CN-121983398-A - Insulator for direct-current converter transformer and online monitoring method thereof

CN121983398ACN 121983398 ACN121983398 ACN 121983398ACN-121983398-A

Abstract

The invention discloses an insulator for a direct current converter transformer and an on-line monitoring method thereof, and relates to the technical field of insulators. The insulator for the direct current converter transformer can synchronously acquire three key state data, namely the internal mechanical stress of an insulator, the connection state of a first metal accessory and a second metal accessory and the overall temperature distribution in real time through the design of the multi-stage state monitoring system which comprises the first-stage sensing unit, the second-stage sensing unit and the third-stage sensing unit, wherein the insulator body and the connection structure are integrated, so that real-time monitoring of the insulator and multi-dimensional comprehensive information acquisition are realized, early warning is realized based on the multi-dimensional comprehensive information, preliminary early warning can be realized according to single data, simultaneously, time alignment and comprehensive judgment can be carried out on the multi-dimensional data, high-level fault early warning can be carried out, the stability and reliability of the insulator are improved, and the occurrence of sudden faults is reduced.

Inventors

ZUO JIANGUO
LIU GUOHUA
Zuo Yidan
ZHOU SHANGUO

Assignees

萍乡市双华电瓷制造有限公司

Dates

Publication Date: 20260505
Application Date: 20260316

Claims (10)

1. The insulator for the direct current converter transformer comprises an insulating piece (1), a first metal accessory (2) arranged at the upper end of the insulating piece (1) and a second metal accessory (3) arranged at the lower end of the insulating piece (1), and is characterized by further comprising a multi-stage state monitoring system integrated in the insulator body and a connecting structure; The multi-stage condition monitoring system includes: A first-stage sensing unit (4) for monitoring the state of mechanical stress inside the insulating member (1); A second-stage sensing unit (5) for monitoring the state of mechanical connection between the first metal fitting (2) and/or the second metal fitting (3) and an external connection The third-stage sensing unit (6) is used for monitoring the whole and partial temperature distribution of the insulator; the monitoring signals of the first-stage sensing unit (4), the second-stage sensing unit (5) and the third-stage sensing unit (6) are configured to be transmitted to an external data processing unit (7) for analysis and judgment of the health state of the insulator.
2. Insulator for a direct current converter transformer according to claim 1, characterized in that the first stage sensing unit (4) comprises at least one sensing fiber (41) arranged axially along the insulator (1), the sensing fiber (41) being inscribed with a plurality of grating sensing structures (42) forming a fiber grating sensor string for measuring the strain of the insulator (1) at different positions axially.
3. The insulator for the direct current converter transformer according to claim 2, wherein the insulator (1) is a composite insulator with a solid structure, the central axis position of the insulator (1) comprises a core rod (11) and an axial through hole is preset in the core rod (11) to serve as a sensor channel (12), the sensing optical fiber (41) is penetrated and fixed in the sensor channel (12), and two ends of the sensor channel (12) are packaged through sealant (8).
4. Insulator for a direct current converter transformer according to claim 1, characterized in that the second stage sensing unit (5) comprises at least one piezoelectric vibration sensor (51), which piezoelectric vibration sensor (51) is mounted on a mounting flange face or a connecting bolt of the first metal accessory (2) and/or the second metal accessory (3) for monitoring vibration signals.
5. An insulator for a direct current converter transformer according to claim 3, characterized in that the third stage sensing unit (6) is a distributed temperature sensing system, the third stage sensing unit (6) sensing elements being multiplexed with the sensing optical fibers (41).
6. An insulator for a direct current converter transformer according to claim 3, characterized in that the third stage sensing unit (6) sensing element is a temperature measuring optical fiber independently arranged on the surface of the insulator (1), and the temperature measuring optical fiber is used for acquiring temperature distribution data of the surface of the insulator (1).
7. Insulator for a direct current converter transformer according to claim 1, characterized in that the data processing unit (7) comprises a signal demodulation module, a data storage module and an intelligent analysis module; the signal demodulation module is used for demodulating an original signal from the multi-stage state monitoring system; The data storage module is used for storing historical monitoring data and threshold parameters; The intelligent analysis module is configured to perform primary early warning based on threshold discrimination and advanced fault diagnosis based on multi-parameter spatio-temporal correlation analysis.
8. The insulator for a direct current converter transformer according to claim 7, wherein the logic of the intelligent analysis module performing advanced fault diagnosis comprises determining that there is a defect development inside the insulator (1) and generating a fault alarm when the first stage sensing unit (4) monitors a stepwise increase or continuous increase of the strain value at a specific location and at the same time the third stage sensing unit (6) monitors an abnormal increase of the temperature of the same corresponding area beyond a preset range.
9. The insulator for the direct current converter transformer according to claim 1, wherein the first metal accessory (2) and the second metal accessory (3) are cast steel flanges, mounting holes for bolts to pass through are formed in the cast steel flanges, the first metal accessory (2) is used for being connected with a bus fitting, and the second metal accessory (3) is used for being fixed on a valve side sleeve flange of the direct current converter transformer or an equipment bracket.
10. An on-line monitoring method for a dc converter transformer insulator according to any one of claims 1-9, characterized in that the on-line monitoring method comprises the steps of: Step S1, strain distribution data in the insulator (1) are collected in real time through the first-stage sensing unit (4), vibration data of a connecting point of the first metal accessory (2) and the second metal accessory (3) are collected in real time through the second-stage sensing unit (5), and axial temperature distribution data of the insulator are collected in real time through the third-stage sensing unit (6); step S2, synchronously transmitting the multi-source data acquired in the step S1 to a data processing unit (7); Step S3, in the data processing unit (7), respectively and independently comparing the strain distribution data, the vibration data and the temperature distribution data with a preset safe operation threshold value, and triggering primary early warning if any data exceeds the threshold value; S4, carrying out space-time correlation fusion analysis on the strain distribution data, the vibration data and the temperature distribution data; and step S5, based on the analysis result of the step S4, if the mechanical stress abnormality and the local overheat are identified to be synchronous in time and coincide in space, the structural fault is determined, and high-level fault early warning and positioning information is generated and reported.

