1.1.1 Plant Design Procedure
Plant design is a joint effort by multiple engineering disciplines: process, mechanical, civil, electrical, architectural, structural, estimating, scheduling, procurement, document controls, and project management. Every department is doing its work in strict coordination with others to insure everyone is “on the same page” and that nothing falls “between the cracks.” Lead engineers of all the disciplines are on the email circulation of everything that is happening on the project to insure all the design decisions and project changes are being communicated and implemented, both “vertically and horizontally” through the project organization chart. Regular meetings are held on a weekly basis to assess the progress, critical path schedule, any design changes, manpower shortfalls, and any delays in design, procurement, fabrication, and installation and their impact on the project schedule. Design options and temporary measures are being reviewed to overcome the delays in the equipment deliveries and/or equipment failures.
1.1.2 Codes and Standards
The publications listed below form a part of this book. Each publication shall be the latest revision and addendum in effect at the time of issue of contract and design specifications, unless noted otherwise.
| ANSI | American National Standards Institute |
| CSA | Canadian Standards Association |
| IEEE | Institute of Electrical and Electronic Engineers |
| IEC | International Electro‐technical Commission |
| ISA | Instrument Society of USA |
| ISO | International Standards Organization |
| NACE | The Worldwide Corrosion Authority |
| NEMA | National Electrical Manufacturer's Association |
| NEC | National Electrical Code |
| NFPA | National Fire Protection Association |
| UL | Underwriters Laboratories of USA |
Standards, codes, and guidelines listed above and referenced in every chapter of this book are widely used by the engineers in the industry, both as directives and guides. When working in another country, the local standards must also be applicable. This book refers to and often presents data courtesy of these engineering standards, which are considered one of the major sources of guidelines and good engineering practices for engineers.
The standards and codes are extremely important. Actually, there are three parts to your success as an experienced engineer:
1 Understanding the applicable standards and knowing how and where to apply them.
2 Referring to the suppliers' equipment catalogs and reviewing the graphs and performance data sheets to determine the proper equipment ratings and supplies for your specific applications.
3 Building experience by field reviews of the equipment performance and its related hardware.
1.2 Project Development
1.2.1 Type of Project
A typical project referred to in this book is an ore‐bearing property, owned by an investor, which according to the exploration figures contains a large ore body of Cu/Zn ore. This can equally be a mining property of coal, silver, and gold, or it may be a brewery batch plant or a large harbor development.
On the power industry side, this may be a hydro development project, for which a catchment area is defined and dammed to create a head and estimate the flow of water that can be controlled from the area. The electrical part of the project, though large, is relatively small in comparison with the huge civil infrastructure required to be built. Utilities typically take ownership of these large projects.
1.2.2 Conceptual Design for Feasibility Study
If the project gets a go ahead by the investment partners, the investors or their bank will provide initial funding to engage an engineering company to investigate the project a bit closer. There are a number of different engagements possible between the owner and the engineer that can be employed. That may be a subject of another book.
The project team with all the engineering disciplines has been given an assignment to develop conceptual drawings and budget estimate. The conceptual design includes plant layouts, load flow diagrams, electrical design criteria for all the electrical activities and equipment, a key one‐line diagram, and a reasonable accurate capital cost estimate to be presented as a “bankable feasibility study.” This document will also serve as a basis for the future detail engineering design to build the project, should the project proceed further.
The design calculations in this conceptual study will use the system and equipment characteristics from previous projects similar to this one to generate the design parameters for the new project. The budget estimate is obtained from the various budget quotations, previous projects, and earlier work done in the country of the project with their labor rates.
During this three to six months of engineering phase, some major long lead mechanical and electrical equipment may be ordered on the basis of a possibility of cancelling the orders if things don't “pan out.” The electrical lead equipment may include the main transformers and HV switching equipment.
The flow diagrams show the flow of the ore, through the various plant processes, including additions of other ingredients: water, heat, and fuel to process it and take it to the final product. In this case, the final products are bars of Cu and Zn. Where there is Cu, there is a chance of minor percentage of gold, while silver is never far off from a deposit of Zn.
From the electrical design perspective, design criteria, major cable routing, and one‐line diagrams will define the shape of the plant power distribution and other aspects of the electrical equipment and plant operation.
1.2.3 Detailed Design
Detail design will follow the conceptual phase. This “detailed” phase may last anywhere from 9 to 18 months for an industrial plant or two to four years for a power plant, depending on the type of plant. The conceptual drawings will be reworked and expanded. Procurement phase will commence by preparing the purchase specifications to specify equipment performance requirements and also to make the interface diagrams to tie up with the related mechanical equipment. Often, the electrical design may have to wait a while for the mechanical design to near its completion and their suppliers' drawings are in hands to determine the electrical ratings and the interfacing connections needed.
The first effort will be to update the electrical plant design criteria and the key one‐line diagram from the conceptual design phase. These two items are your two big pictures, and the foundations for everything else you plan to build on.
System studies: The detailed design will present final one‐line diagrams with the actual impedances and equipment characteristics. It will use the data based on the results from power system studies: load flows, motor start, voltage drops, phase and ground short circuits, arc flash, insulation coordination, and step and touch potential. The studies will determine