Safety mechanisms, wake up and shutdown methods in distributed power installations
A distributed power system including multiple DC power sources and multiple power modules. The power modules include inputs coupled respectively to the DC power sources and outputs coupled in series to form a serial string. An inverter is coupled to the serial string. The inverter converts power input from the serial string to output power. A signaling mechanism between the inverter and the power module is adapted for controlling operation of the power modules.
1. A method for operating a photovoltaic system for feeding into a power supply system, the photovoltaic system comprising at least one input for connection to a solar panel and at least one output for connection to an inverter, comprising:
determining a level of a low-frequency signal at the at least one output, wherein the signal comprises a frequency which corresponds to system frequency in the power supply system, and wherein the signal is provided inherently by an inverter without being generated by a dedicated signal generator;
connecting the at least one output to the at least one input, if the level of the low-frequency signal is detected; and
de-energizing the at least one output if the low-frequency signal is not detected.
2. The method as claimed in claim 1 , wherein the low-frequency signal comprises a frequency which corresponds to an integral multiple of the system frequency in the power supply system.
3. The method as claimed in claim 1 , wherein the low-frequency signal is a voltage signal.
4. The method as claimed in claim 1 , wherein the low-frequency signal is a current signal.