Storage, assembly and maintenance instructions. 24 kv-72.5 kv A CERAMIC BUSHING INSULATIONS. 12 kv 52 kv 250 A 8000 A

Transcription

1 CERAMIC BUSHING INSULATIONS Storage, assembly and maintenance instructions 24 kv-72.5 kv A 12 kv 52 kv 250 A 8000 A

2 Ceramic bushing insulators 12 kv 52 kv 250 A 8000 A General information These instructions are applicable to ceramic bushing insulators with rated voltages from 12 kv to 52 kv and rated currents from 250 A to 8000 A. These bushings are designed to operate with the upper part in air (pollution level up to P4) and with the lower part immersed in the transformer oil. Ceramic bushing insulators have been designed and produced in conformity with the standard IEC The specifications, dimensions and description are stated in the catalogue. Packaging All ceramic bushing insulators are shipped inside a cardboard box positioned on a pallet to facilitate transport and storage. Acceptance Upon receiving the bushing, the Customer must carry out the following operations: examine the outer surface of the packaging to check that it is intact; open the packing crate removing the lid ; check that the fastening elements are intact and well secured; check that there are no breakages. If any damages are found, please contact, quoting the data provided in the shipping list Montebello Vicentino (VI) Italy Tel info@comem.com Page 2

3 Rating plate data The rating plate data is indicated on each ceramic bushing insulator in accordance with the standard IEC 60137: name of manufacturer, rated voltage U m, rated current I r, year of manufacture. Storage The ceramic bushing insulator must be stored in the original packaging indoors. Permissible storage temperatures are in the range of -25 C to 60 C. Lifting The ceramic bushing insulator has sturdy packaging; nonetheless, some precautions must be taken during handling to prevent damaging the insulation bushing. Packaged insulation bushing: the ceramic bushing insulator must be handled using the pallet. Insulation bushings out of the crate: to remove the insulation bushing from the crate screw an eyebolt tightly into the upper end of the conductor. The rope for lifting the bushing must be fastened to the eyebolt so that the bushing cannot be damaged during transport. The best position for transport out of the crate is vertical. The bushing must not be handled using the sheds, as this could compromise correct operation. Page 3

4 Operating conditions Altitude: ceramic bushing insulators can be used up to an altitude of 1000 m. For installation at higher altitudes please contact Ambient air and immersion medium temperature: ambient air: maximum 40 C, daily average: maximum 30 C, minimum -25 C, transformer oil: maximum for normal load: 100 C daily average: maximum 90 C Temporary over-voltages: according to the standard IEC Assembly on the transformer box For correct installation of the ceramic bushing insulator follow the procedure below: 1. Make a hole with diameter D1 (see Table 1) in the transformer box, ensuring there are no uneven surfaces that could cause problems for correct operation of the bushing. 2. The stud bolts for securing the bushing (see Table 1) must be placed along a circumference of diameter D2 coaxial with the hole made previously (Figure 1). 3. Position the gasket provided standard (Figure 1). 4. The bushing must be positioned as shown in Figure 2, apply a tightening torque of 15 Nm with stud bolt M10 and 25 Nm with stud bolt M12 to the fixing nuts of the flange (Figure 2). Figure 1 Figure 2 Page 4

5 Voltage (kv) Current (A) Standard Flange Diameter of the hole D1 (mm) Number Thread Stud bolts Diameter D2 (mm) Max height (mm) DIN DIN DIN EN A 80 4 B 80 3 M DIN EN A 6 90 B DIN DIN COMEM DIN COMEM DIN EN M EN EN Table 1 5. The internal insulation shall be filled with oil, so it should come out from the top of the isolator until the air is leaking oil, this can be done through the bleed screw in this insulators larger (figure 3), or smaller ones acting on the hood (figure 4). At the end of this screw the nut over the bolt (figure 3-4) by applying the torque recommended in table 2.

6 6. Optional: spark gap are the horns to be mounted with all accompanying materials as in figure 5 Flag Nut Vent screw Cap Nut Cap Figure 3 Figure 4 Figure 5 Page 6

7 Connecting the cables After carefully choosing the section of the connections to be used, connect them applying the torque recommended in Table 2 as a function of the rated current. Care must be taken over electrical connection to avoid ionization phenomena. In the event that the wires are attached with a terminal connector (Figure 3), we must tighten it so that the whole thread is tightened, then tighten the bolts with a torque as in Table 3. The pair of bolts is determined by the class strength of the bolt, making sure that the connection does not cause overheating. Rated current (A) Nominal torque (Nm) Thread of bolt Nominal torque (Nm) M8 12 M10 15 M12 40 M16 90 Table Table 2 Should it become necessary to disconnect the connections, please loosen the nut to be removed while holding the counter-nuts clamped to avoid damage. Page 7

8 Cleaning Cleaning of the sheds during periodic maintenance of the transformer is recommended. If the bushing has a high level of pollution due to the environment in which it is installed, we recommend cleaning by rubbing the entire surface with a soft sponge soaked in a solution of soap and water at 50 C. The bushing must then be rinsed thoroughly with tap water. Moreover, we recommend cleaning of the sheds at more frequent intervals. Page 8

9 Troubleshooting If malfunctions should occur during normal operation, please consult the following table: Fault Oil loss from the flange of the bushing Oil leaking from the top of the bushing There are hissing noises at the flange There are hissing noises at the connection in air Electric discharge at the air end outside the bushing Abnormal distribution of temperatures in the bushing. Physical phenomenon Leakage Leakage Corona effect Corona effect Electric discharge Thermal effect Solutions Tighten the stud bolts to the recommended torque. Check correct positioning of the gasket. Check the surfaces of the box have no uneven parts or excessive roughness. Better tighten the nut on the hood bushing (figure 3 and 4) Check the voltage applied The correct assembly of the bushing. Check oil inside the bushing insulator. Check whether the conductor connected to the bushing has any edges that cause increased electric field density. The correct assembly of the bushing Check the connection at the air end of the bushing. Check cleanliness of insulating surfaces. Check the connections applying the torque recommended in Table 2. Check that the section of the conductors for connection to the bushing is correct. If the problem is not mentioned in the cases above, please contact: Montebello Vicentino (VI) - Italy Page 9