两种三相电路总视在功率计算公式的关系  

Correlation between Two Formulas to Compute Total Apparent Power of Three-Phase Circuit

作　　者：李自成[1] 谭延良[1] 周新云[1] 赵不贿[1] 

机构地区：[1]江苏大学电气信息工程学院,江苏镇江212013

出　　处：《电气电子教学学报》2011年第5期32-34,共3页Journal of Electrical and Electronic Education

摘　　要：计算三相电路总视在功率的公式有两种:S1=SA+SB+SC和S2=(P2+Q2)^(1/2)。本文从一道三相电路总视在功率计算的选择题入手,探讨了S1和S2的关系。理论分析、计算示例和功率图都证实:当负载为对称负载时,S1=S2;当负载为阻抗角相等的非对称负载时,S1=S2;当负载为阻抗角不等的非对称负载时,S1>S2。There are two formulas S1 = SA ＋ SB ＋ Sc and S2=√（P^2＋Q^2） to compute total apparent power of three- phase circuit. Regarding the answer of a choice problem for the total apparent power of the three-phase circuit as a start, the correlation between S1 and S2 has been discussed. Theoretical analyses, computational examples and power figures validate： S1 = S2 with symmetrical loads, S1 = S2 with asymmetrical loads that have equal impedance angles and S1 〉 S2 with asymmetrical loads that have unequal impedance angles.

关 键 词：有功功率 无功功率 视在功率 三相电路 

分 类 号：TM131.4[电气工程—电工理论与新技术]