Pdf power transformers principles and applications. There is the potential of electric shock whenever working in or around electrical equipment such as transformers. Power transformer maintenance and acceptance testing on photo. Operation, maintenance and condition monitoring practices for long service life of transformers. Water content measure the water content using karl fisher method. As such it is desirable to perform various preventative maintenance activities to ensure the transformer maintains a high level of performance and a long functional life. Operation, maintenance, and field test procedures for. Power transformer maintenance includes periodic electrical testing of different parameters of the transformer, being common the periodic checking of some key magnitudes such as turns ratio, excitation current, polarization index, insulation resistance, tandelta, winding resistance, short circuit impedance, etc. Smaller transformers can be directly installed on the wall but still need to be mounted at least 12 in. Predictive power transformer maintenance as an effective maintenance system.
The emphasis has been given to include the operation and maintenance procedures of new and modern technology for substation equipments and protective relays. As any other electrical equipment, transformers must be installed according to the requirements of all applicable national and local electrical codes. Maintenance instructions for power transformers maintenance schedule sl no inspection frequency items to be inspected to be checked action required if inspection shows unsatisfactory conditions 1 hourly ambient temperature 2 hourly winding temperature ensure that temperature rise is within specified limits. In this contribution we introduce diagnosis and condition based maintenance programs for power transformers. Power transformer working principle, construction and. Nameplate ratings voltagepower of the transformer matches the site requirements. Loading considerations when paralleling transformers it can be seen by using equations 1 and 2 below, that if the percent impedances in each transformer are the same, as shown in figure 1, that there will be equal current division and load sharing on each transformer. Transformers are the key link in any power distribution system and likely the least understood. This has led the utilities to adopt conditionbased maintenance of the equipments rather than usual preventive maintenance being carried out at a fixed interval of.
Medium voltage products unisec operation and maintenance. This transformer training course provides a comprehensive overview of electrical transformers found in the industry. Installation, application, operation and maintenance of drytype general purpose distribution and power transformers. Operation, maintenance, and field test procedures for protective relays and associated circuits iii acronyms and abbreviations a ampere ac alternating current amp ampere ansi american national standards institute bes bulk electric system carma capital asset and resource management application ccvt coupling capacitor voltage transformers co. Ventilated style power transformers are 600 volt class units with ventilated enclosures for natural draft cooling. An understanding of the fundamental theory and principles of the operation of power transformers. The transformer is one of the most reliable pieces of electrical distribution equipment. Power transformer maintenance operation at only 10% above the transformer temperature rating will cut transformer life by 50% transformer heating by. Installation, operation, and maintenance guide low voltage transformers 4 performing the modifications will be solely liable. Figure 33 routine maintenance management process 3. The purpose of this maintenance manual is to provide guidance on required and recommended maintenance of liquid.
The information contained herein outlines and describes the proper inspection, installation and maintenance of dry type transformers. Power transformers must be inspected regularly so that problems can be detected early and corrected before major repairs are needed. Both strategies can be of a preventive character, consisting of regular inspections, regular maintenance like retightening of gaskets and predefined component. Failure to follow instructions may result in death or serious injury. Operation of the switchgear is illustrated in this manual and the instructions for replacing and mounting new apparatus are also given. Then we can say that primary power equals secondary power, p p p s.
Power transformer maintenance and acceptance testing. A transformer has two or more separate coil windings placed on a common magnetic core. Transformer basics and transformer principles of operation. Austin energys substation maintenance power transformer hot oil processing and vacuum filling. It is targeted to those involved in the installation, operation and maintenance of electrical power systems. For the purpose of scheduling, each task has a due date and associated maintenance plan float time period within which the work must be completed. Always use appropriate personal protective equipment ppe. Due to electrical potential that exists within all dry type transformers, input power must be disconnected before any work is performed. Careful attention to the following instructions is recommended for safe and reliable operation. These activities will increase the transformerss service lie and help to make the transformers operation both safe and troublefree. For additional information, contact your eaton representative.
A power transformer requires various routine maintenance tasks including measurement and testing of different parameters of the transformer. New approaches for transformer operation and maintenance technology advancements and new regulatory requirements could reshape how power plant owners operate and. With an understanding of the construction and maintenance of transformers, you will be able to make informed decisions about the performance and operation of this costly piece of equipment. The first one deals with preventative maintenance of substation equipment and protective switchgears. All work should be preformed in accordance with nfpa 70e standard for electrical safety in the workplace and csa z462, workplace electrical safety. Substation transformer installation, operation and maintenance. In the uk this was, until january 1995, 415 v threephase and 240 v phase to neutral. Department of energys federal energy management program femp. The mission of femp is to facilitate the federal governments implementation of sound, cost. A power transformer is the most costly and essential equipment piece of equipment within an electrical substation. The power source was a 25hp steam engine driving an alternator with an output of 500 v and 12.
