Design of Flexible Ramping Product Coupled with Spinning Reserve

In order to solve the problem of short-term strong gradient changes in net load caused by the high proportion of renewable energy integration, flexible ramping products have been applied in many regions. However, most of the existing ramping products rely on the abundant local power regulation capabilities, which aim to optimize the resource allocation of rapid units, while ignoring the full release of the regulation capabilities of slow units. In most power systems of China, where renewable energy accounts for a high proportion and coal power is the main regulatory resource, the high proportion of wind power and photovoltaic integration generate a huge demand for flexible ramping, while the slow regulating rate of coal power causes the overall ramping rate to be scarce. In addition, a large amount of intra-day regulation space of coal power units has been occupied by spinning reserve products. The simple application of existing flexible ramping products will encounter serious shortages on the supply side and make the prices of flexible ramping products remain high, as well as increase the risk of massive load loss in the system. To cope with the challenges faced by such systems that are short in regulation capabilities, this paper designs a flexible ramping product coupled with spinning reserve product. By replacing the rapid coal power units which winning the bid in the day-ahead spinning reserve product with slow coal power units in intra-day stage, it fully releases the regulation capabilities of slow coal power units, so as to effectively reduce the procurement expenditures of system flexible ramping and the purchase costs in electric energy market. Meanwhile, massive abandoned wind-photovoltaic power or load loss due to insufficient flexible ramping capabilities of the system is also reduced. This paper verifies the effectiveness of the designed product through a simplified actual case study in Ningxia, China.