The large alternating currents which can not be sensed or passed through normal ammeters and current coils of watt. The current transformer can be used in commercial grade applications such as control panels and panelboards, and for most industrial metering and relay applications in switchboards, switchgear, and motor control centers. Available for voltage system up to 36 kv, single or double pole for vt, and block or ring for ct. Ct analyzer the number one in current transformer testing. Instrument transformers convert signal levels from dangerous high voltage or inconvenient high current, or current at high voltage to levels appropriate for metering. He is also the author of the relay testing handbook series and founder of valence electrical training services. Trench power voltage transformers are the ideal solution for various applications, combining the economy of an inductive voltage transformer and the versatility of a small power transformer, with the safety and reliability features expected from trench products. Potential transformer pt definition the potential transformer may be defined as an instrument transformer used for the transformation of voltage from a higher value to the lower value. Current, voltage and combined transformers, oilpaper or. Such specially constructed transformers with accurate turns ratio are called as instrument transformers. Efficient current transformer testing with omicron ct analyzer. The voltage transformer is designed to connect in parallel with the line to transform the line voltage to 115 or 120 volts suitable for the meter or relay.
Eaton s 5a solid core current transformer is ideal for new construction and retrofit applications where no current transformer exists. Electra cloud is an industrial strength electrical cad software that works fully on the browser with builtin collaboration that allows you to access cad resources everywhere. Testing a form 9s transformer rated installation learn metering. Portable ct pt analyzertransformer testgfuve electronics. Itec cto current transformers utilize high permeability, grain oriented silicon steel cores designed to optimize the performance and physical size of the transformer. Home download center electrical engineering books and technical guides electrical engineering guides current transformers selection guide electrical characteristics primary circuits the primary circuits of the current transformer must withstand the constraints related to the medium voltage network to which it is connected. It might appear that the extension of range could be conveniently done by the use of shunts for currents and multiplier for voltage measurement, as in. The original magnitude can be determined by just multiplying the result with the transformation ratio. You will check the meter, the wiring, the cts andor pts, and the voltage as well as the transformer. Current transformers ct s provide a simple, inexpensive and yet accurate means of sensing current flow in power conductors. You can also use our live chat tool to speak directly with a sales representative. Ironcore transformers are usually used when the source frequency is low below 20 khz.
Nov 25, 2016 can the form 9s be used to meter other services. Transformers transformers on the electrical grid lets look at the electricity that comes to your home. Ct analyzer current transformer testing, calibration and. Large type 2 minature bar ct s minature window ct s minature window ct s pad mount transformers relay class transformers voltage transformers. Basic understanding on current transformer free download as powerpoint presentation. Adopt lcd, selfequipped mini type printer supporting field printing. It acts as a passive load and draws little current, thus preventing inaccuracies in the measurement of the ct. Amran instrument transformers is a leading manufacturer of low voltage and medium voltage instrument transformers current and voltage transformers with multiple manufacturing plants in usa and india.
Large type 2 minature bar cts minature window cts minature window cts pad mount transformers relay class. Ct s current transformers pt s potential transformers 5 potential transformers pt s pt s step down high voltages to the voltage needed by the meter usually 120v occasionally 67v. When the circuit burden gets too large, the ct secondary voltage becomes distorted. Current transformers cts are instrument transformers that are used to supply a reduced value of current to meters, protective relays, and other instruments. Allentown, pa abstract more and more substations are retrofitted with numerical relays, meters and monitoring devices. Instrument transformers convert the currents and voltages of the h. Current transformers ct are used in high voltage hv and medium voltage mv 1 installations to give an image of electrical current to protection relays and units and metering equipment and they are designed to provide a current in its secondary proportional to the current flowing in its primary. When electricity moves from a power plant it is put into a very high voltage to be able to travel long distances. Kami adalah perusahaan pertama dan terbesar di indonesia yang memproduksi trafo distribusi dan perangkat terkaitnya. The test items mainly include excitation characteristic, transformation. The transformer tanks and expansion chambers are manufactured from mild.
Ct2 have an internal termination resistor that reduces re. Pdf improved simulation models for current and voltage. 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. Power voltage transformers station service transformers. To confirm the physical condition and electrical characteristics of current transformer installed in the installation. Tech electrical, iii year, v semester k72 submitted to mr. Pdf improved models for current transformers ct, potential transformers, and capacitive voltage transformers cvt for. Abb library is a web tool for searching for documents related to abb products and services. Basics of ct and pt free download as powerpoint presentation. These instruments transformers are of two types i current transformers ct and ii potential transformers pt. The typical requirement of a protection device for ct dimensioning is for example. Radian research, inc model 505 utec transformer analyzer. It is mainly used for field testing of p class ct and pt.
