Table of Contents

Cover

Title Page

Preface

Acknowledgments

Chapter 1: Definitions: Methods of Calculations

1.1 Time Behavior of the Short-Circuit Current
1.2 Short-Circuit Path in the Positive-Sequence System
1.3 Classification of Short-Circuit Types
1.4 Methods of Short-Circuit Calculation

Chapter 2: Fault Current Analysis

Chapter 3: The Significance of IEC 60909-0

Chapter 4: Supply Networks

4.1 Calculation Variables for Supply Networks
4.2 Lines Supplied from a Single Source
4.3 Radial Networks
4.4 Ring Networks
4.5 Meshed Networks

Chapter 5: Network Types for the Calculation of Short-Circuit Currents

5.1 Low-Voltage Network Types
5.2 Medium-Voltage Network Types
5.3 High-Voltage Network Types

Chapter 6: Systems up to 1 kV

6.1 TN Systems
6.2 Calculation of Fault Currents
6.3 TT systems
6.4 IT Systems
6.5 Transformation of the Network Types Described to Equivalent Circuit Diagrams
6.6 Examples

Chapter 7: Neutral Point Treatment in Three-Phase Networks

7.1 Networks with Isolated Free Neutral Point
7.2 Networks with Grounding Compensation
7.3 Networks with Low-Impedance Neutral Point Treatment
7.4 Examples

Chapter 8: Impedances of Three-Phase Operational Equipment

8.1 Network Feed-Ins, Primary Service Feeder
8.2 Synchronous Machines
8.3 Transformers
8.4 Cables and Overhead Lines
8.5 Short-Circuit Current-Limiting Choke Coils
8.6 Asynchronous Machines
8.7 Consideration of Capacitors and Nonrotating Loads
8.8 Static Converters
8.9 Wind Turbines
8.10 Short-Circuit Calculation on Ship and Offshore Installations
8.11 Examples

Chapter 9: Impedance Corrections

9.1 Correction Factor K_G for Generators
9.2 Correction Factor K_KW for Power Plant Block
9.3 Correction Factor K_T for Transformers with Two and Three Windings

Chapter 10: Power System Analysis

10.1 The Method of Symmetrical Components
10.2 Fundamentals of Symmetrical Components
10.3 General Description of the Calculation Method
10.4 Impedances of Symmetrical Components

Chapter 11: Calculation of Short-Circuit Currents

11.1 Three-Phase Short Circuits
11.2 Two-Phase Short Circuits with Contact to Ground
11.3 Two-Phase Short Circuit Without Contact to Ground
11.4 Single-Phase Short Circuits to Ground
11.5 Peak Short-Circuit Current, i_p
11.6 Symmetrical Breaking Current, I_a
11.7 Steady-State Short-Circuit Current, I_k

Chapter 12: Motors in Electrical Networks

12.1 Short Circuits at the Terminals of Asynchronous Motors
12.2 Motor Groups Supplied from Transformers with Two Windings
12.3 Motor Groups Supplied from Transformers with Different Nominal Voltages

Chapter 13: Mechanical and Thermal Short-Circuit Strength

13.1 Mechanical Short-Circuit Current Strength
13.2 Thermal Short-Circuit Current Strength
13.3 Limitation of Short-Circuit Currents
13.4 Examples for Thermal Stress

