A power generation system including a plurality of photovoltaic power generation systems and a supervisory remote control apparatus which supervises and controls a state of the photovoltaic power generation systems (101... 10N), wherein each of the photovoltaic power generation systems comprises a photovoltaic array (41...4N); a power conditioner (21...2N) which converts direct-current power generated by the photovoltaic array into desired direct-current power, further converts it into alternating-current power, and supplies it to the alternating-current power system, or converts direct-current power generated by the photovoltaic array into alternating-current power and supplies it to the alternating-current power system; and a measurement apparatus (31...3N) which measures power generating conditions of the photovoltaic array; a control switching apparatus (213... 2N3) that switches MPPT control, by which the power conditioner (21...2N) receives a direct-current voltage command or a direct current command and a control switching command from the supervisory remote control apparatus through a communication system and an output from the power conversion apparatus (211...21N) included in the power conditioner (21...2N) becomes maximum, to voltage control or current control using the direct-current voltage command (Vref) or the direct current command (Iref); a power generating condition detector (311... 3N1, 312...3N2) as solar radiation intensity detector including actinometers (311... 3N1) that measure solar radiation intensity as power generating conditions of the respective photovoltaic arrays (41... 4N); a direct-current voltage detector (214... 2N4) which detects a direct-current voltage that is an output from the photovoltaic array; a direct current detector (215...2N5) which detects a direct current that is an output from the photovoltaic array, the power generation system further comprising: the communication system which has communication apparatuses (12, 212... 2N2, 313... 3N3) installed in the supervisory remote control apparatus, the power conditioner (21... 2N), and the measurement apparatus (31... 3N), respectively, and comprises a signal transmission path (911...9N1, 912...9N2, 913...9N3) which enables communication between the communication apparatus in the supervisory remote control apparatus and the communication apparatus (313...3N3) in the measurement apparatus (31...3N) and between the communication apparatus in the supervisory remote control apparatus and the communication apparatus (212...2N2) in the power conditioner (21...2N), wherein the supervisory remote control apparatus comprises a curve trace apparatus which is installed in the supervisory remote control apparatus, fetches a direct current detection value detected by the direct current detector (215... 2N5) and a direct-current voltage detection value detected by the direct-current voltage detector (214... 2N4), traces an I-V characteristic diagram of the photovoltaic array, and also traces power generating conditions detected by the power generating condition detector (311... 3N1, 312... 3N2) on the I-V characteristic diagram, and characterized in that the I-V characteristic diagram and the power generating condition detection value being traced in synchronization with transmission of the direct-current voltage command or the direct current command and the control switching command from the supervisory remote control apparatus to the control switching apparatus (213...2N3), and the I-V characteristic diagram and the power generating condition detection value being displayed. the communication system which has communication apparatuses (12, 212... 2N2, 313... 3N3) installed in the supervisory remote control apparatus, the power conditioner (21... 2N), and the measurement apparatus (31... 3N), respectively, and comprises a signal transmission path (911...9N1, 912...9N2, 913...9N3) which enables communication between the communication apparatus in the supervisory remote control apparatus and the communication apparatus (313...3N3) in the measurement apparatus (31...3N) and between the communication apparatus in the supervisory remote control apparatus and the communication apparatus (212...2N2) in the power conditioner (21...2N), wherein the supervisory remote control apparatus comprises a curve trace apparatus which is installed in the supervisory remote control apparatus, fetches a direct current detection value detected by the direct current detector (215... 2N5) and a direct-current voltage detection value detected by the direct-current voltage detector (214... 2N4), traces an I-V characteristic diagram of the photovoltaic array, and also traces power generating conditions detected by the power generating condition detector (311... 3N1, 312... 3N2) on the I-V characteristic diagram, and characterized in that the I-V characteristic diagram and the power generating condition detection value being traced in synchronization with transmission of the direct-current voltage command or the direct current command and the control switching command from the supervisory remote control apparatus to the control switching apparatus (213...2N3), and the I-V characteristic diagram and the power generating condition detection value being displayed.