CSA C301.1-06 pdf download – Single-phase submersible distribution transformers.
4.2 Sealed construction 4.2.1 The complete transformer assembly shall be of sealed construction and shall remain effectively sealed for a top oil temperature range of –40 to 1 05 °C. 4.2.2 Provision shall be made on all units for the manual release of gas pressures, before servicing, by means of a valve or plug. 4.3 Lifting lugs Lifting lugs shall be provided. 4.4 Tanks Tanks for transformers up to and including 1 00 kV•A shall not have external cooling devices. External tank walls shall be smooth to minimize corrosion and to reduce the possibility of damage to the protective coating. 4.5 Handhole If a welded cover is supplied, a handhole shall be provided for tap changing or inspection purposes. The handhole shall be of adequate size and located in the cover.
5 Bushings, terminals, and grounding 5.1 Bushings and terminals 5.1.1 Each transformer shall be supplied with terminals and an accessory parking stand located as shown in Figure 1 . The accessory parking stand shall be for load-break accessories unless otherwise specified. 5.1.2 Two high-voltage bushing wells shall be provided for connection to the distribution system through separable insulated connectors. The bushing wells shall be in accordance with IEEE 386. The minimum current-carrying capability of components for the looped primary cable system shall be 200 A continuous and 3500 A symmetrical (3 s). 5.1.3 The H2 end of the winding shall be electrically connected to the tank or cover internally by a bolt-type connection. This connection shall be located so that, in accordance with Clause 5.2.1 , it is visible and accessible when the tank or handhole cover is removed. It shall be independent of all other connections except in the case of non-metallic tanks. The H2 lead shall be connected to the internal ground, which shall be continuous through the tank or cover to an external ground. 5.1.4 Three low-voltage tinned copper spade terminals, as shown in Figure 2, shall be provided unless otherwise specified by the purchaser. The terminals may be located on the tank wall or on the cover. All low-voltage terminals shall be insulated from ground. Note: The purchaser is responsible for wrapping or otherwise encapsulating connections to the spade terminal to maintain the submersible characteristics of the unit.
5.1.5 When low-voltage cable bushings are requested by the purchaser as an option, they shall extend a minimum of 600 mm above the top of the cover. Cable insulation shall be cross-linked polyethylene for power cables rated 600 V, in accordance with CSA C22.2 No. 38, for continuous operation at 90 °C maximum. Cable shall be stranded copper, as shown in Table 2. 5.1.6 Cables shall be sealed to prevent oil siphoning from the transformer or moisture ingress from air. 5.1.7 Bushing wells shall include provision for attaching holding devices to keep separable high-voltage insulated connectors in place. 5.1.8 The disconnecting features between the high-voltage bushing and cable termination shall either be load-break or dead-break, as specified by the purchaser. 5.1.9 Electrical characteristics of completely assembled high-voltage terminals shall be in accordance with Table 3. 5.1.10 Each high-voltage bushing shall be equipped and shipped with a protective cap suitable for outdoor storage. 5.2 Grounding 5.2.1 Tank grounding connector Two corrosion-resistant external grounding connectors shall be provided on the cover or on the tank wall within 20 cm of the cover. The location of the two connectors shall be in accordance with Figure 1 . Each connector shall be mounted to a stainless steel boss or spade and shall be suitable for accepting a range of conductors from No. 6 solid to No. 2/0 stranded AWG copper. The bosses shall have a minimum projection of 1 2 mm and shall have a 1 /2 in – 1 3 threaded hole.CSA C301.1-06 pdf download.