Chapter 14: Calculations for Short-Circuit Strength

14.1 Short-Circuit Strength for Medium-Voltage Switchgear
14.2 Short-Circuit Strength for Low-Voltage Switchgear

Chapter 15: Equipment for Overcurrent Protection

Chapter 16: Short-Circuit Currents in DC Systems

16.1 Resistances of Line Sections
16.2 Current Converters
16.3 Batteries
16.4 Capacitors
16.5 Direct Current Motors

Chapter 17: Power Flow Analysis

17.1 Systems of Linear Equations
17.2 Determinants
17.3 Network Matrices

Chapter 18: Examples: Calculation of Short-Circuit Currents

18.1 Example 1: Radial Network
18.2 Example 2: Proof of Protective Measures
18.3 Example 3: Connection Box to Service Panel
18.4 Example 4: Transformers in Parallel
18.5 Example 5: Connection of a Motor
18.6 Example 6: Calculation for a Load Circuit
18.7 Example 7: Calculation for an Industrial System
18.8 Example 8: Calculation of Three-Pole Short-Circuit Current and Peak Short-Circuit Current
18.9 Example 9: Meshed Network
18.10 Example 10: Supply to a Factory
18.11 Example 11: Calculation with Impedance Corrections
18.12 Example 12: Connection of a Transformer Through an External Network and a Generator
18.13 Example 13: Motors in Parallel and their Contributions to the Short-Circuit Current
18.14 Example 14: Proof of the Stability of Low-Voltage Systems
18.15 Example 15: Proof of the Stability of Medium-Voltage and High-Voltage Systems
18.16 Example 16: Calculation for Short-Circuit Currents with Impedance Corrections

Bibliography

Standards

Explanations of Symbols

Symbols and Indices

Indices
Secondary Symbols, Upper Right, Left
American Cable Assembly (AWG)

Index

End User License Agreement

List of Illustrations

Chapter 1: Definitions: Methods of Calculations

Figure 1.1 Time behavior of the short-circuit current (see Ref. [1]). (a) Far-from-generator short circuit and (b) near-to-generator short circuit. $c01-math-002$ : initial symmetrical short-circuit current; i_p: peak short-circuit current; i_d.c.: decaying d.c. aperiodic component; and A: initial value of d.c. aperiodic component.
Figure 1.2 Equivalent circuit of the short-circuit current path in the positive-sequence system.
Figure 1.3 Switching processes of the short circuit.
Figure 1.4 Types of short-circuit currents in three-phase networks [1].
Figure 1.5 Methods for the short-circuit calculation. (a) Single line diagram; (b) voltage source at the fault location; (c) superposition; and (d) equivalent voltage source.
Figure 1.6 Network circuit with equivalent voltage source [2]. (a) System diagram and (b) equivalent circuit diagram of the positive-sequence system.
Figure 1.7 Short-circuit current components – switch on.
Figure 1.8 Switching process.
Figure 1.9 Impact of engines on the current.
Figure 1.10 Supply for an industrial company.
Figure 1.11 Equivalent circuit diagram in positive sequence.
Figure 1.12 Power plant with auxiliary power system.
Figure 1.13 Equivalent circuit diagram in positive sequence.
Figure 1.14 Result with NEPLAN.

Chapter 3: The Significance of IEC 60909-0

Figure 3.1 Range of applicability of short-circuit calculations [1, 2].

Chapter 4: Supply Networks

Figure 4.1 Overview of a power transmission and distribution system.
Figure 4.2 Line supplied from a single source.
Figure 4.3 Radial network.
Figure 4.4 Ring network.
Figure 4.5 Meshed network.

Chapter 5: Network Types for the Calculation of Short-Circuit Currents

Figure 5.1 Simple radial networks with different centers of load distribution.
Figure 5.2 Simple radial networks with individual load circuits.
Figure 5.3 Simple radial networks with redundant inputs.
Figure 5.4 Meshed network with different inputs and network nodes with fuses.
Figure 5.5 Industrial load center network.
Figure 5.6 Industrial ring network.
Figure 5.9 Short circuit with simple inputs.
Figure 5.7 (a) Ring network, (b) network with remote station, and (c) network supporting structure.
Figure 5.8 Network configuration for medium-voltage systems.
Figure 5.9 Short circuit with simple inputs.
Figure 5.10 380/110 kV-substation.
Figure 5.12 Generation, transmission, and distribution system.

Chapter 6: Systems up to 1 kV

Figure 6.1 Circuitry of the TN–C–S system.
Figure 6.2 Circuitry of the TN system. (a) Distribution systems, (b) loop impedance, and (c) fault location.
Figure 6.3 Overview of the power supply.
Figure 6.4 Circuitry of the TT system.
Figure 6.5 Circuitry of the IT system.
Figure 6.6 Network transformations. (a) Series circuit, (b) parallel circuit, (c) delta–star transformation, and (d) star–delta transformation.
Figure 6.7 Automatic disconnection for a TN system.

