This standard specifies permissible variation limit, measurement and statistic method of qualification rate of power system with nominal frequency 50Hz.
This standard is not applicable to the frequency deviation limit of electrical equipment.
2 Terms and Definitions
For the purpose of this standard, the following terms and definitions apply.
2.1
Nominal frequency
It refers to the frequency selected by system design.
2.2
Frequency deviation
It refers to the difference of actual value and nominal value of system frequency.
2.3
Impact load
It refers to the load periodically or aperiodically adopting rapid change power from power grid during production (or operation) process.
2.4
Frequency qualification rate
It refers to the percentage ratio of accumulated operation time and corresponding total operating statistic time for actual operating frequency deviation within limit range.
3 Frequency Deviation Limit
3.1 The permissible value of frequency deviation limit for power system under normal operation condition shall be ±0.2Hz. When the system capacity is smaller, the deviation limit may be broadened to ±0.5Hz.
3.2 The frequency deviation limit caused by impact load is detailed in Appendix A of this standard.
3.3 The statistic method of frequency qualification rate in power system is detailed in Appendix B of this standard.
