Due to the complex internal structure of the box transformer and the large number of power distribution devices, special care must be taken in the normal operation and maintenance.
（1） Basic requirements for box type substation operation
1. The floor for box type equipment shall be placed at a higher place rather than at a low-lying place to avoid rainwater pouring into the box and affecting the operation. When pouring concrete platform, there should be a space to facilitate the laying of incoming and outgoing cables.
2. There must be two reliable connections between the box and the grounding grid. The grounding and neutral connection of the box transformer can share one grounding grid. The grounding grid is generally grounded at the four corners of the foundation and then connected into one.
3. Dongfang Dahua Power reminded that there should be no illegal stacking around the box type equipment to ensure the ventilation and operation inspection needs of electrical equipment. The box transformer is mainly cooled by natural air circulation, and the door of the transformer room should not be blocked.
4. The loop network switch, transformer, arrester and other equipment in the high-voltage power distribution device shall be inspected and maintained regularly, and the defects found shall be repaired in a timely manner, and the preventive insulation test shall be carried out regularly. During operation, the mechanical interlock shall be removed correctly and the insulating rod shall be used for operation.
（2） Patrol maintenance of box type substation
The box transformer shall conduct regular inspection (at least once a month) according to the inspection and maintenance cycle, test the temperature at the connection of cable terminals, check the operation of equipment, and conduct tests if necessary.
The general inspection items are as follows:
1. Whether the foundation is firm, whether the holes are blocked, and whether there is moisture in the cabinet.
2. Whether the grounding device is complete and well connected, and whether the grounding resistance meets the requirements.
3. Whether there is any change in the outdoor environment and whether it affects the safety of traffic and pedestrians.
4. Check the load condition of each feeder, whether the three-phase load is balanced or overloaded, whether the switch opening/closing position and instrument indication are correct, and whether the control device works normally.
5. The dedusting inside the box transformer shall be conducted once a year. The surface of the cabinet body and the air box of the high voltage chamber and low voltage chamber can be wiped with a damp cloth. The transformer in the transformer room shall be dedusted with air blowing or vacuum cleaner.
6. The daily maintenance and overhaul of the fan check the operation of the fan. Dongfang Dahua Power reminded that if it is not running, use the temperature and humidity controller, adjust it to below the existing temperature, and start the fan for inspection.
7. Maintenance and overhaul of high-voltage switch and low-voltage switch electric operating mechanism
(1) Check whether the pointer of the barometer is in the green area. If it enters the red area, conduct opening and closing operation. Notify the manufacturer immediately for handling.
(2) For the lubrication of mechanical parts, the opening and closing operation test can be conducted after the general lithium base grease (grease) lubrication is completed.
(3) Routine test of cables and lightning arresters: According to the requirements of routine test, insulation test and leakage current test shall be carried out for cables and lightning arresters.
8. Auxiliary routine test Routine test of temperature and humidity controller; Routine test of smoke alarm device; Fastening and inspection of terminal strip: fastening and inspection of standard parts.
9. The terminal strip may become loose due to thermal expansion and cold contraction during maintenance. All terminals in the terminal room shall be retightened during annual patrol inspection. Note: Before retightening, please confirm that both the primary AC circuit and the secondary control circuit are powered off to avoid electric shock!
10. Precautions for box type transformer maintenance
(1) The door of the box transformer substation is equipped with a windproof mechanism, which is a mechanism to ensure that it is kept in the fully open state. When closing the box door, the root of the windproof mechanism must be lifted up, and then the door cannot be pulled hard to prevent the mechanism or door from deforming and affecting the normal use of the box transformer substation!
(2) After the local manual operation of the high-voltage load switch is completed, put the load switch operating handle back on the handle bracket inside the outer door to avoid loss.
(3) When the standby circuit of the high-voltage ring network cabinet is not connected to the cable temporarily, the standby circuit should be locked before the ring network cabinet is powered on, or the cable seat should be blocked with a matching insulating cap to avoid accidents!
(4) The dust cap provided by the box transformer manufacturer for the ring main unit cannot replace the insulating cap!
(5) It is not allowed to use any short circuit plug to insert into the test hole during operation, otherwise the voltage sensor will be damaged.
(6) The low-voltage disconnecting switch can only be operated when it is in the unlocked position. Do not force it!