Online monitoring method for small control rectifier transformer

Abstract

The invention relates to the technical field of transformer detection, and provides a small control rectifier transformer on-line monitoring method, which comprises the following steps: step 1, collecting an on-off state signal of a high-breaking small circuit breaker in real time, and carrying out hardware filtering and software anti-shake processing; step 2, synchronously acquiring an alternating current input voltage signal and a direct current output voltage signal of the small control rectifier transformer; 3, transmitting the acquired signal to a local monitoring device through a control cable with the cross section area of 1.5 mm < 2 >; 4, AC / DC conversion and low-pass filtering are carried out on the voltage signals in the local monitoring device, and interference signals with the frequency higher than 50 Hz are filtered out. The rectifier bridge fault is accurately positioned by associating the opening and closing time sequence of the circuit breaker with the voltage fluctuation characteristics, and the misjudgment rate is reduced from 15% to lt; 1.2%, the duration time lt cannot be captured by manual inspection; for 5-second transient faults, the system can early warn breakdown of the rectifier tube 2 hours in advance, and hidden dangers can be found 14 days in advance compared with a traditional method.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer detection, in particular to an online monitoring method for a small-scale controlled rectifier transformer. Background Art

[0002] As the core power supply equipment for the GIS switchgear in 500kV booster stations, small controlled rectifier transformers are responsible for converting 220V AC to 220V DC. Their operational reliability directly impacts the operational safety of the isolation / earthing switches. Current mainstream monitoring solutions employ a discrete architecture: circuit breaker status monitoring utilizes mechanical relay contacts, voltage monitoring relies on a pointer voltmeter connected in parallel to the circuit, and data recording relies entirely on manual transcription of inspection reports.

[0003] Judging from the operation of small-scale controlled rectifier transformers in recent years, there have been cases where transformer failures have caused the isolation and grounding switch control circuits to fail to operate normally. Since small-scale controlled rectifier transformers are installed in the control cabinet, we usually mainly record the operating parameters of small-scale rectifier transformers through regular inspections, and cannot monitor their operating conditions in real time. To this end, we proposed an online monitoring device for small-scale controlled rectifier transformers, which collects data on the opening and closing status of high-break small circuit breakers, AC voltage signals, and DC voltage signals in real time. Through measuring devices, collection devices, optoelectronic conversion systems, and data switches, the data is transmitted in real time to the online monitoring background host, and is monitored in real time by operating personnel. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an online monitoring method for small-scale controlled rectifier transformers. This method addresses the problems of traditional operation and maintenance models, which rely on regular manual inspections, typically with inspection intervals of 24 hours or longer, and are unable to perceive transient state changes of the equipment in real time, resulting in significant deficiencies in monitoring timeliness. Furthermore, the method can only upload a single parameter (such as voltage), failing to meet multi-dimensional monitoring needs.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for online monitoring of a small controlled rectifier transformer, characterized in that it includes the following steps:

[0006] Step 1: Real-time acquisition of the opening and closing status signals of high-breakage miniature circuit breakers, and processing through hardware filtering and software anti-shake processing;

[0007] Step 2: synchronously collecting the AC input voltage signal and the DC output voltage signal of the small control rectifier transformer;

[0008] Step 3: Pass the above collected signal through 1.5mm 2 Cross-sectional area of ​​control cable to local monitoring device;

[0009] Step 4: Perform AC / DC conversion and low-pass filtering on the voltage signal in the local monitoring device to filter out interference signals with frequencies higher than 50 Hz;

[0010] Step 5: Calculate the effective value of voltage in real time through the DSP chip. The formula is:

[0011]

[0012] Where N is the number of sampling points, v k is the instantaneous voltage value;

[0013] Step 6: Convert the processed data into optical signals and transmit them to the backend host via optical fiber;

[0014] Step 7: The backend host displays the circuit breaker status and AC voltage V in real time AC , DC voltage V DC And abnormal alarm information.

[0015] Preferably, the step 1 uses 24 optoelectronic isolation switch input channels, and each channel is configured with an independent hardware filtering circuit.

[0016] Preferably, in the step 2, the AC voltage signal is collected using a voltage converter with a transformation ratio of 220V / 5V, and the DC voltage signal is collected using a Hall sensor with an accuracy of ±0.5%.

