It does so in a predictable and proportionate way, allowing for the accurate. Instrument transformers scale the large values of voltage or current to small. Single and multiratio current transformers can be tested. Current transformer metering ct metering overview b. This allows them to be used in combination with measurement equipment. It produces a current in its secondary which is proportional to the current in its primary. Abb library ansi indoor current transformer metering protection 0.
There are four main types of instrument current transformers. Abb library ansi indoor current transformer metering. Because you cant directly read the current, you need a current transformer to read and measure the current for you. The transformer tanks and expansion chambers are manufactured from mild. Instrument transformers application guide abb group. Abb library ansi indoor current transformer meteringprotection 0.
With respect to ansi cts, some of the major details that one would look for in the ct are. This site is like a library, use search box in the widget to get ebook that you want. 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. American national standard for instrument transformers for revenue metering 10kv bil through 350 kv bil 0. Utilitycurrent transformer metering utility enclosures 7 utilitycurrent t ransformer metering type 3r construction 28h x 28w x 11d door hinged on right with padlock provision at left 352 only hinged, utility sealable meter windows. Ct analyzer current transformer testing, calibration and assessment omicron. Abb library is a web tool for searching for documents related to abb. Utilitycurrent transformer metering cooper industries.
Ansi outdoor current transformer meteringprotection 1525kv konhcep ansi outdoor current transformer meteringprotection 1536kv kotd ansi outdoor. If a current transformer is fitted the wrong way round the meter will incorrectly interpret its output as indicating a consuming circuit as generating and viceversa. The magnetooptic current transformer moct is a passive optical current transducer which uses light to accurately measure current on high voltage systems. Instrument transformers convert signal levels from dangerous high voltage or inconvenient high current, or current at high voltage to levels appropriate for metering. On subtractive polarity transformers the h1 primary lead and the x1 secondary lead will be on the same. American national standard for instrument transformers for. The new current transformer and metering speci cations like the iec618692 table above now require accuracies from 0. They are designed and tested to meet the ansi and iec requirements including all the accuracy tests and effects of external influences. April 2019 type kor11e extended range metering current transformer hcep.
Current transformers reduce high voltage currents to a much lower value and provide a convenient way of safely monitoring the. National electrical manufacturers association approved november 6, 2007 american national standards institute, inc. Abb library is a web tool for searching for documents related to abb products and. Oct 05, 2016 metering current transformers are designed to be within quite accurate values up to say two x rated current, and down to metering current transformer will get a heavily saturated waveform during fault conditions and it wont work properly. That means, in first current transformer, the metering core would be saturated at 1. The present disclosure describes a system for monitoring energy data having at least one wireless current transformer, a metering circuit configured to receive an analog signal from the current transformer and to calculate energy data, a wireless transmitter unit in circuit with the metering circuit which is configured to transmit the energy data, and a receiver unit having a receiver, a. What is the difference between metering and protection ct. A metering transformer, also known as an instrument transformer, can be used where the circuit current is too high to deploy measuring or metering instruments directly. The current transformer must have its secondary terminals short circuited or the burden connected before energizing the primary circuit. To provide possibilities of standardizing the instruments and relays to a few rated currents. The metering transformer reduces the current to a level that those instruments can safely handle. Queensland electricity metering manual check this is the latest version before use. In practice, it becomes necessary for timetotime, to remove such transformers for.
The model 456 potential transformer provides utility grade accuracy at 0. December 2019 type rlc current transformer 600 volt, 10 kv bil, indoor or outdoor. Current sensing for energy metering analog devices. This protects connected metering devices from overloading in the presence of fault level current flows. Hv instrument transformers comprehensive range up to 1,200 kv including current transformers, magnetic voltage transformers, combined metering units, capacitor voltage transformer, gis voltage transformers and power voltage transformers.
High accuracy, extended range current transformers for more accurate revenue metering. Abb library ansi outdoor current transformer metering. Calculation of cts if the current transformer has primary to secondary current ratio of 100. In some, the bar carrying high current may act as a primary. Eaton s 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. Tape wound measuring and protection current transformers. Metsect5da040 current transformer tropicalised 400 5. The moct system is suitable for outdoor application and has an accurate metering current range from less than 5 a to 3150 a using the same sensor. Current transformer basics and the current transformer. To insulate the metering circuit from the primary high voltage system. The form 9s meter is perhaps one of the most popular meter forms used in metering. The 3in1 current transformer range are for use with the integra dl1 digital metering. Energy metering using potential and current transformers. Meder current transformers play a key role in this smart metering process.
