Analysis of main problems in electrical installation of substation - News - Global IC Trade Starts Here Free Products

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Inductance

1. The main issues with grounding across all stations include:
(1) When connecting electrical cables to the grounding wire in the cable trench, the number of completed trenches was not verified, leading to insufficient grounding within the trench.
(2) The grounding lines for the continuous row structure of the construction unit did not meet design requirements, resulting in more actual grounding points than designed, causing a lack of sufficient grounding lines for the frame.
(3) There is a gap between the grounding of the structure bracket and the equipment body, and no clear marking for the grounding point.
(4) Grounding in the CT and CVT secondary circuits is not standardized, with multiple grounding points present.
(5) Both ends of the cable shield are properly grounded.
(6) The grounding wire for outdoor lighting across the station is missing.
(7) In addition to the power box and power supply box at the station, grounding copper bars must be installed in other terminal boxes related to protection, with a minimum cross-sectional area of 16mm². These copper bars should be insulated and mounted using supporting insulators.
(8) The grounding wires for equipment do not meet specifications, and solder joints are not treated with anti-corrosion measures. 2. Key problems with cable installation and secondary wiring include:
(1) Some cables are crossed and not neatly arranged.
(2) Issues with cable nameplates: incorrect text descriptions, temporary handwriting, mismatch with actual connections, missing tags, unsecured lashing, and uneven alignment.
(3) Fireproof blocking of cables is not done according to design, leading to loose sealing and failure due to poor construction. The thickness of fireproof partitions does not meet design standards. Common issues include failure to block against small animals and not restoring screen cabinets after opening during construction.
(4) Parasitic loops exist in the secondary circuit.
(5) Insulation at the CT current terminal block is zero.
(6) The motor in the SF6 circuit breaker mechanism box is not separated from the flooding power supply.
(7) CT secondary circuit open, PT secondary circuit shorted.
(8) Some outdoor terminal boxes are not waterproof. 3. Main issues with equipment and other aspects include:
(1) Design specifications do not mention that large equipment like main transformers and shunt reactors should be fixed by welding.
(2) The angle of the equipment clamp differs from the actual equipment received.
(3) Outdoor low-voltage hard busbars are not wrapped with an insulating sheath.
(4) The three-phase trip relay in the circuit breaker control box is inconsistent and not adjusted timely.
(5) Excessive gaskets are used during equipment installation adjustments.
(6) Bolts are not tightened or missing. Some secondary junction boxes lack flat washers or have loosely fixed bolts, leading to water ingress and moisture.
(7) Frame and equipment brackets are not evenly galvanized, resulting in significant color differences. 4. Omissions in professional interfaces occur due to the involvement of many disciplines in substation projects. If cooperation is not tight enough, there may be blind spots in design and construction. Common issues found during project acceptance include:
(1) The location, installation method, and size of outdoor special electric panels and maintenance boxes were not clearly indicated when providing electrical layout plans to civil engineering professionals.
(2) The secondary cable inventory provided by the manufacturer was not listed by the electrical secondary profession, so buried pipes for secondary cables were not included during installation.
(3) When signing off on the civil construction plan, the position of the insulator-resistant string hanging point on the civil frame beam was not checked to ensure it met electrical requirements.
(4) The telephone line of the fault recorder modem was not connected.
(5) GPS signal was missed.
(6) The interface between protection and communication is unclear, such as missing wiring diagrams for the optical distribution frame terminal.