GridSense has worked with Baltimore Gas and Electric to implement volt/VAR control using feeder capacitor banks instead of load tap changers (LTCs) and voltage regulators (VRs).
The July issue of Transmission and Distribution World highlights the BGE effort. According to the article, "In the last decade, volt/volt-ampere-reactive (VAR) optimization became one of the most desirable applications implemented on the distribution system."
Utilities are using volt/VAR control to reduce peak demand, and thus extend infrastructure life, optimize asset utilization, and reduce the need for additional infrastructure. Aware of the industry need, GridSense has refined its transformer monitoring solution, TransformerIQ, to cost-effectively monitor right down to the residential transformer, and to measure the very low power signals emanating from equipment like voltage sensors that are integral to measuring the efficacy of volt/VAR control efforts.
The BGE smart grid pilot project posed a unique challenge. Volt/VAR optimization usually requires LTCs or VRs at the substation. However, BGE does not use these devices. Therefore, the utility developed the novel approach of installing remote communications-ready voltage regulators and regulator controllers on the pilot feeders in lieu of LTCs and VRs at the substation. BGE is also testing a volt/VAR method using only capacitor banks in order to compare the energy savings to alternate volt/VAR control methods. The utility will use the flexible TransformerIQ platform to measure critical performance parameters across all phases of the pilot.
In a pilot such as this, measurement and verification are critical. BGE hopes to determine the most effective and efficient volt/VAR methodology for its unique circumstance. It is necessary to accurately measure current and voltages across the various methodologies at multiple points in the pilot area, and particularly at the end-of-the-line where voltage tends to sag. To that end, BGE is using a fleet of GridSense TransformerIQs to measure residential transformer internal losses, oil and winding temperature, and voltage drop. In addition the utility is using GridSense LT40 distribution line monitors to track line-loss in the pilot area.
The BGE pilot was deployed in June 2012. After a period of data collection and subsequent third-party analysis, the utility plans to examine costs versus benefits to determine if a wider rollout is warranted.