(JP11251615-A)   NOVELTY - The photovoltaic power generating system includes several strings connected in parallel. The strings comprise several solar cell modules connected in series. The solar cell array may generate heat with the aid of an external power source. A current switch is individually switchable for each string. A control unit individually controls the current switches. A current is applied to each string in sequence so that heat is generated.    USE - For generating power using photovoltaic cells, and also for generating heat as e.g. a snow melting device.    ADVANTAGE - Prevents the solar cell array from being heated non-uniformly. Operates correctly even if one solar cell string is defective. Reduces the size of the inverter needed to drive the heater.    (CN1236213-A)   NOVELTY - The photovoltaic power generating system includes several strings connected in parallel. The strings comprise several solar cell modules connected in series. The solar cell array may generate heat with the aid of an external power source. A current switch is individually switchable for each string. A control unit individually controls the current switches. A current is applied to each string in sequence so that heat is generated.    USE - For generating power using photovoltaic cells, and also for generating heat as e.g. a snow melting device.    ADVANTAGE - Prevents the solar cell array from being heated non-uniformly. Operates correctly even if one solar cell string is defective. Reduces the size of the inverter needed to drive the heater.    (US6093885-A)   NOVELTY - The photovoltaic power generating system includes several strings connected in parallel. The strings comprise several solar cell modules connected in series. The solar cell array may generate heat with the aid of an external power source. A current switch is individually switchable for each string. A control unit individually controls the current switches. A current is applied to each string in sequence so that heat is generated.    USE - For generating power using photovoltaic cells, and also for generating heat as e.g. a snow melting device.    ADVANTAGE - Prevents the solar cell array from being heated non-uniformly. Operates correctly even if one solar cell string is defective. Reduces the size of the inverter needed to drive the heater.