Five Year System Planning Studies

Overview
This type of study includes all category B and C contingencies for summer and winter, peak and off peak conditions. It also can include changes in power factor, loading pattern and level, and transfer pattern and level. Voltage limit violations are determined for each contingency evaluated and an integrated thermal and voltage security assessment is provided. System Planning and Design changes must be proposed for each area and loadpocket problem. Intellicon estimates this study will take three to six months to complete.

Study Tasks
  • Uses Contingency Vulnerable Areas to determine all the subnetworks that can be vulnerable to voltage instability
  • Uses Voltage Collapse Contingency Selection to find all single and double contingencies that have no solution or close to no solution and the subnetworks, areas and loadpockets they affect
  • Determines Postured Voltage Rescheduling Unit Commitment and Load Shedding to guide unit commitment, under voltage capacitor switching, and under voltage load shedding control that assures voltage stability in each load pocket by dramatically increasing reactive reserves in the control regions of the loadpockets
  • Performs up to 20,000 V-Q curves and P-V curves for different contingencies at different buses with different loading patterns and levels, transfer patterns and levels, and power factor changes using the Comprehensive V-Q Assessment and Comprehensive P-V Assessments to assess critical voltage reactive margins and loading and transfer margins for each loadpocket
  • Performs Batch Contingency Selection for several hundred thousand contingencies to assess whether the voltage instability problems in each load pocket are solved with adequate reactive margins for every contingency
Benefits

    FERC has stated that conventional voltage instability study methods do not determine all the areas and all the contingencies for any area. It has also in effect stated the preventive solutions are not robust which is why ten year designs must be redone every few years and current PV and V-Q methods margins do not correlate with assuring security. Most voltage stability studies are limited by the fact they do not consider all the areas, determine all the contingencies that cause voltage instability in the area, and properly address the cause of the voltage instability and where that voltage instability problem is initiated.