But the primary coil winding is responsible for supplying the alternating current ac with supplied frequency and it produces the magnetic flux. This manual contains a generalized overview of the fundamentals of transformer theory and operation. Pdf guide for transformer maintenance guide for transformer. Installation, operation and maintenance of transformers should be performed by qualified persons, familiar with electrical apparatus and the potential hazards involved. Also, accessibility for maintenance needs be taken into account in locating a transformer. In todays competitive market scenario power utilities are under tremendous pressure to cut down their maintenance costs as they form a significant portion of the operation costs. Maintenance based on the control of the performances of an element andor the main parameters for its operation and based on the control of the corrective actions consequently taken. It includes details about the units and service conditions. An insight into the identification and application of. Users manual operation and maintenance for power transformers. Though the operation of a transformer may look simple, it is necessary to understand the basic functioning of a.
Although this means that the magnitude of the load loss is not too important, iron loss is present all. In any case, it must be verified the degree of dust and salt, the quality of the water to wash and the method of. Second part deals with preventative maintenance of transmission lines. Pdf power transformers are important and expensive components in electric. Power transformer installation, acceptance, and maintenance procedures.
Substation transformer installation, operation and. This can be done by adopting timely preventive maintenance schedule regarding all vital areas of the power project. Transformer operation the transformer is connected to the electrical system and a. Although the transformer can stepup or stepdown voltage, it cannot stepup power. Electrical potentials hazardous to human life can exist within this equipment when energized. Transformer preventative maintenance involves routine inspection, adjustment, testing, minor fixes, and special handling instructions. Proper operation and maintenance to ensure continuous service. We perform one group on a routine basis known as preventative maintenance, and the second group on an adhoc basis i.
The next step is to operate transformers so that they are not operated beyond their temperature ratings and limits. Basics, maintenance, and diagnostics vii contents continued page 4. Drytype transformers are manufactured to provide optimum performance for a lifetime of uninterrupted service. The politic change in some companies had a great influence in maintenance and operation works in their electric machines. Internal losses due to loading high ambient temperature solar radiation fortisalberta makes use of onanonafonaf cooling systems on. Disconnect all input power before opening case or touching internal parts. Protecting the transformers while in service to keep outages to a minimum. Both ventilated cabinet style and encapsulated potted styles are covered in this manual. The most frequent attention given to power transformers is visual inspection, which involves mainly checking the transformer s general exterior condition and cooling system. Prolonged overload operation will measurably shorten the projected service life of a mineral oilfilled transformer. If the transformer is to be placed near combustible.
Operation and maintenance of drytype general purpose distribution and power transformers and for electrical codes. The information contained herein is intended to be general in nature and therefore may not cover all equipment. The course is a fundamental course covering basic transformers theory, applications, construction, maintenance, and testing. Tfe power transformers operation, maintenance and testing.
In systems in which will be difficult to stop the operation of the transformer for cleaning, or in zones where there are many damages by the dust or the salt, it is being using recently. Installation, operation, and maintenance guide low voltage transformers. References appendix a contains a list of references used. Tm 5686 power transformer maintenance and acceptance. A power transformer requires various routine maintenance.
The degree of maintenance and necessary inspection for its operation depends on. These instructions set out the limiting factors for satisfactory performance of the transformers. Loading considerations when paralleling transformers. Distribution transformers are normally considered to be those transformers which provide the transformation from 11 kv and lower voltages down to the level of the final distribution network.
Installation, operation and maintenance of transformers should be performed by authorized personnel, trained and qualified in the installation, repair and maintenance of electrical equipment. Transformers should be operated only at the ratings specified on the transformer nameplate. Also, the troublefree service of the equipment over its life depends on proper installation, operation, and maintenance. Pdf operation, maintenance and condition monitoring practices. Distribution transformers maintenance guide for liquid. Oil in transformer check for dielectric strength and water content take suitable action to restore quality of oil. The transformer requires less care compared with other electrical equipment. Pdf a procedure for diagnosis and condition based maintenance.
New approaches for transformer operation and maintenance. Historical background, longdistance power in 1886, george westinghouse built the first longdistance alternatingcurrent electric lighting system in great barrington, ma. Power transformers and safety how to install, operate and work with high voltage power transformers safely earthing of hv transformers transformer theory electrical values and their definition in a power transformer voltage, current, number of turns, impedance and their interrelation operation of power transformers in a power system. Bahrain training in stitute corporate training centre po box 33090 tel. Transformer installation, operation, and maintenance manual. The proper operation of the transformer and all its components are verified. Distribution transformers tend to operate at poor load factors.
Thus, when a transformer stepsup a voltage, it stepsdown the current and viceversa, so that the output power is always at the same value as the input power. Dielectric strength filter or replace if bdv is less than specified value. Substation transformer installation, operation, and maintenance instructions and parts replacement information. There are two main types of maintenance of transformer.
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