GB/T 12325-2008 in English

《GB/T 12325-2008电能质量 供电电压偏差》由TC1（全国电压电流等级和频率标准化技术委员会）归口，主管部门为国家标准化管理委员会。
本标准代替GB/T 12325-2003《电能质量　供电电压允许偏差》。
本标准规定了电网供电电压偏差的限值、测量和合格率统计。
本标准适用于交流50Hz电力系统在正常运行条件下供电电压对系统标称电压的偏差。
本标准与GB/T 12325-2003相比主要变化如下：
―――标准名称改为《电能质量　供电电压偏差》；
―――为便于理解和实施，前三个术语与GB 156协调一致（见3.1~3.3），修改了“电压偏差”的定义
（见3.4），增加了“电压合格率”术语（见3.5）；
―――增加20kV电压等级的电压偏差限值（见4.2）；
―――正文增加“供电电压偏差的测量”，以增强标准的可操作性；
―――增加了“附录A　电压合格率统计”、“附录B　电网电压监测及地区电网电压合格率的统计”；

1 Scope

This standard specifies the limit, measurement and qualification rate statistics for supply voltage deviation of power grid.
This standard is applicable to the deviation of supply voltage to nominal system voltage for AC 50Hz power system under normal operation condition.

2 Normative References

The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent modification to, or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest edition of these documents is applicable. For undated references, the latest edition of the normative document is applicable to this standard.
GB/T 156-2007 "Standard Voltage" (IEC 60038:2002, MOD)

3 Terms and Definitions

For the purpose of this standard, the following terms and definitions apply.
3.1
Nominal system voltage
It refers to the given value used for marking or identifying system voltage.
[GB/T 156-2007, Definition 3.1]
3.2
Supply terminals
It refers to the coupling point of power distribution system of power supply department and electrical system of user.
[GB/T 156-2007, Definition 3.3]
3.3
Supply voltage
It refers to line voltage or phase voltage at supply terminals.
[GB/T 156-2007, Definition 3.4]
3.4
Voltage deviation
It refers to the relative value of deviation for actual operating voltage to system voltage, which is expressed with percentage.
3.5
Voltage qualification rate
It refers to the percentage ratio of accumulated operation time and corresponding total operation time for actual operation voltage deviation within limit range.

Contents
Foreword I
1 Scope
2 Normative References
3 Terms and Definitions
4 Limit of Supply Voltage Deviation
5 Measurement of Supply Voltage Deviation
Appendix A (Informative) Statistics of Voltage Qualification Rate
Appendix B (Informative) Monitoring of Power Grid Voltage and Statistics for Qualification Rate of Regional Power Grid Voltage