Hopsol Africa specialises in the design and construction of solar power plants, targeting commercial, industrial and private customers, as well as direct feed-in independent power supply plants. The recent challenge the company faced was to meet the strict power and voltage control requirements of Nampower, the Namibian national power utility, in terms of reaction speed and variable ramp rates for a distributed inverter architecture. Also, an effective remote monitoring solution was sought to enable fast and accurate detection and detailed fault finding in case of a loss in power production.
The Hopsol problem
Existing control and monitoring solutions for solar power plants are usually supplied and imported from overseas and do not cater for some specific local requirements. Due to a previous relationship with Hopsol, entailing the supply of various monitoring solutions, PCS Global Namibia, a leading industrial control and automation engineering company, was tasked with finding a solution that would address these issues.
Hopsol needed to meet the control requirements for a direct feed-in supply to Nampower. The monitoring solution also had to be an enabling tool for the maintenance department, which requires effective and intelligent information on all aspects of the solar power plant.
The PCS solution
The solution proposed by PCS Global Namibia was a central control interface that meets all requirements in terms of reaction time and variable ramp rates, for the approximately 100 inverters that make up the plant. The monitoring solution would offer a combination of dedicated SMS alarms, informational scada interface, and intelligent diagnostic algorithms which are able to measure the plant efficiency in real-time, based on the available solar radiation.
To achieve the required speed for the closed loop control was a challenge due to the distributed architecture. The diagnostic algorithms required a new level of data processing and manipulation which is evidence of the new possibilities introduced by big data technologies in industrial control.
The benefits
Hopsol recognised the benefits that the proposed solution offered over the lifetime of the plant. The solution was developed entirely by PCS’ in-house programming capabilities. Together with the Siemens S7-1500 PLC platform and a state of the art scada framework, a robust architecture was implemented.
The system permits the control of active power, power factor and voltage, by either Hopsol or Nampower. The monitoring solution allows the real-time calculation of any inverter deviations and real-time performance ratio of the plant. The advanced remote notification system allows the maintenance team to respond at a moment’s notice while being armed with all necessary information. Since monitoring in remote areas is challenging, PCS Global Namibia developed an additional means of notification to send bidirectional data even when most communication to the plant has broken down due to outside or unforeseen events.
The Hopsol solar plant meets all the stringent demands for controlling a direct feed-in power plant, which becomes more important as the national grid is expanded by an array of renewable energy sources. The solution is also being used for the construction of several new solar power plants currently being built by Hopsol. Furthermore, PCS Global continues to offer support and implement optimisations for this solution.
As renewable energies acquire an ever growing share of the total power supply in a country, effective control capabilities and an advanced monitoring and notification platform becomes an important component of a successful solar power plant implementation.
For more information contact Siegfried Herholdt, PCS Global Namibia, +264 85 646 5094, siggi@pcsglobal.com.na, www.pcsglobal.com.na
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