DESCRIPTION

Technical Description

Feeding electricity from photovoltaic solar modules into the mains grid requires several special system components. These components enable conversion and capture of the solar electricity and ensure  system safety.

The ET 250.01 unit contains these components and is conceptualized as an extension for the ET 250 trainer.

The photovoltaic DC current from ET 250 is fed to the input of ET 250.01 via a connection cable. Inside ET 250.01 the DC current passes safety devices and enters the inverter. The inverter transforms the DC  into  AC current. The inverter also  optimizes voltage and current to ensure that the photovoltaivc modules produce maximum possible power.

The inverter output provides an AC voltage with appropriate level and frequency to enable feeding into the mains grid. The amount of fed in electricity is captured by a modern two way electricity meter and the own consumtion is captured by an energy logger.   

Comparing electrical power of the DC input and the AC output enables determination of the inverter efficiency. The dependence of the inverter efficiency on the total electrical power  can be measured in further experiments.

The well-structured instructional material sets out the basic principles and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments

- familiarisation with components from grid connected use of photovoltaic power
- functioning of a DC switch-disconnector and over voltage protection
- functioning of a grid connected inverter with maximum power point tracking
- dependence of the inverter efficiency on the workload
- function of modern energy meters