Dynamic Reserve Estimating Method with Consideration of Uncertainties in Supply and Demand

Abstract

-Renewable energy integration and increased system complexities make system operator maintain supply and demand balance harder than before. To keep the grid frequency in a stable range, an appropriate spinning reserve margin should be procured with consideration of ever-changing system situation, such as demand, wind power output and generator failure. This paper propose a novel concept of dynamic reserve, which arrange different spinning reserve margin depending on time. To investigate the effectiveness of the proposed dynamic reserve, we developed a new short-term reliability criterion that estimates the probability of a spinning reserve shortage events, thus indicating grid frequency stability. Uncertainties of demand forecast error, wind generation forecast error and generator failure have been modeled in probabilistic terms, and the proposed spinning reserve has been applied to generation scheduling. This approach has been tested on the modified IEEE 118-bus system with a wind farm. The results show that the required spinning reserve margin changes depending on the system situation of demand, wind generation and generator failure. Moreover the proposed approach could be utilized even in case of system configuration change, such as wind generation extension.

Cost Analysis Method for Estimating Dynamic Reserve Considering Uncertainties in Supply and Demand

“…Finally, methods to calculate hourly reserve margins considering the uncertainties of load forecast, generation outage, and wind power generation are researched [23][24][25][26][27]. In [23], the required operating balance reserve is estimated with consideration given to the load forecast error and unavailable capacity due to unit outage in a time horizon of 1-48 h. Both [24,25] generate probability functions of conventional generation outage, load forecasting uncertainty, and wind power forecast uncertainty, and the reserve margin is estimated considering the trade-off between risk and reserve cost.…”

“…In [26], a new random variable which consists of uncertainties of load shedding and wind curtailment is defined, and conditional value-at-risk (CVaR) is adopted to determine risk reserve requirement. In [27], the spinning reserve margin is determined from a defined term called the short-term reliability of balance, which is calculated from the probabilistic models of uncertainties.…”