SECTION 4
OPERATION
DESCRIPTION OF SYSTEM OPERATION
Overview
The PV-225208 is a fully automated grid-tied photovoltaic inverter. Manual interaction or control of the inverter is necessary only in the event of a system fault. The following conditions govern PV-225208 operation:
•Stable utility voltage and frequency must be present for all states of operation.
•Fault states are automatic from any state of operation. A fault will cause the PV-225208 to immediately stop processing all power. The fault condition will be reported to the operator interface.
•The on/off switch, located on the front door of the PV-225208, must be switched to the on position for all operating states.
•Cycling the on/off switch attempts to clear any system faults and return the PV-225208 to normal opera- tion.
Operating States
A state machine implemented within the PCU control software governs the operation of the PV225208. There are five steady-state operating states and numerous intermediate transition states. The intermediate transition states provide an orderly progression from one operating state to the next. The user has the ability to manually transition the PV-225208 between operating states from the operator interface keypad. Manual transitions are initiated by entering a ‘Goal State’, where the goal state is the desired operating state. Given all applicable system parameters are within acceptable limits, and the request is valid within the state machine, the PV- 225208 will initiate the proper sequence of operations necessary to progress to the requested goal state. Refer to Figure 4-3 for a description of valid state transitions.
•Shutdown: The line interface controller is idle. The PCU monitors the status of the PV array and utility grid, waiting in standby until the PV array is available to produce power to the grid.
•Fault: The PV-225208 has encountered a fault condition. When this happens, regardless of the PV- 225208 state-of-operation, the PV-225208 will stop processing all power and execute an orderly system shutdown. Adescription of the fault and fault code will appear on the operator interface LCD. The Fault state may be cleared from the keypad once the cause of the fault has been corrected. See Section 5 for a complete description of all fault codes.
•Manual Current: This operating state is provided to evaluate the existing PV array V-I character- istics. The PV controller regulates a constant amount of PV current as commanded by the user from the operator interface keypad, up to the PV current limit of the PV-225208. If the user commands more PV current than is available, the DC bus voltage will drop below the minimum bus voltage level and the PV-225208 will return to Sleeping mode.
•Matrix Test: This operating state is provided to verify proper operation of the matrix and associ- ated control electronics. There is no power transfer between the PV and utility in this mode.
•Power Tracking: This is the standard operating state of the PV-225208. The PV-225208 maximum power tracker will demand maximum power from the PV array, given sufficient PV irradiance.
DOCUMENT: 151811 | PV-225208 Photovoltaic Inverter | 4-1 |
| Operation and Maintenance Manual | |
