IEC 60255的本部分适用于电力系统中的同步相量测量系统。它定义了同步相量、频率和频率测量的变化率。它描述了测量这三个量的时间标签和同步要求。它规定了在静态和动态条件下评估这些测量值的方法和符合本标准的要求。它定义了相量测量单元（PMU），可以是独立的物理单元，也可以是另一个物理单元内的功能单元。 本文件未规定计算相量、频率或频率变化率的硬件、软件或方法。

This part of IEC 60255 is for synchronized phasor measurement systems in power systems. It defines a synchronized phasor (synchrophasor), frequency, and rate of change of frequency measurements. It describes time tag and synchronization requirements for measurement of all three of these quantities. It specifies methods for evaluating these measurements and requirements for compliance with the standard under both static and dynamic conditions. It defines a phasor measurement unit (PMU), which can be a stand-alone physical unit or a functional unit within another physical unit. This document does not specify hardware, software or a method for computing phasors, frequency, or rate of change of frequency.