HERLEC
Switchgear Services

Tel: +27 11 822 6411                                                      

Fax: +27 11 828 3318

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Herlec Switchgear Services

We specialize in refurbishing M.V. switchgear to the clients specification. The panels are stripped completely then sandblasted and powder coated to suit your requirements. We can disassemble and reassemble most makes and models of circuit breakers and ring main units. We also do repairs and maintenance on most circuit breakers. Our wiring team is capable of wiring protection schemes, control panels, circuit breakers and mini sub L.V. cubicles.

We are capable of installing and commissioning of most makes & models of switchgear (indoor or outdoor).

We also specialize in the installation and maintenance of GIS switchgear especially the Alstom WS.

IMPORTANT NEWS - Herlec Switchgear Services and Sergy Petushkov (formally from TAVRIDA SA) have gone into partnership and created a new company SERGILEC with the full blessing from Tavrida. See more >

Retrofit, Replacement or Refurbishment of Switchgear

1) When faced with ageing switchgear that no longer meet your requirements, you are normally faced with these three options : retrofit, replacement or refurbishment of that switchgear.


2) The problems you may encounter are summarized below:


a) SAFETY

Modern switchgear have evolved to a point where it is safer to operate than the old switchgear. The modern trend towards safety and user liability makes this an important criteria.


b) OPERABILITY

Networks are becoming more and more automated. This may require technology far beyond the capability of the old switchgear.


c) MAINTAINABILTY

Availability of skilled personnel may become a problem and prices might be exorbitant.

 

d) AVAILIBILTY OF SPARES

Parts have a limited production life as technology improvements cause them to be superseded. Lack of spares normally result in malfunctions or equipment being beyond repair.


3) Once you have decided you are faced with 3 options:


a) REPLACEMENT

The old switchgear is stripped out and completely replaced with new switchgear.

                 

b) REFURBISHMENT

Here you retain the old switchgear and do an extensive overhaul. Critical parts may be replaced. The main feature is that the old switchgear is not modified.

 

c) RETROFITTING

Retrofitting is the replacement of certain parts of the switchgear. This could be only the circuit breaker, protection & control or certain current carrying parts, but keeping the basic structure or enclosure.



SBV3 Retrofitted switchgear by Herlec Switchgear Services

4) Advantages and Disadvantages. These are listed in the tables on the right below.

5) Testing

With retrofits or refurbishment there arises some questions like – can the switchgear conform to certain specification such as , short circuit , BIL, ability to break faults etc.

There are four possibilities to overcome this problem - type test, extrapolation, calculation, approximation and synthesis


a) Type test

Here one manufactures a prototype and performs the relevant tests. There are limitations such as cost, time constraints, failure and rework and difficulty in obtaining the prototype.

It is only viable if you are retrofitting large quantities so that you can spread the cost.


b) Approximation & Extrapolation

If you have existing data on the circuit breaker that verifies its performance, you could extrapolate that data to the new installation if its important features are not changed eg.

Busbar sizes, contact arrangements and clearance.

One could then state with a degree of certainty that the retrofits performance would be met.


c) Synthesis

If each building block has to be tested individually and then when brought together, the final result could deemed acceptable by virtue of its components.

The uncertainty would be the interfacing, but this may be treated by extrapolation or calculation.

For example if the circuit breaker and the panel had been tested individually then you could say with a degree of certainty that the combination would meet the require performance.


d) Calculation

It could be possible to calculate whether equipment in a retrofit would be able to meet required performance.


SBV3 Retrofitted switchgear

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Important links:

ADVANTAGE

DISADVANTAGE

RETROFIT


Cost effective

Type test

No change of operation

Spares holding

Reduce outage time

Expose next weakest link

Updated critical equipment

Guarantees

ADVANTAGE

DISADVANTAGE

REPLACEMENT


Full type test

Lengthy outages

New equipment

Cost

Conforms to standards

Disposal of old switchgear

Latest protection

Cabling

Guaranteed

Update spares holding

ADVANTAGE

DISADVANTAGE

REFURBISHMENT


No changes to operations

Possible lengthy outage

Cost effective

Remaining life

Retain spares

Hidden defects


Retain outdated switchgear

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Switchgear refurbishing by Herlec Switchgear Services
Switchgear Refurbishing