Transmission Security Enhancement under (N−1) Contingency Conditions with Optimal Unified Power Flow Controller and Renewable Energy Sources Generation

Abstract

Introduction Transmission system security management under (N−1) line contingency is one of the typical and essential tasks in power system operation and control. This paper examines the impact of the optimal unified power flow controller (OUPFC) and renewable energy sources (RES) on the severity of (n−1) line contingency on transmission system security. Materials and methods To test the performance of OUPFC device under single line contingency conditions, an optimal power flow (OPF) based multi-objective function is formulated using real power loss and line collapse proximity indicator (LCPI). Primarily, the optimal location of the OUPFC is determined using LCPI index and then (n−1) contingency analysis is performed by considering OUPFC device at different RES generation levels. Here, the control variables of OUPFC, tapchangers, VAr injections, output power of conventional energy sources (CES), bus voltages and bus angles are optimized with two different variants of the cuckoo search algorithm (CSA) namely (1) dynamically increasing switching parameter in power of three (CSA1) and (2) exponentially increasing switching parameter (CSA2). Conclusion The simulation results of various case studies on a standard IEEE-30 bus test system have shown the superiority of CSA2 in solving the multi-objective, non-linear complex optimization problem over CSA1 and time-varying acceleration coefficient-particle swarm optimization (TVAC-PSO). Also, the ability of OUPFC for managing the impact of (n−1) line contingency and variable RES generation is shown in terms of decreased real power loss, improved voltage profile and enhanced security margin.

Effective Modeling of OUPFC Into Newton-Raphson Power Flow Considering Multi-Control Modes and Operating Constraints

“…The optimal parameters setting OUPFC has been determined for transient stability of the system [24]. The placement and rating of the OUPFC has been assigned for power loss reduction and line collapse proximity indicator [25]. Enforcement the operating constrains is based on alleviating the specified values which are controlled by the FACTS.…”

“…It should be highlighted here that handling the constraints at their maximum values to maximize the utilization of the used controller. The OUPFC is an efficient controller consists of a phase shifting transformer combined with a UPFC [22,23,25,26]. Thus, the OUPFC is a combined series shunt controller, and it has ability to control the active and reactive power flow in TL.…”

“…P. Avaz Pour et al determined the parameters of the OUPFC for the transient stability enhancement [26]. The authors in [25] determined the optimal rating and location of the OUPFC using the cuckoo search algorithm for the power losses reduction and enhancing the system security.…”

Data clustering based probabilistic UPFC allocation for improving power system reliability considering correlated uncertain variables

“…Sensitivity analysis was used for optimal location of TAST/UPFC in this reference. The optimal allocation of UPFC to security management under (N − 1) line contingency is presented in Reference 48. Line collapse proximity indicator (LCPI) is considered as security index.…”

Performance and security enhancement using generalized optimal unified power flow controller under contingency conditions and renewable energy penetrations

“…The economic operation is performed in power systems to analyze the effect of OUPFC under weather changing conditions as well as variable loading conditions [23]. Transmission system security is enhanced under single line contingency conditions with OUPFC device under different renewable energy generations and is proposed in [24].…”