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- Herausgeber: Wiley-VCH GmbH
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
- Veröffentlichungsjahr: 2022
A one-stop resource on how to design standard-compliant low voltage electrical systems This book helps planning engineers in the design and application of low voltage networks. Structured according to the type of electrical system, e.g. asynchronous motors, three-phase networks, or lighting systems, it covers the respective electrical and electrotechnical fundamentals, provides information on the implementation of the relevant NEC and IEC standards, and gives an overview of applications in industry. Analysis and Design of Electrical Power Systems: A Practical Guide and Commentary on NEC and IEC 60364 starts by introducing readers to the subject before moving on to chapters on planning and project management. It then presents readers with complete coverage of medium- and low-voltage systems, transformers, asynchronous motors (ASM), switchgear combinations, emergency generators, and lighting systems. It also looks at equipment for overcurrent protection and protection against electric shock, as well as selectivity and backup protection. A chapter on the current carrying capacity of conductors and cables comes next, followed by ones on calculation of short circuit currents in three-phase networks and voltage drop calculations. Finally, the book takes a look at compensating for reactive power and finishes with a section on lightning protection systems. -Covers a subject of great international importance -Features numerous tables, diagrams, and worked examples that help practicing engineers in the planning of electrical systems -Written by an expert in the field and member of various national and international standardization committees -Supplemented with programs on an accompanying website that help readers reproduce and adapt calculations on their own Analysis and Design of Electrical Power Systems: A Practical Guide and Commentary on NEC and IEC 60364 is an excellent resource for all practicing engineers such as electrical engineers, engineers in power technology, etc. who are involved in electrical systems planning.
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Table of Contents
Cover
Title Page
Copyright
Preface
Acknowledgments
Symbols
Abbreviations
1 Introduction
2 Electrical Systems
2.1 High‐Voltage Power Systems
2.2 Transformer Selection Depending on Load Profiles
2.3 Low‐Voltage Power Systems
2.4 Examples of Power Systems
3 Design of DC Current Installations
3.1 Earthing Arrangement
3.2 Protection Against Overcurrent
3.3 Architecture of Installations
4 Smart Grid
5 Project Management
5.1 Guidelines for Contracting
5.2 Guidelines for Project Planning of Electrical Systems
6 Three‐Phase Alternating Current
6.1 Generation of Three‐Phase Current
6.2 Advantages of the Three‐Phase Current System
6.3 Conductor Systems
6.4 Star Connection
6.5 Triangle Circuit
6.6 Three‐Phase Power
6.7 Example: Delta Connection
6.8 Example: Star Connection
6.9 Example: Three‐Phase Consumer
6.10 Example: Network Calculation
6.11 Example: Network
6.12 Example: Star Connection
7 Symmetrical Components
7.1 Symmetrical Network Operation
7.2 Unsymmetrical Network Operation
7.3 Description of Symmetrical Components
7.4 Examples of Unbalanced Short‐Circuits
8 Short‐Circuit Currents
8.1 Introduction
8.2 Fault Types, Causes, and Designations
8.3 Short‐circuit with R–L Network
8.4 Calculation of the Stationary Continuous Short‐circuit
8.5 Calculation of the Settling Process
8.6 Calculation of a Peak Short‐Circuit Current
8.7 Calculation of the Breaking Alternating Current
8.8 Near‐Generator Three‐Phase Short‐circuit
8.9 Calculation of the Initial Short‐Circuit Alternating Current
8.10 Short‐Circuit Power
8.11 Calculation of Short‐Circuit Currents in Meshed Networks
8.12 The Equivalent Voltage Source Method
8.13 Short‐Circuit Impedances of Electrical Equipment
8.14 Calculation of Short‐Circuit Currents
8.15 Thermal and Dynamic Short‐circuit Strength
8.16 Examples for the Calculation of Short‐Circuit Currents
9 Relays
9.1 Terms and Definitions
9.2 Introduction
9.3 Requirements
9.4 Protective Devices for Electric Networks
9.5 Type of Relays
9.6 Selective Protection Concepts
9.7 Overcurrent Protection
9.8 Reserve Protection for IMT Relays with Time Staggering
9.9 Overcurrent Protection with Direction
9.10 Dependent Overcurrent Time Protection (DMT)
9.11 Differential Relays
9.12 Distance Protection
9.13 Motor Protection
9.14 Busbar Protection
9.15 Saturation of Current Transformers
9.16 Summary
10 Power Flow in Three‐Phase Network
10.1 Terms and Definitions
10.2 Introduction
10.3 Node Procedure
10.4 Simplified Node Procedure
10.5 Newton–Raphson Procedure
11 Substation Earthing
11.1 Terms and Definitions
11.2 Methods of Neutral Earthing
11.3 Examples for the Treatment of the Neutral Point
11.4 Dimensioning of Thermal Strength
11.5 Methods of Calculating Permissible Touch Voltages
11.6 Methods of Calculating Permissible Step Voltages
11.7 Current Injunction in the Ground
11.8 Design of Earthing Systems
11.9 Types of Earth Rods
11.10 Calculation of the Earthing Conductors and Earth Electrodes
11.11 Substation Grounding IEEE Std. 80
11.12 Soil Resistivity Measurement
11.13 Measurement of Resistances and Impedances to Earth
11.14 Example: Calculation of a TR Station
11.15 Example: Earthing Resistance of a Building
11.16 Example: Cross‐Sectional Analysis
11.17 Example: Cross‐Sectional Analysis of the Earthing Conductor
11.18 Example: Grounding Resistance According to IEEE Std. 80
11.19 Example: Comparison of IEEE Std. 80 and EN 50522
11.20 Example of Earthing Drawings and Star Point Treatment of Transformers
11.21 Software for Earthing Calculation
12 Protection Against Electric Shock
12.1 Voltage Ranges
12.2 Protection by Cut‐Off or Warning Messages
13 Equipment for Overcurrent Protection
13.1 Electric Arc
13.2 Low‐Voltage Switchgear
14 Current Carrying Capacity of Conductors and Cables
14.1 Terms and Definitions
14.2 Overload Protection
14.3 Short‐Circuit Protection
14.4 Current Carrying Capacity
14.5 Examples of Current Carrying Capacity
14.6 Examples for the Calculation of Overcurrents
15 Selectivity and Backup Protection
