Product features 600 volt, indoor or outdoor 10 kv bil, 25 60 hertz available with window or primary bar application. In case of bus ct, there must be always connected ct shielding to the primary bar. The new eq meter series complete abb offer of measurement. To start with, both are instrument transformers basically used for measurement and protection purpose in power systems.
Polarity refers to the instantaneous direction of the primary current with respect to the secondary current and is determined by the way the transformer leads are brought out of the case. Maximum allowed torques for screw connections of current transformers maximum allowed torque for screw connection of voltage transformer is 20 nm. Chapter 16 current transformer design university of north. Current transformers technical datasheet schneider electric is the global specialist in energy management with the most complete power. There are four typical types of current transformers. Like the power transformer, the current transformer also contains a primary and a secondary winding. If the transformer happens to have some residual flux in its core at the moment of energisation, the inrush could even be more severe as shown in figure 1. Instrument transformers cmf indoor or outdoor current transformer the cmf current transformer is primarily used with watthour meters, with or without thermal demand attachments. Abbs accurange current transformer portfolio offers low and medium voltage high accuracy, extended range transformers for secondary and primary revenue metering applications. Whenever an alternating current flows through the primary winding, alternating magnetic flux is produced, which then induces alternating current in the. December 2019 type rlc current transformer 600 volt, 10 kv bil, indoor or outdoor.
The cs11 is recommended for measurements that do not require high accuracy, such as. The current transformer will operate into either a short circuit or a resistive load until the voltage induced is enough to. July 2019 type cmvs highaccuracy current transformer accurange leaflet. Abb library ansi outdoor current transformer metering. The basics of current transformers nk technologies. Instrument transformers application guide abb group. Two abb central inverters are used in the abb megawatt station. Transformer protection and control 1mrs756788 a ret630 product version. Introduction the cs11 detects and measures the current along an ac wire using the magnetic field that is generated by that current. A current transformer is defined as as an instrument transformer in which the secondary current is substantially proportional to the primary current under normal conditions of operation and differs in phase from it by an angle which is approximately zero for an appropriate direction of the connections. Utilities can collect additional revenue without having to increase rates per kilowatt hours simply by improving the range and accuracy of metering. The current transformer is designed to connect in series with the line to transform the line current to the standard 5 amperes suitable for the. Instrument transformer basic technical information and.
You can also choose from three, single abb current transformer there are 32 suppliers who sells abb current transformer on, mainly located in asia. The current transformer function is different than that of a voltage transformer. Values mentioned on the rating plate must not be exceeded. Transformer inrush current detector 1manjula b k, 2charan reddy n, 2raju s shivaraj. Nov 15, 2019 the basic principle of the current transformer is the same as that of the power transformer. Abb switchboards offers options for group mounted, generator connection, individually mounted, and metering. Primary terminals of the current transformer are made of. Abb switchboard products are evolution, prostock, spectra series switchboards, av3, and gen tower, individually mounted mains ties and feeders. Ensure the ct is connected to system properly in all respect primary and secondary. Current transformer basics and the current transformer. Current and voltage instrument transformers instruction for. The strategic role of electrification is growing, with urbanization and the world forging ahead to create a lowercarbon future, which abb is supporting with digitally. Abbs electrification business has always been at the forefront of innovative electrification and today is writing the future of safe, smart and sustainable electrification.
This allows them to be used in combination with measurement equipment. One of the voltage inputs can another set of phase current transformers. Technical level training course 201203 abb instrument transformers current transformer theory current transformers why instrument transformers. A current transformer ct basically has a primary coil of one or more turns of heavy crosssectional area. The primary winding can consist merely of the primary current conductor passing once through an aperture in the current transformer core window or bartype, or it may consist of two or more turns wound on the core together with the secondary winding wound type. Current transformer accuracy is specified by the standards ieee std c57. Current transformer white paper the basics of current transformers ratio the ct ratio is the ratio of primary current input to secondary current output at full load. To confirm the physical condition and electrical characteristics of current transformer installed in the installation. Method 1 substation with a single transformer when the plant foresees installation of an. The basic principle of the current transformer is the same as that of the power transformer. The current transformer is mainly used for relay protective scheme because it reduces the high magnitude of primary current to the suitable value for relay operation.
