This standard specifies the limits, measurements, and qualification rate statistics of voltage deviation in power grid supply. This standard applies to the deviation of the supply voltage from the nominal voltage of the AC 50 Hz power system under normal operating conditions. 2 Normative References: The clauses in the following documents become clauses of this standard through reference in this standard. For dated reference documents, all subsequent amendments (excluding corrected content) or revisions are not applicable to this standard. Therefore, parties to agreements based on this standard are encouraged to study whether the latest versions of these documents can be used. For undated references, the latest version applies to this standard. GB/T156-2007 Standard Voltage (IEC 60038: 2002, MOD) 3 Terms and Definitions The following terms and definitions apply to this standard. 3.1 The nominal system voltage is used to indicate or identify the given value of the system voltage. [GB/T 156-2007, Definition 3.1] 3.2 Supply Terminals The connection point between the distribution system of the power supply department and the electrical system of the user. [GB/T 156-2007, Definition 3.3] 3.3 Supply voltage The line voltage or phase voltage at the supply point. [GB/T 156-2007, Definition 3.4] 3.4 Voltage deviation The relative deviation of the actual operating voltage from the system nominal voltage, expressed as a percentage. 3.5 Voltage qualification rate The percentage of the cumulative operating time of the actual operating voltage deviation within the limit range and the corresponding total operating statistical time
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