PT勵(lì)磁及傳變特性在信號(hào)注入法測(cè)量電容電流中的應(yīng)用
張利花,伍弘
(國(guó)網(wǎng)寧夏電力有限公司電力科學(xué)研究院,寧夏 銀川 750011)
摘 要:傳遞到電壓互感器(PT)一次側(cè)的實(shí)際電流值與額定值存在一定的誤差,導(dǎo)致計(jì)算出的電容電流誤差較大。以實(shí)驗(yàn)室電磁式電壓互感器為研究對(duì)象,通過(guò)對(duì)PT勵(lì)磁特性的試驗(yàn)研究及試驗(yàn)數(shù)據(jù)的分析,證明在注入不同頻率的信號(hào)時(shí),PT勵(lì)磁特性曲線的飽和特性并不相同,也說(shuō)明注入不合適頻段的信號(hào)時(shí),PT勵(lì)磁特性會(huì)影響信號(hào)注入法測(cè)量電容電流的準(zhǔn)確度。進(jìn)一步對(duì)PT傳變特性進(jìn)行試驗(yàn)研究及試驗(yàn)數(shù)據(jù)分析,設(shè)定了注入信號(hào)的合適頻率范圍,從而改進(jìn)了信號(hào)注入法測(cè)量電容電流的測(cè)量環(huán)節(jié)。
關(guān)鍵詞:信號(hào)注入法;電容電流;PT勵(lì)磁特性;PT傳變特性;頻率范圍
中圖分類號(hào):TM451 文獻(xiàn)標(biāo)識(shí)碼:A 文章編號(hào):1007-3175(2018)01-0046-05
Application of Excitation and Transmission Characteristic of Potential Transformer in Measurement of
Capacitive Current by Signal Injection Method
ZHANG Li-hua, WU Hong
(Power Research Institute of State Grid Ningxia Electric Power Company, Yinchuan 750011 , China)
Abstract: The actual current values delivered to the primary side of the potential transformer (PT) have some errors with the rated values, to result in greater errors in the calculated capacitive current. Taking the electromagnetic voltage transformer in laboratory for example, this paper analyzed the experimental study and test data of PT excitation characteristic to certify that the saturation characteristics of the excitation characteristic curves of the PT were different when signals with different frequencies injected. That’s why the excitation characteristic of PT had great influence on the accuracy in measurement of the capacitive current by signal injection method when the signal was injected into the inappropriate frequency band. Furthermore, the transmission characteristic test of PT was carried out and the test data were analyzed to determine the frequency range of the injected signal, so as to improve the measurement link of the signal injection method of measuring the capacitive current.
Key words: signal injection method; capacitive current; excitation characteristic of potential transformer; transmission characteristic of potential transformer; frequency range
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