Grid integration of distributed renewable energy sources: a network planning perspective

With the drive for cleaner energy, Independent power producers (IPP’s) have to find suitable potential land sites that meet their renewable project needs and that prove to be technically feasible to integrate into the nearest distribution electrical infrastructure. Project feasibility for utility grid connection can in certain instances be directed to a specific area due to resource availability and existing electrical plant capability. This invariability leads to multiple establishments of renewable energy plants in the same geographic location. Distribution substations and high voltage (HV) lines in the South African National utility, Eskom, are planned and constructed based on simulation models derived from power system models built in DIgSILENT Powerfactory analysis software. For a Network Planning Engineer, planning for this integration can be become quite complex in a multi-machine scenario as above. This dissertation provides network planning criteria that a planning engineer in the utility can successfully use to plan for this integration. Three sets of criteria are established. With the inclusion of widespread distributed generation in close proximity of each other, sharing the same grid electrical infrastructure, a critical path of HV electrical elements exists, which the effects of the combined generation control. The first set of planning criteria is derived from the analysis of locating this critical path. This is determined by means of using iterative programming and calculations. Grid voltage stability is one the most important factors in determining the feasibility of generator grid integration. The voltage stability effects of the Eskom Distribution network to which these generating plants connect to, are analysed and tabulated results established. This will enable the utility to determine the location of a specific size of renewable plant, just by knowing the grid strength and not going into detail voltage stability studies. For the second set of planning criteria three sets of network range strengths are identified with corresponding ratios of grid strengths to generator short circuit current contributions. Successfully integrating DG to the grid also has many technical and cost solutions of network configurations. The third set of planning criteria identifies four generic network configurations and the building blocks of physically costing the engineering integration. Solar density maps provide an indication of proposed MW output in a particular area. In this research, solar density maps are used to identify the maximum connecting generation to the electrical grid in feasible geographic areas. The results derived from this study enable the planning engineer and/or developer to better plan the optimal location of a PV project wrt the chosen geographic area of KZN. This study case may be extended to other technologies leading to a more concise framework of network planning for renewable project integration.

Grantor dc:publisher.institution

Department of Electrical Engineering

Year dc:date.issued

2014

Author dc:creator

• Ramdhin, Avinash

Advisor dc:contributor.advisor

• Chowdhury, S

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/13201

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/13201