Quantification of Intra-hour Security-Constrained Flexibility Region

Abstract

Rapid growth of renewable energy sources (RES) in the generation capacity mix poses substantial challenges on the operation of power systems in various time scales. Particularly in the intra-hour time scale, the interplay among variability and uncertainty of RES, unexpected transmission/generation outages, and short dispatch lead time cause difficulties in generationload balancing. This paper proposes a method to quantify the intra-hour flexibility region. A robust security-constrained multiperiod optimal power flow (RSC-OPF) model is first constructed to quantify the frequency, magnitude, and intensity of insufficient flexibility. The randomness of RES is captured by uncertainty sets in this model. The N-k contingency, spinning reserve, and corrective control limit constraints are included. This model is then cast into a two-stage robust optimization (RO) model and solved by the column-and-constraint generation (C&CG) method. The emergency measures with a least number of affected buses are derived and subsequently assessed by the post-optimization sensitivity analysis. Finally, the operational flexibility region is determined by continuous perturbation on the RES penetration level and the forecast error. The IEEE 14-bus system and a realistic Chinese 157-bus system are used to demonstrate the proposed method.

Flexible Coordination Optimization Scheduling of Active Distribution Network With Smart Load

“…Hence, scheduling properly FRs at different time scales can counteract uncertain voltage fluctuation and deviation [9]. Reference [10] put forward a robust security-constrained multi-period optimal power flow model to quantify the insufficient flexibility in the intra-hour time scale. Regarding the distribution of flexible-regulation resources, a bi-level programming model is established.…”

Adaptive uncertainty sets‐based two‐stage robust optimisation for economic dispatch of microgrid with demand response

“…To solve the above two‐stage robust optimisation model, the column and constraint generation (C&CG) method is applied in this paper. The C&CG method [23] decomposes the two‐stage robust optimisation into a master problem and a subproblem and then solves them iteratively. The master problem is expressed as follows: where k is the maximum iteration number.…”

Operational flexibility of active distribution networks: Definition, quantified calculation and application

“…[8] proposed a definition of operational flexibility as the regulating capacity and ramping capacity that the network can provide. The authors of [9] and [10] defined it as the distance from the actual operating point to the flexible boundaries. The definitions in [8], [9] and [10] only apply to transmission networks, which are not appropriate for ADNs.…”

“…The authors of [9] and [10] defined it as the distance from the actual operating point to the flexible boundaries. The definitions in [8], [9] and [10] only apply to transmission networks, which are not appropriate for ADNs. The existing works mainly focus on the regulating ability of active power in the network, while the regulating ability of reactive power is ignored.…”