Chapter 7: Neutral Point Treatment in Three-Phase Networks

Figure 7.1 Neutral point treatment of transformers.
Figure 7.2 Surface potential profile and voltages in case of current-carrying earth electrodes (see also Ref. [2]).
Figure 7.3 Isolated network and equivalent circuit diagram.
Figure 7.4 Network with earth fault compensation.
Figure 7.5 Low-resistance grounded network and equivalent diagram.

Chapter 8: Impedances of Three-Phase Operational Equipment

Figure 8.1 Network feed-in and equivalent circuit. (a) System diagram and equivalent circuit diagram without transformer and (b) system diagram and equivalent circuit diagram with transformer.
Figure 8.2 Synchronous machine.
Figure 8.3 Synchronous machine in different operative conditions.
Figure 8.4 Equivalent circuit and phasor diagram of the synchronous machine in the positive sequence.
Figure 8.5 Generator near the short-circuit current.
Figure 8.6 Synchronous machine and the equivalent circuit diagram.
Figure 8.7 Overview of a transformer.
Figure 8.8 Transformer and equivalent circuit.
Figure 8.9 Equivalent resistances and reactances in the zero-sequence and positive-sequence systems for LV transformers.
Figure 8.10 (a) Circuit diagram for a transformer with three windings and (b) equivalent circuit with side C open.
Figure 8.11 Equivalent resistances and reactances of transformers for LV and MV networks [7].
Figure 8.12 Cables and lines in the positive-sequence system.
Figure 8.13 The basis of calculation for overhead lines: (a) equivalent circuit of an overhead line; (b) 4× conductor bundle line; (c) 2× conductor bundle line; and (d) mast diagram.
Figure 8.14 (a) Short-circuit current-limiting choke coil, equivalent circuit; and (b) application.
Figure 8.15 Overview of an asynchronous machine (ABB).
Figure 8.16 Asynchronous machine and equivalent circuit.
Figure 8.17 Connection to the HV power network.
Figure 8.18 Wind power plant with asynchronous generator.
Figure 8.19 Wind power plant with a doubly fed asynchronous generator.
Figure 8.20 Wind power with full converter.
Figure 8.21 Wind power with full converter.
Figure 8.22 Equivalent circuit diagram of a star-to-star (Y–Y) transformer in zero sequence.
Figure 8.23 Diagram to assign failure with maximal current [12].
Figure 8.24 Diagram of a one-phase short circuit in partial network.
Figure 8.25 Symmetrical components of a partial network.
Figure 8.26 Impedances for calculating a three-phase short-circuit.
Figure 8.27 Characteristic diagram of high-voltage fuses.
Figure 8.28 Characterization diagram of high-voltage fuse flow operating to a circuit breaker.
Figure 8.29 Factor k.
Figure 8.30 Factor m and parameter k.
Figure 8.31 Circuit diagram of NPT with Y–Δ winding.
Figure 8.32 Circuit diagram of NPT with Z–Z winding.
Figure 8.33 Diagram of a branch without an NPT.
Figure 8.34 Symmetrical components of branch without an NPT.
Figure 8.35 Diagram of a branch with an NPT.
Figure 8.36 Symmetrical components of branch with an NPT.
Figure 8.37 Diagram of a short circuit divided.

Chapter 9: Impedance Corrections

Figure 9.1 Connection and equivalent circuit of a generator.
Figure 9.2 Impedance correction for power station.

