Expansion type bus connectors in Substations

[basilasq1]

Hi everyone,

I have a question about bus connectors used in high voltage substations. There are mainly 3 types; fixed connectors, expansion and slide connectors. Whereas some connectors manufacturers use the term expansion and slide interchangeably, is there really any difference between them as some station drawings clearly differentiate both of them.

Thanks!

 

[rterickson]

Expansion and slide do not mean the same thing. A slide connector supports the bus but allows it to slip freely while an expansion connector is analogous to a spring.

Because long sections of rigid bus will expand and contract with changes in temperature, your rigid bus design must allow the bus to move thus avoiding damage. A single section of bus must not be fixed at both ends. If one end is fixed, the other end must be a slide or expansion connection, depending on what type of bus or equipment you are connecting to.

The most common use of an expansion connector is when you have a bus section connection two disconnect switches. One end is fixed, but the other end must be allowed to expand and contract. Slip connectors are most often used on bus supports at the end of a bus section.

 

[basilasq1]

Thanks alot that was very helpful.

A closer look at both connectors shows that sliding connectors usually have a ring to enable tubular bus to slide freely whereas expansion connectors have flexible wire strands to ensure electrical connections as distinct tubular sections expand/contract.

 

[stevenal]

You might want to be careful using the word "connector" since the slip style bus supports you are speaking of are not intended to provide electrical connections.

I would not use slip supports only at bus ends. Any bus run should be fixed at one location only with all other supports allowed to slip.

 

[tinfoil]

I would tend to call the widget intended to hold the bus in place a 'clamp' whereas a widget intended to electrically join two or more components together is a 'connector'.

For each section of rigid bus, our practice is to use a single fixed clamp, with all of the rest are 'sliding' clamps. Where practicable, the fixed clamp is placed as close to the 'middle' of the bus section as possible, to minimize 'worst-case' thermal displacements.

It is important to fix that one point, as heating/cooling cycles can actually cause a bus section to 'walk' over time if every connection is a 'slider'.

Lately, we have been using a clever combination clamp unit that can be either fixed or sliding, depending on which orientation the top bit is fastened to the lower, simplifying our ordering and stocking issues.