1 Scope
This part gives guidance on variations to the specifications given in GB/T 3859.1 to enable the specification to be extended in a controlled form for special cases. Background information is also given on technical points which should facilitate the use of GB/T 3859.1.
This part primarily covers line commutated converters and is not in itself a specification, except as regards certain auxiliary components, in so far as existing standards may not provide the necessary data.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2900.33-2004 Electrotechnical Terminology — Power Electronics (IEC 60050-551:1998, IDT)
GB/T 3859.1-2013 Semiconductor Converters — General Requirements and Line Commutated Converters — Part 1-1: Specification of Basic Requirements (IEC 60146-1-1:2009, MOD)
GB/T 3859.3-2013 Semiconductor Converters — General Requirements and Line Commutated Converters — Part 1-3: Transformers and Reactors (IEC 60146-1-3:1991, MOD)
GB 4208 Degrees of Protection Provided by Enclosure (IP Code) (GB 4208-2008, IEC 60529:2001, IDT)
GB/T 10236 Guide for Compatibility and Protection of Interference Effects between Semiconductor Convertors and Power Supply System
GB/T 16935.1-2008 Insulation Coordination for Equipment within Low-voltage Systems — Part 1: Principles, Requirements and Tests (GB/T 16935.1-2008, IEC 60664-1:2007, IDT)
GB/T 17950 Semiconductor Converter — Part 6: Application Guide for the Protection of Semiconductor Converters Against Overcurrent by Fuses (GB/T 17950-2000, idt IEC 60146-6:1992)
GB/T 18494.1 Convertor Transformers — Part 1: Convertor Transformer for Industrial Applications (GB/T 18494.1-2001, idt IEC 61378-1:1997)
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 2900.33, GB/T 3859.1, several of which are repeated here for convenience, and the following apply.
3.1 Definitions related to converter faults
3.1.1
breakthrough
failure by which a controllable valve device or an arm consisting of such devices loses its ability to block voltage during the forward blocking interval
[GB/T 2900.34-2004, definition 551-16-60]
Note: Breakthrough can occur in rectifier operation as well as inverter operation and for various reasons, for example excessive junction temperature, voltage surges in excess of rated peak off-state voltage, excessive rate of rise of off-state voltage or spurious gate current. See Figure 1a).
... ...
.. ...
3.1.2
false firing
firing of a latching valve device or an arm consisting of such devices at an incorrect instant
[GB/T 2900.34-2004, definition 551-16-63]
3.1.3
breakdown (of an electronic valve device or of a valve arm)
failure that permanently deprives an electronic valve device or a valve arm of its property to block voltage
[GB/T 2900.34-2004, definition 551-16-66]
3.1.4
firing failure
failure to achieve conduction in a latching valve device or an arm consisting of such devices during the conduction interval
[GB/T 2900.34-2004, definition 551-16-65]
Note: See Figure 1b).
3.1.5
conduction through
in inverter operation, the situation that a valve arm continues conduction at the end of the normal conduction interval or at the end of the hold-off interval
[GB/T 2900.34-2004, definition 551-16-64]
Note: See Figure 1c).
3.1.6
commutation failure
failure to commutate the current from a conducting arm to the succeeding arm
[GB/T 2900.34-2004, definition 551-16-59]
3.2 Definitions related to converter generated transients
3.2.1
d.c. side transients
voltage transients produced by rapid changes of the d.c. voltage applied to the inductance and capacitance of the d.c. circuit
Note: See 7.4.
3.2.2
commutation transients on the line (repetitive transient)
voltage transients produced on the a.c. line after commutation
Note: See 7.4.
