Security constrained optimal power flow (SCOPF) is an important operation function for dispatching centers of current power systems. It optimizes operating conditions of the system, while saves its security. However, SCOPF in its present form focuses on a single time interval, which is known as static SCOPF. A multi-period SCOPF model, referred to as dynamic SCOPF (DSCOPF) in this paper, is presented. It extends static SCOPF to multi-period frameworks considering the inter-temporal constraints. The proposed DSCOPF is a more practical operation function and can optimize operating conditions of the system more realistically compared to traditional SCOPF. Moreover, to solve this DSCOPF model, considering its nonlinear and non-convex behavior, a new stochastic search method is presented, which is an enhanced version of artificial bee colony (ABC) algorithm. The proposed enhanced ABC (EABC) has high exploration capability and can discover different areas of the solution space. Also, it is a robust algorithm and has low sensitivity with respect to the initial population. Effectiveness of the proposed EABC is extensively illustrated on various test cases. generation cost coefficients of ith unit with valve loading effects down ramp rate limit of ith unit generation cost function of ith unit conductance and susceptance of the branch connected between ith and jth buses, respectively number of branches number of buses, number of buses excluding the slack buses and number of PQ buses, respectively number of shunt compensators number of fuel options of ith unit number of units of the power system number of POZs for ith unit number of phase shifters number of prohibited operating zones of ith unit number of tap-changing transformers lower and upper bound for kth prohibited operating zone (POZ) of ith unit minimum and maximum active power generation limits for ith unit active power generation and demand of ith bus in hour t, respectively a vector including all P G,i,t variables phase shifter setting for ith phase shifter in hour t minimum and maximum limits for ith phase shifter setting reactive power injection of ith shunt compensator in hour t minimum and maximum limits for reactive power injection of ith shunt compensator minimum and maximum reactive power generation limits for ith unit reactive power generation and demand of ith bus in hour t, respectively number of hours of the operation horizon tap-changer setting for ith transformer in hour t minimum and maximum limits for ith tap-changer setting up ramp rate limit of ith unit voltage magnitude of ith bus in hour t minimum and maximum limits for voltage magnitude of ith bus apparent power flow of kth branch in hour t apparent power flow limit for kth branch system reserve required in time interval t phase angle difference between buses i and j in hour t 
Security constrained multi-period optimal power flow by a new enhanced artificial bee colony