Aleksandar Vukojevic

Integrated volt/var control using single-phase capacitor bank switching

Electric utility distribution power systems as operated today are rarely perfectly balanced. While feeders with single-phase voltage regulators (VR) tend to be more balanced, feeders with substation transformers that have load tap changer (LTC) or line capacitors only for voltage control are more challenging to balance. BGE distribution system has very few LTCs and VRs. Both voltage and VAr control is done by utilizing the line capacitor banks that are switched as a function of substation transformer loading and low side bus voltage. Utilizing this approach, voltage balancing on feeders results in a set of unique challenges. As a result, BGE developed new approach that includes the use of capacitor bank controllers that support single phase capacitor bank switching along with singlephase voltage and current sensors installed at capacitor bank locations for voltage and current measurements. Capacitor banks controllers will be equipped with an internal battery and will also serve as fault circuit indicators. This paper introduces a new approach for integrated volt/VAr control that has two objectives: minimizing the overall energy demand known as Conservation Voltage Reduction (CVR) and improving the voltage balancing index (VBI) along the feeder based on singlephase capacitor bank switching. BGE intends to use the internally developed IVVC algorithms for the approach and is in the process of piloting this solution at two of its substations.

Distribution transformer loading with deferred loads

Introduction of deferrable loads such as electric vehicles, on the distribution system will have major impact on the electric utility system operations and especially the loading of the distribution transformers. This paper addresses challenges associated with overloading on the distribution transformer and offers new approach to reducing its loading and extending its lifetime based on the pricing signals and customer preference.

Making a Smart Grid Case: Fault circuit indicators

Baltimore Gas and Electric (BGE) started implementing distribution automation (DA) into its distribution system operations since early 2000. With the advances in communications and technology, the number of available DA applications has significantly increased. In order to improve the system reliability, BGE decided to utilize fault circuit indicators (FCIs) as part of its Smart Grid Pilot Program. The purpose of this paper is to introduce the optimization technique that has been developed in order to determine the optimal location for any desired number of fault circuit indicators on the six test feeders, and provide the expected CAIDI values, cost-benefit analysis and discounted cash flow analysis, in order to make a business case for the FCI implementation across the whole system.