An Experience With ASME PTC-70 Ramp Rates

ASME PTC-70 is a new performance test code for determination of ramp rates. Ramp rates are often required by dispatch agencies and independent system operators (ISOs). They are used to ensure the reliability of the electric power grid to ensure enough available power is achievable in the time frame required — for instance, if any generating unit suddenly comes offline, the remaining units online at that time will need to pick up the required load. A mix of both spinning reserve and non-spinning reserve may be needed. The published ramp rates declared by the generating units along with available reserve power are used by system operators to balance the potential for lost generation due to scheduled, expected and emergency events. An ASME committee was formed late in 2007 to develop PTC 70 after it was determined that there was no standard methodology to determine ramp rates in the US. Just over one year later, PTC 70 was sent to publishing, and is now available for use by industry. Published in 2009, the amount of experience with PTC 70 is limited. One such experience is described here, including setup, testing and results of the ramp rate test at a dual LM6000 simple cycle facility.