Development of Electronic Voltage Transformer for Electric Rolling Stocks

서지정보

· 발행기관 : 한국철도학회
· 수록지 정보 : 한국철도학회논문집 / 26권 / 6호 / 445 ~ 453페이지
· 저자명 : 김남훈, 김동언, 김성욱, 김장호, 길경석

초록

Oil immersed or dry type potential transformers (PTs) for monitoring overhead line voltage are installed in rolling stock. It is difficult to ensure sufficient insulation in these PTs due to their direct connection to primary high-voltage conductors as well as their large volume and heavy weight of 70 to 250 kg. This paper proposes a non-contact and highprecision electronic voltage transformer (EVT) based on a derivative electric field (E) sensor for the miniaturization and digitalization of conventional core-type PTs. The prototype EVT is composed of an E sensor built into an epoxy-insulated bushing outside the high voltage conductor, with a rated voltage of 25 kV and an active integrator to restore the output voltage of the sensor to the original data. The ratio of voltage division is set to 6250 (25kV/4V). The voltage division ratio error and phase deviation were evaluated according to IEC 60044-7 and the maximum voltage division ratio error and phase deviation were found to be less than -0.032 % and 7 μs, respectively, as specified in Class 0.2, at 80 %, 100 %, and 120 % of the rated voltage. In addition, it was possible to measure within 0.2% of error even in the third, third, fifth, and seventh harmonics. The EVT is expected to be widely used because it can sufficiently meet the high precision, safety, miniaturization, and lightweight requirements of the current smart grid and substation digitization.

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