15.1 Selectivity
15.2 Backup Protection
16 Voltage Drop Calculations
16.1 Consideration of the Voltage Drop of a Line
16.2 Example: Voltage Drop on a 10 kV Line
16.3 Example: Line Parameters of a Line
16.4 Example: Line Parameters of a Line
16.5 Voltage Regulation
16.6 Examples for the Calculation of Voltage Drops
17 Switchgear Combinations
17.1 Terms and Definitions
17.2 Design of the Switchgear
17.3 Proof of Observance of Boundary Overtemperatures
17.4 Power Losses
18 Compensation for Reactive Power
18.1 Terms and Definitions
18.2 Effect of Reactive Power
18.3 Compensation for Transformers
18.4 Compensation for Asynchronous Motors
18.5 Compensation for Discharge Lamps
18.6
c/k
Value
18.7 Resonant Circuits
18.8 Harmonics and Voltage Quality
18.9 Static Compensation for Reactive Power
18.10 Examples of Compensation for Reactive Power
19 Lightning Protection Systems
19.1 Lightning Protection Class
19.2 Exterior Lightning Protection
19.3 Interior Lightning Protection
20 Lighting Systems
20.1 Interior Lighting
20.2 Types of Lighting
20.3 Lighting Calculations
20.4 Planning of Lighting with Data Blocks
20.5 Procedure for Project Planning
20.6 Exterior Lighting
20.7 Low‐Voltage Halogen Lamps
20.8 Safety and Standby Lighting
20.9 Battery Systems
21 Generators
21.1 Generators in Network Operation
21.2 Connecting Parallel to the Network
21.3 Consideration of Power and Torque
21.4 Power Diagram of a Turbo Generator
21.5 Example 1: Polar Wheel Angle Calculation
21.6 Example 2: Calculation of the Power Diagram
22 Transformer
22.1 Introduction
22.2 Core
22.3 Winding
22.4 Constructions
22.5 AC Transformer
22.6 Three‐phase Transformer
22.7 Transformers for Measuring Purposes
22.8 Transformer Efficiency
22.9 Protection of Transformers
22.10 Selection of Transformers
22.11 Calculation of a Continuous Short‐Circuit Current on the NS Side of a Transformer
22.12 Examples of Transformers
23 Asynchronous Motors
23.1 Designs and Types
23.2 Properties Characterizing Asynchronous Motors
23.3 Startup of Asynchronous Motors
23.4 Speed Adjustment
24 Questions About Book
24.1 Characteristics of Electrical Cables
24.2 Dimensioning of Electric Cables
24.3 Voltage Drop and Power Loss
24.4 Protective Measures and Earthing in the Low‐voltage Power Systems
24.5 Short Circuit Calculation
24.6 Switchgear
24.7 Protection Devices
24.8 Electric Machines
References
Index
End User License Agreement
List of Tables
Chapter 2
Table 2.1 Coincidence factors for the main feed‐in.
Table 2.2 Coincidence factors for important consumers.
Table 2.3 Planning values for networks.
Chapter 5
Table 5.1 Acceptable ranges of remuneration.
Chapter 8
Table 8.1 Selection via short‐circuit currents.
Table 8.2 Voltage factor
in accordance with IEC 60909‐0.
Table 8.3 Zero‐sequence resistances of transformers.
Chapter 9
Table 9.1 Values of
and
.
Chapter 11
Table 11.1 Advantages and disadvantages of networks with isolated, free neut...
Table 11.2 Advantages and disadvantages of networks with ground fault compen...
Table 11.3 Short‐circuit current density
(maximum temperature of 200
C).
Table 11.4 Advantages and disadvantages of networks with low‐resistance neut...
Table 11.5 Decrement factors.
Table 11.6 Measurement results.
Chapter 12
Table 12.1 Description of time/current zones.
Table 12.2 Voltage ranges.
Table 12.3 Rated voltages and maximum cut‐off times for TN systems.
Table 12.4 Rated voltages and maximum cut‐off times for TT systems.
Table 12.5 Coincidence factor
.
Table 12.6 Rated voltages and maximum cut‐off times for IT systems (second f...
Table 12.7 Summary of measurement errors and measuring instrument errors.
Table 12.8 Summary of overcurrent protective equipment and loop resistances ...
Chapter 13
Table 13.1 Utilization categories for contactors.
Table 13.2 Current‐limiting classes in
.
Table 13.3 Color coding of fuses.
Table 13.4 Rated current ranges for NH fuse elements.
Table 13.5 Threads of fuses.
Table 13.6 Tripping currents of fuses.
Table 13.7 Determining the position requirements for distribution cabinets.
Chapter 14
Table 14.1 Overload protection equipment, conventional tripping current, and...
Table 14.2 Parameters for the rated short‐circuit current density.
Table 14.3 Factor
.
Table 14.4 Short‐circuit temperatures for cables in
C.
Table 14.5 Short‐circuit temperatures
for overhead lines in °C.
Table 14.6 Planning information for cables and lines.
Table 14.7 Reference installation types A1, A2, B1, B2, C, E, F, and G for c...
Table 14.8 Reference installation types A1, A2, B1, B2, C, E, F, and G for c...
Table 14.9 Loading capacity of cables and lines for permanent installation i...
Table 14.10 Recommended values for the current carrying capacity of cables a...
Table 14.11 Recommended values for the current carrying capacity of cables a...
Table 14.12 Correction factors for grouping of cables and lines with rated l...
Table 14.13 Correction factors for grouping of cables and lines with rated l...
Table 14.14 Correction factors for grouping of multicore cables and lines on...
Table 14.15 Correction factors for spooled lines.
Table 14.16 Correction factors for multicore cables and lines with
.
Table 14.17 Correction factors for deviating ambient temperatures.
Table 14.18 Loading capacity, underground overhead installation, layout of i...
Table 14.19 Loading capacity, underground installation, cable with
.
Table 14.20 Loading capacity, overhead installation, cable with
.
Table 14.21 Correction factors for grouping of overhead lines, single‐core c...
Table 14.22 Correction factors for grouping of overhead lines, multiple‐core...
Table 14.23 Correction factors for underground grouping of cables, ground te...
Table 14.24 Correction factors for deviating ambient temperatures.
Table 14.25 Correction factors for multicore cables with conductor cross sec...
Table 14.26 Continuous current carrying capacity of overhead lines.
Table 14.27 Continuous current carrying capacity of overhead lines.
Table 14.28 Continuous current carrying capacity of busbars.
Chapter 16
Table 16.1 Cases.
Table 16.2 Maximum permissible voltage drop according to technical condition...
Table 16.3 Maximum line lengths with source impedances up to the meter mount...
Table 16.4 Maximum line lengths with source impedances up to the meter mount...
