Home products transformer testportable ct pt analyzer. Transformer testing allows this aging process to be quantified and tracked, to help predict replacement intervals and avoid failures. Voltage transformer testing swp page 1 of 19 standard work practice sp0508 ver 7 ergon energy corporation limited abn 50 087 646 062 1. Testing transformer3 easy methods to test transformers. A fault leading to an open secondary could cause the primary current to overwhelm the. Transformer pd and induced voltage withstand test system. The following sections of the ansineta standard for acceptance testing specifications for. Current transformer testing 1 of 6 isaadvancedtesting. Traditional current transformer testing follows a blackbox approach. Drytype transformer testing introduction the primary concern with all transformers and also the key indicator of life expectancy is the condition of the insulation system.
Instrument transformers for metering purposes must have a high degree of accuracy up to class 0. Calculation of winding temperature at the end of temperature rise test of transformer. The test setup and procedure of the frsl test is the same as for shortcircuit impedanceleakage reactance testing and can be performed simultaneously. Testing power transformers test procedures and equipment used for the testing of large power transformers at abb oy, power transformer, vaasa works are dealt with in the following sections. I wrote an article for the neta world magazine in 2004 that covers several different manual techniques for current transformer testing that should help even the most experienced technicians. Instrument transformers cts and pts have wide application in metering and protecting the power system. Power transformer factory test using ieee standards. All the routine tests shall be repeated dielectric test shall be at 75% transformer shall be untanked reactance measured after s. Mainly two types of transformer testing are done at manufacturer premisestype test of transformer and routine test of transformer. The priciples of routine, type and special tests are however. Transformers regulate the voltage in circuits, but in some cases these. When testing a transformer for turns ratio, the connections are determined by matching parallel vectors. There is excess current in the coil, resulting in the winding heating up and getting damaged. This test also performed as a routine test of transformer.
To confirm the physical condition and electrical characteristics of current transformer installed in the installation. So for ensuring proper performance of electrical power transformer, voltage and turn ratio test of transformer one of the important tests. Portable precision current transformer testing ct pt analyzer. The current transformer is solely assessed through its external behavior without considering what is happening inside. Where the test procedure is not specified, the requirements of iec 60076 apply. This application note describes tap changer testing in general and details on how to use the capabilities in mto210, 300 and 330 for tap changer measurements.
May 09, 2016 since there is a ratio of 1 to 4 between the turns in the primary and secondary circuits, there must be a ratio of 1 to 4 between the primary and secondary voltage and a ratio of 4 to 1 between the primary and secondary current. Both paper and oil which are used for insulation in the transformer start getting degenerated and get decomposed. Transformer manufacturers perform two main types of transformer testing type test of transformer and routine. Transformer is the most important equipment in the electrical power transmission and distribution system. During construction, and before, startup, new electrical systems and components must meet application specifications, manufactures tolerances, installation and construction codes and standards, and system design specifications. Scribd is the worlds largest social reading and publishing site. Feb 08, 2015 there are various test required on transformer to conform performance of transformer. Winding resistance test of transformer electrical4u. Modern transformers are designed to closer tolerances than transformers in the past. Transformer testing carried out in accordance with applicable iec and ansi specifications, unless otherwise specified in the contract documents. Oct 11, 2015 oscillogram of dynamic shortcircuit test on 3phase 110. Silsbee contents t page introduction 317 generalprinciples 318 nullmethod 321 deflectionmethod 325 experimentalresults. There are various test required on transformer to conform performance of transformer.
The measuring equipment differens from those explained herein. These properties are used to evaluate the end of reliable life of paper insulation. Nov 10, 2014 basic transformer testing methods before we get into transformer testing, it is important to understand why they need to be tested. Historical test data is valuable for determining damage to the transformer after a fault or failure has occurred elsewhere in the circuit. In order to ensure availability of uninterrupted power supply, it is essential that the condition of transformer is continuously monitored during service as failure of transformer would result in interruption of power supply resulting loss of industrial production. The performance parameters of interest can be obtained by solving that circuit for any load conditions. Type test and routine test of transformer electrical mastar. This includes power factor testing and other standard neta testing requirements. Power transformer testing power transformer factory test using ieee standards waldemar ziomek cg power systems canada ieee training, houston, texas, oct.
Transformer testing commissioning, routine, diagnostic. In order to ensure availability of uninterrupted power supply, it is essential that the condition of transformer is continuously monitored during service as failure of transformer would result in interruption of power supply resulting loss of industrial production and inconvenience to. Transformer field services transformer testing california. For dry type transformers, the insulation system consists of the cast resin winding and core insulation. Transformer testing techniques electrical engineering portal. Gray transformer chemistry services direct evaluation the mechanical properties of insulating paper can be established by direct measurement of its tensile strength or degree of polymerization dp. It evolved from the simple gonogo verdict into a sophisticated segment within transformer manufacturing. Although transformer failure is rare, there are two basic reasons for their failure. In addition some other tests are also carried out by the consumer at site before commissioning and also. The equivalent circuit parameters areavailabletothedesigner ofthetransformers.
Transportation, erection, testing and commissioning. The test items mainly include excitation characteristic, transformation. In this article im only explain on how to test the linear transformer. Transformer testing type tests and routine tests of. Ensure the ct is connected to system properly in all respect primary and secondary. Hence, it is essential to inspect and calibrate those instrument transformers at regular intervals.
