直流偏磁条件下高精度微型电流互感器的传变特性
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摘要
高精度微型电流互感器(CT)是高端智能电力仪表常用的前端取样器件,其传变特性受直流偏磁的影响。以0.02级微型电流互感器为例,通过实验数据来定量分析直流偏磁对CT传变特性的影响。研究表明,CT传变特性受直流偏磁的影响,这种影响随直流偏磁电流的增大而增大;角差随直流偏磁电流的增大而向正方向变化,随直流偏磁电流的增大而呈非线性快速增长;当直流偏磁电流超过微型电流互感器一次侧交流电流有效值的2%时,比差超出0.02级CT比差误差限值。直流偏磁将导致仪表测量偏小。
High precision miniature current transformer(CT) is a common front-end sampling device for high-end intelligent power meters. Its transfer characteristics are affected by DC bias. Taking 0.02 class miniature current transformer as an example, the influence of DC bias on the transmission characteristics of CT is quantitatively analyzed by experimental data. The results show that the transmission characteristics of CT are affected by DC bias, which increases with the increase of DC bias current. The angular difference changes with the increase of DC bias current in the positive direction, and increases nonlinearly with the increase of DC bias current. When DC bias current exceeds 2% of the effective value of AC current on the primary side of micro current transformer, the ratio difference exceeds 0.02 CT error. DC bias canl lead to smaller instrument measurement.
High precision miniature current transformer(CT) is a common front-end sampling device for high-end intelligent power meters. Its transfer characteristics are affected by DC bias. Taking 0.02 class miniature current transformer as an example, the influence of DC bias on the transmission characteristics of CT is quantitatively analyzed by experimental data. The results show that the transmission characteristics of CT are affected by DC bias, which increases with the increase of DC bias current. The angular difference changes with the increase of DC bias current in the positive direction, and increases nonlinearly with the increase of DC bias current. When DC bias current exceeds 2% of the effective value of AC current on the primary side of micro current transformer, the ratio difference exceeds 0.02 CT error. DC bias canl lead to smaller instrument measurement.
引文
[1] 李春来,汤晓宇,罗坤明.计量用电流互感器在3种铁心条件下传变特性的试验与分析[J].仪表技术与传感器 2015(4):104-106.
[2] 李春来,汤晓宇,黄业安.高精度微磁通电流互感器的研究[J].电测与仪表,2010(11):51-54.
[3] 李春来,汤晓宇,黄业安,等.计量用TA在直流偏磁条件下传变特性的实验与分析[J].电力自动化设备,2011(7):143-145.
[4] 李长云,李庆民,李贞,等.直流偏磁条件下电流互感器的传变特性[J].中国电机工程学报,2010(19):127-132.
[5] 国家质量监督检验检疫总局.电流互感器标准:GB 1208—2006[S].北京:中国标准出版社,2017.
[2] 李春来,汤晓宇,黄业安.高精度微磁通电流互感器的研究[J].电测与仪表,2010(11):51-54.
[3] 李春来,汤晓宇,黄业安,等.计量用TA在直流偏磁条件下传变特性的实验与分析[J].电力自动化设备,2011(7):143-145.
[4] 李长云,李庆民,李贞,等.直流偏磁条件下电流互感器的传变特性[J].中国电机工程学报,2010(19):127-132.
[5] 国家质量监督检验检疫总局.电流互感器标准:GB 1208—2006[S].北京:中国标准出版社,2017.