power systems loss

VOLTAGE TRANSFORMERS ROUTINE TEST PROCEDURE C57.13.5 Test procedures for voltage transformers. Applied voltage test on the neutral terminal With the ground link temporarily removed from the neutral terminal of the transformer, a voltage of 19 kV (r.m.s.) shall be applied between the neutral terminal and the ground for 60 s. The gas pressure of the gas-filled transformer may be at any setting equal to or less than the pressure given in Clause 5 for the test. The transformer shall be considered as having met the requirements if no external and internal disruptive discharge or collapse of voltage is observed. Accuracy test The test shall be performed in accordance with 8.1 of IEEE Std C57.13-1993. The calibration of the test system given in 4.3 shall apply. The gas pressure of the gas-filled transformer may be at any setting for the test. The transformer shall be considered as having met the requirements if the performance is within the limits of the accuracy class. Exci...

CURRENT TRANSFORMERS ROUTINE TEST PROCEDURE C57.13.5 Test procedures for current transformers. Inter-turn overvoltage test The test shall be performed in accordance with one of the following procedures. If there is no agreement between the manufacturer and user, the choice of the procedure shall be left to the manufacturer. If secondary protective devices are provided, these devices shall be installed for the inter-turn overvoltage test. Procedure A With the secondary windings open-circuited (or connected to a high impedance device which reads the peak voltage), a substantially sinusoidal current shall be applied to the primary winding. The test current shall be increased until one of the following conditions is reached:    a) The r.m.s. value of the applied current is equal to the maximum primary current corresponding to the continuous thermal current rating factor (RF), or    b) The peak value of the secondary induced voltage is equal to:    ...

BASIC INSTRUMENT TRANSFORMER INFORMATIONS AND DISCUSSIONS TAKEN FROM STANDARD HANDBOOK FOR ELECTRICAL ENGINEERS How does instrument transformers being use in the power system? The discussion that follows is a short summary of information on instrument transformers as measurement elements. For more extensive information, consult American National Standard C57.13, Requirement for Instrument Transformers; American National Standards Institute; American National Standard C12, Code for Electricity Metering; Electrical Meterman’s Handbook, Edison Electric Institute; manufacturer’s literature; and textbooks on electrical measurements. AC range extension beyond the reasonable capability of indicating instruments is accomplished with instrument transformers, since the use of heavy-current shunts and high-voltage multipliers would be prohibitive both in cost and power consumption. Instrument transformers are also used to isolate instruments from power lines and to permit instrument circuits t...

69KV CURRENT TRANSFORMER SAMPLE TECHNICAL SPECIFICATION Sample specification of a 69kv Current Transformer. Description: For Oil-Filled Type: The unit shall be hermetically sealed and of the minimum oil-filed type and compact design. All sealing shall be located below the oil level. The expansion room shall be of a gas cushion type filled with nitrogen. Oil level should be of the reflection type and without moving parts. Primary terminals shall be suitable for connection of copper or aluminum connectors. The external ferrous parts shall be of hair pin type insulation consisting of oil-impregnated paper and capacitor layers for voltage grading. It should be preferably provided with a capacitance voltage tap throughout thru an insulated, factory grounded, bushing for checking the condition of its primary insulation. It should have a high seismic withstand capability of 0.5G. The unit must be able to be tilted to 60 deg. C. For Gas Type: The primary and secondary winding of the SF6 ...

69KV VOLTAGE TRANSFORMER SAMPLE TECHNICAL SPECIFICATION Sample specification of a 69kv Voltage Transformer. Description: The unit should be magnetic type and for connection between phase and earth in networks with isolated or earthed neutral. • Designed with low flux density in the core and can therefore be operated at 190% rated voltage for more than 8 hours • Fitted with a secondary measuring winding and a tertiary earth-fault winding • Hermetically sealed, which means no need for regular maintenance procedures • Primary terminals shall be suitable for connection of copper or aluminum connectors. • All external parts are hot-dip galvanized • High seismic withstand capability (0.5G) For Oil-Filled Type: The unit shall be hermetically sealed and of the minimum oil-filed type and compact design. All sealing shall be located below the oil level. The expansion room shall be of a gas cushion type filled with nitrogen. Oil level should be of the refle...

Guide for instrument transformer standard referring to IEEE standards. Scope of the Standard This standard is intended for use as a basis for performance, interchangability, and safety of equipment covered, and to assist in the proper selection of such equipment. This standard covers certain electrical, dimensional, and mechanical characteristics, and takes into consideration certain safety features of current and inductively coupled voltage transformers of types generally used in the measurement of electricity and the control of equipment associated with the generation, transmission, and distribution of alternating current.

How Instrument transformer contributes to system losses? Like any other transformer in general, Instrument transformers are intended to convert current or voltage from the high level in the transmission and distribution systems to the low levels that can be used by low voltage metering devices. Three primary applications for which instrument transformers are usually known: metering (for energy billing and revenue purposes); protection control (for system protection and protective relaying function); and load survey (for economic management of industrial loads).

TRANSFORMER HANDBOOK: ABB This Transformer Handbook prepared by ABB contains a wide range of power and distribution transformers that aims to serve as a guide in understanding, selection, ordering, operation and maintenance of this transformers. The construction of this devices follows standards to the likings of the customers including but not limited to IEC, CENELEC, and ANSI/IEEE. This Handbook although focuses on ABB products, does not significantly differs to the common practice in specifying transformers and ABB based this handbook on their knowledge and experience. Listed below are the main topics that were discussed in this handbook: Every point found in the list are carefully considered. Also, a portion of this handbook tackles all the available standards that are relevant to transformer information. Transformer Types and their Application Quality, Internal Control, Sustainability Loss Capitalization and Optimum Transformer Design Information Required with Enquiry and...

POWER TRANSFORMER SPECIFICATION ISSUES: GUIDE This presentation was originally made by the Electric Power Engineering Centre (EPECentre) at the University of Canterbury in Christchurch, New Zealand. The information found in this document is based on a power transformer specification workshop held in July 2007. The EPECentre takes no responsibility for damages or other liability whatsoever from the use of this document. This includes any consequential damages resulting from interpretation of material. A detailed technical specification of a power transformer is an effective tool in keeping the relationship between a manufacturer and the buyer in harmony. On the Buyer's perspective, having a comprehensive specification for his desired power transformer will  create an effective communication to the manufacturer on what he wants the contractor to deliver. Likewise, from a manufacturer'sperspective, through a clear power transformer technical specification, h...