Chapter 10: Power System Analysis

Figure 10.1 Delta and star (wye) connection with neutral point (N).
Figure 10.2 Phasor diagram for the positive-sequence, negative-sequence, and zero-sequence systems.
Figure 10.3 Power transmission, three-phase system.
Figure 10.4 Schematic of a three-phase network and relationship between components of positive-sequence, negative-sequence, and zero-sequence systems. (a) Unsymmetrical system, (b) Symmetrical system, (c) equivalent one-line diagram of the components, and (d) graphical addition of three components.
Figure 10.5 Circuit diagram of a one-phase short circuit.
Figure 10.6 Equivalent circuits for positive-sequence, negative-sequence, and zero-sequence systems.
Figure 10.7 Measuring circuits for determining the positive-sequence, negative-sequence, and zero-sequence impedances (see also Ref. [1]).
Figure 10.8 Schematic of the equivalent circuit components.
Figure 10.9 Schematic diagram of three-phase delta, star source, and loads. (a) Source and (b) load.

Chapter 11: Calculation of Short-Circuit Currents

Figure 11.1 Equivalent circuit for a three-phase short circuit with equivalent voltage source at the position of the fault.
Figure 11.2 Equivalent circuit of a two-phase short circuit with contact to ground.
Figure 11.3 Vector diagram of the two-phase short circuit with earth contact.
Figure 11.4 Equivalent circuit of a two-phase short circuit without contact to ground.
Figure 11.5 Vector diagram of the two-phase short circuit without earth contact.
Figure 11.6 Equivalent circuit of single-phase short circuit to ground.
Figure 11.7 Vector diagram of the one-phase short circuit.
Figure 11.8 Largest short-circuit currents for asymmetrical short circuits (see also Ref. [1]).
Figure 11.9 Factor κ for calculating the peak short-circuit current i_p (see also Ref. [1]).
Figure 11.10 Factor μ for calculating the symmetrical breaking current I_a (see also Ref. [1]).
Figure 11.11 Factor q for calculation of the symmetrical breaking current for asynchronous machines (see also Ref. [1]).
Figure 11.12 Factors λ_min and λ_max for calculating the steady-state short- circuit current I_k (see also Ref. [1]).

Chapter 12: Motors in Electrical Networks

Figure 12.1 Short circuit at the terminals of an asynchronous motor.
Figure 12.2 Motor groups supplied from transformers with two windings.
Figure 12.3 Motor groups supplied from transformers with different nominal voltages.

Chapter 13: Mechanical and Thermal Short-Circuit Strength

Figure 13.1 Effects of forces acting on busbars and parallel conductors (see also Ref. [6]).
Figure 13.2 Correction factor k₁₂ for the determination of the effective conductor spacing a_m (see also Ref. [1]).
Figure 13.3 The factors m and n (see also Ref. [1]).
Figure 13.4 Rated short-time current density S_thr for T_kr = 1 s (a) for copper and steel (solid line curves), (b) aluminum (broken line curves) Aldrey and Al/St (see also Ref. [17]).
Figure 13.5 Current limitation through circuit breaker: (a) high power current limitation through circuit breaker and (b) line protection circuit breaker with neutral point quencher, without definite current limitation.
Figure 13.6 Thermally permissible short-circuit current from paper-insulated cables at 1–10 kV (see also Ref. [10]).
Figure 13.7 Thermally permissible short-circuit current from paper-insulated cables at 12/20 kV (see also Ref. [10]).
Figure 13.8 Thermally permissible short-circuit current from paper-insulated cables at 18/30 kV (see also Ref. [10]).
Figure 13.9 Thermally permissible short-circuit current from PVC-insulated cables at 1–10 kV (see also Ref. [10]).
Figure 13.10 Thermally permissible short-circuit current from XLPE-insulated cables (see also Ref. [10]).
Figure 13.11 Thermally permissible short-circuit current of Cu screening (see also Ref. [10]).
Figure 13.12 Feeder of a transformer.
Figure 13.13 Mechanical short-circuit strength.
Figure 13.14 Busbar configuration.

