AS 1955.1-1977

1 - AS 1955 Part 1-1977 SEMICONDUCTOR CONVEERTORS - GENERAL
4 - PREFACE
5 - CONTENTS
6 - SECTION 1. GENERAL
6 - 1.1 Scope
6 - 1.2 Application
6 - 1.3 Reference to Other Specifications.
7 - 1.4 List of Principal Letter Symbols
7 - 1.4.1 General
7 - 1.4.2 List of Subscripts
7 - 1.4.3 List of Symbols
10 - 1.5 General Terms
10 - 1.5.1 Semiconductor rectifier diode (abbreviated to diode)
10 - 1.5.2 Reverse blocking triode thyristor
10 - 1.5.3 Diode stack
10 - 1.5.4 Thyristor stack
10 - 1.5.5 Diode assembly
10 - 1.5.6 Thyristor assembly
11 - 1.5.7 Convertor equipment (or convertor)
11 - 1.5.8 Trigger equipment
11 - 1.5.9 System control equipment
11 - 1.5.10 Convertor circuit element
11 - 1.5.11 By-pass diode (thyristor)
11 - 1.5.12 Convertor connection
11 - 1.5.13 Rectifier connection
11 - 1.5.14 Single-way connection (for examples, see Table II)
12 - 1.5.15 Double-way connection (for examples, see Table II)
12 - 1.5.16 Reversible power convertor (see also Clause 6.10)
12 - 1.5.17 Single-convertor (see Table II)
12 - 1.5.18 Double-convertor (see Table II)
12 - 1.5.19 Series convertor
12 - 1.5.20 Cascade convertor
12 - 1.5.21 Convertor with sequence control
12 - 1.5.22 Line or machine-commutated convertor
12 - 1.5.23 Commutation
13 - 1.5.24 Pulse number p
13 - 1.5.25 Commutating number q
13 - 1.5.26 Commutating group
13 - 1.5.27 Commutating voltages (commutating electromotive force)
13 - 1.5.28 Margin of commutation g (margin angle)
13 - 1.5.29 Overlap (angle) u
14 - 1.5.30 Delay angle a (Figure 1)
14 - 1.5.31 Inherent delay angle ap
14 - 1.5.32 Ideal crest no-load voltage Ui0m
14 - 1.5.33 Ideal crest voltage Uim
14 - 1.5.34 Equilibrium temperature
14 - 1.5.35 Designation of transformer windings
14 - 1.6 Definitions of rated values
14 - 1.6.1 Rated value
14 - 1.6.2 Definitions of rated values for convertor transformers
15 - 1.6.3 Definitions of rated values for assemblies and equipments
16 - 1.7 Efficiency definitions
16 - 1.7.1 Conversion factor
16 - 1.7.2 Power efficiency
16 - 1.8 Terms used in connection with convertor faults
16 - 1.8.1 Commutation failure
16 - 1.8.2 Conduction-through (shoot-through)
17 - 1.8.3 Missing
17 - 1.8.4 Breakthrough
17 - 1.8.5 Breakdown
17 - 1.9 Factors on a. c. side
17 - 1.9.1 Total power factor l
18 - 1.9.2 Power factor of the fundamental wave or displacement factor, cos j
18 - 1.9.3 Distortion factor v
18 - 1.10 Terms used in connection with voltage regulation
18 - 1.10.1 Conventional no-load direct voltage U d0
18 - 1.10.2 Ideal no-load direct voltage Udi0
18 - 1.10.3 Controlled ideal no-load direct voltage U di0a
19 - 1.10.4 Controlled conventional no-load direct voltage U d0a
19 - 1.10.5 Real no-load direct voltage U d00
19 - 1.10.6 Transition current
19 - 1.10.7 Voltage regulation
20 - 1.10.8 Corrected voltage regulation (stabilization)
20 - 1.10.9 Output effect
20 - 1.11 Terms used in connection with cooling
20 - 1.11.1 Cooling terms
21 - 1.11.2 Temperature definitions
21 - 1.12 Service conditions
21 - 1.13 A. C. system conditions
21 - 1.13.1 Waveform of alternating voltages
22 - 1.13.2 Symmetry of polyphase systems
22 - 1.13.3 A.C. system impedance
22 - 1.14 Temperature and cooling conditions
22 - 1.14.1 Temperature limits of cooling media for assemblies
22 - 1.15 Character of load
22 - 1.16 Usual service conditions
22 - 1.16.1 A.C line voltage variations
23 - 1.16.2 A.C. line frequency variations of ± 2%
23 - 1.16.3 Storage down to -10°C (with cooling liquid removed)
23 - 1.16.4 Operation including off-load periods down to:
23 - 1.16.5 An ambient temperature or cooling air temperature which does not exceed 40°C in the case of air cooling
23 - 1.16.6 An incoming cooling liquid temperature which does not exceed 30°C in the case of liquid cooling
23 - 1.17 Unusual service conditions
24 - 1.18 Performance of tests
24 - 1.19 Classification of tests
24 - 1.19.1 Type tests
24 - 1.19.2 Routine tests
25 - SECTION 2. SEMICONDUCTOR RECTIFIER DIODES AND THYRISTORS
25 - 2.1 General
26 - SECTION 3. TRANSFORMERS AND REACTORS
26 - 3.1 General
26 - 3.2 Rated values for convertor transformers
26 - 3.2.1 Rated current values
26 - 3.3 Temperature limits of cooling media
