【摘要】 三相电路中总有功功率的测量是学术和工程的重要内容,其中三瓦计法、二瓦计法、一瓦计法的具体接法、物理本质、适用范围、相互关系是值得探讨的话题.本文基于总有功功率的定义逐一探析三瓦计法的4种接线方式、二瓦计法的3种接法.结果分析表明:三瓦计法适用于任意三相制电路,共N接法的单表读数物理意义清晰,共A、共B、共C 3种接法中读数的物理意义模糊、总有功功率应为三表读数的代数和;二瓦计法适用于任意三相三线制电路,共A、共B、共C 3种接法中单表读数无明确物理意义,总有功功率亦为两表读数之代数和;一瓦计法适用于任意三相对称负载;共A、共B、共C 3种接法是等价的,是电流相量封闭性、相名相对且有序性的必然结果.更多还原

【Abstract】 The measurement of the total active power in three-phase circuits is important in both the academic and engineering.It is worthy to discuss the specific connection ways,the physical essence,the scope of application and the interrelation with the three-wattmeter methods,the two-wattmeter methods and the one-wattmeter methods.Four types of connection with three-wattmeter methods and three types of connection with two-wattmeter methods were studied based on the definition of the total active power.The conclusions are following.With the common-N connection method,the physical meaning of the reading on a single meter is clear.But it is unclear with the methods of common-A,common-B,common-C connection,and the total active power should be the algebraic sum of these three.Two-wattmeter methods can be a match for any three-phase three-wire circuit.Among any one of common-A,commonB and common-C method,single meter reading has no clear physical meaning,and the total active power should be algebraic sum of two numerical readings.One-wattmeter methods can be a match for any three-phase symmetrical circuit.The connection types of common-A,common-B,common-C are equivalent,due to closure property of current phase,the relativity and orderliness of phase sequence.更多还原