Chapter 15: Equipment for Overcurrent Protection

Figure 15.1 Overview of overcurrent protective devices.
Figure 15.2 Time–current characteristics of limit switch fuses in accordance with IEC 60269-2 (2–1 000 A). (1) Peak current without d.c. part and (2) peak current with d.c. part.
Figure 15.3 Time–current characteristics of limit switch fuses in accordance with IEC 60269-2. (1) Small test current and (2) large test current.
Figure 15.4 Time–current characteristics of limit switch fuses in accordance with IEC 60269-2 (4–1250 A).
Figure 15.5 Time–current characteristics of limit switch fuses in accordance with IEC 60269-2. (1) Small test current and (2) large test current.
Figure 15.6 Time–current characteristics of high voltage–high power (HH) fuses in accordance with IEC 60282-1.
Figure 15.7 Application of fuses in power systems.
Figure 15.8 Time–current characteristics of miniature circuit breakers in accordance with IEC 60898-1.
Figure 15.9 Tripping curves with thermal relays for different starting classes.
Figure 15.10 Tripping curves with motor protection device.
Figure 15.11 Time–current characteristics of circuit breakers.

Chapter 16: Short-Circuit Currents in DC Systems

Figure 16.1 Typical paths for short-circuit currents.
Figure 16.2 Standardized approximation functions.
Figure 16.3 Equivalent circuit for the calculation of short-circuit currents.
Figure 16.4 Equivalent circuit of a converter arm.
Figure 16.5 Equivalent circuit of a battery.
Figure 16.6 Equivalent circuit of a capacitor.
Figure 16.7 Equivalent circuit of an externally excited DC motor.

Chapter 17: Power Flow Analysis

Figure 17.1 Network section with the nodes i and k and the reference point 0.
Figure 17.2 Calculation of the line currents between two nodes i, k from the node voltages $c017-math-049$ , $c017-math-050$ and the branch impedance $c017-math-051$ with (a) a constant current and (b) constant power.
Figure 17.3 Representation of a power system.
Figure 17.4 Circuit diagrams for power flow calculations.
Figure 17.5 One-line diagram and equivalent circuit.
Figure 17.6 Flow diagram.
Figure 17.7 Illustration of the Newton–Raphson algorithm.
Figure 17.8 Equivalent circuits for power flow calculations.
Figure 17.9 Application of Cramer's rule.
Figure 17.10 Power flow calculation with NEPLAN.

Chapter 18: Examples: Calculation of Short-Circuit Currents

Figure 18.1 Example 1: network representation.
Figure 18.2 Example 2: calculation with source impedance.
Figure 18.3 Example 3: power plant network with service panel.
Figure 18.4 Example 4: transformers in parallel.
Figure 18.5 Equivalent circuit.
Figure 18.6 Example 5: connection of a motor.
Figure 18.7 Example 6: Calculation for a load.
Figure 18.8 Equivalent circuit for $c018-math-009$ .
Figure 18.9 Example 7: network diagram.
Figure 18.10 Example 8: network diagram.
Figure 18.11 Meshed network.
Figure 18.12 Delta star transformations.
Figure 18.13 Supply to a factory.
Figure 18.14 Calculation with impedance corrections.
Figure 18.15 Example 12: connection of a transformer through an external network and a generator.
Figure 18.16 Example 13: influence of motors on the current.
Figure 18.17 Network design – single-phase representation with network input and transformers.
Figure 18.18 Operational equipment with equivalent circuit.
Figure 18.19 Equivalent circuit in the positive-sequence system at fault location F1.
Figure 18.20 Equivalent circuit in the positive-sequence system at fault location F2.
Figure 18.21 Equivalent circuit in the positive-sequence system at fault location F3.
Figure 18.22 Dimensioning of the circuit breakers ; (1) input field, (2) load field, and (3) coupling field.
Figure 18.23 Example 16: Calculation of short-circuit currents with impedance corrections.

List of Tables

Chapter 1: Definitions: Methods of Calculations

Table 1.1 Voltage factor c, according to IEC 60909-0: 2016-10 [1]

Chapter 3: The Significance of IEC 60909-0

Table 3.1 Selection of short-circuit currents.

