JezNZ
Electrical
- Jun 17, 2021
- 74
Hi All,
Been a while since I've posted here!
Currently working on the design-build of a microgrid being the first to meet regenerative certification criteria (105% generation of consumption) in the locale I am.
The microgrid will operate both grid-connected and island-mode and is IBR HEAVY (Solar + BESS). So naturally I have the problem of protection (in)sensitivity to low fault currents in island mode.
It looks like I will be headed down the path of zone-based differential protection for MV components, however for LV it is a lot trickier to find a cost justifiable solution.
Sadly the IEEE draft guide on Microgrid Protection doesn't help much other than to suggest running studies (of course??), but there are some good papers floating around. One the most promising options suggests using "adaptive setting circuit breakers" - now I assume in principle this means you have a group of settings for grid-mode and another group for island-mode - easy!
BUT - does such a product actually exist? Commercially? In my mind I am thinking of cost efficient protection like MCCBs or Power Circuit Breakers whose microprocessor trip units can be toggled between two settings groups?
Or is this just implying I need to put in high end relaying and CTs etc and have custom logic etc? Or go old school and CTs and overload relays with shunt trips and selectable relays in different modes - neither of which are paths I would like to go down.
Will take other thoughts on creative solutions people out there have come up with!
Been a while since I've posted here!
Currently working on the design-build of a microgrid being the first to meet regenerative certification criteria (105% generation of consumption) in the locale I am.
The microgrid will operate both grid-connected and island-mode and is IBR HEAVY (Solar + BESS). So naturally I have the problem of protection (in)sensitivity to low fault currents in island mode.
It looks like I will be headed down the path of zone-based differential protection for MV components, however for LV it is a lot trickier to find a cost justifiable solution.
Sadly the IEEE draft guide on Microgrid Protection doesn't help much other than to suggest running studies (of course??), but there are some good papers floating around. One the most promising options suggests using "adaptive setting circuit breakers" - now I assume in principle this means you have a group of settings for grid-mode and another group for island-mode - easy!
BUT - does such a product actually exist? Commercially? In my mind I am thinking of cost efficient protection like MCCBs or Power Circuit Breakers whose microprocessor trip units can be toggled between two settings groups?
Or is this just implying I need to put in high end relaying and CTs etc and have custom logic etc? Or go old school and CTs and overload relays with shunt trips and selectable relays in different modes - neither of which are paths I would like to go down.
Will take other thoughts on creative solutions people out there have come up with!