A computer monitoring-based voltage transformer insurance slow-fusion diagnosis control method

Abstract

The application provides a computer monitoring-based voltage transformer insurance slow-fusion diagnosis control method, a generator outlet PT primary insurance slow-fusion diagnosis strategy excitation regulator and a computer monitoring system establish communication, and the sampling values of the excitation two-channel machine end voltage are uploaded to the monitoring LCU, the computer monitoring system LCU comprehensively judges by sampling the excitation system machine end voltage, the state quantity of the excitation system, and combining other voltage transformers and the exchange sampling table signal, slow-fusion alarm of the excitation PT primary fuse is realized, the generator outlet voltage transformer primary insurance slow-fusion comprehensive diagnosis strategy designed based on the characteristics of the multi-system and multi-signal fusion of the computer monitoring system has the characteristics of high coverage and accurate diagnosis, and the machine end PT abnormal problem can be more accurately and efficiently judged, the primary insurance slow-fusion diagnosis strategy based on the computer monitoring system can conveniently establish an interactive interface with the LCU, the generator excitation, the AGC and the AVC device, automatic linkage control is realized, and the problems of false adjustment and false control are avoided.

Description

Technical Field

[0001] This invention relates to the field of computer monitoring systems, and more specifically, to a method for diagnostic control of slow-blow fuses in voltage transformers based on computer monitoring. Background Technology

[0002] Voltage transformers are installed at the generator terminals for generator protection, excitation, speed regulation, and measurement. The primary side of the voltage transformer is connected to the generator output bus via a high-voltage fuse. Due to issues such as fuse quality and operating environment, slow blowing of the primary fuse often occurs under normal operating voltage. This slow drop in secondary voltage may cause protection devices to fail to issue a "PT disconnection alarm" signal in time, making it difficult for operators to detect. Furthermore, due to imperfect PT slow-blow diagnostic logic in some excitation regulators, it can easily lead to abnormal increases in generator terminal voltage and malfunctions in generator protection. Therefore, we propose an improvement: a computer-monitored slow-blow diagnostic control method for voltage transformer fuses. Summary of the Invention

[0003] The purpose of this invention is to address the problems raised in the existing background technology, and to achieve the goal of transmitting the protection signals of the voltage transformer (PT) for "PT disconnection," analog signals of the voltage transmitter, communication signals of the cross-data acquisition meter, active and reactive power transmitters, excitation and speed regulation, etc., to the computer monitoring system, fully utilizing the comprehensive signal coverage advantage of the LCU of the computer monitoring system, and realizing the purpose of the voltage transformer primary fuse slow-blow diagnostic strategy based on the local control unit (LCU) of the computer monitoring system. This invention provides the following technical solution:

[0004] A computer-monitored method for the diagnostic control of slow-blow fuses in voltage transformers includes the following steps:

[0005] Step 1: Generator outlet PT primary fuse slow-blow diagnostic strategy. The excitation regulator establishes communication with the computer monitoring system and sends the sampled values ​​of the excitation two-channel generator terminal voltage to the monitoring LCU. The computer monitoring system LCU makes a comprehensive judgment by sampling the generator terminal voltage of the excitation system, various state quantities of the excitation system, and combining the signals of other voltage transformers and cross-data acquisition meters, and realizes the slow-blow alarm of the excitation PT primary fuse.

[0006] Step 2: When the voltage sampling value of the main channel terminal is greater than that of the backup channel terminal terminal and the difference is greater than 2%; when there are no alarms in the excitation system and the voltages of other voltage transmitters are normal, the monitoring system will determine that the primary fuse of excitation PT1 or PT2 is slowly blowing.

[0007] Step 3: The local control unit of the computer monitoring system makes a comprehensive judgment based on the combined judgment of the voltage and current signals from the data acquisition meter, single-phase voltage transmitter, relay protection system alarm, active and reactive power transmitter, excitation and speed controller, and three-phase voltage imbalance, single-phase voltage transformer measurement value > threshold, protection system signal, and active and reactive power transmitter measurement signal to distinguish between slow blowing of the PT primary fuse and secondary open circuit, and correctly determine the slow blowing of the PT primary fuse.

[0008] As a preferred technical solution of the present invention, it also includes step four: a linkage control strategy after the voltage transformer primary fuse slow-blow alarm, wherein the computer monitoring system LCU diagnoses the excitation PT primary fuse slow-blow alarm.

