Current transformers technical datasheet schneider electric is the global specialist in energy management with the most complete power monitoring product line. Tape wound measuring and protection current transformers. This protects connected metering devices from overloading in the presence of fault level current flows. The x1 secondary terminal is the polarity terminal figure 3.
Jun 01, 2015 introduction generally a transformer is an electrical device or machine which inductively transfers the electrical power operating at a particular current and voltage of one circuit to the other circuit which is operating at different current and voltage level. Bar and donut type cts do not have a physical primary winding and are considered to have one primary turn. Blue sea makes some good products and has a outstanding reputation. The doughnut fits over the primary conductor, which constitutes one primary turn. Most of the transformers are manufactured such that their characteristics must match for special. It should be connected measuring devices before application of primary connection as seen in figure1. I purchased this ac current transformer for a power generator wattage meter and it does a great job measuring the wattage of my generator. Most of the transformers are manufactured such that their characteristics must match for special application requirements. It buffers the meter from experiencing excessive torques that might be. I received the transformer very quickly and it was well package, i highly recommend this product for all your electronic needs. December 2019 type rlc current transformer 600 volt, 10 kv bil, indoor or outdoor. Medium voltage current transformers cable type kola are suitable for the measurement of the sum of threephase currents in a 3phase cable.
Low voltage current transformer low voltage current transformer general reference standards iec600441, vde0414441, din57414, bs3938, bs7626, en600441, gb12082009 measuring current transformers are constructed to feed on other low voltage apparatus such as measuring instruments, relays, watthour meters kw meter and these type of current. A potential transformer is a conventional transformer having primary and secondary windings. Basics, maintenance, and diagnostics vii contents continued page 4. Socomec current transformers deliver a standard current to the secondary that is proportional to the primary. The active elements are located in a hermetic housing inside the head of the transformer. Metering toroidal current transformers traditional, window type current transformers for measuring 50400hz currents of 5a to 15000a with secondaries of 0. Huayi professional current transformer, voltage transformer, capacitor voltage transformer, transformer, surge arrester manufacturers and suppliers in china, providing the best quality transformer made in china with competitive price. To check pricing and availability for a specific current transformer model, give us a call at 614 8896152 or use our quote request form. For a low voltage wound type ct, the secondary turns are wound on a bakelite former and with a. Current transformers ratio polarity types educypedia. Current transformers cts can be used for monitoring current or for transforming primary current into reduced.
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. Abb library is a web tool for searching for documents related to abb products and services. Distribution transformers are step down transformer, which converts high grid voltage to the end customer required voltage, 110v or 230v. To confirm the physical condition and electrical characteristics of current transformer installed in the installation. The core construction of berry type transformer is like spokes of a wheal.
These are the most commonly used transformer types for all the applications. This type of transformers is used in component protection purpose. Bar type cts operate on the same principle of donut cts but have a permanent bar installed as a primary conductor. Current transformer basics and the current transformer. For example, the potential transformer mentioned above having a rating of 480. Current transformers, model 186 current transformer simpson. This type of current transformer is available to measure ac currents from 100a to 600a, at 50 to 400hz.
Abb library is a web tool for searching for documents related to abb products. The polarity marks of a current transformer indicate that when a primary current enters. This type of ct often has compensating windings which improve the accuracy across the full load range of the transformer. Current transformers are essential components designed to be used with schneider electrics extensive power monitoring product portfolio. It is actually a shell type transformer but the name is related to the designer and its cylindrical shape. The polarity marks of a current transformer indicate that when a primary current enters at the polarity mark h1 of the primary, a current in. The primary of the current transformers is directly connected in series with the line conductor that. They are very popular in submetering applications where existing systems are being upgraded and it is impractical to isolate the primary conductor. Here we discuss different types of transformers are the step up and step down transformer, distribution transformer, potential transformer, power transformer, 1. Current transformers type pa 123 kv and 145 kv instrument. Pa current transformers are filled with pcbfree transformer oil.
A current transformer ct is a type of transformer that is used to reduce or multiply an. However, the concept of knee point voltage is very pertinent to protection current transformers, since they are necessarily exposed to currents of 20 or. Types of transformer different types of transformer. The major difference between measuring transformers and protection transformers is the accuracy that means that the protection transformers should be accurate as compared to measuring transformers. These transformers provide insulation against the high voltage of the power circuit, and also supply the relays with quantities proportional to those of the. The transformer is a static electric device consisting essentially of two or more windings wound on the same core electromagnetic induction transforms electric energy from one circuit to another circuit such that the frequency of the energy remains unchanged while the voltage and current usually change definition of a transformers. A current transformer is an instrument transformer, used along with measuring or protective devices, in which the secondary current is proportional to the primary current under normal conditions of operation and differs from it by an angle which is approximately zero. Bartype cts have primary connections that boltup directly to the substation bus bars. Ring type current transformer is constructed of an iron toroid, which forms the magnetic core of the current transformer, and secondary turns are wound with copper wire. Types of electrical transformers and their applications. Whenever an alternating current flows through the primary winding, alternating magnetic flux is produced, which then induces alternating current in the. With 150 amps through the 300 amp rated primary, the secondary current will be 2. Instrument transformer basic technical information and. When the rated primary amps is exceeded, which is usually the case when a fault occurs on the system, the amount of secondary current will increase.
