Metal clad switchgears of 36kV. I am trying to select a switchgear from 3 different manufacturers Schneider, Areva and ABB, all of them are very good but I need a common denominator to select one of them. It will be helpfull If you could advice me with some ideas. Thank you for your link dbair
iigp2006, you have to determine your own basic switchgear requirement and check against what is offered to you by various manufacturers. You develop your basic switchgear specifications indicating the nominal voltage, continuous current rating, short circuit rating (from calculated three phase short circuit and equivalent fault X/R), your protection, control and metering requirements and of course, the manufacturing standard used, either in IEC or ANSI. With the basic specification plus the metering and protection single line diagram, each of these manufacturer will provide you their data sheets for you to evaluate. Each of these manufacturers can offer you both IEC and ANSI designs.
In most cases, all of these manufacturers will meet your requirements as per manufacturing standard (IEC or ANSI). The common denominator in most cases will be the overall cost (material + delivery) and the delivery time (as dictated by your commisioning date as well as warranty and spare parts availability.
It is not proper to compare each one of them as per make since all of them are having common denominators as well in the design and manufacture of these equipment.
Design and set your parameters and check their offered specs.
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Try to get a user contact list of similar swgr installed from each vendor. Then talk to the maintenance people if possible.
All three can meet minimum specs but workability can vary widely. Also, try to get a factory visit if you can.
Don't underestimate the value of local support and service. If one or more of them are under represented in your area, it can get very expensive down the road to keep flying in technicians. Just out of curiosity, any reason why Siemens is not on your short list?
I don't know if these are 'apart from the obvious' or not, but here are a few, anyway...
1. Interruption medium: Gas or Vacuum? What's the state of the art? What gives you the interrupting ratings that you need. Do all three on your list of suppliers offer both?
2. Insulation medium: gas or air?
3. The answers from (1) & (2) lead to maintenance and monitoring. Does the customer deserve the added grief of gas monitoring and topping off? Also, life expectancy and actual or simulated aging of the interrupters would most likely be the customer's No.1 question.
4. Space. How much room do you have? Have you drawn your oneline and added all necessary magnetics to achieve your protection and metering goals and asked the three manufacturers for their layout?. This is very important because brand 'A' for example is limited to say six CT's per breaker, wheras brand 'B, can install twelve. The same applies for PT's. The differences in size must be accounted for in your real estate.
5. Further to your oneline, you need to tell the manufacturers where are your cables entering and exiting the equipment top, bottom, side, and have them include that in their layout to see how large the equipment gets.
6. What auxiliary equipment is needed for installing the circuit breakers in place, what auxiliary equipment is required for moving the circuit breakers in the electrical romm? Do the breakers roll in and out on their own, or do you need some attachments? What does the customer prefer? Do you have space for storage of all that equipment?
7. Can the breakers be easily tested via switchgear built-in features, or do you need special equipment? That must be factored in the initial cost.
8. What maneuvering (sp?) is required to erect the equipment: forklifts, cranes, rollers, skates, other? Does your installation offer whatever the suppliers require?
9. How accessible are the instrument compartments for maintenance and troubleshooting? Do you need a six foot ladder to climb in and reach?
10. Are the bus joints in the main circuit and cable terminations easy to insulate? Are they applying removable boots, or do they require taping? Factor that in your installation cost.
11. Who provides the longest terminating distances for your MV cables? Does that match your terminators?
And the list goes on and on. But finally, please be advised that, worldwide, there are other manufacturers than the ones you've listed - some here in the USA.
I totally agree with jraef, it's a big plus factor if the manufacturer have both technical support offices and assembly within your area or at least at adjacent country so you will have the flexibility of getting all the support at negligible cost. I ahd an experience of one of our contractors getting the same stuff from a very distant place because they simply offered very less apart from commercial aspects that they have represented. All they had in the locality was a liason office with a "technical representative" who simply pass on queries like basketball. At the end they had a very tough time of coordinating and the ordering time of some spare parts took some time more than expected. Hence, everything looked nice in paper but in the real world, some hussles exist.
The other aspects as described by iigp2006 dictates that you should fully do your basic designs and consideration and the vendors will try build them.
I can offer you some basic suggestions but you have to provide me the application of your switchgear: Voltage, Type of Load to Feed and whether you are installing this to an existing building or a newly designed substation.
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