection cut events and times through serial communication to achieve synchronization of the protection cut command and reset signal.

[0033] The abnormal control logic is used to delay the start of all coolers between groups when analog quantity collection abnormalities or power failure occur in both monitoring systems;

[0034] The forced control logic is used to receive the forced command from the control center to realize forced start or forced stop control of the cooler by group. The forced command needs to be reset locally in the transformer cooler monitoring device cabinet; the main side and standby side monitoring systems exchange forced events and times through serial communication to realize the action synchronization of forced commands and reset signals;

[0035] The periodic rotation control logic is used to periodically rotate and start a group of coolers with the shortest running time and stop a group of coolers with the longest running time, and the primary side and standby side monitoring systems synchronize the actions of cooler control through serial communication;

[0036] The automatic control logic is used to configure the oil temperature, winding temperature and transformer load to realize automatic start and stop control of the cooler according to the set value; when the main side monitoring system performs the start and stop control of the cooler, the relevant information is transmitted through serial communication, and the standby side synchronizes with the main side monitoring system to output the control signal of the corresponding cooler, so as to realize the synchronous connection of the standby side to the cooler control when the main side is powered off. The present invention has the following beneficial effects and advantages:

[0037] The transformer cooler redundant control method based on dual-channel RS485 communication of the present invention does not set up a separate arbitration execution system, but only adopts two core monitoring systems with exactly the same hardware composition to form a cooler monitoring device. The two monitoring systems use the RS485 dual-channel mode to exchange information. This "dual redundancy" mode provides double protection for the control of the converter transformer cooler, which can effectively improve the safety of transformer operation. At the same time, by simplifying the system structure of the traditional transformer cooler monitoring device, the product production and maintenance costs are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The system composition and principle diagram of the present invention;

[0039] Among them, in the figure: 1 is monitoring system A, 2 is monitoring system B, 3 is touch screen A, 4 is touch screen B, 5 is power module, 6 is main processor unit, 7 is RS485 communication module, 8 is analog quantity acquisition module, 9 is switch quantity input module, 10 is output control module;

[0040] Figure 2 A schematic diagram of the cooler control logic priority of the control method of the present invention. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0042] like Figure 1 As shown, it is a schematic diagram of the system composition and principle of the invention;

[0043] (1) System composition

[0044] 1) The system composition of the control method proposed in this patent includes: monitoring system A1, monitoring system B2, touch screen A3, touch screen B4. The hardware composition of the two monitoring systems is the same, including: power module 5, main processor unit 6, RS485 communication module 7, analog quantity acquisition module 8, switch quantity input module 9, and export control module 10.

[0045] The system composition of the control method proposed in the present invention includes: touch screen A3, touch screen B4, monitoring system A1 and monitoring system B2;

[0046] Among them, touch screen A3 is connected to monitoring system A1, and touch screen B4 is connected to monitoring system B2;

[0047] The monitoring system A1 is respectively connected to the control center A, the control center B and the transformer cooler as the control background of the substation, and the monitoring system B2 is respectively connected to the control center A, the control center B and the transformer cooler.

[0048] (2) The monitoring system A1 and the monitoring system B2 have the same structure, and both include: a main processor unit 6, and an RS485 communication module 7 connected to the main processor unit 6, an analog quantity acquisition module 8, a switch quantity input module 9, and an outlet control module 10;

[0049] The main processor unit 6 is used to obtain the signals of the analog acquisition module and the switch input module and perform data analysis to calculate the current transformer oil level temperature, winding temperature and load percentage, and according to the preset value of the cooler start / stop threshold and the control logic, the obtained control decision instruction is sent to the outlet control module 10 in real time;

[0050] RS485 communication module 7, used for serial communication with the RS485 communication module in the corresponding monitoring system; touch screen A3 is connected to monitoring system A1 through the RS485 communication module of monitoring system A1, and touch screen B4 is connected to monitoring system B2 through the RS485 communication module of monitoring system B2, used for displaying system information;

[0051] RS485 communication module 7 provides at least 8 RS485 hardware interfaces;

[0052] The analog quantity acquisition module 8 is used to collect the analog quantity signal of the basic data of the transformer detected by the sensor set on the transformer; the analog quantity acquisition module 8 can collect at least 8 channels of 4-20mA current; the switch quantity input module can input at least 32 channels of switch quantities; the output control module can output at least 24 channels of switch quantities;

[0053] The switch input module 9 is used to collect the status signal of the transformer cooler from the transformer front-end control cabinet, control center A and control center B;

[0054] The outlet control module 10 is used to receive the control decision instruction sent by the main processor unit 6, and control the transformer cooler according to the control decision instruction. The outlet control module is activated to control the start and stop of the cooler.

