1. The activation and deactivation of relay protection and automatic devices (hereinafter referred to as protection devices) and the switching of protection pressure plates must be executed according to the orders of the relevant dispatching authority. However, when an abnormality in the relay protection device endangers the safe operation of the system, it is permissible to deactivate the device first and then report it.
2. After the protection device is activated or deactivated, the relevant dispatching authority should be immediately informed, and the type of protection device, the reason for activation/deactivation, the time, etc., should be recorded in the operation log.
3. Before any electrical equipment is energized, the protection device must be put into operation according to the orders of the relevant dispatching authority. It is strictly forbidden to operate electrical equipment without protection.
4. To prevent protection devices connected to AC voltage from malfunctioning, the protection device must not lose AC voltage during operation and switching operations. If it is unavoidable, the trip pressure plate of the protection device may be withdrawn after approval from the relevant dispatching authority.
5. In a multi-source substation, when power is received from only one source line, all protection devices of that line's circuit breaker must be deactivated (except for special requirements of longitudinal protection).
6. Precautions for substation duty personnel during switching operations
6.1. High-voltage electrical equipment is not allowed to be charged without instantaneous protection. The charging protection of bus tie and sectional circuit breakers is only activated when charging the busbar and deactivated after charging is completed; Anti-interference dielectric loss tester is widely used in the power industry for measuring the dielectric loss of transformers, instrument transformers, bushings, capacitors, arresters, and other equipment., and the charging protection of bypass circuit breakers is only activated when charging the busbar and deactivated after charging is completed;
6.2. When charging lines and standby equipment, the reclosing and standby power supply automatic switching devices should be temporarily deactivated;
6.3. When performing bus transfer operations on double busbars, for comparison-type bus differential protection, the non-selective mode should be activated first (for ratio-braking bus differential protection, the interconnection pressure plate should be activated first), and then the control fuse of the bus tie switch should be removed;
6.4. When each busbar of a double-busbar system has its own voltage transformer, under normal conditions, the AC voltage for the protection devices of elements connected to the busbar should be taken from the voltage transformer of the busbar to which they are connected;
6.5. For the bus tie circuit breaker in double-busbar operation, no protection is allowed to be activated except for bus differential, breaker failure, and main transformer backup protection (unless special regulations apply);
6.6. The standby power supply automatic switching device must be put into operation after the associated main equipment is put into operation and deactivated before the associated main equipment is taken out of operation;
6.7. When bypassing, the protection settings of the bypass circuit breaker must match the settings of the line being bypassed.
7. Before working on protection devices and secondary circuits, operating personnel must strictly review the work tickets of relay protection staff. Changes to setting values and wiring alterations must have approved setting value notification sheets before work is allowed. For any work that may cause protection device malfunction, effective preventive measures should be taken.
When relay protection work is completed, operating personnel should carefully inspect and accept the work, such as checking whether the disconnected wiring, components, signs, etc., have been restored to normal, and whether the positions of pressure plates and the contents recorded in the equipment work log are clear. After any work on the AC circuits of protection devices, relay protection personnel should check the correctness of the circuits and verify the phase, phase sequence, and amplitude.
8. The setting values for newly commissioned and in-service protection devices should be issued by the setting calculation department. After changing the setting values, operating personnel should first verify the correctness of the setting value sheet number with the dispatching authority before putting the device into operation. One copy of the protection device setting value notification sheet should be kept at the substation.
9. Before newly installed protection devices or those with changed circuits are put into operation, their drawings and documentation should be correct and complete and signed by the person who made the changes.
10. When directional protection and differential protection are newly put into operation, or after changes to primary equipment or modifications to AC secondary circuits, the vectors should be checked using load current and working voltage. Differential protection that has not undergone vector checking should be activated when charging transformers or lines, and before officially carrying load, the trip pressure plate should be withdrawn for vector checking. Only after the vectors are confirmed correct can the protection be officially put into operation.
