SECTION 4
OPERATION
Current Imbalance Detection
In the event of phase-to-phase current imbalance of greater than 20% between phases, the inverter will ex- ecute an orderly shutdown, and annunciate a fault at the operator interface. See Section 5, Troubleshooting, for further information on this fault condition.
DC Overvoltage Detection
In the event of DC voltage greater than 600Vdc, the PV-225208 will execute an orderly shutdown and annunciate a fault to the operator interface. If DC voltage remains greater than 600Vdc, the PV-225208 may be irreparably damaged. See Section 5, troubleshooting for further information on this fault condition.
Peak Power Tracking
The PV-225208 control software employs an active PV peak power tracker designed to maintain maximum power output from the PV array at all times of operation. The peak power voltage point varies primarily depending upon the temperature of the PV cells. The PV-225208 constantly seeks the optimum voltage and current operating points of the PV array to maintain maximum PV power output. Upon PV wake-up, the power tracker will increase power while ramping PV array voltage to the PV maximum power voltage refer- ence setpoint (PPT V Ref). The change rate is governed by the power point ramp time setpoint (PPT Ramp T). Once the PV voltage is ramped to the reference setpoint, the PCU begins to adjust the commanded PV voltage around the reference setpoint, seeking maximum PV power. The power tracker may only adjust the operating voltage +/- 20% of PPT V Ref. The PV maximum power voltage step and update rate are user setable (PPT V Step and PPT Rate, respectively).
If available PV power is above the maximum allowable power level of the PV-225208, the power tracker will increase voltage as needed to maintain output power below rated maximum.
The minimum operating voltage of the PV-225208 is 330 VDC. The power tracker will not track voltage below this point, regardless of the reference voltage setpoint.
Automatic Sleep Test
Toward the end of every solar day, the PV-225208 automatically determines when to stop producing power dependent upon the output power of the inverter. As the net output power of the PV-225208 nears zero, a timer is started to allow the inverter to ride through any brief irradiance reductions.
OPERATOR INTERFACE
The operator interface display consists of two main menu levels: The read parameter menu and the write parameter menu. The read parameter menu consists of all system parameters, the date and time. These can be viewed any time the PV-225208 has control power.
The write parameter menu consists of a goal state sub-menu, and all system write parameters. The write parameter menu is password protected and may only be changed by trained service technicians. In particular are parameters relating to utility protection setpoints. These have been set in the factory to
DOCUMENT: 151811 | PV-225208 Photovoltaic Inverter | 4-3 |
| Operation and Maintenance Manual | |
