In this paper, an exchange market algorithm (EMA) approach is applied to solve highly non-linear power system optimal reactive power dispatch (ORPD) problems. ORPD is most vital optimization problems in power system study and are usually devised as optimal power flow (OPF) problem. The problem is formulated as nonlinear, non-convex constrained optimization problem with the presence of both continuous and discrete control variables. The EMA searches for optimal solution via two main phases; namely, balanced market and oscillation market. Each of the phases comprises of both exploration and exploitation, which makes the algorithm unique. This uniqueness of EMA is exploited in this paper to solve various vital objectives associated with ORPD problems. Programs are developed in MATLAB and tested on standard IEEE 30 and IEEE 118 bus systems. The results obtained using EMA are compared with other contemporary methods in the literature. Simulation results demonstrate the superiority of EMA in terms of its computational efficiency and robustness. Consumed function evaluation for each case study is mentioned in the convergence plot itself for better clarity. Parametric study is also performed on different case studies to obtain the suitable values of tuneable parameters. susceptance of the lines connecting between bus i and bus j objective function conductance of transmission line between bus i and bus j stability index of j th load bus number of generator busses or PV busses number of load busses or PQ busses number of tap changing transformers number of transmission lines number of shunt capacitors active power loss in MW minimum limit of active power output (MW) of slack generator (G 1 ) maximum limit of active power output (MW) of slack generator (G 1 ) limiting value of active power output (MW) of slack generator (G 1 ) active power output (MW) of slack generator G1 active power generation (MW) of i th generator active power load demand (MW) at i th bus minimum limit of reactive power output (MVAr) of i th generator maximum limit of reactive power output (MVAr) of ith generator reactive power generation (MVAr) for i th generator reactive power load demand (MVAr) at i th bus limiting value of reactive power generation (MVAr) of i th generator reactive power output of slack generator G1 (MVAr) reactive power output of Shunt capacitor (MVAr) minimum value of reactive power output of i th shunt capacitor maximum value of reactive power output of i th shunt capacitor reactive power output of 1 st shunt capacitor (MVAr) reactive power output of i th shunt capacitor (MVAr) apparent power flow through L th transmission line (MVA) apparent power flow limit of L th transmission line (MVA) max. limit of apparent power flow through L th transmission line (MVA) shares of shareholders lower limit of j thshare of i th shareholder upper limit of j th share of i th shareholder variation in the share of K th shareholder of the third group tap positions of tap changing transformers minimum position of k th tap changing transformer maximum position of k th tap changing transformer tap position of the first tap changing transformer tap position of the k th tap changing transformer voltage of first generator G 1 (p.u). magnitude of the load voltage (p.u) voltage magnitude of the first load bus (p.u) voltage magnitude of the i th bus (p.u) voltage magnitude of the j th bus (p.u) minimum voltage of i th generator (p.u) maximum voltage of i th generator (p.u) voltage of i th generator (p.u) minimum voltage of i th load bus or PQ bus (p.u) maximum voltage of i th load bus or PQ bus (p.u) reference voltage magnitude at i th load bus (p.u) voltage phase angle difference between bus i and j penalty factor associated with slack bus power output penalty factor associated load voltage penalty factor associated with generators reactive power generation penalty factor associated with line loadings 
Exchange market algorithm based optimum reactive power dispatch