Foreword VI
1 Scope
2 Normative References
3 Terms and Definitions
3.1 Definitions related to converter faults
3.2 Definitions related to converter generated transients
3.3 Definitions related to temperature
3.4 Definitions related to harmonics
4 Performance of Converters and Conversion Systems
4.1 Application area
4.1.1 General
4.1.2 Conversion equipment and systems
4.1.3 Supply source conditioning (active and reactive power)
4.2 Main specification data
4.2.1 Main items on the specification
4.2.2 Additional information
4.2.3 Unusual service conditions
4.3 Converter transformers and reactors
4.4 Calculation factors
4.4.1 General
4.4.2 Voltage ratios
4.4.3 Line side transformer current factor
4.4.4 Valve-side transformer current factor
4.4.5 Voltage regulation
4.4.6 Magnetic circuit
4.4.7 Power loss factor
4.5 Parallel and series connections
4.5.1 Parallel or series connection of valve devices
4.5.2 Parallel or series connection of assemblies and equipment units
4.6 Power factor
4.6.1 General
4.6.2 Symbols used in the determination of displacement factor
4.6.3 Circle diagram for the approximation of the displacement factor cos?1N and of the reactive power Q1LN for rectifier and inverter operation
4.6.4 Calculation of the displacement factor cos?1
4.6.5 Conversion factor
4.7 Direct voltage regulation
4.7.1 General
4.7.2 Inherent direct voltage regulation
4.7.3 Direct voltage regulation due to a.c. system impedance
4.7.4 Information to be exchanged between supplier and purchaser about direct voltage regulation of the converter
4.8 Voltage limits for reliable commutation in inverter mode
4.9 A.C. voltage waveform
4.10 Circuit operating conditions affecting the voltage applied across converter valve devices
4.11 Overvoltage protection
4.12 Influence of environmental conditions on converter operation
5 Application Information
5.1 Practical calculation of the operating parameters
5.1.1 General
5.1.2 Assumptions
5.1.3 Preliminary calculations
5.1.4 Calculation of the operating conditions
5.2 Supply system voltage change due to converter loads
5.2.1 Fundamental voltage change
5.2.2 Minimum R1SC requirements for voltage change
5.2.3 Converter transformer ratio
5.2.4 Transformer rating
5.3 Compensation of converter reactive power consumption
5.3.1 Average reactive power consumption
5.3.2 Required compensation of the average reactive power
5.3.3 Voltage fluctuations with fixed reactive power compensation
5.4 Supply voltage distortion
5.4.1 Commutation notches
5.4.2 Operation of several converters on the same supply line
5.5 Quantities on the line side
5.5.1 R.M.S. value of the line current
5.5.2 Harmonics on the line side, approximate method for 6-pulse converters
5.5.3 Minimum R1SC requirements for harmonic distortion
5.5.4 Estimated phase shift of the harmonic currents
5.5.5 Addition of harmonic currents
5.5.6 Peak and average harmonic spectrum
5.5.7 Transformer phase shift
5.5.8 Sequential gating, two 6-pulse converters
5.6 Power factor compensation and harmonic distortion
5.6.1 General
5.6.2 Resonant frequency
5.6.3 Directly connected capacitor bank
5.6.4 Estimation of the resonant frequency
5.6.5 Detuning reactor
5.6.6 Ripple control frequencies (Carrier frequencies)
5.7 Direct voltage harmonic content
5.8 Other considerations
5.8.1 Random control angle
5.8.2 Sub-harmonic instability
5.8.3 Harmonic filters
5.8.4 Approximate capacitance of cables
5.9 Calculation of d.c. short-circuit current of converters
5.10 Guide-lines for the selection of the immunity class
5.10.1 General
5.10.2 Selection of the immunity class
6 Test Requirements
6.1 Guidance on power loss evaluation by short-circuit test
6.1.1 Single-phase connections
6.1.2 Polyphase double-way connections
6.1.3 Polyphase single-way connections
6.2 Procedure for evaluation of power losses by short-circuit method
6.3 Test methods
6.3.1 Method A1
6.3.2 Method B
6.3.3 Method C
6.3.4 Method D
6.3.5 Method E
6.3.6 Method A2
7 Performance Requirements
7.1 Presentation of rated peak load current values
7.2 Letter symbols related to virtual junction temperature
