Transformers

The standard sets out requirements for the design, construction and verification of electrical installations, including the selection and installation of electrical equipment forming part of such electrical installations. These requirements are intended to protect persons, livestock, and property from electric shock, fire and physical injury hazards that may arise from an electrical installation that is used with reasonable care and with due regard to the intended purpose of the electrical installation.

There are various sub standards (6-1, 6.-2, etc.) that apply to EMC. Information from IEC 61000-6-1 covers EMC immunity requirements for electrical and electronic apparatus intended for use in residential, commercial and light-industrial environments. Immunity requirements in the frequency range 0 Hz to 400 GHz are covered. No tests need to be performed at frequencies where no requirements are specified. This generic EMC immunity standard is applicable if no relevant dedicated product or product-family EMC immunity standard exists.

NFPA 70E requirements for safe work practices to protect personnel by reducing exposure to major electrical hazards. Originally developed at Occupational Safety and Health Administration (OSHA)’s request, NFPA 70E helps companies and employees avoid workplace injuries and fatalities due to shock, electrocution, arc flash and arc blast, and assists in complying with OSHA 1910 Subpart S and OSHA 1926 Subpart K.

The standard provides electrical and mechanical requirements for liquid-immersed distribution and power transformers, and autotransformers and regulating transformers; single- and polyphase, with voltages of 601 V or higher in the highest voltage winding, are set forth. It is basis for the establishment of performance, and limited electrical and mechanical interchangeability requirements of equipment are described, and for assistance in the proper selection of such equipment.

1.1 These requirements cover the following types of transformers:

1. Air-cooled transformers and reactors for general use;
2. General purpose autotransformers;
3. Ferroresonant transformers;
4. Class 2 and Class 3 transformers (which are evaluated in accordance with Part 3);
5. Cord-connected transformers (which are evaluated in accordance with Part 2);
6. Transformers incorporating overcurrent or over-temperature protective devices, transient voltage surge protectors, or capacitors; and
7. Permanently-connected transformers.

1.2 These transformers are intended to be used in accordance with the National Electrical Code, ANSI/NFPA 70, or CSA C22.1, the Canadian Electrical Code, Part I. The Canadian Electrical Code defines low voltage as any voltage from 31 to 750 V inclusive and high voltage as any voltage above 750 V. The National Electrical Code, ANSI/NFPA 70, defines low voltage as any voltage up to 600 V, nominal. Therefore, low voltage transformers intended for use in Canada may be rated above 600 V up to 750 V. Low voltage transformers intended for use in the United States are rated up to 600 V. Where information in clauses and tables in this standard reference voltage ranges, the limit of 600 V applies in the United States, while the limit of 750 V applies in Canada.

1.3 The standard does not cover the following transformers:

1. Direct plug-in types;
2. Neon;
3. Liquid-immersed;
4. Variable voltage (Variac);
5. Low voltage landscape;
6. Swimming pool and spa:
7. Ignition;
8. High intensity lighting;
9. Toy;
10. Fluorescent lamp types;
11. Transformers for welders;
12. Distribution;
13. Transformers intended for use in the United States with a nominal primary rating of more than 600 V;
14. Transformers incorporating rectifying or waveshaping circuitry;
15. Transformers for use with radio- and television-type appliances;
16. Transformers intended for use in the United States having overvoltage taps rated over 660 V;
17. Autotransformers used in industrial control equipment, which are evaluated in accordance with the requirements of the Standard for Industrial Control Equipment, UL 508, or CSA C22.2 No. 14, Industrial Control Equipment; and
18. Other special types of transformers covered in requirements for other electrical devices or appliances.

1.4 Part 1, as well as Part 2 and Part 3, establish the characteristics, construction, operating conditions, markings, and test conditions for each type of transformer.

1.5 The requirements in this standard may be modified by requirements in an end product standard if a transformer is intended for use only as a component in other equipment.

1.1 This Standard applies to all liquid-filled power transformers, except those types listed in Clause 1.3, and specifies minimum efficiency ratings. The minimum efficiencies specified are for transformers at their base kVA rating, as described in Tables 1 to 3. Minimum efficiencies are also specified for some special designs (Clause 4.3). 1.2 This Standard applies to power transformers rated from 501 to 10 000 kVA and operating with a 60 Hz waveform and does not include the effect of any harmonics.

1.1 This Standard specifies the mechanical and electrical characteristics of three-phase network distribution transformers having rated primary voltages up to 34.5 kV and kV-A ratings of 500 to 2500 Note: It is possible that transformers complying with this Standard will, if operated by a body other than an electric utility, be subject to additional requirements imposed by the electric inspection authority having jurisdiction. 1.2 This Standard applies only to three-phase distribution transformer units intended for use in a ventilated vault or enclosure below grade level.

1.1 This Standard applies to single-phase and polyphase transformers of the dry type for supplying energy to power, heating, and lighting circuits and designed to be installed and used in accordance with the Canadian Electrical Code, Part I. 1.2 This Standard applies to multiwinding and autotransformers rated 72.5 kV class and less. 1.3 This Standard applies to transformers for use in nonhazardous indoor and outdoor locations.

Intended Use
The objective of Standards issued as part of the Canadian Electrical Code, Part II, is to give consideration to the prevention of injury to persons and damage to property through proper design, good construction, and high quality of work. These safety Standards are intended to provide requirements for the design and construction of electrical equipment, primarily to address fire and electrical shock hazards and for use throughout Canada in conformity with the rules of the Canadian Electrical Code, Part I.

Description: Considered in this guide are the components of both the ac and dc systems and the provided guidelines and recommendations for designing the appropriate systems for the substation under consideration. This guide includes the low-voltage auxiliary systems from the source(s) to the distribution point(s). Reliability requirements and load characteristics are discussed and distribution methods are recommended.