Chapter 7: Neutral Point Treatment in Three-Phase Networks

Table 7.1 Decisive currents for the dimensioning of grounding systems [2]
Table 7.2 Summary of the isolated network
Table 7.3 Summary of the compensated network
Table 7.4 Summary of the low-resistance grounded network
Table 7.5 Arrangement of neutral point
Table 7.6 Application of neutral point arrangements

Chapter 8: Impedances of Three-Phase Operational Equipment

Table 8.1 Reactances of a synchronous machine [6]
Table 8.2 Characteristic values of high-voltage (HV) transformers
Table 8.3 Impedances for polyvinyl chloride (PVC)-insulated three-phase NYY cables [8]
Table 8.4 Resistance values for PVC-insulated four- and five-conductor cables with copper conductors at 55 °C conductor temperature [8]
Table 8.5 Resistance values for PVC-insulated 3.5- and 4.5-conductor three-phase cables with copper conductors at 55 °C conductor temperature [8]
Table 8.6 Resistance values for PVC-insulated single-conductor three-phase cables with PE or PEN next to each other, with copper conductors at 55 °C conductor temperature [8]
Table 8.7 Resistance values for PVC-insulated single-conductor three-phase cables with PE or PEN at a distance d from each other, with copper conductors at 55 °C conductor temperature [8]
Table 8.8 Resistance values at 80 °C for copper cables and conductors [9]
Table 8.9 Resistance values at 20 °C for copper cables and conductors [9]
Table 8.10 Resistances per unit length r in a positive-sequence system for overland line conductors manufactured in accordance with DIN 48 201 and f = 50 Hz at 20 °C [9]
Table 8.11 Inductive reactances per unit length x in Ω/km in a positive-sequence system for overland line conductors at f = 50 Hz [9]
Table 8.12 Quotients of effective resistances and inductive reactances in the zero-sequence and positive-sequence systems for NAYY and NYY cables as a function of the ground return system at f = 50 Hz [9]
Table 8.13 Resistances r per unit length of conductors for copper conductors.
Table 8.14 Impedance z for main outgoing and return lines of power supply companies
Table 8.15 Resistances of conductors in XLPE-insulated cables (6–30 kV) at 20 °C [10]
Table 8.16 Resistances per unit length of XLPE-insulated copper cables (6–20 kV) for f = 50 Hz [10]
Table 8.17 Inductances of XLPE-insulated copper cables (6–30 kV) for f = 50 Hz [10]
Table 8.18 Effective capacitances of XLPE-insulated copper cables [10]
Table 8.19 Ground fault currents of XLPE-insulated copper cables [11]
Table 8.20 Rating of the ground short-circuit current I″_k2E
Table 8.21 Results of the minimal one-phase short-circuit calculation in NEPLAN with a cable temperature of 80 °C
Table 8.22 Results of the minimal one-phase short-circuit calculation in NEPLAN with a cable temperature of 160 °C
Table 8.23 Maximal one-phase short-circuit currents with and without a connected NPT

Chapter 9: Impedance Corrections

Table 9.1 Impedance corrections

Chapter 12: Motors in Electrical Networks

Table 12.1 Calculation of short circuits at the terminals of motors

Chapter 13: Mechanical and Thermal Short-Circuit Strength

Table 13.2 Factors α and β for different support point arrangements (see also Ref. [6])
Table 13.1 Moments of resistance and moments of inertia

Chapter 18: Examples: Calculation of Short-Circuit Currents

Table 18.1 Summary of results
Table 18.2 Summary of results for $c018-math-025$ at subdistributor
Table 18.5 Summary of results for $c018-math-031$ at load
Table 18.6 Checking the short-circuit strength
Table 18.7 Current carrying capacities for the 110/20-kV level
Table 18.8 Rated voltages for the 110/20-kV level
Table 18.9 Selection values and rated values for load interrupter switches in accordance with IEC 282
Table 18.10 Selection values and rated values for load interrupter switches in accordance with IEC 282
Table 18.11 Selection values and rated values for disconnect switches and grounding switches in accordance with IEC 282
Table 18.12 Dimensioning of the circuit breakers
Table 18.13 Dimensioning the circuit breakers at different connection points on the busbar

