Abb instrument transformers current transformer theory technical level training course 201203. A current transformer is ideally a shortcircuited transformer where the secondary ter minal voltage is zero and the magnetizing current is negligible. Tpu current trans formers are suitable for the current air insulated. Instrument transformer in power system, the currents and voltages are very large therefore, their direct measurements are not possible. Instrument transformers mitsubishi electric corporation. Instrument transformers for indoor applications product. Instrument transformer basic technical information and. Instrument transformers will transmit the signal to the metering and protective relaying instrumentation, with the purpose of protection of important equipment. The name instrument transformer is a general classification applied to current and.
Instrument transformers will operate successfully under many atmospheric conditions and transients, and switching overvoltages. Instrument transformers are high accuracy class electrical devices used to isolate or transform. Instrument transformers are specific transformer types used for measurement of voltages and. Instrument transformers application guide abb group.
Medium voltage instrument transformers ritz instrument. A current transformer is designed to convert the primary rated current which flows through the primary winding. Instrument transformers are the most common and economic way to detect a disturbance. 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. Instrument transformers application guide installations with abb outdoor instrument. Typical output levels of instrument transformers are 15 amperes and 115120 volts for cts and vts, respectively. A current transformer ct is a type of transformer that is used to reduce or multiply an. Indoor instrument transformers schneider electric belgie. Install the ct as specified in the installation manual supplied. Pdf abb instrument transformers current transformer. Oilinsulated current transformer are used to convert high transmission line currents up to 5000 a. Basics, maintenance, and diagnostics vii contents continued page 4. Voltage transformers are in most situations connected between phase and ground. The turn ratio of the given instrument transformer is 1.
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