Maintenance of Relay Protection Devices
1. Duty personnel should regularly inspect and check the relay protection devices, and keep operation records of the relays, terminal blocks, and various instruments in the protection panels, excitation panels, automatic panels, power panels, DC panels, high-voltage panels, local area panels, and control room panels of the hydropower station.
2. Establish a post responsibility system, ensuring that each panel is assigned to a duty personnel. Everyone has a post, and each post has a responsible person.
3. Perform cleaning work on the panels of the relay protection devices. Generally, the cleaning cycle is once per day shift. Cleaning must be carried out by two people, with one supervising to avoid electric shock and secondary circuit short circuits or grounding accidents. For relays with voltage higher than 250V, cleaning must be done under power outage conditions if possible. A feather duster is recommended as the cleaning tool.
4. Regularly inspect and evaluate the relay protection devices: ① Check whether the markings and names of components on the panels are complete. ② Check whether the transfer switches and various buttons are flexible in operation, and whether the contacts have pressure and burn marks. ③ Check whether the optical word signs and red/green indicator bulbs in the control room are intact. ④ Check whether the screws on meters, relays, and terminal blocks on each panel are loose. ⑤ Check whether the secondary lead terminals of voltage transformers and current transformers are intact. ⑥ Check whether the wiring is neat and the fixing clips are not detached. ⑦ Check whether the operating mechanism of the circuit breaker operates normally. Any abnormal phenomena in the above aspects must be handled promptly. Every year, the station leaders must lead technical personnel and maintenance personnel to conduct a secondary equipment evaluation of the relay protection devices. Based on the evaluation results, they are classified into three categories. Equipment that has been proven by operation to be in good technical condition without defects and can ensure safe and economical operation is classified as Class I equipment. Equipment that is basically intact, with general defects in individual parts but still safe to operate without endangering personal or equipment safety, is classified as Class II equipment. Equipment with major defects that endanger safe operation, reduce output, or have severe "three leaks" is classified as Class III. Defects in relay protection must be handled promptly, and it is strictly forbidden to operate with defects. For relay protection devices that have been repaired and handled, establish a defect ledger to facilitate future maintenance work.
