Parameter Definition
The parameters measured and presented in this website are all in accordance with IEC:61724 standard which has been prepared by International Electrotechnical Commission (IEC) technical committee 82: Solar photovoltaic energy systems. The University of Tehran PV datacenter is established in order to provide a comprehensive monitoring and analysis of the electrical performance of Photovoltaic (PV) systems. The intent of this evaluation is to provide a performance monitoring of different PV plants in Tehran environmental condition. Following is the description of all variables to be shown in this website.

A. Meteorological Data:

Since the performance of PV plant strongly depends on the environmental and meteorological condition, it is important to measure and report this data.

A.1: Global Irradiance on the panel surface (GI):

Irradiance data are recorded in the plane of the array for use in the performance analysis of the PV system. Since the annual optimal tilt angle in Tehran is about 30°, the irradiance is measured at this angle by means of SMA Sensorbox in five minutes interval.

A.2: Ambient Temperature (Tam):

Ambient temperature is measured at near PV plants, by means of SMA Temperature sensor located in solar radiation shield.

A.3: Module Temperature (Tm):

Module temperature is measured by means of SMA temperature sensor located on the back of PV module.

A.4: Wind Speed (SW)

Wind speed is measured at height of PV module by means of SMA Anemometer.

B. Electrical Data:

B.1: Photovoltaic Array Output Voltage and Current (Vpv & Ipv)

Voltage and current of PV array of each PV Plant are measured by means of built-in data acquisition system of the inverter.

B.2: Inverter Output Voltage and Current (VAC & IAC )

Voltage and current of Inverter of each PV Plant are measured by means of built-in data acquisition system of the inverter.

B.3: Inverter Output Power and Photovoltaic Output Power (PAC & PPV )

Inverter Output Power and Photovoltaic Output Power of each PV Plant are measured by means of built-in data acquisition system of the inverter.

B.4: Inverter Perunit Output Power and Photovoltaic Perunit Output Power (PFP.U & PPVP.U )

In order to provide a comparable data by which all power plant can be assessed in a unique form, the power of PV plant is down scaled and divided by the peak value of PV arrays. Both PV power and inverter power can be performed in this way. In addition to daily profile of this parameter, the monthly and yearly profile of the specific yield of both array and inverter energy are measured.

B.5: Inverter Efficiency (ηInverter):

In order to have a performance evaluation of inverter its efficiency is measured considering output and input power of inverter.

B.6: Inverter Frequency (F):

Frequency of output power of inverter is measured and reported by the inverter.