[0017] Preferably, the low-pass filter cutoff frequency in step 4 is set to 50 Hz, and the attenuation slope is -40 dB / dec.

[0018] Preferably, the photoelectric conversion module in step six adopts an SFP optical module, and the optical fiber transmission rate is ≥100 Mbps.

[0019] Preferably, the alarm triggering conditions in step seven include:

[0020] |V AC -220V|>15% for 10 seconds;

[0021] |V DC -220V|>10%, for 5 seconds;

[0022] The circuit breaker status is abnormal for 30 seconds.

[0023] Preferably, a temperature monitoring unit is added in step 2 and step 7 to collect the transformer winding temperature T in real time, and an alarm is triggered when T>85°C.

[0024] Preferably, the data storage in steps 6 and 7 adopts a circular storage mechanism, the local storage time is ≥30 days, and the sampling interval is ≤1 second.

[0025] Preferably, the steps 3 and 4 adopt a dual CPU redundant architecture, and when the main CPU fails, the backup CPU switches within 20ms.

[0026] Preferably, the step seven establishes a temperature-voltage correlation model, when and Start pre-fault diagnosis.

[0027] The present invention provides an online monitoring method for a small controlled rectifier transformer. It has the following beneficial effects:

[0028] 1. This invention significantly improves fault early warning capabilities through multi-parameter collaborative monitoring and intelligent analysis. By correlating circuit breaker opening and closing sequences with voltage fluctuation characteristics, rectifier bridge faults can be accurately located. Furthermore, fiber optic transmission improves by six orders of magnitude in strong electromagnetic environments. Hardware filtering and software anti-shake ensure that the anti-shake time of switch data acquisition exceeds 10ms, effectively suppressing interference.

[0029] 2. In terms of operation and maintenance efficiency and cost control, the present invention achieves a comprehensive upgrade in the fault diagnosis dimension, and can accurately identify the abnormal state where the capacitance value drops to 65% of the nominal value. At the same time, through the circular storage mechanism and dual CPU redundant architecture, data continuity and system reliability are guaranteed.

[0030] 3. The safe operation of the small-scale controlled rectifier transformer of the present invention is the basis for ensuring the safe operation of the isolation and grounding switch motors and their control system equipment, and the safe operation of the small-scale controlled rectifier transformer depends on the normal operation of its supporting equipment. Since the high-breakage miniature circuit breaker, AC voltage signal acquisition device, DC voltage signal acquisition device, photoelectric converter, and data switch operate with power for a long time, once a link fails during operation, the operating signals and parameters of the small-scale controlled rectifier transformer will lose monitoring, which seriously threatens the safe operation of the controlled rectifier transformer.

[0031] 4. The present invention adds a small-scale online monitoring device for the control rectifier transformer to perform online monitoring of its supporting equipment and the control rectifier transformer, which is beneficial for the operating personnel to timely grasp and understand the real-time operation status of the control rectifier transformer, and provide reliable technical guarantee for timely capturing equipment abnormal conditions, eliminating potential operation risks, reducing equipment accidents, and reducing accident repairs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Flowchart of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] An embodiment of the present invention provides an online monitoring method for a small controlled rectifier transformer, comprising the following steps:

[0035] Step 1: Real-time acquisition of the opening and closing status signals of high-break miniature circuit breakers, through hardware filtering and software anti-shake processing, and the use of 24-channel optoelectronic isolation switch input channels, each channel is equipped with an independent hardware filtering circuit;

[0036] Step 2: synchronously collect the AC input voltage signal and DC output voltage signal of the small control rectifier transformer. The AC voltage signal is collected using a voltage converter with a ratio of 220V / 5V, and the DC voltage signal is collected using a Hall sensor with an accuracy of ±0.5%;

[0037] Step 3: Pass the above collected signal through 1.5mm 2 Cross-sectional area of ​​control cable to local monitoring device;

[0038] Step 4: Perform AC / DC conversion and low-pass filtering on the voltage signal in the local monitoring device to filter out interference signals with frequencies higher than 50 Hz. The low-pass filter cutoff frequency is set to 50 Hz and the attenuation slope is -40 dB / dec.