Polarity must be observed when fitting current transformers. Ex manual 01812 ver 2 ee na000403r510 ver 2 joint document between energex and ergon energy. Suppose one current transformer has rating 1001 a and isf is 1. Ansi metering current transformer burden e l t e l s c r o l l j u n e tel. 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. It does so in a predictable and proportionate way, allowing for the accurate measurement of the total current to be deduced from. Current transformer circuit symbols according to ieee and iec standards. Us2756399a mounting for metering current transformers.
Handbook for electricity metering download ebook pdf, epub. Utilitycurrent transformer metering platt electric supply. Current in the monitored circuit produces a reduced but proportional current in the standexmeder current transformer which is then monitored by measuring instrumenta. Typical applications include energy management, relays, ameters, voltmeters, and wattmeters. Closed core type current transformer current transformers current transformers have two basic functions. Current transformer ct construction and working principle. Metsect5da040 current transformer tropicalised 400 5 double output for bars 32x65.
Pdf method of current transformer metrological properties. Abb library is a web tool for searching for documents. Bolts 2628 not only provide means for attaching bus bars 12 to the legs 18 of support 10, but also permit alternate insertion of primary conductor 14 and shorting bar 38 in the particular connection. It is not always satisfactory for revenue and precision metering. December 2019 scl and scld current transformers 600 volt. The ct analyzer is a test system for protection and metering cts according to ieee and iec standards. See pages 121 through 124 for service center locations. 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. The name instrument transformer is a general classification applied. Testing a form 9s transformer rated installation learn metering. Abb library is a web tool for searching for documents related to abb products and services.
Providing accurate measurement of the energy consumption of commercial buildings, industrial plants and residential housing is the basis for billing by utility companies. Click download or read online button to get handbook for electricity metering book now. Recently, we have also shown that by using a lowimpedance excitation transformer and manual compensation, it is possible to keep 0. Make sure the total burden does not exceed the specified limits for the ct. The present disclosure describes a system for monitoring energy data having at least one wireless current transformer, a metering circuit configured to receive an analog signal from the current transformer and to calculate energy data, a wireless transmitter unit in circuit with the metering circuit. Itec cto current transformers utilize high permeability, grain oriented silicon steel cores designed to optimize the performance and physical size of the transformer. Cts for watthour meters falco specializes in developing current transformers for electricity meters according to specific needs in terms of accuracy, mechanical constraints. Solidstate electric energy meters contain both voltage and current sensing elements.
Standard accuracy class for metering service and corresponding. Cts current transformers pts potential transformers. Energy metering using potential and current transformers energy metering is one of the critical functionalities of todays metering devices. This is connected in series with the line carrying high current. The latest current transformers make it possible to measure high current values and indicate these using instruments of a much lower rating. Oct 08, 2016 calculation of cts if the current transformer has primary to secondary current ratio of 100. Electric currents in the circuit are too high to be applied directly to measuring instruments. The correct way to specify and install current transformers. Moct optical current transformer system for metering 72. A current transformer ct is a type of transformer that is used to reduce or multiply an alternating current ac. Mar 07, 2017 the ct is instrumental in measuring electricity. Current transformer metering ct metering specifications.
The provision of bus bars 12 for each metering connection avoids any rewiring of the primary each timethe current transformer is replaced. The portfolio also includes line traps and digital instrument transformers. A metering ct carries the full load current and are designed near the saturation point. Pdf during transformation of power frequency currents inductive current. Metering current transformers are designed to be within quite accurate values up to say two x rated current, and down to download pdf info publication number.
Mounting base stud locations accepts 6019xx series c. Protection or metering devices have to receive data on electrical values current or voltage from the. A current transformer ct basically has a primary coil of one or more turns of heavy crosssectional area. Ansi metering current transformer burden eltel industries. January 2019 instrument transformer reference meter and relay applications for the electrical industry. Ct analyzer current transformer testing, calibration and. Download handbook for electricity metering or read online books in pdf, epub, tuebl, and mobi format. The classification of protection current transformers follows the following.
Nov 25, 2016 the form 9s meter is perhaps one of the most popular meter forms used in metering. 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. Current transformers, along with voltage or potential transformers, are instrument transformers. Any meter that gets installed will require you to connect directly to voltage and current. Can i use same current transformer for metering and. 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.
Refer to the table at the right to determine the resistance, in ohms or va, of the wires that connect the secondary of the current transformer to the device. If a ct test switch is used, the switch must have a makebeforebreak contact pattern to. Whereas the basic purpose of the protection ct is to provide protection in case of any fault. The basics of current transformers nk technologies. 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. Screws for the busbar fixing are included in delivery. It is a versatile meter that can be used to meter either a 120208 three phase four wire wye service or a 277480 three phase four wire wye service. Handbook for electricity metering download ebook pdf. Owing to high costs in cable we recommend the use of a current transformer for the current measurement above 40a unless otherwise specified.
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