Islanding scheme

Can you explain your application in more detail please.

Is the power plant just a power plant exporting power to the national grid or is this a large power plant powering a large factory site which is also connected to the national grid.

If powering a factory or industrial site, does the power plant have the capacity to meet the site power requirements using the power plant alone with no grid connection (ie- islanded mode).

What country is this in?

This is a captive power plant of 43 MW. This power plant powering to our factory ( total load of a factory is max 22 MW) and also connected to a grid.

This is in INDIA.

Well it shouldn't be too hard to include protection that disconnects your connection to the grid but still leaves your factory connected. You wouldn't want to connect and disconnect too often however as this would put quite a strain on the switchgear (which has a finite switching life).

Additionally as you are using your power plant to export power to the Indian grid you will also need to make sure that you meet any regulatory or contract requirements regarding exported power and power quality. Your power plant may be required to ride through some types of power quality issues on the line to either help stabilize the local grid or prevent excessive capacity drop (ie- you may be penalised if you just stop exporting under certain circumstances).

I doubt if the df/dt relay would respond to voltage dips. But, yes! A vector surge relay would definitely help here. In fact, in many a co-gen power plant (operating in import and/or export modes), Vector Surge Relays have successfully been employed in Grid Islanding Schemes.

We are having same captive power plant and we are using woodward mrp2 relay for grid islanding if we experience voltage dip and directional power related issues from grid side.

we also have REL511 distance prot terminal and REL505 Overcurrent and earthfault prot terminal ABB make for these protections.