2.3 Site Conditions 2.3.1 Source of Power 2.3.2 Ambient Derating Factors 2.3.3 Reliability Criteria
2.4 Connection to Power Utility 2.4.1 Source Impedance 2.4.2 Line Conductor 2.4.3 HV Circuit Breaker Fault Interrupting 2.4.4 Double or Single Incomer Connection 2.4.5 Utility Generating Capacity 2.4.6 Firm Capacity 2.4.7 Line Protection 2.4.8 Lightning
2.6 Load Site Placement 2.6.1 Crushing 2.6.2 Grinding and Conveying
2.7 The Key One‐Line Diagram 2.7.1 Load Investigation 2.7.2 Connected Load – Operating Load 2.7.3 Voltage Level Selection 2.7.4 Switchgear Breaker Ratings 2.7.5 Single Incomer Substation for a Small Plant 2.7.6 13.8 or 33 kV Switchgear for a Larger Plant 2.7.7 Transformer Connections: Cable, Cable Bus, or Bus Duct? 2.7.8 Medium Voltage Switchgear and Controllers (4.16 kV) 2.7.9 Low Voltage Service Voltage 2.7.10 Bus Tie Breaker Switching 2.7.11 Plant Transformation 2.7.12 Voltage Regulation 2.7.13 Overhead Distribution Lines
2.8 Transformer System Grounding 2.8.1 Transmission Level 2.8.2 MV Systems 2.8.3 LV Systems 2.8.4 Generator Neutrals
2.9 Transformer Winding Configurations and Phasing
2.11 Insulation Coordination 2.11.1 Substation Shielding
2.1 One‐Line Diagrams
Designing a Key one‐line diagram is the most important task in the development of an electrical system for a power or an industrial plant. This diagram is a result of the key decisions made by the engineers working on the project. This book devotes significant time in explaining the electrical components, which are fundamental in building the functional electrical one‐line diagram.
The one‐line diagram represents the electrical power distribution formed to suit the technological process for the proposed project (see Chapter 1). The electrical engineers must focus on acquiring information on the type of process, load magnitude, load centers, quality and availability of power, power loss tolerance, and required plant reliability.
The key one‐line diagram prepared at the initial stage of design will be conceptual in nature. It will encompass the other one‐line diagrams for the specific parts of the plant. It will serve for discussions, cost estimates, and to offer the other design team engineers a basis for their equipment selections. Figure 2.1 is not a “key” diagram, but a part of a plant one line diagram.
The design procedure in this chapter is described in light detail to arouse interest of the electrical engineers in the design and operation of electrical systems for industrial manufacturing and power plants. More clarifying details related to the specific equipment specifications, applications, and reasons for their selection can be found in the chapters that follow.
2.1.1 What Is the One‐Line Diagram, or Single‐Line Diagram?
Mechanical engineers have their “flow diagrams.” Electrical engineers have their single‐line diagrams showing the electrical power flows and plant overall integration. As the name implies, it is the principal electrical diagram or our big picture of the plant or specific part of the plant, whereby the three phases are represented in a simplified single‐line form. The diagrams show all the major transformers, loads, circuit breakers, and cables or line connections, including the ratings: kW (HP), MVA, V, A, AWG (mm2), leading to the major plant equipment. The key diagram includes references to the partial more detailed one‐line diagrams for the specific process areas. One medium size industrial plant may have 20 individual one‐line diagrams starting from the key one‐line diagram down to the individual MCC 480 V (400 V) diagrams.
