Operation planning studies are essential in maintaining and operating a reliable and secure power system. They are based on existing system elements and aim to identify the operating limits within which reliability criteria are satisfied. Traditionally these studies are performed using deterministic criteria. It requires that a power system must be able to withstand an outage of any single component without violating any operating limits. However, it has been recognised that the deterministic method may no longer be adequate to deal with modern power systems with high level of renewable energy penetration.udIn particular, high variability and uncertainty of wind power generation may lead to significant load-generation imbalance resulting in large frequency deviations. This increases system operation risk, especially in small and isolated power systems which have low inertia and limited capabilities to provide frequency responses. Therefore, there is a need for investigating alternatives to current power system operation planning approaches to cope with the uncertain nature of the intermittent generation.udThis thesis proposes a novel probabilistic risk-based approach to evaluate power system security quantitatively in short-term (e.g., hour/s up to a day) operation planning with significant wind power generation in order to help facilitate day to day system operation. The proposed approach deals with steady-state voltage and overload evaluations as well as frequency deviation analysis. Load flow calculation techniques are used to perform the steady-state voltage and overload evaluations for post-disturbance system conditions. An analytical method to approximate frequency deviations is developed in order to assess the consequence of these frequency events without performing dynamic simulations. As a result, the frequency deviation analysis can be run simultaneously with the steady-state voltage and overload evaluations in the proposed risk assessment. The system operation risk is defined as the product of the probability and severity of system operating states in terms of expected load interruption cost. The risk calculation takes into account both the randomness of contingencies as well as the uncertainty of operating conditions caused by load and wind power generation forecast errors. The thesis also formulates a security constrained economic dispatch approach to determine operating reserve requirements in wind integrated power systems. This approach co-optimises operation risks resulted from inadequacy of system frequency responses and operation cost including energy price and cost of reserve provision. The effectiveness of the proposed approaches is illustrated by their application to a simplified model of Tasmanian power network, Australia under various system conditions and wind generation scenarios.
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