[0009] As a preferred technical solution of the present invention, in step four, before the excitation system voltage transformer sampling abnormal disconnection alarm, the LCU output signal is monitored to act on the excitation AVR channel switching or control mode switching to avoid abnormal rise of the generator terminal voltage.

[0010] As a preferred technical solution of the present invention, it also includes step five: the computer monitoring system LCU diagnoses other slow fuse alarms, monitors the LCU output signal to switch the active and reactive power transmitters, avoids misadjustment and miscontrol of active and reactive power; according to the specific application, it switches the speed governor control mode from "power closed loop" mode to "opening" mode to prevent abnormal active power control of the unit.

[0011] As a preferred technical solution of the present invention, step five involves implementing a plant-wide AGC and AVC closed-loop control function exit strategy based on the impact of the PT primary safety malfunction on the unit's active and reactive power transmitter measurements.

[0012] As a preferred technical solution of the present invention, in step one, the computer monitoring system LCU samples the excitation system terminal voltage, and the control mode after receiving the excitation system terminal voltage command is automatic operation mode, and the terminal voltage is greater than the rated terminal voltage of a preset ratio.

[0013] As a preferred technical solution of the present invention, in step one, if the computer monitoring system LCU excitation system status quantity receives a status quantity entry command from the monitoring system, then it enters the excitation system.

[0014] As a preferred technical solution of the present invention, in step three, the local control unit of the computer monitoring system converts the AC current signal in the measured circuit into an AC voltage signal through a voltage transmitter and the voltage transmitter conversion circuit outputs it to the monitoring circuit.

[0015] As a preferred technical solution of the present invention, in step three, the local control unit of the computer monitoring system is connected to the active and reactive power transmitters via a network cloud device through the PLC processor in the device.

[0016] As a preferred technical solution of the present invention, in step four, the voltage transformer of the excitation system is connected to the resistor voltage divider module and the step-down filter module.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] In the solution of this invention:

[0019] 1. The integrated diagnostic strategy for slow-blow primary fuse of generator outlet voltage transformer, designed based on the multi-system and multi-signal fusion characteristics of the computing monitoring system, has the characteristics of high coverage and accurate diagnosis, and can more accurately and efficiently determine abnormal problems of generator terminal PT.

[0020] 2. The slow-blow diagnostic strategy of the primary fuse based on the computer monitoring system can easily establish interactive interfaces with LCU, generator excitation, AGC, and AVC devices to realize automatic linkage control and avoid problems such as misadjustment and miscontrol. Attached Figure Description

[0021] Figure 1 A flowchart provided for this invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are specific implementations of the present invention and are not limited to all embodiments.

[0023] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely illustrates some embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0024] It should be noted that, in the absence of conflict, the embodiments and features and technical solutions in the embodiments of the present invention can be combined with each other. It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0025] Example 1: Please refer to Figure 1A computer-monitored method for slow-blowout diagnosis and control of voltage transformer fuses includes the following steps: Step 1: The generator outlet PT primary fuse slow-blowout diagnosis strategy establishes communication between the excitation regulator and the computer monitoring system, and sends the sampled values ​​of the excitation two-channel generator terminal voltage to the monitoring LCU. The computer monitoring system LCU makes a comprehensive judgment by sampling the generator terminal voltage of the excitation system, various state quantities of the excitation system, and combining the signals of other voltage transformers and cross-sample meters, and realizes the slow-blowout alarm of the primary fuse of the excitation PT.

[0026] Step 2: When the voltage sampling value of the main channel terminal is greater than that of the backup channel terminal terminal and the difference is greater than 2%; when there are no alarms in the excitation system and the voltages of other voltage transmitters are normal, the monitoring system will determine that the primary fuse of excitation PT1 or PT2 is slowly blowing.

[0027] Step 3: The local control unit of the computer monitoring system makes a comprehensive judgment based on the combined judgment of the voltage and current signals from the data acquisition meter, single-phase voltage transmitter, relay protection system alarm, active and reactive power transmitter, excitation and speed controller, and three-phase voltage imbalance, single-phase voltage transformer measurement value > threshold, protection system signal, and active and reactive power transmitter measurement signal to distinguish between slow blowing of the PT primary fuse and secondary open circuit, and correctly determine the slow blowing of the PT primary fuse.

[0028] Step 4: After the voltage transformer primary fuse slow-blow alarm, the linkage control strategy is implemented. The computer monitoring system LCU diagnoses the slow-blow alarm of the excitation PT primary fuse.

[0029] Step 4: Before the excitation system voltage transformer sampling abnormality disconnection alarm occurs, monitor the LCU output signal to switch the excitation AVR channel or control mode to avoid abnormal rise in the generator terminal voltage.

