Smart Energy Technologies

Technical Symposium

Optimal Future Sub-Transmission Volt-Var Planning Tool to Enable High Distributed PV Penetration

Tuesday, September 25
11:20 AM - 11:40 AM
Location: 203AB

Abstract Content : Coordinating reactive power (VAR) control between sub-transmission and distribution level of power grids may help reducing the amount of investment on additional VAR resources to enable high penetration of solar PV resources. To achieve potential reduction in the investment on VAR equipment by leveraging the available resources at different voltage levels through proper coordination, a tool with capabilities to model integrated sub-transmission and distribution systems to incorporate network constraints and VAR resource characteristics and to determine the minimum cost investment plan using these inputs, would be very useful. In this task, prototype of such a VAR planning tool is developed. It essentially deploys optimal power flow technique that solves network equations with an objective to minimize the investment on VAR equipment. This tool will aid power system planners to add reactive power resources, particularly when just coordinated operation of existing assets is not sufficient to increase PV penetration.
Based on a comprehensive review of existing VAR planning approaches and understanding of practical system requirements through engagement with utility personnel, an optimal power flow model was developed. In addition to the cost of VAR equipment, the tool can consider other relevant elements in the objective functions depending on the planning goal, such as penalties for voltage violation, system losses. While the current prototype considered only sub-transmission level VAR equipment as candidates for new VAR equipment, ground work was performed to incorporate distribution level assets (e.g., smart inverters) in the next stage of development. For each year within the planning horizon, the tool solves optimization model to find the minimum investment VAR equipment locations and sizes for extreme scenarios of load and PV deployment creating voltage limit violations. Then, analysis is performed using year-long data to examine if the determined VAR plan mitigated all potential violations year-round. If not, then the planning optimization process is repeated till the voltage management performance is acceptable. Once this criterion is met, the VAR equipment investment plan is finalized through required economic evaluations.
Model of a real-world sub-transmission system was used to test the developed prototype. Analyzing hourly voltage profiles at 44 and 100 kV buses of utility over an entire year, buses that would need VAR compensation were identified. Using traditional QV analysis approach, a base case VAR investment scenario was established. In comparison, the developed VAR planning tool generated an lower cost investment plan that maintains voltage within 0.5% of the target. With further refinement, the tool would be able to provide more optimum investment options with better voltage management performance.


Nader Samaan

Senior Power Systems Research Engineer
Pacific Northwest National Laboratory

Nader Samaan is a senior power systems engineer at Pacific Northwest National Laboratory (PNNL) performing research in the area of renewables integration and transmission planning since 2009. He is the principal investigator (PI) for SunShot National Laboratory Multiyear Partnership (SuNLaMP) project that develops planning and operational tool to enable high penetration of distributed PV through the optimization of sub-transmission voltage regulation. He is the PI for the Dynamic Contingency Analysis Tool (DCAT) that introduces a hybrid steady-state and dynamic analysis approach for cascading outage analysis. He was PNNL technical lead for a study that investigates the impact of high distributed PV penetration of the Duke Energy Carolinas and Florida systems. He was the PI/project manager (PM) for NWPP EIM benefits analysis study that assessed the potential economic benefits of energy imbalance market in the NWPP. He has been also the PI/PM for the WECC VGS balancing authorities cooperation study that investigated cooperation benefits between WECC balancing authorities with high penetration of renewable generation. He has published more than eighty technical papers and reports.
Prior to joining PNNL he has worked in EnerNex corp., Knoxville, TN as a power systems engineer for four years. During this period he has gained extensive experience in the area of wind power engineering.
Prior to that, he was a visiting assistant professor at the department of electrical and computer engineering, Kansas State University during the academic year 2004-05.
Dr. Samaan is a registered professional engineer in the state of Ohio, a senior member IEEE Power Engineering Society where he is a member of the wind and solar power coordinating committee. He obtained his PhD degree from Texas A&M University in 2004, in the area of power system reliability analysis.


Send Email for Nader Samaan


Optimal Future Sub-Transmission Volt-Var Planning Tool to Enable High Distributed PV Penetration

Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for Optimal Future Sub-Transmission Volt-Var Planning Tool to Enable High Distributed PV Penetration