2　General Provisions

2.0.1　Power equipment and lines shall be provided with relay protections and automatic devices to respond to short-circuit faults and abnormal operations.These relay protections and automatic device shall be able to timely indicate faults and abnormal operations of equipment and lines，and clear faults and restore power supply as quickly as possible.

2.0.2　Electrical equipment and lines shall be provided with main protections，backup protections and abnormal operation protections，and，if necessary，the auxiliary protections.

2.0.3　Relay protections and automatic devices shall meet the requirements for reliability，selectivity，sensitivity and rapidity and shall observe the following regulations:

1　Relay protections and automatic devices shall have such functions as automatic on-line detection，blocking and device abnormity/fault alarm.

2　Where it is required that relay protections and automatic devices coordinate with adjacent equipment and lines，the sensitivity coefficient and operation time of adjacent levels shall coordinate with each other.

3　Where faults occur to protected equipment and lines within the reach of protection，necessary'sensitivity coefficient shall be provided.

4　Protections shall be capable of clearing short-circuit faults as quickly as possible.If it is required to accelerate the clearing of short-circuit faults，protections may be allowed to operate unselectively，but automatic reclosing devices or automatic switch-in devices for standby power sources and equipment shall be used to minimize the area exposed to outage.

2.0.4　The sensitivity coefficient of protections shall be calculated based on unfavorable normal operation modes and unfavorable fault types.When necessary，impacts of short-circuit current attenuation shall be taken into account.The minimum sensitivity coefficient of various relay protections shall be in accordance with Appendix B to this code.