A method and system for evaluating the error state of a capacitive voltage transformer

Abstract

The invention discloses a capacitive voltage transformer error state online monitoring method and a system thereof. The method comprises the steps of through synchronous triggering of a synchronous signal unit, acquiring and calibrating measurement data of an operation three-phase capacitive voltage transformer, establishing a threshold which represents a statistics characteristic parameter of thecapacitive voltage transformer error state and a statistics characteristic quantity of a standard normal operation state by means of a principal component analysis method; acquiring measurement dataof the three-phase capacitive voltage transformer in the operation state, according to a statistics characteristic parameter, representing a statistics characteristic quantity of the three-phase capacitive voltage transformer error state by means of an adaptive principal component analysis method, and comparing the statistics characteristic quantity with a statistics threshold for determining whether the error state of the capacitive voltage transformer is normal; and when the statistics characteristic quantity of the measured data exceeds the statistics threshold, performing diagnosis on theerror abnormity of the capacitive voltage transformer. The capacitive voltage transformer error state online monitoring method and the system thereof can realize real-time online evaluation on the error state of the capacitive voltage transformer.

Description

technical field [0001] The invention belongs to the field of electric power technology, and more specifically relates to a method and system for evaluating an error state of a capacitor voltage transformer (CapacitorVoltage Transformer, CVT). Background technique [0002] The measuring transformer is an important primary equipment in the substation and an important part of the electric energy metering device. Among them, capacitive voltage transformers are widely used in power systems with voltage levels of 110kV and above because of their good insulation performance and economy. Compared with the traditional electromagnetic voltage transformer, the structure of the capacitive voltage transformer is more complicated, the error stability in the operation process is not high, and it is easy to appear out of tolerance phenomenon, which affects the fairness and accuracy of electricity trading. In serious cases It may even threaten the safe operation of the power grid. As a mea...

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Problems solved by technology

[0005] In view of the defects of the prior art, the purpose of the present invention is to solve the problem that the traditional regular off-line maintenance method is no longer suitable for capacitive voltage transformers with poor measurement error stability, and the evaluation of transformers in operation requires the use of high-precision standards. However, due to the constraints of the operating environment, it is difficult to put the high-precision standard into the high-pressure environment. Even if it is put into the online, it can only be calibrated for a short time.

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