The blue book revision committee for the 2017 edition consisted of the following employees. It explains basic ac circuit concepts, transformer formulas, nameplates, preinstallation checks, singlephase connections, fusing, grounding, load checks, vector diagrams, delta and wye connections, phasing and parallel. Instructions for oilimmersed distribution t ransformer s. The area 1 foot around and 6 feet below the pad or pedestal shall be kept free of foreign substructures. The revision of this book was made possible due to the suggestions and efforts of many employees. They are often used in underground electric network areas. Wellillustrated, this reference helps everyone install and maintain transformers correctly, quickly, and safely. Types of single phase pad mounted transformers type 1 and type 2. Pad mounted transformers are used with underground systems. It is intended for the use of customers, architects, engineers, contractors. Typical padmounted transformer introduction eaton s threephase padmounted.
Howard industries liquidfilled threephase pad mounted transformers are an excellent choice for any commercial or industrial underground distribution system. Kfactor rated transformers are offered for the entire product scope. A padmount transformer is a groundmounted utility distribution transformer, which usually is housed in a locked metal cabinet, situated on a small concrete pad. Additional for additional copies of the 2014 electric service manual, contact your company copies of the representative. Go to envirotran solar and energy storage threephase pad mounted transformers. Basics, maintenance, and diagnostics vii contents continued page 4. It is used wherever 3phase building loads are served by an underground mv distribution system. Ge prolec three phase padmounted transformers are shipped hermetically sealed.
Operation and maintenance requirements for services above 600 volts pdf, 166kb electric system bulletin no. These transformers typically serve urban and rural residential, commercial and industrial loads. An ocpd is required for the transformer primary conductor. Distribution transformer handbook is packed with practical information on transformer concepts, singlephase and threephase transformer connections, and procedures for installing overhead and padmount transformers. It does not apply in a network area, or in urd ucd. Transformer connection worksheets are also available. For pad mount transformers, the number of secondary service connections is limited to the maximum as shown on the tables in drawing 17. A distribution transformer or service transformer is a transformer that provides the final voltage transformation in the electric power distribution system, stepping down the voltage used in the distribution lines to the level used by the customer.
The recommended pad size should be 46 minimum larger than the switchgear footprint shown in the assembly drawing andor product brochure. All units are manufactured in accordance with applicable ieee standards. Deenergize the transformer before attempting to remove internal fuses. Effective date april 15, 2015 3 introduction xcel energy is dedicated to providing safe, economical, and reliable service to its customers. Clearances and location requirements for enclosures, pads, and underground equipment 051122 page 4 of 28 rev.
Pad mounted transformers are designed to be mounted on concrete pads. Transformer primary feeder protection the nec does not list any specific exception for transformer primary feeder protection. Padmount transformer explained the electricity forum. Highfire point fluid, such as silicone, hydrocarbon or vegetable fluids. Ansi singlephase pad mounted transformers come equipped with a clamshell cabinet for ease of opening and uninhibited access to connections. The selfcooled three phase pad mounted transformers depend entirely on the air that circulates in their. Transformer oem equipment singlephase overhead singlephase pad mounted threephase pad mounted threephase substation transformer fusing 2016 u. Specifications for electrical installations 2020 covering national grids service areas in massachusetts ma, new york ny and rhode island ri. Single phase pad mounted transformer deferred unit. Padmount transformers are becoming more popular because the higher cost of. Singlephase padmounted distribution transformer 86.
Note the fused cutout and lighting arrestor combination external to the transformer. If electric service is being supplied from an existing transformer, the customer shall end the secondary duct five feet from the secondary. Standard for electric installation and use xcel energy. Do not raise the transformer from drain valves, pipeline connections nor. Go to envirotran threephase pad mounted transformers. Outdoor pad mounted or vault enclosed three phase transformer, commercial pdf, 1mb electric system bulletin no. A padmount or padmounted transformer is a ground mounted electric power distribution transformer in a locked steel cabinet mounted on a concrete pad. A padmount transformer is a ground mounted utility distribution transformer, which usually is housed in a locked metal cabinet, situated on a small concrete pad. Threephase, padmounted distribution transformers for underground service. Padmount liquid filled transformers for use on underground power distribution systems. When a load is connected to the secondary winding of the transformer, a current. Pme pad mounted gear, for outdoor distribution, 14. Instructions for oilimmersed distribution transformers. Choose transformer type you are considering and the extended ratings you are considering.