The transformer must be deenergized before this procedure, unless it. So transformer ratio test is an essential type test of transformer. Routine tests and type tests of transformers electrical4u. A winding resistance test of a transformer is carried out as a type test, routine test and also as a field test. For confirming the specifications and performances of an electrical power transformer it has to go through numbers of testing procedures. This video explains how to perform tests on ct current transformer with ratio and polarity voltage and current mode. It is mainly used for field testing of p class ct and pt. Transformer turns ratio test sets come in a variety of styles and test connections, however all turns ratio testers have at least two high leads and two low leads. A fault leading to an open secondary could cause the primary current to overwhelm the insulation, causing the winding to short circuit. Magnetization and primary injection test of current. This amounts to a rigorous examination of the transformer intended to. May 10, 20 for confirming the specifications and performances of an electrical power transformer it has to go through a number of testing procedures.
Oscillogram of dynamic shortcircuit test on 3phase 110. In this paper, various intelligence techniques are used to test. Some transformer tests are also carried out at the consumer site before commissioning and also periodically in regular and emergency basis throughout its service life. Nov 26, 2010 traditional current transformer testing follows a blackbox approach.
Comprehensive electrical testing is offered to our customers. Peace of mind are delivered with neta electrical testing that determines the fitness of your new electrical system. Page 1 of 9 standard work practice sp0507 ver 5 ergon energy corporation limited abn 50 087 646 062. As 12431982 voltage transformers for measurement and. The methods used during tests and measurements of the power transformers, test and measurement circuits, calculations and evaluation criterias are included in this manual. This information is required to insure the ct will perform under all circumstances. From the analysis of the equivalent circuit one can determine the electrical parameters. Section 7 of the ansineta standard for acceptance testing specifications for electrical power equipment and systems may be reproduced and used on a cut and paste basis for the particular type of equipment to be tested. Some tests are done at a transformer manufacturer premises before delivering the transformer. Indigenously manufactured transformers have a wide range of ratings.
In manual method, lot of time is required to test any type of transformer and risk involved is higher. Purpose and scope the purpose of this standard work practice swp is to provide guidelines for testing methods for capacitive and inductive voltage transformers. The need for a comprehensive current transformer testing regime is evident when the alternative is considered. Transformer oil and other insulating liquids suffer from electrical and mechanical stresses while a transformer is in operation. Transformers regulate the voltage in circuits, but in some cases these can go bad and cause a circuit to not. Generally there are two types of transformer in the market i. The ctt5 burden test injects a current into the secondary loop to verify the integrity of the current circuit and to determine its impedance and va. Standard for acceptance testing specifications for.
In this book we have laid down important aspects on transformer. The voltage ratio of a transformer is the ratio of the rms terminal voltage of a. Cts are instrument transformers used for converting primary current into a reduced secondary current for use with meters, relays, control equipment and other instruments the importance of instrument transformer tests is often underestimated. It is not replacing the mto user manuals where general operation of the instrument and connection schemes for various transformers is described. Current transformer tester model ctt5 testing applications design features. The procedure of the transformer ratio test is simple. Heres a summary of the current transformer testing paper.
Partial discharge testing can detect the presence and location of partial discharge activity in a transformer. In addition there are contaminations caused due to chemical interactions with windings and other solid insulations, catalyzed by high operating temperature. As voltage is stepped up, the current is stepped down, keeping volts multiplied by amps constant. The insulation of the transformer is the one to get a. Testing transformer is very easy if you follow the procedure explained in this article. All materials and relevant documentation to this testing works shall be checked by the responsible personnel prior to the commencement of testing activities.
Testing of three phase power transformer ijireeice. This test usually known as no load test and involves inserting an alternating voltage in the high voltage winding of the transformer in each of its phases with low. But if the temperature rise of the transformer is required, then test method is. Modeling and testing of ethernet transformers article pdf available in ieee transactions on magnetics 4510. It is equivalent to the procedure used for performing a shortcircuit impedance test on an autotransformer. Testing will commence only after the equipment is completely installed as per approved method statement for the installation of the transformer and released for testing commissioning. A primary part of commissioning a transformer involves testing it after its installation in the field. Portable ct pt analyzertransformer testgfuve electronics. The transformer has been built to standard damage has not been sustained during transit or installation. Testing of power transformers seems like a similar experience. Testing and commissioning instrumenttransformers free download as powerpoint presentation. Partial discharges in transformers are typically measured by applying a prespecified voltage to the transformer windings and measuring induced charges via a coupling device e.
The purchase, preparation, assembly, operation and maintenance of transformers represent a large expense to the power system. Mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. Transformer tests eep electrical engineering portal. In the factory, it helps in determining the following.
This heats the transformer and the temperature of the transformer increases. Some tests are done at manufacturer premises before delivering the transformer. Basics, maintenance, and diagnostics xi contents continued page 9. Current transformer testing swp check this is the latest process zone version before use. Instrument transformer theory and testing steve hudson, pe engineering manager 10737 lexington drive knoxville, tn 37932 phone. How to test a switch mode transformer custom coils blog. Connection on cpc100 will be same as the shown figure. Figure 5 shows the result of the curve fitting for core 1, considering the y axis to be the current and x axis to be the. Testing and diagnostics of power transformers brochure 4. Magnetization and primary injection test of current transformer for protective relaying jacob tsado 8 current transformers. Transformer testing has developed considerably over the past years.
Current transformers play an important role in the monitoring and protection of electrical power systems. Eaton recommends the use of snubber circuits unless the manufacturer can provide full testing documentation as. Before we get into transformer testing, it is important to understand why they need to be tested. Repeat the test for the other phases and the other secondary cores. Transformer manufacturers perform two main types of transformer testing type test of transformer and routine test of transformer. Sep 26, 2017 for confirming the specifications and performances of an electrical power transformer it has to go through numbers of testing procedures. Standard for acceptance testing specifications for electrical. Testing power transformers highvoltage transformers are some of the most important and expensive pieces of equipment required for operating a power system. Transformers are an electrical component that transmit electrical energy between at least two circuits. To understand the nature of ratio testing it is important to understand the applicable definitions.