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

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Inductance

1. Main issues related to grounding across the entire station 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 in some areas.
(2) The grounding lines for continuous structures were not installed according to design specifications, resulting in more grounding points than required, which reduced the effectiveness of the designed grounding system.
(3) There are gaps in the grounding between structure brackets and equipment bodies, and the grounding points are not clearly marked or properly connected.
(4) Grounding in CT and CVT secondary circuits is not standardized, with multiple grounding points causing potential safety hazards.
(5) Both ends of the cable shield should be reliably grounded, but this is often overlooked.
(6) The grounding wire for outdoor lighting throughout the station is missing from the documentation.
(7) To meet countermeasure requirements, grounding copper bars must be installed in terminal boxes related to protection, with a minimum cross-sectional area of 16mm². These bars should be insulated and mounted using supporting insulators.
(8) Equipment grounding wires do not meet specifications, and solder joints lack anti-corrosion treatment. 2. Major issues in cable laying and secondary wiring include:
(1) Some cables are crossed or not neatly arranged.
(2) Cable nameplates have errors, such as incorrect text descriptions, temporary handwriting, mismatched with actual connections, missing labels, and unsecured lashings.
(3) Fireproof blocking is not done as per design, leading to poor sealing and failure due to construction practices. Some areas lack proper fireproof partitions and anti-vermin barriers.
(4) Parasitic loops exist in secondary circuits.
(5) Insulation at CT current terminal blocks is compromised.
(6) SF6 circuit breaker mechanism box motors are not isolated from flood power supplies.
(7) CT secondary circuits are open, and PT secondary circuits are shorted.
(8) Some outdoor terminal boxes are not waterproof. 3. Key problems with equipment and other aspects include:
(1) Design specifications do not clarify that large equipment like main transformers and shunt reactors should be fixed by welding.
(2) The angle of equipment clamps does not match the actual equipment received.
(3) Outdoor low-voltage hard busbars are not wrapped with insulation sleeves.
(4) Three-phase trip relays in circuit breaker control boxes are inconsistent and not adjusted on time.
(5) Excessive washers are used during equipment installation adjustments.
(6) Bolts are loose or missing, and some secondary junction boxes lack flat washers or are not securely fastened, leading to water ingress.
(7) Galvanization on frames and equipment brackets is uneven, with noticeable color differences. 4. Missing professional interfaces occur due to the involvement of multiple disciplines in substation projects. If coordination is inadequate, it can lead to design and construction blind spots. Common issues found during project acceptance include:
(1) Outdoor special electric panels and maintenance boxes' locations, installation methods, and dimensions were not clearly indicated when handing over electrical layouts to civil engineering professionals.
(2) The electrical secondary profession did not list the manufacturer's cable inventory, so buried pipes for secondary cables were not included during installation.
(3) During the signing of civil construction plans, the position of insulator-resistant string hanging points on civil frame beams was not checked against electrical requirements.
(4) The telephone line of the fault recorder modem was not connected.
(5) GPS signals were missed or not properly configured.
(6) Protection and communication interfaces are unclear, such as the absence of optical distribution frame terminal wiring diagrams.