[0039] Step 5: Calculate the effective value of voltage in real time through the DSP chip. The formula is:

[0040]

[0041] Where N is the number of sampling points, v k is the instantaneous voltage value;

[0042] Step 6: Convert the processed data into optical signals and transmit them to the backend host via optical fiber. The photoelectric conversion module uses an SFP optical module, and the optical fiber transmission rate is ≥100Mbps.

[0043] Step 7: The backend host displays the circuit breaker status and AC voltage V in real time AC , DC voltage V DC And abnormal alarm information, the alarm trigger conditions include:

[0044] |V AC -220V|>15% for 10 seconds;

[0045] |VDC -220V|>10%, for 5 seconds;

[0046] The circuit breaker status is abnormal for 30 seconds;

[0047] Establish a temperature-voltage correlation model, when and The system starts pre-fault diagnosis when the DC side filter capacitor capacitance drops to 65% of the nominal value (error ±0.5%), which can provide early warning 14 days earlier than the traditional insulation resistance detection method. By correlating the circuit breaker opening and closing sequence with the voltage fluctuation characteristics (such as V DC ) recovery delay>0.5s), accurately locate rectifier bridge faults, and reduce the misjudgment rate from 15% to <1.2% (measured data).

[0048] In addition, a temperature monitoring unit is added in steps 2 and 7 to collect the transformer winding temperature T in real time. When T>85℃, an alarm is triggered. Through the temperature-voltage correlation model, early hidden faults (such as capacitor degradation and winding overheating) are actively identified, and the equipment availability rate is increased from 98.2% to 99.8%. The data storage in steps 6 and 7 adopts a circular storage mechanism, with a local storage time of ≥30 days and a sampling interval of ≤1 second. It supports historical data backtracking and trend analysis, providing data support for equipment life prediction. Steps 3 and 4 use a dual-CPU redundant architecture. When the main CPU fails, the backup CPU switches within 20ms. When the AC input harmonic distortion rate suddenly increases by 3% and is accompanied by frequent circuit breaker operation, the system can warn of rectifier tube breakdown 2 hours in advance, discovering hidden dangers 14 days earlier than traditional methods.

[0049] The following is an introduction based on specific embodiments

[0050] Step 1: Circuit Breaker Status Signal Acquisition and Processing The open and close status signals of high-break miniature circuit breakers are collected in real time using 24 optoelectronically isolated digital input channels (Model: ADAM-4052), each equipped with an independent hardware filter circuit (RC filter: R = 4.7kΩ, C = 0.22μF). Vibration interference is eliminated through hardware filtering (cutoff frequency 1.5kHz) and software anti-shake processing (20ms sliding average + 15ms status delay confirmation).

[0051] Step 2: Synchronously collect the AC input and DC output voltage signals of the small controlled rectifier transformer. For AC voltage, use a 220V / 5V voltage converter (model: CT-CPT-220V / 5V) with an accuracy of ±0.1%. For DC voltage, use a Hall effect sensor (model: LEM LV25-P) with an accuracy of ±0.5% and a measurement range of 0-300VDC. Add a temperature monitoring unit: embed a three-wire PT100 temperature sensor (accuracy of ±0.5°C) at the winding end to collect real-time transformer winding temperature T at a sampling frequency of 10Hz.

[0052] Step 3: Signal transmission to the local monitoring device. The collected circuit breaker status signal, voltage signal and temperature signal are passed through a 1.5mm cross-sectional area. 2 KVVP22-2×1.5mm 2 The armored shielded cable is used to transmit data to the local monitoring device, with a transmission distance of 50 meters and the shielding layer grounded at both ends.

[0053] Step 4: Voltage signal processing and filtering: AC / DC conversion (full-bridge rectification + π-type filtering) and low-pass filtering are performed on the voltage signal in the local monitoring device: the low-pass filter cutoff frequency is set to 50 Hz, and a fourth-order Butterworth circuit is used with an attenuation slope of -40 dB / dec to filter out interference signals with frequencies higher than 50 Hz.

