1. Conditions that must be met for construction
(1) Joint review of drawings and preparation of detailed work instructions based on information and approval from the manufacturer.
(2) The quality of construction projects related to the installation of box-type transformers complies with the current national standards for construction and acceptance of construction projects.
(3) The positions of the embedded parts and cable embedded pipes meet the design requirements and the embedded parts are firm.
2. Construction Preparation
2.1 Transformer Foundation Inspection
(1) Work with the owner and supervisor to inspect the construction quality of the transformer foundation and complete the inspection sheet registration, signed and confirmed by all parties, and any issues discovered will be reported and addressed in a timely manner.
(2) Check carefullythe dimensions of the horizontal and vertical axes of the transformer foundation and the position of the embedded pipe, and check them with the dimensions shown in the drawings. Only when they are correct can you proceed with the work. next step.
2.2 Unpacking and inspection of the transformer
(1) When unpacking and inspecting the transformer upon arrival, it shall be inspected with the relevant personnel of the owner, supervisor and the manufacturer.
(2) Measure and record the impact value of the impact recorder before unloading the truck. This value must be less than 3G.
(3) Check that there is no damage to the appearance of the transformer and the paint surface is intact, and record it.
(4) Check that the components inside the transformer are not moved or contaminated.
3. Install the transformer in place
(1) Install the steel foundation of the canal of the transformer on the embedded parts. Pay attention to the leveling and alignment of the steel channel foundation and embedded parts. are firmly welded. Remove the coating from the parts to be welded then apply anti-corrosion paint.
(2) After the fan is lifted, the lifting transformer is directly located on the foundation, and the jack is used for leveling and alignment.
(3) Connect the transformer to the foundation according to the fixing method (screwing or welding) specified by the manufacturer.
(4) If the product arrives separately, install the outer box after the transformer is installed and aligned.
(5) Hang the panels and clean the inside of the transformer housing.
(6) Finished product protection work must be carried out before the next process.
4. Cable lines between the box transformer and the fan
Cable lines between the EOThe link and the box transformer are laid in underground cable trenches, and between each fan and the box. transformer Install an insulated and armored cross-linked polyethylene power cable of type YJY23-(3×240), 0.6/1kV and a YJY23-(4×240), 0.6/1kV cable. Cable head grounding: 1500m of 40mm2 copper glue wire (including cable intermediate joint). The bill of quantities is as follows:
(1) YJY23-3×240 26/35kV 240mm2 16km cable;
(2) YJY23-3×95 26/35kV 95mm2 14km cable ;
(3) YJY23-3×50 26/35kV 50mm2 cables 5km;
(4) 3 sets of 35kV cable terminals (YJY23-3×240 26/35kV) ;
(5) 58 sets of 35kV cable terminals (YJY23- 3× 50 26/35kV);
(6) 35kV cable intermediate joint (quantity determined according to the cable feed length);
(7) YJY23-(3×240), 0.6/1kV 2100m;
(8) YJY23-(4×240) ), 0.6/1kV 2100m; 232 sets of 1kV cable noses. There are 58 box-type transformers; 47cable junction boxes (including 8 terminals with 4 cables; 39 terminals with 3 cables).
5. Line Retest Process
Due to project needs, a combination of total station and GPS positioning system is used for retesting. Observation and recording of the instruments must be carried out by two people respectively and must be checked on the same day of operation.
The new line test must be performed in one direction. If carried out from both ends towards the middle, the junction must exceed at least two C piles (a base tower). Check whether the center stake of the tower is stable and whether it is loose. If there is any looseness, first secure it firmly and then measure. For tower piles that are retested and calibrated, clear and stable panels must be put in place. For the construction boundary between the two construction units, they must be retested up to the corner and beyond the two fondations only after contacting the two foundations. The other party must confirm that the pits can be separated. When retesting the build, complete the records in a timely manner, and the records must be true and accurate. If you encounter any discrepancies with the design during retesting, report them immediately and do not handle them yourself.
6. Crossing power lines
Before crossing the construction, the technical manager must check the angle of intersection of the crossing point and the uninterrupted power line to be crossed depending on the crossing. cross-section diagram of crossing point in line construction drawing. The height of the overhead ground wire to the ground at the intersection point, the height of the bottom conductor to the ground at the intersection point, the width between the edges of the conductor and the ground conditions are tested again. On the babased on the results of the new tests, a covering construction plan is selected.
(1) When crossing uninterrupted power lines, before the construction of the wire assembly, the construction unit must request in writing from the operating unit the "output reclosure" of the live line, and the construction of uninterrupted crossing can only be carried out after implementation. When a fault is triggered during construction, it is strictly prohibited to transmit force energy without obtaining approval from the on-site command.
(2) When erecting the span, the safety factor of lifting tools and ground anchors near the anchor should be increased from 20% to 40%.
(3) Grounding protection measures shall be taken for the idler pulleys on the pole towers on both adjacent sides of the lifting mechanism. Before crossing the construction, all safety devicesGrounding must be installed and reliably connected to the tower.
(4) Construction of wiring on uninterrupted power lines must be carried out in good weather. Operations must be stopped in the event of lightning, rain, snow, frost, fog, relative humidity above 85% or strong winds above. level 5. If the above situation occurs during construction, the deployed nets and ropes must be safely protected.
(5) The cable must be dried before use and its unit resistance must be measured with a 5,000 V megger.
(6) If the passage of all cables from cable car and fixed cables of insulating poles is not completed on the same day, the crossing cables and lead cables should be collected and properly preserved, and should not be left behind. open at night.
(7) During the process of laying lead cables and insulating cables qui are not completely separated from live lines, operators such as pulling cables and tying them should wear insulating boots and insulating gloves during operation.