Dynamic security constrained optimal power flow/VAr planning

Abstract

Traditionally Security Constrained Optimal Power Flow and VAr planning methods consider static security observing voltage profile and flow constraints under normal and post contingency conditions. Ideally, these formulations should be extended to consider dynamic security. This paper reports on a B.C. Hydro/CEPEL joint effort establishing a Dynamic Security Constrained OPF/VAr planning tool which considers simultaneously static constraints as well as voltage stability constraints. This paper covers the details of formulation and implementation of the tool together with the test results on a large scale North American utility system and a reduced Brazilian system.

Reactive Power Reserve Improvement Using Power Systems Inherent Structural Characteristics

“…The stressed condition consists of lost of major lines, transformers, generators or a situation where load gradually increase until the network cannot support such load demand corresponding to the nose curve point D in Figure 1, referred to as voltage collapse point [15]. A power system with operating voltage at point A is ill conditioned, because, it is operating below the nominal voltage limit.…”

“…Due to the non-convex nature of the problem, many optimisation techniques could easily be trapped in local minima [11]. Secondly, ill conditioned networks could lead to suboptimal solutions because of the need to locate fictitious reactive power compensators first, to achieve convergence of load flow before the loadability of the network can be properly addressed [15]. Thirdly, the large sizes of practical networks could be a challenge when the nonlinearity of the problem formulation is fully considered, since large solution variables would need to be generated and may present memory storage issues [13].…”

Allocation of Wind Capacity Subject to Long Term Voltage Stability Constraints

“…Inclusion of voltage stability constraints in the AC OPF has been proposed in [5]- [9]. The authors of [5] propose a security constrained OPF which considers both static and voltage stability constrains.…”

“…Inclusion of voltage stability constraints in the AC OPF has been proposed in [5]- [9]. The authors of [5] propose a security constrained OPF which considers both static and voltage stability constrains. Bender's decomposition is used to decompose the preventive and corrective actions which are based on the four cases describing the network normal and stressed base and post contingency cases.…”

Optimal allocation of wind generation subject to voltage stability constraints

“…The voltage stability constrained OPF proposed in [4] considers the total transfer capability limit for cost minimization in reactive power planning. In [5] a series of preventive-corrective tools are introduced to the OPF in order to consider both grid code steady-state voltage limits and stability margin. Bender's decomposition technique is used to decompose the base and contingent cases in order to supply signals for the preventive-corrective tools.…”