Optimal Spinning Reserve of Power Systems Considering Forecasting Error of Load and Wind Power Generation under Market Environment (OSRNordic)

In order to operate power systems under secure conditions, it is necessary to control the system frequency at its normal value. The system frequency deviates from the nominal value when imbalance between generation and consumption occurs. Such imbalance may be caused by a sudden generating unit outage or a sudden load change. In modern power systems integrated with wind farms, the extend of system imbalance is further aggravated due to the stochastic variation of wind power generation. Therefore, to re-establish the balance between generation and load, a certain amount of active power is required to be kept online as spinning reserve (SR).



Both the SR requirement of the system and the SR provision of individual generators need to be determined before the real time operation of a power system. SR is usually determined with a standard commitment (UC) optimization problem, in which the sum of SR provision from individual generators should be no less than a minimum system SR requirement. Normally, this minimum amount of system SR is specified according to a deterministic criterion, e.g. equal to the capacity of the largest online generation.



Such an approach of specifying and allocating SR may be appropriate if the system operator has a perfect forecast of future load demand, wind power and market information. In reality, however, forecasting errors always exist. Consequently, the standard UC formulation cannot provide optimal solutions of SR allocation, which may lead to a high cost or even jeopardize the security of the system operation.



The key to solving the above problem is to include the forecasting error (e.g. variance and correlation of the error) in the UC formulation. However, the inclusion of wind power and electricity market makes it a challenging task to tackle.



On the basis of the foregoing issues, the objective of this project is:



To investigate and determine the optimal SR requirements for modern power systems integrated with large-scale wind farms, while considering the forecasting error of load and wind power generation as well as the forecasts of market prices and system imbalances. The project will also study the effect of using energy storages on the determination of system SR within the framework of UC issues. Furthermore, the project will investigate a combined operation of wind farm and energy storage system and their capability to provide SR.