Reliability Performance
Source: www.aepsustainability.com
Energy reliability
The electric generation and delivery systems must be modern, reliable and able to handle diverse fuels and technologies. They also must be able to keep up with customer demand.
Overall reliability is measured by the average number and duration of sustained outages on the distribution system. System Average Interruption Frequency (SAIFI) represents the average number of interruptions a customer experiences while System Average Interruption Duration (SAIDI) measures the average number of minutes of each outage.
Distribution -- the infrastructure and the processes that deliver electricity from high-voltage transmission lines to customers’ homes and businesses -- continues to improve as better tools and processes are developed to manage the system. Several challenges remain, however.
Preventative vegetation management is critical to reliability and is one of the most proactive measures to reduce interruptions. Scheduled tree trimming is more cost effective and provides greater reliability than simply responding to overgrown vegetation. Cutting vegetation once it is entangled in the line requires more time while increasing the risk of injury and customer outages.
Storage technology will also enhance grid reliability. The sodium sulfur, or NaS, battery will improve grid performance in remote areas. Future storage projects will center on community energy storage, which uses lithium-ion battery technology. This technology is expected to become less expensive as the batteries become widely used in Plug-In Hybrid Electric Vehicles.
AEP’s 1st Commercial Energy Storage System in Charleston, WV
Source: AEP
What AEP is doing
AEP’s overall reliability has also improved. Rather than focusing on single-year numbers, AEP has begun using a three-year rolling average, which evens out weather-related outages. We believe this is a more meaningful measure that better reflects changes in the overall status of the system. The three-year SAIFI average was 1.470 in 2009, compared with 1.526 in 2008. The SAIDI average was 198.1 in 2009 versus 201.0 the previous year.
Many of AEP’s assets are at or near the end of their useful and depreciable life. AEP has a pole inspection program to continually evaluate the status of all distribution poles.
New, higher efficiency equipment is available that is used to begin replacing aging assets while also achieving demand and energy efficiency goals.
Line Equipment Analysis Device
Source: www.aepsustainability.com
AEP has new tools and processes to enhance our ability to manage the system. AEP began using a Line Equipment Analysis Device (LEAD), an electronic “sniffer” developed in AEP’s own labs that detects interference caused by cracked insulation or other difficult-to-detect failures.
Vegetation Management
Source: AEP
In the area of preventative vegetation management, PSO and AEP Ohio have adopted four-year trim cycles, and similar requests have been submitted for Kentucky Power, the Texas portion of SWEPCO and in Michigan.
AEP conducted an employee-led study of outages and as a result adopted new maintenance procedures within breaker zones that should lead to increased reliability. By better maintaining breaker zones, we have been able to improve reliability significantly for our customers.
