ABB Power Services
Our aim is to increase systems reliability and extend the life of their equipment with concomitant gains for our customers’ competitiveness. We support our customers with high-quality services in preventive and corrective maintenance to improve risk mitigation and improved safety. ABB's service portfolio allows utilities and industrials to maximizing the return on all assets by ensuring a high reliability, reducing life cycle costs and ensuring optimized performance while lowering environmental impact.
Wednesday, September 25, 2013
Reduce operating and maintenance costs while maintaining high voltage circuit breaker reliability
Over the past several years, utilities have been faced with the challenge of reducing O&M costs while maintaining or improving reliability. While a daunting task, many utilities have achieved this goal through creative means or partnering with vendors offering new solutions. This article will highlight three of the ways utilities have accomplished this task.
Reduction of outage times
Outage times have been compressed, especially for critical transmission lines, to minimize the load put on auxiliary lines and reduce any revenue losses. Several solutions for shorter outages include sourcing ready-to-go components (major components delivered assembled, tested, and ready for installation) when rebuilding circuit breakers, utilizing a parts exchange program where previously rebuilt components are replacing the used components in a circuit breaker, or using radiography versus traditional internal inspections to cut the cost and time in half.
Extending maintenance cycles
Today’s power electrical equipment is very reliable. Under normal operating conditions, ABB, for example, calls for monthly, annual, and five-year external inspections (each inspection evaluates specific parameters), and an internal inspection at ten years. With reliability improvements some high voltage circuit breakers do not require an internal inspection at ten years. For instance, does the yearly SF6 gas analysis testing show the SF6 gas to be maintaining consistent quality and integrity? This quick, diagnostic test is a leading indicator of future reliability. It is very important to test SF6 gas every year.
When this is coupled with radiography at five years, a ten year internal inspection may be extended to twelve or fifteen years, unless the breaker is operating under full load, is in a harsh environment, or begins experiencing faults. Faults can be detected by the presence of decomposition elements in SF6 gas, which is a reliability risk.
Radiography is an X-ray of a circuit breaker’s internal components. Radiography allows you to view the breaker’s interrupter contacts, nozzles, hardware, resistor switches, rupture disks, tanks castings, mechanism latches, and springs. Radiography eliminates the need to schedule a full maintenance crew, crane, manlift, SF6 gas cart, and vacuum pump to “see” the interrupters in your circuit breaker. Typical savings are 50% of a traditional internal inspection.
Capitalizing on substation technology
While many substations were designed with yesterday’s technology, mainly for the protection and control function, those same substations are being retrofitted for a small, incremental cost to lower maintenance expenses and improve reliability. The most common application is asset monitoring devices with related communications equipment, sensors, and hardware. Asset monitoring devices continually monitor key operating and performance parameters of high voltage circuit breakers and alert users when those parameters leave the normal range for optimal, reliable operation. These conditions include interrupter wear, SF6 gas level, breaker timing, electrical controls, and the mechanical system. Advanced systems remotely monitor and notify the user of performance-related events which aids in root cause analysis during the repair stage. Continually knowing the status of your breaker allows you to optimize work schedules. For example, one customer with a Circuit Breaker Sentinel system monitoring their critical transmission line schedules maintenance during normal work hours, saving overtime dollars that were previously spent on emergency outages.
Along this same line, another new technology that is making waves is ABB’s asset monitoring device, CBS Lite coil signature analysis. The health of the coil, and the health of the breaker are continually monitored with this device. Utilities no longer need to take an outage and manually check the health of the coil in the control cabinet with a timing device, such as an oscilloscope.
If any of the solutions described in this article sound helpful, contact ABB High Voltage Service (724-696-1300) for more information about lowering costs and improving reliability.