27 - 3.4 Losses and voltage drops in transformers and reactors
27 - 3.4.1 Losses in the transformer windings
27 - 3.5 Losses in interphase transformers, current-balancing reactors, series-smoothing reactors, transductors and other curren
27 - 3.5.1 Interphase transformer
27 - 3.5.2 Current balancing reactors
27 - 3.5.3 Series-smoothing reactor
27 - 3.5.4 Transductors and other current regulating reactors
28 - 3.6 Voltage drops in transformers and reactors
28 - 3.7 Tests for convertor transformers
28 - 3.8 Measurement of commutating reactance and determination of inductive voltage drop (type test)
29 - 3.9 Short-circuit test (type test and routine test)
29 - 3.10 Temperature-rise test (type test)
31 - SECTION 4. CONVERTOR EQUIPMENTS AND ASSEMBLIES
31 - 4.1 Electrical connections and calculation factors
31 - 4.1.1 Electrical connections
31 - 4.1.2 Calculation factors
35 - 4.2 Losses and efficiency, power factor and conversion factor
35 - 4.2.1 General about losses and efficiency
35 - 4.2.2 Included losses
36 - 4.2.3 Not-included losses
36 - 4.3 Power factor
41 - 4.4 Conversion factor
42 - 4.5 Voltage regulation
42 - 4.5.1 Inherent direct voltage regulation
44 - 4.5.2 Direct voltage regulation due to a. c. system impedance
47 - 4.5.3 Influence of existing convertors on d.c. voltage regulation on new plant to be installed
47 - 4.6 Harmonics in currents and voltages and associated effects
47 - 4.6.1 General
47 - 4.6.2 Order of harmonics
48 - 4.6.3 Harmonics in line current
48 - 4.6.4 Ripple voltage on the d.c. side
52 - 4.7 Symbols used in Figures 9 to 17
53 - 4.8 Alternating current components in d. c. load with a.c. impedance (capacitive load)
53 - 4.9 Circulating alternating currents in double convertors
53 - 4.10 Interference with other electrical equipment
53 - 4.10.1 General
54 - 4.10.2 For recommendations regarding interference with telephone lines, reference is made to the publications of C.C.I.T.T. and EEI-BTS mentioned in Clause 4.6.4.4.
54 - 4.11 Protection
54 - 4.11.1 Fault current protection
55 - 4.12 Overvoltage protection
55 - 4.12.1 Internal voltage surge
55 - 4.12.2 External voltage surge
55 - 4.13 Rated values for assemblies and equipments
55 - 4.13.1 General
56 - 4.13.2 Rated direct voltage
56 - 4.14 Rated current values
56 - 4.14.1 Current values to be specified
56 - 4.14.2 Duty classes
57 - 4.14.3 Basis of rated current values
58 - 4.14.4 Determination of requirements for rated current values
60 - 4.15 Particular remarks for double convertors
60 - 4.16 Tests for diode assemblies and rectifier equipments
60 - 4.16.1 General
61 - 4.16.2 Power loss determination for diode assemblies and rectifier equipments
65 - 4.17 Tests on small convertor equipments
65 - 4.17.1 Measurement of the inherent voltage regulation
65 - 4.17.2 Power loss measurements
66 - 4.17.3 Power factor measurements
66 - 4.17.4 Temperature-rise tests
66 - 4.18 Tests for thyristor assemblies and thyristor convertor equipments
66 - 4.18.1 General
67 - 4.19 Test specifications
67 - 4.19.1 Insulation tests
68 - 4.19.2 Light-load test
68 - 4.19.3 Current test
69 - 4.19.4 Checking of auxiliary devices
69 - 4.19.5 Power loss determination
70 - 4.19.6 Temperature-rise test
70 - 4.19.7 Load test
70 - 4.19.8 Checking the properties of the trigger equipment
71 - 4.19.9 Checking the co-ordination of protective devices
71 - 4.19.10 Checking properties under unusual service conditions
71 - 4.19.11 Checking properties of incorporated stabilization means
72 - SECTION 5. TOLERANCES
73 - SECTION 6. PERFORMANCE REQUIREMENTS AND APPLICATION INFORMATIONS
73 - 6.1 Parallel or series connection of diodes or thyristors
73 - 6.2 Current balancing of parallel connected devices
73 - 6.3 Voltage division for series connected devices
73 - 6.4 Parallel or series operation of assemblies and equipments
73 - 6.4.1 Parallel operation
73 - 6.4.2 Series operation
73 - 6.5 Auxiliaries to rectifier or convertor equipments
74 - 6.6 Voltage limits for reliable commutation in inverter mode of operation
74 - 6.7 Overload conditions
74 - 6.7.1 Presentation of rated overload current values
75 - 6.7.2 Determination of overload capability through calculation of virtual junction temperature