[0055] (3) The analog signals of transformer basic data include: oil level temperature signal, winding temperature signal, and grid-side bushing current signal;

[0056] Status signals include: transformer fan start and stop, oil flow switch, protection cut signal, switch gear signal, manual automatic control signal, forced reset signal and protection cut reset signal.

[0057] (4) The control method of the transformer cooler redundant control system based on dual-channel RS485 communication of the present invention comprises the following steps:

[0058] 1) According to the master-slave arbitration mechanism, monitoring system A1 and monitoring system B2 perform master-slave switching;

[0059] 2) The analog quantity acquisition module 8 collects the oil surface temperature signal, the winding temperature signal and the grid-side bushing current signal in real time, and sends the analog signal of the transformer basic data to the main processor unit 6;

[0060] 3) The switch input module 9 collects the status signal of the transformer cooler from the transformer front-end control cabinet, control center A and control center B;

[0061] 4) The main processor unit 6 obtains the signals from the analog quantity acquisition module and the switch quantity input module and performs data analysis, calculates the current transformer oil level temperature, winding temperature and load percentage, and analyzes the transformer cooler according to the control logic priority to obtain the control decision instruction, and sends the obtained control decision instruction to the export control module 10 in real time;

[0062] 5) The outlet control module 10 receives the control decision instruction sent by the main processor unit 6, and controls the transformer cooler according to the control decision instruction. The outlet control module operates to control the start and stop of the cooler.

[0063] The power supply module of the control method proposed in the present invention provides two power supply inputs, one of which is an AC voltage input and the other is a DC voltage input; the main processor unit provides at least 2 Gigabit Ethernet optical ports and 1 100M Ethernet electrical port, and supports the IEC61850 communication protocol; wherein the monitoring system A1 and the monitoring system B2 communicate with the control center A or the control center B respectively using the IEC61850 communication protocol.

[0064] (5) In the transformer cooler redundant control method based on dual-channel RS485 communication proposed in the present invention, monitoring system A and monitoring system B perform serial communication and data exchange through their respective communication modules using two RS485 interfaces to achieve master-slave switching and information synchronization of the two monitoring systems.

[0065] (6) Dual-channel RS485 communication mode

[0066] In the control method proposed in this patent, monitoring system A and monitoring system B communicate serially through two RS485 interfaces via RS485 communication modules to achieve data exchange and information synchronization. According to the data information that the system needs to transmit, the hexadecimal transmission mode is adopted to communicate according to the message structure shown in the table below.

[0067]

[0068] The message consists of a header, message type (receive / send), system parameters, checksum and trailer. The checksum is the sum of the message type and each data item in the system parameters, which is used to verify the integrity and accuracy of the data in the communication.

[0069] By default, communication channel 1 is used to conduct serial communication in a mode where monitoring system A actively sends and monitoring system B parses and replies. It provides communication fault detection and channel switching functions. When the received message byte length or checksum is wrong, it is judged as a communication channel disconnection, and it is immediately displayed on the touch screen and reported to control center A and control center B; when communication channel 1 is disconnected, if channel 2 is normal, the system will automatically switch to channel 2 for serial communication. This "dual-channel RS485 communication" method can greatly improve the reliability of the cooler monitoring device.

[0070] (7) Master-slave arbitration mechanism

[0071] In the transformer cooler redundant control method based on dual-channel RS485 communication proposed in this patent, monitoring systems A and B use the following arbitration mechanism to perform active-standby switching:

[0072] 1) Device startup phase: When the working status of the system on this side is normal, the monitoring system on the other side is the primary side, and the other side is the backup side. When the working status of the system on this side is normal, the monitoring system A is the primary side by default.

[0073] 2) System operation stage: If the standby side still determines that more groups of coolers need to be started after waiting for the main side cooler to adjust for 3 minutes, the main side and the standby side will be switched.

[0074] 3) System abnormality stage: If the working status of the active side system is abnormal and the working status of the standby side system is normal, the active-standby switching will be performed, and the original active side will become the standby side, and the original standby side will become the active side.

[0075] The cooler outlet control of monitoring system A and monitoring system B is in parallel. When communication channel 1 and communication channel 2 are both disconnected, if the working status of monitoring system A and B are normal, both monitoring systems will become the master side and take the union to jointly control the cooler.

