Telephone: +41 22 02 11 Telefax: +41 22 03 00 E-mail: [email protected] Web: INTERNATIONAL. STANDARD. IEC. Third edition. This part of IEC identifies the requirements for power transformers to sustain without damage the effects of overcurrents originated by external short. IEC. Second edition. This English-language version is As from 1 January all IEC publications are issued with a designation in the.
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This increase in current should be taken into consideration when calculating the temperature rise of the zigzag winding. Enter the exact number of the standard: In order to consider the transformer as having passed the short-circuit test, the following conditions shall be fulfilled: Reference number IEC This applies, for example, to unit generator transformers if the connection between generator and transformer is constructed in such a way that the possibility of line-to-line or double-earth faults in this region is negligible.
Particular requirements and tests for safety isolating transformers and power supply units incorporating safety isolating transformers. With regard to tap-changer position and test sequence, the same procedure as described for transformers of categories I and II is recommended. Safety of power transformers, power supplies, reactors and similar products Part CombiFinder Discover how to find in thousands configurations, the Combination unit for you.
Please contact the Customer Service Centre see below for further information. Table 2 — Short-circuit apparent power of the system Highest voltage for equipment, U m Short-circuit apparent power kV MVA Current European practice 7,2; 12; 17,5 and 24 36 52 and 72,5 and and 1 3 6 10 20 30 35 40 60 83 Current North American practice 1 5 15 15 25 30 35 40 60 83 NOTE If not specified, a value between 1 and 3 should be considered for the ratio of zero-sequence to positive-sequence impedance of the system.
The text of this standard iex based on the following documents: The method is advantageous in preventing any saturation of the core ice will reduce the power requirement of the supply. Safety of power transformers, power supply units and similar Part General requirements and tests IEC Safety of power transformers, power suply units and similar Part 2: NOTE In connection with the economical impact of the cost of a transformer of category III and the cost implication of any thorough visual inspection extended to the inner parts of the unit, it is recommended that a series of photographs be taken of the position of the winding leads, taps, alignment of spacers and configuration of the end insulation components, etc.
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The requirements apply to transformers as defined in the scope of IEC NOTE 2 Any differences between 600076-5 results of measurements made before and after the test may be used as a criterion for determining possible defects. For star-connected windings, the singlephase voltage is supplied between one line terminal and the other two line terminals connected together. By necessity, it is left to the mutual agreement between the parties to accept the existence of small displacements and changes, provided that the service 06076-5 of the transformer is not affected.
Another method for determining the phase current in a delta-connected winding is by suitably interconnecting the secondary windings of the current transformers measuring the line currents. In general, such conditions are of a more complex nature in comparison with the three-phase short circuit which can be considered the reference case for two-winding transformers ic 3. The winding closer to the core is to be short-circuited in order to avoid saturation of the magnetic core which could lead to an excessive magnetizing current superimposed on the short-circuit current during the first 60067-5 cycles.
International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. These procedures and reactance limits are given in the following items a and b.
Q2 Please tell us 600076-5 what capacity ies you bought the standard tick all that apply. In these cases, the testing conditions shall be agreed between the purchaser and the manufacturer.
When calculation and design consideration is selected, validation by comparison with a previously tested similar transformer or tests on representative models is required. External short circuits are not restricted to three-phase short circuits; they include line-to-line, double-earth and line-to-earth faults.
INTERNATIONAL STANDARD IEC 60076-5
Discover how to find in thousands configurations, the Combination unit for you. Protection accessories, such as a gas-and-oil-actuated relay and pressure relief device, shall be mounted on the transformer during the test.
Table of physical and chemical constants — Kay and Laby — 15 edition, Longmans, General requirements for basic safety and essential performance. General requirements and tests. For three-phase tests on delta-connected windings, this condition is obtained by switching on when the line-to-line voltage passes through zero.
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For all transformers, excluding the case given in 3. If the short-circuit apparent power of the system is not specified, the values given in table 2 shall be used.
NOTE It may not be economical to design auxiliary windings to withstand short circuits on their terminals. Please, select your language. Safety of power transformers, power suply units and similar Part 2: For example, edition numbers 1.