Table 16.5 Resistance per unit length for (Cu) cable with plastic insulation...
Chapter 17
Table 17.1 Impact factor depending on
and
.
Table 17.2 Design load factor as a function of the number of main circuits.
Chapter 19
Table 19.1 Characteristic of the lightning protection classes.
Table 19.2 Examples for protection classes.
Table 19.3 Down conductors.
Table 19.4 Soil resistivity for different types of soil.
Table 19.5 Values of the coefficients.
Table 19.6 Definition of zones.
Chapter 20
Table 20.1 Ambient temperatures of light fixtures.
Table 20.2 Power consumption in W for fluorescent lamps with low‐loss conven...
Table 20.3 Utilization factors
(
).
Table 20.4 Number of lamps in a room.
Table 20.5 Maximum number of fluorescent lamps.
Table 20.6 Number of discharge lamps per circuit‐breaker.
Table 20.7 Power requirement for a nominal illuminance
= 500 lx.
Table 20.8 Light flux requirement for a nominal illuminance
lx.
Table 20.9 Room data.
Table 20.10 Standard values taken from workspace regulations.
Table 20.11 Data for light fixtures.
Table 20.12 Data for lamps.
Table 20.13 Technical data for lighting systems.
Table 20.14 Requirements for safety and backup lighting according to use of ...
Chapter 22
Table 22.1 Overview of vector groups.
Chapter 23
Table 23.1 Comparison of Dahlander circuits.
Table 23.2 Rated motor values for
.
List of Illustrations
Chapter 1
Figure 1.1 Generation, transmission, and distribution of electric power.
Chapter 2
Figure 2.1 Overview of a power system.
Figure 2.2 Feed‐in and load field.
Figure 2.3 Arrangement of a transformer room.
Figure 2.4 Simple radial system, radial system with changeover connection. (...
Figure 2.5 Radial system in an interconnected network.
Figure 2.6 Principle of low‐voltage (LV) distribution.
Figure 2.7 Low‐voltage concept for the future.
Figure 2.8 Design basis for main lines in residential buildings without elec...
Figure 2.9 Design of a new distribution panel.
Chapter 3
Figure 3.1 Concept of DC low‐voltage electrical installation.
Figure 3.2 Example of electrical installation in TN‐S system.
Figure 3.3 Example of architecture and operating modes of installations.
Chapter 4
Figure 4.1 Energy management in the smart grid networks [6].
Chapter 6
Figure 6.1 Three‐phase synchronous machines.
Figure 6.2 System of three conductors.
Figure 6.3 Four‐wire system.
Figure 6.4 Pointer and line diagrams of star stresses.
Figure 6.5 Voltages of the three‐phase system in pointer representation.
Figure 6.6 Diagram of star and conductor voltages.
Figure 6.7 Consumer in star connection with neutral conductor.
Figure 6.8 Consumer in star connection with neutral conductor.
Figure 6.9 Three‐phase network in delta connection.
Figure 6.10 Three‐phase network in star connection.
Figure 6.11 Three‐phase consumer.
Figure 6.12 Example circuit.
Figure 6.13 Example circuit.
Chapter 7
Figure 7.1 View of a three‐phase network.
Figure 7.2 Three‐phase symmetrical systems.
Figure 7.3 Unbalanced network operation.
Figure 7.4 View of an asymmetrical system of positive, negative, and zero sy...
Figure 7.5 Symmetrical components.
Figure 7.6 Results of symmetrical components.
Figure 7.7 Symmetrical components.
Chapter 8
Figure 8.1 Behavior of the short‐circuit current over time. (a) Far‐from‐gen...
Figure 8.2 Types of faults. (a) Three‐pole short‐circuit. (b) Two‐pole short...
Figure 8.3 Types of errors.
Figure 8.4 Short‐circuit with
–
network.
Figure 8.5 Short ‐circuit‐current‐switch‐on operations.
Figure 8.6 Short‐circuit current over time.
Figure 8.7 Near‐generator three‐pole short‐circuit.
Figure 8.8 Superposition procedure.
Figure 8.9 Voltage source.
Figure 8.10 Power systems and equivalent circuit diagram of the network. (a)...
Figure 8.11 Equivalent voltage source.
Figure 8.12 Power supply feeder.
Figure 8.13 Synchronous machine.
Figure 8.14 Transformer and its equivalent circuit.
Figure 8.15 Example for the connection of different motors in industrial net...
Figure 8.16 Cables and lines.
Figure 8.17 Impedance correction for generators.
Figure 8.18 Impedance correction for power station transformer.
Figure 8.19 Network and equivalent circuit for a three‐pole short‐circuit cu...
Figure 8.20 Network and equivalent circuit for a single‐pole short‐circuit c...
Figure 8.21 Network and equivalent circuit for a single‐pole short‐circuit w...
Figure 8.22 Loop impedance.
Figure 8.23 Factor
for calculation of the peak short‐circuit current
.
Figure 8.24 Factor
for calculation of the symmetrical breaking current of ...
Figure 8.25 Factor
for calculation of the symmetrical breaking current of ...
Figure 8.26 Factors
and
for calculation of the steady‐state short‐circui...
Figure 8.27 Factors
and
for calculation of the short‐time current.
Figure 8.28 Wiring diagram.
Figure 8.29 Building installation.
Figure 8.30 Power supply feeder.
Figure 8.31 Complex calculation.
Figure 8.32 Calculation with effective and reactive power.
Figure 8.33 System calculation.
Figure 8.34 Short‐circuit currents with impedance corrections.
Figure 8.35 Power system.
Chapter 9
Figure 9.1 Structure of a distribution level and relays installation.
Figure 9.2 Built‐in protection functions [45].
Figure 9.3 Overcurrent protection.
Figure 9.4 Examples for IMT.
Figure 9.5 Principal circuit diagram of definite time relays protection.
Figure 9.6 Directional overcurrent protection: general settings.
Figure 9.7 Overcurrent protection with direction [3].
Figure 9.8 Dependent overcurrent protection [45].
Figure 9.9 Principal circuit diagram of line differential protection.
Figure 9.10 Principle of differential protection.
Figure 9.11 Principle schemes of distance protection.
Figure 9.12 Distance protection characteristics, general settings.
Figure 9.13 Characteristics of the relay zones [45].
Figure 9.14 Distance protection.
Figure 9.15 Busbar protection [45].
Figure 9.16 Busbar protection [45].
Chapter 10
Figure 10.1 Power flow network nodes.
Figure 10.2 Example network for simplified node procedure: Load nodes 1, 2, ...
