Hi Gentelmen;

I have been working on a solar pv system (grid-tie) to be installed on a barge. the barge is spplied by two diesel generators. one is 90KW as a main/standby and the second one is a 150KW as a backup generator connected by a transfer switch.

Fueling up the barge is a big trouble since the barge is about 7miles away from the coast and cost them a lot of money. a 36KW DC solar pv sytsem can decrease fuel consumption by 50% . 

My question is , if we look at the standbygenerator as a grid, can a grid-tie pv system work properly with these generators.

Your advice is appriciated.

Sean

Comments

Sean,

If your 90kW generator has a clean and stable frequency/voltage signature then you could definitely use it with a PV inverter. Here are a few of things to consider:

  1. Baseload - You want to offset diesel, but you don't want to push voltage into the genset or make it run at an ineffieciently low speed. With PV coupled, you don't want the genset to run at less than 35% of it's rated output (this varies greatly by brand).
  2. Safety - If your load drops suddenly, you need to have some kind of safety mechanism to prevent backfeed to the genset. Some PV grid tied (GT) inverters are supplied with current transducer (CT) accessories that monitor voltage rise at the genset and current on the electrical panel to regulate their output power. Otherwise, you need to build something with metering and relays.
  3. Storage - You may not want a battery, but depending on your type of load, some amount of battery can really smooth out the system operation.

If you supply more information on your generator and load profile (interval data or plot), we could probably give some estimates on system design.