Interior point models for power system stability problems

Identification of voltage collapse points and weak buses under security constraints using hybrid particle swarm optimization technique

“…In general power flow solution, unknown voltage magnitudes and phase angles are obtained considering some practical constraints [6][7][8][9][10][11]. The state variables (x) of power flow problem are signified as unknown power flow variables such as voltage magnitudes of load buses (or PQ buses), phase angles of slack bus (or reference bus), real power generation of slack bus and generation reactive power [8,9]. The state variables (x) of power flow problem are signified as unknown power flow variables such as voltage magnitudes of load buses (or PQ buses), phase angles of slack bus (or reference bus), real power generation of slack bus and generation reactive power [8,9].…”

“…Although this algorithm applies same Newton-Raphson method, another four complex implementation such as prediction, correction, step-length control, and parameterization are required to obtain solutions [7]. The implementation of this method is complicated under more security constraints and difficulties may be faced if the system is already near the maximum loading [8,9,[12][13][14][15]. The implementation of this method is complicated under more security constraints and difficulties may be faced if the system is already near the maximum loading [8,9,[12][13][14][15].…”

“…Other than CPF, VCP or voltage stability problems are solved using successive quadratic programming (SQP), interior point methods [8,9]. Including the differentiation of the constraints and construction of matrixes, the sequential quadratic programming (SQP) algorithm is developed as optimization problem whose objective is to maximize the load on the system in some direction satisfying some security constraints.…”

“…With the ongoing expansion and growth of the electric utility industry, including deregulation in many countries, numerous changes are continuously being introduced to a once predictable business [1][2][3][4][5]. The continuous increase of load demand along with social, environmental, and economical constraints lead the power systems to operate closer to their loadability limits, and voltage instability becomes more likely to occur [4][5][6][7][8][9][10]. Essential actions such as production of industries, electrical appliances, laboratory experiments, electric transport, urban water system, traffic control signals, security systems, medical emergency operations, and so on are collapsed when the electric power systems collapse, that is, social, economical and other important support systems are fallen down for voltage collapse [11][12][13].…”

“…Starting from known solution, CPF used a tangent prediction to evaluate a subsequent solution corresponding to a different value of loading factor (l). The implementation of this method is complicated under more security constraints and difficulties may be faced if the system is already near the maximum loading [8,9,[12][13][14][15].…”