Reactive power planning with voltage stability enhancement using covariance matrix adapted evolution strategy

Abstract

SUMMARYThis paper presents the application of Covariance matrix adapted evolution strategy (CMAES) to reactive power planning (RPP) problem by minimizing the combined total cost of energy loss and the allocation cost of additional reactive power sources. Voltage stability index (L-index) is considered as an additional constraint in order to include the system stability into account. To improve the search efficiency of CMAES, penalty parameter-less scheme is employed for constraint handling. To determine the performance of the CMAES method on reactive power planning problem, IEEE-30 bus test system and Tamil Nadu Electricity Board (TNEB)-69 bus system (a practical system in India) are taken. For comparison purposes, the results of real-coded GA (RGA), particle swarm optimization (PSO), sequential quadratic programming (SQP), and Broyden-Fletcher-Goldfarb-Shanno (BFGS) methods are considered. The simulation results reveal that the CMAES algorithm performs better in terms of energy cost, investment cost, and consistency in getting optimal solution. Karush-Kuhn-Tucker (KKT) conditions are also applied on the best solution obtained using CMAES algorithm to substantiate a claim on optimality.

Implementation of Static Line Voltage Stability Indices for Improved Static Voltage Stability Margin

“…e reactive reservebased contingency constrained optimal power flow (RCCOPF) concept was formulated as the reactive reserve constraint to improve the voltage stability margin of postcontingency states [21]. e L-index was adapted as the voltage stability constraint to maintain the voltage level in an economical way [22,23]. e voltage security-constrained OPF (VSC-OPF) formulation that incorporates margin enhancement constraints (MEC) was proposed in [24] to control the reactive power for the given voltage stability criteria.…”

Modified tangent vector‐based voltage stability constrained optimal power flow considering limit‐induced bifurcation

“…The static VSI‐based method uses static VSIs such as VCPI [19–23], MSV [20, 24–26] and L‐index [20, 27–31] as an objective function or constraint of the OPF problem. Although these VSIs approximately indicate the proximity of the system to the voltage collapse point, there is no established way to determine the appropriate threshold value corresponding to the required VSM.…”

A comparative study of VSC-OPF techniques for voltage security improvement and losses reduction

“…Therefore, the variety of voltage stability analysis methods and the readily application of optimization algorithms for voltage stability problem have lead to propose optimal power flow formulations that include voltage stability criteria [14]. The voltage issue is introduced in the conventional OPF model in two ways; first it can be added as voltage stability constraint in the OPF constraints [15][16][17][18][19], the other approach is to incorporate voltage stability as objective function to enhance the system voltage security. In [20] and [21], the objective function is the minimum singular value (MSV) of the power flow Jacobian matrix which must be improved to prevent voltage collapse.…”