Current transformers, model 186 current transformer. The specific application of current transformers involves in various considerations such as type of mechanical construction, ratio of primary to secondary currents, type of insulation oil or dry type, thermal conditions. When current flows through the primary winding, the following actions occur. This paper describes the saturation study of current transformer during transient fault. If the application requirements are not fully defined, refer to. Nov 15, 2019 the basic principle of the current transformer is the same as that of the power transformer. Ensure the ct is connected to system properly in all respect primary and secondary. Bartype current transformer this type of current transformer uses the actual cable or busbar of the main circuit as the primary winding, which is equivalent to a single turn. A bartype current transformer which has 1 turn on its primary and 160 turns on its secondary is to be used with a standard range of ammeters that have an internal resistance of 0.
The classification of protection current transformers follows the following. Like the power transformer, the current transformer also contains a primary and a secondary winding. Different types of transformers and their applications. Jun 02, 2015 therefore, the current transformer does the current conversion from high currents to a measurable range of currents. The primary of the current transformers is directly connected in series with the line conductor that carries the entire. The ratio of an instrument transformer is the relationship of its primary rating to its secondary rating. Protection current transformers are constructed to feed the protection relay. April 2019 type csh current transformer 600 volt, 10 kv bil, indoor or outdoor. Msq current transformer technical characteristics of current transformers. Indoor current transformer cable kola current transformers type kola indoor dry type, cast resin insulated are designed for rated voltages up to 0. The above image is showing the construction of the current transformer. When current flow exceeds that rating, the metering core will become saturated, thereby limiting the amount of current level within the device.
Window type cts should be mounted with the h1 side of the window towards the power source. Used in ac system for the measurement of current, voltage, power and energy. Wound cts have a primary and secondary winding like a normal transformer. Types kotd110, 150, and 200 current transformers medium voltage instrument transformer nsv 15 kv through 36 kv outdoor primary amperes 4005000 25 through 60 hertz type kotd110110 kv bil. Current transformer market by type dry type current. Instrument transformers are also used with protective relays for protection of power system basic function of instrument transformers is to step down the ac system voltage and. The construction of the current transformer can be wound or bar type.
The name instrument transformer is a general classification applied to current and. Outdoorrated versions of this equipment are used in pole mounted primary metering installations. They are fully insulated from the high operating voltage of the system and are usually bolted to the currentcarrying device. Perfect for low current measurement where a donut current. The current transformer of type lvb110v is oil insulated and outdoor product. Introduction generally a transformer is an electrical device or machine which inductively transfers the electrical power operating at a particular current and voltage of one circuit to the other circuit which is operating at different current and voltage level. Secondary winding of a current transformer must not be operated with an open circuit. Wound type ct is similar to the two winding conventional transformer. This makes the replacement of instrument transformer very easy. It is used for metering electric energy, current and relay protection of 115kv in electric substaion system and frequency is 50hz or 60hz. Ring type current transformer do not contain a primary. Transformer with the primary current be turned twice which help to keep the samerated turns ratio1.
Current transformers 99 protective relays of the ac type are actuated by current and voltage supplied by current and voltage transformers. Determine the usual application of current transformer that best suits the application for which it is intended. It is even possible to install this type of transformer while the conductor is energized. 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. Parts of current transformer like any transformer, a current transformer has a primary winding, a core and a secondary winding, although some transformers, including current transformers, use an air core. You can also use our live chat tool to speak directly with a sales representative. Transformers used for voltage potential measurement steps down the voltage to the level of voltmeter. The basics of current transformers nk technologies. Instrument transformers are used in ac system for measurement of electrical quantities i. They are designed using top core current transformer construction. In thrutype units, busbar and copper tube inside the unit need to be at the same potential.
Back to the basics current testing valence electrical. For the encapsulated type current transformer, the windings are enclosed in a. Current transformers, model 186 current transformer simpson electric optimal for remote sensing of ac current signals. In principle, the only difference between a current transformer and a voltage transformer normal type is that the former is fed with a. Current transformer ct construction and working principle. This type of transformer is categorized on the basis of a number of turns in the primary and secondary windings and the induced emf. Contents hide 1 different types of current transformers. The primary winding consists of more than one full turn or multiple turns which is wounded on the core.
Below is a list of all current transformers available through flexcore, however, not all models are instock. China current transformer, voltage transformer, surge. The various types of transformer shown in the figure above are explained in detail below. Oct 08, 2016 in principle, the only difference between a current transformer and a voltage transformer normal type is that the former is fed with a constant currentwhile the latter is fed with a constant voltage, where constant has the strict circuit theory meaning. The secondary winding of current transformer which will not be used must always be shortcircuited and earthed as seen in figure2. The kneepoint voltage is less applicable for metering current transformers as their accuracy is generally much tighter but constrained within a very small bandwidth of the current transformer rating, typically 1.
Current transformers cts are instrument transformers that are used to supply a. Current transformers reduce high voltage currents to a much lower value and provide a convenient way of safely monitoring the actual electrical current flowing in an ac. For use with rectifier type analog panel meters or digital indicators. Perfect for low current measurement where a donut current transformer would not sense a signal download datasheet. Berry type transformer has more than two independent magnetic circuits i. Type psh993 indooroutdoor current transformer instrument transformers and sensors application the psh993 indooroutdoor, windowtype current transformer is a 600 volt, 10 kv bil rated unit. Another very common type of construction is the socalled window, through or donut type current transformer in which the core has an opening through which the conductor carrying the primary load current is passed. This unit can be applied over higher rated system voltages provided sufficient insulation is available on the point of application. A measurement type ct of 20005 a, 25va rating is used. Typically current transformers consist of a silicon steel ring core wound with many.
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