GB/T 15945-2008Power quality - Frequency deviation for power systems (English PDF)

Foreword

This standard replaces GB/T 15945-1995 "Power quality power system frequency tolerance." This standard and GB/T 14945-1995 compared to the main changes are as follows.

--- Standard name changed to "power quality power system frequency deviation";

--- Increasing the term "nominal frequency of 2.1";

--- The original standard "4 measuring instrument" to expand and refine the content, the words "4 frequency deviation measurement";

--- Delete the original standard "frequency variation 2.2";

--- Original standard frequency deviation caused by the impact load limit on moves to Appendix A;

--- Added Appendix B "frequency pass rate statistics." This standard Annex A, Annex B normative appendix.

1 Scope

This standard specifies a nominal frequency of 50Hz power system frequency deviation limits, measurements and statistical methods of passing rate.

This standard does not apply to the frequency deviation limits for electrical equipment.

2 Terms and definitions

The following terms and definitions apply to this standard.

3 Frequency deviation limit

3.1 Power frequency deviation limit under normal operating conditions, the system is ± 0.2Hz. When the system capacity is small, the deviation limit can be relaxed to ± 0.5Hz.

Frequency deviation caused by the impact load limit of 3.2 of this standard, see Appendix A.

3.3 statistical methods in power system frequency pass rate of this standard, see Appendix B.

4 Measuring frequency deviation

Measurement frequency deviation of 4.1 Measuring grid fundamental frequency, each taking 1s, 3s or 10s in the interval meter to integer integer cycle accumulation period of time than (and 1s, 3s or 10s overlapping single clock cycle should be discarded). Measurement interval do not overlap each 1s, 3s or 10s interval should be in 1s, 3s or 10s at the start of the count clock. This standard does not exclude a more advanced method of measuring the frequency of use.