Current transformer metering ct metering specifications. Ring core ct s are available for measuring currents from 50 to 5000 amps, with windows power conductor opening size from 1 to 8. 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 meter or relay. Current transformer protection units under normal working or fault conditions, with the burden connected, the varistor is subjected to an applied voltage. Instrument transformer in power system, the currents and voltages are very large therefore, their direct measurements are not possible. The high voltage lines can be as high 155,000 to 765,000 volts to travel many hundreds of miles. Arteche offers a wide range that covers all our customers needs. Design and dimensions based on proven trench inductive voltage transformers svs, field experience since 1978 and trench test transformers tes, field experience since 1975 compact size and weight as compared to conventional power. Ct is used for current measurement and pt is used for voltage measurement. The trench group has a full portfolio of instrument transformers that is capable to meet any customers needs worldwide and can be installed in any environmental condition. A general overview of abbs current and voltage transformers. Transformers used for voltage potential measurement. It might appear that the extension of range could be conveniently done by the use of shunts for currents and multiplier for voltage measurement, as in dc.
These transformers are found occasionally in industrial wiring. To check pricing and availability for a specific potential transformer model, give us a call at 614 8896152 or use our quote request form. The transformer is a electrostatic device which is used to transfer electrical energy voltage or current from one circuit to another by mutual induction of two electric circuits without change in frequency, which is working under the principle of electromagnetic induction. The model 505 transformer analyzer is designed for testing current transformers ct and potential transformers pt without interruption of the customers service. Ensure the ct is connected to system properly in all respect primary and secondary. Figure 141 0 two basic types of transformers are the in sulating transformer and the autotransformer. How to select a current transformer the steps to select a transformer from our catalogue are as follows. Clean air, oil or sf6insulated, composite insulator. Abaout ttt eocneccbivbycosnabcyaecntecagcnl mr transformers are used to accurately measure high alternating primary currents, converting the primary current into a. What is the abbreviation for current transformers, potential transformers.
Most often, the older relay gets replaced with a newer relay with the rest of the installation such as current transformer ct and lead. Cts current transformers pts potential transformers. Wound primary ct s are designed to measure currents from 1 amp to 100 amps. Basics of ct and pt transformer physical quantities scribd. Basic understanding on current transformer transformer. Instrument transformer theory and testing steve hudson, pe. Presentation on current transformers submitted by roopal pancholi b. Mar 10, 2016 to start with, both are instrument transformers basically used for measurement and protection purpose in power systems. What is the working principle of a current transformer. Ct pt abbreviation stands for current transformers, potential transformers. It includes current transformers, voltage transformers and combis in oil, gas and clean air insulation as well as special instrument transformers e. The primary windings of the potential transformer are directly connected to the power circuit whose voltage is to be measured. Since the load current passes through primary windings in the ct, screw terminals are provided for the load and secondary conductors.
It transform high primary side current to low current. When testing a form 9s transformer rated installation you will be looking at a few different things. Below is a list of all potential transformers available through flexcore, however, not all models are instock. Available for voltage system up to 36 kv, single or double pole for vt. Output power up to 125 kva in single phase operation. The guiding system, the new way to create your electrical installations a comprehensive offer of products with consistent design. A softironcore transformer is very useful where the transformer must be physically small, yet efficient. There are four typical types of current transformers. This transformer step down the voltage to a safe limit value which can be easily measured by the ordinary low voltage instrument like a voltmeter, wattmeter and watthour meters, etc.
This instrument measures ct admittance, ct ratio, ct primarytosecondary phase angle and the voltage, current and phase angle of the service. Dec 18, 2017 ct is used for current measurement and pt is used for voltage measurement. It transform high voltage of primary side to low voltage. Ts transformers reserves the right to change the specification and the dimensions of the goods. Scribd is the worlds largest social reading and publishing site. The potential transformer is mainly classified into two types, i. Potential transformer testing ptvt valence electrical.
Current transformer, potential transformer working instrument. A current transformer ct is a type of transformer that is used to measure ac current. Cts provide isolation from the high voltage primary, permit grounding of the secondary for safety, and step down the magnitude of the measured current to a value that can be. Instrument transformers are high accuracy class electrical devices used. Back to the basics potential transformer testing ptvt as test equipment becomes more sophisticated with better features and accuracy, we risk turning our field personnel into test set operators instead of skilled field service technicians. The electrical instruments are not directly connected to the meters or control.
Eatons bline series current transformer metering product line includes ct rated meter sockets, ct enclosures, ct mounting bases, combination ct enclosure meter sockets, test switches and transockets that are designed to meet customers needs in a variety of applications, and are suited for many utility specifications. Pt also called voltage transformers vt are a parallel connected type of instrument transformer. Current transformer protection opencircuit conditions. Instrument transformer basic technical information and. Gf106 ctpt tester is mainly used for field testing, it can finish the measurements m and protection p class ct, pt and typ class ct. Basics, maintenance, and diagnostics vii contents continued page 4.
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