Figure 10.3 Example network for the simplified node method: Load nodes 1, 2,...
Chapter 11
Figure 11.1 Terms and definitions.
Figure 11.2 Terms and definitions.
Figure 11.3 Prospective touch voltage
, ground voltage
, Step voltage
[1...
Figure 11.4 Partial short‐circuit currents in the event of an earth short‐ci...
Figure 11.5 Partial short‐circuit currents in the event of an earth short‐ci...
Figure 11.6 Relevant currents for the design of earthing systems.
Figure 11.7 Isolated earthing.
Figure 11.8 Resonant earthing.
Figure 11.9 Solid (low impedance) earthing.
Figure 11.10 Solid (low impedance) earthing.
Figure 11.11 Touch voltage
.
Figure 11.12 Permissible touch voltage [12].
Figure 11.13 Half sphere with tension funnel.
Figure 11.14 Design of earthing systems [12].
Figure 11.15 Types of earth rods. (a) Deep rods. (b) Earthing strip. (c) Mes...
Figure 11.16 Fibrillation current against body weight for different animals ...
Figure 11.17 Body current–time characteristic.
Figure 11.18 Wenner four‐pin method.
Figure 11.19 Measurement of earth resistance.
Figure 11.20 Distribution transformer.
Figure 11.21 Design of the earthing system.
Figure 11.22 Short‐circuit current density
for earthing conductors and ear...
Figure 11.23 Substation.
Figure 11.24 Example of earthing of a transformer station.
Figure 11.25 Example of a TN system installation.
Figure 11.26 Example of a sub‐distribution.
Figure 11.27 Example of a sub‐distribution with 20
earthing resistance.
Figure 11.28 Example of an one‐phase short‐circuit directly earthed.
Figure 11.29 Example of a sub‐distribution with neutral point isolation.
Figure 11.30 Protection of the system.
Figure 11.31 Earth surface potential distribution with static model and equi...
Figure 11.32 Earth surface potential distribution with rigorous model (color...
Figure 11.33 Application limits for model based on equipotential assumption....
Figure 11.34 Measured apparent soil resistivity and resistance as a function...
Figure 11.35 Soil resistivity measured values and four‐layers soil model....
Figure 11.36 Grounding system layout and injection point of the current to e...
Figure 11.37 Leakage current distribution.
Figure 11.38 Potential distribution.
Figure 11.39 Earth surface potential distribution.
Figure 11.40 Touch voltage distribution.
Figure 11.41 Step voltage distribution.
Figure 11.42 Safe areas distribution – IEEE Std. 80‐2013 body weight 70 kg....
Figure 11.43 Safe areas distribution with additional soil covering layer – I...
Figure 11.44 Safe areas distribution with additional soil covering layer – I...
Figure 11.45 Safe areas distribution with additional soil covering layer – E...
Chapter 12
Figure 12.1 Conventional time/current zones of AC currents.
Figure 12.2 Circuitry of a TN system and its equivalent circuit diagram.
Figure 12.3 Circuitry of a TT system and its equivalent circuit diagram.
Figure 12.4 Circuitry of an IT system and its Equivalent circuit diagram.
Figure 12.5 Protective measure with heating unit and electrical outlet.
Figure 12.6 Protective measure for connection line to a house.
Figure 12.7 Protective measure for a TT system.
Chapter 13
Figure 13.1 Origin of the electric arc.
Figure 13.2 Electric arc characteristic.
Figure 13.3 Dynamic characteristic.
Figure 13.4 DC cut‐off.
Figure 13.5 AC cut‐off.
Figure 13.6 Cut‐off for large inductances.
Figure 13.7 Cut‐off of pure resistances.
Figure 13.8 Cut‐off of capacitances.
Figure 13.9 Transient voltage.
Figure 13.10 Switching of an asynchronous three‐phase machine.
Figure 13.11 Protection of a three‐phase asynchronous machine.
Figure 13.12 Time–current characteristics for circuit‐breakers in accordance...
Figure 13.13 Principle of an RCD [57].
Figure 13.14 Planning with RCDs.
Figure 13.15 Design and function of the SLS breaker [46].
Figure 13.16 Tripping characteristic of SLS breakers [46].
Figure 13.17 Current limiting for SLS breakers [58].
Figure 13.18 Comparison of SLS breakers with downstream circuit ‐breakers an...
Figure 13.19 Fuse characteristics from 2 to 1000 A.
Figure 13.20 Fuse characteristics from 4 to 1250 A.
Figure 13.21 Let‐through curves for gG fuses.
Figure 13.22 Time–current characteristics for D0 fuses.
Figure 13.23 Time–current characteristics of power circuit‐breakers [6].
Figure 13.24 Time–current characteristics for fuse links.
Figure 13.25 Let‐through current for HH‐fuses.
Chapter 14
Figure 14.1 Matching of reference values for lines and overload protection e...
Figure 14.2 Conductor forms.
Figure 14.3 Checking the current carrying capacity
Figure 14.4 Checking the current carrying capacity.
Figure 14.5 Protection of cables in parallel.
Figure 14.6 Determination of line length for a boiler.
Figure 14.7 Apartment building with a central meter mounting board.
Figure 14.8 Determination of overload and short‐circuit currents.
Figure 14.9 Example of overload protection.
Figure 14.10 Short‐circuit strength of a line.
Figure 14.11 Terminal diagram for protective equipment.
Figure 14.12 Coordination of overcurrent protection equipment characteristic...
Figure 14.13 Cut‐off currents of protective equipment.
Chapter 15
Figure 15.1 Tripping characteristics of
low voltage fuses
(
NH
) (a) and power...
Figure 15.2 Time selectivity of two power circuit breakers in series [47].
Figure 15.3 Selectivity in the overload region: Fuse upstream from power Cir...
Figure 15.4 Selectivity in the short‐circuit region: Fuse upstream from powe...
Figure 15.5 Selectivity in the overload region: Power circuit breaker upstre...
Figure 15.6 Selectivity in the short‐circuit region: Power circuit breaker u...
Figure 15.7 Current selectivity for two power circuit‐breakers in series [47...
Figure 15.8 Selectivity in a system with two transformers [47].
Figure 15.9 Evaluation of a system with fuses.
Figure 15.10 Time–current characteristics for fuses.
Figure 15.11 Current form for breaking a short‐circuit.
Figure 15.12 Evaluation of a system with power circuit‐breakers.
Figure 15.13 Time–current characteristics for power circuit breakers.
Figure 15.14 Back‐up protection in a system.
Figure 15.15 Selectivity and backup protection for a system with power circu...
