Table of Contents

Introduction
1 Scope
2 Normative references
3 Definitions
4 Normal service conditions
5 Unusual service conditions
6 Classification by thermal class
7 Ratings
7.1 Classification by rated power
7.2 Rated voltages
7.3 Tapping voltages
7.4 Rated power factor
8 Performances
8.1 No-load current
8.2 No-load loss
8.3 Transformation ratio
8.4 Short-circuit impedance
8.5 Balance of single-phase 3-wire system
8.6 Voltage regulation
8.7 Efficiency
8.8 Limit of temperature rise
8.9 Dielectric strength
8.9.1 Applied potential withstand voltage
8.9.2 Induced withstand voltage
8.9.3 Lightning impulse withstand voltage
8.10 Partial discharge
8.11 Noise
8.12 Ability to withstand short circuit
8.12.1 Thermal ability
8.12.2 Mechanical ability
8.13 Variation in voltage and frequency
8.14 Resistance to cracking
8.15 Resistance to damp heat
8.16 Flame retardance
8.17 Tolerance
9 Construction
9.1 Construction in general
9.2 Tap change-over terminals
9.3 Earth terminal
9.4 Connection of transformer
9.4.1 Single-phase transformer
9.4.2 Three-phase transformer
9.5 Terminal mark, polarity and phase displacement
9.5.1 For single-phase transformer
9.5.2 For three-phase transformer
10 Tests
10.1 General matters relating to routine tests, type
tests and special tests
10.1.1 Routine tests
10.1.2 Type tests
10.1.3 Special tests
10.2 Measurement of winding resistance
10.3 No-load current and no-load loss tests
10.4 Transformation ratio test, polarity test and phase
displacement test
10.5 Load loss and short-circuit impedance tests
10.6 Test for balance of single-phase 3-wire system
10.7 Voltage regulation
10.8 Efficiency
10.9 Temperature rise method
10.9.1 Loading methods
10.9.2 Thermal equilibrium state
10.9.3 Methods for measurement and calculation of
transformer temperature
10.9.4 Determination of reference ambient temperature
10.9.5 Temperature rise
10.10 Dielectric withstand voltage tests
10.10.1 Applied potential withstand voltage test
10.10.2 Induced withstand voltage test
10.10.3 Lightning impulse withstand voltage test
10.10.4 Repetitive discharge test
10.11 Partial discharge test
10.12 Noise test
10.12.1 Test method
10.12.2 Background noise
10.12.3 Measuring method of transformer noise level
10.12.4 Calculation method of transformer noise level
10.12.5 Correction for background noise
10.13 Test for ability to withstand short-circuit
10.13.1 General
10.13.2 Thermal ability
10.13.3 Mechanical ability
10.14 Test for resistance to cracking
10.14.1 Methods for heating and cooling in the test
10.14.2 Test method
10.15 Test for resistance to damp heat
10.15.1 Humidifying method in the test
10.15.2 Test method
10.16 Flame retardance test
10.17 Construction test
11 Designation of product
12 Marking

Abstract

Defines transformers with a rated power not exceeding 500 kVA and a rated frequency of 50 Hz or 60 Hz in the category of 6 kV single-phase or three-phase indoor self-cooled encapsulated-winding transformers used for the purpose of general power distribution.

General Product Information

Published
Document Type	Standard
Status	Current
Publisher	Japanese Standards Association
Pages
ISBN
Supersedes	JIS C 4306:2005