三相电路中功率现象的解释及无功功率的分类

ANALYSIS OF POWER PHENOMENON AND CLASSIFICATION OF REACTIVE POWER IN THREE-PHASE CIRCUIT

该文对三相电路的功率现象进行了详细的物理分析,并指出:三相瞬时有功功率之和不为常数是电源电压为非正弦及不对称所必须付出的代价;提出了在非正弦及不对称电路中,三相电路(包括三相三线制和三相四线制)中不仅存在相间无功流动,而且可能存在电源与负载间的无功流动的观点,并在通用瞬时功率理论的基础上,给出了基于最小能量传输损失的三相相间流动的无功功率、三相电源与三相负载间流动的无功功率定义。文中所定义的相间流动的无功电流、三相电源与三相负载间流动的无功电流以及有功电流之间具有两两正交的关系。如果忽略电源与负载间的无功流动,则通用瞬时功率理论与赤木泰文瞬时无功理论一致。

Detailed physical analysis of power phenomenon in three-phase circuit is given. It verifies that the total three phase instantaneous power cannot remain constant in circuits with distort and unbalanced source. This conclusion gives a further physical explanation of the active current defined by the universal instantaneous power theory (UIPT). This paper also points out: in nonsinusoidal and unbalanced circuit, there are not only reactive power flowing among phases, but also reactive power flowing between 3-phase source and 3-phase load. Proceeding from minimum transmission loss criterion, this paper presents the definition of reactive power flowing among phases and reactive power flowing between 3-phase source and 3-phase load. Active current, reactive current flowing among different phases and reactive current flowing between source and load have a pairwise orthogonal relationship in the framework of UIPT. If the reactive power flowing between source and load is ignored, the UIPT is identical with H.Akagi抯 reactive power theory.