Chapter 16
Figure 16.1 Voltage drop calculation with (a) equivalent circuit diagram, (b...
Figure 16.2 Schematic of the network.
Figure 16.3 Voltage drop for a DC system.
Figure 16.4 Voltage drop for an AC system.
Figure 16.5 Voltage drop for a three‐phase system.
Chapter 17
Figure 17.1 Construction of a switchgear.
Figure 17.2 Definitions of short‐circuit currents.
Chapter 18
Figure 18.1 Equivalent circuit diagram of a network with different loading. ...
Figure 18.2 Relation between current, voltage, and power for (a) a resistive...
Figure 18.3 Current and power phasors in networks. (a) Current triangle. (b)...
Figure 18.4 Power triangle with compensation. (a) Partial compensation. (b) ...
Figure 18.5 Series resonant circuit and equivalent circuit diagram.
Figure 18.6 Resonance curve for a series resonant circuit.
Figure 18.7 Parallel resonant circuit.
Figure 18.8 Resonance curve for a parallel resonant circuit.
Figure 18.9 Harmonics.
Figure 18.10 Nonchoked compensation system.
Figure 18.11 Impedance characteristic of a nonchoked network.
Figure 18.12 Compensation system with
choking.
Figure 18.13 Impedance characteristic of a choked network.
Figure 18.14 Series resonant filter circuits.
Figure 18.15 Frequency‐impedance characteristic.
Figure 18.16 Thyristor‐switched capacitances.
Figure 18.17 Thyristor‐controlled inductances.
Figure 18.18 Capacitances in series.
Chapter 19
Figure 19.1 Ground‐to‐electrode potential and voltages for grounding electro...
Figure 19.2 Shielding angle.
Figure 19.3 Exterior lightning protection.
Figure 19.4 Air terminals.
Figure 19.5 Air terminal – mesh.
Figure 19.6 Air terminal with protected area.
Figure 19.7 Air terminal – lightning rod with protected area up to maximum 3...
Figure 19.8 Air terminal – lightning rod with protected area greater than 30...
Figure 19.9 Air terminal – roof superstructures of electrically conductive m...
Figure 19.10 Air terminal for smaller roof superstructures.
Figure 19.11 Arrangement of down conductors.
Figure 19.12 Down conductor in accordance with IEC 1024‐1, Part 1, Section 5...
Figure 19.13 Down conductor in accordance with IEC 1024‐1, Part 1, Section 5...
Figure 19.14 Surface ground electrode.
Figure 19.15 Buried ground electrode.
Figure 19.16 Ground resistance for buried ground electrodes.
Figure 19.17 Enclosed ring ground electrode.
Figure 19.18 Concrete‐footing ground electrode.
Figure 19.19 Ground resistance for steel strip and steel bar ground electrod...
Figure 19.20 Minimum length of a ground electrode.
Figure 19.21 Layout of the building.
Figure 19.22 Exposure of installations to a lightning protection system with...
Figure 19.23 Antenna installed on a roof.
Figure 19.24 (a) Window antenna. (b) Equipotential bonding of antennas.
Figure 19.25 Drawing of an exterior lightning protection system.
Figure 19.26 Lightning protection zones.
Figure 19.27 Interior lightning protection.
Figure 19.28 Installation locations for overvoltage arresters.
Figure 19.29 TN system with overvoltage arresters.
Figure 19.30 TN system with overvoltage arresters.
Figure 19.31 TT system with overvoltage arresters.
Figure 19.32 IT system with overvoltage arresters.
Figure 19.33 IT system with overvoltage arresters.
Figure 19.34 Heavy current system, treatment of active lines at the interfac...
Figure 19.35 Telecommunications system, treatment of active lines at the int...
Chapter 20
Figure 20.1 Luminous intensity distribution.
Figure 20.2 Light fixture spacing.
Figure 20.3 Illuminance distribution.
Figure 20.4 Manufacturer's data for light fixtures.
Figure 20.5 Emergency way lighting.
Figure 20.6 Installation of emergency‐symbol lighting.
Figure 20.7 Installation of emergency‐symbol lighting.
Figure 20.8 Installation of safety lighting.
Figure 20.9 Installation of safety lighting.
Figure 20.10 Installation of safety lighting.
Figure 20.11 Central battery system.
Figure 20.12 Central battery system.
Figure 20.13 Installation of lines.
Figure 20.14 Emergency lighting with central battery.
Figure 20.15 Central battery systems.
Figure 20.16 Installation of battery groups and central batteries.
Figure 20.17 Installation of battery groups and central batteries.
Figure 20.18 Installation of lines.
Figure 20.19 Grouped battery systems.
Figure 20.20 Single battery system.
Figure 20.21 Single battery system.
Figure 20.22 Single battery system.
Figure 20.23 Single battery system.
Figure 20.24 Single battery system.
Chapter 21
Figure 21.1 Equivalent circuit diagram of a synchronous generator.
Figure 21.2 Pointer diagram of the synchronous machine.
Figure 21.3 Mode of operation of synchronous generators, (a) Idle speed, (b)...
Figure 21.4 Torque as a function of polar wheel angle.
Figure 21.5 Power diagram of a turbo generator, (1) rated power limit value,...
Chapter 22
Figure 22.1 Flood law.
Figure 22.2 Law of induction.
Figure 22.3 Energy law.
Figure 22.4 Magnetic scattering.
Figure 22.5 Transformer principle.
Figure 22.6 Characteristics of an oil transformer.
Figure 22.7 Structure and characteristics of a cast resin transformer.
Figure 22.8 AC‐transformer.
Figure 22.9 Complete equivalent circuit diagram of the transformer.
Figure 22.10 Transformer.
Figure 22.11 Transformer short‐circuit.
Figure 22.12 Load of the transformer.
Figure 22.13 Winding arrangement of the three‐phase transformer.
Figure 22.14 Windings circuits.
Figure 22.15 Circuit groups.
Figure 22.16 Symmetrical and asymmetrical load of the transformer.
Figure 22.17 Connection of transformers.
Figure 22.18 Current transformer. (a) Block diagram. (b) Equivalent circuit ...
Figure 22.19 Voltage transformer.
Figure 22.20 Transformer.
Figure 22.21 Rating data of transformers.
Figure 22.22 Rating data of transformers.
Chapter 23
Figure 23.1 Overview of an ASM (stator and rotor).
Figure 23.2 Equivalent circuit diagram of the asynchronous machine.
Figure 23.3 Motor and generator operation. (a) Network operation. (b) Emerge...