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Preface

This book is the result of many years of professional activity in the area of power supply, teaching at the VDE, as well as at the Technical Academy in Esslingen. Every planner of electrical systems is obligated today to calculate the single-pole or three-pole short-circuit current before and after the project management phase. IEC 60909-0 is internationally recognized and used. This standard will be discussed in this book on the basis of fundamental principles and technical references, thus permitting a summary of the standard in the simplest and most understandable way possible. The rapid development in all areas of technology is also reflected in the improvement and elaboration of the regulations, in particular in regard to IEC 60909-0. Every system installed must not only be suitable for normal operation, but must also be designed in consideration of fault conditions and must remain undamaged following operation under normal conditions and also following a fault condition. Electrical systems must therefore be designed so that neither persons nor equipment are endangered. The dimensioning, cost effectiveness, and safety of these systems depend to a great extent on being able to control short-circuit currents. With increasing power of the installation, the importance of calculating short-circuit currents has also increased accordingly. Short-circuit current calculation is a prerequisite for the correct dimensioning of operational electrical equipment, controlling protective measures and stability against short circuits in the selection of equipment. Solutions to the problems of selectivity, back-up protection, protective equipment, and voltage drops in electrical systems will not be dealt with in this book. The reduction factors, such as frequency, temperatures other than the normal operating temperature, type of wiring, and the resulting current carrying capacity of conductors and cables will also not be dealt with here.

This book comprises the following sections:

Chapter 1 describes the most important terms and definitions, together with relevant processes and types of short circuits.

Chapter 2 is an overview of the fault current analysis.

Chapter 3 explains the significance, purpose, and creation of IEC 60909-0.

Chapter 4 deals with the network design of supply networks.

Chapter 5 gives an overview of the network types for low, medium and high- voltage network.

Chapter 6 describes the systems (network types) in the low-voltage network (IEC 60364) with the cut-off conditions.

Chapter 7 illustrates the types of neutral point treatment in three-phase networks.

Chapter 8 discusses the impedances of the three-phase operational equipment along with relevant data, tables, diagrams, and characteristic curves.

Chapter 9 presents the impedance corrections for generators, power substation transformers, and distribution transformers.

Chapter 10 is concerned with the power system analysis and the method of symmetrical components. With the exception of the three-pole short-circuit current, all other fault currents are unsymmetrical. The calculation of these currents is not possible in the positive-sequence system. The method of symmetrical components is therefore described here.

Chapter 11 is devoted to the calculation of short-circuit types.

Chapter 12 discusses the contribution of high-voltage and low-voltage motors to the short-circuit current.

Chapter 13 deals with the subject of mechanical and thermal stresses in operational equipment as a result of short-circuit currents.

Chapter 14 gives an overview of the design values for short-circuit current strength.

Chapter 15 is devoted to the most important overcurrent protection devices, with time–current characteristics.

Chapter 16 gives a brief overview of the procedure for calculating short-circuit currents in DC systems.

Chapter 17 gives an introduction into power flow analysis.

Chapter 18 represents a large number of examples taken from practice which enhance the understanding of the theoretical foundations. A large number of diagrams and tables that are required for the calculation simplify the application of the IEC 60909 standard as well as the calculation of short-circuit currents and therefore shorten the time necessary to carry out the planning of electrical systems.

I am especially indebted to Dr.-Ing. Waltraud Wüst, Dr. Martin Preuss from Wiley-VCH and Kishore Sivakolundu from SPI for critically reviewing the manuscript and for valuable suggestions.

At this point, I would also like to express my gratitude to all those colleagues who supported me with their ideas, criticism, suggestions, and corrections. My heartiest appreciation is due to Wiley Press for the excellent cooperation and their support in the publication of this book.

Furthermore, I welcome every suggestion, criticism, and idea regarding the use of this book from those who read the book.

Finally, without the support of my family this book could never have been written. In recognition of all the weekends and evenings I sat at the computer, I dedicate this book to my family.

Ismail Kasikci

Weinheim
21.07.2017

Short Circuits in Power Systems

A Practical Guide to IEC 60909-0

Preface

Acknowledgments