[0054] Step 5: Real-time calculation of voltage effective value The voltage effective value is calculated in real time by the DSP chip. The formula is:

[0055] Where N is the number of sampling points, 1kHz sampling rate, 20 points per cycle, v k is the instantaneous voltage value, and the recursive algorithm is used to optimize the calculation accuracy.

[0056] Step 6: Data photoelectric conversion and optical fiber transmission: The processed data is converted into optical signals through SFP optical modules and transmitted to the background host through single-mode optical fibers. The transmission rate is ≥100Mbps and the bit error rate is <10. -9 .

[0057] Step 7: Background data display and alarm The background host displays the circuit breaker status and AC voltage V in real time AC , DC voltage V DC and winding temperature T, and triggers an alarm according to the following conditions: Abnormal voltage alarm:

[0058] |V AC -220V|>15% for 10 seconds;

[0059] |V DC -220V|>10%, for 5 seconds;

[0060] Circuit breaker status alarm: The circuit breaker status is abnormal for 30 seconds;

[0061] Temperature alarm: winding temperature T>85℃;

[0062] Establishing temperature-voltage correlation model: When satisfying and When a fault occurs, early fault diagnosis is initiated to identify potential problems.

[0063] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for online monitoring of a small controlled rectifier transformer, characterized in that: The following steps are involved: Step 1: Real-time acquisition of the opening and closing status signals of high-breakage miniature circuit breakers, and processing through hardware filtering and software anti-shake processing; Step 2: synchronously collecting the AC input voltage signal and the DC output voltage signal of the small control rectifier transformer; Step 3: Pass the above collected signal through 1.5mm 2 Cross-sectional area of ​​control cable to local monitoring device; Step 4: Perform AC / DC conversion and low-pass filtering on the voltage signal in the local monitoring device to filter out interference signals with frequencies higher than 50 Hz; Step 5: Calculate the effective value of voltage in real time through the DSP chip. The formula is: Where N is the number of sampling points, v k is the instantaneous voltage value; Step 6: Convert the processed data into optical signals and transmit them to the backend host via optical fiber; Step 7: The backend host displays the circuit breaker status and AC voltage V in real time AC , DC voltage V DC And abnormal alarm information.

2. A method for online monitoring of a small controlled rectifier transformer according to claim 1, characterized in that: The step 1 uses 24 optoelectronic isolation switch input channels, and each channel is configured with an independent hardware filter circuit.

3. The online monitoring method for a small controlled rectifier transformer according to claim 1, characterized in that: In the step 2, the AC voltage signal is collected using a voltage converter with a transformation ratio of 220V / 5V, and the DC voltage signal is collected using a Hall sensor with an accuracy of ±0.5%.

4. The online monitoring method for a small controlled rectifier transformer according to claim 1, characterized in that: The low-pass filter cutoff frequency in step 4 is set to 50 Hz, and the attenuation slope is -40 dB / dec.

5. The online monitoring method for a small controlled rectifier transformer according to claim 1, characterized in that: The photoelectric conversion module in step six adopts an SFP optical module, and the optical fiber transmission rate is ≥100Mbps.

6. The online monitoring method for a small controlled rectifier transformer according to claim 1, characterized in that: The alarm triggering conditions in step seven include: |V AC -220V|>15% for 10 seconds; |V DC -220V|>10%, for 5 seconds; The circuit breaker status is abnormal for 30 seconds.

7. The online monitoring method for a small controlled rectifier transformer according to claim 1, characterized in that: In the steps 2 and 7, a temperature monitoring unit is added to collect the transformer winding temperature T in real time, and an alarm is triggered when T>85°C.

8. The online monitoring method for a small controlled rectifier transformer according to claim 1, characterized in that: The data storage in steps 6 and 7 adopts a circular storage mechanism, with a local storage duration of ≥30 days and a sampling interval of ≤1 second.

9. The online monitoring method for a small controlled rectifier transformer according to claim 1, characterized in that: The steps 3 and 4 adopt a dual CPU redundant architecture, and when the main CPU fails, the backup CPU switches within 20ms.

10. The online monitoring method for a small controlled rectifier transformer according to claim 1, characterized in that: The step 7 establishes a temperature-voltage correlation model. When the and Start pre-fault diagnosis.

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