Figure 23.4 Speed–torque characteristics.
Figure 23.5 Load characteristics.
Figure 23.6 Direct switch‐on. (a) Fuses with motor protective relay. (b) Fus...
Figure 23.7 Pole changing with a winding, two speeds, one direction of rotat...
Figure 23.8 Typical current and torque characteristics.
Figure 23.9 Star delta switch with star contactor, delta contactor, and netw...
Figure 23.10 Current and torque for star delta startup.
Figure 23.11 Arrangement of the network contactor (a) in the motor line, (b)...
Figure 23.12 Arrangement of the contactors in the delta connection.
Figure 23.13 Two separate windings Y/Y.
Figure 23.14 Thermistor motor protection.
Figure 23.15 Comparison of startup procedures.
Figure 23.16 Calculation for a motor with operating modes.
Guide
Cover
Table of Contents
Title Page
Copyright
Preface
Acknowledgments
Symbols
Abbreviations
Begin Reading
References
Index
Wiley End User License Agreement
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Analysis and Design of Electrical Power Systems
A Practical Guide and Commentary on NEC and IEC 60364
Ismail Kasikci
Author
Prof. Ismail KasikciBiberach University of Applied SciencesInstitut für Gebäude‐ undEnergiesystemeKarlstraße 1188400 BiberachGermany
Cover Images: Photograph by Ismail Kasikci, High Voltage icon © OGdesign/Shutterstock
All books published by WILEY‐VCH are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate.
Library of Congress Card No.: applied for
British Library Cataloguing‐in‐Publication DataA catalogue record for this book is available from the British Library.
Bibliographic information published by the Deutsche NationalbibliothekThe Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at <http://dnb.d-nb.de>.
© 2021 WILEY‐VCH GmbH, Boschstr. 12, 69469 Weinheim, Germany
All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.
Print ISBN: 978‐3‐527‐34137‐5ePDF ISBN: 978‐3‐527‐80340‐8ePub ISBN: 978‐3‐527‐80343‐9oBook ISBN: 978‐3‐527‐80342‐2
Preface
For the design, calculation, dimensioning, and evaluation of an electrical power system, the electrical engineer and technician need not only comprehensive theoretical knowledge but also a reference book to make his work easier. This book is intended to fulfill this task.
This book is a follow‐up to “Analysis and Design of Low‐Voltage Power Systems”, published in 2004, and contains didactical improvements and new topics such as power flow, generators, earthing in electrical networks, and relays. Each topic has been written in such a way that the readers can accomplish their tasks with the help of this book without much effort.
Many practical examples, tables, diagrams, and a comprehensive collection of literature make the compendium a complete tool. Planning values and equations required for the calculation process can be extracted from the numerous tables and diagrams. The book is well suited for teaching as well as for practical use. Special emphasis has been placed on deepening the theory, practice, and standards.
For this reason, the present book, intended as a help for the planning engineer in the solution of problems in electrical networks, also presents a detailed discussion of the current situation in regard to standards.
Following the theoretical part and the discussion of regulations and standards, a wide range of examples taken largely from practice is worked out fully.
The readers will be systematically familiarized with the structure, design, behavior, protection, calculation, planning, and design of electrical networks and switchgear. The following questions are covered in this book:
How can I design the electrical system?
Which regulations do I have to observe?
Which calculations do I have to perform?
Which methods/CAD can I use?
Which protective measures do I have to consider?
Which requirements and conditions apply for project planning?
How can persons and animals be protected against electrical shock?
Which operational components shall I select?
Are there special problems with regard to planning?
For calculation, dimensioning, and evaluation of a system, in addition to extensive professional knowledge the planning engineer requires above all CAD experience and a knowledge of all relevant standards and regulations. Due to the great number of standards and their revision in regular intervals and also due to their increasing international harmonization, maintaining this knowledge is becoming more and more difficult.
This book will give engineers, technicians, master electricians, industry professionals, students convincing insights into the immense complexity of electrical power systems and networks and the breadth and depth of power engineering.
It is not possible to present all topics in one book with theory, practice, and standards. Individual topics can still be deepened with the literature given at the end of the book.
I wish you much success and enjoy reading this book.
Ismail Kasikci
Weinheim1 July 2021
Acknowledgments
I wish to extend my heartfelt thanks to all my professional colleagues and acquaintances who supported me through their ideas, criticism, and suggestions.
I am especially indebted to Dr. Martin Preuss and Mrs Stefanie Volk 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‐VCH for the excellent cooperation and their support in the publication of this book.
I would like to thank the companies Siemens and ABB for their figures, pictures, and technical documentation. In particular, as a member, I am also indebted to the VDE (Association for Electrical, Electronic and Information Technologies) for their support and release of different kind of tables and data.
Furthermore, I welcome every suggestion, criticism, and idea regarding the use of this book from those who read the book.
Finally, I appreciate the feedbacks from designers, planners, and readers for their useful recommendations and critics.
This book describes the most important theory, practical terms, and definitions with respect to IEC or EN standards and useful examples. This book is structured as follows:
Chapter 01
is an introduction into the power system today.
Chapter 02
gives an overview of electrical power systems.
Chapter 03
describes the scope of DC current installations.
Chapter 04
gives a small introduction into smart grids.
Chapter 05
explains planning and project management briefly.
Chapter 05
deals with three phase alternating current.
Chapter 06
gives an overview of the network forms for low and medium voltage.
Chapter 07
describes the method of symmetrical components.
Chapter 08
explains the type of short‐circuit currents in three‐phase networks
and the meaning, tasks, and origin of DIN EN 60909‐0.
Chapter 09
describes the relays in electrical power systems generally.
Chapter 10
explains the load flow calculation.
Chapter 11
explains the type of neutral point treatment and substation earthing
in high‐voltage power installations.
Chapter 12
presents the protection against electric shock.
Chapter 13
deals with the most important overcurrent protection devices with
the time–current characteristics.
Chapter 14
discusses the current carrying capacity of conductors and cables.
Chapter 15
gives an overview of the selectivity and back‐up protection.
Chapter 16
presents the voltage drop calculations.
Chapter 17
gives a brief overview of the switchgear combinations.
Chapter 18
explains the compensation for reactive power.
Chapter 19
describes lightning protection systems.
Chapter 20
gives a brief overview of lighting systems.
Chapter 21
explains generators briefly.
Chapter 22
describes transformers.
Chapter 23
presents low voltage motors.
Chapter 24
asks some questions of each topic.
