New York utility Consolidated Edison has reported avoiding an impressive 20,000 outages so far this year, including 5,000 of them in one area during the first weekend in July, due to the installation of new grid technologies.
The US$1 billion program for storm hardening following Sandy has seen the installation of thousands of sectionalizing fuses on its overhead system, as well as reclosers. Further storm-hardening projects will continue into 2015 and 2016 [Engerati-Asset Management Before Its Urgent].
“The post-Sandy storm hardening improvements are paying service reliability dividends for our customers,” comments Robert Schimmenti, Con Edison’s vice president of Engineering and Planning.
4kV system upgrade
As part of its distribution system modernization, Con Edison is seeking to optimize 4kV distribution grid performance, reduce electrical losses, enhance performance monitoring and analysis, and improve voltage control methods.
The portion of Con Edison’s distribution system that uses 13kV and 27kV equipment has a greater percentage of substations and feeders currently equipped with automated digital controls and access to SCADA systems. However, the 4kV grids use analog systems with electromechanical controls and typically serve areas where load growth has been modest. Replacing the 4kV grids with higher voltage systems is cost prohibitive in New York due in part to the high cost of real estate.
The project, partially supported by a Smart Grid Investment Grant from the US Department of Energy (DOE), includes the installation of pole mounted distribution capacitors, load tap changer (LTC) controllers at 4kV unit substation transformers, power quality and battery monitoring systems, and development of 4kV grid models for enhanced load flow analysis.
Key project results
1. Asset utilization and capacity management
i. Increased 4kV unit substation capability by 31.1MVA or 2.8% under peak conditions with net savings of US$15.7 million.
ii. Reduced 4kV system primary losses by 2.3 percent under peak conditions.
2. Voltage controls for reactive power management and energy efficiency
iii. Reduced reactive power requirements at the aggregate level of 33 substations in Queens by about 12.3% and 9.9% over a one-year test period through the application of advanced LTC controls.
iv. Increased power factor at these same substations by about 2% and 1% over the same one-year test period.
v. Reduced annual system energy losses by 4,500 MWh that saved an estimated $0.34 million in annual energy costs and reduced CO2 emissions by about 340 metric tons.