Description

Insulator for direct-current converter transformer and online monitoring method thereof Technical Field The invention relates to the technical field of insulators, in particular to an insulator for a direct current converter transformer and an on-line monitoring method thereof. Background The DC converter transformer is core equipment in a high-voltage DC power transmission system, a valve side sleeve outgoing line of the DC converter transformer is usually connected and supported through a special insulator, the operation environment of the insulator is complex, the insulator bears the comprehensive effects of high voltage, high current, mechanical load and environmental stress for a long time, the performance reliability of the insulator is directly related to the safety and stability of the whole DC power transmission system, and at present, the state monitoring of the DC converter transformer insulator mainly depends on the traditional preventive test and regular inspection, such as the measurement of the surface leakage current, the infrared temperature measurement, the development of partial discharge detection and the regular appearance inspection and mechanical strength sampling inspection, and partial external defects or serious degradation problems can be found to a certain extent. However, the prior art means have the following defects that firstly, the traditional method is mostly developed offline or periodically, the real-time continuous sensing of the running state of equipment cannot be realized, the sudden defect is difficult to capture in time, and the prior online monitoring means often focus on single physical quantity, such as monitoring temperature or monitoring partial discharge only, and lack of synchronous comprehensive judgment on multi-dimensional information such as the mechanical stress state, the electrical connection state and the temperature distribution of an insulator, for example, micro cracks can be generated on an inner core rod of the insulator due to process defects or long-term stress fatigue, but the micro cracks are difficult to be discovered in early stage only by external temperature or electrical monitoring, and meanwhile, the loosening problem of a connecting bolt of a metal accessory is difficult to be discovered in time before overheat is initiated, so that the prior art is difficult to comprehensively, early stage, accurately and prophylactically evaluate the whole health state of the insulator, and influence the timeliness of a state overhaul strategy. Disclosure of Invention Aiming at the defects of the prior art, the invention provides the insulator for the direct current converter transformer and the on-line monitoring method thereof, and by integrating the design of a multi-stage state monitoring system comprising a first-stage sensing unit, a second-stage sensing unit and a third-stage sensing unit in an insulator body and a connecting structure, the invention can synchronously and real-timely acquire three key state data of internal mechanical stress of an insulator, connection state of a first metal accessory and a second metal accessory and integral temperature distribution, realizes real-time monitoring of the insulator and multi-dimensional comprehensive information acquisition, and early warning based on the multi-dimensional comprehensive information. The insulator for the direct current converter transformer comprises an insulating part, a first metal accessory arranged at the upper end of the insulating part, a second metal accessory arranged at the lower end of the insulating part, and a multi-stage state monitoring system integrated in the insulator body and a connecting structure; The multi-stage condition monitoring system includes: The first-stage sensing unit is used for monitoring the internal mechanical stress state of the insulating part; A second level sensing unit for monitoring the mechanical connection state between the first metal accessory and/or the second metal accessory and the external connecting piece The third-stage sensing unit is used for monitoring the whole and partial temperature distribution of the insulator; The monitoring signals of the first-stage sensing unit, the second-stage sensing unit and the third-stage sensing unit are configured to be transmitted to an external data processing unit for analysis and judgment of the health state of the insulator. Preferably, the first-stage sensing unit comprises at least one sensing optical fiber axially distributed along the insulating element, and a plurality of grating sensing structures are inscribed on the sensing optical fiber to form a fiber grating sensor string for measuring strains of the insulating element at different positions along the axial direction. Preferably, the insulator is a composite insulator with a solid structure, the central axis of the insulator comprises a core rod, an axial through hole is preset in the core rod to serve as a sensor channel, th