Arc Guard Equipment or Transformer Differential Protection
Arc Guard Equipment or Transformer Differential Protection
(OP)
We have calculated some pretty high incident energy levels on our 440V main switchboards.
Looking to mitigate the arc flash hazard by either implementing arc guard equipment (light and current sensing) or alternatively considering fitting transformer differential protection on the MV/LV transformer.
What are the typical trip times that can be expected with each of these systems?
Looking to mitigate the arc flash hazard by either implementing arc guard equipment (light and current sensing) or alternatively considering fitting transformer differential protection on the MV/LV transformer.
What are the typical trip times that can be expected with each of these systems?






RE: Arc Guard Equipment or Transformer Differential Protection
Transformer differential protection is for faults internal to the transformer. Faults on the secondary switchboards that which are the arc flash concern, will not be seen by the diff. protection.
Rafiq Bulsara
http://www.srengineersct.com
RE: Arc Guard Equipment or Transformer Differential Protection
The transformer secondary up to the main breaker is harder, we usually out a mini VCB in the MV switch where the fuses usually go with relays from the secondary side of the transformer.
Of couse most plants have just gone to remote racking and switching so they can operate and rack all thier breakers wirelessly, much easier and cheaper solution if you have several substations.
I handle all 3 of these solutions everyday, mitigation is my job.
-Scott (Zog)
www.cbsnuclear.com
RE: Arc Guard Equipment or Transformer Differential Protection
If we adopt this method for the rest of the switchboard we intend to fit maintenance switch to reduce protection settings.
Alternative would be to use arc guard for the whole switchboard.
RE: Arc Guard Equipment or Transformer Differential Protection
Do not confuse the transformer diff protection with arc guard equipment or even bus differential protection.
If you are really concerned with personal safety, design the system with a bypass or redundancy so that you can shut down a gear for maintenance without interrupting service to loads. Second choice may be the arc guard.
Rafiq Bulsara
http://www.srengineersct.com
RE: Arc Guard Equipment or Transformer Differential Protection
RE: Arc Guard Equipment or Transformer Differential Protection
The optical systems promise faster response, but there are possible issues with retrofit of optical sensors on existing equipment.
RE: Arc Guard Equipment or Transformer Differential Protection
RE: Arc Guard Equipment or Transformer Differential Protection
I would like to hear what kind of issues there are. As far as I know, retrofit of optical sensors is rather easy. Optical systems (often combined with instantaneous overcurrent) are de facto standard in some countries.
RE: Arc Guard Equipment or Transformer Differential Protection
When provided as part of new equipment, the manufacturer presumably has tested the installation and is assuming responsibility for the location and quantity of sensors. In a retrofit, it isn't as clear cut.