Instructions for oilimmersed distribution t ransformer s section d. Pdf distribution transformer handbook oscar mayorquin. Ermco pad mounted transformers are shipped filled with insulating transformer oil. Immediately upon receipt, and before being put into service, transformers should be carefully inspected for any external damage or loose parts caused by shipping and handling. Transformer book is still in demand is a tribute to the publishers and to the authors who have carried the torch to light our way for 75 years. Livefront mes and deadfront mds padmount switchgear. Eatons cooper power series transformer products are iso 9001 compliant, emphasizing process improvement in all phases. This illustrated field reference helps everyone install and maintain transformers correctly. Since all energized connection points are securely enclosed in a grounded metal housing, a padmount transformer can be installed in places that do not have room for a fenced enclosure.
Therefore, our employees are instructed and obligated to require adherence to these standards and procedures. Transformers for linemen covers everything a lineman needs to know about distribution transformers. Three phase padmounted and unit substation transformers 453000 kva total customer satisfaction through continual process improvement. Electric service guidelines oncor electric delivery. Distribution transformer handbook is packed with practical information on transformer concepts, singlephase and threephase transformer connections. Oil must be at the proper level before voltage is applied to the transformer.
Illustrates for electrical engineers the relevant theories. A padmounted connection enclosurepecified, installed, swned and lockedseale o d by company, located adjacent to company transformered to us connect customers service conductors that are in excess an in numberd cannot normally andor size, beaccommodated by transformer. It is essential that the pad or foundation be level to avoid distortion of the switchgear structure and the equipment be properly aligned prior to final anchoring. The first half of the book explains basic principles and singlephase transformers. Meter installationandpadmount transformer guide feb. A padmount transformer is a tamper proof distribution transformer with lockable front doors that is installed on a concrete pad. All prior specifications that conflict with the specifications in this book cease to be effective on january 1, 2017, and work done to those specifications including all specifications contained in the. Distribution transformer handbook is packed with practical information on transformer concepts, single and threephase transformer connections, and approved procedures for installing overhead and padmount transformers. Padmount liquid filled transformers schneider electric. Both polemount and padmount transformers convert the high primary voltage of. Padmounted distribution transformers small distribution.
An electronic version of the 2014 electric service manual is also electric available online at. T h e unit should not be tilted in any direction greater than 1. Reception, installation, operation and maintenance. See document 043818 or document 045292 for transformer pad dimensions. At nominal secondary voltage based on infinite primary bus sc mva motors can contribute to sc current. The first half of the book explains basic principles and single phase transformers. A padmount or pad mounted transformer is a ground mounted electric power distribution transformer in a locked steel cabinet mounted on a concrete pad. The three phase padmounted distri bution tra n s fo rmer is designed to provide electrical. Therefore, for actual values, obtain nameplate impedance from owner or manufacturer. It is recommended to install pad mounted transformer, bus duct entrance termination box, and customer bus duct entrance box on the same monolithic pad to avoid soil settlement issues. Distribution regional warehouse stocks have been implemented across the united states, ensuring. Their assistance and support is acknowledged and appreciated.
This standard provides recommended barrier protection for pad mounted equipment subject to vehicular traffic. Connections between company and customer 12 inspections 12. The percent x and percent r values are desirable for calculation. The three phase pad mounted transformer location should provide enough space. Department of the interior bureau of reclamation technical service center infrastructure services division hydroelectric research and technical services group. Damage presumed to have occurred during shipment should be noted, and your. Single main service panels fed by single transformer example 1. Ermco single phase pad mounted distribution transformers are designed and manufactured in compliance with all applicable ansi and rus standards. Example of a pad mount installation with ct provisions and lockable. Always size the transformer pad to accommodate the largest transformer size necessary to serve the combined ampacity of all services. Threephase pad mounted compartmental type transformer general at eaton, we are constantly striving to introduce new innovations to the transformer industry, bringing you the highest quality, most reliable transformers. Threephase padmounted compartmental type transformer general at eaton, we are constantly striving to introduce new innovations to the transformer industry, bringing you the highest quality, most reliable transformers. It is the responsibility of the installer and user to. What id the difference between a pad mounted, pole mounted.
