Photovoltaic Data Gathering and Processingat CTU Prague

Martin Molhanec, M.Sc., Ph.D.

Department of Electrical TechnologyFaculty of Electrical Engineering

Czech Technical UniversityPrague, Czech Republic

Introduction

The departmental PV system FVS 2003A was installed at 2002 year on the roof of our faculty.

The system is build up from 3 independent subsystems (@1kW).

Each subsystem consists of 10 PV panels.

The PV system is connected to the standard 230V, 50 Hz power supply network.

All produced energy is consumed at faculty building.

Introduction

Following data are collected from every PV subsystem

PV field output voltage, current and poweroutput voltage, current and power of the converters total power delivered to the network temperature of convertors

Addition informationmomentary output power of PV fieldPV field temperature incident radiation intensity

PV panels

RS 422

RS 422

t °

DATA LOGGER

ADDITIONAL DATA

DISPLAY PANELS

USER

RS 232

CONVERTOR

DATA LOGGER

RS 232

ADDER DEVICE

RS 232

This solution has many disadvantages

PVDA can be processed only manual way by special programme from PV system supplier and this process can not be automated.

The collected data can be only manually processed for subsequent utilization.

The web presentation of PV data is created manually. This solution necessitates a good knowledge of HTML and web pages development. A direct access to the web server directories is also required.

A temporary solution

created at 2005 year as a result of diploma thesis.A better integration with the faculty network cabling system.An easier possibility of moving data output of the PV system from one office to another office on the same corridor.Standardized output of cabling by commonly used twist pair network jacks.Direct connectivity to the web server room.The second cabling system was prepared for future IP based method of data acquisition.

A temporary solution

The web presentation was created by the following scenario

Getting data from data logger by standard supplier’s tool.Sending preserved data from a client workstation by a special tool up to the web server directory.Automated on server processing of received data into the database located on the web server.And finally, a presentation of stored PV data on web server pages.

A temporary solution

The main disadvantages Poor software implementation and tools instability.

Not fully automated process.

Problematic expansibility and modification.

Present time solution

Towards the end of the 2005 year was installed a new data logger with standard (RS485/RS422) and a new IP (Internet) based connectivity.

The works on the new automated graphical presentation and processing of PV data in the context of our new Internet based connectivity are in progress.

PV panels

RS 422

RS 485

t °

DATA LOGGER

ADDITIONAL DATA

DISPLAY PANELS

USER

RS 232

CONVERTOR

RS 232

WEB SERVER

INTERNETIP CONNECTION

FVS 2300ECTU Prague

WEB SERVERCZREA

WEB SERVERCTU Prague

GET HTTP

GET HTTP

Disadvantages of contemporary solution

Dependency on CZREA web server.

Impossibility to easily change the address of the target (receiver) web server.

Impossibility to obtain historical data from the data logger.

FUTURE AND IDEAS

Firstly we want to complete our Internet based PV data acquisition project and create a comfortable presentation of collected PV data on our departmental web server pages.

A farther objective is an integration of processing of our PV data with meteorological data collected by the Department of Telecommunications Engineering.

Our strategic goal is to create a complex information system about the photovoltaic education, e-learning and research.

Czech Technical University in PragueFaculty of Electrical Engineering

Department of Electrical Technology

email: molhanec@fel.cvut.czhttp://k313.feld.cvut.cz

http://martin.feld.cvut.cz/~molhanecThank you for your

attention!