Equipment
Turbines: (2) Leffel 27, B-4 propeller turbines (145HP each) and (1) Leffel 21-Z Francis turbine (85HP)
Leffel 27, B-4.
Generators: Oemer 100kW Permanent Magnet Generator mounted vertically and directly coupled to the Leffel 27, B-4
Oemer Permanent Magnet Generator. Only half of the chassis is actual generator hard stuff. The remainder is air plenum and cooling fan. This generator is 1/3 the size and 1/2 the weight of a "typical" generator.
Power Electronics and Data:
Results from Leffel 27 B-4, PM generator and inverter in operation
Not bad for for a century old turbine. The picture below is the grid side inverter data panel showing us exporting 103.6kW to the grid. The predicted maximum output based on factory Leffel data would have been 111 kW. This is before inverter and mechanical conversion losses -AND- with a new turbine. We calculated a 2.6% inverter loss from AC to DC to AC. Dedicated two quadrant solar inverters typically lose 3% and we added a second conversion! At one point we exported 105.6kW but I did not get a picture... Yes, that is 733 DC volts on the DC bus!
The SEL 735 provides secondary IEEE 1547 protection and this Dominion Power supplied SEL controls the main contactor in the inverter cabinet. The SEL is a utility grade power meter and recorder so it also measures harmonics, power factor, voltage, amperage, and lots of other data. We installed one on our main cabinet as well so now we can measure power output directly from the line side inverter. Note the perfect power factor (1.00); not only does the inverter deliver perfect power factor but it automatically augments and corrects sagging grid power factor and voltage locally. Our neighbors enjoy very "clean" power.
The picture below is our Fluke power meter data when we were tuning the inverter. Note the voltage imbalance between A, B and C phases supplied by Dominion Power. At times the imbalance on the grid was much worse (nearing 5%) but, no worries. The inverter balanced the legs automatically and the generator windings never saw this imbalance so they were never stressed. I love the Fluke meter but it requires working inside an energized cabinet so our cabinet installed SEL 735 will help mitigate that concern. We have primary IEEE 1547 protection provided by the inverter and secondary protection (X 2) provided but each SEL735.