CSA C227.3-06 pdf download – Low-profile, single-phase, pad-mounted distribution transformers with separable insulated high-voltage connectors.
2 Reference publications and definitions 2.1 Reference publications This Standard refers to the following publications, and where such reference is made, it shall be to the edition listed below. CSA (Canadian Standards Association) C22.2 No. 0.1 5-01 Adhesive labels CAN/CSA-C50-97 (R2001 ) Insulating oil, electrical for transformers and switches CAN3-C1 08.3.1 -M84 (R2005) Limits and measurement methods of electromagnetic noise from ac power systems 0.1 5–30 MHz CAN/CSA-C802.1 -00 Minimum efficiency values for liquid-filled distribution transformers CAN/CSA-ISO 9001 -00 (R2005) Quality management systems — Requirements W47.1 -03 Certification of companies for fusion welding of steel W59-03 Welded steel construction (metal arc welding) ANSI (American National Standards Institute) C37.72-1 987 Manually-Operated, Dead-Front Pad-Mounted Switchgear with Load Interrupting Switches and Separable Connectors for Alternating-Current Systems C57.1 2.28-2005 Pad-Mounted Equipment — Enclosure Integrity ANSI/IEEE (American National Standards Institute/Institute of Electrical and Electronics Engineers) C57.1 2.25-1 990 Transformers — Pad-Mounted, Compartmental-Type, Self-Cooled, Single-Phase Distribution Transformers with Separable Insulated High-Voltage Connectors; High Voltage, 34 500 GrdY/1 9 920 Volts and Below; Low Voltage, 240/1 20 Volts;
2.2 Definitions The following definitions apply in this Standard: Additive polarity — polarity in which the adjacent high-voltage and low-voltage terminals are connected together as shown in Figure 1 , and a suitable voltage is applied to the high-voltage winding between terminals H1 and H2. The voltage measured between the open adjacent terminals H2 and X1 is greater than that applied to the high-voltage winding between terminals H1 and H2. Cable entrance compartment — a metal enclosure that is open at the bottom for cable entry. The enclosure consists of a hood and sill, both removable from the front of the transformer tank. Effectively grounded — grounded in such a way that, under line-to-ground fault conditions, the rms voltage-to-ground of the ungrounded phase cannot exceed 80% of the normal phase-to-phase voltage. Exciting current — the current that flows in any winding used to excite the transformer at 1 05% of rated voltage when all other windings are open-circuited. It is usually expressed as a percentage of the rated current of the winding in which the current is measured. Impedance voltage — the voltage required to circulate rated current through one winding of the transformer when the other winding is short-circuited, the respective windings being connected for rated voltage operation. It is usually expressed as a percentage of the rated voltage of the winding in which the voltage is measured. KNAN — insulating liquid with a fire point greater than 300 °C.
Tamper-resistant — the state in which, in any normal operating condition, contact with live parts cannot be made either directly or by means of any conductive material, with or without the use of such common tools as might be accessible to children. It does not imply proof against any deliberate actions of adults and children. Turns ratio — the ratio of the number of turns in the high-voltage winding to that in the low-voltage winding. Weather-resistant — the state in which, in any normal operating condition, flanges, covers, doors, etc., are fitted so as to prevent entry of sufficient moisture or dust to reduce the effective flashover or creepage-withstand strength of insulators, barriers, or cable terminations under conditions of driving rain, snow, or dust. Where dust conditions are severe, periodic cleaning may be required. 3 Quality assurance Transformers shall be designed and manufactured in accordance with a quality program acceptable to the purchaser. Note: An example of an acceptable quality program is a quality program registered by a certified registrar to CAN/CSA-ISO 9001. 4 Electrical characteristics 4.1 kV•A ratings The kV•A ratings at rated voltages shall be 25, 50, 75, 1 00, and 1 67.
4.2 Temperature rise 4.2.1 Temperature rise limits as given in Clause 4.2.2 shall not be exceeded when the transformer is operating continuously at rated kV•A and when connected to the rated voltage tap. When there are alternative connections other than tap connections for any windings, the temperature limits specified shall apply to the connection that produces the highest temperature rise. 4.2.2 When measured by resistance, the average temperature rise of each complete winding above ambient temperature shall not exceed 65 °C. The calculated hottest-spot winding temperature rise shall not exceed 80 °C. The temperature rise of the insulating oil shall not exceed 65 °C when measured near the top oil level.CSA C227.3-06 pdf download.
