A photovoltaic device includes a first group of photovoltaic cells of a first cell type, the first group of photovoltaic cells operable to produce a first current and a first voltage, and a second group of photovoltaic cells of a second cell type that is different than the first cell type, the second group of photovoltaic cells operable to produce a second current and a second voltage. A first power electronics unit is connected to the first group of photovoltaic cells, and a second power electronics unit is connected to the second group of photovoltaic cells. The second power electronics unit is separate from and not communicating with the first power electronics unit. A control device is operable to vary a first property of the first power electronics unit to vary the first current and the first voltage and to vary a second property of the second power electronics unit to vary the second voltage and the second current independent of the first voltage and the first current.

A load testing device includes a connection unit to which a power source being tested is connected, a hydrogen generating unit that performs electrolysis based on power supplied from the power source being tested to generate hydrogen, two or more supply units to which hydrogen obtained in the hydrogen generating unit passes and to which a portable tank is removably attached, and an operational unit that has a load amount adjustment switch and a display unit. The load amount of the hydrogen generating unit is switched depending on an operational state of the load amount adjustment switch. The display unit displays at least one of an attachment status of the portable tank and a filling status of hydrogen in the two or more supply units.

The disclosure is directed to a detection device for detecting a fault current (I.sub.fault) at a PV generator and/or at DC lines of a PV installation assigned to the PV generator. The PV generator has at least one first PV string and a second PV string, which are connected to a PV inverter of the PV installation via in each case two DC lines. In this case, the detection device has at least one current transformer and an evaluation circuit connected to the at least one current transformer. The current transformer can be used jointly by the first PV string and the second PV string, wherein a measurement signal of the jointly usable current transformer represents a difference between a first summation current (I.sub.sum,1) flowing from the first PV string towards the ground potential (PE) and a second summation current (I.sub.sum,2) flowing from the second PV string towards the ground potential (PE). The fault current (I.sub.fault), when it arises, is a part of the first summation current (I.sub.sum,1) and/or the second summation current (I.sub.sum,2). The disclosure also includes a PV inverter having a corresponding detection device and also a method for detecting a fault current (I.sub.fault).

The disclosure is directed to a detection device for detecting a fault current (I.sub.fault) at a PV generator and/or at DC lines of a PV installation assigned to the PV generator. The PV generator has at least one first PV string and a second PV string, which are connected to a PV inverter of the PV installation via in each case two DC lines. In this case, the detection device has at least one current transformer and an evaluation circuit connected to the at least one current transformer. The current transformer can be used jointly by the first PV string and the second PV string, wherein a measurement signal of the jointly usable current transformer represents a difference between a first summation current (I.sub.sum,1) flowing from the first PV string towards the ground potential (PE) and a second summation current (I.sub.sum,2) flowing from the second PV string towards the ground potential (PE). The fault current (I.sub.fault), when it arises, is a part of the first summation current (I.sub.sum,1) and/or the second summation current (I.sub.sum,2). The disclosure also includes a PV inverter having a corresponding detection device and also a method for detecting a fault current (I.sub.fault).

The subject of this invention is a method for testing the data and control interface of individual machines intended for interconnection in an inline system for solar cell production. Furthermore, an Interface-Tester suitable for executing the testing method is disclosed. The method for testing comprises the steps of feeding a dummy workpiece to the tested machine and connecting the interface tester to the standard interface of the machine. Consecutively the interface tester sends controlling signals to the machine and receives the signals from the tested machine. The received signals are compared to reference signals and evaluated. The interface tester comprises a standard interface for coupling the machines in an inline system for solar cell production. Furthermore, the interface tester is equipped with at least one CPU, a volatile and/or non-volatile memory, communication modules, couplers and connectors and at least one human-machine interface.

A system for estimating a real-time renewable energy generation quantity according to an embodiment of the present disclosure includes a site setting unit for setting a benchmarking group based on geographical locations of a plurality of renewable energy generation sites and setting a benchmarking site for each benchmarking group, a site generation quantity calculation unit for calculating a real-time generation quantity prediction value of each of sites except the benchmarking site among the sites included in the benchmarking group by using a preset prediction model based on a real-time generation quantity actual-measurement value of the corresponding benchmarking site, and a total generation quantity estimation unit for estimating a total real-time generation quantity of all the sites by summing the calculated real-time generation quantity prediction values for the respective sites and the real-time generation quantity actual-measurement value of the benchmarking site.

A system for estimating a real-time renewable energy generation quantity according to an embodiment of the present disclosure includes a site setting unit for setting a benchmarking group based on geographical locations of a plurality of renewable energy generation sites and setting a benchmarking site for each benchmarking group, a site generation quantity calculation unit for calculating a real-time generation quantity prediction value of each of sites except the benchmarking site among the sites included in the benchmarking group by using a preset prediction model based on a real-time generation quantity actual-measurement value of the corresponding benchmarking site, and a total generation quantity estimation unit for estimating a total real-time generation quantity of all the sites by summing the calculated real-time generation quantity prediction values for the respective sites and the real-time generation quantity actual-measurement value of the benchmarking site.

The present invention relates to a fault detection system and method of a photovoltaic module and string. The fault detection system of a photovoltaic module and string includes a measurement input unit receiving a current power generation performance measurement value of the photovoltaic module and string from the outside, an estimation calculating unit calculating a power generation performance estimation value of the photovoltaic module and string based on input current environmental conditions, and a fault determining unit determining whether the photovoltaic module and string have a fault by comparing and analyzing the power generation performance measurement value from the measurement input unit and the power generation performance estimation value from the estimation calculating unit, wherein the photovoltaic module is configured as a double-sided or single-sided photovoltaic module.

The present invention relates to a fault detection system and method of a photovoltaic module and string. The fault detection system of a photovoltaic module and string includes a measurement input unit receiving a current power generation performance measurement value of the photovoltaic module and string from the outside, an estimation calculating unit calculating a power generation performance estimation value of the photovoltaic module and string based on input current environmental conditions, and a fault determining unit determining whether the photovoltaic module and string have a fault by comparing and analyzing the power generation performance measurement value from the measurement input unit and the power generation performance estimation value from the estimation calculating unit, wherein the photovoltaic module is configured as a double-sided or single-sided photovoltaic module.

A solar panel cleaning system includes: an automated cleaning device for cleaning a surface of a reference cell panel; a cleaning device controller in communication with a motor of the automated cleaning device, the cleaning device controller configured to receive a signal corresponding to measurement of a current of photovoltaic system. The cleaning device controller activates the automated cleaning device to clean a surface of the reference cell panel when the received signal indicates that a measurement of the current of the photovoltaic system is to be taken.