On-line monitoring system for capacitive equipment dielectric loss angle

Abstract

The invention relates to a monitoring system for power transmission and transforming equipment, in particular to a capacitive equipment dielectric loss angle online monitoring system. The system is characterized by at least comprising a microprocessor, a leakage current signal acquisition module, a GPS synchronization module, a wireless communication module, an A / D sampling unit, and a frequency measurement sampling unit; in structure, a centralized management mode is used, a wireless data transmission technology and an Internet network technology are applied, and a layered distributed structure is achieved; according to the functional requirements, the invention divides the system into a monitoring layer, a control layer and an information layer. The manufacturer and operating management department (client) can visit the system in different places by only installing browser software and thus easily achieve remote maintenance and monitoring.

Description

technical field [0001] The invention relates to a monitoring system for power transmission and transformation equipment, in particular to an on-line monitoring system for the dielectric loss angle of capacitive equipment. Background technique [0002] Capacitive equipment is an important power transmission and transformation equipment, mainly including current transformers (TA), bushings, coupling capacitors, capacitive voltage transformers (CVT), etc., accounting for about 40% to 50% of the total substation equipment. It occupies an important position in the substation. Its insulation failure not only affects the safe operation of the entire substation, but also endangers the safety of other equipment and personal safety. At present, the maintenance work of power transmission and transformation equipment in my country is mainly to conduct regular preventive tests in accordance with the requirements of the "Electrical Equipment Preventive Test Regulations", that is, regular...

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Problems solved by technology

[0003] 1) A large number of cables need to be laid on site, and the construction volume is large, which makes maintenance and expansion inconvenient;

[0004] 2) Using the wired transmission mode, the signal transmission distance is too long, the analog signal will be attenuated to a certain extent and various electromagnetic interferences in the field cannot be avoided. In addition, the wired transmission mode also brings difficulties to the collection and transmission of remote signals. overcoming the bottleneck;

[0005] 3) When measuring the phase difference of power frequency signals, it is necessary to collect power frequency signals detected between different devices in different places (different places) synchronously. Therefore, accurate synchronization signals are required for acquisition devices in different places. The traditional method is to build a wired The communication network, for example, adopts the 485 bus, and the host computer issues data acquisition instructions, and then each monitoring extension unit starts data acquisition synchronously after receiving the acquisition instructions. This method has poor synchronization, and the small phase difference itself will be submerged in the synchronization error.

For monitoring capacitive equipment, the current sensor plays a key role. There is a certain phase difference between the source signal and the output signal of the sensor, and its performance directly affects the measurement accuracy and reliability of the dielectric loss of the capacitive equipment. Sampling is safe, the core structure is generally used, and the leakage current of electrical equipment such as CT, CVT, OY, TB, etc. is very small (all in mA level), so the traditional passive sensor cannot guarantee the accuracy and stability of the phase conversion error , and is prone to failure, so it is difficult to meet the requirements of insulation on-line measurement of dielectric loss

In addition, the anti-electromagnetic interference and environmental impact capabilities of traditional monitoring devices are poor, and the data processing function of the host computer software is not complete;

[0007] 5) The stability and repeatability of the dielectric loss measurement results are poor, and the reason is unknown, which affects the accuracy of the analysis;

[0008] 6) Lack of effective diagnostic theories and methods, only provide data, rich in information, but poor in knowledge, unable to establish correlations between various monitoring information, unable to distinguish between normal fluctuations in measurement results and fluctuations in fault conditions, it is very difficult Difficult to make accurate online diagnosis of insulation status

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