[0030] Step 5: The computer monitoring system LCU diagnoses other slow-blow alarms of primary fuses and monitors the LCU output signal to switch between active and reactive power transmitters to avoid misadjustment or miscontrol of active and reactive power; depending on the specific application, it switches the speed governor control mode from "power closed loop" mode to "opening" mode to prevent abnormal active power control of the unit.

[0031] Step 5: Based on the impact of the PT primary fuse abnormality on the unit's active and reactive power transmitter measurements, implement the plant-wide AGC and AVC closed-loop control function exit strategy.

[0032] Step 1: The computer monitoring system LCU samples the excitation system terminal voltage. After receiving the excitation system terminal voltage command, the control mode is automatic operation, and the terminal voltage is greater than the preset ratio of the rated terminal voltage.

[0033] Step 1: The computer monitoring system monitors the LCU excitation system status. If it receives a status command from the monitoring system to enter the excitation system, it will enter the excitation system.

[0034] Step 3: The local control unit of the computer monitoring system uses a voltage transmitter. The voltage transmitter conversion circuit converts the AC current signal in the measured circuit into an AC voltage signal and outputs it to the monitoring circuit.

[0035] Step 3: The local control unit of the computer monitoring system connects to the active and reactive power transmitters via the active and reactive power transmitters, which are electrically connected to the network cloud device via the PLC processor in the equipment.

[0036] Step 4: Connect the voltage transformer in the excitation system to the resistor divider module and the step-down filter module.

[0037] Working Principle: In the process of using this invention, Step 1: The excitation regulator establishes communication with the computer monitoring system to establish a slow-blow diagnostic strategy for the primary fuse of the generator outlet PT. It sends the sampled values ​​of the excitation terminal voltages of the two excitation channels to the monitoring LCU. The computer monitoring system LCU comprehensively judges the excitation system terminal voltage, various excitation system status variables, and signals from other voltage transformers and cross-sensor meters to realize a slow-blow alarm for the primary fuse of the excitation PT. Step 2: When the sampled value of the primary channel terminal voltage is greater than the sampled value of the backup channel terminal voltage and the difference is greater than 2%, and the excitation system has no alarm... In case of an alarm, if the voltages of other voltage transmitters are normal, the monitoring system identifies the slow-blowing primary fuse of excitation PT1 or PT2. Step three: The local control unit of the computer monitoring system comprehensively judges the situation by analyzing the cross-sampling meters, single-phase voltage transmitters, relay protection system alarms, active and reactive power transmitters, and active and reactive power voltage and current signals from the excitation and speed controller. It also comprehensively judges the situation by analyzing three-phase voltage imbalance, single-phase voltage transformer measurements exceeding the threshold, protection system signals, and active and reactive power transmitter measurement signals to distinguish between slow-blowing primary fuses and secondary circuit breaks in the PTs, correctly identifying the slow-blowing primary fuse. Step four also includes a linkage control strategy after the voltage transformer primary fuse slow-blowing alarm. The computer monitoring system LCU diagnoses the slow-blowing alarm of the excitation PT primary fuse. Step four: Before the excitation system voltage transformer sampling abnormality and circuit break alarm, the monitoring LCU output signal acts on the excitation AVR channel switching or control mode switching to prevent abnormal voltage rise at the generator terminals. This also includes step five: the computer monitoring system LCU diagnoses other slow-blow alarms of primary fuses, monitors the LCU output signal to switch the active and reactive power transmitters, avoiding misadjustment and miscontrol of active and reactive power; depending on the specific application, it switches the speed governor control mode from "power closed-loop" mode to "opening" mode to prevent abnormal active power control of the unit. Step five: based on the impact of abnormal PT primary fuse conditions on the unit's active and reactive power transmitter measurements, it acts on the plant-wide AGC and AVC closed-loop control function exit strategy. Step one: the computer monitoring system LCU samples the excitation system terminal voltage. After receiving the excitation system terminal voltage command, the control mode is automatic operation, and the terminal voltage is greater than the preset proportion of the rated terminal voltage. Step one: the computer monitoring system LCU receives the excitation system status quantity. If it receives the status quantity from the monitoring system to enter the excitation system command, it enters the excitation system. Step three: the local control unit of the computer monitoring system uses a voltage transmitter. The voltage transmitter conversion circuit converts the AC current signal in the measured circuit into an AC voltage signal and outputs it to the monitoring circuit. Step 3: The local control unit of the computer monitoring system connects to the active and reactive power transmitters via a network cloud device through the PLC processor in the equipment. Step 4: The voltage transformer in the excitation system is connected to the resistive voltage divider module and the step-down filter module for data transfer.

