However, since power sources 101a-101d are connected in series to single MPPT 107, MPPT 107 selects a maximum power point which is some average of the maximum power points of the individual serially connected sources 101. In practice, it is very likely that MPPT 107 would operate at an I-V point that is optimum for only a few or none of sources 101. In the example of FIG. 1B, the selected point is the maximum power point for source 101b, but is off the maximum power point for sources 101a, 101c and 101d. Consequently, the arrangement is not operated at best achievable efficiency.

The present applicant has disclosed in co-pending U.S. application Ser. No. 11/950,271 entitled “Distributed Power Harvesting System Using DC Power Sources”, the use of an electrical power converter, e.g., DC-to-DC converter, attached to the output of each power source, e.g., photovoltaic panel. The electrical power converter converts input power to output power by monitoring and controlling the input power at a maximum power level. This system may be used also to address the anti-islanding issue.

The term “signaling” or “signaling mechanism” as used herein refers to either a signal modulated on an electromagnetic carrier signal or a simple unmodulated signal such as an on/off signal “keep alive” signal or “dry contact” signal. For a modulated signal, the modulation method may be by any such method known in the art by way of example, frequency modulation (FM) transmission, amplitude modulation (AM), FSK (frequency shift keying) modulation, PSK (phase shift keying) modulation, various QAM (Quadrature amplitude modulation) constellations, or any other method of modulation.