Power transformer core quality inspection standard

2019 - power transformer core quality inspection standard 03 - 30 15:05:32 1, core should level off, insulating film without loss, laminated closely, side of the silicon steel sheet should not be tilted or wavy, the various parts of the core surface should be no oil and impurities, between plates should be no short circuit, overlapping phenomenon, joint clearance requirements 2, pieces of iron core and upper and lower clamp, square iron, pressure plate, bottom baseboard shall maintain good insulation between; 3, steel plate between the core and must have the obvious uneven clearance; Insulation board should be intact, no damage and crack, and has the appropriate tightness. 4, steel plate shall not constitute a closed loop, should be a little ground at the same time; 5, open the clip on the pieces and the connection between the core and steel clamp and the clamp on a connection piece, measuring core and clip pieces and steel plate between the up and down between the core and insulation resistance, compared with the previous test should be no obvious change; 6, bolts, is positive and back pressure on the screw and lock nut loose, contact with the insulation gasket is good, no discharge burns, back pressure on the nail and clip pieces have enough distance; 7, wear heart bolts, its insulation resistance compared with the previous test has no obvious change; 8, oil should be open, oil block without loss and congestion, and should be neatly; 9, core allows only a little grounding, grounding piece with the thickness of 0. 5 mm, the width is not less than 30 mm of copper sheet, insert between 3 ~ 4 core, for large transformer insertion depth of not less than 80 mm, the exposed portion should be bandaged insulation, prevent short circuit core; 10, should tighten and have enough mechanical strength, good insulation, and does not constitute a loop does not contact with iron core; 11, good insulation, reliable grounding.