[0038] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described herein. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the specific embodiments described above. Therefore, any modifications or equivalent substitutions to the present invention, as well as all technical solutions and improvements that do not depart from the spirit and scope of the invention, are covered within the scope of the claims of the present invention.

Claims

1. A computer monitoring-based control method for diagnosing a slow-melting fuse of a voltage transformer, characterized by, The method comprises the following steps: Step one, the generator outlet PT primary fuse slow melting diagnosis strategy excitation regulator and computer monitoring system LCU establish communication, the excitation two channel machine end voltage sampling value is sent to the computer monitoring system LCU, the computer monitoring system LCU is judged by sampling excitation system machine end voltage, the state quantity of excitation system, combined with other voltage transformer, the signal of exchange table, realizes the slow melting alarm of excitation PT primary fuse; Step two, when the main channel machine end voltage sampling value > standby channel machine end voltage sampling value and the difference > 2%; the excitation system has no any alarm condition, and other voltage transducer voltage is normal, the monitoring discriminates that the excitation PT1 or PT2 primary fuse is slow melting; Step three, the local control unit of computer monitoring system LCU is judged by exchange table, single-phase voltage transducer, relay protection system alarm, active and reactive power transducer, excitation and speed regulator active and reactive voltage and current signal, is judged by three-phase voltage imbalance, single-phase voltage transformer measurement > threshold value, protection system signal, active and reactive power transducer measurement signal, distinguishes PT primary fuse slow melting and secondary wire breakage, and correctly discriminates PT primary fuse slow melting.

2. The computer monitoring based control method for diagnosing and controlling the slow melting of the voltage transformer fuse according to claim 1, characterized by, It also includes step four, voltage transformer primary fuse slow melting alarm linkage control strategy, the computer monitoring system LCU diagnoses the slow melting alarm of excitation PT primary fuse.

3. The computer monitoring based control method for diagnosing and controlling the slow melting of the voltage transformer fuse according to claim 2, characterized by, The step four, before the sampling abnormal wire break alarm of excitation system voltage transformer, the output signal of computer monitoring system LCU acts on excitation AVR channel switching or control mode switching.

4. The computer monitoring based control method for diagnosing and controlling the slow melting of the voltage transformer fuse according to claim 3, characterized by, It also includes step five, the computer monitoring system LCU diagnoses other primary fuse slow melting alarm, and the output signal of computer monitoring system LCU acts on active and reactive power transducer switching, to avoid active and reactive power misadjustment, miscontrol; according to specific use, it acts on speed regulator control mode switching, from power closed loop mode to opening degree mode.

5. The computer monitoring based control method for diagnosing and controlling the slow melting of the voltage transformer fuse according to claim 4, characterized by, Step five, according to the influence of PT primary fuse abnormal condition on unit active and reactive power transducer measurement value, the AGC, AVC closed loop control function of whole plant is exited.

6. The computer monitoring based control method for diagnosing and controlling the slow melting of the voltage transformer fuse according to claim 5, characterized by, The step one computer monitoring system LCU is sampled by the machine end voltage of excitation system, and the control mode after receiving the machine end voltage instruction of the excitation system is automatic operation mode, and the machine end voltage is greater than the rated machine end voltage of the preset proportion.

7. The computer monitoring based control method for diagnosing and controlling the slow melting of the voltage transformer fuse according to claim 6, characterized by, The step one computer monitoring system LCU excitation system state quantity, if the state quantity into the magnetic system instruction issued by the computer monitoring system LCU is received, then enter the excitation system.

8. The computer monitoring based control method for diagnosing and controlling the slow melting of the voltage transformer fuse according to claim 7, characterized by, The step three, the local control unit of computer monitoring system LCU is converted into an alternating voltage signal by the voltage transducer conversion circuit in the measured loop and output to the monitoring circuit.

9. The computer monitoring based control method for diagnosing and controlling the slow melting of the voltage transformer fuse according to claim 8, characterized by, The step three, the local control unit of computer monitoring system LCU is connected with the network cloud device by the active and reactive power transducer through the PLC processor in the device.

10. The computer monitoring based control method for diagnosing and controlling the slow melting of the voltage transformer fuse according to claim 9, characterized by, The step four, in the excitation system voltage transformer, the voltage transformer of the excitation system is connected with the resistance voltage dividing module and the step-down filter module.

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