[0076] (8) System control logic

[0077] In the control method proposed in this patent, the monitoring process of the cooler includes the following control logic:

[0078] 1) Manual control logic: After receiving the manual signal, the transformer cooler monitoring device exits the control and each group of coolers can be switched on and off locally.

[0079] 2) Protection cut-off control logic: When the transformer protection trips, all coolers are cut off, and the protection cut-off command needs to be reset locally in the transformer cooler monitoring device cabinet. The primary and standby monitoring systems exchange protection cut-off events and times through serial communication to achieve synchronization of the protection cut-off command and reset signal.

[0080] 3) Abnormal control logic: When analog quantity acquisition abnormalities or power failure occur in both monitoring systems, all coolers will be started with a delay between groups.

[0081] 4) Forced control logic: Adopt IEC61850 communication protocol to receive the forced command from the control center to realize forced start or forced stop control of the cooler by group. The forced command needs to be reset locally in the transformer cooler monitoring device cabinet. The main side and standby side monitoring systems exchange forced events and time through serial communication to realize the synchronization of the action of forced commands and reset signals.

[0082] 5) Cycle rotation control logic: Cycle rotation starts a group of transformer coolers with the shortest running time and stops a group of coolers with the longest running time. The primary and standby monitoring systems synchronize the cooler control actions through serial communication.

[0083] 6) Automatic control logic: Three modes of configuration are available: oil temperature, winding temperature, and transformer load, to achieve automatic start and stop control of the cooler according to a set value. When the main-side monitoring system starts and stops the cooler, the relevant information is transmitted through serial communication, and the standby side follows and outputs the control signal of the corresponding cooler synchronously on the main side, so as to achieve synchronous connection of the standby side's control of the cooler in the event of a power outage on the main side, and ensure the safe and reliable operation of the transformer.

[0084] The priority of each control logic is as follows Figure 2 As shown, from high to low, they are: manual control logic 1, protection cut-off control logic 2, abnormal control logic 3, forced control logic 4, periodic rotation control logic 5, and automatic control logic 6.

[0085] The monitoring system A1 and the monitoring system B2 of the present invention are connected simultaneously through the first communication channel and the second communication channel, which is called a "dual-path RS485 communication channel"; this "dual redundancy" mode provides double protection for the control of the converter transformer cooler, which can effectively improve the safety of transformer operation, and at the same time, by simplifying the system structure of the traditional transformer cooler monitoring device, the product production and maintenance costs are reduced.

[0086] The above description is only an embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. Transformer cooler redundant control system based on dual RS485, characterized in that: include: Touch screen A (3), touch screen B (4), monitoring system A (1) and monitoring system B (2); Among them, touch screen A (3) is connected to monitoring system A (1), and touch screen B (4) is connected to monitoring system B (2); The monitoring system A (1) is respectively connected to the control center A, the control center B and the transformer cooler as the control background of the substation, and the monitoring system B (2) is respectively connected to the control center A, the control center B and the transformer cooler.

2. The transformer cooler redundant control system based on dual-channel RS485 according to claim 1 is characterized in that: The monitoring system A (1) and the monitoring system B (2) have the same structure, and both include: a main processor unit (6), an RS485 communication module (7) connected to the main processor unit (6), an analog quantity acquisition module (8), a switch quantity input module (9), and an export control module (10); The main processor unit (6) is used to obtain the signals of the analog quantity acquisition module and the switch quantity input module and perform data analysis to calculate the current transformer oil level temperature, winding temperature and load percentage, analyze the control decision instructions obtained in real time to the output control module (10) according to the preset value of the cooler start / stop threshold and the control logic; An RS485 communication module (7) is used for serial communication with an RS485 communication module in a corresponding monitoring system; the touch screen A (3) is connected to the monitoring system A (1) via the RS485 communication module of the monitoring system A (1), and the touch screen B (4) is connected to the monitoring system B (2) via the RS485 communication module of the monitoring system B (2), for displaying system information; An analog quantity acquisition module (8) is used to acquire an analog quantity signal of basic data of the transformer detected by a sensor arranged on the transformer; A switch input module (9) is used to collect status signals of the transformer cooler from the transformer front-end control cabinet, control center A and control center B; The outlet control module (10) is used to receive the control decision instruction sent by the main processor unit (6), and control the transformer cooler according to the control decision instruction. The outlet control module is activated to control the start and stop of the cooler.