Effective date april 15, 2015 the customer shall provide a minimum of ten 10 feet level clearance on the door sides of pad mounted transformers for hotstick operation and ten 10 feet level clearance on the door sides of padmounted primary metering cabinets for instrument transformer maintenance. Typically used in commercial and residential areas to connect to underground electric power lines safely and securely, padmount transformers do not require a fencedin enclosure, making them ideal for public spaces like shopping malls, restaurants, and other areas. The tr a n s fo r mers should be mounted on a flat level pad strong enough to support the weight of the tr a n s fo rm e r. Never exceed more than seven sets of conductors per transformer. The transformer is always connected to the primary distribution lines through protective. Vacant ducts, if any, will be used to serve future load increases. Reception, installation, operation and maintenance manual for. Uniform enforcement of these standards throughout the company will expedite service connections and treat each of our customers equally and fairly. Section 1 foreword, general information, and terms 1. Typical applications include manufacturing facilities, refineries, office buildings, schools, hospitals, restaurants, warehouses, and retail stores. Information and requirements for the supply of electric service, or silver book on or after that date will not be.
Nec guidelines for transformer and transformer feeder. Padmounted, 3phase distribution transformershereafter referred to simply as are typically pm transformers used in the mv ac collection system of a pv power plant. The pad mounted transformer is designed for underground service and for outdoor mounting on a concrete pad. Keep this instruction book available to those responsible for the installation. Since all of the live contact points are enclosed in a. These distribution transformers are normally located in residential subdivisions.
Eaton s cooper power series transformer products are iso 9001 compliant, emphasizing process improvement in all phases. The emphasis is on overhead transformers but padmount transformers are. Pad mounted transformers are usually threephase weight is less of a concern, and they are generally intended for use in applications with the high and low voltage cables enter the transformer from below such as in underground distribution applications. Posts may be omitted on side s not subject to vehicular traffic. Livefront mes and deadfront mds padmount switchgear instruction bulletin. Abb offers a complete range of distribution transformers designed to grant the reliability, durability, and efficiency required in utility, industrial, and commercial applications. The appropriate number of bushings, loadbreak elbow terminators and surge arresters shall be provided as specified in section iv. Clearances and location requirements for enclosures, pads, and underground equipment 051122 page 6 of 28 rev. If overload protection of the ocpd would create a power loss hazard, such as fire pump application and some. It explains basic ac circuit concepts, transformer formulas, nameplates, preinstallation checks, singlephase connections, fusing, grounding, load checks, vector diagrams, delta and wye connections, phasing and paralleling banks, troubleshooting, and how to energize transformers safely. Nodak will assist with overhead transformer connections. Discover delightful childrens books with prime book box, a subscription that delivers new books. Pseg li for deadfront, single phase padmount transformers ranging in size from 25 kva to 167. Failure to comply may result in serious personal injury or damage to the equipment.
The emphasis is on overhead transformers but padmount transformers are covered also. High voltage 24,940 grdy14,400 volts and below, 2500kva and smaller. This book represents the present policies and objectives of the georgia power company within the revenue. A distribution transformer or service transformer is a transformer that provides the final voltage. Submersible singlephase distribution transformers fig. It is the policy of the company to serve all its customers in an orderly. The transformer is designed for outdoor mounting on a pad. The three phase padmounted distr i b ution tra n s fo r mer is designed to provide electrical service on underground distri b u t i o n systems. Among the materials consulted while preparing this book are. It is the responsibility of the installer and user to ensure that the interface between the pad and transformer, including the cable compartment, is properly sealed so that foreign objects can not be inserted inside the cable compartment. Padmount transformers medium voltage elsco transformers.
Morgan lacey in 1925, based on a series of pamphlets entitled transformer abstracts that were. Pseg li shall deliver the transformer and set it onto the concrete pad. They offer the maximum amount of tamper resistance in the lowest profile design. Threephase padmounted transformers ge grid solutions. C rise, and designed for usual service conditions per ansi c57. Three phase padmounted and unit substation transformers.
Since all of the live contact points are enclosed in a grounded metal box, this kind of transformer can be situated in residential locations and do not need to be fenced, like transformers. An external fusecutout combination is mounted between the distribution primary and the conventional transformer. Green industrial 300 kva padmount transformer hv 12470 delta lv 480 y 277 ge new in 2007 w taps duration. This combination provides both voltage transformation and transformer overcurrent protection in one spacesaving and money saving package.