Symbols
center‐to‐center distance between bus bars, costs of electrical energy,
room length, center‐to‐center distance between conductors,
near‐to‐generator short‐circuit
utilization factor for motors
surface area of walls and ceiling
acquisition price, floor area of room, air intake, and exhaust opening,
initial value of DC component
area of circle
effective cooling area of housing, equivalent collecting area of
stand‐alone structure
individual surface areas of external side of housing
voltage factor
voltage factor, temperature distribution factor, specific heat capacity of
conducting material, smallest power step
phase capacitance
Environmental coefficient
'
ground capacitance
capacitor power
rated power
separation distance
light intensity
average light intensity
rated light intensity
stator frequency
rotor frequency
network frequency
electrodynamic force between conductors
coincidence factor
moment of inertia
height difference, distance between lighting elements
and evaluation level
magnetic field strength, height of housing
decaying DC current component
peak short‐circuit current
current, light intensity
no‐load current
rated short time current
starting current of motor
rated current for motors in a group
initial symmetrical short‐circuit current
cutoff current of overcurrent protective equipment
starting current
leakage current
rated differential current of RCD
fault current (smallest short‐circuit current)
ratio of starting current to rated current
for motor
nominal current
current setting
magnetic current setting
single‐pole short‐circuit current
two‐pole short‐circuit current
three‐pole short‐circuit current
two‐pole short‐circuit with contact to ground
double ground fault short‐circuit current
steady state short‐circuit current
thermal short‐circuit current
load current
rated current of protective equipment
permissible current loading of cable or conductor
rated current
current for delta connection
current for star connection
large test current
initial symmetrical short‐circuit current
mass moment of inertia of load
rated short‐time current density
housing constant, material factor, or specific conductivity
factor, transformation ratio of transformer, material coefficient,
correction factor for operating conditions
1.06 for oil transformers, 1.2 for resin‐encapsulated transformer
costs of work
current distribution coefficient, dependent on
geometrical arrangement
power costs
depends on material of isolation path
depends on lightning protection class
costs of a light fixture, capacity costs for amortization
and interest
costs of installation and installation material
price of a lamp
costs of replacing a lamp
annual costs
proportionate acquisition costs
operating costs resulting from no‐load and short‐circuit losses
maintenance costs
heat transfer coefficient
length
length of horizontal grounding electrode
length of vertical grounding electrode
minimum length of grounding electrode
decaying DC component, thermal effect of DC component
with three‐phase AC current and
single‐phase AC current
motor torque
motor torque for direct startup
motor torque for star‐delta startup
load torque (counter‐torque)
load breakaway torque
rated torque
pull‐up torque
accelerating torque
pull‐up torque
breakdown torque
load moment relative to motor shaft
speed of rotation, calculated number of lighting
elements, thermal effect of AC current component with
three‐pole short‐circuit, number of internal horizontal
partitions, number of transformers in parallel, decaying
AC current component, amortization time in years,
number of loads
total number of lamps
number of lamps per lighting element
synchronous speed of rotation
speed of rotation of motor
speed of rotation of load
number of windings
permissible number of critical lightning strikes
strike frequency of the structural installation
lightning density
rate of interest
rated power
transformer power loss, control gear power loss
effective power, effective power loss of
operational equipment installed in housing,
power consumption of one lamp + control gear
lamp power
Short‐circuit losses
power requirement
installed power
power input
power output
output
no‐load losses
equipment power losses
core losses
load losses
rated power of motor
factor for the calculation of breaking currents
of asynchronous motors
reactive power
dissipated losses
losses dissipated through walls and ceiling
proportion in natural air stream
proportion through walls and ceiling
proportion in forced air stream
no‐load reactive power of transformer
average radius, percent capital costs from
interest and amortization
sum of resistances of grounding electrode and
protective conductor
relative effective resistance of a conductor
grounding resistance
conductor resistance
pure resistance, equivalent resistance, costs of cleaning
per light and per year
ohmic, inductive resistance of control gear network
ohmic, inductive resistance of transformer
ohmic, inductive resistance of network
ohmic, inductive no‐load resistance of transformer
ohmic, inductive no‐load resistance of network
resistance of generator
slip, protection ratio
apparent power, cross section of conductor
short‐circuit power
rated power of individual transformer
load starting capability
sum of rated effective powers
sum of rated apparent powers
initial symmetrical short‐circuit apparent power
no‐load apparent power of transformer
time
cutoff time of overcurrent protection equipment
permissible cutoff time
economic life of lamp
yearly time in use
cutoff time
operating time in years
starting temperature
end temperature
operating time
overtemperature of air in housing, general
overtemperature of air, internal, at half height of housing
overtemperature of air, internal, at three‐quarters
height of housing
overtemperature of air, internal, at upper edge of housing
percent voltage drop
power loss
voltage drop
ground potential rise
touch voltage without potential grading
(on concrete‐footing grounding electrode)
touch voltage without potential control (on concrete‐footing
grounding electrode + potential grading grounding electrode)
line‐to‐ground voltage
Abbreviations
A
aluminum conductor
AC1
non‐inductive or weakly inductive load, resistance furnace
AC2
slipring motors: starting, switching off
AC3
squirrel cage motors: starting, switching off while running
AC4
squirrel cage motors: switching on, breaking by plugging, jogging
ASM
asynchronous motor
B
mine‐type installations
BHKW
block heating power plant
CENELEC
European Committee for Electrotechnical Standards
CW
wave‐shaped concentric conductor
DIN
German Standards Institute
DKE
German Electrotechnical Commission
ED
ON period
EN
European Norm
EPR
ethylene–propylene–rubber insulation
FE
concrete‐footing grounding electrode
G
rubber insulation or generator
HKS
heating, climate, sanitary
HV
high voltage
IEC
International Electrotechnical Commission
L
, L
, L
external conductor
LEMP
lightning electromagnetic pulse
LV
low voltage
LVMD
main low voltage distribution panel
M
motor, switchgear
MDP
main distribution panel
MGT
main grounding terminal
MV
medium voltage
N
neutral conductor
OPE
overcurrent protection equipment
PE
protective conductor
PV
primary voltage (transformer) or harmonics
PVC
polyvinyl chloride insulation
R
semiconductor
RCD
residual current protective device
SEMP
switching electromagnetic pulse
SE
grading grounding electrode
SV
secondary voltage (transformer)
T
transformer
TAB
technical conditions for connection
UMZ
independent maximum time relays or independent
maximum current protection (UMZ relays)
UVV
accident prevention regulations
VBG
accident prevention regulations of the BG
VDE
Union of Electrotechnical, Electronics and
Information Technology
VdS
union of property insurers
VPE
cross‐linked polyethylene insulation
Y
PVC insulation
1Introduction
Energy turnaround, smart grid, smart meters, smart buildings, smart homes, smart cities, renewable energies (RE), digitization, data protection, data security, efficient use of energy, control and regulation with digital technologies, industry 4.0, decentralized energy supply, demand side management (DSM), electric filling stations, and new business models for the electricity market are the new topics, tasks, and challenges we will deal with in the coming years. Figure 1.1 shows the path of electrical energy from the power plant to the consumers.
