Specific Electrical Design Requirements for Industrial Buildings

Introduction:

in the previous Topic " Electrical Design Requirements for Industrial Building" I explain the types of industrial building and the general outlines of electrical requirements for these buildings.

today, I will explain in detail the specific Electrical Requirements for Industrial Buildings which must be known for any engineer wants to learn or practice the electrical design engineering.

Industrial Electrical Installation Requirements

 

any designer wants to optimize his design by completely satisfying the individual needs of the building users, and in case of industrial building design , these individual needs will be generally as follows:


1- Workshop and office flexibility:Upgradeability and reorganization, installation of new machines and modification of up to 50% of the workshop areas every year.

2-Production facility availability, continuity of service:In the metalworking industry for example, an unexpected break in production can result in a loss of up to 100 K Euros for each hour of downtime.

3- Time, investment and operating cost control controlling Energy, refurbishment and maintenance costs.


these needs must be satisfied in the following three levels of electrical design which are:

1. General distribution.
2. Sub-distribution.
3. Final distribution.

first : General distribution Level

This design level is decided as a result of discussions between the electrical designer and architecture. The position of the MV/LV substations determines the size of the distribution infrastructure and its cable ways. The quality and integrity of the network supplying the facility govern the type of power supplies (public network, Gen set, uninterrupted power supply, etc.).

The load characteristics (power, continuity of service, sensitivity to the environment, etc.) are the determining factors for:

• The architecture, 
• The type and number of power supplies (network redundancy and conditioning). 

and The specifications of the main switchboards are based on:

• The power and location of the loads, 
• The possible cable ways, 
• Their environment (degrees of IP protection), maintainability and accessibility. 

Second: Sub-distribution Level

This level conditions energy access by means of zones of homogeneous usage. Apart from the power and number of connected devices, the flexibility and safe distribution requirements for each zone should be taken into account.

Third: Final distribution Level

This level applies mainly to the following:

• Workstation and mobile equipment.
• Lighting power supply.

these three levels construct what we called "  Power distribution architecture" which reviewed many times by the designer in order to get it more optimized to ensure that the industrial facility runs smoothly and operates to its maximum potential.

Power distribution architecture 

Each industrial site has its own particular needs and requires a specific type of power distribution architecture to achieve the following principles:

• Flexibility, which is based mainly on the sub-distribution and final distribution design 
• Availability, which is primarily governed by the higher levels of the architecture.
• Cost optimization, which is closely, linked to the location of the MV/LV substations.

but how a power distribution architecture can achieve these principles in industrial buildings?
for answering this question, let us take an example for one part of a power distribution architecture like lighting & power outlets installation system and let us see how it can designed to be flexible, reliable and economical.

lighting & Power Outlets installation system in an industrial facility: (see fig.1)

fig (1): Lighting & Power Outlets Installation
 System in an Industrial Facility

in this example, the lighting installation system will consists of two parts:

1. The fixed part.
2. The mobile part.

First :The fixed part 

The fixed part is supported by the structure of the building (walls, posts) and consists of: 

• (A) Low power busbar trunking to supply power to the workstation zone: quick and easy to install, high load density supply, reliable connections due to prefabrication.

• (B) Cable ways suspended from metal supports shared with the busbar trunking.

• (C) Consolidation points allowing easier connection and greater equipment mobility. The prefabricated copper connections have spare consolidation points allowing them to handle additional communicating devices (PCs, printers, workshop terminals, etc.).

• (D) Multi-functional weatherproof enclosures (IP65 and IK09) to supply power and data to the terminal connected equipment located within their sphere of operation. They are mounted on fixed supports (walls, posts) or mobile supports (industrial poles). They create a network covering the production area to allow power and data to be accessed at any point. 

Second : The mobile part

The mobile part consists of: 

• (E) low-power busbar trunking tap-off units for supplying power to industrial poles, loads or multifunctional weatherproof enclosures.

• (F) Industrial poles to supply workstations with power, data and utilities (compressed air, water, vacuum, oil, etc.). Industrial poles ensure a Quick and easy installation/removal/ relocation, fast connectivity, support for computers, communications terminals or instruments. 

as we see from the design planed above for the lighting & power outlets installation system that it has the following advantages:

• Meets the need for flexibility required by the activities involved, 
• Allows controlling of investment and operating costs. 
• able to adapt easily and quickly to Workstation mobility, 
• able to adapt easily and quickly to an increase in the number of connected devices to be supplied. (the last two points ensure the system availability)

Types of Power distribution architectures in industrial buildings:

The famous Power distribution architectures in industrial buildings will be as follows:

1. "Radial branched" power distribution architecture 
2. "Dual-transformer shared" power supply distribution architecture. 
3. "Multiple-transformer shared" power distribution architecture

First : "Radial branched" power distribution architecture (see fig.2)

fig (2): "Radial branched" power distribution architecture

This power distribution architecture satisfies the standard requirements of all the medium size industrial facilities and ensure the following: 

• Assembly/ conditioning and machine shop flexibility.
• Production facility availability.
• Control over investment and operating costs. 

The electrical design levels in this power distribution architecture will be as follows:

1- General distribution Level:

The main switchboard was placed in the best possible position, according to load-sharing requirements and the constraints imposed by the building.


2- Sub-distribution Level:

in this level, Loads are supplied:

• Directly from the main switchboard in the case of high power loads and/or loads sensitive to electrical disturbances,
• from medium or low-power busbar trunking in the case of homogeneous loads requiring flexibility (reconfiguration, addition of new machines, and so on). 

3- Final distribution Level:

in this level, each final load will be supplied as follows:

• The mobile devices connected via their industrial outlets are supplied from multi-functional weatherproof enclosures. 
• The lighting throughout the workshops is distributed via busbar trunking. 
• Mobile workstations are supplied via industrial poles. 

evaluation of this power distribution architecture:

• This power distribution architecture provides the industrial process with a distributed supply at sub-distribution level , making it easier to connect workshop loads, irrespective of their location. This sub-distribution design is independent of the industrial process design. 

• in This power distribution architecture,the designer can satisfy the high level of availability required by sensitive loads (servers, programmable controllers, etc.) due to its Uninterruptible Power Supply (UPS). 

• It uses mainly factory- built units (busbar trunking and distribution board components) and this achieve the following: 

1. Shorter installation time.
2. Easy deal with design ( specifications, inaccuracies, etc.) , installation (worksite, hazards, etc.) and operating (modification, workshop relocation, etc.).
3. The reliability of the plant is guaranteed.

this power distribution architecture has the following evaluation:

Flexibility	**
Availability	**
Time and Cost Control	**

in the next Topic, I will continue explaining other types of power distribution architecture for Industrial Building. please, keep following.