A current transformer is ideally a shortcircuited transformer where the secondary ter minal voltage is zero and the magnetizing current is negligible. Pdf abb instrument transformers current transformer. Instrument transformers current transformer ratio 500. Current transformers reduce high voltage currents to a much lower value and provide a convenient way of safely monitoring the. December 2019 type rlc current transformer 600 volt, 10 kv bil, indoor. Allentown, pa abstract more and more substations are retrofitted with numerical relays, meters and monitoring devices. Abb instrument transformers current transformer theory technical level training course 201203.
Jose carlos mendes transmission and power products technology mng development and engineering mng corporative executive engineer abb asea brown boveri power products division power transformers sao paulo, sp brazil email. The ip5 a ratio current transformer delivers at the secondary a current is of 0 to 5 a that is proportional to the current measured at the primary ip. What is the working principle of a current transformer. On subtractive polarity transformers the h1 primary lead and the x1 secondary lead will be on the same. Tg is a gasinsulated high voltage current transformer based on a topcore. Tg is a gasinsulated high voltage current transformer based on a topcore design, able to withstand current up to 4,000 a and designed for voltages from 72. Current transformer circuit symbols according to ieee and iec standards.
Current transformers, inductive voltage transformers, capacitive voltage. Current transformer ct construction and working principle. The classification of protection current transformers follows the following. This is connected in series with the line carrying high current.
Cmf indoor or outdoor current transformer abb group. The current transformer type cn14c without primary conductor, installation in sf6 gis, indoor or outdoor. A current transformer operates with a set primary current and will try to output a constant current to the load, independent of the load. Abb library is a web tool for searching for documents related to abb products and services. Pdf abb instrument transformers current transformer theory. The sensor outputs a millivolt signal allowing it to be directly connected to our data loggers. Most often, the older relay gets replaced with a newer relay with the rest of the installation such as current transformer ct and lead. Medium voltage distribution components 3022 nc 43 north pinetops, nc, instrument transformers type sch indoor current transformer product features a a 600 volt indoor, 10 kv bil a a 60 hertz a a primary amperes. Current transformers cts have long been a vital component in high voltage transmission and distribution networks. Protection function 6122015 slide 3 abb group detect faults isolate faults selectively and quickly from the network to limit consequences, i. Abb brazil jcm a2 power products division power transformers content introduction shortcircuit in power transformers overview fault types and severity reliability and failure rates international standards shortcircuit performance thermal and mechanical capabilities shortcircuit current characterization and dynamic effect shortcircuit forces, failure modes, tap changers position, aging effects.
Primary and secondary windings are located inside the upper part of the transformer. January 2019 abb instrument transformer and sensor type designations. Today there is a new generation of nonconventional cts ncits that overcome many of the shortcomings of traditional designs. A general overview of abb s current and voltage transformers.
Apr 16, 2011 current transformers principle of operation of ct. Equivalent current transformer circuit x 1 primary leakage reactance r 1 primary winding resistance x 2 secondary leakage reactance z 0 magnetizing impedance r 2 secondary winding resistance z b secondary load note. Abb library is a web tool for searching for documents related to abb products and. Competitive prices from the leading abb current transformers distributor. Low voltage current transformers cannot be used as support elements for current busbars they cannot replace support insulators. Current and voltage potential instrument transformers. Abb complete and comprehensive range of ct current trans formers is the perfect solution for indirect measurement of the electrical parameters that characterize. Abb s accurange current transformer portfolio offers low and medium voltage high accuracy, extended range transformers for secondary and primary revenue metering applications. If a ct test switch is used, the switch must have a makebeforebreak contact pattern to. A wide variety of abb current transformer options are available to you, such as current, power. Design of new transformer protection device based on wavelet energy entropyneural network theory and fpga. In some, the bar carrying high current may act as a primary.
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