7.3 Determination of peak load capability through calculation of the virtual junction temperature
7.3.1 General
7.3.2 Approximation of the shape of power pulses applied to the semiconductor devices
7.3.3 The superposition method for calculation of temperature
7.3.4 Calculation of the virtual junction temperature for continuous load
7.3.5 Calculation of the virtual junction temperature for cyclic loads
7.3.6 Calculation of the virtual junction temperature for a few typical applications
8 Converter Operation
8.1 Stabilization
8.2 Static properties
8.3 Dynamic properties of the control system
8.4 Mode of operation of single and double converters
8.4.1 Single converter connection
8.4.2 Double converter connections and limits for rectifier and inverter operation
8.5 Transition current
8.6 Suppression of direct current circulation in double converter connections
8.6.1 General
8.6.2 Limitation of delay angles
8.6.3 Controlled circulating current
8.6.4 Blocking of trigger pulses
8.7 Principle of operation for reversible converters for control of d.c. motors
8.7.1 General
8.7.2 Motor field reversal
8.7.3 Motor armature reversal by reversing switch
8.7.4 Double converter connection to motor armature
9 Converter Faults
9.1 General
9.2 Fault finding
9.3 Protection from fault currents
Annex A (Informative) Overvoltage Protection Measures
Figure 1 Voltages at Converter Faults
Figure 2 Circle Diagram for Approximation of the Displacement Factor
Figure 3 Displacement Factor as a Function of dxN for p = 6
Figure 4 Displacement Factor as a Function of dxN for p = 12
Figure 5 dLN as a Function of dxN for p = 6 and p = 12
Figure 6 A.C. Voltage Waveform
Figure 7 Circuit Operating Conditions Affecting the Voltage Applied Across Converter Valve Devices
Figure 8 Overvoltage Protection Measures
Figure 9 Harmonic Current Spectrum on the a.c. Side for p = 6
Figure 10 Influence of Capacitor Rating and a.c. Motor Loads on the Resonant Frequency and Amplification Factor
Figure 11 Direct Voltage Harmonic Content for p = 6
Figure 12 Example of Power Distribution
Figure 13 Test Method A1
Figure 14 Test Method D
Figure 15 Single Peak Load
Figure 16 Repetitive Peak Loads
Figure 17 Approximation of the Shape of Power Pulses
Figure 18 Calculation of the Virtual Junction Temperature for Continuous Load
Figure 19 Calculation of the Virtual Junction Temperature for Cyclic Loads
Figure 20 Direct Voltage Waveform for Various Delay Angles
Figure 21 Direct Voltage for Various Loads and Delay Angles
Figure 22 Direct Voltage Limits in Inverter Operation
Figure 23 Direct Voltage at Values Below the Transition Current
Figure 24 Operating Sequences of Converters Serving a Reversible d.c. Motor
Figure A.1 Voltage/current characteristic of high voltage and high energy MOVs
Figure A.2 pulse derating curve of high voltage and high energy type MOVs
Figure A.3 Equivalent pulse derating curve of MOV (double logrithmic coordinates)
Figure A.4 Example for Connecting Position of MOV
Table 1 Connections and Calculation Factors
Table 2 List of Symbols Used in the Determination of Displacement Factor
Table 3 List of Symbols Used in the Calculation Formulae
Table 4 Example of Operating Conditions
Table 5 Example of Operating Points
Table 6 Example of Operating Conditions
Table 7 Result of the Iteration
Table 8 Example of Calculation Results of Active and Reactive Power Consumption
Table 9 Example of Notch Depth
Table 10 Example of Notch Depth by One Converter with a Common Transformer
Table 11 Example of Notch Depth by Ten Converters Operating at the Same Time
Table 12 The values of I′L(α,μ)/IL Under Different Trigger Delay Angle and Angle of Overlap
Table 13 Minimum R1SC Requirement for Low Voltage Systems
Table 14 Transformer Phase Shift and Harmonic Orders
Table 15 Approximate Values of Cables (kvar/km)
Table 16 Short-circuit Values of Converter Currents
Table 17 Calculated Values for the Example in Figure 12
Table 18 Letter Symbols Related to Virtual Junction Temperature
Table 19 Virtual Junction Temperature