Electrical networks and switchgear and their planning and project planning are very much affected by this. They must perform various tasks relating to the transmission and distribution of electrical energy safely and economically. Transmission networks are highly meshed. They are used for large‐scale energy transmission, and ensure mutual grid support. Thermal power plants and onshore and offshore wind farms feed into the high‐voltage grids. Only a few major customers are connected to the grid. The distribution networks are meshed. These networks are fed by smaller thermal and industrial power plants and wind farms. Typical followers are customers from the big industry.
The high‐voltage networks are subordinated to the medium‐voltage and low‐voltage networks. Smaller decentralized systems feed into the medium‐voltage and low‐voltage networks. Energy generation plants are based on fossil or renewable fuels such as fuel oil, natural gas, vegetable oil, biodiesel or biogas as well as wind energy plants, photovoltaic (PV) systems, or combined heat and power (CHP) plants. Medium‐voltage networks supply industrial, commercial, offices, and department stores, while low‐voltage networks supply households, agriculture, and small businesses. The legal, political, and social requirements for electrical energy supply are laid down in the Energy Industry Act (EIA). The EIA requires the planning of safe, reliable, inexpensive, and reliable environmentally compatible networks. In addition, the Renewable Energies Act and the Combined Heat and Power Act promote the expansion of renewable energies and combined heat and power generation. Further advances in heat coupling.
In the distribution grids, the increase in regenerative feeds from wind and sun also lead to variable load flows. The wind and solar energy completely covers local consumption at times, so that the grids can be fed back into the grid by means of regenerative braking, thus endangering network security. Today's networks are not designed for feed‐ins from regenerative feed‐ins. The power quality is impaired at the feed‐in node. In addition, the changing load flow directions cause voltage fluctuations that cannot be regulated by the transformers. The use of decentralized energy management systems (DEMS) in the distribution networks will become very important in the future. They coordinate the energy use of the decentralized generation plants with the energy consumption of the consumers and control their energy feed or acceptance. In addition to electricity, a communication network is required that enables the exchange of information between producers, consumers, and storage facilities.
Figure 1.1 Generation, transmission, and distribution of electric power.
In combination with smart metering in buildings (use of intelligent, electric electricity meters), the so‐called Smart Grids (intelligent power grids), which provide load management via bidirectional data communication, are already installed in various plants. Every electrical system must not only satisfy the normal operating condition, but also be designed for faults and must be able to handle both faultless and faulty operating conditions. Therefore, electrical systems must be dimensioned in such a way that neither persons nor material assets are endangered.
The dimensioning, efficiency, and safety of the systems are strongly dependent on the control of short‐circuit currents. With increasing installed capacity, the calculation of short‐circuit currents also gained in importance. A three‐phase system can be temporarily or permanently disturbed by faults, especially short‐circuits, circuit measures, or by consumers. Calculation models and solution algorithms for power generation, transmission, and distribution systems provide a comprehensive tool as a calculation and dimensioning program for the planning, design, analysis, optimization, and management of any power supply network. Owing to the liberalization of the energy markets and in particular the rapid expansion of renewable energies, the requirements for network planning and operational management processes are becoming increasingly complex.
Transformers (with or without medium voltage), generators, and neutral grid feeds are available. A neutral mains supply can be mapped by specifying the impedances, the loop impedance, or the short‐circuit currents. In supply circuits, an individual fuse of parallel cables with several protective devices can optionally be calculated and dimensioned in addition to the fuse protection of parallel cables by a protective device. The selected feeds can be connected to each other via directional or nondirectional couplings. By defining the different operating modes required (e.g. normal operation, emergency operation ), the network supply can be represented in a practical way and included in the calculation.
Sub‐distributors, group switches, busbar trunking systems, busbar trunking systems with central supply, or distributors with replacement impedances are available as distributors. When selecting these elements, certain specifications must also be made with regard to the design, e.g. whether the connecting cable is to be designed as a busbar or cable and which and how many switching devices are to be used. If a cable section is selected, the intended type of installation must also be specified so that the values of the current‐carrying capacity influenced by this are taken into account in the dimensioning. The distributors are always inserted into the graphic on a busbar. This can be the busbar that symbolizes the feed‐in point or the busbar of an already connected distributor or the representation of a busbar string, so that the network can be branched further as a radiation network.
For final circuits, consumers with fixed connections, socket outlet circuits, motors, charging units, capacitors, and equivalent loads are available as elements. These are in turn connected to the busbar of existing sub‐distribution boards or the representation of a busbar line or directly to the busbar symbolizing the feed‐in point. There are also various options for placing these elements in the mesh graphic. These are offered in the selection window specific to the element. Simultaneity factors or utilization factors can also be specified for the different circuits, which are also then taken into account during dimensioning. Once the network structure is completely constructed in this way, the actual calculation and thus the dimensioning and selection of the elements can be initiated.
The results of this dimensioning can be viewed and documented in the various available view variants of the network graphic. In addition to the possibility of individually configuring the labeling of the network graphic, standardized labeling variants (device parameters, load flow/load distribution, short‐circuit load, energy balance) are available, so that all parameters relevant for the network calculation are clearly displayed.
In practice, selectivity verification is often mandatory, e.g. for safety power supply systems. Back‐up protection can also be taken into account when selecting switchgear, i.e. the switching capacity of a downstream switch can be increased by the fact that the upstream switch trips simultaneously and thereby limits the current.
Suitable programs can be used for the design and selection of electrical equipment, calculation of mechanical and thermal short‐circuit resistance, calculation of short‐circuit currents, selectivity and back‐up protection for the selection of overcurrent protection devices, and calculation of the temperature increase in control cabinets.
2Electrical Systems
2.1 High‐Voltage Power Systems
For the distribution and transmission of electric power, standardized voltages according to IEC 60038 are used worldwide. For three‐phase AC applications, two voltage levels are given as follows:
Low voltage
: Up to and including 1 kV AC (or 1500 V DC)
High voltage
: Above 1 kV AC (or 1500 V DC)
