The Credem Group controls and manages the photovoltaic system using an Electrex monitoring system
The Credem Banking Group, has always paid attention to the issues of cost management and the return on investment for each of their assets.The Credem Banking Group, has always paid attention to the issues of cost management and the return on investment for each of their assests. When they decided to install a photovoltaic system at one of their properties, it was considered appropriate to adopt a system for measuring and managing the plant, in order to ensure a more efficient and effective management. The choice has fallen on an Electrex monitoring system which provides to the Energy Manager and the maintainer a continuous control on the operation of each component (inverter, panels, etc..) In order to avoid total or partial production blocking and at the same time allows to measure the energy used.
Composition of the system
The monitoring system includes the following devices:
- n. 5 X3M D6 H 85÷265V ENERGY DATA MANAGER
- n. 102 FEMTO D4 DC RS485 230-240V 1DI 2DO ENERGY ANALYZER
- n. 14 YOCTO NET D4 NETWORK BRIDGE DATA LOGGER
- n. 3 YOCTO I-O D4 8÷32V INPUT-OUTPUT DEVICE
- Software Energy Brain
- Nr. 1 Irradiance sensor
- Nr. 1 Temperature sensor
Automatic periodic reports
The system automatically generates and sends, to authorized users, reports weekly, monthly and yearly, in graphical and numerical formats, which contain various information including: values of power and energy produced collected every 15 minutes of each inverter, value of the energy of each of the 102 strings produced during the day; measurement of irradiance, module’s temperature, etc..
Also the generation of the production log registry for the Energy Authority, which normally is compiled manually, has been automated using the report option.
Alarms/Alerts Management
Various alarms have been set in order to reveal eventual anomalies of the plant on time and with different priorities.
The most serious event is the failure of one or more inverters. To detect this abnormality it is used the threshold value of irradiance and the value of power or current. This allows you to highlight a malfunction due to the inverters, switch on the breaker or a problem in the field. In practice, if the measured radiation exceeds the threshold set, all the inverters must be in production and thus have a value of power or power different from 0.
An email reporting the problem will be sent in case this anomaly will occur. It is possible to define a delay time in order to limit any false alarms due to the fact that the radiation sensor is only one while the inverters are connected to modules that can be found in different areas of the plant and therefore not irradiated in the same way. The alarm stops when the inverter returns in operation.
Event of minor importance is the failure of a string. To detect this anomaly it is used the measured current value on the string compared with the measured value of one of the strings by side.And it is possible to configure the system so that if the difference of the value of current between 2 strings is greater than a certain percentage, an alarm message is sent.
The productivity of the plant is monitored and reported with the same mode of control of the string. The system verifies that the delivered power measured by the instrument is greater than (in kW) of a given value multiplied by the value of radiation (w/m2). If not an email alert is generated.
WEB pages
Several web pages were built and uploaded on various Yocto net that can be accessed via PC, tablet and smart phones. The pages display among other things: an aerial view of all the panels; various summary pages with the values reported by Electrex devices and alarm status related; the values of the instantaneous power, the energy produced by photovoltaic, the energy used for productive activities, etc..; indication of the theoretical values and those actually detected, an indication of the savings of TOE (Ton Oil Equivalent) and the value of TCO2 (Tonnes of carbon dioxide) not released into the atmosphere from the starting day.