75 - 6.8 Stabilization
75 - 6.8.1 Static properties
75 - 6.8.2 Dynamic properties of the control system
76 - 6.9 Mode of operation of single and double convertors
76 - 6.9.1 Single convertor connection
78 - 6.9.2 Double convertor connections
78 - 6.9.3 Transition current
80 - 6.9.4 Working limit lines for rectifier and inverter operation
80 - 6.9.5 Suppression of circulating direct current in double convertor connections
81 - 6.9.6 Suppression of circulating alternating current in double convertor connections
81 - 6.10 Principle of operation for reversible convertors for control of d. c. motors
81 - 6.10. 1 Motor field reversal
81 - 6.10. 2 Motor armature reversal by reversing switch
81 - 6.10. 3 Double convertor connection to motor armature
83 - 6.11 Circuit operating conditions affecting the voltage applied across convertor circuit elements
84 - SECTION 7. MARKINGS ON CONVERTOR EQUIPMENTS AND ASSEMBLIES
84 - 7.1 Markings
84 - 7.2 Rating plate
84 - 7.2.1 Rating plates of equipments
85 - 7.2.2 Rating plates of assemblies
85 - 7.2.3 Rating plates of convertor transformers
85 - 7.2.4 Items which may be added if appropriate
86 - APPENDIX A - SEMICONDUCTOR RECTIFIER DIODES AND DIODE STACKS
86 - A1 Definitions
88 - A2 Rated values and characteristics
92 - A3 Tests for diodes and diode stacks
101 - A4 Marking
102 - APPENDIX B - THYRISTORS AND THYRISTOR STACKS
102 - B1 Definitions
107 - B2 Rated values and characteristics
112 - B3 Tests for thyristors and thyristor stacks
130 - B4 Marking
131 - APPENDIX C - CORRECTIONS TO BE APPLIED WHEN COOLING MEDIUM TEMPERATURE IS HIGHER THAN STANDARD
131 - C1 General Application.
132 - APPENDIX D - DETERMINATION OF OVERLOAD CAPABILITY THROUGH CALCULATION OF VIRTUAL JUNCTION TEMPERATURE
132 - D1 Definitions and letter symbols used for the calculations
132 - D2 Approximation of the shape for power pulse applied to the semiconductor device
133 - D3 The superposition method for calculation of temperature
134 - D4 Calculation of virtual junction temperature for continuous load
135 - D5 Calculation of virtual junction temperature for cycling load
136 - D6 Calculation formulae for a few typical applications

Defines the terminology and specifies letter symbols, requirements and test for use with semiconductor diodes and thyristors. The Standard is based on and is technically similar to IEC 146-1.

This standard specifies requirements for semicondutor rectifiers, diodes and thyristors, convertor* transformers and reactors, and convertor equipments and assemblies together with tolerances on rated values and conditions, and performance requirements and application information. In addition, letter symbols and definitions are provided for terms used in conjunction with such devices and equipments.ApplicationThis standard applies to static power convertors of the line- or machine-commutated type for conversion from a.c. to d.c. or from d.c. to a.c., i.e. rectifiers, inverters and convertors embodying both modes of operation. It applies also to convertors for control of alternating voltage and convertors in which the commutating voltage is supplied by the load circuit, e.g. a resonating load.The standard is restricted to convertors with semiconductor rectifier diodes, reverse blocking triode thyristors or a combination of these, but it may also be applied for convertors with bidirectional thyristors in so far as applicable. The term 'thyristor' is used in the standard as an abbreviation for reverse blocking triode thyristor.The standard does not apply to convertors in which the commutating voltage is supplied by internal sources, e g. capacitors, frequency convertors, convertors used in telecommunication apparatus other than for power supplied to such equipment, to auxiliaries of measuring instruments, or system control equipments for control of static power convertors.Special kinds of convertors, e.g. convertors for adjustable speed d.c. motor drives, power convertors for electric traction, convertors for control of alternating voltage, self-commutated inverters, d.c. to d.c. convertors, etc, are not covered by this standard.

Reconfirmed 1983
Under revision See DR 02098-02100 CP