What is Solar SCADA?

SCADA (supervisory control and data acquisition) is a large scale control system for automated industrial processes. The term SCADA usually refers to centralized systems which monitor and control entire sites, or complexes of systems spread out over large areas ( anything from an industrial plant to a nation). Most control and monitoring actions are performed automatically by PLC, PC Based, or PAC systems. A SCADA system includes the following features:

Data Acquisition - SCADA need to collect data from field equipments such as PV Inverters, meter readings, environment sensors like irradiation and temperature, string meters. These equipments are communicated to PLCs or PC for data and status reports via communication interface like RS485 or TCP. Data is then compiled and formatted in such a way that a workstation operator using the HMI can make supervisory decisions to adjust or override normal controls. Data may also be fed to database and backup server, often built on a commodity database management system or remote cloud server to allow trending and other analytical auditing.

Human-Machine Interface - As data collect by SCADA system, it need to display the information like light intensity, energy, and the power generated on the farm per transformer unit and delivery unit across the entire site by graphical objects. It must be graphic intuitively that operators or users can check the status quickly and easily.

Remote Monitoring 
– In order to prevent yielding loss, system administrators need to be able to remotely check the yielding information, inverter status, panel status, and environment condition. SCADA system need to include web function on it or support mobile devices. Once any events happened, they can check it remotely to solve the issue and handle the event in time.

Event and Alarm Management – SCADA system need to alert users and system administrators to alarms and system malfunctions. The function for sending and receiving email messages, used in conjunction with schedules, warns mobile operators according to their availability.

Archiving – The SCADA system stores the data acquired from the site concerning production, maintenance, status, and reports, etc. It needs to save in local workstation and also backup to remote server for archiving.

Database – All the SCADA information need to export to an SQL Server database for centralizing and analyzing the production of the various farms. Users or system administrators can apply the database to query the history data in order to statistic or analyze the performance of the solar plant. The database can be setup in remotely cloud server or locally database server.

Flexibility for Future Expansion – SCADA system must keep the flexibility for future added solar panels, inverters, environment sensors, string meters, or other equipments.

What are the Differences between Utility and Commercial Solar SCADA?

Usually, a utility scale solar plant is more than 5MW. A commercial solar plant is from 10kW to 5MW. A commercial scale solar plant also needs the SCADA function to make sure their solar plant keep working in good condition. The commercial plant needs all SCADA function, but needs to be much lower cost than utility one. In addition, commercial solar plant usually setup in government organization, schools, and enterprises. Generating power is not the only purpose, but they also need to show the information to people for demonstration and education.
A PAC system combines with PLCs and PC function in one platform. It keeps both the PLC’s stability and PC’s calculation abilities at the same time. It provides the necessary functions of a SCADA system, but also needs to help system installers can setup in shortest time and help customer fulfill their demonstration function. It needs to be a standardize and modularize platform with the integration flexibility and future expansion ability. A commercial SCADA system needs to have following features:
• Need to have all function as utility scale SCADA.
• Need to be a more cost effective way than utility scale SCADA.
• Need to be a standardize and stable solution.
• Need to have more flexibility and future expansion.
• Need to have more powerful function on demonstration.

Market Trend

Utility-Scale & Commercial-Scale Lead PV Market Growth

According to EIA's new survey-based estimate of total solar capacity, total on-grid photovoltaic (PV) capacity nearly doubled in 2011, led by particularly strong growth in both utility-scale PV and commercial sector PV capacity. Although 2011 was a record year for solar PV growth, solar PV capacity has consistently grown over the past few years. The Interstate Renewable Energy Council (IREC) reports that total grid-connected PV capacity quadrupled between 2008 and 2011.

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