3. The transformer cooler redundant control system based on dual-channel RS485 according to claim 2 is characterized in that: The analog signals of the transformer basic data include: oil surface temperature signal, winding temperature signal, and grid-side bushing current signal; The status signals include: transformer fan start and stop, oil flow switch, protection cut signal, switch gear signal, manual automatic control signal, forced reset signal and protection cut reset signal.

4. The transformer cooler redundant control system based on dual-channel RS485 according to claim 1 is characterized in that: The monitoring system A (1) and the monitoring system B (2) communicate with the control center A or the control center B respectively using the IEC61850 communication protocol.

5. The control method of the transformer cooler redundant control system based on dual-channel RS485 according to claims 1 to 4, characterized in that: The following steps are involved: 1) According to the master-slave arbitration mechanism, monitoring system A (1) and monitoring system B (2) perform master-slave switching; 2) collecting oil level temperature signals, winding temperature signals and grid-side bushing current signals in real time through the analog quantity acquisition module (8), and sending analog signals of transformer basic data to the main processor unit (6); 3) The switch input module (9) collects status signals of the transformer cooler from the transformer front-end control cabinet, control center A and control center B; 4) The main processor unit (6) obtains the signals of the analog quantity acquisition module (8) and the switch quantity input module (9) and performs data analysis, calculates the current transformer oil level temperature, winding temperature and load percentage, and analyzes the transformer cooler according to the control logic priority to obtain a control decision instruction, and sends the obtained control decision instruction to the output control module (10) in real time; 5) The outlet control module (10) receives the control decision instruction sent by the main processor unit (6), and controls the transformer cooler according to the control decision instruction. The outlet control module is activated to control the start and stop of the cooler.

6. The control method of the transformer cooler redundant control system based on dual-channel RS485 according to claim 5 is characterized in that: In step 1), according to the master-slave arbitration mechanism, the monitoring system A (1) and the monitoring system B (2) perform master-slave switching, specifically: The monitoring system A (1) and the monitoring system B (2) use the following arbitration mechanism to perform active / standby switching: 1-1) Device startup phase: When the working status is normal, the monitoring system A (1) is the master side by default; 1-2) System operation stage: If the monitoring system B(2) on the standby side still determines that more groups of coolers need to be started after waiting for the coolers on the primary side to adjust the set time, the primary side and the standby side are switched; 1-3) System abnormality stage: If the monitoring system A(1) on the active side is in an abnormal working state and the monitoring system B(2) on the standby side is in normal working state, the active-standby switchover will be performed, and the original default monitoring system A(1) will become the standby side, and the original standby side monitoring system B(2) will become the active side; 1-4) The monitoring system A (1) and the monitoring system B (2) are connected simultaneously via a first communication channel and a second communication channel; When both the first communication channel and the second communication channel are disconnected, and the monitoring system A (1) and the monitoring system B (2) are both working normally, both monitoring systems switch to the master side and take the union to jointly control the transformer cooler.

7. The control method of the transformer cooler redundant control system based on dual-channel RS485 according to claim 5 is characterized in that: In step 4), the transformer cooler is analyzed according to the control logic priority to obtain control decision instructions, including: manual control logic, protection cut control logic, abnormal control logic, forced control logic, periodic rotation control logic, and automatic control logic from high to low priority; The manual control logic is used for the transformer cooler monitoring device to exit control after receiving a manual signal; The protection cut control logic is used to cut off all coolers when the transformer protection trips. The protection cut command needs to be reset locally in the transformer cooler monitoring device cabinet. The primary and standby monitoring systems exchange protection cut events and times through serial communication to achieve synchronization of the protection cut command and reset signal. The abnormal control logic is used to delay the start of all coolers between groups when analog quantity collection abnormalities or power failure occur in both monitoring systems; The forced control logic is used to receive the forced command from the control center to realize forced start or forced stop control of the cooler by group. The forced command needs to be reset locally in the transformer cooler monitoring device cabinet; the main side and standby side monitoring systems exchange forced events and times through serial communication to realize the action synchronization of forced commands and reset signals; The periodic rotation control logic is used to periodically rotate and start a group of coolers with the shortest running time and stop a group of coolers with the longest running time, and the primary side and standby side monitoring systems synchronize the actions of cooler control through serial communication; The automatic control logic is used to configure the oil temperature, winding temperature and transformer load to realize automatic start and stop control of the cooler according to the set value; when the main side monitoring system performs the start and stop control of the cooler, the relevant information is transmitted through serial communication, and the standby side synchronizes with the main side monitoring system to output the control signal of the corresponding cooler to realize the synchronous connection of the standby side control of the cooler when the main side is powered off.

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